地铁站台空调系统非线性预测控制策略

地铁站台空调系统回路众多且具有强耦合和非线性特性,PID控制方法参数整定困难,无法兼顾乘客舒适性和能效最优,由于系统建模困难,非线性优化算法计算量大,智能控制方法难以实现工程应用.对此,提出一种地铁站台空调系统预测控制策略.首先,根据热湿负荷平衡和能量守恒定律建立地铁站台热动态特性预测模型;然后,将满足乘客舒适性并节省能耗作为系统优化目标,使用神经网络作为优化反馈控制器,将系统优化目标函数作为控制器优化性能指标,结合变分法和随机梯度下降法,对神经网络控制器的权值和阈值进行在线滚动优化,算法计算量小,占用存储空间适中.仿真实验结果表明,所提出的预测控制策略与传统PID控制方法相比,在满足乘客舒适性要求的前提下,系统响应时间可缩短约39.6%,末端风机能耗降低约73.39%.     

数据中心制冷系统非线性模型预测控制

数据中心制冷系统具有非线性、强耦合和大滞后特性,目前常用的PID方法无法实现系统整体能效提升,而现有非线性优化算法计算量大,不易工程实现.鉴于此,提出一种数据中心制冷系统模型预测控制策略,上层优化层设计预测控制器,其目标为在满足制冷要求的前提下降低系统能耗,优化层采用神经网络作为反馈控制器,将系统整体优化目标函数作为神经网络控制器优化性能指标,结合变分法与随机梯度下降法,通过滚动优化求取下层各回路被控变量最优设定值,算法占用存储区适中、计算量小;下层现场控制层通过实时控制使各回路被控变量跟踪最优设定值,可以在不破坏原有现场控制系统的情况下实现性能优化.构建Trnsys-Matlab联合仿真平台,针对系统夏季、过渡季和冬季的控制策略进行仿真实验.结果表明,所提出控制策略能够在满足数据中心安全运行的前提下,实现系统整体能效提升,且具有良好的鲁棒性.     

冰蓄冷空调负荷预测的预估校正模型

为减小冰蓄冷空调系统的运行费用,降低空调系统的能耗,更精准地预测空调冷负荷,提出一种利用小波神经网络实现冰蓄冷空调负荷预测的方法,通过直接启发式动态规划实时优化模型参数,建立冰蓄冷空调系统的预估校正模型,解决传统神经网络预测收敛慢,易陷入局部最优,精度相对低的缺点,保证整个系统的运行稳定性。实验结果表明,该方法在冰蓄冷空调负荷预测中具有较高的准确性和鲁棒性,具有良好的应用价值。     

制冷站双目标权重自适应非线性预测控制

针对传统制冷站控制系统易产生振荡, 且无法实现系统性能整体优化的问题, 本文提出一种制冷站非线性 预测控制策略, 优化目标函数设计为满足建筑冷量需求的同时, 尽可能提高系统整体能效. 为解决上述两个优化目 标之间的矛盾关系, 本文采用模糊逻辑设计了优化目标权重自适应模块, 实时求取权重因子最优解; 针对非线性系 统在线优化求解困难问题, 本文提出了基于神经网络的非线性滚动优化算法, 采用神经网络作为反馈优化控制器, 并将系统优化目标函数作为在线寻优性能指标, 结合Euler-Lagrange方法和随机梯度下降法对控制器权值和阈值进 行在线寻优, 算法计算量小, 占用存储空间适中, 便于采用低成本的现场控制器实现制冷站预测控制. 仿真实验结果 表明, 本文所提出的预测控制策略与PID控制相比, 在未加入优化目标函数权重自适应模块情况下, 系统平均能效 比提高约32.5%; 进行优化目标函数权重自适应寻优后, 系统平均能效提高约39.43%.     

