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Beyond bag of latent topics: spatial pyramid matching for scene category recognition

Fu-xiang LU,Jun HUANG

《信息与电子工程前沿(英文)》 2015年 第16卷 第10期   页码 817-828 doi: 10.1631/FITEE.1500070

摘要: We propose a heterogeneous, mid-level feature based method for recognizing natural scene categories. The proposed feature introduces spatial information among the latent topics by means of spatial pyramid, while the latent topics are obtained by using probabilistic latent semantic analysis (pLSA) based on the bag-of-words representation. The proposed feature always performs better than standard pLSA because the performance of pLSA is adversely affected in many cases due to the loss of spatial information. By combining various interest point detectors and local region descriptors used in the bag-of-words model, the proposed feature can make further improvement for diverse scene category recognition tasks. We also propose a two-stage framework for multi-class classification. In the first stage, for each of possible detector/descriptor pairs, adaptive boosting classifiers are employed to select the most discriminative topics and further compute posterior probabilities of an unknown image from those selected topics. The second stage uses the prod-max rule to combine information coming from multiple sources and assigns the unknown image to the scene category with the highest ‘final’ posterior probability. Experimental results on three benchmark scene datasets show that the proposed method exceeds most state-of-the-art methods.

关键词: Scene category recognition     Probabilistic latent semantic analysis     Bag-of-words     Adaptive boosting    

Risk-based probabilistic thermal-stress analysis of concrete arch dams

Narjes SOLTANI, Mohammad ALEMBAGHERI, Mohammad Houshmand KHANEGHAHI

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1007-1019 doi: 10.1007/s11709-019-0521-y

摘要: The probabilistic risk of arch dam failure under thermal loading is studied. The incorporated uncertainties, which are defined as random variables, are associated with the most affecting structural (material) properties of concrete and thermal loading conditions. Karaj arch dam is selected as case study. The dam is numerically modeled along with its foundation in three-dimensional space; the temperature and thermal stress distribution is investigated during the operating phase. The deterministic thermal finite element analysis of the dam is combined with the structural reliability methods in order to obtain thermal response predictions, and estimate the probability of failure in the risk analysis context. The tensile overstressing failure mode is considered for the reliability analysis. The thermal loading includes ambient air and reservoir temperature variations. The effect of solar radiation is considered by an increase in the ambient temperatures. Three reliability methods are employed: the first-order second-moment method, the first-order reliability method, and the Monte-Carlo simulation with Latin Hypercube sampling. The estimated failure probabilities are discussed and the sensitivity of random variables is investigated. Although most of the studies in this line of research are used only for academic purposes, the results of this investigation can be used for both academic and engineering purposes.

关键词: arch dams     probabilistic analysis     thermal stress     sensitivity     reliability    

Probabilistic analysis of secant piles with random geometric imperfections

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 682-695 doi: 10.1007/s11709-021-0703-2

摘要: The failure to achieve minimum design overlap between secant piles compromises the ability of a structure to perform as designed, resulting in water leakage or even ground collapse. To establish a more realistic simulation and provide guidelines for designing a safe and cost-effective secant-pile wall, a three-dimensional model of a secant pile, considering the geometric imperfections of the diameter and direction of the borehole, is introduced. An ultrasonic cross-hole test was performed during the construction of secant piles in a launching shaft in Beijing, China. Based on the test results, the statistical characteristics of the pile diameters and orientation parameters were obtained. By taking the pile diameter D, inclination angle β, and azimuth angle α as random variables, Monte Carlo simulations were performed to discuss the influence of different design parameters on the probability density functions of the overlap of secant piles. The obtained results show that the randomness of the inclination angle and pile diameter can be well described by a normal distribution, whereas the azimuth angle is more consistent with a uniform distribution. The integrity of the secant-pile wall can be overestimated without considering the uncertainty of geometric imperfections. The failure of the secant-pile wall increases substantially with increasing spatial variability in drilling inclination and diameter. A design flowchart for pile spacing under the target safety level is proposed to help engineers design a safe and economical pile wall.

