for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> ENGINEERING (Total: 2017 journals)
    - CHEMICAL ENGINEERING (159 journals)
    - CIVIL ENGINEERING (153 journals)
    - ELECTRICAL ENGINEERING (86 journals)
    - ENGINEERING (1135 journals)
    - ENGINEERING MECHANICS AND MATERIALS (308 journals)
    - HYDRAULIC ENGINEERING (48 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (76 journals)

ENGINEERING (1135 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Lifecycle Performance Engineering     Hybrid Journal  
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 4)
International Journal of Manufacturing Research     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 7)
International Journal of Materials and Product Technology     Hybrid Journal   (Followers: 4)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 7)
International Journal of Mathematics in Operational Research     Hybrid Journal   (Followers: 1)
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 5)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 4)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Microwave Science and Technology     Open Access   (Followers: 2)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 3)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 2)
International Journal of Nanomanufacturing     Hybrid Journal   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 2)
International Journal of Navigation and Observation     Open Access   (Followers: 6)
International Journal of Network Management     Hybrid Journal  
International Journal of Nonlinear Sciences and Numerical Simulation     Full-text available via subscription  
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 7)
International Journal of Optics     Open Access   (Followers: 1)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 9)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 2)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 3)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal  
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 4)
International Journal of Polymer Science     Open Access   (Followers: 16)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 5)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 2)
International Journal of Production Economics     Hybrid Journal   (Followers: 12)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 4)
International Journal of Quality Assurance in Engineering and Technology Education     Full-text available via subscription   (Followers: 2)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 1)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 6)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 8)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 2)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 1)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal  
International Journal of Social Robotics     Hybrid Journal   (Followers: 1)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 1)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 2)
International Journal of Speech Technology     Hybrid Journal   (Followers: 3)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 6)
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Systems and Service-Oriented Engineering     Full-text available via subscription  
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal of Technoethics     Full-text available via subscription  
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 4)
International Journal of Telemedicine and Applications     Open Access   (Followers: 2)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 5)
International Journal of Thermodynamics     Open Access   (Followers: 2)
International Journal of Turbo & Jet-Engines     Full-text available via subscription  
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal   (Followers: 1)
International Journal of Vehicle Design     Hybrid Journal   (Followers: 6)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 3)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 5)
International Journal of Vehicular Technology     Open Access   (Followers: 2)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 4)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal  
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 4)
International Nano Letters     Open Access   (Followers: 8)
International Review of Applied Sciences and Engineering     Full-text available via subscription  
Inverse Problems in Science and Engineering     Hybrid Journal   (Followers: 2)
Ionics     Hybrid Journal  
IPTEK The Journal for Technology and Science     Open Access  
IRBM News     Full-text available via subscription  
Irrigation and Drainage Systems     Hybrid Journal  
ISA Transactions     Full-text available via subscription   (Followers: 1)
ISRN - International Scholarly Research Notices     Open Access   (Followers: 69)
ISRN Nanotechnology     Open Access  
ISRN Signal Processing     Open Access  
ISRN Thermodynamics     Open Access  
IT Professional     Full-text available via subscription   (Followers: 3)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 1)
Journal of Advanced Manufacturing Systems     Hybrid Journal   (Followers: 6)
Journal of Aerosol Science     Hybrid Journal   (Followers: 1)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 153)
Journal of Alloys and Compounds     Hybrid Journal   (Followers: 8)
Journal of Analytical and Applied Pyrolysis     Hybrid Journal   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 4)
Journal of Analytical Sciences, Methods and Instrumentation     Open Access   (Followers: 1)
Journal of Applied Analysis     Full-text available via subscription  
Journal of Applied and Industrial Sciences     Open Access  
Journal of Applied Logic     Full-text available via subscription  

  First | 2 3 4 5 6 7 8 9 | Last

Journal of Computational and Nonlinear Dynamics
   [8 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 1555-1415 - ISSN (Online) 1555-1423
     Published by ASME International Homepage  [25 journals]   [SJR: 0.606]   [H-I: 17]
  • Singularities in Differential-Algebraic Boundary-Value Problems Governing
           the Excitation Response of Beam Structures
    • Authors: Saghafi M; Dankowicz H.
