• Journal of Mechanical Science and Technology
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• v.14 no.6
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• pp.655-665
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• 2000

We propose an efficient algorithm for the purpose of satisfying a wide range of design constraints represented with equality and inequality equations as well as production rules. The algorithm employs simulated-annealing and a production rule inference engine and works on design constraints represented with networks. The algorithm fulfills equality constraints through constraint satisfaction processes like variable elimination while taking into account inequality constraints and inferring production rules. It can also reduce the load of the optimization procedure if necessary. We demonstrate the implementation of the algorithm with the result on machine tool design.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.11
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• pp.1680-1688
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• 2008

Development of village chicken production can be a sustainable way of helping to meet the welfare needs of rural populations and raise their living standards. There is a dearth of information on research conducted to characterize, understand and develop the village chicken production systems in Zimbabwe. This review focuses on constraints, opportunities and research needs for the improvement of village chicken productivity in Zimbabwe. Village chicken production in Zimbabwe is extensive and dominated by indigenous chickens that exhibit remarkable adaptation to local environments. The multitude functions of village chickens, which include the provision of high quality protein meat and eggs, cash through sales and socio-cultural roles, are discussed in detail. Human gender aspects in village chicken production are highlighted. The factors that hamper village chicken productivity are reviewed together with opportunities and research needs. The major constraints include shortage of feed, poor health and housing management. Any improvements in these constraints may lead to sustainable increase in village chicken productivity.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1114-1116
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• 1999

This paper presents a new algorithm which evaluates production cost and reliability indices under various constraints of the thermal generation system. In order to consider the operational constraints of thermal units effectively, the proposed algorithm is based on Monte Carlo techniques instead of analytical ones which have difficulty in modelling the units with additional constraints. At that point, generating units are modelled into two types, base load units and peaking units. These generating unit models are used in state duration sampling simulation for which approach can readily consider the peaking unit operating cycles and easily calculates frequency-duration indices. The proposed production simulation algorithm is applied to the IEEE Reliability Test System, and performs the production simulation under the given constraints. The results show that the proposed algorithm is accurate, reliable and useful.

• Journal of Computational Design and Engineering
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• v.2 no.2
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• pp.105-112
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• 2015

Product Lifecycle Management (PLM) ranges from design concepts of products to disposal. In this paper, we focus on the production planning phase in PLM, which is related to process planning and production scheduling and so on. In this study, key decisions for the creation of production plans are defined as production-planning attributes. Production-planning attributes correlate complexly in production-planning problems. Traditionally, the production-planning problem splits sub-problems based on experiences, because of the complexity. In addition, the orders in which to solve each sub-problem are determined by priorities between sub-problems. However, such approaches make solution space over-restricted and make it difficult to find a better solution. We have proposed a representation of combinations of alternatives in production-planning attributes by using Zero-Suppressed Binary Decision Diagrams. The ZDD represents only feasible combinations of alternatives that satisfy constraints in the production planning. Moreover, we have developed a solution search method that solves production-planning problems with ZDDs. In this paper, we propose an approach for managing solution candidates by ZDDs' network for addressing larger production-planning problems. The network can be created by linkages of ZDDs that express constraints in individual sub-problems and between sub-problems. The benefit of this approach is that it represents solution space, satisfying whole constraints in the production planning. This case study shows that the validity of the proposed approach.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.793-796
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• 1996

This study proposes a new algorithm which performs a production simulation under various constraints and maintains computational efficiency. In order to consider the environmental and operational constraints, the proposed algorithm is based on optimization techniques formulated in LP form In the algorithm, "system characteristic constraints" reflect the system characteristics such as LDC shape, unit loading order and forced outage rate. By using the concept of Energy Invariance Property and two operational rules i.e. Compliance Rule for Emission Constraint, Compliance Rule for Limited Energy of Individual Unit, the number of system characteristic constraints is appreciably reduced. As a solution method of the optimization problem, the author uses Karmarkar's method which performs effectively in solving large scale LP problem. The efficiency of production simulation is meaningful when it is effectively used in power system planning. With the proposed production simulation algorithm, an optimal expansion planning model which can cope with operational constraints, environmental restriction, and various uncertainties is developed. This expansion planning model is applied to the long range planning schemes by WASP, and determines an optimal expansion scheme which considers the effect of supply interruption, load forecasting errors, multistates of unit operation, plural limited energy plants etc.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.104-113
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• 2001

