• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.534-542
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• 2012

Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As a result, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.76.2-76.2
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• 2021

We present the characterization of the performance of the next-generation controller (SDSU Gen III) for BOAO Echelle Spectrograph CCD (BOES CCD) at the Bohyunsan Optical Astronomy Observatory. The current controller (SDSU Gen II) of the BOES CCD will be upgraded to SDSU Gen III to provide a more stabilized operation. To assess the performance of the new controller (e.g., conversion gain, full well capacity, S/N), we obtain various types of calibration images (e.g., bias, flat, science images of standard stars). Based on those datasets, we find that the overall performance of the new controller is somewhat comparable to that of the old controller if the slow mode is adopted for the readout. This may demonstrate that the new controller can be successfully substituted for the old controller without a substantial loss of performance. However, further analysis with a large dataset obtained in various observational conditions is necessary to confirm our results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1054-1059
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• 2005

To support the expansion of the autonomous robot market, the establishment of evaluation standards of the robot performance are essential. In this paper, to venture the standardization of the performance evaluation of the autonomous robot, the authors take the autonomous cleaning robot(ACR) as the initial stepping stone. Recently, the ACR has been being developed and marketed actively in many countries including Korea and it believes to be the fore-runner among various types of autonomous robot products. Standards of the performance evaluation for the ACR could be easily modified and applied to other autonomous robots. This paper formulates and suggests a group of standards for the performance evaluation based on a evaluation platform for the ACR. The newly developed performance evaluation platform has been designed to include all the important aspects of living environments in reality. In the platform the performance of the ACR is measured in terms of mobility, cleaning performance, avoidance of obstruction(safety), and operation noise. A few commercially available ACR products are collected and tested in the evaluation platform and compared against the performance evaluation standards formulated.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1187-1192
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• 2016

Performance analysis results are limited to of network level, because network level transmission parameters are used for performance measure and analysis of network design, construction and operation on underwater MANET, With this way of performance analysis based on network level, it is not easy to analyze transmission performance related with user level transmission quality. In this paper, transmission performance focused on application traffic be required by user is investigated to supplement weakness of performance analysis based on network level. Voice traffic, which is expected to be increasingly used on underwater MANET, is considered as application service, Some conditions for underwater MANET will be proposed to support transmission quality, MOS, CCR and EED, etc.. A computer simulation based on NS-2 is used for performance measure, voice traffic is generated as VoIP specification.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1083-1088
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• 2019

Even though the transmission performance is very important factor for not only study and development but also for design, implementation, and operation of underwater MANET. There is a trend of using it as a measurement factor for comparing and analyzing degree of network performance. In this paper, movement pattern using transmission performance is analyzed to enlarge the use of transmission performance in underwater MANET. The relation between transmission performance and movement pattern is firstly considered and then through this consideration, causing effects of movement pattern to transmission performance is studied. Results of this study can be used as an important base to predict and analyze movement pattern through measuring of transmission performance of moving objects in underwater environments.

• Journal of Distribution Science
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• v.17 no.11
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• pp.35-45
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• 2019

Purpose: The purpose of this study is to suggest strategic implications about empirical analysis with mediation effects of corporate image in terms of that relations between logistics culture safety, safety compliance and logistics performance of logistics companies. Research design, data and methodology: The structure and method of this research is organized with, first establishing hypothesis and research model based on previous study related to safety culture, safety compliance, corporate image, logistics safety and logistics performance, which has been carried out survey questionnaire to those who got involved in logistics businesses. Results: It is well justified that safety culture and safety compliance have significantly influenced to logistics performance as well as corporate images that is also revealed to have positive impact to logistics performance. With results verifying into mediation effects of corporate image, it is found that corporate image has partial mediation effects between logistics safety culture and logistics performance, and corporate image has full mediation effects between logistics safety compliance and logistics performance. Conclusions: In conclusion, it is strongly asked to make an aggressive efforts to safety compliance with necessity for spread of safety culture in level of enterprise. Planning the strategy and its implementation is required to secure safety in logistics process because both logistics performance and corporate image has positive influences by logistics safety.

