• International Journal of Advanced Culture Technology
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• v.3 no.2
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• pp.124-131
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• 2015

Computational fluid dynamics (CFD) has been employed for the Heat exchanger efficiency of a counter flow heat exchanger. The Heat exchanger efficiency has been assessed by considering the computed Nusselt number and flow friction characteristics in the double pipes heat exchanger equipped with two types twisted-tapes: (1) single clockwise direction and (2) alternate clockwise and counterclockwise direction. Cold and hot water are used as working fluids in shell and tube side, respectively. Hot and cold water inlet mass flow rates ranging are between 0.04 and 0.25 kg/s, and 0.166 kg/s, respectively. The inlet hot and cold water temperatures are 54 and $30^{\circ}C$, respectively. The results obtained from the tube with twisted-tapes insert are compared with plain tube. Nusselt number and friction factor obtained by CFD simulations were compared with correlations available in the literature. The numerical results were found in good agreement with the results reported in literature.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.11-17
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• 2007

The amount of incident rays over inclination according to direction has been widely utilized as important data in installing photovoltaic systems. This is because the performance of the photovoltaic systems in much affected by angle and direction of incident rays. Recognizing that factors mentioned above are of importance, actual experiment on the moving route of the sun have been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. After all, the standard for designing highly optimized photovoltaic systems will be provided for designers and employees working in the photovoltaic module related industries.

• Review of Korean Society for Internet Information
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• v.8 no.3
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• pp.49-58
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• 2007

The IPTV Standardization work being done by the ITU-T in collaboration with other SDOs and telecommunication companies. Currently IPTV services are provided with no global standards and interoperability. ITU-T leads the process of IPTV standardization. We used the ITU-Ts working documents which were publically available to investigate the direction of IPTV standardization process. Many things including architecture, services, service requirements, codec and error correction mechanisms etc already defined through recommendations. But still there is effort going on to standardize the complete IPTV system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1699-1701
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• 2010

The Active Noise Cancelling(ANC) headphone is now becoming commercially available. But it reduces not only noise but also information signals such as speech or some signals including audible information in particular situation. In this paper, we propose an ANC headphone using adaptive beam-forming techniques which cancels signals except the headphone wearer's look direction signal. It enables workers working in noisy condition to talk with their coworkers. Computer simulation is performed to show the effectiveness of a proposed algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.43-51
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• 1989

Free jet was investigated experimentally and numerically in range of Reynolds number from 9900 to 21000. The working fluid was air; the mean velocity components and turbulent quantities were measured by a hot-wire anemometer. In numerical computations, the governing partial differential equations of elliptic type were solved with conventional k- ${\epsilon}$ turbulence model. The measurements show that the jet increased linearly in flow direction, and that similarity for each turbulent quantity such as Reynolds shear stress, or turbulent kinetic energy was revealed in the fully developed region. The computational results show good agreements with experiments.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2000.11a
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• pp.35-38
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• 2000

An early step toward evaluating a predicted RNA secondary structure is to visualize the predicted structure in graphical form. This talk will present an algorithm for efficiently drawing RNA secondary structures. The algorithm represents the direction and space for a structural element using vector and vector space, and generates nearly overlap-free polygonal displays. The algorithm and a graphical user interface have been implemented in a working program called VizQFolder on IBM PC compatibles.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2002.08a
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• pp.82-91
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• 2002

방파제에 대한 신뢰성 설계 방법은 유럽과 일본을 중심으로1980년대 중반 이후로 발전되어 왔다. 유럽에서는 van der Meer(1988a)가 방파제 피복재의 설계에 확률론적인 방법을 도입하였고, Burcharth(1991)는 사석방파제에 대하여 부분안전계수(partial safety factor)를 이용한 신뢰성 설계 방법을 제시하였다 최근 Burcharth and Sørensen(1999)은 PIANC (Permanent International Association of Navigation Congress) Working Groups의 결과를 요약하여 사석방파제와 직립방파제에 대한 부분안전계수들을 확립하였다. (중략)

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.37-40
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• 1987

In transverse flux linear induction motors(TFLIM), The loops of the working flux lie in planes transverse to the direction of motion. With a poly-phase primary winding, The TFLIMs has both electro-magnetic propulsion and levitation force. Thus, TFLIM a will be useful in high speed ground transportation systems. In this paper, The characteristics of a single aide TFLIM are analysed by using electromagnetic field theory.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.94-95
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• 2013

Construction safety education plays role to provide necessary skills to workers for working safely. It is also important safety measure be used efficiently without any restriction to construction accident prevention. On this study, to develop effective education contents, we analyzed propriety of education contents used in construction sites, drew problem, and suggested the improvement direction.

• Ceramist
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• v.21 no.1
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• pp.4-11
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• 2018

Display is an essence in human-machine communication interface. As mobile environment such as internet of things (IOT) and Artificial Intelligence (AI) progress, importance of display increases. Here we review research trend in flexible organic light emitting displays (OLEDs). This review article covers all the components consisting of flexible OELDs and shows direction of the recent research. This paper would be helpful for readers and researchers working in this field and provide perspective for future displays.