• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.8
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• pp.307-317
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• 2003

We analyze the performance of MC-CDMA and MC-DS/CDMA system on quasi-synchronized moble satellite return link. Quasi-synchronization is considered that chip offset between terminals is within a few chips. In 10-3 BER, performance of MC-DS/CDMA system with walsh code is 0.3dB better than that of MC-CDMA system when the number of user is 5 from -0.5 $T_{c}$ to 0.5 $T_{c}$ quasi-synchronization of MC-DS/CDMA system and from -5/64 $T_{c}$ $^{MC}$ to 5/64 $T_{c}$ $^{MC}$ quasi-synchronization of MC-CDMA system. MC-DS/CDMA system with walsh code is over 0.2dB better than that of MC-DS/CDMA system with extended m code and gold code. MC-CDMA system with walsh code is over 1.2dB better than that of MC-CDMA system with gold code when the number of user is 5 and lower than from -5/32 $T_{c}$ $^{MC}$ to 5/32 $T_{c}$ $^{MC}$ quasi-synchronization.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.47-52
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• 2012

Purpose: This study was to evaluate visual fatigue with passing of watching 3D TV in short term and with experience of watching 3DTV in long term. Methods: 98 adult subjects aged $33.5{\pm}5.5$ years (22 to 51 years; 12 females and 86 males) agreed to participate in this study. Subjects were asked to watch 52 inch LED 2D and 3D television (Shutter glasses method) at 2.7 meters for 65minutes with wearing their habitual glasses or contact lenses. For evaluating visual fatigue, subjects were verbally responded to 11 questions : eye straining, eye paining, dry eye, sore eye, watery eye, photophobia, blur vision, diplopia, eye fatigue, headache, and dizziness with scale 0 to 3 at each measurement while watching 3D and 2D TV. Results: The mean scores of visual fatigue were $2.08{\pm}2.14$, $3.19{\pm}3.02$, $3.40{\pm}3.37$, $3.53{\pm}3.07 $for after 5 minutes, 25 minutes, 45 minutes, and 65 minutes respectively for 3D TV, and $0.40{\pm}1.03$, $0.22{\pm}0.70$, $0.22{\pm}0.58$, and $0.17{\pm}0.52$ after 25, 45, and 65 minutes respectively for 2D TV. Visual fatigue for watching 3D TV was significantly higher than for watching 2D TV at all measurements sessions (paired t-test, p < 0.001). The visual fatigue significantly increased during watching 3D TV for 65 minutes (p < 0.001, RM-ANOVA). The visual fatigue during watching 3D TV was significantly increased until 25 minutes (paired t-test, p < 0.001), stable after that. For correlation between visual fatigue and 3D watching experience, the more 3D watching experiences were significantly the less visual fatigues in photophobia, blur vision, diplopic and dizzy symptoms (ANOVA, all F(1, 96) = 4.500, all p < 0.05), but there was not significantly different in the other symptoms (ANOVA, F (1, 96) = 2.123, p = 0.148). Conclusions: Visual fatigue for watching 3D TV was higher than for watching 2D TV, increase by 25 minutes. It was different by symptoms for correlation between visual fatigue and 3D watching experience.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.31-35
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• 2005

A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. A demonstrator of this concept is made. We will discuss measurements and numerical simulations of the key optical characteristics of this display. The switching characteristics of LC-filled lenticular lenses are discussed and the overlap of the view distributions is introduced as a figure of merit for crosstalk. The 0.62 overlap in our present demonstrator design, gives an excellent 3D image quality, combined with a good depth impression.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.113-120
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• 2019

