• 제목/요약/키워드: non-local parameters

검색결과 187건 처리시간 0.03초

Influence of exterior joint effect on the inter-story pounding interaction of structures

  • Favvata, Maria J.;Karayannis, Chris G.;Liolios, Asterios A.
    • Structural Engineering and Mechanics
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    • 제33권2호
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    • pp.113-136
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    • 2009
  • The seismic induced interaction between multistory structures with unequal story heights (inter-story pounding) is studied taking into account the local response of the exterior beam-column joints. Although several parameters that influence the structural pounding have been studied sofar, the role of the joints local inelastic behaviour has not been yet investigated in the literature as key parameter for the pounding problem. Moreover, the influence of the infill panels as an additional parameter for the local damage effect of the joints on the inter-story pounding phenomenon is examined. Thirty six interaction cases between a multistory frame structure and an adjacent shorter and stiffer structure are studied for two different seismic excitations. The results are focused: (a) on the local response of the critical external column of the multistory structure that suffers the hit from the slab of the adjacent shorter structure, and (b) on the local response of the exterior beam-column joints of the multistory structure. Results of this investigation demonstrate that the possible local inelastic response of the exterior joints may be in some cases beneficial for the seismic behaviour of the critical column that suffers the impact. However, in all the examined cases the developing demands for deformation of the exterior joints are substantially increased and severe damages can be observed due to the pounding effect. The presence of the masonry infill panels has also been proved as an important parameter for the response of the exterior beam-column joints and thus for the safety of the building. Nevertheless, in all the examined inter-story pounding cases the presence of the infills was not enough for the total amelioration of the excessive demands for shear and ductility of the column that suffers the impact.

Lack of Prognostic Value of Blood Parameters in Patients Receiving Adjuvant Radiotherapy for Breast Cancer

  • Cihan, Yasemin Benderli;Arslan, Alaettin;Cetindag, Mehmet Faik;Mutlu, Hasan
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권10호
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    • pp.4225-4231
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    • 2014
  • Aim: To determine prognostic value of blood parameters on overall and progression-free survival in cases received adjuvant radiotherapy and chemotherapy with diagnosis of stage I-III breast cancer. Materials and Methods: We retrospectively reviewed files of 350 patients with non-metastatic breast cancer who were treated in the Radiation Oncology Department of Kayseri Teaching Hospital between 2005 and 2010. Pretreatment white blood cell (WBC), neutrophil, monocyte, basophil and eosinophil counts, and the neutrophil/lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) were recorded. The relationship between clinicopathological findings and blood parameters was assessed. Results: Overall, 344 women and 6 men were recruited. Median age was $55.3{\pm}0.3$ years (range: 22-86). Of the cases, 243 (61.4%) received radiotherapy while 329 (94.3%), received chemotherapy and 215 (61.4%) received hormone therapy. Mean overall survival (OS) and progression-free survival (PFS) was 84.4 and 78.8 months, respectively. During follow-up, 48 patients died due to either disease-related or non-related causes. Local recurrence was detected in 14 cases, while distant metastasis was noted in 45 cases. In univariate analysis, age, pathology, perinodal invasion were significantly associated with overall survival, whereas gender, stage and hormone therapy were significantly associated with progression-free survival. In multivariate analysis, histopathological diagnosis (OR: 0.3; 95%: 0.1-0.7; p=0.006) and perinodal invasion (OR: 0.1; 95% CI: 0.1-1.3; p=0.026) were significantly associated with overall survival, whereas tumor stage (OR: 2.1; 95% CI: 0.0-0.7; p=0.014) and hormone therapy (OR: 2.1; 95%: 1.2-3.8; p=0.010) were significantly associated with progression-free survival. Conclusions: It was found that serum inflammatory markers including WBC, neutrophil, lymphocyte and monocyte counts, and NLR and PLR had no effect on prognosis in patients with breast cancer who underwent surgery and received adjuvant radiotherapy and chemotherapy.

