14 research outputs found
A SURVEY OF THE PROPERTIES OF AGENTS
In the past decade agent systems were considered to be as one of the major fields of study in Artificial Intelligence (AI) field. Many different definitions of agents were presented and several different approaches describing agency can be distinguished. While some authors have tried to define “what” an agent really is, others have tried to identify agents by means of properties which they should possess. Most authors agree on these properties (at least basic set of properties) which are intrinsic to agents. Since agent\u27s definitions are not consistent, we are going to give an overview and list the properties intrinsic to an agent. Many different adjectives were attached to the term agent as well and many different kinds of agents and different architectures emerged too. The aim of this paper it go give an overview of what was going on in the field while taking into consideration main streams and projects. We will also present some guidelines important when modelling agent systems and say something about security issues. Also, some existing problems which restrict the wider usage of agents will be mentioned too
Pervasive surveillance-agent system based on wireless sensor networks: design and deployment
Nowadays, proliferation of embedded systems is enhancing the possibilities of gathering information by using wireless sensor networks (WSNs). Flexibility and ease of installation make these kinds of pervasive networks suitable for security and surveillance environments. Moreover, the risk for humans to be exposed to these functions is minimized when using these networks. In this paper, a virtual perimeter surveillance agent, which has been designed to detect any person crossing an invisible barrier around a marked perimeter and send an alarm notification to the security staff, is presented. This agent works in a state of 'low power consumption' until there is a crossing on the perimeter. In our approach, the 'intelligence' of the agent has been distributed by using mobile nodes in order to discern the cause of the event of presence. This feature contributes to saving both processing resources and power consumption since the required code that detects presence is the only system installed. The research work described in this paper illustrates our experience in the development of a surveillance system using WNSs for a practical application as well as its evaluation in real-world deployments. This mechanism plays an important role in providing confidence in ensuring safety to our environment
Synthesis of minimum-cost shields for multi-agent systems
In this paper, we propose a general approach to derive runtime enforcement implementations for multiagent systems, called shields, from temporal logical specifications. Each agent of the multi-agent system is monitored, and if needed corrected, by the shield, such that a global specification is always satisfied. The different ways of how a shield can interfere with each agent in the system in case of an error introduces the need for quantitative objectives. This work is the first to discuss the shield synthesis problem with quantitative objectives. We provide several cost functions that are utilized in the multi-agent setting and provide methods for the synthesis of cost-optimal shields and fair shields, under the given assumptions on the multi-agent system. We demonstrate the applicability of our approach via a detailed case study on UAV mission planning for warehouse logistics and simulating the shielded multi-agent system on ROS/Gazebo
A Rewriting Logic Approach to Stochastic and Spatial Constraint System Specification and Verification
This paper addresses the issue of specifying, simulating, and verifying
reactive systems in rewriting logic. It presents an executable semantics for
probabilistic, timed, and spatial concurrent constraint programming ---here
called stochastic and spatial concurrent constraint systems (SSCC)--- in the
rewriting logic semantic framework. The approach is based on an enhanced and
generalized model of concurrent constraint programming (CCP) where
computational hierarchical spaces can be assigned to belong to agents. The
executable semantics faithfully represents and operationally captures the
highly concurrent nature, uncertain behavior, and spatial and epistemic
characteristics of reactive systems with flow of information. In SSCC, timing
attributes ---represented by stochastic duration--- can be associated to
processes, and exclusive and independent probabilistic choice is also
supported. SMT solving technology, available from the Maude system, is used to
realize the underlying constraint system of SSCC with quantifier-free formulas
over integers and reals. This results in a fully executable real-time symbolic
specification that can be used for quantitative analysis in the form of
statistical model checking. The main features and capabilities of SSCC are
illustrated with examples throughout the paper. This contribution is part of a
larger research effort aimed at making available formal analysis techniques and
tools, mathematically founded on the CCP approach, to the research community.Comment: arXiv admin note: text overlap with arXiv:1805.0743
Computer Aided Verification
This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency
The 1989 Goddard Conference on Space Applications of Artificial Intelligence
