• Title/Summary/Keyword: Dimensional analysis

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Change of Lumbar Spine and Hip Joint Flexion Angles During Forward Bending of the Trunk Using Manual Facilitation and a Stick (도수 촉진과 막대를 이용한 몸통의 전방 굴곡 운동에 따른 요추와 고관절 굴곡 각도의 변화)

  • Choung, Sung-Dae;Park, Kyue-Nam;Hong, Ji-A;Cho, Min-Sue;Son, Dong-Hwi;Cynn, Heon-Seock
    • Physical Therapy Korea
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    • v.18 no.1
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    • pp.57-63
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    • 2011
  • The purpose of this study was to identify the effects of manual facilitation and a stick on lumbar and hip joint flexion angles in subject with lumbar flexion syndrome during forward bending from a sitting position. Fifteen subjects with lumbar flexion syndrome were recruited for this study. As a pretest, all subjects performed three repetitions of bending the trunk forward until the tips of their fingers touched the target bar. After this pretest, the subjects practiced the forward bending of the trunk 10 times, using either manual facilitation or a stick. Then, as a posttest, all subjects repeated the pretest procedure. The flexion angles of lumbar spine and hip joint during forward bending in a sitting position were measured using a three-dimensional motion analysis system. A paired t-test was used to determine the statistical differences between pre-test and post-test flexion angles and pre- and post-test flexion angle differences between forward bending with manual facilitation and forward bending with a stick. The level of statistical significance was set at p=.05. The results of the study showed that the angle of the lumbar flexion decreased significantly and the bilateral hip flexion angle increased significantly when performing forward bending with stick and manual facilitation. Furthermore, the angle of lumbar flexion decreased significantly and the angle of bilateral hip flexion increased significantly in forward bending with a stick compared to forward bending with manual facilitation. The findings of this study indicate that both forward bending with manual facilitation and sticks could be used to prevent excessive lumbar flexion and increase hip flexion, and that forward bending with a stick is more effective than forward bending with manual facilitation for inducing lumbar spine and hip joint angle changes.

Effect of Partial Prestressing Ratio and Effective Prestress on the Flexural Behavior of Prestressed Lightweight Concrete Beams (프리스트레스트 경량 콘크리트 보의 휨 거동에 대한 부분 프리스트레싱비와 유효 프리스트레스의 영향)

  • Yang, Keun-Hyeok;Moon, Ju-Hyun;Byun, Hang-Yong
    • Journal of the Korea Concrete Institute
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    • v.23 no.1
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    • pp.39-48
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    • 2011
  • The present investigation evaluates the flexural behavior of pre-tensioned lightweight concrete beams under two-point symmetrical concentrated loads according to the variation of the partial prestressing ratio and the effective prestress of prestressing strands. The designed compressive strength of the lightweight concrete with a dry density of 1,770 $kg/m^3$ was 35 MPa. The deformed bar with a yield strength of 383 MPa and three-wire mono-strands with tensile strength of 2,040 MPa were used for longitudinal tensile reinforcement and prestressing steel reinforcement, respectively. According to the test results, the flexural capacity of pre-tensioned lightweight concrete beams increased with the increase of the partial prestressing ratio and was marginally influenced by the effective prestress of strands. With the same reinforcing index, the normalized flexural capacity of pre-tensioned lightweight concrete beams was similar to that of pre-tensioned normal-weight concrete beams tested by Harajli and Naaman and Bennett. On the other hand, the displacement ductility ratio of pre-tensioned lightweight concrete beams increased with the decrease of the partial prestressing ratio and with the increase of the effective prestress of strands. The load-displacement relationship of pre-tensioned lightweight concrete beam specimens can be suitably predicted by the developed non-linear two-dimensional analysis procedure. In addition, the flexural cracking moment and flexural capacity of pre-tensioned lightweight concrete beams can be conservatively evaluated using the elasticity theorem and the approach specified in ACI 318-08, respectively.

