• 제목/요약/키워드: Continuous field

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장애물 환경에서 경로 생성을 위한 알고리즘 연구 (The Study of Algorithm for the Path generation in the Obstacles Environment)

  • 황하성;양승윤;이만형
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.430-433
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    • 1996
  • In This paper, we design the developed path generation method which is named that CBPM(Continuous path generation method Based artificial Potential field) that is able to be used in the obstacles environment. This CBPM is designed so that it puts together two obstacle avoidance algorithm-the continuous path generation method and the artificial potential field method. Here, the continuous path generation method generate the safety path using continuous path curvature. But, this method has demerits when used in obstacles environment in which are closely located. Another method which is named the artificial potential field method generates the path with the artificial potential field in the obstacles environment. But, APFM has local minima in certain places and unnecessarily calculates the path in which obstacles are not located. So, the developed path generation method, CBPM, is suggested and performances in many different obstacles environments are shown by using computer simulation.

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A Study on the Improvement of Stress Field Analysis in a Domain Composed of Dissimilar Materials

  • Song, Kee-Nam;Lee, Jin-Seok
    • Nuclear Engineering and Technology
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    • 제30권3호
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    • pp.202-211
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    • 1998
  • Interfacial stresses at two-material interfaces and initial displacement field over the entire domain are obtained by modifying the potential energy functional with a penalty function, which enforces continuity of the stresses at the interface of two materials. Based on the initial displacement field and interfacial stresses, a new methodology to generate a continuous stress field over the entire domain has been proposed by combining the modified projection method of stress-smoothing and Loubignac's iterative method of improving the displacement field. Stress analysis is carried out on two examples made of dissimilar materials : one is a two-material cantilever composed of highly dissimilar materials and the other is a zirconium-lined cladding tube made of slightly dissimilar materials. Results of the analysis show that the proposed method provides an improved continuous stress field over the entire domain, and accurately predicts the nodal stresses at the interface, while the conventional displacement-based finite element method produces significant stress discontinuities at the interface. In addition, the total strain energy evaluated from the improved continuous stress field converges to the exact value in a few iterations.

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Continuous Variable을 갖는 Mean Field Annealing과 그 응용

  • 이경희;조광수;이원돈
    • ETRI Journal
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    • 제14권3호
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    • pp.67-74
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    • 1992
  • Discrete variable을 갖는 Mean Field Theory(MFT) neural network은 이미 많은 combinatorial optimization 문제에 적용되어져 왔다. 본 논문에서는 이를 확장하여 continuous variable을 갖는 mean field annealing을 제안하고, 이러한 network에서 integral로 표현되는 spin average를 mean field에 기초하여 어렵지 않게 구할 수 있는 one-variable stochastic simulated annealing을 제안하였다. 이런 방법으로 multi-body problem을 single-body problem으로 바꿀 수 있었다. 또한 이 방법을 이용한 응용으로서 통계학에서 잘 알려진 문제중의 하나인 quantification analysis 문제에 적용하여 타당성을 보였다.

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소음환경에 대한 근속년수별 작업자의 주관적 반응분석 (An Analysis of Subjective Responses on Noise Environment According to Operators' Continuous Service)

  • 이동춘;황규성;이임순
    • 산업경영시스템학회지
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    • 제12권20호
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    • pp.63-69
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    • 1989
  • This paper tries to define and analyse the subjective responses on noise environment according to operators continuous service in the field. The hypothesis of this paper is that the longer they serve in the same field, the more they feel seriously on noise effects. A predesigned enquete was handed out to 500 operators, and performed Friedman Test in order to check the hypothesis Concludingly, this paper accepts the hypothesis by year of continuous service-questionaire number analysis.

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CONTINUOUS DATA ASSIMILATION FOR THE THREE-DIMENSIONAL SIMPLIFIED BARDINA MODEL UTILIZING MEASUREMENTS OF ONLY TWO COMPONENTS OF THE VELOCITY FIELD

  • Anh, Cung The;Bach, Bui Huy
    • 대한수학회지
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    • 제58권1호
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    • pp.1-28
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    • 2021
  • We study a continuous data assimilation algorithm for the three-dimensional simplified Bardina model utilizing measurements of only two components of the velocity field. Under suitable conditions on the relaxation (nudging) parameter and the spatial mesh resolution, we obtain an asymptotic in time estimate of the difference between the approximating solution and the unknown reference solution corresponding to the measurements, in an appropriate norm, which shows exponential convergence up to zero.

작약 검은뿌리썩음병 발생실태와 방제 (Occurrence and Control of Black Root Rot of Peony (Paeonia lactiflora) on Continuous Cropping)

  • 최성용;박경석;김기재;김재철
    • 식물병연구
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    • 제10권4호
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    • pp.268-271
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    • 2004
  • 작약검은뿌리썩음병은 연작을 할 경우 현저히 발생이 증가하였으며, 태백작약 품종에 비해 의성작약 품종에서 좀 더 심한 발병을 보였다. 종구로 사용하는 뇌두를 약제에 침지시 병원균은 검출되지 않았으나 물에만 침지한 경우 병원균이 검출되었다. 연작지의 토양개량시 검은뿌리썩음병의 방제는 효과가 없었으나 다조메입제로 토양을 훈증소독할 경우 토양훈증처리구에서 주근중과 근장이 단순연작구와 비교하여 50% 정도 증가하였으며 검은뿌리썩음병의 발병율은 무처리구의 경우 40.6% 정도 발병되었으나 토양훈증처리구는 4.7% 정도로 발병되어 아주 높은 방제효과를 보였으며 종구소독과 훈증처리를 병행시 발병율은 더욱 낮아졌다.

