節點叢集化是一套古典的網路節點管理方式，藉由將節點叢集的方式可以幫助凌亂複雜的網路結構形成一套階層化的管理架構。在叢集架構中傳輸訊息時，可藉由位於階層頂端的叢集管理節點快速的將欲傳輸訊息散播出去，達到有效的網路訊息傳輸，本研究內容即是提出一套適合用於車載網路（VANET）交叉路口環境的叢集化方法。由於車載網路中的節點移動速率較一般無線網路存在的節點（例如：手持裝置、筆電）快速，且於真實道路環境通常具有交叉路口拓樸，並且存在利用紅綠燈去控制整體環境中車輛流動的特性，而以往在車載網路上的節點叢集方法其環境大部分位於高速公路長直道路之上，故本研究的主要考量在於需引入哪一些額外的環境已知訊息去代替原先固有的節點叢集方法，促使其符合交叉路口所具有的節點移動特性，並讓形成的叢集架構在經過移動之後不致於太快遠離其所屬叢集管理節點或是控管成員節點的傳輸範圍之外，加強叢集內節點之間的連線穩定性。研究最後將透過模擬驗證其穩定性指標，進一步證明此節點叢集方法之效能以及不同參數對於此方法之影響。

Using clustering technologies to manage nodes in a network is a classical and conventional approach. Node clustering is capable of arranging a network into a hierarchical structure that is tractable upon the requirements of management and maintenance of nodes in dynamic networks, where messages can be broadcast rapidly and efficiently by cluster-head nodes at the top of the hierarchy. The research in this thesis proposed an efficient clustering scheme at crossroads in vehicular ad-hoc network environments. Since nodes in vehicular networks have higher motion speed than those in traditional mobile ad-hoc networks. In addition, node movements in vehicular networks are affected by crossroads as well as traffic lights in real road environments. Thus, the main goal of this clustering scheme is to understand which well-known information of vehicular environments can help vehicular nodes to do clustering in a cost-effective manner corresponding to the surrounding of a crossroads. So that, vehicular nodes can form in a number of stable clusters that are not volatile and dismissed without frequently changes of cluster nodes. Finally, the simulation is employed to inspect the stability and robustness of the proposed scheme. Simulation results show that this scheme is able to avoid futile clustering around a crossroad with traffic lights, thereby reduce the cost of cluster organization in vehicular network environments.

[1] Peng Fan, James Haran, John Dillenburg, and Peter Nelson, “Cluster-Based Framework in Vehicular Ad-Hoc Networks,” Lecture Notes in Computer Science, vol. 3738, pp. 32-42, 2005.
[2] Evandro Souza, Ioanis Nikolaidis, and Pawel Gburzynski, “A New Aggregate Local Mobility Clustering Algorithm for VANETs,” Proc. IEEE International Conference on Communications (ICC), pp. 1-5, 2010.
[3] Prithwish Basu, Naved Khan, and Thomas D. C. Little, “A Mobility Based Metric for Clustering in Mobile Ad Hoc Networks,” Proc. International Conference Distributed Computing Systems Workshops, pp. 413-418, 2001.
[4] Slawomir Kuklinski, and Grzegorz, “Density Based Clustering Algorithm for VANETs, “ Testbeds and Research Infrastructures for the Development of Networks and Communities Workshops, vol. 19, pp. 1-6, 2009.
[5] Leandros A. Maglaras, Dimitrios Katsaros, “Distributed Clustering in Vehicular Networks,” Proc. Second International Workshop on Vehicular Communications and Networking in conjunction with IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), pp. 593-599, 2012.
[6] Stefano Basagni, “Distributed Clustering for Ad Hoc Networks,” Proc. International Symposium Parallel Architectures, Algorithms, and Networks (I-SPAN), PP. 310-315, 1999.
[7] Zhigang Wang, Lichuan Liu, MengChu Zhou, and Nirwan Ansari, “A Position-Based Clustering Technique for Ad Hoc Intervehicle Communication,” IEEE Transactions on Systems, Man, and Cybernetics-Part C: Applications and Reviews, vol. 38, pp. 201-208, 2008.
[8] Yu-Xuan Wang, and Forrest Sheng Bao, “An Entropy-Based Weighted Clustering Algorithm and Its Optimization for Ad Hoc Networks,” Proc. IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), pp. 56, 2007.
[9] Michel Daoud Yacoub, Fundamentals of Mobile Radio Engineering, CRC-Press, 1993.
[10] Nitin Maslekar, Mounir Boussedjra, Joseph Mouzna, and Houda Labiod, “C-DRIVE: Clustering Based on Direction in Vehicular Environment,” Proc. New Technologies, Mobility and Security (NTMS), pp. 1-5, 2011.
[11] Nitin Maslekar, Joseph Mouzna, Mounir Boussedjra, and Houda Labiod, “CATS: An Adaptive Traffic Signal System Based on Car-to-Car Communication,” Journal of Network and Computer Applications, vol.36, pp. 1-8, 2012.
[12] Yvonne Gunter, Bernhard Wiegel, and Hans Peter Grossmann, “Cluster-Based Medium Access Scheme for VANETs,” Proc. IEEE Intelligent Transportation Systems Conference, pp. 343-348, 2007.
