• 제목/요약/키워드: Selection-bias

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A Study on Selecting Principle Component Variables Using Adaptive Correlation (적응적 상관도를 이용한 주성분 변수 선정에 관한 연구)

  • Ko, Myung-Sook
    • KIPS Transactions on Software and Data Engineering
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    • v.10 no.3
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    • pp.79-84
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    • 2021
  • A feature extraction method capable of reflecting features well while mainaining the properties of data is required in order to process high-dimensional data. The principal component analysis method that converts high-level data into low-dimensional data and express high-dimensional data with fewer variables than the original data is a representative method for feature extraction of data. In this study, we propose a principal component analysis method based on adaptive correlation when selecting principal component variables in principal component analysis for data feature extraction when the data is high-dimensional. The proposed method analyzes the principal components of the data by adaptively reflecting the correlation based on the correlation between the input data. I want to exclude them from the candidate list. It is intended to analyze the principal component hierarchy by the eigen-vector coefficient value, to prevent the selection of the principal component with a low hierarchy, and to minimize the occurrence of data duplication inducing data bias through correlation analysis. Through this, we propose a method of selecting a well-presented principal component variable that represents the characteristics of actual data by reducing the influence of data bias when selecting the principal component variable.

A Systematic Review on the Treatment of Post-Stroke Patients Based on Sasang Constitutional Medicine (사상의학적 중풍 후유증 치료에 대한 체계적 문헌 고찰)

  • Oh, Hyunjoo;Lee, Jeongyun;Lee, Hyeri;Lee, Junhee
    • Journal of Sasang Constitutional Medicine
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    • v.34 no.2
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    • pp.48-64
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    • 2022
  • Objectives The purpose of this study was to review and evaluate the clinical evidence of the efficacy and safety of treatment based on Sasang constitutional medicine (SCM) for post-stroke patients by systematic review and meta-analysis. Methods Randomized controlled trials (RCTs), published in 10 electronic databases up to December 2020, were searched. For the included studies, Cochrane's risk of bias assessment was performed to analyze the methodological quality. The strength of evidence was evaluated using the grading of recommendations assessment, development, and evaluation system based on the results of analyses. All review processes were performed by two independent researchers. Results Five RCTs were finally included. All included RCTs were conducted for one month on post-stroke patients in 60-80s, four studies on Tae-Eum patients and one study on So-Yang patients. Four types of constitution-specific herbal medicine (Chungpyesagan-tang, Cheongsimsanyak-tang, Yeoldahanso-tang, and Yangkyuksanhwa-tang) and constitution-specific acupuncture therapy were identified as interventions. More than half of the included studies were evaluated as low quality due to the high-risk of bias in selection, performance, and detection. The combination of constitution-specific herbal medicine, acupuncture, and conventional treatment was more effective in improving the patients' motor impairment, dysphagia, aphasia, and depression than conventional treatment alone. No serious adverse events by SCM treatment were reported. Conclusions SCM treatment may improve the sequelae of post-stroke patients safely in combination with conventional treatment. Since the quality of clinical evidence included in this study was low, higher quality clinical evidence obtained in well-designed clinical studies will be needed.

The effects of maternal-child nursing clinical practicum using virtual reality on nursing students' competencies: a systematic review (가상현실을 이용한 모아간호 실습교육이 간호 대학생의 실습역량에 미치는 영향: 체계적 문헌고찰)

  • Hwang, Sungwoo;Kim, Hyun Kyoung
    • Women's Health Nursing
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    • v.28 no.3
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    • pp.174-186
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    • 2022
  • Purpose: This study aimed to investigate the effects of virtual reality used in maternal-child nursing clinical practicums on nursing students' competencies through a systematic review. Methods: The inclusion criteria were peer-reviewed papers in English or Korean presenting analytic studies of maternal-child nursing practicums using virtual reality. An electronic literature search of the Cochrane Library, CINAHL, EMBASE, ERIC, PubMed, and Research Information Sharing System databases was performed using combinations of the keywords "nursing student," "virtual reality," "augmented reality," "mixed reality," and "virtual simulation" from February 4 to 15, 2022. Quality appraisal was performed using the RoB 2 and ROBINS-I tools for randomized controlled trials (RCTs) and non-RCTs, respectively. Results: Of the seven articles identified, the RCT study (n=1) was deemed to have a high risk of bias, with some items indeterminable due to a lack of reported details. Most of the non-RCT studies (n=6) had a moderate or serious risk of bias related to selection and measurement issues. Clinical education using virtual reality had positive effects on knowledge, skills, satisfaction, self-efficacy, and needs improvement; however, it did not affect critical thinking or self-directed learning. Conclusion: This study demonstrated that using virtual reality for maternal-child nursing clinical practicums had educational effects on a variety of students' competencies. Considering the challenges of providing direct care in clinical practicums, virtual reality can be a viable tool that supplements maternal-child nursing experience. Greater rigor and fuller reporting of study details are required for future research.

