• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.12
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• pp.3960-3969
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• 1996

A fluid flow inside a circular cylinder subject to horizontal and circular oscillation is analyzed theoretically. Under the assumption of small-amplitude oscillation, the governing equations take linear forms. The velocity field is obtained in terms of the first kind of Bessel function of order 1. It was found that a particle describes an orbit close to a circle in the central region and an arc near the side wall. We also obtained the Stokes' drift velocity induced by the traveling wave along the circumferential direction. The Eulerian streaming velocities at the edge of the bottom and side boundary layers were also obtained. It was shown that the vertical component of the steady streaming velocity on the side wall is almost proportional to the amplitude of the free surface motion.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.7-12
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• 2013

Environmental measurements in the many different types of horticultural farms were carried out to evaluate the ventilation performance for multi-span plastic greenhouses according to the eaves height, the number of spans, the existence of side wall vents and the position of roof vents. Hydroponic tomatoes were being cultivated in all experimental greenhouses, and ventilation rates of the greenhouses were analyzed by the heat balance method. It showed that the ventilation rate in the greenhouse with 4 m eaves height increased about 22% compared to the greenhouse with 2 m eaves height. The ventilation rate in the greenhouse with 9 spans decreased about 17% compared to the greenhouse with 5 spans. In the greenhouse with 9 spans, if there were no side wall vents, the ventilation rate showed about a third of the case that side wall vents were open. Overall, as the eaves height was higher and the number of spans was smaller in multi-span greenhouses, the natural ventilation performance was better. And the ventilation performance was best in the greenhouse which the eaves height was high and the position of roof vents was ridge, not gutter. Therefore, in order to maximize the natural ventilation performance, multi-span plastic greenhouses need to improve their structures such as that make the eaves height higher, place the roof vents on the ridge, install the side wall vents as much as possible, and the number of spans is limited to about 10 spans.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.108.1-108
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• 2002

This paper is willing to propose a method of wall tracing, a moving algorithm between two points, when a Cleaning robot between two points moves. We use the information about obstacles and wall side in calculating different weight vector the each infrared sensors in cleaning robot. Therefore the cleaning robot navigates the wall. In the algorithm of wall tracing, the value of error in angle and distance between starting point and ending point should be zero to navigate the wall safely. The propriety of algorithm of the wall tracing is simulated as this method by using Visual C++. The result simulated proved to the simulation.

• Journal of International Society for Simulation Surgery
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• v.1 no.1
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• pp.16-18
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• 2014

The orbit has a very special anatomical structure. The complex anatomical structure should be restored when we encounter the patient with orbital wall fracture. Unless these specific anatomy were reconstructed well, the patient should suffer from various complications such enophthalmos, diplopia or orbital deformity. In addition, because the patient has a his own specific orbital shape, individualized approach will be necessary. The aim of this trial is to try to restore the original orbit anatomy as possible based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. In order to restore the missing skipped images between the cuts of CT data because of the thinness of the orbital walls, we manipulated the DICOM data for imaging the original orbital contour using the preoperatively manufactured mirror-image of the RP model. And we fabricated Titanium-Medpor to reconstruct three-dimensional orbital structure intraoperatively. This prefabricated Titanium-Medpor was then inserted onto the defected orbital wall and fixed. Three dimensional approach based on the computer simulation turned out to be very successful in this patient. Individualized approach for each patient could be an ideal way to manage the traumatic patients in near future.

• KIEAE Journal
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• v.8 no.6
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• pp.47-55
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• 2008

The purpose of this study is as follows. 1) An element to organize the landscape of an apartment entrance space and setting up, a characteristic of landscape through the actual condition analysis. 2) The characteristic of the type analysis and classified the shape of the entrance as the type. 3) The degree to like the landscape analysis through the making up question. The result of this research is as follows. The entrance of the apartment complex of 71 as of 92 and set an element to organize the landscape and the characteristic of landscape through the frequency analysis and divided an entrance landscape of apartment into 4 types through the cluster analysis. An entrance landscape of apartment types of the entrance is classified as follows. 1) Type I: A model wall-fence type, 2) Type II: The side constructing a building-fence type, 3) type III: The side constructing a building-retaining wall-mixing tree type, 4) type IV: The moulding constructing a building-a retaining wall type.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.102-110
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• 2004

