检索结果-内蒙古大学图书馆

arXiv 2017年

作者： Greco, A. Pluchino, A. Barbarossa, L. Caliò, I. Martinico, F. Rapisarda, A. Department of Civil Engineering and Architecture University of Catania viale A. Doria 6 Catania Department of Physics and Astronomy University of Catania Infn Sezione di Catania via S.Sofia 64 Catania Complexity Science Hub Vienna

The analysis of the seismic vulnerability of urban centres has received a great attention in the last century, due to the progressive concentration of buildings in metropolitan areas. In order to estimate the seismic vulnerability of a densely populated urban area, it would in principle be necessary to develop in-depth analyses for predicting the dynamic behaviour of the individual buildings and their structural aggregation. Such analyses, however, are extremely cost-intensive, require great processing time and above all expertise judgement. It is therefore very useful to define simplified rules for estimating the seismic vulnerability of whole urban areas by simulating different types and intensities of seismic stresses. In the last decades, the Self-Organized Criticality (SOC) scenario has gained increasing credibility as a mathematical framework for explaining a large number of naturally occurring extreme events, from avalanches to earthquakes dynamics, from bubbles and crises in financial markets to the extinction of species in the evolution or the behaviour of human brain activity. All these examples show the intrinsic tendency common to many phenomena to spontaneously organize into a dynamical critical state, whose signature is the presence of a power law behaviour in the frequency distribution of events. In this context, the Olami-Feder-Christensen (OFC) model, introduced in 1992, has played a key role in modelling earthquakes phenomenology. The aim of the present paper is proposing an agent-based model of earthquake dynamics, based on the OFC self-organized criticality framework, in order to evaluate the effects of a critical sequence of seismic events on a given large urban area during a given interval of time. The further integration of a GIS database within a software environment for agent-based simulations, will allow to perform a preliminary parametric study of these effects on real datasets. The model could be useful for defining planning strategies fo

关键词： Computational methods

来源：评论

学校读者我要写书评

暂无评论

Measurement of digital photographic image quality: Survey of psychophysics just noticeable threshold difference method 6

Measurement of digital photographic image quality: Survey of...

引用

6th IASTED International conference on modelling and Simulation, AfricaMS 2016

作者： Lindeque, Pierre Nel, Andre Robinson, Philip Department of Electrical and Computer Engineering Technology South Africa Department of Mechanical Engineering Science University of Johannesburg South Africa

ISBN: (纸本)9780889869844

The modeling and quantification of digital photographic image quality has, from a psychophysics perspective, traditionally followed two paths, one of which is the discriminable small or just noticeable difference (local psychophysics) as detected in an image pair;further extended to cover a wide range of attribute artefactual quality variation. This method has its roots in the mathematical and psychological modeling of psychophysics and boasts a long history starting with the work of researchers such as Bernoulli, Weber and Fechner (18th, 19th century). The method models human perception of difference as a full scale logarithmic law and will be surveyed for its value in the determination of the quantitative quality of digital images.

关键词： Image quality

来源：评论

学校读者我要写书评

暂无评论

modelling creep behaviour of blue gum 35

Modelling creep behaviour of blue gum

引用

35th IASTED International conference on modelling, Identification and Control, MIC 2016

作者： Carvalho, Sofia Lopes, Duarte Barroso Portugal Assistant at ISEP School of Engineering of Porto DEC Department of Civil Engineering Rua Dr. António Bernardino de Almeida n. 431 Porto4200-072 Portugal

ISBN: (纸本)9780889869790

Blue gum is a viscoelastic material strongly influenced when under constant load (Creep), being this phenomenon-in the context of displacements-exacerbated with transient relative humidity (variations the water content in the material). The evaluation of mechano-sorptive effect in bending for 60 days long with cycles of wetting / drying (with 7 days-1 week of duration-1 cycle) according EN 1156 was done. Samples of Eucalyptus globulus Labill. wood species with dimensions of 20 20 400 mm was used (app. scale 1:10 RxTxL mm3, respectively). To fit the creep behavior and extrapolate results for different periods (1, 10 and 50 years) a survey of different numerical models was done. In the tests, Blue gum wood specie presented a behavior in bending without a creep limit, therefore labile. A significant variability in different extrapolations (through models used) was found, exceeding the recommended values obtained through the rules of the main standard of wood design (Eurocode 5). Out of the six theoretical mathematical models used, one that has led to closer results, therefore more appropriate, was the parabolic model.