      Abstract: The objective of this paper22 is to identify and, where possible, resolve singularities that may arise in the discretization of spatiotemporal boundary-value problems governing the steady-state behavior of nonlinear beam structures. Of particular interest is the formulation of nondegenerate continuation problems of a geometrically-nonlinear model of a slender beam, subject to a uniform harmonic excitation, which may be analyzed numerically in order to explore the parameter-dependence of the excitation response. In the instances of degeneracy investigated here, the source is either found (i) directly in a differential-algebraic system of equations obtained from a finite-element-based spatial discretization of the governing partial differential boundary-value problem(s) together with constraints on the trial functions or (ii) in the further collocation-based discretization of the time-periodic boundary-value problem. It is shown that several candidate spatial finite-element discretizations of a mixed weak formulation of the governing boundary-value problem either result in (i) spatial group symmetries corresponding to equivariant vector fields and one-parameter families of periodic orbits along the group symmetry orbit or (ii) temporal group symmetries corresponding to ghost solutions and indeterminacy in a subset of the field variables. The paper demonstrates several methods for breaking the spatial equivariance, including projection onto a symmetry-reduced state space or the introduction of an artificial continuation parameter. Similarly, the temporal indeterminacy is resolved by an asymmetric discretization of the governing differential-algebraic equations. Finally, in the absence of theoretical bounds, computation is used to estimate convergence rates of the different discretization schemes, in the case of numerical calibration experiments performed on equilibrium and periodic responses for a linear beam, as well as for the full nonlinear models.
      PubDate: Tue, 14 Oct 2014 00:00:00 GMT
       
  • Excitation-Induced Stability in a Bistable Duffing Oscillator: Analysis
           and Experiments
    • Authors: Wu ZZ; Harne RL, Wang KW.
      Abstract: The excitation-induced stability (EIS) phenomenon in a harmonically excited bistable Duffing oscillator is studied in this paper. Criteria to predict system and excitation conditions necessary to maintain EIS are derived through a combination of the method of harmonic balance, perturbation theory, and stability theory for Mathieu's equation. Accuracy of the criteria is verified by analytical and numerical studies. We demonstrate that damping primarily determines the likelihood of attaining EIS response when several dynamics coexist while excitation level governs both the existence and frequency range of the EIS region, providing comprehensive guidance for realizing or avoiding EIS dynamics. Experimental results are in good agreement regarding the comprehensive influence of excitation conditions on the inducement of EIS.
      PubDate: Tue, 14 Oct 2014 00:00:00 GMT
       
  • Energy Considerations for Mechanical Fractional-Order Elements
    • Authors: Lorenzo CF; Hartley TT.
      Abstract: This paper considers the energy aspects of fractional-order elements defined by the equation: force is proportional to the fractional-order derivative of displacement, with order varying from zero to two. In contrast to the typically conservative assumption of classical physics that leads to the potential and kinetic energy expressions, a number of important nonconservative differences are exposed. Firstly, the considerations must be time-based rather than displacement or momentum based variables. Time based equations for energy behavior of fractional elements are presented and example applications are considered. The effect of fractional order on the energy input and energy return of these systems is shown. Importantly, it is shown that the history, or initialization, has a significant effect on energy response. Finally, compact expressions for the work or energy, are developed.
      PubDate: Mon, 13 Oct 2014 00:00:00 GMT
       
  • Asymmetric Magnet-Based Nonlinear Energy Sink
    • Authors: AL-Shudeifat MA.