Mannosylerythritol lipids (MELs) are glycolipids and have several pharmacological efficacies. MELs also show skin-moisturizing efficacy through a yet-unknown underlying mechanism. Aquaporin-3 (AQP3) is a membrane protein that contributes to the water homeostasis of the epidermis, and decreased AQP3 expression following ultraviolet (UV)-irradiation of the skin is associated with reduced skin moisture. No previous study has examined whether the skin-moisturizing effect of MELs might act through the modulation of AQP3 expression. Here, we report for the first time that MELs ameliorate the UVA-induced downregulation of AQP3 in cultured human epidermal keratinocytes (HaCaT keratinocytes). Our results revealed that UVA irradiation decreases AQP3 expression at the protein and messenger RNA (mRNA) levels, but that MEL treatment significantly ameliorated these effects. Our mitogen-activated protein kinase inhibitor analysis revealed that phosphorylation of c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase or p38, mediates UVA-induced AQP3 downregulation, and that MEL treatment significantly suppressed the UVA-induced phosphorylation of JNK. To explore a possible mechanism, we tested whether MELs could regulate the expression of peroxidase proliferator-activated receptor gamma ($PPAR-{\gamma}$), which acts as a potent transcription factor for AQP3 expression. Interestingly, UVA irradiation significantly inhibited the mRNA expression of $PPAR-{\gamma}$ in HaCaT keratinocytes, whereas a JNK inhibitor and MELs significantly rescued this effect. Taken together, these findings suggest that MELs ameliorate UVA-induced AQP3 downregulation in HaCaT keratinocytes by suppressing JNK activation to block the decrease of $PPAR-{\gamma}$. Collectively, our findings suggest that MELs can be used as a potential ingredient that modulates AQP3 expression to improve skin moisturization following UVA irradiation-induced damage.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.1-6
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• 2016

The Internet of Things (IoT) is a new technology paradigm demanding one packaged system of various semiconductor and MEMS devices. Therefore, the development of electronic packaging technology with very high connectivity is essential for successful IoT applications. This paper discusses both fan-out wafer level packaging (FOWLP) and 3D stacking technologies to achieve the integrattion of heterogeneous devices for IoT. FOWLP has great advantages of high I/O density, high integration, and design flexibility, but ultra-fine pitch redistribution layer (RDL) and molding processes still remain as main challenges to resolve. 3D stacking is an emerging technology solving conventional packaging limits such as size, performance, cost, and scalability. Among various 3D stacking sequences wafer level via after bonding method will provide the highest connectivity with low cost. In addition substrates with ultra-thin thickness, ultra-fine pitch line/space, and low cost are required to improve system performance. The key substrate technologies are embedded trace, passive, and active substrates or ultra-thin coreless substrates.

• Journal of Life Science
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• v.33 no.8
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• pp.612-622
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• 2023

T-cell deficiency may occur in various clinical conditions including congenital defects, cell/organ transplantation, HIV infection and aging. In this regard, the development of artificial thymus has recently been attracting much attention. To achieve this aim, the development of techniques for 3D culture of thymic stromal cells is necessary because thymocytes grown only in a 3D thymic microenvironment can be differentiated fully to become mature, immunocompetent T cells; the same cannot be achieved for thymocytes grown in 2D. This study aimed to develop a nanotechnology-based 3D culture technique using polymeric scaffolds for thymic epithelial cells (TECs), the main component of thymic stromal cells. Scanning electron microscopic observation revealed that the pores of both PCL and PCL/PLGA scaffolds were filled with TECs. Interestingly, TECs grown in 3D on polydopamine-coated scaffolds exhibited enhanced cell attachment and proliferation compared to those grown on non-coated scaffolds. In addition, the gene expression of thymopoietic factors was upregulated in TECs cultured in 3D on polydopamine-coated scaffolds compared to those cultured in 2D. Taken together, the results of the present study demonstrate an efficient 3D culture model for TECs using polymeric scaffolds and provide new insights into a novel platform technology that can be applied to develop functional, biocompatible scaffolds for the 3D culture of thymocytes. This will eventually shed light on techniques for the in vitro development of T cells as well as the synthesis of artificial thymus.

