• 제목/요약/키워드: psychophysical

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Effect of Trunk and Upper Arm Angle on Lifting Capacity

  • Chang, Seong Rok
    • International Journal of Safety
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    • 제10권1호
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    • pp.32-35
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    • 2011
  • Lifting capacity and difficulty of task are influenced by body posture. In RULA and REBA, the body was divided into segments which formed two groups, A and B. Group A includes the upper and lower arm and wrist while group B includes the neck, trunk and legs. This ensures that whole body posture is recorded so that any awkward or constrained posture of the legs, trunk or neck which might influence the posture of the upper limb. This study aimed to measure MVC (maximum voluntary contraction) and subjective judgment in psychophysical method (Borg's scale) according to trunk and upper arm angle and to analyze results statistically. The results of this study were that lifting capacity was more influenced by interaction of body posture rather than angles of each part, and MVC variation according to trunk and upper arms angles should different patterns. This means that we consider the interaction of trunk angles and upper arm angles when we access risk factors of the postures. This survey would be also the basic data to evaluate difficulty of lifting tasks according to body postures ergonomically.

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복합 이미지에 대한 Perceptibility와 Acceptability 측정 (Perceptibility and Acceptability Tests for the Quality Changes of Complex Images)

  • Kim Dong Ho;Park Seung Ok;Kim Hong Seok;Kim Yeon Jin
    • 한국광학회:학술대회논문집
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    • 한국광학회 2003년도 하계학술발표회
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    • pp.80-81
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    • 2003
  • The psychophysical experiments were carried out by a panel of eleven observers on the image difference pairs displayed on the LCD (liquid crystal display)to quantify the quality changes of complex images imparted by the typical image processing operations. There were six different kinds of pairs according to their original image. The three types of visual tests performed were: pair-to-pair comparison of image differences for ordering the differences between images introduced by single or combination of image lightness change, contrast change, blurring, and sharpening, perceptibility and acceptability tests using ascending or descending series of image difference pairs ordered according to the size of their visual differences. (omitted)

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Resolution of Temporal-Multiplexing and Spatial-Multiplexing Stereoscopic Televisions

  • Kim, Joohwan;Banks, Martin S.
    • Current Optics and Photonics
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    • 제1권1호
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    • pp.34-44
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    • 2017
  • Stereoscopic (S3D) displays present different images to the two eyes. Temporal multiplexing and spatial multiplexing are two common techniques for accomplishing this. We compared the effective resolution provided by these two techniques. In a psychophysical experiment, we measured resolution at various viewing distances on a display employing temporal multiplexing, and on another display employing spatial multiplexing. In another experiment, we simulated the two multiplexing techniques on one display and again measured resolution. The results show that temporal multiplexing provides greater effective resolution than spatial multiplexing at short and medium viewing distances, and that the two techniques provide similar resolution at long viewing distance. Importantly, we observed a significant difference in resolution at the viewing distance that is generally recommended for high-definition television.

Ergonomic Assessment for Manual Materials Handling of Livestock Feed by Elderly Farmers in Korea

  • Kim, Insoo;Lee, Kyung-Suk;Kim, Kyung-Ran;Chae, Hye-Seon;Kim, Sungwoo
    • 대한인간공학회지
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    • 제34권3호
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    • pp.279-291
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    • 2015
  • Objective: The purpose of the study is to evaluate appropriate weight for aged farmers in manually handling livestock feed in bags using ergonomic methods. Background: In the livestock industry in South Korea, despite the trend of aging of labor manpower, heavy items are still manually handled in many farms. In particular, among stockbreeding works, the handling of feed in bags weighing 25~30kg is reported as a cause of frequent injuries and musculoskeletal system diseases. However, studies on the standard for recommended weight allowed considering the physical characteristics of aged farmers older than 60 years with greatly decreased physical strength and muscle strength are insufficient. Method: To evaluate appropriate weight for handling of heavy livestock feed in bags, physical techniques for measuring recognized levels of physical work loads, the NLE (NIOSH lifting equation) a method that is an observation type technique, and an ergonomic modeling technique to predict compressive force imposed on L5/S1 were used. Subjects who participated in the experiment were organized into two groups of males/females with mean age exceeding 60 years, and lifting tasks were evaluated for nine weight levels. Results: Based on the results of psychophysical measurement, females showed a tendency of more drastic increases compared to males when weight was over 19kg. The results of estimation of regression models for the weight, 18.0 kg ($r^2=0.97$) and 15.3kg ($r^2=0.97$) were evaluated as stable load for males and females, respectively. In addition, both the observation type evaluation and ergonomic model evaluation showed stable loads in a range of 15~18kg. Conclusion: Given the results of the study, the weight of the feed in bags currently distributed to farms can become a cause of not only overexertion but also farm work related disasters such as musculoskeletal disorders and safety accidents. Providing livestock feed in bags weighing not more than 19kg for aged farmers is judged desirable, and managerial improvement for this matter is considered necessary. Application: The results of the present study can be utilized as useful data for institutional improvement of the weight of livestock feed in bags.

