1. Preliminaries. Only bounded operators on a Hilbert space § of elements x will be considered. If A is self-ad joint with the spectral resolution (1) A=f\dE(k), and if ^a = £>aC4) denotes the set of elements x for which ||E(X)#|| is an absolutely continuous function of X, then § 0 is a subspace; cf. [2, p. 240], [3, p. 436] and [6, p. 104]. If £ = £«, then A is called absolutely continuous. Th...

We provide an axiomatization of expected equally-distributed equivalent-utility social welfare functions in the context of Harsanyi’s impartial observer theorem. For this family of social welfare functions, we show what additional axiom is necessary and suffi cient for the observer to exhibit aversion to ex post inequality. We also relate this axiomatization to our axiomatization in a companion...

Mobile smart devices and services have become an integral part of our daily life. In this context there are many compelling scenarios for mobile device users to share resources. A popular example is tethering. However, resource sharing also raises privacy and security concerns. In this paper, we present CrowdShare, a complete framework and its (Android) implementation for secure and private res...

Chat tools are nowadays an integral part of many collaborative e-learning environments. However, standard chat tools suffer from important coordination and coherence deficiencies. In this paper we propose an open source generic framework for building malleable structured chat applications. Users can strengthen or relax constraints when they want during a chat session. The paper shows some demon...

The increasing recognition that the study of human behaviors has to take into account the multiple contexts in which they occur has opened a promising research avenue in social sciences. It also presents new challenges, i.e. to complement micro-level surveys with the collection of meaningful contextual data within a common conceptual framework. The international comparative Generations and Gend...

Third-party services form an integral part of the mobile ecosystem: they allow app developers to add features such as performance analytics and social network integration, and to monetize their apps by enabling user tracking and targeted ad delivery. At present users, researchers, and regulators all have at best limited understanding of this third-party ecosystem. In this paper we seek to shrin...

It may seem self-evident that social welfare programs should regularly be assessed and refined in the light of lessons drawn from experience. Nevertheless, systematic program evaluation is a recent development. Modern evaluation practice is generally agreed to have begun in the middle 1960s, when initial attempts were made to evaluate programs enacted or proposed as part of the War on Poverty.'...

The establishment of desirable social norms is an integral part of a well-functioning civil society. While recent evidence has demonstrated that social comparison can affect behavior in a variety of contexts, it is not clear what type of comparative social information is most effective. Using a largescale field experiment to study driving practices, we sent text messages containing different ty...

How to answer a question? If the inquirer asks it in order to make a decision about something, then a wide range of reactions can be appropriate. If asked ‘Who of the applicants is qualified for the job?’, reactions may range from ‘Only Müller and Schmidt’, ‘At least Müller’, over ‘Müller has working experience in this field’, ‘Schmidt needs extra training’, to ‘The younger ones show more enthu...

It may seem self-evident that social welfare programs should regularly be assessed and refined in the light of lessons drawn from experience. Nevertheless, systematic program evaluation is a recent development. Modern evaluation practice is generally agreed to have begun in the middle 1960s, when initial attempts were made to evaluate programs enacted or proposed as part of the War on Poverty.'...