• 한국산업보건학회지
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• 제18권3호
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• pp.239-247
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• 2008

Low back disorders (LBDs) have been the most common musculoskeletal problem in Korean workplaces. It affects many workers, and is associated with high costs to many companies as well as the individual, which can negatively influence even the quality of life of workers. The _evaluation of low back disorder risk associated with manual materials handling tasks can be performed using variety of ergonomic assessment tools such as National Institute for Occupational Safety and Health (NIOSH) Revised Lifting Equation (NLE), the Washington Administrative Code 296-62-0517 (WAC), the Snook Tables etc. But most of these tools provide limited information for choosing the most appropriate assessment method for a particular job and in finding out advantage and disadvantage of the methods, and few have been assessed for their predictive ability. The focus of this study was to _evaluate spinal loads in real time with lifting and pulling heavy cow leathers in variety of postures. Data for estimating mean trunk motions were collected as employees did their work at the job site, using the Lumbar Motion Monitor. Eight employees (2 males, 6 females) were selected in this study, in which the load weight and the vertical start and destination heights of the activity remained constant throughout the task. Variance components (three dimensional spaces) of mean trunk kinematic measures were estimated in a hierarchical design. They were used to compute velocity and acceleration of multiple employees performing the same task and to repetitive movements within a task. Therefore, a results of this study could be used as a quantitative, objective measure to design the workplace so that the risk of occupationally related low back disorder should be minimized.

• International Journal of Contents
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• 제8권1호
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• pp.23-29
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• 2012

Multiple expression levels of genes obtained using time series microarray experiments have been exploited effectively to enhance understanding of a wide range of biological phenomena. However, the unique nature of microarray data is usually in the form of large matrices of expression genes with high dimensions. Among the huge number of genes presented in microarrays, only a small number of genes are expected to be effective for performing a certain task. Hence, discounting the majority of unaffected genes is the crucial goal of gene selection to improve accuracy for disease diagnosis. In this paper, a non-Gaussian weight matrix obtained from an incremental model is proposed to extract useful features of multivariate time series microarrays. The proposed method can automatically identify a small number of significant features via discovering hidden variables from a huge number of features. An unsupervised hierarchical clustering representative is then taken to evaluate the effectiveness of the proposed methodology. The proposed method achieves promising results based on predictive accuracy of clustering compared to existing methods of analysis. Furthermore, the proposed method offers a robust approach with low memory and computation costs.

• 한국정보과학회논문지:데이타베이스
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• 제28권3호
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• pp.430-448
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• 2001

차량 항법 시스템에서 가장 중요한 기능중의 하나는 현재 위치로부터 목적지까지의 가능한 경로들 최단경로를 계산하는 일이다. 차량 항법 시스템의 중요한 어려움 중 하나는 대용량 디지털 로드맵상에서 최단경로를 구할 때 많은 계산 시간이 소요된다는 점이다. 차량 항법 시스템은 실시간 시스템이므로, 제한 시간을 만족하여 최소 비용 경로를 계산하는 것은 매 우 중요하다. 본 논문에서는 대용량의 디지털 로드맵(Road Maps)에서 최단 경로 계산을 효 율적이고 빠르게 하기 위해서 디지털 로드맵을 효율적으로 계층 구조화하는 HiTi(Hierarchical MulTi) 그래프 모델을 개발하였다. 제안된 HiTi 그래프 모델에 기반을 둔 SPAH라는 새로운 최단 경로 알고리즘을 제안하고, SPAH가 계산한 최단경로의 최적성 (Optimality)을 증명하였다. SPAH의 성능분석을 통하여 SPAH가 기존의 다른 최단 경로 계 산 알고리즘들 보다 훨씬 빠르게 최단경로를 계산한다는 것을 보여주었다. HiTi 그래프 방 법은 여러 가지 측면에서 다른 유사한 방법들과 상세하게 성능실험을 통하여 장.단점이 비 교 분석되어 졌다.

