• The Korean Journal of Mycology
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• v.20 no.2
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• pp.109-117
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• 1992

Chemotactic responses of five motile saprophytic and one phytopathogenic bacteria e.g. Agrobacterium radiobacter, Bacillus subtilis, B. polymyxa, Pseudomonas aeruginosa, P. fluorescens and Xanthomonas malvacearum towards exudate of Cochliobolus sativus conidia, Fusarium of oxysporum f. sp. ciceri chlamydospores, Macrophomina phaseolina sclerotia and Phytophthora drechsleri f. sp. cajani oospores were determined in vitro at different abiotic conditions. In general, a positive correlation (r=0.76 to 0.89; P=0.05) was observed between concentration of fungal exudates and attraction of bacterial cells. Similarly, a significant (P=0.05; r=+0.82 to 0.95) positive correlation was noticed between chemotactic response and incubation period. The chemotactic response of bacteria was greatly influenced by temperature and pH of the test fungal exudate. The optimum temperature for maximum chemotaxis was $25^{\circ}C$ for A. radiobacter, $30^{\circ}C$ for B. polymyxa, P. aerugionosa, P. fluorescens and X. malvacearum and $35^{\circ}C$ for B. subtilis. Fungal exudates maintained at pH 7 attracted maximum number of bacteria. The response of bacterial cells to exudates at pH 3 and 11 was not significantly (P=0.05) different than that to the buffer (control). Chemotaxis of bacteria was observed towards attractants (fungal propagules and their exudates) when they were kept apart and bridged with the capillaries filled with non-attractant (buffer) or attractant (exudate).

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.291-299
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• 2004

Characterization of quantitative trait loci (QTL) was investigated in the experimental cross population between Berkshire and Yorkshire breed. A total of 512 F$_2$ offspring from 65 matting of F$_1$ parents were phenotyped the carcass traits included average daily gain (ADG), average backfat thickness (ABF), tenth rip backfat thickness (TRF), loin eye area (LEA), and last rip backfat thickness (LRF). All animals were genotyped for 125 markers across the genome. Marker linkage maps were derived and used in QTL analysis based on line cross least squares regression interval mapping. A decision tree to identify QTL with imprinting effects was developed based on tests against the Mendelian mode of QTL expression. To set the evidence of QTL presence, empirical significance thresholds were derived at chromosome-wise and genome-wise levels using specialized permutation strategies. Significance thresholds derived by the permutation test were validated in the data set based on simulation of a pedigree and data structure similar to the Berkshire-Yorkshire population. Genome scan revealed significant evidences for 13 imprinted QTLs affecting growth and body compositions of which nine were identified to be QTL with paternally expressed inheritance mode. Four of QTLs in the loin eye area (LEA), and tenth rip backfat thickness (TRF), a maternally expressed QTL were found on chromosome 10 and 12. These results support the useful statistical models to analyse the imprinting far the QTLs related carcass trait.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.188-193
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• 1998

Soil pH change is an important factor which determines soil chemical properties. It is an indicator of the effect of urban environmental pollution on soils and plant growth. The objective of this study was to assess the effect of air pollution on the soil of Seoul urban forests during the course of the air pollution being dipersed toward suburb area. Study sites were divided into four sections of concentric circles with 5km interval. Soil samples were collected from A and B horizons in the urban forests, and analyzed for soil pH, soil buffer capacity, cation exchange capacity, and base saturation. Soil pH ranged from 3.96 to 5.08 for A horizon and from 4.10 to 5.25 for B horizon, which were not significantly different among the sections. However, there was a trend of soil pH lowered at the sections close to the urban center. Soil buffer capacity was lower at 0-5km and 5-10km sections compared to that at the outer sections. Cation exchange capacity and base saturation were not different significantly among the sections. Following the pattern of air pollutants being dispersed from urban center to suburb, soil acidification was observed at the urban forests in Seoul area. Low level of soil buffer capacity toward the urban center was an indicator of soil acidification at the urban forests.

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.15-23
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• 1996

Preparing the era of forest resources management requires studies on forest fire. This study attempted to develop forest fire occurrence model using meteorological characteristics for the practical purposes of forecasting forest fire danger rate. To accomplish this goal, the relationships between forest fire occurrence and meteorological characteristics are estimated. In the process, the forest fire occurrence pattern of the study region(Taegu-Kyungpook) is categorized by employing qualification IV method. The study region was divided into three areas such as, Taegu, Andong and Pohang area. The meteorological variables emerged as affective to forest fire occurrence are relative humidity, longitude of sunshine, and duration of precipitation. To estimate the probability of forest fire danger, forest fire occurrence of three areas are regressed on the time series data of affective meteorological variables using logistic and probit model. The effectiveness of the models estimated are tested and showed acceptable degree of goodness. Those models developed would be helpful to increase the efficiency of forest fire management such as detection of forest fire occurrence and effective disposition of forest fire fight equipments.

