• Journal of Korean Society of Water and Wastewater
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• v.34 no.4
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• pp.277-288
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• 2020

In this study, we performed algorithms to predict algae of Chlorophyll-a (Chl-a). Water quality and quantity data of the middle Nakdong River area were used. At first, the correlation analysis between Chl-a and water quality and quantity data was studied. We extracted ten factors of high importance for water quality and quantity data about the two weirs. Algorithms predicted how ten factors affected Chl-a occurrence. We performed algorithms about decision tree, random forest, elastic net, gradient boosting with Python. The root mean square error (RMSE) value was used to evaluate excellent algorithms. The gradient boosting showed 10.55 of RMSE value for the Gangjeonggoryeong (GG) site and 11.43 of RMSE value for the Dalsung (DS) site. The gradient boosting algorithm showed excellent results for GG and DS sites. Prediction value for the four algorithms was also evaluated through the Receiver operating characteristic (ROC) curve and Area under curve (AUC). As a result of the evaluation, the AUC value was 0.877 at GG site and the AUC value was 0.951 at DS site. So the algorithm's ability to interpret seemed to be excellent.

• Genomics & Informatics
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• v.16 no.4
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• pp.26.1-26.12
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• 2018

Shigella spp. constitutes some of the key pathogens responsible for the global burden of diarrhoeal disease. With over 164 million reported cases per annum, shigellosis accounts for 1.1 million deaths each year. Majority of these cases occur among the children of the developing nations and the emergence of multi-drug resistance Shigella strains in clinical isolates demands the development of better/new drugs against this pathogen. The genome of Shigella flexneri was extensively analyzed and found 4,362 proteins among which the functions of 674 proteins, termed as hypothetical proteins (HPs) had not been previously elucidated. Amino acid sequences of all these 674 HPs were studied and the functions of a total of 39 HPs have been assigned with high level of confidence. Here we have utilized a combination of the latest versions of databases to assign the precise function of HPs for which no experimental information is available. These HPs were found to belong to various classes of proteins such as enzymes, binding proteins, signal transducers, lipoprotein, transporters, virulence and other proteins. Evaluation of the performance of the various computational tools conducted using receiver operating characteristic curve analysis and a resoundingly high average accuracy of 93.6% were obtained. Our comprehensive analysis will help to gain greater understanding for the development of many novel potential therapeutic interventions to defeat Shigella infection.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.29-35
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• 2019

As the fourth industrial revolution is emerging, many companies are increasingly interested in smart factories and the importance of sensors is being emphasized. In the case that sensors for collecting sensing data fail, the plant could not be optimized and further it could not be operated properly, which may incur a financial loss. For this purpose, it is necessary to diagnose the status of sensors to prevent sensor' fault. In the paper, we propose a scheme to diagnose digital-sensor' fault by analyzing the rising time and falling time of digital sensors through the LSTM(Long Short Term Memory) of Deep Learning RNN algorithm. Experimental results of the proposed scheme are compared with those of rule-based fault diagnosis algorithm in terms of AUC(Area Under the Curve) of accuracy and ROC(Receiver Operating Characteristic) curve. Experimental results show that the proposed system has better and more stable performance than the rule-based fault diagnosis algorithm.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.146-155
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• 2020

This study was to evaluate the usefulness of gamma glutamyl transferase (GGT) as a surrogate marker predicting metabolic syndrome. 7,155 non obese men over the age of 20 were studied as subjects. The criteria for diagnosing MetS were the National Cholesterol Education Program - Third Adult Treatment Panel (NCEP-ATP III). The risk of developing MetS according to GGT was conducted logistic regression analysis, and the ROC (receiver operating characteristic) curve was obtained to confirm GGT ability to predict the risk of MetS. Regardless of age and body mass index, MetS had a 7.09 times higher risk of onset in the fourth quartile than in the first quartile of GGT (p<0.001). The AUC (area under the curve) of GGT for the diagnosis of MetS was 0.715, and the cutoff value of GGT was 40.0 U/L, the sensitivity was 65.0%, and the specificity was 70.2%. Therefore, GGT is considered to be a useful diagnostic index for diagnosing MetS.

