• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.8-15
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• 2020

The diffusion cell method is the main technique employed for the in vitro diffusion test of transdermal drug delivery preparations. Most existing transdermal diffusion devices use a water bath heating structure and direct current motor magnetic stirrer. However, these devices are confronted with problems, such as large volume, incompatible vertical and horizontal diffusion cells, few diffusion cell sets, and poor reliability. To overcome these deficiencies, the system adopts a dry heating method and uses a rotating magnetic field generated by the electromagnetic stirrer to drive the magnetic stirrer. Accordingly, the resulting device is characterized by a simple structure and small volume, convenient operation, compatible vertical and horizontal diffusion cells, and numerous diffusion cell sets. The reliability and practicability of the system is verified by the in vitro percutaneous permeability test of the bisoprolol patch.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.48-60
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• 2011

Nowadays, the 3D community is actively researching on 3D imaging and free-viewpoint video (FVV). The free-viewpoint rendering in multi-view video, virtually move through the scenes in order to create different viewpoints, has become a popular topic in 3D research that can lead to various applications. However, there are restrictions of cost-effectiveness and occupying large bandwidth in video transmission. An alternative to solve this problem is to generate virtual views using a single texture image and a corresponding depth image. A critical issue on generating virtual views is that the regions occluded by the foreground (FG) objects in the original views may become visible in the synthesized views. Filling this disocclusions (holes) in a visually plausible manner determines the quality of synthesis results. In this paper, a new approach for handling disocclusions using depth based inpainting algorithm in synthesized views is presented. Patch based non-parametric texture synthesis which shows excellent performance has two critical elements: determining where to fill first and determining what patch to be copied. In this work, a noise-robust filling priority using the structure tensor of Hessian matrix is proposed. Moreover, a patch matching algorithm excluding foreground region using depth map and considering epipolar line is proposed. Superiority of the proposed method over the existing methods is proved by comparing the experimental results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.5
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• pp.38-43
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• 2015

In this paper, we present novel dual-band microstrip antennas using inverted-L-shaped parasitic elements vertically at radiation apertures for GPS L1(1.575 GHz) and L2(1.227 GHz) bands. For making dual band which has large interval, the inverted-L-shaped parasitic element was loaded at the radiation aperture of a half-wavelength patch antenna(GPS L1) in opposite direction of the feeding point for receiving the low frequency(GPS L2). The low frequency occurs by perturbation and coupling between the patch and parasitic. Next, due to use circular polarizations at the GPS applications, two inverted-L-shaped parasitic elements were loaded at radiation apertures of each polarizations and the feeding point was moved at diagonal part of the patch. The dimensions of the designed circularly polarized antenna were $88.5{\times}79{\times}10.4mm^3$ ($0.36{\lambda}L{\times}0.32{\lambda}L{\times}0.04{\lambda}L$, ${\lambda}L$ is the free-space wavelength at 1.227 GHz). Measured -10 dB bandwidths were 116.3 MHz(7.4%) and 64.3 MHz(5.2%) at GPS L1 and L2 bands, respectively. All of these cover the respective required system bandwidths. The measured 3 dB axial ratio bandwidths were 11.7 MHz(0.74%) and 14 MHz(1.14%), respectively. Within each of the designed bands, broadside radiation patterns were observed.

• Korean Journal of Environment and Ecology
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• v.26 no.6
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• pp.952-959
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• 2012

This study examined habitat fragmentation that has occurred in Paju and Yeoncheon, the two border municipalities between North and South Korea in Gyeonggi-do (province) during the last 17 years using various landscape metrics. We 1) classified grass and agricultural habitats and forest habitats from two Landsat TM images collected in 1990 and 2007, and 2) compared the percentage of class area, patch density, mean patch area, and mean perimeter area ratio for the two habitat types between the two time points. Both types of habitats has been severely fragmented due to urban development in the last 17 years. The increased patch density and decreased mean habitat area are attributed to the construction of roads and railroads that separate a large habitat to many small pieces. The increased mean perimeter area ratio also indicates that the habitat fragmentation extended areas that are affected by the edge effect and so less suitable for interior species. A habitat conservation plan is urgently needed to minimize habitat fragmentation from developments that are expected to soon occur in the north and south Korean border.

