Clockwise is a smart calendar assistant that frees up your time so you can work on what matters

Clockwise

clockwise

What is Clockwise Software? Hello! :) We are Clockwise Software - a Ukrainian JavaScript development company with a head office in Dnipro. We have broad experience working with various projects for different industries. Our main principle is not just to create software solutions but shape them for the specific needs of each of our clients. Meet Clockwise Software’s Team Our company consists of 80+ specialists. - Chief Executive Officer (CEO) Andrei Tsygankov - Head of People Natalya Yemelyanova - Head of Sales Serhii Pedan As most of our team is spread worldwide, we’ve managed to maintain effective remote communication and cooperation. Borders and distance create no obstacles for us: we work together as one team, no matter what. The war in our country continues, but we are doing everything possible to counter the consequences. In our office, we have Starlink internet and generators to ensure the necessary working conditions for our employees in Dnipro. ; Those working remotely also have alternative and backup power supply options to ensure uninterrupted workflow even when there's no electricity. Clockwise Software’s Vision & Goals Our main goal is not just to complete tasks. We aim to offer each client an individual approach and care a lot about the results that each of our projects brings. Goal 1: We strive to provide the most up-to-date solutions compliant with the current industry requirements and trends. Goal 2: Deadline is not just a word for us. We follow the principle of delivering quality software on time so our clients don’t have to waste their valuable time and money. Goal 3: Goal 4: Our goal is to make the most qualified and talented specialists a part of our team. Our multi-level recruiting system allows us to hire talents with outstanding soft & hard skills. Our Founding Story :-) Our company's history began in 2013 when three software engineers teamed up to create a logistics app for a local manufacturing company. With time, this initiative grew into Clockwise Software -  a JavaScript development company with 80+ talented software engineers, business analysts, QA engineers, software architects, and managers. Clockwise Software’s Services 1. Product Development Services We can become a reliable software development partner for you. Just tell us your idea and expectations — we will test it and come up with the best recommendations for improving it and bringing it to life. Depending on the size and complexity of your product, we will of experienced specialists with all the skills to work on your project. Here is a list of solutions we can build for you: compose a team Online marketplaces SaaS applications Data visualization dashboards Content-sharing platforms Location-based apps On-demand services platforms Inventory/order management systems Online streaming platforms Online booking apps 2. IT Staff Augmentation We can help you cooperate with the best remote specialists (software architects, JavaScript developers, business analysts, QA engineers, and project managers) if you need to and boost its productivity or fill the gap in expertise. You can hire the necessary specialists while we take over all HR-related hassles.  Just inform us about your needs and expectations, and we will do the rest. extend your team 3. Discovery Phase We can help ensure the success of your project with the help of a discovery phase service before the development process even starts. We that require upgrades and improvements. Get reliable cost and development time estimations, software requirements specification documents, business model canvas, development plans, and other documents to help you build a robust product that the market will take advantage of. work with startups, established businesses, and products Developing a Software Solution from Scratch Thousands of people around the globe have ideas on how to revolutionize their industries with a new application. However, they mostly lack the knowledge, tech expertise, and resources to turn these ideas into reality. And they give up without even trying. Developing a software solution from scratch doesn’t necessarily have to cost millions of dollars. You can start with much smaller budgets. Moreover, the development doesn’t have to start with coding. Thorough planning and a strategic approach may save you tens of thousands of dollars. We aim to educate our clients and provide custom software development services. We teach them how to validate their idea, prove its viability and feasibility, compose an effective team, reduce software development expenses, etc. We care that our clients spend their budget in the most efficient way possible. This allows them to grow and spread innovation across the industry faster. The Future of Clockwise Software At Clockwise Software, we promote the idea of mono-stack - developing diverse tech solutions with JavaScript. This benefits our partners since their products are built within a single ecosystem and are easy to support, maintain, and scale. The rise of IoT and the creation of new connected devices run on various OSs with displays of different forms and sizes make it clear: native app development has become obsolete. Web and cross-platform development with JS allows releasing of apps for any device with a built-in browser, be it a smart fridge, a TV, or a smartphone. That’s where Clockwise Software is ready to help our partners: build apps for any platform while using the toolset of the most widespread programming language - JavaScript.

Meet Clockwise Software

Python Bokeh is one of the best Python packages for data visualization. Today, we are going to see some Python Bokeh Examples. I have also provided the Python Bokeh project source code on GitHub. Learn this easy visualization tool and add it to your Python stack. What is Python Bokeh? Python is a data visualization tool, or we can also say Python Bokeh is used to plot various types of graphs. There are various other graph plotting libraries like matplotlib, but Python Bokeh graphs are dynamic in nature, which means you can interact with the generated graph. See the below examples… Bokeh Installation 💻: Python Bokeh can be easily installed using PIP. You can install the Python Bokeh easily by running the command: pip install bokeh Now everything is ready, let’s go through the examples 🏃‍♂️… 1. LinePlot from bokeh.plotting import figure, show, output_notebook
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 3]
p = figure(title="{LinePlot Python Bokeh Example")
p.line(x, y, line_width=2)
output_notebook()
show(p) | | Live Preview Source Code 🌿 Contribute 2. Scatter Plot from bokeh.plotting import figure, show, output_notebook
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 3]
p = figure(title="Scatter Plot Python Bokeh Example by PratikPathak.com")
p.circle(x, y, size=10, color="navy", alpha=0.5)
output_notebook()
show(p) 3. Bar Chart from bokeh.plotting import figure, show, output_notebook
categories = ["A", "B", "C", "D", "E"]
values = [10, 15, 8, 12, 6]
p = figure(x_range=categories, title="Bar Chart Python Bokeh Example by PratikPathak.com")
p.vbar(x=categories, top=values, width=0.9)
output_notebook()
show(p) 4. Histogram from bokeh.plotting import figure, show, output_notebook
import numpy as np
data = np.random.normal(0, 1, 1000)
p = figure(title="Histogram Python Bokeh Example by PratikPathak.com")
p.hist(data, bins=30, color="navy", alpha=0.5)
output_notebook()
show(p) 5. Pie Chart from bokeh.plotting import figure, show, output_notebook
labels = ["A", "B", "C", "D"]
values = [10, 15, 8, 12]
p = figure(title="Pie Chart Python Bokeh Example by PratikPathak.com")
p.wedge(x=0, y=0, radius=0.4, start_angle=0.6, end_angle=2.6, color=["red", "green", "blue", "yellow"], legend_label=labels)
output_notebook()
show(p) | | Live Preview Source Code 🌿 Contribute 6. Time Series Plot from bokeh.plotting import figure, show, output_notebook
from datetime import datetime, timedelta
start = datetime(2023, 1, 1)
end = start + timedelta(days=30)
x = [start + timedelta(days=i) for i in range((end-start).days)]
y = [10, 15, 8, 12, 6, 18, 9, 14, 7, 11, 5, 16, 8, 13, 6]
p = figure(x_axis_type="datetime", title="Time Series Plot Python Bokeh Example by PratikPathak.com")
p.line(x, y, line_width=2)
output_notebook()
show(p) 7. Linked Brushing from bokeh.plotting import figure, show, output_notebook
from bokeh.models import ColumnDataSource
x1 = [1, 2, 3, 4, 5]
y1 = [4, 5, 5, 7, 3]
x2 = [2, 3, 4, 5, 6]
y2 = [2, 4, 6, 8, 4]
source = ColumnDataSource(data=dict(x1=x1, y1=y1, x2=x2, y2=y2))
p1 = figure(title="Scatter Plot 1")
p1.circle('x1', 'y1', source=source)
p2 = figure(title="Scatter Plot 2 Python Bokeh Example by PratikPathak.com")
p2.circle('x2', 'y2', source=source)
output_notebook()
show(p1, p2) 8. Hover Tooltips from bokeh.plotting import figure, show, output_notebook
from bokeh.models import HoverTool
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 3]
p = figure(title="Hover Tooltips Python Bokeh Example by PratikPathak.com")
p.circle(x, y, size=15, fill_color="navy", line_color="white", alpha=0.5)
hover = HoverTool(tooltips=[("(x,y)", "(@x, @y)")])
p.add_tools(hover)
output_notebook()
show(p) 9. Annotations from bokeh.plotting import figure, show, output_notebook
from bokeh.models import Arrow, VectorRenderer, Label
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 3]
p = figure(title="Annotations Python Bokeh Example by PratikPathak.com")
p.circle(x, y, size=15, fill_color="navy", line_color="white", alpha=0.5)
arrow = Arrow(x_start=2, y_start=4, x_end=3, y_end=5, line_width=2, line_color="red")
label = Label(x=3, y=6, text="This is a label", render_mode='css', border_line_color='black', border_line_alpha=1.0, background_fill_color='white', background_fill_alpha=0.5)
p.add_layout(arrow)
p.add_layout(label)
output_notebook()
show(p) 10. Custom Glyphs from bokeh.plotting import figure, show, output_notebook
from bokeh.models.glyphs import Asterisk
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 3]
p = figure(title="Custom Glyphs Python Bokeh Example by PratikPathak.com")
p.add_glyph(x, y, Asterisk(size=20, line_color="red", fill_color="yellow"))
output_notebook()
show(p) | | Live Preview Source Code 🌿 Contribute 11. Gridlines and Axes from bokeh.plotting import figure, show, output_notebook
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 3]
p = figure(title="Gridlines and Axes Python Bokeh Example by PratikPathak.com", x_range=(0, 6), y_range=(0, 8))
p.grid.grid_line_color = "grey"
p.grid.grid_line_dash = [6, 4]
p.xaxis.axis_label = "X-axis"
p.yaxis.axis_label = "Y-axis"
p.line(x, y, line_width=2)
output_notebook()
show(p) 12. Legend from bokeh.plotting import figure, show, output_notebook
x1 = [1, 2, 3, 4, 5]
y1 = [4, 5, 5, 7, 3]
x2 = [2, 3, 4, 5, 6]
y2 = [2, 4, 6, 8, 4]
p = figure(title="Legend Python Bokeh Example by PratikPathak.com")
p.line(x1, y1, line_width=2, color="red", legend_label="Line 1")
p.line(x2, y2, line_width=2, color="blue", legend_label="Line 2")
p.legend.location = "top_left"
output_notebook()
show(p) 13. Categorical Plots from bokeh.plotting import figure, show, output_notebook
fruits = ["Apples", "Pears", "Nectarines", "Plums", "Grapes", "Strawberries"]
counts = [5, 3, 4, 2, 4, 6]
p = figure(x_range=fruits, title="Categorical Plots Python Bokeh Example by PratikPathak.com")
p.vbar(x=fruits, top=counts, width=0.9)
p.xaxis.axis_label = "Fruit"
p.yaxis.axis_label = "Count"
p.xaxis.axis_label_text_font_size = "12pt"
p.yaxis.axis_label_text_font_size = "12pt"
output_notebook()
show(p) 14. Subplots from bokeh.plotting import figure, show, output_notebook
from bokeh.layouts import gridplot
x1 = [1, 2, 3, 4, 5]
y1 = [4, 5, 5, 7, 3]
x2 = [2, 3, 4, 5, 6]
y2 = [2, 4, 6, 8, 4]
p1 = figure(title="Scatter Plot 1 Python Bokeh Example by PratikPathak.com")
p1.circle(x1, y1, size=10, color="navy", alpha=0.5)
p2 = figure(title="Scatter Plot 2 Python Bokeh Example by PratikPathak.com")
p2.circle(x2, y2, size=10, color="red", alpha=0.5)
grid = gridplot([[p1, p2]], plot_width=400, plot_height=400)
output_notebook()
show(grid) 15. Interactive Plots from bokeh.plotting import figure, show, output_notebook
from bokeh.models import ColumnDataSource, HoverTool, BoxSelectTool
import numpy as np
x = np.random.random(1000)
y = np.random.random(1000)
source = ColumnDataSource(data=dict(x=x, y=y))
p = figure(title="Interactive Plots Python Bokeh Example by PratikPathak.com", tools="hover,box_select")
p.circle('x', 'y', source=source, size=3, color="navy", alpha=0.5)
hover = HoverTool(tooltips=[("(x,y)", "(@x, @y)")])
p.add_tools(hover)
output_notebook()
show(p) | | Live Preview Source Code 🌿 Contribute 16. Linked Panning and Zooming from bokeh.plotting import figure, show, output_notebook
from bokeh.models import Range1d
x1 = [1, 2, 3, 4, 5]
y1 = [4, 5, 5, 7, 3]
x2 = [2, 3, 4, 5, 6]
y2 = [2, 4, 6, 8, 4]
p1 = figure(title="Scatter Plot 1 Python Bokeh Example by PratikPathak.com", x_range=Range1d(0, 6), y_range=Range1d(0, 8))
p1.circle(x1, y1, size=10, color="navy", alpha=0.5)
p2 = figure(title="Scatter Plot 2 Python Bokeh Example by PratikPathak.com", x_range=p1.x_range, y_range=p1.y_range)
p2.circle(x2, y2, size=10, color="red", alpha=0.5)
output_notebook()
show(p1, p2) 17. Linked Axis Ranges from bokeh.plotting import figure, show, output_notebook
from bokeh.models import Range1d
x1 = [1, 2, 3, 4, 5]
y1 = [4, 5, 5, 7, 3]
x2 = [2, 3, 4, 5, 6]
y2 = [2, 4, 6, 8, 4]
p1 = figure(title="Scatter Plot 1", x_range=(0, 6), y_range=(0, 8))
p1.circle(x1, y1, size=10, color="navy", alpha=0.5)
p2 = figure(title="Scatter Plot 2", x_range=p1.x_range, y_range=p1.y_range)
p2.circle(x2, y2, size=10, color="red", alpha=0.5)
output_notebook()
show(p1, p2) 18. DateTime Axis from bokeh.plotting import figure, show, output_notebook
from datetime import datetime, timedelta
start = datetime(2023, 1, 1)
end = start + timedelta(days=30)
x = [start + timedelta(days=i) for i in range((end-start).days)]
y = [10, 15, 8, 12, 6, 18, 9, 14, 7, 11, 5, 16, 8, 13, 6]
p = figure(x_axis_type="datetime", title="Datetime Axis Python Bokeh Example by PratikPathak.com")
p.line(x, y, line_width=2)
output_notebook()
show(p) 19. Heatmap from bokeh.plotting import figure, show, output_notebook
import numpy as np
data = np.random.rand(10, 10)
p = figure(title="Heatmap Python Bokeh Example by PratikPathak.com")
p.image(image=[data], x=0, y=0, dw=10, dh=10, palette="Viridis256")
output_notebook()
show(p) 20. Streamgraph from bokeh.plotting import figure, show, output_notebook
from bokeh.models import ColumnDataSource
import numpy as np
# Generate some sample data
x = np.linspace(0, 10, 100)
y1 = np.cumsum(np.random.randn(100))
y2 = np.cumsum(np.random.randn(100))
y3 = np.cumsum(np.random.randn(100))
y4 = np.cumsum(np.random.randn(100))
y5 = np.cumsum(np.random.randn(100))
source = ColumnDataSource(data=dict(x=x, y1=y1, y2=y2, y3=y3, y4=y4, y5=y5))
p = figure(title="Streamgraph Python Bokeh Example by PratikPathak.com")
p.area(x='x', y1='y1', y2='y2', y3='y3', y4='y4', y5='y5', source=source, line_color=None)
output_notebook()
show(p) | | Live Preview Source Code 🌿 Contribute 21. Polar Plot from bokeh.plotting import figure, show, output_notebook
import numpy as np
r = np.linspace(0.1, 1, 10)
theta = np.linspace(0, 2*np.pi, 10)
p = figure(title="Polar Plot Python Bokeh Example by PratikPathak.com", plot_width=600, plot_height=600, x_range=(-1.2, 1.2), y_range=(-1.2, 1.2), toolbar_location=None)
p.polar(r, theta, color="navy", alpha=0.5, line_width=2)
output_notebook()
show(p) 22. Donut Chart from bokeh.plotting import figure, show, output_notebook
from bokeh.models import ColumnDataSource
labels = ["A", "B", "C", "D"]
values = [10, 15, 8, 12]
source = ColumnDataSource(data=dict(labels=labels, values=values))
p = figure(title="Donut Chart Python Bokeh Example by PratikPathak.com", x_range=labels)
p.wedge(x=0, y=1, radius=0.4, start_angle=0.6, end_angle=2.6, color=["red", "green", "blue", "yellow"], legend_field="labels")
p.wedge(x=0, y=1, inner_radius=0.3, outer_radius=0.4, start_angle=0.6, end_angle=2.6, color="white")
p.axis.visible = False
p.grid.grid_line_color = None
output_notebook()
show(p) 23. Treemap from bokeh.plotting import figure, show, output_notebook
from bokeh.models import TreemapRenderer, ColumnDataSource
import pandas as pd

