• Journal of the Ergonomics Society of Korea
• /
• v.29 no.4
• /
• pp.435-444
• /
• 2010

To identify and evaluate the risk factors in WMSD work, a number of ergonomic workload evaluation methods have been developed. In the legal examination of WMSD risk factors, simple observational workload evaluation methods are widely used instead of using costly measurement equipments such as EMG and motion analyzer. The simple workload evaluation methods can be categorized into three groups; risk factor checklist methods, posture observation methods, and manual material handling task evaluation methods. In terms of the categories, this survey summarized several representative workload evaluation methods and compared them each other. Then some industrial application cases referring each the workload evaluation methods were surveyed. Due to the characteristics of each method, the selection and application procedure of workload evaluation method should be appropriate for the corresponding work. Therefore, some guidelines for the selection and application procedure of workload evaluation method were suggested.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.4
• /
• pp.687-691
• /
• 2010

Workload assessment is one of the important elements of the human factors evaluation for the nuclear power plants in operation. This paper describes a further study upon the additional elements of the workload which elements should be considered in the subjective workload assessment. We have tried to predict the burden of the work and to improve the work through a comparison of the objective workload and the subjective workload in the previous studies in nuclear power plants. However, there is a restriction to perform a precise assessment because of the limitations of the method itself. The objective workload assessment is performed by relative comparison using the quadrant analysis with objective workload and subjective workload because there were no clear criteria of objective workload assessment. And the subjective workload assessment is performed by NASA-TLX (NASA Task Load Index) which includes six evaluation dimensions of subjective workload. NASA-TLX is difficult to grasp the other aspects that could influence on the subjective workload because the analysis relies on predetermined assessment items. We conduct a factor analysis between the factors that affect the workload and the assessment adopted from ISO 10075 and NASA-TLX. At the same time, this study suggests other evaluation elements which can be added for subjective workload assessment except for evaluation elements of NASA-TLX.

• Proceedings of the ESK Conference
• /
• 1997.10a
• /
• pp.433-436
• /
• 1997

Automobile assembly tasks consist of many kinds of manual work which are very stressful to workers because of repetitive poor working postures and dealing heavy weights. To decrease the level of workload, it is necessary to evaluate the workload quantitatively. In this study, a workload evaluation method based on EMG was experimentally evaluated. We measured EMG at 6 main muscles with 2 healthy male workers during doing 9 assembly tasks, which were selected as high workload jobs. The tasks were decomposed into 36 elementary tasks. The workload was calculated through an equation with %MVIS and work duration time. To evaluate the result, subjective discomfort on the tasks was assessed by 29 workers. By the calculated workload, we were able to ranked the workload of tasks, elementary tasks. The comparison between the EMG-based workload and subjective rating showed a positive correlation(P-value=0.0246). We think it is possible to adapt the EMG-based workload evaluation technique to all assembly tasks by expending the experi- ment size.

• Journal of Korean Institute of Industrial Engineers
• /
• v.40 no.3
• /
• pp.325-332
• /
• 2014

High cognitive workload decreases a driver's ability of judgement and response in traffic situation and could result in a traffic accident. Electrocardiography (ECG) has been used for evaluation of drivers' cognitive workload; however, individual differences in ECG response corresponding to cognitive workload have not been fully considered. The present study developed an evaluation method of individual driver's cognitive workload based on ECG data, and evaluated its usefulness through an experiment in a driving simulator. The evaluation method developed by the present study determined the optimal ECG evaluation condition for individual participant by analysis of area under the receiver operating characteristic curve (AUC) for various conditions (total number of conditions = 144) in terms of four aspects (ECG measure, window span, update rate, and workload level). AUC analysis on the various conditions showed that the optimal ECG evaluation condition for each participant was significantly different. In addition, the optimal ECG evaluation condition could accurately detect changes in cognitive workload for 47% of the total participants (n = 15). The evaluation method proposed in the present study can be utilized in the evaluation of individual driver's cognitive workload for an intelligent vehicle.

