1/5/2008 Talk Outline

Student Oral

A general architecture of mobile social network services.
Empirical analysis of online social networks in the age of Web 2.0
802.15.4 Wireless Mobile Application for Healthcare Systems
Destination Wi-Fi
Towards the wireless office

Please tell me the url of your presentation materials and I will be happy to put them here.

Talk Outline 12-29-2007

Student Oral * 3

• Yao-Jen Chang, Hsin-Yu Hsu, Frank Tsen-Yung Wang, Action Science Approach to Context Aware Personalized Housing Services using Web 2.0 Mapping Tools- A Nonprofit Case Implementation, NCS 2007, Dec. 20-21, Taiwan.
  

• Yao-Jen Chang, Yao-Sheng Chang, Shu-Yu Hsu, Chiu-Hui Chen, Social Network Analysis to Blog-based Online Community, to be presented in International Conference on Convergence Information Technology 2007, Gyeongju, Korea. November 21~23, 2007. (EI)

Talk Outline 12-22-2007

1. Student Oral

• G. Trentin. Networked Collaborative Learning in University Teaching, Education Technology, Oct 2006. pp20-25.
  

2. Lecture

• Web 2.0
• 802.11 (Text: 2-88~2-107)

Talk Outline 12-15-2007

1. Student Oral

Subject Area: Web 2.0

Yao-Jen Chang, Tseng-Yun Wang, Shi-Kai Tsai, Yu-Chia Chuang, "Action Science Approach to Experimenting Nonprofit Web 2.0 Services for Employment of Individuals with Mental Impairments" 2007 International Workshop on Social Media Analysis in conjunction with ACM/IEEE Web Intelligence 2007. (EI)

Yao-Jen Chang and Chiu-Hui Chen, "Methodology and Evaluation of Teaching Computer Programming Laboratory with Social Media," ED-Media 2007, Vancouver, Canada, June 25-29, 2007.

2. Lecture

Web 2.0

12-8-2007 Talk Outline

telecom, 2G, 2.5G, 3G (IMS, IP Multimedia Subsystem), 3.5G/HSDPA
Computer Communications (IT), IP-based, WiFi (Data Comm.), WiMAX

Telecom enters IT sectors

• Nokia N Series, computer
• E Series, for enterprises, email & office s/w
• Voice xxxx

WiMAX vs. HSDPA

• similar:Handover, Multimedia (<>
• difference: physical, initial cost, TCO (Total Cost Ownership)

12-1-2007 Talk Outline

OFDM (Text pp 2-55 ~2-87, Handout pp. 86-91)

1. Student Oral

P1: g9577601
P2: Claire
P3: Chen

ps: slides sample.

CSMA

CSMA p-persisitent, 1-persistent

• offerer load vs. throughput behavior & mechanism (Textbook pp. 2-48~2-51)
• CSMA/CD improves performance
  

Road to high speed communication

• drawbacks of CSMA/CD in long distance and high speed communications
• interference and noise
• Shannon Theory
• the need of modulation for practical communication enigineering
  
• nonlinear characteristics of modulation and reduction of nonlinear effects
  
• Optical communication
• Wavelength Division Multiplexing (WDM)

Student Oral Presentation on Dec 1, 2007

Student Oral

P1: g9577601
P2: Claire
P3: Chen

ps: slides sample.

random access nature

We will discuss the random access nature of multiple wireless user networks.

the use of dynamic programming in controlled Aloha.

evolution of contention based protocols:
1. ALOHA
2. CSMA (Carrier Sense Multiple Access)
3. CSMA/CD (collision detection) -> IEEE 802.3 (Ethernet, 100M, 1Gbps)

MAC

Data Link Control

• MAC, Medium access control
• LLC, Logical link control
  

802.11 vs. 802.3

• 802.11 CSMA/CA

Carrier Sensed Multiple Access/ Collision Avoidance

• 802.3 Ethernet

CSMA/CD, Carrier Sensed Multiple Access/ Collision Detection

10-20-2007 Talk Outline

Outline

Random Access of Wireless Networks

We will discuss the random access nature of multiple wireless user networks. A basic coverage can be found in Sec. 2-3-2 of Textbook.

We will also cover the wireless location privacy protection as discussed in the paper by Schilit et al.

The second part of the class is a continuous introduction to new applications of BWA.

Lecture Outline, Sep 22, on Trends of Broadband wireless access

• Check this out! In each track, you will see the topics being pursued.
• For cross-layer issues, please refer to a previous post.
• Way finding based on QR codes

Limitations of Spread Spectrum and OFDM

Spread Spectrum needs synchronized despreading which can be degraded by multipath effects.
OFDM relies on orthogonality of subcarriers, and the frequency drifts will offset the orthogonality. Multipath effects will not hurt OFDM, because they do not change frequency.

extended reading: Sec 2-3-1-d & Sec 2-3-1-e of Textbook

Network Coding

Traditional packet switching treats packets as "cars" that often cause congestions at junctions like bridges and routers the way cars jam at intersections. Network coding treats junctions as encoders that can mix multiple packets and decode later at other junctions. When multiple packets arrive at the same junction, they are not queued to be served. Instead, they are coded together. So basically the congestion does not exist any longer.

