• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.456-459
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• 1995

The problem of compliant motion control using a redundant manipulator is addressed in this article. Specifically, a hybrid-control type and impedance-control type controllers are extended to general redundant manipulators based on the kinematically decomposed and geometrically compatible modeling of its joint space. In the case of the hybrid controller, it leads to the linear and decoupled closed-loop dynamics in the three motion spaces, that is the motion-controlled, force-controlled, and the null motion-controlled spaces of the redundant manipulator. When the proposed impedance controller is applied, the decoupled impedance models in three motion spaces are obtained. The superiority of the proposed controllers is verified with the numerical experiments.

• Journal of the Korean Society of Combustion
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• v.14 no.2
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• pp.32-41
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• 2009

The transported probability density function model combined with the consistent finite volume (FV) method has been applied to simulate the turbulent bluff-body reacting flows. To realistically account for the non-isotropic turbulence effects on the turbulent bluff-body reacting flows, the present PDF transport approach is based on the joint velocity- turbulent frequency-composition PDF formulation. The evolution of the fluctuating velocity of a particle is modeled by a simplified Langevin equation and the particle turbulence frequency is represented by the modified Jayesh - Pope model. Effects of molecular diffusion are represented by the interaction by exchange with the mean (IEM) mixing model. To validate this hybrid FV/PDF transport model, the numerical results are compared with experimental data for the turbulent bluff-body reacting flows.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.1957-1975
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• 2016

The outage probability (OP) performance of multiple-relay-based incremental hybrid decode-amplify-forward (IHDAF) relaying mobile-to-mobile (M2M) networks with transmit antenna selection (TAS) over N-Nakagami fading channels is investigated in this paper. The closed-form expressions for approximate OP of the optimal and suboptimal TAS schemes are derived. The power allocation problem is formulated for performance optimization. Then the OP performance under different conditions is evaluated through numerical simulations to verify the analysis. The simulation results showed that optimal TAS scheme has a better OP performance than suboptimal TAS scheme; the power-allocation parameter has an important influence on the OP performance.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.2
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• pp.97-109
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• 2014

This paper considers a reverse supply chain with simultaneous recovery of used products and manufacturing of brand-new ones. Recovered products are downgraded and have to be sold in a market different from that of brand-new products at a different price. In case of a shortage of recovered product inventory, a brand-new item, if available, can be offered at the price of a recovered product. In other words, one-way demand substitution is allowed. We address the joint decision of when to manufacture brand-new product, when to recover returned product, and how to control demand substitution to maximize the hybrid production system's profits. To this end, we propose a Markov decision Process model and investigate the structure of the optimal policy. Performance comparison is numerically implemented between the models with and without downward demand substitution option under different operating conditions of the system parameters.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.113-116
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• 2004

No specific guidelines are for computing the shear strength of steel coupling beam connections embedded in the reinforced concrete shear wall. In this paper, a theoretical study of the strength of hybrid coupled shear wall connections is achieved. The bearing stress at failure in the concrete below the steel coupling beam section is related to the concrete compressive strength and the ratio of the width of the steel coupling beam section to the thickness of the hybrid coupled shear wall. To revise factor affecting shear transfer strength across connections between coupled shear walls and steel coupling beam, experimental studies are achieved. The main test variables were auxiliary details of stud bolts. In this studies, these proposed equations are shown to be in good agreement with the test results reported in the paper and with other test data in the literature.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.291-300
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• 2000

This paper proposes the new hybrid analysis of vibration in the medium to high frequency ranges including PFA and SEA concept. The core part of this method is the applications of coupling loss factor(CLF) instead of power transmission, reflection coefficients in boundary condition. This method shows very promising compared to the classical PFA for the various damping loss factors and wide ranges of frequencies. Besides this paper presents the applicable method in Power Flow Finite Element Method by forming the joint element matrix with CLF. These hybrid concepts are expected to improve SEA and PFA methods in vibration analysis.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.141-142
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• 2018

360 비디오는 VR 미디어의 확산과 함께 몰입형 미디어로 주목 받고 있으며, JVET(Joint Video Experts Team)에서는 post-HEVC 로 진행중인 VVC(Versatile Video Coding) 표준화에 360 비디오 부호화도 함께 포함하고 있다. 현재 JVET 에서는 360 비디오를 부호화 하기 위한 다양한 구(sphere) 영상의 2D 투영기법이 고려되고 있다. 이러한 2D 투영에서는 구 영상의 화소 샘플이 2D 영상에 비 균일하게 매핑되는 변환 왜곡이 발생하며, 이는 360 비디오의 부호화 효율을 저하시키는 원인이 된다. 본 논문에서는 CMP 의 개선된 투영기법인 기존의 EAC(Equi-Angular Cubemap)와 HEC(Hybrid Equiangular Cubemap)를 소개하고, 이를 바탕으로 HEC 의 확장 변환 기법을 제시하여 객관적/주관적 부호화 성능을 확인한다.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.10
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• pp.865-871
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• 2015

This study was conducted in order to develop a finger exoskeleton system using ionic polymer metal composites (IPMCs) as the actuator and sensor in a hybrid structure. To use the IPMC as an actuator producing large force, a first order transfer function was obtained using results from a block force for DC excitation that applied to two IPMCs of 20mm-width, 50mm-length, and 2.4mm thickness together. After which the validation of 200gf control with anti-windup PI controller was confirmed. A 5mm-width, 50mm-length, 0.6mm-thickness of IPMC was also modeled as a sensor for tip displacement. As a result, the IPMC sensor could been utilized as a trigger role for the actuator. Finally, an IPMC sensor and actuator were installed on the joint of a single DOF exoskeleton in the hybrid structure, and test for the control of 40gf of block force and predefined sequence of motion was performed.

• Journal of Welding and Joining
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• v.24 no.5
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• pp.49-56
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• 2006

For laser welding in shipbuilding industry, gap bridging capability is one of the most important characteristics to achieve the high productivity and good weld quality. Recently, laser-GMA hybrid welding process is regarded as a distinctive method to overcome the tight gap tolerance with improving the productivity. In this study, the influence of process parameters on the bead formation was experimentally analyzed and the relationship between the process parameters and geometric imperfections was investigated. It was revealed that undercut, excessive weld metal, excessive penetration and incompletely filled groove were the major geometric imperfections. The optimized wire feeding and arc pressure were necessary to ensure the gap bridging ability. The approach to select the process parameters was conducted for butt welding with up to 2mm joint gap, in which the sound weld beads were generated without changing the welding speed.

• Journal of Powder Materials
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• v.20 no.4
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• pp.302-307
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• 2013

A5J32-T4 and A5052-H32 dissimilar aluminum alloy plates with thickness of 1.6 and 1.5 mm were welded by friction stir lap welding (FSLW). The FSLW were studied using different probe length tool and various welding conditions which is rotation speed of 1000, 1500 rpm and welding speed of 100 to 600 mm/min and material arrangement, respectively. The effects of plunge depth of tool and welding conditions on tensile properties and weld nugget formation. The results showed that three type nugget shapes such as hooking, void, sound have been observed with revolutionary pitch. This plunge depth and material arrangement were found to effect on the void and hooking formation, which in turn significantly influenced the mechanical properties. The maximum joint efficiency of the FSLWed plates was about 90% compared to base metal, A5052-H32 when the A5052-H32 was positioned upper plate and plunge depth was positioned at near interface between upper and lower plates.