基于Linux平台DCS操作站的实现

介绍在INFI-90系统中用Linux实现DCS操作站的方法、原理及实施过程。     

INFI-90 SOE系统的网络与通讯

结合洛阳首阳山电厂#1机DCS改造及调试运行情况，从硬件和软件两个方面介绍了INFI-90SOE系统的组成。从整个INFI-90通信系统入手剖析了SOE系统的通信情况，分析了SOE报表顺序混乱的原因并给出了解决方案，从常用的方法出发提出了解决SOE时钟同步问题的新思路。     

INFI-90分散控制系统中实时数据读写方法的研究与实现

INFI-90分散控制系统在国内使用较普遍。文中对INFI-90分散控制系统的实时数据处理的应用加以介绍，说明了使用应用程序接口(semAPI)开发数据读写的优点，并给出了利用semAPI实现实时数据的读写的程序。     

INFI-90分散控制系统与PI数据库的数据通讯技术

介绍了INFI-90分散控制系统系统与PI（Plant Information）数据库之间的数据通讯技术，详细阐述了接口的工作原理和PI数据库中标签点的相应属性的设置，从而为统一数据平台的建立提供了有力的支持。     

提高BAILEY INFI—90系统的安全可靠性

文章简要介绍了BAILEY INFI-90的系统结构,论述了控制系统在安全可靠性方面存在的问题,并提出了可行的解决方案。     

湛江发电厂首台300MW汽轮机组高压纯电调改造

主要介绍了双工质电液并存DEH系统在湛江发电厂300MW机组运行中存在的主要问题。经调研、可行性分析，及改造方案比较论证，电厂决定采用与INFI-90的DCS同型设备，对汽轮机控制系统进行高压纯电调系统改造，这样既节约了投资，又能与单元机组的DCS共享资源，取得了较好的效果。     

INFI-90开放通信网络系统的研究

通过对INFI-90开放通信系统的研究，较详细地阐述了该系统的通信网络结构、通信协议、信息格式、关键技术和开放接口等方面的内容。     

采用INFI—90的控制系统仿真装置

INFI-90是美国Bailay公司在N-90基础上推出的第三代分散型控制系统,也是集计算机技术、控制技术、通信技术和CRT显示技术于一体的新型过程控制装置.由于INFI-90的设备来源主要靠国外进口,许多从事自动控制的人员对它还比较陌生,在分散型控制系统的设计、安装、调试和运行维护方面还都缺乏经验,特别是大型大电机组的自动控制系统,受机组安全运行的限制,一般很难在现场对系统进行有效的试验研究.因此,很有必要建立一套采用INFI-90的控制系统仿真装置.     

韶关发电厂10#机组DCS调试期间出现的问题及改进措施

韶关电厂10#机组及其DCS介绍;INFI-90DCS在机组调试期间暴露的主要缺陷、故障及原因分析、采取的处理或改进措施.     

基于曲线重合度比较的预估Smith控制器参数整定方法

通过对INFI-90集散型控制系统中预估Smith控制器结构原理的分析，提出了该控制的一种工感动曲线重合度比较的参数整定方法。具体介绍整定原理、逻辑组态修改和实际整定要点。还列出了该参数整定方法的特点。     

A linear algorithm for the pos/neg-weighted 1-median problem on a cactus

The 1-median problem on a network asks for a vertex minimizing the sum of the weighted shortest path distances from itself to all other vertices, each associated with a certain positive weight. We allow fornegative weights as well and devise an exact algorithm for the resulting ‘pos/neg-weighted’ problem defined on a cactus. The algorithm visits every vertex just once and runs thus in linear time. This research has been supported by the Spezialforschungsbereich F 003 ‘Optimierung und Kontrolle’, Projektbereich Diskrete Optimierung.     

Maintenance routing for train units: The interchange model

Train units need regular preventive maintenance. Given the train units that require maintenance in the forthcoming 1–3 days, the rolling stock schedule must be adjusted so that these urgent units reach the maintenance facility in time. In this paper, we present an integer programming model for solving this problem, give complexity results, suggest solution methods, and report our computational results based on practical instances of NS Reizigers, the main Dutch operator of passenger trains.     

Semi-online Machine Covering on Two Uniform Machines with Known Total Size

This paper investigates semi-online scheduling problem with known total size on two uniform machines for maximizing the minimum machine completion time. Lower bounds and optimal algorithms for every s≥1 are given, where s is the speed ratio of two machines. Both the overall competitive ratio and the competitive ratio for are strictly smaller than those of the optimal algorithms of the corresponding semi-online scheduling problem with known optimal value. It indicates that two related semi-online problems are different.     

