• Title/Summary/Keyword: Likelihood ratios

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Modeling Traffic Accident Occurrence Involving Child Pedestrians at School Zone (공간적 특성을 고려한 어린이 교통사고 모형 개발)

  • BEAK, Tea Hun;Son, Seulki;PARK, Byung Ho
    • Journal of Korean Society of Transportation
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    • v.34 no.6
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    • pp.489-498
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    • 2016
  • The objective of this study is to develop road traffic accident model involving child pedestrian especially at school zones and its surrounding area. The analysis is based upon traffic accident data collected near sixty elementary schools in City of Cheongju during 2012 and 2014. This study results in two statistical models ; one is to predict the number of road traffic accidents involving children, and the other is to predict EPDO(Equivalent Prperty Damage Only). These models are represented as Poisson models. which are statistically significant with the likelihood ratios of 0.533 and 0.273. The common explanatory variables of these models are the ratio of road section with more than 4 lanes, the number of entrance and exit, the number of signalized crosswalk in school zone, the number of school zone signage including road surface marking, and the number of speed limit signs. The specific variables are the length of road stretch in school zone, the number of reflector mirrors, and the number of signalized crosswalk outside school zone. It is concluded that these types of road safety facilities can reduce the number of traffic accidents involving children at school zones and its surrounding area.

A Systematic Review of MRI, Scintigraphy, FDG-PET and PET/CT for Diagnosis of Multiple Myeloma Related Bone Disease - Which is Best?

  • Weng, Wan-Wen;Dong, Meng-Jie;Zhang, Jun;Yang, Jun;Xu, Qin;Zhu, Yang-Jun;Liu, Ning-Hu
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.22
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    • pp.9879-9884
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    • 2014
  • Aim: The purpose of the current study was to conduct a systematic review of the published literature to evaluate the diagnostic accuracy of FDG-PET, PTE/CT, MRI and scintigraphy for multiple myeloma related bone disease. Methods: Through a search of PubMed, EMBASE, and the Cochrane Library, two reviewers independently assessed the methodological quality of each study. We estimated pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), and two sample Z-tests were conducted to evaluate for differences in sensitivity, specificity, area under the curve (AUC), and the $Q^*$ index between any two diagnostic modalities. Results: A total of 17 studies were reviewed. The MRI had a pooled sensitivity of 0.88, specificity of 0.68, AUC of 0.897, and $Q^*$ index of 0.828, whereas for MIBI, the corresponding values were 0.98, 0.90, 0.991, and 0.962, respectively, and for bone scan, they were 066, 0.83, 0.805, and 0.740, respectively. The corresponding values of MIBI were 0.98, 0.90, 0.991, and 0.962, respectively. For PET and PET/CT, the values were 0.91, 0.69, 0.927 and 0.861, respectively. Statistically significant differences were not found in the sensitivity, specificity, AUC, and $Q^*$ index between MRI, scintigraphy, FDG-PET and PET/CT. Conclusions: On the condition that X ray is taken as a reference in our study, we suggested that FDG-PET, PTE/CT, MRI and scintigraphy are all associated with high detection rate of bone disease in patients with MM. Thus, in clinical practice, it is recommended that we could choose these tests according to the condition of the patient.

Lifestyle and Metabolic Syndrome among Male Workers in an Electronics Research and Development Company (한 전자제품 연구소 남자 종사자들의 생활습관실천과 대사증후군의 관련성)

  • Myong, Jun-Pyo;Kim, Hyoung-Ryoul;Kim, Yong-Kyu;Koo, Jung-Wan;Park, Chung-Yill
    • Journal of Preventive Medicine and Public Health
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    • v.42 no.5
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    • pp.331-336
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    • 2009
  • Objectives : The objectives of this study were to determine the relationship between lifestyle-implementation and metabolic syndrome in an electronics research and development company, and to provide a foundation for health providers of health management programs for setting priorities. Methods : From July 1 to July 16, 2008 we carried out a descriptive cross-sectional survey. Consecutive workers of one R & D company in Seoul, Korea (N=2,079) were enrolled in study. A checklist for lifestyle (from the National Health Insurance Corporation) consisted of questions regarding diet, drinking, smoking and exercise. After the survey, researchers obtained data from health profiles for metabolic syndrome(waist-circumference, triglycerides, HDL cholesterol, blood pressure and fasting blood sugar level). Lifestyle was recorded as good or not good. Statistical analysis of metabolic syndrome and the lifestyle of subjects was done using multiple logistic regression analysis. Results : The prevalence of metabolic syndrome in our study gropu was 13.3% (N=277). After adjustment for age, the adjusted odds ratios (odds ratio, 95% confidence intervals) for metabolic syndrome increased in proportion to the number of bad habits: two (1.72, 1.23-2.44), three (2.47, 1.73-3.56), and four (3.63, 2.03-6.34). Relative to subjects eating both vegetables and meat', the OR for 'meat' eaters was 1.66 (1.18-2.31). Compared with 'nonsmokers and ever-smoker', the OR for 'current-smoker' was 1.62 (1.25-2.10). Compared with 'Healthy drinker', the OR for 'unhealthy drinker' was 1.38 (1.05-1.83). Conclusions : Poor lifestyle was associated with an increased likelihood of metabolic syndrome. These findings suggest that lifestyle-based occupational health interventions for young employees should include a specific diet, smoking cessation, and healthy-drinking programs.

