• Journal of IKEEE
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• v.25 no.2
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• pp.388-398
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• 2021

This paper proposes a particle swarm optimization (PSO)-based peak shaving scheme using energy storage system (ESS) for electricity tariff reduction. The proposed scheme compares the actual load with the estimated load consumption, calculates the additional output power that the ESS needs to discharge additionally to reduce peak load, and adds the input. In addition, in order to compensate for the additional power, the process of allocating power to the determined point is performed, and an optimization that minimizes the average of the load expected at the active power allocations using PSO so that the allocated value does not affect the peak load. To investigated the performance of the proposed scheme, case study of small and large load prediction errors was conducted by reflecting actual load data and load prediction algorithm. As a result, when the proposed scheme is performed with the ESS charge and discharge control to reduce electricity tariff, even when the load prediction error is large, the peak load is successfully reduced, and the peak load reduction effect of 17.8% and electricity tariff reduction effect of 6.02% is shown.

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.89-120
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• 2014

The purpose of the study is to suggest a new approach to the terminal operators in order for them to efficiently control their operation cost and support the strategic decision making system and build a performance evaluation process through the systematic cost analysis approach. This study implemented terminal cost analysis based on the traditional cost system, ABC and TDABC and compared the results of each approach. Throughout the study, the usefulness of TDABC was proved in finding operational problems and suggesting countermeasures for improving cost effectiveness and minimizing unused cost.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.669-670
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• 2020

현재 4차 산업이 진행됨으로써 대부분의 사물들이 자율화 기능이 더해지는 시대가 오고 있다. 자율화 기술이 발전됨으로써 모든 사람들은 삶을 살아가면서 스스로 문제를 해결해 나갈수 있으며 기존의 생활속도보다 빨라지는 것을 느낄수 있을 것이다. 그래서 마트에서도 쇼핑을하면서 소비자들이 어떻게 쇼핑을 할 때 현재의 수준보다 쇼핑의 질이 높아 질지 고안해보았다. 본 과제물은 소비자들이 쇼핑을할 때 보다 편리하게 일을 처리할수도록 스마트 기능을 카트와 카운터에 추가하였다. 카트에 디스플레이와 바코드 스캐너를 부착함으로써 검색을 통해 소비자들이 원하는 물품의 가격, 위치등의 정보를 알아 낼 수 있고 현재 카트에 담긴 물품의 총 가격을 알 수 있다. 또한, 쇼핑을 마치고 계산을할 때 계산 대기줄이 길어지는 불편함을 해소하기위해 자동계산 기능이 있다. 쇼핑을 마친 소비자가 카트를 카운터로 끌고가면 카트에 저장되어 있는 쇼핑정보가 카운터의 디스플레이에 표시되고 카트와 카운터의 정보가 일치한다면 소비자가 카트에 요금을 충전해 스스로 계산을 수행할수 있다. 이런 자동화, 스마트 기능들은 소비자들의 편리함과 시간을 단축시킬수 있을 것이다.

• Journal of the Korea Computer Industry Society
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• v.10 no.5
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• pp.213-220
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• 2009

Regression analysis to estimate the fitted models and test hypotheses are basic statistical tools for survey data as well as experimental data. Data is collected as pairs of independent and dependent variables, and statistics are computed using matrix calculation. To estimate a best fitted model is a key to maximize reliability of regression analysis. To fit a regression model, plot data on XY axis and select the most fitted models. Researchers estimate the best model and test hypothesis with MS Excel's graph menu and matrix computation functions. In this study, I develop macros to estimate the fitted regression model and test hypotheses of relationship between variables. Subway electric charges data with one dependent variable and three independent variables are tested using developed macros, and compared with the results using built-in Excel of regression analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.932-938
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• 2017

