• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.5 s.335
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• pp.55-62
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• 2005

In this paper, we propose an efficient symbol detection algorithm for space-frequency OFDM (SF-OFDM) transmit diversity scheme and present the implementation results of the SF-OFDM WLAN baseband processor with the proposed algorithm. When the number of sub-carriers in SF-OFDM scheme is small, the interference between adjacent sub-carriers may be generated. The proposed algorithm eliminates this interference in a parallel manner and obtains a considerable performance improvement over the conventional detection algorithm. The bit error rate (BER) performance of the proposed detection algorithm is evaluated by the simulation. In the case of 2 transmit and 2 receive antennas, at $BER=10^{-4}$ the proposed algorithm obtains about 3 dB gain over the conventional detection algorithm. The packet error rate (PER), link throughput, and coverage performance of the SF-OFDM WLAN with the proposed detection algorithm are also estimated. For the target throughput at $80\%$ of the peak data rate, the SF-OFDM WLAN achieves the average SNR gain of about 5.95 dB and the average coverage gain of 3.98 meter. The SF-OFDM WLAN baseband processor with the proposed algorithm was designed in a hardware description language and synthesized to gate-level circuits using 0.18um 1.8V CMOS standard cell library. With the division-free architecture, the total logic gate count for the processor is 945K. The real-time operation is verified and evaluated using a FPGA test system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.27-33
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• 1979

In early August 1978, a huge red tide occurred off Chilcheon Is, , at the mouth of Jinhae Bay. It expanded rapidly into the central part and then soon covered all the bay except the innermost part of the bay. After staying for a week it disappeared, and thereafter several small scale red tides partially occurred and disappeared untill the end of August. It differed from the red tides hitherto recorded from this bay in respect of the dominant plankter, the geographical extent and the severe damaging effect to local oyster resources. During the red tide period, nevertheless, no oyster damage was found. In September, however, oyster mortailty was found from all rafts and longlines in the bay. Except the inner most part of the bay the oyster farms were completely destroyed. Of the oyster Production in the winter 1978, $96\%$ of an estimated yield of 5,879 tons (shucked meat) was lost and it was estimated to be 2,275 million won, equivalent to $US\$$ 4.55 million. The dominant species was a dinoflagellate, Ceratium fusus and it constituted about $45\%$ of the total phytoplankton. Cell count showed $7.0\times10^4\;cells/\iota$ and chlorophyll-a, $50mg/m^3$ during red tide peak. No oxygen was found ill the bottom waters in September. Sulphides in bottom waters and in the superficial mud increased to 15 and 8-fold respectively in September compared with July ana August. Precipitation from January to May of 1978 was about a third in comparison with the past ten years average but rainfall ill June was two and half-fold more than normal year, and thereafter drought persisited till September Air and water temperatures were also higher, and sunny days continued for a long time without strong winds. Therefore, water was calm for a long time after the red tide extinguished. The result indicated that the occurrence of the Ceratium red tide occurred in that year which was characterized by the combination of the formation of almost anoxic bottom water before the red tide occurrence, high air temperature and the calmness after a great quantity of rainfall in June. The mass mortality of oysters was presumed not to be directly related with the red tide but with the depression of dissolved oxygen in the environmental waters at the bottom due to settling of the red tide organisms.

• Food Science and Preservation
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• v.23 no.3
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• pp.445-452
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• 2016

In this study, physicochemical properties of acorn flour was investigated, and characteristics of the Jeung-pyun dough added with the acorn flour at various concentrations were evaluated after storage at -$18^{\circ}C$ for 4 weeks and fermentation. Total polyphenolic content, electron donating ability (EDA) of 0.5%, gelatinization onset temperature (To), gelatinization peak temperature (Tp), and gelatinization conclusion temperature (Tc) of acorn flour were 3,525.12 mg%, 16.71%, $68.41^{\circ}C$, $73.83^{\circ}C$, and $82.96^{\circ}C$, respectively. These all values were increased in the Jeung-pyun dough possibly due to addition of the acorn flour. The yeast count was not affected by the addition levels of acorn flour and the frozen storage period before fermentation. The amount of carbon dioxide gas evolved from Jeung-pyun dough during fermentation was significantly changed with the concentration of acorn flour, but it was negligible. The Jeung-pyun added with 6% acorn flour showed an small increase in the amount of carbon dioxide after frozen storage of 1 wk and fermentation. The pH of the fermented Jeung-pyun samples decreased along with the increasing storage period as well as the increasing acorn flour content, ranging from 4.21 to 5.34. Therefore, the frozen Jeung-pyun dough containing 6~15% of acorn flour and stored for 3 weeks was the most desirable among all the tested samples in this study.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.62-70
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• 2011

