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1
Content available Model for dynamic and hierarchical data repository in relational database
Piech M., Fracz W., Turek W., Kisiel-Dorohinicki M., Dajda J., Byrski A.
Computer Science
|
2018
|
Vol. 19 (4)
479--500
EN
The aim of this research is to build an open schema model for a digital sources repository in a relational database. This required us to develop a few advanced techniques. One of them was to keep and maintain a hierarchical data structure pushed into the repository. A second was to create constraints on any hierarchical level that allows for the enforcement of data integrity and consistency. The created solution is mainly based on a JSON file as a native column type, which was designed for holding open schema documents. In this paper, we present a model for any repository that uses hierarchical dynamic data. Additionally, we include a structure for normalizing the input and description for the data in order to keep all of the model assumptions. We compared our solution with a well-known open schema model – Entity-Attribute-Value – in the scope of saving data and querying about relationships and contents from the structure. The results show that we achieved improvements in both the performance and disk space usage, as we extended our model with a few new features that the previous model does not include. The techniques developed in this research can be applied in every domain where hierarchical dynamic data is required, as demonstrated by the digital book repository that we have presented.
2
Content available Emergence of population structure in socio-cognitively inspired ant colony optimization
Byrski A., Świderska E., Łasisz J., Kisiel-Dorohinicki M., Lenaerts T., Samson D., Indurkhya B.
Computer Science
|
2018
|
Vol. 19 (1)
81--98
EN
A metaheuristic proposed by us recently, Ant Colony Optimization (ACO) hybridized with socio-cognitive inspirations, turned out to generate interesting results compared to classic ACO. Even though it does not always find better solutions to the considered problems, it usually finds sub-optimal solutions usually. Moreover, instead of a trial-and-error approach to configure the parameters of the ant species in the population, in our approach, the actual structure of the population emerges from predefined species-to-species ant migration strategies. Experimental results of our approach are compared against classic ACO and selected socio-cognitive versions of this algorithm.
3
Content available Analysis of distributed systems dynamics with Erlang Performance Lab
Ślaski M., Turek W., Gil A., Szafran B., Paciorek M., Byrski A.
Computer Science
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2018
|
Vol. 19 (2)
139--155
EN
Modern, highly concurrent, and large-scale systems require new methods for design, testing, and monitoring. Their dynamics and scale require real-time tools that provide a holistic view of the whole system and the ability to show a more detailed view when needed. Such tools can help identify the causes of unwanted states, which is hardly possible with a static analysis or metrics-based approach. In this paper, a new tool for the analysis of distributed systems in Erlang is presented. It provides the real-time monitoring of system dynamics on diferent levels of abstraction. The tool has been used for analyzing a large-scale urban trafic simulation system running on a cluster of 20 computing nodes.
4
Content available Mobile Cloud for Parallel and Distributed Green Computing
Siwik L., Kala D., Godzik M., Turek W., Byrski A., Kisiel-Dorohinicki M.
Journal of Telecommunications and Information Technology
|
2017
|
nr 4
60--70
EN
Mobile Computing and Mobile Cloud Computing are the areas where intensive research is observed. The “mobility” landscape (devices, technologies, apps, etc.) evolves so fast that definitions and taxonomies do not catch up with so dynamic changes and there is still an ambiguity in definitions and common understanding of basic ideas and models. This research focuses on Mobile Cloud understood as parallel and distributed system consisting of a collection of interconnected (and virtualized) mobile devices dynamically provisioned and presented as one unified computing resource. This paper focuses on the mobile green computing cloud applied for parallel and distributed computations and consisting of outdated, abandoned or no longer needed smartphones being able to set up a powerful computing cluster. Besides showing the general idea and background, an actual computing cluster is constructed and its scalability and efficiency is checked versus the results obtained from the virtualized set of smartphones. All the experiments are performed using a dedicated software framework constructed in order to leverage the nolonger-needed smartphones, creating a computing cloud.
