• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.126-134
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• 2015

A simple Couette flow velocity profile with an appropriate correlation for the free terminal rise velocity of a single bubble in a quiescent liquid can produce reliable results for the trajectories of small spherical air bubbles in a low-viscosity liquid (water) provided the liquid remains under uniform shear flow. Comparison of the model adopted in this paper with published results has been accomplished. Based on this study it has also been found that the lift coefficient in water is higher than its typical value in a high-viscosity liquid and therefore a modified correlation for the lift coefficient in a uniform shear flow of water within the regime of the $E\ddot{o}tv\ddot{o}s$ number $0.305{\leq}Eo{\leq}1.22$ is also presented.

• International Journal of Control, Automation, and Systems
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• v.2 no.4
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• pp.435-449
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• 2004

In this paper, a novel anti-sway control system that uses an inclinometer as a sway sensor is investigated. The inclinometer, when compared with a vision system, is very cheap, durable, and easy to maintain, while providing almost the same performance. A number of observers to estimate the angular velocity of the load and the trolley velocity are presented. A state feedback controller with an integrator is designed. After a time-scale analysis, a 1/4-size pilot crane of a rail-mounted quayside crane was constructed. The performance of the proposed control system was verified with a real rubber-tired gantry crane at a container terminal as well as with the constructed pilot crane. Experimental results are provided.

• Korean Journal of Computational Design and Engineering
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• v.6 no.4
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• pp.263-270
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• 2001

In stamping-die manufacturing, the first step is to build die patterns for lost wax casting process. A recent industry trend is to manufacture the die pattern using 3-axis NC machining. This study identifies technical considerations of the pattern machining caused by the characteristics of Styrofoam material, and proposes technical methods related to establishing a process plan and generating tool paths for optimizing the pattern machining. In this paper, the process plan includes the fellowing three items: 1) deter-mining a global machining sequence-a sequence of profile, top, bottom machining and two set-ups, 2) extracting machining features from a pattern model and merging them, and 3) determining a machining sequence of machining features. To each machining feature, this study determines the machining start point, generates the approach tool path, and proposes a tool path linking method fur reducing the distance of the cutter rapid motion. Finally, a smooth tool path generation and an automatic feedrate adjustment (AFA) method are introduced far raising the machining efficiency.

• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.11-20
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• 2010

The purpose of this study is the investigation of the wave interaction with the rectangular floating breakwater. The flow profile obtained by PIV technique is represented to understand the vortical flow due to the wave interaction with a rectangular floating breakwater in the roll motion and the fixed condition. Also, the transmission coefficients are compared in both conditions over the extensive wave periods, which represent the performance of breakwater to attenuate the incoming waves. These results would be applied to design the floating breakwater having the mooring system to improve its performance for a certain wave period.

• Speech Sciences
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• v.10 no.4
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• pp.221-227
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• 2003

Diadochokinetic (DDK) speech task has been utilized as an evaluating tool for speakers with dysarthria for many years. This study attempted to differently diagnose multiple system atrophy (MSA) from idiopathic Parkinson's disease (PD) using patients' performance of DDK (i.e., alternate motion rate (AMR)). The subjects included 11 cases of pathologically confirmed MSA and 16 IPD patients who commonly presented with parkinsonian syndrome. The speech sample of each patient was analyzed acoustically using the MSPTM(Motor Speech Profile, a module of CSL). The results showed that the average DDK rate was significantly faster in the IPD than the MSA groups in all three syllables (i.e., /puh/, /tuh/. and /kuh/). We propose the average DDK rate variable as a core clinical trait in differentiating the two pathological conditions.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.436-441
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• 2001

In this paper, stacker crane is modeled as rigid elements and discrete flexible beam connections by kinematics & dynamics solver package program instead of deriving the equations of motion which describes the total dynamics of the system. For the simulation of structural dynamics, ADAMS, a software for the simulation of multiple rigid body dynamics, is used. Some kinds of works are fulfilled to examine the dynamic characteristics of system. In order to verify the analysis method, the results of simulation and experiment are compared.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2082-2087
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• 2004

In this study, the variation of spark plug location in the combustion chamber was investigated for the sake of emission characteristics from SI engine by using PDA valve. The swirl is ong of the important parameters that effects emission characteristics. PDA valve has been used to satisfy the requirements of sufficient swirl generation to improve combustion and emission reduction to effect on flow profile on a combustion chamber. Especially, the variation of spark plug location have an important effect to analyze exhaust gas and the early flame propagative process. Therefore, this test is forced that injection timing, spark timing and intake air motion govern the stable combustion. From the results, it showed that the variable spark plug location and PDA valve can be reduced exhaust gas.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.2 s.21
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• pp.49-57
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• 2005

The target localization using the line arrays buried in the seabed is a difficult problem due to the complex sea bottom characteristics and need to compensate the wave propagation effect to localize the target accurately Sound speed mismatch in the seabed causes a bias in the target bearing estimation and induces the localization error. In this paper we describe a target localization method with improved accuracy of target bearing and localization by calibration the sound speed in the seabed. The proposed algorithm is verified through the ocean data.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.43-46
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• 2003

본 논문에서는 영상의 특성을 이용하여 TM1300 미디어 프로세서에 적합한 효율적인 움직임 탐색방법을 제안한다. 주위 블록간의 공간 상관 관계를 이용해 예측 움직임 벡터를 구하고 이를 기준으로 탐색 영역을 축소하여 전체 연산량을 줄인다. TMI1300의 특성을 활용하여 메모리 사용 효율 증대 및 비교, 분기의 사용을 줄여 최적화에 유리한 움직임 예측 방법을 제안한다. 제안된 방법을 Philips 140 MHz IM1300 상의 MPEG-4 SP@L3 (Simple Profile Level 3) 부호화기에 적용한 결과 화질은 전역 탐색 방법에 근접하며 기존의 고속 움직임 예측 방법에 비해 메모리 접근 및 처리 속도 면에서 향상된 성능을 보였다.

• Journal of Magnetics
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• v.16 no.1
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• pp.6-9
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• 2011

Spin-motive force has drawn attention because it contains a fundamental physical property. Spin-motive force creates effective electric and magnetic fields in moving magnetization; a vortex is a plausible system for observing the spin-motive force because of the abrupt profile of magnetization. However, the time-averaged value of a spin-motive force becomes zero when a vortex core undergoes gyroscopic motion. By means of micromagnetic simulation, we demonstrates that a non-zero time-averaged electric field induced by spin-motive force under certain conditions. We propose an experimental method of detecting spin-motive force that provides a better understanding of spin transport in ferromagnetic system.