# Sample data
data = pd.DataFrame({
    'label': ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'],
    'parent': ['', 'A', 'A', 'B', 'B', 'C', 'C', 'D'],
    'value': [10, 5, 4, 3, 2, 1, 1, 1]
})

source = ColumnDataSource(data)
p = figure(title="Treemap Python Bokeh Example by PratikPathak.com")
treemap = TreemapRenderer(
    source=source,
    label='label',
    parent='parent',
    value='value',
    color_discrete_sequence=["#e6550d", "#3182bd", "#31a354", "#756bb1", "#636363", "#9e9ac8", "#de2d26", "#fd8d3c"],
)
p.add_layout(treemap)
output_notebook()
show(p) If you get any error, make sure you have installed Python pandas by using the “pip install pandas” command 24. Network Plot from bokeh.plotting import figure, show, output_notebook
from bokeh.models import ColumnDataSource, HoverTool, NodesAndLinkedEdges
import networkx as nx

# Sample data
nodes = ['A', 'B', 'C', 'D', 'E', 'F']
edges = [('A', 'B'), ('A', 'C'), ('B', 'D'), ('B', 'E'), ('C', 'F')]
G = nx.Graph()
G.add_nodes_from(nodes)
G.add_edges_from(edges)

node_positions = nx.spring_layout(G)
node_x = [node_positions[node][0] for node in G.nodes()]
node_y = [node_positions[node][1] for node in G.nodes()]
node_color = ['red', 'green', 'blue', 'yellow', 'purple', 'orange']

source = ColumnDataSource(data=dict(
    x=node_x,
    y=node_y,
    color=node_color,
    node=nodes
))

p = figure(title="Network Plot Python Bokeh Example by PratikPathak.com", x_range=(-1.1, 1.1), y_range=(-1.1, 1.1))
p.add_tools(HoverTool(tooltips=[("Node", "@node")]))
p.circle('x', 'y', size=15, color='color', source=source)

edge_x = []
edge_y = []
for start, end in edges:
    x0, y0 = node_positions[start]
    x1, y1 = node_positions[end]
    edge_x.append(x0)
    edge_x.append(x1)
    edge_x.append(None)
    edge_y.append(y0)
    edge_y.append(y1)
    edge_y.append(None)

p.multi_line(edge_x, edge_y, color="black", alpha=0.5, line_width=1)

output_notebook()
show(p) 25. Sankey Diagram from bokeh.plotting import figure, show, output_notebook
from bokeh.models import Sankey, ColumnDataSource

# Sample data
flows = [
    ('A', 'X', 5),
    ('B', 'X', 3),
    ('A', 'Y', 2),
    ('B', 'Y', 4),
    ('X', 'C', 4),
    ('X', 'D', 3),
    ('Y', 'C', 2),
    ('Y', 'D', 4)
]

source = ColumnDataSource(data=dict(
    source=[flow[0] for flow in flows],
    target=[flow[1] for flow in flows],
    value=[flow[2] for flow in flows]
))

p = figure(plot_width=800, plot_height=400, title="Sankey Diagram Python Bokeh Example by PratikPathak.com")
sankey = Sankey(source=source, label_text_color="white", label_text_font_size="8pt")
p.renderers.append(sankey)

output_notebook()
show(p) | | Live Preview Source Code 🌿 Contribute 26. Chord Diagram from bokeh.plotting import figure, show, output_notebook
from bokeh.models import ColumnDataSource, CategoricalColorMapper
import numpy as np

# Sample data
nodes = ['A', 'B', 'C', 'D', 'E', 'F']
connections = [
    ('A', 'B', 0.5), ('A', 'C', 0.3), ('A', 'D', 0.2),
    ('B', 'C', 0.4), ('B', 'D', 0.3), ('B', 'E', 0.3),
    ('C', 'D', 0.2), ('C', 'E', 0.3), ('C', 'F', 0.5),
    ('D', 'E', 0.2), ('D', 'F', 0.3), ('E', 'F', 0.4)
]

source = ColumnDataSource(data=dict(
    start=np.array([con[0] for con in connections]),
    end=np.array([con[1] for con in connections]),
    value=np.array([con[2] for con in connections])
))

p = figure(title="Chord Diagram Python Bokeh Example by PratikPathak.com", plot_width=800, plot_height=800)
chord = p.chord(
    source=source, 
    start_angle=np.pi / 2,
    direction="clockwise",
    colors=CategoricalColorMapper(factors=nodes, palette="Spectral11")
)

output_notebook()
show(p) How to Contribute? Feel free to open a PR request on our GitHub repo. Steps to contribute: Fork the repo Make changes in the Forked repo and save Open a Pull Request That’s it 😄! 🌿 Contribute Conclusion In this Repo, I have shared 25+ Python Bokeh examples that can help you learn Python Bokeh. Feel free to contribute to our GitHub repo and keep it updated. Also published . here

Getting Started With Python Bokeh: 25+ Data Visualization Examples With Source Code

is the study of prosperous, harmonious, and equitable societies, often depicted in fiction. These societies imagined in fiction can represent ideal or aspirational models of social, economic, and environmental organization, where resources are used sustainably and equitably, and where there is a positive interconnection between humans and the environment. Prospenomics may involve analyzing these fictional models to extract insights and inspiration for building a real society that is fairer and more prosperous. Prospenomics On the other hand, the concept of refers to a future stage where the scarcity of material resources is no longer a predominant concern. In this stage, advanced technology, production efficiency, and sustainable resource use would allow for an abundance of goods and services for all, without compromising the environment or depleting natural resources. Post-scarcity implies a fundamental shift in how society organizes and utilizes its resources, seeking to achieve a sustainable balance between human needs and planetary preservation. Post-Scarcity Prospenomics, also known as Prospenomia, is the study of prosperity and its generators, aiming to pave a path towards Post-Scarcity. Through an economic and social approach that transcends the conventional paradigms of known economic theory, which often associates relatively low abundance with hard and inefficient work and fails to distribute well-being among individuals, paying little attention to the depletion of resources on the planet. The field of Prospenomics arises from the urgent need to rethink current economic and social models. To achieve this, we must study all known forms of prosperity, from intelligent decisions made in ancient times to the fiction of Gene Roddenberry's Star Trek, envisioning a future where prosperity is abundant, where we no longer use monetary fractions for the exchange of goods and services, and people work to satisfy their talents and ambitions for personal upliftment; or also the ideas of Buckminster Fuller, in which prosperity was not limited solely to the accumulation of material wealth or economic growth but rather ensuring well-being and sustainability for all forms of life on the planet. Considering the 4.5 billion years of evolution and extinctions that have shaped our planet, the delicate balances of biological relationships that have brought us to today, Prospenomics recognizes the complexity of interactions between living beings and the environment, as well as the central role of human beings in this context, as intellectual protagonists of the planet. Therefore, we must make use of our cerebral cortex, the most evolved tool that nature has ever created, as well as future forms of Artificial Intelligence to better explore the resources "seemingly" scarce, to the point of recognizing that they are extremely more abundant than conceived. Throughout history, humanity has emerged as a species capable of profoundly transforming the environment and influencing the fate of other life forms. This unique ability confers significant responsibility on human beings in preserving and balancing the global ecosystem. Prospenomics starts from the assumption that the current environmental and social crisis is the result of an economic model based on profit maximization and rampant consumption, which ignores the planet's limits and generates extreme inequality. In this sense, the study seeks to identify and promote alternative economic principles that can lead to a more sustainable and prosperous society. In 1986, I had an unusual class, "Brazilian Problem Studies",  that my mentor, Antonio Sérgio Pacheco Mercier, taught. Even though they were on Saturdays, I loved attending his classes. Professor Mercier had the gift of captivating students with his engaging narratives, especially when discussing subjects like international trade. His classes were rich; he talked about a convention in Luang Prapang, which inspired my friend Gilberto Lacerda to adopt a new dream tourist destination, or the international maritime law agreement signed in Montego Bay, Jamaica, in 1982 - he took us on a journey to these incredible locations. The professor showed us the importance of these events, as well as the pleasures of practicing a profession that best suits one's spirit, reconciling the joy of travel with improving human relations on the planet. However, it was during a conversation about possible topics for my thesis that Professor Mercier truly inspired me. I shared with him my supposedly "revolutionary" idea of applying science fiction concepts to economics and public administration, an approach I called #prospenomics. I believed (and still believe) that just as the science fiction of inspired Santos-Dumont in multiple inventions, we could also use Gene Roddenberry's post-scarcity society from Star Trek as inspiration for new approaches in economics and public administration. Jules Verne The globe with Africa on the right - the origin of humanity, goes counterclockwise to North America with more distant parallel lines and finally South America, in white. The idea is that, in a counter-clockwise spiral that begins in Africa, the further we move away from our origins, the more we lose self-knowledge and the globe becomes increasingly devoid of its original and natural lines. The drawing conveys the idea that, if a Cartesian analysis of the planet were carried out, we would understand it better and return to a greater balance, similar to that of the first hominids - Osasco 1986 At first, Professor Mercier was interested in the argument, but after listening carefully to my explanations, he said that my ideas were "still in their infancy" and that there was "little applicability to reality." :( However, he encouraged me to study more about the subject and to explore these ideas further. Even though I felt a little frustrated for being so far from a viable argument, with his careful guidance and constructive criticism, I embarked on a journey of research and reflection that broadened my academic and professional horizons, achieving feats that I had never dreamed of achieving. The End of Working for a Living and the Beginning of Working for Your Talents As we move towards a future where traditional notions of scarcity and work are being questioned, there is a need to explore new approaches to societal and economic organization. In this context, digital tools like , for instance, have played a significant role in facilitating connections between people and job opportunities, aiming to enable individuals to work based on their talents and passions, rather than just to sustain their basic needs. LinkedIn The underlying idea behind the use of LinkedIn and other similar tools is that by creating opportunities for people to work based on their talents and interests, rather than just to earn a living, it is possible to promote a more creative, productive, and fulfilling society for all its members. This approach, known as "working for talent," aims to maximize the potential of each individual, encouraging creative expression, innovation, and personal and professional growth. How Prospenomics Differs from Simple Economics If an economy traditionally focuses on the exchange of wealth among humans, it differs exponentially from prospenomics, which focuses on the relationships between prosperity and the ecological balance of the planet as a whole. While the economy traditionally focuses on monetary aspects and the distribution of resources among humans, prospenomics broadens this perspective to consider global prosperity, in which the life of any living being, no matter how insignificant it may seem to humans, if negatively affected, will adversely affect the well-being of all life forms and the sustainability of the planet. "While Economics operates in a monophonic mode, focusing on the exchange of wealth within human relationships, Prospenomics operates in a stereophonic mode, considering the broader scope of prosperity and ecological balance across the planet.

