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Convergence of Monotone Iterations for Differential Problem

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Acta Mathematica Sinica,English Series 2000年第4期16卷 711-720页

作者： Tadeusz jankowski Department of Differential Equations. Technical University of Gdansk 11/12 G. Narutowicz Str. 80 952 Gdansk. Poland

We use the method of lower and upper solutions combined with monotone iterations to differential problems with a parameter. Existence of extremal solutions to such problems is proved.

关键词： Lower and upper solutions Monotone sequences Convergence Minimal and maximal solutions

Simulation of the response of base-isolated buildings under earthquake excitations considering soil flexibility

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Earthquake Engineering and Engineering Vibration 2012年第3期11卷 359-374页

作者： Sayed Mahmoud Per-Erik Austrell Robert jankowski Department of Construction Sciences Division of Structural MechanicsLund University Faculty of Engineering at Mataria Helwan University Faculty of Civil and Environmental Engineering Gdansk University of Technology

The accurate analysis of the seismic response of isolated structures requires incorporation of the flexibility of supporting soil. However, it is often customary to idealize the soil as rigid during the analysis of such structures. In this paper, seismic response time history analyses of base-isolated buildings modelled as linear single degree-of-freedom （SDOF） and multi degree-of-freedom （MDOF） systems with linear and nonlinear base models considering and ignoring the flexibility of supporting soil are conducted. The flexibility of supporting soil is modelled through a lumped parameter model consisting of swaying and rocking spring-dashpots. In the analysis, a large number of parametric studies for different earthquake excitations with three different peak ground acceleration （PGA） levels, different natural periods of the building models, and different shear wave velocities in the soil are considered. For the isolation system, laminated rubber bearings （LRBs） as well as high damping rubber bearings （HDRBs） are used. Responses of the isolated buildings with and without SSI are compared under different ground motions leading to the following conclusions：（1） soil flexibility may considerably influence the stiff superstructure response and may only slightly influence the response of the flexible structures; （2） the use of HDRBs for the isolation system induces higher structural peak responses with SSI compared to the system with LRBs; （3） although the peak response is affected by the incorporation of soil flexibility, it appears insensitive to the variation of shear wave velocity in the soil; （4） the response amplifications of the SDOF system become closer to unit with the increase in the natural period of the building, indicating an inverse relationship between SSI effects and natural periods for all the considered ground motions, base isolations and shear wave velocities; （5） the incorporation of SSI increases the number of significant cycles of large amplitude acce

关键词： base-isolated buildings rubber bearings earthquakes soil-structure interaction

Substructure isolation and damage identification using free responses

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Science China(Technological Sciences) 2014年第9期57卷 1698-1706页

作者： HOU JiLin jankowski Lukasz OU JinPing School of Civil Engineering Dalian University of Technology Smart-Tech Centre Institute of Fundamental Technological Research Polish Academy of Sciences School of Civil Engineering Harbin Institute of Technology

Structural health monitoring （SHM） has become a hot and intensively researched field in civil engineering. Thereinto, damage identification play an important role in maintaining structural integrity and safety. Many effective methods have been proposed for damage identification. However, accurate global identification of large real-world structures is not easy due to their com- plex and often unknown boundary conditions, nonlinear components, insensitivity of glohal response to localized damages, etc. Furthermore, global identification often requires lots of sensors and involves large number of unknowns. This is costly, rarely feasible in practice, and usually yields severely ill-conditioned identification problems. Substructuring approach is a possible solution： substructuring methods can focus on local small substructures; they need only a few sensors placed on the substruc- ture and yield smaller and numerically much more feasible identification problems. This paper proposed an improved sub- structure method using local free response for substructure damage identification. The virtual supports are constructed by Sub- structure Isolation Method （SIM） using the linear combination of the substructural responses. The influence of the global errors is isolated by adding the virtual supports on the main degree of freedoms （DOFs） of the substructure. Through the correlation analysis, the substructural modes are selected and used for damage identification of the substructure. A plain model of cable stayed bridge is used for the verification of the proposed method.

关键词： structural health monitoring (SHM) damage identification substructure cable stayed bridge free response

Improved source assessment of Si,Al and related mineral components to PM_(10) based on a daily sampling procedure

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Journal of Environmental Sciences 2010年第4期22卷 582-588页

作者： Ge Peng Hans Puxbaum Heidi Bauer Nicole jankowski Yao Shi Chemical Engineering College Ningbo University of Technology Ningbo 315016 China. Institute for Chemical Technologies and Analytics Vienna University of Technology Vienna 1060 Austria College of Environmental and Resource Sciences Zhejiang University Hangzhou 310027 China

