Articles

Microcomputations as Micropayments in Web-based Services

G. O. KARAME, A. FRANCILLON, V. BUDILIVSCHI, S. CAPKUN, V. CAPKUN

ACM Transactions on Internet Technology

mai 2014, vol. 13, n°3

Départements : Comptabilité et Contrôle de Gestion, GREGHEC (CNRS)

http://dl.acm.org/citation.cfm?id=2611526&dl=ACM&coll=DL&CFID=790735117&CFTOKEN=32190012


In this article, we propose a new micropayment model for nonspecialized commodity web-services based on microcomputations. In our model, a user that wishes to access online content (offered by a website) does not need to register or pay to access the website; instead, he will accept to run microcomputations on behalf of the service provider in exchange for access to the content. These microcomputations can, for example, support ongoing computing projects that have clear social benefits (e.g., projects relating to medical research) or can contribute towards commercial computing projects. We analyze the security and privacy of our proposal and we show that it preserves the privacy of users. We argue that this micropayment model is economically and technically viable and that it can be integrated in existing distributed computing frameworks (e.g., the BOINC platform). In this respect, we implement a prototype of a system based on our model and we deploy our prototype on Amazon Mechanical Turk to evaluate its performance and usability given a large number of users. Our results show that our proposed scheme does not affect the browsing experience of users and is likely to be used by a non-trivial proportion of users. Finally, we empirically show that our scheme incurs comparable bandwidth and CPU consumption to the resource usage incurred by online advertisements featured in popular websites

A structural approach to handling endogeneity in strategic management: the case of RBV

A. NANDIALATH, J. DOTSON, R. DURAND

European Management Review

avril 2014, vol. 11, n°1, pp.47-62

Départements : Stratégie et Politique d’Entreprise, GREGHEC (CNRS)

Mots clés : Resource based view, Bayesian modeling, Endogeneity, Structural modeling, Competitive strategy


In this paper we posit that the lack of consensus about empirical tests of resource based view (RBV) could be the result of endogenous resource picking on the part of firms. If resources are endogenously selected, regression based methods that examine their connection to firm performance will be mis-estimated. We show that traditional remedies for endogeneity do not resolve this problem when returns to resources are heterogeneous (as theorized under RBV) and when managers act with at least partial knowledge of the expected, idiosyncratic return (as theorized under the strategic factor market hypotheses). As such, we develop a Bayesian approach that solves this endogeneity problem by directly incorporating resource picking into the modeling framework. We illustrate the validity of our approach through the use of a comprehensive simulation study and show that our proposed approach outperforms traditional linear models (including traditional cures of endogeneity and unobserved heterogeneity) under a variety of conditions. Our findings suggest that: (1) research in strategy requires a more careful and deeper understanding of potential sources of endogeneity and (2) the use of Bayesian methods in management can help develop more theoretically motivated empirical approaches to hypothesis testing

Ai confini dell’arcipelago familiare: unioni tra persone dello stesso sesso e danno da perdita di familiare

M. M. WINKLER

Responsabilità civile e previdenza

2014, vol. 79, n°2, pp.645-655

Départements : Droit et fiscalité, GREGHEC (CNRS)

http://www.associazionegea.it/wp/wp-content/uploads/2013/12/12-06-2014_Winkler.pdf


The above captioned ruling of the Court of Appeals of Milan concerns the right of the surviving partner to claim the damages arising out of the death of his same-sex cohabiting partner. The Court, partially reversing the Tribunal's ruling, granted his claim, which the Court derived from the occurred violation of the right, to which homosexual people are entitled, to freely live their condition as a couple, right that was recognized by the judgment of the Italian Constitutional Court No. 138 of 2010

An Empirical Investigation of the Impact of Audit and Auditor Characteristics on Audit Performance

W. ALISSA, V. CAPKUN, T. JEANJEAN, N. SUCA

Accounting Organizations and Society

octobre 2014, vol. 39, n°7, pp.495-510

Départements : Comptabilité et Contrôle de Gestion, GREGHEC (CNRS)

