Yusuf Tas – My little world

July 3, 2023 / Backend

Node Js Backend – Raspberry Pi 2 32bit Problem

Recently, I have started working on a side project for a non-profit organisation. They needed a volunteer management app for handling help requests and notification of the deliveries to volunteers. After some initial research and some discussions with the project manager ChatGPT, I came up with this awesome todo list:

Create backend server and API using Node js
Write an app using Flutter with Dart.

I know it is a very comprehensive list 😂Let me be clear, my only exposure to the web development was more than 10 years ago and it was just one uni course on php development. So I didn’t have a clear idea on how the steps would shape up. Now that is out of the way, I needed to learn and quickly develop the first prototype. You can see my awesome, beautiful mess of a spaghetti code here: https://github.com/yusuftas/team_volunteer

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June 26, 2023 / Reverse Engineering

Removing Ads From APK – 7Plus

Recently I got back to Person of Interest (PoI) TV series after remembering I haven’t finished it after maybe 7-8 years 😂 After searching a bit to see how I can stream it legally, I found out it was only available in 7plus in Australia to my surprise. 7plus is one of Australian broadcasting channels which also has the streaming rights for several overseas TV series, prison break is another. Luckily or unluckily I would say, it was free to stream PoI. You know the saying, if a product is free, you are the product, it came with unskippable video ads. Every 7-8 minutes or so I was being forced to watch 2-3 minutes ads which was causing a 40 minute show to become near an hour. That was making viewing the experience so horrible that I decided put a stop to this nonsense 😈

So I decided to dive into Android APK reverse engineering :

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December 31, 2021 / General Programming

Convert Web Page to Text

It has been a while since I last published a post. Finally it is time to come back to this blog and keep learning new stuff I can share. Let’s get back to business.

As the title suggests, we will take a URL of a web page and save that page in a text document. This is particularly useful when working with NLP based problems and you need textual information about something. Web is the best source of abundance of information, for example Wikipedia. But copying and pasting manually from web will not be efficient where you need to process a lot of pages. So here comes the solution, automate web to text conversion with little help from Python.

While looking for this, I came across BeautifulSoup. It is a great tool in Python for processing html. And it does have a function called get_text, how lucky we are 😀 Here is a very short function for requesting a webpage and getting text:

import urllib.request
from bs4 import BeautifulSoup


def Web2Text(url, outname):
    # Header for the http request
    user_agent = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7'
    headers={'User-Agent':user_agent,} 

    # Request and read the html from the given url
    request  = urllib.request.Request(url,None,headers)
    response = urllib.request.urlopen(request)
    data = response.read() # HTML data of the web page's source

    # Clean html
    raw = BeautifulSoup(data).get_text()
    print(raw)


    with open(outname, 'w',  encoding="utf-8") as outf:
        outf.writelines(raw)

import urllib.request

from bs4 import BeautifulSoup

def Web2Text(url, outname):

# Header for the http request

user_agent = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7'

headers={'User-Agent':user_agent,}

# Request and read the html from the given url

request = urllib.request.Request(url,None,headers)

response = urllib.request.urlopen(request)

data = response.read() # HTML data of the web page's source

# Clean html

raw = BeautifulSoup(data).get_text()

print(raw)

with open(outname, 'w', encoding="utf-8") as outf:

outf.writelines(raw)

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April 28, 2018 / Data Science

Cryptocurrency Trading Bot Using Deep Learning: Part-1 Data Gathering

Recently, cryptocurrency trading has been one of the most talked topics of the technology. With severe ups and downs, bitcoin and cryptocurrency trading gets attention from millions of investors. Its unpredictable nature and volatility attracted my attention. So I decided to develop an automated cryptocurrency bot using deep learning. The bot should be able to analyze the current trends and changes in the price and should decide when and how much it will buy or sell to make profits.

There will be several posts to break the bot into manageable parts. So this time, instead of a one script project, it will be a big project with Object-Oriented Design and several files. It would be very difficult to share all the code in one post, so if you are interested and want to run the code, you can get it from here: https://github.com/yusuftas/deep_trader_bot .