Demystifying an Appropriate Use of a Performer's 'Energy' Where the Performer's Body Becomes 'Real'

  • Son, Bong-Hee
    • International Journal of Advanced Culture Technology
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    • 제10권2호
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    • pp.148-153
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    • 2022
  • This thesis investigates the meaning of a performer's energy taking into an account of the full bodily engagement as the flow of energy and/or psychophysical readiness focusing specifically on the significance of qualitative bodily transformation. In this contemporary era, the dominance of performer training and its approaches to acting/training has very frequently meant that how to play a character in a textual based approach by emphasizing on interpreting and impersonating the role as real as possible. In this sense, as a performer trainer, from my observation and research findings shows that it is common for the term energy is not to be motivated by what a performer's body needs within a specific moment in specific performance which they are working on. To address the problematic issues, this thesis begins by interrogating the practical meaning of transformation with addressing the principle and process of movement by means of the flow of energy on stage. For a performer, inhabiting/integrating his/her body and mind as oneness and/or unity means s/he sincerely encounter, confront, and therefore listen to his/her body in here and now. Because since the performer's physical appearance completely defined his/her psychological state, no one can play either the past or the future in the moment. In this manner, an appropriate use of energy synonymous with the flow of energy correspondence with the given time and space in which the performer's body informs and initiates movement as necessary action. To be precise, the performer's bodily movement either visible or invisible in a sense of training and rehearsal is perceived as attaining or achieving psychophysical involvement as the full body engagement which enable to make the event happen in the right moment. Here, this thesis argues that the significance of a performer's inner intensity reminds us of the necessity of qualitative transformation on which the performer could discover his/her own mode of awareness as well as a way his/her body function in the given circumstance. From this point of view, this research finding would advocates that the performer's body maintains in the field of energy flow where his/her conscious effort and/or mindfulness disappear. The performer's movement is a manifestation of the whole bodily engagement by means of being as real in that moment rather than representing reality.

뇌세포의 전기자극에 의한 맹인의 시감각 회복에 관한 연구 (Artificial Vision : Electrical Stimulation of the Visual Cortex)

  • 차기철
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1991년도 춘계학술대회
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    • pp.28-30
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    • 1991
  • 뇌의 시세포를 전기적으로 자극할때 작고 환한 섬광을 보게된다. 이 원리를 이용하여 전기 핀 배열판으로 축구 경기장의 전광판 같은 이미지를 만들어 맹인을 위한 기능적 시각, 걷기 혹은 글 읽기를 가능케 할 수 있다. 유타대학 생체공학과는 인공시각 연구에서 최고의 역사를 가지고 있다. 최근에 개발된 실리콘 전극 배열판은 가까운 장래의 인체 실험을 남겨놓고 있다.