      Abstract: The nonlinear energy sink (NES) is a light-weighted device used for shock mitigation in dynamic structures through its passive targeted energy transfer (TET) mechanism. Here, a new design for the NES is introduced based on using an asymmetric NES force. This force is strongly nonlinear in one side of the NES equilibrium position, whereas it is either weakly nonlinear or weakly linear in the other side. This is achieved by introducing the asymmetric magnet-based NES in which the asymmetric nonlinear magnetic repulsive force is generated by two pairs of aligned permanent magnets. Consequently, this proposed design is found to provide a considerable enhancement in the shock mitigation performance compared with the symmetric stiffness-based NESs for broadband energy inputs.
      PubDate: Mon, 13 Oct 2014 00:00:00 GMT
       
  • Modeling Flexibility in Myosin V Using a Multiscale Articulated
           Multi-Rigid Body Approach
    • Authors: Haghshenas-Jaryani M; Bowling A.
      Abstract: This paper presents a multiscale dynamic model for the simulation and analysis of flexibility in myosin V. A 3D finite segment model, a multirigid body model connected with torsional springs, is developed to mechanically model the biological structure of myosin V. The long simulation run time is one of the most important issues in the dynamic modeling of biomolecules and proteins due to the disproportionality between the physical parameters involved in their dynamics. In order to address this issue, the most-used models, based on the famous overdamped Langevin equation, omit the inertial terms in the equations of motion; that leads to a first order model that is inconsistent with Newton's second law. However, the proposed model uses the concept of the method of multiple scales (MMS) that brings all of the terms of the equations of motion into proportion with each other; that helps to retain the inertia terms. This keeps the consistency of the model with the physical laws and experimental observations. In addition, the numerical integration's step size can be increased from commonly used subfemtoseconds to submilliseconds. Therefore, the simulation run time is significantly reduced in comparison with other approaches. The simulation results obtained by the proposed multiscale model show a dynamic behavior of myosin V which is more consistent with experimental observations in comparison with other overdamped models.
      PubDate: Mon, 13 Oct 2014 00:00:00 GMT
       
  • Numerical Detection of Stochastic to Deterministic Transition
    • Authors: Brojen Singh RK.
      Abstract: We present the numerical estimation of noise parameter induced in the dynamics of the variables by random particle interactions involved in the stochastic chemical oscillator and use it as order parameter to detect the transition from stochastic to deterministic regime. In stochastic regime, this noise parameter is found to be increased as system size decreases, whereas in deterministic regime it remains constant to minimum value as system size increases. This let the transition from fluctuating to fixed limit cycle oscillation as the system goes from stochastic to deterministic transition. We also numerically estimated the strength of the noise parameter involved both in chemical Langevin equation and Master equation formalisms and found that strength of this parameter is much smaller in the former than the latter.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Performance of a Method for Formulating Geometrically Exact
           Complementarity Constraints in Multibody Dynamic Simulation
    • Authors: Montrallo Flickinger D; Williams J, Trinkle JC.
      Abstract: Contemporary problem formulation methods used in the dynamic simulation of rigid bodies suffer from problems in accuracy, performance, and robustness. Significant allowances for parameter tuning, coupled with careful implementation of a broad-phase collision detection scheme are required to make dynamic simulation useful for practical applications. A constraint formulation method is presented herein that is more robust, and not dependent on broad-phase collision detection or system tuning for its behavior. Several uncomplicated benchmark examples are presented to give an analysis and make a comparison of the new polyhedral exact geometry (PEG) method with the well-known Stewart–Trinkle method. The behavior and performance for the two methods are discussed. This includes specific cases where contemporary methods fail to match theorized and observed system states in simulation, and how they are ameliorated by the new method presented here. The goal of this work is to complete the groundwork for further research into high performance simulation.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Robust Stabilization of a Class of Nonaffine Quadratic Polynomial Systems:
           Application in Magnetic Ball Levitation System
    • Authors: Binazadeh TT; Shafiei MH, Rahgoshay MA.
