• Journal of Energy Engineering
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• v.6 no.2
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• pp.152-161
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• 1997

Blending various coals during the coke making process affects the quality of coke as well as the total energy required for the process. The mathematical model based on Merrick's work developed to predict the effect of blending coals on coke making process. The Crank-Nicholson method was used to solve the model equation to predict temperature distributions, a coking time, and a total energy required during the process. The developed model successfully applied to Kwang-Yang Steel Company's coke oven to validate the model performance. It is hoped that the model can serve as a guidelines on how to blend coals during the process.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.11a
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• pp.122-131
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• 1994

본 연구에서는 저소음 팬 개발을 위해 검증 실험 대체로 전산유체역학을 응용하고 PT 제작기간 단축을 위한 방법을 제시하고자 한다. 팬 내부의 유동장 해석을 통하여 실제의 설계과정 중에 응용하기 위한 가능성을 알아본 결과, 해석으로부터 여러 대상 팬의 상대평가가 유용하다는 결론을 얻게 되었다. 이 때 효율의 상대평가는 팬 익면의 정압상승 검토를 통하여, 그리고 소음의 평가는 난류에너지 k의 분포를 통하여 비교할 수 있음을 알수 있었다. 또한 실제의 PT제작방법에 있어서도 기존에 비해 제작 기간과 비용면에서 유리한 SLA를 이용한 부분합성법을 시도하여, 기존에 사용했던 NC가공을 통한 PT제작 방법에 제작기간 및 비용을 50%이상 절감/감축할 수 있었다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2006.06a
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• pp.737-747
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• 2006

USN(Ubiquitous Sensor Network)는 환경 및 재난 관리, 에너지 관리, 의료 및 건강 서비스, 물류 및 유통관리 등의 다양한 분야에 응용될 수 있는 네트워크이다. USN은 저 전력으로 센싱 기능, 연산 및 네트워크 기능을 수행하는 초소형의 노드들이 한 지역에 분산되어 망을 구성하는데 USN의 노드들은 전력을 추가적으로 공급받지 못하므로 매우 제한된 전력을 이용하여 주어진 임무를 수행하여야 한다. 또한 노드의 고장으로 인해 토폴로지가 변경될 가능성이 크다. 이러한 특성 때문에 기존의 무선 ad hoc 네트워크를 위해 제안된 경로설정 기법들은 USN 환경에 적합하지 않다. 본 논문에서는 USN 노드의 전력 소비를 최소화함으로써 노드 생존시간을 최대화하기 위한 경로실정 기법을 제안하고 성능을 평가하였다.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.231-238
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• 2011

Variable message signs(VMS) in use are being displaying with the LED device as the luminous source, and it is a recent trend to be changed from the Lamp type to the Surface-Mount Devices(SMD) type. The LED device leads to get VMS display brightly and clearly, leading to have visibility and legibility better than the existing VMS. However, the lights which display off the road, the unnecessary energy, might have negative effect on ecosystem. This study developed the way of getting the lights be displayed only to drivers without the unnecessary energy and estimated the energy efficiency of the development by the optical testing. As a result, this study showed that the energy consumption of the developed display device appeared to decrease by about 36.1% compared to the existing device. Also the upward and downward angle of the lights changed from an angle of $24^{\circ}C$ to $0^{\circ}C$and from an angle of $-24^{\circ}C$ to $-11^{\circ}C$, respectively. Therefore, it anticipates that the developed device would benefit highway safety due to an improvement in visibility and legibility compared to the existing VMS and the energy consumption would be less lower than the existing VMS.

• Journal of the HCI Society of Korea
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• v.9 no.2
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• pp.13-21
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• 2014

Jump-rope is a simple and effective exercise, but its intensive exercise load and monotonous pattern make it difficult to perform consistent workout. On the other hand, jumping rope accompanies large amount of kinetic energy which can be converted into electrical energy. In this study, we designed and implemented a self-powered jump-rope which can support the low-power embedded Bluetooth system inside it. The embedded system wirelessly transmits the acceleration data measured during jumping-rope exercise to a smartphone. We also developed a smartphone app which can count the number of jumps and provide real-time feedback with sound and animated graphic effects in a game context. Pilot test using the prototype smart jump-rope verified that it can be useful to motivation for the jump-rope exercise and make the exercise more effective by providing users with precise information about their exercise. We expect that the developed self-powered jump-rope will change the exercise from an intensive physical activity into electricity-generating fun experience combined with smartphone game, which maximize the benefit of the consistent jump-rope exercise.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.11
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• pp.580-591
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• 2017

In accordance with 2015 Paris agreement, each individual country around the world should voluntarily propose not only its (individual) reduction target, but also actively develop and present expansion targets of its scope and concrete reduction goals exceeding the previous ones. Accordingly, it is necessary to prepare a macroscopic, long-range strategy for reducing energy consumption and greenhouse gas emissions, which can cover a single building, town, city and eventually even a province. The purpose of this research is to gather and compile government-acquired data from various sources and (in accordance with contents and specificity), combine building data by stages by using multi-variable matrix and then analyze the significance of combined data for each stage. The first order data presents the probability and the cost effectiveness of energy saving on the scale of a city or a province, based only upon general information, size and power consumption of buildings. The second order data can identify a pattern of energy consumption for a building of a specific purpose and which tends to consume a larger amount of energy during one particular season (than others). Finally, the third order data can derive influential factors (base load, humidity) from the energy consumption pattern of a building, and thus propose an informed and practical energy-saving method to be applied in real time.