• Korean Journal of Environment and Ecology
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• v.26 no.2
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• pp.247-256
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• 2012

We evaluated the landscape ecological value of selected minefields and wetland patches as a habitat of the forest bird community. The avian fauna of three minefields of 8.5ha, 17.4ha, and 40.6ha were evaluated by comparing that of three control sites of mountain area. Average number of forest bird species, number of individuals, species diversity index, species richness, and species evenness were analyzed according to the size of patch and environmental characteristics such as the presence of wetland and connectivity. Community similarity was evaluated between test and control plots. Avian fauna can be summarized as follows. First, 63 species were recorded, and the sum of maximum counts was 828 individuals. Species diversity index was 3.8, and the species richness was 9.2. Species evenness was 93.3. Second, small, isolated forest patch had a low average number of species and individuals as expected. But, small forest patches with streams had higher bird density than patches without water surface. Third, forest patches with marsh wetland were evaluated as lower habitat quality than forest patches with stream wetland in terms of the number of bird species per unit area, number of individuals per unit area, species diversity index, species richness index, and species evenness. Finally, Community similarity of the small forest patches with streams was similar with large connected forest. As a result, lowland forest patch was shown the good quality for the forest bird community in spite of small extents, and community structure was similar with mountain forest bird community. Thus, riparian forest restoration could improve the biodiversity of the forest bird community.

• Journal of Chest Surgery
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• v.33 no.6
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• pp.476-486
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• 2000

Background: Pulmonary atresia with intact ventricular septum(PA/IVS) is an anatomically heterogenous anomaly with a variety of surgical strategies possible. The purpose of the study is to evaluate the influence of right ventricular size on the early and midterm results of surgical repair of PA/IVS. Material and method: Medical records of 20 consecutive patients with PA/IVS operated on between January 1993 and August 1999 were retrospectively reviewed. There were 12 boys and 8 girls whose ages ranged from 2 days to 14.5 months (median 6 days). Their body weight ranged from 2.52kg to 9.35 kg(median 3.18kg). The preoperative Z-value of the diameter of the tricuspid valve(T-valve) was less than or -4 in 5 patients, between -4 and -2 in 1, between -2 and 0 in 7, between 0 and 2 in 6, and greater than or 2 in 1. All patients who had z-value of tricuspid valve greater than -2.05 were attempted biventricular repair(n=15) and all patients who had it smaller than -4.4 underwent systemic-pulmonary shunt operation only(n=3) or bidirectinal cavopulmonary shunt with right ventricular reconstruction(n=2). Result: Two early deaths(2/20, 10%) occurred. Both were infants who underwent transannular patch with shunt. One of these two had huge right ventricle(Z-value of tricuspid valve = 5). There were 2 late non-cardiac deaths 3 and 7 months after operations respectively. Follow-up was completed in all children at a mean of 35.3 months(range, 5 to 54 months). 10 of 11 survivors who underwent transannular patch or valvotomy with or without shunt procedure were in NYHA functional class I even though some of them had small interatrial communication or patent shunt. All three patients who had shunt procedure only at initial palliation completed Fontan procedures with no death. Two patients who underwent right ventricular outflow reconstruction with bidirectional cavopulmonary shunt were also in good condition. Conclusion: The transanular RVOT patch or valvotomy with or without systemic-pumonary shunt as an initial palliative procedure to achieve biventricular repair for the patients who had neither too small nor too large right ventricle(-2.05$\leq$Z-value of T-value of T-valve$\leq$2) could be performed at low operative risk(1/14 7.1%). Systemic-pulmonary shunt procedure and bidirectional cavopulmonary shunt procedure for the patients who had small right ventricle(Z-value of T-valve$\leq$4.4) could be also performed with low risk. But a patient with huge right atrium and ventricle(Z-value of t-valve=5) had poor operative result.

• The Korean Journal of Physiology
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• v.28 no.1
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• pp.37-50
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• 1994

Synthetic potassium channel openers (KCOs) are agents capable of opening K-channels in excitable cells. These agents are known to have their maximal potency in the smooth muscle tissue, especially in the vascular smooth muscle. Much attention has been focused on the type of K-channel that is responsible for mediating the effects of KCOs. As the KCO-induced changes are antagonized by glibenclamide, an $K_{ATP}$ (ATP-sensitive K-channel) blocker in the pancreatic ${\beta}-cell,\;K_{ATP}$ was suggested to be the channel responsible. However, there also are many results in favor of other types of K-channel $$(maxi-K,\;small\;conductance\;K_{Ca,}\; SK_{ATP}) mediating the effects of KCOs. Effects of lemakalim, (-)enantiomer of cromakalim (BRL 34915), on the spontaneous contractions and slow waves, were investigated in the antral circular muscle of the guinea-pig stomach. Membrane currents and the effects on membrane currents and single channel activities were also measured in single smooth muscle cells and excised membrane patches by using the patch clamp method. Lemakalim induced hyperpolarization and inhibited spontaneous contractions in a dose-dependent manner. These effects were blocked by glibenclamide and low concentrations of tetraethyl ammonium (< mM). Glibenclamide blocked the effect of lemakalim on the membrane potential and slow waves. The mechanoinhibitory effect of lemakalim was blocked by pretreatment with glibenclamide. In a whole ceIl patch clamp condition, lemakalim largely increased outward K currents. These outward K currents were blocked by TEA, glibenclamide and a high concentration of intracelIular EGTA (10 mM). Volatage-gated Ca currents were not affected by lemakalim. In inside-out patch clamp experiments, lemakalim increased the opening frequency of the large conductance $Ca^{2+}-activated$ K channels $(BK_{Ca},\;Maxi-K).$ From these results, it is suggested that lemakalim induces hyperpolarization by opening K-channels which are sensitive to internal Ca and such a hyperpolarization leads to the inhibition of the spontaneous contraction.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.3
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• pp.31-37
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• 2015