• Safety and Health at Work
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• 제9권4호
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• pp.427-433
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• 2018

Background: The purpose of this study was to identify the influence of workers' perceived workload, accident experiences, supervisors' safety leadership, and an organization's safety climate on the cognitive and emotional risk perception. Methods: Six hundred and twenty employees in a variety of manufacturing organizations were asked to complete to a questionnaire. Among them, a total of 376 employees provided valid data for analysis. To test the hypothesis, correlation analysis and hierarchical regression analysis were used. Statistical analyses were conducted using IBM SPSS program, version 23. Results: The results indicated that workload and accident experiences have a positive influence and safety leadership and safety climate have a negative influence on the cognitive and emotional risk perception. Workload, safety leadership, and the safety climate influence perceived risk more than accident experience, especially for the emotional risk perception. Conclusion: These results indicated that multilevel factors (organization, group, and individual) play a critical role in predicting individual risk perceptions. Based on these results, therefore, to reduce risk perception related with unsafe behaviors and accidents, organizations need to conduct a variety of safety programs that enhance their safety climate beyond simple safety-related education and training. Simultaneously, it needs to seek ways to promote supervisors' safety leadership behaviors (e.g., site visits, feedback, safety communication, etc.). In addition, it is necessary to adjust work speed and amount and allocate task considering employees' skill and ability to reduce the workload for reducing risk perception.

• 대한인간공학회지
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• 제28권4호
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• pp.147-154
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• 2009

The tactical computer is currently being developed and installed in armored vehicles and tanks for reinforcement. With the tactical computer, Korea Army will be able to grasp the deployment status of our forces, enemy, and obstacles under varying situations. Furthermore, it makes the exchange of command and tactical intelligence possible. Recent studies showed that the task performance is greatly affected by the user interface. The U.S. Army is now conducting user-centered evaluation tests based on C2 (Command & Control) to develop tactical intelligence machinery and tools. This study aims to classify and regroup subordinate menu functions according to the user-centered task performance for the Korea Army's tactical computer. Also, the research suggests an ergonomically sound layout and size of main touch buttons by considering human factors guidelines for button design. To achieve this goal, eight hierarchical subordinate menu functions are initially drawn through clustering analysis and then each group of menu functions was renamed. Based on the suggested menu structure, new location and size of the buttons were tested in terms of response time, number of error, and subjective preference by comparing them to existing ones. The result showed that the best performance was obtained when the number of buttons or functions was eight to conduct tactical missions. Also, the improved button size and location were suggested through the experiment. It was found in addition that the location and size of the buttons had interactions regarding the user's preference.

• 기본간호학회지
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• 제19권2호
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• pp.253-260
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• 2012

Purpose: This study was done to identify the impact of resourcefulness and communication style on nursing performance in nurses working in hospitals. Method: Though a convenience sampling method 312 nurses were recruited between from July 4 and 17, 2011. Data were collected using a questionnaire, which included items on work related characteristics, resourcefulness, communication style, and nursing performance. Data were analyzed using t-test, ANOVA, Scheffe test, Pearson correlation coefficient and hierarchical regression analysis. Results: The major findings of this study were as follow; 1) There were significant relationships between nursing performance and resourcefulness ($p$<.001), informative communication style ($p$<.001), affiliativeness communication style ($p$<.001), and dominance communication style ($p$<.001). 2) The nursing performance was significantly associated with career in current department, resourcefulness, informative communication style, affiliativeness communication style, and dominance communication style in capability which explained 45.6% of variance in nursing performance. Conclusion: The results of this study demonstrate a relationship between resourcefulness, communication style, and nursing performance in hospital nurses indicating the need to use the study results to plan programs to prompt nurses in their use of resourcefulness and communication style in nursing care.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3656-3671
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• 2016

Most of the research in the area of wireless communications exclusively relies on simulations. Further, it is essential that the mobility management strategies and routing protocols should be validated under realistic conditions. Most appropriate mobility models play a pivotal role to determine, whether there is any subtle error or flaw in a proposed model. Simulators are the standard tool to evaluate the performance of mobility models however sometimes they suffer from numerous documented problems. To accomplish the widely acknowledged lack of formalization in this domain, a Coloured Petri nets (CPNs) based random direction mobility model for specification, analysis and validation is presented in this paper for wireless communications. The proposed model does not suffer from any border effect or speed decay issues. It is important to mention that capturing the mobility patterns through CPN is challenging task in this type of the research. Further, an appropriate formalism of CPNs supported to analyze the future system dynamic status. Finally the formal model is evaluated with the state space analysis to show how predefined behavioral properties can be applied. In addition, proposed model is evaluated based on generated simulations to track origins of errors during debugging.

