第五章 線性順序 Web Services 整合問題
5.4 OPT 演算法時間複雜度
最後，我們去計算這 OPT 演算法的時間複雜度，OPT 演算法運用 Matrix 的 資料結構來紀錄 m 個 Web Services 與 n 個工作任務的支援關係。根據 OPT 演算 法的第一步，是將 Web Services 細化成只支援單一個或是連續工作任務的微型 Web Services，因為每個 Web Services 最多可細化成 n/2 個微型 Web Services，一 共有 m 個 Web Services 需要細化，所以第一個步驟的時間複雜度為 O(mn) (format is not right)；OPT 演算法的第二個步驟是依可支援的第一個工作任務為基準，將 所有的微型 Web Services 做排序，所以時間複雜度為 O(mnlogmn)；第三步為移 除多餘的微型 Web Services，接下來分配工作任務給微型網路服務，分配完後進 行更新網路服務的支援關係，不斷的重複第三個步驟直到所有的工作都被分配完 成為止。因為整個移除動作的時間複雜度為 O(mn)、分配工作的時間複雜度為
O(n)，而更新網路服務的支援關係的時間複雜度亦為 O(n)；因此我們可以算出整
個 OPT 演算法的時間複雜度是 O(mn+mnlogmn)。所以本篇論文所提出的 OPT 演 算法是 polynomial time 最佳化演算法，可以在 polynomial time 內完成工作任務 分派的工作。第六章 結論與未來展望
由於 Web Services 的應用愈來愈廣，而且功能也有趨向愈來愈複雜的傾向，
從網際網路上尋找各地可以完成工作任務的 Web Services，加以組成整合以支 援較複雜的服務請求，也是必然的趨勢，然而在 Web Services 整合方面，仍有 許多的值得深入探討的議題。本篇論文主要研究探討 Web Services 整合問題，
並提出運用 Hop 數來評估 Web Services 整合的服務品質，進而提出兩種不同 的的 Web Services 整合問題，根據服務請求工作任務的相依關係，概略將全新 的 Web Services 整合問題分成獨立 Web Services 整合問題以及線性順序 Services 整合問題，兩大方向來加以討論。
在探討獨立 Web Services 整合問題時，利用集合覆蓋問題者的推導轉化，加 以證明獨立 Web Services 整合問題為 NP-complete。針對獨立 Web Services 整 合問題，本篇論文提出一個 IHGS 演算法，並進一步與 Greedy 和 HGS 兩個演 算法加以比較三個演算法的效能，經實驗模擬，在 Web Services 數量比較少 時，本篇所提出的 IHGS 演算法求得整合數量較少的 Web Services。而在 Web Services 數量比較多時，IHGS 演算法的效能亦比 HGS 演算法來得好。
本篇論文亦針對線性順序 Services 整合問題提出一個最佳化的 Web Services 排程演算法，可找出完成一項複雜的 Web Services 需要的最少 Hop 數的 Web Services 集合，以減少完成服務請求的反應時間。並用兩個不同形態的案例加 以說明，並證明我們所提出來的演算法的確是可以找出最佳的結果。根據我們 所提出的 OPT 演算法可以找出完成一個最少 Hop 數的 Web Services 集合，由 於此 Web Services 集合的 Hop 數最少，所以用以 Web Services 彼此間傳遞相 關訊息的通訊次數(或時間)為最少，除了可以加進完成服務請求的反應時間 外，因使用的 Web Services 少，亦可提昇整體的可靠度，且因用以傳遞相關訊 息的通訊次數最少，亦可降底訊息傳遞時遭竊聽或是篡改的可能性，而提昇安 全性。
未來，我們將可再延伸針對不同的工作相依關係，例如部份相依關係等，加 以探討其整合問題。亦可以探討若 Web Services 完成工作任務的計算時間亦需 要考量的情況，以便求得一個更完整的 Web Services 排程的方法，提供使用者 更有效率的 Web Services 整合機制。
參考文獻
[1] Microsoft, ”MSDN Architecture Center,”
http://msdn.microsoft.com/en-us/architecture/aa948857.aspx [2] Sun, “Service Oriented Architecture (SOA),”
http://www.sun.com/products/soa/index.jsps [3] IBM, ”Service Oriented Architecture (SOA),”
http://www-306.ibm.com/software/solutions/soa/
[4] IBM, “New to SOA and Web Services,”
http://www.ibm.com/developerworks/webservices/newto/websvc.html [5] Oracel, “Service-Oriented Architecture,”
http://www.oracle.com/technologies/soa/index.html
[6] Munindar P. Singh and Michael N. Huhns, Service-Oriented Computing:
Semantics, Processes, Agents, John Wiley and Sons, Ltd., 2005
[7] Amelia Maurizio, James Sager, Peter Jones, Gail Corbitt, and Lou Girolami,
“Service Oriented Architecture: Challenges for Business and Academia,” The
41
stAnnual Hawaii international Conference on System Sciences, pp.
