• Title/Summary/Keyword: Contingency table

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Risk Assessment of the Road Cut Slopes in Gyeoungnam based on Multiple Regression Analysis (다중회귀분석을 통한 경남 지방도로 절취사면의 안정성평가)

  • Kang, Tae-Seung;Um, Jeong-Gi
    • The Journal of Engineering Geology
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    • v.17 no.3
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    • pp.393-404
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    • 2007
  • The purpose of this study is to capture the essentials in survey and evaluation scheme which are able to assess the hazard of a rock slope systematically. Statistical analysis are performed on slope instability parameters related to failure of the rock slope. As the slope instability parameters, twelve survey items are considered such as tension crack, surface deformation, deformation of retaining structures, volume of existing failures, angles between strike of discontinuity and strike of cut slope face, angles between dip of discontinuity and dip of cut slope face, discontinuity condition, cut slope angle, rainfall or ground water level, excavation condition, drainage condition, reinforcement. A total of 233 road cut slopes located in Gyeongnam were considered. The stability of the road cut slopes were evaluated by estimating the slope instability index(SII) and corresponding stability rank. 126 rock slopes were selected to analyze statistical relation between SII and slope instability parameters. The multiple regression analysis was applied to derive statistical models which are able to predict the SII and corresponding slope stability rank. Also, its applicability was explored to predict the slope failures using the variables of slope instability parameters. The results obtained in this study clearly show that the methodology given in this paper have strong capabilities to evaluate the failures of the road cut slope effectively.

Statistical Analysis of Quality Control Data of Blood Components (혈액성분제제 품질관리 자료의 통계학적인 비교)

  • Kim, Chongahm;Seo, Dong Hee;Kwon, So Yong;Oh, Yuong Chul;Lim, Chae Seung;Jang, Choong Hoon;Kim, Soonduck
    • Korean Journal of Clinical Laboratory Science
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    • v.36 no.1
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    • pp.19-26
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    • 2004
  • According to increase of domestic blood components use, the quality control of blood components is necessary to support good products. The purpose of this study is used to provide the producing index of the good product as compared with the accuracy and validity for the distribution of the quality control data. The value of mean, standard deviation, 95% confidence interval and degree of normal distribution of data were calculated by univariate procedure, the value of monthly mean of each blood centers per items were compared by Analysis of Variance(ANOVA) test for the degree of distribution. When there was difference among the mean values, the Duncan's multiple range test was done to confirm the difference. Finally, methods for accessing accuracy and validity of the quality data was done by the Contingency table test. The quality data of five blood centers was showed to the normal distribution and it was in a acceptable range. For each blood centers, the monthly means of Hematocrit(Hct), Platelet(PLT) and pH were not significantly different except Hct of C center, PLT of B, D center and pH of A center. The quality data per items was graded according to quality to six level. As a result of the comparative analysis, the monthly means of Hct of C and E center was significantly different higher than that of D, B and A center. The monthly means of PLT of A center and pH of C center was significantly different higher than that of the others. In the accuracy and validity of the quality control data, C center for Hct, A center for PLT and C center for pH were better than the other. The C blood center was most satisfiable and stable in the quality control for blood component. If the quality control method used in C blood center is adopted in other blood centers, the prepared level of the blood component of the center will be improved partly.

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WRF-Based Short-Range Forecast System of the Korea Air Force : Verification of Prediction Skill in 2009 Summer (WRF 기반 공군 단기 수치 예보 시스템 : 2009년 하계 모의 성능 검증)