Prospenomics: Redefining Prosperity and Work in a Post-Scarcity Era

প্রসপেনোমিক্স: অভাব-পরবর্তী যুগে সমৃদ্ধি এবং কাজকে পুনরায় সংজ্ঞায়িত করা

Prospenomics: Wohlstand und Arbeit in einer Zeit nach der Knappheit neu definieren

Prospenomía: redefiniendo la prosperidad y el trabajo en una era posterior a la escasez

Prospenomics : redéfinir la prospérité et le travail à l’ère de l’après-pénurie

प्रोस्पेनोमिक्स: अभाव-पश्चात युग में समृद्धि और कार्य को पुनर्परिभाषित करना

プロスペノミクス: ポスト・スカーシティ時代における繁栄と仕事の再定義

프로스페노믹스: 결핍 이후 시대의 번영과 일자리를 재정의하다

Prospenomia: redefinindo a prosperidade e o trabalho em uma era pós-escassez

Проспеномика: новое определение процветания и труда в эпоху постдефицита

Prospenomik: Kıtlık Sonrası Bir Dönemde Refahı ve Çalışmayı Yeniden Tanımlamak

Prospenomics: Xác định lại sự thịnh vượng và công việc trong kỷ nguyên hậu khan hiếm

繁荣经济学：重新定义后稀缺时代的繁荣与工作

Cassandra is a distributed, decentralized, scalable, and highly available wide-column database. In terms of CAP theorem, Cassandra stands for AP (availability and partition tolerance). It means that Cassandra prefers that all clients can find data even in cases where not all nodes are available and will work as expected when partial network failure occurs. However, it also means that the consistency of the data can be compromised in favor of availability and partition tolerance - users will see the data, but it may be stale for a while. Cassandra is designed for achieving high throughput and faster write operations. And it is precisely sacrificing consistency that allows Cassandra to be highly available. By default, Cassandra is designed to be eventually consistent, meaning that it may not provide strong consistency. This makes Cassandra suitable for applications where consistency is not a critical requirement. However, it is possible to configure Cassandra to provide strong consistency, although this can impact performance. Cassandra, being a NoSQL database, does not support table joins, foreign keys, or the ability to add columns other than the primary key in the WHERE clause while querying. These limitations should be taken into consideration before choosing to use Cassandra. Cassandra Building blocks : A column represents a key-value pair and serves as the fundamental unit of data structure. Column : acts as a container for columns that are referenced by the primary key. Row : serves as a container for tables that span across one or more Cassandra nodes. Keyspace : a container of keyspaces within Cassandra. Cluster : refers to a computer system that runs an instance of Cassandra. A node can be a physical host, a machine instance in the cloud, or even a Docker container. Node How Cassandra stores data Cassandra stores the data as a column family. It serves as a container for columns that are referenced by a primary key. A row of a column family includes several columns with key and value, and the row key serves as the primary key: A column family can store a different set of columns for each row key: Cassandra does not store columns with null values, which helps save significant storage space What is the primary key in Cassandra? The uniquely identifies each row of a table. In Cassandra, the primary key has two parts: Primary key In Cassandra, the partition key determines which node stores the data, while the clustering key determines how the data is stored within a node. For instance, consider a table with a . This primary key consists of two parts, represented by the two columns: PRIMARY KEY (city_id, event_id) 1. serves as the partition key, meaning that data will be partitioned based on the field, resulting in all rows with the same being stored on the same node. city_id city_id city_id 2. acts as the clustering key. Within each node, the data is organized and stored in sorted order based on the column. event_id event_id Clustering keys determine the storage arrangement of data within a node. It is possible to have multiple clustering keys, and any columns listed after the partition key are referred to as clustering columns. Clustering columns define the order in which data is organized on a node. Every row with partition key = "Paris" will be stored on the same node, ordered by the value of the event_id column. Data partitioning out of the box Cassandra provides data partitioning based on to reduce latency in read/write operations and increase the throughput of the system when the amount of data stored in the database becomes large. Consistent Hashing The in Cassandra is responsible for deciding how data is distributed across the Consistent Hash ring. When data is inserted into a Cassandra cluster, the partitioner applies a hashing algorithm to the . The result of this hashing algorithm determines the range in which the data falls and determines the node on which the data will be stored. partitioner partition key Coordinator node In Cassandra, each node is aware of the token assignments of other nodes through , allowing any node to handle requests for any other node's range. Therefore, a client can connect to any node to initiate read or write queries. gossip protocol The node that receives the request is known as the and can be any node in the cluster. If a key does not belong to the coordinator's range, the request is forwarded to the replicas responsible for that range. coordinator Replication Cassandra replicates data across multiple nodes to ensure high availability. Each node in Cassandra serves as a replica for a specific data range. By spreading multiple copies of the data across different replicas, Cassandra enables other replicas to handle queries for that data range in case one node is unavailable. Two settings will affect the replication process: The replication factor determines how many nodes will store copies of the same data. In a cluster with a replication factor of 3, each row will be stored on three different nodes. Each keyspace in Cassandra can have a different replication factor. In Cassandra, the first replica is assigned to the node that owns the range based on the hash of the partition key. The remaining replicas are then placed on consecutive nodes in a clockwise manner. Cassandra uses two replication strategies to determine which nodes will be responsible for the replicas: Simple replication strategy In this strategy, the first replica is placed on a node determined by the partitioner, and the succeeding replicas are placed on the subsequent nodes in a clockwise manner. This replication strategy is applicable only for a single data center cluster. Network topology strategy To ensure resilience against complete loss of data, additional replicas within the same data center are placed by moving clockwise along the ring until reaching the first node in a different data center. This arrangement helps mitigate the impact of simultaneous failures that typically occur within the same data center due to power, cooling, or network issues. When it comes to multi-datacenter configurations, you should consider the network topology strategy. This approach allows for the specification of varying replication factors for each data center, enabling control over the number of replicas to be placed in each specific location. When to use Cassandra Cassandra excels in applications that require handling large volumes of data and prioritize data availability over consistency. : It is well-suited for 1. : Cassandra is an ideal choice for IoT environments, as it can handle massive amounts of data generated by devices and sensors. Its distributed architecture enables management of geographically dispersed, large-scale data. Internet of Things (IoT) Applications 2. : Applications dealing with time-series data, such as metrics, monitoring systems, and telemetry data, benefit from Cassandra's efficient write operations and horizontal scalability. These capabilities are crucial for storing and managing extensive volumes of time-stamped data. Time-Series Data 3. : Cassandra offers high throughput and low-latency data access, making it suitable for web and mobile platforms with large user bases generating significant amounts of data. This includes social media platforms, gaming apps, and e-commerce sites. Web and Mobile Applications 4. : Cassandra supports real-time processing of big data, making it a valuable choice for applications requiring immediate insights from large datasets. Examples include recommendation engines and fraud detection systems. Real-Time Big Data Analytics 5. : Enterprises with large, distributed datasets can leverage Cassandra as a data warehouse solution. Its ability to replicate data across multiple data centers ensures high availability and disaster recovery. Distributed Data Warehouses 6. : Cassandra's high write and read throughput makes it well-suited for messaging systems that handle high data volumes, such as event logging, audit trails, or message queues. Messaging Systems 7. : Applications requiring personalized content delivery at scale, such as content management systems, benefit from Cassandra's speed and scalability in delivering customized content to a large number of users simultaneously. Personalization and Content Management Systems 8. : Cassandra's support for multiple data centers makes it an excellent choice for applications requiring geographically distributed data. It ensures low-latency data access across different regions and provides high resilience. Geographically Distributed Applications When not to use Cassandra While Apache Cassandra is powerful and scalable, it may not be suitable for every application or use case. It is less suitable for transaction-heavy applications, complex querying, and scenarios that require strong consistency or rapid schema changes. Traditional relational database management systems (RDBMS) or other NoSQL solutions may be more appropriate in such cases. Here are several scenarios where Cassandra might : not be the optimal choice : Cassandra's complexity and resource requirements can be excessive for small-scale projects or applications with limited datasets. Simpler database solutions may offer a more cost-effective and manageable alternative. Small-Scale Projects : Cassandra does not fully support ACID (Atomicity, Consistency, Isolation, Durability) properties. If your application requires complex transactions typically found in banking or financial systems, a traditional RDBMS might be a better fit. Transactional Systems Requiring ACID Properties : If your application heavily relies on joins, subqueries, or complex aggregations, Cassandra may not be the most suitable choice. It is designed for fast writes and reads but not for complex query processing. Join Heavy Queries and Aggregations : Cassandra provides eventual consistency, which may not be suitable for use cases that require strong consistency for every read and write operation. Data with Strong Consistency Requirements : While Cassandra performs well in multi-node distributed environments, it may not be the optimal choice for single-node or small cluster deployments that require low-latency reads and writes. Low-Latency Reads and Writes in a Single Cluster : Cassandra is not optimized for storing large binary objects (blobs) such as images or videos. Other storage solutions are better suited for efficiently handling large blobs. Blob Storage : Cassandra's query capabilities are limited compared to full-fledged SQL databases. It is not well-suited for applications that heavily rely on ad-hoc querying and reporting. Applications Requiring Ad-hoc Querying In Cassandra, the design of tables is closely connected to the way data will be accessed, emphasizing the query patterns rather than solely focusing on the relationships between data entities. This differs from the approach in RDBMS, where schema design is based on normalization principles. : If your application requires frequent changes to the database schema, Cassandra's schema management may be less flexible compared to traditional RDBMS systems or other NoSQL solutions. Rapid Schema Evolution : While Cassandra is well-suited for write-heavy workloads and real-time data access, it may not be the most suitable choice for data warehousing scenarios that require complex queries, joins, and historical data analysis. Data Warehouse Applications that involve complex queries, joins, and historical data analysis Summary This article provides an overview of Cassandra, a highly scalable and distributed wide-column database. Cassandra is designed to prioritize availability and partition tolerance, making it suitable for applications where consistency is not a critical requirement. It supports high throughput and faster write operations. The building blocks of Cassandra include columns, rows, keyspaces, clusters, and nodes. Columns represent key-value pairs, rows act as containers for columns referenced by the primary key, keyspaces serve as containers for tables spanning multiple nodes, clusters contain keyspaces, and nodes refer to computer systems running Cassandra instances. Cassandra stores data in column families, which are containers for columns referenced by a primary key. Data partitioning is achieved through consistent hashing, allowing for reduced latency and increased throughput. The partitioner distributes data across the Consistent Hash ring, and a coordinator node handles read and write queries. Cassandra provides replication for high availability. Replicas of data are stored on multiple nodes, ensuring that queries can be handled by replicas if a node becomes unavailable. Replication factors and strategies determine the number of replicas and the nodes responsible for them. While Cassandra offers benefits such as scalability and high availability, it has limitations. It does not support table joins, foreign keys, or the ability to add columns other than the primary key in the WHERE clause during querying. Overall, Cassandra is a powerful database solution for highly scalable applications, particularly those that prioritize availability and partition tolerance over strong consistency. There are several interesting aspects of Cassandra that I will cover in my next article. so you don't miss it! Subscribe to me Cheers!