Comparison of α1-Antitrypsin, α1-Acid Glycoprotein, Fibrinogen and NOx as Indicator of Subclinical Mastitis in Riverine Buffalo (Bubalus bubalis)

  • Guha, Anirban;Guha, Ruby;Gera, Sandeep
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.6
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    • pp.788-794
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    • 2013
  • Mastitis set apart as clinical and sub clinical is a disease complex of dairy cattle, with sub clinical being the most important economically. Of late, laboratories showed interest in developing biochemical markers to diagnose sub clinical mastitis (SCM) in herds. Many workers reported noteworthy alternation of acute phase proteins (APPs) and nitric oxide, (measured as nitrate+nitrite = NOx) in milk due to intra-mammary inflammation. But, the literature on validation of these parameters as indicators of SCM, particularly in riverine milch buffalo (Bubalus bubalis) milk is inadequate. Hence, the present study focused on comparing several APPs viz. ${\alpha}_1$-anti trypsin, ${\alpha}_1$-acid glycoprotein, fibrinogen and NOx as indicators of SCM in buffalo milk. These components in milk were estimated using standardized analytical protocols. Somatic cell count (SCC) was done microscopically. Microbial culture was done on 5% ovine blood agar. Of the 776 buffaloes (3,096 quarters) sampled, only 347 buffaloes comprising 496 quarters were found positive for SCM i.e. milk culture showed growth in blood agar with $SCC{\geq}2{\times}10^5$ cells/ml of milk. The cultural examination revealed Gram positive bacteria as the most prevalent etiological agent. It was observed that ${\alpha}_1$-anti trypsin and NOx had a highly significant (p<0.01) increase in SCM milk, whereas, the increase of ${\alpha}_1$-acid glycoprotein in infected milk was significant (p<0.05). Fibrinogen was below detection level in both healthy and SCM milk. The percent sensitivity, specificity and accuracy, predictive values and likelihood ratios were calculated taking bacterial culture examination and $SCC{\geq}2{\times}10^5$ cells/ml of milk as the benchmark. Udder profile correlation coefficient was also used. Allowing for statistical and epidemiological analysis, it was concluded that ${\alpha}_1$-anti trypsin indicates SCM irrespective of etiology, whereas ${\alpha}_1$-acid glycoprotein better diagnosed SCM caused by gram positive bacteria. NOx did not prove to be a good indicator of SCM. It is recommended measuring both ${\alpha}_1$-anti trypsin and ${\alpha}_1$-acid glycoprotein in milk to diagnose SCM in buffalo irrespective of etiology.

Accuracy of Combined Visual Inspection with Acetic Acid and Cervical Cytology Testing as a Primary Screening Tool for Cervical Cancer: a Systematic Review and Meta-Analysis

