39578766
On the Quantitative Assessment of Modular Multi-Agent Architectures
979214
Enhancing agent-oriented models with aspects
The modular representation of concerns is imperative in the design modeling of multi-agent systems (MASs). However, MAS designers typically face a number of concerns that inherently affect several system agents and their respective internal elements, such as actions and goals. These crosscutting concerns encompass both internal and systemic properties, such as learning, mobility, error handling, and security. Without an explicit modeling of such MAS properties, designers can not properly communicate and reason about them and their broadly-scoped effects. The result is a multitude of agent-oriented design breakdowns: poor traceability from requirements to design models, hindering of reuse opportunities, and decreased evolvability. This paper presents an enhancement of an existing agent-oriented modeling language with aspects. We illustrate the use of our approach through some classical examples of crosscutting concerns in agent-oriented design models.
9474173
Improving modularity of reflective middleware with aspect-oriented programming
Reflective middleware has been proposed as an effective way to enhance adaptability of component-oriented middleware architectures. To be effectively adaptable, the implementation of reflective middleware needs to be modular. However, some recently emerged applications such as mobile, pervasive, and embedded applications have imposed more stringent modularity requirements to the middleware design. They require support for the conception of a minimal middleware while promoting finegrained modularity of reflective middleware features. The key problem is that fundamental mechanisms for decomposing reflective middleware implementations, such as object-oriented ones, suffer from not providing the proper means to achieve the required level of localizing reflection-specific concerns. This paper presents a systematic investigation on how aspect-oriented programming scales up to improve modularity of typical reflection-specific crosscutting concerns. We have quantitatively compared Java and AspectJ implementations of an OpenORB-compliant reflective middleware using separation of concerns metrics.
12082403
Improving Extensibility of Object-Oriented Frameworks with Aspect-Oriented Programming
Object-oriented frameworks are nowadays a common and useful technology used in the implementation of software system families. Despite their benefits, over the last years many researchers have described the inadequacy of object-oriented mechanisms to address the modularization and composition of many framework features, thus reducing the extent to which a framework can be extended. The crosscutting nature of many framework features is identified as one of the main causes of these problems. In this paper, we analyze how aspect-oriented programming can help to improve the design, implementation, and extension of object-oriented frameworks. We propose the concept of Extension Join Points (EJPs) as a way of designing and documenting existing crosscutting extension points. EJPs improve framework extensibility, including superior composability of the framework core functionality with other modules or frameworks. Four case studies of frameworks from diverse domains are presented to illustrate our proposal. This paper also discusses lessons learned on the application of our approach to the development and extension of these frameworks.
45365979
Software Engineering for Multi-Agent Systems
5202352
Taming Agents and Objects in Software Engineering
Agent-based software engineering has been proposed in addition to object-oriented software engineering as a means of mastering the complexity associated with the development of large-scale distributed systems. However, there is still a poor understanding of the interplay between the notions of agents and objects from a software engineering perspective. Moreover, the many facets of agent-based software engineering are rarely used in the various phases of the software development lifecycle because of the lack of a comprehensive framework to provide the software designers with a clear understanding of the use of these two key abstractions. In this context, this paper presents TAO, an evolving innovative conceptual framework based on agent and object abstractions, which are the foundations for modeling large-scale software systems. The conceptual framework allows for the characterization of large-scale software systems as organizations of passive components, the objects, and autonomous components, the agents, with each of these elements playing roles to interact with each other and to coordinate their actions in order to fulfill system goals.
17377991
Applying the HYRIWYG incentive mechanism in a recommender system
The use of recommender systems (RS) has become common in several e-commerce Web sites. Collaborative filtering is one of the most popular RS techniques. It infers a user's predilections based on similarity with other users. However, to work correctly, the RS depends on the evaluator's participation with truly opinions. The HYRIWYG mechanism proposes an incentive model to motivate users to contribute with a high number of opinions and, more important, guaranteeing the truthfulness of the information. In this paper, we present HYRIWYG mechanism and discuss it using an empirical study in the movie evaluation domain. Initial results highlight the great potential benefits of using this kind of incentive mechanism.
44575256
An X-Ray of the Brazilian e-Gov Web Sites
The digital inclusion promotes the reduction of social inequalities. Based on this principle, the Brazilian Government has been setting up an increasing number of Web access locations to render virtual support to its citizens. However, there are no guidelines for the construction and assessment of these electronic Government (e-Gov) sites. In this article we measure the web site quality in the e-Gov domain with the following proprieties: usability, accessibility, interoperability, security, privacy, information reliability, and service agility. We implemented our method, by using a checklist tool, in the evaluation of 127 Brazilian government sites (federal, state and municipal). Our method proved itself efficient in the diagnosis and identification of specific problems in the e-Gov site domain.
