• Title/Summary/Keyword: Statistical Methodology

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A Study on Quantitative Evaluation Method for Risk of Work-related Musculoskeletal Disorders Associated with Back Flexion Posture (작업관련성 근골격계질환에 있어서 작업자세 위험도의 정량적 평가방법에 대한 연구 -허리 굴곡 자세를 중심으로-)

  • Park, Dong Hyun;Noh, An Na;Choi, Seo Yeon
    • Journal of the Korea Safety Management & Science
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    • v.16 no.1
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    • pp.119-127
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    • 2014
  • This study tried to develop a basis for quantitative index of working postures associated with WMSDs (Work-related Musculoskeletal Disorders) that could overcome realistic restriction during application of typical checklists for WMSDs evaluation. The baseline data(for a total of 603 jbs) for this study was obtained from automobile manufacturing company. Specifically, data for back posture was analyzed in this study to have a better and more objective method in terms of job relevance than typical methods such as OWAS, RULA, and REBA. Major statistical tools were clustering, logistic regression and so on. The main results in this study could be summarized as follows; 1) The relationship between working posture and WMSDs symptom at back was statistically significant based on the results from logistic regression, 2) Based on clustering analysis, three levels for WMSDs risk at back were produced for flexion as follows: low risk(< $18.5^{\circ}$), medium risk($18.5^{\circ}{\sim}36.0^{\circ}$), high risk(> $36.0^{\circ}$), 3) The sensitivities on risk levels of back flexion was 93.8% while the specificities on risk levels of back flexion was 99.1%. The results showed that the data associated with back postures in this study could provide a good basis for job evaluation of WMSDs at back. Specifically, this evaluation methodology was different from the methods usually used at WMSDs study since it tried to be based on direct job relevance from real working situation. Further evaluation for other body parts as well as back would provide more stability and reliability in WMSDs evaluation study.

Research on Application of Service Design Methodology in IOT Environment

  • Kim, Byung-Taek;Cho, Yun-Sung
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.3
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    • pp.53-60
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    • 2017
  • The purpose of this study is to provide empirical and quantitative analysis on user's perceived privacy, security, and user satisfaction when providing visualization information about objects and service provider behaviors that users can not perceive in internet service process. Through previous research, we have examined the importance of privacy and security factors as a key factor to be considered for the characteristics of the Internet of things and the Internet of things. In addition, service blueprint, which is one of the service design methodologies to examine the flow of service usage in providing Internet service of things, was examined. In the flow of things internet service utilization, it is found that the things that are out of the user's cognitive area and the behavior of the service provider take up a large part. Therefore, the hypothesis that the trust of the Internet service security and the satisfaction of the user experience can be improved by providing the security visualization information about the behavior of the object and the invisible service provider in the non-contact aspect of the user and the object. In order to verify the hypothesis, we conducted experiments and questionnaires on the use of virtual objects' internet environment and conducted statistical analysis based on them. As a result, it was analyzed that visual information feedback on non - contact and invisible objects and service provider's behaviors had a positive effect on user's perceived privacy, security, and satisfaction. In addition, we conclude that it can be used as a service design evaluation tool to eliminate psychological anxiety about security and to improve satisfaction in internet service design. We hope that this research will be a great help for the research on application method of service design method in Internet environment of objects.

Plant breeding in the 21st century: Molecular breeding and high throughput phenotyping

  • Sorrells, Mark E.
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.14-14
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    • 2017
  • The discipline of plant breeding is experiencing a renaissance impacting crop improvement as a result of new technologies, however fundamental questions remain for predicting the phenotype and how the environment and genetics shape it. Inexpensive DNA sequencing, genotyping, new statistical methods, high throughput phenotyping and gene-editing are revolutionizing breeding methods and strategies for improving both quantitative and qualitative traits. Genomic selection (GS) models use genome-wide markers to predict performance for both phenotyped and non-phenotyped individuals. Aerial and ground imaging systems generate data on correlated traits such as canopy temperature and normalized difference vegetative index that can be combined with genotypes in multivariate models to further increase prediction accuracy and reduce the cost of advanced trials with limited replication in time and space. Design of a GS training population is crucial to the accuracy of prediction models and can be affected by many factors including population structure and composition. Prediction models can incorporate performance over multiple environments and assess GxE effects to identify a highly predictive subset of environments. We have developed a methodology for analyzing unbalanced datasets using genome-wide marker effects to group environments and identify outlier environments. Environmental covariates can be identified using a crop model and used in a GS model to predict GxE in unobserved environments and to predict performance in climate change scenarios. These new tools and knowledge challenge the plant breeder to ask the right questions and choose the tools that are appropriate for their crop and target traits. Contemporary plant breeding requires teams of people with expertise in genetics, phenotyping and statistics to improve efficiency and increase prediction accuracy in terms of genotypes, experimental design and environment sampling.

