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Border-search and jump reduction method for size optimization of spatial truss structures

Babak DIZANGIAN, Mohammad Reza GHASEMI

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 123-134 doi: 10.1007/s11709-018-0478-2

摘要： This paper proposes a sensitivity-based border-search and jump reduction method for optimum design of spatial trusses. It is considered as a two-phase optimization approach, where at the first phase, the first local optimum is found by few analyses, after the whole searching space is limited employing an efficient random strategy, and the second phase involves finding a sequence of local optimum points using the variables sensitivity with respect to corresponding values of constraints violation. To reach the global solution at phase two, a sequence of two sensitivity-based operators of border-search operator and jump operator are introduced until convergence is occurred. Sensitivity analysis is performed using numerical finite difference method. To do structural analysis, a link between open source software of OpenSees and MATLAB was developed. Spatial truss problems were attempted for optimization in order to show the fastness and efficiency of proposed technique. Results were compared with those reported in the literature. It shows that the proposed method is competitive with the other optimization methods with a significant reduction in number of analyses carried.

关键词： optimum design     sensitivity analysis     reduction method     spatial trusses     OpenSees    

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Strength of tubular welded joints of roof trusses in Shanghai Qizhong Tennis Center

TONG Lewei, GU Min, CHEN Yiyi, ZHOU Liying, SUN Jiandong, CHEN Yangji, LIN Yingru, LIN Gao

《结构与土木工程前沿（英文）》 2008年 第2卷 第1期   页码 30-36 doi: 10.1007/s11709-008-0010-1

摘要： Static strength of multi-planar welded joints with seven brace members and one chord member made of circular hollow sections is investigated in the paper, based on the engineering practice of moveable roof trusses of Shanghai Qizhong Tennis Center. Firstly, comparative experiments were carried out on two model joints with a scale of 1:3. One joint was not reinforced, whereas the other was reinforced with ring stiffeners inside the chord member. Failure mode, stress distribution, plastic-zone development and ultimate load capacity of the joints were investigated, and effects of the ring stiffeners on the joint behavior were observed through the experiments. Secondly, finite element analysis of both the tested model joints was performed. The calculation results are in a good agreement with the experimental results, which indicated that the numerical analysis was quite effective. Finally, the strategy for enhancing strength of the complicated joint is discussed. Parameters study on the constructional details of ring stiffeners was carried out using FE method. The present research shows the multi-planar circular hollow section joint with high ratio of diameter to thickness of the chord and multiple braces is liable to chord plasticity under axial tension and compression on the braces. For the design of the joint, it is suggested that the ring stiffeners are installed insider the chord to meet needs of enough stiffness and strength. Both position and number of the stiffeners should be carefully determined based on the axial forces on the braces and their diameters. The stiffener thickness should not be less than the chord thickness, and the diameter of the hole at the center of the stiffener should not be greater than half of the chord diameter.

关键词： diameter     numerical analysis     calculation     thickness     engineering    

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Soil spatial variability impact on the behavior of a reinforced earth wall

Adam HAMROUNI, Daniel DIAS, Badreddine SBARTAI

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 518-531 doi: 10.1007/s11709-020-0611-x

摘要： This article presents the soil spatial variability effect on the performance of a reinforced earth wall. The serviceability limit state is considered in the analysis. Both cases of isotropic and anisotropic non-normal random fields are implemented for the soil properties. The Karhunen-Loève expansion method is used for the discretization of the random field. Numerical finite difference models are considered as deterministic models. The Monte Carlo simulation technique is used to obtain the deformation response variability of the reinforced soil retaining wall. The influences of the spatial variability response of the geotechnical system in terms of horizontal facing displacement is presented and discussed. The results obtained show that the spatial variability has an important influence on the facing horizontal displacement as well as on the failure probability.

关键词： reinforced earth wall     geosynthetic     random field     spatial variability     Monte Carlo simulation    

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Industrial eco-efficiency and its spatial-temporal differentiation in China

Wei YANG, Fengjun JIN, Chengjin WANG, Chen LV

《环境科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 559-568 doi: 10.1007/s11783-012-0400-4

摘要： The aim of this paper is to study the spatial-temporal differentiation of industrial eco-efficiency in China. Using methods based on the data envelopment analysis (DEA) model and exploratory spatial data analysis (ESDA) and data from 1985, 1995, 2005, and 2008 of 30 provinces in China, the spatial-temporal pattern changes in industrial eco-efficiency are discussed. The results show that: first, the patterns of industrial eco-efficiency are dominated by clustering of relatively low efficiency provinces; second, spatial relationships between the industrial eco-efficiencies of different provinces changed slightly throughout the period and the provinces persistently exhibit spatial concentration of relatively low industrial eco-efficiency; finally, there is an obvious trend in the polarization of industrial eco-efficiency, i.e., the higher level spatial units are concentrated in eastern China, and the lower level spatial units are mainly in western and central China.

