[Neural Networks and Deep Learning] week3. Shallow Neural Network

Tue, 19 Sep 2017 Category notes deep learning Series Part 3 of «Andrew Ng Deep Learning MOOC»

Neural Networks Overview

new notation:

superscript [i] for quantities in layer i. (compared to superscript (i) for ith training example).
subscript i for ith unit in a layer

Neural Network Representation

notation:

a^[i]: activation at layer i.
input layer: x, layer 0.
hidden layer
output layer: prediction (yhat)
don't …

[Neural Networks and Deep Learning] week2. Neural Networks Basics

Wed, 13 Sep 2017 Category notes deep learning Series Part 2 of «Andrew Ng Deep Learning MOOC»

This week: logistic regression.

Binary Classification & notation

ex. cat classifier from image image pixels: 64x64x3 ⇒ unroll(flatten) to a feature vector x dim=64x64x3=12288:=n (input dimension)

notation

superscript (i) for ith example, e.g. x^(i)
superscript [l] for lth layer, e.g. w^[l]
m: number of …

[Neural Networks and Deep Learning] week1. Introduction to deep learning

Mon, 11 Sep 2017 Category notes deep learning Series Part 1 of «Andrew Ng Deep Learning MOOC»

What is a neural network?

Example: housing price prediciton.

Each neuron: ReLU function

Stacking multiple layers of neurons: hidden layers are concepts more general than input layer — found automatically by NN.

Supervised Learning with Neural Networks

supervised learning: during training, always have output corresponding to input.

Different NN types are …

[Android Dev] 2.2 Preference

Sun, 12 Feb 2017 Category notes android Series Part 6 of «Associate Android Developer Fast Track»

Save settings and configurations.

Data Persistance

5 different ways of data persistance:

onSavedInstanceState(): store state of views in k-v pairs (Bundles), used when screen rotates / app killed by system, temperary.
SharedPreferences: save k-v pairs to a file, can save primitive types.
SQLite database: complicated data types
Internal / External Storage: save …

[Android Dev] 2.1 Lifecycles

Sat, 11 Feb 2017 Category notes android Series Part 5 of «Associate Android Developer Fast Track»

Android kills background apps !!

→ onCreate() → Created →onStart() → Visible(can be seen on screen) → onResume() → Active(get focus, can interact with)

Active → onPause() → Paused(lose focus — same thing as Visible?) → onStop() → Stopped(disappeared) → onDestroy() → Destroyed(lifecycle ends)

when rotate screen, the function calling is:

onPause --> onStop --> onDestroy --> onCreate --> onStart --> onResume

note …

[Android Dev] 1.2 Connect to the Internet

Tue, 07 Feb 2017 Category notes android Series Part 2 of «Associate Android Developer Fast Track»

logging

https://developer.android.com/reference/android/util/Log.html

5 log levels: error/warning/info/debug/verbose
error/warning/info are preserved in the release of app
use class name as tag: MyClass.class.getSimpleName()

the Resources folder

https://developer.android.com/guide/topics/resources/providing-resources.html

working with …

[Android Dev] 1.3 RecyclerView

Tue, 07 Feb 2017 Category notes android Series Part 3 of «Associate Android Developer Fast Track»

Recycler View, Adaper, ViewHolder

rather than creating list items as we scroll, keep them in a queue (recycling bin) → when scrolling, the list items are recycled and re-bind to new content. RecyclerView is better version of ListView.

Adaper: bind data from data source, and provide the RecyclerView with new views …