• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10C
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• pp.995-1006
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• 2003

It is well know that in the wireless communication systems the transmitted signals can suffer from multipath fading due to the wave propagation characteristics and the obstacles over the paths, resulting in serious reduction in the power of the received signals. However, it is possible to take advantage of the inherent diversity imposed in the multipath reception if the underlying channel can be properly estimated. One of the diversity reception methods in this case is Rake processing. In this paper we study the Rake receivers for the direct-sequence spread-spectrum communication systems utilizing PN (pseudo noise) sequences to achieve spread spectrum. A conventional Rake receiver can use the finite-duration impulse (FIR) filter followed by the PN sequence demodulator, where the FIR filter coefficients are the reverse-ordered complex conjugate values of the fading channel impulse response estimates. Here, we propose a new Rake processing method by replacing the aforementioned PN code sequence with a new set of optimum demodulator coefficients. More specifically, the concept of the new optimum Rake processing is first introduced and then the optimum demodulator coefficients are theoretically derived. The performance obtained using the new optimum Rake processing is also calculated. The analytical results are verified by computer simulation. As a result, it is shown that the new optimum Rake processing method improves the MSE performance more than 10 dB over the conventional one using the fixed PN sequence demodulator. It is also shown that the new optimum Rake processing method improves the MSE performance about 10 dB over the Adaptive Correlator that performs the combining of the multipath components and PN demodulation concurrently. And finally, the MSE performance of the optimum Rake demodulator is very close to the MSE performance of OPSK demodulator under the AWGN channel.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.31-38
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• 2009

Purpose: This study was to evaluate corneal topography, contrast sensitivity and ocular response of a RGP, back surface aspherical contact lens compared with a spherical contact lens. Methods: A total 37 subjects were fitted with a spherical lens in right eye and an aspherical in the left eye and were evaluated for changes in corneal topography and contrast sensitivity over a 2-month period. Results: Thirty-four of 37 subjects completed the 2-month study. The corneal topography did not show differences between spherical and aspherical RGP lenses. The eyes fitted with the aspherical lenses demonstrated a greater reduction in contrast sensitivity compared with their spherical counterparts under photopic condition. Subjects preferred comfort and ocular responses provided by the spherical lens. Conclusions: Corneal topography when comparing spherical and back surface aspherical RGP lenses did not show any significant difference in the subjects. Spherical RGP lens yields better contrast sensitivity and preference than aspherical RGP lens at photopic condition. Further investigation of aberrations induced by contact lens design is warranted to explain the observed differences in visual performance.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.2
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• pp.195-201
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• 2011

Nardostachys chinensis;Anti-proliferation;Cell cycle arrest;Differentiation;U937 cells; This study was conducted to determine the analgesic effect of Sokyungwhalhyul-tang(SKWHT) using the model of peripheral neuropathic pain model. A model of neuropathic pain was made by ligating left 5th lumbar spinal nerve of rats. After 1 days, the extract of SKWHT was orally administered daily. Rats were divided into four groups; (1) Control group(n=6), (2) Experimental group I(SKWHT-OA1, 100 mg/kg, n=6), (3) Experimental group II(SKWHT-OA2, 300 mg/kg, n=6), (4) Experimental group III(SKWHT-OA3, 500 mg/kg, n=6). After that, we examined the withdrawl response of neuropathic rats legs by von Frey filament and Hot plate at pre, $1^{th}$, $4^{th}$, $7^{th}$, $14^{th}$, $21^{th}$ days after the induction of neuropathic pain. And also we examined c-fos, GOT, GPT and histological study of Liver at 21th days. von Frey filament and Hot plate were increase in experimental group I, II, III than Con. especially group III was most significantly analgesic effect than the other groups at $14^{th}$, $21^{th}$ days. In c-fos protein expression on spinal cord, group III was most significantly reduction immunoreactivity at $21^{th}$ days and in blood serum GOT & GPT levels and histologic finding of Liver in all experimental groups were no significant difference with Con at $21^{th}$ days. According to the above results, SKWHT(500 mg/kg) may have a significant analgesic effect on the neuropathic pain.

