• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.847-858
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• 2015

Control strategy and corresponding parameters have significant impacts on the overall technical and economic characteristics of composite energy storage systems (CESS). A better control strategy and optimized control parameters can be used to improve the economic and technical characteristics of CESS, and determine the maximum power and stored energy capacity of CESS. A novel coordinated control strategy is proposed considering the coordination of various energy storage systems in CESS. To describe the degree of coordination, a new index, i.e. state of charge coordinated response margin of supercapacitor energy storage system, is presented. Based on the proposed control strategy and index, an optimization model was formulated to minimize the total equivalent cost in a given period for two purposes. The one is to obtain optimal control parameters of an existing CESS, and the other is to obtain the integrated optimal results of control parameters, maximum power and stored energy capacity for CESS in a given period. Case studies indicate that the developed index, control strategy and optimization model can be extensively applied to optimize the economic and technical characteristics of CESS. In addition, impacts of control parameters are discussed in detail.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.55-61
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• 2009

This paper presents a modified Phasor Discrete Particle Swarm Optimization (PDPSO) algorithm to configure Community Energy Systems(CESs) in the distribution system. The CES obtains electric power from its own Distributed Generations(DGs) and purchases insufficient power from the competitive power market, to supply power for customers contracted with the CES. When there are two or more CESs in a network, the CESs will continue the competitive expansion to reduce the total operation cost. The particles of the proposed PDPSO algorithm have magnitude and phase angle values, and move within a circle area. In the case study, the results by PDPSO algorithm was compared with that by the conventional DPSO algorithm.

• Bulletin of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.30-31
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• 2024

• Fire Protection Technology
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• s.16
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• pp.24-27
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• 1994

This report is relevant to the fire-hazard implied in Access Floor being composed of combusti-ble materials. It emphasizes the importance of component materials and first-phased extinguishment for Ac-cess Floor with respect to fire-prevention.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.85-90
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• 2010

This paper presents a technique to evaluate the reliability of customers in Community Energy System(CES). Operators of the CES are responsible for a reliable energy supply to their customers. Due to the strategy of the priority on their customers, the restoration process of DGs should be reordered when system outage happens. The previous study has proposed the technique in the distribution system in which one operator owns all DGs. Case studies in Bus 2 of Roy Billinton Test System(RBTS) verify that the accuracy of the proposed technique is comparable to that of previous technique, and the distribution system divided into several CESs changes the reliability index of customers in the CESs.

• Journal of applied mathematics & informatics
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• v.7 no.2
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• pp.617-627
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• 2000

ATM networks support diverse traffic types with different service requirement such as data, voice, video and image. This paper analyzes a dynamic priority queue to satisfy Quality of Service (QoS) requirements of traffic. to consider the burstiness of traffic, we assume the arrival to be a Markovian arrival process(MAP) . Performance measures such as loss and delay are derived, Finally, some numerical results show the performance of the system.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.71-77
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• 2019

Purpose: The purpose of this study was to compare the level of muscle activation on the cervical erector spinae (CES), lumbar erector spinae (LES), and upper trapezius (UT) according to the sitting postures while using a smartphone in the bathroom. Method: Thirty-two healthy subjects were recruited for this study. The CES, LES, and UT were evaluated by surface electromyography according to two sitting postures while using a smartphone on the toilet seat. A paired t test was performed for the root mean square of reference voluntary contraction (%RVC) comparisons between two sitting postures, and one-way ANOVA was used to compare the three muscle activations within each posture. Results: A comparison between the two sitting postures revealed the muscle activation of both CESs in sitting posture 2 and both LESs in sitting posture 1 to be significantly higher than those of the others. In sitting posture 1, the muscle activation of both LESs was significantly higher than those of the CES and UT. In sitting posture 2, the muscle activation of both CESs was significantly higher than those of the LES and UT. Conclusion: High muscle activation of the CES and LES was observed according to the sitting postures when using smartphone in the restroom. Therefore, long time use of smartphones on a toilet seat should be avoided.

• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.1002-1005
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• 1998

Bismuth titanate thin films were prepared on {{{{ { SrTiO}_{3 } }}(100) and Si(100) substrates by dipping-pyrolysis pro-cess using metal naphthenates as starting materials. crystallinity and in-phase alignment of the films were analyzed by X-ray diffraction $\theta$-2$\theta$ scans and $\beta$ scans (pole-figures) respectively. Highly c-axis-oriented {{{{ { { {Bi }_{4 }Ti }_{3 }O }_{12 } }} thin films with smooth surfaces were obtained after heat treatment at 75$0^{\circ}C$ on {{{{ { SrTiO}_{3 } }}(100) sub-strate while the films grown of Si(100) exhibited polycrstalline characteristics. C-axis oriented film show-ed an epitaxial relationship with the {{{{ { SrTiO}_{3 } }} substrate.

• Journal of Powder Materials
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• v.11 no.6 s.47
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• pp.522-527
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• 2004

Nano sized FeAl intermetallic particles were successfully synthesized by plasma arc discharge pro-cess. The synthesized powders shouted core-shell structures with the particle size of 10-20 nm. The core was metallic FeAl and shell was composed of amorphous $AI_{2}O_{3}\;and\;a\;little\;amount\;of\;metallic\;Fe_{3}O_{4}.$ Because of the difference of Fe and Al vapor pressure during synthesis, the Al contents in the nanoparticles depended on the Al contents of master alloy.

• Journal of Biomedical Engineering Research
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• v.12 no.1
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• pp.9-18
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• 1991

A micro- computer system has been designed to evaluate the performance of commercial infant incubator and to develope the temperature controller of new incubator. The measure- ment system used a hybrid of analog electronics for amplification, integration, and switches and micro-computer for data storage, data display, and control of relay. This approach has been applied to measure the warm-up time, temperature stability, open/close door and port- holes, and temperature distribution on the mattress. The micro-computer provides on-line ac cess of multi-point temperature data, simplifies the analog part of the circuit and gives the flexibility.