• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.486-494
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• 2014

Intelligent homes consist of ubiquitous sensors, home networks, and a context-aware computing system. These homes are expected to offer many services such as intelligent air-conditioning, lighting control, health monitoring, and home security. In order to realize these services, many researchers have worked on various research topics including smart sensors with low power consumption, home network protocols, resident and location detection, context-awareness, and scenario and service control. This paper presents the real-time metabolic rate estimation method that is based on measured heart rate for human adaptive appliance (air-conditioner, lighting etc.). This estimation results can provide valuable information to control smart appliances so that they can adjust themselves according to the status of residents. The heart rate based method has been experimentally compared with the location-based method on a test bed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.24-29
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• 2003

Deep sea water has cold temperature, abundant nutrients and minerals, and good water quality that is pathogen-free and stable. Compared with surface water, deep sea water contains more nutrition salt, such as nitrogen and phosphor. Moreover, if has the good balance of minerals. Because of the ability of the spray drying process to produce a free-flowing power considering of spherical particles with a well-defined size distribution and the rapid drying times for heat-sensitive material, spray drying is attractive for a wide range of applications spray drying is a unique unit operation in which powders are produced from a liquid feed in a single processing step. Key component of the process are atomizer, spray chamber. Design of spray chamber should be based on the atomizer type, the production rate, and the particle size required. Because of the complex processes taking place during spray drying, traditional design method are based on pilot-plant tests and empirical scale-up rules. Modern technique such as CFD have a role to play in design and troubleshooting.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.151-164
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• 2005

태양전지는 요구전력의 필요에 따라 직 병렬로 연결하여 태양전지 모듈(solar cell module)로 제품화한다. 태양전지가 실제로 전자제품에 연결해서 사용하기 위해서는 주변장치(BOS, Balance of System)가 사용된다. 또한 일사량의 강도에 따라 불균일한 직류전기가 발생되므로, 태양광발전시스템은 모듈을 직 병렬로 연결한 태양전지 어레이(solar cell array)와 안정된 전기공급을 위한 전력조정기(power conditioning system, 이하 PCS)가 필요하다. 또한 직류가 아닌 교류를 필요로 하는 응용제품에는 직 교류변환장치 인버터(inverter)를 필요로 한다. 본 과제는 전시를 위한 연구개발 목적보다는 태양광 시스템 보급 양산기술에 중심을 두어 태양광 산업경제를 활성화 하고자한다. 따라서 본 과제는 기존에 연구개발과 특수목적 시장 중심인 초고효율 태양전지 개발보다 경제적인 기여도와 파급효과가 크다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.515-524
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• 2010

Recently, many actions are taking to accelerate progress toward social consensus and implementation of Smart Grid. Smart Grid refers to a evolution of the electricity supply infrastructure that monitors, protects, and intelligently optimize the operation of the interconnected elements including various type of generators, power grid, building/home automation system and end-use consumers. The most distinguished element will be Advanced Metering Infrastructure (AMI) that will be installed to every end-use consumer's home or building and optimize the energy consumption of the end-use consumer. The key function of AMI is energy management capability that coordinates and optimally controls the various loads according to the operating condition and environments. In this study, we figure out the basic function of AMI in Smart Energy House that can be defined as a model house implementing in Smart Grid. This paper proposes the energy management algorithm that will be implemented in AMI at Smart Energy House. The paper also show how energy saving in Smart Energy House can be achieved applying the proposed algorithm to an actual house model that has mainly lighting, air-conditioning, TV loads.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1150-1158
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• 2010

In this paper, a new reliable portable activity monitoring device implemented with the buddhist-style bowing activity and walking step detection algorithm, is presented. In order to monitor the bowing and walking activities, miniaturized 3-axis accelerometer sensor with the sensitivity of 800 mV/g was used. After initial signal conditioning, vector magnitude of accelerometer signals was calculated. Syntactic peak detection method was used in order to feature points. All signal processing algorithms were implemented in ultra-low power microcontroller MSP430 with double precision floating point arithmetic. For evaluation, 19 young man($24.22\pm5.22$ yrs) and woman($22.28\pm2.72$ yrs) were involved. The accuracy of the proposed algorithms were 98.91 %($\pm0.011$) for walking step detection and 98.25 %($\pm0.023$) for buddhist-style bowing activity. Comparing to the commercialized pedometer accuracy, 87.1 %($\pm0.058$), the proposed walking step detection algorithms show more reliable accuracy.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.408-421
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• 2008

