Issues : JET is a peer-reviewed, open-access scientific journal : Journal of Ergonomic Technology (JET)

Journal of Ergonomic Technology (JET)
ISSN 2432-1575


Validity and reliability of Leap Motion Controller for assessing grasping and releasing finger movements
Publish Date : 2017/10/04  Vol.17
Authors : 
Shuntaro OKAZAKI, Faculty of Human Sciences, Waseda University, Saitama, Japan
Yoshihiro MURAOKA, Faculty of Human Sciences, Waseda University, Saitama, Japan
Risa SUZUKI, Faculty of Human Sciences, Waseda University, Saitama, Japan
Report Outline : 
Objective: The leap motion controller (LMC) is a motion sensor that has recently become available and has advantages in terms of cost, size, and accuracy. However, it has not been fully investigated whether the LMC has sufficient accuracy for clinical assessments, particularly finger flexion and extension, which are important for diagnosis and prognosis in stroke or cerebral palsy patients. Herein, we have tested the validity and reliability of the LMC for measuring the grasp and release of finger movements.
Materials and methods: A healthy participant repeated finger flexion and extension movements, and his fingertip position was measured using an LMC from the palmar, ulnar, and dorsal sides of the hand. The fingertip position was also measured using an electromagnetic motion tracker and a video. The finger movement detected by the LMC was compared with those detected by the other instruments.
Conclusions: The LMC had a higher reliability in detecting the fingertip position by sensing it from the palmar or dorsal side of the hand, compared with the ulnar side. In the palmar/dorsal side measurements, an underestimation in the amplitude of the finger movement was shown in the middle range of its excursion compared to video-detected movement. However, the underestimation resulted in a highly correlated, proportional bias, especially in the palmar-side measurement, and could be calibrated by a nonlinear regression analysis. The palmar side measurement was thus the most suitable for evaluating the finger flexion and extension. We concluded that by taking into consideration the range of excursion and appropriate calibration, the validity and reliability of the LMC is sufficient for the quantitative evaluation of finger flexion and extension in laboratory experiments and also in clinical settings.

Keywords: Motion capture; Spasticity; Grasping; Bland–Altman plot
Count : 1178
Ergonomic evaluation of mobile work type office environments
Publish Date : 2017/09/23  Vol.17
Authors : 
Satoru SAITO, Department of Arts and Science, Faculty of Fundamental Science Engineering, Waseda University
Hiroki KITAJIMA, Labor and Science Research Institute
Toshiki YAJIMA, Kokuyo Corporation Furniture Business Hadquarters
Junichi NINOMIYA, Inaba International Corporation
Kunihisa NAKAYAMA, YAMAGIWA Corporation
Sachiyo FURUSAKA, WFM Women's Facility Management/Fulliaison
Reiko MITSUYA, Science and Technology Research Institute, Waseda University
Report Outline : 
Purpose: In recent years, there have been changes in awareness and institutional systems relating to work due to factors such as innovation in IT technology and adoption of work-life balance. In particular, some companies have introduced a new mobile work-style where employees are able to work anytime, anywhere. The aims of this research were to ascertain the current situation based on an ergonomic survey of workers who work in the mobile work-style, and to identify problems, and propose solutions.
Experiment participants and method: Our aim was to ascertain the current situation in offices by measuring satisfaction in terms of factors such as the comfort, fatigue, and ease-of-use of equipment and office furniture for people working in all workplace environments, not just conventional fixed offices. To achieve this, we prepared and administered questionnaires to 115 employees at two private companies which are especially committed to using the mobile work-style.
Results: Chairs and desks are found to influence the satisfaction by Structural Equation Modeling. The present survey found that the effects due to lighting/furniture and the satisfaction of network environment remarkably influenced the workers' satisfaction.
Conclusion: The current status of workers working in the mobile work-style was ascertained using a survey questionnaire. As a result, two points became clear. First, the physical environment in a company has a major impact on satisfaction. Second, is the inadequate understanding and low level of concern for ergonomics among workers. As a solution for the first, the possibilities are: (1) Improvement of worker satisfaction through proper layout/design and furniture/fixtures, (2) Improvement of work efficiency, such as the ability to concentrate and ease of viewing monitor screens through proper lighting, and improvement in peace-of-mind such as a sense of ease or pleasantness, and (3) improvement of satisfaction by developing the network environment and improving factors such as stress due to no assigned seats. A reduction in stress in office environments can be expected by adopting, as a measure to resolve the above two issues, company-wide education in the need for and awareness of using adjustment methods for chairs and other furniture, and equipment which is suited to the body.

