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IEEE International Conference on Intelligent Engineering Systems (INES)

作者： Czeslaw Smutnicki Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wroclaw Poland

We consider the cyclic production system providing on output the mixture of various products. Each product is produced by certain chain of operations, i. e. the unique sequence followed from the technological order. Each operations is performed on the dedicated machine. This sequence of operations is called the job. The aim is to find the cyclic schedule ensuring minimal cycle length. The problem belongs to deterministic scheduling theory, appears with the name cyclic job shop scheduling problem, is strongly NP-hard, and has been analyzed very rarely in the literature. Methodology of designing efficient optimization procedures for hard scheduling problem refers commonly to the component subproblem, namely the problem of finding cycle time or minimal cycle time for fixed job sequence. Numerical properties of this method have crucial influence on the quality of the final optimization algorithm. In this paper we propose several algorithms to solve the problem of finding cycle time for fixed job sequence. Then, we discuss and examine theoretical as well as numerical properties of these algorithms. Obtained results are illustrated by wide results of computational tests.

关键词： Schedules Job shop scheduling Optimization Convergence Algorithm design and analysis Mathematical model

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Motion planning of nonholonomic systems using highly oscillatory series

Motion planning of nonholonomic systems using highly oscilla...

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International Conference on Methods and Models in Automation and robotics (MMAR)

作者： Michal Opalka Ignacy Duleba Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wroclaw Poland

In this paper a nonholonomic motion planning task was solved using an algorithm proposed by Sussmann and Liu [8] and based on controls in the form of highly oscillatory series (HOS). Outputs of the algorithm were evaluated with respect to energy expenditure on controls and speed of its convergence. Based on characteristic features of the task, two modifications of the algorithm were proposed. Simulations were carried out on the unicycle model and an exemplary nilpotent nonholonomic system. Finally, the relevance of the algorithm to possible applications was discussed.

关键词： Trajectory Vectors Convergence Planning Frequency control Robots Optimization

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Fast model order selection of the nonlinearity in hammerstein systems

Fast model order selection of the nonlinearity in hammerstei...

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International Carpathian control Conference (ICCC)

作者： Grzegorz Mzyk Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wroclaw Poland

In the paper we show a new three-stage algorithm identifying the Hammerstein system nonlinearity. The algorithm is designed to work when a poor a priori knowledge is available and when the measurement data set is small. In the first stage, a deconvolution routine is applied to output signal in order to diminish a (usually) harmful influence of the linear dynamic component. Such filtered output is then used in a standard nonparametric estimate (be it kernel or orthogonal series one) to recover the unknown characteristics. Finally, the results of nonparametric estimation are used in the algorithm selecting the best parametric model. The entire proposed approach is illustrated by the simulation example.

关键词： Kernel Computational modeling Estimation Deconvolution Parametric statistics Noise Polynomials

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Multi-criteria optimization in control of switched systems

Multi-criteria optimization in control of switched systems

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International Carpathian control Conference (ICCC)

作者： Paweł Drąg Dominik Zelazny Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wroclaw Poland

In the paper we present a new method for solving optimal control problems of a class of hybrid systems. We describe the new effective algorithm based on memetic algorithm (MA) for optimal control of switched systems. We concentrate on a class of problems in which a pre-specified sequence of active subsystems is known. Our aim is to find both the optimal switching instants and the optimal continuous inputs. The new approach, which we propose, decomposes the cost functional of the basic optimal control problem in Bolza form in two terms. The first term depends explicitly on a value of state variables at the final time. The second term depends on state and control trajectories. In order to solve those two tasks we used MA as the multi-objective optimization algorithm. In this paper we considered a fundamental bi-criteria case with two mentioned before functions: the value of state variables at the final time and the state and control trajectories. In order to find an approximation of Pareto frontier, we proposed new effective method based on genetic algorithm (GA) and local search (LS). Problems properties were taken into consideration in the design of our new approach of solving it. They were used to construct new algorithm inspired by the LS NSGA-II, which performed rather well in multi-criteria scheduling problem. Since simple genetic algorithms are efficient heuristics in searching for optimal solutions, but lack the accuracy of some more computational complex algorithms, a hybrid algorithm was constructed. It uses fast non-dominated sorting, in order to evaluate child population and allocate solutions to corresponding Pareto frontiers. I addition a local search method was used, in order to find more differentiated and better solutions. Clustering solutions from Pareto frontiers also improved diversity of solutions in child population. This approach can be used as a start point for searching for algorithm for solving optimal control problems of switched systems wit

关键词： Optimal control Switches Switched systems Genetic algorithms Trajectory Algorithm design and analysis

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Identity of a companion, migrating between robots significantly different in terms of expressive capabilities: Initial results of VHRI study

Identity of a companion, migrating between robots significan...

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International Conference on Methods and Models in Automation and robotics (MMAR)

作者： Krzysztof Arent Bogdan Kreczmer Łukasz Małek Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wroclaw Poland

In this paper we deal with a companion that is capable of migration to variety of embodiments in order to fulfil its tasks (including the social one) and to achieve its goals. It is important that identity of a companion in each utilised embodiment can be recognised by the user regardless technological constraints and own capabilities of a robotic platform. We are focused on the case when one companion uses two robots, embodied in different degrees, whereby one robot is poorly embodied. In this context the concept of unfalsified identity is introduced. In video-based user studies the less embodied robot companion reveals a certain set of characteristic behaviours relevant the context and the currently carried out task. These behaviours are consistent with behaviours observed by the user earlier, in similar contexts, when the companion was more embodied. It follows from the study that the user can properly recognise the identity of this companion with a certain level of confidence. A number of observations relevant to behaviours as identity cues are presented and discussed.

