• KIEAE Journal
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• 제17권3호
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• pp.15-21
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• 2017

Purpose: "Building energy design standard" is used to limit the thermal transmittance of building in Korea. However, it only covers the insulation standard for each appropriate elements of a building, not the thermal performance of Junction thermal bridge of windows and doors installed in wall. Therefore in this study, we have evaluated the thermal performance of Junction thermal bridge depending on installation method and position of windows and provide it as design data. Method: We analyzed heat transfer of 4-Track sliding window and tilt & turn triple glazed window that are placed in the first class category on window energy efficiency rating using Window 7.4 and Therm 7.4. Result : First, linear thermal transmittance of 4-Track sliding window differs by 2.2 times or more depending of installation method and location. It is higher than the linear thermal transmittance, 0.01W/mK, proposed by Passivhaus. Second, linear thermal transmittance of Tilt & turn triple glazed window differs by 7.7 times or more depending of installation method and location. The average linear thermal transmittance was less than 0.01W /mK when windows were installed on the internal wall insulation by the fixed hardware attachment method. Third, the thermal losses of a window caused by a junction thermal bridge are inversely proportional to the window area and converge gradually as the area increased.

• 한국재난정보학회 논문집
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• 제9권4호
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• pp.413-422
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• 2013

본 논문에서는 스프링클러설비가 설치된 대상물에서의 화재발생 시 인명피해 발생통계를 통하여 화재안전기준 요소의 성능을 분석하고 국내 화재안전기준 요소와 미국의 NFPA 13의 기준과의 비교를 통하여 성능을 분석함으로써 합리적이고 공학적인 화재안전기준 제정으로 인명 및 재산피해를 감소시킬 수 있는 개선방안에 대하여 연구하였다. 미국의 경우 스프링클러설비가 설치된 경우가 설치되지 않은 경우에 비하여 화재 당 사망률이 83 % 정도 낮았으나 국내의 경우 280 % 정도로 미국의 경우보다 3.37 배 높았다. 이와 같은 소화성능의 결여는 일률적인 용도분류, 화재하중을 고려하지 않은 수원의 양, 살수밀도를 고려하지 않은 기준개수 및 수평거리에 따른 스프링클러설비의 설치가 그 원인으로 분석되었다.

• 한국태양에너지학회 논문집
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• 제28권3호
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• pp.7-14
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• 2008

400RT geothermal system which is the biggest capacity among on-operations at present in Korea is measured and evaluated on 23rd${\sim}$26th Jan. 2008 during those days building is not allowed owners and/or tenants to move in. The geothermal system is consist with vertical-typed 112 geothermal heat exchangers which are installed circle-like 1 row with 4m interval, and has 16 units of 25USRT geothermal-source heat pump(GSHP)s. And each 5 units of circulation pump are running for geothermal heat exchangers and hot water supplies. The followings are the results. The temperatures at G.L. -70m of 2 boreholes are varied quite similarly. The average temperature difference between inlet and outlet of geothermal pipes is $4.1^{\circ}C$, and that of hot water supply is $3.2^{\circ}C$, of Zone 3's each 4 GSHPs when being operated. Despite temperature fluctuations by heating loads, the average temperature difference between main pipes of inlet and outlet of geothermal heat exchangers is measured as $4.1^{\circ}C$. This study propose "Geothermal System COP" which includes not only consumed electric power by compressor but also circulation pumps and auxiliary utilities. By comparing the geothermal system COP with GSHP's performance specification, it is clear that the performances of GHSPs of this site are satisfied with the specification.

• 한국지반환경공학회 논문집
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• 제24권1호
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• pp.25-36
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• 2023

국내 낙석, 토사 붕괴 등의 피해를 방지하기 위해 설치하는 것은 낙석 방지책이다. 이 중 낙석 방지울타리는 50kJ의 낙석 운동에너지에 설계가 되고 있다. 낙석 운동에너지의 경우, 발생하는 사면의 형태에 따라 크게 달라지며 기존의 연구로는 ETAG 27을 이용한 100kJ급 낙석 충돌에너지에 대한 울타리 성능평가를 실시하였다. 하지만 기존의 연구들은 낙석 방지울타리가 신규로 설치되는 것을 대상으로 하였다. 본 연구에서는 수치해석을 통해 신규 설치가 아닌 기존의 낙석 방지울타리에 보강부재를 설치하고, 120kJ의 낙석 운동에너지에 대해 방어할 수 있는 고강도 낙석 방지울타리의 구조 성능을 평가하였다.

• Journal of Biosystems Engineering
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• 제21권4호
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• pp.436-448
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• 1996

An earth tube soil air heat exchange system was designed, installed and operated as a single pass heat exchanger to utilize the geothermal energy as an natural energy source. This study was undertaken to investigate the potential of the heating and cooling, energy gain, heat exchange efficiency and coefficient of performance of the system. The system consisted of 30m in length and 30cm in diameter polyethylene pipes buried 2m deep in soil. Maximum heating and cooling performance were 2.51㎾ and 1.26㎾ at the air mass rate of 21cmm. Energy gain and coefficient of performance were the function of temperature difference between outside air and soil temperature. They were expressed as Q=0.33$ imes$$Delta T_{max}$+0.134(㎾) for energy gain and COP=0.44$ imes$$Delta T_{max}$+0.178 for coefficient of performance with correlation factor of 0.95. The mean of heat exchange efficiencies was 85.6%.