      Abstract: In this paper, a new approach is suggested for asymptotic stabilization of a class of nonaffine quadratic polynomial systems in the presence of uncertainties. The designed controller is based on the sliding mode (SM) technique. This technique is basically introduced for nonlinear affine systems and in facing with nonaffine systems; attempts have been made to transform the system into an affine form. Lake of robustness is the main problem of the transformation approach. In this paper, a simple but effective idea is suggested to stabilize a system in its nonaffine structure and, therefore, a nonrobust transformation is not needed. In the proposed method, according to upper and lower bounds of uncertainties, two quadratic polynomials are constructed and with respect to the position of the roots of these polynomials, a new SM controller is proposed. This idea is also used for robust stabilization of a practical nonaffine quadratic polynomial system (magnetic ball levitation system). Computer simulations show the efficiency of the proposed control law.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Dynamic Analysis of Cable-Driven Parallel Manipulators Using a Variable
           Length Finite Element
    • Authors: Du J; Cui C, Bao H, et al.
      Abstract: Cable-driven parallel manipulator (CDPM) is a good solution to achieving large workspace. However, unavoidable vibrations of long cables can dramatically degrade the positioning performance in large workspace applications. Most work so far on cable-driven parallel manipulators (CDPMs) simply neglected the dynamics of the cables themselves. In this paper dynamic modeling of large CDPMs is addressed using a variable domain finite element method (FEM). A cable element with variable length is derived using the absolute nodal coordinate formulation to facilitate motion analysis of CDPMs. The effects of cable length variation and the resulting mass variation are also considered. Based on this element dynamics model of CDPMs can be readily obtained using the standard assembling operation in the FEM. Numerical results showed that the effect of the derivatives of cable length variation and that of the mass variation are trivial.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Direct and Adjoint Sensitivity Analysis of Ordinary Differential Equation
           Multibody Formulations
    • Authors: Dopico D; Zhu Y, Sandu A, et al.
      Abstract: Sensitivity analysis of multibody systems is essential for several applications, such as dynamics-based design optimization. Dynamic sensitivities, when needed, are often calculated by means of finite differences. This procedure is computationally expensive when the number of parameters is large, and numerical errors can severely limit its accuracy. This paper explores several analytical approaches to perform sensitivity analysis of multibody systems. Direct and adjoint sensitivity equations are developed in the context of Maggi's formulation of multibody dynamics equations. The approach can be generalized to other formulations of multibody dynamics as systems of ordinary differential equations (ODEs). The sensitivity equations are validated numerically against the third party code fatode and against finite difference solutions with real and complex perturbations.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Gear Dynamics Analysis With Turbulent Journal Bearings Mounted Hybrid
           Squeeze Film Damper—Chaos and Active Control Analysis
    • Authors: Chang-Jian C.
      Abstract: The hybrid squeeze film damper mounted turbulent journal bearing–gear system is proposed in this paper. The nonlinear dynamics of a gear pair supported by such bearing is studied. Numerical results show that, due to the nonlinear factors of lubricant film force, the trajectory of the pinion demonstrates a complex dynamics with dimensionless unbalance parameters. Poincaré maps and bifurcation diagrams are used to analyze the behavior of the pinion trajectory in the horizontal direction. The maximum Lyapunov exponent is used to determine if the system is in a state of chaotic motion. In order to avoid the nonsynchronous chaotic vibrations, an increased proportional gain kp = 0.1 is applied to control this system. It is shown that the pinion trajectory will leave chaotic motion to periodic motion in the steady state under control action.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Nonlinear Reduced Order Models for the Structural Dynamics of Combustor
           Systems With Prestress and Friction
    • Authors: Jung C; Epureanu BI, Baik S, et al.