This first post will cover the part of data gathering. Since I am planning to use Deep Learning, it will need lots of data samples to make good predictions. It is possible to get historical data without all this code, but I am planning to run real time tests to see if the bot can make a profit, all this code posted here will definitely be needed.

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April 16, 2018 / Data Science

Beginner’s Guide to R

What is R? “R is a language and environment for statistical computing and graphics. R is an integrated suite of software facilities for data manipulation, calculation and graphical display” from the official website. R is a great tool to have in any Data Scientist’s skill set. It is a statistical and graphical plotting tool more than a programming language.

As I’m learning R myself, I will post what I learned along the way. It is kind of lecture note that might also be helpful to others. I will time to time update this post with more tips and tricks in R. Let’s begin.

Installing R is pretty straightforward. You can find it in the official website after chosing a mirror: https://cran.r-project.org/mirrors.html. After installing and starting R, you will see a command console, similar to how Python works with command shells, you can run any command in the shell, or create scripts and run your scripts through console. I would suggest using RStudio which is like an IDE for R environment. It makes things easier and has a nice interface. It is free for non-commercial use.

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April 10, 2018 / Computer Vision

Using Tensorflow Object Detection API with OpenCV

In this post, I will go over how to use Tensorflow Object Detection API within OpenCV. To be honest, I haven’t used OpenCV for quite some time. And after recently looking into it, I have realized how awesome OpenCV has become. It now has a dedicated DNN (deep neural network) module. This module also has functionality to load Caffe and Tensorflow trained networks. I am just so happy to see that functionality in OpenCV. Just think about it, you can use your Caffe or Tensorflow trained networks within OpenCV.

Alright, enough blubbering, let’s get back to the topic. In this post, I will use OpenCV DNN’s functionality to load a trained tensorflow network and use this network to apply object detection to a webcam stream. So in the end, we will have a display that shows webcam stream and in the stream we modify the frames and display detected objects with rectangles. Before we begin, let’s start with the result:

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April 10, 2018 / Deep Learning

Caffe Python Installation with Anaconda

Caffe is one of the famous Deep Learning frameworks. Its main core implementation is in C++ which got my attention when I started my Phd. Other than C++ it also has wrappers/interface for Matlab, Python and command line. Matlab interface is called matcaffe and python interface is called pycaffe. In this post I will talk about my observations and experiences in installation process of pycaffe.

First of all, you might ask, why Caffe or even pycaffe ?. Caffe is one of the first frameworks I learned,modified,extended etc. So I wanted to go back to it for this instance. Actually main reason is that its C++ core and python interface makes it easy for me to use OpenCV with it which will be the next topic I will post.

In this post I won’t go into too much details of Caffe / pycaffe. This post is mainly about installation and the problems you can face during installation.

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April 1, 2018 / Data Science

Fully Connected Regression using Tensorflow

After my last post on Learning the randomness, I realized I might need to post something simpler on tensorflow. So in this post I will go over a simple regression problem to show that we can teach machines at least something 🙂

Today’s problem is square function, yes the simple x^2 function :

$y = x^2$

By using tensorflow and manually generated data, we will try to learn the square function. First lets have a look at the data generation part :

datacount = 1000 

#linearly spaced 1000 values between 0 and 1
trainx = np.linspace(0, 1, 1000)                      #trainx = np.random.rand(datacount)
trainy = np.asarray([v**2 for v in trainx])


#shuffle the X for a good train-test distribution
p = np.random.permutation(datacount)
trainx = trainx[p]
trainy = trainy[p]

    
# Divide data by half for testing and training
train_X = np.asarray(trainx[0:int(datacount/2)]) 
train_Y = np.asarray(trainy[0:int(datacount/2)])
test_X  = np.asarray(trainx[int(datacount/2):])
test_Y  = np.asarray(trainy[int(datacount/2):])

