• 상하수도학회지
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• 제21권6호
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• pp.755-761
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• 2007

Disinfection performance in clearwell is generally measured by CT, which is expressed by $C{\times}T$. C is represented by disinfection concentration, and T is represented by $T_{10}$ which means 90% contact time in clearwell. In order to improve Disinfection performance, augmentation of $T_{10}$ is required. Guide wall has been generally used to improve $T_{10}$ because $T_{10}$ changes according to flow field. In this study, porous media is proposed instead of guide wall, and disinfection performance between guide wall and porous media wall are compared. Flow field and $T_{10}$ in each clearwell are investigated as well. Improved Disinfection performance appear in case of porous media wall compare to guide wall, and best performance occur in porosity factor ${\beta}$ 1e+4.

• Journal of Biosystems Engineering
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• 제27권6호
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• pp.491-500
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• 2002

This study was carried out to investigate experimentally the effect of the tire inflation pressure of a tractor on soil compaction and tractive performance. Two kinds of field experiments were conducted using an agricultural tractor. One experiment is concerned with the tractive performance of the tractor at the three levels of tire inflation pressure; 50kpa, 100kpa and 200kpa, and the other one is about the soil compaction at the four levels of tire inflation pressure; 50kpa, 100kpa, 150kpa and 200kpa, at three different numbers of passes; 1, 3 and 5 passes. From the results of the field experiment, it was found that decreasing the tire inflation pressure decreased the motion resistance of tractor and increased the tractive force and tractive efficiency. The tractive and working performance of the tractor could be improved by the reduction of tire inflation pressure. Increasing the inflation pressure and the number of passes increased the soil compaction. Rate of compaction increased rapidly at the first pass and declined at subsequent passes. To reduce the effect of soil compaction for the whole field, it is recommended that tractor should follow the rut of the first pass from the subsequent passes, and decrease the inflation pressure of the driving tires up to allowable minimum level.

• 한국재난정보학회 논문집
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• 제8권3호
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• pp.234-241
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• 2012

본 연구의 주 목적은 다층 구조를 가진 아스팔트 포장체의 피로균열에 대한 공용성 예측모델을 검정하는 것이다. 그러나, 검정 인자는 목표로 하는 예측모델, 시험법 및 시험중 하중이력에 따라 차이가 있을 수 있다. 본 연구에서 수행된 다양한 현장 조사에 의하면, 연성포장의 피로공용성은 교통하중뿐만 아니라 포장체의 완성후 경과기간에 영향을 받는 것으로 나타났다. 이에 따른 각각의 교통하중과 경과기간에 대한 가중치가 본 연구에서 제시되었다. 또한, 기 발표된 피로 예측모델을 바탕으로 실내와 현장조사를 통하여 얻어진 피로균열 데이터의 상호 상관관계를 분석하여 피로 예측모델에 대한 검정 인자가 개발되었다.

• 대한영양사협회학술지
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• 제15권2호
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• pp.113-127
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• 2009

This study was conducted to evaluate the sanitary performance and education of middle and high school foodservice employees in Seoul, South Korea in order to ensure the foodservice safety and identify why some employees cannot apply learned knowledge in real work situations. Subjects consisted of 217 school foodservice employees who attended a regular sanitary education program under the auspices of the Seoul Gangdong and Gangseo district offices. The sanitary performance was assessed with 5 dimensions (personal hygiene, ingredient control, process control, safety management and sanitary education), and was self-evaluated using a Likert 5 point scale. The data were analyzed using the SPSSWIN Version 12.0 package. The main results of the study showed that according to the general characteristics of middle and high school foodservice employees, 98.2% of respondents were women, and 64.1% of them aged 40-49. A total mean score of 5 items of sanitary performance for middle and high school employees was 4.74. Ingredient control field score was 4.83, process control 4.80 and personal hygiene 4.74. In contrast, the sanitary education field score was 4.56, significantly lower than the total mean score. Safety management field score was 4.71. Verbal education was the main method performed as a sanitary education in schools.

• 반도체디스플레이기술학회지
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• 제15권4호
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• pp.1-9
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• 2016

The warpage on mobile phone camera packages occurs due to the CTE(Coefficient of Thermal Expansion) mismatch between a thin silicon die and a substrate. The warpage in the optical instruments such as camera module has an effect on the field curvature, which is one of the factors degrading the optical performance and the product yield. In this paper, we studied the effect of die bonding epoxy on the package and optical performance of mobile phone camera packages. We calculated the warpages of camera module packages by using a finite element analysis, and their shapes were in good agreement showing parabolic curvature. We also measured the warpages and through-focus MTF of camera module specimens with experiments. The warpage was improved on an epoxy with low elastic modulus at both finite element analysis and experiment results, and the MTF performance increased accordingly. The results show that die bonding epoxy affects the warpage generated on the image sensor during the packaging process, and this warpage eventually affects the optical performance associated with the field curvature.

