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Известия ТРТУ
Тематический выпуск
placement task happens to differ from the well known block linear placement problem which has been deeply studied so far since the common linear placement deals with the set of connected blocks with specified set of their feasible implementations .
There are some important properties of the task of linear placement of subcells with unknown implementations:
♦ It has very high impact on resulting layout quality since it affects both levels of the circuit hierarchy;
♦ There is no obvious quality criteria for this task;
♦ The linear placement deals with layout domain while there is no layout-related data in the task input (neither subcell geometries nor dimensions etc.);
We propose few approximation heuristics for obtaining the data necessary to solve this linear placement problem.
We have also developed the vectorial quality metric which allows us successfully apply any iterative optimization algorithm suitable to solve the task. This metric comprises of two widely used criteria - weighted cut value and the wire length estimate. We have found that use of any one of these criteria as a standalone quality metric may not lead to desirable quality of results due to properties of the optimization task and subop-timal nature of algorithms applied on it.
Our experiments show that even simple force-directed relaxation heuristic (like the one proposed by Goto and adopted to linear placement) may produce very good results with use of our quality metric. In 80% of experiments our implementation has reached global minima.
Some ideas on how to extend our heuristics to achieve better results are also presented.
LITERATURE
1. Y.G.Saab, “An Improved Linear Placement Algorithm Using Node Compaction”, IEEE Trans. on CAD of Integrated Circ. and Syst., Vol.15 No.8, August 1996, pp. 952-958.
2. S.Goto, “An efficient algorithm for the two-dimensional placement problem in electrical circuit layout”, IEEE Trans. on Circuits and Systems, CAS-28, Jan. 1981, pp. 12-18.
УДК 681.32
Hassan Farsijani1
EVOLUTIONARY METHODS FOR DESIGN OF GLOBAL WORLD-CLASS MANUFACTURING FOR THE WORLD MARKET
Abstract. The importance of the overview of earlier management theory and thought is the recognition of scholars contributions and impacts on modern managerial practices. World-Class manufacturing techniques is one of the most talked about manufacturing management approaches of the 1987 and will be a major management focus and trend in the 21s century. The concept of global world-class manufacturing has become the single most motivating theory in many major industries for world market.
The range of techniques associated with competitive manufacturing has expanded rapidly since the inception of MRP in the early 1960s. These techniques integrated into
1 Department of Industrial Management Shahid Beheshti University, Tehran, Iran E-mail: [email protected]
Материалы Международной конференции
“Интемектуальные САПР”
the generic term world-class manufacturing(WCM). However, the range and sophistication of these techniques places WCM status beyond the aspirations and competence of many companies. Companies progress by stages toward the desired goal of global competitiveness manufactures will have to achieve world-class manufacturing status to compete effectively in global markets.
Schonberger (1987) coined the term WCM to cover the many techniques and technologies designed to enable a company to match its best competitors. Within the various professional manufacturing attention is being paid to reliability, dependent on the stage of professionalisation, there are all kind of facilities for increasing the system design of world-class manufacturing. WCM is now becoming more an area for explicit attention for all kind of manufacturing. The new concept of designing global products for global markets has emerged in the 21 century. The design of global products for global markets entails a major shift in both marketing and design philosophies for most manufacturing companies. Manufacturers worldwide are having to adapt to new conditions of world market and to new definitions of world-class performance.
Global WCM is a management philosophy that emphasises the need to meet external and internal customers needs and expectations and the importance of doing things right for world market. Reliability, quality and cost are linked, higher quality being associated with higher reliability. The reliability of items, products and facilities is an important consideration of design by world-class manufacturing techniques. WCM techniques have an important role to play in world market. Global WCM techniques are a competitive strategy involving continuous improvement of products, processes and services to improve quality, reduce costs, increase productivity and increase total customer satisfaction.
The paper is based on an ongoing research programme designed to identify how the concept of world-class manufacturing techniques can be made more relevant to achieve world market. The question in this paper is which problems the management of manufacturing may encounter when it wants to organise the global WCM management of the professional manufacturing more systematically for world market. These problems such as, determining world-class manufacturing norms, developing a world-class management methodology for world market, the demonstrability of world-class manufacturing in the professional manufacturing. The paper uses a case study to illustrate its findings based on company experiencing both rapid growth and increasing international competition.
УДК 007.001.33
А.М. Наместников
ПРИМЕНЕНИЕ АДАПТИРОВАННОГО ГЕНЕТИЧЕСКОГО АЛГОРИТМА ДЛЯ РЕШЕНИЯ ЗАДАЧ РАЗМЕЩЕНИЯ
Генетический алгоритм является эффективной процедурой оптимизации при решении широкого класса оптимизационных задач. Тем не менее, в случае много-экстремальности функции оптимизации, часто не удается найти эффективные ре, -
.
электрорадиоэлементов (ЭРЭ) на непрерывном монтажном пространстве.
Исходными данными для решения задачи размещения разногабаритных ЭРЭ являются: габариты монтажного пространства; множество элементов размещения,
