Maggie R. Breedy

KAoS policy and domain services: toward a description-logic approach to policy representation, deconfliction, and enforcement

We describe our initial implementation of the KAoS policy and domain services. While primarily oriented to the dynamic and complex requirements of software agent applications, the services are also being adapted to general-purpose grid computing and Web services environments as well. The KAoS services rely on a DAML description-logic-based ontology of the computational environment, application context, and the policies themselves that enables runtime extensibility and adaptability of the system, as well as the ability to analyze policies relating to entities described at different levels of abstraction.

Representation and reasoning for DAML-based policy and domain services in KAoS and nomads

To increase the assurance with which agents can be deployed in operational settings, we have been developing the KAoS policy and domain services. In conjunction with Nomads strong mobility and safe execution features, KAoS services and tools allow for the specification, management, conflict resolution, and enforcement of DAML-based policies within the specific contexts established by complex organizational structures. In this paper, we will discuss results, issues, and lessons learned in the development of these representations, tools, and services and their use in military and space application.

Strong Mobility and Fine-Grained Resource Control in NOMADS

NOMADS is a Java-based agent system that supports strong mobility (i.e., the ability to capture and transfer the full execution state of migrating agents) and safe agent execution (i.e., the ability to control resources consumed by agents, facilitating guarantees of quality of service while protecting against denial of service attacks). The NOMADS environment is composed of two parts: an agent execution environment called Oasis and a new Java-compatible Virtual Machine (VM) called Aroma. The combination of Oasis and the Aroma VM provides key enhancements over today’s Java agent environments.

New Developments in Ontology-Based Policy Management: Increasing the Practicality and Comprehensiveness of KAoS

The KAoS policy management framework pioneered the use of semantically-rich ontological representation and reasoning to specify, analyze, deconflict, and enforce policies [9, 10]. The framework has continued to evolve over the last five years, inspired by both technological advances and the practical needs of its varied applications. In this paper, we describe how these applications have motivated the partitioning of components into a well-defined three-layer policy management architecture that hides ontology complexity from the human user and from the policy-governed system. The power of semantic reasoning is embedded in the middle layer of the architecture where it can provide the most benefit. We also describe how the policy semantics of the core KAoS policy ontology has grown in its comprehensiveness. The flexible and mature architecture of KAoS enables straightforward integration with a variety of deployment platforms, ranging from highly distributed systems, such as the AFRL information management system, to human-robotic interaction, to dynamic management of quality-of-service and cross-domain information management of wireless networks in resource-constrained or security-sensitive environments.

Mobile-Agent versus Client/Server Performance: Scalability in an Information-Retrieval Task

Building applications with mobile agents often reduces the bandwidth required for the application, and improves performance. The cost is increased server workload. There are, however, few studies of the scalability of mobile-agent systems. We present scalability experiments that compare four mobile-agent platforms with a traditional client/server approach. The four mobile-agent platforms have similar behavior, but their absolute performance varies with underlying implementation choices. Our experiments demonstrate the complex interaction between environmental, application, and system parameters.

NOMADS: toward a strong and safe mobile agent system

NOMADS is a mobile agent system that supports strong mobility (i.e., the ability to capture and transfer the full execution state of mobile agents) and safe Java agent execution (i.e., the ability to control resources consumed by agents, facilitating guarantees of quality of service while protecting against denial of service attacks). The NOMADS environment is composed of two parts: an agent execution environment called Oasis and a new Javacompatible Virtual Machine (VM) called Aroma. The combination of Oasis and the Aroma VM provides key enhancements over todays Java agent environments.

Supporting Flexible Data Feeds in Dynamic Sensor Grids through Mobile Agents

This paper describes a framework for flexible data feeds in sensor grids where resource constraints, policies, and a dynamic topology are important factors. Mobile agents are used to dynamically establish the data flows and data transformations in the network. They also act as policy enforcers that are dynamically dispatched into the sensor network. A dynamic topology for the network is taken into consideration, where nodes can join and leave at any time. Mobile code provides the means to dynamically deploy capabilities to any participating host and strong mobility allows process migration between nodes to ensure feed survivability and load balancing. The proposed framework relies on a strong mobility agent system (NOMADS) and the KAoS framework for policy enforcement and is being currently used to support a military coalition agent scenario (CoAX 2002).

Enforcement of communications policies in software agent systems through mobile code

We introduce the use of mobile agents as the mechanism for policy enforcement in multiagent multidomain systems. The focus is on the effective application of communication policies in the setup and maintenance of spanning data streams that cross multiple hosts in different domains. We have designed and implemented a mobile agent based framework (FlexFeed) that works in concert with the KAoS framework for policy management.

DAML-based policy enforcement for semantic data transformation and filtering in multi-agent systems

This paper describes an approach to runtime policy-based control over information exchange that allows a far more fine-grained control of these dynamically discovered agent interactions. The DARPA Agent Markup Language (DAML) is used to represent policies that may either filter messages based on their semantic content or transform the messages to make them suitable to be released. Policy definition, management, and enforcement are realized as part of the KAoS architecture. The solutions presented have been tested in the Coalition Agents Experiment (CoAX) - an experiment involving coalition military operations.

Software agents for process monitoring and notification

Safety and efficiency are primary concerns in chemical processing facilities, though the complexity of many such systems often makes it difficult for operators to detect abnormal conditions before they compromise throughput or become hazardous. In this paper, we report initial results from the application of multi-agent systems to monitor complex chemical processes and flexibly and appropriately notify key plant personnel about off-nominal conditions.