• Title/Summary/Keyword: gravity center

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Effects of Visual Feedback-Based Balance Training on Balance in Elderly Fallers (시각되먹임 균형훈련이 낙상을 경험한 노인의 균형에 미치는 효과)

  • Lee, Sun-Woo;Lee, Kyoung-Jin;Song, Chang-Ho
    • Journal of muscle and joint health
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    • v.18 no.1
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    • pp.16-27
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    • 2011
  • Purpose: The purpose of this study was to investigate the effects of a visual feedbackbased balance training, using force platform biofeedback, on the postural balance of elderly faller. Methods: Fifty one community-dwelling older adults (aged 66-88 years) with a recent history of fall participated in the study. Participants were randomized to an experimental group (EG, n=25) and to a control group (CG, n=26). The EG participated in training sessions three times/week for 6 weeks. Visual feedbackbased balance training with the a computerized force platform with visual feedback screen was used in the experimental group. Static balance (center of gravity) and dynamic balance (Functional reach test, Timed "Up & Go" test, Berg balance scale) were assessed before and after end of training. Results: A significant improvement in static balance and dynamic balance were demonstrated within the EG (p<.05), but not in the CG. Conclusion: Visual feedback-based balance training may be an effective intervention to improve postural balance of elderly fallers.

Assessment of Problem Based Learning Application in Clinical Pharmacy Education (임상약학 교육에서의 문제중심학습 수업 방법 적용 평가)

  • Kim, Jung Tae;Kim, Jong Yoon;Kim, Myung Chun;Rhew, Ki Yon
    • Korean Journal of Clinical Pharmacy
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    • v.23 no.1
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    • pp.65-70
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    • 2013
  • Background: Colleges of Pharmacy in Korea have increased the number of years required for the degree from 4 years to 6 years in 2009. These changes are demanding revolution of education in pharmacology. The center of gravity is moving from medicine to application, theory to work. Problem-Based Learning is "learn to learn" working cooperatively in groups to seek solutions to real problems. PBL process cheers students to think critically to find optimal solution using appropriate learning resources. Method: Eighteen students in college of pharmacy are selected to participate in PBL lecture and take part in the survey about the effect of PBL in clinical pharmacy education. Results: General satisfaction score was high as four on a five-point scale, and students have improved on anxious about communication since the PBL classes compared to before of the lecture (P=0.037). Conclusion: PBL could be applied in clinical pharmacy education to progress student's participation and satisfaction. In addition this is improved communication skill in medical team during pharmacy practice.

Control of Mobile Manipulators for Power Assist Systems (파워 어시스트 시스템을 위한 이동 머니퓰레이터의 제어)

  • Lee, Hyeong-Gi;Seong, Yeong-Hwi;Jeong, Myeong-Jin
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.2
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    • pp.74-80
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    • 2000
  • In this paper, we present a control method of mobile power assist systems. Most of mobile power assist systems have a heavy base for preventing easy tumbling, so continual movement of the base during operations causes high energy consumption and gives the high risk of human injury. Furthermore, the slow dynamics of the base limits the frequency bandwidth of the whole system. Thus we propose a cooperation control method of the mobile base and manipulator, which removes the unnecessary movements of the base. In our scheme, the mobile base does not move until the center of gravity(C.G) of the system goes outside a safety region. When C.G. reaches the boundary of the safety region, the base starts moving to recover the manipulator's initial configuration. By varying the parameters of a human impedance controller, the operator is warned by a force feedback that C.G. is on the marginal safety region. Our scheme is implemented by assigning a nonlinear mass-damper-spring impedance to the tip of the manipulator. Our scheme is implemented by a nonlinear mass-spring impedance to the tip of the manipulator. The experimental results show the efficacy of the proposed control method.

