Supervisor: Dr. Cheng Reynold
Cheng Man Fung Kevin 3035042423
Fung Chin Pan 3035044641
Lau Hiu Tsun 3035042423
Tso Hei Lok 3035043738

Agenda
 Background & Related Work
 Objectives
 How to Achieve
 Development Platform
 About Our Application
 Other Technologies Utilized
 Demo
 Conclusion

Background
 Difficulties:
 Manually Paper Work Process
 Time-consuming & costly
 Onsite Interview Site Problem
 Bad Network Connection Problem
 Decision Making
 How to select a right candidate
Develop an All-in-one Application

Related Work
 Existing System
 Management of the applicants’ information
 Improvement on user interface & presentation of data
 Face-to-face Interview
 No functionality on Video Conferencing & Recording

Related Work
 Existing Product
 Some may include
 Video conferencing function
 Analysis on the effectiveness and consistency across interviewers
 Excellent interfaces on managing applicants’ information
Combined them all together, we get a Portable and Intelligent Interview System !!

Objective
 Diversity
 Functionalities to manage information

Portability
 Handling of bad network connection problem
 Intelligence
 Analysis on interviewee

How to Achieve

Diversity
 All-in-one System

Text processing, video conferencing, recording & etc.
 A Server allowing access from around the world
 Keeping information inside confidential

How to Achieve
 Portability
 Online System
 Offline System
 To handle bad network environment
 Simple to use

How to Achieve
 Intelligence
 Statistical Analysis
 Presentation of pass data in Charts

Comparison among different years of data
 Data-mining
 Text Mining
 Naïve Bayes Classifier

Development Platform
 LAMP
 Ubuntu, Apache Server, MySQL, PHP5
 Developed for a long time
 Free & Open-source software

Development Platform
 MVC Model
 Model
 View
 Controller
 CodeIgniter
 Build-in libraries
 Developed for years

IntelliJ IDEA over Eclipse IDE
 Smarter auto-completion
 Class name / method signatures / variables

IntelliJ IDEA over Eclipse IDE
 Optimized Default Controls for Keyboard
 Refactoring, error fixing, generation of code
Key Binding:
Alt-Insert
Key Binding:
None (Manual
Configuration needed)

Business Flow
 Preparation phase
System admin
(root) create new round
Add staff
(helpers / reviewers) to new round
Accept student applicants

Business Flow
 Pre-interview phase
Helpers provide summary to student applicants (helper’s comment)
Reviewers have a chat by conferencing with the student applicants of interest
Staff add new students manually if necessary

Business Flow
 On-site interview phase
Student
Applicants’ information prepared
Conduct interview and record with video functionality
/ camcorder
Manage comments and interview videos
(Optional, for offline module only)
Upload comments and interview videos

Business Flow

Post on-site interview
Review student’s full record
Automated analysis (on-site comment analysis, map analysis, chart analysis)
 Sundry Item
Email Functionality

Special Feature
 Video Conferencing

Impossible to arrange interviews for all the applicants
 Video Recording

Difficult for some of the reviewers to participate the onsite interview

Special Feature

Secure Socket Layer (SSL)
 application layer confidentiality
 symmetric key encryption
 protection against network packet capturing software

Special Feature

Analysis
 Map analysis

Distribution of the location of university of current year applicants
 Comment Analysis
 Suggestion of whether the student applicants should be accepted or not
 Chart analysis
 Statistical information of current round for better planning and coordination in future

No-Network Capability
 Endure the unstable, low bandwidth or even no network situation

Develop offline module
 Manage onsite comments and interview videos
 Upload the managed comment with one click when network is stable

Minor items
 Student list filtering
 Email
 Student view application
 View application

System Architecture
(fyp14003s1.cs.hku.hk)
Online Module @ HKUCS
Database
Web Server
+
WebRTC
Node JS server
Interne t
Interview round management
User account management
Comments and video management
Analysis
Email functionality
Offline
Module
Geolocation with
Unstable/NO
Internet Access
Manage student applicants’ onsite interview comment and video
View student applicants’ information
Bring back
Bring into

Database Design

Model View Controller (MVC) pattern
 Passive view model
 Controller: communicating component
 View component: presentation of data
 Model: logical evaluation

Views further organized
 Advantage: separation of code

Decorator Pattern
 Helps filtering of student applicants list
 Reduces number of subclasses by decorator chaining
 Improves code quality

What is WebRTC?

