• 대한인간공학회지
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• 제32권2호
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• pp.167-177
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• 2013

Objective: This study aims to compare the usefulness of subjective measures which are comprised of existing methods like NASA-TLX, Bedford-scale and ZEIS and newly developed method like DALI in measuring drivers' mental workload in terms of validity, sensitivity and diagnosticity. Background: Nowadays, with the development of intelligent vehicle and HMI, mental workload of driver has become more and more important. For this reason, the studies on drivers' mental workload about driving situation and the use of information technology equipment such as mobile phones and navigations were conducted intensively. However, the studies on measuring drivers' mental workload were rarely conducted. Moreover, most of studies on comparison of subjective measures were used with performance based measure. However, performance based measures can cause distraction effect with subjective measures. Method: Participants (N=19) were engaged in a driving simulation experiment in 2 driving contexts (downtown driving and highway driving context). The experiment has 2 sessions according to driving contexts. The level of difficulties by driving contexts were adjusted according to existence of intersections, traffic signs and signals, billboards and the number of doublings. Moreover, as criteria of concurrent validity and sensitivity, the EEG data were recorded before and during the sessions. Results: The results indicated that all subjective methods were correlates with EEG in high-way driving. On the contrary to this, in downtown driving, all subjective methods were not correlates with EEG. In terms of sensitivity, multi-dimensional scales (NASA-TLX, DALI) were the only ones to identify differences between high way and downtown driving. Finally, in terms of diagnosticity, DALI was the most suitable method for evaluating drivers' mental workload in driving context. Conclusion: The DALI as newly developed method dedicated to evaluate driver's mental workload was superior in terms of sensitivity and diagnosticity. However, researchers should consider the characteristics of each subjective method synthetically according to research objective by selecting the method in subjective measures. Application: The results of this study could be applied to the intelligent vehicle and next generation of HMI design to decrease mental workload of driver and for the development of new subjective method in vehicle domain.

• 대한교통학회지
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• 제19권3호
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• pp.45-58
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• 2001

교통시스템 및 차량의 인간-기계 상호작용 및 인간공학적 평가에 널리 사용되는 운전자의 시각행위분석, 생체신호측정(심박수, 호흡수, 뇌파, 피부전기반사 등), 부가작업의 수행도분석, 반응시간 분석, 차량조작변수 분석(속도, 핸들조작, 가속페달조작) 등의 방법들과 함께 운전자 판단에 의한 주관적평가(Subjective Mental Workload Assessment)는 기존 시스템의 평가뿐만 아니라, ITS(Intelligent Transport Systems) 기반 인간-기계 시스템(항법장치, Head-UP Display, AHS Flat Panel Display, Changeable Message Sign, Cellular Phone, 등)의 인간-기계 상호작용 평가, 안전도 평가, 경쟁시스템 및 디자인 대안의 의사결정, 설계가이드라인 제작 등을 위한 하나의 표준화된 평가도구로 자리 잡고 있다. 이에 본 연구에서는 가장 많은 적용빈도와 효과 및 감도를 제시하는 주관적 평가방법인 NASA-TLX (National Aeronautics and Space Administration-Task Load Index), SWAT(Subjective Workload Assessment Technique), MCH(Modified Cooper-Harper) scale, RNASA-TLX(Revision of NASA-TLX)를 대상으로 항법 장치를 사용한 운전자 부하 비교평가 실험결과를 이용하여, 제시된 방법들의 감도 및 피 실험자의 주관적 판단을 통한 상호 비교분석을 실시하였으며, 결과로 위에 제시된 방법들의 사용가이드라인과 ITS 기반 인간-기계 시스템의 인간공학적 평가를 위한 주관적 평가방법의 비교평가결과를 제시하였다.

• 감성과학
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• 제4권1호
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• pp.1-5
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• 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.

• 산업경영시스템학회지
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• 제21권45호
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• pp.145-154
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• 1998

The effects of secondary task on driving performance and subjective workload were investigated during a simulated driving. The driving performance was determined by the appropriateness of break timing. The driving simulator was provided by the Korea Road Traffic Safety Association. The subjective workload was tested by using a multidimensional measure such as NASA-TLX. Road was categorized into two types: narrow alley and wide street. The secondary task included pushing the number on the cellular phone, pushing radio channel, and conversing with a passenger. Seventeen subjects volunteered in the study. The data were analyzed by using SAS. Results showed that using the cellular phone and pushing channel during driving caused 3∼22% decline of driving performance and 42∼59% increase of subjective workload respectively. These results indicated that the secondary task could be potentially dangerous although there was not a significant performance decrease due to the notable increase of mental workload. In the future, if we can use a more sensitive and realistic driving simulator, the effects of secondary task under a dynamic driving situation can be investigated.

