• Title/Summary/Keyword: Visual force

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Effects of Visual Information Blockage on Landing Strategy during Drop Landing (시각 정보의 차단이 드롭랜딩 시 착지 전략에 미치는 영향)

  • Koh, Young-Chul;Cho, Joon-Haeng;Moon, Gon-Sung;Lee, Hae-Dong;Lee, Sung-Cheol
    • Korean Journal of Applied Biomechanics
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    • v.21 no.1
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    • pp.31-38
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    • 2011
  • This study aimed to determine the effects of the blockage of visual feedback on joint dynamics of the lower extremity. Fifteen healthy male subjects(age: $24.1{\pm}2.3\;yr$, height: $178.7{\pm}5.2\;cm$, weight: $73.6{\pm}6.6\;kg$) participated in this study. Each subject performed single-legged landing from a 45 cm-platform with the eyes open or closed. During the landing performance, three-dimensional kinematics of the lower extremity and ground reaction force(GRF) were recorded using a 8 infrared camera motion analysis system (Vicon MX-F20, Oxford Metric Ltd, Oxford, UK) with a force platform(ORG-6, AMTI, Watertown, MA). The results showed that at 50 ms prior to foot contact and at the time of foot contact, ankle plantar-flexion angle was smaller(p<.05) but the knee joint valgus and the hip flexion angles were greater with the eyes closed as compared to with the eyes open(p<.05). An increase in anterior GRF was observed during single-legged landing with the eyes closed as compared to with the eyes open(p<.05). Time to peak GRF in the medial, vertical and posterior directions occurred significantly earlier when the eyes were closed as compared to when the eyes were open(p<.05). Landing with the eyes closed resulted in a higher peak vertical loading rate(p<.05). In addition, the shock-absorbing power decreased at the ankle joint(p<.05) but increased at the hip joints when landing with the eyes closed(p<.05). When the eyes were closed, landing could be characterized by a less plantarflexed ankle joint and more flexed hip joint, with a faster time to peak GRF. These results imply that subjects are able to adapt the control of landing to different feedback conditions. Therefore, we suggest that training programs be introduced to reduce these injury risk factors.

Efficacy Evaluation of Anti-wrinkle Products in Japan

  • Masaki Hitoshi
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.29 no.2 s.43
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    • pp.67-77
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    • 2003
  • Two categories of cosmetic products, cosmetics and quasi-drugs, have been established by the Ministry of Health, Labor and Welfare (MHLW) in Japan. Japanese pharmaceutical law has defined that products categorized as cosmetics do not exhibit any effects on human skin. In fact, cosmetic products are not permitted to claim any efficacy. On the other hand, products in the quasi-drug category can claim several efficacies such as anti-inflammatory effects, whitening/lightning effects, hair growth effects and so on. Unfortunately, the Japanese MHLW has not yet approved the efficacy of anti-aging/anti-wrinkle effects as a claim point. However, the population is aging, and the demand for anti-aging/anti-wrinkle products is increasing year by year. Japanese cosmetic companies have proposed to the MHLW that anti-aging/anti-wrinkle agents be approved as a claim concept of a quasi-drug. However, unified evaluation methods for anti-aging/anti-wrinkle effects have not been established. Currently, each company evaluates the efficacy of products/materials using their own original methods. Thus, to request approval of the MHLW, the establishment of a unified evaluation method is needed. Consequently, the Japan Cosmetic Industry Association (JCIA) has established a task force to develop guidelines for evaluating anti-wrinkle effects in 1998. In conclusion, the JCIA would like to adopt visual and image analysis scales to evaluate the anti-wrinkle effects objectively. Generally, wrinkles are roughly classified into three groups as fine wrinkles, linear deep wrinkles and crow's feet. However, academic societies of dermatology or cosmetics have not yet established a definition of wrinkles in Japan. Thus, in advance of setting up an evaluation method, the definition of wrinkles f3r evaluation must be decided. Wrinkles are defined by the task force of the JCIA as follows; furrows that people can recognize visually and that appear on the forehead, the corners of the eyes and the backs of the neck with aging. In addition, furrows are emphasized by exposure to solar light and by dry conditions. Visual evaluation is the most sensitive method and can be applied to most types of wrinkles. However, visual evaluation is hard to express digitally as results. Besides, in the case of image analysis, comparisons of data obtained from distinct examinations can not be done, because data from image analysis are relative values. Thus, to enhance the reliability of the evaluations, the adoption of an objective scale was required. The principle of the evaluation method is to analyze images taken from silicone replicas of wrinkle areas using several parameters, such as the proportion of the wrinkle $area({\%})$, the mean depth of the wrinkles (mm), the mean depth of the deepest wrinkle (m) and the deepest point on the deepest wrinkle. Lights are shown on the skin replica from an orthogonal direction of the main orientation of the wrinkle, and the resulting shadow images are quantified by the image analysis method. To increase the precision of the data or to allow comparisons of independent examinations, a scale with furrows of several depths, 200, 400, 600, 800, and $1000{\mu}m$, is adapted in the evaluation system. I will explain the guidelines established by the JCIA in the presentation.

