• Journal of Energy Engineering
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• v.26 no.3
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• pp.90-96
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• 2017

When the hot water is supplied through the district heating (DH) pipeline, a pressure differential control valve (PDCV) protects the DH user equipment from the high pressure DH water and helps to supply DH water to long distance. It also controls the temperature and adjust the pressure in the main district heating pipeline. However, cavitation occurs in PDCV due to the use of high pressure DH water. It causes frequent failures and many problems. It also causes energy loss and complaints to both operators and users. In order to solve these problems, we will introduce the energy saving technology to replace the primary side PDCV with hydraulic turbine, convert the differential pressure into electricity, and utilize electricity as the power of the secondary side pump.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.131-140
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• 2016

Logistics service is a prerequisite for efficient market economy and to support the purchase and consumption by promoting smooth transport goods between economic actors. Especially, logistics activities of the company are the source of essential business activities and competitiveness, which is responsible for the production and distribution of products and services to be delivered to consumers. Domestic logistics companies have to resolve challenges such as petty status and low productivity, inefficiencies in the logistics industry system, limit the growth of third party logistics market according to the growth as 2PL central logistics companies, and absence of global leader in logistics enterprises. This study examines the definition and development of third party logistics and analyzes the domestic third-party logistics market conditions. Based on the former analysis, this paper presented separately the activated measures of domestic third-party logistics by corporate side, the supply side, and the government's policy support.

• Archives of Reconstructive Microsurgery
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• v.17 no.2
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• pp.115-119
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• 2008

Purpose: We reconstructed the skin defect of hands exposing tendons and/or bone with distally based ulnar artery flap and report our cases. Materials and Methods: Between March 2005 and September 2007, 6 cases of skin defect were reconstructed with distally based ulnar artery flap. Defect site were 5 cases of hand dorsal side and 1 case of hand volar side. The average defect size was $3{\times}3\;cm^2$. There were 4 men and 2 women and mean age was 55.5 years. We evaluated the viability of flap, postoperaive complication, healing time, patient's satisfaction. Results: There was no flap failure in 6 cases. But 1 case with recurrent discharge was healed with several times adequate debridement and delayed suture. 1 case with flap edema which might be due to venous congestion was healed with hand elevation and use of low molecular weight heparin. Mean time to heal the skin defect was 4 weeks. No infection and recurrence was found in follow up period. Cosmetic results as judged by patients were that 3 cases are good and 3 cases are fair. Conclusion: Distally based ulnar artery flap is good treatment method among the numerous methods in the cases of skin defect, with soft tissue exposed, which is not covered with debridment and skin graft. Distally based ulnar artery flap is useful method for the skin defect of hands because it is simple procedure, has constant blood supply and relatively good cosmetic effect.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.70-75
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• 2014

This paper presents a IR-UWB(Impulse Radio Ultra-Wide Band) transceiver circuit for data communication and real time location system. The UWB receiver is designed to OOK(On-Off Keying) modulation for energy detection. The UWB pulse generator is designed by digital logic. And the Gaussian filter is adopted to reject side lobe in transmitter. The measured sensitivity of the receiver is -65 dBm at 4 GHz with 1 Mbps PRF(Pulse Repetition Frequency). And the measured energy efficiency per pulse is 20.6 pJ/bit. The current consumption of the receiver and transmitter including DA is 27.5 mA and 25.5 mA, respectively, at 1.8 V supply.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.8
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• pp.517-525
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• 2008

In order to study the heat transfer and pressure drop of an internal heat exchanger for $CO_2$ heat pump under cooling condition, the experiment and numerical analysis were performed. Four kinds of internal heat exchangers with a coaxial tube type and a micro-channel tube type were used. The experimental apparatus consisted of a test section, a power supply, a heater, a chiller, a mass flow meter, a pump and a measurement system. The section-by-section method and Hardy-Cross method were used for the numerical analysis. The effects of the internal heat exchanger refrigerant flow rate, the length of the internal heat exchanger, the operating condition of the gas-cooler, the evaporator and the type of the internal heat exchangers were investigated. With increasing of the flow rate, the heat transfer rate increased about 25%. The heat transfer rate of the micro-channel tube type was higher about 100% than that of the coaxial tube type. With increasing of the length of the internal heat exchanger, the heat transfer rate increased about $20{\sim}50%$. The pressure drop of the low-side tube was larger compared with that of the high-side tube.

