• 제목/요약/키워드: numerical methods

검색결과 5,302건 처리시간 0.033초

추나요법을 적용한 한방복합치료로 호전된 요추 추간판 탈출증으로 인한 비구조적 척추측만증 5례: 증례보고 (Five Cases of Nonstructural Scoliosis with Lumbar Herniated Intervertebral Disc Treated by Complex Korean Medicine Treatment with Chuna Manual Therapy: Case Report)

  • 남궁진;황보경;신원빈;최효정;백혜경;이윤하;최동주
    • 척추신경추나의학회지
    • /
    • 제15권1호
    • /
    • pp.121-134
    • /
    • 2020
  • Objectives : This case report describes the management of five patients suffering from nonstructural scoliosis with lumbar herniated intervertebral disc all treated with complex Korean medicine treatment. Methods : Five patients were hospitalized and treated with herbal medicine, acupuncture, pharmacopuncture, cupping, and Chuna manual therapy. Patients were assessed for Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), EuroQol-FiveDimensions (EQ-5D), and Cobb's angle. Results : In all patients, NRS, ODI, and Cobb's angle decreased, while the EQ-5D score increased. Conclusions : As seen in these five cases, complex Korean medicine treatment with Chuna manual therapy has effects on the management of nonstructural scoliosis.

화담청화탕이 acetic acid로 유발된 흰쥐 위궤양 점막의 내분비세포와 점액의 조직화학적 변화 (The Changes of Mucin and Endocrine cells of Mucosa of Acetic Acid-Induced Gastric Ulcer after Administration of Whadamcheongwha-tang Extract in Rat)

  • 강경래;육상원;고형근;이광규;이창현
    • 동의생리병리학회지
    • /
    • 제16권6호
    • /
    • pp.1170-1176
    • /
    • 2002
  • We examined the effects of Whadamcheongwha-tang(WDCWT) extract on the acetic-acid induced antigastric ulcer in rats. These experiments investigated the numerical changes of gastrin and histamine secreting cells of the gastric mucosa by immunohistochemical method, and the changes of mucin of gastric mucosa by PAS-AB stain methods after the oral administration of WDCWT extract(1.0ml/day) and omeprazole(0.2mg/day) for 1, 3 and 6 weeks. The result are as follows; 1. When WDCWT extract was administrated for 1, 3, 6 weeks, in result, gastrin secreting cells in gastric mucosa were increased compared to the control group. 2. When WDCWT extract was administrated for 1, 3, 6 weeks, in result, the density of immunoreactive gastrin cells was increased compare to the control group. 3. When WDCWT extract was administrated for 1, 3, 6 weeks, in results, the changs of mucosal thickness stained by PAS/PAS-AB was increased compared to the control group. 4. When WDCWT extract was administrated for 1, 3, 6 weeks, in results, the density of PAS stain was decreased compare to control group, but density of AB stain was increased compare to control group. The results suggest that WDCWT extract inhibits a gastric acid secretion in rat gastric mucosa, and is useful in the treatment of the hyperacidity and gastric ulcer.

항(抗)Stress 실험에 관한 비교 연구 (The study of comparison about the stress's control experiments)

  • 김근우;구병수
    • 동의신경정신과학회지
    • /
    • 제8권1호
    • /
    • pp.111-125
    • /
    • 1997
  • This study was done in order to investigate Oriental Medicine's meaning on stress, the stress is due to animal experiments.Methods:This research was done by animal experiments's results based on 41 animal experiment treatises carried out by 24 prescriptions about stress control. Each experiments were compared with same conditions, minimizing the experiments differences. The results were analyzed by p-value and Increas e·Decrease percentage of experiments result's numerical value. Results:1. Inquire into frequency in use of each stress stimulus and measuring items, the restriction stimulus stress and measuring the content of catecholamines are numerous.2. Significance of stress stimuluses based on experments's results is good by restriction stimulus.3. Oriental Medicine's meaning for stress is pathological phenomenon of Seven Emotion(七情). Stagnant the Energy(氣鬱), the Fire(火), Dam(痰), Lack of the general Blood thing(血虛), and reaction of an individual body.4. Inguire into the effects of frequency in use of experiments's Herb drugs, Herb Drugs of Tonifing the general Blood thing depend on stabilized Mind(補血安神), Circulated the Energy and Digest(理氣消導), Tonifing the general Blood thing(補血), Clearing the Mind(淸心), Removing the Dam(祛痰) are numerous.5. From a Sasang Medical point of view, experimental use of Herb Drugs are Soeum-in(少陰人) Herb Drugs are numerous.According to above results, it is considered that Herb Drugs of Tonifing the general Blood thing depend on stabilized Mind(補血安神), Circulated the Energy and Digest(理氣消導), Tonifing the general Blood thing(補血), Clearing the Mind(淸心), Removing the Dam(祛淡), and Soeum-in(少陰人) Herb Drugs are used to prevent stress and related diseases.