Classification of Tire Tread Wear Using Accelerometer Signals through an Artificial Neural Network (인공신경망을 이용한 가속도 센서 기반 타이어 트레드 마모도 판별 알고리즘)

  • Kim, Young-Jin;Kim, Hyeong-Jun;Han, Jun-Young;Lee, Suk
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.2_2
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    • pp.163-171
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    • 2020
  • The condition of tire tread is a key parameter closely related to the driving safety of a vehicle, which affects the contact force of the tire for braking, accelerating and cornering. The major factor influencing the contact force is tread wear, and the more tire tread wears out, the higher risk of losing control of a vehicle exits. The tire tread condition is generally checked by visual inspection that can be easily forgotten. In this paper, we propose the intelligent tire (iTire) system that consists of an acceleration sensor, a wireless signal transmission unit and a tread classifier. In addition, we also presents classification algorithm that transforms the acceleration signal into the frequency domain and extracts the features of several frequency bands as inputs to an artificial neural network. The artificial neural network for classifying tire wear was designed with an Multiple Layer Perceptron (MLP) model. Experiments showed that tread wear classification accuracy was over 80%.

Development of an Advanced Early Rehabilitation Training System for Postural Control Using a Tilting Bed

  • Yu, Chang-Ho;Kim, Kyung;Kim, Yong-Yook;Kwon, Tae-Kyu;Hong, Chul-Un;Kim, Nam-Gyun
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2440-2443
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    • 2005
  • We propose a new early rehabilitation training system for postural control using a tilting bed and a force plate. The conventional rehabilitation systems for postural control cannot be applied to the patients lying in bed because the rehabilitation training using those systems is possible only when the patient can stand up by himself or herself. Moreover, there has not existed any device that could provide the sense of balance or the sensation of walking to the patients in bed. By using a tilting bed, a visual display, and a force plate, we have developed a new rehabilitation training system for balance control of the patients in bed providing sense of balance and the sensation of walking to the patient. Through the experiments with real people, we verified the effectiveness of the new early rehabilitation training system. The results showed that this system is an effective system for the early rehabilitation training and that our system might be useful as clinical equipment.

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Effect of a Therapeutic Exercise Program on the Functional Recovery Following Temporomandibular Joint Surgery (측두하악관절 수술 후 관절 운동프로그램이 기능회복에 미치는 영향)

  • Oh, Duck-Won;Kim, Ki-Song;Lee, Gyu-Wan;Jung, Nak-Su
    • Physical Therapy Korea
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    • v.6 no.3
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    • pp.94-109
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    • 1999
  • The purposes of this study were to assess the effect of therapeutic exercise and to offer an approach to the physical therapy and rehabilitation procedure of the temporomandibular joint (TMJ) following surgery. In this research, 42 patients with TMJ surgery were assigned one of two groups. The experimental group included 21 patients who performed therapeutic exercise, and the control group included 21 patients who did not perform therapeutic exercise. Conservative therapy such as an ice pack, a hot pack, and pulsed ultrasound was applied to both groups. Treatment was applied twice a day during the admission period and, after discharge, everyday for six weeks. Visual analogue scale (VAS), incisal biting force, and joint ROM were measured before surgery and at 30 days after surgery. The results were as follows: VAS (p<0.05), mouth opening (p<0.01), lateral excursion to unaffected side (p<0.05), and protrusion (p<0.05) between experimental group and control group showed statistically significant differences. Incisal biting force and lateral excursion to affected side between experimental group and control group showed no statistically significant difference.

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Wire frame drive unit ofa SMA-based 3D shape display (SMA을 이용한 3차원 형상제시기의 와이어프레임 구동 유닛)

  • Chu Y.J.;Kim Y.M.;Song J.B.;Park S.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.439-440
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    • 2006
  • This research proposes a novel method of shape display to present 3-dimensional objects. Shape displays allow us to feel the actual volume of the object, unlike conventional 2D visual displays of 3D objects. The proposed method employs a wire frame structure to present 3D objects. The wire frame is composed of small units driven by shape memory alloy(SMA) actuators. The drive unit is analogous to the agonist-antagonist system of animal musculoskeletal systems, where the SMA actuators serve as agonist and antagonist muscles. The force in the SMA actuator is controlled by electrical current. The drive unit is equipped with the locking mechanism so that it can sustain the external force exerted by the user as well as the own weight of the wire frame structure. By controlling the current into the SMA actuator and locking mechanism, we call control the angle of the drive unit. A chain of drive units enables presentation of 2 dimensional objects. 3 dimensional presentations are possible by collecting the chains of drive units.

