A multiagent telemedicine system

In this paper we propose a telemedicine sytem model based on multiagent systems. Then, we develop a simulator based on this model. The system is composed of seven agents, such as: a medical database management agent, an application agent, and a planning agent. Some simulations are presented to evaluate the performance of our system. The simulator was developed using JAFMAS (Java-based Agent Framework for Multiagent Systems).     

Agent Cooperation Based Control Integration by Activity-Sharing and Joint Intention

In this paper,a control integration method based on agent cooperation,called ASOJI,is proposed,which designs the architecture of integrated application systems in distributed computation environments as an agent community composed of nested agent fed-erations in three aspects:architecture style,agent cooperation,and composition semantics.Through defining activity-sharing-orented joint intention in the way of stepwise refinement,ASOJI can not only support the transparent specification of the architecture for software com-position,but also eliminate the gap between agent theory and the engineering realiztion of control integration.     

Composing web services enacted by autonomous agents through agent-centric contract net protocol

ContextAgents are considered as one of the fundamental technologies underlying open and dynamic systems that are largely enabled by the semantic web and web services. Recently, there is a trend to introduce the notion of autonomy empowered by agents into web services. However, it has been argued that the characteristics of autonomy will make agents become available intermittently and behave variedly over time, which therefore increase the complexity on devising mechanisms for composing services enacted by autonomous agents.ObjectiveIn this work, we propose an extension to Contract Net protocol, called Agent-centric Contract Net Protocol (ACNP), as a negotiation mechanism with three key features for composing web services enacted by autonomous agents.Method(1) A matchmaking mechanism embedded in a middle agent (as a service matchmaker) for discovering web services that are available intermittently is presented based on the concept of agent roles; (2) A selection algorithm based on risk-enabled reputation model (REAL) embedded in a manager agent (as a service composer) is introduced to serve a basis for selecting web services with variant performance; and (3) A negotiation mechanism between a manager agent and contractor agents (as atomic services) is devised and enables both a service composer and the atomic services to request, refuse or agree on adapting changes of services.ResultsThe problem of assembling a computer is discussed in this paper.ConclusionIt is increasingly recognised that web services would become more autonomous by introducing diverse agent technologies to better constitute more complex systems in open and dynamic environments. As web service technologies are best exploited by composite services, it is imperative to devise mechanisms for composing services of autonomy.     

Verifying Object-based Graph Grammars

The development of concurrent and reactive systems is gaining importance since they are well-suited to modern computing platforms, such as the Internet. However, the development of correct concurrent and reactive systems is a non-trivial task. Object-based graph grammar (OBGG) is a visual formal language suitable for the specification of this class of systems. In previous work, a translation from OBGG to PROMELA (the input language of the SPIN model checker) was defined, enabling the verification of OBGG models using SPIN. In this paper we extend this approach in two different ways: (1) the approach for property specification is improved, enabling to prove properties not only about possible OBGG derivations, but also about the internal state of involved objects; (2) an approach is defined to interpret PROMELA races as OBGG derivations, generating graphical counter-examples for properties that are not true for a given OBGG model. Another contribution of this paper is (3) the definition of a method for model checking partial systems (isolated objects or a set of objects) using an assume-guarantee approach. A gas station system modeled with OBGGs is used to illustrate the contributions.This work is partially sponsored by projects IQ-MObile (CNPq-Brazil/CNR-Italy) and PLATUS (CNPq).Osmar Marchi dos Santos is partially sponsored by CAPES-Brazil.     

On the sources of complexity in agent design

This article addresses the question of what makes agent design hard. This is a fundamental issue not just for the intelligent agents community, but also for the computer science and software engineering communities in general. The article begins by presenting a simple, informal model of agents and their environments, and then uses this model to frame a discussion on the sources of complexity in agent design. Three key sources of complexity are identified: the agent's environment, the nature of interaction between agent and environment, and the nature of the specification or task for the agent. Following this discussion, the article presents a simple formal model of agents and their environments, which is capable of representing many of these sources of complexity. Using the formal model, a number of stereotypical agent design problems are defined. The article concludes with a discussion of related work and issues.     

