275,032 research outputs found
Distributed opportunistic argumentation guided by autonomous agent interaction
Within a distributed system, autonomous agents may find it necessary to cooperate in
order to achieve their objectives. Interaction protocols provide standard frameworks
within which to conduct common classes of interaction, but they are only useful when
the agents using them have a common interpretation of the constraints imposed by
those protocols. In open systems, where there are no system-wide objectives and components
are contributed from a variety of sources, this is difficult to ensure.
An agent within a sufficiently complex environment will find it necessary to draw
inferences from information sources of varying integrity and completeness. Given
flawed or incomplete information, it may be necessary for an agent to resort to nonmonotonic
reasoning in order to be able to make concrete decisions within limited
windows of opportunity. This can be expected to create inconsistencies in the joint
beliefs of agents which can only be repaired by dialogue between peers. To verify
and repair all possible sources of inconsistency is impractical for any sizable body of
inference however—any belief revision must therefore be subject to prioritisation.
In this thesis, we introduce a mechanism by which agents can perform opportunistic
argumentation during dialogue in order to perform distributed belief revision. An
interaction portrayal uses the protocol for a given interaction to identify the logical
constraints which must be resolved during the interaction as it unfolds. It then compares
and reconciles the expectations of agents prior to the resolution of those constraints
by generating and maintaining a system of arguments. The composition and
scope of arguments is restricted in order to minimise the information exchange whilst
still trying to ensure that all available admissible viewpoints are adequately represented
immediately prior to any decision. This serves both to make interaction more robust
(by allowing agents to make decisions based on the distributed wisdom of its peer
group without being explicitly directed by a protocol) and to reconcile beliefs in a
prioritised fashion (by focusing only on those beliefs which directly influence the outcome
of an interaction as determined by its protocol)
Towards unifying semantic constraints and security constraints in distributed information systems
Modern information systems must respect certain restrictions in order to guarantee the proper and desired functionality. Semantic constraints help to prevent inconsistencies in the stored data resulting from faulty updates. Security constraints are to maintain integrity, secrecy and availability over updates and over queries. This thesis designs a unifying framework for the specification of semantic constraints and security constraints in information systems in order to study interactions between them. We consider an information system as a distributed, reactive system in which each actor and each object acts autonomously and concurrently. Actors gain knowledge by performing read operations on objects and they may update the content of an object by performing update operations. To execute read or update operations, actors need execute rights that can be granted or revoked by other actors.This view of an information system is captured in a computational model.In this model, we consider each component of the information system, actors as well as objects, uniformly as a sequential agent that performs operations autonomously and jointly with other sequential agents. Each agent is alliated with a set of local propositions and a set of local operations as well as with relations that capture the agent's knowledge and belief. An agent's knowledge is determined completely by its local state. Change in knowledge of an agent is due to operations performed by the agent. Interaction between knowledge and operations is captured by the requirement that the enabling and the effect of an operation is completely determined by the knowledge of the acting agents. Knowledge of agents can be changed only byoperations in which they participate. We define a temporal and epistemic specification language with temporaland epistemic operators. The logic provides for each agent local next and until operators as temporal operators and local knowledge and belief operators as epistemic operators. We develop a modal tableau based proof system for a subset of the logic and show its soundness. Completeness can be shown only for a smaller, but still reasonable subset of the logic, decidability remains an open question. The main diffculty of the tableau system arises from the interaction requirement between knowledge and action.In a detailed example we demonstrate how the framework can be used for specifying semantic constraints and security constraints in information systems
Virtual Neurorobotics (VNR) to Accelerate Development of Plausible Neuromorphic Brain Architectures
Traditional research in artificial intelligence and machine learning has viewed the brain as a specially adapted information-processing system. More recently the field of social robotics has been advanced to capture the important dynamics of human cognition and interaction. An overarching societal goal of this research is to incorporate the resultant knowledge about intelligence into technology for prosthetic, assistive, security, and decision support applications. However, despite many decades of investment in learning and classification systems, this paradigm has yet to yield truly “intelligent” systems. For this reason, many investigators are now attempting to incorporate more realistic neuromorphic properties into machine learning systems, encouraged by over two decades of neuroscience research that has provided parameters that characterize the brain's interdependent genomic, proteomic, metabolomic, anatomic, and electrophysiological networks. Given the complexity of neural systems, developing tenable models to capture the essence of natural intelligence for real-time application requires that we discriminate features underlying information processing and intrinsic motivation from those reflecting biological constraints (such as maintaining structural integrity and transporting metabolic products). We propose herein a conceptual framework and an iterative method of virtual neurorobotics (VNR) intended to rapidly forward-engineer and test progressively more complex putative neuromorphic brain prototypes for their ability to support intrinsically intelligent, intentional interaction with humans. The VNR system is based on the viewpoint that a truly intelligent system must be driven by emotion rather than programmed tasking, incorporating intrinsic motivation and intentionality. We report pilot results of a closed-loop, real-time interactive VNR system with a spiking neural brain, and provide a video demonstration as online supplemental material
Performance assessment of security mechanisms for cooperative mobile health applications