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Area Extraction of License Plates Using an Artificial Neural Network

  • Kim, Hyun-Yul;Lee, Seung-Kyu;Lee, Geon-Wha;Park, Young-rok
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.7 no.4
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    • pp.212-222
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    • 2014
  • In the current study, the authors propose a method for extracting license plate regions by means of a neural network trained to output the plate's center of gravity. The method is shown to be effective. Since the learning pattern presentation positions are defined by random numbers, a different pattern is submitted to the neural network for learning each time, which enables it to form a neural network with high universality of coverage. The article discusses issues of the optimal learning surface for a license plate covered by the learning pattern, the effect of suppression learning of the number and pattern enlargement/reduction and of concentration value conversion. Results of evaluation tests based on pictures of 595 vehicles taken at an under-ground parking garage demonstrated detection rates of 98.5%, 98.7%, and 100%, respectively.

Two Layer Multiquadric-Biharmonic Artificial Neural Network for Area Quasigeoid Surface Approximation with GPS-Levelling Data

  • Deng, Xingsheng;Wang, Xinzhou
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.101-106
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    • 2006
  • The geoidal undulations are needed for determining the orthometric heights from the Global Positioning System GPS-derived ellipsoidal heights. There are several methods for geoidal undulation determination. The paper presents a method employing a simple architecture Two Layer Multiquadric-Biharmonic Artificial Neural Network (TLMB-ANN) to approximate an area of 4200 square kilometres quasigeoid surface with GPS-levelling data. Hardy’s Multiquadric-Biharmonic functions is used as the hidden layer neurons’ activation function and Levenberg-Marquardt algorithm is used to train the artificial neural network. In numerical examples five surfaces were compared: the gravimetric geometry hybrid quasigeoid, Support Vector Machine (SVM) model, Hybrid Fuzzy Neural Network (HFNN) model, Traditional Three Layer Artificial Neural Network (ANN) with tanh activation function and TLMB-ANN surface approximation. The effectiveness of TLMB-ANN surface approximation depends on the number of control points. If the number of well-distributed control points is sufficiently large, the results are similar with those obtained by gravity and geometry hybrid method. Importantly, TLMB-ANN surface approximation model possesses good extrapolation performance with high precision.

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Meridian Sinews and Sagittal Spinal Balance (경근(經筋)과 인체 시상균형에 관한 소고(小考))

  • Nam, Tong-Hyun;Shin, Sang-Hun
    • The Journal of the Society of Korean Medicine Diagnostics
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    • v.13 no.2
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    • pp.129-139
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    • 2009
  • Sagittal spinal balance means standing postural balance at sagittal plane. Postural imbalance with displacement of the patient's center of gravity can cause chronic back pain and ambulatory difficulty. The sagittal spinal balance is determined based on the deviation of the C7 plumb line, originating at the middle of the C7 vertebral body, from the posterior superior endplate of S1. The line is called as sagittal vertical axis (SVA). In the traditional Korean medicine, the meridian sinews, which are the most superficial pathways of the meridian system, associated with movement, muscle balance and defense. They too are separate from the main meridians, though they intersect the main meridians. Some creative and pioneer researchers in Korea thought that the anatomy trains, which suggested by Myers is a concept familiar to the meridian sinews. A reciprocal relationship between the superficial back line and the superficial front line used to be compared to the rigging of a sailboat. Therefore, We suggest that spine may be compared to a mast of the sailboat and that the sagittal spinal balance can be maintained with systemic reciprocal interacts between the front line muscles and the back.

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Microstructure and Tensile Properties of $SiC_p$-reinforced Aluminum Alloy Composites Fabricated by Die Casting Method (다이캐스팅법에 의해 제조된 SiC 입자강화 알루미늄합금기 복합재료의 미세조직 및 인장특성)