三相脉宽调制整流器的约束预测控制

本文将基于并行神经网络优化的约束模型预测控制(MPC)应用于脉宽调制(PWM)整流器中,提高了电网的质量.在三相静止坐标系下,建立了三相PWM整流器的解耦数学模型,采用约束模型预测控制策略,突破了有限集和无约束条件下预测控制的局限性.为了提高单步优化的速度,采用神经网络优化算法求解模型预测控制的在线优化.在保证系统单位功率因数的前提下,当系统负载突然变化时,具有快速动态响应稳定输出直流电压的性能.采用FPGA控制器实现并行计算,减少了预测控制算法的计算时间.最后,通过仿真和实验结果得到,采用本文的控制策略,总谐波失真(THD)降低了2.5%,达到稳态的时间大约是PI控制算法的五分之一,为12 ms,验证了该方法的可行性和有效性.     

鲁棒模型预测控制在变风量空调系统中的应用

在变风量空调系统中二次泵压差控制可以有效地减少空调能耗,为克服二次泵模型的不确定性,提高二次泵变频调速控制的响应速度和精度,采用基于线性矩阵不等式的鲁棒预测控制策略。算法分为离线和在线两个部分,离线时首先用传统算法得出目标函数上界,以此为已知量重新优化得到一系列较大的渐近稳定的不变椭圆集。在线时,每个采样周期用三个相邻的椭圆集优化来对状态变量进行精确定位,并给出控制量。给出在线优化的理论证明。通过和传统算法的仿真比较,表明该算法的有效性。二次泵压差控制的实验表明该算法可得到较大的可行域,系统响应快,控制效果好。     

基于神经网络的时滞系统预测控制

为了克服工业滞后系统难以建立准确模型、控制误差大的问题,文章采用基于神经网络的预测控制方法,将神经网络大延迟系统的辨识与基于模型预测的神经网络控制策略相结合,可以用于对具有变化参数或不确定性延迟时并的非线性大延迟系统的控制.仿真结果表明该方法在不引起振荡的同时大大提高了系统的稳定性能.     

基于IPSO-Elman神经网络的建筑暖通空调系统能耗预测方法

在建筑暖通空调系统能耗预测中,在不同负荷比率的作用下预测偏差较高,可靠性需要进一步提高.为此,提出了基于IP-SO-Elman神经网络的建筑暖通空调系统能耗预测方法.从正在运行的暖通空调系统中,提取能耗数据,在获得完整的能耗数据后,根据能耗数据的动态变化特点,计算IPSO-Elman神经网络的惯性权重和学习因子,将能耗...     

自适应变系数粒子群—径向基神经网络模型在负荷预测中的应用

为了提高短期电力负荷预测精度,提出了一种自适应变系数粒子群-径向基函数神经网络混合优化算法(AVCPSO-RBF).实现了径向基神经网络参数优化.建立了基于该优化算法的短期负荷预测模型,利用贵州电网历史数据进行短期负荷预测.仿真表明,该方法的收敛速度和预测精度优于传统径向基神经网络方法和粒子群-RBF神经网络方法及基于混沌理论的神经网络模型,该优化算法克服了径向基神经网络和传统的粒子群优化方法的缺点,改善了径向基神经网络的泛化能力,提高了贵州电网短期负荷预测的精度,各日预测负荷的平均百分比误差可控制在1.7%以内.该算法可有效用于电力系统的短期负荷预测.     

具有可参数化不确定性系统的对偶自适应模型预测控制

控制系统中存在的不确定性为其性能优化带来诸多问题.自适应控制和鲁棒控制是针对系统存在的不确定性而采取的不同设计策略;前者没有充分考虑系统的未建模动态,而后者往往是针对不确定的最大界而设计,具有较强的保守性.本文试图将自适应控制和鲁棒控制的策略相结合,提出了一种在模型预测控制中利用未来不确定信息的对偶自适应模型预测控制策略.该策略将系统中由未建模动态引起的不确定性参数化表达,并为其设定边界约束,作为优化问题中新的约束,在优化控制目标的同时减小系统不确定性对控制的影响.仿真结果表明,本文提出的算法较传统自适应模型预测控制算法,对于系统存在的不确定性由于在迭代过程中采用参数化描述,得到了更好的系统性能,且具有更好的收敛性.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。