四通八达“一卡通”——记上海华虹计通智能卡系统有限公司

上海市民好时尚:市区出行手持一张小小公共交通卡,就能轻松乘坐公交车、出租车、地铁、轻轨和轮渡,方便潇洒,省时省力。上海公共交通的这一重大变革,使广大老百姓享受到了信息化时代的甜头,公交单位实现了电子售票和自动结算。这“一卡通”是如何诞生的?又将如何发展?日前,记者采访了华虹集团所属上海华虹计通智能卡系统有限公司,该公司为上海公共交通的信息化、自动化、现代化,打造国内首创。

PLC应用于喷泉控制系统的方案设计

采用PLC与计算机组成的喷泉控制系统,充分利用PLC的通信功能和编程特点,实现上位机与下位机之间的通信和控制,由远程计算机与PLC之间进行通信,通过PLC实现对喷泉各种水型和灯光的快速控制;另一方面,利用PLC的自诊断功能,可实现喷泉控制系统的故障诊断,不但缩短了维修时间,而且提高了控制系统的稳定性。

Bayesian network model for traffic flow estimation using prior link flows

In order to estimate traffic flow a Bayesian network BN model using prior link flows is proposed.This model sets link flows as parents of the origin-destination OD flows. Under normal distribution assumptions the model considers the level of total traffic flow the variability of link flows and the violation of the conservation law.Using prior link flows the prior distribution of all the variables is determined. By updating some observed link flows the posterior distribution is given.The variances of the posterior distribution normally decrease with the progressive update of the link flows. Based on the posterior distribution point estimations and the corresponding probability intervals are provided. To remove inconsistencies in OD matrices estimation and traffic assignment a combined BN and stochastic user equilibrium model is proposed in which the equilibrium solution is obtained through iterations.Results of the numerical example demonstrate the efficiency of the proposed BN model and the combined method.

An enhanced iterative joint channel estimation and symbol detection algorithm for OFDM systems

For orthogonal frequency division multiplexing (OFDM) wireless communication, the system throughput and data rate are usually limited by pilots, especially in a high mobility environment. In this paper, an enhanced iterative joint channel estimation and symbol detection algorithm is proposed to enhance the system throughput and data rate. With lower pilot power, the proposed scheme increases system throughput firstly, and then the channel estimation and symbol detection proceed iteratively within one OFDM symbol to improve the BER performance. In the proposed algorithm, the original channel estimate of each OFDM symbol is based on the channel estimate of the previous OFDM symbol, thus the variation of the mobile channel is traced efficiently, so the number of pilots in the time domain can be reduced greatly. Besides reducing the system overhead, the proposed algorithm is also shown by simulation to give much better BER performance than the conventional iterative algorithm does.

Accurate Interconnection Length and Routing Channel Width Estimates for FPGAs

We study the problem of the prediction of interconnection dimensions for FPGAs, including estimating interconnection length and channel width. Experimental results show that our estimates are more accurate than those of existing methods.

Effects of the profile of a supercavitating vehicle's front-end on supercavity generation

The authors designed three different front profiles for supercavitating vehicles based on cavity theory and the Granville streamlined equation are designed. Experiments were done using these front profiles in the Northwestern Polytechnical University high-speed water tunnel. The experiments indicated that the critical volume of gas required for supercavitation is affected by the axial distribution of the front-end＇s slope. The experimental data showed critical gas flow rates required for the three designs were less than rood-l, with the greatest decrease 24%. The experimental results also showed the supercavitation generation speeds of the models were faster than mod-1 by up to 32.4%. This verifies that the front profile of a supercaviting vehicle effects supercavity generation speed and critical gas flow rates. The smaller the changes in axial distribution of pressure, the higher the supercavity generation speed. The smaller the changes in curvature distribution of axial, the smaller the critical gas flow rates.

Modeling of Intelligent Integrated Network Management System Using Object Oriented Approach *

The concept of intelligent integrated network management (IINM) is briefly introduced. In order to analyze, design and implement IINM successfully, object oriented approach is testified to be an effective and efficient way. In this paper, object oriented technique is applied to the structural model of IINM system, The Domain object class and the MU object class are used to represent the manager and the managed resources. Especially, NM IA is introduced which is a special object class with intelligent behaviors to manage the resources efficiently.

Research and Implementation on HTTP Tunneling

The security problem of the Web system in the Internet based Intranet and the shortcomings of the methods used in solving this problem are analyzed and our system model of Web communication security are discussed, i.e, adding local proxy to browser and reverse proxy to Web server based on present Web browser and server. The transformation between HTTP message and secure HTTP message is implemented in these two proxy modules. The architecture and implementing method is given and the features of this module is also discussed.

INNOVATIVE PREDATORY SEARCH ALGORITHM FOR AIRCRAFT ARRIVAL SEQUENCING AND SCHEDULING PROBLEMS

To solve aircraft arrival sequencing and scheduling problems,and improve the typical predatory search algorithm（PSA）,an innovative PSA is developed.The new PSA uses variable constraints of local search and global search to avoid falling into local optimal solutions and the degeneration of solutions.To test the performance of new PSA,a case study with ten arriving flights and two runways is performed.Test results show that the new PSA performs much better than typical PSA and genetic algorithm（GA）in the aspects of the rate of gaining optimal solutions and the computational time.

Sea water temperature auto-monitoring system based on general packet radio service (GPRS)

This paper introduces the design and implementation of sea-water temperature auto-monitoring system based on General Packet Radio Service （GPRS）. This system integrates modern wireless communication technology, the signal gathering technology and computer network technology. MSC1210 microcontroller is used in data collection device in order to make system accurate and fast. In addition, wireless and Internet technologies are used for transferring and displaying collected field data. A prototype system has been completed and tested in field trials. The results proved the feasibility and usefulness of this system for monitoring the temperature. By using this system, a lot of resources and money can be saved.

