14915210
A Framework for Model-Based Design of Agent-Oriented Software
Agents are becoming one of the most important topics in distributed and autonomous decentralized systems, and there are increasing attempts to use agent technologies to develop large-scale commercial and industrial software systems. The complexity of such systems suggests a pressing need for system modeling techniques to support reliable, maintainable, and extensible design. G-nets are a type of Petri net defined to support system modeling in terms of a set of independent and loosely-coupled modules. In this paper, we customize the basic G-net model to define a so-called "agent-based G-net" that can serve as a generic model for agent design. Then, to progress from an agent-based design model to an agent-oriented model, new mechanisms to support inheritance modeling are introduced. To illustrate our formal modeling technique for multiagent systems, an example of an agent family in electronic commerce is provided. Finally, we demonstrate how we can use model checking to verify some key behavioral properties of our agent model. This is facilitated by the use of an existing Petri net tool.
5913002
Formal modeling of synchronization methods for concurrent objects in Ada 95
One important role for Ada programming is to aid engineering of concurrent and distributed software. In a concurrent and distributed environment, objects may execute concurrently and need to be synchronized to serve a common goal. Three basic methods by which objects in a concurrent environment can be constructed and synchronized have been identified [1]. To formalize the semantics of these methods and to provide a formal model of their core behavior, we provide some graphic models based on the Petri net formalism. The purpose of this formal modeling is to illustrate the possibility of automatic program analysis for object-oriented features in Ada-95. Models for the three distributed- object synchronization methods are discussed, and a potential deadlock situation for one of the methods/models is illustrated. We conclude with some comparison of the three methods in terms of the model abstractions.
4691280
A Methodology for Role-Based Modeling of Open Multi-Agent Software Systems
Multi-agent systems (MAS) are rapidly emerging as a powerful paradigm for modeling and developing distributed information systems. In an open multi-agent system, agents can not only join or leave an agent society at will, but also take or release roles dynamically. Most of existing work on MAS uses role modeling for system analysis; however, role models are only used at conceptual level with no realizations in the implemented system. In this paper, we propose a methodology for role-based modeling of open multiagent software systems. We specify role organization and role space as containers of conceptual roles and role instances, respectively. Agents in an agent society can take or release roles from a role space dynamically. The relationships between agents are deduced through a mechanism called A-R mapping. As a potential solution for automated MAS development, we summarize the procedures to generate a role-based design of open multi-agent software systems.
9774737
A framework for modeling agent-oriented software
With the increasing importance of complex software systems in the software industry, the need for using agent technologies to develop large-scale commercial and industrial software systems is growing rapidly. Such systems are complex, and there is a pressing need for system modeling techniques to support reliable, maintainable and extensible design. G-nets are a type of Petri net defined to support the modeling of a system as a set of independent and loosely-coupled modules. In this paper, we first introduce an extension of G-nets - the agent-based G-net - as a generic model for agent design. Then, to progress from an agent-based design model to an agent-oriented model, new mechanisms to support inheritance modeling are introduced. To illustrate our formal modeling technique for multi-agent systems, an example of an agent family in electronic commerce is provided.
18614429
A petri net based XML firewall security model for web services invocation
An XML firewall differs from a conventional firewall because its major task is to control access to web services rather than to filter untrusted addresses. An XML firewall can effectively protect web services from being attacked by inspecting a complete XML message including its head and data segments, and rejecting unauthorized web services invocation. In this paper, we propose a formal XML firewall security model using role-based access control (RBAC). Our proposed model supports user authentication and user authorization according to information stored in a user database and a policy database associated with an XML firewall. The formal model is designed compositionally using Petri nets, which can serve as a high-level design for XML firewall implementation. The key components of our compositional security model are the application model and the XML firewall model. To illustrate the advantages of our formal approach, we use an existing Petri net tool to verify some key properties of our model, such as boundedness and liveness.
7136406
Towards Automated Development of Multi-Agent Systems Using RADE
To facilitate the development of multi-agent systems and improve the reusability, robustness and feasibility of these systems, we proposed a role-based agent development framework (RADE). In this paper, we present more details on the design of agents and motivations within such framework. We introduce a practical approach to modeling agent’s motivation and specifying agent’s goals, where a role-mapping mechanism is developed based on this design. We also introduce the RTAEMS language based on the extension of TAEMS to model the plan tree for each goal. This representation is used to support the development of general planning/scheduling and collaboration/cooperation mechanisms.
34350964
Efficient Representation of Spectral BRDFs
28938007
A novel carrier frequency tracking scheme for time domain differential OFDM
We develop a novel scheme to track carrier frequency offset in time domain differential modulation and demodulation OFDM systems. Compared with existing methods, this scheme is more bandwidth efficient and easier to implement. Simulation results in the Rayleigh fading channel show that this frequency tracking scheme can work robustly under relatively low SNR conditions.
9140729
INSPIRE: an interactive image assisted non-photorealistic rendering system
We present a GPU supported interactive non-photorealistic rendering system, INSPIRE, which performs feature extraction in both image space, on intermediately rendered images, and object space, on models of various representations, e.g., point, polygon, or hybrid models, without needing connectivity information. INSPIRE obtains interactive NPR rendering with most styles of existing NPR systems, but offers more flexibility on model representations and compromises little on rendering speed.
4864247
Data processing and compact representation of measured isotropic spectral BRDF
This paper presents the methods for both data processing and compact representation of measured isotropic spectral BRDF. For the data processing, we develop a numerical method for filtering the noises, re-sampling the data from non-uniform sampling to uniform sampling, and interpolation. For the compact representation, we propose a method to represent the spectral BRDF in both the spectral and spatial domains. In spectral domain, for each pair of the incident and outgoing directions, we represent the spectral BRDF with Fourier coefficients. In spatial domain, for all the outgoing directions of a given incident direction, we represent the same-order Fourier coefficients either directly using a linear combination of spherical harmonics or a linear combination of spherical harmonics and a Gaussian, depending on their angular dependencies. Three Gaussian expressions are presented. Numerical studies are given for a measured isotropic spectral BRDF.
16644843
Alleviating Consumers' Privacy Concerns in Location-Based Services: A Psychological Control Perspective
Location-based services (LBS), enabled by advances in mobile and positioning technologies, have afforded users with a pervasive flexibility to be uniquely addressable and to access network and services on-the-move. However, because LBS could also associate the lifestyle habits, behaviors, and movements with a consumer’s personal identity, privacy concerns are particularly salient for LBS. Drawing on psychological control and privacy literature, we designed an experiment study to test the basic proposition that the assurance of consumers’ perceived control over their personal information has a considerable influence on alleviating their privacy concerns. Three different mechanisms of assurance of control—technology, industry self-regulation, and legislation—were manipulated in the experiment, and their effects on consumers’ privacy concerns were examined. The results indicated that the technological assurance mechanism (i.e., mobile device in this study) played the most important role in assuring consumers’ perceived control over personal information. The marriage of the privacy and psychological control literature streams provides a rich understanding of consumers’ privacy reaction to LBS usage and, therefore, benefits the privacy and human-computer interaction (HCI) research in the Information Systems discipline.