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외부 부하가 부과된 어깨 자세의 심물리학적 불편도 평가 (Evaluation of Varying Shoulder Postures with External Loads using a Psychophysical Method)

  • 류태범;박용주;나석희;정민근;기도형
    • 대한인간공학회지
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    • 제24권2호
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    • pp.9-15
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    • 2005
  • The purpose of this study is to quantitatively investigate perceived discomfort of complex shoulder postures with external loads and to propose a preliminary evaluation scheme of shoulder postures. Twelve healthy male adults participated in an experiment to rate their perceived discomfort of shoulder postures. The independent variables were shoulder flexion angle(45, 90 and 150$^{\circ}$), adduction/abduction angle(-30, -10, 0, 30 and 60$^{\circ}$), and external load(0, 1.5 and 3.0kg). The results revealed that the flexion angle, external load and their interaction significantly affected the perceived discomfort(p$<$0.05) but the effect of adduction/abduction angle on the discomfort was not significant(p$>$0.05). The effect of external load was much larger than that of any other factor with explaining about 81% of the total variation of discomfort scores. Based on the experimental results a preliminary scheme was presented to evaluate the stress of shoulder postures with external loads.

조향 휠 수직 진동의 체감량 평가에 관한 연구 (A Study on the Evaluation of Sensation Magnitude of Vertical Vibration of a Steering Wheel)

  • 장한기;홍석인
    • 한국자동차공학회논문집
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    • 제15권6호
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    • pp.108-113
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    • 2007
  • This study aims to find equivalent comfort contours, reciprocal of frequency weighting curves, for vertical steering wheel vibration. Psychophysical responses were measured from twelve male subjects by using magnitude estimation of relative discomfort due to vertical steering wheel vibrations of magnitude of 0.1 to 1.58 $m/s^2$ in the frequency range of 4 to 250 Hz. Relative discomfort were estimated with a reference vibration of 0.4 $m/s^2$ at 31.5 Hz. Equivalent comfort contours were produced from the median of sensation magnitudes judged by twelve subjects, which showed variation in the shapes with increase of vibration magnitude. A shape of the contour came close to the perception threshold curve with decrease of vibration magnitude. When the vibration magnitude increases, the shape changed close to those in the references of Hong and et al (2003). It is also recommended frequency weighting curves for vertical steering wheel vibration must be expressed as a function of vibration magnitude as well as frequency.

휠로더 자동변속기의 변속품질 평가 방법에 관한 연구 (A Study on the Quantitative Assessment Method for Shift Quality of Automatic Transmission in a Wheel Loader)

  • 이종찬;김관수;임종형;이효원;권영민;김형준;이민희
    • 대한기계학회논문집A
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    • 제32권7호
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    • pp.561-568
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    • 2008
  • The quality of the automatic transmission shift for a wheel loader has been generally evaluated by driver's perception. However the subjective evaluation of the drivers is not always directly related to the shift quality. It is necessary to set up the method for an objective assessment of the shift quality. In this paper, a quantitative assessment method has been developed for the shift quality of the automatic transmission in a wheel loader. The indices for the evaluation were selected through the various tests like the acceleration and the turbine rpm as well as the subjective evaluation of the driver, and were validated by the correlation between subjective and objective assessments using a psychophysical power law. Based on this method, the shift quality of a wheel loader has been evaluated quantitatively under various shift conditions.

A Heuristic Approach for Simulation of time-course Visual Adaptation for High Dynamic Image Streams

  • Kelvin, Bwalya;Yang, Seung-Ji;Choi, Jong-Soo;Park, Soo-Jun;Ro, Yong-Man
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2007년도 춘계학술발표대회
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    • pp.285-288
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    • 2007
  • There is substantial evidence from earlier researches that older adults have difficult seeing under low illumination and at night, even in the absence of ocular diseases. During human aging, there is a rampant decrease in rod/cone-meditated adaptation which is caused by delayed rhodopsin regeneration and pigment depletion. This calls for a need to develop appropriate visual gadgets to effectively aid the aging generation. Our research culminates its approach from Pattanaik's model by making extensions to temporal visual filtering, thereby simulating a reduction of visual response which comes with age. Our filtering model paves way and lays a foundation for future research to develop a more effective adaptation model that may be further used in developing visual content adaptation aids and guidelines in MPEG 21 environment. We demonstrate our visual model using a High Dynamic Range image and the experiment results are in conversant with the psychophysical data from previous vision researches.

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