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Identifying dynamic systems with polynomial nonlinearities in the errors-in-variables context

WSEAS Transactions on Systems 2009年第7期8卷 793-802页

作者： Hunyadi, Levente Vajk, István Budapest University of Technology and Economics Department of Automation and Applied Informatics Goldmann György tér 3 1111 Budapest Hungary

Many practical applications including speech and audio processing, signal processing, system identification, econometrics and time series analysis involve the problem of reconstructing a dynamic system model from data observed with noise in all variables. We consider an important class of dynamic single-input single-output nonlinear systems where the system model is polynomial in observations but linear in parameters, which captures a wide range of such systems. Assuming white Gaussian measurement noise that is characterized by a magnitude and a covariance structure, we propose a nonlinear extension to the generalized Koopmans-Levin method that can estimate parameters of dynamic nonlinear systems with polynomial nonlinearities given a priori knowledge on the noise covariance structure. In order to estimate noise structure, we apply a covariance matching objective function. Combining the extended Koopmans-Levin and the covariance matching approaches, an identification algorithm to estimate both model and noise parameters is proposed. The feasibility of the approach is demonstrated by Monte-Carlo simulations.

关键词： Nonlinear systems

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Overall Delay in IEEE 802.16 with Contention-Based Random Access

Overall Delay in IEEE 802.16 with Contention-Based Random Ac...

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16th International Conference on Analytical and Stochastic Modeling Techniques and Applications

作者： Andreev, Sergey Saffer, Zsolt Turlikov, Andrey Vinel, Alexey State University of Aerospace Instrumentation (SUAI) Russian Federation Department of Telecommunications Budapest University of Technology and Economics (BUTE) Hungary St.Petersburg Institute for Informatics and Automation of RAS (SPIIRAS) Russian Federation

ISBN: (纸本)9783642022043

In this paper we address the overall message delay analysis of IEEE 802.16 wireless metropolitan area network with contention-based multiple access of bandwidth requests. The overall delay consists of the reservation and scheduling components. Broadcast polling is used for bandwidth reservation with binary exponential backoff (BEB) collision resolution protocol and a simple scheduling is applied at;the base station. An analytical model is developed with Poisson arrival flow for the Non Real-Time Polling Service (nrtPS) class. The model enables asymmetric traffic flows, different message sizes at the subscriber stations Old also allows for Best Effort (BE) service class. An approximation of the mean overall delay is established for the nrtPS service class. The analytical Model is verified by Means Of simulation.

关键词： IEEE 802.16 WMAN performance evaluation bandwidth reservation contention-based multiple access BEB queueing model

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Electronic mail-based adaptive social graph for the conference

Electronic mail-based adaptive social graph for the conferen...

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International Workshop on Soft Computing Applications (SOFA)

作者： Gabor Tolnai Department of Automation and Applied Informatics Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

In the last few years many Web sites were created to build social networks. These sites have common behavior, for example they need their users to search and mark their friends, so those are the users who build the graph themselves. This graph is fixed from a certain point of view: the connections are binary connections and the graph consists of only the explicit data given by the users. In this paper we define a social network based on e-mails which is distributed and asymmetric. The key differences between this type of network and usual networks are that using this network we do not need to register to a specific Web site and we do not need to mark our friends. The social graph can be built automatically based on the mass of e-mails and the address book belonging to us. By analyzing this huge amount of data we can reveal the connections between our contacts and build a weighted graph. Besides this we can create a graph from the e-mails using the same data to improve the search results when looking for a specific e-mail or contact. These weighted graphs can be considered as neural networks. We can create an adaptive method to modify the connections in the graphs with implicit data gathered from the behavior of the user. Moreover, we can define a search algorithm on this type of graph based on the activation model of the neural networks. In this paper we show a way to build this kind of networks and we define an algorithm which finds similar elements to a specific item.

关键词： Electronic mail Social network services Books Neural networks automation informatics IP networks Internet Protocols Message service

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Decentralized, agent-based control of low and moderate power DC-DC converters

Decentralized, agent-based control of low and moderate power...

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Brazilian Power Electronics Conference, COBEP

作者： Janos Hamar Department of Automation and Applied Informatics Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

An agent-based decentralized control of dual channel, isolated resonant dc-dc converters is presented. Discrete-time control will be implemented in the control agents. Selection process of the most suitable converter ... 详细信息

关键词： DC-DC power converters Switches Automatic control Resonance Voltage Buck converters Tin automation informatics Isolation technology

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Agent-based control of parallel dc-dc converters

Agent-based control of parallel dc-dc converters

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European Conference on Power Electronics and Applications

作者： J. Hamar A. Toth Department of Automation and Applied Informatics Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

ISBN: (纸本)9781424444328

The paper describes a new agent-based, decentralized architecture and control for parallel dc-dc converters, supplying low and moderate power consumers in the range of 0-250 W. The system provides increased flexibility with autonomic system reconstruction capability in the case of misoperation or fault, significantly contributing to the increase of reliability. The distributed intelligence facilitates the optimization of the converters' operation according to predefined criteria.

关键词： DC-DC power converters Power system reliability Control systems Distributed control Switches Switching converters Manufacturing Power supplies Costs Centralized control

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Identification of crosscutting constraints in metamodel-based model transformations

Identification of crosscutting constraints in metamodel-base...

