• Journal of the Ergonomics Society of Korea
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• v.4 no.2
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• pp.11-15
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• 1985

Nowadays, there are many situations which the conventional control system can't be applied any more (e.g. nuclear waste disposal sites, radioactive laboratories, the deep ocean and the vacuum of the outer space). New control system must be considered such as supervisory control system in those environment. Using computer graphic robot simulation, supervisory control which can cope with this situation is compared to manual control. As a performance measure of these comparisons, task time and task error are used. And task difficulties and time delay are considered as a variation factor. According to the result of this study, supervisory control is superior to manual control generally. Especially in the situation including task difficulties and time delay, the superiority is much greater.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.3
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• pp.267-274
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• 2014

The purpose of this study is to identify a relationship between the time taken and the characteristics of touch key for touch-screen-based in-vehicle information system (IVIS) and to suggest a new Fitts' law formula that is added a driving speed parameter. Many studies already have shown that Fitts' law is well fitted in various devices for primary tasks, but there is no study of Fitts' law for secondary task in dual-task situation. Fitts' law may not be applied to the secondary task as it is, because the secondary task performance can be affected by the amount of attention for the primary task. To verify this, we carried out an experiment that showed whether pointing task to touch-screen-based IVIS during driving is affected by driving speeds or not. In the experiment, 30 people were volunteered for participants and the participants carried out driving task and pointing task on the screen of IVIS simultaneously. We measured the time to point a touch key on IVIS for every condition (3 driving speeds${\times}5$ touch key sizes${\times}7$ distances between steering wheel and touch key). As a result, there was an effect of driving speed on the pointing time. As we extended the index of difficulty of the conventional Fitts' law formula by incorporating driving speed, we established an extended Fitts' law formula for pointing on IVIS, which showed better accordance with dual task situation. This study can be evidence that secondary task performance is affected by degree of concentration on primary task, and the extended Fitts' law formula can be useful to design interfaces of IVIS.

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.113-121
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• 1997

Human reliability attempts to make precise quantitative analyses and predictions of the performance of human-machine(or product) systems. In order to yield more precise human error analysis, precise human error probabilities(HEPs) must be used in the analysis. However, because human behavior is influenced by factors that are called performance shaping factors(PSFs), the effects of PSFs must be considered to obtain precise HEPs, These are called basic HEPs or situation-specific HEPs. This paper presents a theoretical method for obtaining basic HEPs (i.e. , considering PSFs) in quantitative human error analysis. In this method, the weight which characterizes the degree of importance of several PSFs is obtained by the analytic hierarchy process. The quality scores of PSFs in the task situation are obtained by percentile concept. These scores are used in conjunction with the relative Importance weights of PSFs to compute the composite quality percentile score of PSFs in the task situation. Then, a new mapping method of the composite quality percentile score of PSFs into a situation-specific basic HEP is proposed with a numerical example.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.2
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• pp.21-25
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• 2005

Human performance of system control under excessive mental-workload may differ from stable situation. In this study, design guidelines of secondary control system were introduced to enhance performance of safety control system. Under urgent situation, the first performance criterion is not a reaction time but safe control reaction that prevents system disaster. Therefore it is important to find out the facts that are mainly related system safety. Experimental results show performance of primary task didn't reflect whole system influence within a limited short reaction time. In this situation, the secondary task is more sensitive to system influence that varied with some factors of urgent status. Therefore, when a system proceeds to abnormal and unsafe status, and even more the reaction time is limited within a very short time to control the system, the estimation of human performance is more sensitive using secondary task performance then primary task performance. Those results mean it is required to develop various secondary tasks to design safety control systems preventing disaster, And also require many studies of estimation methods human performances especially when system status varies dangerous and/or unsafe situation.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.168-174
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• 2001

For human error analysis, the structure and situation of a task should be analyzed in advance. The paper introduces Structured Information Analysis (SIA) as a task analysis method for error analysis, and delineates the result of application on the emergency procedure of Korean Standard Nuclear Plants (KSNPs). From the task analysis about emergency procedure of KSNP, total 72 specific task goals were identified in the level of system function, and 86 generic tasks were classified from the viewpoint of physical sameness of the task description. Human errors are dependent on task types so that the result of task analysis would be used as a basis for the error analysis on the emergency tasks in nuclear power plants.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.126-132
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• 2005