Cassandra: Highly Scalable Database Out of the Box

ক্যাসান্ড্রা: বাক্সের বাইরে উচ্চ মাত্রার ডেটাবেস

Cassandra: Hochskalierbare Datenbank sofort einsatzbereit

Cassandra: base de datos altamente escalable lista para usar

Cassandra : base de données hautement évolutive prête à l'emploi

कैसेंड्रा: बॉक्स से बाहर अत्यधिक स्केलेबल डेटाबेस

Cassandra: すぐに使える拡張性の高いデータベース

Cassandra: 즉시 사용 가능한 확장성이 뛰어난 데이터베이스

Cassandra: banco de dados altamente escalável pronto para uso

Cassandra: масштабируемая база данных «из коробки»

Cassandra: Kullanıma Hazır Yüksek Derecede Ölçeklenebilir Veritabanı

Cassandra: Cơ sở dữ liệu có khả năng mở rộng cao ngay lập tức

Cassandra：开箱即用的高度可扩展数据库

Let's learn about via these 62 free stories. They are ordered by most time reading created on HackerNoon. Visit the to find the most read stories about any technology. Tech Startups /Learn Repo 1. Unicorn Startup Companies Founded During a Recession The global recession is a turbulence time for all businesses. We have used to be afraid of scenarios that may play out during and after the financial downturn. Different sources define this period as "a significant decline in economic activity, lasting more than a few months, normally visible in the real gross domestic product (GDP), real income, employment, industrial production, and wholesale-retail sales." 2. Clubhouse: The Bomani Effect Clubhouse is an invitation-only, audio chat app, valued in Dec 2020 at $100 million. It is now valued at 1 billion USD since Jan 2021. 3. What Makes A Venture Studio So Successful at Building Startups? As an increasing number of venture studios break into the entrepreneurial scene, it’s time to analyze what makes this model so competitive. 4. A Genius, a Deceiver, or a Naive Dreamer? Deep Tech Explained In 1943, the American aircraft engineer Clarence "Kelly" Johnson received a call from the Pentagon: the US Air Force needed a fighter jet. Johnson ran Advanced Development Projects (ADP), a closed division of the Lockheed Corporation aircraft manufacturing company. It was located in a separate room, and only employees directly involved in the development of ADP could go in there. 5. D2C 101: Why the Future of Retail is Vertical Commerce and D2C Brands For as long as humanity has existed, so has commerce in the form of sharing, bartering and selling resources. Even before currency in its most rudimentary form has come into existence in Mesopotamia in 3000BC, economies were created through bartering where people would exchange goods/services based on perceived value (Person A would want to sell Item A to Person B who finds Item A valuable in return for Item B which holds more value to Person A than it does to Person B). 6. How to Launch a Successful Startup and Keep it Blooming: 25 Great Tips Learn to think critically about your ideas 7. Low-code for Hackers In recent years Low-code/No-code has become a hot topic. According to that approach an IT-system is developed visually. Conventional wisdom says that building an MVP on low-code is OK, but if something sophisticated and scalable is needed, you have to code it traditionally. These visual tools seem to be very limited. Let me reveal the other side of low-code world, which has no such limits. 8. An insight into Asia's Tech Startup Scene With the boom in technology, tech startups are booming all over the world, especially in the Asian region. In recent years, it has been noticed that startups are growing the track record of success stories in the business world. 9. Why Working in a Startup Is More Rewarding Than a Career in Big-Tech Five reasons of why working in a startup might be more rewarding than position in a big-name company for specialists, who are focused on career achievements. 10. Start with a Prototype, Follow with an MVP and Then Get to the Final Product Your Guide to the Main Stages of Tech Startup Development 11. The Pitch Deck That Makes Investors Say Yes In these uncertain times of Covid-19 and lockdown, it’ll come as no surprise to say that investments, as with everything else, have taken a bit of a hit. In France alone, investment was down 30% in April compared to April 2019. But, not to despair! Despite the current climate, investors are indeed still active. 12. #FoundersConnect: Njoku Emmanuel, the 19-year-old CEO & Co-founder of Lazerpay Interview with Lazerpay co-founder & CEO, Njoku Emmanuel. 13. So You're Planning To Pitch Your Startup W/O a Growth Strategy This Year? A month ago, I had the privilege to chat with a third-time founder with two successful exits under his belt. 14. Valuing Cryptocurrencies: When to Go by Exchange Listing Count and When Not To At the moment, there are more than 1500 cryptocurrencies existing today, with a combined market capitalization of over $18 billion. As the crypto industry progresses at a high pace, investors are constantly willing to trade in this never-sleeping market. In order to be able to participate in cryptocurrency trading, users turn to the so-called exchanges. 15. Why Startups Are Better To Work For Last fall as I started my last year at UCLA, I aggressively applied and interviewed for programming jobs. The decision agonized me for weeks and I devoured career guides and advice. And in the end, I chose a small 50 person startup over exciting companies like Facebook, Stripe, and Cruise. I basically chose less money for more work mostly because it was a startup. 16. Should You Build Your Startup in Public? You have had a great idea, spent some time validating your business idea and are now facing the next questions: How should I approach my building? One of the most used buzzwords in the indie hacker space is “building in public“. It comes in different styles and with different methods. Of course, success in building a side-project publicly also varies. I aim to provide a starting point in this article with a look at methods, platforms, and tools. This blog-post links into the series on introduction in the indie hacker space. 17. Using CI/CD Pipelines to Increase the Speed and Quality of Software Development Continuous Integration & Continuous Delivery in the development process. How the CI/CD pipeline helps create products and implement new features better and fast 18. Startup Interview with Changsu Lee, Allganize's Founder and CEO This interview with Changsu Lee, founder and CEO of Allganize, Inc. goes into details the main reasons why he started his AI NLU company back in 2017. 19. Ayo Akindele, Founder and CEO of Kyshi Interview with Ayo Akindele, of Kyshi, a payment startup for transnational money transactions. 20. Startup Interview with Vivek Khatri, Director & Founder, at Emizen Tech Vivek Khatri, Director and Founder of a Startup of the year nominee Emizen Tech, shares their origin story, why they focus on retention and exciting technology. 21. #FoundersConnect: Koromone Koroye, Managing Editor of TechCabal Conversation with Koromone Koroye, Managing Editor of TechCabal on her interesting life experiences, thoughts of religion, work culture and more! 22. 3 Ways in Which Launching a Startup Is Easier in the Post-COVID Era The post-COVID world is full of global opportunities for early-stage companies to develop and grow. Learn how to build a startup with online tools. 23. #FoundersConnect: Eyitayo Ogunmola, Founder of Utiva, an African Ed-tech Startup I speak with Eyitayo Ogunmola, the CEO of Utiva, an education service for Africans and people of colour entering the tech industry. 24. 5 Productivity Hacks to Get More Done as the Founder of a Startup As a founder of a startup, chances are that you have one thing constantly going on in your mind: getting more work done. 25. How Do You Measure Success? Downloads, Traction, and Revenue MyValet updates car parking and car services to the 21st century. No more paper, no more stamps, no more cash. 26. How to Evaluate New Ideas For Value? It is easy to know the value of a product or service which is used often and is accepted as something worthy to pay for. Everyone agrees gold coins are valuable even if they don’t know the current gold rate in their currency. 27. As the Hype Ends, Brazil's Tech Startup Investment Landscape is Changing for the Better Brazil's become a startup paradise, but the current funding low is leaving its mark. What's in store for the Brazilian startup ecosystem at the end of 2022 28. 5 Challenges Your Cannabis Tech Startup Needs to Solve: 2020 Edition With recreational and medical marijuana legalisation efforts comes great business opportunity, and unsolved problems. As of today, recreational and medical marijuana legalisation efforts have succeeded in multiple jurisdictions across the world, and counting. On the list is Luxembourg to become the first European country to  join the ranks of Canada and U.S. in relaxing weed laws. 29. #FoundersConnect: Bunmi Akinyemiju, Partner at GreenHouse Capital, Former CEO Venture Garden Group I speak with Bunmi Akinyemiju, one of the biggest investors in the African startup space, and Founding Partner at GreenHouse Capital. 30. The 3-Step Process to Hiring a Software Engineer For Your Startup The standard coding interview gauges coding prowess the same way an IQ test gauges intelligence. Basically, barely at all. 31. The Series A Startup Guide to Outstaffing Software Developers This is a quick guide on how to select remote development teams for startups at the Series A stage that may need to add remote engineers to their teams. 32. #FoundersConnect: Ameyaw Debrah, the Founder of Ameyawdebrah.com | Ghanaian Celebrity Blogger Peace has a conversation with Ameyaw Debrah, Ghanaian celebrity blogger and founder of Ameyawdebrah.com, a lifestyle news blog about media, his life, and more. 33. Growing a Startup is all About Decision Making I love reading the insights of successful entrepreneurs contemplating on their decision-making evolution and try to draw insights from my own experience as a startup owner. The more I’m into it, the more I realize that growing a startup is all about decision making. 34. #FoundersConnect: Tosin Faniro-Dada, MD /CEO of Endeavor (Nigeria) Peace has a conversation with Tosin Faniro-Dada, the MD & CEO of Endeavor in Nigeria, about her career and her passion for helping entrepreneurs. 35. #FoundersConnect: Ben Lyon, CEO and CoFounder of Stax, an Offline Payment App for Africans Conversation with Ben Lyon of Hover Developer Services, the parent company of Stax, a simple way to carry out payment services without internet or USSD codes. 36. Meet Clockwise Software Meet Clockwise Software - a Ukrainian JavaScript development company with a head office in Dnipro. 37. [ANN] Pitch.Tech - A Dottech Domains & Startup Grind Competition For Ideapreneurs Win $10,000 in equity-free funding and over $100,000 in startup benefits. 38. Kristina Cahojova, CEO at Kegg.Tech: #MyStartInTech Story In this interview, Kristina Cahojova, CEO of Kegg.Tech talks about how she got her start in the tech world. 39. All the Tech You Need to Start an Online Business New business owners must ensure they have a good foundation of the necessary technologies to run their businesses. 40. What is the Difference Between MVP and POC? In this article, we will look at definitions for MVPs and POCs and the circumstances in which to use them. 41. Tadeas Adamjak from UXtweak Talks About How to "Make Your Websites Better" UXtweak is user experience (UX) research platform providing tools for usability testing, IA research and behavior analysis. Read its origin story and more! 42. Thrilled to be Recognized as a Trending Startup in Jaipur, India Emizentech is recognized as one of the trending startups in Jaipur India in 2022 by Hackernoon. 43. Should I Work At A Startup Or An Established Company? A Company vs A Startup. What’s best? In this article, I review my experience working at both startups and companies to help you determine your best route. 44. #FoundersConnect: Godwin Tom, Serial Entrepreneur, Music Business Mogul & CEO of iMANAGE AFRICA Conversation with Godwin Tom, an expert in music management and CEO of iMANAGE Africa on his journey, his work, and the future. 45. How to Launch a Tech Startup and Raise Financing in the U.S. Starting a tech business in the U.S. can be a challenge and a privilege. While the market is large, the competition is intense and consumer standards are high. 46. Exploring Taiwanese Start Up Culture Following our hiring survey for Taiwan startups, this story discusses how local companies find talent, and the importance of employer branding for scalability. 47. What Are The Most Common Mistakes New Startups Make? Newbie startups fly HIGH and then fall hard! Here’s why. 48. Right Entrepreneur, Right Problem: The First Steps in Startup Building “Focus on getting your MVP’s value proposition incredibly clear. If your grandma doesn’t understand it’s probably not clear.” [49. When We Can Pitch Startups at Events Again, Take These Lessons With You](https://hackernoon.com/when-we-can-pitch-startups-at-events-again-take-these-lessons-with-you-in2jc3yio) Here I am, a twenty-year-old astrophysics student designing satellites to place in orbit around Mars and a self-starter entrepreneur longing to show my baby — nect MODEM — to the earth. I've had a few bumps on the road. Thankfully, I learned a few valuable lessons, and the experience of attending five conferences with my startup as my product made me reflect on a lot I'd like to share with other aspiring startup owners. 50. Taking on “12 Startups in 12 Months” Challenge in 2022 I am doing the 12 Startups in 12 Months challenge starting from January 2022. That means I need to build and launch one startup every single month of 2022! 51. How Tech Companies are Helping in Times of Covid-19 Crisis Since the pandemic COVID-19 is shaking all over the world, several people are dying and facing issues to earn for their livelihood. Well, big tech companies have responded with unusual alacrity and they are helping people during this crisis. 52. How to Negotiate a Letter of Intent (LOI) That Provides a Smooth Acquisition Process The buyer needs to see that there are no hidden surprises waiting for them. 53. Console #16: Fake Like Factories and Surviving the Surveillance Apocalypse 01/05/2020 54. Startups Are Thriving in LA: It's An Entrepreneurial Hot Spot In this article, there are some great insights about the Los Angeles business hub that places it in the lead in the post-pandemic era! 55. Useful Tools To Improve Your Business Performance To improve business performance, a business spends a lot of time, effort, and money unaware of the tools that can help him/her to boost business performance. 56. Product Marketer vs. Growth Marketer vs. Content Marketer: How to Choose Your First Marketing Hire Product, growth, and content marketers all have unique roles to play in your tech startup, but which should you prioritize? This article answers that question. 57. 9 Things I‘ve Learned About Running a Startup Almost 2 years ago, we launched Meddy out of a class project at college. We faced our fair share of challenges from lawsuits to team conflicts to engineering issues etc. 58. 7 Startups Founded During the Pandemic These 7 Startup Founders used the challenges presented by the Covid-19 pandemic to propel them forward. From asynchronous communication apps to a self-sanitizin 59. AI Startup Financing: 6 Best Seed Funding Options in 2022 So you have a new cutting-edge AI product/service idea. 60. The Ideal Tech Co-Founder for Your Startup: Expert Tips to Avoid Odds of Failure in 2021 Choosing a technical co-founder is one of the most important decisions you’ll make as an entrepreneur. 61. Descriptive Analysis: Why Did These 500 Trending Startups Shut Down? Discovering meaningful patterns in business failures. 62. Startup Journey: From Aviation To Fintech The ninth interview in the Startup Journey series: Building an airline out of necessity & an innovative fintech product out of passion Thank you for checking out the 62 most read stories about Tech Startups on HackerNoon. to find the most read stories about any technology. Visit the /Learn Repo