• Journal of The Geomorphological Association of Korea
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• v.27 no.3
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• pp.87-103
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• 2020

The purpose of this study is to evaluate the risk of cropland and man-made infrastructures in a landslide-prone area using a GIS-based method. To achieve this goal, a landslide inventory map was prepared based on aerial photograph analysis as well as field observations. A total of 550 landslides have been counted in the entire study area. For model analysis and validation, extracted landslides were randomly selected and divided into two groups. The landslide causative factors such as slope, aspect, curvature, topographic wetness index, elevation, forest type, forest crown density, geology, land-use, soil drainage, and soil texture were used in the analysis. Moreover, to identify the correlation between landslides and causative factors, pixels were divided into several classes and frequency ratio was also extracted. A landslide susceptibility map was constructed using a bayesian predictive model (BPM) based on the entire events. In the cross validation process, the landslide susceptibility map as well as observation data were plotted with a receiver operating characteristic (ROC) curve then the area under the curve (AUC) was calculated and tried to extract a success rate curve. The results showed that, the BPM produced 85.8% accuracy. We believed that the model was acceptable for the landslide susceptibility analysis of the study area. In addition, for risk assessment, monetary value (local) and vulnerability scale were added for each social thematic data layers, which were then converted into US dollar considering landslide occurrence time. Moreover, the total number of the study area pixels and predictive landslide affected pixels were considered for making a probability table. Matching with the affected number, 5,000 landslide pixels were assumed to run for final calculation. Based on the result, cropland showed the estimated total risk as US $ 35.4 million and man-made infrastructure risk amounted to US $ 39.3 million.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.24-30
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• 2009

Purpose: Today, Prostate cancer has been gradually increasing, according to the change of internal incidence rate of cancer. Generally, prostate cancer has lead to dead over 90%, in case of metastasis of lymph node and bone. So, innovative development of new radiopharmaceutical and imaging modality is progressed for detection of that metastasis, in nuclear medicine, now. Therefore, this study shows the usefulness of $^{18}F$-Fluoride PET/CT improved diagnosability on bone metastasis of prostate cancer. Materials and Methods: In this study, 33 male patients with prostate cancer were examined (The mean age: $67.8{\pm}10.2$ years old). Every patient was done each whole body bone scan (WBBS) and $^{18}F$-Fluoride positron emission tomography/computed tomography ($^{18}F$-Fluoride PET/CT). And then, using Receiver Operating Characteristic Curve (ROC curve), each sensitivity and specificity of two modalities was measured and compared with. Results: In 22 patients (66.6%) of all, bone metastasis was detected. And, in WBBS, sensitivity was 63.6%, specificity, 81.8%; in $^{18}F$-Fluoride PET/CT, sensitivity was 100% and specificity was 90.9%. As a result of ROC curve, AUROC (The Area under an ROC) of WBBS was 0.778, and that of $^{18}F$-Fluoride PET/CT, 0.942. Conclusions: $^{18}F$-Fluoride PET/CT was higher both sensitivity and specificity than WBBS, and it was valuable to detect bone metastasis of prostate cancer more definitely, with 3D imaging realization. Also, in $^{18}F$-Fluoride PET/CT, physiological images were acquired in more short time than WBBS, so, it was possible to reduce patient's waiting time and complaint. Therefore, it is considered that $^{18}F$-Fluoride PET/CT is able to improve diagnosability by offering more accurate images, as cuts in a share of high cost.

• Journal of Preventive Medicine and Public Health
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• v.37 no.1
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• pp.51-58
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• 2004