• Journal of the Korean earth science society
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• v.31 no.2
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• pp.164-171
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• 2010

The purpose of this study was to investigate the effects of instruction applying 3D Planetarium Software (Starry Night Pro 6.0) in terms of the learners' science achievement, changes of attitude (attitude toward science as well as scientific attitude), and self-directed learning ability. Participants were 198 $8^{th}$ graders. This study adopted a quasi-experimental research design in which experimental group was taught with 3D planetarium software vs. control group with traditional lecture-centered teaching method for 6 hours. The effects were investigated by independent sample t-test and paired sample t-test The results are as follows. The instruction using 3D planetarium software was more effective than the traditional lecture-centered curriculum in science achievement and self-directed learning ability. However, there were not meaningful differences in analyzing attitudes related science, the results that were so effective in elevation for self-directed learning could be gained. Students were interested in instruction applying 3D planetarium software, which was helpful for them to understand the content knowledge. Results showed that instruction with 3D planetarium software applied was effective in $8^{th}$ grade science learning.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.3
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• pp.313-318
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• 1983

It is required in designing a spot welding to get in advance an estimated figure of nugget diameter. A method of estimating nugget diameter of low carbon steel sheets is suggested in tesms of utilizing elastic calculation in theory and of making a sectional observation of specimen of spot welding in experiment. The resultant findings are summarized as follows: 1) A contact diameter of sheet, 2.gamma.$_{o}$=d sub e/+(1.1)t, wheer de is the electrode tip diameter and t is the thickness of sheets. 2) The practical measurement of the nugget diameter reveals that $d_{n}$=(1.05) $d_{e}$+(0.9)t, and $d_{b}$ is less by 0.8-4.3% than 2.gamma.$_{o}$. 3) The more $d_{n}$ is as compared with t, the less the difference between a theoretical value and an experimental value is. 4) In the spot welding of thin steel sheets less than 3mm in thickness that are commonly used in sheet metal works, the contact diameter equals the nugget diameter. In this case, either the theoretical or experimental approach can be used for estimating the nugget diameter.meter.ter.r.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.275-280
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• 2003

The method of simultaneous data acquisition of arteries and veins(SAAV) was suggested to obtain MR angiography of arteries and veins at 0.3T low filed MRI system (Magfinder, AlLab. Korea). Two separated artery- and vein-images were put together using AVCM(Artery-Vein Color Mapping) algorithm and presented in the same image. In this study, artery- and vein-separated angiograms of volunteer's neck were obtained. Two dimensioal blood-enhanced images wre sequentially obtained using SAAV pulse sequence based on time-of-flight(TOF) method with flow compensation. Imaging parameters were TR/TE=70/12msec. FOV=230mm, slice thickness = 3mm, flip angle=90$^{\circ}$, matrix size=256${\times}$256${\times}$64mm. TSat TH/SPA=15/20mm, Ts_v=10msec and Ts_a=40ms. 3D MRA images were reconstructed using the maximum intensity projection(MIP) and the artery-vein color mapping(AVCM) algorithm. This study showed good possibility of clinical applications of MRA in 0.3T which provides valuable diagnostic information of clinical vascular diseases.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.929-933
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• 2010

A new compound, 4-methoxyl 5-hydroxymethyl benzoic 3-O-$\beta$-D-glucopyranoside (1), has been isolated from the leaves and stems of Acer mandshuricum, along with nine known compounds (2-10). Their structures were determined by a variety of spectroscopic analyses. The effect of compounds 1-10 on the function of osteoblastic MC3T3-E1 cells was examined by determining alkaline phosphatase (ALP) activity, collagen synthesis, and mineralization. Compound 1 significantly increased the function of osteoblastic MC3T3-E1 cells; $5.0\;{\mu}M$ of 1 increased ALP activity, collagen synthesis, and mineralization of MC3T3-E1 cells to 114.7, 119.5, and 108.2% (P < 0.05) of the basal value, respectively. In addition, compounds 2-10 also potently increased the function of osteoblastic MC3T3-E1 cells.