• 대한원격탐사학회지
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• 제33권4호
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• pp.359-375
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• 2017

We developed fog detection algorithm (KNU_FDA) based on the optical and textural properties of fog using satellite (COMS) and ground observation data. The optical properties are dual channel difference (DCD: BT3.7 - BT11) and albedo, and the textural properties are normalized local standard deviation of IR1 and visible channels. Temperature difference between air temperature and BT11 is applied to discriminate the fog from other clouds. Fog detection is performed according to the solar zenith angle of pixel because of the different availability of satellite data: day, night and dawn/dusk. Post-processing is also performed to increase the probability of detection (POD), in particular, at the edge of main fog area. The fog probability is calculated by the weighted sum of threshold tests. The initial threshold and weighting values are optimized using sensitivity tests for the varying threshold values using receiver operating characteristic analysis. The validation results with ground visibility data for the validation cases showed that the performance of KNU_FDA show relatively consistent detection skills but it clearly depends on the fog types and time of day. The average POD and FAR (False Alarm Ratio) for the training and validation cases are ranged from 0.76 to 0.90 and from 0.41 to 0.63, respectively. In general, the performance is relatively good for the fog without high cloud and strong fog but that is significantly decreased for the weak fog. In order to improve the detection skills and stability, optimization of threshold and weighting values are needed through the various training cases.

• 대한예방한의학회지
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• 제20권2호
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• pp.17-26
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• 2016

Objectives : We presented the results of reliability study in advance, and analyzed agreement between Korean medicine doctors(KMDs)' diagnosis and cold-heat pattern identification questionnaire(CHPI)'s diagnosis. Methods : This survey was conducted from May 16 to 17, 2015. The subjects were 93 adults living in rural society. Diagnosis of CHPI was performed by 2 KMDs who have clinical experience more than 5 years. The KMDs' diagnosis was set as a reference index, and then we compare 23 items(cold pattern 11 items and heat pattern 12 items) of CHPI questionnaire and 15 items(cold pattern 8 items and heat pattern 7 items) that were brief form of it. We had cut-off value by standard of KMDs' diagnosis using receiver operating characteristic-curve(ROC-curve), with which we calculated agreement including kappa value. Correlation analysis between CHPI evaluation score by KMDs and by the questionnaire was fulfilled as well. Results : Agreement about 11 and 8 cold pattern items showed 87.1% together, and the value of kappa each recorded 0.742 and 0.741. Agreement about 12 and 7 heat pattern items suggested 81.7% and 78.5%, and the value of kappa showed 0.634 and 0.570. Correlation coefficients were 0.803 of 11 items and 0.761 of 8 items about cold pattern. In addition, correlation coefficients were 0.789 of 12 items and 0.767 of 7 items about heat pattern. The significant probability (p-value) was under 0.001. Conclusions : We have developed CHPI questionnaire involving reliability and agreement based on usual symptoms, and hope additional complements so that Korean medicine diagnostics and Korean preventive medicine would be improved.

• Clinical and Experimental Reproductive Medicine
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• 제39권1호
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• pp.28-32
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• 2012

Objective: This study was performed to assess the prognostic value of serum hCG, progesterone, and inhibin A levels measured at 11 days post-ET for predicting pregnancy outcome in women participating in IVF. Methods: Between May 2005 and April 2008, sera were obtained from 70 infertile women who underwent IVF-ET at 11 days post-ET and stored. HCG, progesterone, and inhibin A levels were measured by commercial enzyme-linked immunosorbent assay kits. The predictive accuracy of hCG, progesterone, and inhibin A levels for establishment of intrauterine pregnancy and ongoing pregnancy was calculated by receiver-operating characteristic curve analysis. Results: For the prediction of intrauterine and ongoing pregnancy, serum hCG was better than progesterone and inhibin A. The predictive performance of progesterone and inhibin A was similar. The serum progesterone and inhibin A levels were significantly correlated each other (r=0.915, p=0.010). Conclusion: A single measurement of the serum hCG level is sufficient to predict pregnancy outcome in IVF-ET patients.

