Comparison of satellite and cellular architectures for downlink broadcast data transmission

Traditional voice and video‐oriented networks such as the cellular and satellite networks are being increasingly used to carry data traffic. We endeavour to compare the downlink broadcast performance of the two architectures against each other on the basis of energy consumption, end‐to‐end delay and maximum stable throughput. The architectures are modelled as systems of Geo/G/1 queues. Queuing theory arguments and then sample‐path based comparisons are used to show that the satellite architecture while being more energy‐efficient has a higher delay and a lower maximum throughput. The variation of energy and delay with the total number of receiver nodes is also studied. Copyright © 2006 John Wiley & Sons, Ltd.     

基于DC-net的会议室电子选举方案

提出了一种新的适用于小规模选举活动的电子选举方案,其最大特点是能够提供无条件的完美选票秘密性保障。方案具有自计票功能,能够实现公平性和可验证性。敌手对选举结果的破坏等同于解离散对数问题。该方案建立在DC-net匿名广播协议基础之上,其安全性不依赖于任何信任中心,但需假定任意投票者之间存在秘密信道。     

A Five-Phase Reservation Protocol (FPRP) for Mobile Ad Hoc Networks

A new single channel, time division multiple access (TDMA)-based broadcast scheduling protocol, termed the Five-Phase Reservation Protocol (FPRP), is presented for mobile ad hoc networks. The protocol jointly and simultaneously performs the tasks of channel access and node broadcast scheduling. The protocol allows nodes to make reservations within TDMA broadcast schedules. It employs a contention-based mechanism with which nodes compete with each other to acquire TDMA slots. The FPRP is free of the hidden terminal problem, and is designed such that reservations can be made quickly and efficiently with negligible probability of conflict. It is fully-distributed and parallel (a reservation is made through a localized conversation between nodes in a 2-hop neighborhood), and is thus scalable. A multihop ALOHA policy is developed to support the FPRP. This policy uses a multihop, pseudo-Bayesian algorithm to calculate contention probabilities and enable faster convergence of the reservation procedure. The performance of the protocol, measured in terms of scheduling quality, scheduling overhead and robustness in the presence of nodal mobility, has been studied via simulations. The results showed that the protocol works very well in all three aspects. Some future work and applications are also discussed.     

Android广播机制安全性研究

近年来,Android组件的安全性是研究热点,但作为Android四大组件之一的广播接收器,则鲜见有关其安全性的研究成果。在研究Android广播机制的基础上,对其安全结构与特点进行了深入分析。基于Android广播机制的安全挑战,针对性地给出相应的安全对策。最后,总结并展望今后的研究方向。     

Towards Designing a Trusted Routing Solution in Mobile Ad Hoc Networks

Designing a trusted and secure routing solution in an untrustworthy scenario is always a challenging problem. Lack of physical security and low trust levels among nodes in an ad hoc network demands a secure end-to-end route free of any malicious entity. This is particularly challenging when malicious nodes collude with one another to disrupt the network operation. In this paper we have designed a secure routing solution to find an end-to-end route free of malicious nodes with collaborative effort from the neighbors. We have also extended the solution to secure the network against colluding malicious nodes, which, to the best of our knowledge, is the first such solution proposed. We have also proposed a framework for computing and distributing trusts that can be used with out trusted routing protocol. Our proposed framework is unique and different from the other schemes in that it tries to analyze the psychology of the attacker and quantifies the behavior in the computational model. Extensive simulation has been carried out to evaluate the design of our protocol. Partially funded by Department of Defense Award No. H98230-04-C-0460, Department of Transportation Project No. FL-26-7102-00 and National Science Foundation Grant Nos. ANI-0123950 and CCR-0196557. Tirthankar Ghosh is a PhD candidate in the Telecommunications and Information Technology Institute at Florida International University. His area of research is routing security and trust computation in wireless ad hoc and sensor networks. He received his Bachelor of Electrical Engineering from Jadavpur University, India and Masters in Computer Engineering from Florida International University. Dr. Niki Pissinou received her Ph.D. in Computer Science from the University of Southern California, her M.S. in Computer Science from the University of California at Riverside, and her B.S.I.S.E. in Industrial and Systems Engineering from The Ohio State University. She is currently a tenured professor and the director of the Telecommunication & Information Technology Institute at FIU. Previously Dr. Pissinou was a tenured faculty at the Center for Advanced Computer Studies at the University of Louisiana at Lafayette where she was also the director of the Telecommunication & Information & Technology Laboratory partially funded by NASA, and the co-director of the NOMAD: A Wireless and Nomadic Laboratory partially funded by NSF, and the Advanced Network Laboratory. Dr. Pissinou is active in the fields computer networks, information technology and distributed systems. Dr. Kami (Sam) Makki has earned his Ph.D. in Computer Science from the University of Queensland in Brisbane Australia, his Masters degree in Computer Science and Engineering from the University of New South Wales in Sydney Australia, and his Bachelor and Masters Degrees in Civil Engineering from the University of Tehran Iran. Before joining the department of Electrical Engineering and Computer Science at the University of Toledo he has held a number of academic positions and research appointments at the Queensland University of Technology in Brisbane, Royal Melbourne Institution of Technology in Melbourne and at The University of Queensland in Brisbane Australia. He is an active researcher in the fields of distributed systems, databases, mobile and wireless communications, and has more than 30 publications in peerreviewed journals and international proceedings. He has served as a chair and technical program committee member and reviewer for a number of IEEE and ACM sponsored technical conferences and has received a number of achievement awards.     

电视剧缩编网络的研究与设计

介绍了电视剧缩编网络的需求与功能,分析了系统的主要业务流程,构建一个面向电视台全台网的电视剧缩编网络,实现了电视剧入库、上载、检索、编辑、播出、存档一体化管理等功能。     

移动应用安全批量化检测关键问题探讨

结合运营商应用商城业务运营安全需求,分析了移动应用安全检测存在的主要问题,提出了移动应用安全批量化检测的体系框架,阐述了架构实施过程中的各项关键问题,最后,给出了安全检测服务平台建设策略.     

Adaptively secure hierarchical identity-based signature in the standard model

Hierarchical identity-based signature(HIBS)has wide applications in the large network. However, the existing works cannot solve the trade-off between the security and efficiency. The main challenge at present is to construct a high efficient and strong secret HIBS with a low computation cost. In this paper, a new construction of HIBS scheme is proposed. The new scheme achieves the adaptive security which is a strong security in the identity-based cryptography. But our scheme has short public parameters and the private keys size shrinks as the hierarchy depth increases. The signature size is a constant and the cost of verification only requires four bilinear pairings, which are independent of hierarchy depth. Furthermore, under the q-strong computational diffie-Hellman problem(q-SDH)assumption, the scheme is provably secure against existential forgery for adaptive chosen message and identity attack in the standard model.     

保密传真通信系统的仿真实现

实际的保密传真通信系统是一个功能结构复杂的系统。在建立新系统前,通常需要对系统进行建模和仿真以消除系统中潜在的瓶颈,提高系统成功的概率。文中在分析了保密传真通信系统的工作原理之后,对保密传真通信系统的信源编码模块、加解密模块和调制解调模块进行了Matlab仿真实现,仿真结果达到了预期目标。     

非编网络化制播系统的设计与实现

根据浙江民生休闲频道非编网络制播系统的特点,介绍该系统的总体业务流程、体系结构、重要设备组成、网络安全管理,对系统关键技术及创新设计进行了详细的阐述,并对该系统今后的发展前景作了展望。