New Method For Modeling Research Articles

A new method for modelling and simulation of the dynamic behaviour of the wheel-rail contact

This paper presents a new method for modelling and simulation of the dynamic behaviour of the wheel-rail contact. The proposed dynamic wheel-rail contact model comprises wheel-rail contact geometry, normal contact problem, tangential contact problem and wheelset dynamic behaviour on the track. This two-degree of freedom model takes into account the lateral displacement of the wheelset and the yaw angle. Single wheel tread rail contact is considered for all simulations and Kalker's linear theory and heuristic non-linear creep models are employed. The second order differential equations are reduced to first order and the forward velocity of the wheelset is increased until the wheelset critical velocity is reached. This approach does not require solving mathematical equations in order to estimate the critical velocity of the dynamic wheel-rail contact model. The mathematical model is implemented in Matlab using numerical differentiation method. The simulated results compare well with the estimated results based on classical theory related to the dynamic behaviour of rail-wheel contact so the model is validated.

Improved Noise Modeling with Mutual Coupling in Receiving Antenna Arrays for Direction-of-Arrival Estimation

A new method for modeling correlated noise in receiving antenna arrays for direction-of-arrival (DOA) estimation is introduced. The array noise is divided into a coupled and an uncoupled components which originate from the array environment and the internal circuitry of the antenna elements, respectively. While the uncoupled noise power can be determined a priori and be removed from the array received power, the antenna mutual coupling in the coupled noise component can be decoupled in the same way as the antenna mutual coupling in the signals. This results in a very simple but effective MUSIC DOA estimation algorithm. Simulation results are presented to validate and demonstrate the performance of the new method.

Analysis of integral non-linearity errors in two-step analogue-to-digital converters

A new method for modelling and analysis of non-linearity errors caused by the capacitor mismatches and op-amp non-idealities in two-step analogue-to-digital converters (ADCs) is presented. Analytical formulas for estimation of the ADC integral non-linearity (INL) are derived. Using the proposed method, the ADC INL can be calculated in terms of the capacitor mismatches standard deviations. Therefore time-consuming Monte Carlo simulations which are conventionally used to evaluate the effect of random capacitor mismatches on the ADC linearity can be avoided. The effect of op-amp non-idealities, which are frequently examined by the circuit-level simulations, can also be evaluated using the derived model for the INL in terms of the op-amp DC gain and non-linearity. Accuracy of the proposed model is validated by the system and circuit-level Monte Carlo simulations. By using the proposed model, static performance of the conventional restoring (CR) and redundant signed digit (RSD) converters in the presence of mentioned errors are compared.

Grey New Information GRM(1,1) Model Based on Accumulated Generating Operation of Reciprocal Number and its Application

Monotonically decreasing sequence data for the traditional modeling method using the gray model accuracy is not high, using Accumulated Generating Operation in reciprocal number, utilize three gray derivative processing method is deduced and the parameters optimization grey derivative calculation formula, and then established GRM(1,1) based on accumulated generating operation in reciprocal number on the equidistance, Gray provides a new method of modeling. Data processing examples show that the model's practicality and reliability.

Grey New Information Unbiased GRM(1,1) Model Based on Accumulated Generating Operation in Reciprocal Number and its Application

Monotonically decreasing sequence data for the traditional modeling method using the gray model accuracy is not high , and GM (1, 1) modeling method has inherent deviation , Model does not meet the compatibility condition, using Accumulated Generating Operation in reciprocal number ,make best use of last information and GM (1, 1) modeling , is deduced and the parameters optimization grey derivative calculation formula ,and then established GRM(1,1) based on accumulated generating operation in reciprocal number on the equidistance, Gray provides a new method of modeling . Data processing examples show that the model's practicality and reliability.

