Wyniki wyszukiwania - Biblioteka Nauki

1

LDYIS: a Framework for Model Checking Security Protocols

100%

Lomuscio A. , Penczek W.

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2008

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tom Vol. 85, nr 1-4

359-375

EN

We present a formalism for the automatic verification of security protocols based on multi-agent systems semantics. We give the syntax and semantics of a temporal-epistemic security-specialised logic and provide a lazy-intruder model for the protocol rules that we argue to be particularly suitable for verification purposes. We exemplify the technique by finding a (known) bug in the traditional NSPK protocol.

2

Cooperative World Modeling in Dynamic Multi-Robot Environments

63%

Göhring D. , Burkhard H.-D.

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2007

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tom Vol. 75, nr 1-4

281-294

EN

In this paper we describe how a group of agents can commonly estimate the position of objects. Furthermore we will show how these modeled object positions can be used for an improved self localization. Modeling of moving objects is commonly done by a single agent and in a robo-centric coordinate frame because this information is sufficient for most low level robot control and it is independent of the quality of the current robot localization. Especially when many robots cooperate with each other in a partially observable environment they have to share and to communicate information. For multiple robots to cooperate and share information, though, they need to agree on a global, allocentric frame of reference. But when transforming the egocentric object model into a global one, it inherits the localization error of the robot in addition to the error associated with the egocentric model. We propose using the relation of objects detected in camera images to other objects in the same camera image as a basis for estimating the position of the object in a global coordinate system. The spacial relation of objects with respect to stationary objects (e.g., landmarks) offers several advantages: The information is independent of robot localization and odometry and it can easily be communicated. We present experimental evidence that shows how two robots are able to infer the position of an object within a global frame of reference, even though they are not localized themselves. We will also show, how to use this object information for self localization. A third aspect of this work will cope with the communication delay, therefore we will show how the Hidden Markov Model can be extended for distributed object tracking.

3

A Formal Model of Multi-Agent Organisations

63%

Köhler M.

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2007

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tom Vol. 79, nr 3-4

415-430

EN

Agent oriented software engineering is seen as the approach taking object oriented approaches one step ahead. The design of agent systems is based on three fundamental perspectives: the functional, the team-interactional and the organisational perspective. The organisational perspective becomes a central design issue if the number of agents is large or the environment is unstable. While the functional perspective is well founded in the planning theory of artificial intelligence and the interactional perspective is rooted in the theory of speech-acts and formal ontologies, the organisational perspective is still an active research area with several open questions. In this paper we define a formal organisation model for agent systems based on Petri nets and show how agent oriented software engineering can benefit from this model.

4

Towards SAT-based BMC for LTLK over Interleaved Interpreted Systems

63%

Penczek W. , Woźna-Szcześniak B. , Zbrzezny A.

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2012

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tom Vol. 119, nr 3/4

373-392

EN

This paper makes two contributions to the verification of multi-agent systems modelled by interleaved interpreted systems. Firstly, the paper presents theoretical underpinnings of the SATbased bounded model checking (BMC) approach for LTL extended with the epistemic component (LTLK) over interleaved interpreted systems. Secondly, the BMC method has been implemented and tested on several benchmarks for MAS. The preliminary experimental results reveal advantages and disadvantages of our SAT-based BMC for LTLK and show that the method has a significant potential.

5

Problem integralności funkcjonalnej pewnej klasy systemów wieloagentowych

63%

Cetnarowicz K.

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1999

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tom Vol. 1

15-41

PL

Systemy wieloagentowe posiadają szereg zalet i otwierają wiele nowych możliwości w tworzeniu systemów informatycznych, jednak wiele problemów związanych z działaniem tych systemów pozostaje do rozwiązania. Do takich problemów należy integralność funkcjonalna systemów wieloagentowych. Integralność funkcjonalną systemu wieloagentowego można zdefiniować, najogólniej mówiąc, jako zachowanie podstawowych funkcji systemu w czasie jego funkcjonowania. Można ją analizować z punktu widzenia różnych funkcji systemu (które powinny pozostać zachowane) jak i z punktu widzenia różnych czynników jakie mogą wpływać na utratę lub zachowanie integralności funkcjonalnej przez system. W pracy zajęto się badaniem integralności funkcjonalnej systemu wieloagentowego w zależności od ilości agentów (globalną i poszczególnych typów). Agenci w czasie pracy systemu generują agentów tego samego lub innego typu, w zależności od swoich możliwości i potrzeb systemu. Proces ten realizowany bez odpowiednich mechanizmów kontrolnych może doprowadzić do nadmiernej liczby agentów (zablokowanie systemu) lub zbyt małej, aż do zupełnego braku agentów danego typu (zanik funkcji systemu realizowanej przez agentów danego typu). W pracy przedstawiono propozycję analizy zjawiska integralności funkcjonalnej systemów wieloagentowych, związanego z licznością populacji agentów i propozycję mechanizmów umożliwiających utrzymanie integralności funkcjonalnej, w szczególności koncepcję tzw. "wolnych agentów". Rozważania przeprowadzono w oparciu o badanie symulacyjne pewnej klasy systemów wieloagentowych, a wyniki symulacyjnych badań proponowanych rozwiązań zamieszczono w niniejszej pracy.