#plot the train and test data
f, (ax1, ax2) = plt.subplots(1, 2, sharey=True)

ax1.scatter(train_X,train_Y)
ax1.set_title('Training data')
ax2.scatter(test_X,test_Y, color='r')
ax2.set_title('Testing data')

datacount = 1000

#linearly spaced 1000 values between 0 and 1

trainx = np.linspace(0, 1, 1000) #trainx = np.random.rand(datacount)

trainy = np.asarray([v**2 for v in trainx])

#shuffle the X for a good train-test distribution

p = np.random.permutation(datacount)

trainx = trainx[p]

trainy = trainy[p]

# Divide data by half for testing and training

train_X = np.asarray(trainx[0:int(datacount/2)])

train_Y = np.asarray(trainy[0:int(datacount/2)])

test_X = np.asarray(trainx[int(datacount/2):])

test_Y = np.asarray(trainy[int(datacount/2):])

#plot the train and test data

f, (ax1, ax2) = plt.subplots(1, 2, sharey=True)

ax1.scatter(train_X,train_Y)

ax1.set_title('Training data')

ax2.scatter(test_X,test_Y, color='r')

ax2.set_title('Testing data')

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March 31, 2018 / Data Science

Learning the Randomness – Attempt 1

Have you ever wondered how randomness work in computers ? Try the button to generate a random number :

Every time you click the button, you will randomly get a number. Isn’t it amazing that the computer, a deterministic object, can create these sequence of random numbers ? To me, this is a very interesting topic. Let me tell you something, actually what you see isn’t random. These sequences generated by using a function called pseudo-random generator.

Recently I was thinking about pseudo-random number generators. Pseudo-random number generators (prng) are functions that generate a sequence of numbers in a way that the sequence approximates randomness. The reason it is called pseudo is because the sequence is actually deterministic. If you know the starting point, you can get all the values in the coming sequence. This initial value is called the seed of the prng. So generated sequence completely depends on the value of the seed. To make a prng a true random generator, usually prng’s seed would get connected to a truly random event. For example the moment in micro seconds where a user presses the button generate. This event is totally random in terms of time, we can’t really know when the user will press. So if we were to use the moment in micro seconds as the seed of the prng, we would be able to get truly random number sequence, since the seed is randomized by a true random event.

Let’s first look at how random is this generator in reality? What if we randomly sample 1000 x points and 1000 y points and plot (x,y) to see what we get :

import numpy as np
import tensorflow as tf
import time
import matplotlib.pyplot as plt

plt.scatter(rng.rand(1,1000),rng.rand(1,1000))
plt.show()

import numpy as np

import tensorflow as tf

import time

import matplotlib.pyplot as plt

plt.scatter(rng.rand(1,1000),rng.rand(1,1000))

plt.show()

It looks pretty much random to me 🙂 So my idea is to somehow learn the randomness, but that plot basically shouts “I’m randooom. ” but still there must be something I can try, I thought. I decided to look into random seed. For a given random seed, generated random sequence is deterministic. Maybe I can generate some data, using different random seeds and generate the first random value generator will generate. If we can utilize this data to figure out the value prng will generate, we can pretty much solve the randomness.

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March 31, 2018 / General Programming

Random Walking Robots in Matlab

Hi Everyone,

In this post, I wanted share my experience of coding random walking in matlab. This was a little lecture problem for one of the courses I was tutoring. Problem is to simulate random walking robots in a 2D field:

There will be several robots in the field. Configuration of the map should be read from a file. File will respectively include : size of the field (w,h) ; number of robots; position and color marker for the each robot line by line e.g 10,10,bo
Each robot will move randomly in one of the 4 directions: up,down,left,right
When a robot has picked a direction to move, if another robot is occupying that position, it should not move for this turn.
When a robot reaches any of the boundaries, it should stop.
Animation should end when all of the given robots stops.

Let’s start with a visualization of what we are trying to get :

Random walking robots simulation

To solve this problem we will need several things. We need to read the configuration from a file, we need to generate the map plot with given settings and then generate the simulation with the given specifications. Now lets start with reading the input file.

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