The following topics are addressed: mission operations support; planning and scheduling; fault isolation/diagnosis; image processing and machine vision; data management; and modeling and simulation
Computer Aided Verification
This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency
Ambientes virtuais povoados com simulação eficiente de detecção de colisões e planeamento de trajectos em navegação realmente 3D
Tese de Doutoramento - Área de InformáticaA tecnologia de produção de ambientes virtuais tem vindo cada vez mais a ser utilizada em projectos de animação, desenho e avaliação em diversas áreas. Mundos virtuais com níveis de detalhe consideráveis estão a começar a emergir em toda a parte, desde largas áreas das
actuais cidades até ambientes virtuais interiores mais específicos e detalhados (edifícios
habitacionais, estádios, estruturas industriais, reconstruções arqueológicas, etc). No entanto,
melhorar a aparência visual destes edifícios virtuais já não é suficiente. Com o propósito de
proporcionar novas condições de simulação a aplicações tais como o planeamento urbano,
simulações comportamentais e de fluxo de pedestres, entretenimento, etc, é necessário o
povoamento destes ambientes. Povoar estes mundos simulando a presença de vida, adiciona
um toque extra à visualização e realismo, mas infelizmente traz também carga adicional ao
sistema. Uma das lacunas da pesquisa nesta área é a representação eficiente de ambientes
densamente povoados, com simulação de navegação autónoma realmente tridimensional das
personagens, enquadradas em modelos ou cenários arbitrários. Diversas condições e áreas de
actuação são necessárias quando pretendemos simular a presença humana (através de
personagens sintéticas animadas) nestas circunstâncias, tais como a detecção de colisões,
planeamento de trajectos, algoritmos comportamentais, rendering dinâmico da geometria,
entre outros.
Nesta tese, é publicado um método transversal de modo a exibir e consolidar
comportamentos autónomos de multidões virtuais em ambientes reais de animação. O
sistema tem a capacidade de incluir um grande número de personagens lidando com mundos
3D arbitrariamente complexos, não requerendo qualquer conhecimento prévio da
geometria, e proporcionando navegação em tempo real, autónoma, e tridimensional.
Inicialmente, é apresentado um método de detecção de colisões usando técnicas
conservadoras, capaz de comportar milhares de avatares e lidar com cenas 3D de grandes
dimensões e complexidade, não necessitando de qualquer informação ou conhecimento
prévio do modelo. Este método demonstrou ser um mecanismo eficiente e escalável de
detecção de colisões entre os agentes e o ambiente 3D. Recorrendo a um mapeamento e
extracção de dados automático a partir do modelo inicial, fornece a detecção de colisões e a
interacção entre os próprios agentes virtuais, e os agentes virtuais e o ambiente que os
rodeia. Este método mostrou-se apropriado como base de implementação posterior de
algoritmos de planeamento de percursos e outros algoritmos comportamentais, onde o avatar
incorporará procedimentos de mais alto-nível.
Para projectos de desenho, simulação e testes de facilidades de navegação em locais públicos,
é importante prever as principais rotas ou fluxos a serem usados. Uma segunda aproximação
apresentada, consiste em decompor a cena 3D em partições multi-nível (para navegação em
ambientes 3D, principalmente em interiores de edifícios) criando um sistema que possa usar
este tipo de catalogação como informação relevante de modo a planear rotas de acordo com
as deslocações em várias alturas.
A outro nível, o objectivo foi também testar a base de navegação criada, desenvolvendo
mecanismos de implementação de novos e naturais comportamentos associados à navegação
das personagens virtuais, lidando com várias variáveis de interacção, permitindo um
comportamento mais realista e de reacção entre estes e o ambiente virtual. Em resumo,
foram definidos sistemas de condições, regras e propriedades capazes de produzir
comportamentos mais naturais e autónomos em personagens virtuais representativos da
conduta humana.Virtual environment technology has been increasingly used for animation projects, design and evaluation in several areas. Virtual worlds, with considerable levels of detail, are starting to emerge everywhere, from large areas of actual cities to detailed and complex virtual indoor environments (buildings, stadiums, industrials structures, archaeological
reconstructions, etc). However, improving the visual appearance of these virtual buildings is not enough anymore. In order to provide applications with new simulation conditions such as urban planning, behaviour and flow of pedestrian’s simulation, entertainment, etc, requires the populating of these virtual environments. Populating these worlds to simulate the presence of life, adds an extra touch to the visualization and credibility, but unfortunately it also brings an extra burden to the system. One of the issues of the research in this area is the representation of a densely crowded environment, simulating autonomous and real three-dimensional navigation to the virtual characters in arbitrary threedimensional models or scenarios. Several steps are required when we need simulate the human presence (by synthetic animated characters) in these circumstances, such as collision detection, path planning/finding, behavioural algorithms, dynamic rendering of geometry, amongst others.
