A Primal-dual Steepest-edge Method for Even-flow Harvest Scheduling Problems

The even-flow harvest scheduling problem arises when the forestry agency has evolved into a rigid non-declining even-flow policy. In this paper, we investigate model formulation and solution strategies for the even-flow harvest scheduling problem. A multiple-objective linear programming problem is formulated for even-flow harvest scheduling problems with multiple-site classes and multiple periods. The aim of this problem is to simultaneously maximize a desired harvest-volume per hectare for each period of planning horizon and the total economic return. A block diagonal constraint structure, with many sets of network sub-problems and a set of coupling constraints, is identified in this linear programming problem. A longest path method for each of network sub-problems and a primal-dual steepest-edge algorithm for the entire problem are developed. The developed algorithm has been coded in Borland C++ and implemented on a personal computer. An illustrative example is used to display the detailed procedure for the developed algorithm and a real-world case study is used to show the trade-off between desired even-flow harvest volume policy and total economic return. Results show the potential benefits of this approach.     

火烧油层技术在庙5块低渗透稠油油藏中的应用

方法在物理模拟的基础上，利用数值模拟及油藏工程方法，对影响火烧油层的技术参数进行了优选研究，并对影响火驱成败的油藏地质参数、注气参数进行了分析。目的寻找适合庙５块低渗透稠油油藏的开采方法。结果提出了庙５块火驱的最佳开采方式、点火参数及注气参数；庙５块火驱生产后，平均单井日产液由０１ｔ上升到５６ｔ，平均单井日产油由０１ｔ上升到３５ｔ，生产２６ｄ后由于压风机供风不足被迫停止火驱注气；从数模结果看：火驱最终采收率可达３９８％。结论火烧油层是一种潜力很大的稠油开采方法，但其物理、化学反应机理复杂，火烧前缘难以控制；庙５块火驱初期虽然见到了一定的生产效果，但没有取得经济效益     

Modeling video sources for real-time scheduling

What is the impact of the autocorrelation of variable-bit-rate (VBR) sources on real-time scheduling algorithms? Our results show that the impact of long term, or interframe, autocorrelation is negligible, while the impact of short term, or intraframe, autocorrelation can be significant. Such results are essentially independent of the video coding scheme employed. To derive these results, video sequences are modeled as a collection of stationary subsequences called scenes. Within a scene, a statistical model is derived for both the sequence of frames and of slices. The model captures the distribution and the autocorrelation function of real-time video data. In previous work, the pseudoperiodicity of the slice level auto-correlation function made it difficult to develop a simple yet accurate model. We present a generalization of previous methods that can easily capture this pseudoperiodicity and is suited for modeling a greater variety of autocorrelation functions. By simply tuning a few parameters, the model reproduces the statistic behavior of sources with different types and levels of correlation on both the frame and the slice level.     

Petri net based process scheduling: A model of the control system of flexible manufacturing systems

In this paper, we propose a class of algorithms for the sub-optimal solution of a particular class of problems of process scheduling, particularly focusing on a case study in the area of flexible manufacturing systems (FMSs). The general class of problems we face in our approach is characterized as follows: there is a set of concurrent processes, each formed by a number of temporally related tasks (segments). Tasks are executable by alternate resource sets, different both in performance and costs. Processes and tasks are characterized by release times, due dates, and deadlines. Time constraints are also present in the availability of each resource in resource sets. It has been proven that such a problem does not admit an algorithm for an optimal solution in polynomial time. Our proposed algorithm finds a sub-optimal schedule according to a set of optimization criteria, based on task and process times (earliness, tardiness), and/or time independent costs of resources. Our approach to process scheduling is based on Timed Coloured Petri Nets. We describe the structure of the coordination and scheduling algorithms, concentrating on (i) the general-purpose component, and (ii) the application-dependent component. In particular, the paper focuses on the following issues: (i) theautomatic synthesis of Petri net models of the coordination subsystem, starting from the problem knowledge base; (ii) the dynamic behavior of the coordination subsystem, whose kernel is a High Level Petri net executor, a coordination process based on an original, general purpose algorithm; (iii) the structure of the real-time scheduling subsystem, based on particular heuristic sub-optimal multi-criteria algorithms. Furthermore, the paper defines the interaction mechanisms between the coordination and scheduling subsystems. Our approach clearly distinguishes the mechanism of the net execution from the decision support system. Two conceptually distinct levels, which correspond to two different, interacting implementation modules in the prototype CASE tool, have been defined: theexecutor and thescheduler levels. One of the outstanding differences between these levels is that the executor is conceived as a fast, efficient coordination process, without special-purpose problem-solving capabilities in case of conflicts. The scheduler, on the other hand, is the adaptive, distributed component, whose behavior may heavily depend on the problem class. If the scheduler fails, the executor is, in any case, able to proceed with a general-purpose conflict resolution strategy. Experimental results on the real-time performance of the kernel of the implemented system are finally shown in the paper. The approach described in this paper is at the basis of a joint project with industrial partners for the development of a CASE tool for the simulation of blast furnaces.     