Preemptive and Non-preemptive On-line Algorithms for Scheduling with Rejection on Two Uniform Machines

In this paper, we consider the problem of on-line scheduling a job sequence on two uniform machines. A job can be either rejected, in which case we pay its penalty, or scheduled on machines, in which case it contributes its processing time to the makspan of the constructed schedule. The objective is to minimize the sum of the makespan of the schedule for all accepted jobs and the penalties of all rejected jobs. Both preemptive and non-preemptive versions are considered. For the preemptive version, we present an optimal on-line algorithm with a competitive ratio for any s≥1, where s is the machine speed ratio. For the non-preemptive version, we present an improved lower bound. Moreover, as an optimal algorithm for s≥1.6180 is known, we present a modified version of the known algorithm, and show that it becomes optimal for any 1.3852≤s<1.6180 and has a smaller competitive ratio than that of original version for any 1≤s<1.3852. The maximum gap between its competitive ratio and the lower bound is 0.0534.     

On Hoffman's celebrated cycling LP example

We answer two questions that naturally arise while dealing with Hoffman's celebrated 50-year-old linear program to be solved by the primal simplex method, where an angle θ$\theta$ and a scaling factor ω$\omega$ are adjustable parameters. In particular, we determine what conditions have to be imposed on ω$\omega$ for classical cycling to occur with θ=2π/5$\theta =2\pi /5$, and what on θ$\theta$ with ω=±tan(θ)$\omega =\pm \tan (\theta )$. The first answer reveals that the sufficient condition widely spread over the literature is false, so fixing it turns this example into a correct example of classical cycling. Some progress towards necessary and sufficient conditions for cycling to occur in this example is also reported.     

A note on MULTIFIT scheduling for uniform machines

In this note, we derive the tight worst case bound √6/2+(1/2) ^k for scheduling with the MULTIFIT heuristic on two parallel uniform machines withk calls of FFD within MULTIFIT. When MULTIFIT is combined with LPT as an incumbent algorithm the worst case bound decreases to √2+1/2+(1/2) ^k . Partially supported by SFB F003 “Optimierung und Kontrolle”, Projektbereich Diskrete Optimierung and by the National Natural Science Foundation of China, Grant 19701028.     

Spectral projected subgradient with a momentum term for the Lagrangean dual approach

The Lagrangean dual problem, with a non-differentiable convex objective function, is usually solved by using the subgradient method, whose convergence is guaranteed if the optimal value of the dual objective function is known. In practice, this optimal value is approximated by a previously computed bound. In this work, we combine the subgradient method with a different choice of steplength, based on the recently developed spectral projected gradient method, that does not require either exact or approximated estimates of the optimal value. We also add a momentum term to the subgradient direction that accelerates the convergence process towards global solutions. To illustrate the behavior of our new algorithm we solve Lagrangean dual problems associated with integer programming problems. In particular, we present and discuss encouraging numerical results for set covering problems and generalized assignment problems.     

Parameterized on-line open-end bin packing

This note deals with a new variant of bin packing, the so-called open-end bin packing problem in which a bin can be filled to a level exceeding its capacity by its last item if it is not full immediately before the last is packed. We investigate the on-line version of this problem and give best possible algorithms for parametric cases. This work is supported by the Foundation under State Education Committee of China.     

Advertising channel selection in a segmented market

We consider a market with a finite number of segments and assume that several advertising channels are available, with different diffusion spectra and efficiencies. The problem of the choice of an advertising channel to direct the pre-launch campaign for a new product is analyzed in two steps. First, an optimal control problem is solved explicitly in order to determine the optimal advertising policy for each channel. Then a maximum profit channel is chosen. In a simulation example we consider the choice of a newspaper among six available and analyze the relations among the firm target market and the advertising channels environment which induce the optimal decision.     

A Boundary Point Method to Solve Semidefinite Programs

We investigate the augmented Lagrangian penalty function approach to solve semidefinite programs. It turns out that this method generates iterates which lie on the boundary of the cone of semidefinite matrices which are driven to the affine subspace described by the linear equations defining the semidefinite program. We provide some computational experience with this method and show in particular, that it allows to compute the theta number of a graph to reasonably high accuracy for instances which are beyond reach by other methods. Supported in part by EU project Algorithmic Discrete Optimization (ADONET), MRTN-CT-2003-504438.