• Title/Summary/Keyword: Data Bias

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Evaluation of the Total Column Ozone in the Reanalysis Datasets over East Asia (동아시아 지역 오존 전량 재분석 자료의 검증)

  • Han, Bo-Reum;Oh, Jiyoung;Park, Sunmin;Son, Seok-Woo
    • Atmosphere
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    • v.29 no.5
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    • pp.659-669
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    • 2019
  • This study assesses the quality of the total column ozone (TCO) data from five reanalysis datasets against nine independent observation in East Asia. The assessed datasets are the ECMWF Interim reanalysis (ERAI), Monitoring Atmosphere Composition and Climate reanalysis (MACC), Copernicus Atmosphere Monitoring Service reanalysis (CAMS), the NASA Modern-Era Retrospective analysis for Research and Applications, Version2 (MERRA2), and NCEP Climate Forecast System Reanalysis (CFSR). All datasets reasonably well capture the spatial distribution, annual cycle and interannual variability of TCO in East Asia. In particular, characteristics of TCO according to the latitude difference were similar at all points with a maximum bias of less than about 4%. Among them, CAMS and CFSR show the smallest mean bias and root-mean square error across all nine ground-based observations. This result indicates that while TCO data in modern reanalyses are reasonably good, CAMS and CFSR TCO data are the best for analysing the spatio-temporal variability and change of TCO in East Asia.

A Missing Value Replacement Method for Agricultural Meteorological Data Using Bayesian Spatio-Temporal Model (농업기상 결측치 보정을 위한 통계적 시공간모형)

  • Park, Dain;Yoon, Sanghoo
    • Journal of Environmental Science International
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    • v.27 no.7
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    • pp.499-507
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    • 2018
  • Agricultural meteorological information is an important resource that affects farmers' income, food security, and agricultural conditions. Thus, such data are used in various fields that are responsible for planning, enforcing, and evaluating agricultural policies. The meteorological information obtained from automatic weather observation systems operated by rural development agencies contains missing values owing to temporary mechanical or communication deficiencies. It is known that missing values lead to reduction in the reliability and validity of the model. In this study, the hierarchical Bayesian spatio-temporal model suggests replacements for missing values because the meteorological information includes spatio-temporal correlation. The prior distribution is very important in the Bayesian approach. However, we found a problem where the spatial decay parameter was not converged through the trace plot. A suitable spatial decay parameter, estimated on the bias of root-mean-square error (RMSE), which was determined to be the difference between the predicted and observed values. The latitude, longitude, and altitude were considered as covariates. The estimated spatial decay parameters were 0.041 and 0.039, for the spatio-temporal model with latitude and longitude and for latitude, longitude, and altitude, respectively. The posterior distributions were stable after the spatial decay parameter was fixed. root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and bias were calculated for model validation. Finally, the missing values were generated using the independent Gaussian process model.

The Significant Roles of Corporate Counselors to Reduce Employee Stress for Enhancing their Performance

  • PARK, Joo-Young;KIM, Seong-Gon
    • The Journal of Industrial Distribution & Business
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    • v.13 no.8
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    • pp.1-7
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    • 2022
  • Purpose: The present study concentrates on the issues that affected the employees directly and acted as stress factors. These stress factors affect how the employees perform while undertaking their duties. Furthermore, this study evaluated how the involvement of the corporate counsel affected the company by enhancing the productivity of the employees. Research design, data and methodology: The research design of this research is a literature content analysis and method for data handling should be described, and the resultant combination of the studies should include the consistency measures for every meta-analysis. Specify any risk assessment of bias that may impact the cumulative evidence, such as the publication bias and the selective reporting within studies. Results: The finding shows that change in the location of employees' organizational restructuring and the introduction of new technologies also contributed to significant organizational stress factors. These results show a substantial correlation between the magnitude of the adjustments' effects on employees' performance. Conclusions: The current study strongly concludes that counselors, through their prowess, can analyze and evaluate the stress factors that are evident among the employees and in the organization. Some of these factors may be office layout, organizational codes of ethics, organization rules, and employees' personal challenges.

Historical changing of flow characteristics over Asian river basins

  • Ha, Doan Thi Thu;Kim, Tae-Son;Bae, Deg-Hyo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2020.06a
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    • pp.118-118
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    • 2020
  • This study investigates the change of flow characteristics over 10 Asian river basins in the past 30 years (1976-2005). The variation is estimated from The Soil and Water Assessment Tool (SWAT) model outputs based on reanalysis data which was bias-corrected for Asian monsoon reagion. The model was firstly calibrated and validated using observed data for daily streamflow. Four statistical criteria were applied to evaluate the model performance, including Coefficient of determination (R2), Nash - Sutcliffe model efficiency coeffi cient (NSE), Root mean square error-observations standard deviation ratio (RSR), and Percentage Bias (PBIAS). Then parameters of the model were applied for the historical period 1976-2005. The estimates show a temporal non-considerable increasing rate of daily streamflow in most of the basins over the past 30 years. The difference of monthly discharge becomes more significant during the months in the wet season (June to September) in all basins. The seasonal runoff shows significant difference in Summer and Autumn, when the rainfall intensity is higher. The line showing averaged runoff/rainfall ratio in all basins is sharp, presenting high variation of seasonal runoff/rainfall ratio from season to season.