The Analysis of Mesoscale Circulations Characteristics Caused by the Evaporation-Efficiency of Water Retention Pavement (보수성 도로 포장재의 증발효율 변화에 의한 중규모 순환장 특성 분석)

  • Kim, In-Su;Lee, Soon-Hwan;Kim, Hae-Dong;Suh, Young-Chan
    • Journal of the Korean earth science society
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    • v.30 no.6
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    • pp.709-720
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    • 2009
  • Field observation and numerical experiments were conducted to understand the impact of water retention pavement on the surface heat budget and on the regional circulation. The numerical model applied in this study is the atmospheric dynamic model Local Circulation Model (LCM) with two dimensional grid system, and a field observation was carried out under the clear sky and calm conditions of the weather on 19 July 2007. In the field observation, the maximum value of surface temperature on pavement covered with water retention material reached the $41.2^{\circ}C$ at 1430 LST and the values was lower for $16.1^{\circ}C$ than that of asphalt without the material. The Case BET03 assumed to be 0.3 for the surface evaporation efficiency was in good agreement with the observation and its sensible and latent heat fluxes were numerically estimated to be 229 and 227 $W/m^2$, respectively. Results of the numerical experiments demonstrated that the water retention pavement tends to induce the increase of latent heat flux associated with the lower surface temperature and mixing height during the daytime. Discontinuity of latent heat caused by the water retention pavement also tends to promote the development of mesoscale circulation called as land-land breeze or country breeze.

A Study on the Estimation of Calcaneal Width Using a Correlation of Calcaneal Length and Width (종골 길이와 너비의 상관관계를 이용한 종골 너비 추정에 관한 연구)

  • Chun, Dong-il;Hwang, Shu Chiang;Cho, Jae-ho;Choi, Sung-Woo;Kim, Yong Beom;Won, Sung Hun
    • Journal of Korean Foot and Ankle Society
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    • v.21 no.2
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    • pp.61-65
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    • 2017
  • Purpose: The purpose of this study was to determine the correlation and ratio between the calcaneal length and width for predicting the width of calcaneus. Materials and Methods: A total of 190 feet (190 patients) were included based on computed tomography scans. The length of calcaneus (CL) was measured on the line connecting the center of a circle tangent to the cortical margin in the anterior and posterior parts of the calcaneus in a sagittal plane (W1, W2). The width of the calcaneus was defined as the horizontal line of each part (W1, W2, W3) on the same axial plane. The relationship between the measurement was determined through a correlation analysis. The reliability was assessed based on intraclass correlation coefficients. Results: The CL and widths of calcaneus (W1, W2, W3) had a good positive correlation (r=0.848 [W1/CL], r=0.738 [W2/CL], r=0.769 [W3/CL]; p<0.001). The mean CL and widths ratios were 0.33 (W1/CL), 0.37 (W2/CL), and 0.37 (W3/CL). Using these ratios to estimate the widths by multiplying each ratio by the measured calcaneal length, we found a difference between the estimated calcaneal widths and the actual measured calcaneal widths values was 0.25 mm, 0.43 mm, and 0.16 mm. All measurements showed good-to-excellent inter- and intraobserver reliability. Conclusion: This study analyzed the correlation and ratio between the length and width of the calcaneus. The results will help orthopedic surgeons fixate screws in a stable manner to prevent iatrogenic injuries to the medial neurovascular structures of the calcaneus.

A photoelastic evaluation of stress distribution during distal movement of upper molar (헤드기어를 이용한 상악 제1대구치의 후방이동 시 응력분포에 관한 광탄성법적 연구)