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Eurocon

作者： Laszlo Lengyel Tihamer Levendovszky Laszlo Angyal Department of Automation and Applied Informatics Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

This Model-Driven Development (MDD) facilitates the synthesis of application programs from models created using customized, domain-specific model processors. Model compilers can be realized by graph rewriting-based model transformation. In Visual Modeling and Transformation System (VMTS), metamodel-based rewriting rules facilitate to assign OCL constraints to model transformation rules. This approach supports validated model transformation. Unfortunately, the validation introduces a new concern that often crosscuts the functional concern of the transformation rules. To separate these concerns, an aspect-oriented solution is applied for constraint management. This paper introduces the identification method of the crosscutting constraints in metamodel-based model transformation rules. The presented algorithms facilitate the better understanding of the transformation, their easier constraint-based configuration, and make both the constraints and the rewriting rules reusable.

关键词： Algorithm design and analysis System testing Weaving Programming Time factors automation informatics Microwave integrated circuits Computer architecture Genetic mutations

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Delay propagation in a real life railway network controlled by a fuzzy logic rule base

Delay propagation in a real life railway network controlled ...

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10th International Symposium of Hungarian Researchers on Computational Intelligence and informatics, CINTI 2009

作者： Farkas, Mark Héray, Tibor Rózsa, Gábor Kóczy, László T. Department of Telecommunications and Media Informatics Budapest University of Technology and Economics Budapest Hungary Department of Automation Faculty of Engineering Sciences Széchenyi István University Gyor Hungary Faculty of Engineering Sciences Institute of Informatics Széchenyi István University Gyor Hungary

This paper considers a real-life railway timetable related problem, where a set of interconnected railway junction points form a railway network, which is essentially a directed graph with corresponding vertex and edge capacities representing railway tracks and railway *** dynamic behavior of this model is driven by a timetable. Unforeseen weather and other external effects may contribute to delays in the timetable, which alters the behavior of the whole system. In this scenario a hierarchical fuzzy system is proposed that can suggest a possible outgoing delay for each train by evaluating a set of fuzzy rule bases using two input data. The first proposal does not take into account the possible propagation of delay in the whole railway network. In this article a negative feedback is applied on the hierarchical fuzzy *** fuzzy sets are optimized by an evolution based global search metaheuristics.

关键词： Feedback

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A Probabilistic Model for Propagating Document Topic Representation in Distributed Mobile Environments

A Probabilistic Model for Propagating Document Topic Represe...

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Future Computing, Service Computation, Cognitive, Adaptive, Content, Patterns, Computation World:

作者： Zsolt Berényi István Vajk Department of Automation and Applied Informatics Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

When building document categorization in distributed mobile environments, feature selection methods need to be employed to have a compact representation for each document topic and to reduce noise during classification. When interaction occurs between the nodes, locally retrieved features representing the document topic and their attributes have to be shared to have a more accurate estimation of the global classifier at every node. The network traffic should be kept at a minimum to reduce costs. We propose a probabilistic model for a keyword selection method, which makes a more thorough analysis possible and can be considered as a basis when sharing information. It can be used for building up the local document topic representations incrementally ensuring minimal network traffic. The description of the probabilistic model is complemented by experimental results.

关键词： Distributed computing Mobile computing Information analysis Mobile communication automation informatics Environmental economics Noise reduction Peer to peer computing Telecommunication traffic

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Simple and powerful instrument model for the source separation of polyphonic music

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WSEAS Transactions on Signal Processing 2009年第1期5卷 1-10页

作者： Aczél, Kristóf Vajk, István Department of Automation and Applied Informatics Budapest University of Technology and Economics 3-9. Muegyetem rkp. H-1111 Budapest Hungary

This article presents a new approach to sound source separation. The introduced algorithm is based on spectral modeling of real instruments. The separation of independent sources is carried out by dividing the energy of the mixture signal based on these instrument models. This way it is possible to regain some of the information that was lost when the independent sources were mixed together into a single signal. The paper presents the theory behind the proposed separation system, then focuses on the instrument model that is the basic element of the approach. Measurement results are given for polyphony levels from 2 to 10 demonstrating the separation quality, with special regard to the effect of prints on the result.

关键词： Source separation

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Comparative analysis of various evolutionary and memetic algorithms

Comparative analysis of various evolutionary and memetic alg...

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10th International Symposium of Hungarian Researchers on Computational Intelligence and informatics, CINTI 2009

作者： Balázs, Krisztián Botzheim, János Kóczy, László T. Department of Telecommunications and Media Informatics Budapest University of Technology and Economics Hungary Department of Automation Széchenyi István University Gyor Hungary Faculty of Engineering Sciences Institute of Informatics Széchenyi István University Gyor Hungary

Optimization methods known from the literature include gradient techniques and evolutionary algorithms. The main idea of gradient methods is to calculate the gradient of the objective function at the actual point and then to step towards better values according to this value. Evolutionary algorithms imitate a simplified abstract model of evolution observed in nature. Memetic algorithms traditionally combine evolutionary and gradient techniques to exploit the advantages of both methods. Our current research aims to discover the properties, especially the efficiency (i.e. the speed of convergence) of particular evolutionary and memetic algorithms. For this purpose the techniques are compared by applying them on several numerical optimization benchmark functions and on fuzzy rule base identification.

关键词： Evolutionary algorithms

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