• 산업경영시스템학회지
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• 제37권1호
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• pp.79-90
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• 2014

The Purpose of this study is to empirically examine the impact of various internal and external innovation activities of SMEs on their innovation performances in the field of electronics and communication industry. Drawing upon the literature review, internal and external innovation activities are defined and conceptualized, and independent, dependent and moderator variables are developed. We have used survey-based data for this study from the survey of technology innovation activities in manufacturing industry, which was conducted by the Science and Technology Policy Institute (STEPI) in 2010. The main result of this study shows that there were no significant differences in the impact of innovation activities on market performance according to the size of SMEs. On the other hands, we found that there were significant differences in the impact of innovation activities on technological innovation performance according to the size of SMEs. Therefore, in order to make high technological innovation performance, companies in the field of electronics and communication industry need to properly implement the internal and external innovation activities by considering their size.

• 한국IT서비스학회지
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• 제17권4호
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• pp.191-208
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• 2018

This study explores the role of knowledge sharing activities among team members and performance in R&D setting. Knowledge sharing activities are classified into two : Knowledge sharing activity within/outside team. And the relationships between the knowledge activities and R&D performance are also examined according to three R&D stages : basic, applied, and developmental research. A empirical study was conducted at a research institute of large company that leads the advanced research and development of the domestic chemical industry. Data was collected 292 copies out of 500 copies (Response rate 58.4%). The result indicated that knowledge sharing within and outside the team has a positive effect on R&D Performance. In particular, knowledge sharing within the team has a greater effect on R&D outcomes in basic research stage. Knowledge sharing outside the team has a greater effect on R&D outcomes in the development research stage. In the R&D organization, it is important that members of the team are well-connected and understanding each other, but they should encourage positive relationships with external members of the team. Depending on the R&D field of the team, the basic research field should concentrate more on knowledge sharing within the team, while the development research field should focus more on knowledge sharing outside the team.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.262-270
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• 2004

Basic experiments were carried out using the THT-IV low-power Hall thruster to examine the influences of magnetic field shape and strength, and acceleration channel length on thruster performance and to establish guidelines for design of high-performance Hall thrusters. Thrusts were measured with varying magnetic field and channel structure. Exhaust plasma diagnostic measurement was also made to evaluate plume divergent angles and voltage utilization efficiencies. Ion current spatial profiles were measured with a Faraday cup, and ion energy distribution functions were estimated from data with a retarding potential analyzer. The thruster was stably operated with a highest performance under an optimum acceleration channel length of 20 mm and an optimum magnetic field with a maximum strength of about 150 Gauss near the channel exit and with some shape considering ion acceleration directions. Accordingly, an optimum magnetic field and channel structure is considered to exist under an operational condition, related to inner physical phenomena of plasma production, ion acceleration and exhaust plasma feature. A new Hall thruster was designed with basic research data of the THT-IV thruster. With the thruster with many considerations, long stable operations were achieved. In all experiments at 200-400 V with 1.5-3 mg/s, the thrust and the specific impulse ranged from 15 to 70 mN and from 1100 to 2300 see, respectively, in a low electric power range of 300~1300 W. The thrust efficiency reached 55 %. Hence, a large map of the thruster performance was successfully made. The thermal characteristics were also examined with data of both measured and calculated temperatures in the thruster body. Thermally safe conditions were achieved with all input powers.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권3호
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• pp.208-215
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• 2011

A full-scale field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. The first Korean icebreaking research vessel 'ARAON', after her delivery in late 2009, had a sea ice field trial in the Arctic Sea during July-August, 2010. This paper describes the test procedures and data analysis on the icebreaking performance of the IBRV ARAON. The data gathered from the icebreaking performance test in the Chukchi Sea and the Beaufort Sea during the Arctic voyage of ARAON includes the speed and engine power of the ship as well as sea ice thickness and strength data. The air temperature, wind speed and heading of the ship were also measured during each sea ice trial. The ARAON was designed to break 1 m thick level ice with a flexural strength of 630kPa at a continuous speed of 3knots. She is registered as a KR POLAR 10 class ship. The principal dimensions of ARAON are 110 m, 19 m and 6.8 m in length, breadth and draft respectively. She is equipped with four 3,500kW diesel-electric main engines and two Azipod type propulsion motors. Four sea ice trials were carried out to understand the relationship between the engine power and the ship speed, given the Arctic ice condition. The analysis shows that the ARAON was able to operate at 1.5knots in a 2.5m thick medium ice floe condition with the engine power of 5MW, and the speed reached 3.1 knots at the same ice floe condition when the power increased to 6.6MW. She showed a good performance of speed in medium ice floe compared to the speed performance in level ice. More detailed analysis is summarized in this paper.

• 대한건축학회논문집:구조계
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• 제34권12호
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• pp.41-49
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• 2018

The current housing performance rating system displays the performance rating of the houses supplied by the housing construction company, approved by the Housing Law. This system is intended to provide accurate information to the consumers in the announcement of the tenant recruitment, thereby improving the quality of the housing. This system was revised in January 2005 and implemented from January 2006. It is obligatory for companies with a scale of more than 1,000 households (energy performance rating is over 300 households), but there is currently no content on the waterproofing field. Therefore, this study suggests the revision plan proposes the necessity of the inclusion of the performance grade for the waterproofing field which is not currently implemented in the apartment house performance rating system, and to understand how to secure an adequate living environment. As a result, according to survey results, the performance score based on the difficulty of the maintenance method according to future leaks was selected and the revised system was prepared. Based on this, the performance grade for the virtual apartment was evaluated, and the results show that the performance of various grades is presented accordingly.