关键词： industrial eco-efficiency     data envelopment analysis (DEA) model     exploratory spatial data analysis (ESDA)    

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Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1724-y

摘要： Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.

关键词： Microplastic     Environmental transport     Soil pollution     Stormwater     Detention ponds    

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Spatial prediction of soil contamination based on machine learning: a review

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1693-1

摘要：

● A review of machine learning (ML) for spatial prediction of soil contamination.

关键词： Soil contamination     Machine learning     Prediction     Spatial distribution    

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Optimization of spatial structure designs of control rod using Monte Carlo code RMC

《能源前沿（英文）》 2021年 第15卷 第4期   页码 974-983 doi: 10.1007/s11708-021-0769-5

摘要： Control rod is the most important approach to control reactivity in reactors, which is currently a cluster of pins filled with boron carbide (B4C). In this case, neutrons are captured in the outer region, and thus the inner absorber is inefficient. Moreover, the lifetime of the control rod is challenged due to the high reactivity worth loss resulted from the excessive degradation of B4C in the high flux area. In this work, some control rod designs are proposed with optimized spatial structures including the spatially mixed rod, radially moderated rod, and composite control rod with small-sized pins. The control rod worth and effective absorption cross section of these designs are computed using the Monte Carlo code RMC. A long-time depletion calculation is conducted to evaluate their burnup stability. For the spatially mixed rod, rare-earth absorbers are combined with B4C in spatial structure. Compared with the homogenous B4C rod, mixed designs ensure more sufficient reactivity worth in the lifetime of the reactor. The minimum reactivity loss at the end of the cycle is only 1.8% from the dysprosium titanate rod, while the loss for pure B4C rod is nearly 12%. For the radially moderated design, a doubled neutronic efficiency is achieved when the volume ratio of moderator equals approximately 0.3, while excessive moderating may lead to the failure of control rods. The control rod with small-sized pins processes an enhanced safety performance and saves the investment in absorbers. The rod worth can be further enhanced by introducing small moderator pins, and the reactivity loss caused by the reduction of absorbers is sustainable.

关键词： control rod     optimized spatial structure     neutronic performance     burnup stability    

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Differences in distributions, assembly mechanisms, and putative interactions of AOB and NOB at a large spatial

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1722-0

摘要：

● Nitrifiers in WWTP were investigated at large spatial scale.

关键词： Activated sludge     Spatial distributions     Microbial assembly     Co-occurrence patterns     Nitrifying bacteria    

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Application of cable-supported spatial grid in dry coal shed

XING Haidong, HAO Jiping, XU Guobin

《结构与土木工程前沿（英文）》 2008年 第2卷 第1期   页码 26-29 doi: 10.1007/s11709-008-0008-8

摘要： This paper presented a new structural style cable-supported spatial grid, which was applied in large span dry coal sheds. The influence of configuration of cable on the force of cable and beam, the ratio of beam force to cable force and the deflection of span was investigated, and a rational configuration of cable was obtained. The results show that the cable-supported spatial grid can maximize the use of material strength, and have the advantages of low usage of steel, large span and sufficient headroom.

关键词： dry     material strength     low     rational configuration     influence    

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PyLUR: Efficient software for land use regression modeling the spatial distribution of air pollutants

Xuying Ma, Ian Longley, Jennifer Salmond, Jay Gao

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1221-5

摘要： PyLUR comprises four modules for developing and applying a LUR model. It considers both conventional and novel potential predictor variables. GDAL/OGR libraries are used to do spatial analysis in the modeling and prediction. Developed on Python platform, PyLUR is rather efficient in data processing. Land use regression (LUR) models have been widely used in air pollution modeling. This regression-based approach estimates the ambient pollutant concentrations at un-sampled points of interest by considering the relationship between ambient concentrations and several predictor variables selected from the surrounding environment. Although conceptually quite simple, its successful implementation requires detailed knowledge of the area, expertise in GIS, statistics, and programming skills, which makes this modeling approach relatively inaccessible to novice users. In this contribution, we present a LUR modeling and pollution-mapping software named PyLUR. It uses GDAL/OGR libraries based on the Python platform and can build a LUR model and generate pollutant concentration maps efficiently. This self-developed software comprises four modules: a potential predictor variable generation module, a regression modeling module, a model validation module, and a prediction and mapping module. The performance of the newly developed PyLUR is compared to an existing LUR modeling software called RLUR (with similar functions implemented on R language platform) in terms of model accuracy, processing efficiency and software stability. The results show that PyLUR out-performs RLUR for modeling in the Bradford and Auckland case studies examined. Furthermore, PyLUR is much more efficient in data processing and it has a capability to handle detailed GIS input data.