5
Content available Collectively intelligent prediction in evolutionary multi-agent system
Kijak J., Martyna P., Byrski A., Faber Ł., Piętak K., Kisiel-Dorohinicki M.
International Journal of Microelectronics and Computer Science
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2017
|
Vol. 8, nr 3
85--96
EN
In the paper a summary of our previously realized and published work connected with constructing collective intelligent evolutionary multi-agent systems for time series prediction, based on multi-layered perceptrons is shown. Besides recalling our past papers, we describe the whole concept, present an implementation in a contemporary, componentoriented software framework AgE 3.0 and we conduct a number of experiments, finding different optimal parametrization for the considered instances of the problems (popular Mackey-Glass chaotic time series). The paper may be useful for a practitioner willing to use our meatheuristic algorithm (EMAS) along with the idea of collective agent-based system in order to realize prediction tasks.
6
Content available remote Volunteer computing in a scalable lightweight web-based environment
Chorazyk P., Byrski A., Pietak K., Kisiel-Dorohinicki M., Turek W.
Computer Assisted Methods in Engineering and Science
|
2017
|
Vol. 24, no. 1
17--40
EN
Volunteer computing is a very appealing way of utilizing vast available resources in efficient way. However, the current platforms that support such computing style are either difficult to use or not available at all, as a results of finished scientific projects, for example. In this paper, a novel lightweight volunteer computing platform is presented and thoroughly tested in an artificial environment of a commercially available computing cloud using two computing-related tasks and one web-crawling-related task.
7
Koordynacja ruchu robotów mobilnych algorytmem inspirowanym zjawiskami społecznymi
Szomiński S., Cieśla Ł., Turek W., Byrski A.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2016
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z. 195, t. 1
25--36
PL
Zarówno zwierzęta jak i ludzie, są w stanie autonomicznie rozwiązać problem wyzmaczania trajektorii, podczas przemieszczania się we wspólnej, ograniczonej przestrzeni. Realizują to bez centralnego planowanie, oraz bez jawnej komunikacji. Obserwacje te skłoniły autorów do stworzenia zdecentralizowanego algorytmu koordynacji robotów mobilnych, rozwiązującego problem wąskich przejść, oraz wyznaczenia pierwszeństwa w drzwiach. W prezentowanej metodzie wykorzystano inspiracje naturalnymi zjawiskami, .jak respekt do osobników większych, czy stojących wyżej w hierarchii społecznej. Prezentowana metoda, została przetestowana w symulatorze, oraz na rzeczywistych robotach mobilnych, oraz została porównana z uznaną metodą Reciprocal Vetocity Obstacles.
EN
Animals or humans are able to plan trajectories for individuals autonomously, without explicit communication. These observations led the authors to create a decentralized algorithm for coordination of mobile robots motion solving the problem of narrow passages and determine the priori ty in the door. The presented method models instincts such as respect for bigger individuals and groups. The presented method has been tested in simulation and with real mobile robots, and was compared with a well-recognized Reciprocal Velocity Obstacles method.
8
Content available Parallel patterns for agent-based evolutionary computing
Stypka J., Anielski P., Mentel S., Krzywicki D., Turek W., Byrski A., Kisiel-Dorohinicki M.
Computer Science
|
2016
|
Vol. 17 (1)
83--98
EN
Computing applications such as metaheuristics-based optimization can greatly benefit from multi-core architectures available on modern supercomputers. In this paper, we describe an easy and efficient way to implement certain population-based algorithms (in the discussed case, multi-agent computing system) on such runtime environments. Our solution is based on an Erlang software library which implements dedicated parallel patterns. We provide technological details on our approach and discuss experimental results.
9
Content available Agent-based optimization of advisory strategy parameters
Polnik M., Kumięga M., Byrski A.