Keywords: Mobile work-style, Office, Satisfaction
Count : 519
Basic study on improving sound localisation accuracy for musical tones by adding broadband noise
Publish Date : 2017/03/02  Vol.17
Authors : 
Hidenobu Takao*, Kanagawa Institute of Technology
Ryosuke Katayama, Kanagawa Institute of Technology
Report Outline : 
Purpose: When presenting a virtual auditory display (VAD) to a user who has difficulty using visual information, such as a visually impaired individual, an acoustic head related transfer function (HRTF) is necessary for vertical localisation. However, measurement of the HRTF is time consuming and costly. Because HRTFs differ between individuals, the use of another person’s HRTF reduces the accuracy of localisation. In this study, we propose and evaluate an extremely simple method for improving the accuracy of virtual sound localisation on the vertical plane using the same HRTF for various individuals, which may help with the use of a VAD.
Subjects and method: Six male university students (mean age of 22.5±2.5 years) with normal hearing and sight participated in the experiment, during which they wore blindfolds. Sound localisation accuracy was compared among three different conditions: presentation of a tone alone (tone condition), presentation of broadband noise alone (noise condition), and mixed presentation of a tone and broadband noise (mixed condition). Two types of playback system were used: a speaker array and virtual conditions (hearing binaurally through headphones). The stimuli were presented from a total of 13 different directions on the median plane at 10° intervals, from -60° (lower side) to 60° (upper side).
Results: As sound sources were presented farther from 0° in either direction, the target direction offset from 0° was more underestimated. It was found that in the virtual condition, the superimposition of musical tones and broadband noise significantly improved localisation accuracy compared with presenting each alone.
Conclusion: The present study demonstrated that when presenting virtual sound without personalising the HRTF, the extremely simple method of adding broadband noise markedly improves sound localisation accuracy on the vertical plane directly ahead of a subject.
Keywords: Virtual Auditory Display, Visual Impairment, Sound Localisation, 3D Sound, Binaural, Augmented Reality.
Count : 833
Evaluation of anatomical training for nursing students using unfixed lung, trachea, and larynx of swine
Publish Date : 2017/01/15  Vol.17
Authors : 
Masaaki TAKAYANAGI*, Department of Anatomy, Faculty of Medicine, Toho University,
Megumi SUGAHARA, Toho University Omori Medical Center
Manami NOZAKI, Dept of Fundamental Nursing, Faculty of Nursing, Toho University
Satomi KOBAYASHI, School of Nursing, Tokyo Eisei Gakuen College
Tomokazu KAWASHIMA, Department of Anatomy, Faculty of Medicine, Toho University
Hideo HOSHI, Department of Anatomy, Faculty of Medicine, Toho University
Tadanobu Chuyo KAMIJO, Department of Anatomy, Faculty of Medicine, Toho University
Fumi SATO, Department of Anatomy, Faculty of Medicine, Toho University
Report Outline : 
Objectives: Anatomy and physiology are fundamental subjects for establishing a foundation of knowledge for nursing. We have conducted anatomical training using unfixed respiratory internal organs (lung, trachea, and larynx) of swine in order to provide anatomy education to nursing students, since nursing students in Japan are not able to dissect the human body for learning. The objective of this study was to evaluate anatomical training of participating students and instructors, in order to inform development of an educational system effective at teaching anatomy of the respiratory system, and to enhance educational technique.
Subjects and methods:Grade 1 nursing students participated in an anatomy practicum using unfixed respiratory systems of swine (dissection, identification of the parts, labelling, measurement, and recording), after prior study of a textbook and distributed the manual for this anatomical training. We conducted a survey using a questionnaire with five-point Likert scale responses to investigate the benefit of the anatomical training among 425 nursing students who participated in the anatomy practicum. We also interviewed 5 instructors to evaluate the anatomical training.
Conclusions: The percentage of students who evaluated the anatomical training as meaningful were 95.4%, 94.1%, and 88.8% for lung, trachea, and larynx, respectively (average 92.8%). Our results suggest that the anatomical training was meaningful for learning anatomy among nursing students. In particular, many students were interested in the air injection demonstration using unfixed lung and segmental bronchus, where movement of the lung can be clearly observed, providing a strong learning opportunity. This demonstration is one of the most popular training experiences among the students. The demonstration enhances understanding of the concept of the pulmonary segmentation, shrinkage of the lung, and pneumothorax, as well as the dynamic image of change of the lung during respiration.
Keywords:Anatomical education, Nursing students, Respiratory system, Lung, Swine
Count : 760
Basic study on the effects of the use of BGM in auditory user interface on user’s memory and learning of directory hierarchy
Publish Date : 2016/12/31  Vol.16
Authors : 
Hidenobu Takao, Kanagawa Institute of Technology
Ryosuke Katayama, Kanagawa Institute of Technology
Toshimitsu Yamaguchi, Niigata University
Yoshimichi Ogawa, Kanagawa Institute of Technology
Takashi Matsuo, Kanagawa Institute of Technology
Katsumi Takahashi, Kanagawa Institute of Technology
Report Outline : 
Purpose: To provide cues to users for grasping the directory hierarchy in the operating environments of information technology devices when it is extremely difficult to use the sense of sight, we devised a user interface having a type of auditory landmark by playing simple music with no particular semantic structure as background music (BGM) for specific hierarchies. We performed a basic study of the effect of BGM on the users’ recall and learning of directory hierarchies and of the item names residing in them.
Subjects and method: The subjects were 12 healthy male university students between the ages of 21 and 22 (six for each of the experiment conditions). To avoid influencing the test results, we selected subjects who were not information science or music majors. We prepared a four-level tree-structured directory hierarchy, which was structured such that the first level had two branches, the second level had three branches, and the third level had three branches. There were 30 nodes and 80 items. We used information science terminology for the item names. The item names were read aloud using a screen reader. The arrow keys, enter key, and backspace key were used to move inside and between directories. We tested tasks of recall and learning of the directory hierarchy under two conditions: 1) with BGM (BGM was presented in three places in the hierarchy) and 2) without BGM. We performed six trials in total, two trials each day for three days.
Conclusion: Our findings are summarised as follows: (1) Memorising and learning by mapping the spatial arrangement of the directory with BGM enhanced the users’ spatial perception of the directory structure. (2) As a result, learning performance increased approximately 20% on an average. (3) This increased relatively the cognitive processing resources for applying the item names into memory, and learning efficiency increased by an average of approximately 30%.

Keywords: Auditory user interface, Non-visual user interface, Visual impairment, Human memories, Learning, Directory hierarchy
Count : 897
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