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Evaluation of Trophic State of a Small-scale Pond (Wonheung) in Ecological Park (소규모 생태연못(원흥이 방죽)의 부영양화 평가)

  • Lee, Heung Soo;Chung, Se Woong;Choi, Jung Kyu;Shin, Sang Il
    • Journal of Korean Society on Water Environment
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    • v.24 no.6
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    • pp.741-749
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    • 2008
  • Many small-scale ponds that serve as ecological habitat, recreation and irrigation are faced to eutrophication problem, which causes aesthetic nuisance and ultimately loss of their functions. Thus accurate evaluation of the trophic state of these ponds is essential to provide rational information to the stakeholders so that they can develop effective management actions. In this study, the trophic state of a small pond (Wonheung) that experiencing water quality degradation due to vicinity land development was assessed using various Trophic State Indexes (TSIs) and statistical analysis including Principal Components Analysis (PCA) based on the field monitoring data obtained from May to December, 2007. The results showed that the pond is under eutrophic state with average total nitrogen (T-N) and total phosphorus (T-P) concentrations of $708.1{\mu}g/L$ and $59.3{\mu}g/L$, respectively. The factor loading plot obtained from PCA showed distinct two influencing factors, PC 1 and PC 2. PC 1 was grouped by T-P, Chlorophyll a (Chl-a), suspended solids (SS), TN/TP ratio, and transparency that all strongly related to the eutrophication state, while PC 2 by temperature, conductivity, dissolved oxygen (DO) and turbidity that explains the seasonal water quality variations. The limiting factor was identified as light rather than phosphorus by both T-N/T-P ratio and TSI indexes analysis. The results and methodology adopted in this study can be used for water quality assessment for other small ponds and lakes.

Noise reduction by sigma filter applying orientations of feature in image (영상에 포함된 특징의 방향성을 적용한 시그마 필터의 잡음제거)

  • Kim, Yeong-Hwa;Park, Youngho
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.6
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    • pp.1127-1139
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    • 2013
  • In the realization of obtained image by various visual equipments, the addition of noise to the original image is a common phenomenon and the occurrence of the noise is practically impossible to prevent completely. Thus, the noise detection and reduction is an important foundational purpose. In this study, we detect the orientation about feature of images and estimate the level of noise variance based on the measurement of the relative proportion of the noise. Also, we apply the estimated level of noise to the sigma filter on noise reduction algorithm. And using the orientation about feature of images by weighted value, we propose the effective algorithm to eliminate noise. As a result, the proposed statistical noise reduction methodology provides significantly improved results over the usual sigma filtering and regardless of the estimated level of the noise variance.

Characteristic of PM10 Distribution Related to Precise Local Wind Patterns in Busan Metropolitan Area (상세 국지 기류 분포를 고려한 부산 지역 내 미세 먼지 분포 특성)

  • Hong, Seon-Hwa;Lee, Soon-Hwan
    • Journal of Environmental Science International
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    • v.26 no.12
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    • pp.1375-1387
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    • 2017
  • In order to investigate the $PM_{10}$ concentration trend and its characteristics over five different sub area in Busan from 2013 to 2015, data analysis with considering air flow distribution according to its topography was carried out using statistical methodology. The annual mean concentrations of $PM_{10}$ in Busan tend to decrease from $49.6{\mu}g/m^3$ in 2013 to $46.9{\mu}g/m^3$ in 2015. The monthly mean concentrations value of $PM_{10}$ were high during spring season, from March to May, and low during summer and fall due to frequent rain events. The concentration of $PM_{10}$ was the highest in five different sub-area in Busan. High concentration episodes over 90 percentile of daily $PM_{10}$ concentration were strongly associated with mean daily wind speed, and often occurred when the westerly wind or southwesterly wind were dominant. Regardless of wind direction, the highest correlation of $PM_{10}$ concentrations was observed between eastern and southern regions, which were geographically close to each other, and the lowest in the western and eastern regions blocked by mountains. Wind flow along the complex terrain in Busan is also one of the predominant factors to understand the temporal variation of $PM_{10}$ concentrations.

A Study on New Gameplay Experience Based on Brain-Computer Interface (BCI를 기반으로 하는 플레이어의 새로운 게임플레이 경험 연구)

  • Ko, Min-Jin;Oh, Gyu-Hwan;Bae, Kyoung-Woo
    • Journal of Korea Game Society
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    • v.9 no.6
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    • pp.31-44
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    • 2009
  • BCI (Brain-Computer Interface) is a way to control computer by using the human brain waves. As the hardware using brain wave technologies has developed, former expensive and big sized brain wave measuring devices have recently become much smaller and cheaper in their prices, making it possible for the individuals to buy them. This predicts them to be applied in various fields of multimedia industry. This thesis is to give an insight into whether the BCI device can be used as a new gaming device approaching it in a game designing point of view. At first, we proposed game play elements that can effectively utilizing the BCI devices, systematize, and produced a game prototype adopting the BCI device based on such game play elements. Next, we verified it with statistical data analysis to show that the prototype adopting the BCI device gives more clear and efficient controls in its game play than a game of only adopting keyboard & mouse devices and analysis verified that BCI-based game play elements provide users with a more intuitive and interesting experience than traditional non-BcI-based game play elements. The results will give a guideline for effective game design methodology for making BCI based games.

