• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.393-396
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• 2003

Conventional method for designing and installing anechoic chambers is to utilize porous wedges for the sound absorbers. As cutoff frequency lowers down such as 63Hz or 50Hz, the corresponding long wedges diminish the free field area of the chamber. In this study, a new broadband compact absorber(BCA) is introduced which absorbs acoustic energy down to 50Hz. Most prominent is that it measures only 250mm thick. A freely vibrating panel between the non-fibrous absorbers allows tuned absorption at the low frequency region in addition to the high frequency absorption resulted from the conventional absorber installed at the front. Standing waves at low frequency range are suppressed as the BCA modules which are tuned to the corresponding modes absorb sound energy effectively, resulting in anechoic condition. Not only the low frequency performances, but the high frequency absorption is measured to meet adequate conditions for the anechoic chamber. Realized BCA chambers are presented.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.1
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• pp.11-24
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• 2019

This paper investigates the performance comparison of a Terahertz (THz) communications for a single-carrier and a multi-carrier single antenna point-to-point communication system. The multi-carrier system and single carrier system consider the orthogonal frequency division multiplexing (OFDM) and the minimum mean square error linear equalizer (MMSE-LE), respectively. We compare the frame-error-rate (FER) and throughput performance of both the systems for a THz communication environment with the carrier frequency of 300GHz and the tapped delay line (TDL) channel models described in 3GPP. It is observed from the simulation results that the OFDM systems outperform the MMSE-LE for various configurations.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.292-292
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• 2005

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.122-126
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• 2002

A feeding trial was conducted to determine compensatory growth of juvenile olive flounder in the spring. Five treatments of fish with 3 replicates were prepared: the control group fish (C) fed twice daily for 8 weeks, the Sl, S2, S3 and S4 fish fed for 7, 6, 5 and 4 weeks after 1, 2, 3 and 4 weeks of starvation, respectively. Survival of olive flounder was not significantly different among treatments. Weight gain of flounder in S2 was significantly (P<0.05) higher than that of fish in S3 or S4, but not significantly different from that of fish in C or Sl. The poorest weight gain was observed in fish of S4 treatment. Specific growth rate (SGR) for flounder in S2 was significantly (P<0.05) higher than that for fish in C or S4, but not significantly different from that of fish in Sl or S3. Feed intake (g/fish) was proportional to duration of days of feeding except for flounder in S2, but not significantly different among C, Sl or S2. Feed efficiency ratio (FER) and protein efficiency ratio (PER) for flounder in S2 were significantly (P<0.05) higher than for fish in C, but not significantly different from those for fish in Sl, S3 or S4. Hepatosomatic index (HSI) and condition factor (CF) for flounder in Sl, S3 and S4 were not significantly different from those for fish in C, but significantly (P<0.05) lower than S2 except for CF in Sl at the end of the experiment. Proximate composition of the whole body of flounder was not significantly different among treatments. In considering results of the experiment, juvenile olive flounder achieved compensatory growth when properly fed after starved up to 2 weeks in the spring. Compensatory growth of fish was supported by improvement in SGR, FER and PER in fish starved.

• Herbal Formula Science
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• v.21 no.2
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• pp.44-52
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• 2013

Objectives : Samhwangsasim-tang (SST), Hwangryeonhaedok-tang (HHT), Ukgan-san (UGS), Onjunghwadam-hwan (OHH) and Samul-tang (SMT) have been used for the treatment of various diseases. This study was performed to compare the anti-obesity effects of 5 herbal formulas in high fat diet-(HFD) induced obese mice. Methods : The mice were randomly divided into seven groups that were fed a normal diet (ND), a HFD, a HFD plus SST (HFD + SST), a HFD plus HHT (HFD + HHT), a HFD plus UGS (HFD + UGS), a HFD plus OHH (HFD + OHH), or HFD plus SMT (HFD + SMT) at 300 mg/kg/day for 7 weeks. All groups were assayed for body weights, food efficiency ratio (FER), final liver and fat weight and blood biochemical parameters. Results : The increased body weights, food efficiency ratio (FER), and serum total triglyceride were decreased in HFD + OHH group relative to the same measurements in HFD group. Furthermore, the HFD + SST group significantly reduced FER, liver and abdominal subcutaneous fat weight gains, and serum total triglyceride, whereas HDL-cholesterol level was increased compared to HFD group. Conclusions : These results suggested that HFD + OHH and HFD + SST exert anti-obesity effects in HFD-induced obese mice.

• Journal of Nutrition and Health
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• v.26 no.1
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• pp.21-33
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• 1993

