• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.191-198
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• 2011

According to the propagation of fuel cell system, the importance of that system efficiency is being magnified. Thus, the efficiency improvement of reformer which is the important factor of fuel cell system will be required. This study has been experimentally performed to evaluated the performance of plate type STR reactor. At first, we changed fuel flow rate (2, 3 and 4 l/min) in burner, and then we measured a proportion of hydrogen in produced gas through the STR reactor by G.C for evaluating the performance of plate type STR reactor in various fuel supply conditions. And we changed S/C ratio (2 and 4) and measured a proportion of hydrogen in produced gas through the STR reactor. As a results, condition at fuel flow rate 2 and 3 l/min could not be supplied amount of heat for STR sufficiently. Condition at fuel flow rate 4 l/min could supplied a heat excessively. And condition at S/C ratio 2, reaction occurred insufficiency. But condition at S/C ratio 4 was excess. From above, we found the optimum conditions that were fuel rate 3.5 l/min and S/C ratio 3.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.1015-1022
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• 2007

In this paper, dual-band digital codec for UHF(Ultra High Frequency) and MW(Micro Wave) is proposed for an RFID reader system. Most RFID systems have been supported only one protocol. But, There are many protocols of each bandwidth. Especially, UHF bandwidth which is widely used on the globe consists of A,B,C type, and more standards will be established. Recently, Since an interest about mobile RFID system is increasing, the RFID system with more than one protocol will be need. Therefore, this paper suggests a dual-band digital codec with UHF and MW bands for an RFID reader system. Standards used in this system are 18000-6C and 18000-4 standards. The digital codec is synthesize by the Quartus II compiler. Target device is EPC20Q240C8 which is family of CycloneII. Main Clock is 19.2MHz and elements of FPGA which is used for the system is 18,752.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.215-222
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• 1993

Malononitrile(MN) as a reactive additive was added to Diglycidyl ether of bisphenol A (DGEBA)/Methylene dianiline (MDA) system in order to modify a thermosetting epoxy resin. Cure ki. netics and cure mechanism of this modified system were investigated by using DSC(differential scanning calorimetry) and FT-IR(fourier transform infrared spectrometry). Cure kinetics gave an information that the DGEBA/MDA system modified with MN should cure at over $110^{\circ}C$ after curing at about $80^{\circ}C$ for the complete curing. The activation energy of the first cure was nearly constant and that of the second cure was increased as the MN content was increased. Cure mechanism for the system was investigated with the samples cured every $30^{\circ}C$, from $80^{\circ}C$ to $170^{\circ}C$, for Ihr. It was known that the cure reactions of the epoxy-diamine system were composed of PA -E, SA - E and E-OH reactions. Beside these three reactions, in the DGEBA/MDA/MN system PA-CN and CN-OH reaction was found.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.227-237
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• 1998

A numerical simulation has been carried out for the automotive air conditioning system. The purpose of this simulation is to present the methods for simulating car air conditioning components, systems and cool-down performance by computerized mathematical model and to analyze the performance of A/C system. In analyzing the heat exchanger(evaporator and condenser), the finite volume model which has a merit in predicting the temperature field in detail because it can consider partial variation of thermal property and heat transfer coefficient is used. In analyzing the compressor, the polytropic approach which regards the actual compression process as a reversible polytropic process is employed. In analyzing vehicle passenger compartment, the thermal network is employed to simulate the car cool down process. This A/C system program can be used for analyzing a component performance when a component is alternated or designed and for analyzing the engine cooling system when A/C system is operated.