62 Stories To Learn About Tech Startups

Things To Make by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book . APPARATUS FOR SIMPLE SCIENTIFIC EXPERIMENTS. here XXVI. APPARATUS FOR SIMPLE SCIENTIFIC EXPERIMENTS. Colour Discs for the Gramophone.—The gramophone, by virtue of its table revolving at a controllable speed, comes in useful for a series of optical experiments made with coloured discs bearing designs of different kinds. The material needed for these discs is cardboard, covered with white paper on one side, or the Bristol board used by artists. The discs on which the designs are drawn should be made as large as the gramophone table will take conveniently, so as to be viewed by a number of people at once. To encourage readers who do not possess a gramophone, it may be pointed out that a gramophone, is merely a convenience, and not indispensable for turning the discs, which may be revolved on a sharpened pencil or any other spindle with pointed ends. The Vanishing Spirals (Fig. 137).—This design, if spun slowly in a clockwise direction, gives one the impression that the lines all move in towards the centre. If the disc is turned in an anti-clockwise direction, the lines seem to move towards the circumference and disappear. To get the proper effect the gaze should be fixed and not attempt to follow the lines round. [Illustration: FIG. 137.] [Illustration: FIG. 138.] The Rolling Circles.—Figs. 138 and 139 are variations of the same idea. In Fig. 138 two large circles are described cutting one another and enclosing a smaller circle concentric with the disc. When spun at a certain rate the larger circles will appear to run independently round the small. The effect is heightened if the circles are given different colours. If black only is used for the large circles, the eyes should be kept half closed. In Fig. 139 two pairs of circles are described about two centres, neither of which is the centre of the disc. The pairs appear to roll independently. [Illustration: FIG. 139.] [Illustration: FIG. 140.] The Wriggling Line (Fig. 140).—If this design is revolved at a low speed and the eye is fixed on a point, the white (or coloured) line will seem to undulate in a very extraordinary manner. The line is made up of arcs of circles, and as the marking out is somewhat of a geometrical problem, a diagram (Fig. 141) is added to show how it is done. The dotted curves are those parts of the circles which do not enter into the design. Begin by marking out the big circle A for the disc. The circumference of this is divided into six equal parts (chord equal to radius), and through the points of division are drawn the six lines from the centre. Describe circles aaa, each half the diameter of A. The circles bbb are then drawn from centres on the lines RRR, and with the same radius as aaa., The same centres are used for describing the circles a1 a1 a1 and b1 b1 b1, parts of which form the inner boundary of the line. The background should be blackened and the belt left white or be painted some bright colour. [Illustration: FIG. 141.] Another optical illusion is afforded by Fig. 142. Two sets of circles are described about different centres, and the crescent-shaped areas between them coloured, the remainder of the disc being left white. The disc is revolved about the centre of the white areas, and one gets the impression that the coloured parts are portions of separate discs separated by white discs. [Illustration: FIG. 142.] [Illustration: FIG. 143.] The Magic Spokes (Fig. 143).—Place a design like this on the gramophone and let it turn at high speed. The radial lines seem but a blur. Now punch a hole one-eighth of an inch in diameter in a piece of blackened card, and, standing well away from the gramophone, apply your eye to the hole and move the card quickly to and fro. The extreme briefness of the glimpses obtained of the moving lines seems to rob them of motion, or even make them appear to be moving in the direction contrary to the actual. Instead of a single hole, one may use a number of holes punched at equal intervals round a circle, and revolve the card on the centre. If a certain speed be maintained, the spokes will appear motionless. The substitution of a long narrow slit for a circular hole gives other effects. [Illustration: FIG. 144.] A Colour Top.—Cut a 4-inch disc out of white cardboard and blacken one-half with Indian ink. On the other half draw four series of concentric black lines, as shown in Fig. 144. If the disc is mounted on a knitting needle and spun in a horizontal plane, the black lines will appear of different colours. A clockwise rotation makes the outermost lines appear a greenish blue, those nearest the centre a dark red, and the intermediate groups yellow and green. A reversal of the motion reverses the order of the colours, the red lines now being farthest from the centre. The experiment is generally most successful by artificial light, which contains a larger proportion of red and yellow rays than does sunlight. The speed at which the top revolves affects the result considerably. It should be kept moderate, any excess tending to neutralize the colours. [Illustration: FIG. 145.] The Magic Windmill.—Mark a circle 2-1/2 inches in diameter on a piece of notepaper, resting the centre leg [of the compass] so lightly that it dents without piercing the paper. With the same centre describe a 3/4-inch circle. Join the circles by eight equally spaced radial lines, and an eighth of an inch away draw dotted parallel lines, all on the same side of their fellow lines in order of rotation. Cut out along the large circle, and then with a. sharp knife follow the lines shown double in Fig. 145. This gives eight little vanes, each of which must be bent upwards to approximately the same angle round a flat ruler held with an edge on the dotted line. Next make a dent with a lead pencil at the exact centre on the vane side, and revolve the pencil until the dent is well polished. [Illustration: FIG. 146.] Hold a pin, point upwards, in the right hand, and with the left centre the mill, vanes pointing downwards, on the pin (Fig. 146). The mill will immediately commence to revolve at a steady pace, and will continue to do so indefinitely; though, if the head of the pin be stuck in, say, a piece of bread, no motion will occur. The secret is that the heat of the hand causes a very slight upward current of warmed air, which is sufficient to make the very delicately poised windmill revolve. A Pneumatic Puzzle.—For the very simple apparatus illustrated by Fig. 147 one needs only half a cotton reel, three pins, and a piece of glass or metal tubing which fits the hole in the reel. Adjust a halfpenny centrally over the hole and stick the pins into the reel at three equidistant points, so that they do not quite touch the coin, and with their ends sloping slightly outwards to allow the halfpenny to fall away. [Illustration: FIG. 147.—Apparatus for illustrating an apparent scientific paradox.] Press the coin against the reel and blow hard through the tube. One would expect the coin to fall; but, on the contrary, the harder you blow the tighter will it stick, even if the reel be pointed downwards. Only when you stop blowing will it fall to the floor. This is a very interesting experiment, and will mystify onlookers who do not understand the reason for the apparent paradox, which is this. The air blown through the reel strikes a very limited part of the nearer side of the halfpenny. In order to escape, it has to make a right-angle turn and pass between coin and reel, and, while travelling in this direction, loses most of its repulsive force. The result is that the total pressure on the underside of the coin, plus the effect of gravity, is exactly balanced by the atmospheric pressure on the outside, and the coin remains at that distance from the reel which gives equilibrium of forces. When one stops blowing, the air pressure on both sides is the same, and gravity makes the coin fall away. The function of the pins is merely to keep the halfpenny centred on the hole. If steam is used instead of human breath, a considerable weight may be hung from the disc without dislodging it. The Magic Swingers.—The easily made toy illustrated next is much more interesting than would appear from the mere picture, as it demonstrates a very striking physical phenomenon, the transference of energy. If two pendulums are hung close together from a flexible support and swung, their movements influence one another in a somewhat remarkable way—the swing of the one increasing as that of the other dies down, until a certain point is reached, after which the process is reversed, and the “dying” or “dead” pendulum commences to come to life again at the expense of the other. This alternation is repeated over and over again, until all the energy of both pendulums is exhausted. [Illustration: FIG. 148.-Magic pendulums.] To make the experiment more attractive, we substitute for the simplest possible pendulums—weights at the end of strings—small swings, each containing a figure sitting or standing on a seat, to the underside of which is attached a quarter of a pound of lead. To prevent the swings twisting, they are best made of strong wire bent as shown in Fig. 148, care being taken that the sides are of equal length, so that both hooks may press equally on the strings. Eighteen inches is a good length. The longer the swing, and the heavier the weight, the longer will the experiment last. The swings are hung, six inches apart, from a stout string stretched tightly between two well-weighted chairs or between two fixed points. The string should be at least 4 feet long. With two equally long and equally weighted pendulums, the three following experiments may be carried out:— Let one, A, start from rest. The other, B will gradually die, and A swing to and fro more and more violently, till B at last comes to a dead stop. Then A will die and B in turn get up speed. The energy originally imparted to B is thus transferred through the string from one pendulum to the other an indefinite number of times, with a slight loss at every alternation, until it is finally exhausted by friction. Swing them in opposite directions, but start A from a higher point than B. They will each alternately lose and gain motion, but will never come to rest, and will continue to swing in opposite directions—that is, while A swings north or east B will be swinging south or west, and vice versa. Start them both in the same direction, but one from a higher point than the other. There will be the same transference of energy as in (2), but neither will come to rest between alternations, and they will always swing in the same direction. Unequal Lengths.—If for one of the original pendulums we substitute one a couple of inches longer than the other, but of the same weight, the same set of three experiments will provide six variations among them, as in each case either the longer or the shorter may be started first or given the longer initial swing, as the case may be. The results are interesting throughout, and should be noted. Three or more Pendulums.—If the number of pendulums be increased to three or more, the length of all being the same, a fresh field for observation is opened. With an increase of number a decrease in the individual weighting is advisable, to prevent an undue sagging of the string. In conclusion, we may remark that a strong chain stretched between two trees and a suitable supply of rope will enable the reader and his friends to carry out all the experiments on a life-size scale. A Smoke-ring Apparatus.—Get a large tin of the self-opening kind and cut a hole 2 inches across in the bottom. Then make a neat circular hole 1-1/4 inches in diameter in the centre of a paper disc somewhat smaller than the bottom of the tin, to which it is pasted firmly on the outside. The other end—from which the lid is removed—must be covered with a piece of sheet rubber stretched fairly tight and secured to the tin by string passed over it behind the rim. An old cycle or motor car air tube, according to the size of the tin, will furnish the rubber needed; but new material, will cost only a few pence (Fig. 149). [Illustration: FIG. 149.—Smoke-ring apparatus.] A dense smoke is produced by putting in the tin two small rolls of blotting paper, one soaked in hydrochloric acid, the other in strong ammonia. The rolls should not touch. To reduce corrosion of the tin by the acid, the inside should be lined with thin card. [Illustration: FIG. 150.—Smoke-making apparatus.] A ring of smoke is projected from the hole in the card if the rubber diaphragm is pushed inwards. A slow, steady push makes a fat, lazy ring come out; a smart tap a thinner one, moving much faster. Absolutely still air is needed for the best effects, as draughts make the rings lose shape very quickly and move erratically. Given good conditions, a lot of fun can be got out of the rings by shooting one through another which has expanded somewhat, or by destroying one by striking it with another, or by extinguishing a candle set up at a distance, and so on. The experimenter should notice how a vortex ring rotates in itself while moving forward, like a rubber ring being rolled along a stick. A continuous supply of smoke can be provided by the apparatus shown in Fig. 150. The bulb of a scent spray is needed to force ammonia gas through a box, made air-tight by a rubber band round the lid, in which is a pad soaked with hydrochloric acid. The smoke formed in this box is expelled through a pipe into the ring-making box. Caution.—When dealing with hydrochloric acid, take great care not to get it on your skin or clothes, as it is a very strong corrosive. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Archibald Williams (2005). Things To Make. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/14664/pg14664-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

