• Nuclear Engineering and Technology
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• v.21 no.1
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• pp.40-47
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• 1989

For the effective design of a beam forming structure of the negative-ion-based neutral beam injector, a computer program based on a particle simulation model is developed for the calculation of charged particle motions in the electrostatic fields. The motions of negative ions inside the acceleration tube of a multiple-aperture triode are computed at finite time steps. The electrostatic potentials are obtained from the Poisson's equation by the finite difference method. The successive overrelaxation method is used to solve the matrix equation. The particle and force weighting methods are used on a cloud-in-cell model. The optimum design of the beam forming structure has been studied by using this computer code for the various conditions of elctrodes. The effects of the acceleration-deceleration gap distance, the thickness of the deceleration electrode and the shape of the acceleration electrode on beam trajectories are exmined to find the minimum beam divergence. Some numerical illustrations are presented for the particle movements at finite time steps in the beam forming tubes. It is found in this particle simulation modelling that the shape of the acceleration electrode is the most significant factor of beam divergence.

• Journal of the Korean association of regional geographers
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• v.13 no.2
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• pp.143-155
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• 2007

There are many conflicts or interests among various stakeholders on the development of the coastal area. The integrated methodology, which is reflective of physical conditions, socio-economic circumstances, and people's sense of values, is thus needed to solve the problems. In this study, geographical information systems(GIS) and analytic hierarchy process(AHP) that arc one of multi-criteria analysis methodologies are loosely coupled to develop better analytic procedures for coastal assessment. Socio-economic and environmental parameters of the study area, Hampyung Bay area, are converted to a GIS system-applicable format, while AHP is used to assess the relative importance level of each parameter by calculating weighting factors. After standardizing and rasterizing spatial data from various sources. the weighting factors are applied to produce the layers for each parameter. Map algebra and overlay analyses are used to create the final layer according to the decision making logic or model proposed here. Cell values of that layer could be considered as spatial alternatives. In addition to this finding, the flexibility with the weighing factors enable decision-makers to understand the procedures and alternatives in relevance with selective strategies for coastal management.

• The Journal of Korean Obstetrics and Gynecology
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• v.18 no.4
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• pp.85-105
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• 2005

Purpose : Investigate the effects of Chungganhaewooltang(CHT) on immobilization-stress or cold-stress in C576BL/6J mice. Methods : Male C57BL/6J 30 mice of weighting 18${\pm}$2g, were divided into sixs groups including the immobilization-stress group(5heads), after immobilization-stress CHT oral administration(500mg/kg) groups(5heads), cold-stress group(5heads) and after cold-stress CHT oral administration(500mg/kg) groups(5heads). then we observed changes in the serum histamine and corticosterone level and changes immune system Results : Immobilization-stress or cold-stress increased the serum level of histamine and corticosterone. CHT decreased the serum level of histamine and corticosterone increased by cold-stress. CHT inhibited the release of histamine from mast cells at the concentration of 0.1 mg/ml. In addition, immobilization-stress or cold-stress decreased the cell viability of murine thymocytes and splenocytes. CHT increased the cell viability of thymocytes decreased by immobilization-stress or cold-stress, but did not affect the cell viability of splenocytes decreased by immobilization-stress or cold-stress. Also immobilization-stress or cold-stress increased DNA fragmentation of thymocytes and splenocytes. CHT decreased DNA fragmentation of thymocytes increased by immobilization-stress or cold-stress, but did not affect DNA fragmentation of splenocytes increased by immobilization-stress or cold-stress. Immobilization-stress increased the population of thymic $CD4^+$ cells. CHT decreased the population of thymic $CD4^+$ cells increased by immobolization-stress. Immobilization-stress or cold-stress decreased the population of $B220^+$ cells and increased the population of $thy1^+$ cells. CHT decreased the population of $thy1^+$ cells increased by immobilization-stress or cold-stress. Immobilization-stress or cold-stress increased the population of splenic $CD4^+$ cells and $CD8^+$ cells. CHT decreased the population of splenic $CD4^+$ cells increased by immobolization-stress or cold-stress. Immobilization-stress or cold-stress decreased the production of ${\gamma}-interferon$(IFN) interleukin(IL)-2 and IL-4. CHT enhanced the production of ${\gamma}-IFN$ decreased by immobilization-stress or cold-stress but did not affect the production of IL-2 and IL-4 decreased by immobilization-stress or cold-stress. Furthermore, Immobilization- stress or cold-stress decreased the phagocytic activity of peritoneal macrophages and the production of nitric oxide. CHT enhanced the phagocytic activity and nitric oxide production decreased by cold-stress. Conclusion : CHT may be useful for the prevention and treatment of stress via suppression of serum histamine and corticosterone level and enhancement of immune response.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.9-16
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• 2012

