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

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.45-59
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• 2007

The operating tasks of overhead crane have caused undue stress to the operators from physical, mental, and environmental workload. Existing workload assessment models for musculoskeletal disorders such as OWAS, RULA, and QEC have limited applicability to the crane operating tasks because they focus mainly on physical factors and do not consider the relative importance of each factor. The present study was to develop a workload assessment model customized to overhead crane operation, following a systematic process: (1) analyzing task characteristics, (2) selecting workload factors, (3) developing assessment methods, (4) establishing action levels, and (5) computerizing the assessment model. Based on literature review, worksite survey, and focus group interview, 4 physical factors (awkward posture, static posture, repetitive motion, and excessive force), 6 mental factors (visual demand, auditory demand, task complexity and difficulty, time urgency, work schedule related stress, and safety related stress), and 4 environmental factors (noise, vibration, dust, and temperature) were selected and their rating scales and relative weights were determined. Then, based on the workload assessment results of 8 overhead cranes operated at different workplaces, the action levels of each factor category were established. Finally, the crane operation assessment model was computerized for effective analysis and report preparation. The present approach is applicable to develop a customized workload assessment model for an operating task under consideration.

• Journal of Drive and Control
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• v.19 no.4
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• pp.29-35
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• 2022

In this paper, we developed a workload index for monitoring the durability test using operation information of an excavator. First, the acceleration and cylinder pressure were selected as load factors by analyzing operation data. Through load correlation analysis according to each load factor, Root Mean Square (RMS) and Work Load Range (WLR) were respectively derived as a load feature representing mechanical load. In addition, the workload index was used to quantify load features. For applying the workload index to monitoring, a real-time monitoring system consisting of sensors and embedded controller was installed on the excavator and the system was integrated with a remote monitoring environment using a wireless network. Results of load monitoring and analysis verified that the developed workload index was effective from the viewpoint of the relative comparison of the workload.

• Journal of Korean Society of Transportation
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• v.19 no.3
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• pp.45-58
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• 2001

Subjective mental workload assessment technique becomes a standard human factors and human-machine interface evaluation tool for the evaluation of ITS(Intelligent Transport Systems)-oriented information systems as well as the drivers visual activity analysis, physiological indices(GSR, EEG, ECG, etc.), secondary task performance, reaction time. vehicle control parameters(speed, steering behavior, accelerator control) that are widely applied for transportation and vehicle systems to evaluate the safety, to decide the system or design alternatives, and to establish the design guidelines. This paper reviewed and compared the most globally employed four mental workload assessment techniques that have been designed for the use of various human-machine systems and ITS-oriented in-vehicle information systems. NASA-TLX(National Aeronautics and Space Administration-Task Load Index). SWAT(Subjective Workload Assessment Technique), MCH(Modified Cooper-Harper) scale, and recently developed RNASA-TLX(Revision of NASA-TH) were compared in terms of sensitivity and subjective evaluations to derive the human-machine interface evaluation guidelines for the application of ITS-oriented in-vehicle information systems. Then, experiment results supported that RNASA-TLX is the prospective tool for the mental workload assessment of ITS-oriented in-vehicle information systems.

• Journal of Korean Society of Transportation
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• v.35 no.6
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• pp.545-556
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• 2017

Various assessment indexes have been developed and utilized to evaluate the driver workload. However, existing workload assessment indexes do not fully reflect driving habits and driving patterns of individual drivers. In addition, there exists significant differences in the amount of workload experienced by a driver and the ability to overcome the driver's workload. To overcome these limitations associated with existing indexes, this study has developed a novel workload assessment index to reflect an individual driver's driving pattern. An average of the absolute values of the steering velocity for each driver are set as a threshold value in order to reflect the driving patterns of individual drivers. Further, the sum of the areas of the steering velocities exceeding the threshold value, which is defined as erratic steering area (ESA) in this study, was quantified. The developed ESA index is applied in evaluating the driver workload of manually driven vehicles in automated vehicle platooning environments. Driving simulation experiments are conducted to collect drivers' responsive behavior data which are used for exploring the relationship between the NASA-TLX score and the ESA by the correlation analysis. As a result, ESA is found to have the greatest correlation with the NASA-TLX score among the various driver workload evaluation indexes in the lane change scenario, confirming the usefulness of ESA.