• Journal of ILASS-Korea
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• v.19 no.1
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• pp.19-24
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• 2014

In this study, the cooling performance of a liquid CPU cooler using the water/propylene glycol(PG)-based $Al_2O_3$ nanofluids is experimentally investigated. Water/PG-based $Al_2O_3$ nanofluids are manufactured by two-step method with ultrasonic energy for 10 hours. The volume fractions of the nanofluids are 0.25% and 0.35%. Thermal conductivity and viscosity of the nanofluids are measured to theoretically predict the thermal performance of the liquid CPU cooler using performance factor. Performance factor results indicate that the cooling performance of the liquid CPU cooler can be improved using the manufactured nanofluids. To evaluate the cooling performance of the liquid CPU cooler experimentally, temperature differences between ambient air and heater are measured for base fluid and nanofluids respectively. Based on the results, it is shown that performance of the liquid CPU cooler using $Al_2O_3$ nanofluids is improved maximum up to 8.6% at 0.25 Vol.%.

• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.325-336
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• 2006

This research analyzes clean room major fire prevention standard of clean Room (FM, IRI, and NFPA Code), the structure of Performance-Based Fire Safety Design (PBD) applied the korean fire industry situation. Performance-Based Fire Safety can operate effectively the performance of fire protection equipment & building design, so the fitness of fire safety system can be embodied by operating this. moreover, cost to be consume fire safety of real building can reduce and Performance-Based Fire Safety is considered to important technique in fire protection field. A fire in a clean room may cause a serious loss by spreading smoke particles. We will be investigated by using a computational fluid dynamics, for loss prevention by smoke spreading from one fire area to another for clean room and compared the Performance-Based Fire Safety Design with the prescriptive code design. The methodology of fire safety performance-based fire safety design and guarantee of many kinds design skill of fire system and developing design procedure will be very serious one in order to improve efficiency of domestic system. Therefore, This research will be contributing to secure safety of clean room and to set up the performance-based fire safety design in Korea by regulation for the performance-based fire safety design effectively.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.289-300
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• 2010

The purpose of this study is to examine the effect of psychological capital on empowerment and learning performance and the mediating effect of the empowerment on the relationship between psychological capital and learning performance. In order to verify the relationships and mediating effect, data were obtained from 283 university students in Ulsan Metropolitan City and were analyzed by using SPSS 12.0, AMOS 5.0. The findings are as follows: First, the psychological capital were positively related to the empowerment and the learning performance. Second, there was also a positive relationship between the empowerment and the learning performance. Finally, it is found that empowerment fully mediated the relationship of psychological capital and earning performance. The theoretical implication of the study includes that this study and findings advance the understanding of learning performance by suggesting a new viewpoint regarding how psychological capital and empowerment to motivate university's learning performance. Based on these findings, the implications and the limitations of the study were presented including some directions for future studies.

• The Journal of Industrial Distribution & Business
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• v.9 no.1
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• pp.9-23
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• 2018

Purpose - The purpose of this paper is to investigate the potential benefits or detriments of team management on fund performance in the mutual fund market. An additional purpose of this study is to examine the optimal number of managers in a fund industry for superior performance. Research design, data, and methodology - This paper investigates the effect of managerial structure on fund performance in the Korean active mutual fund market between 2001 and 2008. For this, we analyze two risk-adjusted performances measures- the capital asset pricing model (CAPM) and the three-factor model of Fama & French (1993). Results - First, we found that single-managed funds exhibited superior performance. Second major finding was that as the number of managers in a fund increases, the fund performance deteriorates. Finally, the results reveal that the sharpest performance drop occurs when team size increases from a 5-person team to a 6-person team. Conclusions - The results suggest that the management structure can be a source of competitive advantage for fund performance. As considering fund performance is the outcome of managers' decision-making, this study contributes to not only the financial literature but also the literature in other areas, such as management and general business.