• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.1949-1953
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• 2014

Background: CA125 and HE4 are used in calculating Risk of Malignancy Algorithm (ROMA); and Risk of Malignancy Index (RMI). However, studies showed that normal levels of CA125, and HE4 differ among ethnicities such as between Asians and Caucasians, thus affecting the accuracy of the RMI score and ROMA in predicting ovarian malignancy. This study aimed to determine whether new or modified cutoff values for Ca125, HE4, the RMI score, and ROMA resulted in a better prediction of malignancy compared with the previous or standard ones. Materials and Methods: Serum level of CA125 and HE4 from 128 patients with diagnosis of ovarian tumor that had been collected before surgery at Cipto Mangunkusumo General Hospital (CMH) in Jakarta from November 2010 until May 2011 were reviewed and analysed. The standard cutoff values of these biomarkers, RMI, and ROMA were modified by using logistic regression model. The modified cutoff values were compared to the standard cutoff values in terms of sensitivity, specificity, and accuracy. Results: The modified cutoff value of CA125, HE4, RMI score and ROMA were 165.2 U/mL, 103.4 pM, 368.7, 28/54. The sensitivity and specificity of the modified cutoff values CA125, HE 4, RMI score and ROMA in differentiating benign from malignant and borderline were 67% and 75,4%; 73.1% and 85.2%; 73.1% and 80.3%; and 77.6% and 86.9%. While the sensitivity and specificity of the standard cutoff value of CA125; HE4; RMI score; and ROMA were 91% and 24.6%; 83.6% and 65%; 80.6% and 65.6%; and 91.0% and 42.6%. The accuracy of modified cutoff values compared with standard cutoff values were: 71.2% vs 59.3%, 78.9% vs 75% vs, 76.5% vs 73.4%, and 82% vs 67.9%. Conclusions: The new or modified cutoff values of Ca125, HE4, RMI score and ROMA resulted in higher accuracy compared to the previous or standard ones, at the cost of reduced sensitivity.

• Communications for Statistical Applications and Methods
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• 제3권2호
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• pp.13-19
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• 1996

Cook's distance(Cook, 1997) is one of the most widely used influence measures to assess the influence of single observations or sets of observations in the linear regression model. After computing Cook(1977) suggested guidelines based on a confidence ellipsoid for the regression parameter ${\beta}$. In this paper, we suggest cutoff values for Cook's distance cia Monte Carlo simulation, and compare them with Cook's guidelines. An example based on a real data set is given.

• Korean Journal of Radiology
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• 제23권12호
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• pp.1260-1268
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• 2022

Objective: To propose standardized MRI-proton density fat fraction (PDFF) cutoff values for diagnosing hepatic steatosis, evaluated using contemporary PDFF measuring methods in a large population of healthy adults, using histologic fat fraction (HFF) as the reference standard. Materials and Methods: A retrospective search of electronic medical records between 2015 and 2018 identified 1063 adult donor candidates for liver transplantation who had undergone liver MRI and liver biopsy within a 7-day interval. Patients with a history of liver disease or significant alcohol consumption were excluded. Chemical shift imaging-based MRI (CS-MRI) PDFF and high-speed T2-corrected multi-echo MR spectroscopy (HISTO-MRS) PDFF data were obtained. By temporal splitting, the total population was divided into development and validation sets. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of the MRI-PDFF method. Two cutoff values with sensitivity > 90% and specificity > 90% were selected to rule-out and rule-in, respectively, hepatic steatosis with reference to HFF ≥ 5% in the development set. The diagnostic performance was assessed using the validation set. Results: Of 921 final participants (624 male; mean age ± standard deviation, 31.5 ± 9.0 years), the development and validation sets comprised 497 and 424 patients, respectively. In the development set, the areas under the ROC curve for diagnosing hepatic steatosis were 0.920 for CS-MRI-PDFF and 0.915 for HISTO-MRS-PDFF. For ruling-out hepatic steatosis, the CS-MRI-PDFF cutoff was 2.3% (sensitivity, 92.4%; specificity, 63.0%) and the HISTO-MRI-PDFF cutoff was 2.6% (sensitivity, 88.8%; specificity, 70.1%). For ruling-in hepatic steatosis, the CS-MRI-PDFF cutoff was 3.5% (sensitivity, 73.5%; specificity, 88.6%) and the HISTO-MRI-PDFF cutoff was 4.0% (sensitivity, 74.7%; specificity, 90.6%). Conclusion: In a large population of healthy adults, our study suggests diagnostic thresholds for ruling-out and ruling-in hepatic steatosis defined as HFF ≥ 5% by contemporary PDFF measurement methods.