In this paper, the parallel operation for a FC generation system is introduced and designed in order to increase the capacity for the distributed generation of a proton exchange membrane fuel cell (PEMFC) system. The equipment is the type that is used by parallel operated PEMFC generation systems which have two PEMFC systems, two dc/dc boost converters with shared dc link, and a grid-connected dc/ac inverter for embedded generation. The system requirement for the purpose of parallel operated generation using PEMFC system is also described. Aspects related to the mechanical (MBOP) and electrical (EBOP) component, size, and system complexity of the distributed generation system, it is explained in order to design an optimal distributed generation system using PEMFC. The optimal controller design for the parallel operation of the converter is suggested and informative simulations and experimental results are provided.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.992-996
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• 2004

Small electric motors in an automobile perform various tasks such as engine cooling, pumping, and in heating, ventilating, and air-conditioning (HVAC) system. At present, most of dc motors are supplied by 12V or 24V batteries. However, DC motors surfer from lack of efficiency, low life cycles and unreliability. Therefore, there is a growing interest in substituting DC motors for advanced AC motors including switched reluctance motors. Although there are several other forms SRM converters, they are either unsatisfactory to the control performance or unsuitable for the 12V-battery powered 3-phase SRM drives. Taking into account the requirement for effective operation and simplicity structure of converter in the limited internal environment of automobiles, the author inclines toward selecting the modified C-dump converter as well as the energy efficient C-dump converter. This is so that more economical and efficient converter topology in automobile industries can be utilized. This paper describes the foundation for the design and development of a 12V-250W-3000rpm SRM drives for automobiles. Furthermore, complete circuit, computer simulation and experiment results are presented to verify the performance of the C-dump converters.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.613-619
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• 2007

This study has carried out a performance of dimensionally stable anode for the purpose of disinfection of Legionella pneumophila in water. Three kinds of electrode were prepared by plating and thermal deposition, which were coated by the oxides of Pt, Ru and Ir on Ti metal surface, respectively. The order of disinfection performance for Legionella pneumophila was Ru/Ti > Ir/Ti > Pt/Ti. Free Cl and $ClO_2$ generation of Ir/Ti electrode was higher than that of two electrodes. However, the concentrations of generated $H_2O_2$ and $O_3$ of the Ru/Ti electrode were highest among the three electrodes. The higher NaCl concentration was, the more oxidants was generated and disinfection effect was increased. However, optimum NaCl dosage was 0.0125% due to the regulation on the conductivity and $Cl^-$ concentration for the cooling water quality of air conditioning and refrigeration equipment. With the increase of current, oxidants was more generated and following disinfection effect was increased. The increase of electrode distance reduced oxidants generation due to the low electric power, and their disinfection effect was decreased accordingly.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.4
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• pp.46-54
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• 2019

In this study, the performance of a shell and tube heat exchanger (STHE) and welded plate heat exchanger (WPHE) was measured experimentally. The pass numbers of the STHE was changed by 1, 2 and 4. As a result, the WPHE showed 2.1 times higher heat exchange capacity than that of the STHE. In case of pressure drop, the STHE with 1 and 2 pass number has a lower pressure drop than the WPHE, while the STHE with 4 pass presented higher pressure drop than the WPHE. The performance index considering the heat exchange capacity and pump consumption power, showed in oder of STHE_Pass1 > STHE_Pass2 > W PHE > STHE_Pass4 under the same flow rate. Therefore, when the WPHE was designed optimally under same operating condition with STHE, the maintenance fee and space can be reduced effectively by using the WPHE.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.691-697
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• 2008

Heat exchangers are commonly used in practice in a wide range of application, from heat and air-conditioning system in a household, to chemical processing and power production in large plant. An Experimental study was conducted to investigated the fluid flow and heat transfer around four circular cylinders of in-line in a cross flow of air. The local and average heat transfer characteristics for tube banks are investigated in the present study. Heat transfer in a heat exchanger usually involves convection in each fluid and conduction through the wall separating the two fluid. The in-line pitch ratio was in the range $1.5{\leq}L/d{\leq}4.0$, where L is the center distance and d the cylinder diameter, and in the Reynolds number $8,000{\leq}Re{\leq}50,000$. The local and mean Nusselt numbers were estimated. Subsequently, the heat transfer characteristics of four circular cylinders are found to exhibit a strong dependency upon the separation point of their upstream cylinders.