Vibration Monitoring and Diagnosis of Pipe-line Pumps on Offshore Platforms

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An efficient heuristic for scheduling batches of parts in a flexible flow system

Flexible manufacturing systems (FMSs) are a class of automated systems that can be used to improve productivity in batch manufacturing. Four stages of decision making have been defined for an FMS—the design, planning, scheduling, and control stages. This research focuses on the planning stage, and specifically in the area of scheduling batches of parts through the system.The literature to date on the FMS planning stage has mostly focused on the machine grouping, tool loading, and parttype selection problems. Our research carries the literature a step further by addressing the problem of scheduling batches of parts. Due to the use of serial-access material-handling systems in many FMSs, the batch-scheduling problem is modeled for a flexible flow system (FFS). This model explicitly accounts for setup times between batches that are dependent on their processing sequence.A heuristic procedure is developed for this batch-scheduling problem—the Maximum Savings (MS) heuristic. The MS heuristic is based upon the savings in time associated with a particular sequence and selecting the one with the maximum savings. It uses a two-phase method, with the savings being calculated in phase I, while a branch-and-bound procedure is employed to seek the best heuristic solution in phase II. Extensive computational results are provided for a wide variety of problems. The results show that the MS heuristic provides good-quality solutions.     

潜油螺杆泵采油系统设计与应用技术分析

潜油螺杆泵采油技术在某些方面具有其他人工举升技术不可比拟的优点，特别适合于我国渤海湾一带粘油区、海上平台的采油作业，但这项技术在我国实际开发应用的时间还比较短，人们对这项技术的了解还不够深入，很多单项技术还有待于更多的人去关注和研究.介绍了潜油螺杆泵采油系统的结构，总结了该项采油技术与其他常用采油技术相比较的特点，系统地阐述了国内外的发展状况，分析了以往投入生产试运行时系统失效的原因并提出了相应的解决办法，最后探讨了系统设计技术的发展趋势.     

通用雷达故障诊断专家系统的设计

目的：为了提高雷达装备故障诊断的效率和可靠性。方法：通过对雷达装备综合测试和故障诊断要求和方法的分析。介绍一种适用于雷达装备的故障智能诊断专家模型，探讨了该模型的基本结构和相应的推理机制及故障诊断策略。结果：结论雷达故障诊断的特点，研究了该模型及诊断方法在雷达装备中的具体应用，证实了该方法是有效的。结论：将自动测试技术和专家系统相结合，可以提高故障诊断的效率和可靠性。     

同杆并架双回线基于电流突变量的综合选相

相电流差突变量选相元件在单回线故障中具有良好的选相性能，但在同杆双回线跨线故障中可能误选相。利用六序故障分量的分析方法，分析了相电流突变量在同杆双回线跨线故障中的幅值和相位特征，给出了其相位比相方程。在此基础上，提出了一种运用测量阻抗和方向元件相结合的综合选相方法，并给出了选相流程图。仿真结果表明，在双回线简单故障和跨线故障时，基于单回线单端电气量的同杆并架双回线综合选相方法具有较理想的选相性能。     

改进的第三代相干算法及应用

在讨论相干技术发展及三代相干算法优缺点的基础上，介绍了改进的第三代相干算法。应用自行开发的相干软件对多个油气勘探和开发区块的三维地震资料进行处理、分析，对相干时窗长度、相关道数等参数对算法效果的影响及相干体对断层、异常地质体的识别，以及解释方法进行了探讨。应用实例证明，改进的第三代相干算法抗干扰能力强，横向分辨率高，不仅适用于倾斜地层，而且对断层尤其对小断层、异常地质体具有较高的检测能力，是油气勘探和开发的一项有效和实用的技术。