• 아태비즈니스연구
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• 제9권2호
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• pp.15-37
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• 2018

The purpose of this paper was to explain on the conceptualisation of the Halal Orientation strategy (HOS) based on operation strategy perspective. The four variables constitute in HOS are staffing, materials, production process and storage together with transportation. By focusing on HOS, the manufacturers reinforce improvement in quality, cost control, time and flexibility of the production Halal food industry in Malaysia which is the performance objective of market competitiveness in Malaysia context. A self-administered questionnaire was designed and used to assess the significant of HOS that lead to improve quality, cost control, reduction in time and the flexibility among Halal food manufacturers in Malaysia. From a total of 443 Halal food manufacturers were involved in this study, only 137 respondents are usable for this research. The study showed significant results for the manufacturers to focus in Halal Orientation strategy (HOS) which have positive impacts on quality, cost control, time and flexibility. This research aimed to measure the HOS among food firms in Malaysia and to determine HOS in relation with the performance objective of operational outcomes.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.458-466
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• 2011

In war time, minimizing the logistics response time for supporting military operations is strongly needed. In this paper, i propose the mathematical formulation for minimizing the maximal acquisition completion time in wartime or during a state of emergency. The main structure of this formulation is based on the traveling purchaser problem (TPP), which is a generalized form of the well-known traveling salesman problem (TSP). In the case of the general TPP, an objective function is to minimize the sum of the traveling cost and the purchase cost. However, in this study, the objective function is to minimize the traveling cost only. That's why it's more important to minimize the traveling cost (time or distance) than the purchase cost in wartime or in a state of emergency. I generate a specific instance and find out the optimal solution of this instance by using ILOG OPL STUDIO (CPLEX version 11.1).

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1654-1666
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• 2024

The goal of this research is to propose a way to maximize small modular reactor (SMR) utilization to gain better market feasibility in support of carbon neutrality. For that purpose, a comprehensive tool was developed, combining off-design thermohydraulic models, economic objective models (levelized cost of electricity, annual profit), non-economic models (saved CO2), a parameter input sampling method (Latin hypercube sampling, LHS), and a multi-objective evolutionary algorithm (Non-dominated Sorting Algorithm-2, NSGA2 method) for optimizing a SMR-combined heat and power cycle (CHP) system design. Considering multiple objectives, it was shown that NSGA2+LHS method can find better optimal solution sets with similar computational costs compared to a conventional weighted sum (WS) method. Out of multiple multi-objective optimal design configurations for a 105 MWe design generation rating, a chosen reference SMR-CHP system resulted in its levelized cost of electricity (LCOE) below $60/MWh for various heat prices, showing economic competitiveness for energy market conditions similar to South Korea. Examined economic feasibility may vary significantly based on CHP heat prices, and extensive consideration of the regional heat market may be required for SMR-CHP regional optimization. Nonetheless, with reasonable heat market prices (e.g. district heating prices comparable to those in Europe and Korea), SMR can still become highly competitive in the energy market if coupled with a CHP system.

• 한국ITS학회 논문지
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• 제11권5호
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• pp.70-77
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• 2012

교통약자들을 위한 차량서비스는 dial-a-ride, demand responsive 또는 paratransit으로 불리며 미국과 유럽에서 널리 제공되고 있는 대중교통의 하나이다. 본 연구는 이러한 교통약자 차량서비스의 배차와 차량경로문제에 관한 것으로 다수차고지와 예약시간 위반을 고려한다. 본 연구에서는 기존의 연구에서 제안된 clustering first-routing second에 기초한 휴리스틱 알고리즘을 실제 큰 규모의 교통약자 차량서비스에 적용하였다. 사례연구로서 Maryland Transit Administration (MTA)의 교통약자 차량서비스를 소개하고 실제 MTA의 운영결과와 제안된 휴리스틱 알고리즘의 결과를 비교하였다. 제안된 모형의 목적함수는 서비스제공자의 비용과 고객들의 불편비용으로 이루어진 전체비용을 최소화하는 것이다. 실제 MTA의 운영자료에 차량대기시간, 서비스지연시간과 초과승차시간에 대한 정보가 없는 관계로 비교를 위해서 clustering first-routing second에 기초한 휴리스틱 알고리즘의 목적함수 값은 차량의 대기비용, 고객들의 서비스지연비용과 초과 승차시간 비용를 포함하지 않는다. MTA의 실제운영에 의한 목적함수 값보다 HCR의 목적함수 값이 보다 나은 것으로 나타났으며 이 결과는 본 연구에서 제안된 휴리스틱 방법이 실제운영을 보다 효율적으로 바꿀 수 있음을 보여준다.

• Wind and Structures
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• 제8권5호
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• pp.343-356
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• 2005

Overhead sign support structures number in the tens of thousands throughout the trunk-line roadways in the United States. A recent two-phase study sponsored by the National Cooperative Highway Research Program resulted in the most significant changes to the AASHTO design specifications for sign support structures to date. The driving factor for these substantial changes was fatigue related cracks and some recent failures. This paper presents the method and results of a subsequent study sponsored by the Michigan Department of Transportation (MDOT) to develop a relative performance-based procedure to rank overhead sign support structures around the United States based on a linear combination of their expected fatigue life and an approximate measure of cost. This was accomplished by coupling a random vibrations approach with six degree-of-freedom linear dynamic models for fatigue life estimation. Approximate cost was modeled as the product of the steel weight and a constructability factor. An objective function was developed and used to rank selected steel sign support structures from around the country with the goal of maximizing the objective function. Although a purely relative approach, the ranking procedure was found to be efficient and provided the decision support necessary to MDOT.