[13] Christine Shea, Behnam Hassanabadi, and Shahrokh Valaee, “Mobility-Based Clustering in VANETs Using Affinity Propagation,” Proc. IEEE Global Telecommunications Conference (GLOBECOM), pp. 1-6, 2009.
[14] Nitin Maslekar, Joseph Mouzna, Houda Labiod, Manoj Devisetty, and Manohara Pai, “Modified C-DRIVE: Clustering Based on Direction in Vehicular Environment,” Proc. IEEE Intelligent Vehicles Symposium (IV), pp. 845-850, 2011.
[15] Grzegorz Wolny, “Modified DMAC Clustering Algorithm for VANETs,” Proc. International Conference on ystems and Networks Communications (ICSNC), pp. 268-273, 2008.
[16] Peng Fan, Prasad Sistla, and Peter Nelson, “Theoretical Analysis of a Directional Stability-Based Clustering Algorithm for VANETs,” Proc. ACM International Workshop on VehiculAr Inter-NETworking, pp. 80-81, 2008.
[17] Mohammad S. Almalag, and Michele C. Weigle, “Using Traffic Flow for Cluster Formation in Vehicular Ad-hoc Networks,” Proc. IEEE Local Computer Networks (LCN), pp. 631-636, 2010.
[18] Ameneh Daeinabi, Akbar Ghaffar Pour Rahbar, and Ahmad Khademzadeh, “VWCA: An Efficient Clustering Algorithm in Vehicular Ad Hoc Networks,” Journal of Network and Computer Applications, vol. 34, pp. 207-222, 2011.
[19] Mainak Chatterjee, Sajal K. Das, and Damla Turgut, “WCA: A Weighted Clustering Algorithm for Mobile Ad Hoc Networks,” Cluster Computing, vol. 5, pp. 193-204, 2002.
[20] Ehssan Sakhaee, and Abbas Jamalipour, “A New Stable Clustering Scheme for Pseudo-Linear Highly Mobile Ad Hoc Networks,” Proc. IEEE Global Telecommunications Conference (GLOBECOM), pp. 1169-1173, 2007.
[21] Khalid Abdel Hafeez, Lian Zhao, Zaiyi Liao, and Bobby Ngok-Wah Ma, “A Fuzzy-Logic-Based Cluster Head Selection Algorithm in VANETs,” Proc. IEEE International Conference on Communications (ICC), pp. 203-207, 2012.
[22] Fan Li, and Yu Wang, “ Routing in Vehicular Ad Hoc Networks: A Survey,” IEEE Vehicular Technology Magazine, vol. 2, pp. 12-22, 2007.
[23] Yun-Wei Lin, Yun-Shyan Chen, and Sing-Ling Lee, “ Routing Protocols in Vehicular Ad Hoc Networks: A Survey and Future Perspectives,” Journal of Information Science and Engineering, vol. 26, pp. 913-932, 2010.
[24] Brendan J. Frey, and Delbert Dueck, “ Clustering by Passing Messages Between Data Points,” Science, vol. 315, pp. 972-976, 2007.
[25] Wai Chen, Ratul K. Guha, Taek Jin Kwon, John Lee, and Yuan-Ying Hsu, “A Survey and Challenges in Routing and Data Dissemination in Vehicular Ad Hoc Networks,” Wireless Communications and Mobile Computing, vol. 11, pp. 787-795, 2011.
[26] Tomoyuki Ohta, Shinji Inoue, and Yoshiaki Kakuda, “An Adaptive Multihop Clustering Scheme for Highly Mobile Ad Hoc Networks,” Proc. International Symposium on Autonomous Decentralized Systems (ISADS), pp. 293-300, 2003.
[27] Mario Gerla, and Leonard Kleinrock, “Vehicular Networks and The Future of The Mobile Internet,” Computer Networks, vol. 55, pp. 457-469, 2011.
[28] Mario Gerla, and Jack Tzu-Chieh Tsai, “Multicluster, mobile, multimedia radio network,” Wireless Networks, vol. 1, pp. 255–265, 1995.
[29] Dennis John Baker and Anthony Ephremides, “ A distributed algorithm for organizing mobile radio telecommunication networks,” Proc. International Conference on Distributed Computer Systems, pp. 476–483, 1981.
[30] Nitin Maslekar, Mounir Boussedjra, Houda Labiod, and Joseph Mouzna, “A Stable Clustering Algorithm for Efficiency Applications in VANETs,” Proc. IEEE Wireless Communications and Mobile Computing Conference (IWCMC), pp. 1188-1193, 2011.
[31] Ossama Younis, Marwan Krunz, and Srinivasan Ramasubramanian, “Node Clustering in Wireless Sensor Networks: Recent Developments and Deployment Challenges,” IEEE Network, vol. 20, pp. 20-25, 2006.
[32] Abhay K. Parekh, “Selecting routers in ad-hoc wireless networks,” Proc. SBT/IEEE International Telecommunications Symposium, 1994.
[33] Dennis John Baker and Anthony Ephremides, “The architectural organization of a mobile radio network via a distributed algorithm,” IEEE Transactions on Communications, vol. 29, pp. 1694-1701, 1981.
[34] Anthony Ephremides, Jeffery E. Wieselthier and Dennis John Baker, “A design concept for reliable mobile radio networks with frequency hopping signaling,” Proceedings of the IEEE, vol. 75, pp. 56-73, 1987.