• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4918-4924
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• 2015

In this paper, we consider the capacity improvement of systems exploiting dual-polarized antennas for two-user transmission. To this end, we analyze the upper bounds of ergodic capacities for multicast and unicast data services in the systems, and propose the condition for adjusting the complex cross-polarization discriminations (XPDs) to maximize the ergodic capacities. In addition, we present the adjustment condition of the complex XPDs that can achieve spectral efficiencies close to the maximum ergodic capacities with lower system complexity. Lastly simulation results demonstrate that the systems using the proposed conditions can obtain higher spectral efficiencies than the ones employing different adjustment conditions including the exiting adjustment condition.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.2
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• pp.336-343
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• 2009

Because ships are very isolated and independent objects when sailing on the ocean, if a fire and smoke occurs, nobody can be sure to escape safely from ship at the moment. On the focus of the relationship between the sight transmissivity by fire smoke density and the life safety, this study performs simulations and experiments, respectively. To evaluate the theoretical evacuation time, CFAST software which is known as a 2 zone model analysis tool is used, and the result is 54 seconds from ECR(Engine Control Room) exit to upper deck exit and 34 seconds from bosun store to upper deck exit. And totally 12 types of experiments are performed with other 10 persons per experiment. As the result, it is cleared that the low sight transmissivity leads to the low life safety and the obstruction which can be happen unexpectedly on the evacuation way on fire makes it worse. At the condition of the smoke density 0%, over 90% people arrive at upper deck exit safely. But with the transmissivity of 8%, 70%(from ECR) and 30%(from bosun store) among experiment persons of each can survive, and with same density and unexpected obstruction, the survival ratio goes down to only 20% and 10%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.452-458
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• 2004

The major cause of compressor failure is the decrease of oil viscosity due to floodback. In most previous researches on the compressor reliability, the relationship between oil circulation rate and performance or oil viscosity has been studied. Another research topic is flow visualization by using a sight glass on the bottom of a compressor sump area and accumulator. Both oil film thickness and oil level through the sight glass should be assessed for compressor reliability if the oil content of the mixture is small and low viscosity raise poor lubrication of pump bearing. In this study, the compressor reliability was assessed by measuring the viscosity of the mixture and calculating oil film thickness. The analysis of the relationship between bottom shell super heat and oil film thickness at heating operation was peformed. It is concluded that bottom shell superheat does not perfectly stand for the mixture's behavior for a low ambient heating operation and oil film thickness can give more detailed and direct criteria for compressor reliability.

• The Journal of Korea CHUNA Manual Medicine
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• v.5 no.1
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• pp.237-242
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• 2004

Objective : The purpose of this report is to examine the effects of Scalp Acupunture therapy in the diplopia by traffic accident. Methods : We investigated one patient suffering from diplopia which was admitted to Kyung-Ju O.M. hospital from April 16, 2004 to May 22, 2004. We treated one patient by Scalp Acupunture therapy. Results : 1. We operated Scalp Acupunture on the sight-area(視區) 2. In the result of treatment, the diplopia is distinguished almost. Conclusions : The scalp acupunture therapy is effective of diplopia patient, but we thought that it needed to prove effects of Scalp Acupunture therapy for efficient application with more clinical cases.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.904-912
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• 2011

In this paper, we have proposed a M&S tool for analyzing detection coverage and target localization in bistatic radar system. The detection coverage determined by radar parameters is meaningful when it satisfies the clear line-of-sight condition. We improved the method to find the minimum altitudes of transmitter and receiver for meeting the condition by considering three-dimensional coverage. Its computational burden is not problematic because the calculation is for maximizing the performance of the radar and does not demand a real-time operation. In addition, target localization on three-dimensional earth model based on the information of the height, longitude, and latitude is proposed instead of the previous unpractical calculation on two-dimensional bistatic plane. Its precalculated result can reduce its computation burden and it is suitable for real-time estimation of target location.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.143-149
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• 2007

We have compared and analyzed the definition of medical devices, classification, who treats, controls and sales the spectacle frames in South Korea, USA and European Union in this paper. South Korea classifies the spectacle frames as an industrial products while EU and USA regards it them as the medical devices. Sunglasses are industrial products in South Korea and EU but they are still the medical devices in USA. Assignment of spectacle frames and sunglasses as an industrial products could bring into several problems. Restricted classification of medical devices on spectacle frames and sunglasses will resolve the problem mentioned.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.24-36
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• 2011

A new approach for spacecraft absolute attitude estimation based on the unscented Kalman filter (UKF) is extended to relative attitude estimation and navigation. This approach for nonlinear systems has faster convergence than the approach based on the standard extended Kalman filter (EKF) even with inaccurate initial conditions in attitude estimation and navigation problems. The filter formulation employs measurements obtained from a vision sensor to provide multiple line(-) of(-) sight vectors from the spacecraft to another spacecraft. The line-of-sight measurements are coupled with gyro measurements and dynamic models in an UKF to determine relative attitude, position and gyro biases. A vector of generalized Rodrigues parameters is used to represent the local error-quaternion between two spacecraft. A multiplicative quaternion-error approach is derived from the local error-quaternion, which guarantees the maintenance of quaternion unit constraint in the filter. The scenario for bounded relative motion is selected to verify this extended application of the UKF. Simulation results show that the UKF is more robust than the EKF under realistic initial attitude and navigation error conditions.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.93-100
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• 2013

Works of director Robert Zemeckis have attracted much attention after the appearance of in which realistic digital characters appeared. Although he quitted animation production after , his 3D animation contributed to the 3D stereoscopic animation direction considerably. This study compared and analyzed representative 3D stereoscopic works of Robert Zemeckis with special reference to the theoretical background of 3D stereoscopic, cubic effect awareness factor using single eye sight and dual eye sight and matters of consideration in the direction of 3D stereoscopic image. This study also examined an expression method used in his works to improve cubic effects focusing on and .

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.21-25
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• 2016

In this paper, we propose an algorithm for optimal selection of communications for smart lighting in heterogeneous networks. The smart lighting can be used for information communications and lighting simultaneously. To improve BER performance of smart lighting in heterogeneous networks, it adaptively selects a communication method among OCC, Wi-Fi, BLE based on distance between sensors and smart lightings, low power consumption for user requirements, operating time of smart lighting in Line-of-Sight(LOS)/Non-LOS channels. Thus, simulation results demonstrate effectiveness of the proposed algorithm contrary to baseline methods in LOS/NLOS channels.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.185-188
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• 2003

Entrance on the stage of electronic commerce based on internet is acting role that take away regional limitation in commercial transaction. This means that must establish common idea until now in commercial transaction newly, That is, feeler escapes in pattern that is been prior and it means that sight is been prior. We say too much may not be even if success and failure availability of electronic commerce shopping mall catches this sight. And, We Must be able to meet and attach goods purchase by construction of shopping mall through development of correct contents about in various desire of costomer. Therefore, in this paper, we recognize and studied about the efficiency of practical use for useful contents to satisfy customer'a desire in shopping mall construction.