In this paper, newly proposed dual-band microstrip antennas using stacked inverted-L-shaped parasitic elements are presented for GPS $L_1(1.575GHz)$ and $L_2(1.227GHz)$ bands. For making dual band which has large interval, ${\lambda}/4$($L_1$ band) inverted-L-shaped parasitic elements were stacked at both side of radiation apertures on the half-wavelength($L_2$ band) patch antennas. The resonance in the parasitic elements occurs through coupling to the patch. Next, due to using circular polarization at GPS, ${\lambda}/4$($L_1$ band) inverted-L-shaped parasitic elements was stacked using sequential rotation technique on the patch and both side of the diagonal corners of the antenna were eliminated to make dual-band circular polarization. The designed circular polarized antenna's dimensions are $0.43{\lambda}L{\times}0.43{\lambda}L{\times}0.06{\lambda}L$ (${\lambda}L$ is the free-space wavelength at 1.227 GHz). Measured -10 dB bandwidths was 120 MHz(7.6%) and 82.5 MHz(6.7%) at GPS $L_1$ and $L_2$ bands. and 3 dB axial ration bandwidths are 172 MHz(10.9%) and 25 MHz(2.03%), respectively. All of these cover the respective required system bandwidths. Within each of the designed bands, broadside radiation patterns were observed.

• Journal of Space Technology and Applications
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• v.1 no.1
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• pp.33-40
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• 2021

Based on the requirements of a total weight of 42 kg or less, the NEXTSat-2 SAR (synthetic aperture radar) system was developed. As the NEXTSat-2 is a small-sized satellite, the SAR system was designed to account for about 40% of the dry mass of the payload relative to the total mass. Among the major components of the SAR system - which are an antenna, an RF transceiver, a baseband signal processor, and a power unit - a part with a particularly large dry mass is the antenna, the core of the SAR system. Whereas various selections are possible in consideration of gain and efficiency when designing the antenna, the micro-strip patch array antenna was adopted by reflecting the dry mass, power, and resolution required by the NEXTSat-2 project. In order to meet the mission requirement of the NEXTSat-2, the antenna was developed with a frequency of 9.65 GHz, a gain of 42.7 dBi, and a return loss of -15 dB. The performance of the antenna was verified by conducting a field test onboard the vehicle.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5_2
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• pp.135-143
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• 2010

The 21st century is currently undergoing an era of urban regeneration. The purpose of this research is to secure and expand the green infrastructure with zoning regulation in the context of urban regeneration. This objective also seeks a way of urban regeneration through the use of existing large parks by employing park-based mixed use districts around the periphery of large urban parks and green spaces. This research examines the limits, problems of existing single- and mixed-use zoning districts for securing of green infrastructure by book review. This research finally advocates introducing a another type of urban mixed-use districts, namely park-based mixed use district and its characteristics and functions, by using landscape ecology and landscape urbanism as a theoretical basis. The results of this research suggested that large parks and green spaces should be considered as one of patch in landscape ecology. This research also discusses the possibility that, as patches have ecotones with greater biodiversity in the peripheral areas of it, the green infrastructure can be constructed around the periphery of large urban large parks and green spaces by introducing cultural ecotone of nature's convergence with the city. As a result, the green infrastructure and high density of land use and using behaviour can be increased. Park-based mixed use districts encourage the convergence of parks and the city, with the park being used as the main function; residential, commercial, business and cultural uses etc. are partial functions. In order for the park-based mixed use districts to be designated, the size of large urban parks and green spaces, as well as location, city function and condition of the peripheral areas all need to be considered. The necessity to examine the designated width of the park-based mixed use districts and the form of the peripheral area was also discussed. This research, which is based on investigative research results, suggests that further in-depth and comprehensive analysis of the actual condition of urban large parks and peripheral areas needs to be completed. Specialists and other interested parties, analysis and investigation on related plans and designs are also needed for the institutional practice.