• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.46-51
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• 2018

A basic sprinkler system is a fire extinguishing system that can be easily installed in a fire-vulnerable place such as a publicly used establishments. However, the publicly used establishments are not only complicated in structure, but also have a large amount of flammable interior materials, and the users are not normally in a normal state, which is a very dangerous fire-fighting object. Therefore, due to the low fire extinguishing performance of the basic sprinkler system installed in the publicly used establishments, the fire suppression control can not be performed quickly in case of fire, which may increase the life and property damage. In this study, the cases of quantitative changes of extinguishing water used in basic sprinkler system and the cases of addition of additives such as wetting agents, reinforced agents to improve extinguishing performance were compared. Experimental results showed that the extinguishing performance was improved as the quantity of extinguishing water increase and the reinforced agents showed similar performance to that of 60% increase in the amount of extinguishing water. The cooling time to $200^{\circ}C$ and oxygen concentration were improved up to 14.3% and 34.5%, respectively. In the case of using the wetting agent, the cooling time to $200^{\circ}C$ and oxygen concentration did not show any significant improvement, but showed the effect of preventing deep seated fire. In order to prevent loss of life and property, it is necessary to improve the performance of the basic sprinkler system by increasing amount of extinguishing water or using additives like reinforced agents.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.15-22
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• 2014

Multiple devices have been installed to reduce exhaust emissions and to increase thermal efficiency. Those devices reduce the exhaust pipe opening area and increase the exhaust gas pressure. The pressure increase disturbs a gas flow and has a bad effect on the engine performance. However there is some study that NOx can be reduced with exhaust gas pressure increase. In this study an engine performance is tested with various opening ratios. The result shows that the fuel consumption rate is reduced in case of little amount of the pressure increase, and NOx is reduced with the pressure increase, while the concentration of the toxic exhaust gases are increased in the case of high back-pressure.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.1
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• pp.215-224
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• 2012

The purpose of this study is to investigate the external collaboration factors that affect the performance of Korean venture businesses. We use 1,567 firm data (from Venture Business Survey by Small & Medium Business Administration) and analyze the effect of the external collaborations with large business, research institutions, other small business, and foreign companies, on their sales increase between 2008 and 2009. Our analysis shows that Korean venture business' collaborations with research institutions or foreign companies increase their sales statistically significantly, while their collaborations with large business decrease their sales significantly. In the mean time, their collaborations with other small businesses show no significant result. Additional analysis on the collaboration categories between venture businesses and large businesses shows that collaborative R&D, employee training and collaborative marketing help venture business to increase their sales significantly, while financial collaborations have a significant negative effect on sales increase. Technology transfers and profit-sharing mechanism have no significant effect. The result shows that venture business' collaborations for the increase in the fundamental capability of innovations and for searching new markets rather than simple transfer of technology or financial collaborations, have significant positive effects on the increase in sales.

• Information Systems Review
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• v.22 no.2
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• pp.121-135
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• 2020

Since many researchers were interested in measuring the performance of information technology investment, many studies have been conducted with various data sources and analysis methods, and most studies report that IT investment produces significant and positive results. Many of these studies have been conducted at the enterprise level, but different results may occur at the industry level. In the case of the electronics industry, if the performance of the IT highly increases, the sales of the IT produced in the electronics industry may decrease, and the added value of the electronics industry may also decrease. As a result of analysis, the increase in the IT capital of the US electronic industry did not increase the added value of the industry, but the increase in IT capital per worker in the industry had a positive effect on the increase in value added per worker (labor productivity) in the industry. In addition, the increase in IT capital in the US electronics industry has resulted in a decrease in the number of workers.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.433-436
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• 1998

Hot carrier induceed the performance degradation of sense amplifier circuit in DRAM has been measured and analyzed using 0.8.mu.m CMOS process. Simulation and experimental results show that the degradation of the MOS devices affects the decrease of the half-Vcc, voltage gain and the increase of the sensing voltage gain and the increase of the sensing voltage. The dominant degradation mechanism is the capacitance imblance in the bit-line pair. We carried out the spice simulation to investigate the degradation of the sense amplifier circuit.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.611-616
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• 1994

Developing the safety training program has been a major research topic in CBT as well as in traditional teaching and learning. With regard to determining learning control in CBT, it is important to consider not only the characteristics of learning tasks but also student's individual difference. In this regard, the purposes of this study are to develop the CBT program as well as animation program in order to increase the student's performance.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.591-594
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• 2001

In the W-CDMA system, cell search is one of the imporant functions of the mobile station searching for a cell and achieving spreading code and time synchronization to its downlink scrembling code. For the methods of cell search to optimize codes, three stages are considered: 1) slot synchronization, 2) frame synchronization, and 3) scrambling code identification. Channels for cell search are Primary Synchronization Channel (P-SCH), Secondary Synchronization Channel(S-SCH), and Common Pilot Channel (CPICH). In this paper, cell search is analyzed based on simulation. Rake receiver provides improvement of Performance as an increase of bandwidth because there are more available multipaths. In this paper, the performance of W-CDMA system employing RAKE receiver is evaluated by computer simulation over the types of ITU_R wideband channel model and spreading rate. The result shows that the performance of CDMA adapting RAKE receiver is improved by the increase of multipath components in equal level of the received power.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.11-17
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• 2011

The numerical study was conducted to investigate the pump performance due to impeller related parameters change in centrifugal pump of very low specific speed by using CFD code. A small centrifugal pump whose specific speed is $N_s=76.2$ was used, and the performance characteristics were discussed for different number of vanes, rotational speed, and the length and height of vane. The numerical results at a very low specific speed show that the increase of the number of vanes has little effect on improvement of output pressure but results in the reduction of pressure fluctuation, and that the head increases with the increase in the rotational speed. The decreasing the length of vane has a considerable reduction of the capacity coefficient in comparison with decreasing the height of vane.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.153-156
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• 2005

Skin region detection in images is an important process in many computer vision applications targeting humans such as hand gesture recognition and face identification. It usually starts at a pixel-level, and involves a pre-process of color spae transformation followed by a classification process. A color space transformation is assumed to increase separability between skin classes and other classes, to increase similarity among different skin tones, and to bring a robust performance under varying imaging conditions, without any complicated analysis. In this paper, we examine if the color space transformation actually brings those benefits to the problem of skin region detection on a set of human hand images with different postures, backgrounds, people, and illuminations. Our experimental results indicate that color space transfomation affects the skin detection performance. Although the performance depends on camera and surround conditions, normalized [R, G, B] color space may be a good choice in general.

• Journal of Hydrogen and New Energy
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• v.20 no.4
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• pp.283-290
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• 2009

This study focuses on the performance characteristics of polymer electrolyte membrane fuel cell (PEMFC) using the AC impedance technique. The experiment was carried out to investigate the optimal operating conditions of PEMFC such as cell temperature, flow rate, humidified temperature and back-pressure. The fuel cell performance was analyzed by DC electronic-loader with constant voltage mode and expressed by voltage-current density. Additionally, AC impedance was measured to analysis of ohmic and activation loss and expressed by Nyquist plot. The results showed that the cell performance increased with increase of cell temperature, air flow rate, humidified temperature and backpressure. Also, the activation loss decreased as the increase of cell temperature, air flow rate, humidified temperature and backpressure.