Analysis of boundary conditions effects on vibration of nanobeam in a polymeric matrix

  • Belmahi, Samir;Zidour, Mohamed;Meradjah, Mustapha;Bensattalah, Tayeb;Dihaj, Ahmed
    • Structural Engineering and Mechanics
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    • 제67권5호
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    • pp.517-525
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    • 2018
  • In this study, we investigate the vibration of single-walled carbon nanotubes embedded in a polymeric matrix using nonlocal elasticity theories with account arbitrary boundary conditions effects. A Winkler type elastic foundation is employed to model the interaction of nanobeam and the surrounding elastic medium. Influence of all parameters such as nonlocal small-scale effects, Winkler modulus parameter, vibration mode and aspect ratio of nanobeam on the vibration frequency are analyzed and discussed. The mechanical properties of carbon nanotubes and polymer matrix are treated and an analytical solution is derived using the governing equations of the nonlocal Euler-Bernoulli beam models. Solutions have been compared with those obtained in the literature and The results obtained show that the non-dimensional natural frequency is significantly affected by the small-scale coefficient, the vibrational mode number and the elastic medium.

비측정용 카메라의 원격조종에 의한 대축척 지형정보 획득 (Acquisition of Large Scale Geographical Information by Remote Control of Non-Metric Camera)

  • 강준묵;윤희천;배연성
    • 대한공간정보학회지
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    • 제1권2호
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    • pp.177-184
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    • 1993
  • 소규모 지역에 대한 대축척 정밀 지형정보를 경제적으로 얻기 위해 외부표정요소를 정확히 산출하고, 무선조종이 가능한 무인 비행선에 정오차 보정요소를 결정한 35mm 비측정용 카메라를 탑재하여 촬영하였다. 해석에 필요한 지상기준점은 GPS측량으로 상대적 위치를 결정하여 정확도 향상을 기하였다. 또한 해석도화기에 의해 대축척 지형도를 제작하여 정확도 검증을 함으로써 그 응용가능성을 제시하였다.

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진화 연산을 이용한 능동외곽기반의 윤곽선검출에 관한 연구 (Active Contour Based Edge Detection Using Evolutionary Computation)

  • 강현태;조덕환;황기현;문경준;박준호;이화석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 D
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    • pp.2405-2407
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    • 2001
  • In this paper, we apply and evolutionary computation(EC), probabilistic optimization algorithm, to active contour. A number of problems exist associated with such as algorithm initialization, existence of local minima, non-convex search space, and the selection of model parameters in conventional models. We propose an adequate fitness function for these problems. The determination of fitness function adequate to active contour using EC is important in search capability. As a result of applying the proposed method to non-convex object shape, we improve the unstability and contraction phenomena, in nature, of snake generated in deformable contour optimization.

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가변학습율과 온라인모드를 이용한 개선된 EBP 알고리즘 (Improved Error Backpropagation by Elastic Learning Rate and Online Update)

  • Lee, Tae-Seung;Park, Ho-Jin
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (B)
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    • pp.568-570
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    • 2004
  • The error-backpropagation (EBP) algerithm for training multilayer perceptrons (MLPs) is known to have good features of robustness and economical efficiency. However, the algorithm has difficulty in selecting an optimal constant learning rate and thus results in non-optimal learning speed and inflexible operation for working data. This paper Introduces an elastic learning rate that guarantees convergence of learning and its local realization by online upoate of MLP parameters Into the original EBP algorithm in order to complement the non-optimality. The results of experiments on a speaker verification system with Korean speech database are presented and discussed to demonstrate the performance improvement of the proposed method in terms of learning speed and flexibility fer working data of the original EBP algorithm.

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Research Advances on Tension Buckling Behaviour of Aerospace Structures: A Review

  • Datta, Prosun Kumar;Biswas, Sauvik
    • International Journal of Aeronautical and Space Sciences
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    • 제12권1호
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    • pp.1-15
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    • 2011
  • This paper reviews most of the research done in the field of tensile buckling characteristics pertaining to aerospace structural elements with special attention to local buckling and parametric excitation due to periodic loading on plate and shell elements. The concepts of buckling in aerospace structures appear as the result of the application of a global compressive applied load or shear load. A less usual situation is the case, in which a global tensile stress creates buckling instability and the formation of complex spatial buckling pattern. In contrast to the case of a pure compression or shear load, here the applied macroscopic load has no compressive component and is thus globally stabilizing. The instability stems from a local compressive stress induced by the presence of a defect, such as a crack or a hole, due to partial or non-uniform applied load at the far end. This is referred to as tensile buckling. This paper discusses all aspects of tensile buckling, theoretical and experimental. Its far reaching applications causing local instability in aerospace structural components are discussed. The important effects on dynamic stability behaviour under locally induced periodic compression have been identified and influences of various parameters are discussed. Experimental results on simple and combination resonance characteristics on plate structures due to tensile buckling effects are elaborated.

