近年來，汽機車數量持續上升，不僅容易造成交通壅塞，也是導致溫室氣體排放量逐年升高的重大因素之一。
節能智慧型運輸系統不但結合車用行動通訊網路（Vehicular Ad-hoc Network，VANET），在交通載具與路側單元間（Road Side Unit，RSU）建構一無線通訊網路，且透過與雲端運算系統之訊息交換來改善行車效率及降低道路交通瓶頸。
本論文重點在於路側單元(RSU)內中介軟體之開發，我們將開發路側單元內中介軟體之以下關鍵模組：訊息收送與處理，交通事件判別及警告系統，交通號誌控制策略與遠端RSU管理。開發之路側單元負責與車輛，雲端交通控制中心，以及其它路側單元間進行交通訊息之傳遞與處理，且附有交通事件判別與警告系統來通知駕駛是否有緊急事件之發生及地點，在一般道路上，一旦有車禍等緊急事件發生，有可能影響交通，進而造成阻礙車流之順暢，路側單元可透過交通事件判別及警告系統提早通知駕駛者，讓駕駛們提早做準備。此外，RSU並根據交通狀況控制交通號誌，以維持道路行駛的順暢性，也可透過遠端的方式管理RSU。
最後，我們已經在嵌入式平台Pandaboard ES上完成RSU的實作，並且實測RSU在Pandaboard ES上與OBU及雲端交控中心進行訊息傳遞。我們也測試了RSU的交通事件判別及警告系統、RSU處理能力及系統耐久度，實驗結果RSU在有交通事件判別及警告系統時可提早讓模擬的OBU知道緊急事件的情形。在RSU的處理能力的實驗中，實驗結果顯示RSU可同時處理多達五千台以上模擬的OBU，在系統耐久度方面，RSU持續運作超過一個月後仍可正常運作。

In recent years, the increasing number of vehicles has become one of the main contributors to the increased emissions of greenhouse gas in addition to the associated traffic congestion.
The Green ITS adopted Vehicular Ad-hoc Network (VANET) techniques to construct wireless networks among and between vehicles and Road Side Units (RSU) and also to communicate with cloud computing technology in order to improve traffic conditions.
This paper is aimed at to developing middleware for a Road Side Unit (RSU). In this paper, the development of the core modules of the middleware inside an RSU is discussed. The modules to be developed include communication management, the traffic event identification and warning system, traffic policy management and remote management. An RSU transmits traffic-related messages to vehicles, the cloud computing system and other neighboring RSUs. It also has traffic-event identification and warning system to warn drivers about emergency events and locations. On the road, when a traffic accident or emergency event occurs, it may affect an entire intersection and reduce driving efficiency. RSUs can provide an early warning to drivers by used this traffic event identification and warning system. In addition, RSUs also control the traffic signals according to the traffic conditions and can also be managed by a remote client.
Finally, the implemented RSU is ported to an embedded platform Pandaboard ES. We test the communication performance between the RSU and OBU (on board unit) and also test the communication performance between the RSU and the cloud control center. We test the traffic event identification and warning system as well as the handling ability and durability of the RSU. The experimental results showed that the RSU can provide and early warning to a simulated OBU about an emergency event used the traffic event identification and warning system. The experimental results for the handling ability and durability of the RSU indicated that the RSU can handle more than 5000 simulated OBUs at the same time and works fine for more than a month.

[1] K. Mershad and H. Artail, “SCORE: Data Scheduling at Roadside Units in Vehicle Ad Hoc Networks,” International Conference on Telecommunications (ICT), 2012, pp. 1-6.
[2] I. Filippini, F. Malandrino, G. D´an, M. Cesana, C. Casetti and I. Marsh, “Non-cooperative RSU Deployment in Vehicular Networks,” Annual Conference on Wireless On-demand Network Systems and Services (WONS), Jan. 2012, pp. 79-82.