• Journal of KIISE
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• v.43 no.3
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• pp.296-303
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• 2016

Mobile real-time systems with limited system resources and a limited power source need to fully utilize the system resources when the workload is heavy and reduce energy consumption when the workload is light. EDZL (Earliest Deadline until Zero Laxity), a multiprocessor real-time scheduling algorithm, can provide high system utilization, but little work has been done aimed at reducing its energy consumption. This paper tackles the problem of DVFS (Dynamic Voltage/Frequency Scaling) in EDZL scheduling. It proposes a technique to compute a uniform speed on full-chip DVFS platforms and individual speeds of tasks on per-core DVFS platforms. This technique, which is based on the EDZL schedulability test, is a simple but effective one for determining the speeds of tasks offline. We also show through simulation that the proposed technique is useful in reducing energy consumption.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.238-239
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• 2010

주거 상업용 건물에 있어 최근 TV, LED 조명, 컴퓨터, IT 기기들과 같은 직류를 사용하는 부하가 점차 증가함에 따라 기존의 교류 배전 기반의 건물 전력구조에서 에너지절감을 위한 하나의 방안으로 직류기반의 건물 배전구조에 대한 도입에 대한 연구가 활발히 이뤄지고 있다. 또한 직류 형태의 전원인 태양광 발전, 연료전지 등의 신재생 에너지와 가정 및 전기자동차용 배터리의 등장은 직류 기반 전력구조가 가지는 강점을 더욱 부각시키고 있다. 직류 배전 시스템은 기존 교류 배전에서 직류부하를 위한 다중의 전력 변환 과정을 최소화함으로서 전원 및 부하에서 소모되는 에너지를 절감하여 전력시장 내 전체적인 탄소배출량 저감에 기여할 수 있을 것으로 고려되어지고 있다. 이는 직류배전 시스템의 에너지 저감 효용성 이외 기존 교류배전 대비 부하단 부품 수의 감소에 따른 신뢰성 향상 및 가격 저감, 무효전력 고려사항의 제거 등 많은 장점을 가지기 때문이다. 본 논문에서는 소용량 건물에 직류배전 구조가 도입될 경우 실현 가능성이 높은 대표적 직류 배전 구조들을 Functional Modeling 기법을 통해 모델링하며, 시뮬레이션을 통해 기존의 교류 배전 건물과 함께 각각의 전력계 구조에 대한 효율 및 장단점들을 정성적으로 비교하고, 구현에 필요한 고려사항들을 제시한다.

• Journal of the Korea Concrete Institute
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• v.24 no.1
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• pp.61-70
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• 2012

Recently, the government has been working feverously to save energy and reduce greenhouse gas emission by enacting Basic Act on Low Carbon Green Growth at the national level. Improving the insulation performance of building exterior and insulator can reduce the energy in the building sector. This study is about developing light-weight foamed concrete insulation panel that can be applied to buildings to save energy and to find the optimal condition for the development of insulation materials that can save energy by enhancing its physical, kinetic and thermal characteristics. Various experimental factors and conditions were considered in the study such as foam agent types (AES=Alcohol Ethoxy Sulfate, AOS=Alpha-Olefin Sulfonate, VS=Vegetable Soap, FP=Fe-Protein), foam agent dilution concentration (1, 3, 5%), and foam percentage (30, 50, 70%). Experiment results indicated that the surface tension of aqueous solution including foam agent, was lower when AOS was used over other foam agents. FP produced relatively stable foams in 3% or more, which produced unstable foams containing high water content and low surface tension when diluted at low concentration. Depending on foam agent types, compressive strength and thermal conductivity were similar at low density range but showed some differences at high concentration range. In addition, when concentrations of foam agent and foaming ratio increased, pore size increased and open pores are formed. In all types of foam agent, thermal conductivity were excellent, satisfying KS standards. The most outstanding performance for insulation panel was obtained when FP 3% was used.

• Asian Journal of Turfgrass Science
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• v.18 no.1
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• pp.47-53
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• 2004

환경친화적 개발 가능성에 있어서 쓰레기 매립지 골프장 건설은 골프장 이미지 개선, 부지 매입가격 절감, 메탄 에너지 재활용, 국토 이용률 상승, 녹지공간의 확보, 기술 경쟁력 확보 등의 매우 많은 이점을 가지고 있다. 이러한 이점을 개발하기 위해 본 연구에서는, 국내의 쓰레기 매립지 골프장 개발 가능요인과 쓰레기 매립지 현황을 조사하였다. 조사 결과 이용가능성이 있는 매립지는 5%내외이며, 골프장과 같이 녹지를 제공하는 시설의 설치가 미흡한 것으로 나타났다. 이와 함께 이미 개발된 미국의 쓰레기 매립지 골프장 시공 사례를 알아보고, 쓰레기 매립지 골프장 개발의 적극적인 도입을 위해 매립지 토지이용절차와 이용시 판단기준, 토지활용시 고려사항 등을 연구하였다. 이러한 기초자료를 바탕으로 미래의 쓰레기 매립지 활용에 있어 골프장 부지로 사용하고, 건설할 수 있는 타당성과 구체적인 대안을 제시하였다.