  • Song, Sae-Eun;Lim, Sung-Hoon;Yoon, Young-Joon;Kim, Kwang-Won
    • The korean journal of orthodontics
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    • v.34 no.2 s.103
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    • pp.121-129
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    • 2004
  • The purpose of this study was to photoelastically visualize 4he distribution of fortes transmitted to the alveolus and surrounding structures using three different types of headgear for the distal movement of the upper molars. A photoelastic maxillary model was made and three different directional forces applied, which were high-pull, straight-pull, and cervical-pull. Stress distribution was recorded through circular polariscope, and two-dimensional photoelastic stress analysis was performed according to isochromatic fringe characteristics. The results were as follows: 1. In the case of high-pull headgear bodily movement occurred in the medium- length outer bow, stress distribution in the apical region was 1st molar, 2nd premolar, lst premolar in sequence and there was no apparent difference. 2. In the case of straight-pull headgear, bodily movement occurred in the long outer bow and stress distribution in the apical region was heavy in the 1st molar, 2nd premolar, 1st premolar in sequence. But. there were no apparent differences according to the length of the outer bow. 3. In the case of cervical- pull headgear, bodily movement also occulted in 4he long outer bow, and apical stress of the premolar region was heaviest among other cases and apical stress of the 2nd premolar was heaviest in the short outer bow. In clinical situations, to achieve bodily movement of the upper 1st molars without modifying outer bow height, applying an outer bow length as long as the inner bow length in high-pull headgear and applying an outer bow length longer than the inner bow length in straight-pull, cervical-pull headgear are recommended.

Development of Tomographic SASW Method to Evaluate Two-Dimensional Variability of Shear Stiffness (지반 및 구조물의 이차원적 전단강성 평가를 위한 토모그래픽 SASW 기법의 개발)

  • 조성호
    • Journal of the Korean Geotechnical Society
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    • v.15 no.2
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    • pp.29-42
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    • 1999
  • The SASW (Spectral-Analysis-of-Surface-Waves) method, which evaluates the stiffness structure of the subsurface and structures nonintrusively and nondestructively, has been successfully used in the civil engineering applications. However, the SASW method assumes that the subsurface or structures consist of horizontal multi-layers, so that the method has some difficulty in continuously evaluating the integrity of a tunnel lining and a pavement system. This difficulty prevents the SASW method from being used to generate a tomographic image of stiffness for the subsurface or structures. Recently, the GPR technique which has the advantage of continuously evaluating integrity of the subsurface and structures has been popular. This advantage of GPR technique initiated the efforts to make the SASW method, which is superior to GPR and other nondestructive testing methods due to its capability of evaluating stiffness and modulus, be able to do continuous evaluation of stiffness structure, and the efforts finally lead to the development of \ulcornerTomographic SASW Technique.\ulcorner Tomographic SASW technique is a variation of the SASW method, and can generate a tomographic image of stiffness structure along the measurement line. The tomographic SASW technique was applied to the investigation of lateral variability of a sand box placed by the raining method for the purpose of verifying its effectiveness. Tomographic SASW measurements on the sand box revealed that the investigated sand box has different shear stiffness along the measurement line, which gave a clue of how to make a better raining device.

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Numerical Study on Lateral Pile Behaviors of Piled Gravity Base Foundations for Offshore Wind Turbine (수치해석을 통한 해상풍력 말뚝지지중력식기초의 수평거동 분석)

  • Seo, Ji-Hoon;Choo, Yun Wook;Goo, Jeong-Min;Kim, Youngho;Park, Jae Hyun
    • Journal of the Korean Geotechnical Society
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    • v.32 no.11
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    • pp.5-19
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    • 2016
  • This paper presents the results from three-dimensional finite element (FE) analysis undertaken to provide insight into the lateral behaviors of piled gravity base foundation (GBF) for offshore wind turbine. The piled GBF was originally developed to support the gravity based foundation in very soft clay soil. A GBF is supported by five piles in a cross arrangement to achieve additional vertical bearing capacity. This study considered four different cases including a) single pile, b) three-by-three group pile (with nine piles), c) cross-arrangement group pile (with five piles), and d) piled GBF. All the cases were installed in homogenous soft clay soil with undrained shear strength of 20 kPa. From the numerical results, p-y curves and thus P-multiplier was back-calculated. For the group pile cases, the group effect decreased with increasing the number of piles. Interestingly, for the piled GBF, the P-multipliers showed a unique trend, compared to the group pile cases. This study concluded that the global lateral behaviour of the piled GBF was influenced strongly by the interaction between GBF and contacted soil surface.

