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Volume 34, Issue 1
Displaying 1-6 of 6 articles from this issue
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Masaki ENDO, Yuko FUJIGAKI1998 Volume 34 Issue 1 Pages 1-8
Published: February 15, 1998
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSIn this study, task characteristics of mental work are classified in order to establish an effective way to measure mental workload. Rasmussen's model is used to classify mental work into skill-based, rule-based, and knowledge-based tasks. Experiments are designed by considering these three levels of task characteristics, and the performance for each task is measured. The results show that for skill-based or rule-based tasks, changes of performance during one-hour experiments are small, whereas for knowledge-based tasks, changes are big. The graphs of accumulated performances illustrate the characteristics of each task. The results of our investigation on subjective symptoms, especially concerning “sleepiness and dullness”, differed for each of the tasks. These results indicate that the classification of mental work by using Rasmussen's model is useful for identifying the characteristics of the mental tasks, which is needed for selecting an effective method of measuring mental strain.View full abstractDownload PDF (5351K) -
Keiko ISHIHARA, Mitsuo NAGAMACHI, Hirokazu OSAKI, Shigekazu ISHIHARA, ...1998 Volume 34 Issue 1 Pages 9-16
Published: February 15, 1998
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSYellowish view of elderly people is simulated by using colored cellophane, whose transmission is equivalent to crystalline lens of a person around 75 years old. Subjects had meals at their home, went shopping and walked in the town with wearing yellow cellophane on their eyes, and investigated the influences on their daily life. It is found (1) changed colors' appearance, (2) difficulty in discrimination of colors, (3) difficulty in handling things without solid shapes (e. g. liquid), (4) failing of depth perception, and (5) difficulty in reading back-lighted signs. Concretely, difficulties in daily life are such that misjudge in freshness of foods and quantity of drinks, mistakes in goods selection at shops, and slow at meeting bumps on roads. An experiment was carried out on judgement of colors (same/different) by elderly men who were 80 to 86 of age. It is found as a result that elderly people tend to misjudge the colors mistaken in the simulation: yellow and white, blue and green, dark blue and black, and purple and dark red. In the interview, the elderly mentioned the difficulties in their daily lives due to their misjudgment of colors that was suggested in our simulation.View full abstractDownload PDF (2474K) -
(Part. 2) The indispensable measurement items of the lower bodyMiyuki BEPPU, Haruko MAKABE1998 Volume 34 Issue 1 Pages 17-27
Published: February 15, 1998
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSThis is a second report on selections of indispensable measurement items for clothing design for the lower body. Subjects are 791 young women, ages 20 to 22. The principal component analysis was performed on the 23 measurements on the lower body and 22 measurements on the shilhouetter photography. The analysis shows five components: 1. a size factor. 2. a shape factor. 3. a posture factor. 4. a hip shape factor. 5. position of the hip relative to the crural.
Results shows that the indispensable measurement items are: waist girth, hip girth, the distance between the waist line and the hip line (front, back and side), total crotch length, anterior crotch length, the difference of the back waist height from the front waist height, hip slope and the projection of the hip.View full abstractDownload PDF (11386K) -
Hiroyuki UMEMURO, Katsura IWASAKI, Takao ENKAWA1998 Volume 34 Issue 1 Pages 29-36
Published: February 15, 1998
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSUnderstanding quantitative and qualitative differences of information and their influence on productivity is important for efficient information supply to office workers. This study shows a method to classify information into efficient and inefficient information based on the task processing model. If the procedure to process some kinds of information to obtain outputs is explicitly defined in the task processing model, such information is classified as efficient information. The others are classified as inefficient information. Inefficient information can be divided into related information and nonessential information, depending on its relation with the task processing model. An experiment was carried out using order quantity decision task of inventory management jobs with different sets of information given. Results show that efficient information reduces costs but increases processing time. Inefficient information increases costs when a high amount of efficient information is also supplied, but increases processing time when the efficient information supplied is low. Workers with poor performance tend to refer to inefficient information more often.View full abstractDownload PDF (3299K) -
Haruo SHINODA, Mitsuteru KOKUBUN, Shigeru HAGA1998 Volume 34 Issue 1 Pages 37-44
Published: February 15, 1998
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSThere are two standpoints of view for the measurement of mental work load (MWL). One deals with the task demand and the other measures the subject's mental fatigue as an after effect. We focused on the task demand and expanded the concept to the task difficulty and duration. A dual task that is composed of pursuit tracking task as a primary task and memory retrieval task as secondary one was carried out using a computer display and a hand-made controller over 3 blocks (one block is about 10 minutes). The level of task difficulty stood at three (low, mid, and high) based on the stability of control dynamics. The reaction patterns to each task condition was examined in terms of the following indexes; performance on the task, subjective evaluations of the task load, emotional state, and physiological indexes (event related potentials: ERP, and heart rate). The results indicated that the Japanese version of the NASA-task load index score for the primary task was increased and P300 amplitude of ERP for the secondary task was decreased as the task difficulty increased. On the other hand, the interaction between work duration and task difficulty was reflected in the following points; 1) decreasing awareness in low and middle difficulty level, and 2) decreasing feeling of relaxation and increasing irritability in high difficulty level. Subjective fatigue increased only according to the work duration. These results suggested the necessity to separate task difficulty from work duration in the sensitivity on measures of MWL.View full abstractDownload PDF (7999K) -
Yasuaki FUKUTA, Takao OHKUBO, Shigemasa HARA1998 Volume 34 Issue 1 Pages 45-52
Published: February 15, 1998
Released on J-STAGE: March 12, 2010
JOURNAL FREE ACCESSFive types of experimental tasks are examined to make clear a relation between learning and lengths in interruption periods during learning. Individual time variations in the learning process is estimated from the rate of variability, δ, for analyzing the experimental results, and learning performance is analyzed according to the proposed work achievement method. To comprehend the relation with interruption learning quantitatively, we propose the evaluation model chart leading to interrupted lerning and various coefficients.
Our results are summarized as the following. (1) Interruption learning was analyzed with the work achievement method for 5 kinds of task with different contents and factors. (2) When evaluating the influence of interruption learning according to job tasks, using work achievement, Q, longer interruption periods are found to correspond to lower, Q, values in both form perception and spatial aptitude tests. Regarding other tasks, no interruption learning effect was observed. (3) The examination of the influence of interruption learning according to WF showed that tasks requiring form perception or spatial aptitude ability were influenced by interruption learning, while those requiring manual dexterity or the ability to do delicate work were not. (4) An evaluation model chart for interruption learning, and various coefficients are proposed.View full abstractDownload PDF (901K)
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