  • Lee, Tae-Won;Lee, Chi-Hwan
    • Journal of Korea Foundry Society
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    • v.17 no.4
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    • pp.385-392
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    • 1997
  • The main objective of this study is to investigate the microstructure and tensile strength of $SiC_p$/Al alloy composites fabricated by die casting method. Die casting was performed using the preheated mold at the pouring temperature range of $620{\sim}750^{\circ}C$ under the pressure of $1,039 kgf/cm^2$. The low speed and a following high injection speed were 0.4 and 2.1 m/s, respectively. The microstructure of $SiC_p$/Al alloy composites fabricated by die casting method was found to be finer than that of composites fabricated by gravity casting. Also, SiC particulates were homogeneously distributed in refined Al matrix due to rapid solidification. The tensile strength of $SiC_p$/Al alloy composites fabricated by die casting method was found to be varied with cast temperature. The maximun tensile strength of $SiC_p$(10 vol.% and 20 vol.%)/Al alloy composites showed 380 MPa at the cast temperature of $750^{\circ}C$ and 363 MPa at the cast temperature of $700^{\circ}C$, respectively.

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Real-Time Loitering Detection using Object Feature (객체 특징을 이용한 실시간 배회행위 검출)

  • Kim, Jin Su;Pan, Sung Bum
    • Smart Media Journal
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    • v.5 no.3
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    • pp.93-98
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    • 2016
  • The literal meaning of loitering is "to lingering aimlessly or as if aimless in or about a place". And most criminals show this kind of act before they actually commit crime. Therefore, detecting this kind of loitering can effectively prevent a variety of crime. In this paper, we propose a loitering-detection algorithm using the Raspberry Pi. Proposed algorithm uses an adaptive difference image to detect moving objects and morphology opening operation to enhance the accuracy of detection. The loitering- behavior is being detected by using the center of gravity of the object to see the changes of angle; and pixel movement distance to determine the height of the object. When the loitering-behavior is detected, it outputs the alarm to tell the users by using the Raspberry Pi.

IMPROVEMENT OF RIDE AND HANDLING CHARACTERISTICS USING MULTI-OBJECTIVE OPTIMIZATION TECHNIQUES

  • KIM W. Y.;KIM D. K.
    • International Journal of Automotive Technology
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    • v.6 no.2
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    • pp.141-148
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    • 2005
  • In order to reduce the time and costs of improving the performance of vehicle suspensions, the techniques for optimizing damping and air spring characteristic were proposed. A full vehicle model for a bus is constructed with a car body, front and rear suspension linkages, air springs, dampers, tires, and a steering system. An air spring and a damper are modeled with nonlinear characteristics using experimental data and a curve fitting technique. The objective function for ride quality is WRMS (Weighted RMS) of the power spectral density of the vertical acceleration at the driver's seat, middle seat and rear seat. The objective function for handling performance is the RMS (Root Mean Squares) of the roll angle, roll rate, yaw rate, and lateral acceleration at the center of gravity of a body during a lane change. The design variables are determined by damping coefficients, damping exponents and curve fitting parameters of air spring characteristic curves. The Taguchi method is used in order to investigate sensitivity of design variables. Since ride and handling performances are mutually conflicting characteristics, the validity of the developed optimum design procedure is demonstrated by comparing the trends of ride and handling performance indices with respect to the ratio of weighting factors. The global criterion method is proposed to obtain the solution of multi-objective optimization problem.

Area Extraction of License Plates Using a Artificial Neural Network (인공신경망을 이용한 번호판 영역 추출)

  • hwang, suen ki;Kim, Tae-Woo
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.1 no.3
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    • pp.105-109
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    • 2008
  • In the current study, the authors propose a method for extracting license plate regions by means of a neural network trained to output the plate.s center of gravity. The method is shown to be effective. Since the learning pattern presentation positions are defined by random numbers, a different pattern is submitted to the neural network for learning each time, which enables it to form a neural network with high universality of coverage. The article discusses issues of the optimal learning surface for a license plate covered by the learning pattern, the effect of suppression learning of the number and headlight sections, as well as the effect of learning pattern enlargement/reduction and of concentration value conversion. Results of evaluation tests based on pictures of 595 vehicles taken at an underground parking garage demonstrated detection rates of 98.5%.

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