• Journal of Korean Institute of Industrial Engineers
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• v.42 no.1
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• pp.65-72
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• 2016

Curling is compared to the Chess because of variety and importance of strategies. For winning the Curling game, selecting optimal strategies at decision making points are important. However, there is lack of research on optimal strategies for Curling. 'Aggressive' and 'Conservative' strategies are common strategies of Curling; nevertheless, even those two strategies have never been studied before. In this study, Markov Decision Process would be applied for Curling strategy analysis. Those two strategies are defined as actions of Markov Decision Process. By solving the model, the optimal strategy could be found at any in-game states.

• Journal of applied mathematics & informatics
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• v.40 no.5_6
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• pp.857-871
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• 2022

In this work, we formulated a mathematical model for divorce in marriage and extended in to an optimal control model. Firstly, we qualitatively established the model positivity and boundedness. Also we saw sensitivity analysis of the model and identified the positive and negative indices parameters. An optimal control model were developed by incorporating three time dependent control strategies (couple relationship education, reducing getting married too young & consulting separators to renew their marriage) on the deterministic model. The Pontryagin's maximum principle were used for the derivation of necessary conditions of the optimal control problem. Finally, with Newton's forward and backward sweep method numerical simulation were performed on optimality system by considering four integrated strategies. So that we reached to a result that using all three strategies simultaneously (the strategy D) is an optimal control in order to effectively control marriage divorce over a specified period of time. From this we conclude that, policymakers and stakeholders should use the indicated control strategy at a time in order to fight against Divorce in a population.

• Journal of applied mathematics & informatics
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• v.15 no.1_2
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• pp.109-126
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• 2004

This paper deals with two problems of optimal portfolio strategies in continuous time. The first one studies the optimal behavior of a firm who is forced to withdraw funds continuously at a fixed rate per unit time. The second one considers a firm that is faced with an uncontrollable stochastic cash flow, or random risk process. We assume the firm's income can be obtained only from the investment in two assets: a risky asset (e.g., stock) and a riskless asset (e.g., bond). Therefore, the firm's wealth follows a stochastic process. When the wealth is lower than certain legal level, the firm goes bankrupt. Thus how to invest is the fundamental problem of the firm in order to avoid bankruptcy. Under the case of different lending and borrowing rates, we obtain the optimal portfolio strategies for some reasonable objective functions that are the piecewise linear functions of the firm's current wealth and present some interesting proofs for the conclusions. The optimal policies are easy to be operated for any relevant investor.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.410-425
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• 1997

Buildings are mostly under part load conditions causing an inefficient system operation in terms of energy consumption. It is critical to operate building air-conditioning system with a scientific or optimal manner which minimizes energy consumption and maintains thermal comfort by matching building sensible and latent loads. Little research has been performed in developing general methodologies for the optimal operation of air-conditioning system. Based on this research motivation, system simulation program was developed by adopting various equipment operating strategies which are energy efficient especially for humidity control in summer. A numerical optimization technique was utilized to search optimal solution for multi-independent variables and then linked to the developed system simulation model within a mam program. The main goal of the study is to provide a systematic framework and guideline for the optimal operation of air-conditioning system focusing on air-side. For given cooling loads and ambient outdoor conditions the optimal operating strategies of a commercial building are determined by minimizing a constrained objective function by a nonlinear programming technique. Desired space setpoint conditions were found through evaluating the trade-offs between comfort and system power consumption. The results show that supply airflow rate and compressor fraction play main roles in the optimization process. It was found that variable setpoint optimization technique could produce lower indoor humidity level demanding less power consumption which will be benefits for building applications of humidity problem.

• ETRI Journal
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• v.30 no.1
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• pp.81-88
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• 2008

The security threat posed by worms has steadily increased in recent years. This paper discusses the application of the optimal and sub-optimal Internet worm control via Pontryagin's maximum principle. To this end, a control variable representing the optimal treatment strategy for infectious hosts is introduced into the two-factor worm model. The numerical optimal control laws are implemented by the multiple shooting method and the sub-optimal solution is computed using genetic algorithms. Simulation results demonstrate the effectiveness of the proposed optimal and sub-optimal strategies. It also provides a theoretical interpretation of the practical experience that the maximum implementation of treatment in the early stage is critically important in controlling outbreaks of Internet worms. Furthermore, our results show that the proposed sub-optimal control can lead to performance close to the optimal control, but with much simpler strategies for long periods of time in practical use.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1045-1051
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• 2016

This paper introduces a new optimal design method using a bacterial survival strategies for a ectromagnet of Maglev transportation vehicle. Usually, an electromagnetic suspension which has more advantages than electro dynamic suspension is used in Maglev systems. However, the structural constraints must be considered in the optimal design of an electromagnet for electromagnetic suspend system. In this paper, the optimal design method of a electromagnet based on a bacterial survival strategies optimization algorithm to design the electromagnet satisfying the structural constraints. The effectiveness of the proposed method was verified by Matlab simulations and the simulation results show that the proposed method is more efficient than conventional methods.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.2
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• pp.67-73
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• 2012

This paper proposes optimal maintenance strategies for power distribution systems that involve the use of the reliability-centered maintenance (RCM) method. We developed an improved decision model based on the Markov process. This model can obtain the optimal inspection interval and maintenance method based on the total expected cost. We used ordinal optimization for solving the optimal problem. Optimal maintenance strategies were presented by applying the developed method to the RBTS model. A B/C analysis proved that these strategies offer maximum benefit-to-cost.

• Architectural research
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• v.12 no.2
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• pp.9-14
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• 2010

This paper introduces an experimental design studio that explores the optimal use of current digital technologies in order to employ Building Information Modeling at the early phase of design process. Based upon the outcomes from the aforementioned studio, the paper discusses the integrated design strategies for BIM in the design process. In this paper, BIM is proposed as a design tool that increases an overal design productivity more effectively and efficiently compared to BIM as a construction tool with encouraging a design communication among different partakers in the design process.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.271-274
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• 1997

This paper presents the optimization technique for design of a CMAC network by using an evolution strategies(ES). The proposed technique is designed to find the optimal parameters of a CMAC network, which can minimize the learning error between the desired output and the CMAC network's as well as the number of memory used in the CMAC network. Computer simulations demonstrate the effectiveness of the proposed design method.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.254-257
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• 2012

Hedge funds can be established in Korea after the deregulation about setting up private equity funds on September, 2011. Although the variety of asset allocation strategies is the strength of hedge funds, most of Korean hedge funds uses only the equity long/short strategy. Therefore, it is need to introduce other strategies into Korea hedge funds, however all strategies can not be adopted at once because of the infrastructure of Korea financial market. In this paper, we find the optimal introductive order of strategies for Korea hedge fund in view of individual or institutional investors. For this analysis, HFRI data are used for the historical return of each hedge fund strategy and three methods (network visualization, principle component analysis and efficient frontier optimization) are used for finding the optimal order.