首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Dynamic architecture of multi-agent systems （MAS） is important for critical systems. As the existing formal specifications of MAS cannot describe its dynamic architecture, a formal approach using n-calculus is presented, which is suited for the describing and analyzing of concurrent MAS with dynamic topology, n-calculus describes the belief-desireintention （BDI） model that represents agent＇s mental states and provides many useful facilities to analyze MAS model such as deadlock, behavior equivalence, and model checking. To illustrate the favorable representation capability of n-calculus, an example of dynamic multi-agent systems in e-commerce is provided. Finally, by using an existing n-calculus supporting tool, MAS model and some key behaviors properties are analyzed and verified.  相似文献   

2.
  相似文献   

3.
This paper develops a unified methodology for a real-time speed control of brushless direct-current motor drive systems in the presence of measurement noise and load torque disturbance. First, the mathematical model and hardware structure of system is established. Next, an optimal state feed back controller using the Kalman filter state estimation technique is derived. This is followed by an adaptive control algorithm to compensate for the effects of noise and disturbance. Those two algorithms working together can provide a very-high-speed regulation and dynamic response over a wide range of operating conditions. Simulated responses are presented to highlight the effectiveness of the proposed control strategy.  相似文献   

4.
Modeling of D-STATCOM in distribution systems load flow   总被引：1，自引：0，他引：1  
This paper presents modeling of Distribution STATCOM (D-STATCOM) in load flow calculations for the steady- state voltage compensation. An accurate model for D-STATCOM is derived to use in load flow calculations. The rating of this device as well as the direction of required reactive power injection for voltage compensation in the desired value (1 p.u.) is de- rived and discussed analytically and mathematically by the phasor diagram method. Furthermore, an efficient method for node and line identification used in load flow calculations is presented. The validity of the proposed model is examined by using two standard distribution systems consisting of 33 and 69 nodes, respectively. The best location of D-STATCOM for under voltage problem mitigation approach in the distribution networks is determined. The results validate the proposed model for D- STATCOM in large distribution systems.  相似文献   

5.
Graph transformation systems have become a general formal modeling language to describe many models in software development process. Behavioral modeling of dynamic systems and model-to-model transformations are only a few examples in which graphs have been used to software development. But even the perfect graph transformation system must be equipped with automated analysis capabilities to let users understand whether such a formal specification fulfills their requirements. In this paper, we present a new solution to verify graph transformation systems using the Bogor model checker. The attributed graph grammars （AGG）-like graph transformation systems are translated to Bandera intermediate representation （BIR）, the input language of Bogor, and Bogor verifies the model against some interesting properties defined by combining linear temporal logic （LTL） and special-purpose graph rules. Experimental results are encouraging, showing that in most cases our solution improves existing approaches in terms of both performance and expressiveness.  相似文献   

6.
This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of motion are solved by using the HilberHughes-Taylor (HHT) time integration method. Firstly, the static damage response analysis of the hydropower station is conducted due to high tensile stress resulting from large water head and diameter of an inlet pipe. Then, on the basis of static simulation, the dynamic damage analysis of hydropower house subjected to earthquake motion is simulated. Numerical results show that under large water head and diameter of an inlet pipe of the project, the damages are mainly located near the top of the spiral case from the inlet section to the 0° section; under combined loadings of static loads and earthquake, the damages of the concrete surrounding the spiral case increase insignificantly; however, some damages occur on the side walls of the main powerhouse.  相似文献   

7.
The dynamic power management for embedded system with Poisson process   总被引：1，自引：0，他引：1  
The mass of the embedded systems are driven by second batteries, not by wired power supply. So saving energy is one of the main design goals for embedded system. In this paper we present a new technique for modelling and solving the dynamic power management （DPM） problem for embedded systems with complex behavioural characteristics. First we model a power-managed embedded computing system as a controllable Flow Chart. Then we use the Poisson process for optimisation, and give the power management algorithm by the help of Dynamic Voltage Scaling （DVS） technology. At last we built the experimental model using the PXA 255 Processors. The experimental results showed that the proposed technique can achieve more than 12% power saving compared to other existing DPM techniques.  相似文献   