• Restorative Dentistry and Endodontics
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• v.26 no.1
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• pp.86-94
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• 2001

기존의 광중합기는 높은 광강도를 제공함으로써 광중합 복합레진을 최대한 단축된 시간내의 중합을 목표로 하였다. 이러한 높은 광강도는 복합레진의 중합깊이, 중합률면에서는 우수하나 중합 반응속도가 빠름으로 인해 중합시 응력 발생이 높아진다는 일련의 보고가 있다. 최근에는 광중합 속도를 늦춤으로써 변연적합도 및 중합시 응력 발생을 낮추는 새로운 중합방법들이 제시되고 있다. 이에 본 실험에서는 광조사 강도의 변화가 광중합 복합레진의 중합반응 과정에 미치는 영향 및 중합된 복합레진의 중합률에 대한 영향을 분석하고자 하였다. 5개의 혼합형 광중합 복합레진 (Z-100, Spectrum, Z-250, Clearfil AP-X, P-60)을 사용하였으며 중합시 적용된 광조사 강도에 따라 6개의 실험군으로 정의하였다. 실험군과 이에 따른 광조사 방법은 다음과 같다. 1군은 110mW/$\textrm{cm}^2$로 40초 중합, 2군 210mW/$\textrm{cm}^2$로 40초 중합, 3군 410mW/$\textrm{cm}^2$로 40초 중합, 4군 620mW/$\textrm{cm}^2$로 40초 중합, 5군 110mW/$\textrm{cm}^2$로 10초 중합 후 1분 뒤 620mW/$\textrm{cm}^2$로 30초 중합, 6군 210mW/$\textrm{cm}^2$로 10초 중합 후 1분 뒤 410mW/$\textrm{cm}^2$로 30초 중합하였다. 광중합시 중합 반응 양상에 관한 분석은 시차주사 열계량기를 이용하여 37$^{\circ}C$ 항온상태에서 10분간의 열흐름곡선을 기록하였다. 기록된 열흐름곡선에서 중합 반응시 나타나는 중합열 및 최대 중합열에 이르는 시간을 기록하여 중합반응 속도를 측정하였다. 중합된 복합레진의 중합률은 Fourier Transform Infrared Spectrometer(FTIR)를 이용하였으며 2mm 두께의 복합레진 하방에서의 중합률을 측정하였다. 측정된 결과는 ANOVA 및 Student-Newman-Keuls 방법을 이용하여 유의성을 검증하였다. 실험결과 다음과 같은 결론을 얻었다. 1. 광중합 복합레진 중합시 광조사 강도가 증가할수록 중합열은 증가하였으나 통계적 유의성은 보이지 않았다 (p>0.05). 2. 최대 중합열에 이르는 시간은 광조사 강도가 증가할수록 단축되었다. 이단계 중합방법을 사용한 경우 중합반응 속도를 감소시킬 수 있음을 보였다. 3. 광조사 강도가 증가할수록 중합률은 증가하였다. 이단계 중합방법을 사용한 경우 연속적인 고광강도를 사용한 경우와 유사한 높은 중합률을 보였다. 4. 중합률면에서 광중합복합레진의 중합시 400mW/$\textrm{cm}^2$ 이상의 광강도가 필요한 것으로 나타났다.

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.189-196
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• 2003

Purpose : Ureteral duplication is a common urologic anomaly and early diagnosis may prevent irreversible renal damage. We thus aimed to evaluate the benefits of prenatal sonography in early detection. Methods : We retrospectively studied 55 children with duplicated systems who were admitted to Severance Hospital, Yonsei University, Seoul, Korea from January 1998 to July 2003. Results : The mean age at diagnosis was 2.3 years old. 89% of the children had complete duplicated ureter. 47% of the children visited the hospital with an initial complaint of abnormal prenatal sonographic findings. Among these patients, 70.8% had DMSA defects. The mean differential renal function(DRF) in the DMSA scan was 48.2% in the group diagnosed prenatally. In the postnatally-diagnosed group, DMSA defects were found in 67.7% patients and the mean DRF was 45.5%. Conclusion : In comparison with the past studies, the mean age at diagnosis is becoming younger, and the proportion of abnormal prenatal sonography as an initial complaint larger. Other clinical manifestations were similar. The difference of the renal damage between the prenatally diagnosed group and the postnatally diagnosed group was not statistically significant. A multi-center study may help to prove the importance of prenatal sonography in early diagnosis and treatment of ureteral duplication. (J Korean Soc Pediatr Nephrol 2003;7:189-196)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.349-356
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• 2021