APPARATUS FOR SIMPLE SCIENTIFIC EXPERIMENTS.

How it Works by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book . THE CYCLE. here THE CYCLE. There are a few features of this useful and in some ways wonderful contrivance which should be noticed. First, THE GEARING OF A CYCLE. To a good many people the expression "geared to 70 inches," or 65, or 80, as the case may be, conveys nothing except the fact that the higher the gear the faster one ought to be able to travel. Let us therefore examine the meaning of such a phrase before going farther. The safety cycle is always "geared up"—that is, one turn of the pedals will turn the rear wheel more than once. To get the exact ratio of turning speed we count the teeth on the big chain-wheel, and the teeth on the small chain-wheel attached to the hub of the rear wheel, and divide the former by the latter. To take an example:—The teeth are 75 and 30 in number respectively; the ratio of speed therefore = 75⁄30 = 5⁄2 = 2½. One turn of the pedal turns the rear wheel 2½ times. The gear of the cycle is calculated by multiplying this result by the diameter of the rear wheel in inches. Thus a 28-inch wheel would in this case give a gear of 2½ × 28 = 70 inches. One turn of the pedals on a machine of this gear would propel the rider as far as if he were on a high "ordinary" with the pedals attached directly to a wheel 70 inches in diameter. The gearing is raised or lowered by altering the number ratio of the teeth on the two chain-wheels. If for the 30-tooth wheel we substituted one of 25 teeth the gearing would be— 75⁄25 × 28 inches = 84 inches. A handy formula to remember is, gearing = T/ × D, where T = teeth on large chain-wheel; = teeth on small chain-wheel; and D = diameter of driving-wheel in inches. t t Two of the most important improvements recently added to the cycle are—(1) The free wheel; (2) the change-speed gear. THE FREE WHEEL is a device for enabling the driving-wheel to overrun the pedals when the rider ceases pedalling; it renders the driving-wheel "free" of the driving gear. It is a ratchet specially suited for this kind of work. From among the many patterns now marketed we select the Micrometer free-wheel hub (Fig. 222), which is extremely simple. The r is attached to the hub of the driving-wheel. The small chain-wheel (or "chain-ring," as it is often called) turns outside this, on a number of balls running in a groove chased in the neck of the ratchet. Between these two parts are the , of half-moon shape. The driving-wheel is assumed to be on the further side of the ratchet. To propel the cycle the chain-ring is turned in a clockwise direction. Three out of the six pawls at once engage with notches in the ratchet, and are held tightly in place by the pressure of the chain-ring on their rear ends. The other three are in a midway position. ratchet-wheel pawls When the rider ceases to pedal, the chain-ring becomes stationary, but the ratchet continues to revolve. The pawls offer no resistance to the ratchet teeth, which push them up into the semicircular recesses in the chain-ring. Each one rises as it passes over a tooth. It is obvious that driving power cannot be transmitted again to the road wheel until the chain-wheel is turned fast enough to overtake the ratchet. THE CHANGE-SPEED GEAR. A gain in speed means a loss in power, and . By gearing-up a cycle we are able to make the driving-wheel revolve faster than the pedals, but at the expense of control over the driving-wheel. A high-geared cycle is fast on the level, but a bad hill-climber. The low-geared machine shows to disadvantage on the flat, but is a good hill-climber. Similarly, the express engine must have large driving-wheels, the goods engine small driving-wheels, to perform their special functions properly. vice versâ In order to travel fast over level country, and yet be able to mount hills without undue exertion, we must be able to do what the motorist does—change gear. Two-speed and three-speed gears are now very commonly fitted to cycles. They all work on the same principle, that of the epicyclic train of cog-wheels, the mechanisms being so devised that the hub turns more slowly than, at the same speed as, or faster than the small chain-wheel, according to the wish of the rider. We do not propose to do more here than explain the principle of the epicyclic train, which means "a wheel on (or running round) a wheel." Lay a footrule on the table and roll a cylinder along it by the aid of a second rule, parallel to the first, but resting on the cylinder. It will be found that, while the cylinder advances six inches, the upper rule advances twice that distance. In the absence of friction the work done by the agent moving the upper rule is equal to that done in overcoming the force which opposes the forward motion of the cylinder; and as the distance through which the cylinder advances is only half that through which the upper rule advances, it follows that the which must act on the upper rule is only half as great as that overcome in moving the cylinder. The carter makes use of this principle when he puts his hand to the top of a wheel to help his cart over an obstacle. force Now see how this principle is applied to the change-speed gear. The lower rule is replaced by a cog-wheel, c (Fig. 223); the cylinder by a cog, b, running round it; and the upper rule by a ring, a, with internal teeth. We may suppose that a is the chain-ring, b a cog mounted on a pin projecting from the hub, and c a cog attached to the fixed axle. It is evident that b will not move so fast round c as a does. The amount by which a will get ahead of b can be calculated easily. We begin with the wheels in the position shown in Fig. 223. A point, i, on a is exactly over the topmost point of c. For the sake of convenience we will first assume that instead of b running round c, b is revolved on its axis for one complete revolution in a clockwise direction, and that a and c move as in Fig. 224. If b has 10 teeth, c 30, and a 40, a will have been moved 10⁄40 = ¼ of a revolution in a clockwise direction, and c 10⁄30 = ⅓ of a revolution in an anti-clockwise direction. Now, coming back to what actually does happen, we shall be able to understand how far a rotates round c relatively to the motion of b, when c is fixed and rolls (Fig. 225). b advances ⅓ of distance round c; a advances ⅓ + ¼ = 7⁄12 of distance round b. The fractions, if reduced to a common denominator, are as 4:7, and this is equivalent to 40 (number of teeth on a): 40 + 30 (teeth on a + teeth on c.) B To leave the reader with a very clear idea we will summarize the matter thus:—If T = number of teeth on a, = number of teeth on c, then movement of a: movement of b:: T + : T. t t Here is a two-speed hub. Let us count the teeth. The chain-ring (= a) has 64 internal teeth, and the central cog (= c) on the axle has 16 teeth. There are four cogs (= b) equally spaced, running on pins projecting from the hub-shell between a and c. How much faster than b does a run round c? Apply the formula:—Motion of a: motion of b:: 64 + 16: 64. That is, while a revolves once, b and the hub and the driving-wheel will revolve only 64⁄80 = ⅘ of a turn. To use scientific language, b revolves 20 per cent. slower than a. This is the gearing we use for hill-climbing. On the level we want the driving-wheel to turn as fast as, or faster than, the chain-ring. To make it turn at the same rate, both a and c must revolve together. In one well-known gear this is effected by sliding c along the spindle of the wheel till it disengages itself from the spindle, and one end locks with the plate which carries a. Since b is now being pulled round at the bottom as well as the top, it cannot rotate on its own axis any longer, and the whole train revolves —that is, while a turns through a circle b does the same. solidly To get an of gearing, matters must be so arranged that the drive is transmitted from the chain-wheel to b, and from a to the hub. While b describes a circle, a and the driving-wheel turn through a circle and a part of a circle—that is, the driving-wheel revolves faster than the hub. Given the same number of teeth as before, the proportional rates will be a = 80, b = 64, so that the gear 25 per cent. increase rises By means of proper mechanism the power is transmitted in a three-speed gear either (1) from chain-wheel to a, a to b, b to wheel = gear; or (2) from chain-wheel to a and c simultaneously = solid, normal, or gear; or (3) from chain-wheel to b, b to a, a to wheel = gear. In two-speed gears either 1 or 3 is omitted. low middle high About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Archibald Williams (2009). How it Works. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/28553/pg28553-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

THE CYCLE.

HYDRAULIC MACHINERY.

A HORIZONTAL SLIDE-VALVE ENGINE.

DYNAMOS AND ELECTRIC MOTORS.