Samples obtained from an industrialized valley in the East Alpine region were collected daily for a half year and analyzed using X-ray fluorescence to examine the elements Si, Al, Fe, Ca, Mg, Na, K, Zn, P, S and Cl. Some factors affecting the changes of these elements were considered, including time, elemental correlations, weekday, weekend and seasonal changes. Diagnostic analysis provided an insight into a decoupling behavior that occursin siliceous and carbonates minerals. A decrease in Si and Al and an increase in carbonates, Na, K, Zn and P were observed during the cold season. However, a consistently high correlation of Si and Al was observed in all seasons. It was established that such high levels originated from street surface abrasion. The increase in variability and absolute levels of carbonates during the cold season was demonstrated by adding carbonates to the street surface as gritting material to increase the grip on snowy surfaces. A marked increase in Na and Cl was observed in winter which may have been caused by thaw salt that is widely used in winter in Austria. This was associated with a significant increase in K, Zn, and P in the cold season that was the result of domestic space heating with wood. PM10 levels in December were 12 μ/m^3 and were higher than levels detected in July. It was established that such high levels originated from mineral oxides, wood smoke, and inorganic ionic material（s）.

关键词： particulate matter PM10 mineral aerosol silicates carbonates street dust wood combustion thaw salt

Reshaping the urban hierarchy:patterns of information diffusion on social media

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Geo-Spatial Information Science 2019年第3期22卷 149-165页

作者： Jiue-An Yang Ming-Hsiang Tsou Krzysztof Janowicz Keith C.Clarke Piotr jankowski Calit2/Qualcomm Institute University of California San DiegoLa JollaCAUSA Department of Geography San Diego State UniversitySan DiegoCAUSA Department of Geography University of CaliforniaSanta BarbaraCAUSA dInstitute of Geoecology and Geoinformation Adam Mickiewicz UniversityPoznańPoland

The spatial diffusion of information is a process governed by the flow of interpersonal *** emergence of the Internet and especially social media platforms has reshaped this process and previous research has studied how online social networks contribute to the diffusion of *** such processes can help devise methods to maximize or control the reach of information or even identify upcoming events and social *** activities in cyberspace are still confined to physical locations and this geographic connection tends to be *** this research,we focus on geographic regions instead of individuals and study how the underlying hierarchical structure of regions relates to their response to the *** examined the top 30 populated cities and metropolitan areas in the *** retrieved Twitter data related to two selected topics from these regions,the 2015 Nepal Earthquake and the#JesuisCharlie hashtag in response to the Paris attacks on the Charlie Hebdo *** analyzed the similarity among regions of their response using multiple statistical methods and three urban *** results indicate that the diffusion of information is impacted by the hierarchy of urban regions and that the Twitter responses act more similar when the populated regions are positioned at the same level in the urban hierarchy.

关键词： Information diffusion urban hierarchy spatiotemporal analysis social media

A framework for computer vision-based health monitoring of a truss structure subjected to unknown excitations

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 1-17页

作者： Mariusz Ostrowski Bartlomiej Blachowski Bartosz Wójcik Mateusz Żarski Piotr Tauzowski Łukasz jankowski Institute of Fundamental Technological Research Polish Academy of SciencesWarsawPoland Silesian University of Technology GliwicePoland Institute of Theoretical and Applied Informatics Polish Academy of SciencesGliwicePoland

Computer vision(CV)methods for measurement of structural vibration are less expensive,and their application is more straightforward than methods based on sensors that measure physical quantities at particular points of a ***,CV methods produce significantly more measurement ***,computer vision-based structural health monitoring(CVSHM)requires appropriate methods of damage assessment that are robust with respect to highly contaminated measurement *** this paper a complete CVSHM framework is proposed,and three damage assessment methods are *** first is the augmented inverse estimate(AIE),proposed by Peng et *** *** method is designed to work with highly contaminated measurement data,but it fails with a large noise provided by CV *** second method,as proposed in this paper,is based on the AIE,but it introduces a weighting matrix that enhances the conditioning of the *** third method,also proposed in this paper,introduces additional constraints in the optimization process;these constraints ensure that the stiffness of structural elements can only *** proposed methods perform better than the original *** latter of the two proposed methods gives the best results,and it is robust with respect to the selected coefficients,as required by the algorithm.

关键词： computer vision structural health monitoring physics-based graphical models augmented inverse estimate model updating non-negative least square method

The effect of the dietary inclusion of pea seeds of colored-flowered and white-flowered varieties on gastrointestinal function in turkeys

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Animal Nutrition 2022年第3期10卷 167-177页

作者： Zenon Zdunczyk Dariusz Mikulski Jan jankowski Bogdan A.Slominski Jerzy Juskiewicz Institute of Animal Reproduction and Food Research Polish Academy of SciencesOlsztyn 10-748Poland Department of Poultry Science and Apiculture University of Warmia and MazuryOlsztyn 10-718Poland Department of Animal Science University of ManitobaWinnipeg R3T 2N2Canada

