• Title, Summary, Keyword: Back Analysis

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A Study on the Characteristics of Gait in Patients with Chronic Low Back Pain (만성요통환자의 보행특성에 관한 연구)

  • Kim, Kyoung;Ko, Joo-Yeon;Lee, Sung-Young
    • The Journal of Korean Physical Therapy
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    • v.21 no.2
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    • pp.79-85
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    • 2009
  • Purpose: This study examined the characteristics of gait in patients with chronic low back pain. Methods: The subjects were out-patients suffering from chronic low back pain at the department of physical therapy, B hospital in Seoul. Gait analysis was performed by dividing the subjects into two groups. The study and control group comprised 15 chronic low back pain patients and 14 healthy people, respectively. Gait analysis was performed using a VICON 512 Motion Analysis System to obtain the spatio-temporal and kinematic parameters. Results: First, there was a significant difference in the spatio-temporal parameters between the two groups (p<0.05). Second, the study group showed significant differences in the kinematic parameters during the stance phase (p<0.05). Third, there were significant differences in kinematic parameters in the study group during the swing phase (p<0.05). Conclusion: The gait pattern of patients with chronic low back pain is characterized by more rigid patterns. Compared to the control group, there was a decrease in the spatio-temporal parameters and kinematic parameters in patients with chronic low back pain. These findings are expected to play a role as basic data and to form a rehabilitation program for low back pain patients.

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Performance analysis of Back-to-Back converter composed of multi-pulse converter and PWM converter (다중펄스 컨버터와 PWM 컨버터로 구성된 Back-to-Back 컨버터의 계통연계 성능 분석)

  • Shim, Myong-Bo;Jeong, Jong-Kyou;Kim, Jong-Won;Han, Byung-Moon
    • Proceedings of the KIPE Conference
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    • pp.387-388
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    • 2010
  • 본 논문은 수십 MW용량의 풍력단지를 교류전력망에 연계하기 위한 다중펄스 컨버터와 PWM 컨버터로 구성된 Back-to-Back 컨버터를 제안하였다. 시뮬레이션 모델개발과 하드웨어 축소모형 실험을 통해 제안하는 Back-to-Back 컨버터의 시스템 구성 및 동작특성에 대해서 분석하고 3-레벨 24-펄스 컨버터를 영전압과 점호각을 제어할 경우와 점호각만을 제어할 경우 제어상의 장 단점과 제어성능을 비교분석하였다.

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The Geometry Prediction of Back-bead in Arc Welding

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.5
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    • pp.84-89
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    • 2007
  • This research was done on the basis of assumption that there is a relationship between welding parameters and geometry of the back-bead being a gap in arc welding. Multiple regression analysis was used as method for predicting the geometry of the back-bead. The analysis data and the verification data were used for the formation of multiple regression analysis. The method was used to perform the prediction of the back-bead.

The Classification and Analysis of Lateral Somatotype among Middle and High School Girls (중·고 여학생의 측면 체형분류 및 체형분석)

  • Lee, Hea-Ju
    • Fashion & Textile Research Journal
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    • v.4 no.1
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    • pp.71-78
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    • 2002
  • The purpose of this study was to classify body types of 800 female junior and high school students based on factor analysis, cluster analysis, and correspondence analysis of 15 photometric measurements of the subjects' lateral body lines. The results are as follows: The skeleton structure, which was represented the back bending by the photometric measurement, was already formed at age of 12 or 13, while the cervical skeleton, the size and inclination of the shoulder, and the degree of the lateral inclination of the upper body and the buttocks continued to grow by the age of 16. A factor analysis of the photometric measurement resulted in the sampling which determined the degree of the back bending, front-bust angle, and lateral view as well as the sampling whose factor represented the cervical inclination. A cluster analysis of the photometric measurement resulted in the four types of classification: Type 1, the straight type comprising 13.3% of the whole population; Type 2, the bent-forward type comprising 39.5%; Type 3, the lean-back type comprising 27.4%; and Type 4, the swayback type comprising 19.1%. Accordingly, the bent-forward type was found to be the dominant type among the four lateral body types.

A Case Study of Back-analysis Technique in Tunnelling Using Extended Bayesian Method and Relative Convergence Measurement (확장 Baysian 방법과 상대변위를 이용한 터널 역해석 기법의 적용사례연구)

  • Lee In-Mo;Choi Min-Kwang;Cho Kook-Hwan;Lee Geun-Ha;Choi Chung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.21 no.3
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    • pp.109-118
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    • 2005
  • It is a very difficult task to estimate engineering properties of the ground when designing underground structures, especially in tunnelling. Therefore, a feed-back system to combine the data measured in construction field with priorly estimated information at the design stage is necessary. In this paper, 3-dimensional back-analysis in tunnelling, to which only relative convergence is applied as input values, is carried out to estimate the optimum geotechnical parameters. For this purpose, the Extended Bayesian Method (EBM), which appropriately combines the objective information with the subjective one, is applied to optimize engineering parameters and 3-dimensional numerical analysis is carried out to predict a trend of relative convergence occurrence. The data measured from two tunnelling sites are used to verify the applicability of the proposed back-analysis technique. from the results of analysis, the proposed back-analysis technique is verified.

