• Proceedings of the KSME Conference
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• 2001.06d
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• pp.648-653
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• 2001

This study represents the numerical analysis of natural convection of a microenvironments with a air permeability in the clothing air-layer. The clothing air layer of shoulder and arm was used for numerical analysis model. As a numerical analysis method, we adopted a finite volume method for two-dimensional laminar flow, and analyzed the flow and thermal characteristics of velocity, temperature and concentration in the air layer between body and clothing. As a temperature boundary conditions, we considered that a body skin has a high temperature with $34^{\circ}C$ the environmental temperatures are $5,\;15\;and\;25^{\circ}C$ for various permeability coefficients. The distributions of concentration, temperature and velocity were showed that two large cells were. formed at horizontal and vertical air layer, respectively. As the temperature difference between body skin and environment decrease, the heat transfer was decreased rapidly.

• The Korean Journal of Pain
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• v.14 no.2
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• pp.271-275
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• 2001

Buerger's disease is a nonatherosclerotic occlusive inflammatory disease of the small and medium arteries, and veins of the distal leg or arm. Percutaneous lumbar sympathectomy is used to lower extremity occlusive vascular disease as well as Buerger's disease. Lumbar sympathectomy improves blood flow and provides pain relief in the lower extremity. We report two cases of lumbar sympathectomy using radiofrequency thermocoagulation in patients with Buerger's disease. After no paresthesia and muscle contracture at 50 Hz, 1 volt and 2 Hz, 3 volts, respectively, radiofrequency lesioning was performed for 90 sec at $80^{\circ}C$. After the procedure, both patients showed skin temperature increases greater than $2^{\circ}C$ on the affected extremity. Both patients received relief from pain and symptoms without complications. We consider that lumbar sympathectomy using radiofrequency thermocoagulation is a safe and effective procedure that can relieve pain in patients with Buerger's disease.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.269-271
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• 2007

Follicular thyroid carcinoma with metastasis rarely manifests as spinal cord compression without any previous symptoms of its malignancy. This report describes a 64-year-old man with follicular thyroid carcinoma who presented initially with left arm motor weakness. Magnetic resonance images demonstrated severe cervical cord compression by a mass with destruction of C4 vertebra. Corpectomy of C4 and anterior interbody fusion was carried out. Histopathological study revealed a metastatic follicular carcinoma of the thyroid. We present our case, especially focused of its possible pathophysiology, with review of pertinent literatures.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.520-522
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• 1996

The Direct Drive Arm(DDA) is a SCARA typed direct drive manipulator with two degrees-of-freedom(DOF) using the direct drive motor of the NSK company. A controller system for the SCARA robot of DDA is designed using a DSP (TMS32Oc3O), which has the highest performance among the third DSP chips in the TI company. The design objective of the system is to implement dynamic control algorithms and neural control algorithms for real time learning which require a lot of calculations and large memory and have been tested only by simulations so far. The controller uses a DSP, a high speed D/A, 32-bit Counter and a large DRAM to implement advanced robot control algorithms.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.859-862
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• 2003

This paper proposes an emulation environment for SoC designs using small number of large gate-count FPGA's and a PC system. To overcome the pin limitation problem in partitioning the design when the design size overwhelms the FPGA gate count, we use bus splitter modules that replicate on-chip bus signals in one FPGA to arbitrary number of other FPGA's with minimal pin count. The proposed scheme is applied to the emulation of 2 million gate multimedia processing chip using two Xilinx Viretex-2 6000 FPGA devices in 6.6MHz operating frequency. An ARM core, memories, camera and LCD display are modeled in software using dual 2GHz Pentium-III processors. This scheme can be utilized for more than 2 FPGA's in the same ways as two FPGA case without losing emulation speed.

• Journal of Korea Foundry Society
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• v.18 no.3
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• pp.254-261
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• 1998

Microstructure and mechanical properties of the low pressure die-cast Al wheels were investigated by microscope, image analyzer, NDT (non-destructive test), and tensile test. The variation of SDAS (secondary dendrite arm spacing), porosity per unit area, quality grade, and tensile properties with the mold temperatures were examined. SDAS was gradually decreased with a decrease in temperature. However, the lowest value of porosity per unit area was observed at the mold temperature of $405^{\circ}C$ and the optimum mold temperature was found to be $405^{\circ}C$. Besides, from the observation of pore morphology, it was also found that the pore formation was mainly caused by shrinkage during solidification. The tensile strength, elongation, and impact toughness were markedly decreased, however the yield strength was nearly constant. The decrease of mechanical properties is attributed to the increase of porosity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.629-630
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• 2006

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.327-339
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• 2003

In this paper, a self-organizing fuzzy controller(SOFC) for the industrial robot manipulator with a actuator located at the base is studied A fuzzy login composed of linguistic conditional statements is employed by defining the relations of input-output variable of the controller, In the synthesis of a FLC, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult SOFC is proposed for a hierarchical control structure consisting of basic level and high level that modify control rules. The proposed SOFC scheme is simple in structure, fast in computations and suitable for implementation of real-time control. Performance of the SOFC is illustrated by simulation and experimental results for robot with low joints.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.4
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• pp.289-293
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• 2016

As more mobile devices are equipped with multi-core CPUs and are required to execute many compute-intensive multimedia applications, it is important to optimize the systems, considering the underlying parallel hardware architecture. In this paper, we implement and optimize ray-tracing application tailored to a given mobile computing platform with multiple heterogeneous processing elements. In this paper, a lightweight ray-tracing application is specified and implemented in Kahn process network (KPN) model-of-computation, which is known to be suitable for the description of real-time applications. We take an open-source C/C++ implementation of ray-tracing and adapt it to KPN description in the Distributed Application Layer framework. Then, several possible configurations are evaluated in the target mobile computing platform (Exynos 5422), where eight heterogeneous ARM cores are integrated. We derive the optimal degree of parallelism and a suitable distribution of the replicated tasks tailored to the target architecture.

• Journal of Korean Neurosurgical Society
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• v.48 no.5
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• pp.465-468
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• 2010

Vertebral artery loop formation causing encroachment on cervical neural foramen and canal is a rare cause of cervical radiculopathy. We report a case of 61-year-old woman with vertebral artery loop formation who presented with right shoulder pain radiating to her arm for 2 years. Plain radiograph and computed tomography scan revealed widening of the right intervertebral foramen at the C5-6 level. Magnetic resonance imaging and angiogram confirmed the vertebral artery loop formation compressing the right C6 nerve root. We had considered microdecompressive surgery, but the patient's symptoms resolved after conservative management. Clinician should keep in mind that vertebral artery loop formation is one of important causes of cervical radiculopathy. Vertebral artery should be visualized using magnetic resonance angiography in suspected case.