• 충청수학회지
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• 제26권1호
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• pp.85-90
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• 2013

We use the dynamic programming method to investigate the optimal consumption and investment problem with regime-switching. We derive the optimal solutions in closed-form with constant absolute risk aversion (CARA) utility.

• ETRI Journal
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• 제30권1호
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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.

• 대한수의학회지
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• 제31권1호
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• pp.49-53
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• 1991

The present study has been carried out to investigate the optimal condition on lymphocyte blastogenesis of rabbit lymphocytes, whole blood culture and microculture system in conjunction with a semiautomatic multiple sample harvester(SAMSH) was used to study the In vitro optimal condition of rabbit lymphocytes. Data were presented to show many variables that are involved in studying the phytohemagglutinin(PHA) and lipopolysaccharide(LPS) response of rabbit lymphocyte in a microculture system. Analysis indicated that the conditions for optimal PHA as measured by incorporation of $^3H$-TdR include: (1) use of RPMI-1640 as culture medium. (2) use of $6{\mu}g$ of PHA, per culture. (3) 48-hours culture period. Conditions for optimal stimulation with LPS mitogen were similar to those used for PHA.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.2911-2913
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• 1999

This paper suggest an optimal identification method to complex and nonlinear system modeling that is based on Fuzzy-Neural Network(FNN). The FNN modeling implements parameter identification using HCM algorithm and optimal identification algorithm structure combined with two types of optimization theories for nonlinear systems, we use a HCM Clustering Algorithm to find initial parameters of membership function. The parameters such as parameters of membership functions, learning rates and momentum coefficients are adjusted using optimal identification algorithm. The proposed optimal identification algorithm is carried out using both a genetic algorithm and the improved complex method. Also, an aggregate objective function(performance index) with weighted value is proposed to achieve a sound balance between approximation and generalization abilities of the model. To evaluate the performance of the proposed model, we use the time series data for gas furnace, the data of sewage treatment process and traffic route choice process.

• 전기학회논문지
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• 제65권6호
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• pp.979-986
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• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• 설비공학논문집
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• 제16권2호
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• pp.111-120
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• 2004

The optimal design method of indoor thermal environment using CFD coupled simulation and genetic algorithms (GA) is developed in this study. CFD could analyze the thermal environment considering the distribution of temperature, velocity, etc. in a room. Therefore, It would be appropriate to use CFD for the optimal design method considering their distribution. In this paper, the optimal design means the most appropriate boundary conditions of the room among the conditions where the design target of indoor therm environment is achieved. Two step optimal indoor thermal environment design method is proposed. It includes the GA for searching the optimal indoor thermal environment design. To examine the performance of this method, the optimal design of hybrid ventilation system, which uses the natural cross ventilation and the radiation-cooling panel is conducted. The optimal design which satisfies the design target (thermal comfort, minimum cooling load, minimum vertical temperature difference) is found using two step optimal design method.

• 대한교통학회지
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• 제20권4호
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• pp.27-38
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• 2002

교통운영의 효율성과 안전성을 획기적으로 향상시키는 차세대교통체계인 ATIS 하부시스템 중 공공성과 사업성을 동시에 가지는 VTIS는 매우 중요하다. 특히, 특정이용자의 수요에 따라 상세한 교통정보를 제공할 뿐만 아니라, 민간부문의 참여도가 높아 부가적인 파급효과의 기대가 크므로 시급한 도입이 예상된다. 하지만 VTIS 서비스 제공매체는 상당히 다양하기에 각 제공매체별로의 적정요금과 요금지불방식도 상당히 다양해지므로, 이에 대한 적절한 기준이나 연구가 시급한 실정이다. 하지만 기존 연구들은 최적경로 산정에만 치중되어 있어 서비스 이용수요와 이용자의 입장이 고려된 적정이용료 산정에 대한 연구는 전무하다. 따라서 본 연구는 가상의 다른 가격시나리오 하에서 VTIS 서비스의 이용여부를 설문조사하고, 이항로짓모형을 이용하여 운전자들의 이용수요를 예측하였다. 그리고 설문조사시 이용응답자를 대상으로 순서형 프로빗 모형을 이용하여 각 지불방식별로 이용행태 범주별로 이용률을 산정하고 이에 민감도 분석을 실시하여 월별 지불방식에서는 2800원, 통화당 지불방식에서는 한 통화당 145원의 적정이용료를 산정하였으며 이때의 VTIS 서비스 이용률은 각각 65%와 75%로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.240-243
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• 1995

In excavating tunnels, shield tunneling machines having many cutters on their cutter planes are used. Not many observation data being available in the detection system, optimal observation policy is very important. From this viewpoint, we previously considered the optimal location of acoustic sensors on the cutter plane and also the optimal observation policy for the case where three receiving transducers were used, and showed that the optimal sensor location was given as arbitrary equally-spaced points on the cutter plane circle, and that the optimal rotating angles were also found to be arbitrary. In application, however, it is often difficult to locate sensors at arbitrary positions or to use three sensors from the viewpoints of machine structure and cost. This paper considers the optimal observation policy for detecting anomlous plane objects for the case where two receiving transducers are used and the case where three receiving transducers are located only on a diameter of the cutter plane.

• International Journal of Control, Automation, and Systems
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• 제5권4호
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• pp.471-478
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• 2007

In this paper, an optimal Wiener-Hopf decoupling controller formula is obtained which is expressed in terms of rational matrices, thereby readily allowing the use of state-space algorithms. To this end, the characterization formula for the class of all realizable decoupling controller is formulated in terms of rational functions. The class of all stabilizing and decoupling controllers is parametrized via the free diagonal matrices and the optimal decoupling controller is determined from these free matrices.

• 대한수학회지
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• 제34권4호
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• pp.841-857
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• 1997

We present analysis and some computational methods for boundary optimal and feedback control problems for Navier-Stokes equations. We use one example to illustrate our methodology and ideas which are applicable to general control problems for Navier-Stokes equations. First, we discuss the existence of optimal solutions and derive an optimality system of equations from which an optimal solution may be computed. Then we present a gradient type iterative method. Finally, we present some numerical results.