• Title/Summary/Keyword: Obstacle Effect

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Large eddy simulation of turbulent flow around a wall-mounted cubic obstacle in a channel using Lagrangian dynamic SGS model (Lagrangian Dynamic Sub-grid Scale 모델에 의한 평행평판내 입방체 장애물 주위 유동에 관한 대 와동 모사)

  • Ko, Sang-Cheol;Park, Nam-Seob
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.3
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    • pp.369-375
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    • 2006
  • Large eddy simulation has been applied to simulate turbulent flow around a cubic obstacle mounted on a channel surface for a Reynolds number of 40000(based on the incoming bulk velocity and the obstacle height) using a Smagorinsky model and a Lagrangian dynamic model. In order to develop the LES to the practical engineering application, the effect of upwind scheme, turbulent sub-grid scale model were investigated. The computed velocities. turbulence quantifies, separation and reattachment length were evaluated by compared with the previous experimental results.

Effect of an Obstacle on the Bottom Surface of a Circular Cylinder on the Spin-up Flow (원통 용기 바닥의 장애물이 스핀업 유동에 미치는 영향)

  • Choi, Yoon-Hwan;Moon, Jong-Choon;Suh, Yong-Kweon
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.676-681
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    • 2001
  • In this paper, the spin-up from rest to a state of solid-body rotation in a circular container with a slender rectangular obstacle on the bottom wall is analysed experimentally. We use a PIV method for the evolution of the free-surface flow. Laboratory experiments have been carried out for a variety of the obstacle height h(0, 5, 10 [mm]) and the liquid depth H(25, 50, 75, 100 [mm]). It was found that the spin-up time is crucially dependent on the obstacle height T. In the case of T=10[mm] the spin-up time is considerably shorter then the other cases.

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A Study on Effects of Balance Taping Therapy applied on the patients with Arthritis caused upon the Pain in Legs and Obstacle in Daily Activity (밸런스테이핑이 퇴행성관절염 환자의 다리통증과 일상 활동장애에 미치는 효과)

  • Hyun, Sin-Sook;Park, Kyung-Sook
    • Korean Journal of Adult Nursing
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    • v.16 no.4
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    • pp.585-596
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    • 2004
  • Purpose: This study is to examine the effect of balance taping therapy applied on the old people who suffer from arthritis upon the pain in legs and obstacle in daily activity. Methods: The research period was from Dec. 2003 to Feb. 2004, and among the old female people who visited one of the welfare halls in Seoul downtown and 4 assembly hall for old people who aged over 60 years. 30 of the experimental group and 33 of control group were optionally collected. Results: The pain degree in legs and the uneasiness degree of the obstacle in the daily life of the experimental group who were treated by the balance taping was decreased than those of the control group(p=0.015, p=0.000). Conclusions: Based upon the above result, it was confirmed that the balance taping therapy has influence in decreasing the degree of the uneasiness in the leg pain and daily activity obstacle of the old people who suffer from the arthritis, and therefore it is thought that this therapy can be usefully applied for one of the nursing methods for the old patients, and besides the repeated future researches are needed.

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Obstacle Avoidance Using Velocity Dipole Field Method

  • Munasinghe, Sudath R.;Oh, Chang-Mok;Lee, Ju-Jang;Khatib, Oussama
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1657-1661
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    • 2005
  • The velocity dipole field method is presented for real-time collision avoidance of mobile robots. The direction of motion of the obstacle is used as the axis of the dipole field, and the speed of the obstacle is used to proportionally strengthen the dipole field. The elliptical field lines of the dipole field are useful to skillfully guide the robot around obstacles, quite similar to the way humans avoid moving obstacles. Field modulation coefficient is also introduced to weaken the field effect as the obstacle recedes. The real-time algorithm of the velocity dipole field has been devised and experimentally tested on the robot soccer test-bed. The results show the capability of the new real-time collision avoidance strategy and how it can overcome the weaknesses in the conventional potential field method. The new method makes an explicit and proactive action of collision avoidance, unlike the conventional method, which forces the robot merely away from the obstacle aimlessly. The proposed method delivers greater capability with no considerable computational overhead