关键词： LUR     Air pollution modelling     GIS spatial analysis     GDAL/OGR Python     Pollutant concentration mapping    

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Animage-based approach to the reconstruction of ancient architectures by extracting and arranging 3D spatial

Divya Udayan J,HyungSeok KIM,Jee-In KIM

《信息与电子工程前沿（英文）》 2015年 第16卷 第1期   页码 12-27 doi: 10.1631/FITEE.1400141

摘要： The objective of this research is the rapid reconstruction of ancient buildings of historical importance using a single image. The key idea of our approach is to reduce the infinite solutions that might otherwise arise when recovering a 3D geometry from 2D photographs. The main outcome of our research shows that the proposed methodology can be used to reconstruct ancient monuments for use as proxies for digital effects in applications such as tourism, games, and entertainment, which do not require very accurate modeling. In this article, we consider the reconstruction of ancient Mughal architecture including the Taj Mahal. We propose a modeling pipeline that makes an easy reconstruction possible using a single photograph taken from a single view, without the need to create complex point clouds from multiple images or the use of laser scanners. First, an initial model is automatically reconstructed using locally fitted planar primitives along with their boundary polygons and the adjacency relation among parts of the polygons. This approach is faster and more accurate than creating a model from scratch because the initial reconstruction phase provides a set of structural information together with the adjacency relation, which makes it possible to estimate the approximate depth of the entire structural monument. Next, we use manual extrapolation and editing techniques with modeling software to assemble and adjust different 3D components of the model. Thus, this research opens up the opportunity for the present generation to experience remote sites of architectural and cultural importance through virtual worlds and real-time mobile applications. Variations of a recreated 3D monument to represent an amalgam of various cultures are targeted for future work.

关键词： Digital reconstruction     3D virtual world     3D spatial components     Vision and scene understanding    

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Quantifying and mapping spatial variability of Shanghai household carbon footprints

Shangguang YANG,Chunlan WANG,Kevin LO,Mark WANG,Lin LIU

《能源前沿（英文）》 2015年 第9卷 第1期   页码 115-124 doi: 10.1007/s11708-015-0348-8

摘要： Understanding the spatial variability of household carbon emissions is necessary for formulating sustainable and low-carbon energy policy. However, data on household carbon emissions is limited in China, the world’s largest greenhouse gases emitter. This study quantifies and maps household carbon emissions in Shanghai using a city-wide household survey. The findings reveal substantial spatial variability in household carbon emissions, especially in transport-related emissions. Low emission clusters are founded in Hongkou, Xuhui, Luwan, Jinshan, and Fengxian. High emission clusters are located in Jiading and Pudong. Overall, the spatial pattern of household carbon emissions in Shanghai is donut-shaped: lowest in the urban core, increasing in the surrounding suburban areas, and declining again in the urban fringe and rural regions. The household emissions are correlated with a number of housing and socioeconomic factors, including car ownership, type of dwelling, size of dwelling, age of dwelling, and income. The findings underscore the importance of a localized approach to low-carbon policy-making and implementation.

关键词： household carbon emissions     spatial variability     energy policy     Shanghai     China    

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基于高速交通网络的秦巴山脉地区空间格局研究

武廷海,张能

《中国工程科学》 2016年 第18卷 第5期   页码 52-59 doi: 10.15302/J-SSCAE-2016.05.008

摘要：

改善通达性是秦巴山脉地区扶贫开发和实现可持续发展的重要手段。本文根据《国家公路网规划(2013年—2030年)》与《中长期铁路网规划》中确定的高速交通网络，研究秦巴山脉地区及周边城市群地区中心城市的可达性，进而模拟秦巴山脉地区的空间格局。研究发现，随着国家规划高速交通网络的建设，秦巴山脉地区将形成以西安为中心的西安—万州、西安—襄阳、西安—洛阳三条放射型主要城市走廊，以及西安—天水、西安—广元、达州—襄阳—南阳—洛阳三条次要城市走廊。受其城市走廊的影响，秦巴山脉地区将形成以陇南、巴中、十堰、栾川为核心的四个巨型绿野。本文建议，未来的秦巴山脉地区空间规划，在努力发挥秦巴山脉地区对周边城市群地区生态平衡作用的同时，要自觉建立秦巴山脉地区内部的空间秩序，合理安排城市走廊与巨型绿野，实现保护与发展的平衡。

关键词： 秦巴山脉地区     空间格局     高速交通网络     空间规划     城市走廊     巨型绿野    

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Instrumented toys for assessing spatial cognition in infants

