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 primal condition for approachability with partial monitoring

S. MANNOR, V. PERCHET, G. STOLTZ

Journal of Dynamics and Games

juillet 2014, vol. 1, n°3, pp.447-469

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

Mots clés : Approachability theory, Online learning, Imperfect monitoring, Partial monitoring, Signals


In approachability with full monitoring there are two types of conditions that are known to be equivalent for convex sets: a primal and a dual condition. The primal one is of the form: a set C is approachable if and only all containing half-spaces are approachable in the one-shot game. The dual condition is of the form: a convex set C is approachable if and only if it intersects all payoff sets of a certain form. We consider approachability in games with partial monitoring. In previous works [5,7] we provided a dual characterization of approachable convex sets and we also exhibited efficient strategies in the case where C is a polytope. In this paper we provide primal conditions on a convex set to be approachable with partial monitoring. They depend on a modified reward function and lead to approachability strategies based on modified payoff functions and that proceed by projections similarly to Blackwell's (1956) strategy. This is in contrast with previously studied strategies in this context that relied mostly on the signaling structure and aimed at estimating well the distributions of the signals received. Our results generalize classical results by Kohlberg [3] (see also [6]) and apply to games with arbitrary signaling structure as well as to arbitrary convex sets

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

Acts, Persons, and Intuitions: Person-Centered Cues and Gut Reactions to Harmless Transgressions

E. L. UHLMANN, L. ZHU

Social Psychological and Personality Science

avril 2014, vol. 5, n°3, pp.279-285

Départements : Management et Ressources Humaines

Mots clés : Person-centered moral judgments, Moral intuitions, Social intuitionist model, Moral dumbfounding, Informational value, Act-person dissociations


Negative gut reactions to harmless-but-offensive transgressions can be driven by inferences about the moral character of the agent more so than condemnation of the act itself. Dissociations between moral judgments of acts and persons emerged, such that participants viewed a harmless-but-offensive transgression to be a less immoral act than a harmful act, yet more indicative of poor moral character. Participants were more likely to become "morally dumbfounded'' when asked to justify their judgments of a harmless-but-offensive act relative to a harmful act. However, they were significantly less likely to become morally dumbfounded when asked to justify character judgments of persons who engaged in the harmless-but-offensive transgression, an effect based in part on the information-rich nature of such behaviors. Distinguishing between evaluations of acts and persons helps account for both moral outrage over harmless transgressions and when individuals are (and are not) at a loss to explain their own judgments

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

Are Novice Private Equity Funds Risk-Takers? Evidence From a Comparison with Established Funds

P. GIOT, U. HEGE, A. SCHWIENBACHER

Journal of Corporate Finance

août 2014, vol. 27, pp.55-71

Départements : Finance, GREGHEC (CNRS)

Mots clés : private equity funds; venture capital; buyouts; learning; reputation; risk-taking


This paper explores whether private equity firms that are new to the industry take excessive risks relative to funds from established firms. We use differences between the implicit incentives of managers of experienced and of novice funds as an identification strategy. We find that novice funds invest more slowly than experienced funds, contradicting the risk-taking hypothesis. However, the size of their investments, in value and as fraction of fund size, is larger; this could be consistent with risk-shifting by novice funds but also with alternative hypotheses. We find that the size difference increases over time and is absent from buyout investments. We also find that novice funds tend to underperform most dramatically for early large investments, and that the size of their investments increases after a first successful exit. These and other findings are in conflict with the excessive risk-taking hypothesis, but largely consistent with alternative explanations that emphasize differences in expertise

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, ?nite 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.

Attributional Tendencies in Cultural Explanations of M&A Performance

E. VAARA, P. JUNNI, R. SARALA, M. EHRNROOTH, A. KOVESHNIKOV

Strategic Management Journal

septembre 2014, vol. 35, n°9, pp.1302-1317


Audit Fees In Family Firms: Evidence From U.S. Listed Companies

C. LESAGE, C. BEN ALI

Journal of Applied Business Research

2014, vol. 30, n°3, pp.807-815

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

Mots clés : Family Firms; Audit Fees; Agency Conflicts; Corporate Governance


Family businesses are an important part of the world economy (Anderson & Reeb, 2003) and differ considerably from non-family firms with regard to corporate governance. However, despite their difference, family businesses have received relatively little research attention. Our study contributes to this growing research by empirically investigating the relationship between family shareholding and audit pricing. Using a sample of 3,291 firm-year observations of major U.S. listed companies, for the 2006–2008 period, our results demonstrate that audit fees are negatively associated with family shareholding after taking into account time-varying effects and industry effects as well as traditional control variables. The empirical results are robust to alternativefamily shareholding measures and estimation model specifications. Our results are consistent with the convergence-of-interests hypothesis suggesting that family firms face lower manager/shareholders agency costs. Auditors charge lower fees for family firms because of lower information asymmetry and risk given that the controlling family is well informed about the firmand is better able to monitor managerial decisions


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