• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.42-48
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• 2005

A DC-DC converter is being widely used for various household appliances and for industry applications. The DC-CC converter is powered from single battery, and the voltage is varied according to the purpose. In the vehicle, various accessories whose electric power is different are being un4 Thus, plural number of DC-DC converter should be provided, so these situations bring complicated circuits, and accordingly, higher cost. Under such backgrounds, in this paper, we propose a novel buck-boost chopper circuit with simply configuration which can supply to two or more different output loads. The propose chewer circuit can control output voltages by controlling duty ratio by using typically two switching devices, which is composed by single boost-switch and single buck-switch. The output voltage can be controlled widely. A few modified circuits developed from the fundamental circuit are represented including the general multi-load circuit. And all this merits and appropriateness was proved by computer simulation and experience.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1881-1886
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• 2016

In this paper, by using D2D communications that perform direct communications among devices within small transmission range of each device without base station, we assume that a device generates and transmits data packets to other proximate devices and the devices which receive the data packets relay those to other adjacent devices. To maximize the total number of devices which successfully receive data packets, Epidemic routing protocol is considered in this paper. In Epidemic routing protocol, all devices which received data packets try to relay the packets to other adjacent devices. We assume various network environment where devices are densely distributed in specific area(crowded area). In this environment, D2D SD can be a source node and D2D devices can be relay nodes. By setting transmission range of D2D SD and D2D devices as parameters, we analyze performance results of coverage probability of Epidemic routing protocol through intensive simulations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1213-1217
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• 2011

Electric stimulators are used for various treatments, such as for pain relief and to improve rehabilitation in and out of the hospital. However, if the stimulation pulse affects the patient's heart, it can cause critical cardiac disorders such as arrhythmia or ventricular fibrillation. As a result, it must be ensured that the transmission length of the stimulation pulse does not exceed the proper range in the design of an electric stimulator. Furthermore, every anticipated risk factor must be monitored in in-vitro and in-vivo experiments. A new stimulator was designed to supply continuous 0.001 J stimulation pulses at a rate of 60 pulses per second. To evaluate the safety of the new electric stimulator and to measure its energy transfer and pulse transmission length, we built a conduction model that was filled with saline and measured the electric field at various positions in response to real stimulations. In an animal experiment with two pigs, heart disorders were induced by applying electric stimulation to tissues near the heart. These heart disorders were different from the result obtained with 9 V DC stimulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1675-1680
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• 2010

Flow Accelerated Corrosion (FAC) occurring during in-service conditions results in localized wall-thinning in the feeder pipes of CANDU. The wall-thinning of the feeder pipes is the main degradation mechanisms affecting the integrity of piping systems. In this paper, we assess the integrity of wall-thinned feeder pipes by limit load analysis. The limit loads for wall-thinning feeder pipes subjected to in-plane bending and internal pressure were determined on the basis of finte element limit analyses. The limit loads are determined from the results of limit analyses of elasticperfectly-plastic materials using the large geometry change. Closed-form approximations of limit load solutions for wall-thinning feeder pipes subjected to in-plane bending and pressure are proposed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1123-1130
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• 2008

Baby's diseases diagnosis has inconvenient for received direct coming to help that order expression ability was insufficiency which consciousness situation concern about the infant health because of birth rate and decrease the marriage rate and divorce rate. So in this paper through the infant crying sound about home a foundation which infant diseases develop the system comparison normal infant with take a infant that analysis the extract the voice analytics component. Especially this paper propose about the methodology for development system that infant cold, infant pneumonia, infant asthma among extract the crying sound feature part for infant respiratory diseases discussion the most easy has involved the infant. So infant respiratory put case stimulus diseases about all voice organs and experiment the analysis method through the bandwidth about phonetics analysis component that comparison normal infant with take a respiratory infant. Through these method, we were extracted to results that infant's frequency bandwidth suffering from respiratory diseases than a normal infant is short.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.479-482
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• 2011