Complications reported with the use of orthodontic miniscrews: A systematic review

  • Giudice, Antonino Lo;Rustico, Lorenzo;Longo, Miriam;Oteri, Giacomo;Papadopoulos, Moschos A.;Nucera, Riccardo
    • The korean journal of orthodontics
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    • v.51 no.3
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    • pp.199-216
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    • 2021
  • Objective: The aim of this systematic review was to evaluate the complications and side effects associated with the clinical use of orthodontic miniscrews by systematically reviewing the best available evidence. Methods: A survey of articles published up to March 2020 investigating the complications associated with miniscrew insertion, in both the maxilla and mandible, was performed using 7 electronic databases. Clinical studies, case reports, and case series reporting complications associated with the use of orthodontic miniscrew implants were included. Two authors independently performed study selection, data extraction, and risk-of-bias assessment. Results: The database survey yielded 24 articles. The risk-of-bias assessment revealed low methodological quality for the included studies. The most frequent adverse event reported was root injury with an associated periradicular lesion, vitality loss, pink discoloration of the tooth, and transitory loss of pulp sensitivity. Chronic inflammation of the soft tissue surrounding the miniscrew with mucosal overgrowth was also reported. The other adverse events reported were lesion of the buccal mucosa at the insertion site, soft-tissue necrosis, and perforation of the floor of the nasal cavity and maxillary sinus. Adverse events were also reported after miniscrew removal and included secondary bleeding, miniscrew fracture, scars, and exostosis. Conclusions: These findings highlight the need for clinicians to preliminarily assess generic and specific insertion site complications and side effects.

Anesthetic efficacy in vital asymptomatic teeth using different local anesthetics: a systematic review with network meta-analysis

  • Amy Kia Cheen Liew;Yi-Chun Yeh ;Dalia Abdullah ;Yu-Kang Tu
    • Restorative Dentistry and Endodontics
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    • v.46 no.3
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    • pp.41.1-41.23
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    • 2021
  • Objectives: This study aimed to evaluate the efficacy of various local anesthesia (LA) in vital asymptomatic teeth. Materials and Methods: Randomized controlled trials comparing pulpal anesthesia of various LA on vital asymptomatic teeth were included in this review. Searches were conducted in the Cochrane CENTRAL, MEDLINE (via PubMed), EMBASE, ClinicalTrials.gov, Google Scholar and 3 field-specific journals from inception to May 3, 2019. Study selection, data extraction, and risk of bias assessment using Cochrane Risk of Bias Tool were done by 2 independent reviewers in duplicate. Network meta-analysis (NMA) was performed within the frequentist setting using STATA 15.0. The LA was ranked, and the surface under the cumulative ranking (SUCRA) line was plotted. The confidence of the NMA estimates was assessed using the CINeMA web application. Results: The literature search yielded 1,678 potentially eligible reports, but only 42 were included in this review. For maxillary buccal infiltration, articaine 4% with epinephrine 1:100,000 was more efficacious than lidocaine 2% with epinephrine 1:100,000 (odds ratio, 2.11; 95% confidence interval, 1.14-3.89). For mandibular buccal infiltration, articaine 4% with epinephrine 1:100,000 was more efficacious than various lidocaine solutions. The SUCRA ranking was highest for articaine 4% with epinephrine when used as maxillary and mandibular buccal infiltrations, and lidocaine 2% with epinephrine 1:80,000 when used as inferior alveolar nerve block. Inconsistency and imprecision were detected in some of the NMA estimates. Conclusions: Articaine 4% with epinephrine is superior when maxillary or mandibular infiltration is required in vital asymptomatic teeth.