평균장 이론을 이용한 전량화분석 문제의 최적화 (Quantification Analysis Problem using Mean Field Theory in Neural Network)

  • 조광수
    • 한국정보처리학회논문지
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    • 제2권3호
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    • pp.417-424
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    • 1995
  • 본 논문에서는 정량화(Quantification) 문제를 MFT(Mean Field Theroy)를 통해서 해결하는 기법을 제안한다. 통계학에서 중요한 문제의 하나인 정량화 문제는 주어진 공간에서 대상들간의 유사성에 따라서 최적의 상태를 갖도록 하는 문제이다. 평균장 접근 방법에 기초한 한개의 변수로 표현되는 확률적 시뮬레이티드 아닐링을 제안하고 정량화 문제를 패널티(penalty) 파라메타 항을 첨가한 비한정된 최적화 문제로 변형하 여 MFT를 적용하였다. 또한 연속변수를 갖는 신경회로망에서 실제 값을 계산하는 것 보다 평균장 접근방법으로 계산하는것이 더 빠르게 계산될 수 있음을 확인하였다. 본 논문에서 제안한 방법이 실험결과 해석적인 방법보다 좋은 정량적 결과를 보였다.

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자성유체를 이용한 다이나믹형 빙축열 시스템에 관한 실험적 연구 (An Experimental Study of Dynamic Type Ice Storage System Using Magneticfluid)

  • 황승식
    • 대한기계학회논문집B
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    • 제28권12호
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    • pp.1484-1493
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    • 2004
  • In this study, it induced to a conclusion below by experiment consideration to regarding an effective supercooling ends method of the flow cooling water in a tube of continuous ice making method and the static cooling water in a tube of continuous ice making method which used magneticfluid in a dynamic type ice storage system. Continuous ice making in a tube of the flow cooling water was shortened about 12 minutes until supercooling ends that case which gave vertical eccentricity rotation magnetic field 120rpm than did not provide magnetic field by experimental result that was tested to supercooling ends effect from shape control of magneticfluid. Continuous ice making method in a tube of the static cooling water compared with and reviewed the case that was not provided with the magnetic field and exposed cooling surface instantaneously by magnetic field. It confirmed that supercooling degree $\Delta$ $T_{c}$, $\Delta$ $T_{s}$, and $\Delta$ $T_{w}$ became lower because of heat transfering increasing by the occurrence of natural convection between after cooling starting progress time 1∼3 minutes if it did not give a magnetic field, and peformed the supercooling ends when natural convection occurred confirmed that refrigerating capacity was better. That relation $\Delta$ $T_{c}$, and $t_{e}$/($\Delta$ $T_{c}$-$\Delta$ $T_{s}$) after convection occurred, was not depended on $T_{b}$ and initial temperature if the depth of water and thickness of magneticfluid were regular and it was possible to verify conjecture of tp from $\Delta$ $T_{s}$ and $\Delta$ $T_{c}$.lar and it was possible to verify conjecture of tp from $\Delta$ $T_{s}$ and $\Delta$ $T_{c}$.c}$.>.

하중 제어법을 이용한 파이프 줄기초의 현장 인발저항 특성 (Characteristics of Field Uplift Tests of Continuous Greenhouse using the Load Control Method)

  • 임성윤;김명환;김유용;유석철;김석진;임재삼
    • 한국농공학회논문집
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    • 제60권4호
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    • pp.105-111
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    • 2018
  • Institutional inertia anti-disaster standard was presented mainly on the upper surface, it is necessary to improve to the soil type standard and uplift the resistance standard greenhouse that are vulnerable to strong winds. In this study, we carried out a field test using the load control method in order to evaluate the uplift resistance of continuous foundation of greenhouse with different depths of the rafters. Institutional inertia anti-disaster standard of greenhouse foundation did not protect the greenhouse structure from the damages caused by strong winds and heavy snow. Therefore, field tests for behavior characteristics of continuous greenhouse foundation were carried out to ensure stable facility cultivation. The field test condition was evaluated using different embedded depth as follows: 30cm, 40cm, 50cm and spacing 50cm, 60cm, 70 cm. As a result of the uplift resistance field tests using the load control method, the minimum uplift resistance was found to be over 90kg and uplift resistance displacement was 9.4mm. Uplift resistance of the continuous greenhouse foundation was in the range of 90-180 kg according to embedded depth and spacing. Using the test condition, there was no constant trend in the uplift resistance.

A Numerical Analysis of Molten Steel Flow Under Applied Magnetic Fields in Continuous Casting

  • Yoon, Teuk-Myo;Kim, Chang-Nyung
    • Journal of Mechanical Science and Technology
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    • 제17권12호
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    • pp.2010-2018
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    • 2003
  • Although continuous casting process has highly developed, there still remain many problems to be considered. Specifically, two vortex flows resulting from impingement against narrow walls make a flow field unstable in a mold, and it is directly related to internal and external defects of steel products. To cope with this instability, EMBR (Electromagnetic Brake Ruler) technique has been lately studied for the stability of molten steel flow, and it is revealed that molten steel flow in a mold can be controlled with applied magnetic field. However, it is still difficult to clarify flow pattern in an EMBR caster due to complex correlations among variables such as geometric factors, casting conditions, and the place and the intensity of charged magnetic field. In the present study, flow field in a mold is focused with different conditions of electromagnetic effect. To accurately analyze the case, three dimensional low Reynolds turbulent model and appropriate boundary conditions are chosen. To evaluate the electromagnetic effect in molten steel flow, dimensionless numbers are employed. The results show that the location and the intensity of the applied magnetic field significantly influence the flow pattern. Both impingement and internal flow pattern are changed remarkably with the change of the location of applied magnetic field. It turns out that an insufficient magnetic force yields adverse effect like channeling, and rather lowers the quality of steel product.