• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.3
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• pp.210-215
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• 2002

In this study, the computer program called Multi_Cycle, which simulates the steady-state performance (coefficient of performance, capacity, power consumption and etc.) of multi- airconditioning systems using R410A, was developed. In order to validate the simulation program, a series of case studies were carried out. The Multi_Cycle consists of several subroutines for simulating indoor units. outdoor unit, compressor, and expansion devices. and for estimating the thermodynamic and transport properties of the refrigerants and moist air. It would appear to be advantageous to use the Multi_Cycle for a performance analysis when considering various kinds of refrigerants and the complex operating conditions of each unit making up the multi-airconditioner cycle. Moreover, the Multi_Cycle would seem to be useful tool in optimizing a multi-airconditioning system and establishing economical and efficient operating conditions in the multi-airconditioner cycle. In the present study, the Multi_Cycle was programmed with Digital Visual Fortran for the main simulation code and Visual Basic for- the graphic user interface.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.85-92
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• 2020

Following the development of Internet of Things (IoT) technology, the scope of application of IoT technology is expanding to industrial safety areas that detect and prevent possible risks in outdoor environments in advance, away from improving the convenience of living in indoor environments. Although this expansion of IoT service provides many advantages, it also causes security problems such as data leakage and modulation, so research on security response strategies is being actively carried out. In this paper, the IoT-based road construction risk management system in outdoor environment is proposed as a research subject. As a result of investigating the security vulnerabilities of the low-power wide-area (LPWA, BLE) communication protocol applied to the research targets, the security vulnerabilities were identified in terms of confidentiality, integrity, and availability, which are the three major elements of information security, and countermeasures for each vulnerability were proposed. This study is meaningful in investigating and analyzing possible vulnerabilities in the operation of the IoT-based risk management system and proposing practical security guidelines for each vulnerability.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.345-346
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• 2003

서울시 지하철은 1974년 1호선을 시작으로 현재 8호선까지 운행되고 있으며, 40 ％이상의 높은 수송 분담율을 기록하고 있다. 또한 이용 승객의 증가와 함에 주변의 지하상가와 역세권을 형성하여, 주요 교통수단 및 서울시민의 중요한 생활공간으로 자리 잡게 되었다(한근혁, 2002). 그러나 서울시 지하철의 지하역사는 실외공간과 달리 공간적 밀폐성으로 공기질 악화문제에 직면하고 있다(환경부, 2002). (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.181-182
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• 2001

도시 집중화로 교통난과 토지 과부족 현상이 야기되었으며, 초고층빌딩과 지하공간의 개발이 급속히 진행되고 있다. 또한, 지하공간의 이용률 급등에 따라 지하공기를 포함한 실내공기질에 관한 관심이 높아지고 있다. 기존 연구문헌에 의하면, 현대인의 대부분은 하루 중 80 ∼ 95 %를 다양한 실내 공간에서 생활하고 있으며 (Wiley et al., 1991), 실내오염원이 존재할 경우 실외대기보다 실내공기의 오염도가 극심하다는 연구결과도 있었다 (Hines et al., 1993). (중략)

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.51-56
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• 2008

이동컴퓨팅과 센서, GPS 기술의 발됨에 따라, 실외뿐만 아니라 실내 공간에서 이동객체의 위치 정보를 이용하는 다양한 응용분야들이 개발되고 있다. 그 중에서 이동 객체의 궤적을 이용하여 분석하는 응용분야들의 경우, 실제의 데이터를 획득하는 것이 불가능 하거나 이용이 제한되어 있어서, 실제의 속성을 반영한 합성 데이터를 이용하고 있다. 그러나 대부분의 이동 객체 궤적 생성치는 실내 공간에서 이동하는 객체의 특성을 잘 반영하지 못한다. 이에, 본 논문에서는 실내 공간에서 이동하는 객체의 특성을 살펴보고, 이를 반영한 실내 공간 이동 객체의 궤적 생성기를 구현한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.70-76
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• 2012

The purpose of this study is to analyze of the operating characteristics of the Gas engine driven Heat Pump(GHP) and to reduce maintenance costs through the most Economical plan. As the zoning modifications that have economic effects were confirmed. Applications should be made with a similar purpose of the space. The combination of a modified space has led to reduced operating hours of the outdoor unit. The reduction of the outdoor unit operating hours, reducing maintenance costs accordingly. When analyzed at six years have elapsed, the amount of savings through zoning modifications is more than an additional construction cost. During the design phase, cost-effective operation of the GHP is required for the proper zoning plan.

• Journal of Korea Multimedia Society
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• v.23 no.8
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• pp.1006-1018
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• 2020

Dataset is getting more import to develop a learning based algorithm. Quality of the algorithm definitely depends on dataset. So we introduce new dataset over 200 thousands images which are fully labeled multi modal sensor data. Proposed dataset was designed and constructed for researchers who want to develop detection, tracking, and action classification in outdoor environment for surveillance scenarios. The dataset includes various images and multi modal sensor data under different weather and lighting condition. Therefor, we hope it will be very helpful to develop more robust algorithm for systems equipped with difference kinds of sensors in outdoor application. Case studies with the proposed dataset are also discussed in this paper.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.638-641
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• 2008

Computational investigation was conducted to study the effects of the shape parameter of shroud on the performance of the outdoor unit of an air-conditioners. For this study the Design of Experiment(4-factor 3-level) was created and the an automatic program was composed using VBA to reduce the load of pre-process for CFD. The estimated mathematical equation was produced from this analysis and it was found that the gap between fan and shroud affects more heavily than the other parameters. As a result, the composition of the best parameters was verified that its flow rate was increased by 10 percents and sound pressure level was reduced by 1.2 dBA compare with the worst. And finally, a kind of Propeller fan with blades which were attached to the shroud, so-called 'ProBeller Fan' was introduced in this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.577-582
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• 2012

Recently, noise reduction of air-conditioner is one of the important design factors for high quality product. Especially, customer complaints arise due to noise problem of the outdoor unit. After the operation of air-conditioner start, noise level of outdoor unit is increased gradually and sometimes abnormal noise occurs until it reaches steady state condition. The aim of this paper is to investigate the relation between noise of outdoor unit and thermodynamic properties of cycle at transient condition of room air-conditioner. In order to find out the noise characteristics of outdoor unit, noise and vibration measurements are carried out. Also, the thermodynamic properties of compressor and heat exchanger are measured by using temperature and pressure sensors and experimental results are discussed. Finally, we find out the relation between noise and cycle properties at starting of room air-conditioner and the improvement method to reduce noise level is proposed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2008-2013
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• 2016

This paper proposes analysis and suppression method for reactive power vibration of the slave motor caused by back-EMF mismatch between the master and the slave motor and stator resistance during middle-low speed operation. The master and slave motors are parallel connected dual SPMSMs(Surface mounted Permanent Magnet Synchronous Motors) fed by a single inverter. To suppress vibration of reactive power, RPC(Reactive Power Compensator) proposed in this paper analyzes flux-axis current vibration of the slave motor that occurs in middle-low speed operation using a mathematical model of the fan motor. And RPC adds vibration components detected from flux-axis current of the slave motor to flux-axis current of the master motor. The results of experiment conducted verify the efficacy of the proposed method.