In order to extend cell coverage and to cope with shadow areas, a relay-assisted wireless communications system has been widely studied. In this paper, we propose new equalization method for single carrier (SC) frequency domain equalizer (FDE) in amplify-and-forward (AF) relaying multi-path networks to improve the performance at shadow areas. The performance of SC-FDE system in 3-slot based multi-path networks can be improved considerably with the diversity gain which we obtain by equalizing the combined signal from relays by means of the minimum mean square error (MMSE) criteria. We find the weighting coefficients of maximum ratio combining (MRC) and the tap coefficients of MMSE equalizer for SC-FDE in AF relaying multi-path networks. Simulation results show that the proposed system considerably outperforms the conventional SC-FDE system.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.133-141
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• 2000

Purpose : The purpose of this study is to estabilish clinical guidance of microvascular anastomosis in diabetic patients. This study was performed with experimental microvascular anastomosis in streptozotocin induced diabetic rats and observed histopathologic change and endohelial healing process. Materials and Methods : 70 Sprague-Dawley rats, weighting 200 to 250grams, were used for the experiment. 35 induced diabetic rats with streptozotocin and 35 control group were selected. After end-to-end carotid artery microvascular anastomosis was done, the experimental rats were sacrificed at different time interval (1st day, 3rd day, 1st week, 2nd, 4th, 6th and 8th week) for histologic examination. Light microscope observation was used in this study. Results : 1. Histopathologic changes are nearly the same healing process in two groups. But period of tissue reaction was faster in the control than diabetic group. 2. In endotheliall healing, control group started at 1 week after and completed at 4 weeks after, but diabetic group was observed partially at 4 weeks after and complete healing was not observed still at 8 weeks after. 3. In subintimal hyperplasia, control group was observed at 6 weeks after but diabetic group was observed at 6 weeks after and partially at 8 weeks after. 4. All groups showed severe inflammatory response in the early period. This respond is decreased at 2 weeks after in control group but still remained at 8 weeks after in the diabetic group. 5. In media, inflammatory response and degeneration were observed in early period. Regeneration of smooth muscle cell was observed at 1 week after in control group but 4 weeks after in the diabetic group. Conclusions : As the results of study, it could be thought that vascular regeneration process was not failured but delayed in the diabetes. It was considered that diabetes mellitus was not absolute contraindication of microvascular anastomosis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.61-66
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• 2005

This paper describes a 10-bit 210MHz CMOS current-mode Digital-to-Analog Converter (DAC) consisting of 6 bit MSB current cell matrix Sub-DAC, 2 bit mSB unary current source Sub-DAC, and 2 bit LSB binary weighting Sub-DAC for Wireless LAN application. A new deglitch circuit is proposed to control a crossing point of signals and minimize a glitch energy. The proposed 10-bit CMOS current mode DAC was designed by a $0.35{\mu}m$ CMOS double-poly four-metal technology rate of 210MHz, DNL/INL of ${\pm}0.7LSB/{\pm}1.1LSB$, a glitch energy of $76pV{\cdot}sec$, a SNR of 50dB, a SFDR of 53dB at 200MHz sampling clock and power dissipation of 83mW at 3.3V

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.3
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• pp.288-300
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• 2002

In this paper, a novel method of equalization of RF transceivers is suggested for MIMO(Multiple Input Multiple Output) antenna actively studied for high speed data transmission in the recent IMT-2000 system. The core of suggestion is in equalizing the transfer characteristics of multiple transceivers using feedback and memory during the predefined calibration time. This makes it possible to weight the signals in the intermediate frequency, which is easier in the application of recently developed DoA(Direction of Arrival) algorithms. In addition, the time varying optimum cell formation according to traffic is feasible by antenna beam-forming based on the DoA information. The suggested method of equalizing multiple transceivers are successfully verified using envelope simulation. two outputs. This paper is concerned with the diagnosis of multiple crosstalk-faults in OSM. As the network size becomes larger in these days, the convent.
nal diagnosis methods based on tests and simulation be.
me inefficient, or even more impractical. We propose a simple and easily implementable alg？ithm for detection and isolation of the multiple crosstalk-faults in OSM. Specifically, we develop an algorithm for isolation of the source fault in switc.
ng elements whenever the multiple crosstalk-faults are.
etected in OSM. The proposed algorithm is illustrated by an example of 16$\times$16 OSM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.698-707
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• 1998

For inverse scattering problems reconstructing cross-sectional permittivity distributions of dielectric cylinders, the angular spectral inverse technique using the moment method with pulse basis function suffers from large reconstruction error even if very small noise due to requiring the higher spectral informations on the larger cross-section of the cylinder. To reduce the number of higher-order spectra, this paper presents an improved inverse technique in angular spectral domain applying the moment procedure with a series-expansion basis function for the induced field in each enlarged cross-sectional cell. By choosing adequate spectra and averaging over the enlarged cells with a suitable weighting function, the reconstruction profiles reveal fine enough to suppress the noise effect significantly.