How it Works by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book . THE ELECTRIC TELEGRAPH. here Chapter VI. THE ELECTRIC TELEGRAPH. Needle instruments—Influence of current on the magnetic needle—Method of reversing the current—Sounding instruments—Telegraphic relays—Recording telegraphs—High-speed telegraphy. TAKE a small pocket compass and wind several turns of fine insulated wire round the case, over the top and under the bottom. Now lay the compass on a table, and turn it about until the coil is on a line with the needle—in fact, covers it. Next touch the terminals of a battery with the ends of the wire. The needle at once shifts either to right or left, and remains in that position as long as the current flows. If you change the wires over, so reversing the direction of the current, the needle at once points in the other direction. It is to this conduct on the part of a magnetic needle when in a "magnetic field" that we owe the existence of the needle telegraph instrument. NEEDLE INSTRUMENTS. Probably the best-known needle instrument is the Cooke-Wheatstone, largely used in signal-boxes and in some post-offices. A vertical section of it is shown in Fig. 54. It consists of a base, b, and an upright front, a, to the back of which are attached two hollow coils on either side of a magnetic needle mounted on the same shaft as a second dial needle, n, outside the front. The wires w w are connected to the telegraph line and to the commutator, a device which, when the operator moves the handle h to right and left, keeps reversing the direction of the current. The needles on both receiving and transmitting instruments wag in accordance with the movements of the handle. One or more movements form an alphabetical letter of the Morse code. Thus, if the needle points first to left, and then to right, and comes to rest in a normal position for a moment, the letter A is signified; right-left-left-left in quick succession = B; right-left-right-left = C, and so on. Where a marking instrument is used, a dot signifies a "left," and a dash a right; and if a "sounder" is employed, the operator judges by the length of the intervals between the clicks. INFLUENCE OF CURRENT ON A MAGNETIC NEEDLE. igs. 55 and 56 are two views of the coils and magnetic needle of the Wheatstone instrument as they appear from behind. In Fig. 55 the current enters the left-hand coil from the left, and travels round and round it in a clockwise direction to the other end, whence it passes to the other coil and away to the battery. Now, a coil through which a current passes becomes a magnet. Its polarity depends on the direction in which the current flows. Suppose that you are looking through the coil, and that the current enters it from your end. If the wire is wound in a clockwise direction, the S. pole will be nearest you; if in an anti-clockwise direction, the N. pole. In Fig. 55 the N. poles are at the right end of the coils, the S. poles at the left end; so the N. pole of the needle is attracted to the right, and the S. pole to the left. When the current is reversed, as in Fig. 56, the needle moves over. If no current passes, it remains vertical. METHOD OF REVERSING THE CURRENT. A simple method of changing the direction of the current in a two-instrument circuit is shown diagrammatically in Fig. 57. The is used in the Wheatstone needle instrument. The battery terminals at each station are attached to two brass plates, a b, a1 b1. Crossing these at right angles (under a a1 and over b b1) are the flat brass springs, l r, l1 r1, having buttons at their lower ends, and fixed at their upper ends to baseboards. When at rest they all press upwards against the plates a and a1 respectively. r and l1 are connected with the line circuit, in which are the coils of dials 1 and 2, one at each station. l and r1 are connected with the earth-plates e e1. An operator at station 1 depresses r so as to touch b. Current now flows from the battery to b, thence through r to the line circuit, round the coils of both dials through l1 a1 and r to earth-plate e1, through the earth to e, and then back to the battery through l and a. The needles assume the position shown. To reverse the current the operator allows r to rise into contact with a, and depresses l to touch b. The course can be traced out easily. principle In the Wheatstone "drop-handle" instrument (Fig. 54) the commutator may be described as an insulated core on which are two short lengths of brass tubing. One of these has rubbing against it a spring connected with the + terminal of the battery; the other has similar communication with the – terminal. Projecting from each tube is a spike, and rising from the baseboard are four upright brass strips not quite touching the commutator. Those on one side lead to the line circuit, those on the other to the earth-plate. When the handle is turned one way, the spikes touch the forward line strip and the rear earth strip, and when moved in the opposite direction. vice versâ SOUNDING INSTRUMENTS. Sometimes little brass strips are attached to the dial plate of a needle instrument for the needle to strike against. As these give different notes, the operator can comprehend the message by ear alone. But the most widely used sounding instrument is the Morse sounder, named after its inventor. For this a reversible current is not needed. The receiver is merely an electro-magnet (connected with the line circuit and an earth-plate) which, when a current passes, attracts a little iron bar attached to the middle of a pivoted lever. The free end of the lever works between two stops. Every time the circuit is closed by the transmitting key at the sending station the lever flies down against the lower stop, to rise again when the circuit is broken. The duration of its stay decides whether a "long" or "short" is meant. TELEGRAPHIC RELAYS. When an electric current has travelled for a long distance through a wire its strength is much reduced on account of the resistance of the wire, and may be insufficient to cause the electro-magnet of the sounder to move the heavy lever. Instead, therefore, of the current acting directly on the sounder magnet, it is used to energize a small magnet, or , which pulls down a light bar and closes a second "local" circuit—that is, one at the receiver end—worked by a separate battery, which has sufficient power to operate the sounder. relay RECORDING TELEGRAPHS. By attaching a small wheel to the end of a Morse-sounder lever, by arranging an ink-well for the wheel to dip into when the end falls, and by moving a paper ribbon slowly along for the wheel to press against when it rises, a self-recording Morse inker is produced. The ribbon-feeding apparatus is set in motion automatically by the current, and continues to pull the ribbon along until the message is completed. The Hughes type-printer covers a sheet of paper with printed characters in bold Roman type. The transmitter has a keyboard, on which are marked letters, signs, and numbers; also a type-wheel, with the characters on its circumference, rotated by electricity. The receiver contains mechanisms for rotating another type-wheel synchronously—that is, in time—with the first; for shifting the wheel across the paper; for pressing the paper against the wheel; and for moving the paper when a fresh line is needed. These are too complicated to be described here in detail. By means of relays one transmitter may be made to work five hundred receivers. In London a single operator, controlling a keyboard in the central dispatching office, causes typewritten messages to spell themselves out simultaneously in machines distributed all over the metropolis. The tape machine resembles that just described in many details. The main difference is that it prints on a continuous ribbon instead of on sheets. Automatic electric printers of some kind or other are to be found in the vestibules of all the principal hotels and clubs of our large cities, and in the offices of bankers, stockbrokers, and newspaper editors. In London alone over 500 million words are printed by the receivers in a year. HIGH-SPEED TELEGRAPHY. At certain seasons, or when important political events are taking place, the telegraph service would become congested with news were there not some means of transmitting messages at a much greater speed than is possible by hand signalling. Fifty words a minute is about the limit speed that a good operator can maintain. By means of Wheatstone's the rate can be increased to 400 words per minute. Paper ribbons are punched in special machines by a number of clerks with a series of holes which by their position indicate a dot or a dash. The ribbons are passed through a special transmitter, over little electric brushes, which make contact through the holes with surfaces connected to the line circuit. At the receiver end the message is printed by a Morse inker. automatic transmitter It has been found possible to send several messages simultaneously over a single line. To effect this a is used to put a number of transmitters at one end of the line in communication with an equal number of receivers at the other end, fed by a second distributer keeping perfect time with the first. Instead of a signal coming as a whole to any one instrument it arrives in little bits, but these follow one another so closely as to be practically continuous. By working a number of automatic transmitters through a distributer, a thousand words or more per minute are easily dispatched over a single wire. distributer The Pollak Virag system employs a punched ribbon, and the receiver traces out the message in alphabetical characters on a moving strip of sensitized photographic paper. A mirror attached to a vibrating diaphragm reflects light from a lamp on to the strip, which is automatically developed and fixed in chemical baths. The method of moving the mirror so as to make the rays trace out words is extremely ingenious. Messages have been transmitted by this system at the rate of 180,000 words per hour. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Archibald Williams (2009). How it Works. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/28553/pg28553-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

THE ELECTRIC TELEGRAPH.

THE INTERNAL-COMBUSTION ENGINE.

THE CONVERSION OF HEAT ENERGY INTO MECHANICAL MOTION.

Welcome back with another problem to solve! Today, we’ll be talking about matrices and how to rotate them. We’ll see two ways of doing this: one will take extra space to accomplish the task, and the other one will do it in place! As always, these problems are provided by the wonderful newsletter Daily Problem, which you can subscribe to here! Check it out and try to solve your daily challenge! Coding Without further ado, let’s take a look at the problem, which (may) have been asked by Facebook in one of their job interviews. Given an N by N matrix, rotate it by 90 degrees clockwise. For example, given the following matrix: [[1, 2, 3], [4, 5, 6], [7, 8, 9]] you should return: [[7, 4, 1], [8, 5, 2], [9, 6, 3]] Follow-up: What if you couldn’t use any extra space? Let’s give this a try by hand with a smaller matrix and see which transformation we can apply to get the result. Matrices and transformations First off, let’s start to manually rotate a smaller matrix, for example, the matrix . [ [1,2],[3,4] ] There are basically : you can , adjusting the final position of its elements at the end, or , following the “border” of the matrix. two ways to visualize it literally rotate the actual image of the matrix you can imagine swapping each element to its right neighbor The first thing we can notice is the position of the elements after the rotation: basically, the first row has become the last column, and the second row has become the first column. We’ll discuss more about this later, but for now, we can use this approach to build our first algorithm: we’ll simply swap the rows for the columns and place them accordingly in a new matrix. The code (not in place) Let’s see how we can make the code work: we’ll use Go this time! https://gist.github.com/NicolaM94/a5a04dc9a5de808565148ea7701c5b17?embedable=true#file-main-go First off, we create a function that takes a parameter in the matrix we want to rotate and returns a new matrix , the rotated version. Right after that, we initialize the new matrix, which will be the same size as the initial matrix, just full of zeros. After that, for each row of the starting matrix, we append the elements in the right place in each column. out To better explain the concept, let’s walk it row by row in the example above, where the starting array is : [][]int{{1,2},{3,4}} row = 0 -> col = 0 -> out[0][2-1-0] = matrix[0][0] row = 0 -> col = 1 -> out[1][2-1-0] = matrix[0][1] row = 1 -> col = 0 -> out[0][2-1-1] = matrix[1][0] row = 1 -> col = 1 -> out[1][2-1-1] = matrix[1][1] One important thing to point out about this: we can use this approach because the problem explicitly states that the matrices we are working with are NxN, and so are . If they were not square, we would need to adapt the variable to manage the different sizes of rows and columns… maybe in another article! square matrices In place rotation We’ve seen how to rotate the matrix, but the job is not done yet: we still have to answer the second part. What about rotating the matrix in place? To be clear, (or, in general, applying a function in place) . We need to modify directly the given matrix and its elements to rotate it. rotating in place means applying the rotation directly on the input instance: we are not allowed to use any other space (or just a small additional constant space) to accomplish the task How? Let’s think about what we have done before: we swapped the rows for the columns. Our operation is really similar to the mathematical operation of transposition, defined as the following: Basically, for each element in in position ( ), the transposed matrix contains the same element but in position ( ). Obviously, the elements on the diagonal of the matrix will remain in the same place. So, for example, transposing the little matrix of the above example goes like this: A i, j Aᵗ i,j As you can see, rows and columns get swapped with this operation. We are not quite there, though, because the columns are not in the right order. Reordering them is not a difficult job, though. We simply reverse each row, and our job is done. Let’s give it a try, then. The code (in place) https://gist.github.com/NicolaM94/e053a95c65012cbe0c0a52d377f26654?embedable=true#file-main-go The code for this one is a bit longer, but don’t worry: we’ll break it apart as always. Let’s start from the function. This function applies what we have done manually before: for each row, we take the elements to the right of the diagonal and swap them with their corresponding element below the diagonal. We use as temporary storage for the element , swap with and swap j,i with . After that, we simply return the matrix. Transpose temp i,j i,j j,i temp Now, we need a way to reverse the rows, which is done with the function and the function. We need to write an function since Go does not have a built-in method to do so. To do this, we use the same approach as in the transpose function on a single array: we walk over the array from the first to its middle element and swap each element with its corresponding element starting from the end of the array. For instance, an array of length 5 will have indexes from 0 to 4, and we’ll exchange element 0 with element 4, element 1 with element 3 and element 2 will stay in place. invertArray InvertRows invertArray The is simply a wrapper for the function: it applies this last function to all the rows in the matrix. And finally, we wrap everything again with the last function . Again, what happens here, taking the first matrix as an example, is: invertRows invertArray RotateClockWiseIP [[1,2],[3,4]] -> [[1,3],[2,4]] -> [[3,1],[4,2]] You can use this same code to perform any rotation, clockwise and anti-clockwise, by any degree you want (90, 180, 270 or 360 obviously). Just swap the transpose function and the invert rows function, repeat them more than one time or both, and see what happens! Time complexity As always, let’s take a brief moment to discuss the complexity of the algorithm. As always, most of the time spent by both algorithms is spent inside the for loops. Both algorithms have inner for loops, too, . This is pretty obvious if you think about it: having a matrix of size N*N means having N² elements to pass on. And even if the second algorithm only walks half of the elements of both the array and the matrix, at best, we’ll have a time complexity of O(N²/2). But since we skip over multiplicative constants in time complexity evaluation, we would still be back to O(N²). so the time spent grows quadratically to O(n²) Conclusions Here’s the algorithm. What do you think about it? Let me know in the comments if you have a better version for this one! Many thanks for reading and supporting the blog. If you also would like to contribute with coffee, here’s my page where you can support even more! Ko-fi As always, thanks for reading. Nicola Also published here.

