• Title/Summary/Keyword: Z-score Analysis

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Risk Factors and Clinical Outcomes of Brain Reperfusion Injury after Mechanical Thrombectomy for Ischemic Stroke (기계적 혈전제거술을 시행한 허혈성 뇌졸중 환자의 뇌재관류 손상 위험요인과 임상결과)

  • Moon, Ji Hyun;Choi, Hye-Ran
    • Journal of Korean Biological Nursing Science
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    • v.23 no.3
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    • pp.217-226
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    • 2021
  • Purpose: The aim of this study was to investigate the risk factors for brain reperfusion injury in ischemic stroke patients and to analyze the clinical outcomes. Methods: A retrospective study was conducted in 168 patients who underwent mechanical thrombectomy. The data were analyzed using descriptive statistics, t-test, Mann-Whitney U test, Chi-Square test, Fisher's exact test, and logistic regression with IBM SPSS/WIN 24.0. Results: Brain reperfusion injury occurred in 67 patients (39.9%) with a low favored outcome (𝛘2=6.01, p=.014). On multivariable analysis, blood urea nitrogen (Odds ratio [OR]=1.14, 95% Confidence interval [CI]=1.06-1.23), aphasia (OR=6.16, CI=1.62-23.40), anosognosia (OR=4.84, CI=1.13-20.79), presence of both aphasia and anosognosia (OR=7.33, CI=1.20-44.60), and time required to achieve targeted blood pressure (OR=1.00, CI=1.00-1.00) were identified as risk factors for brain reperfusion injury. A statistically significant difference was detected in clinical outcomes, including hemorrhagic transformation (𝛘2=6.32, p=.012), intensive care unit length of stay (Z=-2.08, p=.038), National Institute of Health Stroke scale score at discharge (Z=-3.14, p=.002), and modified Rankin Scale score at discharge (Z=-2.93, p=.003). Conclusion: This study identified the risk factors and presented the clinical outcomes of brain reperfusion injury. It is necessary to consider these risk factors for evaluating the patients and to establish nursing interventions and strategies.

Intercomparison and Determination of Trace Elements in Urban Dust by Neutron Activation Analysis (중성자방사화분석법을 이용한 대기분진중의 미량원소 비교분석)

  • Chung, Yong-Sam;Moon, Jong-Hwa;Kim, Sun-Ha;Park, Kwang-Won;Kang, Sang-Hun
    • Analytical Science and Technology
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    • v.13 no.2
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    • pp.179-188
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    • 2000
  • Trace elements in air samples artificially loaded on filters with urban dust and the bulk material of urban dust as an environmental sample were determined non-destructively using instrumental neutron activation analysis. Standard reference material (Urban Dust, SRM 1648) of the National Institute of Standard and Technology was used for the analytical quality control. The relative error for 37 elements was less than 15% and the standard deviation was less than 10%. 29 elements in the urban dust and 21 elements in the loaded filter sample were determined respectively. To evaluate the proficiency and reliability of the measurement, data intercomparison was performed and 39 analytical laboratories participated in the analysis using different analytical methods; neutron activation analysis, particle induced X-ray emission analysis, X-ray fluorescence analysis and atomic absorption spectrometry. Z-scores were calculated using the standard deviation of the laboratorie's mean as target standard deviation, and a good result was obtained that the values fall between -1 and +1 except some elements.

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A Study on the Application of Outlier Analysis for Fraud Detection: Focused on Transactions of Auction Exception Agricultural Products (부정 탐지를 위한 이상치 분석 활용방안 연구 : 농수산 상장예외품목 거래를 대상으로)