In this thesis, a transversal approach is presented to demonstrate and consolidate autonomous virtual crowd behaviours in realistic animation environments. The system is able to include a large number of characters dealing with arbitrarily complex 3D worlds, not requiring any prior knowledge of the geometry, and providing real-time navigation,
autonomous, and really three-dimensional.
Initially, a method for efficient and scalable conservative collision detection is presented, that is able to deal with large and complex 3D scenes with thousands of avatars, not requiring any prior knowledge of model. This method demonstrated to be a fast, efficient and scalable collision detection process between virtual agents and the 3D environment. Using an automatic data extraction and mapping process from the initial graphical model, it provides collisions detection and interaction between virtual agents, as well as virtual agents and the environment that encircles them. This method proved to be appropriate as a basis for further implementation of path planning/finding algorithms and other behaviours algorithms.
For design projects, simulation and the study of crowd behaviour facilities in public places, it is however important to be able to predict heavily used routes or peak flows. The second approach presented, consists in decomposing the 3D scene in multi-level sub-divisions (for navigation in 3D environments such as indoor building) creating a system that can use this type of cataloguing as relevant information to planning and finding routes, according to the movements at the various levels of heights.
At another level, the goal was testing the base of navigation, developing mechanisms for new and natural behaviour implementations associated with virtual characters navigation, dealing with some interaction variables, representing a more realistic react/interact behaviour. In summary, autonomous conditions systems, rules and properties were defined, that are capable to produce behaviours representative of human condition
Ambientes virtuais povoados com simulação eficiente de detecção de colisões e planeamento de trajectos em navegação realmente 3D
Tese Phd - Área Computação Gráfica e Inteligencia ArtificialA tecnologia de produção de ambientes virtuais tem vindo cada vez mais a ser utilizada em
projectos de animação, desenho e avaliação em diversas áreas. Mundos virtuais com níveis de
detalhe consideráveis estão a começar a emergir em toda a parte, desde largas áreas das
actuais cidades até ambientes virtuais interiores mais específicos e detalhados (edifícios
habitacionais, estádios, estruturas industriais, reconstruções arqueológicas, etc). No entanto,
melhorar a aparência visual destes edifícios virtuais já não é suficiente. Com o propósito de
proporcionar novas condições de simulação a aplicações tais como o planeamento urbano,
simulações comportamentais e de fluxo de pedestres, entretenimento, etc, é necessário o
povoamento destes ambientes. Povoar estes mundos simulando a presença de vida, adiciona
um toque extra à visualização e realismo, mas infelizmente traz também carga adicional ao
sistema. Uma das lacunas da pesquisa nesta área é a representação eficiente de ambientes
densamente povoados, com simulação de navegação autónoma realmente tridimensional das
personagens, enquadradas em modelos ou cenários arbitrários. Diversas condições e áreas de
actuação são necessárias quando pretendemos simular a presença humana (através de
personagens sintéticas animadas) nestas circunstâncias, tais como a detecção de colisões,
planeamento de trajectos, algoritmos comportamentais, rendering dinâmico da geometria,
entre outros.
Nesta tese, é publicado um método transversal de modo a exibir e consolidar
comportamentos autónomos de multidões virtuais em ambientes reais de animação. O
sistema tem a capacidade de incluir um grande número de personagens lidando com mundos
3D arbitrariamente complexos, não requerendo qualquer conhecimento prévio da
geometria, e proporcionando navegação em tempo real, autónoma, e tridimensional.