关键词: secant piles     ultrasonic cross-hole testing     probabilistic analysis     reliability-based design     random imperfections    

Seismic performance of viaducts with probabilistic method

ZHU Xi, WANG Jianmin

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 267-273 doi: 10.1007/s11709-007-0034-y

摘要: Due to the uncertainty of both ground motions and structural capacity, it is necessary to consider the seismic performance of viaduct structures using the probabilistic method. The risk is quantified by a procedure on the basis of a numerical determination of the fragility curves. A group of ground motions, Large Magnitude-Short Distance Bin (LMSR-N), selected specially due to its response spectra, is accorded well with the corresponding spectra of the Chinese code for seismic design. The characteristic values of the curvature ductility factors for the serviceability and the damage control limit states are obtained, and two equations for estimating the characteristic values of the curvature ductility factors are developed through regression analysis. Then, the serviceability and damage control limit states were proposed. Three damage states were constituted according the results of the experiment by Pacific Earthquake Engineering Research (PEER) Center. The analytical fragility curves were obtained specifically, using both Capacity Spectrum Method (CSM) (non-linear static) analysis and Ineremental Dynamic Method (IDM) (non-linear dynamic) analysis, respectively, in this paper. The structural fragility curves developed by CSM method can help make the structural analysis simple and quick, avoiding the implementation of the dynamic response history analysis (RHA). Although the dynamic RHA requires a lot of complicated analysis for the structure, the results from RHA are reliable and accurate. Fragility curves are powerful tools for use in performance-based seismic bridge design.

关键词: uncertainty     Earthquake Engineering     regression analysis     accurate     fragility    

Application of probabilistic risk assessment at a coking plant site contaminated by Polycyclic Aromatic

XIA Tianxiang,JIANG Lin,JIA Xiaoyang,ZHONG Maosheng,LIANG Jing

《环境科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 441-450 doi: 10.1007/s11783-013-0572-6

摘要: Application of Probabilistic Risk Assessment (PRA) and Deterministic Risk Assessment (DRA) at a coking plant site was compared. By DRA, Hazard Quotient (HQ) following exposure to Naphthalene (Nap) and Incremental Life Cancer Risk (ILCR) following exposure to Benzo(a)pyrene (Bap) were 1.87 and 2.12 × 10 . PRA revealed valuable information regarding the possible distribution of risk, and risk estimates of DRA located at the 99.59th and 99.76th percentiles in the risk outputs of PRA, which indicated that DRA overestimated the risk. Cleanup levels corresponding acceptable HQ level of 1 and ILCR level of 10 were also calculated for both DRA and PRA. Nap and Bap cleanup levels were 192.85 and 0.14 mg·kg by DRA, which would result in only 0.25% and 0.06% of the exposed population to have a risk higher than the acceptable risk, according to the outputs of PRA. The application of PRA on cleanup levels derivation would lift the cleanup levels 1.9 times for Nap and 2.4 times for Bap than which derived by DRA. For this coking plant site, the remediation scale and cost will be reduced in a large portion once the method of PRA is used. Sensitivity analysis was done by calculating the contribution to variance for each exposure parameter and it was found that contaminant concentration in the soil ( ), exposure duration ( ), total hours spent outdoor per day ( ), soil ingestion rate ( ), the air breathing rate ( ) and bodyweight ( ) were the most important parameters for risk and cleanup levels calculations.