  • PDF

광섬유 냉각장치의 헬륨 주입기 설계를 위한 전산열유동해석 (Computational Thermo-Fluid Analysis for the Effects of Helium Injection Methods on Glass Fiber Cooling Process in an Optical Fiber Manufacturing System)

  • 박신;김경진;김동주;박준영;곽호상
    • 한국기계가공학회지
    • /
    • 제13권2호
    • /
    • pp.124-130
    • /
    • 2014
  • In a mass manufacturing system of optical fibers, the sufficient cooling of glass fibers freshly drawn from a draw furnace is essential, asinadequately cooled glass fibers can lead to poor resin coating on the fiber surface and possibly fiber breakage during the process. In order to improve fiber cooling at a high drawing speed, it is common to use a helium injection into a glass fiber cooling unit in spite of the high cost of the helium supply. The present numerical analysis carried out three-dimensional thermo-fluid computations of the cooling gas flow and heat transfer on moving glass fiber to determine the cooling performance of glass fiber cooling depending on the method of helium injection. The results showed that afront injection of helium is most effective compared to a uniform or rear injection for reducing air entrainment into the unit and thus cooling the glass fibers at a high fiber drawing speed. However, above a certain amount of injected helium, there was no more increase of the cooling effect regardless of the helium injection method.

엑셀 프로그램을 활용한 정역학 교육 사례 (Application of MS Excel in Teaching Statics)

  • 김영흡
    • 대한기계학회논문집 C: 기술과 교육
    • /
    • 제2권1호
    • /
    • pp.21-28
    • /
    • 2014
  • MS 엑셀 프로그램은 사업 영역의 다양한 분야에서 활용되고 있는 스프레드시트 프로그램이다. MS 엑셀 프로그램은 대부분의 PC 에서 이용 가능하기 때문에 학생들을 위한 교육적인 목적으로 도 널리 이용되는데, 과학과 공학 분야에서는 주로 수치해석과 공식의 응용 등에 주로 사용된다. 본 논문에서는 기계공학의 필수 과목인 정역학을 교육함에 있어 필수 공식을 활용하기 위한 MS 엑셀 프로그램의 교육사례를 소개한다. 또한, 엑셀 응용 프로그램에 대한 깊은 이해를 위하여 매크로와 비주얼 베이직을 이용하여 응용 프로그램을 개발하는 과정에 대해서도 기술한다. 학생들은 MS 엑셀 프로그램의 기본 함수를 이용하여 정역학 문제를 해결할 수 있었을 뿐만 아니라 매크로와 비주얼 베이직을 이용하여 복잡한 문제를 체계적으로 푸는 방법을 습득하고, 응용프로그램을 작성할 수 있었다.

Fuzzy reliability analysis of laminated composites

  • Chen, Jianqiao;Wei, Junhong;Xu, Yurong
    • Structural Engineering and Mechanics
    • /
    • 제22권6호
    • /
    • pp.665-683
    • /
    • 2006
  • The strength behaviors of Fiber Reinforced Plastics (FRP) Composites can be greatly influenced by the properties of constitutive materials, the laminate structures, and load conditions etc, accompanied by many uncertainty factors. So the reliability study on FRP is an important subject of research. Many achievements have been made in reliability studies based on the probability theory, but little has been done on the roles played by fuzzy variables. In this paper, a fuzzy reliability model for FRP laminates is established first, in which the loads are considered as random variables and the strengths as fuzzy variables. Then a numerical model is developed to assess the fuzzy reliability. The Monte Carlo simulation method is utilized to compute the reliability of laminas under the maximum stress criterion. In the second part of this paper, a generalized fuzzy reliability model (GFRM) is proposed. By virtue of the fact that there may exist a series of states between the failure state and the function state, a fuzzy assumption for the structure state together with the probabilistic assumption for strength parameters is adopted to construct the GFRM of composite materials. By defining a generalized limit state function, the problem is converted to the conventional reliability formula that enables the first-order reliability method (FORM) applicable in calculating the reliability index. Several examples are worked out to show the validity of the models and the efficiency of the methods proposed in this paper. The parameter sensitivity analysis shows that some of the mean values of the strength parameters have great influence on the laminated composites' reliability. The differences resulting from the application of different failure criteria and different fuzzy assumptions are also discussed. It is concluded that the GFRM is feasible to use, and can provide an effective and synthetic method to evaluate the reliability of a system with different types of uncertainty factors.

Damage assessment of shear connectors with vibration measurements and power spectral density transmissibility

