• Title/Summary/Keyword: numerical methods

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Analysis on the characteristics of the earth pressure distribution induced by the integrated steel pipe-roof construction (일체형 강관 파이프루프 시공에 따른 주변 지반의 토압 분포 특성 분석)

  • Sim, Youngjong;Jin, Kyu-Nam;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.5
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    • pp.455-468
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    • 2013
  • In recent, various types of steel pipe-roof methods, which is reinforced by mortar after propulsion of steel pipe into the ground, have been used for the construction of trenchless underpass. Integrated steel pipe-roof has flexural stiffness and can resist against overburden load and reduce the stress acting on the concrete underpass structures. Due to arching effect, vertical and horizontal stress distribution around the steel pipe-roof is changing. In this study, therefore, the characteristic of stress distribution around the underpass induced by the construction of integrated steel pipe-roof is investigated by using numerical method. To examine the soil-structure interaction, interface element is introduced. Results show that vertical stress acting on the concrete structure placing inside the steel pipe-roof is significantly reduced due to arching effect and flexural stiffness of integrated steel pipe-roof. Design load can be reduced and effective design of underpass will be available if the earth pressure reduction due to arching effect is considered in the design stage.

Two-Dimensional Magnetotelluric Interpretation by Finite-Element Method (유한요소법에 의한 MT 법의 2차원 해석)

  • Kim, Hee-Joon;Choi, Ji-Hyang;Han, Nu-Ree;Lee, Seong-Kon;Song, Yoon-Ho
    • Geophysics and Geophysical Exploration
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    • v.11 no.2
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    • pp.85-92
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    • 2008
  • Magnetotelluric (MT) methods are widely applied as an effective exploration technique to geothermal surveys. Two-dimensional (2-D) analysis is frequently used to investigate a complicated subsurface structure in a geothermal region. A 2-D finite-element method (FEM) is usually applied to the MT analysis, but we must pay attention to the accuracy of so-called auxiliary fields. Rodi (1976) proposed an algorithm of improving the accuracy of auxiliary fields, and named it as the MOM method. Because it introduces zeros into the diagonal elements of coefficient matrix of the FEM total equation, a pivoting procedure applied to the symmetrical band matrix makes the numerical solution far less efficient. The MOM method was devised mainly for the inversion analysis, in which partial derivatives of both electric and magnetic fields with respect to model parameters are required. In the case of forward modeling, however, we do not have to resort to the MOM method; there is no need of modifying the coefficient matrix, and the auxiliary fields can be elicited from the regular FEM solution. The computational efficiency of the MOM method, however, can be greatly improved through a sophisticated rearrangement of the total equation.

A New Treatment Modality Using Topical Sulfasalazine for Oral Lichen Planus (구강편평태선에 대한 sulfasalzine의 국소적용)

  • Jeong, Sung-Hee;Park, Su-Hyeon;Ok, Soo-Min;Heo, Jun-Young;Ko, Myung-Yun;Ahn, Yong-Woo
    • Journal of Oral Medicine and Pain
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    • v.37 no.3
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    • pp.155-159
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    • 2012
  • Background Oral lichen planus (OLP) is a chronic inflammatory disease characterized by cell-mediated immune responses, but the exact cause is unknown. Sulfasalazine has shown efficacy in the treatment of cutaneous lichen planus. Objective Our purpose was to assess the usefulness of sulfasalazine in treatment of OLP resistant to corticosteroid therapy. This study provides a new option for controlling OLP symptoms. Methods Two patients with the symptomatic reticular form of OLP were treated with 30 mg/5 ml of topical sulfasalazine for 8 to 15 weeks and were evaluated for symptom severity using a numerical analog scale during each week of treatment. The lesion size was measured using a 2 $mm^2$ grid. Results After 2 weeks of application, both patients reported improvements in their symptoms and lesions. Most of the lesions disappeared after 8 weeks of treatment without any side effects. Conclusion Topical sulfasalazine can be a successful treatment option for patients with oral lichen planus resistant to steroid therapy.