315-322, Jan. 2008.
[8] Yefim V. Natis, “Applied SOA: Transforming Fundamental Principles into Best Practices,” Gartner Research Note, Id G00147098, April 2007.
[9] John McCormick, “6 Keys to SOA Success,” Baseline, May, 2007, http://www.baselinemag.com/article2/0,1540,2139359,00.asp
[10] Dan Woods and Thomas Mattern, Enterprise SOA: Designing IT for Business
Innovation, O’Reilly, April 2006.
[11] Nicolai M. Josuttis, SOA in Practice: The Art of Distributed System Design, O’Reilly, August 2007.
[12] Thomas Erl, SOA Principles of Service Design, Prentice Hall, July 2007.
[13] Google Video, http://video.google.com/?hl=en
[14] YouTube- Broadcast Yourself, http://www.youtube.com/?gl=TW&hl=zh-TW [15] Wikipedia, http://www.wikipedia.org/
[16] Kwei-Jay Lin, “The Design of an Accountability Framework for Service Engineering,” The 41st Hawaii International Conference on Systems Science, pp.108-116, January 2008.
[17] Chung-Sheng Li, “Managing Business Integrity Across Policies, Processes and Information,” IBM Information On Demand, 2007.
[18] OMG, ”CORBA Website,” http://www.corba.org/
[19] Microsoft, ”DCOM Technical Overview,”
http://msdn.microsoft.com/en-us/library/ms809340.aspx [20] Sun, “Remote Method Invocation Home,”
http://java.sun.com/javase/technologies/core/basic/rmi/index.jsp
[21] W3C, ”Web Services Description Language (WSDL) Version 2.0, 2007,”
http://www.w3.org/TR/wsdl20/
[22] OASIS, “UDDI Spec Technical Committee, UDDI Version 3.0.2,”
http://www.uddi.org/pubs/uddi_v3.htm
[23] W3C, ”SOAP Version 1.2 2007,” http://www.w3.org/TR/soap12-part1/
[24] Microsoft, ”Windows Server 2003 UDDI Services,”
http://uddi.microsoft.com/
[25] NOVELL, “Develop with UDDI” http://developer.novell.com/uddi/
[26] Mike P. Papazoglou, “ Service-Oriented Computing: Concepts,
Characteristics and Directions,” The IEEE Fourth International Conference
on Web Information Systems Engineering, pp.3-12, Dec. 2003.
[27] Aurélie Aurilla Bechina Arntzen, “Services Oriented Architecture:
integration requirements,” The 31st
Annual International Computer Software and Applications Conference, pp.24-27, July 2007.
[28] Young-Guk Ha, Joo-Chan Sohn and Young-Jo Cho, “Service-Oriented Integration of Networked Robots with Ubiquitous Sensors and Devices Using the Semantic Web Services Technology,” The International
Conference on Intelligent Robots and Systems, pp.3947-3952, Aug. 2005.
[29] Kyong-Ha Lee, Mi-young Lee, Yun-Young Hwang and Kyu-Chul Lee, ”A Framework for XML Web Services Retrieval with Ranking,” The
International Conference on Multimedia and Ubiquitous Engineering,
pp.773-778, April 2007.[30] Heqing Guan, Beihong Jin, Jun Wei, Wei Xu and Ningjiang Chen, “A
framework for application server based Web Services management,” The 12th
Asia-Pacific Software Engineering Conference, Page(s):8 pp. Dec. 2005.
[31] W3C, “OWL-S: Semantic Markup for Web Services,”
http://www.w3.org/Submission/OWL-S. 2004.
