空气源热泵热水系统选型与热水需求适配问题研究

空气源热泵热水系统在工程实践中的应用越来越广泛,而要提升系统的热效率,系统选型需与热水需求有效适配.从两个视角入手,首先根据某地水温与气温的变化情况,采用多项式拟合得热泵产水量曲面,随后系统地分析了某医院1年的实际热水用水实测数据,并按以春分月、年平均、秋分月3种特定工况选型比较了空气源热泵产水量与热水用水量的匹配程度...     

基于概率推理的Ad-hoc网络路径选择算法

针对Ad-hoc网络在路径选择上主要选择最短路径所出现的问题,从复杂适应系统理论的角度出发,将基于概率推理的路径选择算法加入到AODV(Ad hoc on-demand distance-vector)路由协议中,通过对节点的适应度进行概率推理来选择路径,有效地解决了Ad-hoc网络的拥塞和负载分配问题,改善了网络性能。采用面向对象的建模技术在OMNET++软件平台上进行仿真,结果证明该方法降低了延迟时间,提高了网络QoS,为Ad-hoc网络路由协议的发展提供了一个新思路。     

AAL适配MPEG—2视频信号的效率

分析了用不同ＡＡＬ适配ＭＰＥＧ－２视频信号的效率，并给出了具体计算公式，比较了在实用情况下，采用不同ＡＡＬ的优劣。     

Operating rules of irrigation reservoir under climate change and its application for the Dongwushi Reservoir in China

Since agriculture development would be affected by climate change, the reservoir operation for agricultural irrigation should be adjusted. However, there are to date few literatures addressing how to design adaptive operating rules for an irrigation reservoir. This study aims to analyze the adaption of fixed operating rules and to derive adaptive operating rules under climate change. The deterministic optimization model is established with the solving method of two-dimensional dynamic programming (TDDP), and its optimal trajectory is supplied to derive reservoir operating rules at time intervals of crop growth periods. Then, two alternative operating rules, including fixed operating rules based on historical data and adaptive operating rules based on climate change data, are extracted using the fitting method with the multiple linear regression model. The alteration of reservoir inflow under climate change is calculated by the Budyko formula. A case study of the China’s Dongwushi Reservoir shows that: (1) fixed operating rules are unable to adapt climate change in the future scenario. Thus, adaptive operating rules should be established, (2) adaptive operating rules can reduce profits loss resulting from climate change, and improve field soil water storages, and (3) precipitation reduction by 7%/40a is the major cause for agricultural profits loss, whereas, the decrement of agricultural profits is less than that of precipitation, which indicates agricultural crops have the resilience to resist the adverse influence from precipitation decrease. These findings are helpful for adaptive operation of irrigation reservoirs under climate change.     

具有非线性突触联接和适应性的人工神经元电路模型

基于匹配神经细胞突触、胞体和轴突的电神经生理特性,本文提出了一种接近真实神经细胞输入-输出关系和强度-时间曲线的,且具有非线性突触联接和适应性的非线性压控电阻电路模型,并分析了它的一些基本特性。结果表明,该模型比现存的神经网络更接近真实神经计算原理。由这一模型组成的胜者为王(WTAWinner-Takes-All)网络能够比模拟网络更有效地检测出最大输出,并引入了强度竞争和时间竞争两个新概念。     

Analysis of Source Rate Adaption for ATM networks using a dynamic flow model

This paper focuses on using Source Rate Adaption (SRA) as a viable flow control scheme in Asynchronous Transfer Mode (ATM) networks. A modeling technique related to conducting performance evaluation studies using a dynamic flow model has been developed. SRA control strategies at node, domain or network levels have been proposed. Computer simulations verify the validity of the model and strategies.     

A MODEL OF NEURAL CIRCUIT WITH ADAPTION AND NONLINEAR CONNECTION

Based on physiological properties of synapse, soma and axon, this paper presents and analyses a model of neural circuit which can approximately simulate input-output relation, strength-duration curve, adaption and nonlinear connection of real neuron. The obtained results show that the model approximates to realistic principles of neural computation better than the available neural networks. The impulse-coded WTA(winner takes all) networks constructed with the above model find the winner more effectively than the analog WTA. Finally, the two important concepts: time competition and strength competition are introduced, which illustrate that the model has abilities to perform series and parallel information processing.     

Universal Access in the Information Society: Methods, Tools, and Interaction Technologies

Accessibility and high quality of interaction with products, applications, and services by anyone, anywhere, and at any time are fundamental requirements for universal access in the emerging Information Society. This paper discusses these requirements, and their relation to the concept of automated adaptation of user interfaces. An example application is presented, showing how adaptation can be used to accommodate the requirements of different user categories and contexts of use. This application is then used as a vehicle for discussing a new engineering paradigm appropriate for the development of adaptation-based user interfaces. Finally, the paper investigates issues concerning the interaction technologies required for universal access. Published online: 23 May 2001     

自适应多结构元形态学边缘检测方法

对自适应选取结构元权值以及如何有效去除混合噪声是多结构元形态学边缘检测中尚待解决的两个问题,在深入研究各种形态学边缘检测方法的基础上,提出了基于灰度距离逻辑函数和基于边缘方差两种自适应多结构元形态学边缘检测方法。首先对原始图像进行最优阈值分割二值化,其次从灰度距离和边缘方差两个角度分别实现结构元的自适应选取,最后选择形态算子进行边缘检测。方法具有更好的抗噪性和灵活性,能更加精确的体现原有图像的边缘方向信息。通过仿真实验,验证了方法的可行性和有效性。     

企业管理效益欠佳原因浅析

提高企业经济效益,是所有企业追求的最终目标。近年来虽取得了一定的成效,但经济效益低下仍然是困扰企业经济发展的重要问题。文章从管理系统,管理应变和管理内容三方面分析了企业管理效益欠佳的原因。