Since the 1960s, traffic infrastructure, such as bridges, has increased rapidly in Korea as urbanization and industrialization progressed due to economic growth. As the scale of the bridge becomes larger, stability analysis of the superstructure of the bridge is being conducted actively, but scour stability analysis for the substructure of the bridge has not been conducted sufficiently. This study is a basic investigation to prevent large-scale disasters caused by scouring in bridge piers. A simple linear regression model was used to analyze the scour depth calculated through seventeen scour depth calculation formulae, and the scour depth measured through hydraulic model experiments. As a result, the Coleman (1971) formula was the best method among the scour depth calculation formulae, and the Froehlich (1987) formula was the most effective method for calculating the scour depth. In addition, a review using a simple regression model confirmed that the scour depth calculation formulae of CSU (1993), Coleman (1971), and Froehlich (1987) can predict a similar scour depth by reflecting domestic stream characteristics. This study can calculate the scour depth reflecting the environmental conditions of Korea in future stream design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.477-483
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• 2021

In a military maintenance system, the standard maintenance man-hour of weapon systems is a tool to estimate the maintenance capabilities of maintenance units, provide standards for determining the maintenance needs and workload, and provide basic data for establishing a maintenance plan. The standard maintenance man-hours of major weapon systems have already been derived and used, but the standard maintenance man-hour in a wartime maintenance environment has not been computed. Therefore, the standard wartime maintenance man-hours need to be derived and This study proposes a process and method of computing the maintenance man-hours. In addition, this work suggests the criteria of collecting and screening data that is necessary for estimating the standard maintenance man-hours and introduces a methodology for analyzing the characteristics of maintenance man-hour distribution in the process. The proposed process first designs a model that reflects the wartime maintenance environment, selects statistical techniques, collects maintenance data, analyzes the descriptive statistics, estimates the distribution, and finally presents representative values of maintenance man-hour. Based on the proposed method, the standard wartime maintenance man-hours of the four weapon systems were calculated, and the distribution of the maintenance man-hours was analyzed to follow a lognormal distribution, and the method presented reliable results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.279-289
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• 2006

The reconstruction of low dimension nonlinear behavior from the hydrologic time series has been an active area of research in the last decade. In this study, we present the applications of a powerful state space reconstruction methodology using the method of Support Vector Machines (SVM) to the Great Salt Lake (GSL) volume. SVMs are machine learning systems that use a hypothesis space of linear functions in a Kernel induced higher dimensional feature space. SVMs are optimized by minimizing a bound on a generalized error (risk) measure, rather than just the mean square error over a training set. The utility of this SVM regression approach is demonstrated through applications to the short term forecasts of the biweekly GSL volume. The SVM based reconstruction is used to develop time series forecasts for multiple lead times ranging from the period of two weeks to several months. The reliability of the algorithm in learning and forecasting the dynamics is tested using split sample sensitivity analyses, with a particular interest in forecasting extreme states. Unlike previously reported methodologies, SVMs are able to extract the dynamics using only a few past observed data points (Support Vectors, SV) out of the training examples. Considering statistical measures, the prediction model based on SVM demonstrated encouraging and promising results in a short-term prediction. Thus, the SVM method presented in this study suggests a competitive methodology for the forecast of hydrologic time series.

• Journal of Korea Water Resources Association
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• v.56 no.8
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• pp.471-484
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• 2023

Deep learning models based on generative adversarial neural networks are specialized in generating new information based on learned information. The deep generative models (DGMR) model developed by Google DeepMind is an generative adversarial neural network model that generates predictive radar images by learning complex patterns and relationships in large-scale radar image data. In this study, the DGMR model was trained using radar rainfall observation data from the Ministry of Environment, and rainfall prediction was performed using an generative adversarial neural network for a heavy rainfall case in August 2021, and the accuracy was compared with existing prediction techniques. The DGMR generally resembled the observed rainfall in terms of rainfall distribution in the first 60 minutes, but tended to predict a continuous development of rainfall in cases where strong rainfall occurred over the entire area. Statistical evaluation also showed that the DGMR method is an effective rainfall prediction method compared to other methods, with a critical success index of 0.57 to 0.79 and a mean absolute error of 0.57 to 1.36 mm in 1 hour advance prediction. However, the lack of diversity in the generated results sometimes reduces the prediction accuracy, so it is necessary to improve the diversity and to supplement it with rainfall data predicted by a physics-based numerical forecast model to improve the accuracy of the forecast for more than 2 hours in advance.