It may be very useful in wireless communications as well as wired computer communications.

extended reading: Network coding(full text)

TCP is confused by packet collision in wireless environments

In wired communications, it is safe to assume a lost TCP packet is due to congestion which slows down transmission by narrowing TCP windows. However, in the wireless world, lost packets are often caused by collisions. However, TCP mistake the collisions for congestions. That's why TCP is not a very good protocol for wireless packet communication.

extended reading. Sec 1-2-2 of Textbook.

Issues of Voice over Wi-Fi

1. 802.11 QoS

absence—until very recently—of a standards-based solution for prioritizing

2. Fast Hand-off between APs

re-authentication between APs takes time such that voice suffers.

Product Solution : "UltraThin" access points (APs) & packet-by-packet micro-management of multiple data streams means that adjacent APs are never broadcasting at the same time

segregate different types of traffic (e.g., voice and data) on different radios, completely eliminating the 'contention' issue or need to prioritize traffic

background: Wi-Fi—802.11b and 802.11g—there are only three non-overlapping channels

3. UMA, unlicensed mobile access

PhoneWi-Fi Cell Phone T-Mobile Ready

1. With voice revenue slowly declining, operators are looking towards content to make up the difference.
2. They're banking on dual-mode convergence as one tool to do so.
3. The additional bandwidth of a Wi-Fi network should encourage mobile subscribers to use more data services, such as Web, e-mail, MMS, music, video, handset TV, etc."

Design Issues of Wireless Applications

Business models

End user devices (diversified)

Infrastructure

Ecology and value chain

Killer Applications

Reading list for this semester

• Yao-Jen Chang, Shan-Yao Wu, Ting-Liang Shih, Intersection Location Service and Performance Comparison of Three Location Service Algorithms for Vehicular Ad Hoc Networks in City Environments, SimuTools 2008, Marseille, France. (EI)
• Yao-Jen Chang, Hsin-Yu Hsu, Frank Tsen-Yung Wang, Action Science Approach to Context Aware Personalized Housing Services using Web 2.0 Mapping Tools- A Nonprofit Case Implementation, WWW 2008, Beijing, China. (EI)
• Yao-Jen Chang, Shih-Kai Tsai, Yao-Sheng Chang, Tsen-Yung Wang Wayfinding Systems Based on Passive RFID for Individuals with Cognitive Impairments, Pervasive Health 2008, Temepre, Finland 2008. (EI)
• Yao-Jen Chang, Shih-Kai Tsai, Li-Der Chou, Tsen-Yung Wang, Wayfinding Systems Based on Geo-coded QR Codes and Social Computing for Individuals with Cognitive Impairment, (accepted as a Journal paper.), to be presented in International Conference on Convergence Information Technology 2007, Gyeongju, Korea. November 21~23, 2007. To appear JCIT.
  
• Yao-Jen Chang, Yao-Sheng Chang, Shu-Yu Hsu, Chiu-Hui Chen, Social Network Analysis to Blog-based Online Community, to be presented in International Conference on Convergence Information Technology 2007, Gyeongju, Korea. November 21~23, 2007. (EI)
• Yao-Jen Chang Hung-Huan Liu, Li-Der Chou, Yen-Wen Chen, Haw-Yun Shin, A General Architecture of Mobile Social Network Services, to be presented in International Conference on Convergence Information Technology 2007, Gyeongju, Korea. November 21~23, 2007. (EI)
• Yao-Jen Chang, Tseng-Yun Wang, Yu-Chia Chuang, Shih-Kai Tsai, “Ontology-based Personalized Wayfinding System Using Deviation Detecting for Individuals with Cognitive Impairments” to be presented in International Conference on Convergence Information Technology 2007, Gyeongju, Korea. November 21~23, 2007. (EI)
  

• Yao-Jen Chang, Tseng-Yun Wang, Shi-Kai Tsai, Yu-Chia Chuang, "Action Science Approach to Experimenting Nonprofit Web 2.0 Services for Employment of Individuals with Mental Impairments" 2007 International Workshop on Social Media Analysis in conjunction with ACM/IEEE Web Intelligence 2007. (EI)
  
• Yao-Jen Chang, Shih-Kai Tsai, Yao-Sheng Chang, Tseng-Yun Wang "A Novel Wayfinding System Based on Geo-coded QR Codes for Individuals with Cognitive Impairments," to be presented in 9th International ACM SIGACCESS Conference on Computers and Accessibility, Oct. 15~17, 2007. (EI)
  
• Yao-Jen Chang, Tseng-Yun Wang, Sky Tsai, Yu-Chia Chuang "Nonprofit 2.0 Web Services- Case Study of Employment Services for Individuals with Mental Impairments" to be presented in IEEE TENCON 2007. (EI)
  
• Yao-Jen Chang, Shih-Kai Tsai, Yen-Yin Chu, Tseng-Yun Wang, "Social Computing on Online Wayfinding Training for Individuals with Cognitive Impairments" to be presented at E-Learn 2007, Quebec City, Canada, Oct. 15-19, 2007.
  
• Yao-Jen Chang and Chiu-Hui Chen, "Methodology and Evaluation of Teaching Computer Programming Laboratory with Social Media," ED-Media 2007, Vancouver, Canada, June 25-29, 2007.
  

團隊裡為什麼要使用討論版

好處
1. 減少 mail 轟炸
2. 可以讓別人知道你做什麼，給你建議。
3. 我們的討論可以被其他人學習，別人以後面對類似問題，不需從零開始，因而受益。
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ps. 私人議題當然還是用 e-mail