MULTI-AGENT INFRASTRUCTURES FOR OBJECTIVE AND SUBJECTIVE COORDINATION

Coordination in multi-agented systems (MAS) can be conceived as either an agent activity (the subjective viewpoint) or an activity over agents (the objective viewpoint). The two viewpoints have generated two diverging and often contrasting lines of research, as well as different and noncompatible technologies, however, their integration is mandatory for modeling and engineering complex MAS. In this paper, we explore the issue of integration at both the model and the technology levels.

First, by taking FIPA agents and coordination artifacts as reference notions for subjective and objective approaches, respectively, we sketch a framework where agent interactions with coordination artifacts are modeled as physical acts, deliberated and executed by agents analogously to communicative actions. Then, we show how the JADE infrastructure for FIPA-compliant agents, and the TuCSoN infrastructure providing agents with coordination artifacts can be integrated at the technology level, allowing JADE agents to access TuCSoN tuple centers through JADE services.     

Proplant: Multiagent system for production planning

The so-called ''tribase'' acquaintance model of the agent's behavior is presented in this paper. This represents an extension of the twin-base model (Cao et al., 1997). Based on practical experience, the new model tries to cope with parallel processing, precedence constraints, and sparse resources. The idea of substituting the interagent negotiation processes by the periodical internal planning activity of the agents is stressed. A multiagent system, ProPlanT, as an application of the tribase model for the project-oriented production planning developed for TESLA TV company is described in detail. Three types of agents production planning agent (PPA), production management agent (PMA), and production agent (PA) are distinguished. The corresponding tribase models and potential role of metaagents are discussed.     

THE STROBE MODEL: DYNAMIC SERVICE GENERATION ON THE GRID

This article presents the STROBE model: both an agent representation and an agent communication, model based on a social approach, which means interaction centered. This model represents how agents may realize the interactive, dynamic generation of services on the Grid. Dynamically generated services embody a new concept of service implying a collaborative creation of knowledge, i.e., learning; services are constructed interactively between agents depending on a conversation. The approach consists of integrating selected features from multi-agent systems and agent communication, language interpretation in applicative/functional programming and e-learning/human-learning into a unique, original, and simple view that privileges interactions, including control. The main characteristic of STROBE agents is that they develop a language (environment + interpreter) for each of their interlocutors. The model is inscribed within a global approach, defending a shift from the classical algorithmic (control based) view to problem solving in computing to an interaction-based view of social informatics, where artificial as well as human agents operate by communicating as well as by computing. The paper shows how the model may not only account for the classical communicating agent approaches, but also represent a fundamental advance in modeling societies of agents in particular in dynamic service generation scenarios such as those necessary today on the Web and proposed tomorrow for the Grid. Preliminary concrete experimentations illustrate the potential of the model; they are significant examples for a very wide class of computational and learning situations.     

Testing robot controllers using constraint programming and continuous integration

ContextTesting complex industrial robots (CIRs) requires testing several interacting control systems. This is challenging, especially for robots performing process-intensive tasks such as painting or gluing, since their dedicated process control systems can be loosely coupled with the robot’s motion control.ObjectiveCurrent practices for validating CIRs involve manual test case design and execution. To reduce testing costs and improve quality assurance, a trend is to automate the generation of test cases. Our work aims to define a cost-effective automated testing technique to validate CIR control systems in an industrial context.MethodThis paper reports on a methodology, developed at ABB Robotics in collaboration with SIMULA, for the fully automated testing of CIRs control systems. Our approach draws on continuous integration principles and well-established constraint-based testing techniques. It is based on a novel constraint-based model for automatically generating test sequences where test sequences are both generated and executed as part of a continuous integration process.ResultsBy performing a detailed analysis of experimental results over a simplified version of our constraint model, we determine the most appropriate parameterization of the operational version of the constraint model. This version is now being deployed at ABB Robotics’s CIR testing facilities and used on a permanent basis. This paper presents the empirical results obtained when automatically generating test sequences for CIRs at ABB Robotics. In a real industrial setting, the results show that our methodology is not only able to detect reintroduced known faults, but also to spot completely new faults.ConclusionOur empirical evaluation shows that constraint-based testing is appropriate for automatically generating test sequences for CIRs and can be faithfully deployed in an industrial context.     