This study investigated the effects of dietary replacement of soybean meal(SBM)with graded levels of pea seeds(PS)on the gastrointestinal function of *** of 2 pea varieties,a colored-flowered variety and a white-flowered variety(CFP and WFP,respectively)were fed to 56-d-old birds for 8 wk.A total of 539 female Hybrid turkeys were allocated to 7 groups,each group consisted of 7 pens with 11 birds per *** experiment had a 2-factorial design,with 3 dietary inclusion levels of PS(100,200 and 300 g/kg)and 2 pea varieties(CFP and WFP).The control group(diets without PS)was compared with CFP and WFP treatments by simple contrast *** comparison with CFP seeds,WFP seeds contained 7-fold less tannins(0.67 vs.4.66 g/kg)and less non-starch polysaccharides(NSP,117.8 vs.132.7 g/kg),but more trypsin inhibitors(1.34 vs.0.98 g/kg)and starch(489 vs.455 g/kg).A rise in the PS content of diets from 100 to 200 and 300 g/kg increased the weight of the small intestine(P=0.031)and the dry matter(DM)content of intestinal digesta(P=0.001),but it had no effect on the pH of *** the highest PS content differentiated the concentrations of short-chain fatty acids(SCFAs)in the small intestinal digesta(WFP>CFP,P=0.008),whereas PS did not cause any changes in the morphological parameters of the small intestinal *** dietary inclusion of PS had no influence on the levels of acetate,butyrate,putrefactive SCFAs or total SCFAs in the cecal *** from increasing the activities of b-glucosidase(P=0.017)and b-galactosidase(P=0.025),pea varieties did not affect the activities of the analyzed cecal microbial ***,CFP seeds decreased the DM content(P=0.041)and increased the pH of cecal digesta,compared with WFP seeds(P=0.013).The results of this study,pointing to a few differences in the functional parameters of the small intestine and cecum,indicate that tannins are not a factor differentiating the suitability of CFP and WFP seeds in the nutrition of f

关键词： Pea Tannin Growth performance Gastrointestinal tract Turkey

联合整体和局部动态信息的空间桁架模型修正试验

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振动与冲击 2013年第16期32卷 100-105页

作者：侯吉林欧进萍 Lukasz jankowski 大连理工大学土木工程学院大连116024 哈尔滨工业大学土木工程学院哈尔滨150090 波兰科学院基础技术研究所智能技术部

由于土木工程结构的复杂性、传感器测点的有限性以及局部损伤的不敏感性等问题,大型结构的模型修正存在一定困难。针对空间桁架结构,为克服上述问题,对其进行整体和局部的动力测试试验,然后联合实测的结构整体和局部动态信息进行模型修... 详细信息

由于土木工程结构的复杂性、传感器测点的有限性以及局部损伤的不敏感性等问题,大型结构的模型修正存在一定困难。针对空间桁架结构,为克服上述问题,对其进行整体和局部的动力测试试验,然后联合实测的结构整体和局部动态信息进行模型修正:首先进行空间桁架整体的动力测试试验,获得反应整体特性的低阶模态;然后为了提高局部杆件的动态特性,在杆件上附加一定质量,获得附加质量后杆件的局部主频率,并在各类杆件中选取一定数目进行动态测试;最后联合所有实测结构整体的低阶模态和杆件的局部主频率,对空间桁架结构进行模型修正。修正后的模态参数与实测模态吻合良好,验证了方法的有效性。

关键词：结构健康监测模型修正桁架频率振型

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约束子结构损伤识别的时序方法研究与试验

工程力学 2013年第4期30卷 129-135页

作者：侯吉林欧进萍 Lukasz jankowski 大连理工大学土木工程学院大连116024 哈尔滨工业大学土木工程学院哈尔滨150090 波兰科学院基础技术研究所智能技术部

针对大型复杂结构的整体监测常常面临测量信息不足等困难,提出只利用局部动态响应进行子结构损伤识别的约束子结构方法。约束子结构方法是通过子结构响应的卷积组合限制子结构边界的响应为零,来实现施加虚拟支座,从而将子结构分离出整体... 详细信息

针对大型复杂结构的整体监测常常面临测量信息不足等困难,提出只利用局部动态响应进行子结构损伤识别的约束子结构方法。约束子结构方法是通过子结构响应的卷积组合限制子结构边界的响应为零,来实现施加虚拟支座,从而将子结构分离出整体,然后利用构造的相应子结构内部响应,进行子结构损伤识别。该文利用先分段提取结构响应的子时间序列,再延时排列Toeplitz矩阵的方式,使基于不同响应的构造约束子结构的方程具有相同表达式,统一了约束子结构方法的基本思想。通过测量悬臂梁的局部动力响应,利用局部响应的时间序列实现了子结构的快速准确地分离和识别,验证了方法的实用性和有效性。

关键词：结构健康监测损伤识别子结构时间序列脉冲响应