Efficient Prediction of Broadband Noise of a Centrifugal Fan Using U-FRPM Technique (U-FRPM 기법을 이용한 원심팬 광대역소음의 효율적 예측)

  • Heo, Seung;Cheong, Chulung
    • The Journal of the Acoustical Society of Korea
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    • v.34 no.1
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    • pp.36-45
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    • 2015
  • Recently, a lot of studies have been made about the methods used to generate turbulent velocity fields stochastically in order to effectively predict broadband flow noise. Among them, the FRPM (Fast Random Particle Mesh) method which generates turbulence with specific statistical properties using turbulence kinetic energy and dissipation obtained from the steady solution of the RANS (Reynolds Averaged Navier-Stokes) equations has been successfully applied. However, the FRPM method cannot be applied to the flow noise problems involving intrinsic unsteady characteristics such as centrifugal fan. In this paper, to effectively predict the broadband noise generated by centrifugal fan, U-FRPM (unsteady FRPM) method is developed by extending the FRPM method to be combined with the unsteady numerical solutions of the unsteady RANS equations to generate the turbulence considered as broadband noise sources. Firstly, an unsteady flow field is obtained from the unsteady RANS equations through CFD (Computational Fluid Dynamics). Then, noise sources are generated using the U-FRPM method combined with acoustic analogy. Finally, the linear propagation model which is realized through BEM (Boundary Element Method) is combined with the generated sources to predict broadband noise at the listeners' position. The proposed technique is validated to compare its prediction result with the measured data.

Chromosomal Abnormalities in Human Oocytes Fail to Fertilize after Insemination In Vitro (수정에 실패한 인간 난자에 있어서의 염색체의 수의 이상)

  • Son, Weon-Young;Lee, Kyung-Ah;Park, Sang-Hee;Han, Sei-Yul;Yoon, Tae-Ki;Jung, Hyung-Min;Kwak, In-Pyung;Cha, Kwang-Yul
    • Clinical and Experimental Reproductive Medicine
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    • v.22 no.2
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    • pp.203-210
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    • 1995
  • Many oocytes fail to fertilize and cleave in vitro and many embryos transferred back to uterus fail to implant or maintain implantation. Chromosomal abnormalities in the male and female gametes may contribute to this loss. The higher incidence of meiotic chromosomal abnormalities bas been found in oocytes than in sperm. The wide range of incidence of chromosomal abnormalities in unfertilized oocytes has been reported in human IVF program (26-63%). However, factors affecting chromosomal abnormalities are not well understood. The present study has been conducted to investigate effects of the method for ovarian hyperstimulation, women's age, and the number of oocytes retrieved per patients on the incidence of numerical chromosomal abnormalities. Five hundred eighty four unfertilized metaphase II oocytes were subjected to chromosomal analysis. Included unfertilized oocytes were from 220 patients (mean $age=32.7{\pm}3.0$) and three hundred thirty oocytes were legible for analysis. Two hundred fourty five oocytes out of 330 (73.3%) were normal, while 38 (11.5%) were hyperploidy, 35 (10.6%) were hypoploidy, and 12 (3.6%) were diploidy. Significant difference in chromosomal abnormalities was not found between two patient groups stimulated by follicular stimulating hormone/human menopausal gonadotrophin (FSH/HMG) (25.9%) and gonadotrophin-releasing hormone agonist/follicular stimulating hormone/human menopausal gonadotrophin (GnRHa/FSH/HMG) (28%). There was a tendency of increasing chromosomal abnormalities in unfertilized oocytes from older patients (<30 yrs: 20.3%, 30-34yrs: 26.9%, >34 yrs: 35.3%). The number of oocytes retrieved per patient had no effect the incidence of chromosomal abnormalities (1-5: 31. 4%, 6-10: 29.8%, 11-15: 28.6%, > 15: 16.5%). These results from the present study suggest that the chromosomal abnormalities observed in the unfertilized oocytes has not affected by the stimulation methods, patient's age, and the number of oocytes retrieved per patients.