关键词: Probabilistic Risk Assessment (PRA)     a coking plant     risk     cleanup level     sensitivity analysis     polycyclic aromatic hydrocarbons (PAHs)    

An interval joint-probabilistic programming method for solid waste management: a case study for the city

Yi XU, Shunze WU, Hongkuan ZANG, Guiguang HOU

《环境科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 239-255 doi: 10.1007/s11783-013-0536-x

摘要: Currently, environmental protection and resources conservation continue to be challenges faced by solid-waste managers in China. These challenges are being further compounded by rapid socioeconomic development and population growth associated with increased waste generation rates and decreased waste disposal capacities. In response to these challenges, an interval joint-probabilistic mixed-integer programming (IJMP) method is developed for supporting long-term planning of waste management activities in the city of Tianjin, which is one of the largest municipalities in the northern part of China. In the IJMP, joint probabilistic constraints are introduced into an interval-parameter mixed-integer programming framework, such that uncertainties presented in terms of interval values and random variables can be reflected. Moreover, a number of violation levels for the waste-management-capacity constraints are examined, which can facilitate in-depth analyses of tradeoffs among economic objective and system-failure risk. The results indicate that reasonable solutions have been generated. They are valuable for supporting the adjustment of the city’s existing waste-management practices and the long-term planning of the city’s waste-management facilities.

关键词: interval analysis     mixed integer     joint probabilistic constraint     planning     uncertainty     waste management    

Proposal of a probabilistic assessment of structural collapse concomitantly subject to earthquake and

Gholamreza ABDOLLAHZADEH, Hadi FAGHIHMALEKI

《结构与土木工程前沿(英文)》 2018年 第12卷 第3期   页码 425-437 doi: 10.1007/s11709-017-0427-5

摘要:

In recent decades, many public buildings, located in seismic-prone residential areas, had to grapple with abnormal loads against which the structures were unguarded. In this piece of research, an ordinary three dimensional reinforced concrete building is selected as case study. The building is located in an earthquake-prone region; however, it is designed according to seismic building codes. Yet, it is not shielded against abnormal loads, such as blasts. It is assumed that the building suffers a blast load, due to mechanical/thermal installation failure during or after intense seismic oscillations. These two critical incidents are regarded codependent and compatible. So the researchers developed scenarios and tried to assess different probabilities for each scenario and carried out an analysis to ensure if progressive collapse had set in or not. In the first step, two analysis models were used for each scenario; a non-linear dynamic time history analysis and a blast local dynamic analysis. In the second step, having the structural destructions of the first step in view, a pushdown analysis was carried out to determine the severity of progressive collapse and assess building robustness. Finally, the annual probability of structural collapse under simultaneous earthquake and blast loads was estimated and offered.

关键词: gas blast     pushdown analysis     progressive collapse     annual probability of structural collapse     3D model of structure    

Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermal

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1038-1050 doi: 10.1007/s11705-022-2279-3

摘要: Phase change materials are potential candidates for the application of latent heat storage. Herein, we fabricated porous capsules as shape-stable materials from cellulose-based polyelectrolyte complex, which were first prepared using cellulose 6-(N-pyridinium)hexanoyl ester as the cationic polyelectrolyte and carboxymethyl cellulose as the anionic polyelectrolyte to encapsulate polyethylene glycol by the vacuum impregnation method. Furthermore, the multi-walled carbon nanotube or graphene oxide, which were separately composited into the polyelectrolytes complex capsules to enhance thermal conductivity and light-to-thermal conversion efficiency. These capsules owned a typical core–shell structure, with an extremely high polyethylene glycol loading up to 34.33 g∙g‒1. After loading of polyethylene glycol, the resulted cellulose-based composite phase change materials exhibited high thermal energy storage ability with the latent heat up to 142.2 J∙g‒1, which was 98.5% of pure polyethylene glycol. Further results showed that the composite phase change materials demonstrated good form-stable property and thermal stability. Moreover, studies involving light-to-thermal conversion determined that composite phase change materials exhibited outstanding light-to-thermal conversion performance. Considering their exceptional comprehensive features, innovative composite phase change materials generated from cellulose presented a highly interesting choice for thermal management and renewable thermal energy storage.