• Journal of the Korean Society of Radiology
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• v.4 no.2
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• pp.21-25
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• 2010

Recently, various semiconductor compounds as radiation detection material have been researched for a diagnostic x-ray detector application. In this paper, we have fabricated the CdS detecton sensor that has good photosensitivity and high x-ray absorption efficiency among other semiconductor compounds, and evaluated the application feasibility by investigating the detection properties about energy range of diagnostic x-ray generator. We have fabricated the line voltage selector(LCV) for a signal acquisition and quantities of CdS sensor, and designed the voltage detection circuit and rectifying circuit. Also, we have used a relative relation algorithm according to x-ray exposure condition, and fabricated the interface board with DAC controller. Performance evaluation was investigated by data processing using ANOVA program from voltage profile characteristics according to resistive change obtained by a tube voltage, tube current, and exposure time that is a exposure condition of x-ray generator. From experimental results, an error rates were reduced according to increasing of a tube voltage and tube current, and a good properties of 6%(at 90 kVp) and 0.4%(at 320 mA) ere showed. and coefficient of determination was 0.98 with relative relation of 1:1. The error rate according to x-ray exposure time showed exponential reduction because of delayed response velocity of CdS material, and the error rate has 2.3% at 320 msec. Finally, the error rate according to x-ray dose is below 10%, and a high relative relation was showed with coefficient of determination of 0.9898.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.305-312
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• 2007

Among many types of light rail transits (LRT), the rubber-tired automated guide-way transit (AGT) is prevalent in many countries due to its advantages such as good acceleration/deceleration performance, high climb capacity, and reduction of noise and vibration. However, AGT is generally powered by high-voltage electric power feeding system and it may cause electromagnetic interference (EMI) to measurement sensors. The fiber optic sensor system is free from EMI and has been successfully applied in many applications of civil engineering. Especially, fiber Bragg grating (FBG) sensors are the most widely used because of their excellent multiplexing capabilities. This paper investigates a prestressed concrete girder bridge in the Korean AGT test track using FBG based sensors to monitor the dynamic response at various vehicle speeds. The serviceability requirements provided in the specification are also compared against the measured results. The results show that the measured data from FBG based sensors are free from EMI though electric sensors are not, especially in the case of electric strain gauge. It is expected that the FBG sensing system can be effectively applied to the LRT railway bridges that suffered from EMI.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.415-422
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• 2010

Two leaf lettuces, chicory, endive, edible chrysanthemum, and pak-choi were hydroponically cultured under root restricted conditions in a deep flow technique system and their growth and nutritional values were investigated. Cylindrical plastic tubes with 100 mm height and diameters of 20, 25 or 30 mm were used for root restriction. Growth of all species was retarded by 25-95% as the roots zone was restricted. Pak-choi and edible chrysanthemum showed greater reduction in growth as compared with chicory and endive. Percent dry matter, C/N ratio, and contents of total ascorbic acid and total anthocyanin increased in the root restricted treatments. Contents of P and K decreased in the root restricted treatments, while contents of Mg, Fe, Mn, and Zn were not consistent among the tested species. Optimized root volumes to improve the nutritional values and to reduce the growth retardation varied depending on species of leafy vegetables. Tubes of ${\Phi}25mm{\times}100mm$ and ${\Phi}30mm{\times}100mm$ were suitable for chicory, endive and lettuce, and edible chrysanthemum and pak-choi, respectively. Results indicate that nutritional values of hydroponically-cultured leafy vegetables can be improved by root restriction.

• Journal of Nutrition and Health
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• v.47 no.2
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• pp.106-112
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• 2014

Purpose: This study was conducted in order to investigate the protective effects of ethanolic extract of Acanthopanax koreanum Nakai (AE) against carbon tetrachloride ($CCl_4$)-induced liver injury in rats. Methods: Male Sprague-Dawley rats were randomly divided into four groups in order to receive the following experimental diets with intraperitoneal injection of $CCl_4$ (2.0 mL/kg body weight, 20% solution 0.65 mL) for eight weeks (n = 8 per group): $CCl_4$ control (CON), $CCl_4$ + AE 1% (AE1), $CCl_4$ + AE 3% (AE3), or $CCl_4$ + acanthoic acid 0.037%, which is equivalent to AE 3% (AA). Results: Highest serum ALT activity and albumin level were observed in the $CCL_4$ control group, but showed a significant decrease by either AE or AA supplementation in a dose-dependent manner (p = 0.0063 and 0.0076, respectively). Both hemotoxylin and eosin staining and Masson's staining indicated remarkable prevention of $CCl_4$-induced liver damage in the AE3 group. $TNF{\alpha}$ and IL-6 production were significantly lowered in the AE treated groups, but not in the AA group (p = 0.0016 and p = 0.0002, respectively). The effects of AE3 were greater than those of AA for inflammation and liver toxicity biomarkers. Conclusion: Taken together, the results suggested that ethanolic extract of Acanthopanax koreanum Nakai provided hepatoprotective effects, leading to the reduction of inflammatory response. In addition, the effect of AE was superior to that of single compound AA.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.495-500
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• 1999