      Abstract: An efficient methodology to capture the nonlinear responses of combustor systems with prestress and Coulomb friction is developed. The combustor systems experience wear at the interfaces between components due to flow-induced vibrations. In particular, wear has been observed at the interface between the transition piece and the hula seal, and at the interface between the hula seal and the liner. These interfaces are prestressed, and their vibratory response has a softening nonlinearity caused by Coulomb friction combined with microslip. In addition, the contact between the hula seal and the transition piece is that between a convex surface and a concave surface. Hence, geometric nonlinearity of the contact stiffness in the normal direction is present also. These phenomena are hard to capture by full-order finite element (FE) approaches because they require time marching or harmonic balancing of very large models. To address this issue, we develop reduced order models (ROMs) which are specifically designed to capture Coulomb friction (combined with micro- and macroslip). To demonstrate the proposed approach, a simplified hula seal is placed between two very rigid plates (which relate to the transition piece and the liner). For validation, contact elements are used to model the interface between the plates and the hula seal. Transient dynamic analysis (TDA) in ansys is applied to the full-order model. The model is shown to exhibit softening nonlinearity and microslip at all levels of prestress. To show that ROMs for this system are possible (i.e., they exist), we use proper orthogonal decomposition (POD) to show that the dynamics is dominated by a low number of spatial coherences. For a variety of frequency ranges and prestress levels, we show that a single such coherence is dominant. Next, low order models are proposed and their parameters are identified. A systematic method to identify these parameters is developed. Particular attention is paid to the amount of calculations needed for obtaining these parameters. Finally, the ROMs are validated by comparing their predictions with results from TDA for the full-order model. We show that these ROMs can accurately predict the nonlinear response of the system.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Control of Discrete Time Chaotic Systems via Combination of Linear and
           Nonlinear Dynamic Programming
    • Authors: Merat K; Abbaszadeh Chekan J, Salarieh H, et al.
      Abstract: In this article by introducing and subsequently applying the Min–Max method, chaos has been suppressed in discrete time systems. By using this nonlinear technique, the chaotic behavior of Behrens–Feichtinger model is stabilized on its first and second-order unstable fixed points (UFP) in presence and absence of noise signal. In this step, a comparison has also been carried out among the proposed Min–Max controller and the Pyragas delayed feedback control method. Next, to reduce the computation required for controller design, the clustering method has been introduced as a quantization method in the Min–Max control approach. To improve the performance of the acquired controller through clustering method obtained with the Min–Max method, a linear optimal controller is also introduced and combined with the previously discussed nonlinear control law. The resultant combined controller has been applied on the Henon map and through comparison with both Pyragas controller, and the linear optimal controller alone, its advantages are discussed.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Dynamics of a Linear Oscillator Coupled to a Bistable Light Attachment:
           Numerical Study
    • Authors: Romeo F; Sigalov G, Bergman LA, et al.
      Abstract: The conservative and dissipative dynamics of a 2DOF, system composed of a grounded linear oscillator coupled to a lightweight mass by means of both strongly nonlinear and linear negative stiffnesses is investigated. Numerical studies are presented aiming to assess the influence of this combined coupling on the transient dynamics. In particular, these studies are focused on passive nonlinear targeted energy transfer from the impulsively excited linear oscillator to the nonlinear bistable lightweight attachment. It is shown that the main feature of the proposed configuration is the ability of assuring broadband efficient energy transfer over a broad range of input energy. Due to the bistability of the attachment, such favorable behavior is triggered by different nonlinear dynamic mechanisms depending on the energy level. For high energy levels, strongly modulated oscillations occur, and the dynamics is governed by fundamental (1:1) and superharmonic (1:3) resonances; for low energy levels, chaotic cross-well oscillations of the nonlinear attachment as well as subharmonic resonances lead to strong energy exchanges between the two oscillators. The results reported in this work indicate that properly designed attachments of this type can be efficient absorbers and dissipators of impulsively induced vibration energy.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Dynamics and Control of a Planar Multibody Mobile Robot for Confined
           Environment Inspection
    • Authors: Douadi L; Spinello D, Gueaieb W.