EN

Multi-agent systems have many advantages and give numerous new possibilities in creation of information systems. However many problems related to functioning of the systems are still unsolved. Functional integrity of multi-agent systems belongs to such problems. Functional integrity of multi-agent systems may be defined in general as preservation of basic functions of the system during its functioning. Functional integrity may be analyzed from the point of view of different functions of the system (the functions that should be preserved) and also from the point of view of various factors that may influence the loss or preservation of functional integrity of the system. The paper deals with examination of functional integrity of multi-agent system depending upon number of agents (global and of particular types). During system work, agents generate agents of the same or different type that depend on their possibilities and system needs. The process performed without use of appropriate control mechanisms may lead to excessive (blocking of the system) or too little number of agents and even lack of agents (disappearance of the functions of a system that are performed by a gents of a certain type). A proposal of functional integrity phenomenon analysis of multi-agent systems that is related to the number of agents in their population and a proposal of mechanisms that enable maintenance of functional integrity, in particular a concept of the so-call ed "free agents" have been presented in the paper. Consideration has been carried out on the basis of simulation examination of some elass of multi-agent systems. Results of simulation of proposed Solutions have been included in the work.

6

Architecture for Discovery of Crises in MAS

63%

Nawarecki E. , Kisiel-Dorohinicki M. , Dobrowolski G.

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2006

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tom Vol. 71, nr 1

37-47

EN

The contribution deals with a class of intelligent decentralized systems that meet the agent paradigm. Such systems are marked by the possibility of arising critical situations, interpreted here as the threat of loss (partial or complete) of the system functionality. The work is focused on designing an overall architecture of the (sub-)system dedicated to the discovery of crises and support of anti-crisis activities. The architecture is proposed as a reference one so as it is possible to adjust it to the specificity of any particular application. As an illustration the case of a transportation system is discussed.

7

Supporting Action-at-a-distance in Situated Cellular Agents

51%

Bandini S. , Mauri G. , Vizzari G.

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2006

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tom Vol. 69, nr 3

251-271

EN

The aim of this paper is to describe algorithms and structures required to support action-at-a-distance in Situated Cellular Agents (SCA). This model provides the possibility to define heterogeneous entities placed in regular or irregular spatial infrastructures. Different mechanisms supporting field diffusion within these structures will be described and analyzed, with reference to their performance. A sample application of SCA model (a variation of Conway's Game of Life) will also be illustrated, while a more complex usage of action-at-a-distance for pedestrian simulation will be sketched.

8

Ewolucyjne systemy wieloagentowe dla optymalizacji wielokryterialnej

51%

Kisiel-Dorohinicki M. , Dobrowolski G. , Nawarecki E.

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2001

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tom T. 5, z. 1/2

319-327

PL

W pracy zaproponowano nowe podejście do problemu poszukiwania globalnego rozwiązania zadania optymalizacji wielokryterialnej w sensie Pareto. Podejście opiera się na koncepcji ewolucyjnego systemu wieloagentowego, stanowiącej rozszerzenie klasycznego algorytmu ewolucyjnego. Decentralizacja procesu ewolucji i inne zjawiska właściwe systemom agentowym pozwalają na intensywniejsze przeszukiwanie przestrzeni rozwiązań i jednocześnie efektywną aproksymację frontu Pareto. Przedstawiono opis zastosowanej techniki rozwiązywania oraz wyniki podstawowych eksperymentów.

EN

This work introduces a new evolutionary approach to searching for a global solution in the Pareto sense to multiobjective optimisation problem. Novelty of the proposed method consists in application of an evolutionary multi-agent system (EMAS) instead of clasical evolutionary algorithms. Decentralisation of the evolution process in EMAS allows for intensive exploration of the search space and effective approximation of the whole Pareto frontier. In the paper a description of the technique is presented as well as preliminary experimental results are reported.

9

Model Checking Temporal-Epistemic Logic Using Alternating Tree Automata

51%

Belardinelli F. , Jones A. V. , Lomuscio A.