  • Byun, Ui-Yong;Hong, Song-You;Shin, Hyeyum;Lee, Ji-Woo;Song, Jae-Ik;Hahm, Sook-Jung;Kim, Jwa-Kyum;Kim, Hyung-Woo;Kim, Jong-Suk
    • Atmosphere
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    • v.21 no.2
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    • pp.197-208
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    • 2011
  • The objective of this study is to describe the short-range forecast system of the Korea Air Force (KAF) and to verificate its performace in 2009 summer. The KAF weather prediction model system, based on the Weather Research and Forecasting (WRF) model (i.e., the KAF-WRF), is configured with a parent domain overs East Asia and two nested domains with the finest horizontal grid size of 2 km. Each domain covers the Korean peninsula and South Korea, respectively. The model is integrated for 84 hour 4 times a day with the initial and boundary conditions from National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) data. A quantitative verification system is constructed for the East Asia and Korean peninsula domains. Verification variables for the East Asia domain are 500 hPa temperature, wind and geopotential height fields, and the skill score is calculated using the difference between the analysis data from the NCEP GFS model and the forecast data of the KAF-WRF model results. Accuracy of precipitation for the Korean penisula domain is examined using the contingency table that is made of the KAF-WRF model results and the KMA (Korea Meteorological Administraion) AWS (Automatic Weather Station) data. Using the verification system, the operational model and parallel model with updated version of the WRF model and improved physics process are quantitatively evaluated for the 2009 summer. Over the East Aisa region, the parallel experimental model shows the better performance than the operation model. Errors of the experimental model in 500 hPa geopotential height near the Tibetan plateau are smaller than errors in the operational model. Over the Korean peninsula, verification of precipitation prediction skills shows that the performance of the operational model is better than that of the experimental one in simulating light precipitation. However, performance of experimental one is generally better than that of operational one, in prediction.

A study of applying soil moisture for improving false alarm rates in monitoring landslides (산사태 모니터링 오탐지율 개선을 위한 토양수분자료 활용에 관한 연구)

  • Oh, Seungcheol;Jeong, Jaehwan;Choi, Minha;Yoon, Hongsik
    • Journal of Korea Water Resources Association
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    • v.54 no.12
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    • pp.1205-1214
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    • 2021
  • Precipitation is one of a major causes of landslides by rising of pore water pressure, which leads to fluctuations of soil strength and stress. For this reason, precipitation is the most frequently used to determine the landslide thresholds. However, using only precipitation has limitations in predicting and estimating slope stability quantitatively for reducing false alarm events. On the other hand, Soil Moisture (SM) has been used for calculating slope stability in many studies since it is directly related to pore water pressure than precipitation. Therefore, this study attempted to evaluate the appropriateness of applying soil moisture in determining the landslide threshold. First, the reactivity of soil saturation level to precipitation was identified through time-series analysis. The precipitation threshold was calculated using daily precipitation (Pdaily) and the Antecedent Precipitation Index (API), and the hydrological threshold was calculated using daily precipitation and soil saturation level. Using a contingency table, these two thresholds were assessed qualitatively. In results, compared to Pdaily only threshold, Goesan showed an improvement of 75% (Pdaily + API) and 42% (Pdaily + SM) and Changsu showed an improvement of 33% (Pdaily + API) and 44% (Pdaily + SM), respectively. Both API and SM effectively enhanced the Critical Success Index (CSI) and reduced the False Alarm Rate (FAR). In the future, studies such as calculating rainfall intensity required to cause/trigger landslides through soil saturation level or estimating rainfall resistance according to the soil saturation level are expected to contribute to improving landslide prediction accuracy.

Therapeutic Compliance for Calcium Supplements and Its Related Factors in Rural Osteoporotic Women (일부 농촌지역 여성 골다공증 환자의 칼슘보조제 치료순응도와 결정요인)