A New Method for Modeling of Fully Flexible Aircrafts

The purpose of this study is to produce a modeling capability for integrated flight dynamics of flexible aircraft that can better predict some of the complex behaviors in flight due to multi-physics coupling. Based on the studying of the exiting modeling approaches, the author put forward a new modeling method, and developed a new formulation integrating nonlinear rigid-body flight mechanics and linear aeroelastic dynamics for fully elastic aircrafts using Lagrangian mechanics. The new equations of motion overcome the disadvantages of the exiting methods, and include automatically all six rigid-body degrees of freedom and elastic information, the seamless integration is achieved by using the same reference frame and the same variables to describe the aircraft motions and the forces acting on it, including the aerodynamic forces. The formulation is modular in nature, in the sense that the structural model, the aerodynamic theory, and the controls method can be replaced by any other ones to better suit different types of aircraft.

A new model for deformed carbon nanotubes using Green’s function

A new method for modeling and analysis of deformed carbon nanotubes (CNTs) using Green’s function, is presented in this paper, for the first time. Using the proposed method, a new circuit model is obtained for the deformation region of a deformed single-walled CNT (SWCNT), which the values of its elements depend on the type of deformation and also the deformation parameters such as the coupling matrices and the energy variations of deformation region. The comparison between the obtained results from the analysis of proposed model and the literature gives a good match which approves the accuracy and correctness of the proposed model.

Modeling of time-variant heterogeneous objects in micro-system packages

UBM (under bump metallurgy) of micro-system packages consists of several heterogeneous layers such as solder wetting, diffusion barrier, adhesion, and IMC (inter-metallic compound) layers. In particular, the IMC layer, formed between the solder wetting layer (e.g., Cu or Ni) and the solder, grows gradually and thus its composition changes with time (i.e., time-variant). The primary failure mechanism of the solder joints in micro-system packages is widely known as the fatigue failure caused by thermal fatigue and electro-migration damage. However, these phenomena have thus far been viewed from experimental investigations. Therefore, finite element analysis (FEA) becomes an important step for the optimal design and reliability analysis of heterogeneous objects such as in micro-system packages. However, the accuracy of the FEA wholly depends on the quality of finite element models. There thus exists an increasing need for generating finite element models adaptive to both geometric complexity and material distribution. In this sense, this paper presents a new method for modeling of time-variant heterogeneous objects such as in micro-system packages whose composition changes with time. Heterogeneous Boolean operators based on the diffusion process are proposed to construct time-variant heterogeneous objects. Once a time-variant heterogeneous solid model is constructed, it is then discretized into an object model onto which appropriate material properties are mapped. Discretization converts continuous material variations inside an object into stepwise variations. Next, the object model is adaptively meshed and converted into a finite element model. FEA using commercial software is finally performed to check failure criteria. An example (UBM in micro-system package) is shown to illustrate the entire modeling procedure.

Architectural evaluation of simulated pedestrian spatial behaviour

The purpose of the software system described in this article is to support architects and urban designers to better assess the impact of pedestrian behaviour on planned urban spaces and streetscapes. A new method for modelling and simulating pedestrians in urban environments is proposed. It analyses pedestrian behaviour with a combined focus on movement trajectories, walking speed and the angle between the movement vector and the gaze vector of individuals in large groups of simulated pedestrians. The system learns a statistical model characterizing normal behaviour, based on sample observations of regular pedestrian movements without the impact of significant visual attractions in the environment. Sudden changes of the pedestrians' behavioural characteristics, caused by the visual detection of ‘attractive’ objects, are considered as abnormal behaviour. The simulated environment can be automatically generated using scanned line drawings of two-dimensional street maps or public spaces. In the simulation model, a variety of scenarios can be defined and modified by altering different parameters. Using the example of Wheeler Place in Newcastle (Australia), our pilot experiments demonstrate how pedestrian behaviour characteristics can depend on selected abstract features in urban space. Among 10 different example scenarios, the analyser was able to identify the most frequently visited positions associated with attractive objects.

Simulation of the Control System of Step Motor Based on LabVIEW

Based on the mathematical model of the step motor, a new method for modeling and simulation of step motor based on LabVIEW is proposed. The reasonability and validity are testified by the coincidence of the simulation and experimentation results and theory analysis. This method offers a new thinking for designing and debugging actual motors.