Mots clés : Auditor effort, Auditor experience, Task complexity, Auditor performance, Tax audits

http://ssrn.com/abstract=2458850


We use a unique and confidential database of 15,392 tax audits performed by the Croatian Tax Administration during the 2002-2006 period to examine the impact of task complexity, auditor experience, and auditor effort on audit performance. We provide external validation to prior experimental and analytical research showing that task complexity decreases while auditor experience and effort increase audit performance. We also extend this literature by examining the roles of task complexity and experience in moderating the impact of the effort on audit performance. We find that task complexity mitigates, while experience enhances the positive relationship between auditor effort and performance. However, we also find that auditor experience reinforces the positive effect of auditor effort on performance to a greater degree when complexity is high. Taken together, our findings provide new evidence on how audit and auditor characteristics impact audit performance, and new insight into how task complexity and auditor experience separately and jointly moderate the impact of auditor effort on performance

Analogies and Theories: The Role of Simplicity and the Emergence of Norms

G. GAYER, I. GILBOA

Games and Economic Behavior

janvier 2014, vol. 83, pp.267–283

Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

Mots clés : Case-based reasoning, Rule-based reasoning, Model selection, Social norms, Equilibrium selection

http://dx.doi.org/10.1016/j.geb.2013.11.003


We consider the dynamics of reasoning by general rules (theories) and by specific cases (analogies). When an agent faces an exogenous process, we show that, under mild conditions, if reality happens to be simple, the agent will converge to adopt a theory and discard analogical thinking. If, however, reality is complex, analogical reasoning is unlikely to disappear. By contrast, when the agent is a player in a large population coordination game, and the process is generated by all players' predictions, convergence to a theory is much more likely. This may explain how a large population of players selects an equilibrium in such a game, and how social norms emerge. Mixed cases, involving noisy endogenous processes are likely to give rise to complex dynamics of reasoning, switching between theories and analogies

Asynchronicity and coordination in common and opposing interest games

R. CALCAGNO, Y. KAMADA, S. LOVO, T. SUGAYA

Theoretical Economics

mai 2014, vol. 9, n°2, pp.409-434

Départements : Finance, GREGHEC (CNRS)

Mots clés : Revision games, Pre-opening, finite horizon, Equilibrium selection, Asynchronous moves


We study games endowed with a pre-play phase in which players repare the actions that will be implemented at a predetermined deadline. In the preparation phase, each player stochastically receives opportunities to revise her actions, and the ?nally-revised action is taken at the deadline. In 2-player “common interest” games, where there exists a best action pro?le for all players, this best action pro?le is the only equilibrium outcome of the dynamic game. In “opposing interest” games, which are 2 × 2 games with Pareto-unranked strict Nash equilibria, the equilibrium outcome of the dynamic game is generically unique and corresponds to one of the stage-game strict Nash equilibria. Which equilibrium prevails depends on the payo? structure and on the relative frequency of the arrivals of revision opportunities for each of the players.

Beware of black swans: Taking stock of the description-experience gap in decision under uncertainty

A. DE PALMA, M. ABDELLAOUI, G. ATTANASI, M. BEN-AKIVA, I. EREV, H. FEHR-DUDA, D. FOK, C. FOX, R. HERTWIG, N. PICARD, P. P. WAKKER, J. WALKER, M. WEBER

Marketing Letters

septembre 2014, vol. 25, n°3, pp.269-280

Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

Mots clés : Ambiguity, Black swans, Description-based decision making, Fourfold pattern, Probabilistic choices, Risk


Uncertainty pervades most aspects of life. From selecting a new technology to choosing a career, decision makers rarely know in advance the exact outcomes of their decisions. Whereas the consequences of decisions in standard decision theory are explicitly described (the decision from description (DFD) paradigm), the consequences of decisions in the recent decision from experience (DFE) paradigm are learned from experience. In DFD, decision makers typically overrespond to rare events. That is, rare events have more impact on decisions than their objective probabilities warrant (overweighting). In DFE, decision makers typically exhibit the opposite pattern, underresponding to rare events. That is, rare events may have less impact on decisions than their objective probabilities warrant (underweighting). In extreme cases, rare events are completely neglected, a pattern known as the 'Black Swan effect.' This contrast between DFD and DFE is known as a description-experience gap. In this paper, we discuss several tentative interpretations arising from our interdisciplinary examination of this gap. First, while a source of underweighting of rare events in DFE may be sampling error, we observe that a robust description-experience gap remains when these factors are not at play. Second, the residual description-experience gap is not only about experience per se but also about the way in which information concerning the probability distribution over the outcomes is learned in DFE. Econometric error theories may reveal that different assumed error structures in DFD and DFE also contribute to the gap