关键词： Context Robot sensing systems Mobile communication Educational institutions computers Electronic mail

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An impact of model parameter uncertainty on scheduling algorithms

An impact of model parameter uncertainty on scheduling algor...

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14th International Conference on Enterprise Information Systems, ICEIS 2012

作者： Rudek, Radoslaw Rudek, Agnieszka Kozik, Andrzej Skworcow, Piotr Institute of Business Informatics Wroclaw University of Economics Wroclaw Poland Department of Systems and Computer Networks Wroclaw University of Technology Wroclaw Poland Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wroclaw Poland De Montfort University Water Software Systems Leicester United Kingdom

ISBN: (纸本)9789898565105

This short paper presents a preliminary analysis of the impact of model parameter uncertainty on the accuracy of solution algorithms for the scheduling problems with the learning effect. We consider the maximum completion time minimization flowshop problem with job processing times described by the power functions dependent on the number of processed jobs. To solve the considered scheduling problem we propose heuristic (NEH based) and metaheuristic (simulated annealing) algorithms. The numerical experiments show that NEH and simulated annealing are robust for this problem with respect to model parameter uncertainty.

关键词： Simulated annealing

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Practical Dynamic Thermal Management of multi-core microprocessors

Practical Dynamic Thermal Management of multi-core microproc...

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International Workshop on Thermal Investigation of ICs and Systems (THERMINIC)

作者： Bartosz Wojciechowski Marek A. Bawiec Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wrocław Poland

Here we present an implementation of thermally-aware DVFS governor in a form of Linux 3.2 module. Our thermal governor operates by reading digital thermal sensors placed in CPU cores and pro-actively adjusting operating frequency of individual cores to maintain temperatures below given threshold. We evaluate our method using state-of-the-art parallel benchmarks from PARSEC suite. Apart from evaluation of our thermally-aware DVFS governor, we present insights into operation of a modern high-performance CPU with 6 cores and 2 hardware threads per core.

关键词： Temperature measurement Temperature sensors Temperature Thermal management computers Linux

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Temperature prediction for multi-core microprocessors with application to Dynamic Thermal Management

Temperature prediction for multi-core microprocessors with a...

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International Workshop on Thermal Investigation of ICs and Systems (THERMINIC)

作者： Bartosz Wojciechowski Janusz Biernat Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wrocław Poland

Temperature is among the most important factors limiting CPU performance. To ensure stable and reliable operation temperature has to be limited. In this paper we present a method for predicting temperature of a multi-core microprocessor based on it's high-level thermal model. Temperature prediction is then utilised in a Dynamic Thermal Management algorithm that can exploit performance optimisation opportunities while ensuring operation below temperature limit. The DTM algorithm uses frequency and voltage scaling of the CPU cores and task migration and was evaluated on a physical computer with a quad-core CPU.

关键词： Temperature measurement Heuristic algorithms Prediction algorithms Computational modeling Multicore processing Microprocessors computers

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Parallel Simultaneous Approach for optimal control of DAE systems

Parallel Simultaneous Approach for optimal control of DAE sy...

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Federated Conference on computer Science and Information Systems (FedCSIS)

作者： Paweł Drąg Krystyn Styczeń Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wrocław Poland

In the paper two approaches of parallelization for solving optimal control problems of ODE and index-1 DAE systems were presented and discussed. DAE Optimization Problem can be treated by Direct Nonlinear Programming Approach in two manners, known as Sequential Approach and Simultaneous Approach. Simultaneous Approach seems to be more reliable, because provides initial states in periods and discretized control variables. Therefore there is a possibility of efficient use of Optimization with multiple shooting, which was developed to handle unstable DAE systems. In the article some parallelization methods of the Sequential Quadratic Programming were discussed and compared both in the Jacobian calculation and the numerical integration of DAE models. Augmented objective function, based on Mathematical Programming with Complementarity Constraints, was proposed. The illustrative simulations of Catalyst Mixing Problem were performed in MATLAB, which is a commonly known programming environment.

关键词： Linear programming Mathematical model Optimization Optimal control Parallel processing Equations Computational modeling

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Implementing AES and serpent ciphers in new generation of low-cost FPGA devices

Advances in Intelligent and Soft Computing

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Advances in Intelligent and Soft Computing 2012年 170 AISC卷 273-287页

作者： Sugier, Jaroslaw Institute of Computer Engineering Control and Robotics Wroclaw University of Technology ul. Janiszewskiego 11/17 50-372 Wroclaw Poland

ISBN: (纸本)9783642306617

New generations of FPGA devices that are being continuously developed provide the designers with extended capabilities and create new options for implementation of contemporary ciphers. This work presents implementations of the two best algorithms of the AES contest-Rijndael and Serpent-in Spartan-6 devices from Xilinx and compares them with equivalent effects that were obtained in architectures of the previous generation. The included results allow for evaluation of implementation cost vs. efficiency in contemporary FPGA chips for these two cryptographic algorithms and also provide some conclusions about how the situation changes with development of new, more powerful programmable architectures. © 2012 Springer-Verlag Berlin Heidelberg.

关键词： Field programmable gate arrays (FPGA)

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