A tool to minimize the time costs of parallel computations through optimal processing power allocation

In this paper, we present a software system, OPAS (Optimal Allocation System), that incorporates the optimal allocation policy in the analysis of the time-cost behaviour of parallel computations. OPAS assumes that the underlying system which supports the executions of parallel computations has a finite number of processors, that all the processors have the same speed and that the communication is achieved through a shared memory. OPAS defines the time cost as a function of the input, the algorithm, the data structure, the processor speed, the number of processors and the processing power allocation. In analysing the time cost of a computation, OPAS first uses the optimal allocation policy that we developed previously to determine the amount of processing power each node receives and then derives the computation's time cost. OPAS can evaluate different time-cost behaviours, such as the minimum time cost, the maximum time cost, the average time cost and the time-cost variance. It can also determine the speed-up and efficiency, and plot the time-cost curve and time-cost distribution.     

Generalizations of the sethi-ullman algorithm for register allocation

The Sethi-Ullman algorithm for register allocation finds an optimal ordering of a computation tree. Two simple generalizations of the algorithm increase its applicability without significantly increasing its cost.     

Coordination Approaches and Systems – Part II: An Operational Perspective

This is the second of two papers surveying research in coordination approaches and systems. This paper is concerned with operational coordination, which is aimed at coordinating activities such that the design process can be performed in a near optimal manner with respect to time, and the allocation and utilisation of resources. Aspects of coordination categorised as operational include resource management, scheduling and planning. The first of these two papers presents a review of coordination from a strategic perspective, which is concerned with the decision management aspects of coordination. Greater emphasis is now being placed on the significance of organising the design process as this affects time to market, product quality, cost, and consequently product success. The aim of this paper is to present a fundamental review of operational coordination approaches and systems. The 1990s has seen much progress being made towards a greater understanding and appreciation of coordination in various disciplines through the development of a wide range of approaches and systems. However, there remains a requirement to formally identify the key issues involved in coordination such that a widely accepted representation can be agreed upon. Consequently, research should continue to be supported in the exploration for a unified approach to coordination which will permit a broader and greater understanding of those aspects involved.     

Required Work in the M/M/1 Queue,with Application in IP Packet Processing

We consider the ordinary M/M/1 queue with the FIFO queueing discipline. It seems that the sum of service times of the customers in the system (or the required work, as we call it briefly) is a random variable that is not considered before. In this paper we derive the equilibrium distribution of this variable. The task is not quite trivial because of the dependencies between the elapsed service time and the number of customers in the system. Our motivation for this problem comes from the performance analysis of a dynamic memory allocation scheme of a packet buffer.     

基于水权分配与交易的水管理机制研究 ——以新疆塔里木河流域为例

结合新疆塔里木河流域的实际情况，首先从对策论的角度对水资源在上、中、下游地区分配使用的冲突进行了剖析，认为计划经济体制下行政命令式的水管理概念和模式越来越难以适应稀缺程度不断加剧的水资源分配和利用形势。现行水管理机制缺乏相应的利益调节和经济激励手段。作者从水资源产权界定、分配和交易的角度对塔里木河流域水管理机制创新进行了分析和探讨。基于水权分配和交易的流域水管理机制模式为其它流域水资源分配利用和全国水资源实现可持续发展和管理提供了有益的思路。     

A Resource Allocation Approach for the Generation of Service-Dependent Demand Matrices for Communications Networks

Estimating point-to-point demands from partially available information, such as total demand volumes originating and terminating at nodes and traffic volumes routed on links, has significant applications in various areas, such as communications network planning and transportation planning. Existing methods include matrix and link scaling methods, statistical methods, more complex mathematical programming models, and forecasting using demographic data. We present a new mathematical programming model based on equitable resource allocation. The model considers multiple services, e.g., data, video, and voice, and generates a point-to-point demand matrix for each service. Originating and terminating demands for each service and link loads, aggregated over all services, are viewed as resources. Each point-to-point demand is associated with a performance function that measures its weighted, normalized deviation from a target defined by a service-dependent community of interest matrix. The model formulation has a lexicographic minimax objective function and multiple knapsack resource constraints. The model has an intuitively appealing interpretation and a specialized algorithm can generate demand matrices for large network problems very fast.     

电力市场定价机制对不同类型机组配置结构的影响

电力市场中的定价机制主要包括电力交易所一部制电价和电力库两部制电价2种。定价机制不仅对总装机容量产生影响，也会使机组的类型配置偏离社会最佳组合，最终导致总发电成本的上升。在完全竞争的电力市场中，研究了2种定价机制对不同类型发电机组配置结构的影响，发现电力库模式中的容量费用会导致峰荷机组的过度投资，而附加费用和高峰需求的不确定性会导致基荷机组的过度投资。     

Risk-based rules for crane safety systems

The International Maritime Organisation (IMO) has recommended a method called formal safety assessment (FSA) for future development of rules and regulations. The FSA method has been applied in a pilot research project for development of risk-based rules and functional requirements for systems and components for offshore crane systems. This paper reports some developments in the project. A method for estimating target reliability for the risk-control options (safety functions) by means of the cost/benefit decision criterion has been developed in the project and is presented in this paper. Finally, a structure for risk-based rules is proposed and presented.     

Can Economics-based Resource Allocation Prove Effective in a Computation Marketplace?

Several companies offer computation on demand for a fee. More companies are expected to enter this business over the next decade, leading to a marketplace for computation resources. Resources will be allocated through economic mechanisms that establish the relative values of providers and customers. Society at large should benefit from discoveries obtained through the vast computing power that will become available. Given such a computation marketplace, can economics-based resource allocation provide benefits for providers, customers and society? To investigate this question, we simulate a Grid economy where individual providers and customers pursue their own ends and we measure resulting effects on system welfare. In our experiments, customers attempt to maximize their individual utilities, while providers pursue strategies chosen from three classes: information-free, utilization-based and economics-based. We find that, during periods of excess demand, economics-based strategies yield overall resource allocation that benefits system welfare. Further, economics-based strategies respond well to sudden overloads caused by temporary provider failures. During periods of moderate demand, we find that economics-based strategies provide ample system welfare, comparable with that of utilization-based strategies. We also identify and discuss key factors that arise when using economic mechanisms to allocate resources in a computation marketplace.     

涉及生态环境需水的水资源合理配置

对涉及生态环境需水的水资源合理配置问题进行了探讨，提出了面向生态的水资源合理配置问题、基于降水资源的合理配置问题、针对不同地区不同条件的配置方法问题及河流水资源配置的40％原则，并对相关问题进行了进一步的探讨，有助于对水资源合理配置理论的进一步认识。