• Proceedings of the Acoustical Society of Korea Conference
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• 1991.06a
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• pp.58-63
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• 1991

This paper describes development of small scale voice dialing system using TMS320C30. Recognition vocabuliary is used 50 department name within university. In vocabulary below the middle scale, word unit recognition is more practice than phoneme unit or syllable unit recognition. In this paper, we performend recognition and model generation using DMS(Dynamic Multi-Section) and implemeted voice dialing system using TMS320C30. As a result of recognition, we achieved a 98% recognition rate in condition of section 22 and weight 0.6 and recognition time took 4 seconds.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.2
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• pp.280-288
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• 2003

We need refrigeration system which can maintain the freshness of agricultural products, because of being distance from a tiller to a consumer. Vacuum Pre-cooling system has an advantage in quality maintenance through vapid cooling down by using latent heat of evaporation of stored products. A number or thawing methods in current use have also several disadvantages in thawing time. discoloration mass loss caused by drying, capital costs and running cost. These damages are, it is claimed, either eliminated or improved by the vacuum thawing system. An experimental study on the pre-cooling for the bean sprouts and cabbage, and thawing for hairtail and croaker by the low temperature vacuum system were carried out. The cabbage cooling time with this Pre-cooling vacuum system took about 60 minutes to reach from $23.2^{circ}C to 4.5^{\circ}C$ at 5 mmHg abs. ($6.66\times10^{-4}$ MPa). The croaker thawing time with this low temperature vacuum thawing system took about 170 minutes to reach from $-10.3^{circ}C to -0.8^{\circ}C$ at 20 mmHg abs ($2.67\tiems10^{-3}$MPa). The vacuum Pre-cooling and thawing system have merits compared with present systems in their short intervals to cool down and to thaw without any quality losses.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.129-134
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• 2020

Moisture infiltration inside the solar cell module, filling of EVA sheet, melting of the frame seal, and deterioration of power generation performance in the module one year after installation are occurring. Whitening phenomenon, electrode corrosion phenomenon, and dielectric breakdown phenomenon are appearing in solar cell module installed in Korea before 5-7 years, leading to deterioration of power generation performance, and big problems for long-term reliability and long life technology are emerging. Therefore, in order to solve these problems, the development of a micro inverter (MiCrco Inverter Converter, MiC) including the function of securing the durability of the solar cell module and monitoring the aging progress and the solar cell based on the monitoring data from the MiC smart monitoring programs have been proposed to determine the aging of modules. In addition, in order to become a highly efficient solar smart monitoring system through systematic operation management through IT convergence with MiC that has enhanced monitoring function of solar cell module, SoC(System On Chip) in micro inverter is the environment for solar cell module. There is a demand for functions that can detect information in a complex manner and perform communication and control when necessary. Based on these requirements, this paper aims to develop SoC-based low-cost MiC smart photovoltaic system technology.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2216-2217
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• 2008

This paper write about earth system for the prevention electric shock and a protection of equipment in england. The IEC60364 and BSI(British Standards Institution) define earthing method(IT, TT, TN-C, TN-S, TN-C-S)-BSI is british standards and in case of england almost use the TN system. TN system can classify TN-S & TN-C-S(PME). The findings on survey in england are used the TN-S system and TN-C-S system about 70% and residue 30% are used TT system and IT system from the exiting state of things.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.2
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• pp.59-66
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• 2000

In this paper we propose an approximation analysis for the system size distribution of the M/G/c system which is transform-free,. At first we borrow the system size distribution from the Markovian service models and then introduce a newly defined parameter in place of traffic intensity. In this step we find the distribution of the number of customers up to c. Next we concentrate on each waiting space of the queue separately rather than consider the entire queue as a whole. Then according to the system state of the arrival epoch we induce the probability distribution of the system size recursively. We discuss the effectiveness of this approximation method by comparing with simulation for the mean system size.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.329-332
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• 1997

This paper deals with the attitude control problem of nonlinear MIMO propeller setup. Multivariable GPC[Generalized Predictive Control] is adopted as the main controller, and it is implemented by TMS320C31 in the current paper. The main object of control is to move the propellers to wanted positions. System identification is performed to configure the system. Performance of the multivariable predictive controller implemented is shown via some experiments, which shows the controller meets the adequate control purpose.