This paper presents the structure of an energy management system for distributed energy resources of a grid-connected microgrid. The energy management system of a grid-connected microgrid collects information of the microgrid such as the status of distributed energy resources and the time varying pricing plan through various protocols. The energy management system performs forecasting and optimization based on the collected information. It derives the operation schedule of distributed energy resources to reduce the microgrid electricity bill. In order to achieve optimal operation, the energy management system should include an optimal scheduling algorithm and a protocol that transfers the derived schedule to distributed energy resources. The energy management system operates as a rolling horizon controller in order to reduce the effect of a prediction error. Derived control schedules are transmitted to the distributed energy resources in real time through the international standard communication protocol.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.127-133
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• 2019

A callable product is one of service derivatives using options to generate demand and reduce risk. This paper compares two booking admission controls for callable products, the online and the batch admission controls. To this end, the paper computes the optimal booking policy by using the backward dynamic programming and the stochastic optimization method. Intuitively, the provider should outperform under the batch control by utilizing demand information. The contribution of the paper is to show that the two controls are equivalent in terms of the booking strategy and the expected profit, which enables the provider to keep its current control method. The paper develops the closed-form solutions for the three fare classes. The future work is to extend the result to the model with complicated fare structures.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.633-636
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• 2003

이동망 착신접속료는 독점서비스로 원가인하유인이 없으며 기존의 접속료 산정방식인 완전배부방식의 비합리적이고 부당한 원가계산이 문제점으로 거론되면서 합리적인 요금산정방식은 장기증분원가방식이라고 판단됨으로써 영국에서는 이에 대한 연구가 활발하다. 영국의 장기중분방식은 비용을 회수하는 수단으로 경제적 감가상각을 사용하고 있다. 본 고에서는 기존의 완전배부방식에서 사용되던 회계적 감가상각(역사적 원가와 현행원가방식)과 장기증분원가 방식의 경제적 감가상각 방법을 비교함으로써 감가상각 방법에 따라 이동망 착신접속료에 미치는 영향 및 시사점을 분석해 보고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.343-344
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• 2015

본 논문에서는 무선 센서 네트워크 기반의 전력 소모 측정 데이터를 모바일 기기로 제공하는 전력 검침 시스템을 제안한다. 디지털 전력량계의 전력 소모 측정데이터를 전송하는 아두이노 보드와 전송된 정보를 수신하는 게이트웨이 및 수집된 전력량을 환산하는 서버와 소비전력을 스마트폰에 모니터링하는 앱으로 구성된다. 전력미터기는 Zigbee를 이용한 Sensor Network를 구성하여 전력데이터를 전송하며 아두이노 보드를 통해 서버에서 소모전력량과 요금을 계산하고, 무선 LAN을 통해 서버에 접속한 모바일 단말기에 전력사용량을 실시간으로 알 수 있도록 한다. 이러한 전력 검침 시스템을 구현하여 실시간으로 집안의 소모전력을 모니터링할 수 있으며 전력절감을 유도하는 것을 목적으로 한다.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.111-120
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• 2004

This paper presents an application of Unified Modeling Language(UML) software technique for developing transmission pricing evaluation package. Also, this paper describes a transmission pricing algorithm applicable to a large-scale power system. The usage-based transmission pricing mechanism is very complex since it requires power flow analysis, fault current analysis, sensitivity evaluation of a transmission line, penalty factors calculation, transmission asset databases, and cost allocation rules, etc. For the efficient and flexible development of the transmission pricing package, a UML. approach is applied, which is composed of a use-case diagram, interaction diagram, class diagram, and package diagram using Rational Rose Unified Process(RUP). The designed transmission pricing package can be efficiently modified and reused as the market environments evolves since it is designed by Object-Oriented Programming(OOP).

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.422-424
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• 2002

Many methods about real power flow tracing have been suggested. Electric power industrials and organizations of the world use the method which is best suitable to themselves in practical aspects. In this paper we calculate the real power transfer between individual generators and loads referencing the method introduced by oversea's paper. It is considered to be significant to the wholesale competition market and transmission open access. Based on ac load flow solution and graph theory, the simulation on IEEE 30-bus system are carried out and the results are compared with that of oversea's paper. Also the simulation on the power system of Korea is carried out and the results are analyzed.