Free
 open source
 Real-Time Communications (RTC)

Why WebRTC?
 No plug-in
 open source
 free

Standardized
 efficient

WebRTC work on?
 Chrome
 Opera
 Firefox

WebRTC applications do
 Get streaming
 Audio

Video
 Other data

WebRTC applications do
 Get network information
 IP address
 Ports

Coordinate signaling communication
 Exchange information about media
 Communicate streaming

WebRTC implements APIs
 MediaStream
 Audio
 Video
 RTCPeerConnection
 establish communication channel
 RTCDataChannel
 prepare for signaling

MediaStream
 synchronized streams of media

Signaling
 not specified by WebRTC standardize
 Choose by WebRTC app developer
 Session Initiation Protocol (SIP)
 Extensible Messaging and Presence Protocol (XMPP)
 XMLHttpRequest (XHR)
(We use Socket.io running on a Node server)

Signaling
 Exchange three types of information
 Session control messages
 Network configuration
 Media capabilities

RTCPeerConnection
 Make the communication of streaming data between peers.
 Stable
 efficient

Something about the system
 Socket.io running on a Node server
 currently support 1 to 1 conferencing

RecordRTC
 JavaScript-based media-recording library
 A recording solution

Security
 Problems
 Man in middle
 Data access right issue
 Malware or viruses might be installed

WebRTC’s Security
 secure protocols
 Datagram Transport Layer Security (DTLS)
 The Secure Real-time Transport Protocol (SRTP)
 Encryption is mandatory
 Not a plug-in
 Media access must be granted explicitly

Reviewers’ comment analysis
 Naïve Bayes Classification
 Efficient
 Tutorials from the internet

Data preparation
 Classified comments into positive and negative
 Extract words
 Calculating Conditional Probabilities
 Find the largest value to determine the class

Reviewers’ comment analysis
 Testing
 75% training data, 25% testing data
 24 testing comments (21 positive, 3 negative)
 Accruacy 90%
 19 positive, 5 negative

21 positive comments, 19 of them are classified as positive
 3 negative comments, all of them are classified as negative

Google map geolocation
 Send a request to google server
 Short form or full name also accepted
 HKU and The University of Hong Kong
 Receive response
 Put a marker on the map

Google Chart API
 Show Statistical data
 Loading some Google Chart Library
 Input data
 Select options
 Create chart object

Showed on javascript

 Apache HTTPClient
 Construction of HTTP GET and POST messages
 GSON
 JSON parsed into and from java object
 Guava
 Creation of structured constant maps by collection builder.

Progress- completed
 Online System
 E-mail system
 Video conferencing
 Onsite and pre-interview video uploading
 Search form of students
 Managing accounts
 Managing rounds
 Analysis on reviewers’ comment
 Reading and modifying comments
 WebRTC recording in Firefox

Progress- completed
 Offline system
 Synchronization with online system
 Video saving
 Viewing student information
 Modifying reviewers’ comments

Progress- under development
 Google map analysis
 Cross-year analysis
 UI design

Statistical analysis

Progress- to be implemented





Beta version for professor testing

Smoke test has done
 Need further testing for its robustness
 We are glad to receive feedbacks for improvement
Study WEKA for data mining
Video recording in Google Chrome
“walk-in” student support
Pre-interview conferencing

Future Development
 WEKA
 a collection of machine learning algorithms
 applied directly to a dataset
 Java code
 data pre-processing, classification, regression, clustering, association rules, and visualization
 Cross year analysis
 Provide more statistical information

Future Development
 “Walkin” student support
 Student who did not register
 Offline system support

Pre-interview conferencing
 No way to invite a student to start a conferencing
 Solution
 A dialog box to accept the conferencing

Possible Difficulties
 Reviewers comment analysis
 Accuracy
 <100 student information
 75% training data, 25% testing data
 Large variance
 Need more data from next few years

Possible Difficulties
 Consistency
 RecordRTC
 Firefox

Record video and audio in one file
 Chrome

Record video and audio in one file separately
 Solution
 FFmpeg
 An application can merge media file

Support most of the file type
 Webm
 Wav

Reference








SSL how to import cert to Java Keystore: http://letmehelpyougeeks.blogspot.hk/2009/07/adding-servers-certificate-tojavas.html
XAMPP: SSL Encrypt the Transmission of Passwords with https: http://robsnotebook.com/xampp-ssl-encrypt-passwords
How To Create a SSL Certificate on Apache for Ubuntu 14.04: https://www.digitalocean.com/community/tutorials/how-to-create-a-ssl-certificateon-apache-for-ubuntu-14-04
Apache HTTP Client: http://hc.apache.org/httpcomponents-client-ga/index.html
Google GSON: https://code.google.com/p/google-gson/
Google Guava: https://code.google.com/p/guava-libraries/
Decorator Pattern: http://en.wikipedia.org/wiki/Decorator_pattern
IntelliJ IDEA: https://www.jetbrains.com/idea/