• Asian Pacific Journal of Cancer Prevention
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• 제15권3호
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• pp.1339-1344
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• 2014

Aims: Alterations in mitochondrial DNA (mtDNA) have been implicated in carcinogenesis and tumor progression. We here evaluated the diagnostic and prognostic potential of mtDNA as a biomarker for breast cancer. Methods: Using multiplex real-time polymerase chain reaction, nuclear DNA (nDNA) and mtDNA levels in serum, buffy coat, tumor, and tumor-adjacent tissue samples from 50 breast cancer patients were determined and assessed for associations with clinicopathological features. To evaluate mtDNA as a biomarker for distinguishing between the four sample types, we created receiver operating characteristic (ROC) curves. Results: The mtDNA levels in buffy coat were significantly lower than in other sample types. Relative to tumor-adjacent tissue, reduced levels of mtDNA were identified in buffy coat and tumor tissue but not in serum. According to ROC curve analysis, mtDNA levels could be used to distinguish between buffy coat and tumor-adjacent tissue samples with good sensitivity (77%) and specificity (83%). Moreover, mtDNA levels in serum and tumor tissue were positively associated with cancer TMN stage. Conclusions: The mtDNA levels in blood samples may represent a promising, non-invasive biomarker in breast cancer patients. Additional, large-scale validation studies are required to establish the potential use of mtDNA levels in the early diagnosis and monitoring of breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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• pp.6819-6822
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• 2014

Background: The aim of this study was to evaluate the accuracy of a new scoring system in Korean patients with hematuria at high risk of bladder cancer. Materials and Methods: A total of 319 consecutive patients presenting with painless hematuria without a history of bladder cancer were analyzed, from the period of August 2012 to February 2014. All patients underwent clinical examination, and 22 patients with incomplete data were excluded from the final validation data set. The scoring system included four clinical parameters: age (${\geq}50$ = 2 vs. <50 =1), gender (male = 2 vs. female = 1), history of smoking (smoker/ex-smoker = 4 vs. non-smoker = 2) and nature of the hematuria (gross = 6 vs. microscopic = 2). Results: The area under the receiver-operating characteristic curve (95% confidence interval) of the scoring system was 0.718 (0.655-0.777). The calibration plot demonstrated a slight underestimation of bladder cancer probability, but the model had reasonable calibration. Decision curve analysis revealed that the use of model was associated with net benefit gains over the treat-all strategy. The scoring system performed well across a wide range of threshold probabilities (15%-45%). Conclusions: The scoring system developed is a highly accurate predictive tool for patients with hematuria. Although further improvements are needed, utilization of this system may assist primary care physicians and other healthcare practitioners in determining a patient's risk of bladder cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7315-7319
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• 2013

Background: The metastasis gene osteopontin (OPN) is subject to alternative splicing, which yields three messages, osteopontin-a, osteopontin-b and osteopontin-c. Osteopontin-c is selectively expressed in invasive, but not in noninvasive tumors. In the present study, we examined the expression of OPN-c in esophageal squamous cell carcinomas (ESCCs) and assessed its value as a diagnostic biomarker. Methods: OPN-c expression was assessed by immunohistochemistry in 63 ESCC samples and correlated with clinicopathologic factors. Expression was also examined in peripheral blood mononuclear cells (PBMCs) from 120 ESCC patients and 30 healthy subjects. The role of OPN-c mRNA as a tumor marker was investigated by receiver operating characteristic curve (ROC) analysis. Results: Immunohistochemistry showed that OPN-c was expressed in 30 of 63 cancer lesions (48%)and significantly associated with pathological T stage (P=0.038) and overall stage (P=0.023). Real time PCR showed that OPN-c mRNA was expressed at higher levels in the PBMCs of ESCC patients than in those of healthy subjects (P<0.0001) with a sensitivity as an ESCC biomarker of 86.7%. Conclusion: Our findings suggest that expression of OPN-c is significantly elevated in ESCCs and this upregulation could be a potential diagnostic marker.

• Clinical and Experimental Pediatrics
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• 제58권8호
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• pp.294-300
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• 2015

Purpose: It is difficult to differentiate between central precocious puberty (CPP) and premature thelarche (PT) in girls. The aim of this study was to investigate the diagnostic usefulness of pelvic ultrasonography to distinguish between CPP and PT in girls with early breast development. Methods: This study included girls with early breast development who visited the clinic between January 2012 and December 2013. Clinical, laboratory, and pelvic ultrasonographic data were evaluated. CPP and PT were confirmed using the gonadotropin-releasing hormone stimulation test. Results: A total of 248 girls aged 7-8 years were included, among whom 186 (75.0%) had CPP and 62 (25.0%) had PT. The uterine length, transverse diameter, fundus, volume, and cross-sectional area were significantly larger in the CPP group (uterine length, $2.45{\pm}0.50cm$ vs. $2.63{\pm}0.49cm$, P=0.015; uterine volume, $0.95{\pm}0.62cm^3$ vs. $1.35{\pm}0.76cm^3$, P<0.001). However, there were no differences in the fundus/cervix ratio and ovarian measurements. In receiver operating characteristic analysis, a uterine volume of at least $1.07cm^3$ was the most predictive parameter for CPP with an area under the curve of 0.670 (95% confidence interval, 0.593-0.747). Conclusion: Uterine measurements by pelvic ultrasonography in girls with early pubertal development were significantly larger in the CPP group. However, the diagnostic value of ultrasonographic parameters was not high because of a considerable overlap of values between the two groups. Therefore, pelvic ultrasonography in combination with clinical and laboratory tests may be useful to distinguish between CPP and PT in girls.