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The Study of Plantar Foot Pressure Distribution during Obstacle Crossing with Different Height in Normal Young Adults (보행 시 장애물 높이에 따른 정상 성인의 족저압 분포 연구)

  • Han, Jin-Tae;Lee, Myung-Hee;Kim, Kyoung
    • Korean Journal of Applied Biomechanics
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    • v.18 no.2
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    • pp.1-9
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    • 2008
  • The purpose of this study was to investigate the effect of different obstacle heights on the plantar foot pressure during obstacle crossing. Sixteen healthy adults who had no musculoskeletal disorders were instructed to perform unobstructed level walking and to step over obstacles corto 10cm, 20cm, 30cm. Plantar foot forces and pressures were recorded by the Footmat system(Tekscan, Boston, USA) during level and obstacle walking with barefoot. Plantar foot surface was defined as seven regions for pressure measurement; two toe regions, three forefoot regions, one midfoot region, one heel region. One-way ANOVA was used to compare each region data of foot according to various heights. The results indicated that there are significant differences on peak pressure and maximal forces regarding each region at stance phase. As height of obstacle became high, the pathway of COP had a tendency to be short and abducted. Plantar pressure of foot could be changed by obstacle height and these findings demonstrated that obstacle with different height have an effect on structure and function of the foot.

A Study on Factors Affecting Public Health Center Workforce for Health Behavior based on Pender's Health Promotion Model (서울지역 일부 보건소 공무원의 지각된 건강상태와 건강행동과의 관련성 -Pender의 건강증진모델을 이용하여-)

  • Lee, Eun-Jeoung;Lee, Myung-Sun
    • The Journal of Korean Society for School & Community Health Education
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    • v.15 no.1
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    • pp.121-140
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    • 2014
  • Objectives: Recently, the rate of death by chronic disease, is increasing steadily. To prevent this, the public health center will have taken a leading role in the local community medical business through an establish to the national health promotion act and an amendment to the law of public health center in Korea. Results: Accordingly this research, using the Pender's health promotion model which is related with subject health behavior who government employees serve at the public health center have taken important position in the local community health promotion, have comprehended the actual condition of health behavior. For increasing the health behavior practice of subject to comprehend the factor which have effect on health behavior practice, which can be a correct role model in the local community health promotion. A survey was performed on 406 government employees who serve at five public health centers in Seoul. The period of survey was from 25th October, 2010 to 15th November, 2010. The results of this study were summarized as below. 1. Work-related stress, perceptible beneficial obstacle, and self-efficacy were composed by 5 points measure. The results show those work-related stress were $3.06{\pm}0.469$, 74perceptible beneficial obstacle were $3.74{\pm}0.471$, and self-efficacy were $3.49{\pm}0.469$. 2. As for the health behavior by general characteristic, the results have specific differences on age, education level, state of marriage, rank of the position, field of the occupation and employment forms in statics analysis. 3. As for the past health behavior by health behavior characteristic, work-related stress have specific differences on the past frequency of drinking (p<.05) in statics analysis, perceptible beneficial obstacle have specific differences on the past frequency of having breakfast(p<.05), having snacks(p<.05) and doing exercise(p<.05) in statics analysis. Self-efficacy have specific difference on the past frequency drinking(p<.01) in statics analysis. 4. According to the correlation between the factors related with health behavior and health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). Work-related stress and self-efficacy don't have specific relation in health behavior practice. 5. The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations. The ability of explanation occupied 54.8% what explained of the health behavior practice by general characteristic, perceptible health condition, employment forms and perceptible beneficial obstacle. Conclusions: According to the correlation between the factors related with health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations.

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Near-field Performance Analysis of LW-TLM Antenna for propagation obstacle (장파대역 TLM 안테나의 전파 장애물에 의한 근거리장 성능 분석)

  • Kim, Young-Wan
    • Journal of IKEEE
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    • v.24 no.4
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    • pp.1064-1068
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    • 2020
  • For LW-TLM antenna of 65 kHz, Near-field propagation characteristics due to wave propagation obstacle are analyzed in this paper. The simulation modeling for propagation effects are based on the model of actual LW-TLM antenna which utilizes the frequency of 65 kHz, and the model expressed as propagation obstacle at a mountain height and a proximity of antenna and mountain. The near-field performance are analyzed based on the parameters of simulation model. In case of a normal mountain height and distance between the adjacent mountain and antenna site, a field strength change of about 1.7 dB has occurred. Above the constant distance of propagation obstacle and antenna, the wave propagation characteristics of disregarding the effects of propagation obstacle are shown. The results of this paper can be used to design and build a transmitting antenna site with 65 kHz operating frequency.