• 한국안전학회지
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• 제32권6호
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• pp.89-97
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• 2017

The tuned mass damper (TMD) system was first proposed as an efficient vibration control method for high-rise buildings, and multiple TMD (MTMD) system was then proposed for the purpose of improving the robust performance. Thereafter, the active TMD (ATMD) is proposed to improve the vibration control performance over the TMD and MTMD systems. However, this system may experience an system-instability problem in case of the actuator malfunction. In order to overcome such limitations of actuator malfunction causing the instability of the structural system, in this study, we investigate the feasibility of the multiple ATMD (MATMD) system that facilitates both advantages of the MTMD and ATMD. Numerical example demonstrates that, when the proposed system is designed to have the same capacity as the ATMD, it shows a similar control performance to the ATMD, but also has very good adaptive control performance against the emergency situations such as actuator failures.

• KIEAE Journal
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• 제10권3호
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• pp.51-56
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• 2010

The sound insulation performance is one of the important factor that determined the amenity of housing life in residential building. Especially, Apartment house represents a korea habitation. So the importance of privacy and noise problems between habitable rooms are emphasized in these habitation. This study investigates and find a problem of sound insulation performance of partition wall of the apartment house in current state. The measurements were carried out in apartment house with and without a stair hall. And the measurements also carried out in current state and installing a sound absorbing material in receiving room and changing a front door and installing a inner door. In spite of the same partition wall, difference results were showed according to the stair hall. It is appeared that sound insulation performance without stair hall is 6-7dB(Dw) higher than that with stair hall. In case of without stair hall, sound insulation performance is Dw 49 for single number quantity for airbone sound. And In case of changing a front door and installing a inner door sound insulation performance is Dw 57 for single number quantity for airbone sound. The Results of measuring on the changes a front door and installed a inner door indicated that the flanking sound through front door influenced the sound insulation performance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.282-291
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• 2010

In line with current speed-up of railroad, a slab track has been increasingly adopted in a bid to secure the safety of track structure as well as to reduce the maintenance cost, and furthermore, the need for commercialization of domestically-developed swing-nose crossing turnout on slab track has been on the rise. For commercialization of swing-nose crossing turnout on slab which was developed in Korea, a technical and systematic performance evaluation system, considering local environment, shall be established and then the performance evaluation shall be accordingly implemented. This paper was intended to summarize the performance evaluation system, referring to the data available at home and abroad and the results of performance evaluation for domestically-developed swing-nose crossing turnout on slab track carried out to date based on that system. A performance evaluation system comprises the technical requirement appropriateness evaluation(component performance evaluation and design verification), laboratory test and on-site test. For domestically-developed swing-nose crossing turnout on slab track, appropriateness evaluation and laboratory test have been completed and the on-site test of those installed on the 2nd phase of Kyung-Bu HSR is underway now.

• 한국멀티미디어학회논문지
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• 제18권12호
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• pp.1501-1508
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• 2015

In this paper, we describe a case study to improve performance through the load testing of multi-tired system for financial accounts before the system opening. The load test was conducted after the data collection tools(Performance Monitor, DB PSSDiag) were installed. By analyzing the collected log, we were able to identify the main sector requiring performance improvements among the presentation tier, web tier, business logic tier and data tier. The ASP.NET server-down on the web tier could be improved by modifying the parameter values in the configuration file. Some server downs occurred on the business logic tier when a large number of users access at the same time, were more difficult to be solved. By analyzing the hang-dump at the server-down time, we were able to find a process that caused the problem. and we had to modify the relevant codes. For major performance improvements of the data-tier, indices of some queries was optimized by using the built-in DBMS query analyzer, after analyzing the log of long-response-time queries. The problems and solutions considered in this case study will be a reference for the performance improvement of a multi-layer system with the similar structure.

• 한국유체기계학회 논문집
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• 제11권1호
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• pp.18-25
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• 2008

Recent trends of a centrifugal pump are high speed in rotation and high pressure in head with high efficiency to meet the demands of industries. However, the newly developed pumps make trouble of pressure pulsation in the pumping system by performance instability of the pump. Moreover, cavitation, which is a main obstacle of high rotational speed in the pump, occurring in an impeller gives serious damages to the impeller and casing wall. The purpose of present study is not only to develop a simple method to improve pump performance but also to suppress the occurrence of cavitation in the centrifugal pump by use of J-Groove. J-Groove is a shallow groove installed on the casing wall in the meridional direction. The application of J-Groove to a centrifugal pump with a new type impeller of "semi-closed impeller" has proved its effectiveness as a useful countermeasure of the unstable pump performance and cavitation. The results show that the combination of semi-closed impeller and J-Groove can be applied successfully and improves both the pump performance and suction performance.