  • Chun, Byung-Yeol;Kam, Sin;Lee, Young-Ja;Lee, Sang-Won;Lee, Kyung-Eun;Lee, Young-Seok;Kim, Bong-Kee
    • Journal of agricultural medicine and community health
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    • v.26 no.2
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    • pp.111-132
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    • 2001
  • This study was conducted to examine the therapeutic compliance and its related factors in rural women with osteoporosis. A questionnaire survey was performed from April to May in 2000 for 140 osteoporotic patients who were diagnosed from April to June in 1999 through community health program. The study employed the health belief model for predicting and explaining sick role behavior. The analysis techniques employed included contingency table analysis and path analysis using LISREL. The major results of this study were as follows: Of the subjects, 12.1% were continuously complaint, 53.6% were intermittently compliant, and 34.3% were non- compliant to calcium supplement therapy. As the result of path analysis, the therapeutic compliance was significantly higher(${\mid}T{\mid}$ >2.0) as patients had higher perceived severity of disease, lower perceived barriers of treatment, and when patients thought their disease status as severe. As the patients had higher educational level, more experience of mass media contact or health education about osteoporosis, and when family had more concern for patient treatment, they had higher perceived susceptibility of complication(bone fracture)${\mid}T{\mid}$ >2.0). The patients had higher perceived severity(${\mid}T{\mid}$ >2.0) as they had more educational level, more advice for treatment from their doctors, and when family had more concern for their treatment. As the patients had more advice for treatment from their doctors and when family had more concern for their treatment, they had higher perceived benefit of treatment and lower perceived barriers to treatment(${\mid}T{\mid}$ >2.0). In order to improve the therapeutic compliance in rural osteoporotic women, it would be necessary that the patient should recognize their disease severity properly. And the perceived barriers should be removed through supportive environments for osteoporosis treatment such as doctor 's more advice and family 's more concern for treatment. In addition, effective and continuous management system for osteoporotic patients should be established.

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An Evaluation of the Use of Statistical Methods in the Journal of Tuberculosis and Respiratory Diseases ([결핵 및 호흡기질환] 게재 논문의 통계적 기법 활용에 대한 평가)

  • Koh, Won-Jung;Lee, Seung-Joon;Kang, Min Jong;Lee, Hun Jae
    • Tuberculosis and Respiratory Diseases
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    • v.57 no.2
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    • pp.168-179
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    • 2004
  • Background : The statistical analysis is an essential procedure ensuring that the results of researches are based on evidences rather than opinion. The purpose of this study is to evaluate which statistical techniques are used and whether these statistical methods are used appropriately or not in the journal of Tuberculosis and Respiratory Diseases. Materials and Methods : We reviewed 185 articles reported in the journal of Tuberculosis and Respiratory Diseases in 1999. We evaluated the validity of used statistical methods based upon the checklist that was developed on the basis of the guideline for statistical reporting in articles for medical journals by International Committee of Medical Journal Editors. Results : Among 185 articles, original articles and case reports were 110 (59.5%) and 61 (33.0%) respectively. In 112 articles excluding case reports and reviews, statistical techniques were used in 107 articles (95.5%). In 94 articles (83.9%) descriptive and inferential methods were used, while in 13 (11.6%) articles only descriptive methods were used. With the types of inferential statistical techniques, comparison of means was most commonly used (64/94, 68.1%), followed by contingency table (43/94, 45.7%) and correlation or regression (18/94, 19.1%). Among the articles in which descriptive methods were used, 83.2% (89/107) showed inappropriate central tendency and dispersion. In the articles in which inferential methods were used, improper methods were applied in 88.8% (79/89) and the most frequent misuse of statistical methods was inappropriate use of parametric methods (35/89, 39.3%). Only 14 articles (13.1%) were satisfactory in utilization of statistical methodology. Conclusion : Most of the statistical errors found in the journal were misuses of statistical methods related to basic statistics. This study suggests that researchers should be more careful when they describe and apply statistical methods and more extensive statistical refereeing system would be needed.

A Study on Therapeutic Compliance of Hypertensive Patients in a Rural Health Subcenter (일개 농촌지역 보건지소 고혈압 환자의 치료지속성)