Far-end Crosstalk Modeling Based on Capacitive and Inductive Unbalances Between Pairs in a Cable

This article deals with new ways of far-end crosstalk (FEXT) modeling in multi-pair and multi-quad metallic cables. Current standard modeling methods provide only rough estimations of FEXT characteristics based on average values of crosstalk for the whole cable. However, for practical implementation of vector discrete multi-tone modulation (VDMT) is necessary to predict and simulate FEXT characteristics with sufficient accuracy and simulate FEXT transfer functions individually for each combination of symmetrical pairs in a cable. This article contains a theoretical analysis and description of the problem and suggests a new method for modeling of FEXT crosstalk using capacitive and inductive unbalances between pairs in a cable. This proposed model offers more accurate and realistic results of crosstalk. Theoretical simulations and results are also compared with the measured characteristics for specific metallic cable.

Model for spatial-correlated clutter and its application to temporal–spatial correlated clutter

Time-correlated clutter simulation based on the zero memory non-linearity transformation (ZMNL) and spherically invariant process (SIRP) suffers from spectrum expansion, and spatial-correlated clutter simulations may suffer from calculation complexity. To overcome these drawbacks, a new method of modelling and simulation of temporal–spatial-correlated clutter is proposed, based on the weighted norm in discrete complex linear space and a simple matrix transformation. Time-correlated clutter sequences with exact spectra can be generated by this algorithm through solving the minimum discrete weighted norm; whereas the spatial-correlated clutter can be generated by simple linear matrix transformations without complex calculations. It is shown that temporal–spatial-correlated clutter can be exactly and simply generated by the proposed method. Numerical simulation results show the feasibility and accuracy of this method.

A method for modelling of parameter estimation laws depending on functions for adaptive control of robot manipulators

In this paper, first, a new method for modelling of adaptive control laws for controlling robot manipulators is presented. Then, based on the Lyapunov theory, we have proposed five new adaptive control laws thus, stability of uncertain system is guaranteed. Based on previous studies, adaptive control laws are derived from Lyapunov theory using some different functions depending on tracking error, robot inertia and kinematics parameters. This study also shows not only that adaptive controllers cover these derivations but also that it would be possible to derive another parameter adaptive law based on this study providing that appropriate function is chosen. Application to a two-link robotic manipulator is presented. Numerical simulation results are included.

Modelling of business services in service oriented enterprises

Abstract The idea of on demand business combines information technology and business to make the companies more rapid, responsible and profitable. Today, the most important thing that can be considered for an enterprise is flexibility, which, in this context, means having more flexibility in responding to new demands of the market and grasping the opportunities. In order to increase its flexibility, first of all, business enterprise takes a look at its interrelated activities and then specifies which activity is distinct and axial and which can be outsourced. If the companies can combine and coordinate these activities as they desire, then they will enjoy remarkable excellence in market. Extraordinary alignment between information technology and business is a result of Service Oriented Architecture (SOA) approach, which has made the organizations have a special look at this approach for execution of software projects. Business processes are used for modeling internal and external operations of the organizations for several decades and accidentally such a modeling has rapidly become a standard modeling in businesses, companies and enterprises, booming outsourcing market and making the enterprises and companies grow by such modeling and benefit from remarkable savings. But, there is a serious need for new methods for modeling enterprises operations in order to identify and use the common features between companies and enterprises for decrease the costs and enjoy more savings. In this paper, an approach is introduced that is based on business services for service orientation of enterprises. Molding the business services is one of the innovative methods for achieving the objectives concerned in the business.

The Effect on Learning, Communication, and Assessment When Student-Created Youtubes of Microteaching Were Used in an Online Teacher-Education Course

This pilot study within an online teacher-education course required pre-service teachers to develop self-videotaped microteaching lessons which were posted in a private YouTube. Analysis of the students' YouTube lessons, course postings, and peer interactions found that students learned the technology requirements quickly, were able to develop useful collegial relationships, and were adept at developing science lessons that integrated data-probe and spreadsheet technology. The YouTube lessons, though, illustrated how these pre-service teachers still struggled with creating student-centered lessons. The utility of a performance assessment that can be taped, stored, and analyzed reinforces the value of this approach; YouTube-like postings could help fields with service and performance components (social work, nursing). New methods for modeling, supporting and assessing students in such areas will be needed. However, the value of instruction that is better aligned with the desired outcome argues the value of investing in supporting, integrating, and designing assessments for these rapidly-expanding technology-and-communications tools.

