基于PTR2000的步进电机无线控制系统

介绍了一种基于无线射频模块PTR2000构成的步进电机远距离无接触控制系统,实现了对步进电机的无线控制,为步进电机的应用提供了参考.     

CDMA系统中自动功率控制对系统容量的影响

CDMA系统的容量主要受限于系统内移动台的相互干扰,所以如果每个移动台的信号到达基站时都达到最小所需的信干比,系统容量将会达到最大值。在CDMA蜂窝系统中,为了解决远近效应的问题,同时避免对其他用户过大的干扰,必须采用严格的自动功率控制。功率控制的目的就是既维持高质量通信。又不对同一频率的其它用户产生不应有的多址干扰。功率控制的目的是控制每个用户的发射功率,而使得基站接收收到的每个用户的功率接近,从而克服远近效应。     

高校计划财务处信息发布系统的实现

该文讨论了高校计划财务处信息发布系统的结构形式,并给出了该系统的工作原理以及所采用关键技术的解决方法。     

基于WEB的教学改革研究项目管理系统设计与实现

本文针对莆田学院现在教改研究项目管理方式的不足,设计并实现了局域网内基于WEB的教学改革研究项目管理系统。     

基于JPEG2000的码率控制算法的研究

码率控制是JPEG2000编码的重要过程,其算法的优劣直接决定着整个编码效率的高低和压缩图像质量的好坏.针对JPEG2000标准建议的码率控制算法的计算复杂度高且占用存储空间大的问题,提出了对隔行扫描编码通道算法ACPI的一种改进算法,包括添加估计斜率值阶段、逆转扫描分辨率水平顺序,以及逆转同等级子带扫描的顺序.实验结果表明,该算法有效地减少了一JPEG2000的计算复杂度和存储量,提高了性能.     

Adaptive channel and power allocation of downlink multi-user MC-CDMA systems

The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very attractive multiple access technique for high-rate data transmission in the future wireless communication systems. This paper is focused on the joint channel and power allocation in the downlink transmission of multi-user MC-CDMA systems and considers the throughput maximization problem as a mixed integer optimization problem. For simple analysis, the problem is divided into two less complex sub-problems: power allocation and channel allocation, which can be solved by a suboptimal Adaptive Power Allocation (APA) algorithm and an optimal Adaptive Channel Allocation (ACA) algorithm, respectively. By combining APA and ACA algorithms, an adaptive channel and power allocation scheme is proposed. The numerical results show that the proposed APA algorithm is more suitable for MC-CDMA systems than the conventional equal power allocation algorithm, and the proposed channel and power allocation scheme can significantly improve the system throughput performance.     

Throughput analysis of STS-based CDMA system with variable spreading factor in non-frequency selective Rayleigh fading channel

The throughput enhancement of space-time spreading (STS)-based code division multiple access (CDMA) system is investigated in this paper. Variable spreading factor (VSF) is utilized to improve the data throughput of the system in non-frequency selective Rayleigh fading channel. In this contribution, an analytical approach is proposed to compute a new expression for the bit error rate (BER) performance of the STS-based CDMA system against pre-despreading signal-to-noise-ratio (SNR) for different values of spreading factor. The other contribution of the paper is deriving a new analytical expression for the throughput enhancement of the VSF STS-based CDMA system in non-frequency selective Rayleigh fading channel. Simulation and analytical results demonstrate that using VSF method in STS-based CDMA system improves the throughput of the system by keeping the BER performance at a target level.     

AutoCAD 2000 Visual LISP ActiveX编程技术

Ｖｉｓｕａｌ ＬＩＳＰ不但提供了完全可视化的代码编写、调试环境,而且还可以利用先进的ＡｃｔｉｖｅＸ和事件反应器技术,使其比传统的ＡｕｔｏＬＩＳＰ开发的软件更具智能化、运行更为迅速。对ＡｃｔｉｖｅＸ技术在Ｖｉｓｕａｌ ＬＩＳＰ编程中的应用方法作了详细地介绍并附以相应的应用实例。     

Windows 2000公钥体系结构

介绍了Ｗｉｎｄｏｗｓ２０００公钥体系结构及其在电子商务中应用。ＰＫＩ的标准在不断发展,成为电子商务应用的必需技术。Ｗｉｎｄｏｗｓ２０００的ＰＫＩ体系以其新特点,将成为电子商务的理想平台     

Evolutionary Computation in Structural Design

The paper provides the results of preliminary research on the application of evolutionary computation to integrated structural design in which a complex design support tool automatically conducts both conceptual and detailed design. In the paper, a brief overview of the state of the art in evolutionary computation and its applications to structural design is provided. Next, Inventor 2000 is described, a unique research and structural design tool developed by the authors at George Mason University that combines an evolutionary computation component with a system for wind forces analysis, and a system for the analysis, design and optimisation of steel structures. The paper also presents the results of four structural design experiments conducted with Inventor 2000. The objective of experiments was to investigate various forms of evolutionary computation as applied to structure design. Finally, the paper provides the initial research conclusions and recommendations for further research.