有"石"之用--湖南大学法学院·建筑系馆群体设计

本文介绍了在湖南大学法学院、建筑系馆群体设计中,针对二者功能和空间上的不同需要,设计者从群体建筑的构成原则出发,重在体现法学院的内在逻辑性和建筑系馆空间的流动性;同时使用湘江砂石,运用水刷石工艺,对现代建筑设计中如何结合地域性进行了有益地探索.     

形式的逻辑──从提契诺学派看欧洲现代建筑

瑞士的提契诺学派以他们精练而娴熟的逻辑语言成为现代建筑的基本原理与地方文化结合的典范。以此为对象，尝试利用计算机技术对现代建筑作了本质性而非符号性的研究和分析。     

基于AMESim的泵车水泵液压系统流量匹配装置设计与研究

清洗水泵是泵车上必不可少的装备,水泵实际须配的功率很低(约3 k W),而泵车发动机功率很大(287 k W),现所有泵车水泵的液压系统,均采用定量泵-定量马达系统,在发动机高速运转、定量齿轮泵系统流量很大时,水泵将泵出高压水,而发动机怠速、系统流量低时,系统基本没法正常泵水工作。针对此问题,提出了一种定量泵-定量马达系统流量匹配的设计方法,该方法能保证水泵系统在泵车发动机从怠速到全速各工况下,均能正常工作、泵出高压水,并且利用AMESim软件,建立流量匹配装置的仿真模型,对流量匹配装置工作的动态特性进行仿真分析。仿真结果表明,该系统的动态工作性能完全满足设计的要求。     

Power Equalization Techniques for Three-Phase VSI-Driven Single-Phase Ozone Generators

The purpose of this article is to present a method to equalize power imbalances in single-phase loads driven by three-phase voltage source inverters. The objective is to unbalance the line-to-line voltages in order to equalize the individual load power. The method is evaluated under non-linear loads, considering the dispersion of the high-voltage transformer electrical parameters values usually found in ozone generating systems. Two methods are considered for equalizing the load power. In the progressive method, the power equalization is performed by a microcontroller and works setting up the voltage applied over each load in response to power feedback from the other loads. In addition, Fuzzy Logic concepts are also applied, permitting a fast response, in spite of lower precision in the power balancing. Analytical, simulation and experimental results validate both methods.     

Exploring stop-go decision zones at rural high-speed intersections with flashing green signal and insufficient yellow time in China

The objective of this study is to empirically analyze and model the stop-go decision behavior of drivers at rural high-speed intersections in China, where a flashing green signal of 3 s followed by a yellow signal of 3 s is commonly applied to end a green phase. 1, 186 high-resolution vehicle trajectories were collected at four typical high-speed intersection approaches in Shanghai and used for the identification of actual stop-go decision zones and the modeling of stop-go decision behavior. Results indicate that the presence of flashing green significantly changed the theoretical decision zones based on the conventional Dilemma Zone theory. The actual stop-go decision zones at the study intersections were thus formulated and identified based on the empirical data. Binary Logistic model and Fuzzy Logic model were then developed to further explore the impacts of flashing green on the stop-go behavior of drivers. It was found that the Fuzzy Logic model could produce comparably good estimation results as compared to the traditional Binary Logistic models. The findings of this study could contribute the development of effective dilemma zone protection strategies, the improvement of stop-go decision model embedded in the microscopic traffic simulation software and the proper design of signal change and clearance intervals at high-speed intersections in China.     

Synthesis of Dual Mode Logic

In recent years, the major focus of VLSI design has shifted from high-speed to low-power consumption. While standard CMOS-based digital design provides substantial flexibility during pre-silicon design phases, the characteristics of the gates are set by fabrication variations and environmental conditions and cannot easily be changed at runtime. The recently proposed Dual Mode Logic (DML) family provides a novel approach to provide this capability by introducing two configurable operating modes, static and dynamic, that enable fine-grained control of the power-performance tradeoff of a logic path. However, the introduction of a new topology requires the development of both a design methodology and techniques for integration in a robust design automation flow. Standard synthesis tools do not support dynamic gates, and in particular, dual-characteristic gates. Therefore, until now, DML has been limited to small, custom-made blocks and components. In this paper, we present a novel approach for the integration of DML into standard electronic design automation tools, as part of the standard digital design flow. The development of this approach and the accompanying design methodology enables DML to be used in larger designs, such as state-of-the-art, high-speed and/or low-power SoCs. We demonstrate the employment of the proposed approach in order to benefit from DML properties, and reduce the power consumption, while simultaneously improving the operating frequency of a number of test designs.     

Case-based reasoning assisted explanation of genetic algorithm results

Abstract

This paper describes a system for explaining solutions generated by genetic algorithms (GAs) using tools developed for case-based reasoning (CBR). In addition, this work empirically supports the building block hypothesis (BBH) which states that genetic algorithms work by combining good sub-solutions called building blocks into complete solutions. Since the space of possible building blocks and their combinations is extremely large, solutions found by GAs are often opaque and cannot be easily explained. Ironically, much of the knowledge required to explain such solutions is implicit in the processing done by the GA. Our system extracts and processes historical information from the GA by using knowledge acquisition and analysis tools developed for case-based reasoning. If properly analysed, the resulting knowledge base can be used: to shed light on the nature of the search space; to explain how a solution evolved; to discover its building blocks; and to justify why it works. Such knowledge about the search space can be used to tune the GA in various ways. As well as being a useful explanatory tool for GA researchers, our system serves as an empirical test of the building block hypothesis. The fact that it works so well lends credence to the theory that GAs work by exploiting common genetic building blocks.     

Nanoelectronic content-addressable memory

A novel nanoelectronic single-electron content addressable memory is designed and simulated. The proposed memory has three important building blocks: a storage block, a comparison block and an addressing block. These building blocks were built based on single-electron circuits such as Reset-Set latches, exclusive-or gates and a WTA neural network. Each one of the building blocks was separately adjusted to provide room temperature operation before being connected together. Some analyses concerning stability of each block and of the whole memory circuit were made. The nanoelectronic memory was successfully validated by simulation.     

首钢长钢H型钢堆垛床自动控制系统介绍

介绍了基于PLC自动化型钢堆垛控制系统的组成、网络配置、工艺流程以及人机界面;着重讨论吊车和堆垛台架的位置检测、定位,变频器的应用以及堆垛吊车磁铁的自动给磁与失磁控制。利用变频器替代电磁技术,结构简单,稳定高效。     

基于CANopen现场总线的在线制绒清洗机控制系统

根据在线制绒清洗机的工艺要求及特点,对采用了M258及CANopen现场总线控制系统的构成及网络控制结构进行了详细的研究,并结合底层的执行器及传感器实现了包括硅片的同步传输等主要控制功能。