국소 선형 복합 분위수 회귀에서의 평활계수 선택 (Selection of bandwidth for local linear composite quantile regression smoothing)

  • 전명식;강종경;방성완
    • 응용통계연구
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    • 제30권5호
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    • pp.733-745
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    • 2017
  • 국소복합분위수 회귀모형을 활용한 비모수적 함수 추정방법이 높은 효율성과 더불어 활발히 연구되고 있다. 이러한 추정과정에 커널을 사용한 자료 평활방법이 대표적으로 사용되고 있으며, 그 성능은 커널보다는 평활계수의 선택 크게 의존한다. 한편, 회귀함수 추정방법의 성능을 평가하는 기준으로는 통상적으로 $L_2$-노름이 사용되어 평균제곱오차 또는 평균적분제곱오차를 최소화하는 평활계수의 선택에 대한 많은 연구가 진행되어 왔다. 본 논문에서는 국소선형 복합 분위수 회귀방법을 활용한 비모수 회귀모형 추정량의 성능을 결정하는 평활계수 선택의 최적성에 관해 연구하였다. 특히, 여러 장점을 가졌으나 수리적 어려움으로 연구가 미흡한 평균절대오차 및 평균적분절대오차를 최적의 기준으로 삼아 최적의 평활계수를 구하고 그 유일성에 관해 연구하였다. 나아가 기존의 평가기준인 평균제곱오차 및 평균적분제곱오차를 사용한 선택과의 관계를 파악하고 그 성능을 비교하였다. 이러한 과정에서 다양한 상황에서의 모의실험을 통해 제안한 방법의 특성을 규명하였다.

An Experimental Study of Critical Heat Flux in Non-uniformly Heated Vertical Annulus under Low Flow Conditions

  • Chun, Se-Young;Moon, Sang-Ki;Baek, Won-Pil;Chung, Moon-Ki;Masanori Aritomi
    • Journal of Mechanical Science and Technology
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    • 제17권8호
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    • pp.1171-1184
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    • 2003
  • An experimental study on critical heat flux (CHF) has been performed in an internally heated vertical annulus with non-uniform heating. The CHF data for the chopped cosine heat flux have been compared with those for uniform heat flux obtained from the previous study of the authors, in order to investigate the effect of axial heat flux distribution on CHF. The local CHF with the parameters such as mass flux and critical quality shows an irregular behavior. However, the total critical power with mass flux and the average CHF with critical quality are represented by a unique curve without the irregularity. The effect of the heat flux distribution on CHF is large at low pressure conditions but becomes rapidly smaller as the pressure increases. The relationship between the critical quality and the boiling length is represented by a single curve, independent of the axial heat flux distribution. For non-uniform axial heat flux distribution, the prediction results from Doerffer et al.'s and Bowling's CHF correlations have considerably large errors, compared to the prediction for uniform heat flux distribution.

Risk assessment of heavy metals in soil based on the geographic information system-Kriging technique in Anka, Nigeria

  • Johnbull, Onisoya;Abbassi, Bassim;Zytner, Richard G.
    • Environmental Engineering Research
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    • 제24권1호
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    • pp.150-158
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    • 2019
  • Soil contaminated with heavy metals from artisanal gold mining in Anka Local Government Area in Northwestern Nigeria was investigated to evaluate the human health risk as a result of heavy metals. Measured concentration of heavy metals and exposure parameters were used to estimate human carcinogenic and non-carcinogenic risk. GIS-based Kriging method was utilized to create a prediction maps of human health risks and probability maps of heavy metals concentrations exceeding their threshold limits. Hazard index calculation showed that 21 out of 23 locations are posing non-cancer risk for children. Adults and children are at high cancer risk in all locations as the total cancer risk exceeded $1{\times}10^{-6}$ (the lower limit CTR value). Kriging model showed that only a very small area in Anka has a hazard index of less than unity and cumulative target risk of less than $1{\times}10^{-4}$, indicating a significant carcinogenic and non-carcinogenic risks for children. The probability of heavy metals to exceed their threshold concentrations around the study area was also found to be high.