A design code validated against the thermal analysis results of CFD and published RTE code for a regeneratively cooled combustion chamber has been developed. The major function of the code is to predict the regenerative cooling performance and stress of the chamber wall. Adopted are the empirical correlation for the evaluation of the heat transfer coefficient of hot gas and coolant, and theoretical formula for the fin effect of the channel rib. The hot-gas-side wall temperature from the present code shows 100 K difference at most compared to RTE results. It shows less than 10 % difference for the heat flux thrall through the chamber wall and hot-gas-side convective heat transfer coefficient. The major cause of the wall temperature difference is due to the underestimation of the fin effect of the channel rib.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.68-78
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• 1997

A numerical study on the transient vapor flow and heat transfer is performed to investigate the ideal switching operation of heat source in a high temperature heat pipe. The cylindrical 2-dimensional compressible laminar vapor flow is assumed for the vapor space and the conjugate heat transfer for the heat pipe wall, wick and vapor space is calculated. The different boundary conditions such as constant heat flux, convective or radiative boundary at the outer wall are used respectively to compare the influence of boundary conditions on the transient operation. The transient temperature profile and the internal flow of the entire pipe for the switching operation are described as a result. The results show that the transient time is not significantly affected by the boundary conditions at the outer wall in present study. During the transition, two independent flows are observed temporarily on the right side and left side of the heat pipe. It is also found that the trend of temperature variation in the vapor region is different from the variation in the wick and wall region.

• Journal of Korean Neurosurgical Society
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• v.52 no.1
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• pp.67-70
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• 2012

We report a rare case of a spinal intramedullary ependymal cyst in a 46-year-old female and review the 17 pathologically proven cases in the literature. The patient presented with a two-week history of gradually increasing tingling in her left posterior thigh and calf. A preoperative magnetic resonance image revealed a well-defined intramedullary cystic lesion on the ventral side of the spinal cord at the T11 to T12 levels. The lesion was hyper intense in T2-weighted images and hypointense in T1-weighted. The patient underwent a right-side hemilaminectomy at the T11 to T12 levels and fenestration of the cyst wall. After having the cyst wall partially removed and communication established between the cyst and the subarachnoid space, the patient improved neurologically. A histological study of the surgical specimens revealed that the cyst wall consisted of glial cells lined by a simple cuboidal to columnar epithelium. An immunohistochemical examination of the cells lining the cyst wall was positive for S-100 protein, glial fibrillary acidic protein, epithelial membrane antigen, and cytokeratin. We suggest that the optimal treatment of intramedullary ependymal cysts creates adequate communication between the cyst and the subarachnoid space.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1272-1280
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• 2001

An experimental study has been conducted to elucidate the resonance of natural convection in a side-heated square enclosure having a mechanically oscillating bottom wall. Under consideration is the impact of the imposed oscillating frequency, amplitude and the system Rayleigh number on the fluctuation of air temperatures. The experimental results show that the magnitude of the fluctuation of air temperature is substantially augmented at a specific forcing frequency of the oscillating bottom wall. The resonant frequency is increased with the increase of the Rayleigh number and it is little affected by the amplitude of the oscillating wall. It is also found that the resonant frequency is relevant to the Brunt- V$\"{a}$iS$\"{a}$l$\"{a}$ frequency which represents the stratification degree of the system.

• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.107-113
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• 2013

In this study, three different types of experimental models of BIPV curtain wall units with GIGS modules were built, and their thermal and electrical performances were analyzed. The experimental results showed that the temperature of the rear side of the GIGS module with the application of an insulation in the curtain wall spandrels was higher than a GIGS module standalone by $22^{\circ}C$, which results in a reduction in the power generation of the former by 8 %. On the other hand, when ventilation was applied to the model to improve the power generation performance, the module temperature was observed to be $142^{\circ}C$ lower compared to the enclosed type, and the power generation performance improved by 5 %. It confirmed that the temperature increase in the rear side of the GIGS module with insulation layer reduced the electrical performance of the module. Based on this, it is claimed that providing sufficient ventilation at the GIGS applied spandrels contribute to improve the power generation of the GIGS module.