Journal of Telecommunications and Information Technology
|
2013
|
nr 2
49--55
EN
In this paper, an application of Evolutionary Multiagent Systems (EMAS) and its memetic version to the optimization of advisory strategy (in this case, Sudoku advisory strategy) is considered. The problem is tackled using an EMAS, which has already proven as a versatile optimization technique. Results obtained using EMAS and Parallel Evolutionary Algorithm (PEA) are compared. After giving an insight to the possibilities of decision support in Sudoku solving, an exemplary strategy is defined. Then EMAS and its memetic versions are discussed, and experimental results concerning comparison of EMAS and PEA presented.
10
Content available Volunteer computing simulation using repast and mason
Byrski A., Feluś M., Gawlik J., Jasica R., Kobak P., Jankowski G., Nawarecki E., Wroczyński M., Majewski P, Krupa T., Strychalski J.
Computer Science
|
2013
|
Vol. 14 (1)
153--172
EN
Volunteer environments usually consist of a large number of computing nodes, with highly dynamic characteristics, therefore reliable models for a planning of the whole computing are highly desired. An easy to implement approach to modelling and simulation of such environments May employ agent-based universal simulation frameworks, such as RePast or MASON. In the course of the paper the above-mentioned simulation frame Works are adapter to suport simulation of volunteer computing. After giving implementation details, selected results concerning computing time and speedup are given and are compared with the ones obtained from an actual volunteer environment.
11
Content available Tuning of agent-based computing
Byrski A.
Computer Science
|
2013
|
Vol. 14 (3)
491--512
EN
In this paper, an Evolutionary Multi-agent system-based computing process is subjected to a detailed analysis of its parameters in order to establish a base for a better understanding of the meta-heuristics from the practitioner’s point of view. After reviewing the concepts of EMAS and its immunological variant, a series of experiments is shown, and results of the influence of the search outcomes by certain parameters is discussed.
12
Content available Evolutionary multi-agent computing in inverse problems
Wróbel K., Torba P., Paszyński M, Byrski A.
Computer Science
|
2013
|
Vol. 14 (3)
367--383
EN
This paper tackles the application of evolutionary multi-agent computing to solve inverse problems. High costs of fitness function call become a major difficulty when approaching these problems with population-based heuristics. However, evolutionary agent-based systems (EMAS) turn out to reduce the fitness function calls, which makes them a possible weapon of choice against them. This paper recalls the basics of EMAS and describes the considered problem (Step and Flash Imprint Lithography), and later, shows convincing results that EMAS is more effective than a classical evolutionary algorithm.
13
Content available Analiza dynamiki układu tłokowo-korbowego wybranego silnika spalinowego przy użyciu interfejsu programów MSC.ADAMS i ANSYS
Harlecki A., Urbaś A., Nowakowski J., Byrski A.
Combustion Engines
|
2013
|
R. 52, nr 3
1076--1083
PL
W pracy przedstawiono metodę analizy wytrzymałościowej członów układu tłokowo-korbowego wybranego silnika spalinowego o zapłonie samoczynnym, stanowiącego przykład układu mechanicznego o szybkozmiennej dynamice. W analizie dynamiki układu, zrealizowanej w środowisku programów MSC.ADAMS i ANSYS, uwzględniono podatność wszystkich jego podstawowych członów, tzn. tłoka wraz ze sworzniem tłokowym, korbowodu i wału korbowego. Finalną część analizy stanowiły obliczenia wytrzymałościowe wymienionych członów. Zdaniem autorów, prezentowana metoda może być użyteczna w nowocześnie pojmowanym procesie projektowania silników spalinowych.
EN
The paper presents a method of stress analysis of components of the piston-crank system of a selected internal combustion engine as an example of the mechanical system with quick-changing dynamics. In the analysis of the dynamics of the system, carried out in the MSC.ADAMS and ANSYS software environment, the flexibility of all the major members of the system, i.e. piston with piston pin, connecting rod, and crankshaft, was taken into account. The final part of the analysis includes calculations of strength of the aforementioned system members. In authors’ opinion, the method presented may be useful in the up-to-date process of designing internal combustion engines.