关键词： Creep

来源：评论

学校读者我要写书评

暂无评论

modelling moisture sorption isotherms for Orthosiphon stamineus spray-dried powder

引用

AIP conference Proceedings 2018年第1期2030卷

作者： N. A. Razak I. A. Jazlan A. R. Shaari L. Y. Leng 1Faculty of Engineering Technology Universiti Malaysia Perlis (UniMAP) Campus of UniCITI Alam Sungai Chuchuh Padang Besar 02100 Perlis Malaysia

The Orthosiphon stamineus spray-dried powder have many benefits for human consumption either as supplement or natural herbal medicinal. It can cure many diseases especially urinary tract, diabetic and kidney stones. The moisture sorption isotherm is very important to identify the desirable storage condition and the shelf life of O. stamineus spray-dried powder. Moisture sorption isotherm of O. stamineus extract powder were determined through the gravimetric method at two selected temperature which were 4 and 30 °C. Five type of different saturated salts such as lithium chloride, magnesium chloride, potassium carbonate, sodium bromide and potassium nitrate were used in this study. The setup range of relative humidity were 11 to 95%. There were two type of mathematical modelling used to validate the data that have been taken from the research work which are GAB and BET model. Based on the results, it was found that the GAB model shows the best fit model as all the data from this research have the nearest value of the GAB fitting criteria. This is due to the value of coefficient of correlation, R2 = 0.998 at 30 °C in adsorption process.

关键词：

来源：评论

学校读者我要写书评

暂无评论

mathematical modelling OF THE REAR DRIVE UNIT OF A LIGHTWEIGHT VEHICLE FOR SENSITIVITY ANALYSIS OF VIBRATION

MATHEMATICAL MODELLING OF THE REAR DRIVE UNIT OF A LIGHTWEIG...

引用

ASME International Design engineering Technical conferences and Computers and Information in engineering conference (IDETC/CIE)

作者： Lin, Jiewei Qiu, Yi Univ Southampton Inst Sound & Vibrat Res Southampton Hants England

ISBN: (纸本)9780791850138

Lightweight technology is applied in the automobile industry because mass reduction is beneficial in improving fuel efficiency and reducing CO2 emissions. Apart from the car body and the power unit (the two heaviest parts of a vehicle), the driveline also has potential for a reduction in weight. The driveline transfers power to the wheels and plays an important role in the vehicle system. Vibration is induced by the road input and by unbalanced forces transmitted through the driveline to the car body. Mass reduction in the driveline could influence the dynamic behaviour of a vehicle but it is not yet clear how mass reduction affects vibration of the driveline, the vehicle ride and NVH performance important considerations when designing a lightweight driveline. In the prototype design stage, a mathematical model provides a more flexible and less costly method of optimising the system dynamics. In this paper, a 14 degree-of-freedom mathematical model is developed to study the dynamics of a rear drive unit (RDU). The system consists of a rear differential gearbox, left and right constant velocity joints and driveshafts, a. rear sub-frame, and bushings between the RDU and the sub-frame and between the sub-frame and the car body. Excitations from the rear wheels, rear suspensions, and input shaft were considered. The vertical acceleration at the rear sub-frame was calculated and correlated with a calibrated multi-body dynamic model of the vehicle developed in a parallel study. Using a fractional factorial design with the vehicle travelling on a smooth road at various speeds, a sensitivity analysis was carried out with the developed mathematical model to identify the contributions of the mass properties of the RDU and the bushing parameters to the vibration at the centre of gravity (COG) of the rear sub-frame. Results indicate that the effects of design parameters on the rear sub-frame vibration vary according to the vehicle speed. For vibration at the rear sub-frame, the

关键词： Bushings Center of mass Emissions Sensitivity analysis Stiffness Dynamics (Mechanics) Vibration Carbon dioxide Design Mechanical drives Roads System dynamics Vehicles Excitation Modeling engineering prototypes Automotive industry Weight (Mass) Dynamic models Degrees of freedom Wheels Fuel efficiency

来源：评论

学校读者我要写书评

暂无评论

The development of an ontology for driving context modelling and reasoning 19

The development of an ontology for driving context modelling...