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2011

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tom Vol. 112, nr 1

19-37

EN

We introduce a novel automata-theoretic approach for the verification of multi-agent systems. We present epistemic alternating tree automata, an extension of alternating tree automata, and use them to represent specifications in the temporal-epistemic logic CTLK. We show that model checking a memory-less interpreted system against a CTLK property can be reduced to checking the language non-emptiness of the composition of two epistemic tree automata. We report on an experimental implementation and discuss preliminary results. We evaluate the effectiveness of the technique using two real-life scenarios: a gossip protocol and the train gate controller.

10

Metoda wieloagentowa - wizualizacja działania na przykładzie systemu sterowania produkcją

51%

Góralski J.

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2010

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tom T. 19

79-85

PL

Tematyką referatu jest system sterowania produkcją działający w oparciu o zasady sztucznej inteligencji. Działanie systemu zostało zwizualizowane w programie klasy SCADA. Przedmiotem referatu jest metoda wieloagentowa, której zasady zostały zaimplementowane w algorytmach wykonawczych sterujących Miniaturowym Elastycznym Systemem Sterowania (MESW). W pierwszej części przedstawiono idee sterowania wieloagentowego oraz scharakteryzowano środowisko pracy. W drugiej części scharakteryzowano narzędzie przeznaczone do sterowania i wizualizacji przebiegu procesu produkcyjnego - Wonderware InTouch. Ostatnim etapem jest prezentacja wizualizacji pracujących obiektów, których działanie znalazło zastosowanie podczas sterowania MESW, znajdującym się w Zachodniopomorskim Uniwersytecie Technologicznym w Szczecinie.

EN

The major thesis of this paper is controlling of the production based on artificial intelligence. System operation is visualized in program class SCADA. Main object is multi-agent system, which is implemented in executive algorithms controlling of Miniature Flexible Production System - MESW. In the first part of the paper presents multi-agent controlling ideas and characterizes its working environment. Second part is showing executive algorithms together with controlling and visualization tools necessary to production process - Wonerware InTouch. The last section contains movie, which shows projected objects used in production controlling in MESW, placed in The West Pomeranian University of Technology in Szczecin.

11

Stochastic Model of Evolutionary and Immunological Multi-Agent Systems: Mutually Exclusive Actions

51%

Byrski A. , Schaefer R.

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2009

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tom Vol. 95, nr 2/3

263-285

EN

The mathematical model of the biologically inspired, memetic, agent-based computation systems EMAS and iEMAS conformed to BDI standard is presented. The state of the systems and their dynamics are expressed as stationary Markov chains. Such an approach allows to better understand their complex behavior as well as their limitations.

12

Stochastic Model of Evolutionary and Immunological Multi-Agent Systems: Parallel Execution of Local Actions

51%

Schaefer R. , Byrski A. , Smołka M.

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2009

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tom Vol. 95, nr 2/3

325-348

EN

The refined model for the biologically inspired agent-based computation systems EMAS and iEMAS conforming to the BDI standard is presented. Moreover, their evolution is expressed in the form of the stationary Markov chains. This paper generalizes the results obtained by Byrski and Schaefer [7] to a strongly desired case in which some agents’ actions can be executed in parallel. In order to find the Markov transition rule, the precise synchronization scheme was introduced, which allows to establish the stepwise stochastic evolution of the system. The crucial feature which allows to compute the probability transition function in case of parallel execution of local actions is the commutativity of their transition operators. Some abstract conditions expressing such a commutativity which allow to classify the agents’ actions as local or global are formulated and verified in a very simple way. The above-mentioned Markov model constitutes the basis of the asymptotic analysis of EMAS and iEMAS necessary to evaluate their search possibilities and efficiency.

13

An experimental investigation of the synergetic effect of multiple agents working together in the A-Team

51%

Barbucha D. , Jędrzejowicz P.

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2008

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tom Vol. 34, no 2

55-62

EN

The paper aims at evaluating experimentally the existence and strength of the synergetic effect produced by a joint effort of a number of optimization agents solving instances of one of the classic combinatorial optimization problems - the vehicle routing problem. The computational experiment carried out involved JABAT environment, which is a middleware supporting the construction of the dedicated A-Team architectures. Several types of optimization agents have been constructed and tested. The main factors in the reported experiment are structure and composition of the set of agents working in parallel on solving instances of the problem at hand.

14

Consensus of compound-order multi-agent systems with communication delays

51%

Yang H.-y. , Guo L. , Zhu X.-l. , Cao K.-c. , Zou H.-l.

Open Physics

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2013

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tom 11

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nr 6

806-812

EN

In complex environments, many distributed networked systems can only be illustrated with fractional-order dynamics. When multi-agent systems show individual diversity with difference agents, heterogeneous (integer-order and fractional-order) dynamics are used to illustrate the agent systems and compose integerfractional compounded-order systems. Applying Laplace transform and frequency domain theory of the fractional-order operator, the consensus of delayed multi-agent systems with directed weighted topologies is studied. Since an integer-order model is the special case of a fractional-order model, the results in this paper can be extended to systems with integer-order models. Finally, numerical examples are used to verify our results.

