臺灣博碩士論文加值系統

近年來隨著網路通訊技術的日新月異以及硬體計算能力的增長，用戶們能分享到網路的內容也更為豐富。其中影音多媒體相關的應用更已經深入到了人們的日常生活中。目前為止，影音多媒體應用已經涉足了眾多領域，其中在教育領域也產生了莫大的影響。數位學習的方式儼然成為了現今學子們獲取知識的一條重要管道，但有研究指出，數位學習也附帶了一些問題，諸如網路教學資源太多無法有效吸收，無法保證學子們自主學習的意願等問題。為了解決這些問題，在本論文中，我們藉由結合WebRTC、內容傳遞網路以及一個支援WebRTC的串流伺服器開源專案，設計出一套大型的線上直播教室系統。並且採用同步式數位學習的方式，讓學子們在安排的時間內登入網站上課，而在有問題的時候可以直接透過視訊鏡頭與老師進行即時視訊討論，無須安裝任何軟體，以同時達到遠距教學、督促學習、即時解惑等多個目的。除了讓學子們能有一個良好的數位學習模式之外，本系統還能解決珍貴師資不足的問題，讓老師能夠同時對上千位學生進行授課，相信藉由本系統，我們可以讓學子們接受到最完善的學習資源與模式，並且更有效率的在學習的路程上邁進。

With the rapid development of network communication technology and the growth of hardware capacity in recent years, the content which users can share to network is more abundant. Multimedia applications have gone deeply into people's lives, such as education purpose. E-learning seems to be an effective way to acquire knowledge for students. But studies have shown that e-learning also comes with some issues, such as cannot guarantee the efficiency of learning when students learning by themselves. In order to guarantee the learning efficiency, in this thesis, we combine WebRTC, content delivery networks and a WebRTC-supported open source streaming server, and propose an online real-time classroom. In the scenario, students have to login the website and attend the class at the scheduled time. And the students’ problem can be solved by having a real-time video discussion with the teacher. In addition to providing a good e-learning model for students, this system also solves the problem of the shortage of teachers, let one teacher be able to teach thousands of students at a certain time. We believe that students can retrieve a good learning experience and learn in a more effective way in their learning processes.

Table of Contents
摘要 II
Abstract III
致謝 IV
Table of Contents V
List of Figures VIII
List of Tables X
1. Introduction 1
1.1 Motivation and Challenge 4
1.2 Organization of Thesis 7
2. Background and Related Work 8
2.1 Large Scale Streaming Architecture Research 8
2.1.1 Content Delivery Network (CDN) 8
2.1.2 Peer to Peer Network (P2P) 10
2.1.3 CDN-P2P Hybrid Network 11
2.1.4 Comparison 12
2.2 Edge Server Selection Algorithm Research 14
2.3 WebRTC 17
2.3.1 WebRTC Architecture 17
2.3.2 Potential of WebRTC 20
3. System Design 21
3.1 System Goal 21
3.2 System Overview 23
3.3 System Architecture 25
3.3.1 A WebRTC-based online classroom system 26
3.3.1.1 Control Server Module 26
3.3.1.2 Edge Server Module 27
3.3.1.3 End User Module 29
4. Implementation 30
4.1 Environment Setup 30
4.2 Control Server Module 31
4.2.1 Edge Server Status Initialization 31
4.2.2 Edge Server Selection Algorithm for User 35
4.2.3 Classroom Monitor Module 37
4.3 Edge Server Module 37
4.3.1 Janus WebRTC Gateway Server 37
4.3.2 Resource Monitor Module 38
4.3.3 Round-Trip-Time Measure Module 38
4.3.4 Edge Server to Edge Server Connection Module 39
4.4 User Application Interface Module 41
4.4.1 Login interface 41
4.4.2 Online Classroom Interface 42
4.4.2.1 One to Many Video Room 42
4.4.2.2 One-to-One Video Call 43
4.4.3 Admin Interface 44
5. Conclusion and Future Works 45
List of References 46

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