• 산업공학
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• 제10권1호
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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.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1996년도 추계학술대회논문집
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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.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.453-462
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• 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.

• 감성과학
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• 제26권4호
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• pp.51-70
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• 2023

본 연구에서는 운전 시뮬레이션을 사용하여 자율주행 환경을 구현한 후 3-수준 자율주행 조건에서 자율주행 차량 (automated vehicle: AV)으로부터 운전자에게 전달되는 제어권 인수 요구(takeover request: TOR) 정보의 양상(시각, 청각 및 시각+청각) 및 도로 형태(직선도로와 곡선도로)에 따라 운전자의 제어권 인수 시간(takeover time: TOT) 및 정신적 작업부하(제어권 인수 이후에 운전자들이 경험한 주관적 작업부하와 심장박동수에서의 변화)가 어떻게 차별화되는지 분석하였다. 본 연구의 결과를 요약하면 다음과 같다. 먼저, AV로부터 TOR이 제시된 이후 실험참가자들이 보인 TOT에 대한 분석 결과, TOR 정보양상의 측면에서는 시각 정보가 가장 빠른 TOT를 이끌어 낸 반면 청각정보 조건에서 가장 느렸고, 도로 형태 측면에서는 직선도로 조건에 비해 곡선도로 조건에서의 TOT가 유의하게 더 느렸으며, 특히 청각 정보 조건에서 도로 형태에 따른 TOT에서의 차이가 가장 컸다. 둘째, 정신적 작업부하에 대한 분석 결과, TOR 정보가 시각 혹은 시각+청각적으로 제시된 조건에 비해 청각적으로 제시된 조건에서 주관적 작업부하 측정치와 심장박동수 변화 크기 모두 전반적으로 더 낮았고 특히, 심장박동수 변화의 경우 이러한 경향은 곡선도로 조건에서만 관찰되었다. 이러한 결과는 TOR 정보의 양상과 도로 형태에 따라 운전자의 TOT와 정신적 작업부하 수준이 달라질 수 있고, 특히 TOT가 빠를수록 정신적 작업부하 수준은 상대적으로 더 높아질 수 있음을 시사한다.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 추계학술대회논문집
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• pp.18-26
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• 1995

To quantify a mental workload for office workers, nine element tasks were classified for office work. There were oral comprehension, written comprehension, oral expression, written expression, calculation, memorization, thinking, and classification materials. Among nine element tasks, oral comprehension, written comprehension, written expression, and thinking were selected and the degrees of conflicts between concurrently performed element tasks were measured and analyzed through the experiment. The measures were performance and subjective rating. The results were as follows. The written comprehension- written expression pair was showed the highest conflict value in terms of performance and subjective rating. The written comprehension-thinking pair was the lowest conflict value in terms of performance, while the oral comprehension-thinking pair was the lowest condlict value in terms of performance, while the oral comprehension- written expression pair was the lowest conflict value in terms of subjective rating. The findings are expected to be used for assessing workload for the office work.

• 대한인간공학회지
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• 제31권2호
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• pp.353-362
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• 2012

Objective: The aim of this study is developing the navigation radar display of navy ship with ecological interface design (EID) framework. Background: Navy ship radar operator must perform navigation support tasks by monitoring the complex and diverse information presented on the radar display. Current radar display is limited in effective navigation aid and response to an unusual state immediately. It is necessary to develop an effective radar display. Method: Ten navy radar operators performed a series of trials in a low-fidelity radar simulation in which they attempted to solve the problems of current navigation situation. Results: The result demonstrated that the ecological interface's performance was better than the existing radar display on performance time and subjective mental workload. Conclusion: This study expand EID study field to navy ship radar display and confirm ecological display is better than existing radar display in performance time, subjective mental work load. Application: The result of this study may help to improve navy ship navigation radar display currently in use.