• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2147-2150
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• 2003

Recently, many technologies of the P.L.C (Power Line Carrier) are introduced for an efficient communication. P.L.C communication sends information in the carrier signals by conduction over the power wire. An arc detector is proposed in this paper for the effective transmission. The Power Line Carrier has an advantage in low cost because it uses existent power line. It can be easily applied anywhere that a power line socket is available. But the P.L.C. is very noisy, because many electronic devices in generate electronic noise in modulated signals. This problem should be considered carefully in the design of the arc detector system using P.L.C in railway. The proposed system can be applied for monitoring the arc detector system and the arc locator system in railway. Hence the system will be able to exchange the arc information to be T.C.M.S. (Train Control Management System), bogies and even between a station and trains in railway and use to suspicion fire in train.

• Solar Energy
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• v.20 no.3
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• pp.11-19
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• 2000

In this study, the basic data which were required for development of LHSS(latent heat storage system) were experimentally obtained. Experiments were carried out under the following conditions. The initial temperatures of P.C.M. which were used by parameter is $5^{\circ}C,\;9^{\circ}C$ and $14^{\circ}C$. The conditions of working fluid are $-6^{\circ}C,\;-4^{\circ}C$, and $65{\ell}$/min.. The pure water of which the freezing point is $0^{\circ}C$ was filled in the system, and the Ethylene glycol(brine) was circulated through the 10 vertical tubes as a secondary fluid in order to cool the P.C.M. down. The inlet temperature of the secondary fluid and the initial temperature of the water were varied to investigate the effects of the important design parameters. The phenomenons of temperature conversion of P.C.M. were appeared for the conductive heat transfer and free convective heat transfer by buoyancy force in this storage unit system. In order to find the effective water circulation path, we obtained P.CM. temperature distributions of 5 parts in the storage tank during freezing process.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.37-44
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• 2015

A queueing system with 2 parallel workstations is common in the field. Typically, the workstations have different features in terms of the inter arrival times of customers and the service times for the customers. Computer simulation study on the optimal server allocation for parallel heterogeneous queueing systems with fixed number of identical servers is presented in this paper. The queueing system is optimized with respect to minimizing the weighted system time of the customers served by 2 parallel workstations. The system time formula for the M/M/c systems in Kendall's notation is known. Thus, we first compute the optimal allocation for parallel M/M/c systems, comparing the results with those from the computer simulation experiments, and have the same results. The CETI rule is devised through optimizing M/M/c cases, which allocates the servers based on Close or Equal Traffic Intensities between workstations. Traffic intensity is defined as the arrival rate divided by the service rate times the number of servers. The CETI rule is shown to work for M/G/c, G/M/c queueing systems by numerous computer simulation experiments, even if the rule cannot be proven analytically. However, the CETI rule is shown not to work for some of G/G/c systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.103-111
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• 2001

During cold-start period, the reduction of exhaust emissions is a challenging task. To decrease harmful gaseous substances such as HC, it is necessary to realize a fast catalyst warm-up. In this study, the performance of dual pipe exhaust system have been carried out through different test mode. From measurement of gas temperature and HC concentration, the following conclusions were derived ; 1) Compared with single pipe, dual pipe exhaust system remarkably increase temperature of exhaust gas going through M.C.C(Main Catalytic Converter). 2) W.C.C.(Warm-up Catalytic Converter) also decreases HC emission. To reduce HC emission, it is helpful to use W.C.C. as well as dual pipe exhaust system. 3) Using finite element method, it is shown that inner parts have much higher distribution of temperature than outer parts.

• Journal of the Korea Institute of Building Construction
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• v.9 no.6
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• pp.99-104
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• 2009

This study is the basic design of a P-C-M support system for Agricultural Facilities. By utilizing this system, many users of Agricultural Facilities can easily obtain a large amount of information, ranging from procurement to maintenance. The procurement phase suppliesthe user with agricultural facilities information, economical analysis, and corporation information for procurement decisions. Furthermore, this phase shows the shape or format of the agricultural facilities, the main materials, as well as information on the cultivated crops. The construction phase shows information about agricultural facility-related laws, as well as standard drawings or a construction guide. The maintenance phase shows a guide of maintenance-related checklists. With the results of a basic design of a P-C-M Support System for Agricultural Facilities, the P-C-M support system menu tree is established.

• Journal of applied mathematics & informatics
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• v.30 no.3_4
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• pp.531-540
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• 2012

An approximation for the number of customers at service facility in $M/G/c/K$ retrial queue is provided with the help of the approximations of ordinary $M/G/c/K$ loss system and ordinary $M/G/c$ queue. The interpolation between two ordinary systems is used for the approximation.

