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Friday, June 12, 2020

Regularization in Machine Learning, Deep Learning

Regularization can prevent overfitting and potentially make algorithm converge faster and more performant. Useful in deep learning tasks, in neural networks. Regularization acts on the loss function (cost function) by adding an extra penalty term. The penalty term depending on the method of regularization, penalizing the weight parameters so it is a function of w

Two common regularization methods:
  • Lasso 
    • Uses L1-norm
  • Ridge
    • Uses L2-norm
A trick to remember the norm is that letter L comes before letter R, so Lasso is L1 norm and Ridge is L2 norm. 

One is more likely to result in sparse solutions turning one or more coefficients zero. Which one do you think it is? 

Quiz: which formula is Lasso? Which one is ridge?

  • Regularization penalizes overly complex models
  • Large weights usually make penalty term higher, so smaller effective weights are preferred
    • Larger weights cost more
  • Regularization = regular_loss_function + extra_penalty_term(lambda, weights)
    • The extra penalty term also depends on the weights parameter and the lambda rate parameter

Thursday, June 11, 2020

WeChat Basics


  • WeChat requires approval
  • Important to decouple app with data API so we can change more after
  • Where to host WeChat app? Best hosting best API?
  • 微信开发者工具 WeChat Developer Tools
    • 三个部分组成,模拟器,编辑器和调试器
  • Developer also need a wechat account to administer and manage wechat apps and login to developer tools. It is used constantly for login, verification and testing, so it's very important. It also is like a 2 factor authentication. It is often used to verify before logging in. 
  • index.js is the main page to write your code
  • WeChat Games
    • Amazing example viral game 跳一跳
  • Performance
    • Compressed images
    • Stored locally in geo locations
  • WeChat Mini Program with AR
    • Example Armani cosmetic app allows users to try makeup
    • Other use cases for WeChat AR including gaming, real estate house previewing, open house, hotel room previewing, house shopping
    • Limited API availability, only available for some brands and developers for AR
  • WeChat voice interface
  • WeChat is a platform, not just a messaging app, it also include e-commerce, game, web browsing, search and content publishing
  • Features
  • Can create a wechat test app, previously known as sandbox
  • To test your app, click on preview on iphone to use your iphone to scan a QR code and be able to test it on your local phone
Write HelloWorld in WeChat Mini Program
When the wechat mini program launches, the onLoad function will be invoked. In index.js this code will console.log hello world. As you can see the syntax is very much similar to JavaScript and is stored in a .js script file. 

Page({

  onLoad() {

    console.log("Hello World!")

  } 

})


onLoad is a lifecycle call back function



Making WeChat Stickers - Sticker Developer
It's very important to follow community guideline and developer policies. Here's the content requirement for WeChat

Linear Algebra Review

A matrix is a grid of number

Points and vectors

||w|| length of w, also known as the magnitude of w, also the L2 norm.

U(U^T) square value of matrix is matrix U multiply by the transpose of U


Sudoku - Technical Interview

Each row can be represented using letters.Can be stored using row='ABCDEFGHI' note there are 9 letters. Iteration: for r in row : #do something

Each column can be represented using numbers. Can be store using cols ='123456789' also 9 digits. 

Use dot . as placeholder.   

Firebase Tutorial - Cool things you can do with Firebase 2020

Introduction to Firebase You control your Firebase using the Firebase console. The console manage one or many projects.  Each dat...