• 대한핵의학회지
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• 제28권3호
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• pp.391-396
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• 1994

건강 검진시 정상으로 판정된 한국 성인 2626명의 혈청 암태아성항원 농도를 이용하여 통계적 분석을 실시하였다. 1) 한국 정상 성인에서 혈청 암태아성항원의 경계치는 남자에서 9.28ng/m1, 여자에서 5.90ng/m1이었으며 이를 연령군별로 흡연력에 따른 분포를 보았더니 50세이상에선 남여 모두 항상 흡연자가 비흡연자보다 높았다. 각 연령별 흡연력에 따른 경계치는 Table 4와 같았다. 2) 혈청 암태아성항원은 연령이 증가함에 따라 증가하였다. 3) 혈청 암태아성항원은 흡연군에서 현재 비흡연군과 과거 흡연군 보다 높았다. 4) 혈청 암태아성항원은 남성에서 여성에서 보다 높았다. 5) 흉부 방사선 촬영에서 결핵 소견이 있으면 정상인 군보다 혈청 암태아성항원이 높았다. 6) 혈청 암태아성하원은 음주력과 비만도와는 연관이 없었다.

• 한국지반공학회논문집
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• 제35권8호
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• pp.5-15
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• 2019

이 연구는 오염원 유출을 방지하기 위한 해상폐기물매립장 차수시스템에 요구되는 적절한 기준을 제안하기 위해 수행되었다. 차수시스템은 바닥층과 연직벽으로 구성된다. 바닥층은 불투수 점토층으로 연직벽은 이중벽체로 외곽벽체는 강관쉬트파일로 외력에 대한 저항을 담당하고 연직내부벽체가 차수를 담당하는 것으로 가정하였다. SEEP/W와 CTRAN/W 프로그램을 이용하여 침투-이류-분산 해석을 정상류 및 비정상류 조건에서 실시하였다. 해석결과, 정상류 조건에서 비정상류 조건 보다 오염원 이동이 크게 나타나 설계관점에서 차수기준은 정상류조건에서 산정된 값을 적용하는 것이 타당한 것으로 나타났다. 바닥층의 점토지반이 균질하고 연직차수시스템의 시공에 문제가 없다는 전제하에 정상류조건에서 오염원 이동의 차수에 요구되는 점토층 및 연직차수벽의 투수계수, 두께, 근입깊이 등이 제안되었다.

• 대한지리학회지
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• 제39권6호
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• pp.845-862
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• 2004

본 연구는 경기, 강원 지역을 대상으로 감입곡류절단 지형의 공간적 분포 특성을 검토하였다. 강원도에서도 높은 산지지역인 정선군 및 인제군을 주로 흐르는 내린천 및 동대천 등의 하천에서 곡류절단면의 분포 밀도가 가장 높았다. 곡류절단의 발생은 제4기 동안 반복적으로 나타났으며. 빙기와 간빙기 사이의 기후 변동기에 집중된 것으로 추정된다. 지질별로는 퇴적암에서 분포 빈도가 가장 높고, 화성암에서 가장 낮았다. 지질구조로 볼 때, 태백산맥으로부터 서쪽 $11{\sim}20km$ 거리에 가장 많이 분포하며. 적종하천이나 적종하천에 유입하는 지류의 하구부, 즉 단층선에 직교하는 하천에서 곡류절단이 가장 활발하였다. 태백산맥에서의 거리와 해발고도와의 관계는 영서하천에서 매우 뚜렷하고, 하상비고 및 절단면 면적과의 관계에서는 태백산맥에서 서쪽 12km를 기준으로 동서로 갈수록 값이 작아진다. 기반암 종류에 대한 해발고도. 하상비고, 하천차수와의 관계는 공통적으로 퇴적암 지역에서 값이 가장 높으며, 화산암 지역에서 가장 낮다.

