• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.842-849
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• 2022

With the development of deep learning technology, there are many cases of using DNNs in embedded systems such as unmanned vehicles, drones, and robotics. Typically, in the case of an autonomous driving system, it is crucial to run several DNNs which have high accuracy results and large computation amount at the same time. However, running multiple DNNs simultaneously in an embedded system with relatively low performance increases the time required for the inference. This phenomenon may cause a problem of performing an abnormal function because the operation according to the inference result is not performed in time. To solve this problem, the solution proposed in this paper first reduces the computation by applying the Tucker decomposition to DNN models with big computation amount, and then, make DNN models run in parallel as much as possible in the unit of hidden layer inside the GPU. The experimental result shows that the DNN inference time decreases by up to 75.6% compared to the case before applying the proposed technique.

• Journal of Power System Engineering
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• v.21 no.3
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• pp.60-65
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• 2017

A GA is one of the best method to find optimal value in searching area. A GA is driven by probabilistic selection that based on the survival of the fittest. So this algorithm need a huge solving time even if it can be used lots of optimizing problem such as structural design, machine learning, system's identification and so on. This GA's characteristic constrain the program to drive offline. Some studies try to use this algorithm on online or reduce the GA's running time with parallel GA or micro GA. Unfortunately these studies still didn't reduce amount of fitness solving. If the chromosome was imported to the system, it affected system's stability. And when the control system uses online GA, it also doesn't have enough learning time. In this study, try to find stability criterion to reduce the chromosome's affection and find the characteristic of the number of population and generation when GA was driven into the wide searching area.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.214-215
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• 2011

2대의 교류발전기 G1과 G2가 병렬운전 중 일 때 내부 기전력 E1, E2는 같은 위상이지만, 크기가 E1>E2로 될 때 두 발전기 사이에는 전위차가 있으므로 횡류 Ic가 흐르게 된다. 남강수력발전소는 주변압기(15MVA, 3.45/66kV) 한대에 수차발전기(7MVA) 2대가 병렬로 운전 중인데, 남강수력 제1호 수차발전기 AVR 시스템의 고장(RS 1기판)으로 G1 발전기의 내부 유기전압과 G2 발전기의 내부 유기전압에 차가 생기고, 이 양자의 차 전압을 전원으로 하여 발전기 G1과 G2를 환류하는 전류가 발생하여 발전 기동 중 비상정지 하였다. 본 논문에서는 고장원인 분석과정 및 AVR 시스템 보수 전 후 파형 비교 및 사고원인을 논하고자 한다.

• Korean Institute of Interior Design Journal
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• v.25 no.6
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• pp.79-88
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• 2016

The purpose of this study was to suggest ways to vitalize residential container architecture by identifying the building process of domestic residential container architecture and analyzing various problems appeared in the process and status of construction related to planning, design, and construction. Conclusion and suggestions of this study are as follows.; firstly, according to the current situation of domestic residential container architecture, the usage was planned mainly for accommodation. Secondly, For planning background of planning preparation stage, economic benefit for long-term residence individuality and diversity for long short term complex residence were the primary planning backgrounds. Thirdly, for floor planning of planning design stage, space planning for various purposes is necessary as creating inter-space, wide LDK space, and loft by using narrow and long container for the long-term residence. Lastly, For construction stage, ways to reduce personnel expenses are being required by reducing the term of works and simplifying the processing stage by running factory production and field construction in parallel. If reduction method of construction cost through energy saving and mass production system is considered in the future, it would be possible to expand the development to dormitory and community housing for university students who are pressured by housing cost.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.397-403
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• 2009

In this paper, an exciter current control of a synchronous generator for ships using a compound type digital automatic voltage regulator (DVAR) in order to provide a constant output voltage of the generator is presented. The compound type DAVR is composed of a controller part to adjust output voltage and an power source unit to supply power to the exciter. The controller part, which generates the PWM switching pattern via the PI controller, drives a power MOSFET for bypass to limit the SG's exciter current. The power source unit part is parallel connected to an output terminal of the generator through a reactor and a power CT. The residual magnetic flux of SG provides exciter current to the exciter through the reactor during the initial running or no load state and load current supplies field current to the exciter through the power CT during loading state. This paper confirmed an experiment to verify the validity of compound type DAVR system for controlling output voltage of synchronous generator.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2729-2731
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• 2005

In present, most of metallic structures(gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in seoul. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential due to stray current of subway system. In this paper, results of development about Real-time Wireless Remote Monitoring System for Stray Current of Subway System are presented.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2732-2734
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• 2005

In present, most of metallic structures(gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in seoul. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential due to stray current of subway system. So, we have developed the Real-time Wireless Remote Monitoring System for Stray Current of Subway System. In this system, the permanent buried type reference electrode is necessary. In this paper, results of development about the permanent buried type reference electrode($Cu/CuSO_4$) are presented.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.805-815
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• 1994

The development of automatic production systems has a trend toward Computer Integrated Manufacturing System(CIMS) in recent years. In hardware configuration, CIMS are composed of intelligent CAD/CAM work stations, multifunction CNC machining centers including material handling systems. The DNC systems present the key element of automation hierarchy in a FMS. A DNC system is one which connects a number of numerically-controlled machines to a common memory in a digital computer for part program storage with provision for on-demand distribution of part program data to machines using communication in hierarchical structure of central computer, control computer and cell controller. This paper describes the development of Behind-the-Tape-Reader(BTR) type DNC system using CYBER 180-830 as a central computer and IBM PC-386 cell control computer and NC lathe with FANUC 5T NC controller. In this system, the connection between central computer and cell control computer is done via RS-232C serial interface board, and the connection between cell control computer and FANUC 5T controller is done via parallel interface board. The software consists of two module, central computer communication module for NC program downloading and status uploading, NC machine running module for NC operating.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.145-147
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• 2005

In present, most of metallic structures(gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in seoul. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential due to stray current of subway system. So, we have developed the Real-time Wireless Remote Monitoring System for Stray Current of Subway System. In this system, the permanent buried type reference electrode is necessary. In this paper, results of development of buried type reference electrode using porous ceramic$({\alpha}-Al_{2}O_{3})$ are presented.

• New & Renewable Energy
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• v.1 no.4 s.4
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• pp.30-37
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• 2005

Cycle simulation of Ground Source Heat Pump[GSHP] system was carried out to determine the design specification of basic components such as turbo compressor and heat exchangers. Part load operation characteristics of the designed GSHP system was estimated using the compressor and heat exchanger performance data. A 50RT class turbo compressor for GSHP system is now under development, in which R134a refrigerant is adopted as working fluid. The compressor with variable cascade diffusers is designed to work both in cooling and heating modes so that it can actively keep up with the climate change with high efficiency. The normal running speeds of the compressor are 59000rpm for heating mode and 70000rpm for tooling mode respectively. It has two identical impellers at both ends of the rotor so as to minimize aero-induced thrust force effectively. GSHP system was coupled with a vortical type heat exchanger, and heat gain and heat loss from ground were evaluated per a bore hole. For the optimal integration of the heat pump system, its header for circulating fluid was combined with the ground heat exchangers in parallel and series configuration.