[32] Dumitru Romana, Uwe Kellera, Holger Lausena,etc., Web Service Modeling Ontology, applied ontololgy, 2005. 1(1): p. 77-106.
[33] W3c, “Web Service Semantics - WSDL-S. 2005,”
http://www.w3.org/Submission/WSDL-S/
[34] Kaijun Ran, Junqiang Song, Jinjun Chen, Nong Xiao and Cancan Liu, “A Pre-reasoning based Method for Service Discovery and Service Instance Selection in Service Grid Environments,” The IEEE Asia-Pacific Services
Computing Conference. Pp.320-327, Dec. 2007.
[35] K. Y. Lai, T. K. A. Phan and Z. Tari, “Efficient SOAP binding for mobile web services,” The IEEE Conference on Local Computer Netowrks, pp.
218-225, Nov.2005.
[36] Gehlen, G., Aijaz, F. and Walke, B., ”Mobile Web Service Communication Over UDP,” The IEEE 64th
Vehicular Technology Conference, pp.1-5, Sept.
2006.
[37] H. Combs, M. Gudgin, J. Justice, G. Kakivaya, D. Lindsey, D. Orchard, A.
Regnier, J. Schlimmer, S. Simpson, H. Tamura, D. Wright, and K. Wolf,
“SOAP-over-UDP,” Published on the internet, 2004. [Online]. Available:
http://msdn.microsoft.com/library/en-us/dnglobspec/html/soap-over-udp.pdf [38] M. Gudgin, M. Hadley, and T. Rogers, “Web Services Addressing 1.0-
Core,” Published on the internet, May 2006, w3C Recommendation. [Online].
Available: http://www.w3.org/TR/ws-addr-core/
[39] Tao Yu and Kwei-Jey Lin, “Service Selection Algorithms for Web Services with End-to-end QoS Constraints,” The IEEE International Conference on
E-commerce Technology, pp. 129-136, July. 2004.
[40] Algirdas Avizienis, Jean-Claud Laprie, Brian Randell and Carl Landwehr,
“Basic Concepts and Taxonomy of Dependable and Secure Computing,” The
IEEE Transactions on Dependable and Secure Computing, Vol. 1, No. 1,
pp.11-33, 2004[41] Vuong Xuan TRAN and Hidekazu TSUJI, “QoS based Ranking for Web Services: Fuzzy Approaches,” The 4th
International Conference in Next Generation Web Services Practices, pp.77-82, Oct. 2008.
[42] Lotfi A. Zadeh., “Fuzzy Sets,” In the journal of Information and Control, Elsevier Publisher, Vol. 8, No. 3, pp. 338-353. 1965
[43] M. Lin, J. Xie, H. Guo and H. Wang.,”Solving Qos-Driven Web Service Dynamic Composition as Fuzzy Constraint Satisfaction,” The IEEE
International Conference on E-Technology, E-Commerce and EService,
IEEE Computer Society, pp. 9–14, 2005
[44] P. Xiong and Y. Fan., “QoS-Aware Web Service Selection by a Synthetic Weight,” The 4th International Conference on Fuzzy Systems and Knowledge
Discovery, pp.632–637, 2007.
[45] M. F. Chen, G. H. Tzeng, and C. G. Ding., “Fuzzy MCDM Approach to Select Service Provider,” The 12th IEEE International Conference on Fuzzy
Systems, IEEE Computer Society, pp. 572–577, 2003.
[46] Wang, P., Chao, K., Lo, C., Huang, C. and Li, Y., “A Fuzzy Model for Selection of QoS-Aware Web Services,” The 2006 IEEE international
Conference on E-Business Engineering, IEEE Computer Society, pp.
585–593, 2006.
[47] Yijun Yu, Juan Fernandez-Ramil, Jianguo Lu and Phil Yuan, “Comparing Web Services with other Software Components,” The IEEE International
Conference on Web Services, pp.388-397, July 2007.
[48] Su Myeon Kim, Marcel-Catalin Rosu, “A Survey of Public Web Services,”
ACM WWW 2004, May 17–22, New York, USA.
[49] Yan Li, Yao Liu, Liangjie Zhang, Ge Li, Bing Xie, Jiasu Sun, ”An
Exploratory Study of Web Services on the Internet, “ The IEEE International
Conference on Web Services, pp.380-387 July 2007.
