Aspect-oriented interaction in multi-organisational web-based systems

Separation of concerns has been presented as a promising tool to tackle the design of complex systems in which cross-cutting properties that do not fit into the scope of a class must be satisfied. Unfortunately, current proposals assume that objects interact by means of object-oriented method calls, which implies that they embed interactions with others into their functional code. This makes them dependent on this interaction model, and makes it difficult to reuse them in a context in which another interaction model is more suited, e.g., tuple spaces, multiparty meetings, ports, and so forth. In this paper, we show that functionality can be described separately from the interaction model used, which helps enhance reusability of functional code and coordination patterns. Our proposal is innovative in that it is the first that achieves a clear separation between functionality and interaction in an aspect-oriented manner. In order to show that it is feasible, we adapted the multiparty interaction model to the context of multiorganisational web-based systems and developed a class framework to build business objects whose performance rates comparably to handmade implementations; the development time, however, decreases significantly.Comisión Interministerial de Ciencia y Tecnología TIC2000-1106-C02-0

Participation and goal achievement of multiparty collaborative systems dealing with complex problems: A natural experiment

Multiparty collaborative systems often deal with wicked sustainability challenges. Previous research has emphasized the important role of stakeholder representation and participation in comprehensive sustainability decisions. We report the results of an empirical test of the effect of stakeholder participation on systemic goal achievement and on multiparty dynamics in a natural experiment, using the results obtained through two simulations in which 44 professionals participated. In one of the simulations a ‘party exclusion dynamic’ evolved. As the two simulations had a similar baseline, the same number of participants distributed in a similar manner among seven stakeholder parties in each simulation, we could test the effect of stakeholder participation on goal achievement and systemic dynamics, using the other simulation as a comparison. Our results show that stakeholder exclusion prevents systemic goal achievement, disrupts collaboration and induces systemic powerlessness

Typing actors using behavioural types

The actor model of computation assists and disciplines the development of concurrent programs by forcing the software engineer to reason about high-level concurrency abstractions. While this leads to a better handling of concurrency-related issues, the model itself does not exclude erratic program behaviours. In this paper we consider the actor model and investigate a type-based static analysis to identify actor systems which may behave erraticly during runtime. We consider the notion of behavioural types and consider issues related to the nature of the actor model including non-determinism, multi-party communication, dynamic actor spawning, non-finite computation and a possibly changing communication topology, which we contrast with existing works.peer-reviewe

Collaboration and the Ecology of Democracy

This Kettering Foundation report explores the features and implications of citizen-driven, multi-party collaboration. Kettering has called the spaces and opportunities where this type of collaboration takes place the "political wetlands." Kemmis and McKinney embrace this ecological metaphor, seeing the emergence of democracy as similar to the self-organizing phenomena that arise in the natural realm. As democracy has evolved and matured over the millennia, it has become more bureaucratic and structured. Toward the end of the 20th century, citizens' desire for a more authentically engaged and constructive kind of involvement has produced new, less structured forms of deliberative and collaborative democracy.Several case studies of collaboration revolving around natural resources and governing public land are provided. In Idaho, for example, the Henry's Fork Watershed Council brings together competing interests -- farmers, ranchers, anglers, outfitters, guides, and environmentalists -- and provides a forum where they can address challenges that arise along the watershed. For nearly two decades, this group of people, who often stand on opposite sides of the political divide, has resolved problems by tapping into the collective intelligence of its members.The authors suggest that such place-based, collaborative initiatives may evolve into new forms of democratic governance

An order-based algorithm for implementing multiparty synchronization

Multiparty interactions are a powerful mechanism for coordinating several entities that need to cooperate in order to achieve a common goal. In this paper, we present an algorithm for implementing them that improves on previous results in that it does not require the whole set of entities or interactions to be known at compile- or run-time, and it can deal with both terminating and non-terminating systems. We also present a comprehensive simulation analysis that shows how sensitive to changes our algorithm is, and compare the results with well-known proposals by other authors. This study proves that our algorithm still performs comparably to other proposals in which the set of entities and interactions is known beforehand, but outperforms them in some situations that are clearly identified. In addition, these results prove that our algorithm can be combined with a technique called synchrony loosening without having an effect on efficiency.Ministerio de Ciencia y Tecnología TIC 2003-02737-C02-0