14
Content available Asymptotic guarantee of success for multi-agent memetic systems
Byrski A., Schaefer R., Smołka M., Cotta C.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2013
|
Vol. 61, nr 1
257-278
EN
The paper introduces a stochastic model for a class of population-based global optimization meta-heuristics, that generalizes existing models in the following ways. First of all, an individual becomes an active software agent characterized by the constant genotype and the meme that may change during the optimization process. Second, the model embraces the asynchronous processing of agent’s actions. Third, we consider a vast variety of possible actions that include the conventional mixing operations (e.g. mutation, cloning, crossover) as well as migrations among demes and local optimization methods. Despite the fact that the model fits many popular algorithms and strategies (e.g. genetic algorithms with tournament selection) it is mainly devoted to study memetic algorithms. The model is composed of two parts: EMAS architecture (data structures and management strategies) allowing to define the space of states and the framework for stochastic agent actions and the stationary Markov chain described in terms of this architecture. The probability transition function has been obtained and the Markov kernels for sample actions have been computed. The obtained theoretical results are helpful for studying metaheuristics conforming to the EMAS architecture. The designed synchronization allows the safe, coarse-grained parallel implementation and its effective, sub-optimal scheduling in a distributed computer environment. The proved strong ergodicity of the finite state Markov chain results in the asymptotic stochastic guarantee of success, which in turn imposes the liveness of a studied metaheuristic. The Markov chain delivers the sampling measure at an arbitrary step of computations, which allows further asymptotic studies, e.g. on various kinds of the stochastic convergence.
15
Content available Towards an Agent-Based Augmented Cloud
Dębski R., Byrski A., Kisiel-Dorohinicki M.
Journal of Telecommunications and Information Technology
|
2012
|
nr 1
16-22
EN
In the paper an agent-based framework deployed in hybrid cluster and volunteer computing environment is presented. It utilizes two concepts proposed by the authors: Augmented Cloud and Agent Platform as a Service (AgPaaS). Both concepts are discussed in the context of Cloud Computing as defined by NIST. The key idea of the presented solution is to span the cloud (i.e., computing infrastructure) beyond the data center borders by utilizing web browsers as computational workers. The feasibility of the approach was demonstrated by two prototypes: the first one was based on Java Applets and Adobe Flash, whereas the second one on Microsoft Silverlight. The prototypes were next used to perform simple experiments, mainly related to scalability issues. Selected results from the experiments are discussed in the final part of the paper.
16
Content available Component-Based Architecture for Systems, Services and Data Integration in Support for Criminal Analysis
Dajda J., Dębski R., Byrski A., Kisiel-Dorohinicki M.
Journal of Telecommunications and Information Technology
|
2012
|
nr 1
67-73
EN
Criminal analysis processes is based on heterogeneous data processing. To support it, analysts utilize a large set of specialized tools, however they are usually designed to solve a particular problem are often incompatible with other existing tools and systems. Therefore, to fully leverage the existing supporting tools, their technological integration is required. In this paper we present original approach for integrating systems based on the component-driven paradigm. Firstly, a problem of supporting criminal analysis is described with a strong emphasis on the heterogeneity issues. Secondly, some theoretical information about integration is depicted followed by the details of the proposed architecture. Finally, the technological assumptions are discussed and prototype integration based on proposed concept is overviewed. om the experiments are discussed in the final part of the paper.
17
Content available The island model as a Markov dynamic system
Schaefer R., Byrski A., Smołka M.
