• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.813-816
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• 2008

In this research we present a method to reconstruct the casting flow simulation result as a 3D model and visualize it on a VR display. First, numerical analysis of heat flow is performed using an existing commercial CAE simulation software. In this process the shape of the original design model is approximated to a regular rectangular grid. The filling ratio and temperature of each voxel are recorded iteratively by predefined number of steps starting from pouring the melted metal into a mold until it is entirely filled. Next we reconstruct the casting by voxels using the simulation result as an input. The color of voxel is determined by mapping the colors to temperature and filling ratio at each step as the flow proceeds. The reconstructed model is visualized on the Projection Table which is one of horizontal-type VR display. It provides active stereoscopic images.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.843-848
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• 2015

The objective of this study is to observe and optimize a typical ocean environment and reduce wave reflections in the wave flume. In order to generate ocean waves in the wave flume, a combination of a horizontal piston type wave generator and wave absorbers was installed in the channel. Two probes for measuring the wave heights, i.e., wave level gauges, were used to record the continuous variation of the wave surface, the phase difference, and the maximum (crest) and minimum (trough) points of the propagating waves. In order to optimize the shape and size of the propagating waves, several absorption methods were proposed. Apart from an active wave absorption method, we used methods that involved vertical porous plates, horizontal punching plates, and sloping-wall-type wave absorbers. To obtain the best propagating waves, a sloping-wall-type wave absorber was chosen and tested in terms of the constitutive filling materials and the location and shape of the plate. This study also focused on the theoretical prediction of the wave surface, separating them into the incident and reflective components. From the results, it is evident that the wave absorber comprising a hard filling material exhibits a better performance than the absorber comprising a soft material, i.e., the wave absorber can be a strong sink to control the energy of the incoming wave. In addition, larger wave absorbers correspond to lower reflectance because a larger volume can reduce the incoming wave energy. Therefore, at constant absorber conditions, the reflectance of the wave increases as the wave period increases. Finally, the reflectance of the wave was controlled to be less than 0.1 in this study so that the wave flume can be used to simulate an offshore environment.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.484.2-484.2
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• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.263-267
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• 2009

The purpose of this study is to evaluate the efficacy of stipulated cleaning process, and the prohibition of cross-contamination and microbiological contamination, which inadequate cleaning in multi-production could occur, through cleaning validation of multi-purpose facility used to produce five biopharmaceutical products as sterile injection. After production of five biopharmaceutical products such as hGH, rhGCSF, rhEPO, rhFSH and rhIFN using vial filling machine, the cleaning validation such as residual analysis of active ingredients or human serum albumin, measurement of total organic carbon (TOC), residual analysis of detergent and microbiological contamination were carried out. In the case of rhGH and rhGCSF clean validations, drug residues were not detected. Furthermore, in the case of rhEPO, rhFSH and rhIFN clean validations, human serum albumin residues were not detected. At TOC (total organic carbon) analysis, all clean validations gave the TOC of about average 137.93%, not more than 150% of acceptance criteria. At sodium analysis for the checking of residues of cleaning agent, sodium residues were not detected. In sterility test, they showed no microbiological contamination of bacteria and fungi. Thus, this cleaning validation was determined as successful in protection of cross-contamination and induction of safety in multi-purpose facility.

• Journal of Crop Science and Biotechnology
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• v.10 no.4
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• pp.281-286
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• 2007

Gibberellins are growth hormones that play a pivotal role in the growth and development of plants. Present investigations were carried to check the effect of nitrogen(N) and silicon(Si) on bioactive $GA_1$ and its immediate precursor $GA_{20}$ at different growth stages of two rice cultivars with different maturity traits. It was observed that the endogenous bioactive $GA_1$ level gradually increased during vegetative stage and anthesis stage of both Junghwabyeo(early flowering cultivar) and Daesanbyeo(late flowering cultivar). However, the $GA_1$ and $GA_{20}$ content start decreasing during the seed filling stage in both rice cultivars, which indicated a possible relationship of bioactive $GA_1$ and floral development. Our results also confirmed that early 13-hydroxylation pathway was operated at all developmental stages of rice plant. Variation in the levels of the endogenous gibberellins in rice shoots were measured by GCMS-SIM using $^2H_2$-labeled gibberellins as internal standards. Combined application of N and Si enhanced growth parameters and reduced lodging index of both rice cultivars. It was thus concluded that the level of physiologically active $GA_1$ increased during vegetative and early reproductive stage, but starts declining at seed filling stage.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.1
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• pp.13-22
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• 1999

The purpose of this investigation was to evaluate the acceptability of the collagen-based xenograft ($Laddec^{(R)}$). Full thickness bone defects were prepared in the calvaria of the rats. In the experimental groups the bone defects were filled with a kind of collagen based xenograft. And bone defects, which left without filling, were used as control groups. Sequential sacrifice was performed at the 1st, 2nd, 4th, 8th, and 16th weeks of experiment. 1. At the 1st week of experiment, infiltration of chronic inflammatory cell was observed in all groups. In the experimental group, resorption of the xenograft was initiated. 2. At the 2nd week of experiment, infiltration of chronic inflammatory cells was decreased in all groups. In the experimental group, active resorption of xenograft and new bone formation from the periphery of the xenograft was observed. 3. At the 4th and 8th weeks of experiment, more resorption of the xenograft and new bone formation with calcification was observed in the experimental group. 4. At the 16th week of experiment, small bone trabecula was formed partially in the control group but that couldn't fill the whole bone defect. In the experimental group, more advanced resorption of xenograft and more new bone formation was observed. However mid portion of the xenograft was still remained without resorption. 5. From this experiment, we concluded that the collagen-based xenograft had some osteoconductive but no osteoinductive property. So the xenograft would be used for the bone defect filling material where rapid bone remodeling is not required.