关键词: cellulose     polyelectrolytes     phase change materials     thermal energy storage     light-to-thermal conversion    

Fast detection algorithm for cracks on tunnel linings based on deep semantic segmentation

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 732-744 doi: 10.1007/s11709-023-0965-y

摘要: An algorithm based on deep semantic segmentation called LC-DeepLab is proposed for detecting the trends and geometries of cracks on tunnel linings at the pixel level. The proposed method addresses the low accuracy of tunnel crack segmentation and the slow detection speed of conventional models in complex backgrounds. The novel algorithm is based on the DeepLabv3+ network framework. A lighter backbone network was used for feature extraction. Next, an efficient shallow feature fusion module that extracts crack features across pixels is designed to improve the edges of crack segmentation. Finally, an efficient attention module that significantly improves the anti-interference ability of the model in complex backgrounds is validated. Four classic semantic segmentation algorithms (fully convolutional network, pyramid scene parsing network, U-Net, and DeepLabv3+) are selected for comparative analysis to verify the effectiveness of the proposed algorithm. The experimental results show that LC-DeepLab can accurately segment and highlight cracks from tunnel linings in complex backgrounds, and the accuracy (mean intersection over union) is 78.26%. The LC-DeepLab can achieve a real-time segmentation of 416 × 416 × 3 defect images with 46.98 f/s and 21.85 Mb parameters.

关键词: tunnel engineering     crack segmentation     fast detection     DeepLabv3+     feature fusion     attention mechanism    

Novel probabilistic rolling regular tetrahedron mechanism

Yonghan GUAN, Yan’an YAO, Chao LIU, Ruiming LI

《机械工程前沿(英文)》 2021年 第16卷 第2期   页码 363-378 doi: 10.1007/s11465-020-0628-9

摘要: With recent relevant publications on stochastic motion robots in , , and other journals, research on such robots has gained increasing attention. However, theoretical and applied research on stochastic motion in the field of robotics and mechanisms face many challenges due to the uncertainty of stochastic motion. Currently, a large gap remains in the research of stochastic motion mechanism. In this study, a novel mechanism that can conduct probabilistic rolling is proposed to reach a designated position and achieve overlying movement over a particular area. The mechanism consists of a regular tetrahedron frame, a central node, and four connecting linear actuators. According to mobility and kinematic analyses, the mechanism can implement probabilistic rolling. Each rolling gait has three probable rolling directions, and the mechanism rolls in one of the three directions in probability. A kinematic simulation is conducted, and a control method is proposed on the basis of the moving path analysis. Furthermore, the mathematical principle of probabilistic rolling is revealed in terms of probability theory and statistics. Lastly, a prototype is fabricated. To achieve the rolling function, the design of the linear actuators is improved, and the extension ratio is increased from 0.58 to 1.13. Then, tests are conducted. In a 4 m test site, the mechanism makes 11 moves to reach the target position and covers 29.25% of the site.

关键词: mobile mechanism     probabilistic motion     rolling mechanism     stochastic motion    

Optimal CNN-based semantic segmentation model of cutting slope images

Mansheng LIN; Shuai TENG; Gongfa CHEN; Jianbing LV; Zhongyu HAO

《结构与土木工程前沿(英文)》 2022年 第16卷 第4期   页码 414-433 doi: 10.1007/s11709-021-0797-6

摘要: This paper utilizes three popular semantic segmentation networks, specifically DeepLab v3+, fully convolutional network (FCN), and U-Net to qualitively analyze and identify the key components of cutting slope images in complex scenes and achieve rapid image-based slope detection. The elements of cutting slope images are divided into 7 categories. In order to determine the best algorithm for pixel level classification of cutting slope images, the networks are compared from three aspects: a) different neural networks, b) different feature extractors, and c) 2 different optimization algorithms. It is found that DeepLab v3+ with Resnet18 and Sgdm performs best, FCN 32s with Sgdm takes the second, and U-Net with Adam ranks third. This paper also analyzes the segmentation strategies of the three networks in terms of feature map visualization. Results show that the contour generated by DeepLab v3+ (combined with Resnet18 and Sgdm) is closest to the ground truth, while the resulting contour of U-Net (combined with Adam) is closest to the input images.