Formalization of semantics of systems with unreliable agents by means of nets of active resources

A new method for modeling distributed systems--nets of active resources--is presented. The expressive power of this formalism is similar to that of ordinary Petri nets, but its syntax relies on a different modeling principle: instead of partitioning model components (nodes of the graph) into agents and resources (transitions and places), partitioning of the ways of interaction (arcs of the graph) in terms of production and consumption is introduced. Direction of an arc determines whether the interaction is active or passive: one and the same component upon different firings may play role of both an agent and a resource. In nets of active resources and their syntactic extensions, there appears an opportunity for convenient formalization of various semantic properties, such as simultaneous work of agents, agent blocking, redundancy of the number of agents, a possibility of replacement of an unreliable node by a reliable one, and the like. A method for constructing distributed applications based on dynamically configured sets of executable modules is considered. It is shown that the use of nets of active resources allows one to specify their structure, as well as to formulate properties of such systems, in a natural way.

Production of biofuels and biochemicals: in need of an ORACLE

The engineering of cells for the production of fuels and chemicals involves simultaneous optimization of multiple objectives, such as specific productivity, extended substrate range and improved tolerance - all under a great degree of uncertainty. The achievement of these objectives under physiological and process constraints will be impossible without the use of mathematical modeling. However, the limited information and the uncertainty in the available information require new methods for modeling and simulation that will characterize the uncertainty and will quantify, in a statistical sense, the expectations of success of alternative metabolic engineering strategies. We discuss these considerations toward developing a framework for the Optimization and Risk Analysis of Complex Living Entities (ORACLE) - a computational method that integrates available information into a mathematical structure to calculate control coefficients.

A New Method for Modeling of Initiation and Propagation of Delamination Between [0/θo] Layers of Laminated Composites

In this article, initiation and propagation of delamination of a double cantilevered beam (DCB) is studied. The delamination of DCB specimen occurs between 0 o and θ 0 layers. Due to damage induced, during the loading, in the matrix of θ 0 layer, virtual crack closure technique (VCCT) as a well known method for simulation of initiation and propagation of the delamination for DCB is not able to model the propagation of delamination properly. To overcome this shortcoming, the stiffness of the damaged θ 0 layer is decreased with a developed technique in this study. The stiffness reduction technique (SR) is introduced in this paper to model the induced cracks in the matrix of the θ 0 layer. Then the stiffness reduction technique is coupled with the critical length parameter. The presented method is called stiffness reduction—critical length (SR-CL) method. By using SR-CL method, initiation and propagation of delamination for a $$ \left[ {{{\left( {0_2^o/{{90}^o}} \right)}_6}/0_2^o//{\theta^o}/{{\left( {0_2^o/{{90}^o}} \right)}_6}/0_2^o} \right] $$ configuration in which θ = 0o, 22.5o, 45o, 67.5o, 90o and for a cross ply laminate (0°/90°) 12 are modeled. The obtained results are in very good agreements with experimental data.

Turbojet Engines - Progressive Methods of Modeling

Small turbojet engines represent a special class of turbine driven engines. They are suitable for scientific purposes and research of certain thermodynamic processes ongoing in turbojet engines. Moreover such engines can be used for research in the area of alternative fuels and new methods of digital control and measurement. Our research, which is also presented in this article, is headed toward these aims. We evaluate and propose a system of digital measurement of a particular small turbojet engine - MPM 20. Such engine can be considered as highly non-linear large scale system. According to obtained data and experiments we propose different approaches to modeling of the engine with use of analytic experimental and certain methods of artificial intelligence as new methods of modeling of complex systems.

Furstyling on angle-split shell textures

This paper presents a new method for modeling and rendering fur with a wide variety of furstyles. We simulate virtual fur using shell texturesa multiple layers of textured slices for its generality...