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Influence of reciprocating and rotary instrumentation on microbial reduction: a systematic review and meta-analysis of in vitro studies

  • Selen Kucukkaya Eren;Emel Uzunoglu-Ozyurek;Sevilay Karahan
    • Restorative Dentistry and Endodontics
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    • v.46 no.2
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    • pp.19.1-19.12
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    • 2021
  • Objectives: The purpose of this study was to conduct a systematic review and meta-analysis of in vitro studies regarding the effectiveness of reciprocating and rotary instrumentation on microbial reduction in root canals. Materials and Methods: PubMed, Scopus, Web of Science, the Cochrane Library, and the gray literature were searched through December 2019. Studies comparing the influence of reciprocating and rotary instrumentation on the removal of microorganisms from root canals that quantified the antimicrobial effect were included. Data extraction was completed using a systematic form for data collection. The risk of bias of the studies was evaluated. Standardized mean differences (SMDs) and confidence intervals (CIs) were calculated using a random effects meta-analysis. Results: Seventeen in vitro studies were included in this systematic review, of which 7 provided adequate data for inclusion in the meta-analysis. Both reciprocating and rotary systems were similarly effective in reducing the microbial load in infected root canals (SMD [95% CI], 0.0481 [-0.271, 0.367]). Three studies showed a low risk of bias, whereas most of the studies (82%) presented a medium risk. Conclusions: Although both techniques decrease the microbial content (with reductions of 23.32%-88.47% and 23.33%-89.86% for reciprocating and rotary instrumentation, respectively), they are not able to provide complete disinfection of root canals.

Development of daily spatio-temporal downscaling model with conditional Copula based bias-correction of GloSea5 monthly ensemble forecasts (조건부 Copula 함수 기반의 월단위 GloSea5 앙상블 예측정보 편의보정 기법과 연계한 일단위 시공간적 상세화 모델 개발)

  • Kim, Yong-Tak;Kim, Min Ji;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
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    • v.54 no.12
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    • pp.1317-1328
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    • 2021
  • This study aims to provide a predictive model based on climate models for simulating continuous daily rainfall sequences by combining bias-correction and spatio-temporal downscaling approaches. For these purposes, this study proposes a combined modeling system by applying conditional Copula and Multisite Non-stationary Hidden Markov Model (MNHMM). The GloSea5 system releases the monthly rainfall prediction on the same day every week, however, there are noticeable differences in the updated prediction. It was confirmed that the monthly rainfall forecasts are effectively updated with the use of the Copula-based bias-correction approach. More specifically, the proposed bias-correction approach was validated for the period from 1991 to 2010 under the LOOCV scheme. Several rainfall statistics, such as rainfall amounts, consecutive rainfall frequency, consecutive zero rainfall frequency, and wet days, are well reproduced, which is expected to be highly effective as input data of the hydrological model. The difference in spatial coherence between the observed and simulated rainfall sequences over the entire weather stations was estimated in the range of -0.02~0.10, and the interdependence between rainfall stations in the watershed was effectively reproduced. Therefore, it is expected that the hydrological response of the watershed will be more realistically simulated when used as input data for the hydrological model.

Selection framework of representative general circulation models using the selected best bias correction method (최적 편이보정 기법의 선택을 통한 대표 전지구모형의 선정)

  • Song, Young Hoon;Chung, Eun-Sung;Sung, Jang Hyun
    • Journal of Korea Water Resources Association
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    • v.52 no.5
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    • pp.337-347
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    • 2019
  • This study proposes the framework to select the representative general circulation model (GCM) for climate change projection. The grid-based results of GCMs were transformed to all considered meteorological stations using inverse distance weighted (IDW) method and its results were compared to the observed precipitation. Six quantile mapping methods and random forest method were used to correct the bias between GCM's and the observation data. Thus, the empirical quantile which belongs to non-parameteric transformation method was selected as a best bias correction method by comparing the measures of performance indicators. Then, one of the multi-criteria decision techniques, TOPSIS (Technique for Order of Preference by Ideal Solution), was used to find the representative GCM using the performances of four GCMs after the bias correction using empirical quantile method. As a result, GISS-E2-R was the best and followed by MIROC5, CSIRO-Mk3-6-0, and CCSM4. Because these results are limited several GCMs, different results will be expected if more GCM data considered.