[3] G. G. Md. N. Ali, E. Chan and W. Li, “On Scheduling Real-time Multi-item Queries in Multi-RSU Vehicular Ad Hoc Networks (VANETs),” International Conference on Advanced Information Networking and Applications Workshops (WAINA), March. 2013, pp. 7-13.
[4] A. Gupta and V. Lokhande, “Intelligent Traffic Obstruction Control and Supervision System in VANET,” International Conference on Networks & Soft Computing (ICNSC), Aug. 2014, pp. 40-45.
[5] A. Abdrabou, B. Liang, and W. Zhuang, “Delay Analysis for a Reliable Message Delivery in Sparse Vehicular Ad Hoc Networks,” IEEE Global Telecommunications Conference, Dec. 2010, pp. 1-5.
[6] C. Campolo and A. Molinaro, “On Vehicle-to-Roadside Communications in 802.11p/WAVE VANETs,” IEEE International Conference on Wireless Communications and Networking, Mar. 2011, pp. 1010-1015.
[7] X. Jin, W. Su, and Y. Wei, “Quantitative Analysis of the VANET Connectivity: Theory and Application,” IEEE 73rd Vehicular Technology Conference, May 2011, pp. 1-5.
[8] C. L. Chang and J. R. Luo, “The Scheduling Algorithm in Road Side Unit for Vehicular Ad Hoc applications,” International Computer Symposium, Dec. 2010, pp. 85-90.
[9] Y. Peng, Z. Abichar, and J. M. Chang, “Roadside-Aided Routing (RAR) in Vehicular Networks,” The IEEE International Conference on Communications, Jun. 2006, pp. 3602-3607.
[10] M. Shahverdy, M. Fathy, and S. Yousefi, “Scheduling Algorithm for Vehicle to Road-Side Data Distribution,” Communications in Computer and Information Science, 2010, pp. 22-30.
[11] S. Sahebgharani and M. Shahverdy, “A Scheduling Algorithm for Downloading Data from RSU Using Multicast Technique,” 2012 Ninth International Conference on Information Technology New Generations (ITNG), April 2012,pp. 809-814.
[12] J. Wu, A. Abbas-Turki, and A. EL Moudni, “Discrete Methods for Urban Intersection TrafficControlling,” IEEE International on Vehicular Technology Conference, Apr. 2009, pp. 1-5.
[13] L. Le, F. Baldessari and W. Zhang, ”Vehicular Wireless Short-range Communication for Improving Intersection Safety,” IEEE Communications Magazine, Vol. 47, 2009, pp. 104-110.
[14] J. L. Shieh, C. Y. Lu and W. H. Lee, “VANET-based Coordinated Signal Control in a Local Network for Minimizing CO2 Emissions and Fuel Consumption,” 9th International Conference on Computing Technology and Information Management (NCM, ICNIT), Jun. 2013.
[15] W. H. Lee, Y. C. Lai, and P. Y. Chen, “A Study on Energy Saving and CO2 Emissions Reduction on Signal Countdown Extension by Vehicular Ad-Hoc Network,” IEEE Transactions on Vehicular Technology, Vol. 64, No. 3, pp. 890-900, Feb. 2014.
[16] T. Rye, “Intelligent Transportation Systems,” “http://transportlearning.net/competence/docs/ITS%20Telematics.pdf”
[17] S. K.C. Lo, “A Collaborative Multi-Agent Message Transmission Mechanism in Intelligent Transportation System – A Smart Freeway Example,” Information Sciences, Vol. 184, No. 1, pp. 246-26, Feb.2012.
[18] T. Winters, M. Johnson, and V. Paruchuri, “LITS: Lightweight Intelligent Traffic Simulator,” International Conference on Network-Based Information Systems, Aug. 2009, pp. 386-390.
[19] E. Azimirad, N. Pariz, and M. B. N. Sistani, “A Novel Fuzzy Model and Control of Single Intersection at Urban Traffic Network,” IEEE Systems Journal, Vol. 4, No.1, Mar. 2010, pp. 107-111.
