• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.239-250
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• 2014

The purpose of this research is to implement and develop the Economic Cost Driver Size(ECDS) extended model to determine the optimal cash driver size with measurement complexity cost and allocation fail cost. ECDS model can be used to seek both measurement accuracy and time efficiency of the Activity-Base Costing (ABC). The study also develops Activity Priority Number (APN) to evaluate the importance of nonvalue-added activities improvement and to determine the representative cost driver of value-added activities when applying ECDS model. APN consists of Severity Priority Number (SPN), Undetectablitiy Priority Number (UPN) and Occurrence Priority Number (OPN). APN can be obtained from lower-stream activity, current activity, upper-stream activity in terms of hierarchical dependency of SIPOC (Supplier, Input, Process, Output, and Customer). In order to seek both efficiency of invested capital and reduction of overhead cost, the paper proposes the integrated ABC and Economic Value Added (EVA) model using redesigned ABC-based statement of comprehensive income and EVA-based statement of financial position. For a better understanding of the proposed ABC-EVA integrated model, numerical examples are demonstrated in this paper. Cost drivers of ABC and capital drivers of EVA in the proposed model can be used to reduce activity overhead cost from ABC-based statement of comprehensive income and to lessen activity capital charge from EVA-based statement of financial position.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.4776-4798
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• 2015

The location selection of virtual machines in distributed cloud is difficult because of the physical resource distribution, allocation of multi-dimensional resources, and resource unit cost. In this study, we propose a multi-object virtual machine location selection algorithm (MOVMLSA) based on group information, doubly linked list structure and genetic algorithm. On the basis of the collaboration of multi-dimensional resources, a fitness function is designed using fuzzy logic control parameters, which can be used to optimize search space solutions. In the location selection process, an orderly information code based on group and resource information can be generated by adopting the memory mechanism of biological immune systems. This approach, along with the dominant elite strategy, enables the updating of the population. The tournament selection method is used to optimize the operator mechanisms of the single-point crossover and X-point mutation during the population selection. Such a method can be used to obtain an optimal solution for the rapid location selection of virtual machines. Experimental results show that the proposed algorithm is effective in reducing the number of used physical machines and in improving the resource utilization of physical machines. The algorithm improves the utilization degree of multi-dimensional resource synergy and reduces the comprehensive unit cost of resources.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.245-251
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• 2016

This paper suggests a heuristic algorithm to obtain optimal solution of minimum number of aircraft delay in multi-airport arrivals/departures problem. This single airport arrivals/departures problem can be solved by mathematical optimization method only. The linear programming or genetic algorithm that is a kind of metaheuristic method is used for a multi-airport arrivals/departures problem. Firstly, the proposed algorithm selects the median minimum delays capacity in various arrivals/departures capacities at an airport for the number of aircraft in $i^{th}$ time interval (15 minutes) at each airport. Next, we suggest reallocate method for arrival aircraft between airports. This algorithm better result of the number of delayed aircraft then genetic algorithm.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.359-362
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• 2006

This study develops an automatic berthing control algorithm for ships with a bow thruster and a stern thruster as well as a rudder. A nonlinear mathematical model for low speed maneuvering of ships is used to develop a MIMO(multi-input multi-output) nonlinear control algorithm. The algorithm consists of two parts, which are forward velocity control and heading angle control. The control algorithm is designed based on the longitudinal and yaw dynamic models of ships. The desired heading angle is obtained by the so called "Line of Sight" method. An optimal control force allocation method of the rudder and the thrusters is suggested. The nonlinear control algorithms are tested by numerical simulations using MATLAB, and shows good tracking performances.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.124-131
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• 1989

This paper showed that the system reliability optimization problem with sereval failure modes at each subsystem can be treated as efficient computational algorithm proposed here. This algorithm was developed by considering a generalized upper bounding which always exists in constraints when the system reliability optimization problem may be reformulated as 0-1 integer programming problem. We demonstrated the optimal allocation of redundant units for system reliability by using the proposed algorithm. Our algorithm is superior to others in terms of number of iterations and variables used.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.95-96
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• 2008

