• 제목/요약/키워드: mean field theory

검색결과 117건 처리시간 0.025초

점증 선행 하중으로 개량하는 연약지반의 계측기반 침하량 예측방법 개발 (Prediction Method of Settlement Based on Field Monitoring Data for Soft Ground Under Preloading Improvement with Ramp Loading)

  • 우상인;윤찬영;백승경;정충기
    • 한국지반공학회논문집
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    • 제24권10호
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    • pp.83-91
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    • 2008
  • 현장계측 자료를 이용하여 연약지반의 향후 침하거동을 예측하는 기존의 방법들은 모두 즉시재하 조건을 가정하고 개발된 방법으로써 실제로는 연약지반의 안정성 등을 고려하여 점증재하가 이루어지는 현장에 적용하기에는 많은 제약이 있다. 본 연구에서는 연약층의 두께, 성토하중 크기, 선행압밀하중, 배수거리, 성토속도 등의 다양한 영향인자를 고려하였으며 점증재하가 완료된 이후의 지반개량 기간에도 지속적으로 예측 정확도를 높일 수 있는 계측기반 침하거동 예측기법을 개발하였다. 점증재하 과정에서의 예측방법과 성토완료 이후의 예측방법이 개발되었으며, 성토 완료 이후의 예측방법은 기하학적 보정을 이용한 정확도 향상기법과 확률론적 보정을 이용한 정확도 향상기법 두 가지를 제안하였다. 대형압밀시험 결과를 이용한 예측기법의 적용성 검증 결과, 기존의 예측기법을 적용할 수 없는 점증재하 초기에도 비교적 적은 데이터를 이용하여 상당히 높은 정확도를 가지고 침하거동을 예측할 수 있었다. 또한, 성토완료이후에도 기존 예측기법과 제안된 방법의 비교, 분석 결과 최종침하량과 RMSE에서 모두 제안된 방법이 기존의 예측기법에 비하여 우수한 예측결과를 보였다.

기계 산업 분야의 통합 환경 조화와 안전을 위한 작업복 색채 배색 평가 (Color Arrangement Evaluation on Working Clothes for Safety and Integrated Environment Harmony in Machinery Industry Fields)

  • 박혜원;양정희
    • 패션비즈니스
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    • 제16권5호
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    • pp.207-219
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    • 2012
  • It is intended to study the colors of work environment and the working clothes colors between humans and environment with application of the arrangement of working clothes colors to domestic machinery companies that play pivotal roles in the industry of Korea. The purpose of this study is to provide the foundation of color plan for the integrated environmental harmonization and the safety of industrial sites by analyzing the photographs of working clothes in the sires in consideration of the functions of colors (clearness, attention-getting, and safety) using the Faber Birren's Color Harmony and by analyzing the result of a questionnaire survey. The study was conducted by the method to shoot a worksite using a digital camera after wearing 24 sets of uniforms, which were developed by the color plan established in a previous study, in the same worksite. The shooting place was an outdoor steel sheet inspection site of D company, a machinery company in Changwon-si, Gyeongnam, and the intensity of illumination was 2400lux. 24 pieces of images were printed in 5x7 inch size and a questionnaire survey was performed at 5-point scale. The questionnaire survey was performed for 13 subjects consisting of 6 field professionals having more than 30 years of experiences, 4 clothes color professionals, and 3 industrial engineering professionals. The result of the survey was statistically analyzed by the method of frequency analysis using IBM SPSS Statistics 20 Program. As the result of assessment of basic four colors (yellow green, sky blue, blue, and violet) of working clothes, yellow green, sky blue, and blue showed high mean values in (Tint)+(Shade)+(Tone)+(Gray) equation indicating that its is a harmonized equation.

압밀응력비에 따른 낙동강모래의 비배수전단거통 특성 (Variation of Undrained Shear Behavior with Consolidation Stress Ratio of Nakdong River Sand)

