• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.65-72
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• 2006

Heat transfer augmentation in heat exchangers has received much attention in recent years, mainly due to energy efficiency and environmental considerations. Many active and Passive techniques are currently being employed in heat exchangers, with some inserts providing a cost-effective and efficient means of augmenting heat transfer. The Purpose of this paper is to determine the pressure loss and heat transfer characteristics of a heat exchanger using static mixing technology. Experimental measurements were taken on two set-ups: a single tube heat exchanger and a shell-tube heat exchanger with two static mixing inserts. It was concluded that the static mixing inserts resulted in an increase in the pressure loss and heat transfer characteristics as can be expected.

• Review of KIISC
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• v.27 no.3
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• pp.12-19
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• 2017

기하급수적으로 증가하고 있는 변종 악성코드에 대응하기 위한 식별 연구가 다양화 되고 있다. 최근 연구에서는 기존 악성코드 분석 기술 (정적/동적)의 개별 사용 한계를 파악하고, 각 방식을 혼합한 하이브리드 분석으로 전환하는 추세이다. 나아가 변종 식별이 어려운 악성코드를 더욱 정확하게 식별하기 위해 기계 학습을 적용하기에 이르렀다. 이에 따라, 본 논문에서는 변종 악성코드 식별을 위해 각 연구에서 활용한 기계 학습 기술과 사용한 악성코드 특징을 중심으로 변종 악성코드 식별 연구를 분류 및 분석한다.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1948-1952
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• 2007

Heat transfer augmentation based on the process intensification concept in heat exchangers and thermal reactors has received much attention in recent years, mainly due to energy efficiency and environmental considerations. The concept consists of the development of novel apparatuses and techniques that, compared to those commonly used today, are expected to bring dramatic improvements in manufacturing and processing, substantially decreasing equipment size, energy consumption, and ultimately resulting in cheaper, sustainable technologies. The objective of this paper was to investigate the heat transfer characteristics of tubular thermal reactor using static mixing technology. Glycerin and water were used as the test fluids and water was used as the heating source. The results for heat transfer rate were strongly influenced by tube geometry and flow conditions.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.646-648
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• 2004

사용자의 실영상을 가상세계에 합성하여 보여주는 형태의 혼합현실(mixed reality) 기술에서 입력영상으로부터의 사용자 추출은 필수적인 단계이다 본 연구에서는 물체로부터 반사되는 적외선 점보를 이용하는 능동 적외선(Active Infrared) 기반 동적배경 제거 기법을 제안한다 이 기법에서는 대형 디스플레이 환경 내에 설치된 적외선 광원 및 적외선 투과 필터를 장착한 흑백카메라를 이용하여 획득된 적외선 반사 영상에 배경 제거 알고리즘을 적용함으로써 사용자 영역을 추출한다. 제안 기법을 이용하면 CAVE$^{TH}$ -like 시스템과 같이 정적배경을 보장하지 못하는 환경에서도 고가의 장비 없이 빠르고 정확하게 사용자를 추출할 수 있기 때문에 프로젝션 환경 내에 존재하는 사용자를 가상세계와 함께 합성하여 보여줄 수 있다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.4
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• pp.65-71
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• 2009

Web Contents have been evolved from statics, dynamics contents to Mashup service. In recent years, Mashup which can creates new contents by mixing different services is topic on the web service. But, Mashup is only concentrate on making new contents to provide for client. In this paper, we propose the policy of composing services and client-friendly UI.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.328-340
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• 1991

The combustion process in the combustion chamber has been investigated by taking pressure, temperature, chemical equilibrium and the shape of flame. To predict temperature of a flame in a combustion chamber is one of very important problems in the field of combustion and the temperature is a important factor of ignition and counteraction to inflammation. In this paper, the flame temperature was determined by the method of the Rayleigh scattering of Ar-Ion Laser (514.5nm). The Rayleigh scattering has been got considerably attention because of its strong cattering intensity. As a result, it is shown that I can measure the shape of flame by schlieren photography and that I can get the flame temperature variation in constant volume combustion chamber by Laser Rayleigh Scattering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.345-350
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• 2017