• 응용통계연구
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• 제31권5호
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• pp.573-585
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• 2018

본 연구에서는 제 2형 당뇨(type 2 diabetes mellitus)의 발병 확률을 예측하기 위해 11가지 위험요인을 가지고 로지스틱 회귀모형과 순수 베이지안 분류기 모형에 적합시킨다. 그런 다음 이를 시각적으로 쉽게 이해하는데 도움을 주는 노모그램 구축 방법을 소개한다. 분석은 2013-2015년 6기 국민건강영양조사 데이터를 가지고 분석하였다. 또 로지스틱 회귀모형에 세 가지 상호작용 항을 넣어 분석의 질을 높이고자 하였고 베이지안 노모그램에 left-aligned 방법을 사용하여 비교하기 쉽게 만들었다. 최종적으로 두 노모그램을 비교하고 효용성을 알아보았다. 마지막으로 ROC 곡선을 이용하여 노모그램이 적절한지 검증하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8625-8628
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• 2016

Background: Central lymph node metastasis(CLNM) is common in papillary thyroid microcarcinoma (PTMC). The aim of this study was to define the pathohistologic risk grading based on surgical outcomes. Materials and Methods: Statistical analysis was performed to figure out the optimal cut-off values of size in preoperative ultrasound images for defining the risk of CLNM in papillary thyroid microcarcinoma. Receiver operating characteristic curves (ROC) studies were carried out to determine the cutoff value(s) for the predictor(s). All the patients were divided into two groups according to the above size and the clinic-pathological and immunohistochemical parameters were compared to determine the significance of findings. Results: The optimal cut-off value of tumor size to predict the risk of CLNM in papillary thyroid microcarcinoma was 0.575 cm (area under the curve 0.721) according to the ROC curves. Significant differences were observed on the multifocality, extrathyroidal extension and central lymph node metastasis between two groups which were divided according to the tumor size by the cutoff values. Patients in two groups showed different positive rate and intensity of Ki67. Conclusions: The size of PTMC in ultrasound images are helpful to predict the aggressiveness of the tumors, it could be an easy predictor for PTMC prognosis and assist us to choose treatment.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.707-712
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• 2015

Background: To evaluate use of magnetic resonance imaging (MRI) and a logistic model including risk factors for lymph node metastasis for improved diagnosis. Materials and Methods: The subjects were 176 patients with rectal cancer who underwent preoperative MRI. The longest lymph node diameter was measured and a cut-off value for positive lymph node metastasis was established based on a receiver operating characteristic (ROC) curve. A logistic model was constructed based on MRI findings and risk factors for lymph node metastasis extracted from logistic-regression analysis. The diagnostic capabilities of MRI alone and those of the logistic model were compared using the area under the curve (AUC) of the ROC curve. Results: The cut-off value was a diameter of 5.47 mm. Diagnosis using MRI had an accuracy of 65.9%, sensitivity 73.5%, specificity 61.3%, positive predictive value (PPV) 62.9%, and negative predictive value (NPV) 72.2% [AUC: 0.6739 (95%CI: 0.6016-0.7388)]. Age (<59) (p=0.0163), pT (T3+T4) (p=0.0001), and BMI (<23.5) (p=0.0003) were extracted as independent risk factors for lymph node metastasis. Diagnosis using MRI with the logistic model had an accuracy of 75.0%, sensitivity 72.3%, specificity 77.4%, PPV 74.1%, and NPV 75.8% [AUC: 0.7853 (95%CI: 0.7098-0.8454)], showing a significantly improved diagnostic capacity using the logistic model (p=0.0002). Conclusions: A logistic model including risk factors for lymph node metastasis can improve the accuracy of MRI diagnosis of rectal cancer.