• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3910-3922
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• 2000

Current power systems are distributed geographically and operated in the form of Energy Management System(EMS)/ Supervision Control and Data Acquisition(SCADA) with the aid of computers and communications. Recently a variety of utilities have had interests in using inforrration technology to bring the efficiency and low operational costs. There is also a trend to integrdte the production, transmission, distribution and management/control of power into one and unified distributed system. To this end, Electric Power Hesearch Institute(EPRI) announced a new standard communication protocol called Inter-Control Center Protocol(ICCP).ICCP specifies the use of Manufacturing Message Specification(MMS) for services required by rccr in application layer and supports the communications between heterogeneous control centers. This paper presents the characteristics of MMS,ICCP and their relationship. Futherrnore, we implement the basic functional blocks of ICCP using MMS services under TCI/IP environments. Finally, we model a simple power system and apply the rccp protocol to this system in a window-based scheme, and finally show the operation and validation of this protocol.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.83-93
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• 2007

In this paper, we address a power-aware scheduling algorithm for a mixed real-time system which consists of periodic and sporadic tasks, each of which is characterized by its minimum period, worst-case execution requirement and deadline. We propose a dynamic voltage scaling algorithm called DVSMT(DVS for mixed tasks), which dynamically scales down the supplying voltage(and thus the frequency) using on-line distribution of the borrowed resources when jobs complete while still meeting their deadlines. With this scheme, we could reduce more energy consumption. As the proposed algorithm can be easily incorporated with RTOS(Real-Time Operating System), it is applicable for handhold devices and sensor network nodes that use a limited battery power. Simulation results show that DVSMT saves up 60% more than the existing algorithms both in the periodic-task and mixed-task systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.719-726
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• 2002

In WRC-2000, Resolution 734 was adopted to study the use of high altitude platform station(HAPS) operating in the bands above 30GHz. Therefore, frequency sharing feasibility between a new HAPS systems and an existing terrestrial fixed-service(FS) system should be analyzed primarily. In this paper, interference effects from the HAPS system into the radio-relay station are analyzed in terms of two cases; one is the interference distribution from the power-flux density(PFD) of HAPS airships, and the other the interference power from the ground stations. In conclusion, the new PFD criteria different from the exiting satellite system should be required, and the coordinated distance between the HAPS nadir and the radio-relay station should be 60km ∼ 253km for P$\sub$HG/ = -50dBW/MHz of transmitting power spectral density to share the new HAPS system into the existing FS system.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.464-477
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• 2019

With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.4
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• pp.1123-1146
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• 2023

In South Korea, there have been many studies on efficient building-energy management using renewable energy facilities in single zero-energy houses or buildings. However, such management was limited due to spatial and economic problems. To realize a smart zero-energy city, studying efficient energy integration for the entire city, not just for a single house or building, is necessary. Therefore, this study was conducted in the eco-friendly energy town of Chungbuk Innovation City. Chungbuk successfully realized energy independence by converging new and renewable energy facilities for the first time in South Korea. This study analyzes energy data collected from public buildings in that town every minute for a year. We propose a smart city building-energy management model based on the results that combine various renewable energy sources with grid power. Supervised learning can determine when it is best to sell surplus electricity, or unsupervised learning can be used if there is a particular pattern or rule for energy use. However, it is more appropriate to use reinforcement learning to maximize rewards in an environment with numerous variables that change every moment. Therefore, we propose a power distribution algorithm based on reinforcement learning that considers the sales of Energy Storage System power from surplus renewable energy. Finally, we confirm through economic analysis that a 10% saving is possible from this efficiency.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1869-1871
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• 2004

The primary role of ZnO arresters is to protect transmission and distribution equipments against lightning surges. The extremely nonlinear V-I characteristics of the ZnO arrester obviates the need for isolation gaps and consequently it is continuously connected to line voltage. For this reason, ZnO arresters are degraded with increasing with time in actual power systems. In this work, the characteristics of the luminous events between the ZnO block and electrodes were investigated. As a result, the luminous events were effected by the impulse and the near polarity of the luminous event was intense near the grounded electrode. Also the luminous event may cause the degradation of ZnO arrester block.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.245-246
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• 2013

본 논문에서는 DC배전용 전력변환장치를 모듈화하여 병렬운전을 하기 위한 새로운 Droop 제어를 제안한다. 제안한 방식은 동일용량의 모듈을 병렬로 용이하게 연결할 수 있으며 모듈간 제어진동을 최소화하고 순환전류를 억제한다. 이에 따라 병렬 운전 시스템이 갖는 과도응답 및 정상상태 특성 등을 시뮬레이션과 실험을 토대로 그 타당성을 검증하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.5
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• pp.488-494
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• 2005

The ejector is used to obtain a vacuum state, and it has been applied to a lot of industry field such as a heat engine, a fluid instrument power plant. a food industry, an environment industry etc., because there is no problem even it is mixed with any kind of liquid, gas. and solid. The flow characteristics in the ejector was investigated by a PIV and a CFD. The agreement between numerical analysis and experiment shows the validity of this study and the results of this study would be useful to the engineers who design for the flow systems for heating. ventilation. air conditioning and wastewater purification plants.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.1
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• pp.50-64
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• 2012

Quality of Service (QoS) and fairness considerations are undoubtedly essential parameters that need to be considered in the design of next generation scheduling algorithms. This work presents a novel game theoretic cross-layer design that offers optimal allocation of wireless resources to heterogeneous services in Orthogonal Frequency Division Multiple Access (OFDMA) networks. The method is based on the Axioms of the Symmetric Nash Bargaining Solution (S-NBS) concept used in cooperative game theory that provides Pareto optimality and symmetrically fair resource distribution. The proposed strategies are determined via convex optimization based on a new solution methodology and by the transformation of the subcarrier indexes by means of time-sharing. Simulation comparisons to relevant schemes in the literature show that the proposed design can be successfully employed to typify ideal resource allocation for next-generation broadband wireless systems by providing enhanced performance in terms of queuing delay, fairness provisions, QoS support, and power consumption, as well as a comparable total throughput.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.43-46
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• 2009

This paper describes a development of the temporary transformer system and method. The failure causes are genrally divided into problems in manufacturing, mounting and operating. To replace the bum-out pole transformers developed various facilities, power cable clamp, the control panel of self-sensing device and voltage connection box etc. That is more effective to establish the emergency transmission systems for the non interruption replacement of distribution transformers.