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Chuna Manual Therapy for Stroke: A Systematic Review and Meta-analysis (뇌졸중의 추나요법에 대한 체계적 문헌 고찰)

  • Kim, Mi-Kyung;Han, Chang-Ho
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.14 no.2
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    • pp.15-28
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    • 2019
  • Objectives : This study aimed to systematically and comprehensively review controlled clinical trials on the effectiveness and safety of Chuna Manual Therapy for stroke. Methods : By October 7, 2019, three core databases and three domestic databases were searched. Seven major academic journals on the related field were also hand-searched. Methodological quality of the included studies was evaluated using the Cochrane risk of bias tool. Meta-analysis was conducted and the quality of its evidence was assessed using the GRADE methodology. Results : Five articles met the eligibility criteria. The results of most of included studies were in favor of Chuna Manual Therapy. No study described any adverse events during or after the clinical trials. Meta-analysis of three eligible studies showed that the pre- and post-treatment scores on the Modified Barthel Index (mean difference 8.00, 95% confidence interval 0.26 to 15.74) and Berg Balance Scale (mean difference 3.57, 95% confidence interval 0.64 to 6.51) of the Chuna-treated group were significantly different, but only marginally higher than those of the non-treatment group. Thus, the level of evidence gathered from these studies was assessed to be low. Conclusions : Based on current available evidence, any confirmative conclusions cannot be made on the effectiveness and safety of Chuna Manual Therapy for stroke because of the small sample size, low methodological quality, presence of statistical heterogeneity, and missing safety information. More rigorously designed large-scale multi-center studies are needed to establish more specific and credible evidence to support or oppose the use of Chuna Manual Therapy for stroke.

The Interactive Effects of Motivation and Contingent Rewards on Employee Creativity (조직구성원의 외재적, 내재적 동기와 창의성의 관계: 조건적 보상의 조절효과)

  • Hwang, Soyeon;Jung, Heajung
    • The Journal of Industrial Distribution & Business
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    • v.9 no.7
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    • pp.71-82
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    • 2018
  • Purpose - This study examined the effects of intrinsic and extrinsic motivation on employee creativity. Past research has consistently shown that intrinsic motivation is positively related to creativity. Yet conflicting results have been reported about the relationship between extrinsic motivation and creativity. To explore the reason why extrinsic motivation can either help or hurt creativity, we examined the role of contingent rewards as a moderator and tested whether either tangible or intangible rewards contingent upon creative performance significantly impact the relationship between extrinsic motivation and creativity. Research design, data, and methodology - Survey data was collected from employees working for diverse organizations in Korea through online research firm. Only employees who reported their job or organization provided opportunities to use their creativity were allowed to continue the survey. Out of 305 initial responses collected, those with too much missing data were deleted, which finally left 278 responses for statistical analyses. To examine the validity of the measurements, confirmatory factor analysis was first conducted. Next, to test the hypothesized relationships, multiple hierarchical regression analyses were conducted. Results - As hypothesized, both intrinsic and extrinsic motivation had positive effects on creativity. It was shown that contingent rewards did not influence the positive relationship between intrinsic motivation and creativity, but did significantly moderate the relationship between extrinsic motivation and creativity in a way that tangible rewards strengthened the relationship while intangible rewards mitigated the same relationship. Conclusions - This research enhances our understanding on the relationship between motivation type, rewards, and creativity. Intrinsically motivated employees showed a high level of creativity regardless of whether rewards were expected or not. In contrast, extrinsically motivated employees showed more or less creative behavior depending on whether they were expected to have tangible or intangible rewards. As extrinsic motivation is typically associated with tangible rewards such as pay, promotion, etc., tangible rewards were seen to be more effective in promoting creative performance from extrinsically motivated employees than intangible rewards. Our findings make a significant theoretical contribution to reconcile prior inconsistent findings. Furthermore, they provide useful insights for managers and organizations into developing effective strategies for facilitating employee creativity.

A Study on Design Direction of e-Portfolio Based on the Current State Analysis of Portfolio Application of Domestic Elementary, Middle, and High School (국내 초.중등학교의 포트폴리오 활용 실태 분석에 기반한 e-포트폴리오 설계 방향에 관한 연구)

  • Kim, Sang-Su;Kim, Young-Hak
    • The Journal of the Korea Contents Association
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    • v.7 no.12
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    • pp.83-94
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    • 2007
  • The portfolio can be used as a methodology supporting the learning of constructivism. Recently, the use of portfolios has been increased gradually in the education field, but a study on the current state analysis and design direction of portfolios leaves much to be desired. In this paper, we analyze statistical data on the portfolio application of teachers in domestic elementary, middle, and high school. We also propose a design direction of e-portfolio needed in the society of knowledge information based on this analysis. The results of research show that the following problems will be improved: understanding portfolio, analyzing the current state according to the types of portfolio application, designing a distinguished system according to the level of school, expanding education of teachers with high career, and developing a guide helper. The design of total system that combines the learning and evaluation is needed to improve a problem that spends lots of time to make portfolio, and operates temporally and formally achievement evaluation. In addition, the design of e-portfolio supporting efficiently interaction and self-directed teaming is required.