  • Chanthavilay, Phetsavanh;Mayxay, Mayfong;Phongsavan, Keokedthong;Marsden, Donald E;White, Lisa J;Moore, Lynne;Reinharz, Daniel
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.14
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    • pp.5889-5897
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    • 2015
  • Background: The performance of combined testing visual inspection with acetic acid (VIA) and cervical cytology tests might differ from one setting to another. The average estimate of the testing accuracy across studies is informative, but no meta-analysis has been carried out to assess this combined method. Objective: The objective of this study was to estimate the average sensitivity and specificity of the combined VIA and cervical cytology tests for the detection of cervical precancerous lesions. Materials and Methods: We conducted a systematic review and a meta-analysis, according to the Cochrane Handbook for Systematic Review of Diagnostic Test Accuracy. We considered two cases. In the either-positive result case, a positive result implies positivity in at least one of the tests. A negative result implies negativity in both tests. In the both-positive case, a positive result implies having both tests positive. Eligible studies were identified using Pubmed, Embase, Website of Science, CINHAL and COCRANE databases. True positive, false positive, false negative and true negative values were extracted. Estimates of sensitivity and specificity, positive and negative likelihood (LR) and diagnostic odds ratios (DOR) were pooled using a hierarchical random effect model. Hierarchical summary receiver operating characteristics (HSROC) were generated and heterogeneity was verified through covariates potentially influencing the diagnostic odds ratio. Findings: Nine studies fulfilled inclusion criteria and were included in the analysis. Pooled estimates of the sensitivities of the combined tests in either-positive and both-positive cases were 0.87 (95% CI: 0.83-0.90) and 0.38 (95% CI: 0.29-0.48), respectively. Corresponding specificities were 0.79 (95% CI: 0.63-0.89) and 0.98 (95% CI: 0.96-0.99) respectively. The DORs of the combined tests in either-positive or both-positive result cases were 27.7 (95% CI: 12.5-61.5) and 52 (95% CI: 22.1-122.2), respectively. When including only articles without partial verification bias and also a high-grade cervical intraepithelial neoplasia as a threshold of the disease, DOR of combined test in both-positive result cases remained the highest. However, DORs decreased to 12.1 (95% CI: 6.05-24.1) and 13.8 (95% CI: 7.92-23.9) in studies without partial verification bias for the combined tests in the either-positive and both-positive result cases, respectively. The screener, the place of study and the size of the population significantly influenced the DOR of combined tests in the both-positive result case in restriction analyses that considered only articles with CIN2+ as disease threshold. Conclusions: The combined test in the either-positive result case has a high sensitivity, but a low specificity. These results suggest that the combined test should be considered in developing countries as a primary screening test if facilities exist to confirm, through colposcopy and biopsy, a positive result.

Predicting the success of CDM Registration for Hydropower Projects using Logistic Regression and CART (로그 회귀분석 및 CART를 활용한 수력사업의 CDM 승인여부 예측 모델에 관한 연구)

  • Park, Jong-Ho;Koo, Bonsang
    • Korean Journal of Construction Engineering and Management
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    • v.16 no.2
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    • pp.65-76
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    • 2015
  • The Clean Development Mechanism (CDM) is the multi-lateral 'cap and trade' system endorsed by the Kyoto Protocol. CDM allows developed (Annex I) countries to buy CER credits from New and Renewable (NE) projects of non-Annex countries, to meet their carbon reduction requirements. This in effect subsidizes and promotes NE projects in developing countries, ultimately reducing global greenhouse gases (GHG). To be registered as a CDM project, the project must prove 'additionality,' which depends on numerous factors including the adopted technology, baseline methodology, emission reductions, and the project's internal rate of return. This makes it difficult to determine ex ante a project's acceptance as a CDM approved project, and entails sunk costs and even project cancellation to its project stakeholders. Focusing on hydro power projects and employing UNFCCC public data, this research developed a prediction model using logistic regression and CART to determine the likelihood of approval as a CDM project. The AUC for the logistic regression and CART model was 0.7674 and 0.7231 respectively, which proves the model's prediction accuracy. More importantly, results indicate that the emission reduction amount, MW per hour, investment/Emission as crucial variables, whereas the baseline methodology and technology types were insignificant. This demonstrates that at least for hydro power projects, the specific technology is not as important as the amount of emission reductions and relatively small scale projects and investment to carbon reduction ratios.

Risk Factors of Falls among Korean Elderly (한국노인의 낙상 요인 연구)

  • Yeom, Jihye;Na, Hang-Jin
    • 한국노년학
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    • v.32 no.2
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    • pp.577-592
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    • 2012
  • The purpose of this study is to examine which factors determine fall experience among Korean elderly. To achieve this purpose, it uses the Korean Longitudinal Study of Aging(KLoSA), wave 1 and 2. Participants aged 65 from wave 1 were selected. From wave 2, a dependent variable was selected and it was fall experiences since the first interview in 2006. Other than this variable, all independent variables were selected from wave 1. In analyses, x2 or t-test were conducted to examine whether independent variables significantly differ between falls and no falls. Then, since a dependent variable consisted of two categories-falls or no falls, multiple logistic regressions were run. Female, using hearing aid, having two diseases, having three or more diseases, depression, and exercise 5 times/a week or more elevated the odds ratios of fall experience. compared to their reference categories. Particularly, if Korean elderly had three or more diseases or depression, their likelihood of fall experience would have about 2 times higher than their reference categories. In conclusion, health practitioners should make the elderly be recognized how much these risk factors are important to falls. Also, Korean government should support Korean elderly having these risk factors to prevent them from falling.

