• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.2
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• pp.99-107
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• 2007

We consider (worst-case) robust optimization versions of the Economic Order Quantity (EOQ) model with decreasing cost functions. Two variants of the EOQ model are discussed, in which the purchasing costs are decreasing power functions in either the order quantity or demand rate. We develop the corresponding worst-case robust optimization models of the two variants, where the parameters in the purchasing cost function of each model are uncertain but known to lie in an ellipsoid. For the robust EOQ model with the purchasing cost being a decreasing function of the demand rate, we derive the analytical optimal solution. For the robust EOQ model with the purchasing cost being a decreasing function of the order quantity, we prove that it is a convex optimization problem, and thus lends itself to efficient numerical algorithms.

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.227-230
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• 2002

This paper presents an analytic method of quality function deployment(QFD) that is to maximize customer satisfaction subject to technical and economic sides in process design. We have used Wasserman's normalization method and the analytical hierarchy process(AHP) to determine the intensity of the relationship between customer requirements and process design attributes. This paper also shows cost-quality model the tradeoff between quality and cost as a linear programming(LP) with new constraints that have designated special process required allocating firstly The cost-quality function deployment of piston ring is presented to illustrate the feasibility of such techniques.

• Journal of the Korea Safety Management & Science
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• v.4 no.2
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• pp.169-178
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• 2002

This paper presents an analytic method of quality function deployment(QFD) that is to maximize customer satisfaction subject to technical and economic sides in process design. We have used Wasserman's normalization method and the analytical hierarchy process(AHP) to determine the intensity of the relationship between customer requirements and process design attributes. This paper also shows cost-quality model the tradeoff between quality and cost as a linear programming(LP) with new constraints that have designated special process required allocating firstly. The cost-quality function deployment of piston ring is presented to illustrate the feasibility of such techniques.

• Korean Management Science Review
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• v.20 no.2
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• pp.179-196
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• 2003

Function point model is the international standard method to measure the software size which is one of the most important factors to determine the software development cost. Function point model can successfully be applied only when the detailed specification of users' requirements is available. In the domestic public sector, however, the budgeting for software projects is carried out before the requirements of softwares ere specified in detail. Therefore, an efficient function point estimation method is required to apply function point model at the early stage of software development projects. The purpose of this paper is to compare various function point estimation methods and analyse their accuracies in domestic software projects. We consider four methods : NESMA model, ISBSG model, the simplified function point model and the backfiring method. The methods are applied to about one hundred of domestic projects, and their estimation errors are compared. The results can used as a criterion to select an adequate estimation model for function point counts.

• The KIPS Transactions:PartD
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• v.11D no.3
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• pp.597-604
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• 2004

Accurate software cost estimation is essential to both developers and customers. Most of the cost estimating models based on the size measure methods, such as LOC and FP, are obtained through size estimation. The accuracy of size estimation directly influences the accuracy of cost estimation. As a result, the overall structure of regression-based cost models applies the power function based on software size. Many growth phenomenon in nature such as the growth in living organism, performance of technology, and learning capability of human show an S-shaped curve. This paper proposes a model which estimates the developing effort by using the growth curve. The presented model assumes that the relation cost and size follows the growth curve. The appropriateness of the growth curve model based on Function Point, Full-Function Point and Use-Case Point, which are the general methods in estimating the software size have been confirmed. The proposed growth curve model shows similar performance with power function model. In conclusion, the growth curve model can be applied in the estimation of the software cost.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.640-643
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• 1987

A probabilistic production costing model based on the economic load dispatch has been developed. Objective function is composed of fuel cost which is a function of generation output and the failure cost. Coefficients of the failure cost is determined from the known equivalent generation cost. The model is compared with other existing methodolgies and the excellent results are obtained.

• KIEAE Journal
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• v.9 no.1
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• pp.107-113
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• 2009

The energy cost is resulted from the energy use. Its sources are divided into some types and depended on the building use or energy-use type. The energy cost should be affected by the amount of the energy use. The cost could be calculated to consider various factors such as the insulation, heating type, building shape and others. But it can not consider all of the affect factors to the energy cost and need to categorize the factors to the condition for estimating the cost. In this paper, it aimed at providing the estimation model in linear equation and multiple linear regression, utilizing the building exterior condition and management characteristics in apartment housing. Its survey are conducted in two parts of management characteristics and building exterior condition. The correlation analysis is conducted to get rid of the multicolinearity among the inputted factors. The number of linear equation model is 11 and includes the 1st, 2nd and 3rd equation function, power function and others. Among these, it suggested the 2nd and 3rd function and power function in terms of the statistics. In multiple linear regression model, the building volume and management area are inputted to the estimation.

• The Journal of Fisheries Business Administration
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• v.49 no.4
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• pp.19-36
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• 2018

Overstock in aquaculture is a matter of concern in aquaculture management. To sort fish based on fingerling size in case of overstocking is an important problem in aquaculture farm. This study aims to determine the amount of fry overstock and sorting time in aquaculture farm. This study builds a mathematical model that finds the value of decision variables to optimize objective function summing up the fingerling purchasing cost, aquaculture farm operating cost and feeding cost under mortality and farming period constraints. The proposed mathematical model involves following biological and economical variables and coefficients: (1) number of fingerlings, (2) sorting time, (3) fish growth rate and variation, (4) mortality, (5) price of a fry (6) feeding cost, and (7) possible sorting periods. Numerical simulation is presented herein. The objective of numerical simulation is to provide decision makers to analyse and comprehend the proposed model. When extensive biological data about growth function of fry becomes available, the proposed model can be widely applicable to real aquaculture farms.

• KIEAE Journal
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• v.15 no.1
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• pp.69-75
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• 2015

Building has required the repair money to improve or maintain the decent living condition continuously after construction. It needs to grasp the building deterioration to decide the scope and contents before it is repaired. Under various conditions such as physical, social and financial constraints, the repair plan would be prepared. Among constraints, the cost is indispensible to specify the repair time, repair scope and target. The required cost would be planned to preparation over the years. In this paper, it aimed at providing the repair strategy of the public rental housing in repair time, using the cumulative cost model which is $3^{rd}$ function. In the $3^{rd}$ function, the inflection point should exist in the line. And there are two types in the cumulative model, First, if the maximum cost be shown, the repair time would be provided. Second, if the maximum cost not be shown, the cumulative function should be proportionally increased and the repair strategy is properly provided with a short cycle. In results of this study, 11 items would provide the repair time. These cumulative function would be repaired about 4 years after constructed, and after about 4 years, the cumulative function would be continuously increased.

• The Journal of Fisheries Business Administration
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• v.51 no.3
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• pp.17-31
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• 2020

The purpose of this study is to identify economic situation on scale of tuna distant longline fishery by analyzing its economies of scale using the cost function. To analyze its economics of scale, the deep-sea fishing statistics were used from 2012 to 2016. In detail, the number of panels for estimating the cost function was 68 tuna distant longline vessels from 2012 to 2016, and the total number of observations over the five years were 340. As a final model, the two-way fixed effect model based on the translog cost function was adopted through the F test, the Breusch-Pagan test and the Hausman test. As a result of the analysis, it was found that tuna distant longline fishery between 2012 and 2014 was diseconomies of scale, the fishery between 2015 and 2016 was economies of scale. However, the economic indicators of the scale from 2012 to 2016 were almost close to zero, indicating that the constant returns to scale, the optimal scale, were reached. Therefore, in the situation where the amount of fishery resources in the world continues to decrease, it is necessary to prepare a method to obtain economic benefits through scale maintenance and reduction rather than indiscriminate scale expansion.