The effects of different factors on obstacle strength of irradiation defects: An atomistic study

  • Pan-dong Lin;Jun-feng Nie;Yu-peng Lu;Gui-yong Xiao;Guo-chao Gu;Wen-dong Cui;Lei He
    • Nuclear Engineering and Technology
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    • v.56 no.6
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    • pp.2282-2291
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    • 2024
  • In this work we study the effects of different factors of dislocation loop on its obstacle strength when interacting with an edge dislocation. At first, the interaction model for dislocation and dislocation loop is established and the full and partial absorption mechanism is obtained. Then, the effect of temperature, size and burgers vector of dislocation loop are investigated. The relation between the obstacle strength and irradiation dose has been established, which bridges the irradiation source and microscale properties. Except that, the obstacle strength of C, Cr, Ni, Mn, Mo and P decorated dislocation loop is studied. Results show that the obstacle strength for dislocation loop decorated by alloy element decreases in the sequence of Cr, Ni, Mn, C, P and Mo, which could be used to help parameterize and validate crystal plasticity finite element model and therein integrated constitutive laws to enable accounting for irradiation-induced chemical segregation effects.

The effect of obstacle gait training on balance, gait and ADL of the stroke patient - pilot study (장애물 보행훈련이 뇌졸중 환자의 균형, 보행 및 일상생활활동에 미치는 영향 - 예비연구)

  • Kim, Soo Jin;Oh, Gku Bin;Lee, Hyo Jeong
    • Journal of Korean Physical Therapy Science
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    • v.27 no.2
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    • pp.1-12
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    • 2020
  • Background: The purpose of this study is intended to evaluate the effectiveness and analyse the change on balance, gait and ADL of the stroke patient by obstacle gait training. Design: Randomized controlled trial. Methods: Ten subjects with stroke patient are recruited from C rehablitation hospital located Chungbuck. The subjects which are divided to 2 group as experimental group (N=5) conducted the obstacle gait training and control group (N=5) conducted the general gait training. The gait (10mWT), balance (BBS) and ADL (FIM) were measured before and after intervention. Results: There were no significant differences (p>.05) in sex, age, height, weight and K-MMSE among subjects. There were significant differences (p<.05) in balance and gait between of the experimental group and control group. But there was no significant difference (p>.05) in the ADL between of the experimental group and control group. There were significant differences (p<.05) gait and balance in the experimental group. But there were no significant difference (p>.05) gait, balance and ADL in the control group. Conclusion: Obstacle gait training showed positive effects on the gait, balance of the stroke patient.

Improvement of Obstruction Detecting Method at Railroad Crossing by Image Analyze (영상해석을 통한 철도건널목 장애물 검지방법 개선)

  • Song, Hyeon-Sam;Kim, Young-Dal;Lee, Dae-Dong;Shim, Jae-Myung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.7
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    • pp.1444-1450
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    • 2011
  • An analysis of the causes of railroad crossing accidents reveals that most train collision accidents that occur when safety crossing devices are functioning normally occur because vehicles either experience engine failure on the tracks or because drivers were not notified of the coming train, in which case they get trapped on the tracks when the crossing barriers descend. To prevent such an accident, obstacle detection device by using laser beams detecting the presence of obstacle and crossing bar direction controller by moving direction detection sensor using the Earth's magnetic field detection technology are used in the railroad crossing. Despite using the obstacles detector and crossing bar direction controller in the railroad crossing, the equipments for the railroad crossing does not prevent accidents completely. Therefore, this research has studied new method that can detect obstacles through image analyze and alternate existing equipments. There will be excellent effect to be preventing railroad crossing accident by developing a reliable and new obstacle detecting device.