Using intentional fragments to bridge the gap between organizational and intentional levels

ContextBusiness process models provide a natural way to describe real-world processes to be supported by software-intensive systems. These models can be used to analyze processes in the system-as-is and describe potential improvements for the system-to-be. But, how well does a given business process model satisfy its business goals? How can different perspectives be integrated in order to describe an inter-organizational process?ObjectiveThe aim of the present paper is to link the local and the global perspectives of the inter-organizational business process defined in BPMN 2.0 (Business Process Model and Notation) to KAOS goal models (Keep All Objectives Satisfied). We maintain a separation of concerns between the intentional level captured by the goal model and the organizational level captured by the process model. The paper presents the concept of intentional fragment (a set of flow elements of the process with a common purpose) and assess its usefulness.MethodWe conducted empirical experiments where the proposed concepts – here the intentional fragments – are validated by users. Our method relies on an iterative improvement process led by users feedback.ResultsWe find that the concept of intentional fragment is useful for (1) analyzing the business process model (2) reasoning about the relations between the goal model and the business process model and (3) identifying new goals. In a previous work we focused on BPMN 2.0 collaboration models (local view). This paper extends the previous work by integrating the global view given by choreography models in the approach.ConclusionWe conclude that the notion of intentional fragment is a useful mean to relate business process models and goal models while dealing with their different nature (activity oriented vs goal oriented). Intentional fragments can also be used to analyze the process model and to infer new goals in an iterative manner.     

Semantic segmentation of trajectories with improved agent models for pedestrian behavior analysis

ABSTRACT

In this paper, we propose a method for semantic segmentation of pedestrian trajectories based on pedestrian behavior models, or agents. The agents model the dynamics of pedestrian movements in two-dimensional space using a linear dynamics model and common start and goal locations of trajectories. First, agent models are estimated from the trajectories obtained from image sequences. Our method is built on top of the Mixture model of Dynamic pedestrian Agents (MDA); however, the MDA's trajectory modeling and estimation are improved. Then, the trajectories are divided into semantically meaningful segments. The subsegments of a trajectory are modeled by applying a hidden Markov model using the estimated agent models. Experimental results with a real trajectory dataset show the effectiveness of the proposed method as compared to the well-known classical Ramer-Douglas-Peucker algorithm and also to the original MDA model.     

Drawing Trees Symmetrically in Three Dimensions

Abstract. Symmetric graph drawing enables a clear understanding of the structure of the graph. Previous work on symmetric graph drawing has focused on two dimensions. Symmetry in three dimensions is much richer than that of two dimensions. This is the first paper to extend symmetric graph drawing into three dimensions. More specifically, the paper investigates the problem of drawing trees symmetrically in three dimensions. First, we suggest a model for drawing trees symmetrically in three dimensions. Based on this model, we present a linear time algorithm for finding the maximum number of three-dimensional symmetries in trees. We also present a three-dimensional symmetric drawing algorithm for trees.     

Mobile Agent-Based Memory Tracer Using Host-Based Intrusion Detection System for Safeguarding Critical Memory

ABSTRACT

Intrusion in a host may cause damage to the critical memory, which contains important official files or databases. The mobile agent, a piece of code that makes parallel run on host, migrates through the network and performs the requested action. In this paper, we declare a new intrusion detection model using Host-Based Intrusion Detection System (HIDS) for identification and recovery strategies. A memory trace model has been designed to identify the intrusion detection by using a memory tracer mobile agent. Memory Checksum plays a vital role in the identification of the intrusion. This model is designed for intrusion into a host, which alters the critical memory.     