• ETRI Journal
• /
• v.20 no.4
• /
• pp.346-360
• /
• 1998

It is challenging to parallelize problems with irregular computation and communication. In this paper, we propose an asynchronous algorithm for balancing unpredictable workload on distributed-memory machines. By using an initial workload estimate, we first partition the computations such that the workload is distributed evenly across the processors. In addition, we perform task migrations dynamically for adapting to the evolving workload. To demonstrate the usefulness of our load balancing strategy, we conducted experiments on an IBM SP2 and a Cray T3D. Experimental results show that our task migration strategy can balance unpredictable workload with little overhead. Our code using C and MPI is portable onto other distributed-memory machines.

• Nuclear Engineering and Technology
• /
• v.51 no.2
• /
• pp.453-462
• /
• 2019

Mental workload (MWL) is a major consideration for the user interface design in nuclear power plants (NPPs). However, each MWL evaluation method has its advantages and limitations, thus the evaluation and control methods based on multi-index methods are needed. In this study, fuzzy comprehensive evaluation (FCE) theory was adopted for assessment of interface designs in NPP based on operators' MWL. An evaluation index system and membership functions were established, and the weights were given using the combination of the variation coefficient and the entropy method. The results showed that multi-index methods such as performance measures (speed of task and error rate), subjective rating (NASA-TLX) and physiological measure (eye response) can be successfully integrated in FCE for user interface design assessment. The FCE method has a correlation coefficient compared with most of the original evaluation indices. Thus, this method might be applied for developing the tool to quickly and accurately assess the different display interfaces when considering the aspect of the operators' MWL.

• Science of Emotion and Sensibility
• /
• v.4 no.1
• /
• pp.1-5
• /
• 2001

The evaluation of mental workload is measured by subjective ratings, physiological signals. It takes long time to analysis the measured signals and is very tedious and time-consumming work. Therefore, to evaluate the affect of workload effectively, real-time measurement system is required. In this paper, real-time mental workload measurement system using cardiac autonomic indiced which reflect well the mental workload was developed and evaluated. Analyzed indices were HR, IBI, Lorentz plot, CSI, CVI, and LF/HF ratio of heart rate variability. The system was applied to evaluate the affect of arithmetic task and showed good results. This system was consisted of ECG amplifier, A/D converter, and personal computer, and algorithm was implemented using LabVIEW.

• IE interfaces
• /
• v.16 no.2
• /
• pp.222-228
• /
• 2003

Computer-dominated jobs and industrial automation have rapidly created work-related musculoskeletal disorders(WMSDs) and WMSDs are also founded in employees of other general industries. WMSDs has been growing problems for Korean industries with higher incidence rate every year. The objective of this paper is to analyze the effects of the neck muscle workload according to postures(joint angle) and load weights. Seven male students participated in this study. Neck workload was rated on each person using a Borg's CR-10 scale. ANOVA showed that the CR-10 ratings were statistically significant according to postures and load weights. To reduce the large number and severity of WMSDs, which employees have been experiencing, we need to redesign the job in workplace so that we can control hazards that are reasonably likely to be causing or contributing to the WMSDs. The results of this study can be used to establish the safety criteria of joint angle and weight of neck workload.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.4
• /
• pp.445-453
• /
• 2010

It is necessary to quantitatively evaluate the workload of workers in order to improve the level of safety and efficiency as well as to prevent workers from musculoskeletal disorders. The purpose of this study is to introduce biomechanical methods that are largely used to quantitatively evaluate workload. The biomechanical methods use kinematics and kinetics to analyze the movement and force of biomechanical body. Motion analysis, joint angle measurement, ground reaction force, mathematical model, and electromyography (EMG) were introduced as a tool or device for biomechanical evaluation. In this study, the special feature of each method was emphasized and important tips for field measurement were summarized. The information and technique disclosed in this summary can be used to evaluate and design the workplace better by effectively control the workload of field workers.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.17 no.30
• /
• pp.25-34
• /
• 1994

Mental workload has a improtant place in modern work environment such as human-computer interaction. Designing man-machine system requires knowledge and evaluation of the human cognitive process which controls information flow during our works. Many studies estimate reaction time as a index of menatal workload. This paper investigates what reflacts the workload of human information handling when the informations grow its degree. Experiment result introuce the memory time that explain the information-load more sensitive than react time. And react time shows learning effect but memory time does'nt show that effect So it can be concluded that cognitive learning or work schema needs more time to achieve dexterity than motor skill.