104,992 research outputs found
A Methodology for Modelling Mobile Agent-Based Systems (Mobile agent Mobility Methodology - MaMM)
Mobile agents are a particular type of agents that have all the characteristics of
an agent and also demonstrate the ability to move or migrate from one node to
another in a network environment. Mobile agents have received considerable
attention from industry and the research community in recent times due to the
fact that their special characteristic of migration help address issues such as
network overload, network latency and protocol encapsulation. Due to the current
focus in exploiting agent technology mainly in a research environment, there has
been an influx of software engineering methodologies for developing multi-agent
systems. However, little attention has been given to modelling mobile agents. For
mobile agent-based systems to become more widely accepted there is a critical
need for a methodology to be developed to address various issues related to
modelling mobility of agent . This research study provides an overview of the
current approaches, methodologies and modelling languages that can be used
for developing multi-agent systems. The overview indicates extensive research
on methodologies for modelling multi-agent systems and little on mobility in
mobile agent-based systems. An original contribution in this research known as
Mobile agent-based Mobility Methodology (MaMM) is the methodology for
modelling mobility in mobile agent-based systems using underlying principles of
Genetic Algorithms (GA) with emphasis on fitness functions and genetic
representation. Delphi study and case studies were employed in carrying out this
research
Designing efficient intranet applications
Mobile agents are a quite new and interesting paradigm for the implementation of distributed systems. As with most distributed systems, mobile agent applications are usually developed and installed without regarding performance aspects. Typically, methods and tools for capacity planning differ fundamentally from methods and tools for system development, thus system developers often avoid additional modelling and planning effort. This dissertation helps to solve this problem by presenting an approach to easy integrate performance modelling into the development process of mobile agent applications. Most mobile agent applications contain the same basic scenarios, which include stationary agents with the role of servers and mobile agents as clients. Based on these scenarios, this dissertation describes a new modelling approach and a methodology for capacity planning of mobile agent systems with an emphasis on intranet applications. The core idea of the new modelling approach is to directly integrate byte code of real agents in a simulation environment. Thus, it is not necessary to describe agents’ behaviour on a high abstraction level. Their behaviour results from their program code. To build performance models, a system developer mainly has to specify the infrastructure of the mobile agent system and parameters for time consumption. Moreover, this dissertation focuses on providing algorithms to increase the efficiency of simulation models of mobile agent systems. As existing approaches are not applicable to the presented modelling technique, new methods are developed which consider special features of mobile agent systems and which regard the objectives of this dissertation. A methodology for capacity planning of general heterogeneous IT systems is adjusted to mobile agent systems according to the developed modelling techniques. The modelling concepts and the methodology for capacity planning are first presented and explained. They are implemented using the mobile agent platform Tracy1 and the simulation package JavaDEMOS2. Finally, the applicability of these approaches are demonstrated by a realistic case study
An Evaluation of Current Approaches for Modelling Mobility of Agents
The development of agent-based systems requires methodologies and modelling languages that are based on agent related concepts. Towards this direction, research has proposed a large number of Agent Oriented Software Engineering (AOSE) approaches to modelling mobility of agents. This paper will evaluate the current approaches and methodologies with respect to modelling mobile agent systems and it will propose a number of concepts required to adequately model agent mobility
Modelling the GSM handover protocol in CommUnity
CommUnity is a formal approach to software architecture. It has a precise, yet intuitive mathematical semantics based on category theory. It supports, at the methodological level, a clear separation between computation, coordination, and distribution (including mobility). It provides a simple state-based language for describing component behaviour that is inspired by Unity and Interacting Processes. It also addresses composition as a first class concern and accounts for the emergence of global system properties from interconnections. This paper describes the approach and available tool support by modelling essential aspects of the GSM handover protocol. We also sketch a framework that we are implementing for the distributed execution of such specifications using Klava, a Java library for mobile agent systems based on tuple spaces
Contemporary Robotics
This book book is a collection of 18 chapters written by internationally recognized experts and well-known professionals of the field. Chapters contribute to diverse facets of contemporary robotics and autonomous systems. The volume is organized in four thematic parts according to the main subjects, regarding the recent advances in the contemporary robotics. The first thematic topics of the book are devoted to the theoretical issues. This includes development of algorithms for automatic trajectory generation using redudancy resolution scheme, intelligent algorithms for robotic grasping, modelling approach for reactive mode handling of flexible manufacturing and design of an advanced controller for robot manipulators. The second part of the book deals with different aspects of robot calibration and sensing. This includes a geometric and treshold calibration of a multiple robotic line-vision system, robot-based inline 2D/3D quality monitoring using picture-giving and laser triangulation, and a study on prospective polymer composite materials for flexible tactile sensors. The third part addresses issues of mobile robots and multi-agent systems, including SLAM of mobile robots based on fusion of odometry and visual data, configuration of a localization system by a team of mobile robots, development of generic real-time motion controller for differential mobile robots, control of fuel cells of mobile robots, modelling of omni-directional wheeled-based robots, building of hunter- hybrid tracking environment, as well as design of a cooperative control in distributed population-based multi-agent approach. The fourth part presents recent approaches and results in humanoid and bioinspirative robotics. It deals with design of adaptive control of anthropomorphic biped gait, building of dynamic-based simulation for humanoid robot walking, building controller for perceptual motor control dynamics of humans and biomimetic approach to control mechatronic structure using smart materials
Multi-agent system security for mobile communication
This thesis investigates security in multi-agent systems for mobile communication.
Mobile as well as non-mobile agent technology is addressed.
A general security analysis based on properties of agents and multi-agent systems
is presented along with an overview of security measures applicable to
multi-agent systems, and in particular to mobile agent systems.