• Management & Information Systems Review
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• v.5
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• pp.139-160
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• 2000

Todays our private universities have been facing with serious survival competition according to the opening of education market, the diminishment of college voluntarists and the increase of education supply. In coming the beginning of the year of 2000, though the equal formula. 'The fixed number of students of universities = The number of graduates of high schools' will he formed, even though the tendency of the fixed number of students of universities is maintained as it is, and it has been expected the unlimited competition would be unvaoidable, so private universities and private junior colleges which are weak in financial power are roaring the crisis consciousness that they may have to close doors before making every effort. Based on such presentation of problem as its study object, the range of study is limitted to the educational financial portion related to higher education field. Especially, the financial portion of private universities of higher educational field is discussed in priority. Besides, the present status of financial condition of our universities was portionally compared with that of in the advanced nations. It is true that pursuing the academic superiority of university education in our country, and attaining object of university as well as developing reflection in future should stand side by side. Therefore, payment of fee, supporting subsidy, etc. is attached too much importance to the financial problem. In our country, the financial allotment is attached too much importance to national universities. This is against the principle of equity to the tax payers, and equality of opportunity, so the level of supporting national funds should be upward formed and supported from 1.0% to higher than 20%. In conclusion, our private universities should adopt as many alternatives of rationalization of finance as possible, such as securing lots of funds and subsidies, and rationalized management of finance, and ensuring finance according to the increasing number of students after university specialization, etc.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.69
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• pp.23-35
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• 2001

This paper attempts to identify the relationship between the business model and its financial performance through the construct of business paradigm, fit which may be defined as the congruence between the customer needs (the demand side) and the firm competence( supply side) to meet them, Each business model\`s business paradigm fit reflects how well the technology that business model has taken is interconnected with market. Basically, the business paradigm fit consists of two parts, product fit dealing with the product(s) to meet the customer needs well and process fit focusing on producing and/or providing that product(s) at the lowest costs. For empirical tasting the business paradigm fit matrix and the measures for them were developed and the data about 73 companies as sample were collects with questionnaires. The findings are: First business paradigm fit can be used as a strong empirical indicator for the firm performance, Second. balance fit in product or process gives to the most desirable outcomes and no fit brings about the worst ones. Third the over fit(the case of doing more excessive innovative efforts than to be needed) shows much better outcomes than the under fit(the case of doing less innovative efforts) Fourth, this paper shows where, in what situation, and what type of innovation has to be taken for firm success at firm level, whereas Schumpeter(1934) already indicated the importance of innovation for economic growth at the economy /industry level. However, further study should be done later with more refined measures and expanded sample data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.415-422
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• 2004

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz down-conversion mixer for DSRC communication system was designed and fabricated using 0.8 ${\mu}{\textrm}{m}$ SiGe HBT process technology and RF/LO matching circuits, RF/LO input balun circuits, and If output balun circuit were all integrated on chip. The chip size of fabricated mixer was 1.9 mm${\times}$1.3 mm and the measured performance was 7.5 ㏈ conversion gain, －2.5 ㏈m input IP3, 46 ㏈ LO to RF isolation, 56 ㏈ LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.350-357
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• 2005

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz up-conversion mixer for DSRC communication system was designed and fabricated using 0.8 m SiGe HBT process technology and IF/LO/RF matching circuits, IF/LO input balun circuits, and RP output balun circuit were all integrated on chip. The chip size of fabricated mixer was $2.7mm\times1.6mm$ and the measured performance was 3.5 dB conversion gain, -12.5 dBm output IP3, 42 dB LO to If isolation, 38 dB LO to RF isolation, current consumption of 29 mA for 3.0 V supply voltage.

• Journal of the Korean Society of Costume
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• v.57 no.8
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• pp.14-23
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• 2007

The purpose of this study was to investigate the present condition of cold protective clothing for mailman, to improve its design in movement, fitness, and other functions, and supply basic data for its performance evaluation. The results are as follows : The 46.60% of those questioned did not satisfy current clod protective clothing fer mailman. Especially, they considered dissatisfactory in properties such as waterproof, comfort, activity, and sweat absorption. The newly developed cold protective clothing is two-piece style composed of jacket and pants. Both jacket and pants are composed of inner and outer clothing individually. In both jacket and pants, their outer clothing's material was waterproof, windproof, and breathable shell fabric on which PTFE film laminated and their inner clothing's material was 100% polyester Polar polis to have better insulation property. The jacket has attachable cap which can be used as rain gear and set-in sleeve with stand collar. It also had big outside patch pockets and side seam pockets to ensure enough storage space. The pants have knee pads to give free movement to knees and slant side pockets. Inner clothing of both jacket and pants can be worn during working inside without out clothing. Insulation of the newly developed cold protective clothing was not better than current one except right hand, left hand and left foo. It is considered that is because thickness of material is the most important factor to influence insulation.