On-line Cache Resizing for Low-Power Microprocessors

We propose a novel scheme, called on-line cache resizing (OCR), to dynamically resize the cache and meet the size requirement of each application. At each periodic interval, the scheme gathers the cache hit-miss statistics at runtime using an extra tag array. These executing statistics serve as inputs to an analytical model of cache energy. The scheme uses energy as a primary metric to dynamically increase/decrease the number of active cache ways for the next interval. The scheme minimizes the active cache size to save energy with minimal performance loss. The simulation with SPEC 2000 benchmarks shows that OCR results in an average of 38.4% energy saving compared with fixed-size caches, with only 2.0% performance loss.     

一种实用的配电网潮流算法

目前matlab潮流计算程序多是基于输电网开发,而对配电网中潮流计算程序较少开发。配电网由于其特有的辐射性、R／X较大、节点较多的特性,导致用于输电网的潮流计算方法由于收敛性问题并不适用于配电网系统中。针对辐射性配电网的特点,开发了用于配电网潮流计算的matlab程序,该程序采用新的支路选择方法,无需对网络进行复杂的编号,并通过算例验证了程序的正确性。     

Cost-benefit of interface management improvement in design-manufacturing chain

Design-manufacturing chain (D-MC) is the most important link of the supply chain with the greatest possibility in cost reduction. How to strengthen the effective management of interfacial relationship between designer and manufacturer and increase the efficency of interface management concerns the efficiency of the whole supply chain. In order to evaluate and improve the impacts of D-MC interfacial relationship, first we should construct the evaluation index system and then we should analyze the total cost and benefit of the interfacial relationship betterment, including the cost of member units in D-MC, the opportunity cost of cooperation partners, and the market returns resulted from the interfacial relationship improvement, which will advance the whole supply chain efficiency as well as enhance the management performance of D-MC. Foundation item: the Chinese Public Service Platform for Science and Technology Management (No. 06DZ22924) and the Economic Globalization and Innovation (No. 08692106700)     

A simulation study of service differentiation for the bandwidth request scheme in fixed IEEE 802.16 network

Various flexible mechanisms related to quality of service (QoS) provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the IEEE 802.16 standards. Among the mechanisms, contention based bandwidth request scheme can be used to indicate bandwidth demands to the base station for the non-real-time polling and best-effort services. These two services are used for most applications with unknown traffic characteristics. Due to the diverse QoS requirements of those applications, service differentiation (SD) is anticipated over the contention based bandwidth request scheme. In this paper we investigate the SD with the bandwidth request scheme by means of assigning different channel access parameters and bandwidth allocation priorities at different packets arrival probability. The effectiveness of the differentiation schemes is evaluated by simulations. It is observed that the initial backoff window can be efficient in SD, and if combined with the bandwidth allocation priority, the SD performances will be better. Foundation item: the National Basic Research Program (973) of China (No. 2005C13321804)     

Site Earthquake Characteristics and Dynamic Parameter Test of Phase Ⅲ Qinshan Nuclear Power Engineering

The earthquake characteristics and geological structure of the site to sitting the Qinshan Nuclear Power Station are closely related. According to site investigation drilling, sampling, seismic sound logging wave test in single-hole and cross-hole, laboratory wave velocity test of intact rock, together with analysis of the site geological conditions, the seismic wave test results of the site between strata lithology and the geologic structure were studied. The relationships of seismic waves with the site lithology and the geologic structure were set up.The dynamic parameters of different grades of weathering profile were deduced. The results assist the seismic design of Phase Ⅲ Qinshan Nuclear Power Plant, China.     

In-home power line communication media access control protocol based on collision resolution

Most existing media access control (MAC) protocols in power line communication (PLC) networks just discard the colliding data packets when collision occurs. The collision deteriorates throughput and delay performance of system under high traffic conditions. This article presents a novel media access scheme with fast collision resolution for in-home power line networks. It works by first recognizing the colliding stations through detecting the inserted unique ID sequence ahead of data packets, then the source nodes retransmitting their packets immediately after the collision slot. The proposed protocol maintains the benefits of ALOHA systems. It needs no scheduling overhead and is suitable for bursty sources, such as multimedia data packets. Computer simulations have demonstrated that this approach can achieve high throughput due to its ability of resolving collisions.     

基于PCI-7464采集卡的多通道压电陶瓷驱动电源的研制

利用PCI-7464数据采集卡提供的DLL动态连接库函数及VB中的Timer控件,实现了8路0～10 V的压电陶瓷驱动电源模拟控制信号的可编程输出,通过后续的放大电路,实现了0～300 V控制电压的输出.所设计电源具有低纹波、多通道、高精度等特点,满足压电陶瓷的驱动要求.     

基于电子商务的中小企业发展策略

随着计算机与网络技术的普及与发展,电子商务迅速崛起,众多的信息技术企业、风险投资公司、生产流通企业纷纷开展电子商务。根据近几年中小企业电子商务发展现状,分析中小企业在发展电子商务过程中存在的主要特征,并提出广大中小企业应充分利用电子商务平台提供增值服务,进行业务的深度整合,理性思考自身的电子商务发展策略。     

三维地形可视化技术在铁路电力设计中的应用

三维地形可视化技术一直是地理信息系统、数字摄影测量、虚拟现实等领域的研究热点.铁路电力线路设计过程中,通过三维地形可视化技术,可以使设计人员对地形有较直观的认识,提高贯通线路设计的效率和质量.根据数字高程模型(DEM)数据,利用VC++6.0和OpenGL作为平台,重点讨论建立地形三维可视化系统的关键技术和实现过程.     

基于贯通线阻抗距离保护的配电自动化开关研究

讨论以单片机为控制核心的自动阻抗式配电自动化开关系统,目的是验证和进一步提高继电器的自动化性能.论述阻抗距离保护的基本原理,分析阻抗式自动化开关控制器的构成和基本功能,提出阻抗式自动化保护开关在实际应用中的模型,并实际仿真模型故障后的电压电流变化,从而验证了原理算法的正确性.进而能够较好地解决贯通线自动化改造的现实问题.