• Journal of Nutrition and Health
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• v.34 no.3
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• pp.271-284
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• 2001

This study was performed to investigate the effects of dried powders and water extracts of Paecilomyces tenuipes(P. tenuipes) and Cordyceps militaris(C. militaris) on lipid metabolism, lipid peroxidation and antioxidative capacity and immune status in rats. Thirty-five male Sprague-Dawley rats weighting 195$\pm$21g were grouped into five according to body weight. Ratw were raised for four weeks with diet containing either 4%, 2%(w/w) of dried P. tenuipes powders(TP-4, TP-2) or water extracts from equal amounts of each 4% P. tenuipes and C. militaris powder(TE-4, ME-4). Food intake, weight gain of all groups were not significantly different from those of control group. Lipid metabolism in general was not significantly different among all the groups. However both dried P. tenuipes powder lowered plasma cholesterol level slightly, water extract groups showed tendency of higher plasma HDL-cholesterol and lower liver cholesterol levels than control. Plasma and liver thiobarbituric acid reactive substance(TBARS) concentrations of all the experimental groups were lower than control group. Red blood cell(RBC) and liver superoxide dismutase(SOD) activities were not generally different among all groups. Liver xanthine oxidase(XOD) activities of all groups were tended to be lower than control group. Proliferation of aplenocytes induced by mitogens, concanavalin A and lipopolysaccharide, were increased in TP-2 group. The TP-4 group showed increased CD8 T cells and MHC class II expression without changes in CD4 T cells, B cells and G/M ratio, suggesting activated cytotoxic T cell activity in vivo. Increase of G/M ratio but not of MHC class II in TP-2 group indicated the possible acute inflammatory reaction by the ingested substances in gastrointestinal tract. ME-4 group showed enhanced cellular immunity without vigorous changes of immune parameters in brief periods. In conclusion, both P. tenuipes and C. militaris stimulated antioxidant capacity and immune status in rats. Among groups, water extract of C. militaris was most effective in both capacities, though dried powder of P. tenuipes at 2% dietary level was more effective in antioxidant activity, as various results by different strains were observed.(Korean J Nutrition 34(3) : 271~284, 2001)

• The Journal of Korean Obstetrics and Gynecology
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• v.18 no.3
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• pp.51-66
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• 2005

Purpose : Investigate the effects of Haeganjeon water extract (HGJ) on immobilization-stress or cold-stress in C57BL/6J mice. Methods : Male C57BL/6J 30 mice of weighting 18${\pm}$2g, were divided into sixs groups including the immobilization-stress group(5heads), after immobilization-stress HGJ oral administration(500mg/kg) groups(5heads), cold-stress group(5heads) and after cold-stress HGJ oral administration(500mg/kg) groups(5heads). then we observed changes in the serum histamine and corticosterone level and changes immune system. Results : HGJ decreased the serum level of histamine and corticosterone increased by immobilization-stress or cold-stress. HGJ inhibited the release of histamine from mast cells. In addition, HGJ enhanced the cell viability of thymocytes decreased by immobilization-stress or cold-stress and decreased DNA fragmentation of thymocytes increased by immobilization- stress or cold-stress. Also, HGJ increased the cell viability of splenocytes decreased by cold-stress and decreased DNA fragmentation of splenocytes increased by cold-stress. HGJ decreased the population of thymic CD4+ cells increased by immobolization-stress. HGJ increased the population of B220+ cells decreased by immobilization-stress and decreased the population of Thy1+ cells increased by immobilization-stress. Also, HGJ decreased the population of splenic CD4+ cells increased by immobolization-stress. HGJ enhanced the production of ${\gamma}-interferon$ decreased by immobilization-stress or cold-stress and increased the production of interleukin-4 decreased by immobilization-stress. Furthermore, HGJ enhanced the phagocytic activity decreased by immobilization-stress or cold-stress and enhanced the level of nitric oxide decreased by immobilization-stress or cold-stress. Conclusion : HGJ may be useful for the prevention and treatment of stress via suppression of serum histamine and corticosterone level and enhancement of immune response.