• Journal of Power System Engineering
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• v.12 no.3
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• pp.5-11
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• 2008

산업공정에서 널리 사용하는 반응기는 성질이 상이한 물질을 혼합하는 시스템으로서 본 연구에서는 이젝터(ejector)에 의한 반응기의 개발을 수행하였다. 액체-가스 이젝터는 구동유체에 의하여 기체가 흡입되면서 각종 유해가스를 제거하는 목적 또는 기체와 액체의 혼합 등 목적으로 사용된다. 본 실험에서 액체구동 가스혼합반응기의 실험 장치를 구축하고 이젝터 내부의 유동패턴과 기체용해도 자료를 도출하며 고효율 이젝터 설계를 위한 진공도 측정과 디퓨저 각도가 다른 이젝터의 실험 및 수치해석을 수행하였다. 이젝터의 성능은 흡입 측에서의 진공압력으로 평가되며 이 진공압력은 이젝터의 노즐 설계 및 유동조건에 의하여 결정되므로 이에 대한 기본적인 특성 도출이 선결되어야 한다. 순환유체의 유량이 70LPM, 80LPM 90LPM조건에서 두 가지 디퓨저에 대하여 비교실험을 수행하였다. 실험적 연구와 수치해석연구를 통하여 혼합성능과 이젝터의 내부유동특성에 대하여 고찰한 결과 디퓨저의 각도가 5.0도일 때 진공도가 더욱 높으며 구동액체의 유량이 작을 때는 진공도차이가 크지만 유량이 증가함에 따라 진공도 차이가 감소된다. 구동액체의 유량이 증가할수록 용존산소농도는 증가하며 디퓨저의 각도가 5.0도일 때는 용존산소 농도가 더 높게 나타나는 것을 확인할 수 있었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.15-23
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• 2013

Weight reduction of a automobile has been steadily tried in automotive industry to improve fuel efficiency, driving performance and the production profits. Since the weight of BIW takes up a large portion of the total weight of the automobile, reducing the weight of BIW greatly contributes to reducing the total weight of the vehicle. To reduce weight, vehicle manufacturers have tried to apply lightweight materials, such as aluminum and high-strength steel, to the components of BIW instead of conventional steel. In this research, material arrangement of an automotive BIW was optimized by formulating a design problem to minimize weight of the BIW while satisfying design requirements about bending and torsional stiffness and perform a metamodel-based design optimization strategy. As a result of the design optimization, weight of the BIW is reduced by 45.7% while satisfying all design requirements.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.100-103
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• 2016

This Study is focused on hedonic model study for retargeting advertising Based air inteface using useful information. many research related to the existing Internet of things, relatively not many study for effective advertising model based air inteface. So, this study is designed more information, fun, interactive advertising model based air inteface. therefore, result of this study show that implication to produce advertising based air inteface provides a practical guide.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1524-1534
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• 2009

In recent, diagnosing and monitoring technology via in vivo information has been evolved rapidly in worldwide with such capsule-kinds means of incorporating an RFID tag as wireless communication tool. Thus circumstance is pressing local body in Korea to research and develop ingestible RFID capsule which has more miniaturized form, less low power, harmless. This paper focused to investigate new technology and patents, R&D information for adopting proper frequency and designing wireless ingestible capsule antenna system, and suggested practical assignments to implement local R&D. Descriptions are consist of introduction, technology outline, tendency for R&D, patent, market, conclusion and suggestion.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.1020-1027
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• 2003

A traditional mold design has been conducted by an experience-based trial and error, whereby the mold designer would decide the gate locations and processing conditions based on the caring characteristics and its functional requirements. The paper suggests an optimal gate location and processing conditions in the injection molding using a global search method referred to as micro genetic algorithm( ${\mu}$ GA). ${\mu}$ GA yields the optimal solution with a small size of population without respect to design variables for saving time that is needed to calculate the fitness of many individuals. Due to the reason, the paper uses a commercial analysis package of injection molding(CAPA) to analysis a state of flux. In addition to that, axiomatic approach .is applied in the beginning of design. It is a useful method to draw a well-organized and reasonable idea to handle a problem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.659-662
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• 2008