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Development of SMA-based Wireframe Structure for 2D Shape Display (2차원 형상 제시를 위한 SMA에 기반한 와이어프레임 구조의 개발)

  • Chu, Yong-Ju;Song, Jae-Bok
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.5
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    • pp.82-88
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    • 2008
  • This paper proposes a novel method of 2 dimensional shape display. Shape displays allow us to feel tile actual volume of the object, unlike conventional 2D visual displays of 3D objects. The proposed method employs a wireframe structure to present 2D or 3D objects. The wireframe is composed of small units driven by shape memory alloy (SMA) actuators. The drive unit is analogous to the agonist-antagonist system of animal musculoskeletal systems, where the SMA actuators serve as agonist and antagonist muscles. The force in the SMA actuator is controlled by electrical current. The drive unit is equipped with the locking mechanism so that it can sustain the external force exerted by the user as well as the own weight of the wireframe structure. By controlling the current into the SMA actuator and locking mechanism, we can control the angle of the drive unit. A chain of drive units enables presentation of 2 dimensional objects. 3 dimensional presentations are possible by collecting the chains of drive units.

Experimental Observations of Boiling and Flow Evolution in a Coiled Tube

  • Ye, P.;Peng, X.F.;Wu, H.L.;Meng, M.;Gong, Y. Eric
    • International Journal of Air-Conditioning and Refrigeration
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    • v.16 no.1
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    • pp.22-29
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    • 2008
  • A sequence of visually experimental observations was conducted to investigate the flow boiling and two-phase flow in a coiled tube. Different boiling modes and bubble dynamical evolutions were identified for better recognizing the phenomena and understanding the two-phase flow evolution and heat transfer mechanisms. The dissolved gases and remained vapor would serve as foreign nucleation sites, and together with the effect of buoyancy, centrifugal force and liquid flow, these also induce very different flow boiling nucleation, boiling modes, bubble dynamical behavior, and further the boiling heat transfer performance. Bubbly flow, plug flow, slug flow, stratified/wavy flow and annular flow were observed during the boiling process in the coiled tube. Particularly the effects of flow reconstructing and thermal non-equilibrium release in the bends were noted and discussed with the physical understanding. Coupled with the effects of the buoyancy, centrifugal force and inertia or momentum ratio of the two fluids, the flow reconstructing and thermal non-equilibrium release effects have critical importance for flow pattern in the bends and flow evolution in next straight sections.

The Effects of Gaze Direction on the Stability and Coordination of the Lower Limb Joint during Drop-Landing (드롭랜딩 시 시선 방향의 차이가 하지관절의 안정성과 협응에 미치는 영향)

  • Kim, Kewwan;Ahn, Seji
    • Korean Journal of Applied Biomechanics
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    • v.31 no.2
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    • pp.126-132
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    • 2021
  • Objective: The purpose of this study was to investigate how three gaze directions (bottom, normal, up) affects the coordination and stability of the lower limb during drop landing. Method: 20 female adults (age: 21.1±1.1 yrs, height: 165.7±6.2 cm, weight: 59.4±5.9 kg) participated in this study. Participants performed single-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Kinetic and kinematic data were obtained using 8 motion capture cameras and 1 force plates and leg stiffness, loading rate, DPSI were calculated. All statistical analyses were computed by using SPSS 25.0 program. One-way repeated ANOVA was used to compared the differences between the variables in the direction of gaze. To locate the differences, Bonferroni post hoc was applied if significance was observed. Results: The hip flexion angle and ankle plantar flexion angle were significantly smaller when the gaze direction was up. In the kinetic variables, when the gaze direction was up, the loading rate and DPSI were significantly higher than those of other gaze directions. Conclusion: Our results indicated that decreased hip and ankle flexion angles, increased loading rate and DPSI when the gaze direction was up. This suggests that the difference in visual information can increase the risk of injury to the lower limb during landing.

Teleoperation Using Reconstructed Graphic Model (재구성된 그래픽 모델을 이용한 원격제어)

  • Chung, Seong-Youb;Yoon, Hyun-Joong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.9
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    • pp.3876-3881
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    • 2012
  • In typical master/slave teleoperation systems, a human operator generally manipulates the master to control the slave through the visual information like camera image. However, the operator may get into trouble due to the limited visual information depending on the camera positions and the delay on the visual information because of low communication bandwidth. To cope with this inherit problem in the camera-based teleoperation system, this paper presents a teleoperation system using a reconstructed graphic model instead of the camera image. The proposed teleoperation system consists of a robot control module, a master module using a force-reflective joystick, and a graphic user interface (GUI) module. The graphic user interface module provides the operator with a 3D model reconstructed using a small set of sensing data received from the remote site. The proposed teleoperation system is evaluated through a peg-in-hole assembly task.