Nowadays image sensor is an essential component in many multimedia devices, and it is covered by a color filter array to filter out specific color components at each pixel. We need a certain algorithm to combine those color components reconstructed a full color image from incomplete color samples output from an image sensor, which is called a demosaicking process. Most existing demosaicking algorithms are developed for ideal image sensors, but they do not work well for the practical cases because of dissimilar characteristics of each sensor. In this paper, we propose a new demosaicking algorithm in which the color filter characteristics are fully utilized to generate a good image. To demonstrate significance of our algorithm, we used a commerically available sensor, CBN385B, which is a sort of Honeycomb-style CFA(Color Filter Array) CCD image sensor. As a performance metric of the algorithm, PSNR(Peak Signal to Noise Ratio) and RGB distribution of the output image are used. We first implemented our algorithm in C-language for simulation on various input images. As a result, we could obtain much enhanced images whose PSNR was improved by 4~8 dB compared to the commonly idealized approaches, and we also could remove the inclined red property which was an unique characteristics of the image sensor(CBN385B).Then we implemented it in hardware to overcome its problem of computational complexity which made it operate slow in software. The hardware was verified on Spartan-3E FPGA(Field Programable Gate Array) to give almost the same performance as software, but in much faster execution time. The total logic gate count is 45K, and it handles 25 image frmaes per second.

• Clinical and Experimental Pediatrics
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• v.54 no.8
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• pp.340-344
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• 2011

Purpose: Brain natriuretic peptide (BNP) has been considered a biochemical marker for myocarditis in Kawasaki disease. We performed this study to determine its quantitative significance. Methods: We attempted to correlate log-transformed BNP concentrations (log-BNP) and clinical, laboratory, and echocardiographic variables in 81 children with Kawasaki disease. Stepwise multiple linear regression analysis was used to determine the variables independently associated with log-BNP concentration. Results: Serum C-reactive protein level (P<0.0001), serum alanine aminotransferase concentration (P =0.0032), white blood cell count (P=0.0030), and left ventricular mass index (P=0.0024) were positively related with log-BNP, and hemoglobin level (P<0.0001), serum albumin level (P<0.0001), $Na^+$ concentrations (P<0.0001), left ventricular fractional shortening (P=0.0080), and peak early diastolic tissue velocity of the left ventricular basal lateral segment (P=0.0045) were negatively related to the log-BNP concentration. Multiple regression analysis showed that serum albumin concentration ($R_2$=0.31, P=0.0098) and left ventricular mass index ($R_2$=0.09, P=0.0004) were significantly associated with the log-BNP concentration. Conclusion: Elevated BNP levels during the acute phase of Kawasaki disease may be attributable to cardiac dysfunction associated with the increase in left ventricular mass, and log-BNP concentration may be a quantitative biochemical marker of myocarditis in Kawasaki disease.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6905-6911
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• 2013

Background: Breast cancer (BC) is the top cancer among women worldwide and the most frequent malignancy among Iranian women over the past few decades. The increasing trend and high mortality rate of BC in the developing world necessitates studies concentrating on its characteristics in countries in Asia. The current study focused on clinical and histopathological features of BC among Iranian females. Materials and Methods: This retrospective study involved 714 Iranian patients with histopathologically proven BC undergoing resection of primary tumours and axillary clearance. Demographic, clinical and histopathological data were obtained and studied between ten year age groups (${\leq}40$ years, 41-50 years, 51-60 years, 61-70 years, and ${\leq}71$ years) in four chronologic phases from 1994-2009. Results: Mean age of patients was $49.4{\pm}13.1$ years. Most of cases (33.2%) were in 41-50 group. Mean size of primary tumors was $3.94{\pm}2.47$ cm and 87.1% of cases had infiltrative ductal carcinoma. Modified radical mastectomy was the most common method of surgery carried out (48.8%). Some 57.1% of tumors were in pT2 and tumor size decreased significantly during the period (p<0.05). The most common BC stage was llla (27%). Lower BC stages (0 and 1) constituted 13.9% of the diagnosed tumors. Our series of patients aged ${\leq}40$ had larger tumors (mean $4.73{\pm}3.02$ cm) compared to older age groups (p=0.003). Lower stages (0 and I) were more frequent among the oldest patients while nearly 50% of patients aged ${\leq}40$ had tumor stage III. We also observed a significant decreasing trend in the mean LN count (p<0.05) and blood vessel invasion (p=0.023) from younger to older age groups. Conclusions: More aggressive disease for younger age groups, earlier peak incidence age and high rate of advanced BC at the time of diagnosis among Iranian women, were the main findings of this study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.427-436
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• 2016