This balance study was performed to investigate nutritional effects of guar gum and calcium supplement for 8 weeks. 36 male rate of Sprague-Dawley strain weighing 50g were blocked into six groups : 5CN, 5GN, 5CS, 5GS, FFN, 10GN. Food intake, body weight gains, FER, PER, bioavailabity of energy, protein, fat, Ca and P, and Ca & P content of femur and kidney was measured. The results obtained in this study were summarized as follows: (1) Feed intake, weight gains, FER, PER and bioavailabilities of protein and P and the contents of Ca & P in femur of 5GB were significantly higher than 5CN and 5CS (p<0.05) but was not significant different with those 5GN. Fat bioavailabilities of 5GS was significantly lower than 5CN and 5GN (p<0.05) but was not significant different with those of 5CS. Ca contents of kidney of 5GS was significantly higher than 5CN and 5GN(p<0.05) but was not significant different with those of 5SC. (2) According to guar gum levels feed intake. FER and PER were not sifgnificantly different among groups but body weight gains, bioavailabilities of energy, protein, fat and Ca, Ca & P content of femur was significantly decreased (p<0.05). Bioavailabilities of P was significantly increased according to the guar gum levels (p<0.05). Ca contents in Kidney of 10GN was significantly higher those of 5GN(p<0.05) but P contents in kidney was not significant difference by guar gum levels. Therefore 5% supplemental guar gum in diet of obese man and diebetics could be recommended. But it should be careful in using 10% guar gum in diet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2124-2148
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• 2017

Accurate facial expression recognition (FER) requires reliable signal filtering and the effective feature extraction. Considering these requirements, this paper presents a novel approach for FER which is robust to noise. The main contributions of this work are: First, to preserve texture details in facial expression images and remove image noise, we improved the anisotropic diffusion filter by adjusting the diffusion coefficient according to two factors, namely, the gray value difference between the object and the background and the gradient magnitude of object. The improved filter can effectively distinguish facial muscle deformation and facial noise in face images. Second, to further improve robustness, we propose a new feature descriptor based on a combination of the Histogram of Oriented Gradients with the Canny operator (Canny-HOG) which can represent the precise deformation of eyes, eyebrows and lips for FER. Third, Canny-HOG's block and cell sizes are adjusted to reduce feature dimensionality and make the classifier less prone to overfitting. Our method was tested on images from the JAFFE and CK databases. Experimental results in L-O-Sam-O and L-O-Sub-O modes demonstrated the effectiveness of the proposed method. Meanwhile, the recognition rate of this method is not significantly affected in the presence of Gaussian noise and salt-and-pepper noise conditions.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.441-445
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• 2009

Effect of temperature on membrane degradation in PEMFCs was studied. After cell operation at different temperatures($60{\sim}90^{\circ}C$) under accelerating degradation conditions(OCV, anode dry, cathode RH 65%) for 144 h, cell performance decreased from 12 to 35%. The results of FER in effluent water showed that this decrease in cell performance was caused by membrane degradation by the attack of $H_2O_2$ or oxygen radicals(${\cdot}OH$, $HO_2{\cdot}$) and that resulted in increase in gas crossover for radical formation. Radical formation on the electrode was confirmed by ESR. Activation energy of 66.2 kJ/mol was obtained by Arrhenius plot used to analyze the effect of temperature on membrane degradation. Increase of cell temperature enhanced gas crossover rate, radical formation rate and membrane degradation rate.

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.65-76
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• 2003

The analysis of cow body parameters is important to provide some useful information fur cow management and cow evaluation. Present methods give many stresses to cows because they are invasive and constrain cow postures during measurement of body parameters. This study was conducted to develop the stereo vision system fur non-invasive analysis of cow body features. Body feature parameters of 16 heads at two farms(A, B) were measured using scales and nineteen stereo images of them with walking postures were captured under outdoor illumination. In this study, the camera calibration and inverse perspective transformation technique was established fer the stereo vision system. Two calibration results were presented for farm A and fm B, respectively because setup distances from camera to cow were 510 cm at farm A and 630cm at farm B. Calibration error values fer the stereo vision system were within 2 cm for farm A and less than 4.9 cm for farm B. Eleven feature points of cow body were extracted on stereo images interactively and five assistant points were determined by computer program. 3D world coordinates for these 15 points were calculated by computer program and also used for calculation of cow body parameters such as withers height. pelvic arch height. body length. slope body length. chest depth and chest width. Measured errors for body parameters were less than 10% for most cows. For a few cow. measured errors for slope body length and chest width were more than 10% due to searching errors fer their feature points at inside-body positions. Equation for chest girth estimated by chest depth and chest width was presented. Maximum of estimated error fur chest girth was within 10% of real values and mean value of estimated error was 8.2cm. The analysis of cow body parameters using stereo vision system were successful although body shape on the binocular stereo image was distorted due to cow movements.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.791-795
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• 1996

Toha-jeot(salt-fermented Toha shrimp) is a traditional fermented food in Korea. Toha-jeot is fermented for 90 days at $4\pm1^{\circ}C$ with 20%(w/w) salt per live Toha shrimp. We expect that the high polymer chitin of Toha shell will be hydrolyzed by chitinase during the fermentation of Toha-jeot and that the low molecular weight of chitin oligosaccharides will be produced. We experimented 7 samples which were taken at the interval of 15 days during the total 90 days of fermentation. We also measured molecular weight of Toha-chitin, viscosity and molecular weight distribution of chitin during fermentation of Toha-jeot, The decrease of viscosity and average molecular weight of chitin were observed as fermentation proceeds. Chitin oligosaccharide with $10^3molecular$ weight was low until 60 days fer-mentation. However, chitin oligosaccharide with $10^3molecular$ weight was high after 75 days fer-mentation. And chitin oligosaccharide with $10^2molecular$ weight were observed after fermenting Toha for 75 days and 90 days, but chitin oligosaccharide with 10'molecular weight did not appear up to 60 days of fermentation.ation.