Relationship Between Sleep Quality and Depression Symptoms in Psychiatric Patients: Mediating Effect Interpretation Bias for Ambiguity and Anxiety Symptoms (정신건강의학과 환자의 수면의 질과 우울 증상의 관계: 모호함에 대한 해석 편향과 불안 증상의 매개효과)

  • Hyerin, Lee;Eunkyeong, Kim;Joonho, Choi;Seon-Cheol, Park
    • Korean Journal of Psychosomatic Medicine
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    • v.30 no.2
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    • pp.137-144
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    • 2022
  • Objectives : This study was designed to investigate the effect of sleep quality on depression symptoms and the mediating effect of interpretation bias and anxiety symptoms in psychiatric patients. Methods : Data accumulated for outpatients and inpatients in the Department of Mental Health Medicine at Hanyang University Guri Hospital were used. The measurement tools were Pittsburgh Sleep Quality Index (PSQI), Ambiguous/Unambiguous Situations Diary-Extended Version (AUSD-EX), Beck Anxiety Inventory (BAI), Beck Depression Inventory-II (BDI-II). Correlation analysis and bootstrapping analysis were conducted using SPSS 25.0 and SPSS Macro based on 162 patient data. Results : As a result of the study, the double mediating effect of interpretation bias for Ambiguity and anxiety symptoms was significant in the relationship between sleep quality and depression symptoms. Conclusions : In this study, it was confirmed that low sleep quality sequentially affects anxiety and depression symptoms through interpretation bias for ambiguity. Based on this, it is expected that the development of other psychiatric symptoms can be prevented by preferentially performing therapeutic intervention on preceding symptoms.

The Relationship between Rejection Sensitivity and Reactive Aggression in University Students: Mediating Effects of Self-Concept Clarity and Hostile Attribution Bias (대학생의 거부민감성과 반응적 공격성 간의 관계: 자기개념 명확성과 적대적 귀인편향의 매개효과)

  • Geonhee Lee ;Minkyu Rhee
    • Korean Journal of Culture and Social Issue
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    • v.29 no.4
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    • pp.477-496
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    • 2023
  • The purpose of this study is to examine the relationship between rejection sensitivity and reactive aggression among college students, as well as to determine the mediating effects of self-concept clarity and hostile attribution bias on the relationship between rejection sensitivity and reactive aggression. A self-report questionnaire was conducted online for the purpose of gathering data from university students aged 18 years and older. A total of 250 participants were included in the analysis. SPSS 27.0 was used for data analysis to check the basic statistics of the variables, frequency analysis, reliability analysis, and correlation analysis. In addition, the model fit was checked using Amos 21.0, and the bootstrapping method verified the significance of the indirect effect. The results of this study are as follows. The results of this study are as follows. First, rejection sensitivity positively affects reactive aggression through self-concept clarity. Second, rejection sensitivity increases the hostile attribution bias, leading to an increase in reactive aggression. Third, rejection sensitivity positively influences reactive aggression in an indirect way by sequentially affecting self-concept clarity and hostile attribution bias. These findings have implications as they identify psychological factors that affect reactive aggression in college students. This suggests the importance of utilizing psychological interventions to address reactive aggression associated with social problems, such as crime, and provides a foundation for both treatment and prevention. Finally, implications for further research and limitations of this study are suggested.

Factors Influencing the Investor's Decision Making: The Moderating Role of Locus of Control

  • KAMRAN, Hafiz Waqas;QAISAR, Abthal;SULTANA, Nayyer;NAWAZ, Muhammad Atif;AHMAD, Hafiz Tanveer
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.535-543
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    • 2020
  • Investors from the whole world are looking for those stock markets that are less affected by interest rates. Pakistan is a good place to invest and the investors from the whole world are considering Pakistan for future ventures. The current study, therefore, aims to analyze the factors affecting investors' decision making in Pakistan with the interaction effect of locus of control. The primary data are gathered from 300 respondents. Structural equation modelling (SEM-PLS) is used to analyze the interactions among variables. The study finds positive impact of availability and representative biases on investment decision making. The study could not find any moderating role of locus of control. The results imply that decisions made by Pakistani investors are driven by the most easily or currently available information and they trust on the information obtained from family and friends without any authentication and verification. One possible description of insignificant moderation effect of locus of control can be the sample traits used in the study, e.g., personal characteristics, that change from culture to culture. Another description of these findings may be the association between heuristic biases, including availability, representative and psychological biases and decision-making regarding investment is not personality specific.