Smallholder dairy production systems in developing countries are discussed with reference to type of systems, their characteristics, potential, and opportunities for improvement. Three types of dairy systems are identified and described: smallholder systems, smallholder cooperative dairy production systems, and intensive dairy production systems. The first two systems are by far the most important, and are associated with increasing intensification. Buffaloes are especially important in South Asia, but elsewhere dairy production mainly involves Holstein-Friesian cross-bred cattle. Dairy goats are important in some countries, but are generally neglected in development programmes. The expansion and intensification of smallholder dairy production is fueled by increased demand for milk with associated problems of milk handling and distribution, hygiene and environmental pollution. The major constraints to production are inter alia, choice of species, breeds and availability of animals; feed resources and improved feeding systems; improved breeding, reproduction, and animal health care; management of animal manure, and organised marketing, and market outlets. These constraints provide major opportunities and challenges for research and development to increase dairy production, efficient management of natural resources, and improved livelihoods of poor farmers. Specific areas for research are identified, as also the need of a holistic focus involving interdisciplinary research and integrated natural resource management, in a shared partnership between farmers and scientists that can demonstrate increased productivity and sustainable production systems. Suggestions for performance indicators in smallholder dairy production systems are indicated.

• Journal of the Korean Operations Research and Management Science Society
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• v.10 no.2
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• pp.15-23
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• 1985

A multi-product multi=facility production planning model is in which known demands must be satisfied. The model considers concave production costs and piecewise concave inventory costs in the introduction of production capacity constraints. Backlogging of unsatisfied demand is permitted. The structure of optimal production schedules is characterized and then used to solve an illustrative numerical problem.

• IE interfaces
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• v.14 no.4
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• pp.356-364
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• 2001

Production Improvement Method in TOC consists of five steps, but it is very difficult for most firms to implement it because it lacks the detailed methods at each step. This paper suggests some of detailed methods to implement the TOC. In the first step, computer simulation is used to identify the constraints in production lines. Subsequently, ASP, AUT, and CM calculation are defined for the second step, which are helpful to exploit the company's constraints. We also suggest the OEE method to effectively exploit the constraints of production lines in the factory. Finally the TOC/OEE procedure is suggested to optimize the investment in the fourth step. As an illustrative example, we introduce a case of a wafer manufacturer to adopt the suggested methods. The benefits of implementating the suggested methods are addressed in the framework of the balanced scorecard.

• IE interfaces
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• v.16 no.3
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• pp.352-361
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• 2003

Vehicle manufacturing plant is a typical mixed-model production system. Generally it consists of three main shops including body shop, painting shop and assembly shop in addition to engine shop. Each shop contains diverse manufacturing processes, all of which are integrated in a form of flow line. Due to the high pressure from the market requesting small-volume large variety production, production planning becomes very critical for the competitiveness of automotive industry. In order to save costs and production time, production planning system is requested to meet some designated requirements for each shop: to balance the work load in body and assembly shops, and to minimize the number of color changes in painting shop. In this context, we developed a sequencing module for a vehicle production planning system using the ILOG Solver Library. It is designed to take into account all the manufacturing constraints at a time with meeting hard constraints in body shop, minimizing the number of soft constraints violated in assembly shop, and minimizing the number of color changes in painting shop.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.113-116
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• 1995

In this study, we formulate production costing problem with environmental and operational constraints into an optimization problem of LP form. In the process of formulation, auxiliary constraints on which reflect unit loading order are constructed to reduce the size of optimization problem by economic operation rules. As a solution of the optimization problem in LP form, we use Karmarkar's method which performs much faster than simplex method in solving large scale LP problem. The proposed production costing algorithm is applied to IEEE Reliability Test System, and performs production simulation under environmental and operational constraints. Test and computer results are given to show the accuracy and usefulness of the proposed algorithm in the field of power system planning.