Numerical Investigation on Behavior of Back-to-Back Reinforced Earth Wall (Back-to-Back옹벽의 거동에 관한 수치 해석적 연구)

  • Yoo, Chung-Sik;Kim, Jae-Wang
    • Journal of the Korean Geotechnical Society
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    • v.25 no.12
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    • pp.131-142
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    • 2009
  • Geosynthetic reinforced soil walls are well recognized alternatives to conventional retaining walls due to many advantages in terms of ease of construction, economy, and aesthetics, among others. In recent years, the use of back-to-back (BTB) geosynthetic reinforced soil walls has been increasing for roadway and railway construction. However, there are insufficient studies concerning the behavior of BTB type geosynthetic reinforced soil walls. In this study a series of finite element analysis were performed for BTB walls with various wall geometry and reinforcement distribution. The results were then analyzed to relate the wall geometry and reinforcement distribution and the performance of BTB walls. Optimum reinforcement pattern was also investigated.

The Role of Feed Back Analysis in Observational Method (정보화 시공에서 Feed Back Analysis (터널, 암반사면, 지반굴착 등 Hard Material 사례중심으로))

  • 김학문
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.147-179
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    • 2002
  • The important role of observational method in geotechnical engineering are emphasized together with the direction of future development, concerning successful application of the technique on the site investigation, design and feed back at various construction stages. Case histories on the application of feed back are introduced in order to achieve the most economical and reliable construction for tunnel, rock slope and deep excavations through feed back system at design and construction stages. Also the limitations and advantages of the observational method and the role of feed back system are discussed for construction of tunnel, rock slope and deep excavation in hard ground such as layered ground conditions including weathered, soft and hard rocks.

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Thermal Stress Analysis of STS VOD Ladle according to the reinforcement of back filler (Back Filler의 보강에 따른 STS VOD 래들의 열응력 해석)

  • Lee, S.W.;Ham, K.C.;Bae, S.I.;Song, J.I.
    • Proceedings of the KSME Conference
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    • pp.310-315
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    • 2000
  • We analyzed thermal stress of the STS VOD ladle by the variation of material property of refractory, and determined the location of back filler using FE analysis. Thermal distribution of refractory of ladle between hot face and back face were decreased by the increasing the thermal conductivity, and thermal stress of refractory were decreased about 2 to 4 times with the decreasing the young's modulus coefficients. Back filler, which is constructed to absorb the thermal expansion of dolomite refractory, has relatively low thermal conductivity. Inner side of refractory of ladle maintained high temperature, but temperature of outer side of ladle decreased low. Consequently, inner expansion and outer contraction were appeared. and thermal stress were increased, so thermal stress by the construction of back filler were increased.

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The effects of high hell on back muscle fatigue (High Heel이 허리 근육 피로에 미치는 영향에 관한 연구)

  • 현수돈;김정룡
    • Journal of the Ergonomics Society of Korea
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    • v.16 no.3
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    • pp.37-48
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    • 1997
  • It is very common for women wear shoes with a high heel. It has been known that the high heel could disfigure the foot shape and cause various joint problems including back pain. However, few quantitative studies have been conducted. Therefore, in this study, the low back muscle has been investigated in order to find fatifue effect due to different heights of the heel. In particular, 0, 4, 6 and 8cm heel and two different shapes of heel have been used for an experiment. Ten healthy female subjects volunteered for the study. Isometric Trunk Exertion Frame(ITEF) and Electromyography were used to measure tha Median Frequency via Spectral analysis. The results indicated that the heel height significantly affected the local muscle fatigue of the back. After post hoc analysis, it was found that a proper heel height ougth to be lower than 5cm not to have severely fatigued back muscle after a casual walk for an hour. Such results could be applies to female industrial workers in order to prevent a cumulative trauma disorder of the back, and also to design a female dress shoes minimizing low back fatigue.

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Theoretical and Experimental Analysis of Back-Gated SOI MOSFETs and Back-Floating NVRAMs

  • Avci, Uygar;Kumar, Arvind;Tiwari, Sandip
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.4 no.1
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    • pp.18-26
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    • 2004
  • Back-gated silicon-on-insulator MOSFET -a threshold-voltage adjustable device-employs a constant back-gate potential to terminate source-drain electric fields and to provide carrier confinement in the channel. This suppresses shortchannel effects of nano-scale and of high drain biases, while allowing a means to threshold voltage control. We report here a theoretical analysis of this geometry to identify its natural length scales, and correlate the theoretical results with experimental device measurements. We also analyze experimental electrical characteristics for misaligned back-gate geometries to evaluate the influence on transport behavior from the device electrostatics due to the structure and position of the back-gate. The backgate structure also operates as a floating-gate nonvolatile memory (NVRAM) when the back-gate is floating. We summarize experimental and theoretical results that show the nano-scale scaling advantages of this structure over the traditional front floating-gate NVRAM.