引用

19th IEEE International conference on Intelligent Transportation Systems, ITSC 2016

作者： Xiong, Zhitao Dixit, Vinayak V. Travis Waller, S. School of Civil and Environmental Engineering UNSW Australia

ISBN: (纸本)9781509018895

In order to use technology to influence human behaviour and promote safer and more fuel efficient behaviour through incentive mechanisms, an instrumented vehicle is developed. The first step is to make it "perceive" the outside world, so extracting knowledge from some data sources such as sensors is crucial. More critically, there is a fundamental need for a standard that would enable knowledge sharing/exchanging among the different entities, e.g., between on-board sensors, invehicle controls and traffic management agencies. This paper proposes an Ontology for Context modelling (OCM) to be used as the world model for driving context representation and reasoning, which can enable a better understanding of traffic context and sensor capability, which is the basis for providing data source to Advanced Driver Assistance Systems (ADAS), V2X (Vehicle-To-Everything) communications and even driving decision making within autonomous vehicles. Through the experiments, we evaluate the capability of the OCM to represent the driving context and the reasoning mechanism to compensate for sensor failures and recognize lane changing and overtaking events. This methodology has significant value for creating standards in autonomous and semi-Autonomous cars. © 2016 IEEE.

关键词： Ontology

来源：评论

学校读者我要写书评

暂无评论

Review on Thermo-mechanical Approach in the modelling of Geo-materials Incorporating Non-Associated Flow Rules

Review on Thermo-mechanical Approach in the Modelling of Geo...

引用

3rd International conference on Transportation Geotechnics (ICTG)

作者： Aung, Ye Khabbaz, Hadi Fatahi, Behzad Univ Technol Sydney Sch Civil & Environm Engn Sydney NSW Australia Univ Technol Sydney Sch Civil & Environm Engn Geotech Engn Sydney NSW Australia

Recently, there has been a burgeoning interest in developing constitutive soil models from the laws of thermodynamics, mainly due to the benefits that these models automatically obey them and the approach provides a well-established structure and reduces the need for 'ad hoc' postulates. A thermodynamic framework, also known as thermo-mechanical framework, has the capability to predict the behaviour of geotechnical materials, which requires the anticipated incorporation of non-associated flow rules. As it is very challenging to achieve acceptable accuracy in plasticity modelling of granular materials, this paper aims to review this framework not only to discuss the details of the major components but also to highlight the capability of generating non-associated flow rules in a natural way from thermo-mechanical principles. This approach introduces the use of internal variables to develop the two thermodynamic potentials (the free energy and the rate of dissipation functions), sufficient to derive the corresponding yield function, flow rule, isotropic and kinematic hardening rules as well as the basic elasticity law. It is shown that the non-associated flow rule can be derived naturally from the postulated stress-dependent dissipation increment function. Comparison has been made with stress-independent dissipation to demonstrate that the approach can also successfully explain the behaviour of standard materials with associated flow rules. The basic steps for the thermomechanical formulation for developing a constitutive model are also reviewed and summarised. Furthermore, the power of conventional mathematical technique, Legendre transformation, in the derivation of constitutive equations has been highlighted.

关键词： thermo-mechanical free energy dissipation frozen elastic energy geo-materials granular

来源：评论

学校读者我要写书评

暂无评论

13th International conference on Dynamical Systems, 2015

13th International Conference on Dynamical Systems, 2015

引用

13th International conference on Dynamical Systems, 2015

ISBN: (纸本)9783319424019

The proceedings contain 35 papers. The special focus in this conference is on Systems and modelling. The topics include: On dynamic behavior of a nonideal torsional machine suspension structure;analysis of the dynamic behavior of a radar tower;modelling of forward fall on outstretched hands as a system with ground contact;the sensitivity analysis of the method for identification of bearing dynamic coefficients;investigations of composite panels mounted in the cargo space of a freight wagon;analysis of dynamical response of the freight wagon;evolutionary model for synthetic spectrum compatible accelerograms;a parametric study of mixing in a granular flow a biaxial spherical tumbler;a mathematical model for robot-indenter;nonlinear dynamics of a vibration harvest-absorber system experimental study;the method of modeling of human skeletons multi-body system;analytical model of dynamic behaviour of fatigue test stand-description and experimental validation;assessment of modal parameters of a building structure model;modeling of buildings behavior under blast load;hydraulically driven unit converting rotational motion into linear one;optimization of micro-jet selective cooling after low alloy steel welding;modelling of thermoelectric processes in FEM environment based on experimental studies;numerical model of femur part and FEA-based design of experiment for the damping determination of thermoplastic-rubber compounds.