      Abstract: In this paper, we study the dynamics of an articulated planar mobile robot for confined environment exploration. The mobile vehicle is composed of n identical modules hitched together with passive revolute joints. Each module has the structure of a four-bar parallel mechanism on a mobile platform. The dynamic model is derived using Lagrange formulation. Computer simulations illustrate the model by addressing a path following problem inside a pipe. The dynamic model presented in this paper is the basis for the design of motion control algorithms that encode energy optimization and sensor performance maximization.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Wavelet-Based Multifractal Analysis to Periodic Time Series
    • Authors: Chen C; Wang Z, Gou Y, et al.
      Abstract: Many processes are characterized by their oscillating or cyclic time behavior. This holds for rotating machines or alternating currents. The resulting signals are then periodic signals or contain periodic parts. It can be used for fault detection of rotating machines. In this paper, we studied the periodic time series of the superposition of two oscillations from the multifractal point of view. The wavelet transform modulus maxima method was used for the singularity spectrum computations. The results show that the width and the peak position of the singularity spectrum changed significantly when the amplitude, frequency, or the phase difference changed. So, the width and the peak position of the singularity spectrum can be used as a new measure for periodic signals.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Computing Numerical Solutions of Delayed Fractional Differential Equations
           With Time Varying Coefficients
    • Authors: Suresh Deshmukh V.
      Abstract: Fractional differential equations with time varying coefficients and delay are encountered in the analysis of models of metal cutting processes such as milling and drilling with viscoelastic damping elements. Viscoelastic damping is modeled as a fractional derivative. In the present paper, delayed fractional differential equations with bounded time varying coefficients in four different forms are analyzed using series solution and Chebyshev spectral collocation. A fractional differential equation with a known exact solution is then solved by the methodology presented in the paper. The agreement between the two is found to be excellent in terms of point-wise error in the trajectories. Solutions to the described fractional differential equations are computed next in state space and second order forms.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Dexterity and Adaptive Control of Planar Parallel Manipulators With and
           Without Redundant Actuation
    • Authors: Shang W; Cong S.
      Abstract: The objective of this paper is to determine whether a planar parallel manipulator with redundant actuation has better tracking accuracy than a planar parallel manipulator without redundant actuation. The effects of the redundant actuation on tracking accuracy of parallel manipulators are studied by using two different experimental platforms. The first platform is the planar five-bar parallel manipulator with normal actuation, and the other one is the planar parallel manipulator with redundant actuation. The dexterity pictures and the kinematic configurations of the two platforms validate the kinematic advantages from the redundant actuation. In order to study the dynamic advantages of the redundant actuation further, a nonlinear adaptive controller is presented for the two platforms. The experimental comparison is implemented on two actual parallel manipulator platforms, and from the experimental results, one can find the tracking accuracy of the parallel manipulator with redundant actuation can be improved above 38% than that of the five-bar parallel manipulator without redundant actuation.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
  • Synchronization and Antisynchronization of a Class of Chaotic Systems With
           Nonidentical Orders and Uncertain Parameters
    • Authors: Chen D; Zhao W, Liu X, et al.
      Abstract: In this paper, we study the synchronization of a class of uncertain chaotic systems. Based on the sliding mode control and stability theory in fractional calculus, a new controller is designed to achieve synchronization. Examples are presented to illustrate the effectiveness of the proposed controller, like the synchronization between an integer-order system and a fraction-order system, the synchronization between two fractional-order hyperchaotic systems (FOHS) with nonidentical fractional orders, the antisynchronization between an integer-order system and a fraction-order system, the synchronization between two new nonautonomous systems. The simulation results are in good agreement with the theory analysis and it is noted that the proposed control method is of vital importance for practical system parameters are uncertain and imprecise.
      PubDate: Fri, 12 Sep 2014 00:00:00 GMT
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2014