关键词: slope damage     image recognition     semantic segmentation     feature map     visualizations    

Construction and humoral immune response of Epstein-Barr virus latent membrane protein 2 DNA vaccine

Jianqing PAN PhD, Qin ZHANG MD, Daowen WANG MD, PhD,

《医学前沿(英文)》 2009年 第3卷 第4期   页码 390-395 doi: 10.1007/s11684-009-0087-5

摘要: We constructed a eukaryotic expression plasmid encoding Epstein-Barr virus latent membrane protein 2 (EBV, LMP2) and evaluated its effects on humoral immunity. First, the encoding sequence of the EBV was amplified from B95−8 cell RNA by reverse transcription polymerase chain reaction (RT-PCR) and then was directionally cloned into eukaryotic expression vector pcDNA3.1. It was employed to evaluate immune response of the mice inoculated doubly with the DNA vaccine. The serum antibody against LMP2 was detected with enzyme-linked immunosorbent assay (ELISA). The recombinant plasmid pcDNA3.1- was confirmed by the restrictive endonuclease analysis and sequence analysis. The serum titer of IgG antibody against LMP2 epitope in the mice immunized with the DNA vaccine encoding LMP2 was up to 1∶4000. In conclusion, the EBV DNA vaccine can induce a strong humoral immune response in mice.

关键词: Epstein-Barr virus     latent membrane protein 2     nasopharyngeal carcinoma     humoral immunity    

基于分布式表示语义组合的查询子主题挖掘 None

Wei SONG, Ying LIU, Li-zhen LIU, Han-shi WANG

《信息与电子工程前沿(英文)》 2018年 第19卷 第11期   页码 1409-1419 doi: 10.1631/FITEE.1601476

摘要: 推断查询意图对于信息检索具有重要意义。查询子主题挖掘旨在找到可能的子主题,用于表示给定查询的潜在意图。由于查询较短,子主题挖掘具有挑战性。学习词或句子分布式表示推动和影响了很多领域的发展。然而,没有清晰的结论表明该分布式表示是否有助于应对查询子主题挖掘面临的挑战。提出并比较利用分布式表示的语义组合进行查询子主题挖掘。采用两种分布式表示策略:能学习任意长度文本分布式表示的段落向量(paragraph vector)以及词向量的语义组合。探索了语义组合策略和数据类型对查询表示的影响。在国家信息学研究所信息获取研究试验平台和社区(National Institute of Informatics Testbeds and Community for Information Access Research,NTCIR)提供的公开数据集上的实验结果表明,与传统语义表示相比,分布式语义表示能获得更优查询子主题挖掘性能。文中做了更多深入探讨。

关键词: 查询子主题挖掘;查询意图;分布式表示;语义组合    

Diagnostic criteria of latent autoimmune diabetes in adults (LADA): a review and reflection

Yu Liao, Yufei Xiang, Zhiguang Zhou

《医学前沿(英文)》 2012年 第6卷 第3期   页码 243-247 doi: 10.1007/s11684-012-0201-y

摘要: Diabetes has become a major public health problem in China nowadays. There are almost 97 million diabetic patients nationwide. Latent autoimmune diabetes in adults (LADA) is a subtype of autoimmune diabetes. Although it has been reported for about 20 years, the diagnostic criteria of this disease remain controversial. The discussion mainly focused on serum autoantibodies, period of insulin need and age of diagnosis. Besides, β cell function, metabolic parameters, genetic factors and cell immunity may also contribute to the formulation of the criteria. Here, we aim to review and discuss the diagnostic criteria of latent autoimmune diabetes in adults.

