供应链环境中路径编码方法研究

随着现代供应链应用的不断发展和完善,对流通物品进行路径追溯显得越来越重要,而实现路径追溯的关键是对路径中的结点进行有效编码,以保证提供高效查询及更新。本文主要对目前广泛使用的编码方法包括区间编码、前缀编码、素数编码及向量编码等的实现原理进行了讨论,并结合供应链特点分析了它们的优缺点。最后,指出了供应链环境中路径编码方法的未来研究方向。     

通用顺序即位素因子FFT算法

本文从一维到多维的下标变换出发,得到了一种通用顺序,即位素因子FFT算法。与现在的素因子FFT算法相比较,这种算法不仅节省了约一半内存,而且有更高的计算效率。此外,这种算法能很方便地将逆变换也包括在同一程序内。     

Ramsey数R(3,28)新下界的并行计算

寻找有效的参数集,构造素数阶循环图,用并行算法获得二色Ramsey数R（3,q）的新下界:R（3,28）≥164。     

A general technoeconomic and environmental procedure for assessment of small-scale cogeneration scheme installations: Application to a local industry operating in Thrace, Greece, using microturbines

The present paper describes a proposed general systematic procedure for small-scale combined heat and power (CHP) exploitation (where “small-scale CHP” refers to CHP installations with electric capacities up to 1 MW). The mentioned systematic procedure is implemented through a developed computer code and may be applied to any such small-scale project in order to assess its suitability based on technoeconomic and environmental considerations. A dynamic database based on small-scale CHP units (available in the world market) and their pertinent technical, economical and environmental features is created and, in conjunction with the developed program, is used for determination of a suitable CHP unit (or system) size and the selection of the associated proper prime mover type for any project of interest. Using well-known economic criteria, the economic analysis is performed, including the sensitivity analysis of the considered project based on the main key system parameters. In terms of the socioeconomic analysis, a carbon tax (CT) scenario is considered, and its effect on the economic behavior of the project is investigated. Last, with respect to environmental considerations, the program calculates, for any such project, the avoided main pollutants and the fuel savings when a CHP system is applied. As a case study, a small textile industry operating in the Eastern Macedonia-Thrace Region of Greece is considered, and its associated (electrical and thermal) data are used as input data to the proposed computer program. In this application, two microturbine units are selected and thoroughly evaluated, and the pertinent simulation results are presented and discussed accordingly.     

基于Vega Prime的虚拟现实车辆智能运动模拟

基于虚拟车辆坐标和车辆运动状态对比实现了车辆运动控制方法,通过研究车辆自由行驶、跟驰和变道实现了车辆的虚拟车辆相应的运动策略,利用Vega Prime相关碰撞检测机制,实现了车辆信号控制,并在Vega Prime平台上使用VC++编程实现了虚拟车辆的智能运动模拟,最后采用北京五道口区域交通流实际算例验证了模拟方法的有效性.研究结果表明:通过对Vega Prime进行二次开发,可以实现高沉浸感、高人机交互的虚拟车辆智能运动模拟,模拟仿真结果与交通实际情况相符.     

红蓝对抗系统原型的程序实现方法

针对目前视景仿真系统应用范围狭窄、应用模式单一、应用目的老套等问题,利用优秀视景仿真系统VegaPrime2.0开发平台,结合VC＋＋多线程技术,提出了一种红蓝对抗系统原型的实现方法。该方法综合了虚拟现实中的三维建模、碰撞检测、环境特效等关键技术以及VC＋＋平台提供的网络通信技术、多线程处理技术、系统函数回调方法等,使得视景仿真应用由单机版走向网络版,扩大了应用范围;由普通的场景漫游走向网络式交互,丰富了应用模式;由效果演示走向理论方法的验证,更新了应用目的。实验结果表明,该方法对红蓝对抗系统的实现具有实用价值。     

基于C语言的RSA算法高效实现

RSA算法是现代公钥密码体制事实上的标准,虽然它有被椭圆曲线密码算法（ECC）取代的局势,但是研究RSA加密算法还有一定的实际意义。深入讨论RSA算法的实现细节,对RSA的快速实现给出一种高效实用算法。     

Experimental and simulation studies on the performance of standing wave thermoacoustic prime mover for pulse tube refrigerator

The thermoacoustic prime mover (TAPM) has gained considerable attention as a pressure wave generator to drive pulse tube refrigerator (PTR) due to no moving parts, reasonable efficiency, use of environmental friendly working fluids etc. To drive PTCs, lower frequencies (f) with larger pressure amplitudes (ΔP) are essential, which are affected by geometric and operating parameters of TAPM as well as working fluids. For driving PTRs, a twin standing wave TAPM is built and studied by using different working fluids such as helium, argon, nitrogen and their binary mixtures. Simulation results of DeltaEc are compared with experimental data wherever possible. DeltaEc predicts slightly increased resonance frequencies, but gives larger ΔP and lower temperature difference ΔT across stack. High mass number working fluid leads to lower frequency with larger ΔP, but higher ΔT. Studies indicate that the binary gas mixture of right composition with lower ΔT can be arrived at to drive TAPM of given geometry.     

Thermal precipitation or gelling behaviour of dissolved methylcellulose (MC) derivatives—Behaviour in water and influence on the extrusion of ceramic pastes. Part 1: Fundamentals of MC-derivatives

Methylcelluloses dissolved in water show a temperature dependent gelling behaviour. The gel temperatures depend mainly on the degree of substitution with methyl groups. The behaviour of methylcellulose containing pastes is of high importance in various applications. The paper describes the influence of the degree of substitution on the thermal characteristics of methylcelluloses in water and in ceramic pastes. The gelation temperature of the methylcellulose in both systems is increasing with decreasing degree of substitution. This enables a broader temperature window in the ceramic extrusion process. Extrusion near the gelation temperature normally leads to many defects in the extrudate. However, close to the gelation temperature the extruded profiles show more defects with methylcelluloses having a higher degree of substitution. Methylcelluloses having a low degree of substitution also enable a paste extrusion above the gelation temperature (up to 90 °C). This is not possible with currently commercially available methylcelluloses.     

Investigation on the generation mechanisms of acoustic streaming in a thermoacoustic prime mover

High-amplitude acoustic waves in thermoacoustic devices are responsible for the generation of a secondary flow called acoustic streaming. Superimposed on the oscillating flow, this secondary flow is an important source of energy dissipation. To remove acoustic streaming would result in substantial improvements in the energy performance of thermoacoustic devices. Understanding the control parameters and mechanisms of streaming generation is essential for controlling acoustic streaming.In this paper, streaming sources are investigated in a pressurized thermoacoustic prime mover. The device was designed and built at the LIMSI (Laboratoire d’Informatique pour la Mécanique et les Sciences de l’Ingénieur) to investigate acoustic streaming. To calculate the theoretical velocity in the thermoacoustic device, the usual modelings were extended to take into account the cross section variation. Measurements of acoustic streaming velocity performed by Laser Doppler Velocimetry are compared to the theoretical results. Finally, the good agreements obtained led to the validation of the theory. The validated theory was then used to study the mechanisms of streaming generation in order to determine their influences in the thermoacoustic prime mover and therefore reducing the secondary flow. Thereafter, the investigation was extended to four channels with different widths and according to results of the literature, the proportion of outer streaming compared to inner streaming decreases when the channel width decrease. The investigation showed that the mechanisms of acoustic streaming generation differ for large and narrow channels.