• Journal of the Korea Fashion and Costume Design Association
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• v.5 no.3
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• pp.1-6
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• 2003

The purpose of this study was to investigate the dyeability and color fastness of cotton and silk fabrics dyed with extract of Arrowroot leaf princeps. The experimental items were divided into the mordant treatment, component of fabric and kind of mordants. The experimental study was done by laundering, abrasion(dry/wet), perspiration(acid/alkali), light fastness, color difference by C.C.M system and K/S test. The summerized finding reulted from experiment and investigation are suggested as follows : In the C.C.M and K/S test on mordanting method and kind of fabric, that of silk and cotton was the most effective in the pre mordant treatment. In the C.C.M and K/S analysis on 5 mordants, that of silk and cotton was significantly improved when mordants was treatmented. Especially, that of Fe mordanting treatment was higher than Al, Cu, Cr and none. In color fastness on mordants, laundering, perspiration and abrasion fastness showed 4-5 grade but light fastness showed 1-3 grade.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1159-1168
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• 2020

In the past, control and monitor of a large number of instruments is a specialized area, which requires an expensive dedicated module to implement. However, with the recent development of embedded technology, various products capable of performing M&C (Monitor and Control) have been released, and the scope of application is expanding. Accordingly, it is possible to more easily build a small M&C environment than before. In this paper, we discussed a method to replace the M&C of the VLBI system, which had to be implemented through a specialized hardware product, with an inexpensive general imbeded technology. Memory based data transmission, reception and storage is a technology that is already generalized not only in VLBI but also in the network field, and more effective M&C can be implemented when some items of Ethernet are optimized for the VLBI (Very Long Baseline Interferometer) system environment. In this paper, we discuss in depth the design and implementation for the multidrop based IoT architecture.

• Journal of the Korean Ceramic Society
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• v.18 no.3
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• pp.192-200
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• 1981

This study deals with the low temperature ($25^{\circ}C$-$600^{\circ}C$) properties of Kaolin-Phosphate-water systems. Phosphoric acid, mono aluminum phosphate, mono ammonium phosphate, the mixture of phosphoric acid and mono aluminum phosphate, and the mixture of phosphoric acid and mono ammonium phosphate were used to characterize the M.O.R. of the systems with to quantity of phosphates, curing time, and firing temperature. Firing shrinkage, viscosity, surface tension, DTA, TGA, and X-ray diffraction patterns were also measured in order to investigated the factors of strengthening. The results of this study were summarized as follows: 1. The M.O.R. of kaolin-phosphate systems were stronger than that of Kaolin-water system at room temperature or low temperature($25^{\circ}C$-$600^{\circ}C$). Though it was increased according to the longer curing time, the higher temperature, and the more addition of phosphate, the M.O.R. were decreased in the case of 10 wt% phosphate addition in the system of phosphoric acid, mono aluminum phosphate and phosphoric acid-mono aluminum phosphate. 2. When the concentration of Phosphate was at 4 wt%, the M.O.R. of specimen cured at $25^{\circ}C$ and added to the phosphoric acid was strongest among the specimens in added to the others phosphates. Whereas, when the concentration of phosphate was above 6wt%, the M.O.R. of specimen cured at $25^{\circ}C$ and added to the phosphoric acid mono ammonium phosphate system cured at $25^{\circ}C$ was the strongest. 3. The M.O.R. of the specimen heated, in the temperature range of 15$0^{\circ}C$-1$600^{\circ}C$, and added to the mixture of phosphoric acid-mono aluminum phosphate system or phosphoric acid-mono ammonium phosphate system was stronger than that of specimen added to Phosphoric acid, mono-aluminum Phosphate or mono-ammonium phosphate alone. 4. The bonding force of phosphate binders was more closely related to surface tension than viscosity and it tended to be inversely proportional to surface tension. The bonding force after heating treatment seemed to be caused by the change of structure of phosphate according to heating.

• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.244-251
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• 1993

A novel system has been developed to produce ${\delta}-aminolevulinic$ acid (ALA) using the intact cells of late logarithmic phase of Rhodocyclus gelatinosus KUP-74. The system was shown optimum yield of extracellular ALA under a condition of anaerobic light irradiation (4 Klux) at $30^{\circ}C$ with no variation in cell mass. The rate of extracellular ALA formation was stimulated by low doses of either $C_4\;or\;C_5$ ALA biosynthetic precursors, where 5 mM ($C_4) and 3 mM ($C_5) of each precursors were appeared to generate the maximum rates of 3.3 and 4.0 nmoles of ALA per 0.35 mg cells per hr, respectively. Half-life of the system was 10 hr in a sense of an ability of portage transport of L-glutamate, and sequential dose of this compound was resulted in promising recovery of the ALA.