Abstract

Abstract
Existing bidirectional languages are either state-based or operation-based, depending on whether they represent updates as mere states or as sequences of edit operations. In-between both worlds are delta-based frameworks, where updates are represented using alignment relationships between states. In this paper, we formalize delta lenses over inductive types using dependent type theory and develop a point-free delta lens language with an explicit separation of shape and data. In contrast with the already known issue of data alignment, we identify the new problem of shape alignment and solve it by lifting standard recursion patterns such as folds and unfolds to delta lenses that use alignment to infer meaningful shape updates. © Bidirectional Transformations 2012.

Abstract

Abstract
This paper presents a formal framework in which to study the socialization processes evolving among utility-based agents. These agents are self-interested, being their different social attitudes (cooperativeness, competitiveness or indifference) a consequence of this behavior. The dynamics of the socialization process are captured by a relation that measures the similarities between the desires of two groups of agents. This similitude relation is derived from the system's model, defined as a probabilistic transition system and a set of individual preference relations. Game-theoretic concepts are used in order to determine the rational(or expected) transitions of the system. © 1998 IEEE.

Abstract
This paper is concerned with the formalization of a automated contracting mechanism that enables a society of cooperative resource allocation agents to negotiate rationally in a self-interested meta-society. Such environments induce agents to adopt different social behaviors according to the negotiation partner. This problem may be solved by taking an economic perspective in all the decisions, namely, by using utility based agents, through the use of marginal utility calculations, and defining dynamically the market extent for a task. The risk attitude and reactivity of each agent can be parameterized in order to achieve different negotiation strategies. The framework presented in this paper can be applied in a wide variety of situations, ranging from electronic commerce on virtual economic markets, to load distribution problems. © Springer-Verlag Berlin Heidelberg 1997.

Abstract
The calculus of relations has been widely used in program specification and reasoning. It is very tempting to use such specifications as running prototypes of the desired program, but, even considering finite domains, the inherent partiality and non-determinism of relations makes this impractical and highly inefficient. To tame partiality we prescribe the usage of invariants, represented by coreflexives, to characterize the exact domains and codomains of relational specifications. Such invariants can be used as pre-condition checkers to avoid runtime errors. Moreover, we show how such invariants can be used to narrow the non-deterministic execution of relational specifications, making it viable for a relevant class of problems. In particular, we show how the proposed techniques can be applied to execute specifications of bidirectional transformations, a domain where partiality and non-determinism are paramount. © 2012 Springer-Verlag.