8.
Wind energy is one of the fast growing sources of power production currently, and there is a great demand to reduce the cost of operation and maintenance. Most wind farms have installed supervisory control and data acquisition （SCADA） systems for system control and logging data. However, the collected data are not used effectively. This paper proposes a fault detection method for main bearing wind turbine based on existing SCADA data using an artificial neural network （ANN）. The ANN model for the normal behavior is established, and the difference between theoretical and actual values of the parameters is then calculated. Thus the early stage of main bearing fault can be identified to let the operator have sufficient time to make more informed decisions for maintenance.  相似文献   

9.
In this paper modelling of the translational motion of transportation rail-guided cart with rope suspended payload is considered. The linearly moving cart,driven by a travel mechanism,is modelled as a discrete six degrees of freedom (DOF) dynamic system. The hoisting mechanism for lowering and lifting the payload is considered and is included in the dynamic model as one DOF system. Differential equations of motion of the cart elements are derived using Lagrangian dynamics and are solved for a set of real-life constant parameters of the cart. A two-sided interaction was observed between the swinging payload and the travel mechanism. Results for kinematical and force parameters of the system are obtained. A verification of the proposed model was conducted.  相似文献   

10.
Traditional studies on integrated statistical process control and engineering process control (SPC-EPC) are based on linear autoregressive integrated moving average (ARIMA) time series models to describe the dynamic noise of the system.However,linear models sometimes are unable to model complex nonlinear autocorrelation.To solve this problem,this paper presents an integrated SPC-EPC method based on smooth transition autoregressive (STAR) time series model,and builds a minimum mean squared error (MMSE) controller as well as an integrated SPC-EPC control system.The performance of this method for checking the trend and sustained shift is analyzed.The simulation results indicate that this integrated SPC-EPC control method based on STAR model is effective in controlling complex nonlinear systems.  相似文献   

11.
INTRODUCTION The propagation of stress-waves in an elasticmedium containing a cavity that are due to arbitrarydynamic loading applied on the cavity is of greatimportance in the fields of seismology, geophysicalprospecting, underground tunnels and deeply buriedpipelines, particularly as a model of an earthquakesource. Ben-Menahem and Cisternas (1963) devel-oped the theory for the dynamic response of an elastichalf-space medium to an explosion spherical cavity.Norwood and Miklowitz (…  相似文献   

12.
The robust exponential stability of a larger class of discrete-time recurrent neural networks (RNNs) is explored in this paper. A novel neural network model, named standard neural network model (SNNM), is introduced to provide a general framework for stability analysis of RNNs. Most of the existing RNNs can be transformed into SNNMs to be analyzed in a unified way. Applying Lyapunov stability theory method and S-Procedure technique, two useful criteria of robust exponential stability for the discrete-time SNNMs are derived. The conditions presented are formulated as linear matrix inequalities (LMIs) to be easily solved using existing efficient convex optimization techniques. An example is presented to demonstrate the transformation procedure and the effectiveness of the results.  相似文献   

13.
To overcome the deficiencies of the existing Verhulst GM(1,1) model, based on the existing grey theory, a non-equal-interval direct optimum Verhulst GM(1,1) model is built which chooses a modified n-th component x(n) of X(0) as the starting condition of the grey differential model. It optimizes a modified β value and the background value, and takes two times fitting optimization. The new model extends equal intervals to non-equal-intervals and is suitable for general data modelling and estimating parameters...  相似文献   

14.
Computational grids(CGs)aim to offer pervasive access to a diverse collection of geographically distributed resources owned by different self-interested agents or organizations.These agents may manipulate the resource allocation algorithm in their own benefit,and their selfish behavior may lead to severe performance degradation and poor efficiency. In this paper,game theory is introduced to solve the problem of barging for resource collection in heterogeneous distributed systems.By using the Cournot model that is an important model in static and complete information games,the algorithm is optimized in order to maximize the benefit.It can be seen that the approach is more suitable to the real situation and has practical use.Validity of the solutions is shown.  相似文献   