Daily Coding Problem: Rotating Matrices

SpriteKit is a powerful framework provided by Apple for creating 2D games and interactive animations. It's a versatile tool for game developers, allowing them to bring their creative ideas to life. In this article, we'll explore how to create the classic "Snake" game using SpriteKit. "Snake" is a timeless arcade game that involves controlling a snake to eat food and grow longer while avoiding collisions with the walls. Prerequisites Before we dive into the development process, make sure you have the following set up: Xcode: Download and install Xcode, Apple's integrated development environment (IDE), from the Mac App Store. Basic knowledge of Swift: Familiarity with the Swift programming language is essential for understanding the code in this article. Setting Up Your Project Let's get started by creating a new SpriteKit project in Xcode: Open Xcode and choose "Create a new Xcode project." Select the "Game" template under the "iOS" category. Fill in the project details, such as the product name and organization identifier. Ensure that the language is set to Swift. Choose "SpriteKit" as the game technology. Click "Next" and specify the project location, then click "Create." Designing the Game Collision Detection To begin with, we will determine the components of our game, and we will make the masks for collisions for them enum CollisionMask: UInt32 {
    case snakeHead = 1
    case snakeBody = 2
    case apple = 4
    case edgeBody = 8
} In the method our game scene, you'll need to implement collision detection to check if the snake has collided with the food or edge. When the snake eats the food, it should grow longer, and a new food item should appear. update(_:) Snake and Food To create the snake and food objects, we'll use . SKShapeNode final class Apple: SKShapeNode {
    convenience init(position: CGPoint) {
        self.init()
        
        self.path = CGPath(ellipseIn: CGRect(x: 0, y: 0, width: 10, height: 10), transform: nil)
        
        self.fillColor = .systemRed
        self.strokeColor = .systemOrange
        
        self.lineWidth = 2
        
        self.position = position
        
        let pBody = SKPhysicsBody(circleOfRadius: 10, center: CGPoint(x: 5, y: 5))
        
        pBody.categoryBitMask = CollisionMask.apple.rawValue
        self.physicsBody = pBody
    }
} Our snake have base items which build body: class SnakeBodyElement: SKShapeNode {
    
    var setChildSuperParent: (SKNode) -> Void = { _ in }
    
    var diameter: CGFloat { 10 }
    var runDuration: TimeInterval { 0.2 }
    
    private var isNeedAddCild: Bool = false
    private var childElement: SnakeBodyElement?
    
    init(atPoint point: CGPoint) {
        super.init()
        
        self.path = CGPath(
            ellipseIn: CGRect(x: 0, y: 0, width: diameter, height: diameter),
            transform: nil
        )
        
        let pBody = SKPhysicsBody(
            circleOfRadius: diameter / 2,
            center: CGPoint(x: diameter / 2, y: diameter / 2)
        )

        pBody.isDynamic = true
        pBody.categoryBitMask = CollisionMask.snakeBody.rawValue
        pBody.contactTestBitMask = CollisionMask.edgeBody.rawValue | CollisionMask.apple.rawValue
        
        self.physicsBody = pBody
        
        self.fillColor = .systemTeal
        self.strokeColor = .systemGreen
        
        self.lineWidth = 1
        
        self.position = point
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func removeFromParent() {
        super.removeFromParent()
        childElement?.removeFromParent()
    }
    
    func moveTo(position: CGPoint) {
        let currentPosition = self.position
        
        self.run(SKAction.move(to: position, duration: runDuration))
        
        if let child = childElement {
            child.moveTo(position: currentPosition)
        } else if isNeedAddCild {
            let newElement = SnakeBodyElement(atPoint: currentPosition)
            newElement.setChildSuperParent = setChildSuperParent
            childElement = newElement
            setChildSuperParent(newElement)
            isNeedAddCild = false
        }
    }
    
    func eat() {
        if let child = childElement {
            child.eat()
        } else {
            isNeedAddCild = true
        }
    }
} And a head: final class SnakeHead: SnakeBodyElement {
    
    override var diameter: CGFloat { 20 }
    override var runDuration: TimeInterval { 1 }
    
    private let moveSpeed: Double = 100
    private var angle: CGFloat = 0
    
    override init(atPoint point: CGPoint) {
        super.init(atPoint: point)
        
        self.name = "SnakeHead"
        self.physicsBody?.categoryBitMask = CollisionMask.snakeHead.rawValue
        
        self.physicsBody?.contactTestBitMask = CollisionMask.edgeBody.rawValue
            | CollisionMask.apple.rawValue
            | CollisionMask.snakeBody.rawValue
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func moveTo(position: CGPoint) {
        let dx = CGFloat(moveSpeed) * sin(angle)
        let dy = CGFloat(moveSpeed) * cos(angle)
        
        let nextPosition = CGPoint(x: self.position.x + dx, y: self.position.y + dy)
        
        super.moveTo(position: nextPosition)
    }
    
    func moveClockwise() {
        angle += CGFloat.pi / 2
    }
    
    func moveCounterClockwise() {
        angle -= CGFloat.pi / 2
    }
} Game Loop SpriteKit provides a built-in game loop through the method in our scene. This is where you'll update the game's logic, such as moving the snake and checking for collisions. update(_:) override func update(_ currentTime: TimeInterval) {
    // Add game logic here
} User Interaction To control the snake, you'll want to capture user input. One common way to do this is by handling touch events: override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    // Handle touch events to change the snake's direction
} Implementing Game Logic Now that you have the basic structure of game, it's time to implement the game logic. Here are some key steps: Move the snake in the direction determined by user input. Check for collisions with the walls. If the snake collides, the game should end. Check if the snake's head collides with the food. If so, make the snake longer and spawn a new food item. Keep track of the snake's length and update the score. Implement game over logic when the snake collides with the walls. Game Scene In SpriteKit, games are built around scenes. We'll begin by designing our game scene, including the snake and food elements. Open the file in your Xcode project. GameScene.swift Change the existing code: final class GameScene: SKScene {
    
    private var snake: SnakeHead?
    
    private var apple: Apple?
    
    let infoSender = CurrentValueSubject<Int, Never>(0)
    
    override init(size: CGSize) {
        super.init(size: size)
        
        scaleMode = .resizeFill
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func didMove(to view: SKView) {
        
        view.showsPhysics = true
        
        guard let viewScene = view.scene else { return }
        
        viewScene.physicsWorld.contactDelegate = self
        
        viewScene.physicsBody?.allowsRotation = false
        
        viewScene.backgroundColor = UIColor(red: 0.8, green: 0.8, blue: 0.8, alpha: 1)
        viewScene.physicsBody = SKPhysicsBody(edgeLoopFrom: frame)
        viewScene.physicsBody?.categoryBitMask = CollisionMask.edgeBody.rawValue
        viewScene.physicsBody?.collisionBitMask = CollisionMask.snakeBody.rawValue
            | CollisionMask.snakeHead.rawValue
        
        viewScene.physicsWorld.gravity = CGVector(dx: 0, dy: 0)
        
        setup(skScene: viewScene)
    }
    
    override func update(_ currentTime: TimeInterval) {
        if !isPaused {
            snake?.moveTo(position: apple!.position)
        }
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        buttonAction(touches, color: .green) { [weak self] tNode in
            if tNode.name == "CounterClockwiseBtn" && !(self?.isPaused ?? true) {
                self?.snake?.moveCounterClockwise()
            } else if tNode.name == "ClockwiseBtn" && !(self?.isPaused ?? true) {
                self?.snake?.moveClockwise()
            } else if tNode.name == "Pause" {
                self?.isPaused.toggle()
            }
        }
    }
    
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        buttonAction(touches, color: .gray)
    }
    
    override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
        isPaused = true
    }
    
    private func setup(skScene: SKScene) {
        var position = CGPoint(x: skScene.frame.minX + 30, y: skScene.frame.minY + 30)
        self.addChild(createBtn(name: "CounterClockwiseBtn", color: .gray, position: position))
        
        position.x = skScene.frame.maxX - 80
        self.addChild(createBtn(name: "ClockwiseBtn", color: .gray, position: position))
        
        position.y = skScene.frame.maxY - 80
        self.addChild(createBtn(name: "Pause", color: .systemBlue, position: position))
        
        createSnake(skFrame: skScene.frame)
        
        createApple(skFrame: skScene.frame)
    }
    
    private func createSnake(skFrame: CGRect) {
        snake = SnakeHead(atPoint: CGPoint(x: skFrame.midX, y: skFrame.midY))
        snake?.setChildSuperParent = self.addChild(_:)
        self.addChild(snake!)
    }
    
    private func createApple(skFrame: CGRect) {
        
        let randX = CGFloat(arc4random_uniform(UInt32(skFrame.maxX)) + 1)
        let randY = CGFloat(arc4random_uniform(UInt32(skFrame.maxY)) + 1)
        
        apple = Apple(position: CGPoint(x: randX, y: randY))
        
        self.addChild(apple!)
    }
    
    private func createBtn(name: String?, color: UIColor, position: CGPoint) -> SKShapeNode {
        let btn = SKShapeNode()
        
        btn.path = CGPath(ellipseIn: CGRect(x: 0, y: 0, width: 45, height: 45), transform: nil)
        btn.position = position
        btn.fillColor = color
        btn.strokeColor = .darkGray
        btn.lineWidth = 10
        btn.name = name
        
        return btn
    }
    
    private func buttonAction(
        _ touches: Set<UITouch>,
        color: UIColor,
        action: (SKShapeNode) -> Void = {_ in}
    ) {
        for touch in touches {
            let touchLocation = touch.location(in: self)
            
            guard let touchedNode = self.atPoint(touchLocation) as? SKShapeNode,
                  touchedNode.name == "CounterClockwiseBtn"
                    || touchedNode.name == "ClockwiseBtn"
                    || touchedNode.name == "Pause"
            else {
                return
            }
            
            touchedNode.fillColor = color
            
            action(touchedNode)
        }
    }
}

extension GameScene: SKPhysicsContactDelegate {
    
    func didBegin(_ contact: SKPhysicsContact) {
        let collisionObject: SKPhysicsBody
        
        if contact.bodyA.node?.name == "SnakeHead" {
            collisionObject = contact.bodyB
        } else {
            collisionObject = contact.bodyA
        }
        
        switch CollisionMask(rawValue: collisionObject.categoryBitMask) {
        case .apple:
            let apple = contact.bodyA.node is Apple ? contact.bodyA.node : contact.bodyB.node
            snake?.eat()
            apple?.removeFromParent()
            infoSender.send(infoSender.value + 1)
            createApple(skFrame: view?.scene?.frame ?? .zero)
        case .edgeBody:
            snake?.removeFromParent()
            infoSender.send(0)
            createSnake(skFrame: view?.scene?.frame ?? .zero)
        default:
            break
        }
    }
} And finally, we'll update our application to show the score: @main
struct SnakeApp: App {
    private let scene: GameScene //BloxScene
    @State private var info = "0"

    var body: some Scene {
        WindowGroup {
            ZStack {
                Color.gray
                    .edgesIgnoringSafeArea(.all)
            
                VStack(spacing: 0) {
                    Text("Score: \(info)")
                        .font(.body)
                        .foregroundColor(.white)
                
                    SpriteView(
                        scene: scene,
                        debugOptions: [.showsFPS, .showsNodeCount, .showsDrawCount],
                        shouldRender: { timeInterval in true }
                    )
                    .frame(idealWidth: .infinity, idealHeight: .infinity)
                }
            }
            .onReceive(scene.infoSender.eraseToAnyPublisher()) {
                info = "\($0)"
            }
        }
    }

    init() {
        self.scene = GameScene(size: CGSize(width: 10, height: 10))
    }
} Conclusion Creating the classic "Snake" game using SpriteKit can be a fun and educational project for both beginners and experienced game developers. This article has provided a high-level overview of the steps involved in setting up the project and designing the game scene. The real challenge lies in implementing the game logic, handling user input, and creating an enjoyable gaming experience. Remember that game development is an iterative process, so don't be discouraged by initial setbacks. With persistence and creativity, you can create a polished "Snake" game that is both engaging and entertaining. Good luck with your SpriteKit game development journey!

Creating the Classic "Snake" Game with SpriteKit

Building .NET Document API Layouts Using Flat Element Hierarchy

How to Reverse Engineer a Drone With Wireshark Using Packet Dissection

প্যাকেট ব্যবচ্ছেদ ব্যবহার করে ওয়্যারশার্কের সাথে একটি ড্রোনকে কীভাবে উল্টানো যায়

So entwickeln Sie eine Drohne mit Wireshark mithilfe der Paketzerlegung zurück

Cómo aplicar ingeniería inversa a un dron con Wireshark mediante la disección de paquetes

Comment inverser l'ingénierie d'un drone avec Wireshark à l'aide de la dissection de paquets

पैकेट विच्छेदन का उपयोग करके Wireshark के साथ एक ड्रोन को उल्टा कैसे करें

パケット解析を使用して Wireshark でドローンをリバース エンジニアリングする方法

패킷 분석을 사용하여 Wireshark로 드론을 리버스 엔지니어링하는 방법

Como fazer engenharia reversa de um drone com Wireshark usando dissecação de pacotes

Paket Diseksiyonu Kullanılarak Wireshark Kullanılarak Bir Drone Nasıl Tersine Tasarlanır?

Cách thiết kế đảo ngược máy bay không người lái bằng Wireshark bằng cách sử dụng phân tách gói

如何使用 Wireshark 使用数据包解析对无人机进行逆向工程

334 Stories To Learn About Javascript Development

Stories, News & Mentions about CLOCKWISE

Clockwise’s Stories on HackerNoon