Business sustainability: It is about time

M. DESJARDINE, P. BANSAL

Strategic Organization

février 2014, vol. 12, n°1, pp.70-78

Départements : Stratégie et Politique d’Entreprise, GREGHEC (CNRS)

Mots clés : Business sustainability, short-termism, corporate social responsibility, systems thinking

http://soq.sagepub.com/content/12/1/70.short?rss=1&ssource=mfr


Sustainability is fast becoming fashionable in strategic management, and yet its meaning is often elusive. Some people restrict sustainability to environmental issues, and others use it synonymously with corporate social responsibility. In this essay, we return to the roots of its original meaning and argue that sustainability requires the consideration of time. Sustainability obliges firms to make intertemporal trade-offs to safeguard intergenerational equity. In this essay, we clarify the meaning of sustainability by showing that the notion of ‘time’ discriminates sustainability from responsibility and other similar concepts. We then argue that the omission of time from most strategic management has contributed to short-termism, which is the bane sustainability. We conclude with directions for future research that will integrate sustainability into strategy and contribute to a world in which both business and society can thrive for generations to come

Choosing a Digital Content Strategy: How Much Should be Free?

D. HALBHEER, F. STAHL, O. KOENIGSBERG, D. LEHMANN

International Journal of Research in Marketing

juin 2014, vol. 31, n°2, pp.192-206

Départements : Marketing, GREGHEC (CNRS)

Mots clés : Information Goods, Sampling, Content Pricing, Advertising, Dorfman-Steiner Condition


This paper studies content strategies for online publishers of digital informationgoods. It examines sampling strategies and compares their performance to paidcontent and free content strategies. A sampling strategy, where some of the contentis offered for free and consumers are charged for access to the rest, is knownas a “metered model” in the newspaper industry. We analyze optimal decisionsconcerning the size of the sample and the price of the paid content when samplingserves the dual purpose of disclosing content quality and generating advertisingrevenue. We show in a reduced-form model how the publisher’s optimal ratio ofadvertising revenue to sales revenue is linked to characteristics of both the contentmarket and the advertising market. We assume that consumers learn about contentquality from the free samples in a Bayesian fashion. Surprisingly, we find that itcan be optimal for the publisher to generate advertising revenue by offering freesamples even when sampling reduces both prior quality expectations and contentdemand. In addition, we show that it can be optimal for the publisher to refrainfrom revealing quality through free samples when advertising effectiveness is lowand content quality is high

Classification models via Tabu search: An application to early stage venture classification

S. ELHEDHLI, C. AKDEMIR, T. ASTEBRO

Expert Systems with Applications

15 décembre 2014, vol. 41, n°18, pp.8085-8091

Départements : Economie et Sciences de la décision, GREGHEC (CNRS)

Mots clés : Experts classify early stage venture proposals based on integer-valued attributes.•Model a disjunctive if-then rule as a large-scale mixed integer program.•Explore Benders decomposition and Tabu search.•Tabu search provides excellent classification accuracy.


We model the decision making process used by Experts at the Canadian Innovation Centre to classify early stage venture proposals based on potential commercial success. The decision is based on thirty-seven attributes that take values in {-1,0,1}. We adopt a conjunctive decision framework due to Åstebro and Elhedhli (2005) that selects a subset of attributes and determines two threshold values: one for the maximum allowed negatives (n) and one for minimum required positives (p). A proposal is classified as a success if the number of positives is greater than or equal to p and the number of negatives is less than or equal to n over the selected attributes. Based on a data set of 561 observations, the selection of attributes and the determination of the threshold values is modeled as a large-scale mixed integer program. Two solution approaches are explored: Benders decomposition and Tabu search. The first, was very slow to converge, while the second provided high quality solutions quickly. Tabu search provides excellent classification accuracy for predicting commercial successes as well as replicating Experts’ forecasts, opening the venue for the use of Tabu search in scoring and classification problems


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