15.
We studied the feedback maximization of reliability of multi-degree-of-freedom （MDOF） quasi integrable-Hamiltonian systems under combined harmonic and white noise excitations. First, the partially averaged Ito equations are derived by using the stochastic averaging method for quasi integrable-Hamiltonian systems under combined harmonic and white noise excitations. Then, the dynamical programming equation and its boundary and final time conditions for the control problems of maximizing the reliability is established from the partially averaged equations by using the dynamical programming principle. The nonlinear stochastic optimal control for maximizing the reliability is determined from the dynamical programming equation and control constrains. The reliability function of optimally controlled systems is obtained by solving the final dynamical programming equation. Finally, the application of the proposed procedure and effectiveness of the control strategy are illustrated by using an example.  相似文献   

16.
Future multimedia communication systems have to support the user‘s needs, the terminal capabilities, the content specification and the underlying networking technologies. The related protocols and applications must be designed from this integration perspective in a cross-layer centric manner. In this paper, we propose an implementation of a streaming service (e.g.,Television over IP service) with a unified QoS management concept that enables an IP driven integration of different system components (terminal, user, content, and network). The MPEG-21 framework is used to provide a common support for implementing and managing the end-to-end QoS. The main focus of this paper is on the architecture design, protocols specification and implementation evaluation. Performance evaluations using PSNR and SSIM objective video quality metrics show the benefit of the proposed MPEG-21-enabled cross-layer adaptation.  相似文献   

17.
In order to evaluate the capacity of reinforced concrete (RC) structures subjected to blast loadings,the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC structures,and all three failure modes were numerically simulated by the finite element software ABAQUS.Simulation results agree with the experimental observations.It is demonstrated that the damaged plasticity model for concrete in the finite element software ABAQUS can predict dynamic responses and typical flexure,flexure-shear and direct shear failure modes of the blast-loaded RC structures.  相似文献   

18.
  相似文献   

19.
This paper presents an efficient and reliable genetic algorithm (GA) based particle swarm optimization (PSO) tech- nique (hybrid GAPSO) for solving the economic dispatch (ED) problem in power systems. The non-linear characteristics of the generators, such as prohibited operating zones, ramp rate limits and non-smooth cost functions of the practical generator operation are considered. The proposed hybrid algorithm is demonstrated for three different systems and the performance is compared with the GA and PSO in terms of solution quality and computation efficiency. Comparison of results proved that the proposed algo- rithm can obtain higher quality solutions efficiently in ED problems. A comprehensive software package is developed using MATLAB.  相似文献   

20.
It is inevitable that as a result of progress in technology and the changes in the ways with which design is conceived, interior architecture schools should be updated according to these requirements and that new educational processes should be tried out. It is for this reason that the scope and aim of this study have been determined as being the formulation of a hybrid educational model for the integration of digital approaches to design within the interior architecture education system. Within the chosen scope and aim of this study, and as a methodology, various algorithmic and parametric approaches have been applied in various practical applications as digital design instruments, and conclusions have been reached concerning the advantages they offer within the design process. The advantages and disadvantages, concerning interior architecture education, of digital approaches to design over the traditional design method, have been presented on the basis of results found during practical applications of digital design, the information found in publications about this subject. A hybrid educational model for the restructuring with digital design instruments of interior architecture education and design studios as experimental areas has been presented. Thanks to this proposed model, the establishment of a computer formatted analytic design system in the guise of dynamic systems will get easier and, the opportunity of restructuring the process and conception of design will also present itself. As the effects of this method are reflected on the products, new geometric approaches and typologies will appear, with the result that designs and digital instruments will constantly be developed and will evolve. In conclusion, educating the designers of the future according to the essence of these approaches will make it possible to train professionals who correctly use and understand the technologies being developed, who have a critical stance, and who can produce renewable designs.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号