This paper proposes a design of a ship backbone network-based on the survival and efficiency of the ship network. Currently IEC operates the standard ship network, a standard specification "IEC 61162-410 maintains the operation of the network. IEC 61162-410 offers a high stability of the ship network by using terminal equipment. But current studies are incomplete because it has been assumed that the ship's network will operate at double its current capacity. This paper analyzes the double ship backbone topology for an organization and then will summarise the minimum costs required to implement the ship backbone topology using an ILP. Also, we present an effective traffic assignment technique that uses an ILP, metaheuristic, heuristic algorism-based underlying the ship backbone network. The results by experimenting the design of the network confirmed a greter efficiency, stability and cost-effectiveness of the ship network.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.741-744
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• 2004

디지털 홈 시대의 도약으로 가정용 TV의 기능과 그 역할이 확대되면서 Digital TV(DTV)가 새로운 가전기기의 하나로 등장하게 되었다. DTV를 통한 디지털 데이터 방송뿐 아니라 웹 컨텐츠의 다양한 활용이 가능하게 되면서 기존의 PC 환경과는 다른 DTV 환경에 적합한 새로운 컨텐츠 표현 규격이 필요해졌다. 이에 다수의 디지털 데이터 방송 표준 단체들이 DTV를 위한 디지털 데이터 방송용 컨텐츠 표현 규격을 제시하고 있고, DTV가 등장하기 이전부터 TV와 웹의 접목 기술을 위한 W3C의 활동도 있어왔다. 또한 양방향 TV 서비스 또는 웹 TV 서비스를 제공하는 방법으로 자체적인 컨텐츠 표현 규격을 정의하고 브라우저 등의 프로그램을 통해서 시청자들에게 TV에 특화된 다양한 웹 컨텐츠를 제공하고 있다. 이에 본 논문에서는 현재까지 제시되어 온 DTV 또는 TV환경을 위한 컨텐츠 표현 규격들을 다양한 관점에서 비교 검토해보고자 한다. 또한 DTV가 가지는 특징들을 살펴봄으로써 TV와 다르고 또한 PC와도 다른 DTV만의 특성을 반영할 수 있는 컨텐츠 표현 방법을 제시하고자 한다. 이를 통해서 DTV 시장 활성화의 선두 위치에 있는 국내에서 DTV 용 컨텐츠의 표현 규격에 대한 보완 및 발전 방향을 숙고하고, 세계적으로도 앞서가는 인터넷 서비스 시장이 DTV를 통해서 안방에서 보다 효율적이고 간편한 방법으로 다양한 계층의 사용자에게로 확대될 수 있는 계기를 마련하고자 한다.

• Journal of Energy Engineering
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• v.22 no.3
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• pp.307-311
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• 2013

Heating and hot water has accounted for 68% of Korea's household energy usage. Boiler makes up the bulk of the heating and hot water production. Hence a highly efficient boiler is needed in order to reduce energy consumption. A condensing boiler that recovers latent heat is known to be highly efficient. However, it is expensive and takes more space to necessitate research for improvement. In the present study, we investigated condensation heat transfer of a surface roughened by etching treatment. The etched plate showed 9.2% increase in heat transfer compared to original plate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1904-1910
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• 2011

At most of the home or office, we have planted ornamental plants raised in pots, but it is difficult to follow because of busy life and lack of expertise in plants management. In this paper, we intend to design and implement a home network-based potted plants management system to solve the difficulty of plants management. To attain this end, firstly, we designed the structure of the plants management system, information flows and operation control flows. Secondly, we implemented the system based on designed results. Finally, we verified the implemented system through the functionality test for 10 items. In the results, it is expected that we can manage the potted plants efficiently than existing ornamental plant management systems and home network systems focusing appliances.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.28-33
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• 2015

In this study, a dual fuel engine fueled with natural gas and diesel was tested to investigate the effects of heating value variation of CNG fuel. CNG substitution rate which is defined as the ratio of CNG and diesel supplied in a heating value basis was fixed at 80%. The higher heating value was varied from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$ by mixing nitrogen gas with pure CNG and diesel fuel was injected at a fixed injection timing. The engine test results showed that thermal efficiency and power output were decreased as the heating value of mixed CNG fuel was decreased. And the peak cylinder pressure was also decreased but the ignition delay time and the combustion duration and timing were almost same.