Mobile health (m-Health) applications aim to deliver healthcare services through mobile applications regardless of time and place. An mHealth application makes use of wireless communications to sustain its health services and often providing a patient-doctor interaction. Therefore, m-Health applications present several challenging issues and constraints, such as, mobile devices battery and storage capacity, broadcast constraints, interferences, disconnections, noises, limited bandwidths, network delays, and of most importance, privacy and security concerns. In a typical m-Health system, information transmitted through wireless channels may contain sensitive information such as patient’s clinic history, patient’s personal diseases information (e.g. infectious disease as HIV - human immunodeficiency virus). Carrying such type of information presents many issues related to its privacy and protection. In this work, a cryptographic solution for m-Health applications under a cooperative environment is proposed in order to approach two common drawbacks in mobile health systems: the data privacy and protection. Two different approaches were proposed: i) DE4MHA that aims to guarantee the best confidentiality, integrity, and authenticity of mhealth systems users data and ii) eC4MHA that also focuses on assuring and guarantying the m-Health application data confidentiality, integrity, and authenticity, although with a different paradigm. While DE4MHA considers a peer-to-peer node message forward, with encryption/decryption tasks on each node, eC4MHA focuses on simply encrypting data at the requester node and decrypting it when it reaches the Web service. It relays information through cooperative mobile nodes, giving them the only strictly required information, in order to be able to forward a request, until it reaches the Web service responsible to manage the request, and possibly answer to that same request. In this sense, the referred solutions aim any mobile health application with cooperation mechanism embedded. For test purposes a specific mobile health application, namely SapoFit, was used. Cryptographic mechanisms were created and integrated in SapoFit application with built in cooperation mechanisms. A performance evaluation of both approaches in a real scenario with different mobile devices is performed and presented in this work. A comparison with the performance evaluations of both solutions is also presented.Fundação para a Ciência e a Tecnologia (FCT)European Community Fund FEDER through COMPETE – Programa Operacional Factores de Competitividad
CamFlow: Managed Data-sharing for Cloud Services
A model of cloud services is emerging whereby a few trusted providers manage
the underlying hardware and communications whereas many companies build on this
infrastructure to offer higher level, cloud-hosted PaaS services and/or SaaS
applications. From the start, strong isolation between cloud tenants was seen
to be of paramount importance, provided first by virtual machines (VM) and
later by containers, which share the operating system (OS) kernel. Increasingly
it is the case that applications also require facilities to effect isolation
and protection of data managed by those applications. They also require
flexible data sharing with other applications, often across the traditional
cloud-isolation boundaries; for example, when government provides many related
services for its citizens on a common platform. Similar considerations apply to
the end-users of applications. But in particular, the incorporation of cloud
services within `Internet of Things' architectures is driving the requirements
for both protection and cross-application data sharing.
These concerns relate to the management of data. Traditional access control
is application and principal/role specific, applied at policy enforcement
points, after which there is no subsequent control over where data flows; a
crucial issue once data has left its owner's control by cloud-hosted
applications and within cloud-services. Information Flow Control (IFC), in
addition, offers system-wide, end-to-end, flow control based on the properties
of the data. We discuss the potential of cloud-deployed IFC for enforcing
owners' dataflow policy with regard to protection and sharing, as well as
safeguarding against malicious or buggy software. In addition, the audit log
associated with IFC provides transparency, giving configurable system-wide
visibility over data flows. [...]Comment: 14 pages, 8 figure
Constraints for Semistructured Data and XML
Integrity constraints play a fundamental role in database design. We review initial work on the expression of integrity constraints for semistructured data and XML
Geospatial Narratives and their Spatio-Temporal Dynamics: Commonsense Reasoning for High-level Analyses in Geographic Information Systems
The modelling, analysis, and visualisation of dynamic geospatial phenomena
has been identified as a key developmental challenge for next-generation
Geographic Information Systems (GIS). In this context, the envisaged
paradigmatic extensions to contemporary foundational GIS technology raises
fundamental questions concerning the ontological, formal representational, and
(analytical) computational methods that would underlie their spatial
information theoretic underpinnings.
We present the conceptual overview and architecture for the development of
high-level semantic and qualitative analytical capabilities for dynamic
geospatial domains. Building on formal methods in the areas of commonsense
reasoning, qualitative reasoning, spatial and temporal representation and
reasoning, reasoning about actions and change, and computational models of
narrative, we identify concrete theoretical and practical challenges that
accrue in the context of formal reasoning about `space, events, actions, and
change'. With this as a basis, and within the backdrop of an illustrated
scenario involving the spatio-temporal dynamics of urban narratives, we address
specific problems and solutions techniques chiefly involving `qualitative
abstraction', `data integration and spatial consistency', and `practical
geospatial abduction'. From a broad topical viewpoint, we propose that
next-generation dynamic GIS technology demands a transdisciplinary scientific
perspective that brings together Geography, Artificial Intelligence, and
Cognitive Science.
Keywords: artificial intelligence; cognitive systems; human-computer
interaction; geographic information systems; spatio-temporal dynamics;
computational models of narrative; geospatial analysis; geospatial modelling;
ontology; qualitative spatial modelling and reasoning; spatial assistance
systemsComment: ISPRS International Journal of Geo-Information (ISSN 2220-9964);
Special Issue on: Geospatial Monitoring and Modelling of Environmental
Change}. IJGI. Editor: Duccio Rocchini. (pre-print of article in press
Interoperability, Trust Based Information Sharing Protocol and Security: Digital Government Key Issues
Improved interoperability between public and private organizations is of key
significance to make digital government newest triumphant. Digital Government
interoperability, information sharing protocol and security are measured the
key issue for achieving a refined stage of digital government. Flawless
interoperability is essential to share the information between diverse and
merely dispersed organisations in several network environments by using
computer based tools. Digital government must ensure security for its
information systems, including computers and networks for providing better
service to the citizens. Governments around the world are increasingly
revolving to information sharing and integration for solving problems in
programs and policy areas. Evils of global worry such as syndrome discovery and
manage, terror campaign, immigration and border control, prohibited drug
trafficking, and more demand information sharing, harmonization and cooperation
amid government agencies within a country and across national borders. A number
of daunting challenges survive to the progress of an efficient information
sharing protocol. A secure and trusted information-sharing protocol is required
to enable users to interact and share information easily and perfectly across
many diverse networks and databases globally.Comment: 20 page
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