关键词：

来源：评论

学校读者我要写书评

暂无评论

mathematical solution of the stone column effect on the load bearing capacity and settlement using numerical analysis

引用

Journal of Physics: conference Series 2018年第1期995卷

作者： A Madun S A Meghzili SAA Tajudin M F Yusof M H Zainalabidin A A Al-Gheethi M F Md Dan M A M Ismail Faculty of Civil and Environmental Engineering Universiti Tun Hussein Onn Malaysia (UTHM) 86400 Parit Raja Batu Pahat Johor Malaysia Micro-pollution Research Centre (MPRC) Department of Water and Environmental Engineering Faculty of Civil and Environmental Engineering Universiti Tun Hussein Onn Malaysia (UTHM) 86400 Parit Raja Batu Pahat Johor Malaysia School of Civil Engineering University Sains Malaysia Malaysia

The most important application of various geotechnical construction techniques is for ground improvement. Many soil improvement project had been developed due to the ongoing increase in urban and industrial growth and the need for greater access to lands. Stone columns are one of the best effective and feasible techniques for soft clay soil improvement. Stone columns increase the bearing capacity and reduce the settlement of soil. Finite element analyses were performed using the program PLAXIS 2D. An elastic-perfectly plastic constitutive relation, based on the Mohr–Coulomb criterion, governs the soft clay and stone column behaviour. This paper presents on how the response surface methodology (RSM) software is used to optimize the effect of the diameters and lengths of column on the load bearing capacity and settlement of soft clay. Load tests through the numerical modelling using Plaxis 2D were carried out on the loading plate at 66 mm. Stone column load bearing capacity increases with the increasing diameter of the column and settlement decreases with the increasing length of the column. Results revealed that the bigger column diameter, the higher load bearing capacity of soil while the longer column length, the lower settlement of soil. However, the optimum design of stone column was varied with each factor (diameter and length) separately for improvement.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Quantitative groundwater modelling for a sustainable water resource exploitation in a Mediterranean alluvial aquifer

引用

AIP conference Proceedings 2018年第1期1968卷

作者： Mounir Laïssaoui Mohamed Mesbah Khodir Madani Hocine Kiniouar 1Biophysics Biomathematics and Scientometry Laboratory Department of Biological Sciences of the Environment Abderrahmane Mira University of Bejaia. Targa-Ouzemour Road Bejaia 06000 Algeria 2Departement of Geology University Of Sciences and Technology Houari Boumediene. BP 32 El Alia Bab Ezzouar Alger Algeria 3Geological Engineering Laboratory Mohamed Seddik Benyahia University of Jijel PB 98 Ouled Aissa Jijel 18000 Algeria

To analyze the water budget under human influences in the Isser wadi alluvial aquifer in the northeast of Algeria, we built a mathematical model which can be used for better managing groundwater exploitation. A modular three-dimensional finite-difference groundwater flow model (MODFLOW) was used. The modelling system is largely based on physical laws and employs a numerical method of the finite difference to simulate water movement and fluxes in a horizontally discretized field. After calibration in steady-state, the model could reproduce the initial heads with a rather good precision. It enabled us to quantify the aquifer water balance terms and to obtain a conductivity zones distribution. The model also highlighted the relevant role of the Isser wadi which constitutes a drain of great importance for the aquifer, ensuring alone almost all outflows. The scenarios suggested in transient simulations showed that an increase in the pumping would only increase the lowering of the groundwater levels and disrupting natural balance of aquifer. However, it is clear that this situation depends primarily on the position of pumping wells in the plain as well as on the extracted volumes of water. As proven by the promising results of model, this physically based and distributed-parameter model is a valuable contribution to the ever-advancing technology of hydrological modelling and water resources assessment.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：