[50] Holger Lausen, Thomas Haselwanter, “Finding Web Services, ” Aleph Web Services GbR April 18, 2007.
[51] Jianchun Fan, Subbarao Kambhampati, ” A Snapshot of Public Web Services,
“ SIGMOD Record, Vol. 34, No. 1, March 2005.
[52] Si Won Choi, Jin Sun Her, and Soo Dong Kim, ”Modeling QoS Attributes and Metrics for Evaluating Services in SOA Considering Consumers’
Perspective as the First Class Requirement,” The IEEE Asia-Pacific Services
Computing Conference, pp.389-405, Dec. 2007.
[53] Rong Hu, Jian-xun Liu, Zhu-hua Liao and Jie Liu, “A Web Service Matchmaking Algorithm Based on an Extended QoS Model,” The IEEE
International Conference on Networking, Sensing and Control, April 2008.
[54] Fang Fang Chua, Hao Yuan and Soo Dong Kim, “A Visualization
Framework for Web Service Discovery and Selection Based on Quality of Service,” The IEEE Asia-Pacific Services Computing Conference,
pp.312-319, Dec. 2007.
[55] Shiping Chen, John Zic, Kezhe Tang and David Levy, ”Performance
Evaluation and Modeling of Web Services Security,” The IEEE International
Conference on Web Services, pp.431-438, July 2007.
[56] Zhengping Wu and Alfred C. Weaver, “Using Web Services to Exchange Security Tokens for Federated Trust Management,” The IEEE International
Conference on Web Services, pp.1176-1178, July 2007.
[57] OASIS, “Security Assertion Markup Language (SAML),”
http://xml.coverpages.org/saml.html
[58] OASIS, “Extensible Access Control Markup Language (XACML),”
http://xml.coverpages.org/xacml.html
[59] JIAN-XIN LI, BIN LI, LIANG LI and TONG-SHENG CHE, “A Policy Language for Adaptive Web Services Security Framework,” The Eighth
ACIS International Conference on Software Engineering, Artificial
Intelligence, Networking, and Parallel/Distributed Computing, pp.261-266,
July 2007.[60] Navya Sidharth and Jigang Liu, “IAPF: A Framework for Enhancing Web Services Security,” The 31st Annual International Computer Software and
Applications Conference, pp.23-30, July 2007.
[61] Vipin Singh Mewar, Subhendu Aich and Shamik Sural, ”Access Control
Model for Web Services with Attribute Disclosure Restriction,” The Second
International Conference on Availability, Reliability and Security,
pp.524-531, April 2007.
[62] Junqi Zhang, Yan Wang and Vijay Varadharajan, “Mobile Agent and Web Service Integration Security Architecture,” The IEEE International
Conference on Service-Oriented Computing and Applications, June 2007.
[63] LORI DELOOZE US Naval Academy, “Providing Web Service Security in a Federated Environment” Security & Privacy Magazine 2007
[64] C. Gutiérrez, E. Fernández-Medina and M. Piattini, “PWSSec: Process for Web services Security,” The IEEE international Conference on Web Services, pp.213-222 Sept.2006.
[65] Witold Abramowicz, Monika Kaczmarek and Dominik Zyskowski, “Duality in Web Services Reliability,” The Advanced International Conference on
Telecommunications and International Conference on Internet and Web Applications and Services, Feb.2006.
[66] Hangjung Zo, Derek L. Nazareth and Hemant K. Jain, ” Measuring
Reliability of Applications Composed of Web Services,” The 40th Hawaii
International Conference on System Sciences, Jan. 2007.
[67] Pat. P. W. Chan, Michael R. Lyu and Miroslaw Malek, ”Reliable Web Services: Methodology, Experiment and Modeling,” The IEEE International
Conference on Web Services, pp.679-686, July 2007.
[68] Fu-Chiung Cheng, Tai-Chang Hung , Young-Jang Chiou and Te-Chun Chang, “Design and Implementation of Web Service Integration Tool,” The
IEEE International Workshop on Service-Oriented System Engineering,
pp.91-96, Oct. 2005.[69] Hrushikesha Mohanty, Jitesh Mulchandani, DeepakChenthati and R. K.