Objectives : The purpose of this study was to estimate the prevalence of metabolic syndrome, as defined by the ATP III report, in some Korean adults and use the Asian-Pacific proposed waist circumference to investigate waist circumference in some Korean adults using ROC curves. Methods : Study subjects were seventy-five thousands and ninety one persons(47,979 men and 27,111 women) who were selected among the patients who visited hospital for health evaluation from January 2000 to December 2001. All subjects were measured by height, weight, waist and hip circumferences, blood pressure and blood chemistry(lipid profile). Results : The mean age was $41.6{\pm}8.5$ years in men, $41.1{\pm}10.4$ years in women(p<0.05). Body mass index was in the normal range in 35.3% of men, and 55.9% of women. In both men and women, blood pressure, blood sugar, total cholesterol and triglyceride were positively correlated with BMI. waist circumference, and Broca's index(p<0.01). However HDL. choloesterol was correlated negatively (p< 0.01). Using ROC curve, the calculated waist circumferences were 84 cm in men(sensitivity 61.4% and specificity 64.1%) and 74 cm in women(sensitivity 65.0% and specificity 73.2%). The age adjusted prevalences of the metabolic syndrome as defined by NCEP ATP III were different for men(6.4%) and women(14.6%). The prevalence increased from 1.2% among participants aged 20 through 29years to 15.0% among participants aged over 60years in men(p<0.05) and from 1.6% to 27.4% respectively, in women. The age adjusted prevalences, as defined by using the waist circumference that was recommended by WHO's regional office for the western Pacific, were 10.6% in men and 18.5% in women. The age adjusted prevalences, as defined by using the waist circumference that was calculated by the ROC curves, were 17.1% in men and 22.4% in women. And All prevalences were increased following increased BMI and Broca's index. Conculsions : The prevalence of metabolic syndrome in some Korean adults was lower than that in western adults. Nevertheless because waist circumference was differed among race and region, application of the same criteria was not proper. Morcover, a higher awareness was required in women, because the prevalence of metabolic syndrome was rapidly increased with increment of age.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.181-196
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• 2019

Floods can be caused by a variety of factors, and the main cause of floods is the exceeding of urban drainage system or river capacity. In addition, rainfall frequently occurs that causes large watershed runoff. Since the existing methodology of preparing for flood risk map is based on hydraulic and hydrological modeling, it is difficult to analyse for a large area because it takes a long time due to the extensive data collection and complex analysis process. In order to overcome this problem, this study proposes a methodology of mapping for flood vulnerable area that considered the surface runoff mechanism. This makes it possible to reduce the time and effort required to estimate flood vulnerabilities and enable detailed analysis of large areas. The target area is Seoul, and it was confirmed that flood damage is likely to occur near selected vulnerable areas by verifying using 2×2 confusion matrix and ROC curve. By selecting and prioritizing flood vulnerable areas through the surface runoff mechanism proposed in this study, the establishment of systematic disaster prevention measures and efficient budget allocation will be possible.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.227-234
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• 2017

This study evaluated the usefulness of the elasticity score and strain ratio in the differential diagnosis of benign and malignant nodules in thyroid elastography. We performed a retrospective analysis based on the results of fine needle aspiration cytology. The Chi-square test and the Mann-Whitney U test were used to analyze the difference between the five degrees of elasticity score and strain ratio according to the benign and malignant thyroid nodules. ROC curve analysis was used to determine the elasticity score and the best cut-off value of the strain ratio for the prediction of malignant nodules. There was a statistically significant difference (p=0.000) between the homogeneity of the elasticity score and the difference of the strain ratio between the benign and malignant nodule groups. On the ROC curve analysis, the elasticity score and the srain ratio for predicting benign and malignant nodules were determined as AUC 0.842, 0.700, cut-off value 3, 2.49 (p=0.001). Therefore, the elasticity score and strain ratio may be useful in the differential diagnosis of thyroid nodules.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.201-207
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• 2019

This study has evaluated whether the method of using the combination of different risk group, according to K-TIRADS classification and K-TIRADS classification in thyroid ultrasonography is useful in a differential diagnosis of benign and malignant nodules. The subject was patients underwent thyroid ultrasonography and retrospective analysis were performed based on the results of fine needle aspiration cytology. A chi-square test was performed for the difference analysis of the score system in K-TIRADS and different risk group according to the benign and malignant of thyroid nodule. The optimized cut off value was determined by the K-TIRADS score and different risk group to predict malignant nodule through ROC curve analysis. In the differential verification result of K-TIRADS and different risk group, according to the classification of benign and malignant nodule group each showed significant difference statistically(p=.001). In the point classification according to K-TIRADS for the prediction of benign and malignant in ROC curve analysis showed AUC 0.786, Cut-off value>2(p=.001), and in the different risk group, it was decided as AUC 0.640, Cut-off value>2(p=.001). When discovering the nodule in thyroid ultrasound, it is considered that the K-TIRADAS which helps in identifying benign and malignant thyroid nodules, it is considered to be helpful in the differential diagnosis of thyroid nodules, than the classification system according to Different risk group, and when applying the classification system according to K-TIRADS, it is considered that it can reduce unnecessary fine needle aspiration cytology and could be helpful in finding the malignant nodules early.