• 한국보건간호학회지
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• 제32권2호
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• pp.304-318
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• 2018

Purpose: This study examined the characteristic of the Injury Severity Score (ISS) of Korean geriatric patients with a traumatic injury in a nationally representative sample to determine the optimal cutoff of ISS of mortality according to age. Methods: The subjects were 3,018 non-elderly patients and 1,584 elderly patients with an ISS and Korean Triage and Acuity Scale (KTAS) in 2016 from the data of the Health Insurance Review and Assessment Service. The traumatic characteristics of the elderly and non-elderly were compared by stratifying the ISS. Receiver Operating Characteristic (ROC) curve analysis was used to find the optimal cutoff of ISS of mortality according to age. Results: The elderly were more prone to severe trauma than the non-elderly were. The distribution of KTAS grades was lower, even though the severity of ISS was as high as that of the non-elderly. The optimal cutoff score of the ISS for mortality in the ROC curve was lower in elderly over 65 years than in the other age group. Conclusion: The elderly are more prone to severe trauma and death than non-elderly, even though their ISS is low. Therefore, a strategy to prevent elderly from experiencing serious trauma and managing their geriatric trauma actively is needed.

• Ecology and Resilient Infrastructure
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• 제7권4호
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• pp.327-335
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• 2020

본 연구에서는 홍수해석 등 수치모형을 이용한 기존의 홍수위험지역 선정 시 필요한 시간과 노력을 절감하고자 유출메커니즘 기반의 지형 분석을 통해 홍수취약지역을 제시하고자 한다. 유출메커니즘 기반의 홍수취약지역은 강우-유출수의 지표면 흐름누적 특성에 유리한 지역으로 일반적으로 저지대, 완경사, 하천 등이 해당된다. 분석을 위해 대상지역인 서울시의 수치지형도를 이용하여 표고, 경사도, 수직 및 수평 사면 곡률, 지표습윤계수 (Topographic Wetness Index, TWI), 유수력 지수 (Stream Power Index, SPI), 하천 및 맨홀과의 거리 등 8개의 지형학적 인자를 고려하였다. 지형학적 인자들과 실제 침수흔적자료와의 ROC (Receiver Operation Characteristic) 분석 결과, 표고, 경사도, 지표습윤계수, 맨홀과의 거리 등 4개의 지형학적 인자가 침수지역을 잘 설명하는 것으로 나타났다. 홍수취약지역 선정 시 본 연구에서 제안하는 다양한 인자에 대한 우선순위 산정 방안은 홍수에 기여하는 지형학적 분석 요소를 간소화 시킬 수 있을 것으로 판단된다.

• 치과방사선
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• 제29권1호
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• pp.261-274
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• 1999

Objectives: The purpose of this study was to evaluate the optimal distance and angle of observers by modulation transfer functions(MTFs) and receiver operating characteristics(ROCs), Material and Methods: Digital periapical radiograms were taken from 43 patients who have dental diseases(19 patients : dental caries. 12 patients : periapical lesions, 12 patients : periodontal diseases). Segmental images(4×4cm) were evaluated by 4 MTFs and ROC analysis. Results: The optimal distance(magnification) using MTF by Mannos & Sakrison was 12.97. and those by Nill. Ngan and Rao were 8.39, 4.78. 5.84 respectively. The optimal distance obtained from 4 radiologists by ROC analysis was 32cm(Az value: 0.89). and it was 40cm(Az value: 0.78) from 4 non-radiologists. There were significant differences of Az values between 4 radiologists and 4 non-radiologists at 24. 32 and 40cm (P<0.05). No significant differences of optimal distances were observed using 4 MTFs among +20, +10, 0, -10, -20 degrees(P>0.05). The optimal angle obtained from 4 radiologists by ROC analysis was +20 degree(Az value: 0.91). and no significant differences of Az values were observed among +20, +10, 0, -10 and -20 degrees(P>0.05). The optimal angle obtained from 4 non-radiologists by ROC analysis was 0 degree(Az value : 0.81). and no significant differences of Az values were observed among +20, +10, 0, -10 and -20 degrees(P>0.05). And there was significant difference of Az value between 4 radiologists and 4 non-radiologists at +20 degree(P<0.05). but no significant differences of Az values were observed among +10, 0, -10 and -20 degrees(P>0.05).

