• Title/Summary/Keyword: common method bias

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Classification of Premature Ventricular Contraction using Error Back-Propagation

  • Jeon, Eunkwang;Jung, Bong-Keun;Nam, Yunyoung;Lee, HwaMin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.2
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    • pp.988-1001
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    • 2018
  • Arrhythmia has recently emerged as one of the major causes of death in Koreans. Premature Ventricular Contraction (PVC) is the most common arrhythmia that can be found in clinical practice, and it may be a precursor to dangerous arrhythmias, such as paroxysmal insomnia, ventricular fibrillation, and coronary artery disease. Therefore, we need for a method that can detect an abnormal heart beat and diagnose arrhythmia early. We extracted the features corresponding to the QRS pattern from the subject's ECG signal and classify the premature ventricular contraction waveform using the features. We modified the weighting and bias values based on the error back-propagation algorithm through learning data. We classify the normal signal and the premature ventricular contraction signal through the modified weights and deflection values. MIT-BIH arrhythmia data sets were used for performance tests. We used RR interval, QS interval, QR amplitude and RS amplitude features. And the hidden layer with two nodes is composed of two layers to form a total three layers (input layer 0, output layer 3).

Effect of Psychological Empowerment on Turnover Intention through Job Satisfaction and Organizational Commitment: focus on Korea, China, Japan Employees

  • Kim, Boine
    • East Asian Journal of Business Economics (EAJBE)
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    • v.6 no.2
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    • pp.1-13
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    • 2018
  • Purpose - The present research is to investigate the effect of psychological empowerment on turnover intention through job satisfaction and organizational commitment. Research design, data, and methodology - These include turnover intention as dependent variable, psychological empowerment as an independent variable and for mediating variables job satisfaction and organizational commitment. Also nationality of employee is used as a moderating variable. Survey data was collected was total 886 respondents from 345 Korean, 313 Chinese, 228 Japanese. Data analysis was conducted with SPSS to test reliability of variables with Cronbach's alpha and one variable confirmatory factor analysis to test common method bias. And regression analysis was conducted to confirm relationship among variables. AMOS was used for path analysis and to analysis moderating effect of employees' country. Results - The results of regression indicate that psychological empowerment increase job satisfaction, affective commitment, normative commitment and turnover intention. Job satisfaction, affective commitment and normative commitment decrease turnover intention. As for the moderating role of country, it seems that country does matter. Conclusions - Main conclusions of this research implicate that to decrease employee turnover intention company need to manage psychological empowerment, job satisfaction, and organizational commitment. Also there is need to consider similarity and difference in managing employees of Korea, China and Japan employees. Manager need to verify direction and importance of each antecedent then apply to employees.

Simple power analysis in causal mediation models for a dichotomous outcome based on the mediation proportion

  • Kim, Young Min;Cologne, John Bennett;Cullings, Harry Michael
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.3
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    • pp.669-684
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    • 2017
  • Mediation models are widely used in many fields of research and have recently gained attention in epidemiology. The mediation proportion is a standard measure to evaluate what part of the total exposure effect on an outcome may be explained by a particular mediator and to examine how important that pathway is relative to the overall exposure effect. A common question is how large a sample size is needed to achieve high statistical power or, equivalently, what magnitude of effect can be detected. Current power and sample size calculations for mediation analysis are limited and additional research is needed. We therefore propose a computer-intensive power analysis using the mediation proportion. We conduct simulation studies to calculate statistical powers and sample sizes. And then, we illustrate our power analysis using an example from the Adult Health Study of atomic-bomb survivors and demonstrate that the method is relatively straightforward to understand and compute.

Evaluation of Amplified-based Target Preparation Strategies for Toxicogenomics Study : cDNA versus cRNA

  • Nam, Suk-Woo;Lee, Jung-Young
    • Molecular & Cellular Toxicology
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    • v.1 no.2
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    • pp.92-98
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    • 2005
  • DNA microarray analysis of gene expression in toxicogenomics typically requires relatively large amounts of total RNA. This limits the use of DNA microarray when the sample available is small. To confront this limitation, different methods of linear RNA amplification that generate antisense RNA (aRNA) have been optimized for microarray use. The target preparation strategy using amplified RNA in DNA microarray protocol can be divided into direct-incorporation labeling which resulted in cDNA targets (Cy-dye labeled cDNA from aRNA) and indirect-labeling which resulted in cRNA targets (i.e. Cy-dye labeled aRNA), respectively. However, despite the common use of amplified targets (cDNA or cRNA) from aRNAs, no systemic assessment for the use of amplified targets and bias in terms of hybridization performance has been reported. In this investigation, we have compared the hybridization performance of cRNA targets with cDNA targets from aRNA on a 10 K cDNA microarrays. Under optimized hybridization conditions, we found that 43% of outliers from cDNA technique and 86% from the outlier genes were reproducibly detected by both targets hybridization onto cDNA microarray. This suggests that the cRNA labeling method may have a reduced capacity for detecting the differential gene expression when compared to the cDNA target preparation. However, further validation of this discordant result should be pursued to determine which techniques possesses better accuracy in identifying truly differential genes.