  • Kim, Dongsung;Kim, Kitae;Kim, Jongwoo;Park, Steve
    • Journal of Intelligence and Information Systems
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    • v.20 no.3
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    • pp.93-108
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    • 2014
  • To support business decision making, interests and efforts to analyze and use transaction data in different perspectives are increasing. Such efforts are not only limited to customer management or marketing, but also used for monitoring and detecting fraud transactions. Fraud transactions are evolving into various patterns by taking advantage of information technology. To reflect the evolution of fraud transactions, there are many efforts on fraud detection methods and advanced application systems in order to improve the accuracy and ease of fraud detection. As a case of fraud detection, this study aims to provide effective fraud detection methods for auction exception agricultural products in the largest Korean agricultural wholesale market. Auction exception products policy exists to complement auction-based trades in agricultural wholesale market. That is, most trades on agricultural products are performed by auction; however, specific products are assigned as auction exception products when total volumes of products are relatively small, the number of wholesalers is small, or there are difficulties for wholesalers to purchase the products. However, auction exception products policy makes several problems on fairness and transparency of transaction, which requires help of fraud detection. In this study, to generate fraud detection rules, real huge agricultural products trade transaction data from 2008 to 2010 in the market are analyzed, which increase more than 1 million transactions and 1 billion US dollar in transaction volume. Agricultural transaction data has unique characteristics such as frequent changes in supply volumes and turbulent time-dependent changes in price. Since this was the first trial to identify fraud transactions in this domain, there was no training data set for supervised learning. So, fraud detection rules are generated using outlier detection approach. We assume that outlier transactions have more possibility of fraud transactions than normal transactions. The outlier transactions are identified to compare daily average unit price, weekly average unit price, and quarterly average unit price of product items. Also quarterly averages unit price of product items of the specific wholesalers are used to identify outlier transactions. The reliability of generated fraud detection rules are confirmed by domain experts. To determine whether a transaction is fraudulent or not, normal distribution and normalized Z-value concept are applied. That is, a unit price of a transaction is transformed to Z-value to calculate the occurrence probability when we approximate the distribution of unit prices to normal distribution. The modified Z-value of the unit price in the transaction is used rather than using the original Z-value of it. The reason is that in the case of auction exception agricultural products, Z-values are influenced by outlier fraud transactions themselves because the number of wholesalers is small. The modified Z-values are called Self-Eliminated Z-scores because they are calculated excluding the unit price of the specific transaction which is subject to check whether it is fraud transaction or not. To show the usefulness of the proposed approach, a prototype of fraud transaction detection system is developed using Delphi. The system consists of five main menus and related submenus. First functionalities of the system is to import transaction databases. Next important functions are to set up fraud detection parameters. By changing fraud detection parameters, system users can control the number of potential fraud transactions. Execution functions provide fraud detection results which are found based on fraud detection parameters. The potential fraud transactions can be viewed on screen or exported as files. The study is an initial trial to identify fraud transactions in Auction Exception Agricultural Products. There are still many remained research topics of the issue. First, the scope of analysis data was limited due to the availability of data. It is necessary to include more data on transactions, wholesalers, and producers to detect fraud transactions more accurately. Next, we need to extend the scope of fraud transaction detection to fishery products. Also there are many possibilities to apply different data mining techniques for fraud detection. For example, time series approach is a potential technique to apply the problem. Even though outlier transactions are detected based on unit prices of transactions, however it is possible to derive fraud detection rules based on transaction volumes.

Comparison of Meteorological Drought Indices Using Past Drought Cases of Taebaek and Sokcho (태백, 속초 과거 가뭄사례를 이용한 기상학적 가뭄지수의 비교 고찰)

  • Kang, Dong Ho;Nam, Dong Ho;Kim, Byung Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.6
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    • pp.735-742
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    • 2019
  • Drought is a social phenomenon in which the degree of perception varies depending on the affected factors, and is defined as various relative concepts such as meteorological drought, hydrological drought, agricultural drought, and climatological drought. In this study, a comparative analysis of meteorological drought among variously defined droughts was conducted and the applicability of the drought index was examined by comparing the actual drought cases and the results of meteorological drought index analysis. In order to compare the drought index, we used standardized Precipitation Index (SPI), China-Z Index (CZI), Modified CZI (MCZI) and Z-Score Index Respectively. Four drought indices were used for the Taebaek and Sokcho areas. The drought index was analyzed using the meteorological data from 1986 to 2015 for a duration of 3 months. As a result of the analysis, the SPI drought index was analyzed to be highly reproducible for the case of drought with past limited water series. In the case of CZI and MCZI drought indices, the number of extreme dry occurrences is similar to that of the past cases, but the reproducibility is low for the actual drought years. In the case of ZSI drought index, it is analyzed that the number of occurrences and the comparison with the past cases are inferior in reproducibility. For the meteorological drought index using precipitation, it would be effective to use the SPI drought index with the highest reproducibility and the past drought case.

Observer Preferable Sharpness Enhancement Considering Distributions of Edge Characteristics (경계선 특성을 고려한 관측자 선호 선예도 개선 방법)

  • 홍상기;정재영;김대희;조맹섭
    • Proceedings of the IEEK Conference
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    • 2002.06d
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    • pp.275-278
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    • 2002
  • Sharpness enhancement, which strengthen the edge(high frequency) of image, is widely studied for image processing research area. In this paper, psychophysical experiment is conducted by the 20 observers with simple linear unsharp masking for sharpness enhancement. The experimental results extracted using z-score analysis and linear regression suggests observer preferable sharpness enhancement method for digital television.