Inicialmente, é apresentado um método de detecção de colisões usando técnicas
conservadoras, capaz de comportar milhares de avatares e lidar com cenas 3D de grandes
dimensões e complexidade, não necessitando de qualquer informação ou conhecimento
prévio do modelo. Este método demonstrou ser um mecanismo eficiente e escalável de
detecção de colisões entre os agentes e o ambiente 3D. Recorrendo a um mapeamento e
extracção de dados automático a partir do modelo inicial, fornece a detecção de colisões e a
interacção entre os próprios agentes virtuais, e os agentes virtuais e o ambiente que os
rodeia. Este método mostrou-se apropriado como base de implementação posterior de
algoritmos de planeamento de percursos e outros algoritmos comportamentais, onde o avatar
incorporará procedimentos de mais alto-nível. Para projectos de desenho, simulação e testes de facilidades de navegação em locais públicos,
é importante prever as principais rotas ou fluxos a serem usados. Uma segunda aproximação
apresentada, consiste em decompor a cena 3D em partições multi-nível (para navegação em
ambientes 3D, principalmente em interiores de edifícios) criando um sistema que possa usar
este tipo de catalogação como informação relevante de modo a planear rotas de acordo com
as deslocações em várias alturas.
A outro nível, o objectivo foi também testar a base de navegação criada, desenvolvendo
mecanismos de implementação de novos e naturais comportamentos associados à navegação
das personagens virtuais, lidando com várias variáveis de interacção, permitindo um
comportamento mais realista e de reacção entre estes e o ambiente virtual. Em resumo,
foram definidos sistemas de condições, regras e propriedades capazes de produzir
comportamentos mais naturais e autónomos em personagens virtuais representativos da
conduta humana. Virtual environment technology has been increasingly used for animation projects, design and evaluation in several areas. Virtual worlds, with considerable levels of detail, are starting to emerge everywhere, from large areas of actual cities to detailed and complex virtual indoor environments (buildings, stadiums, industrials structures, archaeological reconstructions, etc). However, improving the visual appearance of these virtual buildings is not enough anymore. In order to provide applications with new simulation conditions such as urban planning, behaviour and flow of pedestrian’s simulation, entertainment, etc, requires the populating of these virtual environments. Populating these worlds to simulate the presence of life, adds an extra touch to the visualization and credibility, but unfortunately it also brings an extra burden to the system. One of the issues of the research in this area is the representation of a densely crowded environment, simulating autonomous and real three-dimensional navigation to the virtual characters in arbitrary three-dimensional models or scenarios. Several steps are required when we need simulate the human presence (by synthetic animated characters) in these circumstances, such as collision detection, path planning/finding, behavioural algorithms, dynamic rendering of geometry, amongst others.
In this thesis, a transversal approach is presented to demonstrate and consolidate autonomous virtual crowd behaviours in realistic animation environments. The system is able to include a large number of characters dealing with arbitrarily complex 3D worlds, not requiring any prior knowledge of the geometry, and providing real-time navigation, autonomous, and really three-dimensional.
Initially, a method for efficient and scalable conservative collision detection is presented, that is able to deal with large and complex 3D scenes with thousands of avatars, not requiring any prior knowledge of model. This method demonstrated to be a fast, efficient and scalable collision detection process between virtual agents and the 3D environment.
Using an automatic data extraction and mapping process from the initial graphical model, it provides collisions detection and interaction between virtual agents, as well as virtual agents and the environment that encircles them. This method proved to be appropriate as a basis for further implementation of path planning/finding algorithms and other behaviours algorithms. For design projects, simulation and the study of crowd behaviour facilities in public places, it is however important to be able to predict heavily used routes or peak flows. The second approach presented, consists in decomposing the 3D scene in multi-level sub-divisions (for navigation in 3D environments such as indoor building) creating a system that can use this type of cataloguing as relevant information to planning and finding routes, according to the movements at the various levels of heights.
At another level, the goal was testing the base of navigation, developing mechanisms for new and natural behaviour implementations associated with virtual characters navigation, dealing with some interaction variables, representing a more realistic react/interact behaviour. In summary, autonomous conditions systems, rules and properties were defined, that are capable to produce behaviours representative of human condition.Uminho, IP