Consideration of the analytical bias involved in the detection of total volatile organic compounds (TVOC) (총휘발성유기화합물 (TVOC) 검량의 오차인자에 대한 연구)

  • Kim, K.H.
    • Analytical Science and Technology
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    • v.17 no.6
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    • pp.489-495
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    • 2004
  • In this article, various aspects of errors involved in the measurement of TVOC were examined as part of study to develop the indoor pollution indices. For this purpose, TVOC term was computed by two different calibration approaches, i.e., by assuming all VOC are detected in the same manner as toluene and by summing up as many individual VOC as possible. The results of our study indicate that the common, toluene-based method suffers from errors inherent in the development of such theory. Consequently, it is concluded that more research efforts have to be directed to the improvement of such concept as TVOC.

Effectiveness of Education Interventions for the Management of Cancer Pain: A Systematic Review

  • Lee, Yoon Jae;Hyun, Min Kyung;Jung, Yea Ji;Kang, Min Joo;Keam, Bhumsuk;Go, Su Jin
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.12
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    • pp.4787-4793
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    • 2014
  • Background: Many cancer patients experience poor pain control due to various factors, including misconceptions regarding the use of opioid analgesics. For management of cancer pain, interventions involving education of both patients and physicians have been attempted. Objectives: This review aimed to assess the current evidence of the benefits of education for the management of cancer pain. Methods: We searched the Medline, EMBASE, Cochrane library, and major Korean databases to identify relevant studies. We included most study designs, but excluded case series. The primary outcomes were pain intensity and quality of life (QoL). Two reviewers assessed the risk of bias using the Cochrane's tool for RCT and Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) for non-randomized studies, independently. Results: After extensive searches, 3,324 publications were screened, and 32 studies were selected. The education interventions used in the included studies included a wide variety of education methods, but the most common method was a booklet produced for patients. Regardless of the education method used, the results of the meta-analysis were as follows. The SMDs of the most severe, average, and current pain in the RCTs were significant. The SMD of worst, average, and current pain were -0.34 (-0.55, -0.13), -0.40 (-0.64, -0.15), and -0.79 (-1.35, -0.23). In the non-randomized studies, the effects on average pain were significant, but those on worst and current pain were not. Conclusions: Education intervention reduced the pain of cancer patients. Therefore, patient education could be considered to be an effective method of cancer pain management. However, our data should be interpreted with caution, and studies using standardized protocols are needed to confirm these observations.

The Effects of Self-Congruity and Functional Congruity on e-WOM: The Moderating Role of Self-Construal in Tourism (중국 관광객의 온라인 구전에 대한 자아일치성과 기능일치성의 효과: 자기해석의 조절효과를 중심으로)

  • Yang, Qin;Lee, Young-Chan
    • The Journal of Information Systems
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    • v.25 no.1
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    • pp.1-23
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    • 2016
  • Purpose Self-congruity deals with the effect of symbolic value-expressive attributes on consumer decision and behavior, which is the theoretical foundation of the "non-utilitarian destination positioning". Functional congruity refers to utilitarian evaluation of a product or service by consumers. In addition, recent years, social network services, especially mobile social network services have created many opportunities for e-WOM communication that enables consumers to share personal consumption related information anywhere at any time. Moreover, self-construal is a hot and popular topic that has been discussed in the field of modem psychology as well as in marketing area. This study aims to examine the moderating effect of self-construal on the relationship between self-congruity, functional congruity and tourists' positive electronic word of mouth (e-WOM). Design/methodology/approach In order to verify the hypotheses, we developed a questionnaire with 32 survey items. We measured all the items on a five-point Likert-type scale. We used Sojump.com to collect questionnaire and gathered 218 responses from whom have visited Korea before. After a pilot test, we analyzed the main survey data by using SPSS 20.0 and AMOS 18.0, and employed structural equation modeling to test the hypotheses. We first estimated the measurement model for its overall fit, reliability and validity through a confirmatory factor analysis and used common method bias test to make sure that whether measures are affected by common-method variance. Then we tested the hypotheses through the structural model and used regression analysis to measure moderating effect of self-construal. Findings The results reveal that the effect of self-congruity on tourists' positive e-WOM is stronger for tourists with an independent self-construal compared with those with interdependent self-construal. Moreover, it shows that the effect of functional congruity on tourists' positive e-WOM becomes salient when tourists' self-construal is primed to be interdependent rather than independent. We expect that the results of this study can provide important implications for academic and practical perspective.

