基于COMGIS的城市居住小区道路交通噪声预测系统的研制

介绍了基于COMGIS的城市居住小区道路交通噪声预测系统的设计和实现。在Microsoft VisualC中嵌入GIS控件MapX作为开发环境，结合GIS和MIS的相关理论和技术，完成了对系统的初步开发。     

网络监控系统的设计与实现

介绍了网络监控系统的设计思想和实现方法。系统提供流量监控、拓扑发现、故障管理等功能，可以有效地监控流量及其他网络异常情况。     

光网络流量工程优化计算的适应度函数研究

研究了光网络流量工程优化计算中的适应度函数，其实质是为相互制约的多个单目标寻找一个合理的综合评价的数学表达式。使用了主分量分析的方法，该方法可以消除多个单目标之间的相互制约的关系、信息重叠以及量纲的差异，可以计算出综合评价的有效的数学表达式。仿真试验表明，该方法是可行的。     

城市主干道交叉口交通流的模糊控制

城市主干道的交通效率,从整体上影响着整个城市的交通运作效率。该文以城市中心地带主干道交叉路口为对象,进行了交通流的模糊控制研究,提出的基于闭环模糊控制算法的智能化控制策略,有效地提高了主干道交叉口相关区域内的道路使用率。     

行驶车辆磁感应检测及智能道路传感系统

智能运输系统的前提条件之一是实现道路行驶车辆自动检测与交通信息实时采集。详细分析了磁感应式行驶车辆检测工作原理,建立了道路交通流信息计算模型,完成了基于DSP技术的智能检测系统设计与实现,采取了软硬件综合技术来对付现场各种干扰与噪声信号。对试验结果进行了分析,实际测试表明:系统性能稳定可靠。     

基于MPEG-4 FGS的视频流量模型

目前MPEG-4精细颗粒度可伸缩性(Fine Graruldty Scalability，FGS)编码视频正成为视频流服务的一种主要的业务流，因此，针对MPEG-4FGS视频流量进行建模对于网络性能仿真和通信网络设计具有十分重要的意义。该文首先介绍了MPEG-4FGS编码原理，然后对MPEG-4FGS视频流量的统计特性进行了分析，在此基础上，提出了基于MPEG-4FGS的视频流量模型。实验结果表明，该模型能较好地拟合原视频帧序列大小，且能根据网络带宽的动态变化进行适应的码率分配。     

A MAC Protocol for Multimedia Traffic in Slotted CDMA Wireless Communication Systems

In this paper, a media access control (MAC) protocol is proposed for multimedia traffic in slotted CDMA wireless communication systems. The channel resource is partitioned into four compartments: video, voice and data compartments, and common resource pool (CRP) which can be used by either voice or data. Video is only permitted to use its pre-allocated channels. Besides assigning voice to its own compartment, a threshold type decision policy is introduced to regulate voice call admission control in CRP. Data can use not only data and CRP compartments, but also the idle capacity of both video and voice. The proposed protocol provides a simple and flexible resource allocation decision for the multimedia traffic such that the bandwidth can be utilized efficiently while satisfying the quality of service (QoS) requirement for each traffic category. Two mathematical analysis methods are applied to evaluate the system performance. The first, Traditional Markov Analysis (TMA) is used to calculate the video and the voice blocking probabilities, and the second, Transient Fluid Analysis (TFA) is adopted to evaluate the average data delay and the channel utilization. Computer simulations verify the accuracy of mathematical models.Miao Ma received the B.Eng. and M.Eng. degrees in Electrical Engineering from Harbin Institute of Technology, China in 1992 and 1996, respectively, and the Ph.D degree in Electrical and Electronic Engineering from Nanyang Technological University, Singapore in 2003. She is a research scientist in the Institute for Infocomm Research in Singapore. Her research interests include network security, media access control, wireless communications and computer networking.Erry Gunawan received the B.Sc. degree in electrical and electronic engineering from the University of Leeds, U.K., in 1983 and the M.B.A. and the Ph.D. degrees, both from Bradford University, in 1984 and 1988, respectively. From 1984 to 1988, he was a Satellite Communication System Engineer at Communication Systems Research Ltd., Ilkley, U.K. In 1988, he moved to Space Communication (SAT-TEL) Ltd, Northampton, U.K. He joined the School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, in 1989, and currently, he is an Associate Professor in the same school. His research interests include the fields of digital communications, mobile and satellite communications, error coding, and spread spectrum. He has published over 60 international research papers and has been a consultant to a local company on the study of DECT system and BLUETOOTH.     

Grooming of Arbitrary Traffic in Optical WDM Mesh Networks Using a Genetic Algorithm

In this paper, a genetic algorithm is proposed for grooming of arbitrary traffic in optical mesh networks. Traffic streams are routed in the wavelength division multiplexing (WDM) grooming networks that comprise both fiber links and established lightpaths. Chromosomes are split into multiple versions when multiple shortest routes are found. The selection strategy is based on a comparison between chromosomes. A variety of cost functions are proposed for the routing algorithm and two comparison methods are considered in the selection procedure. Computer simulations are performed with randomly generated traffic patterns. The results show that the algorithm is effective for traffic grooming (TG) problems, and also for routing and wavelength assignment problems.     

Efficient Online Algorithms for Dynamic Shared Path Protection in WDM Optical Networks

In this work, we have proposed and studied efficient online algorithms for shared path protection under dynamic traffic conditions in survivable WDM optical mesh networks. Given a connection request, routing and wavelength assignment of a working path and a protection path for the request is formulated as two integer linear programs based on shared and dedicated path protection, respectively. The objective is to minimize the total cost of additional resources used by the working path as well as the protection path to accommodate a new connection request. We then devise two resource efficient online algorithms using pre-computed candidate routes. The first algorithm uses one candidate working path and one candidate protection path for each newly arrived connection request while the second algorithm may use multiple candidate working paths and/or multiple candidate protection paths. The selection of a pair of paths from candidate routes as well as the assignment of appropriate wavelengths to accommodate a connection request is then jointly considered to minimize the total cost of additional resources. The solutions to the ILP formulations serve as the baseline for evaluating the performance of the proposed algorithms. We have evaluated the effectiveness of the proposed online algorithms via extensive simulations in terms of the connection blocking probability and the revenue earnings improved over the dedicated path protection approach. Our simulations indicate that our proposed computationally efficient online algorithms are able to provide 100% restorability against single failures with a resource efficiency comparable to that of the optimal shared path protection. The results also show that a small increase in the number of candidate working paths or protection paths (from 1 to 3) provides better performance, but a further increase does not improve the performance significantly. Therefore, a proper balance can be struck to achieve both satisfactory performance and efficient computation.The work reported in this paper was supported in part by AFRL, the U.S. Department of Energy Early Career Award DE-FG02-03ER25580, and a DAGSI graduate scholarship. Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the funding agencies.