  • Li, Jun;Hao, Hong;Xia, Yong;Zhu, Hong-Ping
    • Structural Engineering and Mechanics
    • /
    • 제54권2호
    • /
    • pp.257-289
    • /
    • 2015
  • Shear connectors are generally used to link the slab and girders together in slab-on-girder bridge structures. Damage of shear connectors in such structures will result in shear slippage between the slab and girders, which significantly reduces the load-carrying capacity of the bridge. Because shear connectors are buried inside the structure, routine visual inspection is not able to detect conditions of shear connectors. A few methods have been proposed in the literature to detect the condition of shear connectors based on vibration measurements. This paper proposes a different dynamic condition assessment approach to identify the damage of shear connectors in slab-on-girder bridge structures based on power spectral density transmissibility (PSDT). PSDT formulates the relationship between the auto-spectral densities of two responses in the frequency domain. It can be used to identify shear connector conditions with or without reference data of the undamaged structure (or the baseline). Measured impact force and acceleration responses from hammer tests are analyzed to obtain the frequency response functions at sensor locations by experimental modal analysis. PSDT from the slab response to the girder response is derived with the obtained frequency response functions. PSDT vectors in the undamaged and damaged states can be compared to identify the damage of shear connectors. When the baseline is not available, as in most practical cases, PSDT vectors from the measured response at a reference sensor to those of the slab and girder in the damaged state can be used to detect the damage of shear connectors. Numerical and experimental studies on a concrete slab supported by two steel girders are conducted to investigate the accuracy and efficiency of the proposed approach. Identification results demonstrate that damages of shear connectors are identified accurately and efficiently with and without the baseline. The proposed method is also used to evaluate the conditions of shear connectors in a real composite bridge with in-field testing data.

A new high-order response surface method for structural reliability analysis

  • Li, Hong-Shuang;Lu, Zhen-Zhou;Qiao, Hong-Wei
    • Structural Engineering and Mechanics
    • /
    • 제34권6호
    • /
    • pp.779-799
    • /
    • 2010
  • In order to consider high-order effects on the actual limit state function, a new response surface method is proposed for structural reliability analysis by the use of high-order approximation concept in this study. Hermite polynomials are used to determine the highest orders of input random variables, and the sampling points for the determination of highest orders are located on Gaussian points of Gauss-Hermite integration. The cross terms between two random variables, only in case that their corresponding percent contributions to the total variation of limit state function are significant, will be added to the response surface function to improve the approximation accuracy. As a result, significant reduction in computational cost is achieved with this strategy. Due to the addition of cross terms, the additional sampling points, laid on two-dimensional Gaussian points off axis on the plane of two significant variables, are required to determine the coefficients of the approximated limit state function. All available sampling points are employed to construct the final response surface function. Then, Monte Carlo Simulation is carried out on the final approximation response surface function to estimate the failure probability. Due to the use of high order polynomial, the proposed method is more accurate than the traditional second-order or linear response surface method. It also provides much more efficient solutions than the available high-order response surface method with less loss in accuracy. The efficiency and the accuracy of the proposed method compared with those of various response surface methods available are illustrated by five numerical examples.

대단면 터널 라이닝 콘크리트 타설 기법 개선에 관한 연구 (Improvement of Concrete Lining Construction Method in Large Section Tunnel)

  • 김상환;나경웅;고성일
    • 한국터널지하공간학회 논문집
    • /
    • 제8권1호
    • /
    • pp.77-86
    • /
    • 2006
  • 터널라이닝에 대한 필요성 여부에 대한 논란은 지속적으로 되고 있으나, 대부분의 터널기술자들은 라이닝의 필요성에 대하여 동의하고 있다. 따라서 설계 및 시공상의 라이닝 특성을 고려한 콘크리트 라이닝 품질향상방안 수립을 위하여 근본적인 문제점을 파악하고 해결하는데 도움이 되고자한다. 본 논문에서는 균열발생량이 상대적으로 많은 대단면 4차로 터널을 대상으로 하여 콘크리트라이닝 시공에서부터 터널운용전 발생되는 초기균열에 대한 발생원인 분석을 실시하고, 국내 콘크리트 라이닝 시공특성을 파악하기 위한 사례조사를 실시하였다. 이를 바탕으로 하여 균열발생 최소화를 위한 시공개선방안을 제안하고, 개선방안에 대한 라이닝 콘크리트 타설모형실험 및 강재거푸집내 콘크리트의 유동분석을 수행하여 고품질 콘크리트 라이닝시공을 위한 제안방안의 효율성을 검증하였다.

  • PDF

횡류식 선택대배기환기에서의 배연특성에 관한 연구 (A study on the effective fire and smoke control in transverse oversized exhaust ventilation)

  • 한상필;전용한
    • 한국터널지하공간학회 논문집
    • /
    • 제13권6호
    • /
    • pp.451-462
    • /
    • 2011
  • 도로터널의 환기 시스템은 차량 화재시 안전한 대피환경을 조성하는데 중요한 역할을 하며 종류환기방식과 횡류환기방식으로 대별된다. 본 연구에서는 횡류환기방식에서 대배기구방식에 대한 터널내 풍속, 배연풍량, 개방되는 배기구의 위치에 따른 유동가시화에 대하여 선행 연구와 FDS 시뮬레이션에 의한 결과를 비교하여 연기의 이동특성을 고찰하였다. 그 결과, 연기발생량(Vc=0)에 따른 배연풍량을 제어하여 연기를 피난허용범위 250 m 이내로 제한할 수 있었으며, 터널풍속이 1.75 m/s 와 2.5 m/s일 때 배연풍량은 각각 $173m^3/s$, $236m^3/s$ 을 초과하여야만 연기이동 거리를 250 m로 제한할 수 있었으며 화재지점 가까이에 있는 2개의 배기구를 동시에 개방하는 경우가 배연의 효과가 현저하게 높게 나타났다.