• Structural Engineering and Mechanics
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• 제23권1호
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• pp.29-42
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• 2006

This paper describes the design scheme of the three-dimensional structures based on the concept of the cellular automata simulation. The cellular automata simulation is performed according to the local rule. In this paper, the local rule is derived in the mathematical formulation from the optimization problem. The cell density is taken as the design variable. Two objective functions are defined for reducing the total weight of the structure and obtaining the fully stressed structure. The constraint condition is defined for defining the local rule. The penalty function is defined from the objective functions and the constraint condition. Minimization of the penalty function with respect to the design parameter leads to the local rule. The derived rule is applied to the design of the three-dimensional structure first. The final structure can be obtained successfully. However, the computational cost is expensive. So, in order to reduce the computational cost, the material parameters $c_1$ and $c_2$ and the value of the cell rejection criterion (CRC) are changed. The results show that the computational cost depends on the parameters and the CRC value.

• 대한토목학회논문집
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• 제28권2A호
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• pp.223-231
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• 2008

이 논문에서는 교량의 유지보수비용을 최소화할 뿐만 아니라 교량의 성능을 동시에 최대화할 수 있는 새로운 유지보수계획법을 제시한다. 교량 수명연한 동안의 유지보수비용과 교량의 바닥판, 주형, 하부구조의 상태등급으로 표현되는 교량의 성능을 동시에 최적화 하는 다목적 최적화 문제를 구성하여 최적의 유지보수계획을 수립한다. 다목적 최적화문제의 해를 얻기 위한 수치해석 방법으로 유전자 알고리즘(Genetic Algorithm, GA)을 사용하고, 다목적 최적화방법을 적용하여 얻어진 여러 개의 해집합 중 최적해의 선택을 위한 의사결정(decision making)을 위해 선호도기반 최적화방법을 적용한다. 일반적인 5경간의 PSC I형 교량에 대한 수치예제를 통해, 이 연구에서 제안하는 방법이 유지보수비용 및 교량성능간의 균형 있는 최적화를 이룰 수 있음을 보인다.

• 상하수도학회지
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• 제34권5호
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• pp.311-321
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• 2020

In this study, a model to optimize residual chlorine concentrations in a water supply system was developed using a multi-objective genetic algorithm. Moreover, to quantify the effects of optimized residual chlorine concentration management and to consider customer service requirements, this study developed indices to quantify the spatial and temporal distributions of residual chlorine concentration. Based on the results, the most economical operational method to manage booster chlorination was derived, which would supply water that satisfies the service level required by consumers, as well as the cost-effectiveness and operation requirements relevant to the service providers. A simulation model was then created based on an actual water supply system (i.e., the Multi-regional Water Supply W in Korea). Simulated optimizations were successful, evidencing that it is possible to meet the residual chlorine concentration demanded by consumers at a low cost.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1838-1854
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• 2023

This paper presents a hybrid algorithm to solve the multi-objective path planning (MOPP) problem for mobile robots in a static nuclear accident environment. The proposed algorithm mimics a real nuclear accident site by modeling the environment with a two-layer cost grid map based on geometric modeling and Monte Carlo calculations. The proposed algorithm consists of two steps. The first step optimizes a path by the hybridization of improved ant colony optimization algorithm-modified A^* (IACO-A^*) that minimizes path length, cumulative radiation dose and energy consumption. The second module is the high radiation dose rate avoidance strategy integrated with the IACO-A^* algorithm, which will work when the mobile robots sense the lethal radiation dose rate, avoiding radioactive sources with high dose levels. Simulations have been performed under environments of different complexity to evaluate the efficiency of the proposed algorithm, and the results show that IACO-A^* has better path quality than ACO and IACO. In addition, a study comparing the proposed IACO-A^* algorithm and recent path planning (PP) methods in three scenarios has been performed. The simulation results show that the proposed IACO-A^* IACO-A^* algorithm is obviously superior in terms of stability and minimization the total cost of MOPP.

• 한국경영과학회지
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• 제30권2호
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• pp.185-199
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• 2005

With the growth of internet shopping malls, there is increasing interest in comparison shopping mall. However most comparison sites compare only book prices by collecting simple XML data and do not provide .the exact comparison Including precise shipping costs. Shipping costs vary depending on each customer's address, the delivery method, and the category of selected goods, so rule based system is required in order to calculate exact shipping costs. Therefore, we designed and implemented comparison shopping mall which compares not only book prices but also shipping costs using rule based inference. By adopting the extensible Rule Markup language (XRML) approach, we proposed the methodology of extracting delivery rules from Web pages of each shopping mall. The XRML approach can facilitate nearly automatic rule extraction from Web pages and consistency maintenance between Web pages and rule base. We developed a ConsiderD system which applies our rule acquisition methodology based on XRML. The objective of the ConsiderD system is to compare the exact total cost of books including the delivery cost over Amazon.com, BarnesandNoble.com, and Powells.com. With this prototype, we conducted an experiment to show the potential of automatic rule acquisition from Web pages and illustrate the effect of delivery cost.