Reference values for pulp oxygen saturation as a diagnostic tool in endodontics: a systematic review and meta-analysis

  • Paula Lambert;Sergio Augusto Quevedo Miguens Jr;Caroline Solda;Juliana Tomaz Sganzerla;Leandro Azambuja Reichert;Carlos Estrela;Fernando Branco Barletta
    • Restorative Dentistry and Endodontics
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    • v.45 no.4
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    • pp.48.1-48.11
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    • 2020
  • Objectives: This systematic review aimed to identify mean oxygen saturation values (SpO2) using pulse oximetry in permanent maxillary anterior teeth. Materials and Methods: The MEDLINE, Scientific Electronic Library Online, Cochrane Central Register of Controlled Trials, EMBASE, and Literatura Latino Americana em Ciências da Saúde electronic databases were searched. Combinations and variations of "oximetry" AND "dental pulp test" were used as search terms. Studies reporting means and standard deviations of SpO2 values were included. Two reviewers independently extracted data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Heterogeneity was assessed using the I2 statistic, and all analyses were performed using R software. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale. Results: Of the 251 studies identified, 19 met the eligibility criteria and were included (total sample, 4,541 teeth). In the meta-analysis, the mean SpO2 values were 84.94% (95% confidence interval [CI], 84.85%-85.04%) for the central incisors, 89.29% (95% CI, 89.22%-89.35%) for the lateral incisors, and 89.20% (95% CI, 89.05%-89.34%) for the canines. The studies were predominantly low-quality due to the high risk of bias associated with the index test, unclear risk regarding patient selection, and concerns about outcome assessment. Conclusions: Although most studies were low-quality, the oxygen saturation levels in normal pulp could be established (minimum saturation, 77.52%). Despite the risk of bias of the included studies, the reference values reported herein are clinically relevant for assessments of changes in pulp status.

Analyzing the Impact of Emission Control Area (ECA) Enforcement on Ferry Companies' Financial Performance : Network SBM DEA and BTR model (배출규제해역(ECA) 시행이 페리 선사의 재무성과에 미치는 영향: Network SBM DEA 및 BTR 모형 분석)

  • Lee, Suhyung;Lim, Hyunwoo
    • Journal of Korea Port Economic Association
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    • v.38 no.3
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    • pp.29-51
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    • 2022
  • The International Maritime Organization (IMO) designated the Emission Control Area (ECA) in Northern Europe to reduce the NOx and SOx emissions from ships in the coastal areas. This study used Network slack-based measure (SBM) Data Envelopment Model (DEM) and Bootstrop Truncated Regression (BTR) model to analyze the ECA's impact on ferry companies' financial performances based on the financial data from eight ferry carriers in Northern Europe, the Mediterranean and North America from 2004 to 2017. To alleviate the problem of arbitrary variable selection in DEA, the variable selection criteria proposed by Dyson et al. (2001) were applied; the size of the company was considered through the Network SBM DEA model; and the company's profit-generating process was divided into stages to measure financial performance in more detail. In addition, the BTR model was applied to derive results that minimize the bias of the data. The study found that ECA regulations did not always negatively affect the shipping companies' financial performance. Rather, a steady increase in efficiency was observed for Northern European ferry companies which were subject to the strongest regulations. For North American ferry companies, government subsidies were found to have a significant impact on efficiency, and relatively small impact on efficiency due to the ECA and oil prices. For the Mediterranean ferry companies, efficiency values have decreased since the implementation of ECA regulation despite the lowest level of regulation in the region.