15

Analysis of incentive compatible decisions in a multicriteria auction

51%

KRUŚ L. , SKORUPIŃSKI J. , TOCZYŁOWSKI E.

Operations Research and Decisions

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2013

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tom 23

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nr 3

23-33

EN

An iterative multicriteria closed-auction conducted with the use of a multi-agent computer-based system is analyzed. This system supports the submission of offers, multicriteria analysis carried out by the organizer of the auction, simulation, and analysis of the behavior of competing bidders. Analysis of incentive compatible decisions is the main subject of this research. A mathematical formulation of the decision making problem and selected results of a bidding session conducted using this system are presented and analyzed.

16

Towards adaptive temporal planning at airports

51%

Leeuwen P. v. , Oei L. I. , Buzing P. , Vitteveen C.

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2008

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tom Vol. 34, no 4

67-77

EN

The turnaround process at airports comprises all ground handling activities that have to be performed at aircraft during their stay at an airport. Since airports are getting more and more congested with ground handling activities, the turnaround becomes one of the most constraining factors in the airport planning process. To alleviate this bottleneck, robustness of the planning of these ground handling activities is of paramount importance. In this paper, we present a simple idea to solve a strategic temporal planning problem, like the planning of ground handling processes in a way that allows unforeseen, real-time disruptions to be handled in a straightforward and elegant manner. To that end, we apply Hunsberger's temporal decoupling algorithm to a Simple Temporal Network representation of the ground handling domain. The decoupling results in a separate planning subproblem for each of the ground handling parties involved, such that they can plan and schedule their activities independently. Whatever schedule each party will choose, the decoupling guarantees that the combined schedules are feasible. This decoupling idea can be generalized and applied to develop a more robust adaptive planning system for the turnaround process.

17

A universal model of knowledge conflict resolving using consensus methods in multi-agent decision support systems

51%

Bytniewski A. , Hernes M. , Matouk K.

Informatyka Ekonomiczna

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2013

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nr 4(30)

82-90

EN

The article presents a proposition of a universal model of knowledge conflict resolving using consensus methods, which can be used in a multi-agent decision support system. Knowledge conflicts often appear, when individual agents generate different solutions of the same problem. It is very difficult for the user – decision-maker to make a good decision because the analysis of solutions generated by agents is very time-consuming and the decision must be made quickly. Moreover, selecting one of the decisions on the basis of the experience of the decision-maker is very risky, because he/she could choose the worst solution. Consensus methods, however, allow to agree, on the basis of the solutions generated by agents, one solution, which is a compromise. As a consequence, reducing the time and decreasing the risk level of the decision taking process, to enable the functioning of the enterprise in more flexible.

18

Multi-Agent Decision Taking System

51%

Wakulicz-Deja A. , Przybyła-Kasperek M.

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2010

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tom Vol. 101, nr 1/2

121-141

EN

The paper presents the process of taking global decisions on the basis of the knowledge of local decision systems involving the mutually complementary observations of objects which can be mutually contradictory. The authors suggest the organization of local decision systems into a multiagent system with a hierarchical structure. The structure of multi-agent systems and the theoretical aspects of the organization of the system are presented. A density-based algorithm has been used in the process of taking global decisions. Furthermore the paper presents the results of experiments conducted using realistic data.

19

Delayed reward in reinforcement learning: an experiment in multi-agent control.

51%

Ikonen P. , Coradeschi S. , Malec J.

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1998

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tom Vol. 98, nr 44

233-240

EN

The paper describes an approach to reinforcement multi-agent learning. Due to the domain constrains the classical immediate-reward approach is inapplicable, a delayed reward technique has been introduced. The describes the RoboCup domain used as the tested for a multi-agent system and summarizes the first, preliminary phase of experiments.

20

Multi-agent Approach to Dynamic Pick-up and Delivery Problem with Uncertain Knowledge about Future Transport Demands

51%

Koźlak J. , Créput J.-C. , Hilaire V. , Koukam A.

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2006

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tom Vol. 71, nr 1

27-36

EN

This work focuses on the dynamic Pickup and Delivery Problem with Time Windows (PDPTW). The transport requests should be performed using the available fleet of vehicles. The vehicles move between the nodes of a road network. The aim of this work is to propose a model which allows, during a transport plan creation, to take into account predictable events. Particularly, we consider the frequency of requests at any node in the road network and the construction of vehicle routes that will allow new requests to be inserted without any significant route modification. Therefore, we construct routes that pass near the nodes where transport requests are most frequently generated.