A security architecture, designed for deployment of agent technology in a mobile
communication environment, is presented. The security architecture allows
modelling of interactions at all levels within a mobile communication system.
This architecture is used as the basis for describing security services and mechanisms
for a multi-agent system. It is shown how security mechanisms can be
used in an agent system, with emphasis on secure agent communication.
Mobile agents are vulnerable to attacks from the hosts on which they are executing.
Two methods for dealing with threats posed by malicious hosts to a
trading agent are presented. The rst approach uses a threshold scheme and
multiple mobile agents to minimise the eect of malicious hosts. The second
introduces trusted nodes into the infrastructure.
Undetachable signatures have been proposed as a way to limit the damage a
malicious host can do by misusing a signature key carried by a mobile agent.
This thesis proposes an alternative scheme based on conventional signatures and
public key certicates.
Threshold signatures can be used in a mobile agent scenario to spread the risk
between several agents and thereby overcome the threats posed by individual
malicious hosts. An alternative to threshold signatures, based on conventional
signatures, achieving comparable security guarantees with potential practical
advantages compared to a threshold scheme is proposed in this thesis.
Undetachable signatures and threshold signatures are both concepts applicable
to mobile agents. This thesis proposes a technique combining the two schemes
to achieve undetachable threshold signatures.
This thesis denes the concept of certicate translation, which allows an agent
to have one certicate translated into another format if so required, and thereby
save storage space as well as being able to cope with a certicate format not
foreseen at the time the agent was created
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Agent based modelling and simulation: An examination of customer retention in the UK mobile market
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Customer retention is an important issue for any business, especially in mature markets such as the UK mobile market where new customers can only be acquired from competitors. Different methods and techniques have been used to investigate customer retention including statistical methods and data mining. However, due to the increasing complexity of the mobile market, the effectiveness of these techniques is questionable. This study proposes Agent-Based Modelling and Simulation (ABMS) as a novel approach to investigate customer retention. ABMS is an emerging means of simulating behaviour and examining behavioural consequences. In outline, agents represent customers and agent relationships represent processes of agent interaction. This study follows the design science paradigm to build and evaluate a generic, reusable, agent-based (CubSim) model to examine the factors affecting customer retention based on data extracted from a UK mobile operator. Based on these data, two data mining models are built to gain a better understanding of the problem domain and to identify the main limitations of data mining. This is followed by two interrelated development cycles: (1) Build the CubSim model, starting with modelling customer interaction with the market, including interaction with the service provider and other competing operators in the market; and (2) Extend the CubSim model by incorporating interaction among customers. The key contribution of this study lies in using ABMS to identify and model the key factors that affect customer retention simultaneously and jointly. In this manner, the CubSim model is better suited to account for the dynamics of customer churn behaviour in the UK mobile market than all other existing models. Another important contribution of this study is that it provides an empirical, actionable insight on customer retention. In particular, and most interestingly, the experimental results show that applying a mixed customer retention strategy targeting both high value customers and customers with a large personal network outperforms the traditional customer retention strategies, which focuses only on the customer‘s value.This work is funded by the Brunel Department of Information Systems and Computing (DISC
A framework for implementing formally verified resource-bounded smart space systems
© 2017, Springer Science+Business Media New York. Context-aware computing is a mobile computing paradigm that helps designing and implementing next generation smart applications, where personalized devices interact with users in smart environments. Development of such applications is inherently complex due to these applications adapt to changing contextual information and they often run on resource-bounded devices. Most of the existing context-aware development frameworks are centralized, adopt client–server architecture, and do not consider resource limitations of context-aware devices. This paper presents a systematic framework to modelling and implementation of resource-bounded multi-agent context-aware systems on Android devices. The proposed framework makes use of semantic technologies for context modelling and reasoning about resource-bounded context-aware agents, Android powered smartphones as development platform, a suitable communication model and declarative rule-based programming as a preferred development language
Modelling and Simulation of Urban Mobile Agents for Analyzing Mixed Flows in Urban Pedestrian Space
Since the 1990s, complex systems research has been developing agent simulations to explain the phenomena observed in urban spaces. In recent years, agent-based modelling has often been employed to successfully simulate pedestrian behaviour. In such studies, explanations using pedestrian counter flow phases have appeared sporadically. Most state-of-the-art models, however, do not generally consider mobile agents other than pedestrians or counter flows in at least two directions. In this paper, we consider agents such as pedestrians, vehicles, wheelchairs, bicycles and so on in urban pedestrian space (UPS), which we call urban mobile agents (UMAs). The aim of this research is to develop a simulation platform to support urban simulation research. The models of rule-based UMAs that we have been developing are used to analyze the micro-meso behaviours of the mixed flows in UPS. The content of this class of agent includes the pedestrian agent as per the simplified agent simulation of pedestrian flow (sASPF) rules as well as the vehicle agent and bicycle agent in the UPS, including a wheelchair agent in the coming research. Using these models, we explore the following approaches: (a) theoretical analyses of phase transitions such as laminar flow formation or blockade of pedestrian counter flows, with clarification of the relationship between the degree of pedestrian global density and the bias of the diagonal stepping probability, which is the right or left selection probability of avoidance behaviour; (b) the implementation of obstacle avoidance rules in the sASPF pedestrian agent model, and their comparison with published evacuation experiment results, so as to evaluate the performance of the obstacle avoidance function; (c) the development of a vehicle agent model to simulate pedestrian-vehicle mixed flow at a crossroads assuming a disaster scenario; (d) the development of a bicycle agent model by extending sASPF rules; and (e) consideration of a conceptual framework for interaction fields representing heterogeneous agent mixed flows, including vehicle, bicycle, pedestrian and wheelchair agents
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