应用批处理实现学校机房高效管理

批处理命令简洁而高效,在许多不便安装硬件还原卡的学校机房,系统维护工作比较繁琐,应用批处理命令实现了开机自动系统优化,以及网络克隆后自动修改机器配置,为学校机房管理提供了一条比较实用方便的维护管理方法。     

Scheduling a batching machine with convex resource consumption functions

In various industries jobs undergo a batching, or burn in, process where different tasks are grouped into batches and processed simultaneously. The processing time of each batch is equal to the longest processing time among all jobs contained in the batch. All to date studies dealing with batching machines have considered fixed job processing times. However, in many real life applications job processing times are controllable through the allocation of a limited resource. The most common and realistic model assumes that there exists a non-linear and convex relationship between the amount of resource allocated to a job and its processing time. The scheduler?s task when dealing with controllable processing times is twofold. In addition to solving the sequencing problem, one must establish an optimal resource allocation policy. We combine these two widespread models on a single machine setting, showing that both the makespan and total completion time criteria can be solved in polynomial time. We then show that our proposed approach can be applied to general bi-criteria objective comprising of the makespan and the total completion time.     

Single machine batch scheduling problem with family setup times and release dates to minimize makespan

In this paper we consider the single machine batch scheduling problem with family setup times and release dates to minimize makespan. We show that this problem is strongly NP-hard, and give an time dynamic programming algorithm and an time dynamic programming algorithm for the problem, where n is the number of jobs, m is the number of families, k is the number of distinct release dates and P is the sum of the setup times of all the families and the processing times of all the jobs. We further give a heuristic with a performance ratio 2. We also give a polynomial-time approximation scheme (PTAS) for the problem.     

冷热原油顺序输送温度场波动规律

为了更加准确地确定冷热原油顺序输送温度场波动规律,对管道周围土壤温度场绝热面漂移进行了研究。针对冷热原油顺序输送过程中埋地管道周围土壤温度场变化特征,建立了土壤温度场非稳态传热模型,利用CFD软件,对冷热原油顺序输送过程中不同循环周期不同时刻的土壤温度场进行了数值模拟及分析。结果表明,土壤温度场绝热面的漂移具有一定的规律,绝热面随冷热原油顺序输送时间呈周期性漂移,漂移周期与冷热油顺序输送的循环周期相同;土壤温度场绝热面的漂移周期及距离与冷热油顺序输送的循环周期有关。     

烧结生产自动配料控制系统

介绍了烧结生产自动配料控制系统的组成及工作原理.控制系统采用上下两级的计算机控制形式,并在系统的设计中,根据生产的实际情况采用了新的控制思想和控制方法.     

A hybrid tabu search for batching and sequencing decisions in a single machine environment

This paper proposes a hybrid tabu search (HTS) to minimise the total weighted tardiness (TWT) for the batching and sequencing of jobs originating from incompatible families in which sequence dependent family setup times exist on single machine. The developed HTS includes distinguished features such as the strict arc based tabu classification along with dynamic tabu tenures, hybrid neighbourhood structures and iterative phases which consist of job and batch sequencing phases. The authors developed a testing methodology to determine the quality of the HTS solution. A mixed integer linear programing (MILP) model was developed to evaluate the optimality of the solution of the HTS for a small-size instance that consists of 640 problems. In addition, three dispatching rule heuristic combinations (EDD–EDD, EDD–BATCS and ATC–BATCS) were developed to test the HTS for large-size instances that deals with 1440 problems. The HTS provided comparable results with the MILP for small-size instances and outperformed the developed dispatching heuristics.     

Variable Neighborhood Search strategies for the Order Batching Problem

The Order Batching Problem is an optimization problem belonging to the operational management aspect of a warehouse. It consists of grouping the orders received in a warehouse (each order is composed by a list of items to be collected) in a set of batches in such a way that the time needed to collect all the orders is minimized. Each batch has to be collected by a single picker without exceeding a capacity limit. In this paper we propose several strategies based on the Variable Neighborhood Search methodology to tackle the problem. Our approach outperforms, in terms of quality and computing time, previous attempts in the state of the art. These results are confirmed by non-parametric statistical tests.     

Scheduling jobs with ready times and precedence constraints on parallel batch machines using metaheuristics

In this paper, we discuss a scheduling problem for parallel batch machines where the jobs have ready times. Problems of this type can be found in semiconductor wafer fabrication facilities (wafer fabs). In addition, we consider precedence constraints among the jobs. Such constraints arise, for example, in scheduling subproblems of the shifting bottleneck heuristic when complex job shop scheduling problems are tackled. We use the total weighted tardiness as the performance measure to be optimized. Hence, the problem is NP-hard and we have to rely on heuristic solution approaches. We consider a variable neighborhood search (VNS) scheme and a greedy randomized adaptive search procedure (GRASP) to compute efficient solutions. We assess the performance of the two metaheuristics based on a large set of randomly generated problem instances and based on instances from the literature. The obtained computational results demonstrate that VNS is a very fast heuristic that quickly leads to high-quality solutions, whereas the GRASP is slightly outperformed by the VNS approach. However, the GRASP approach has the advantage that it can be parallelized in a more natural manner compared to VNS.     

Resource Portfolio Planning Methodology for Semiconductor Wafer Manufacturing

Resource portfolio planning is a frequent task in semiconductor wafer fabrication plants, as process, machine and product technologies evolve rapidly and the plants go through capacity expansion. As wafer fabrication plants are complex integrated factories with conspicuous queuing effects, portfolio planning must take into consideration machine use, factory throughput, and total flow-time simultaneously. This paper describes a resource portfolio planning methodology for wafer fabrication foundry plants. An improved static capacity model is first presented. A portfolio planning procedure based on static capacity estimation and queuing analysis is next described. This procedure enables the solution space of resource portfolios to be explored effectively and has demonstrated a capability superior to the current planning method in an industry case study. A software implementation of the procedure is also used to clarify planning dilemmas. It is shown that empirical formulae can be used to estimate the efficiency of batch machines. It is also used to show three types of portfolio adjustment action: flow-time reduction, cost reduction and effectiveness improvement.     

Single machine batch scheduling to minimize total completion time and resource consumption costs

In this paper we study the single-machine batch scheduling problem under batch availability, where both setup and job processing times are controllable by allocating a continuously divisible nonrenewable resource. Under batch availability a set of jobs is processed contiguously and completed together, when the processing of the last job in the batch is finished. We present polynomial time algorithms to find the job sequence, the partition of the job sequence into batches and the resource allocation, which minimize the total completion time or the total production cost (inventory plus resource costs).