  • Song, Min-Keun
    • Journal of agricultural medicine and community health
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    • v.27 no.1
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    • pp.155-164
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    • 2002
  • Hypertension is the most frequent disease of chronic circulatory diseases and major intermediate cause or risk of the cerebrovascular disease which is a leading cause of death in Korea. Therefore, management of hypertension is an important issue in Korean healthcare. Especially, therapeutic compliance of hypertensives is very important because the hypertensive patients should receive anti-hypertensive treatment as long as the condition exists. However, many patients drop out of treatment, which is a major problem that needs to be solved through a hypertension control program. This study was carried out to provide basic data and counter measule for the hypertension control program in the community which aimed to keep the patients receiving treatment continuously. In order to investigate compliance of hypertensive patients during three months follow-up and the rate of control of hypertension, the data were collected during February, 2001, by reviewing medical records of 295 hypertensive patients who had been registered to Gunnam-myeon health subcenter before November, 2000. The author also study the dropout reasons by interviewing 58 patients among 68 dropout patients. The results were as follows: 1. Among the 295 subjects, 108(36.6%) were male and 187(63.4%) were female. Statistically, female hypertensives had a higher mean age than male(64.6 vs 66.3, p<0.05). 2. The 54.9% of the patients took anti-hypertensive medicine continuously for the past three months. And 19.3% had drug intermittently, and 25.8% dropped out of treatment. 3. Among several variables, such as sex, age, health insurance, the time taken from a patient's village to the health subcenter, only the last one was found to be significantly related to therapeutic compliance in the contingency table analysis. 4. The dropout reasons by multiple response were as follows, 'no symptom or no problem' (23.9%), 'change to other hospitals'(19.4%), 'geographical barrier'(17.9%), 'change to a neighborhood drugstore' (14.9%), 'immobility'(7.5%), 'economic barrier'(6.0%), 'unsatisfactory services of the health subcenter'(4.4%). 5. The mean blood pressure of 295 subjects was $144.9{\pm}12.9/86.88{\pm}8.6mmHg$. 6. The 32.5% of the subjects were controlled below 140/90mmHg. Conclusions: In order to improve the low rates of treatment and control of hypertension in rural hypertensives, a more active and systematic hypertension control program, including out-reaching follow-up management, is required in rural area. Especially, for health education of hypertensive patients, emphasis should placed on correcting wrong attitude toward hypertension.

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The NCAM Land-Atmosphere Modeling Package (LAMP) Version 1: Implementation and Evaluation (국가농림기상센터 지면대기모델링패키지(NCAM-LAMP) 버전 1: 구축 및 평가)

  • Lee, Seung-Jae;Song, Jiae;Kim, Yu-Jung
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.18 no.4
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    • pp.307-319
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    • 2016
  • A Land-Atmosphere Modeling Package (LAMP) for supporting agricultural and forest management was developed at the National Center for AgroMeteorology (NCAM). The package is comprised of two components; one is the Weather Research and Forecasting modeling system (WRF) coupled with Noah-Multiparameterization options (Noah-MP) Land Surface Model (LSM) and the other is an offline one-dimensional LSM. The objective of this paper is to briefly describe the two components of the NCAM-LAMP and to evaluate their initial performance. The coupled WRF/Noah-MP system is configured with a parent domain over East Asia and three nested domains with a finest horizontal grid size of 810 m. The innermost domain covers two Gwangneung deciduous and coniferous KoFlux sites (GDK and GCK). The model is integrated for about 8 days with the initial and boundary conditions taken from the National Centers for Environmental Prediction (NCEP) Final Analysis (FNL) data. The verification variables are 2-m air temperature, 10-m wind, 2-m humidity, and surface precipitation for the WRF/Noah-MP coupled system. Skill scores are calculated for each domain and two dynamic vegetation options using the difference between the observed data from the Korea Meteorological Administration (KMA) and the simulated data from the WRF/Noah-MP coupled system. The accuracy of precipitation simulation is examined using a contingency table that is made up of the Probability of Detection (POD) and the Equitable Threat Score (ETS). The standalone LSM simulation is conducted for one year with the original settings and is compared with the KoFlux site observation for net radiation, sensible heat flux, latent heat flux, and soil moisture variables. According to results, the innermost domain (810 m resolution) among all domains showed the minimum root mean square error for 2-m air temperature, 10-m wind, and 2-m humidity. Turning on the dynamic vegetation had a tendency of reducing 10-m wind simulation errors in all domains. The first nested domain (7,290 m resolution) showed the highest precipitation score, but showed little advantage compared with using the dynamic vegetation. On the other hand, the offline one-dimensional Noah-MP LSM simulation captured the site observed pattern and magnitude of radiative fluxes and soil moisture, and it left room for further improvement through supplementing the model input of leaf area index and finding a proper combination of model physics.