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.156-156
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• 2020

가뭄은 다른 자연재해에 비해 진행 속도가 느리고 발생 시작 시기가 명확하지 않다. 또한 피해지역이 광범위하다는 점에서 사회, 경제적 피해와 농업 생산 시스템 및 수확량 등 농업 전반에 걸쳐 직접적인 영향을 미치고 있다. 전지구적 기후변화로 인해 국내의 가뭄 발생빈도는 2000년 이후 증가하고 있으며, 가뭄의 정량적 분석은 선제적 가뭄 대응을 위해 필요하다. 현재 국내에서는 여러 유관기관에서 지상 관측 데이터를 활용하여 가뭄을 모니터링하고, 가뭄 공간 분포 지도를 제공하고 있다. 하지만 지상 관측 데이터를 통한 가뭄 분포 지도는 미계측 지역에 대한 데이터 취득이 어렵고, 지형학적 특성을 고려하지 못하는 한계점이 있다. 이러한 한계점을 보완하기 위해 수자원 및 재해 분야에서 위성영상이 활용되고 있다. 위성영상을 활용한 가뭄 판단 및 예측에는 정규식생지수 (Normalized Difference Vegetation Index, NDVI)가 사용되고 있으며, 식생지수는 가뭄 발생, 진행 등에 있어 즉각적인 반응이 어렵다는 단점이 있다. 본 연구에서는 잠재 증발산과 실제 증발산의 비를 이용해 산정된 위성영상 기반 가뭄 지수인 Evaporative Stress Index (ESI)를 활용하였다. NASA (National Aeronautics and Space Administration)에서 제공하는 ESI는 전지구를 대상으로 5km 해상도로 제공하고 있다. 하지만 국내 가뭄 판단을 위해서는 높은 해상도의 영상이 필요하며, 본 연구에서는 MODIS (Moderate Resolution Imaging Spectroradiometer) 영상을 활용한 ESI의 산정을 통해 해상도의 문제를 개선하고자 한다. 산정한 500m 해상도의 ESI는 기존 5km 해상도의 ESI와 비교 검증하였으며, SPI 및 과거 가뭄 발생 현황 자료를 근거로 ROC (Receiver Operating Characteristics) 분석을 통해 시군 단위 농업가뭄평가의 적용성을 확인하고 한다.

• 대한간호학회지
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• 제41권6호
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• pp.758-767
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• 2011

Purpose: This study was done to examine the threshold value of estimated height loss at which the risk of osteoporosis increases and to verify its discriminative ability in the detection of osteoporosis. Methods: It was conducted based on epidemiological descriptive methods on 732 Korean women at a public healthcare center in Seoul between July and November 2010. ANOVA, Pearson correlation, logistic regression analysis and receiver operating characteristics (ROC) curve were used for data analysis. Results: There was an age-related correlation between bone mineral density (lumbar spine: F=37.88, p<.001; femur: F=54.27, p<.001) and estimated height loss (F=27.68, p<.001). Estimated height loss increased significantly with decreasing bone mineral density (lumbar spine: r=-.23, p<.001; femur: r=-.34, p<.001). The odds ratio for the point at which the estimated height loss affects the occurrence of osteoporosis was found to increase at a cut-off value of 2 cm and the area under ROC curve was .71 and .82 in lumbar spine and femur, respectively. Conclusion: The optimal cut-off value of the estimated height loss for detection of osteoporosis was 2 cm. Height loss is therefore a useful indicator for the self-assessment and prognosis of osteoporosis.

• 재활간호학회지
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• 제17권1호
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• pp.10-17
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• 2014

Purpose: The Leeds Sleep Evaluation Questionnaire (LSEQ) translated into Korean was modified to easily apply and reduce respondents' confusion and was evaluated for psychometric properties and discriminant ability. Methods: A total of 960 Korean adults aged 45 years and older participated in this cross-sectional survey. To test reliability, validity and discriminant ability, Cronbach's alpha, correlation analysis, confirmatory factor analysis, simple regression analysis and receiver operating characteristics (ROC) curve analysis were used. Results: Item-total correlations ranged between 62~.85 and Cronbach's alpha was .95. Area under ROC was .86 (95% CI: .83~.90) and the optimal cutoff score was identified as ${\leq}$ 66 (sensitivity, .77; specificity, .84; positive/negative predictive values, .49/.95). Using this cutoff score, the prevalence of insomnia in the study sample was 25.8% and tended to be more common in female and older groups. Conclusion: The data supported the psychometric properties of Korean Modified Leeds Sleep Evaluation Questionnaire (KMLSEQ) as an acceptable sleep measurement. In addition, KMLSEQ is likely to be a useful screening tool for insomnia.