International Journal of Applied Mathematics and Computer Science
|
2012
|
Vol. 22, no. 4
971-984
EN
Parallel multi-deme genetic algorithms are especially advantageous because they allow reducing the time of computations and can perform a much broader search than single-population ones. However, their formal analysis does not seem to have been studied exhaustively enough. In this paper we propose a mathematical framework describing a wide class of island-like strategies as a stationary Markov chain. Our approach uses extensively the modeling principles introduced by Vose, Rudolph and their collaborators. An original and crucial feature of the framework we propose is the mechanism of inter-deme agent operation synchronization. It is important from both a practical and a theoretical point of view. We show that under a mild assumption the resulting Markov chain is ergodic and the sequence of the related sampling measures converges to some invariant measure. The asymptotic guarantee of success is also obtained as a simple issue of ergodicity. Moreover, if the cardinality of each island population grows to infinity, then the sequence of the limit invariant measures contains a weakly convergent subsequence. The formal description of the island model obtained for the case of solving a single-objective problem can also be extended to the multi-objective case.
18
Content available Hybrid neuro-fuzzy classifier based on NEFCLASS model
Gliwa B., Byrski A.
Computer Science
|
2011
|
Vol. 12
115-135
EN
The paper presents hybrid neuro-fuzzy classifier, based on NEFCLASS model, which was modified. The presented classifier was compared to popular classifiers - neural networks and k-nearest neighbours. Efficiency of modifications in classifier was compared with methods used in original model NEFCLASS (learning methods). Accuracy of classifier was tested using 3 datasets from UCI Machine Learning Repository: iris, wine and breast cancer wis-consin. Moreover, influence of ensemble classification methods on classification accuracy was presented.
PL
Artykuł przedstawia zasadę działania oraz wyniki badań eksperymentalnych klasyfikatora opartego na hybrydzie sieci neuronowej z logiką rozmytą, bazujący na modelu NEFCLASS. Prezentacja struktury i działania klasyfikatora została zilustrowana wynikami eksperymentów porównawczych przeprowadzonych dla popularnych klasyfikatorów, takich jak perceptron wielowarstwowy k najbliższych sąsiadów. Skuteczność wprowadzonych modyfikacji do klasyfikatora została porównana z metodami używanymi w oryginalnym modelu NEFCLASS (metody uczenia). Jako dane benchmarkowe posłużyły wybrane bazy danych z UCI Machine Learning Repository (iris, wine, breast cancer wisconsin). Zaprezentowano również wpływ użycia metod klasyfikacji zbiorczej na efektywność klasyfikacji.
19
Content available A crisis management approach to mission survivability in computational multi-agent systems
Byrski A., Kisiel-Dorohinicki M., Carvalho M.
Computer Science
|
2010
|
Vol. 11
99-113
EN
In this paper we present a biologically-inspired approach for mission survivability (considered as the capability of fulfilling a task such as computation) that allows the system to be aware of the possible threats or crises that may arise. This approach uses the notion of resources used by living organisms to control their populations. We present the concept of energetic selection in agent-based evolutionary systems as well as the means to manipulate the configuration of the computation according to the crises or user's specific demands.
PL
W artykule prezentujemy biologicznie inspirowany mechanizm wspomagający utrzymanie krytycznych zadań (tzw. mission survivability) który umożliwia wykrywanie oraz przeciwdziałanie wybranym zagrożeniom. Przedstawione podejście wzorowane jest na wykorzystywaniu przez żywe organizmy zasobów do kontroli populacji. Prezentujemy koncepcje selekcji energetycznej mającej zastosowanie w ewolucyjnych systemach wieloagentowych (EMAS) oraz sposoby konfiguracji obliczenia w celu przeciwdziałania sytuacjom kryzysowym, według preferencji użytkownika.
20
Stochastic Dynamics of Evolutionary Multi-Agent Systems
Byrski A., Schaefer R.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2009
|
z. 169
27-34
EN
The refined model for the biologically inspired agent-based computation system EMAS conformed to BDI standard is presented. The considerations are based on the model of the system dynamics as the stationary Markov chain already presented. In the course of paper space of the system states is modified in order assure state coherency and set of actions is simplified. Such a model allows for better understanding the behavior of the proposed complex systems as well as their limitations.
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