• Korean Management Science Review
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• v.12 no.1
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• pp.61-77
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• 1995

The Ergonomic Workload Stress Index (EWSI) was developed to predict the existence and level of the ergonomic workload stress in the workplace. To determine the validity of model, the values of the EWSI and two other similar techniques, Job Severity Index (JSI) and Physical Work Stress Index (PWSI) were evaluated in two actual industrial environments. The results from the validation study provide further substantial evidence that two techniques, JSI and PWSI, which have similar objective considerations, are significantly associated with the value of the EWSI among the employees participating in the experimentation.

• IE interfaces
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• v.10 no.1
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• pp.145-154
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• 1997

In developing the HMI(Human-Machine Interface) evaluation system for the IVNS(In-Vehicle Navigation System), design guidelines and evaluation methods are the most crucial problems for its use and efficiency. As the part of this system, focused on the final product of the database, subjective mental workload assessment is seriously considered to evaluate the driver's own driving task using the IVNS. This paper suggests the methodology for the ergonomic assessment of the IVNS that corresponds to the subjective measurement of the driver's mental workload by rating his or her own driving task. For this approach, Revision of NASA-Task Load Index(RNASA-TLX) was developed which translated and revised the version of NASA-TLX that is generally accepted an efficient and powerful method for evaluating the in-vehicle information systems. To verify the RNASA-TLX, an experiment was conducted in a real road situation, because the result of the laboratory approach is uncertain and has the differences from the real road test.

• Journal of the Ergonomics Society of Korea
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• v.29 no.2
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• pp.203-210
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• 2010

For the development of a better product which fits to the target user population, physical workloads such as reach and visibility are evaluated using digital human simulation in the early stage of product development; however, ergonomic workload assessment mainly relies on visual observation of reach envelopes and view cones generated in a 3D graphic environment. The present study developed a quantitative assessment method of physical workload in a digital environment and applied to the evaluation of a Korean utility helicopter (KUH) cockpit design. The proposed assessment method quantified physical workloads for the target user population by applying a 3-step process and identified design features requiring improvement based on the quantified workload evaluation. The scores of physical workloads were quantified in terms of posture, reach, visibility, and clearance, and 5-point scales were defined for the evaluation measures by referring to existing studies. The postures of digital humanoids for a given task were estimated to have the minimal score of postural workload by finding all feasible postures that satisfy task constraints such as a contact between the tip of the index finger and a target point. The proposed assessment method was applied to evaluate the KUH cockpit design in the preliminary design stage and identified design features requiring improvement. The proposed assessment method can be utilized to ergonomic evaluation of product designs using digital human simulation.

• Proceedings of the ESK Conference
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• 1996.10a
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• pp.41-46
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• 1996

This paper suggests the methodology for the ergonomic assessment of the navigation system driver that corresponds to the subjective measurement of the driver's mental workload by rating his or her own driving task. For this approach, Revision of NASA-Task Load Index (RNASA-TLX) was developed which translated and revised the version of NASA-TLX that is generally accepted an efficient and powerful method for evaluating the in-vehicle information system. To venify RNASA- TLS, an experiment was conducted in a real road situation, because the result of the laboratory approach is uncertain and has the differences from the real road test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.194-195
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• 2015

Methods for measuring the physical workload of construction workers are classified into posture assessment techniques (i.e., OWAS, RULA, etc.) and physiological measurement techniques (i.e., EMG, heart rate, etc.). The one does not quantify the workload on a specific body part of a worker by considering the weight of the hand tools or materials on hand and time for holding a particular posture. This paper presents a procedure for evaluating a physical demand using the electromyography (EMG) sensor. This study compares the EMG measurement and the posture assessment. The case study is carried out on a masonry operation.