최근 모바일 단말의 종류가 크게 증가하고 있으며, 그 기능과 성능이 크게 향상되고 있다. 또한 이동통신 기술의 발전으로 통신 방식이 다양해지고 있으며 속도도 크게 개선되고 있어 모바일 단말을 통한 인터넷 서비스의 활용에 대한 요구가 크게 증가하고 있다. 이러한 상황의 변화는 모바일 단말의 기능이 통신 기능보다는 서비스 기능을 강화하는 방향으로 진화하게 만들었으며, 이는 실제로 모바일 단말 제조사들이 구글 폰, 야후 폰 등 기존의 인터넷 서비스와 긴밀하게 통합된 기능을 제공하는 제품을 제품화하고 있다. 최근 국내 및 국외의 주요 인터넷 서비스 업체들은 자신들의 서비스를 플랫폼화하여 서비스를 제공하고 있다. 특히 구글, 야후, 아마존, 이베이 등 국외의 주요 업체들은 자신들의 서비스 플랫폼에 대한 개방형 API(Open API)를 공개하여 다양한 클라이언트 응용들이 자신의 서비스를 쉽게 활용할 수 있도록 환경을 구축하고 있으며 이를 기반으로 응용 개발자들을 전폭적으로 지원하고 있다. 이러한 상황에서 모바일 서비스 환경도 사용자들이 유선상에서 사용하던 다양한 인터넷 서비스를 모바일 환경에서 사용하고자 하는 요구가 크게 증가하고 있다. 이는 모바일 단말 시장에서 중요한 요구사항으로 인식되어 향후 모바일 플랫폼들은 편리한 인터넷 서비스와의 연동 기능을 지원할 것으로 예상된다. 본 논문에서는 모바일 단말을 위한 차세대 모바일 웹 플랫폼에 대한 요구사항을 정리해보고, 이를 위한 플랫폼을 설계하여 제안한다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1285-1299
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• 1998

Thousands of multimedia services are being developed over existing public networks and high-speed communication networks. In the multi-carrier network, seamless integration of terminals and services is essential in order to offer an end-to-end and user-independent service. In this paper, we propose the concept of the Interworking Broker to provide an infrastructure for building multimedia service interworking platform that supports interactive multimedia applications in distributed heterogeneous network environment. We describe main techniques developed to achieve the service interworking, and also the functional architecture of the Interworking Broker in heterogeneous ATM network environments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1086-1092
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• 2002

Computer simulation is essential to design the suspension elements of railway vehicle. By computer simulation, engineers can assess the feasibility of a given design factors and change them to get a better design. But if one wishes to perform complex analysis on the simulation, such as railway vehicle dynamic, the computational time can become overwhelming. Therefore, many researchers have used a mega model that has a regression model made by sampling data through simulation. In this paper, the neural network is used a mega model that have twenty-nine design variables and forty-six responses. After this mega model is constructed, multi-objective optimal solutions are achieved by using the differential evolution. This paper shows that this optimization method using the neural network and the differential evolution is a very efficient tool to solve the complex optimization problem.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.80-87
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• 2004

Active control of on-orbit spacecraft jitter is a significant problem for future spacecraft mission requiring stringent pointing performance. Jitter is major disturbance source degrading payload pointing performance. Both passive and active jitter isolation techniques have been studied during the last decade. We present active jitter isolation for a model device in this work. The device provides active control capability by 3 degree-of-freedom control of payload in feedback control strategy. Mathematical modeling of the device is pursued which is naturally used for a baseline controller design. Simulation results are used to validate the designed control law.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.69-75
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• 2005

Recently it was reported that the vibration problems on the oil pipe support structure of the crude oil carrier were occurred. in order to investigate the vibration characteristics and the causes of the vibration occasionally. the vibration measurements and impact tests for the oil Pipe structure were carried out. From the measurement results severe vibration was caused by the resonance between the transversal natural frequency of the structure and $6^{th}$ order excitation force of the main engine. Providing the proper countermeasures a series of the vibration analyses were carried out based on the measurement results. From the analysis results, it was concluded that the vibration characteristics of the oil pipe structure were affected by the oil pipes, support structure itself, upper deck structure and the installation spaces and the standard design was established for the crude oil carriers.