15357706
Modeling flow around a microrotor in creeping flow using a quasi-steady-state analysis
Paramagnetic microsphere suspensions placed in a rotating magnetic field aggregate to form rotating magnetic chains. These chains that are several tens of micrometers in length act as microrotors, and can be modeled as circular cylinders. The flow and associated micromixing around these cylinders rotating about their radial axis is studied for a very low Reynolds number, creeping-flow system.. Time-scales for momentum transfer are much smaller than boundary movement, hence a quasi-steady approximation can be used. The flow is derived at every instant from the case of a steady motion of a horizontally translating cylinder, with the rotation approximated to a series of incremental translations. A numerical simulation was used to determine the pathlines and material lines of point fluid elements, which were analyzed to understand the behavior of the microfluidic system. The results indicate the flow to be unsteady, with chaotic advection observed in the system. The flow is primarily two-dimensional with planar fluid movement limited to the immediate area around the rotating cylinder, with a small disturbance in the axial direction that is experienced up to many diameters away. Elliptic and star shaped pathlines, including periodic orbits, are observed depending on the fluid element's initial location. The trajectories and phase angles compare well with the limited experimental results, as well as with data from particle dynamics simulations. Material lines and streaklines display stretching and folding, which are indicative of the chaotic behavior of the system. The material lines have similar lengths for the same amount of rotation at different speeds, and the affect of rotational speeds appears to be primarily to change the time of mixing.
29246421
Sharing design perspectives through storytelling
Design consists of analyzing scenarios and proposing artifacts, obeying the initial set of requirements that lead from initial to goal state. Finding or creating alternative solutions, analyzing them, and selecting the best one are expected steps in the designer’s decision making process. Very often, not a sole designer, but a team of them is engaged in the design process, sharing their expertise and responsibility to achieve optimum projects. In a design team, most conflicts occur due to misunderstanding of one’s assessment of specifications and contexts. Decision explanations play a key role in teamwork success. Designers are rational agents trained to follow rational methods. Acceptable justifications include value function, requirements, constraints, and criteria. Generally, explanations are delivered in a multimedia fashion, composed of text, graphics and gestures, to provide the audience the ability to perceive what was contextually imagined. The more spatial the reasoning is, the richer the explanation channel should be. This paper presents CineADD, a design explanation generation model based on cinema techniques such as animation, scripting, editing, and camera movements. The idea is to provide designers with a tool for describing the way their projects should be visually explained, as in a movie. Designers develop their projects in an active design document environment. Rationale is captured as a design model, so explanations can be generated instead of retrieved. The captured design model serves as a base to visually reconstruct design, giving emphasis and guidance by using movie storytelling techniques. CineADD was implemented for the domain of oil pipeline layout showing the feasibility of this approach. We expect CineADD to become a commodity attachable to any intelligent CAD system.
6083238
A Multiagent System Applied to the Design of Petroleum Off-Shore Platforms
This paper presents a model for cooperative multi-agents that interact in a closed environment, i.e., an environment where the rules are well known by the agents and do not change dynamically. In a computational environment where several different software agents share resources to reach their goals, the occurrence of conflicts is inevitable. Therefore it is of highest importance to have an efficient mechanism to solve such conflicts. While other models in the literature present solutions for conflict resolution based on centralized and distributed algorithms, our proposal is to solve the conflicts in a hierarchical manner. The proposed model is based on the application of Social Laws and it was inspired by the theory of Jean Jacques Rousseau’s Social Contract, being denominated Tri-Coord Model, that is, of Triple Coordination. We implemented a prototype based on the Tri-Coord Model, and applied to the task of oil and gas process floorplan design in a petroleum off-shore platform. In that domain the project is divided in several subsystems, with an agent being responsible for each sub-system. Our experiments indicate that the Tri-Coord Model can indeed yield a better performance in the development of a project. First, because it decreases the interruptions for accomplishment of meetings to solve conflicts related to customization of sub-system’s parameters. Second, because it removes the bottleneck associated to a centralized model for conflict resolution. Third, because through the regulator environment of Tri-Coord the agents behavior can be controlled implicitly by the environment. In that way the agents learn how to interact correctly and the independence between the environment and the agents turns the system more flexible.