Application of discrete choice model in trip mode structure forecast:a case study of Bengbu

In order to find the main factors that influence the urban traffic structure,a relational model between the travelers＇ characteristics and the trip mode choice is built.The data of urban residents＇ characteristics are obtained from statistical data,while the trip mode split data is collected through a trip survey in Bengbu.In addition,the discrete choice model is adopted to build the functional relationship between the mode choice and the travelers＇ personal characteristics,as well as family characteristics and trip characteristics.The model shows that the relationship between the mode split and the personal,as well as family and trip characteristics is stable and changes little as the time changes.Deduced by the discrete model,the mode split result is relatively accurate and can be feasibly used for trip mode structure forecasts.Furthermore,the proposed model can also contribute to find the key influencing factors on trip mode choice,and restructure or optimize the urban trip mode structure.

嵌入式软件测试平台配置

本文总结了建立软件评测中心必要条件,论述了软件测试过程并给出了各阶段的软件测试工具。在对市场充分调研的基础上,结合嵌入式软件的技术特点及具体工作需求,构建了一个嵌入式软件测试平台。

Direct computing methods for turn flows in traffic assignment

Two methods based on a slight modification of the regular traffic assignmentalgorithms are proposed to directly compute turn flows instead of estimating them from link flows orobtaining them by expanding the networks. The first one is designed on the path-turn incidencerelationship, and it is similar to the computational procedure of link flows. It applies to thetraffic assignment algorithms that can provide detailed path structures. The second utilizes thelink-turn incidence relationship and the conservation of flow on links, a law deriving from thisrelationship. It is actually an improved version of Dial's logit assignment algorithm. The proposedapproaches can avoid the shortcomings both of the estimation methods, e. g. Furness's model andFrator's model, and of the network-expanding method in precision, stability and computation scale.Finally, they are validated by numerical examples.

Research on service capacity of widened intersection based on traffic simulation

Delay analysis method is adopted to study the service capacity of a widened intersection. Traffic simulation software VISSIM is used for microscopic simulation of a widened intersection so as to obtain a delay curve. The delay-volume model of a widened intersection is established based on traffic simulation. The suggested value of basic service capacity of the widened left-turn lane is given along with how to determine correction factors and practical service capacity.

Calculation of thermodynamic properties in liquid phase for ternary Al-Ni-Zn alloys

The results of the calculation of thermodynamic properties in liquid state for ternary Al-Ni-Zn alloys using the newest version of the general solution model for thermodynamic prediction are presented. Nine sections with different molar ratios of Ni to Zn, Zn to Al and Al to Ni were investigated in a temperature interval of 1800-2000 K. Partial and integral molar thermodynamic properties in liquid phase for the Al-Ni-Zn ternary system are determined and discussed.

A DISTRIBUTED QOS ROUTING BASED ON ANT ALGORITHM FOR LEO SATELLITE NETWORK

Low Earth Orbit (LEO) satellites provide short round-trip delays and are becoming in- creasingly important. One of the challenges in LEO satellite networks is the development of specialized and efficient routing algorithms. To satisfy the QoS requirements of multimedia applications, satellite routing protocols should consider handovers and minimize their effect on the active connections. A distributed QoS routing scheme based on heuristic ant algorithm is proposed for satisfying delay bound and avoiding link congestion. Simulation results show that the call blocking probabilities of this al- gorithm are less than that of Shortest Path First (SPF) with different delay bound.

Coping with the Big Data:Convergence of Communications,Computing and Storage

To cope with the impact of big data,it is proposed to integrate the traditionally individual computing,communications and storage systems,which are getting inevitably converged.An effective information system capacity is introduced and discussed,aimed at excavating potentials of information system under a new paradigm with more degrees of freedom.

Equalization for continuous phase modulation over frequency-selective fading channels

This paper presents an equalization algorithm for continuous phase modulation （CPM） over frequency-selective channels. A specific training sequence is first embedded in each data packet. By recursive least-squares （RLS） estimation, the channel information parameters can be acquired, and a fractionally Simulation results show that the proposed algorithm can acquire the spaced equalizer performs joint decoding and equalization. channel information parameters rapidly and accurately, and that the fractionally spaced equalizer can eliminate the intersymbol interference （ISI） effectively, and is not sensitive to timing inaccuracy, so this algorithm can be exploited for demodulation system in burst mode.

Cellular automata modeling of pedestrian＇s crossing dynamics

Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian’s crossing dynamics. A conception of “stop point” is introduced to deal with traffic obstacles and resolve conflicts among pedestrians or between pedestrians and the other vehicles on the crosswalk. The model can be easily extended, is very efficient for simulation of pedestrian’s crossing dy- namics, can be integrated into traffic simulation software, and has been proved feasible by simulation experiments.

Application of GML and SVG in the development of WebGIS

Our study deals with two major issues impacting current WebGIS development： interoperability of heterogeneous data and visualization of vector data on the Web. By using the combination of Geography Markup Language （GML）, Scalable Vector Graphics （SVG） and Web Feature Service （WFS） Implementation Specifications developed by the OpenGIS Consortium （OGC）, a strategy of WebGIS is proposed. The GML is used as a coding and data transportation mechanism to realize interoperability, the SVG to display GML data on the Web and the WFS as a data query mechanism to access and retrieve data at the feature level in real time on the Web. A case study shows that the combination mentioned above has enormous potential to achieve interoperability while not requiring considerable changes to existing legacy data. Original data formats need not be changed and could still be retrieved using WFS and transformed into GML in real time. SVG can oroduce suoerior ouality vector maps on a Web browser.