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Numerical Approach to Investigate the Effect of Mud Pressure on the Borehole Stability during Horizontal Directional Drilling (수평굴착 시 점토압력이 굴착공의 안정에 미치는 영향에 관한 수치해석적 연구)

  • Kang, Jae Mo;Lee, Janggeun;Bae, Kyu-Jin;Moon, Changyeul;Ban, Hoki
    • Journal of the Korean Geotechnical Society
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    • v.31 no.12
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    • pp.71-76
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    • 2015
  • Recently, people are increasingly interested in horizontal directional drilling (HDD) to construct oil and gas pipeline and utility pipeline in the urban area as one of trenchless methods. One of major issues during the HDD is the collapse of borehole, which may be the potential causes of ground collapse. This study investigated the effect of mud pressure on the borehole stability, using finite element analysis. Since the borehole is being drilled with a certain angle, three dimensional analysis should be performed. The borehole stability was examined by applying two different types of mud pressures, i.e., uniform and non-uniform, to the exterior surface of borehole. The results show that the high mud pressure at the beginning of drilling, i.e., at shallow depth, causes the borehole collapse, whereas the borehole was stable even at high mud pressure as the drilling depth increases. It can be said that the determination of maximum mud pressure is strongly related to the drilling depth.

A study of quantitative correlation between step animation and emotional expressions (스텝 애니메이션과 감성 표현 사이의 정량적 상호관계에 관한 연구)

  • Lee, Ji-Sung;Jeong, Jae-Wook
    • Archives of design research
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    • v.17 no.4
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    • pp.141-148
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    • 2004
  • The purpose of this study is to define the emotion that expressed in step animation and to quantify the intuitional expression of emotion that related step for using extract, measure, analysis the stimulate element about step. The survey of relation with 27 word of emotional expressions and 36 moving pictures of step sample is used for method of this test. The emotional mental structure is transferred to 2 dimensional planes as applying the results of analysis of integrated data using Quantification Method 3, which the integrated data is composed two axial - confidential axial and stabling axial. Analysis of distribution of 2 dimensional diagram shows that the second of the plane and the third of the plane have much data. However, the first of the plane and the forth of the plane have a little data. Through this kind of analysis of graph, it is difficult to express a different emotion between unstable the timidity mind and stable feel the timidity mind using only step analysis. Six difference types about physical elements affecting to emotion are selected and analyzed such as the paces of step, the rate of step, the movement angle of pelvis, the swing range of arm, angle of backbone and the lean angle of body. The result is that the rate of stop and the lean angle of body are the major element that effects to emotional stimulate of stop. This thesis argues about methods transforming subjective expression to objective and quantitative expression with the state of delicate emotion of character apply to step animation naturally. Those data to apply to multi-contents in future are the main target in this study.

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Effectiveness of Korean Medical Treatments, Including Motion-Style-Acupuncture-Treatment Using Traction, on Inpatients with Low Back Disability: A Retrospective Chart Review (요추기능제한을 동반한 입원 환자들에게 있어서 견인보행운동요법을 포함한 통합한의치료의 유효성: 후향적 의무기록 분석)

