Abstract: The increased availability of mobile broadband connections enables the expansion of software downloads to mobile devices. This leads to greater number of available services and a better utilisation of the computational power of mobile devices. The downside of this increased software availability is an increase in the possible attack vectors. One scenario is the misuse of resources, for example, a game is sending more SMS’s than the user wishes it to send. Thus, techniques need to be in place that prevent downloaded software from misusing resources on the mobile device. In this paper, we show how it is possible to prevent such misuse of resources through the use of a runtime monitor that performs execution-time checks to monitor if the application is behaving correctly or not. This runtime monitor enhances the flexibility of the Java security model for mobile devices and allows to enforce security policies without having to rely on signatures of the downloaded applications.
Abstract: Distributed energy resource management involves matching the production of and demand for power in electrical grids. This leads to the question, where should responsibility for resource use be placed? A number of potential management schemes exist in current work on complex large-scale distributed computer systems. This paper works towards a comparison of their relative performance. A test scenario is designed, based on the concept of a virtual power station. Simulations are run, using input data from an actual system, to produce estimates of the overall cost of electricity in a virtual power station over a given period. Results are presented that examine the effect of improving or weakening management precision at various points. These indicate that fairly weak management techniques may be sufficient. While the presence of a number of forms of management, including central control, local autonomous control, and variation of group composition, is significant, improved management does not bring very large additional benefits. This can have important implications when designing virtual power station implementations. For instance it indicates low-grade communication networks and control devices may provide the best return on investment.
Abstract: Secure deployment of agents in open, insecure environments is a challenge, for which a number of multi-agent system (MAS) frameworks have been designed. Secure deployment of BDI-based MAS in such environments, however, has yet to be addressed. This paper proposes an architecture to securely support large-scale, heterogeneous, BDI-based multi-agent systems, using JASON and AgentScape to illustrate the approach. An example scenario in which BDI agents negotiate the price of electricity in an open energy market sets the stage.
Abstract: Simulations of crisis scenarios have the potential to increase insight in the organizational
structures needed as crises escalate. Real-life simulations involving personnel and figurants are
expensive and time-consuming. Multi-agent system models allow for cost-effective simulations
of changing organizational structures, enabling analysis of the implications for enactment during
crisis escalation with respect to roles and communication structures.
This paper presents both an organization-based model for crisis management that supports simulation of the
dynamics of crisis management and a proof of concept implementation.
Abstract: Mobile agents traverse the Internet, often on behalf of their users. Intelligent search agents access dynamic information in heterogeneous environments. The legal implications of the use of agents in such situations are not fully understood. In this paper a scenario in which a mobile agent searches a multimedia database on behalf of its user, is used to illustrate the legal and technical issues involved. Requirements related to identity management, integrity, traceability and availability are identified and discussed in the context of existing technology.
Abstract: Service Level Agreements require a monitoring system that checks that no party violates the agreement. Current monitoring techniques either have a high performance overhead or are not reliable enough. This paper proposes a new theoretical hybrid monitoring system that we call reactive monitoring. It tries to balance the disadvantages of established monitoring techniques, in particular online and offline monitoring. Online monitoring has a relatively high performance overhead and offline monitoring does not identify all possible violations.
Reactive monitoring combines online monitoring, which is used for reactively checking continuous SLA properties with a new passive monitoring scheme. This scheme is used for monitoring discrete SLA properties. It is based on cryptographic primitives that provide proof that either a certain stage in an interaction has been reached correctly with all participants in compliance of the service level agreements or that a violation has occurred. In the latter case the violating party can be identified.
A theoretical analysis shows that in the worst case scenario this new approach has the same overhead as online monitoring techniques and in most cases the overhead will be significantly lower.
Abstract: In this paper it is shown how informal and formal specification of behavioural requirements and scenarios for agents and multi-agent systems can be integrated within multi-agent system design. In particular, it is addressed how a compositional perspective both on design descriptions and specification of behavioural requirements can be exploited. The approach has been applied in a case study: the development of a mediating information agent. It is shown that compositional verification benefits from the integration of requirements engineering within the design process.
Abstract: Self-monitoring of autonomic distributed systems requires knowledge of the
states and events of many different parts of a system. One of the main
challenges is to determine which information is most crucial for analysis of
a system's behaviour, and when. This paper proposes a model-based approach
to self-monitoring for which structural and behavioural models of a system
are described at different levels: application, subsystem, component and
class level. In this approach, a system's behaviour is monitored in the
context of a hierarchy of use-cases related to these levels. The structural
and behavioural models are used to automatically instrument an existing
distributed system. The proposed architecture of a self-monitoring engine is
described as is the implementation. The models have been specified in the
Ontology Web Language (OWL) and the self-monitoring (as a part of our
self-management framework) has been implemented in Java. The scenario used
to illustrate the approach is that of authentication for a simplified
version of a distributed portal application.
Abstract: This paper introduces the notion of witnessed presence arguing that the performative act of witnessing presence is fundamental to dynamics of negotiating trust and truth. As the agency of witnessed presence in mediated presence differs from natural presence orchestration between natural and mediated presences is needed. The YUTPA framework, introduced in this paper, depicts 4 dimensions to define witnessed presence: time, place, action and relation. This framework also provides a context for design of trust in products and services, as illustrated for a number of illustrative scenarios.
