• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.41-44
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• 2003

본 논문에서는 부하의 상태에 따라 능동적으로 추종 및 보상기능을 갖으며, 에너지절약기능 및 고품질을 유지할 수 있는 소형이면서 가격도 저렴한 전력 품질보상장치의 Prototype을 구성하고져 한다. 최근 일반 주택이나 사무실내에 반도체소자 및 전력전자기기의 사용이 급증하면서 이들 기기에서 발생하는 고조파 및 무효전력량이 증가하여 주위의 환경과 전기적 손실이 심각한 문제를 발생한다. 이런 상황 하에서 전력품질에 민감한 부하들이 급증하고 부하의 민감도에 따라 다양한 전력품질을 요구하는 장치가 점점 필요로 하게 되었다. 지금까지 국내 외적으로 이런 문제를 보상하는 소형보상장치는 가전기기 즉 세탁기 냉장고등 각기 개개로 부착하고 있는 것들은 어느 정도 개발되어 사용되고 있으나, 가정용도로 사용하기 위하여 주택전체를 보상하는 기기는 개발이 되어있지 않은 상태에 있다. 따라서 현재까지 국내 외적으로 개발되어온 기기들은 가정용 소형 전력품질의 모니터링 수준이라고 할 수 있다. 따라서 본 논문에서는 기기의 최 말단 즉, 기기자체에 부착하여 사용하는 단순형 보상형태를 확장시켜 소형이면서 에너지 절약이 가능한 가정용으로 적합한 능동 추종형 전력품질 보상장치의 기술에 대한 연구를 하는 것이 목적이다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.9
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• pp.1-11
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• 2002

The optimal AP placement for wireless LAN is important factor for improving service quality and reducing cost. Decision of AP placement is depend on radio signal strength, environment factor and logical area property, which is user's frequently posed place. This paper proposes optimal multiple AP placement method based on radio prediction tool. The proposed method can get flexibility in multiple AP placement using user defined parameter and the optimization design uses Hopfield network algorithm. And path-loss model is used for one of radion prediction model. The result of simulation shows that it is efficiently reduces the process to find optimal AP placement. And the proposed optimization design of multiple AP placement can improve service quality for wireless LAN.

• KIEAE Journal
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• v.17 no.5
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• pp.25-31
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• 2017

Purpose: Currently, there are many success stories coming out various energy-saving / production or eco-friendly buildings. However, these case and method didn't consider of application with existing housing and high-rise housings. In the case of Europe, the North America is gradually grew and settle through the voluntary, small, private development. But this method and system are not fit for the majority of developing countries including South Korea. Method: In this situation, this paper analyse, first arranged previous research and case study, second divided factors and re-organized factors, third analysed plan and elevation of apartment and selected main plan type and elevation type of apartment, finally analysed method of application with existing buildings and high-rise buildings by test and simulation. Result: In sum, this research finally analyzed the change of electricity and fuel consumption according to the change of insulation standard. This study has been expected to serve as a bridge of the energy housing system development and suggest new method applied to the existing housing and building.

• Journal of Bio-Environment Control
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• v.9 no.2
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• pp.120-126
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• 2000

The quality of oak mushoom(Lentinus edodes(Berk) Sing) is sensitively affected by environmental factors, especially moisture by the rain during the growing period. To protect mushrooms from being wet, plastic-covered facilities with side openings are mostly being used. However, the indoor temperature and humidity f the facility without roof opening become higher due to its poor ventilation, and consequently reduce the productivity and quality as well. In this study, we analyzed the ventilation rates and indoor temperatures of improved facilities as affected by the area of roof opening and shading rate by the model. The indoor temperature decreased by more than 2.5$^{\circ}C$ as the shading rate increased from 50% to 90%, and especially the effect of wind speed on indoor temperature was significantly great under as low as 50% of shading rate. The ventilation rate became higher under wind speed of 1~2m.s-1 regardless of the shading rate. As the wind speed increased from 0m.s-1 to 2m.s-1, the indoor temperature decreased by more than 2.$0^{\circ}C$. Moreover, the indoor temperature became lower with increasing roof opening ratio, but showed no significant differences at more than 50% of roof opening ratio. At lower shading rate, the indoor temperature sensitively decreased with increasing area of roof opening. Additionally, we obtained the higher ventilation performance with the area of roof opening more or less equal to side opening, regardless of the wind speed and shading rate.