  • Gang, Byeong-gu;Jeon, Se Hwan;Cho, Yongkyu;Lee, Keunjae;Yoon, Youngsuk;Kim, Jongho;Lee, Won Jun;Han, Subin;Kum, Chang Jun;Koh, Wonil
    • Journal of Korean Medicine Rehabilitation
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    • v.28 no.4
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    • pp.51-57
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    • 2018
  • Objectives Low back disability, along with low back pain, places a significant social burden in terms of work loss and medical expenses. Motion-Style-Acupuncture-Treatment using Traction (T-MSAT) is employed as one of the conservative treatments to such conditions. In the present study, effectiveness of Korean Medical treatments, including T-MSAT, was investigated in inpatients with low back disability and low back pain. Methods Among the patients who were admitted between January 2018 to June 2018 with disabled low back function, ones that were treated with T-MSAT were identified. Pain and function were compared at the point of admission and discharge, using Numerical Rating Scale (NRS) and Oswestry Disability Index (ODI), respectively. Results Over the hospitalization period of 34.55 days, pain intensity significantly decreased from NRS score of 6.14 to 3.26 and low back function also significantly improved from ODI score of 50.93 to 33.73 upon receiving Korean Medical treatments including T-MSAT. Conclusions Korean Medical treatments including T-MSAT were found to be effective in inpatients with low back disability with a statistical significance. To evaluate the sole effectiveness of T-MSAT, rigorous clinical trials are necessitated in future.

Identification of Voice for Listeners who Feel Favor Using Voice Analysis (음성 분석을 이용한 청자가 호감을 느끼는 목소리에 대한 규명)

  • Choi, Ji Hyun;Cho, Dong Uk;Jeong, Yeon Man
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.1
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    • pp.122-131
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    • 2016
  • In the smart societies, such as the current unlike in the past, the voice that listeners will feel favor is changing through the development of ICT technologies and infrastructure. In other words, in the past, loud, intensive and fast voice is a favorite but now a new social and cultural situation that is changing them with ICT technologies. Now, this becomes one of the important things that we clarify 'Is it a voice that feels a favor?'. For this, in this paper, we identified what voice that listeners feel favor by applying ICT technologies. Studies were carried out to proceed largely divided into two categories. Firstly, as the quantified data, we extracted the impact on favorable feeling of listeners which related with emotional speech by empirical analysis work. To do this, we performed the experiment for the public. Secondly, we identified what kind of voice which listeners feel a good impression. For this, we identified voice characteristics that there are people who are influential in the real society. Also, we extracted both the voice characteristics of each influential people and common voice characteristics. In addition, we want to overcome the problems of qualitative methods that have originally limitations in objective respects which is significant to the voice analysis. For this, we performed the experiments of the voice analysis by numerical and visual approaches.

The Response Prediction of Flexible Pavements Considering Nonlinear Pavement Foundation Behavior (비선형 포장 하부 거동을 고려한 연성 포장의 해석)

  • Kim, Min-Kwan
    • International Journal of Highway Engineering
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    • v.11 no.1
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    • pp.165-175
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    • 2009
  • With the current move towards adopting mechanistic-empirical concepts in the design of pavement structures, state-of-the-art mechanistic analysis methodologies are needed to determine accurate pavement responses, such as stress, strain, and deformation. Previous laboratory studies of pavement foundation geomaterials, i.e., unbound granular materials used in base/subbase layers and fine-grained soils of a prepared subgrade, have shown that the resilient responses followed by nonlinear, stress-dependent behavior under repeated wheel loading. This nonlinear behavior is commonly characterized by stress-dependent resilient modulus material models that need to be incorporated into finite element (FE) based mechanistic pavement analysis methods to predict more realistically predict pavement responses for a mechanistic pavement analysis. Developed user material subroutine using aforementioned resilient model with nonlinear solution technique and convergence scheme with proven performance were successfully employed in general-purpose FE program, ABAQUS. This numerical analysis was investigated in predicted critical responses and domain selection with specific mesh generation was implemented to evaluate better prediction of pavement responses. Results obtained from both axisymmetric and three-dimensional (3D) nonlinear FE analyses were compared and remarkable findings were described for nonlinear FE analysis. The UMAT subroutine performance was also validated with the instrumented full scale pavement test section study results from the Federal Aviation Administration's National Airport Pavement Test Facility (FAA's NAPTF).

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