The Prediction of Export Credit Guarantee Accident using Machine Learning (기계학습을 이용한 수출신용보증 사고예측)

  • Cho, Jaeyoung;Joo, Jihwan;Han, Ingoo
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.83-102
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    • 2021
  • The government recently announced various policies for developing big-data and artificial intelligence fields to provide a great opportunity to the public with respect to disclosure of high-quality data within public institutions. KSURE(Korea Trade Insurance Corporation) is a major public institution for financial policy in Korea, and thus the company is strongly committed to backing export companies with various systems. Nevertheless, there are still fewer cases of realized business model based on big-data analyses. In this situation, this paper aims to develop a new business model which can be applied to an ex-ante prediction for the likelihood of the insurance accident of credit guarantee. We utilize internal data from KSURE which supports export companies in Korea and apply machine learning models. Then, we conduct performance comparison among the predictive models including Logistic Regression, Random Forest, XGBoost, LightGBM, and DNN(Deep Neural Network). For decades, many researchers have tried to find better models which can help to predict bankruptcy since the ex-ante prediction is crucial for corporate managers, investors, creditors, and other stakeholders. The development of the prediction for financial distress or bankruptcy was originated from Smith(1930), Fitzpatrick(1932), or Merwin(1942). One of the most famous models is the Altman's Z-score model(Altman, 1968) which was based on the multiple discriminant analysis. This model is widely used in both research and practice by this time. The author suggests the score model that utilizes five key financial ratios to predict the probability of bankruptcy in the next two years. Ohlson(1980) introduces logit model to complement some limitations of previous models. Furthermore, Elmer and Borowski(1988) develop and examine a rule-based, automated system which conducts the financial analysis of savings and loans. Since the 1980s, researchers in Korea have started to examine analyses on the prediction of financial distress or bankruptcy. Kim(1987) analyzes financial ratios and develops the prediction model. Also, Han et al.(1995, 1996, 1997, 2003, 2005, 2006) construct the prediction model using various techniques including artificial neural network. Yang(1996) introduces multiple discriminant analysis and logit model. Besides, Kim and Kim(2001) utilize artificial neural network techniques for ex-ante prediction of insolvent enterprises. After that, many scholars have been trying to predict financial distress or bankruptcy more precisely based on diverse models such as Random Forest or SVM. One major distinction of our research from the previous research is that we focus on examining the predicted probability of default for each sample case, not only on investigating the classification accuracy of each model for the entire sample. Most predictive models in this paper show that the level of the accuracy of classification is about 70% based on the entire sample. To be specific, LightGBM model shows the highest accuracy of 71.1% and Logit model indicates the lowest accuracy of 69%. However, we confirm that there are open to multiple interpretations. In the context of the business, we have to put more emphasis on efforts to minimize type 2 error which causes more harmful operating losses for the guaranty company. Thus, we also compare the classification accuracy by splitting predicted probability of the default into ten equal intervals. When we examine the classification accuracy for each interval, Logit model has the highest accuracy of 100% for 0~10% of the predicted probability of the default, however, Logit model has a relatively lower accuracy of 61.5% for 90~100% of the predicted probability of the default. On the other hand, Random Forest, XGBoost, LightGBM, and DNN indicate more desirable results since they indicate a higher level of accuracy for both 0~10% and 90~100% of the predicted probability of the default but have a lower level of accuracy around 50% of the predicted probability of the default. When it comes to the distribution of samples for each predicted probability of the default, both LightGBM and XGBoost models have a relatively large number of samples for both 0~10% and 90~100% of the predicted probability of the default. Although Random Forest model has an advantage with regard to the perspective of classification accuracy with small number of cases, LightGBM or XGBoost could become a more desirable model since they classify large number of cases into the two extreme intervals of the predicted probability of the default, even allowing for their relatively low classification accuracy. Considering the importance of type 2 error and total prediction accuracy, XGBoost and DNN show superior performance. Next, Random Forest and LightGBM show good results, but logistic regression shows the worst performance. However, each predictive model has a comparative advantage in terms of various evaluation standards. For instance, Random Forest model shows almost 100% accuracy for samples which are expected to have a high level of the probability of default. Collectively, we can construct more comprehensive ensemble models which contain multiple classification machine learning models and conduct majority voting for maximizing its overall performance.