Downsizing is widely applied to diesel engines in order to improve fuel efficiency and reduce exhaust emissions. Engine sizes are becoming smaller but pressure and temperature inside combustion chambers are increasing. Therefore, research for fuel spray under high pressure and temperature conditions is important. A constant volume chamber which simulates high temperature and pressure likely to be found in diesel engines was developed in this study. Pressure and temperature were increased abruptly because of ignition of the pre-mixture in the constant volume chamber. Then pressure and temperature were gradually decreased due to the heat loss through the chamber wall. Fuel spray occurred when temperature and pressure were reached at the target condition. In this experiment, the temperature condition should be exactly defined to understand the relation between fuel evaporation and ambient temperature. A fast response thermocouple was developed and used to measure the temporal and spatial temperature distribution during the combustion process inside the combustion chamber. In the results, the core temperature was slightly higher than the bulk temperature calculated by the gas equation. Ed-note: do you want to say 'ideal gas equation'? This was attributed to the heat transfer loss through the chamber wall. The vertical temperature deviation was higher than the horizontal temperature deviation by 5% which resulted from the buoyancy effect.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.281-290
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• 2009

In this study, an analysis technique of hybrid girder considering nonlinearity of steel-concrete contact surface is presented. Steel-concrete hybrid girder shows partial-interaction behavior due to the deformation of shear connectors, slip and detachment at the interface, and cracks under the applied loads. Therefore, the partial-interaction approach becomes more reasonable. Contact surface is modeled by interface element and analyzed nonlinearly because of cost of time and effort to detailed model and analysis. Steel and Concrete are modeled considering non-linearity of materials. Material property of contact surface is obtained from push-out test and input to interface element. For the constitutive models, Drucker-Prager and smeared cracking model are used for concrete in compression and tension, respectively, and a von-Mises model is used for steel. This analysis technique is verified by comparing it with test results. Using verified analysis technique, various analyses are performed with different parameters such as nonlinear material property of interface element and prestress. The results are compared with linear analysis result and analysis result with the assumption of full-interaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2054-2060
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• 2011

The purpose of this paper is to investigate spray characteristics of GDI injector that is economic and environment-friendly. Injector characteristics such as penetration length, spray angle and mixture formation were measured using experimental visualization technique. Especially, it has been analyzed that the influences of ambient pressure and injection pressure on penetration length and spray angle. To visualize the spray, a constant volume combustion chamber and fuel supply system have been manufactured. A high-speed camera and LED light source have been applied to obtain spray images. The experimental and visualization result shows that the penetration length is increased as decreasing ambient pressure and/or increasing injection pressure. Also, ambient pressure and injection pressure have minor effect on the spray angle variation.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.1272-1275
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• 2011

네이버, 다음, 구글 등의 웹 상에서 제공하는 지도 서비스와 KML, GML, GeoRSS와 같은 기술들을 이용하여 하나의 위치 정보로 통합한 지리정보를 사용자에게 제공해 줄 수 있는 연구들은 현재까지 활발히 진행되어 왔다. 그러나 이러한 연구들은 위치 정보만 통하여 줄 뿐 의미 정보까지 통합하여 사용자들에게 다양한 정보들을 제공해주지 못한다. 이 논문에서는 KML, GML, GeoRSS 등으로 표현된 풍부한 지리정보들을 통합하여 웹 기반 지도 서비스에 제공해주는 시스템을 제안한다. 또한 지리정보들의 스키마 통합을 위해 어댑터 기반 의미 처리 방법과 정적/동적 의미 관리 기반 접근 방법을 혼합한 하이브리드 스키마 매칭(Hybrid Schema Matching, HSM) 방법을 제안하고, 제안 시스템의 평가를 위해 스키마 매칭을 위한 4가지 접근 방법과 비교 평가를 수행한다. 평가의 결과로 제안 시스템은 의미 해석에 대한 신뢰성이 보장되고 시스템 구축 비용과 데이터 통합 비용이 상대적으로 낮다는 특징을 지닌다.