The carrageenans are linear, sulfated Polysaccharides extracted from various species of the Rhodophyta (marine red algae). The carrageenan backbone is based on a repeating disaccharide sequence of $\beta$-D-galactopyranose residues linked glycosidically through position 1 and 3, and $\alpha$-D-galactopyranose residues linked glycosidically through position 1 and 4. Carrageenans are typical food polysaccharides in that food applications overwhelmingly dominate their end uses. Other applications, hewer, including cosmetics, pharmaceuticals, industrial suspensions and paints are also of importance But because of its high degree of gelling and viscosity with low solubility, carrageenan is limited to use beyond $0.03\%$ as food additives. Response Surface Methodology was applied for optimizing the processing parameters of ultrasound treatment in order to produce low-molecular-weight carrageenan. The use of ultrasound significantly reduced viscosity of $\lambda$-carrageenan solutions. Optimal parameters for ultrasound reduction of carrageenan molecular weight were: temperature, $10^{\circ}C$; ultrasound intensity, 121.64 $W/cm^2$ ; tarrageenan concentration, $2\%$; treatment time, 40 min. As the gel permeation chromatogram of dextran standards (M.W.= 500,000 ; 260,000 ; 167,000 ; 71,400 ; 42,000) and ultrsound treated carrageenan, the molecular weight of ultrasound treated carrageenan were approximately 200,000 (peak 1) and 60,000 (peak 2), respectively.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.551-558
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• 2013

Ethanol extracts from Rhododendrom brachycarpum and Abies koreana were investigated for their anti-allergic activities using RBL-2H3 cell line. After treatment with ethanol extracts of various concentrations on the immune response induced mast cell by concanavalin A (Con A), the expressions of cytokine interleukin-4 (IL-4), interleukin-13 (IL-13) were determined by using RT-PCR and the degranulation of mast cells was determined by measuring ${\beta}$-hexosaminidase release. Expression level of IL-4 was decreased by the extract from Rhododendrom brachycarpum in $10^{-7}$, $10^{-5}$ and $10^{-3}%$ concentrations. Expression level of IL-13 was also decreased by both extracts. ${\beta}$-Hexosaminidase release by RBL-2H3 cells was inhibited at the $10^{-5}$ and $10^{-3}%$ concentration of extracts from Rhododendrom brachycarpum and Abies koreana, respectively. These results demonstrate that ethanol extracts of Rhododendron brachycarpum and Abies koreana exert anti-allergic effects by regulating the reduction of IL-4 and IL-13 genes expression and also the secretion of ${\beta}$-hexosaminidase.

• Journal of Korean Medical Science
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• v.33 no.51
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• pp.325.1-325.10
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• 2018

Background: To evaluate survival outcomes and prognostic factors for overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) who received sunitinib (SU) and pazopanib (PZ) as first-line therapy in real-world Korean clinical practice. Methods: Data of 554 patients with mRCC who received SU or PZ at eight institutions between 2012 and 2016 were retrospectively reviewed. Based on the targeted therapy, the patients were divided into SU (n = 293) or PZ (n = 261) groups, and the clinicopathological variables and survival rates of the two groups were compared. A multivariable Cox proportional hazard model was used to determine the prognostic factors for OS. Results: The median follow-up was 16.4 months (interquartile range, 8.3-31.3). Patients in the PZ group were older, and no significant difference was observed in the performance status (PS) between the two groups. In the SU group, the dose reduction rate was higher and the incidence of grade 3 toxicity was more frequent. The objective response rates were comparable between the two groups (SU, 32.1% vs. PZ, 36.4%). OS did not differ significantly between the two groups (SU, 36.5 months vs. PZ, 40.2 months; log-rank, P = 0.955). Body mass index, Eastern Cooperative Oncology Group PS > 2, synchronous metastasis, poor Heng risk criteria, and liver and bone metastases were associated with a shorter OS. Conclusion: Our real-world data of Korean patients with mRCC suggested that SU and PZ had similar efficacies as first-line therapy for mRCC. However, PZ was better tolerated than SU in Korean patients.