  • 김영수;정성관;송준혁;정동길
    • 한국지반공학회논문집
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    • 제19권4호
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    • pp.83-93
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    • 2003
  • 본 연구에서는 낙동강 하류 을숙도에 분포하는 0.558%의 세립분을 함유한 자연 사질토 지반에 대하여 느슨, 중간, 그리고 조밀한 지반 상태를 재현하여 초기정적전단응력의 영향을 정적 및 동적 시험을 통해 응력경로와 과잉간극수압 소산 및 잔류변형 거동을 규명하고, Bolton 이론에 의거한 파괴시 최대 유효마찰각을 상대밀도에 의한 영향과 구속압의 영향을 고려하여 제시하였다. 파괴선과 상전이점의 거리는 초기전단응력이 증가할수록 가까워지고, 느슨한 모래의 경우 그 영향이 커서 조밀한 모래의 응력경로로 접근하는 경향을 보인다. 압밀응력비 조건이 1.4에서 1.8로 변함에 따라, 상대밀도의 증가와 함께 보다 큰 액상화 저항강도를 보이고 조밀한 상대밀도 조건에서는 유사한 CSR값을 보였다.

굴삭기 엔진용 저압연료펌프 유체의 유동변화에 대한 수치해석적 연구 (A Study for Numerical Analysis of Flow Variation on Low Pressure Fuel Pump Fluid using Excavator Engine)

  • 이일권;김승철
    • 한국가스학회지
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    • 제19권6호
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    • pp.47-53
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    • 2015
  • 이 논문은 굴삭기 엔진용 저압연료 펌프의 연료 유동에 대한 유동장 및 속도, 압력에 관하여 수치해석 방법을 적용하여 연구한 것이다. 연료 펌프의 압력 분포는 로터의 회전각도에 따라 연속적으로 변하며, 특히 회전각도 $40^{\circ}$에서 상대적으로 매우 높은 토출부 압력과 낮은 흡입부 압력이 동시에 발생함을 확인하였다. 또한, 이 각도에서 누설유동 유속이 가장 증가함을 알 수 있었다. 그리고 연료 펌프의 로터 회전수의 증가에 따라 평균토출유량이 선형적으로 증가하였고, 간극크기가 감소함에 따라 토출유량이 로터 기어 사이의 배제용적으로부터 계산된 이론적 토출유량 0.0712kg/s 으로 접근하는 것을 확인할 수 있었다.

Stochastic hygrothermoelectromechanical loaded post buckling analysis of piezoelectric laminated cylindrical shell panel

  • Lal, Achchhe;Saidane, Nitesh;Singh, B.N.
    • Smart Structures and Systems
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    • 제9권6호
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    • pp.505-534
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    • 2012
  • The present work deals with second order statistics of post buckling response of piezoelectric laminated composite cylindrical shell panel subjected to hygro-thermo-electro-mechanical loading with random system properties. System parameters such as the material properties, thermal expansion coefficients and lamina plate thickness are assumed to be independent of the temperature and electric field and modeled as random variables. The piezoelectric material is used in the forms of layers surface bonded on the layers of laminated composite shell panel. The mathematical formulation is based on higher order shear deformation shell theory (HSDT) with von-Karman nonlinear kinematics. A efficient $C^0$ nonlinear finite element method based on direct iterative procedure in conjunction with a first order perturbation approach (FOPT) is developed for the implementation of the proposed problems in random environment and is employed to evaluate the second order statistics (mean and variance) of the post buckling load of piezoelectric laminated cylindrical shell panel. Typical numerical results are presented to examine the effect of various environmental conditions, amplitude ratios, electrical voltages, panel side to thickness ratios, aspect ratios, boundary conditions, curvature to side ratios, lamination schemes and types of loadings with random system properties. It is observed that the piezoelectric effect has a significant influence on the stochastic post buckling response of composite shell panel under various loading conditions and some new results are presented to demonstrate the applications of present work. The results obtained using the present solution approach is validated with those results available in the literature and also with independent Monte Carlo Simulation (MCS).

Influence of micromechanical models on the bending response of bidirectional FG beams under linear, uniform, exponential and sinusoidal distributed loading

  • Meksi, Abdeljalil;Benyoucef, Samir;Sekkal, Mohamed;Bouiadjra, Rabbab Bachir;Selim, Mahmoud M.;Tounsi, Abdelouahed;Hussain, Muzamal
    • Steel and Composite Structures
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    • 제39권2호
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    • pp.215-228
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    • 2021
  • This paper investigates the effect of micromechanical models on the bending behavior of bidirectional functionally graded (BDFG) beams subjected to different mechanical loading. The material properties of the beam are considered to be graded in both axial and thickness directions according to a power law. The beam's behavior is modeled by the mean of quasi 3D displacement field that contain undetermined integral terms and involves a reduced unknown functions. Navier's method is employed to determine and compute the displacements and stress for a simply supported beam. Different homogenization schemes such as Voigt, Reus, and Mori-Tanaka are employed to analyze the response of the BDFG beam subjected to linear, uniform, exponential and sinusoidal distributed loading. The results obtained by the present method are compared with available results in the literature and a good agreement was found. Several numerical results are presented in tabular form and in figures to examine the effects of the material gradation, micromechanical models and types of loading on the bending response of BDFG beams. It can be concluded that the present theory is not only accurate but also simple in predicting the bending response of BDFG beam subjected to different static loads.