• Journal of Biomedical Engineering Research
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• v.19 no.4
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• pp.385-391
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• 1998

A new balancing method of atrial pressures balancing for the moving actuator total artificial heart(TAH) without an extra compliance chamber was developed. The asymmetric operation of the pendulous moving actuator have made it possible to compensate the left and right pump output difference by utilizing the interventricular air space as an internal compliance chamber in a pump housing. Furthermore, the balancing performance between left and right pump outputs is increased through the improvement of the flexibility of part of the polyurethane housing. However, the increase of the flexibility of the pump housing causes a little loss of the cardiac output due to the reduction of active filling property. In this paper., a good condition between the balance and pump output performance is evaluated by adjusting the air volume in the interventricular space through a series of in vitro experiments. This new pump was implanted in a sheep weighting 63kg, and it survived for 3 days and the average cardiac output during postoperative days was about 4.2 L/mim with the atrial pressures under 15 mmHg.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.5149-5167
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• 2017

Reducing energy consumption in a wireless video sensor network (WVSN) is a crucial problem because of the high video data volume and severe energy constraints of battery-powered WVSN nodes. In this paper, we present an adaptive dynamic resizing approach for a SRAM communication buffer in a WVSN node in order to reduce the energy consumption and thereby, to maximize the lifetime of the WVSN nodes. To reduce the power consumption of the communication part, which is typically the most energy-consuming component in the WVSN nodes, the radio needs to remain turned off during the data buffer-filling period as well as idle period. As the radio ON/OFF transition incurs extra energy consumption, we need to reduce the ON/OFF transition frequency, which requires a large-sized buffer. However, a large-sized SRAM buffer results in more energy consumption because SRAM power consumption is proportional to the memory size. We can dynamically adjust any active buffer memory size by utilizing a power-gating technique to reflect the optimal control on the buffer size. This paper aims at finding the optimal buffer size, based on the trade-off between the respective energy consumption ratios of the communication buffer and the radio part, respectively. We derive a formula showing the relationship between control variables, including active buffer size and total energy consumption, to mathematically determine the optimal buffer size for any given conditions to minimize total energy consumption. Simulation results show that the overall energy reduction, using our approach, is up to 40.48% (26.96% on average) compared to the conventional wireless communication scheme. In addition, the lifetime of the WVSN node has been extended by 22.17% on average, compared to the existing approaches.

• Journal of the Korean Institute of Gas
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• v.4 no.1 s.9
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• pp.9-15
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• 2000

In order to investigate the structural defects of a cylindrical-type toluene storage tank, we carried out the acoustic emissions. The storage tank was manufactured with high strength steel in 1978 and its's first and second courses from bottom were entirely repaired, recently. Acoustic emissions were monitored with real time according to load sequences in the $75{\~}84\%$ level range of maximum allowable load. Our results show a non-genuine acoustic emissions as well as a genuine characteristics. The pseudo emissions considered as valve noises were transiently occurred on shut-off processes of inlet valve regardless of water loading. The acoustic emission events occurred during water filling phase were estimated due to defects, and in the $75{\~}84\%$ test load level no evidences of defect growth were observed. Those defects were ascertained as weld cracks and porosities through the post radiography testing conducted near active sensors.

• Korean Journal of Computational Design and Engineering
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• v.13 no.6
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• pp.403-411
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• 2008

The alignment of facial images is crucial for 2D face recognition. This is the same to facial meshes for 3D face recognition. Most of the 3D face recognition methods refer to 3D alignment but do not describe their approaches in details. In this paper, we focus on describing an automatic 3D alignment in viewpoint of quantitative analysis. This paper presents a framework of 3D face alignment and normalization based on feature points obtained by Active Shape Models (ASMs). The positions of eyes and mouth can give possibility of aligning the 3D face exactly in three-dimension space. The rotational transform on each axis is defined with respect to the reference position. In aligning process, the rotational transform converts an input 3D faces with large pose variations to the reference frontal view. The part of face is flopped from the aligned face using the sphere region centered at the nose tip of 3D face. The cropped face is shifted and brought into the frame with specified size for normalizing. Subsequently, the interpolation is carried to the face for sampling at equal interval and filling holes. The color interpolation is also carried at the same interval. The outputs are normalized 2D and 3D face which can be used for face recognition. Finally, we carry two sets of experiments to measure aligning errors and evaluate the performance of suggested process.