Characterization of trade-off preferences between non-functional properties

Efficient design and evolution of complex software intensive systems rely on the ability to make informed decisions as early as possible in the life cycle. Such informed decisions should take both the intended functional and non-functional properties into account. Especially regarding the latter, it is both necessary to be able to predict properties and to prioritize them according to well-defined criteria. In this paper we focus on the latter problem, that is to say how to make trade-offs between non-functional properties of software intensive systems. We provide an approach based on the elicitation of utility functions from stake-holders and subsequent checks for consistency among these functions. The approach is exploitable through an easy-to-use GUI, which is also presented. Moreover, we describe the setup and the outcome of our two-fold validation based on exploratory elicitations with students and practitioners

Diversification Preferences in the Theory of Choice

Diversification represents the idea of choosing variety over uniformity. Within the theory of choice, desirability of diversification is axiomatized as preference for a convex combination of choices that are equivalently ranked. This corresponds to the notion of risk aversion when one assumes the von-Neumann-Morgenstern expected utility model, but the equivalence fails to hold in other models. This paper studies axiomatizations of the concept of diversification and their relationship to the related notions of risk aversion and convex preferences within different choice theoretic models. Implications of these notions on portfolio choice are discussed. We cover model-independent diversification preferences, preferences within models of choice under risk, including expected utility theory and the more general rank-dependent expected utility theory, as well as models of choice under uncertainty axiomatized via Choquet expected utility theory. Remarks on interpretations of diversification preferences within models of behavioral choice are given in the conclusion

The effects of entry in thin markets

We consider entry of additional firms into the market for a single commodity in which both sellers and buyers are permitted to interact strategically. We show that the market is quasi-competitive, in that the inclusion of an additional seller lowers the price and increases the volume of trade, as expected. However, whilst buyers benefit from this change under reasonable conditions on preferences, we cannot conclude that sellers are always made worse off in the face of more intense competition, contrary to the conventional wisdom. We characterize the conditions under which entry by new sellers may raise the equilibrium profit of existing sellers, which will depend in an intuitive way on the elasticity of a strategic analog of demand and the market share of existing sellers, and encompass completely standard economic environments

INCENTIVE-COMPATIBLE AND EFFICIENT RESOURCE ALLOCATION IN LARGE ECONOMIES: AN EXACT AND LOCAL APPROACH

The main result of this paper characterizes possibly non-symmetric strategy-proof and efficienct choice functions as Perfectly Competitive. Efficiency is defined as impossibility of improvement by reallocation of commodity among finite sets of agents, and largeness of the economy is captured by a weak aggregation-condition called ""local separability."" Individual rationality constraints with respect to an assignment of endowments imply that the resulting allocations must be Walrasian relative to the assignment of endowments. The exact, local approach combined with a normality assumption on the domain of preferences allows the proofs to remain elementary throughout.

Apportioning of Risks via Stochastic Dominance

Consider a simple two-state risk with equal probabilities for the two states. In particular, assume that the random wealth variable Xi dominates Yi via ith-order stochastic dominance for i = M,N. We show that the 50-50 lottery [XN + YM, YN + XM] dominates the lottery [XN + XM, YN + YM] via (N + M)th-order stochastic dominance. The basic idea is that a decision maker exhibiting (N + M)th-order stochastic dominance preference will allocate the state-contingent lotteries in such a way as not to group the two "bad" lotteries in the same state, where "bad" is defined via ith-order stochastic dominance. In this way, we can extend and generalize existing results about risk attitudes. This lottery preference includes behavior exhibiting higher order risk effects, such as precautionary effects and tempering effects.downside risk, precautionary effects, prudence, risk apportionment, risk aversion, stochastic dominance, temperance

An axiomatic approach to sustainable development

The paper proposes two axioms that capture the idea of sustainable development and derives the welfare criterion that they imply. The axioms require that neither the present nor the future should play a dictatorial role. Theorem 1 shows there exist sustainable preferences, which satisfy these axioms. They exhibit sensitivity to the present and to the long-run future, and specify trade-offs between them. It examines other welfare criteria which are generally utilized: discounted utility, lim inf. long run averages, overtaking and catching-up criteria, Ramsey's criterion, Rawlsian rules, and the criterion of satisfaction of basic needs, and finds that none satisfies the axioms for sustainability. Theorem 2 gives a characterization of all continuous independent sustainable preferences. Theorem 3 shows that in general sustainable growth paths cannot be approximated by paths which approximate discounted optima. Proposition 1 shows that paths which maximize the present value under a standard price system may fail to reach optimal sustainable welfare levels, and Example 4 that the two criteria can give rise to different value systems.sustainable development; economic development; welfare

The effects of Entry in thin markets

We consider entry of additional firms into the market for a single commodity in which both sellers and buyers are permitted to interact strategically. We show that the market is quasi-competitive, in that the inclusion of an additional sellerlowers the price and increases the volume of trade, as expected. However, whilst buyers benefit from this change under reasonable conditions on preferences, we cannot conclude that sellers are always made worse off in the face of more intense competition, contrary to the conventional wisdom. We characterize the conditions under which entry by new sellers may raise the equilibrium profit of existing sellers, which will depend in an intuitive way on the elasticity of a strategic analog of demand and the market share of existing sellers, and encompass completely standard economic environments.bilateral oligopoly; entry; comparative statics.

Landscape Economics : The Road Ahead

The aims of this paper are to delineate some important topics in landscape economics, and also to take stock of the works and debates presented during the life of the CEEP project (from the first meeting in Angers (2006) , to the present one in Vienna). The objective of the research progamm initiated by the MEEDAT was to put landscape policy in the perspective of the sustainable development. The research issue is about the relationships between the development paths and landscape changes, paved with examples of consensus, controversies, and conflicts. This perspective was challenging for economists, due to the two gaps observed between the development of landscape research in geography, ecology or sociology and the absence of a corresponding corpus in economics, on one hand, and the development of landscape policies compared to the development of research in economics, on the other one. Precursors in landscape economics are certainly Von Thünen, who created the first model explaining the role of dispersing forces in the landscape making up, and C. Price, for the analysis of landscape preferences and the evaluation of landscape projects.[...]