• 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.

• 전기학회논문지
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• 제65권6호
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• pp.969-978
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• 2016

Around the world are increasing the demand for ESS. Currently, the domestic is expected to benefit by operating ESS. In the domestic, it is expected to benefit from operations of the installed ESS because of the introduction of ESS less capacity. However ESS capacity to the maximum profit occurs is unknown. ESS is different from the charge-discharge characteristics and the reserve to replace, depending on the application. Therefore, it should be established in accordance with the ESS optimal capacity according to the purpose used because it can maximize the quality and efficiency of the electric energy. To the ESS optimal capacity estimation by the purpose used, It should compare the investment cost caused by ESS facility installation and operation cost caused by operating ESS. In this paper, the operation mathematical model for estimating marginal operation costs established. In operation mathematical model, operating cost is considered fuel cost and no-load cost start-up cost. Because no-load cost and start-up cost are not related to cost and power plant output, there are expressed an integer variable costs as a step function.

• 품질경영학회지
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• 제36권1호
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• pp.40-48
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• 2008

The purpose of this study is to rationally manage service facilities of convention center. This study is to develop the algorithm to consider optimal assignment and optimal operation system planning for convention center. The scheduling algorithm of this study develops through constructing the mathematical model and analyzing the mathematical structure of variables and constraints in model. The scheduling algorithm develops to consist eight stage of optimal operation planning and five stage of optimal assignment planning. Especially, this study indicates that optimum answer through mathematical model and results of algorithm is nondiscrimination.

• 전기학회논문지
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• 제62권10호
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• pp.1451-1457
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• 2013

Recently, new concept of energy systems such as microgrid, smart grid, supergrid, and energy network has been introducing. In this paper, the concept of the centralized micro-energy network, which is an energy community of a building group without district heating system, is introduced. In addition, a mathematical model for optimal operation of the micro-energy network as a main function of an energy management system (EMS) for the micro-energy network is proposed. In order to show the validation, the proposed model is tested through the simulation and analyzed.

• 경영과학
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• 제12권1호
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• pp.1-17
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• 1995

The success of cell manufacturing applications in FMS rests on the effective cell formation to maintain the independent relations both between machine cells and between part families. This paper presents an integrated method for concurrent formation of cells and families with no E.E (Exceptional Element) in FMS with alternative routings. To determine the maximum number of cell and family with no E.E, mathematical conditions and properties are derived. New concept of nonsimilarity is introduced for each machine and part based on machine-operation incidence matrix and part-operation incidence matrix. To concurrently form the cells and families, integer programming based mathematical models are developed. For the predetermined number of cell or family, model I is used to identify whether E.E exists or not. Model II forms cells and families considering only nonsimilarity. But model III can consider nonsimilarity and processing times. The proposed method is tested and proved by using numerical examples.

• 대한전기학회논문지
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• 제38권9호
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• pp.724-732
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• 1989

The structure of engine and its interaction are investigated and the construction of mathematical model for the performance evaluation is presented and then simulated. The total system is classified as air-fuel inlet element, intake manifold, combustion, and engine dynamics and their control function are schematically evaluated. Because of the model structure with general engine function and computer simulation of the chosen engine, physical characteristics of the corresponding engine and the engine data of normal operation state are used. According to the study, it is possible to predict the mixture rate by by the difference in the mass of fuel and air into cylinder and to evaluate and trace dynamic characteristic of operation state under various operating condition. The model characteristic under the transient operating condition makes it possible to effectively evaluate the operation of actual engine through the result of simulation.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제15권1호
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• pp.31-40
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• 2012

본 연구는 영재 교수 학습 과정에서 초동영재학생들에게 자기주도적 발견식 탐구식 학습을 실시하여 학습의 효과를 높이고, 수학적 원리와 수학의 심미성을 갖는 창의적인 산출물을 생산해 낼 수 있는 교수 학습 모형을 개발하고, 개발한 모형으로 수업을 진행한 후 나타난 특징에 대하여 탐구하였다. 그 결과 다음과 같은 결론을 얻었다. 첫째, 개발된 영재 교수 학습 모형은 초등수학 영재학생들에게 자료를 통찰하는 능력과 분석적 연역적 추론 능력과 같은 수학적 창의성을 발현하게 한다. 둘째, GSP를 활용한 원형 디자인은 초등수학 영재학생들에게 수학적 패턴을 시각적으로 표현함으로써 추상화된 규칙을 인식하는데 도움을 준다. 셋째, 자연수의 연산을 활용한 원형 디자인은 초등수학 영재학생들의 수학에 대한 심미성과 창의성을 발현하는데 긍정적인 영향을 준다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제19권4호
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• pp.313-327
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• 2016

본 논문에서는 초등학교 영재 학생들의 수학적 창의성 신장을 위한 수 연산 게임과 수업 시안을 개발하고 이를 적용하여 영재 학생들의 수학적 창의성에 미치는 영향을 알아보았다. 창의적 문제 해결학습 모형을 토대로 기존의 게임을 활용하여 10차시의 수 연산 게임 프로그램을 개발하여 학생들에게 적용한 후 학생들의 수학적 창의성 변화를 알아보고자 영재학급 학생 20명을 상대로 검사지를 통한 단일-집단 사전-사후 검사 설계를 적용하였다. Leikin의 평가 준거와 수학적 창의성 측정 방안을 적용하여 얻은 결과, 영재학생들의 수학적 창의성이 신장되었음을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.89-93
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• 1989

In this paper, a mathematical engine model based on the actual engine operation is formulated to be adapted for the evalution and development of engine control system. In the model the classification of fuel paticle siza is considered. The model is simulated through the mathematical interpretation of intake manifold in the rapidly-accerated state. The spark-timing is analyzed with respect to engine r.p.m. The result shows that the model behaves similar performance to the actual engine operation and the spark-timing is very important to the characterization of engine r.p.m..

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.122-128
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• 2020

This research investigates how a Virtual Reality (VR)-based simulation could be used to train safe operation skills for forklift operators. Forklift operation is categorized as high-risk work by many occupational health and safety regulators and authorities due to high injury and fatality rates involved with forklifts. Therefore, many safety guidelines have been developed for forklift operators. Typically, forklift operation safety training is delivered based on instructional texts or videos, which have limitations in influencing people's safety behavior. Against this background, we propose a VR-based forklift simulator that can enable safe operation skills training through a feedback system. The training program consists of several modules to teach how to perform the basic tasks of forklift operation, such as driving, loading and unloading, following the safety guidelines. The system provides instantaneous instructions and feedback regarding safe operation. This training system is based on the model of "learning-by-doing". The user can repeat the training modules as many times as necessary before being able to perform the given task without violating any safety guidelines. The last training module tests the user's acquisition of all safety skills required. The user feedback from several demonstration sessions showed the potential usefulness of the proposed training system.