关键词: LADA     diagnostic criteria     autoantibodies     insulin independence     age of diagnosis    

Probabilistic seismic response and uncertainty analysis of continuous bridges under near-fault ground

Hai-Bin MA, Wei-Dong ZHUO, Davide LAVORATO, Camillo NUTI, Gabriele FIORENTINO, Giuseppe Carlo MARANO, Rita GRECO, Bruno BRISEGHELLA

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1510-1519 doi: 10.1007/s11709-019-0577-8

摘要: Performance-based seismic design can generate predictable structure damage result with given seismic hazard. However, there are multiple sources of uncertainties in the seismic design process that can affect desired performance predictability. This paper mainly focuses on the effects of near-fault pulse-like ground motions and the uncertainties in bridge modeling on the seismic demands of regular continuous highway bridges. By modeling a regular continuous bridge with OpenSees software, a series of nonlinear dynamic time-history analysis of the bridge at three different site conditions under near-fault pulse-like ground motions are carried out. The relationships between different Intensity Measure (IM) parameters and the Engineering Demand Parameter (EDP) are discussed. After selecting the peak ground acceleration as the most correlated IM parameter and the drift ratio of the bridge column as the EDP parameter, a probabilistic seismic demand model is developed for near-fault earthquake ground motions for 3 different site conditions. On this basis, the uncertainty analysis is conducted with the key sources of uncertainty during the finite element modeling. All the results are quantified by the “swing” base on the specific distribution range of each uncertainty parameter both in near-fault and far-fault cases. All the ground motions are selected from PEER database, while the bridge case study is a typical regular highway bridge designed in accordance with the Chinese Guidelines for Seismic Design of Highway Bridges. The results show that PGA is a proper IM parameter for setting up a linear probabilistic seismic demand model; damping ratio, pier diameter and concrete strength are the main uncertainty parameters during bridge modeling, which should be considered both in near-fault and far-fault ground motion cases.

关键词: continuous bridge     probabilistic seismic demand model     Intensity Measure     near-fault     uncertainty    

标题 作者 时间 类型 操作

Beyond bag of latent topics: spatial pyramid matching for scene category recognition

Fu-xiang LU,Jun HUANG

期刊论文

Risk-based probabilistic thermal-stress analysis of concrete arch dams

Narjes SOLTANI, Mohammad ALEMBAGHERI, Mohammad Houshmand KHANEGHAHI

期刊论文

Probabilistic analysis of secant piles with random geometric imperfections

期刊论文

Seismic performance of viaducts with probabilistic method

ZHU Xi, WANG Jianmin

期刊论文

Application of probabilistic risk assessment at a coking plant site contaminated by Polycyclic Aromatic

XIA Tianxiang,JIANG Lin,JIA Xiaoyang,ZHONG Maosheng,LIANG Jing

期刊论文

An interval joint-probabilistic programming method for solid waste management: a case study for the city

Yi XU, Shunze WU, Hongkuan ZANG, Guiguang HOU

期刊论文

Proposal of a probabilistic assessment of structural collapse concomitantly subject to earthquake and

Gholamreza ABDOLLAHZADEH, Hadi FAGHIHMALEKI

期刊论文

Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermal

期刊论文

Fast detection algorithm for cracks on tunnel linings based on deep semantic segmentation

期刊论文

Novel probabilistic rolling regular tetrahedron mechanism

Yonghan GUAN, Yan’an YAO, Chao LIU, Ruiming LI

期刊论文

Optimal CNN-based semantic segmentation model of cutting slope images

Mansheng LIN; Shuai TENG; Gongfa CHEN; Jianbing LV; Zhongyu HAO

期刊论文

Construction and humoral immune response of Epstein-Barr virus latent membrane protein 2 DNA vaccine

Jianqing PAN PhD, Qin ZHANG MD, Daowen WANG MD, PhD,

期刊论文

基于分布式表示语义组合的查询子主题挖掘

Wei SONG, Ying LIU, Li-zhen LIU, Han-shi WANG

期刊论文

Diagnostic criteria of latent autoimmune diabetes in adults (LADA): a review and reflection

Yu Liao, Yufei Xiang, Zhiguang Zhou

期刊论文

Probabilistic seismic response and uncertainty analysis of continuous bridges under near-fault ground

Hai-Bin MA, Wei-Dong ZHUO, Davide LAVORATO, Camillo NUTI, Gabriele FIORENTINO, Giuseppe Carlo MARANO, Rita GRECO, Bruno BRISEGHELLA

期刊论文