사회가 발전함에 따라 전력 수요는 기하급수적으로 증가한다. 늘어나는 전력 수요는 전압안정도 마진을 감소시키고 이는 대정전의 원인이 될 수도 있기 때문에 전력계통에서 전압유지 및 전압안정도 여유확보는 중요한 이슈가 된다. 무효전력은 전압과 큰 관련이 있기 때문에 전압유지 및 전압안정도 여유확보 방안으로써 가장 최우선적으로 고려되는 사항이 조상설비를 추가하는 것이다. 하지만 조상설비를 추가하기 위한 용지확보, 비용, 환경문제 등의 영향으로 인한 전원의 원격화, 편재화 그리고 부하의 수요집중화에 의한 송전설비의 장거리화와 대용량화가 진행되고 있으며 이와 같은 장거리 송전에 따라 계통손실의 증가와 수요지의 저전압문제가 발생하고 있다. 그러므로 전압안정도 마진을 고려하면서 조상설비를 적절하게 투입하는 것은 중요한 고려사항이다. 본 논문은 2007년 8월 EMS Peak 데이터를 시뮬레이션 해 조상설비를 투입함에 있어 최적의 위치와 용량을 산정하는 위한 방안을 제시한다. 이러한 조상설비 추가를 최소로 하는 경제적인 측면 뿐 아니라 전압 안정성 측면도 고려하기 위한 부하 scaling 기법을 적용해 전압안정도 여유를 확보하기 위한 방안을 추가한다. 또한 여러 가지 상정사고를 가정한 후 heuristic method를 적용해 조상설비 최적화를 수행하고 한전데이터를 근거로 추가할 조상설비의 가장 적절한 투입위치 및 용량을 산정해 제시한다.

• IE interfaces
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• v.18 no.3
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• pp.317-326
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• 2005

Staff scheduling is an important area, both from an academic and industrial point of view. It has become increasingly important as business becomes more service oriented and cost conscious in a global environment. There has been a lot of study to develop new and efficient staff scheduling models and methods. The purpose of this paper is not to develop new theoretical results but to develop a comprehensive user-friendly staffing model that can be applied to the real-world practice. The developed staffing software, OptStaff, provides the optimal configuration of the customer support center including the selection of customer support center locations, the allocation of staffs to each selected location, and schedules of staffs, so as to minimize the total cost while maximizing the customer satisfaction level. OptStaff also has capability to do scenario analysis by varying the levels of parameters and to create a variety of graphs and reports with user-friendly interfaces.

• Journal of Distribution Science
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• v.15 no.9
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• pp.85-93
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• 2017

Purpose - The volume and valence of online word-of-mouth(eWOM) have become an important part of the retailer's market success for a wide range of products. This study aims to investigate how the growth of eWOM has generated the product's final financial outcomes in the introductory period influences. Research design, data, and methodology - This study uses weekly box office performance for 117 movies released in the South Korea from July 2015 to June 2016 using Korean Film Council(KOFIC) database. 292,371 posted online review messages were collected from NAVER movie review bulletin board. Using regression analysis, we test whether eWOM incurred during the opening week is valuable to explain the last of box office performance. Three major eWOM metrics were considered after controlling for the major distributional factors. Results - Results support that major eWOM variables play a significant role in box-office outcome prediction. Especially, the growth rate of the positive eWOM volume has a significant effect on the growth potential in sales. Conclusions - The findings highlight that the speed of eWOM growth has an informational value to understand the market reaction to a new product beyond valence and volume. Movie distributors need to take positive online eWOM growth into account to make optimal screen allocation decisions after release.

• Journal of Korea Multimedia Society
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• v.16 no.5
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• pp.601-609
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• 2013

One of the most serious factors constraining the next generation cellular mobile consumer communication systems will be the severe co-channel interference experienced at the cell edge. Such a capacity-degrading impairment combined with the limited available spectrum resource makes it essential to develop more spectrally efficient solutions to enhance the system performance and enrich the mobile user's application services. This paper proposes a unique hybrid method of frequency hopping (FH) and subcarrier-reuse-partitioning that can maximize the system capacity by efficiently utilizing the available spectrum while at the same time reduce the co-channel interference effect. The main feature of the proposed method is that it applies an optimal combination of different frequency reuse factors (FRF) and FH-subcarrier allocation patterns into the partitioned cell regions. From the simulation results, it is shown that the proposed method can achieve the optimum number of subcarrier subsets according to the frequency-reuse distance and results in better performance than the fixed FRF methods, for a given partitioning arrangement. The results are presented in the context of both blocking probability and BER performances. It will also be shown how the proposed scheme is well suited to FH-OFDMA based cellular systems aiming at low co-channel interference performance and optimized number of subcarriers.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.24-32
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• 2006

This paper is to analyze the effectiveness of multistatic sonar network based on detection performance. The multistatic sonar network is a distributed detection system that places a source and multi-receivers apart. So it needs a detection technique that relates to decision rule and optimization of sonar system to improve the detection performance. For this we propose a data fusion procedure using Bayesian decision and optimal sensor arrangement by optimizing a bistatic sonar. Also, to analyze the detection performance effectively, we propose the environmental model that simulates a propagation loss and target strength suitable for multistatic sonar networks in real surroundings. The effectiveness analysis on the multistatic sonar network confirms itself as a promising tool for effective allocation of detection resources in multistatic sonar system.