Long-term outcomes of infantile spasms (영아 연축 환아의 장기적 예후에 관한 고찰)

  • Oh, Seak Hee;Lee, Eun-Hye;Joung, Min-Hee;Yum, Mi-Sun;Ko, Tae-Sung
    • Clinical and Experimental Pediatrics
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    • v.53 no.1
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    • pp.80-84
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    • 2010
  • Purpose : The aims of this study were to investigate the long-term outcomes in children with infantile spasms (IS) and to identify the prognostic factors influencing their neurodevelopment. Methods : We retrospectively evaluated seventy two children over five years old who were treated for IS at Asan Medical Center, Seoul, Korea, between 1994 and 2007. Forty-three children were contacted by telephone or medical follow-up to assess their current neurodevelopmental status. Multiple logistic regression was used to calculate odds ratios (ORs) and 95% confidence interval (95% CIs) of risk factors for unfavorable outcomes.Results : The mean follow-up duration for these 43 children was $7.2{\pm}1.5$ years (range, 4.5 to 13.0 years). Of these, 13 (30.2%) had cryptogenic and 30 (69.8%) had symptomatic IS. Eleven (25.6%) children were initially treated with adrenocorticotrophic hormone (ACTH) therapy, with a mean treatment lag of $1.3{\pm}1.9$ months (range; 0.1 to 7.0 months). Eighteen (41.8%) children clinically responded to initial treatment, as shown by EEG response. Overall, 22 (51.2%) children had at least moderate neurodevelopmental disorders and 2 (4.8%) died. In univariate analysis, etiology (symptomatic) and poor electroclinical response to initial treatment were related to long-term unfavorable outcomes. In multivariate analysis, response to primary treatment was the sole significant independent risk factor with a high OR. Conclusion : Overall prognosis of children with IS was poor. Electroclinical non-responsiveness to initial treatment was related to unfavorable long-term outcomes, indicating that initial control of seizures may be important in reducing the likelihood of poor neurodevelopment.

The Usefulness of the Berlin Questionnaire as a Screening for Obstructive Sleep Apnea in a Sleep Clinic Population (수면 클리닉을 내원한 환자에서 폐쇄성수면무호흡의 선별을 위한 베를린 설문의 유용성)

  • Kang, Hyeon-Hui;Kang, Ji-Young;Lee, Sang-Haak;Moon, Hwa-Sik
    • Sleep Medicine and Psychophysiology
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    • v.18 no.2
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    • pp.82-86
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    • 2011
  • Objectives: The Berlin Questionnaire (BQ) has been used to help identify patients at high risk of having sleep apnea in primary care. But it has not been validated in a sleep clinic for Korean patients. The aim of this study is to evaluate the usefulness of the BQ as a screening tool for obstructive sleep apnea (OSA) for Korean patients in a sleep clinic. Methods: The BQ was prospectively applied to 121 subjects with OSA suspicion who visited to our sleep clinic. All subjects performed overnight polysomnography. OSA was defined as an apnea-hypopnea index (AHI) ${\geq}5$. We investigated the sensitivity, specificity, positive and negative predictive values of the BQ according to severity by AHI. Results: In 121 subjects, 73.6% were males, with a mean age of $48.8{\pm}13.0$ years. Twenty-five (20.6%) patients did not have OSA (AHI<5), 30 (25%) patients had mild OSA ($AHI{\geq}5$ and <15), 26 (21.4%) had moderate ($AHI{\geq}15$ and <30), and 40 (33%) had severe OSA ($AHI{\geq}30$). The BQ identified 69.4% of the patients as being at high risk for having OSA. The sensitivity and specificity of the BQ were 71.9% and 40%, for $AHI{\geq}5$, 75.8% and 38.2% for $AHI{\geq}15$, 77.5% and 34.6% for $AHI{\geq}30$, respectively. The positive and negative predictive values of the BQ were 82.1% and 27.0% for $AHI{\geq}5$, respectively. Positive and negative likelihood ratios were 1.2 and 0.7, and the overall diagnostic accuracy of the BQ was 65.3%, using an AHI cut-off of 5. Conclusion: Due to modest sensitivity and low specificity, the BQ does not seem to be an appropriate tool for identifying patients with obstructive sleep apnea in a sleep clinic population.