• Title/Summary/Keyword: back analysis method

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Discrimination of Lateral Torso Types by Posture for Older Women (노년 여성의 몸통 측면 자세에 따른 체형 판별)

  • Sunmi Park;Hyunsook Han
    • Fashion & Textile Research Journal
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    • v.26 no.1
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    • pp.35-43
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    • 2024
  • This study aimed to objectively classify the lateral torso posture types and functions of older women. We used 3D body scan data of 119 women aged 70-85 years from the 6th SizeKorea project. First, we defined three torso axes to represent the lateral torso posture types: posterior waist-back, back-cervical, and whole torso axes. Next, we asked experts to select one of four lateral torso posture types-stooped, straight, leaning back, and swayback postures-by looking at the lateral photographic data of 119 older women. To identify the axis that best represented each lateral torso posture type, a discriminant analysis was conducted using the angle of each of the three torso axes as an independent variable and an expert's visual classification as a dependent variable. Based on the analysis, the whole torso and backcervical axis angles were selected as variables for judging lateral torso posture types. Subsequently, we developed a classification function to determine which of the four lateral torso posture types of a particular participant was applicable for a new individual. The method developed in this study is significant in that it enables the objective classification of the lateral torso postures types of older women.

Optimum Tire Contour Design Using Systematic STOM and Neural Network

  • Cho, Jin-Rae;Jeong, Hyun-Sung;Yoo, Wan-Suk;Shin, Sung-Woo
    • Journal of Mechanical Science and Technology
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    • v.18 no.8
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    • pp.1327-1337
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    • 2004
  • An efficient multi-objective optimization method is presented making use of neural network and a systematic satisficing trade-off method (STOM), in order to simultaneously improve both maneuverability and durability of tire. Objective functions are defined as follows: the sidewall-carcass tension distribution for the former performance while the belt-edge strain energy density for the latter. A back-propagation neural network model approximates the objective functions to reduce the total CPU time required for the sensitivity analysis using finite difference scheme. The satisficing trade-off process between the objective functions showing the remarkably conflicting trends each other is systematically carried out according to our aspiration-level adjustment procedure. The optimization procedure presented is illustrated through the optimum design simulation of a representative automobile tire. The assessment of its numerical merit as well as the optimization results is also presented.

Comparison of Different Schemes for Speed Sensorless Control of Induction Motor Drives by Neural Network (유도전동기의 속도 센서리스 제어를 위한 신경회로망 알고리즘의 추정 특성 비교)

  • 이경훈;국윤상;김윤호;최원범
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.526-530
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    • 1999
  • This paper presents a newly developed speed sensorless drive using Neural Network algorithm. Neural Network algorithm can be divided into three categories. In the first one, a Back Propagation-based NN algorithm is well-known to gradient descent method. In the second scheme, a Extended Kalman Filter-based NN algorithm has just the time varying learning rate. In the last scheme, a Recursive Least Square-based NN algorithm is faster and more stable than the classical back-propagation algorithm for training multilayer perceptrons. The number of iterations required to converge and the mean-squared error between the desired and actual outputs is compared with respect to each method. The theoretical analysis and experimental results are discussed.

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A Sensorless PMSM Control Using the Separation of Two Voltage Source (이중전압원 분리를 이용한 PMSM의 센서리스 제어)

  • Jin-Woo Ahn;Sung-Jun Park;Dong-Hee Lee
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.1
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    • pp.1-7
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    • 2004
  • This paper presents a sensorless control strategy of a PMSM(Permanent Magnet Sycchoronous Motor). This method is very simple to compute the position angle of a rotor. A principle and a practical solution are described. A sensorless control algorithm is proposed to remove a mechanical position sensor. The theory is based on the superposition principle. The state equation of a motor is divided into two conditions: one is the state equation of exciting voltage and phase current in a constraint, the other is the state equation of back EMF(Electromotive Force) and phase current in a short circuit. Based on the analysis, short circuit current by back EMF is computed and then the information of position angle is calculated. The proposed method is verified by experimental results.

Performance Variation with Switching Position of 2-Phase BLDC Motor (스위칭 위치에 따른 2상 BLDC 모터의 특성변화)

  • Chang, Hong-Soon;Baek, Soo-Hyeon;Chung, Jung-Ki;Rhyu, Se-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.10
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    • pp.646-651
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    • 2000
  • Recently, the 2-phase brushless DC motor has been used in electric home appliance for low price and low energy consumption. In this paper, we analyzed a 2-phase BLDC motor using time-step finite element method. And the validity of analysis is confirmed by measuring the flux distribution on the surface of permanent magnet and back-EMF. As well, we have calculated the dynamic characteristics of target motor considering the Hall sensor position. So, we have found the optimum switching position, and improved performance of 2-phase BLDC motor.

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Analysis of Skirt Block Patterns Developed through Draping and Drafting Methods Using the Dress Form Representing the Body Features of Korean Female Fashion Models (국내 여성 패션모델 체형 반영 인대를 활용한 입체재단 및 평면재단 스커트 원형 특성 분석)

  • Park, Gin Ah
    • Journal of Fashion Business
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    • v.22 no.4
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    • pp.30-46
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    • 2018
  • The purpose of the study was to suggest certain measurements of the skirt block pattern drafting process for the Korean female fashion models, with the aim to improve its fit. For this purpose, the study carried out an analysis of the lower body features of a dress form developed for the study. This form was representative of Korean female fashion models' body features. The study performed a cross-sectional analysis at waist and hip levels and measured the angles from the frontal and lateral silhouettes of the dress forms. The comparisons of the skirt block patterns developed through draping by the use of 2 types of the dress forms developed and existed and through drafting according to the current patternmaking method have led to noticeable findings in terms of implementation of the skirt block drafting process for the Korean female fashion models. The results of the study are as follows: (1) the vertical lengths between the levels at the front waist point and the side waist point in the patterns are 0.7cm; (2) the vertical length between the levels at the front waist point and the back waist point in the back panel is 0.7cm; (3) the horizontal lengths between the perpendicular line from the side hip point and the side waist point in patterns are within a range of 2.0 to 2.2cm; (4) the horizontal length between the original and the adjusted back waist points moved into the waist line, in a range of 0.0 to 1.0cm, differs whether the center back line would be folded or sewn.