• 임상간호연구
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• 제26권2호
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• pp.254-264
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• 2020

Purpose: This study was to examine the reliability and validity of the Korean version of the Cornell Assessment of Pediatric Delirium (CAPD). Methods: For testing the reliability of the Korean version of the CAPD, this study calculated the internal consistency (Cronbach's α) and the Interrater Correlation Coefficient (ICC) by comparing the independent assessment results of three nurses in Pediatric Intensive Care Unit (PICU). For testing the validity of the Korean version of the CAPD, the assessment result of the Korean version of the CAPD compared with that of the Diagnostic and Statistical Manual of Mental Disorders V (DSM-V). Receiver Operating Characteristics (ROC) analysis was used for measuring sensitivity and specificity. Results: Overall interrater reliability of the Korean version of the CAPD, ICC was .98 (95% CI .96~.99). Cronbach's α was .91 for eight items. The concordance between the Korean version of the CAPD and psychiatrist's diagnosis was 90.0%. When the Korean version of the CAPD has the cut point of 9, sensitivity was 93.8%, and specificity was 75.0%. The area under the curve indicated by the ROC analysis was .88. Conclusion: The Korean version of the CAPD showed good reliability and validity. This tool will be useful for pediatric delirium screening and management in Korean PICU.

• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.69-78
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• 2023

With the global rise of digital data, the uncontrolled quantity of data is susceptible to cyber warfare or cyber attacks. Therefore, it is necessary to improve cyber security systems. This research studies the behavior of malicious acts and uses Higuchi Fractal Dimension (HFD), which is a non-linear mathematical method to examine the intricacy of the behavior of these malicious acts and anomalies within the cyber physical system. The HFD algorithm was tested successfully using synthetic time series network data and validated on real-time network data, producing accurate results. It was found that the highest fractal dimension value was computed from the DoS attack time series data. Furthermore, the difference in the HFD values between the DoS attack data and the normal traffic data was the highest. The malicious network data and the non-malicious network data were successfully classified using the Receiver Operating Characteristics (ROC) method in conjunction with a scaling stationary index that helps to boost the ROC technique in classifying normal and malicious traffic. Hence, the suggested methodology may be utilized to rapidly detect the existence of abnormalities in traffic with the aim of further using other methods of cyber-attack detection.

• 말소리와 음성과학
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• 제4권3호
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• pp.103-110
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• 2012

In this paper, a target signal detection method using multiple signal classification (MUSIC) algorithm is proposed. The MUSIC algorithm is a subspace-based direction of arrival (DOA) estimation method. Using the inverse of the eigenvalue-weighted eigen spectra, the algorithm detects the DOAs of multiple sources. To apply the algorithm in target signal detection for GSC-based beamforming, we utilize its spectral response for the DOA of the target source in noisy conditions. The performance of the proposed target signal detection method is compared with those of the normalized cross-correlation (NCC), the fixed beamforming, and the power ratio method. Experimental results show that the proposed algorithm significantly outperforms the conventional ones in receiver operating characteristics (ROC) curves.

• Communications for Statistical Applications and Methods
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• 제30권1호
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• pp.21-35
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• 2023

Metabolic syndrome is a serious disease that can eventually lead to various complications, such as stroke and cardiovascular disease. In this study, we aimed to identify the risk factors related to metabolic syndrome for its prevention and recognition and propose a nomogram that visualizes and predicts the probability of the incidence of metabolic syndrome. We conducted an analysis using data from the Korea National Health and Nutrition Survey (KNHANES VII) and identified 10 risk factors affecting metabolic syndrome by using the Rao-Scott chi-squared test, considering the characteristics of the complex sample. A naïve Bayesian classifier was used to build a nomogram for metabolic syndrome. We then predicted the incidence of metabolic syndrome using the nomogram. Finally, we verified the nomogram using a receiver operating characteristic curve and a calibration plot.