• Journal of KIISE
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• v.44 no.7
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• pp.733-741
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• 2017

LPWAN(Low Power Wide Area Network) technology is M2M (Machine to Machine) networking technology for the Internet of Things. The technology is designed to support low-power, long-distance and low-speed communications that are typical of LoRaWAN(Long Range Wide Area Network). To exchange inter-object information using a LoRaWAN, the link performances for various environments must be known. however, active performance analysis research that is based on an empirical environment is nonexistent. Therefore, this paper empirically evaluates the performance of the LoRa (Long Range) link, a physical communication technology of the LoRaWAN for various variables that may affect the link quality in indoor and outdoor environments. To achieve this, a physical performance monitoring system was designed and implemented. A communication experiment environment was subsequently constructed based on the indoor and outdoor conditions. The SNR(Signal to Noise Ratio), RSSI(Received Signal Strength Indication), and the PDR(Packet Delivery Ratio) were evaluated.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.67-73
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• 2019

In this study, to optimize the production and utilization of biogas for organic waste resources, the precision monitoring of on-site facilities and the energy balance by facility were analyzed, and the solutions for field problems were investigated, and the design and operation guidelines for pretreatment facilities and generators were presented. Gas pre-treatment is required to solve frequent failures and efficiency degradation in operation of high quality refining facilities, and processing processes such as desulfurization, dehumidification, deoxidization, dust treatment, volatile organic compounds, etc. Since these processes are substances that are also eliminated from the high-quality process, quantitative guidelines are not presented in the gas pretreatment process, but are suggested to operate during the processing process as a qualitative guideline. In particular, dust, siloxane, and volatile organic compounds are the main cause of frequent failure of high-quality processes if they are not removed from the gas pretreatment process. Design of the biogas high-quality process. The operation guidelines provide quality standards [Methane content (including propane) of 95% or more] with 90% or more utilization of the total gas generation, two systems, and a margin of 10% or more. It also proposed installing gas equalization tank, installing thermal automatic control system for controlling equalization of auxiliary fuel, installing dehumidification device at the back of high quality for removing moisture generated in the process of gas compression, installing heat-resisting facilities to prevent freezing of facilities in winter and reducing efficiency, and installing membrane facilities in particular.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.209-214
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• 2002

냉방과 습기제거에 제습제를 이용하는 것은 효과적이고, 경제적이며 환경 친화적인 방법이다. 제습제를 사용한 공기조화시스템은 학교, 극장, 슈퍼마켓, 병원과 음식점 등 모든 건물에 신선한 공기를 제공함으로써 실내공기의 품질을 향상시킨다. 수분을 포함하는 다량의 공기를 제습하기 위해서는 제습제와 공기의 접촉을 늘려주어야 하고, 이를 위하여 허니컴 형태의 제습제를 사용하는 것이 바람직하다.(중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.249-254
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• 2002

온실에서 환기는 외기와의 공기교환을 통한 온도 및 습도의 조절뿐만 아니라 이산화탄소 등의 가스농도를 조절함으로써 온실내 공기의 쾌적성 확보와 실내기류의 형성으로 인한 작물의 생육촉진에도 중요한 역할을 담당한다. 그러므로, 작물생육환경의 최적화를 통한 품질향상 및 수확량 증대를 목적으로 하는 온실재배에 있어서 환기특성 분석 및 공기유동 예측은 가장 기본적인 설계요소라 할 수 있다. (중략)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.8
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• pp.663-673
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• 2013

The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalization of LBS is the accurate estimating position for mobile object. Focusing on IMU deployed in smart phone, we develop a hybrid positioning estimation framework with a combination of WPS. The developed approaches can strengthen the advantages of independent indoor applicability of IMU. The estimation of IMU is efficiently compensated by radio fingerprint based Wi-Fi Positioning System. We put a focus especially on the hybrid algorithmic framework. Compared on the existing approaches of WPS or IMU, we achieve the comparable higher performance on both of average error of estimation and deviation of errors. Furthermore test-bed based on smart phone platform is practically developed and all data have been harvested from the actual measurement of test indoor area. This can approve the practical usefulness of proposed framework.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.852-857
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• 2010

In this paper, we proposed and demonstrated an indoor visible-light communication system using an array of light-emitting diodes (LEDs). The main idea is based on that the LEDs can be used not only for lighting but also for free-space optical communications. Because LEDs offer advantageous properties such as high brightness, reliability, lower power consumption and long lifetime, the indoor visible-light communication systems are going to provide high quality of service by the high radiation power of the LED lighting. Prototype of simplex channel for audio and the full-duplex channel for text message were developed. Results indicates the viability of creating inexpensive free-space optical communication transceivers that might be embedded in commercial light products to supports indoor wireless networking.