Ground Behavior Behind Soil Nailed Wall by Feed Back Analysis (역해석에 의한 쏘일네일링 벽체 배면지반의 거동 연구)

  • Jeon, Seong-Kon
    • Journal of the Korean Geotechnical Society
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    • v.19 no.3
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    • pp.5-13
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    • 2003
  • The soil nailing is one of the useful support-system in urban excavation because of the presence of other structures in the vicinity Since the soil nailing system was introduced, model experiments and theoretical studies have been performed to investigate behavior of soil nailed wall. However, there are few data in the case of multi-layered soil strata just like Seoul Metropolitan area in Korea. The feed back analyses are carried out using the measured wall displacement data for soil nailing construction sites with multi-layered strata in order to analyze the distance and the coefficients of extension zone of ground behind soil nailed wall. As a result, the distance of extension zone increased with increasing of the final excavation depth and the ratio of the distance to the final excavation depth was shown to be about 94% of the final excavation depth. Also, the coefficients of extension zone increased with enlargement of soil layer thickness and converged into constant value of 1.05. On the other hand, the maximum vertical displacements by the feed back analysis and Caspe's method were shown to be approximately 80%, 150~280% of the maximum horizontal displacement respectively.

Three-Dimensional Thermohydrodynamic Analysis of Journal Bearings Operating in Turbulent Region Using $kappa-varepsilon$ Model (난류상태로 운전되는 저어널베어링에서의 $kappa-varepsilon$ 모델을 이용한 3-차원 THD해석)

  • 이득우;김경웅
    • Tribology and Lubricants
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    • v.3 no.1
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    • pp.39-46
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    • 1987
  • Frictional loss in turbulent regime is abnormally increased compared with in laminar regime. Thus the consideration of temperature rise across fluid film is significant in analysis and conventional isothermal theory loses its usefulness for performance prediction. This paper proposes to the three-dimensional thermohydrodynamic analysis of finite journal bearings operating under turbulent condition using two-equation model($\kappa-\varepsilon$ model) proposed by Hassid & Poreh. The equations are solved numerically by finite difference method. We make the analysis applicable even at large eccentricity when back flow of the lubricants occurs and axial flow is no longer ignored compared to circumferential flow.

The Clinical Study on the Effects of Moxibustion to FBSS(Failed Back Surgery Syndrome) (요추 수술실패증후군 환자에 대한 구법(灸法)의 임상적 연구)

  • Lee, Dong-Hwa;Park, Hee-Soo;Hwang, Jung-Su
    • Journal of Acupuncture Research
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    • v.23 no.3
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    • pp.67-75
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    • 2006
  • Objectives : The purpose of this study is to evaluate the clinical effect of moxibustion treatment for FBSS patients by VAS. Methods : This clinical study was carried out for 51 cases with FBSS, who had been treated from January, 2003 to October, 2005, in oriental medical clinic. The patients were treated by the moxibustion during 8 weeks on the pain region of lower back or legs. We measured the effects of treatment by VAS. SPSS( Statistical Program for Social Science) for Windows was used for statistical analysis and repeated measures ANOVA was performed to gauge the improvement of VAS. Results : 1. We investigated 25 female and 26 male patients. The age distribution was from early 20's to 70's, among which 50's were most common. 2. The worsening factors are usually overwork and heavy lifting, but the main reason is unknown. 3. According to VAS, The patients with FBSS were improved by moxibustion treatment. Conclusion : Through this research, moxibustion therapy is considered to be effective and safe method for FBSS(Failed Back Surgery Syndrome). Moxibustion treatment had some problems that should be overcome such as severe pain and burning. Therefore we should pay more attention.

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Output Characteristic Comparison of BLDC Motor for Water Circulation System According to Sensorless Control Methods (물 순환 시스템용 BLDCM의 센서리스 제어 방식에 따른 출력 특성 비교)

  • Kim, Sung-An;Cho, Yun-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.9
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    • pp.1325-1333
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    • 2017
  • The sensorless control of blushless DC motor(BLDCM) is based on the $120^{\circ}$ control in which the back electromotive force(Back EMF) for estimating the position of the rotor can be detected. However, the $120^{\circ}$ control has a disadvantage that the torque constant is small as compared with $180^{\circ}$ control which can not detect the back EMF. The $150^{\circ}$ control which complements these problems makes it possible to detect the back EMF and improve the torque constant by 12.5% compared to the $120^{\circ}$ control. Therefore, this paper compares the output characteristics of BLDCM through finite element method analysis (FEA) by the conventional and proposed control methods of BLDCM for water circulation system and proposes design for downsizing and weight reduction of BLDCM according to secured torque constant. The validity of the proposed control and design proposal is proved through simulation and experimental results by comparing the output characteristics of $120^{\circ}$ control and $150^{\circ}$ control.