根據歸納，有三個問題會影響到情境感知應用程式(Context-aware application)執行的可靠度，第一個問題是當情境感知應用程式執行時，因為缺陷所造成最終狀態的不可達，第二個問題是因為有限資源所造成促動器(Actuator)的超載使用，這將使得情境感知應用程式執行失敗或執行品質降低，第三個問題是當多個情境感知應用程式執行時，由於彼此資源搶奪可能會產生死結問題而導致情境感知應用程式無法達成使用者需求，但目前仍沒有完善的驗證機制用以避免上述問題，因此本論文將針對這三個問題提出相對應的解決方法。
本論文為了分析上述問題，以服務品質需求觀點的品質驅動派翠網(Quality-driven Petri Net, QPN)來建立多個情境感知應用程式執行流程之模型，並根據QPN基礎提出一個驗證方法來驗證執行流程的可靠度，本方法是經由期望狀態的可達計算、超載偵測與死結的分析來驗證此模型的可靠度。
本篇論文所開發的驗證器(Context-aware QPN-based Validator, CQV)可以提供使用者利用QPN來建立模型，進而驗證目前所有情境感知應用程式執行的可靠度，最後經由設計規畫，映射至實際例子來說明。

Three major problems may affect the reliability of context-aware applications. The first problem is that the expected status of context-aware applications may be not reacha-ble. Secondly, the overloading actuators may lead to the unexpected failure or degrade the quality of context-aware applications because of the limited resources. Finally, the resource preemption among context-aware applications may lead to the deadlock. Then, it will cause that context-aware applications can not achieve users’ requirements. However, there are still no mature validation approaches to prevent such problems. In this paper, a validation approach based on a Petri net is proposed to solve these problems.
To analyze these problems, the workflow of multiple context-aware applications is modeled by Quality-driven Petri Net (QPN). On the basis of QPN, we propose an ap-proach for validating the reliability of the workflow.
In this paper, Context-aware QPN-based Validator (CQV) that we developed can help users model the workflow of multiple context-aware applications. Through the mod-el, the reliability of multiple context-aware applications is validated. Finally, we design and plan a study case to illustrate the physical process of multiple context-aware applica-tions.

[1] Salah Aly and Khaled Mustafa, “Protocol Verification and Analysis Using Colored
Petri Nets”, Technical Report, 2003.
[2] Vikas Agarwal, Koustuv Dasgupta, Neeran Karnik, Arun Kumar, Ashish Kundu,Sumit
Mittal, and Biplay Srivastava, “A Service Creation Environment Based on End to End Composition of Web Service”, in Proceedings of the 14st international confer-ence on World Wide Web, SESSION: Web Services, ACM Press, Chiba, Japan, 2005, pp 128 - 137.
[3] Boualem Benatallah, Marlon Dumas, Quan Z. Sheng and Anne H.H Ngu, “Declartive
Composition and Pear-to-Pear Provisioning of Dynamic Web Services”, in proceeding of the 18th international Conference on Data Engineering(ICDE’02), IEEE Computer Society, 2002.
[4] Matthias Baldauf, Schahram Dustdar* and Florian Rosenberg, “A Survey on Con
text-aware system,” Technical University of Vienna Information System Institute Distributed System Group, 2007.
[5] CPNTOOLS, Available: http://wiki.daimi.au.dk/cpntools/cpntools.wiki
[6] R. Scctt Cost, Ye Chen, Tim Finin, Yannis Labrou and Yun Peng, “Using Colored
Petri Nets for Conversation Modeling”, Lecture Notes in Computer Science, Vol. 1916 , Issues in Agent Communication, pages 178 - 192, Springer - Verlag , 2000.
[7] Yü-Liang Ch'i and Chih-Wei Li, “A Validating Approach for Evaluating Reliability of
Web Services Compositions” Journal of Information, Technology and Society, Vol. 5, No. 2, 2005.
[8] Allan Cheng, Javier Esparza and Jens Palsberg, “Complexity Results for 1-safe Nets”,
Foundations of software technology and theoretical computer science, volume 761 of Lecture Notes in Computer Science, pages 326—337, Springer-Verlag, Berlin, 1993.
[9] Design/CPN, 2006, Available: http://www.daimi.au.dk/designCPN/
[10] finite state machine, Available: http://www.nist.gov/dads/HTML/finiteStateMachine.html
[11] Eric Garcia, Julien Henriet and Jean-Christophe Lapayre, “Modeling the Chameleon
Using a Colored-Petri Net: Proof and Validation”, Technical Report, LIFC, 2005.
[12] Rachid Hamadi and Boualem Benatallah, “A Petri Net-based Model for Web Service
Composition”, in Proceedings of the 14th Australasian Database Conference, vol. 17, Australian Computer Society, Inc, Adelaide Australia, 2003, pp 191 - 200.
[13] Jade - Java Agent DEvelopment Framework, Available: http://jade.tilab.com/
[14] Kevin Mcleish, Introduction to Petri Net, Available: http://www.cse.fau.edu/~maria/COURSES/CEN4010-SE/C10/10-7.html
[15] Tadao Murata, “Petri Nets: Properties, Analysis and Applications”, in Proceedings of
the IEEE, Vol. 77, issue 4, 1989, pp. 541 - 580.
[16] Srini Narayanan and Sheila A. Mcllraith, “Simulation, Verification and Automated
Composition of Web Services”, in Proceedings of the 11st international conference on World Wide Web, SESSION: Semantic Web Services (WWW’02), ACM Press, Ho-nolulu, Hawaii, USA, 2002, pp. 77 - 88.
[17] Pi-calculus, Available: http://www.ebpml.org/pi-calculus.htm
[18] Petri Nets World, Available: http://www.informatik.uni-hamburg.de/TGI/PetriNets/
[19] Abraham Silberschatz, Peter Baer Galvin and Greg Gagne and A Silberschatz,
Opeating System Concepts 6th Edition (Hardcover), Wiley, 2001
[20] Yujin Song and Jongkun Lee, “Deadlock Analysis of Petri Nets Using the Transitive
Matrix”, in Proceedings of the 41st SICE Annual Conference, Vol. 2, 2002, pp 689 - 694.
[21] Biplav Srivastava and Jana Koehler, “Web Service Composition – Current Solutions
and Open Problems”, ICAPS 2003 Workshop on Planning for Web Services, 2003.
[22] David Skogan, Roy Gronmo, Ida Solheim, “Web Services Composition in UML”, in
proceedings of the 8th IEEE Enterprise Distributed Object Computing Confe-rence(EDOC 2004), IEEE Computer Society, 2004.
[23] Danny Weyns and Tom Holvoet, “A Colored Petri Net for a Multi-Agent Applica-
tion”, SiteSeer, 2002.
[24] Michael Wooldridge, An Introduction to MultiAgent Systems, Wiley, 2002.
[25] Ying-Han Ye and Yau-Hang Kuo, “Development of A Multi-agent Software Plat-
form for Context-aware Digital Home Applications and Its Environment Simulator”, Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan, ROC, 2006.
[26] R Zurawski and MengChu Zhou, “Petri nets and industrial applications: A tutorial”,
IEEE Transactions on Industrial Electronics, Vol. 41, No. 6, pp. 567 - 583, 1994.