The purpose of this study is to propose a method to evaluate task complexity using CIFs(Complexity Influencing Factors). We developed a method that CIFs can be used in the evaluation of task complexity using fuzzy linguistic approach. That is, a fuzzy linguistic multi-criteria method to assess task complexity in a specific task situation was proposed. The CIFs luting was assessed in linguistic terms, which are described by fuzzy numbers with triangular and trapezoidal membership function. A fuzzy weighted average algorithm, based on the extension principle, was employed to aggregate these fuzzy numbers. Finally, the method was validated by experimental approach. In the result, it was validated that TCIM(Tink Complexity Index Method) is an efficient method to evaluate task complexity because the correlation coefficient between task performance time and TCI(Task Complexity Index) was 0.699.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.415-420
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• 2012

It is important to understand the amount of time required to execute an emergency procedural task in a high-stress situation for managing human performance under emergencies in a nuclear power plant. However, the time to execute an emergency procedural task is highly dependent upon expert judgment due to the lack of actual data. This paper proposes an analytical method to estimate the operator's performance time (OPT) of a procedural task, which is based on a measure of the task complexity (TACOM). The proposed method for estimating an OPT is an equation that uses the TACOM as a variable, and the OPT of a procedural task can be calculated if its relevant TACOM score is available. The validity of the proposed equation is demonstrated by comparing the estimated OPTs with the observed OPTs for emergency procedural tasks in a steam generator tube rupture scenario.

• The Mathematical Education
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• v.44 no.1 s.108
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• pp.15-40
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• 2005

This study basically investigates the meaning and properties of performance task applicable to mathematics classroom and it finds out how to run effectively performance task activities included in the present mathematics textbooks. To accomplish this, this study deals with twelves kinds of mathematics textbooks for ninth graders and is proceeded on the basis of textbook analysis and teacher interview. Considering a situation that in future mathematics textbook would be developed, according to the analytic results of this study, common understanding of performance task and qualified performance task are needed, a variety of tasks classified by differentiated level are needed. In addition, each task should be dealt with the contents related to curious and interesting real-life situations. Furthermore, fairness of checking and recording should be established and teachers' positive attitudes to applying performance tasks to math class are needed.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.78-83
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• 2007

The purpose of present study was to investigate the characteristics of disfluency between the Korean-English bilingual and Korean monolingual children, matched by their chronological age with the bilingual children. Twenty-eight children, 14 bilingual children and 14 monolingual children participated in this study. The experimental tasks consisted of the play situation and the task situation. The conclusion is (a) The score of total disfluency of the bilingual was significantly higher than that of the monolingual. The score of normal disfluency of the bilingual was significantly higher than that of the monolingual. The most frequent type is Interjection in both groups. All shows higher score in the task situation than the play situation. The bilingual children have quantitative and qualitative differences in disfluency score and types from the monolingual. (b) The bilingual were divided into two groups such as 6 Korean-dominant bilingual and 8 English-dominant bilingual. All shows more disfluency in their non-dominant language. The most frequent type is Interjection in both groups. (c) The higher the chronological age and the expressive language test score is, the lower the disfluency score is. The earlier the exposure age to the 2nd language is, the higher the disfluency score is. There is no correlation between resident month at foreign country and the disfluency.

• Stress
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• v.27 no.2
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• pp.199-204
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• 2019

Backgoround: This study aimed to examine the influence of anxiety sensitivity on task performance and physiological stress response, and to assess the effect of depression in this process for the youth population. Methods: We presented participants with an uncontrollable stress situation where they were required to perform mental arithmetic, based on the Montreal Imaging Stress Task (MIST). A total of 29 participants volunteered for this study. They completed the Anxiety Sensitivity Index-Revised and Patient Health Questionnaire-9 to measure their levels of anxiety sensitivity and depression. Two saliva samples, one before and one after the experiment, were collected to assess the change in cortisol levels as an index of physiological stress response. Results: Participants with high anxiety sensitivity showed lower performance on the mental arithmetic tasks and a significant increase in a salivary cortisol level, compared to those with low anxiety sensitivity. Furthermore, cortisol levels showed a remarkable increase where high anxiety sensitivity was coupled with depressed mood. In other hands, the levels of cortisol remained unchanged despite high anxiety sensitivity with low depressed mood. Conclusions: Our results confirm that the interaction between anxiety sensitivity and depression affects participants' task performance and stress response, as measured through behavioral tasks and physiological data with self-report indices. Also, through the physiological data, we examined that those who have a high level of anxiety sensitivity showed maladaptive responses under high stressful situation.