Automatic generation of communication and teamwork within multi-agent teams

Teamwork and communication are two important processes within multi-agent systems designed to act in a coherent and coordinated manner. Modeling teamwork involves interleaving steps within shared plans that will allow agents to work together towards common goals. These steps involve reasoning about roles, responsibilities, and joint-intentions in order to coordinate activity amongst individuals. Communication facilitates teamwork. There are various complex forms of communication such as synchronization, coordination, and cooperation that allow for members of teams to use teamwork to their advantage. Explicitly defining every possible communication point within a team plan is too cumbersome and inflexible. In this paper, we describe a method to automatically decompose a team plan into a collection of individual agent plans, inserting all of the necessary communication points needed to properly generate coordinated behavior. This approach could be used to more accurately and easily model teamwork in multi-agent systems.     

An Observation Approach to the Semantics of Agent Communication Languages

We show how a formal framework for the observation issue in computer systems can be used for the specification of an agent behavior, abstracting away from agent inner details while focusing on its interactive behavior. This model can also be used as a specification of agent communication languages (ACLs), providing the proper abstraction level to represent the conditions causing an agent to send a message, as well as its effect on the receiving agent. In particular, this approach generalizes upon existing ACL semantics, such as FIPA ACL, that relate agent communicative acts to the agent mental state. Since the observation framework induces a more abstract architecture than other known approaches, our semantics are likely to be applicable to a wider set of agent architectures, thus better supporting standardization aims. Some application examples are shown, describing how various aspects of ACL semantics can be specified within our framework.     

AGENT COORDINATION CONTEXTS IN A MAS COORDINATION INFRASTRUCTURE

In order to harness complexity in multi-agent systems (MAS), first-class entities that mediate interaction between agents and environment are required, which can encapsulate control over MAS behavior and evolution. To this end, MAS infrastructures should provide mediating artifacts, both enabling and constraining agent interactions, and possibly representing admissible agent perceptions and actions over the environment.

Along this line, in this paper, we take the notion of agent coordination context (ACC) as a means to model agent-environment interactions, and show how it can be embedded within a MAS infrastructure in terms of model and runtime structures. Then, we take the TuCSoN coordination infrastructure as a reference, and extend it with the ACC abstraction to integrate the support for coordination with organization and security.     

THE EMPATHIC COMPANION: A CHARACTER-BASED INTERFACE THAT ADDRESSES USERS' AFFECTIVE STATES

ABSTRACT

In this paper, we report on our efforts in developing affective character-based interfaces, i.e., interfaces that recognize and measure affective information of the user and address user affect by employing embodied characters. In particular, we describe the Empathic Companion, an animated interface agent that accompanies the user in the setting of a virtual job interview. This interface application takes physiological data (skin conductance and electromyography) of a user in realtime, interprets them as emotions, and addresses the user's affective states in the form of empathic feedback. The Empathic Companion is conceived as an educational agent that supports job seekers preparing for a job interview.

We also present results from an exploratory study that aims to evaluate the impact of the Empathic Companion by measuring users' skin conductance and heart rate. While an overall positive effect of the Empathic Companion could not be shown, the outcome of the experiment suggests that empathic feedback has a positive effect on the interviewee's stress level while hearing the interviewer question.     

Model checking agent programming languages

In this paper we describe a verification system for multi-agent programs. This is the first comprehensive approach to the verification of programs developed using programming languages based on the BDI (belief-desire-intention) model of agency. In particular, we have developed a specific layer of abstraction, sitting between the underlying verification system and the agent programming language, that maps the semantics of agent programs into the relevant model-checking framework. Crucially, this abstraction layer is both flexible and extensible; not only can a variety of different agent programming languages be implemented and verified, but even heterogeneous multi-agent programs can be captured semantically. In addition to describing this layer, and the semantic mapping inherent within it, we describe how the underlying model-checker is driven and how agent properties are checked. We also present several examples showing how the system can be used. As this is the first system of its kind, it is relatively slow, so we also indicate further work that needs to be tackled to improve performance.