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Mortality Reduction in Major Trauma Patients after Establishment of a Level I Trauma Center in Korea: A Single-Center Experience

  • Roh, Young Il;Kim, Hyung Il;Cha, Yong Sung;Cha, Kyoung-Chul;Kim, Hyun;Lee, Kang Hyun;Hwang, Sung Oh;Kim, Oh Hyun
    • Journal of Trauma and Injury
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    • v.30 no.4
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    • pp.131-139
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    • 2017
  • Purpose: Trauma systems have been shown to decrease injury-related mortality. The present study aimed to compare the mortality rates of patients with major trauma (injury severity score >15) treated before and after the establishment of a level I trauma center. Methods: During this 20-month study, participants were divided into pre-trauma center and trauma center groups, and trauma and injury severity score (TRISS) method was used to compare mortality rates during 10-month periods before and after the establishment of the trauma center (October 2013 to July 2014 vs. October 2014 to July 2015). Results: Of the 541 total participants, 278 (51.5%) visited after the establishment of the trauma center. The Z and W statistics indicated better outcomes in the trauma center group than in the pre-trauma center group (Z statistic, 2.635 vs. -0.700; W statistic, 4.640). The trauma center group also exhibited meaningful reductions in the time interval from the emergency department (ED) visit to emergency surgery (118.0 minutes vs. 142.5 minutes, p=0.020) and the interval from the ED visit to intensive care unit admission (202.0 minutes vs. 259.0 minutes, p=0.035) relative to the pre-trauma center group. Conclusions: The TRISS and multivariate analysis revealed significant improvements in survival rates in the trauma center group, compared to the pre-trauma center group.

Efficacy and Tolerance of a New Anti-Regurgitation Formula

  • Dupont, Christophe;Vandenplas, Yvan;SONAR Study Group
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.19 no.2
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    • pp.104-109
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    • 2016
  • Purpose: Regurgitation is a common physiological phenomenon in infants. The aim of the present study was to evaluate the efficacy of a new anti-regurgitation (AR) formula (Novalac), thickened with an innovative complex including fibres, on the daily number of regurgitations and to assess its impact on stool consistency and frequency. Methods: Infants younger than five months, presenting at least 5 regurgitations per day were recruited in this trial. The efficacy of the new formula on regurgitation (daily number and Vandenplas score), stool frequency and consistency were assessed at day 14 and 90. Growth data were recorded at each study visit. Results: Ninety babies (mean age $9.6{\pm}5.8weeks$) were included in the full analysis data set. The mean number of regurgitation episodes at inclusion was $7.3{\pm}3.4$. In all infants, regurgitations improved after 2 weeks. The daily number of regurgitations decreased significantly ($-6.3{\pm}3.3$, p<0.001) including in those previously fed a thickened formula ($-6.2{\pm}3.0$, p<0.001). There was no significant change in stool consistency at day 14. After 3 months, 97.5% of infants had formed or soft stools. Growth was appropriate with a slight increase of weight-for-age z-score (from $-0.5{\pm}1.0$ to $-0.1{\pm}0.9$) and no change of weight-for length z-score ($-0.1{\pm}1.1$ to $-0.1{\pm}-1.1$). Conclusion: The new AR formula thickened with an innovative complex is very effective in reducing the daily number of regurgitations without having a negative impact on stools consistency.

A Cephalometric Analysis on Esthetic Facial Soft Tissue of Korean Young Adult Female (한국인 젊은 여성의 심미적인 안면 연조직 형태에 관한 두부 X-선 계측학적 연구)