Domenico CAMPOLO, Fabrizio TAFFONI, Domenico FORMICA, Flavio KELLER, Eugenio GUGLIELMELLI

《机械工程前沿（英文）》 2011年 第6卷 第1期   页码 82-88 doi: 10.1007/s11465-011-0208-0

摘要：

This paper describes an interdisciplinary approach to the assessment on infants’ behavior, with a focus on the technology. The goal is an objective, quantitative analysis of concurrent maturation of sensory, motor and cognitive abilities in young children, in relation to the achievement of developmental milestones. An instrumented block-box toy specifically developed to assess the ability to insert objects into holes is presented. The functional specifications are derived from experimental protocols devised by neuroscientists to assess spatial cognition skills. Technological choices are emphasized with respect to ecological requirements. An ad hoc calibration procedure is also presented which is suitable to unstructured environments. Finally, preliminary tests carried out at a local day-care with 12–24 months old infants are presented which prove the in-field usability of the proposed technology.

关键词： inertial-magnetic sensing     in-field calibration     neuro-developmental engineering     ecological assessment    

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Novel decoupled framework for reliability-based design optimization of structures using a robust shifting technique

Mohammad Reza GHASEMI, Charles V. CAMP, Babak DIZANGIAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第4期   页码 800-820 doi: 10.1007/s11709-019-0517-7

摘要： In a reliability-based design optimization (RBDO), computation of the failure probability ( ) at all design points through the process may suitably be avoided at the early stages. Thus, to reduce extensive computations of RBDO, one could decouple the optimization and reliability analysis. The present work proposes a new methodology for such a decoupled approach that separates optimization and reliability analysis into two procedures which significantly improve the computational efficiency of the RBDO. This technique is based on the probabilistic sensitivity approach (PSA) on the shifted probability density function. Stochastic variables are separated into two groups of desired and non-desired variables. The three-phase procedure may be summarized as: Phase 1, apply deterministic design optimization based on mean values of random variables; Phase 2, move designs toward a reliable space using PSA and finding a primary reliable optimum point; Phase 3, applying an intelligent self-adaptive procedure based on cubic B-spline interpolation functions until the targeted failure probability is reached. An improved response surface method is used for computation of failure probability. The proposed RBDO approach could significantly reduce the number of analyses required to less than 10% of conventional methods. The computational efficacy of this approach is demonstrated by solving four benchmark truss design problems published in the structural optimization literature.

关键词： reliability-based design optimization     trusses     sensitivity analysis     shifting technique     cubic B-splines     response surface method    

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标题 作者 时间 类型 操作

Border-search and jump reduction method for size optimization of spatial truss structures

Babak DIZANGIAN, Mohammad Reza GHASEMI

期刊论文

Strength of tubular welded joints of roof trusses in Shanghai Qizhong Tennis Center

TONG Lewei, GU Min, CHEN Yiyi, ZHOU Liying, SUN Jiandong, CHEN Yangji, LIN Yingru, LIN Gao

期刊论文

Soil spatial variability impact on the behavior of a reinforced earth wall

Adam HAMROUNI, Daniel DIAS, Badreddine SBARTAI

期刊论文

Industrial eco-efficiency and its spatial-temporal differentiation in China

Wei YANG, Fengjun JIN, Chengjin WANG, Chen LV

期刊论文

Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

期刊论文

Spatial prediction of soil contamination based on machine learning: a review

期刊论文

Optimization of spatial structure designs of control rod using Monte Carlo code RMC

期刊论文

Differences in distributions, assembly mechanisms, and putative interactions of AOB and NOB at a large spatial

期刊论文

Application of cable-supported spatial grid in dry coal shed

XING Haidong, HAO Jiping, XU Guobin

期刊论文

PyLUR: Efficient software for land use regression modeling the spatial distribution of air pollutants

Xuying Ma, Ian Longley, Jennifer Salmond, Jay Gao

期刊论文

Animage-based approach to the reconstruction of ancient architectures by extracting and arranging 3D spatial

Divya Udayan J,HyungSeok KIM,Jee-In KIM

期刊论文

Quantifying and mapping spatial variability of Shanghai household carbon footprints

Shangguang YANG,Chunlan WANG,Kevin LO,Mark WANG,Lin LIU

期刊论文

基于高速交通网络的秦巴山脉地区空间格局研究

武廷海,张能

期刊论文

Instrumented toys for assessing spatial cognition in infants

Domenico CAMPOLO, Fabrizio TAFFONI, Domenico FORMICA, Flavio KELLER, Eugenio GUGLIELMELLI

期刊论文

Novel decoupled framework for reliability-based design optimization of structures using a robust shifting technique

Mohammad Reza GHASEMI, Charles V. CAMP, Babak DIZANGIAN

期刊论文