Analysis of Organic Molecular Markers in Atmospheric Fine Particulate Matter: Understanding the Impact of "Unknown" Point Sources on Chemical Mass Balance Models

  • Bae, Min-Suk;Schauer, James J.
    • Journal of Korean Society for Atmospheric Environment
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    • v.25 no.3
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    • pp.219-236
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    • 2009
  • Particle-phase organic tracers (molecular markers) have been shown to be an effective method to assess and quantify the impact of sources of carbonaceous aerosols. These molecular markers have been used in chemical mass balance (CMB) models to apportion primary sources of organic aerosols in regions where the major organic aerosol source categories have been identified. As in the case of all CMB models, all important sources of the tracer compounds must be included in a Molecular Marker CMB (MM-CMB) model or the MMCMB model can be subject to biases. To this end, the application of the MM-CMB models to locations where reasonably accurate emissions inventory of organic aerosols are not available, should be performed with extreme caution. Of great concern is the potential presence of industrial point sources that emit carbonaceous aerosols and have not been well characterized or inventoried. The current study demonstrates that emissions from industrial point sources in the St. Louis, Missouri area can greatly bias molecular marker CMB models if their emissions are not correctly addressed. At a sampling site in the greater St. Louis Area, carbonaceous aerosols from industrial point sources were found to be important source of carbonaceous aerosols during specific time periods in addition to common urban sources (i.e. mobile sources, wood burning, and road dust). Since source profiles for these industrial sources have not been properly characterized, method to identify time periods when point sources are impacting a sampling site, needs to avoid obtaining biases source apportionment results. The use of real time air pollution measurements, along with molecular marker measurements, as a screening tool to identify when point sources are impacting a receptor site is presented.

Construction Cost-Schedule Integration Management Methodolgy by using Progress Integration Unit (성과측정유닛을 활용한 건설 비용 - 일정 통합관리 방안)

  • Kang, Namhee;Choi, Jaehyun
    • Korean Journal of Construction Engineering and Management
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    • v.18 no.3
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    • pp.42-51
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    • 2017
  • Measuring and evaluating project progress and performance are the key element of the construction project success. Construction progress is typically measured quantitatively by evaluating cost and time allocated to the project deliverable, and thus properly integrating cost and time is essential to the project management. This research was performed to propose an alternative methodology to integrate the cost and time and provide a framework for the progress measurement. The researchers developed a typical work process for the cost and schedule planning and also developed an alternative cost-schedule integration method by using progress integration units (PIU). A discipline of a construction phase served as a common level for WBS and CBS integration, so the PIUs'were defined under discipline. A case study project was selected to validate the developed methodology. The result showed the proposed method improved efficiency of cost and time integration. The result also showed the excluding material for the progress measurement purpose significantly reduced the bias of progress measurement.

DTMOS Schmitt Trigger Logic Performance Validation Using Standard CMOS Process for EM Immunity Enhancement (범용 CMOS 공정을 사용한 DTMOS 슈미트 트리거 로직의 구현을 통한 EM Immunity 향상 검증)

  • Park, SangHyeok;Kim, SoYoung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.10
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    • pp.917-925
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    • 2016
  • Schmitt Trigger logic is a gate level design method to have hysteresis characteristics to improve noise immunity in digital circuits. Dynamic Threshold voltage MOS(DTMOS) Schmitt trigger circuits can improve noise immunity without adding additional transistors but by controlling substrate bias. The performance of DTMOS Schmitt trigger logic has not been verified yet in standard CMOS process through measurement. In this paper, DTMOS Schmitt trigger logic was implemented and verified using Magna $0.18{\mu}m$ MPW process. DTMOS Schmitt trigger buffer, inverter, NAND, NOR and simple digital logic circuits were made for our verification. Hysteresis characteristics, power consumption, and delay were measured and compared with common CMOS logic gates. EM Immunity enhancement was verified through Direct Power Injection(DPI) noise immunity test method. DTMOS Schmitt trigger logics fabricated using CMOS process showed a significantly improved EM Immunity in 10 M~1 GHz frequency range.