  • WOO, Je-Kyung;KWON, Oh-Won;SUNG, Jae-Hyun
    • The korean journal of orthodontics
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    • v.27 no.2
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    • pp.245-258
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    • 1997
  • Cephalometric radiographs, frontal photographs and profile silhouette phogographs of 68 young adult female who were model or were recommended to have esthetic face were used in this study. 7 Students in department of Art of Kyungpook national university and 15 orthodontists estimated profile slides which were made of 3 Profile silhouettes in parallel with FH plane. Profile silhouettes were made of soft tissue profile line of cephalometric radiograph. Only orthodontists estimated frontal photographs. Students and orthodontists score 9 in excellent case, score 7 in good case, score 5 in average case, score 3 in poor case. Correlation analysis between orthodontists' esthetic concept and Artists' esthetic concept, between frontal view esthetics and profile view esthetics which estimated by orthotontists, between profile view esthetics and profile measurements which consisted of measurements of 38 female who were scored above 5 mean score in profile silhouette by orthodontists were done. And the finding in this study indicated the following 1. Correlation between orthodontists' esthetic concept and Artists' esthetic concept in profile silhouette was significant (r=0.67,P=0.0001). 2. Correlation between frontal view esthetics and profile view esthetics which estimated by orthodontist was significant (r=0.26,P=0.0381). 3. Measurements which had significant correlation between profile measurements and profile view esthetics wer Na-Pog, to N', BNV to Pog', BNV/B' -Pog', Ls-Li-Pog', Li-B'-Pog' Z angle(P<0.05). 4 Mean and standard deviation of profile measurements of 38 female were obtained.

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Efficacy of Nutritional Therapy in Children with Crohn Disease (소아 크론병에서 영양 치료의 효과)

  • Suh, Hyun Ah;Kim, Sung Eun;Jang, Joo Young;Kim, Bong Jin;Kim, Joon Sung;Lee, Sun Youn;Chang, Soo Hee;Kim, Kyung Mo
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.9 no.2
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    • pp.210-217
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    • 2006
  • Purpose: Crohn disease (CD) in children is frequently complicated by malnutrition and growth retardation. Conventional treatment with corticosteroid may also affect the growth of children, which may be alleviated by nutritional therapy. Therefore, we performed this study to evaluate the role of nutritional therapy in the treatment of CD in children. Methods: The study cohort consisted of thirty children under the age of 17 years, admitted to the Asan Medical Center from 2001 to 2005. While 11 children received nutritional therapy (NT) with an elemental diet, 19 received conventional corticosteroid therapy (ST). Comparative analysis was performed for the rate of the induction of remission, recurrence, disease activity index of pre and post-treatment, and changes of the growth using mean standard deviation score for weight (zW) and height (zH). Results: Ten of 11 children with NT and 18 of 19 children with ST completed the therapy. Two of them were lost to follow-up during the treatment. All 10 children with NT and 15 of 18 children with ST achieved remission. While there was no recurrence in children with NT, 7 with ST showed recurrence within 1 year. Pre- and post treatment Pediatric Crohn disease Activity Index (PCDAI) did not show a difference between the two groups. There were no differences in zW and zH between the two groups after 1 year of follow-up. Conclusion: This study showed that nutritional therapy could be considered instead of steroid therapy for treatment of children with CD. However, a long-term study will be needed to determine the long-term efficacy.

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Prevalence and Associated Factors of Vertebral Fractures in Children with Chronic Liver Disease with and without Liver Transplantation

  • Wittayathorn Pornsiripratharn;Suporn Treepongkaruna;Phatthawit Tangkittithaworn;Niyata Chitrapaz;Chatmanee Lertudomphonwanit;Songpon Getsuwan;Pornthep Tanpowpong;Pat Mahachoklertwattana
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.27 no.3
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    • pp.158-167
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    • 2024
  • Purpose: To evaluate the prevalence of vertebral fracture (VF) in children with chronic liver disease (CLD) with and without liver transplantation (LT) and to determine the associated factors. Methods: A cross-sectional study was conducted. Patients aged 3-21 years with CLD both before and after LT were enrolled in the study. Lateral thoracolumbar spine radiographs were obtained and assessed for VF using Mäkitie's method. Clinical and biochemical data were collected. Results: We enrolled 147 patients (80 females; median age 8.8 years [interquartile range 6.0-11.8]; 110 [74.8%] in the LT group and 37 [25.2%] in the non-LT group). VF was identified in 21 patients (14.3%): 17/110 (15.5%) in the LT group and 4/37 (10.8%) in the non-LT group (p=0.54). Back pain was noted in only three patients with VF. In the univariate analysis, a height z-score below -2.0 (p=0.010), pre-LT hepatopulmonary syndrome (p=0.014), elevated serum direct and total bilirubin levels (p=0.037 and p=0.049, respectively), and vitamin D deficiency at 1-year post-LT (p=0.048) were associated with VF in the LT group. In multivariate analysis, height z-score below -2.0 was the only significant associated factor (odds ratio, 5.94; 95% confidence interval, 1.49-23.76; p=0.012) for VF. All VFs in the non-LT group were reported in males. Conclusion: In children with CLD, VF is common before and after LT. Most patients with VF are asymptomatic. Screening for VF should be considered in patients with a height z-score below -2.0 after LT.