205925700
Compositional Petri net models of advanced tasking in Ada-95
The Ada language has been designed to support development of concurrent and distributed software. While the Ada-83 standard defined the basic mechanisms of rendezvous-based tasking, the Ada-95 standard significantly extended this capability with the introduction of several advanced tasking constructs. We present and discuss formal models of these key tasking constructs using the Petri net model. We also provide some formal evaluation of the models using one particular net-based method, invariant analysis. The constructs considered are the asynchronous transfer of control, the protected object, and the requeue statement. By modeling these advanced Ada tasking constructs with Petri nets, we obtain compositional models of the constructs that are complementary to earlier work in net-based modeling of Ada tasking, both in terms of defining precise behavior for tasking semantics, and also in terms of providing support for automated analysis of concurrent software.
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.
22135026
A Security Based Model for Mobile Agent Software Systems
Security modeling for agents has been one of the most challenging issues in developing practical mobile agent software systems. In the past, researchers have developed mobile agent systems with emphasis either on protecting mobile agents from malicious hosts or protecting hosts from malicious agents. In this paper, we propose a security based mobile agent system architecture that provides a general solution to protecting both mobile agents and agent hosts in terms of agent communication and agent migration. We present a facilitator agent model that serves as a middleware for secure agent communication and agent migration. The facilitator agent model, as well as the mobile agent model, is based on agent-oriented G-nets — a high level Petri net formalism. To illustrate our formal modeling technique for mobile agent systems, we provide an example of agent migration to show how a design error can be detected.
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.
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.
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.
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.
7970424
Effects of Multimedia on Mobile Consumer Behavior: An Empirical Study of Location-Aware Advertising
Location-aware advertising is widely touted as the “killer-app” for mobile commerce to flourish. With the imminent rollout of third-generation mobile networks, advances in multimedia-enabled mobile devices and positioning technologies, its commercial viability is enormous. Location-aware advertising is primarily textbased at the present, but it is envisioned to allow the delivery of multimedia advertisements to geographically targeted consumers. This exploratory study empirically examines the effects of multimedia on consumer behavior in a simulated mobile commerce environment. A structural model was formulated to test the effects of multimedia on entertainment, informativeness, and irritation in the context of location-aware advertising. The results show that multimedia location-aware advertising messages lead to more favorable attitudes and increase the intention to reuse the mobile advertising service. Evidence also suggests that multimedia has a significant impact on purchase behavior.
10887257
Foundations of SMS commerce success: lessons from SMS messaging and co-opetition
As a convenient and low-cost mobile communication technology, short messaging service (SMS) is experiencing very rapid growth. It is reported that 700 million mobile phone users worldwide sent 20 to 30 billion SMS messages every month in 2001. At the same time, SMS commerce applications have emerged to provide mobile users consumer-oriented services. The huge SMS messaging customer base serves as the potential SMS commerce customer base according to K. Kellett and A. Linde (2001) . However, the bloom in messaging business does not automatically lead to the success of general SMS commerce applications. In this paper, we analyzed SMS developments in three different countries to derive three success indicators for SMS messaging and relate them to the success of SMS commerce. Based on the proposed SMS application framework, we postulate four additional hypothesized success factors that could uniquely contribute to the success of SMS commerce. Our findings provide practical implications for promoting SMS commerce applications successfully.
10910603
Hybrid Forward Resampling and Volume Rendering
The transforming and rendering of discrete objects, such as traditional images (with or without depths) and volumes, can be considered as resampling problem – objects are reconstructed, transformed, filtered, and finally sampled on the screen grids. In resampling practices, discrete samples (pixels, voxels) can be considered either as infinitesimal sample points (simply called points) or samples of a certain size (splats). Resampling can also be done either forwards or backwards in either the source domain or the target domain. In this paper, we present a framework that features hybrid forward resampling for discrete rendering. Specifically, we apply this framework to enhance volumetric splatting. In this approach, minified voxels are taken simply as points filtered in screen space; while magnified voxels are taken as spherical splats. In addition, we develop two techniques for performing accurate and efficient perspective splatting. The first one is to efficiently compute the 2D elliptical geometry of perspectively projected splats; the second one is to achieve accurate perspective reconstruction filter. The results of our experiments demonstrate both the effectiveness of antialiasing and the efficiency of rendering using this
15979413
Consumers' Privacy Concerns toward Using Location-Based Services: An Exploratory Framework and Research Proposal
Privacy concerns associated with the use of Location-Based Services (LBS) may ultimately prevent consumers from gaining the ‘anytime anywhere’ convenience. Through a psychological control lens, we examine whether individual difference variables such as locus of control (LOC) could have moderating effects on the relationship between privacy concern and three privacy assurance mechanisms in the LBS context. The paper develops a preliminary research model which conceptualizes the moderating effects of LOC by extending Xu and Teo (2004)’s research model. With an explicit focus on LOC, this study will not only add an important piece of information to our understanding of consumers’ reactions to LBS but also can help frame the ongoing policy and scholarly debate surrounding the relative effectiveness of technology, industry self-regulation and government legislation in ensuring consumers’ privacy. We believe that our findings will be able to offer practical implications for the various players in the LBS landscape: merchants, wireless service providers, wireless device manufacturer, privacy advocates and legislators.