1. a;Read and then comment on the following papers.
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.
在這篇論文中,提出ILS (Intersection Location Service)與GLS (Grid Location Service) 及 HLS (Hierarchical Location Service)在多種不同環境下作相互比較,透過實地測試後ILS演算法皆有更佳的表現,不論是高速行駛狀況或車流量的情形下。同時以車輛的行進方向對ILS,GLS,HLS所造成的影
響最多,而以ILS 而言,區域影嚮最小,因此更適合在高移動性而且行車密度高的都會型街道中。
b;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)
Web1.0的時代,製作開發網頁資訊相當耗時,但是在Web2.0的時代,網頁上的資訊內容可由全球各地的網路使用者來提供,以”人”為出發點、群體智慧、跨平台使用分享與參與、持續更新、內容與服務的整合、快速反應與功能新增等。透過WEB2.0的技術平台,記錄精神障礙者的學習過程與工作訓練,輔導員也可透過WEB2.0的平台,分享輔導的過程與經驗,強化社群互動的功能。
2. Why is CSMA/CA instead of CSMA/CD used for 802.11?
最主要原因是"無線電波上偵測碰撞現象不易"!
CSMA/CA是無線網路媒體存取的方式,與乙太網路的CSMA/CD協定相似,差別在於乙太網路是利用碰撞偵測的方式,但由於碰撞偵測無線訊號有所困難,因此CSMA/CA改採取避免碰撞(Collision Avoidance)的方式,藉以提高無線網路的存取效率。
2007年11月10日 星期六
2007年9月28日 星期五
3. According to lecture notes on Page 2, what is social network? Why is the positioning a major factor in mobile social network service?
Social Network =經典定義為“分享共同興趣的人群集合。
”具體的定義︰
“The personal or professional set of relationships between individuals. Social networks represent both a collection of ties between people and the strength of those ties. Often used as a measure of social “connectedness”, recognizing social networks assists in determining how information moves throughout groups, and how trust can be established and fostered.”
”具體的定義︰
“The personal or professional set of relationships between individuals. Social networks represent both a collection of ties between people and the strength of those ties. Often used as a measure of social “connectedness”, recognizing social networks assists in determining how information moves throughout groups, and how trust can be established and fostered.”
2. Read Sec. 1-3-6 of Textbook. What is the disadvantage of Mobile IP and what's the solution?
- Mobile IP 有安全性的問題, 如Home Agent必須要認證某一個Mobile Host,不然很有可能被有心人士冒充,另外就是防火牆的問題,大部分的防火牆是使用封包的來源作為判斷,當Mobile Node試著和Home Network作接觸時,防火牆會把封包當在外面,因為這個位址是來自外面,但是卻想要使用防火牆內部的位址。所以在合併使用Mobile IP和防火牆時,要特別更改防火牆的設定才可以。
- (Solution);技術不斷發展, Mobile IP也因此不斷衍生出改良版本, 包括階層式Mobile IP(Hierarchical MIP),快速交接式Mobile IP(Fast handover MIP)及區域式Mobile IP(Regional MIP)。
1. "Mobile IP", IEEE Communication Magazine, May 1997
2. "Mobile Network Through Mobile IP", IEEE Internet Computing, Jan./Feb.1998
3. 3GPP, WWW.3GPP.ORG
4. 3GPP2,WWW.3GPP2.ORG
5. Nortel Mobile IP White Paper, WWW.NORTEL.COM
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