• The Journal of Korean Physical Therapy
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• 제25권5호
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• pp.343-351
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• 2013

Purpose: This study was designed to measure the level of professional autonomy regarding physical therapists and to determine the association of organizational and occupational characteristics of the profession with its professional autonomy. Methods: We utilized a structured questionnaire survey of physical therapists (280 persons) in Jeju province. Data were collected from June 25 to July 14 in 2012. An additional 173 (63%) of them were used in the final analysis. Using PASW 18.0, descriptive and Hierarchical Linear Model were performed. Results: Regression analysis Result of Factors influencing Physiotherapist Professionalism, refresher training course (t=4.27), formalization (t=3.13), task significance (t=3.39), and autonomy (t=4.17) had a positive effect. Autonomy (${\beta}$=0.33) and formalization (${\beta}$=0.33) exerted the greatest influence. Conclusion: The survey regarding organizational and job characteristics showeds that occupational reeducation, formalization, and self- regulation constitute a positive part of what the professional autonomy is to be upheld. Results of the survey imply that in order to establish professional autonomy for the profession of physical therapist, the organization must make various efforts to beef up the exclusive knowledge and technology, and professional norms of the occupation that are considered essential for specific problem solving.

• 중환자간호학회지
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• 제7권2호
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• pp.24-33
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• 2014

Purpose: The purpose of this study was to identify the relationship between organizational culture and workplace bullying of intensive care unit (ICU) nurses. Methods: A secondary analysis was conducted using three different data sets on workplace bullying of hospital nurses. This analysis focused on the relationship between organizational culture and workplace bullying of 240 ICU nurses. The original data were collected using self-reporting questionnaires and were analyzed using hierarchical multiple regression. Results: ICU nurses were aware of their organizational culture as being rank-oriented, relationship-oriented, innovation-oriented, and task-oriented in that order. The results showed that 15.0% of the ICU nurses reported being victims of workplace bullying, mostly work-related bullying. The perception of a relationshiporiented culture explained a variance of 29% in the workplace bullying of ICU nurses. Conclusion: The findings suggest that ICU nurses who are strongly aware of a relationship-oriented culture would experience less workplace bullying. Further research is needed to develop interventions that can foster a relationship-oriented culture in ICUs.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.984-994
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• 2020

It is reported that about 20% of accidents at nuclear power plants in Korea and abroad are caused by human error. One of the main factors contributing to human error is fatigue, so it is necessary to prevent human errors that may occur when the task is performed in an improper state by grasping the status of the operator in advance. In this study, we propose a method of evaluating operator's fitness-for-duty (FFD) using various parameters including eye movement data, subjective fatigue ratings, and operator's performance. Parameters for evaluating FFD were selected through a literature survey. We performed experiments that test subjects who felt various levels of fatigue monitor information of indicators and diagnose a system malfunction. In order to find meaningful characteristics in measured data consisting of various parameters, hierarchical clustering analysis, an unsupervised machine-learning technique, is used. The characteristics of each cluster were analyzed; fitness-for-duty of each cluster was evaluated. The appropriateness of the number of clusters obtained through clustering analysis was evaluated using both the Elbow and Silhouette methods. Finally, it was statistically shown that the suggested methodology for evaluating FFD does not generate additional fatigue in subjects. Relevance to industry: The methodology for evaluating an operator's fitness for duty in advance is proposed, and it can prevent human errors that might be caused by inappropriate condition in nuclear industries.