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1.
基于CGOM的软件费用模型研究   总被引:5,自引:1,他引:4  
刘宏伟  杨孝宗  曲峰  董剑 《计算机学报》2003,26(10):1332-1336
软件测试是提高软件质量的重要手段,对测试数据充分的测试准则是软件测试完成的标准.目前,绝大多数的测试准则并不考虑软件费用,容易为了满足测试准则而使用户承担昂贵的测试费用.该文提出了一种随机过程类非齐次泊松过程(NHPP)中的经典模型——G-O模型的改进模型,并基于此模型构造了一个综合了软件设计费用、软件测试费用、软件维护费用、软件失效造成的风险损失的软件费用模型.最后从软件费用出发,讨论了软件的最佳发布时间.  相似文献
2.
基于分布式射频MEMS移相器电容开关的分析与设计   总被引:1,自引:1,他引:0  
通过分析MEMS电容开关的工作原理,设计出一种适合分布式射频MEMS移相器电路的新型电容开关.采用Intel lisuiteTM软件优化电容开关的驱动电压、响应时间、释放时间和机械振动模式.结果表明,开关驱动电压为2.5 V、响应时间小于30μs,释放时间大于60 μs和所有振动模式固有频率都大于15 KHz.与普通开关结构比较,该新型电容开关结构具有优越射频机电性能和响应时间,同时也对电容开关的制备工艺进行分析.  相似文献
3.
大规模流水线调度的瓶颈分解算法研究   总被引:1,自引:0,他引:1  
为了克服大规模流水线调度问题的计算复杂度,提出一种瓶颈分解启发式算法.利用瓶颈特性将流水线分解为瓶颈机和非瓶颈机,对瓶颈机建立带有到达时间和传递时间约束的单机调度模型,并优化求解,而在非瓶颈机上则采用简单的分派规则,通过不断修正瓶颈机上工件的到达时间和传递时间来协调瓶颈机与非瓶颈机之间的关联.仿真结果验证了算法的有效性.  相似文献
4.
In scheduling of batch processing machines in the diffusion and oxidation areas of a wafer fabrication facility, it can be found that the processing times of these batching operations can be extremely long (10 h) when compared to other operations (1-2 h) in a wafer fab. Moreover, the jobs to be processed may have different priorities/weights, due dates and ready times. In the presence of unequal ready times, it would be better to wait for future job arrivals in order to increase the fullness of the batch. On the other hand, repeated processing of similar tasks improves workers’ skills. Motivated by these observations, we consider a single-machine problem with the sum of processing times based learning effect and release times. The objective is to find a schedule to minimize the total completion times. We first develop a branch-and-bound algorithm for the optimal solution. Then we propose a simulated-annealing heuristic algorithm for a near-optimal solution. Finally, we conduct a computational experiment to evaluate the performances of the proposed algorithms. The results show that the branch-and-bound algorithm can solve instances up to 24 jobs, and the average error percentage of the simulated-annealing algorithm is less than 0.1482%.  相似文献
5.
6.
This paper addresses scheduling problems for tasks with release and execution times. We present a number of efficient and easy to implement algorithms for constructing schedules of minimum makespan when the number of distinct task execution times is fixed. For a set of independent tasks, our algorithm in the single processor case runs in time linear in the number of tasks; with precedence constraints, our algorithm runs in time linear in the sum of the number of tasks and the size of the precedence constraints. In the multi-processor case, our algorithm constructs minimum makespan schedules for independent tasks with uniform execution times. The algorithm runs in O(n log m) time where n is the number of tasks and m is the number of processors. Received September 25, 1997; revised June 11, 1998.  相似文献
7.
Failure of a safety critical system can lead to big losses.Very high software reliability is required for automating the working of systems such as aircraft controller and nuclear reactor controller software systems.Fault-tolerant softwares are used to increase the overall reliability of software systems.Fault tolerance is achieved using the fault-tolerant schemes such as fault recovery (recovery block scheme),fault masking (N-version programming (NVP)) or a combination of both (Hybrid scheme).These softwares incorporate the ability of system survival even on a failure.Many researchers in the field of software engineering have done excellent work to study the reliability of fault-tolerant systems.Most of them consider the stable system reliability.Few attempts have been made in reliability modeling to study the reliability growth for an NVP system.Recently,a model was proposed to analyze the reliability growth of an NVP system incorporating the effect of fault removal efficiency.In this model,a proportion of the number of failures is assumed to be a measure of fault generation while an appropriate measure of fault generation should be the proportion of faults removed.In this paper,we first propose a testing efficiency model incorporating the effect of imperfect fault debugging and error generation.Using this model,a software reliability growth model (SRGM) is developed to model the reliability growth of an NVP system.The proposed model is useful for practical applications and can provide the measures of debugging effectiveness and additional workload or skilled professional required.It is very important for a developer to determine the optimal release time of the software to improve its performance in terms of competition and cost.In this paper,we also formulate the optimal software release time problem for a 3VP system under fuzzy environment and discuss a the fuzzy optimization technique for solving the problem with a numerical illustration.  相似文献
8.
李曙光  李国君  王秀红 《软件学报》2006,17(10):2063-2068
考虑无界批量机器并行调度中极小化加权完工时间和问题.设有n个工件和m台批加工同型机.每个工件具有一个正权因子、一个释放时间和一个加工时间.每台机器可以同时加工Bn个工件.一个批次的加工时间是该批次所包含的所有工件的加工时间的最大者.在同一批次中加工的工件有相同的完工时间,即它们的共同开始时间加上该批次的加工时间.给出了一个多项式时间近似方案(PTAS).  相似文献
9.
We consider a permutation flow-shop withn jobs andm machines, where the job processing times are given by a monotone nondecreasing function of the time elapsed since the release of the jobs. In this class of discrete event dynamic systems (DEDS), the dynamics is bothevent dependent, andtime dependent. Unless processing times are constant, it cannot be linearized using the (max, +) algebra. In order to schedule the jobs, we first need to know how to compute the (optimal) value of each schedule, i.e., when the jobs should be released. This optimal control problem is solved here by proving apredictive feedback control law, which holds for any regular performance criterion. Then we derive aBellman principle for this type of DEDS, and prove closed form control formulas for the minimum of: the makespan (C max), the maximum lateness (L max), and the maximum tardiness (T max). We also prove some minimax theorems for a class of nonconvex maps derived from the dynamics of the system. The optimal control problem is solved in polynomial time, provided the inverse of the processing time functions can be computed in polynomial time.Research supported by the M.E.S.S. Québec Actions Structurantes, F.C.A.R. 86CE-130, 89EQ3528, NRC grants OGP38915, OGP37148, the Belgian Program on Interuniversity Poles of Attraction, and the CNRS, France.  相似文献
10.
We consider a single machine scheduling problem with resource dependent release times that can be controlled by a non-increasing convex resource consumption function. The objective is to minimize the weighted total resource consumption and sum of job completion times with an initial release time greater than the total processing times. It is known that the problem is polynomially solvable in O(n4) with n the number of jobs.  相似文献
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