비판적 수학교육 관점에 따른 수학교과서 분석준거 개발: 전문가 델파이 조사를 중심으로 (Delphi Survey to Develop an Analysis Framework for Mathematics Textbooks from a Critical Mathematics Education Perspective)

  • 송륜진;주미경
    • 대한수학교육학회지:수학교육학연구
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    • 제27권1호
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    • pp.113-135
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    • 2017
  • 본 연구는 비판적 수학교육의 관점에서 수학교과서를 분석하기 위한 분석준거 개발을 목표로 하여 이루어졌다. 이를 위한 첫 단계로서 비판적 수학교육의 이론적 근간이 되는 비판 이론과 비판적 교육이론에 대한 문헌분석을 통해 비판적 수학교육의 철학적, 인식론적 기저를 고찰하였다. 또한 비판적 수학교육에 대한 국내외 문헌을 분석하여 비판적 수학교육의 개념화 논의, 실제 수업사례 등을 종합하여 '비판적 수학교육 관점에 따른 수학교과서 분석준거 안'을 구성하였다. 이후 제시한 준거 안에 대한 타당도를 검증하기 위해 전문가 델파이 조사를 실시하였다. 델파이 조사 분석 결과에 따라 제시한 준거 안을 수정, 보완하여 '고전적 지식', '공동체적 지식', '대화적 지식', '정치적 지식' 네 범주로 이루어진 '비판적 수학교육의 관점에 따른 수학교과서 분석준거'를 최종적으로 개발하였다.

족부와 족관절에서의 신경내 결절종 (Intraneural Ganglion Cyst in Foot and Ankle)

  • 최장석;김광희;곽지훈;박홍기;이신우
    • 대한족부족관절학회지
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    • 제15권4호
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    • pp.223-231
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    • 2011
  • Purpose: Pathogenesis of intraneural ganglion is controversial, however, the synovial theory that the intraarticular region is the origination of disease has come into the spotlight nowadays. But there are a few researches about intraneural ganglion in foot and ankle. We studied 7cases of intraneural ganglion. We are going to prove the synovial theory by indentifying articular branch of intraneural ganglion. Materials and Methods: From August 2003 to May 2011, we evaluated 7 ouf of 8 patients diagnosed as a intraneural ganglion in foot and ankle. The gender ratio were 4 male and 3 female, and the mean age at the time of surgery was 52.9 years. Clinically, we checked pre and post operative symptom, muscle tone and whether loss of muscle tone and sensation exists. We analyzed surgical records and preoperative MRI and compared those with intra-operative finding. Results: In MRI analysis of 7cases, the connection around the joints were confirmed, and 1 case was confirmed in the retrospective analysis of MRI. Intraneural ganglions occurred in medial plantar nerve 3 cases, lateral plantar nerve 1 case, superficial peroneal nerve 1 case and sural nerve 1 case. We could not found recurrence during the follow up periods. Most patients relieved pain after operation, but recovery of sensation was unsatisfactory. We could find some cases pathological finding of the nerve intraoperatively, and clinical result of that cases was poor. Conclusion: Intraneural ganglion can occur in various parts in foot and ankle. We concluded that the intranneural ganglion originated from joint by identifying the artichlar branch of ganglion. Due to its small size, it is difficult to find articular branch in operation field. But we do our best to find and remove articular branch. Currently, considering the small amount of research in foot and ankle, more research about articular brach is needed.

