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Information system design and sizing constitute a complex, top-down process that tailors the technology architecture to application requirements. Practitioners usually tackle this top-down process by focusing on individual design aspects, such as data or specific applications, and by relying on their previous experiences to compare alternative architectural solutions. Acquisition costs are usually accounted for, but related operating and maintenance costs are often neglected or underestimated. The complexity of optimizing individual design problems leads researchers to avoid a global optimization perspective and, thus, the IS architecture is usually a result of the juxtaposition of multiple local optima.This paper takes an overall perspective on the cost minimization problem of information system design to achieve a better trade-off between cost and performance over the whole expected life of the technology architecture. A comprehensive design methodology is discussed as an integrating framework that accounts for all categories of costs, including design, implementation, maintenance, and operation, to achieve a globally cost-minimizing solution. 相似文献
43.
定宽压力机(SP)同步控制原理及调试 总被引:1,自引:0,他引:1
针对鞍钢1780机组引进的日本IHI开发的定宽大侧压新技术,对其侧压模块运动轨迹的高精度控制进行分析,并对其同步控制及调试进行了说明. 相似文献
44.
以GA301型浆纱机的恒张力卷绕系统为例,介绍了PUX3无级变速器的主要技术参数和作用原理.针对PUX3无级变速器在浆纱机运转中经常出现的机械故障进行分析,从安装和调整两方面讨论了卷绕张力的精确控制问题. 相似文献
45.
Yang Honghong Wu ZhimingDepartment of Automation Shanghai Jiaotong University Shanghai China 《机械工程学报(英文版)》2003,16(1):21-24
The capacitated lot sizing and scheduling probbm that involves in determining the production amounts and release dates for several items over a given planning horizon are given to meet dynamic order demand without incurring backloggings. Thi: problem considering overtime capacity is studied. The mathematical model is presented, and a genelic algorithm (GA) approach is developed to solve the problem. The initial solutions are generated after using heuristic method. Capacity balancing procedure is employed to stipulate the feasibility of the solutions. In addition, a technique based on Tabu search (TS) is inserted into the genetic algorithm to d;al with the scheduled overtime and help the convergence of algorithm. Computational simulation is conducted to test the efficiency of the proposed hybrid approach, which turns out to improve both the solution quality and execution speed. 相似文献
46.
A baseline-free quantitative sizing methodology utilizing ultrasonic guided waves for fatigue cracks under welded stiffeners in steel bridge decks has been developed. An inverse wavefield extrapolation-based formulation for obtaining the crack reflectivity and depth profile has been presented in the kernel of which, the presence of welded orthogonal stiffeners has been accounted for. Having conducted experiments on a test bridge deck subject to fatigue loading, it has been demonstrated that the crack profile can be estimated from the reflection coefficients obtained. In comparison with the reference measurements, the maximum crack depth estimation error turned out to be about 20%. 相似文献
47.
This paper presents a novel optimization method for sizing and design of stand alone photovoltaic systems. Loss of power supply probability analysis is set as a benchmark to determine all possible PV array and battery capacity. Then, the optimum design is proposed based on the lowest levelized cost of energy. The case study, with reference to Malaysia's meteorological data and typical load profile of rural area, has been simulated and compared to selected three past researches. 相似文献
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Hakan F. Karagul Donald P. Warsing Jr. Thom J. Hodgson Maaz S. Kapadia 《国际生产研究杂志》2013,51(23):7064-7084
We propose a novel mixed integer programming formulation for the capacitated lot-sizing problem with set-up times and set-up carryover. We compare our formulation to two earlier formulations, the Classical and Modified formulations, and a more recent formulation due to Suerie and Stadtler. Extensive computational experiments show that our formulation consistently outperforms the Classical and Modified formulations in terms of CPU time and solution quality. It is competitive with the Suerie–Stadtler (S&S) formulation, but outperforms all other formulations on the most challenging instances, those with low-capacity slack and a dense jobs matrix. We show that some of the differences in the performance of these various formulations arise from their different use of binary variables to represent production or set-up states. We also show that the LP relaxation of our Novel formulation provides a tighter lower bound than that of the Modified formulation. Our experiments demonstrate that, while the S&S formulation provides a much tighter LP bound, the Novel formulation is better able to exploit the intelligence of the CPLEX solution engine. 相似文献
50.
结合自主研发的预湿浆纱机及多年来的实际应用经验,概述了预湿上浆的工艺机理,总结、分析了预湿上浆技术的应用状况,表明预湿上浆是有待推广应用的先进技术。 相似文献