• Journal of Korean Dental Science
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• 제16권1호
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• pp.47-62
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• 2023

Purpose: We aimed to investigate the objective cutoff values of unstimulated flow rates (UFR) and stimulated salivary flow rates (SFR) in patients with xerostomia and to present an optimal machine learning model with a classification and regression tree (CART) for all ages. Materials and Methods: A total of 829 patients with oral diseases were enrolled (591 females; mean age, 59.29±16.40 years; 8~95 years old), 199 patients with xerostomia and 630 patients without xerostomia. Salivary and clinical characteristics were collected and analyzed. Result: Patients with xerostomia had significantly lower levels of UFR (0.29±0.22 vs. 0.41±0.24 ml/min) and SFR (1.12±0.55 vs. 1.39±0.94 ml/min) (P<0.001), respectively, compared to those with non-xerostomia. The presence of xerostomia had a significantly negative correlation with UFR (r=-0.603, P=0.002) and SFR (r=-0.301, P=0.017). In the diagnosis of xerostomia based on the CART algorithm, the presence of stomatitis, candidiasis, halitosis, psychiatric disorder, and hyperlipidemia were significant predictors for xerostomia, and the cutoff ranges for xerostomia for UFR and SFR were 0.03~0.18 ml/min and 0.85~1.6 ml/min, respectively. Conclusion: Xerostomia was correlated with decreases in UFR and SFR, and their cutoff values varied depending on the patient's underlying oral and systemic conditions.

• 품질경영학회지
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• 제22권1호
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• pp.142-151
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• 1994

Optimum screening procedures using prior information are presented. An optimal cutoff value on the screening variable X minimizing the expected total cost is obtained for the normal model; it is assumed that a continuous screening variable X given a dichotomous performance variable T is normally distributed and that costs are incurred by screening inspection and misclassification errors. Methods for finding optimal cutoff values based on the prior distributions for unknown parameters are presented.

• 한국수산과학회지
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• 제39권4호
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• pp.313-317
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• 2006

To prepare oligouronic acids from high-molecular-weight alginates, sea tangle (Laminaria japonica) alginates were hydrolyzed at various pHs for 1 hr at 80$^{\circ}C$. The effects of hydrolysis pH (HpH) on the average molecular weight (AMW) and MW distribution ratios (DRs) in the hydrolyzed alginates were investigated. As HpH decreased, the DRs of the alginates with MW>500 kDa and MW=300-500 kDa decreased exponentially, while it increased exponentially for MW<50 kDa. For MW=100-300 kDa, DR increased exponentially as HpH fell from 5.0 to 3.5, and then decreased exponentially. Similarly, for MW=50-100 kDa, DR increased exponentially as HpH increased to 1.0 from 5.0, and then decreased exponentially. As HpH decreased, the MW cutoff size and AMW of alginates fraction with the highest DR were decreased. For HpH 4.5 and 5.0, the MW cutoff size with the highest DRs was MW=300-500 kDa; the DRs were 28.9 and 32.6%, respectively; and the AMW of both was about 400 kDa, for HpH 3.5 and 4.0, the cutoff size was MW=100-300 kDa; the DRs were about 28%: and the AMWs were both about 200 kDa. For HpH 3.0, the cutoff size was MW=50-100; the DR was 29.0%; and the AMW was 73 kDa. For HpH values below 2.0, the MW cutoff size with the highest DRs was MW<50 kDa, and all of the AMWs were below 28 kDa.

• 대한의생명과학회지
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• 제23권2호
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• pp.118-127
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• 2017

Elevated serum uric acid and resting heart rate are risk factors and predictors of metabolic syndrome. However, few studies have examined the optimal cutoff value for serum uric acid and resting heart rate to predict metabolic syndrome in Korean adults. Subjects for this study were 22,302 adults (average age 45 years old), who underwent health screening examination from January 2010 to December 2012 at the Health Promotion Center of one hospital in Gyeonggi-do for general health check-up. The uric acid and resting heart rate cutoff values were calculated by ROC analysis for metabolic syndrome. Elevated serum uric acid and resting heart rate were associated with an increased prevalence of metabolic syndrome in Korean adults. The optimal cutoff value for uric acid level to predict metabolic syndrome in adults was 4.95 mg/dL (male 6.35, female 4.55) and optimal cutoff value for resting heart rate to predict metabolic syndrome was 68 beats per minute (male 66, female 68). However, serum uric acid and resting heart rate were found to have limitations for the diagnosis of metabolic syndrome.