호모 테아트룸: '사이'의 연극으로서의 보알(Augusto Boal) 연극 고찰 (Homo Theatrum: A Study of Boal's Theatre as 'Saiee' Theatre)

  • 김현정
    • 한국연극학
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    • 제40호
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    • pp.503-535
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    • 2010
  • 'Saiee', which could mean between, intra- and inter-, is a crucial topic in theatre as theatre has tension between actor and audience, reality and illusion, and everyday life and extraordinary life. Especially, it is interesting that the function of 'Saiee' is connected to extension and application of drama and theatre such as educational theatre, dramatherapy and applied drama/theatre. Such works are expected to educational or therapeutic effects, thus concern and support, demand and supply of these works is getting increased. However, it is true that researches on spirit, aesthetic and direction of these works are not sufficient, compared to quantitative increase and diversity. This study will explore Boal's Theatre of the Oppressed(TO from the below), which is key theory and technique of applied drama/theatre field with viewpoint of 'Saiee' theatre to look at spirit, aesthetic and direction of this field. Saiee's energy could observe the object with distance(distance), form the relationship with that object(inter) and create new circumstance through that relationship(intra). And Boal's TO tried to Saiee's theatre by using Saiee's dynamics variously. It bases on the phenomenon of metaxis. Boal's TO believes that drama/theatre is unique nature and ability of human being, that is to say, it is based on Homo Theatrum, human plays and does theatre. Therefore, the participant of Boal's TO is extended to everyone in everyday life. This activity is not only individual work to find his/her identity but also solidarity and possibility to change society which they belong to. It is the dynamics of 'Saiee' to make this possible. Boal's TO thinks that relationship and balance between individuality and sociality is important. The way of conversation in Boal's TO includes questioning, listening and communication. Unfamiliarity or distance of 'Saiee' makes interest in other people and question about them. Questioning through theatre and concern on other beings to search for the answer (this is listening), would be new relationship(and possibility) to extend him/herself. The communication and relationship leads to possibility and ability to create another world. This is the function of 'inter-' and 'intra-' in theatre of 'Saiee'. Lastly, it is various that Boal's TO as 'Saiee' theatre uses the dynamics of 'Saiee'. The diversity of technique comes from the application to humans in every moment and every time. To apply 'Saiee's aesthetic actively, concern and research on people 'now and here' should be proceed.

비정질 RE$Fe_2$-B (RE=Dy, Sm) 합금 리본에서 평균장 이론에 의한 교환상호작용 계산 (Mean Field Analysis of Exchange Coupling in Amorphous RE$Fe_2$-B (RE=Dy, Sm) Alloy Ribbons)

  • Lee, J. M.;J. K. Jung;S.H. Lim
    • 한국자기학회지
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    • 제11권3호
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    • pp.85-96
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    • 2001
  • 급속응고에 의해 제조된 비정질 (Dy$_{0.33}$Fe$_{0.67}$)$_{1-x}$ B$_{x}$(x=0 ,0.05, 0.1, and 0.15) 및 (Sm$_{0.33}$Fe$_{0.67}$)$_{1-x}$ B$_{x}$(x=0, 0.01, 0.02, and 0.03) (in atomic fraction) (원자 비) 합금 리본에 대하여 자화(온도 곡선을 구하였으며, 이를 평균장 이론에 근거한 이론적인 식을 사용하여 fitting함으로써 구성 원소들 사이의 교환상호작용의 크기를 계산하였다. DyFe$_2$-B계의 경우, Dy와 Fe 사이의 교환상호작용은 음의 부호를 가지는데, 이는 Dy와 Fe의 자화 방향이 반대임을 의미한다. Fe원소사이의 교환상호작용이 가장 크며, 반면에 Dy 원소들사이의 상호작용이 가장 작게 나타났다. SmFe$_2$-B계의 경우, 계산된 교환상호작용은 전부 양의 부호를 가지는데, 이는 스핀들 사이에 강자성 상호작용이 있음을 의미한다. Fe 원소들 사이의 상호작용과 Fe와 Sm사이의 상호작용은 매우 크며, 그 크기 또한 유사하다. Fe와 Sm 사이의 상호작용이 큰 것은, 이 원소들 사이의 상호작 용이 간접적임을 고려할 때 의외의 결과이며, 비정질 Sm-Fe합금의 고유 성질인 것으로 생각된다. 두 합금계 모두에서 Fe 원소들 사이의 교환상호작용은 B 함량이 증가함에 따라 증가하였는데, 이는 B 함량의 증가에 따라 Fe-Fe 간격이 증가하였기 때문으로 생각된다. 두 합금계 모두에서 자화와 큐리온도는 B의 함량이 증가함에 따라 감소하였다.감소하였다.다.

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