High resolution flexible e-paper driven by printed OTFT

  • Hu, Tarng-Shiang;Wang, Yi-Kai;Peng, Yu-Rung;Yang, Tsung-Hua;Chiang, Ko-Yu;Lo, Po-Yuan;Chang, Chih-Hao;Hsu, Hsin-Yun;Chou, Chun-Cheng;Hsieh, Yen-Min;Liu, Chueh-Wen;Hu, Jupiter
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.421-427
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    • 2009
  • We successfully fabricated 4.7-inch organic thin film transistors array with $640{\times}480$ pixels on flexible substrate. All the processes were done by photolithography, spin coating and ink-jet printing. The OTFT-Electrophoretic (EP) pixel structure, based on a top gate OTFT, was fabricated. The mobility, ON/OFF ratio, subthreshold swing and threshold voltage of OTFT on flexible substrate are: 0.01 ^2/V-s, 1.3 V/dec, 10E5 and -3.5 V. After laminated the EP media on OTFT array, a panel of 4.7-inch $640{\times}480$ OTFT-EPD was fabricated. All of process temperature in OTFT-EPD is lower than $150^{\circ}C$. The pixel size in our panel is $150{\mu}m{\times}150{\mu}m$, and the aperture ratio is 50 %. The OTFT channel length and width is 20 um and 200um, respectively. We also used OTFT to drive EP media successfully. The operation voltages that are used on the gate bias are -30 V during the row data selection and the gate bias are 0 V during the row data hold time. The data voltages that are used on the source bias are -20 V, 0 V, and 20 V during display media operation.

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Herbal Medicine for Liver Cancer: A Protocol for Systematic Review and Meta-Analysis (간암에 대한 한약치료: 체계적 문헌고찰 및 메타분석의 프로토콜)

  • Kwon, Seungwon;Song, Ga Yeon;Yang, Seung-Bo
    • The Journal of Internal Korean Medicine
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    • v.43 no.4
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    • pp.559-566
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    • 2022
  • Introduction: The aim of this systematic review is to provide evidence confirming the efficacy and safety of herbal medicines used in the treatment of liver cancer. Methods: The review will include randomized clinical trials that compared herbal medicines used as treatments for liver cancer with other therapies, such as placebos and Western medicine. Only randomized controlled trials will be included in this review, and all types of herbal medicine will be evaluated. Eleven electronic databases will be searched from the inception date: the Cochrane Database of Systematic Reviews, MEDLINE, EMBASE, AMED, CINAHL, one Chinese database (CNKI), and five Korean databases (OASIS, DBpia, RISS, KISS, and NDSL). The selection of studies, data extraction, and management will be performed independently by four researchers. Methodological quality, including the risk of bias, will be assessed using the Cochrane risk-of-bias assessment tool. Results: The review of current evidence for the effectiveness of herbal medicine for liver cancer will be summarized and quantitatively analyzed. Conclusions: Our systematic review will provide evidence of the efficacy of herbal medicines as treatments for liver cancer. This evidence will provide useful information for practitioners and patients in the fields of oncology and complementary medicine.

Effects of Laughter Therapy on Depression and Sleep Wake Disorders of the Elderly in Residential Facilities : A Systematic Review and Meta-analysis (웃음요법이 시설거주 노인의 우울과 수면 장애에 미치는 효과 : 체계적 고찰 및 메타분석)

  • Kim, Eun-Jung;Yang, Jin-Hyang
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.8
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    • pp.291-303
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    • 2021
  • The purpose of this study is to identify the effects of laughter therapy on depression and sleep wake disorders among the elderly in residential facilities using a systemic review and meta-analysis. Twelve databases were searched. Two researchers independently performed the selection of the studies, data coding and assessment. The risk of bias was assessed using risk of bias (RoB) and risk of bias assessment tool for non-randomized studies (RoBANs). To estimate the effect size, meta-analysis of the studies was performed using R version 4.04. Out of the 1,122 retrieved articles, one randomized controlled trial (RCT) and eleven non-randomized controlled trials (non-RCTs) were selected for analysis. The overall effect size of eleven studies on depression was determined to be -1.04 (95% Cl: -1.53~-0.54, p<.001). There were statistically significant in the effect of below ten sessions and the effect of below 400 minutes'and 400 to 1000 minutes'interventions on depression. The overall effect size of five studies on sleep wake disorders was 0.83 (95% Cl: -0.26~1.93, p=.136), which was not statistically significant. There was statistically significant in the effect of below 300 minutes'interventions on sleep wake disorders. Laughter therapy was an effective non-pharmacological intervention to reduce depression among the elderly in residential facilities. The findings also suggest that guidelines for laughter therapy need to be developed considering the number of sessions and a duration of intervention to reduce depression and sleep wake disorders of the elderly in residential facilities.