Asymmetric Diffusion Model for Protein Spot Matching in 2-DE Image (2차원 전기영동 영상의 단백질 반점 정합을 위한 비대칭 확산 모형)

  • Choi, Kwan-Deok;Yoon, Young-Woo
    • The KIPS Transactions:PartB
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    • v.15B no.6
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    • pp.561-574
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    • 2008
  • The spot detection phase of the 2-DE image analysis program segments a gel image into spot regions by an image segmentation algorithm and fits the spot regions to a spot shape model and quantifies the spot informations for the next phases. Currently the watershed algorithm is generally used as the segmentation algorithm and there are the Gaussian model and the diffusion model for the shape model. The diffusion model is closer to real spot shapes than the Gaussian model however spots have very various shapes and especially an asymmetric formation in x-coordinate and y-coordinate. The reason for asymmetric formation of spots is known that a protein could not be diffused completely because the 2-DE could not be processed under the ideal environment usually. Accordingly we propose an asymmetric diffusion model in this paper. The asymmetric diffusion model assumes that a protein spot is diffused from a disc at initial time of diffusing process, but is diffused asymmetrically for x-axis and y-axis respectively as time goes on. In experiments we processed spot matching for 19 gel images by using three models respectively and evaluated averages of SNR for comparing three models. As averages of SNR we got 14.22dB for the Gaussian model, 20.72dB for the diffusion model and 22.85dB for the asymmetric diffusion model. By experimental results we could confirm the asymmetric diffusion model is more efficient and more adequate for spot matching than the Gaussian model and the diffusion model.

The Conceptual Study of Knowledge Adoption based on Resource and Institutionalization Theory for Organizational Knowledge Creation Applied to Knowledge Management Systems (지식 원천 이론과 제도적 이론 관점에서 조직의 지식 수용과 창출에 관한 개념적 연구)

  • Sun, Jong-Hak;Yoon, Jung-Hyeon
    • Management & Information Systems Review
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    • v.35 no.2
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    • pp.119-136
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    • 2016
  • The purpose of this study are as follows : First, This study conceptually provide an insight of reasons that organizations seek to create, acquire, store and distribute knowledge at the level of an organization and of process how they can transform or evolve to knowledge based organizations. Second, this study confirms examine what theories can be used to knowledge management, how such theories can be useful to analyse knowledge management and provide a theoretical foundation for knowledge management research. Applied to the theories of knowledge based and resource based view and institutional theory, the essence of knowledge management confirms that the organization finds job-related knowledge and know-how retained by individual of organizational members systematically and shares common knowledge within the organization and explains knowledge creation, multi-dimensional knowledge transition and share in all dimension of individual, group, and organization. As a result of comparative analysis of theory of organizational knowledge creation theory, In knowledge management, building of knowledge-creative culture, transitional process of explicit knowledge and tacit knowledge, knowledge creation and knowledge operation are important. In the basis on these study results, we discussed how the organizational knowledge creation theory can be used to manage knowledge in the organization, and also proposed hypotheses based on some arguments against the universal acceptance of the theory.

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Time-split Mixing Model for Analysis of 2D Advection-Dispersion in Open Channels (개수로에서 2차원 이송-분산 해석을 위한 시간분리 혼합 모형)

  • Jung, Youngjai;Seo, Il Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.2
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    • pp.495-506
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    • 2013
  • This study developed the Time-split Mixing Model (TMM) which can represent the pollutant mixing process on a three-dimensional open channel through constructing the conceptual model based on Taylor's assumption (1954) that the shear flow dispersion is the result of combination of shear advection and diffusion by turbulence. The developed model splits the 2-D mixing process into longitudinal mixing and transverse mixing, and it represents the 2-D advection-dispersion by the repetitive calculation of concentration separation by the vertical non-uniformity of flow velocity and then vertical mixing by turbulent diffusion sequentially. The simulation results indicated that the proposed model explains the effect of concentration overlapping by boundary walls, and the simulated concentration was in good agreement with the analytical solution of the 2-D advection-dispersion equation in Taylor period (Chatwin, 1970). The proposed model could explain the correlation between hydraulic factors and the dispersion coefficient to provide the physical insight about the dispersion behavior. The longitudinal dispersion coefficient calculated by the TMM varied with the mixing time unlike the constant value suggested by Elder (1959), whereas the transverse dispersion coefficient was similar with the coefficient evaluated by experiments of Sayre and Chang (1968), Fischer et al. (1979).