[20] B. Zhou, J. Cao, and H. Wu, “Adaptive Traffic Light Control of Multiple Intersections in WSN-Based ITS,” The IEEE 73rd on Vehicular Technology Conference, May 2011, pp. 1-5.
[21] B. Zhou, J. Cao, X. Zeng, and H. Wu, “Adaptive Traffic Light Control in Wireless Sensor Network-Based Intelligent Transportation System,” The IEEE 72nd Vehicular Technology Conference,Sept. 2010 pp. 1-5, 6-9.
[22] X. H. Yu and A. R. Stubberud, “Miarkovian Decision Control for Traffic Signal Systems,” The 36 th conference on Decision & Control, San Diego, California USA, Dec. 1997, pp. 4782-4787.
[23] J. Y. Li, X. Pan, and X. Q. Wang, “State-Space Equations and the First-Phase Algorithm for Signal Control of Single Intersections,” Tsinghua Science & Technology, Vol. 12, No. 2, pp. 231-235, Apr. 2007.
[24] N. Maslekar, M. Boussedjra, J. Mouzna, and H.Labiod, “VANET Based Adaptive Traffic Signal Control,” The IEEE 73rd Vehicular Technology Conference, 15-18 May 2011, pp. 1-5.
[25] J. Zhou, X. Zhou, Z. Chen, and X. Chen, “Research of Real-Time Control Algorithm for Traffic Lights Based on CPU Process Scheduling,” IEEE International Conference on Anti-Counterfeiting,Security and Identification, Jun. 2011, pp. 110-114. [26] V. Gradinescu, C. Gorgorin, R. Diaconescu, V. Cristea, and L. Iftode, “Adaptive Traffic Lights Using Car-to-Car Communication,” IEEE 65th Conference on Vehicular Technology , Apr. 2007, pp. 21-25.
[27] H. Kowshik, D. Caveney, and P. R. Kumar, “Provable Systemwide Safety in Intelligent Intersections,” IEEE Transactions on Vehicular Technology, Vol. 60, No. 3, Mar. 2011, pp. 804-818.
[28] A. Wegener, H. Hellbruck, and C. Wewetzer, “VANET Simulation Environment with Feedback Loop and its Application to Traffic Light Assistance,” IEEE International Workshop on GLOBECOM, Nov. 2008, pp. 1-7.
[29] J. Jakubiak and Y. Koucheryavy, “State of the Art and Research Challenges for VANETs,” IEEE International Conference on Consumer Communications and Networking, Jan. 2011, pp. 912-916.
[30] I. Salhi, M. O. Cherif, and S. M. Senouci, “A New Architecture for Data Collection in Vehicular Network,” The IEEE International Conference on Communications, Jun. 2009, pp. 1-6.
[31] F. Zhang, J. Hao, and S. Li, “Traffic Information Aggregation and Propagation Scheme for VANET in City Environment,” The 3rd IEEE International Conference on Broadband Network and Multimedia Technology, Oct. 2010, pp. 619-623.
[32] S. Yousefi, E. Altman, R. El-Azouzi, and M. Fathy, “Analytical Model for Connectivity in Vehicular Ad Hoc Networks,” IEEE Transactions on Vehicular Technology,Vol. 57, No. 6, Nov. 2008, pp. 3341-3356.
[33] J. Toutouh and E. Alba, “An Efficient Routing Protocol for Green Communications in Vehicular Ad-hoc Networks,” The ACM International Conference on Genetic and Evolutionary Computation, Jul. 2011, pp. 719-726.
[34 ] Json-c , “ https://github.com/json-c/json-c/wiki”.
[35] Curl , “http://curl.haxx.se/”.
[36] OMAPTM 4 PandaBoard System Reference Manual,
“http://pandaboard.org/sites/default/files/board_reference/pandaboard-ea1/panda-ea1-manual.pdf”.