In general, QRS duration represent a distance of Q start and S end point. However, since criteria of QRS duration are vague and Q, S point is not detected accurately, arrhythmia classification performance can be reduced. In this paper, we propose extraction of Q, S start and end point RS feature based on phase transition tracking method after we detected R wave that is large peak of electrocardiogram(ECG) signal. For this purpose, we detected R wave, from noise-free ECG signal through the preprocessing method. Also, we classified QRS pattern through differentiation value of ECG signal and extracted Q, S start and end point by tracking direction and count of phase based on R wave. The performance of R wave detection is evaluated by using 48 record of MIT-BIH arrhythmia database. The achieved scores indicate the average detection rate of 99.60%. PVC classification is evaluated by using 9 record of MIT-BIH arrhythmia database that included over 30 premature ventricular contraction(PVC). The achieved scores indicate the average detection rate of 94.12% in PVC.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.959-972
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• 2017

In evaluation of blast-induced vibration, peak particle velocity (PPV) is generally calculated by using attenuation relation curve. Calculated velocity is compared with the value in legal requirements or the standards to determine the stability. Attenuation relation curve varies depending on frequency of test blasting, geological structure of the site and blasting condition, so it is difficult to predict accurately using such an equation. Since PPV is response value from the ground, direct evaluation of the structure is impractical. Because of such a limit, engineers tend to use the commercial numerical analysis program in evaluating the stability of the structure more accurately. However, when simulate the explosion process using existing numerical analysis program, it's never easy to accurately simulate the complex conditions (fracture, crushing, cracks and plastic deformation) around blasting hole. For simulating such a process, the range for modelling will be limited due to the maximum node count and it requires extended calculation time as well. Thus, this study is intended to simulate the elastic energy after fractured zone only, instead of simulating the complex conditions of the rock that results from the blast, and the analysis of response characteristics of the velocity depending on shape and size of the fractured zone was conducted. As a result, difference in velocity and attenuation character were calculated depending on fractured zone around the blast source appeared. Propagation of vibration tended to spread spherically as it is distanced farther from the blast source.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.1
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• pp.80-90
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• 2001

The aim of this study is to develop the methodology which enables to identify the mechanical properties of element such as stress intensity factor by using the AE parameters. Considering the multivariate and nonlinear properties of AE parameters such as ringdown count, rise time, energy, event duration and peak amplitude from fatigue cracks of machine element the principal component regression(PCR) and artificial neural network(ANN) models for the estimation of stress intensity factor were developed and validated. The AE parameters were found to be very significant to estimate the stress intensity factor. Since the statistical values including correlation coefficients, standard mr of calibration, standard error of prediction and bias were stable, the PCR and ANN models for stress intensity factor were very robust. The performance of ANN model for unknown data of stress intensity factor was better than that of PCR model.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.5
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• pp.364-372
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• 2007

Purpose: This study was designed to investigate the cellular uptake of various tumor imaging radiopharmaceuticals in human breast cancer cells before and after paclitaxel exposure considering viable cell number. Materials and Methods: F-18-fluorodeoxyglucose, C-11-methionine, Tl-201, Tc-99m-MIBI, and Tc-99m-tetrofosmin were used to evaluate the cellular uptake in MCF-7 cells. MCF-7 cells were cultured in multi-well plates. Wells were divided into DMSO exposure control group, and paclitaxel exposure group. The exposure durations of paclitaxel with 10 nM or 100 nM were 2 h, 6 h, 12 h, 24 h, and 48 h. Results: Viable cell fraction was reduced as the concentration and exposure time of paclitaxel increased. After 10 nM paclitaxel exposure, the cellular uptake of all 5 radiopharmaceuticals was not reduced significantly, irrespective of exposure time and viable cell fraction. After 100 nM paclitaxel exposure, the cellular uptake of all 5 radiopharmaceuticals was enhanced significantly irrespective of viable cell fraction. The peak uptake was observed in experimental groups with paclitaxel exposure for 6 to 48 h according the type of radiopharmaceutical. When the cellular uptake was adjusted for the viable cell fraction and cell count, the peak cellular uptake was observed in experimental groups with paclitaxel exposure for 48 h, irrespective of the type of radiopharmaceutical. Conclusion: The cellular uptake of F-18-fluorodeoxyglucose, C-11-methionine, Tl-201, Tc-99m-MIBI, and Tc-99m-tetrofosmin did not reflect viable cell number in MCF-7 cells after paclitaxel exposure for up to 48 h.