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

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

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

Business Partnering: Is It All That Good?

J. BURNS, L. WARREN, J. OLIVEIRA

Controlling & Management Review

avril 2014, vol. 58, n°2, pp.36-41

Départements : Comptabilité et Contrôle de Gestion


Challengers from within economic institutions: A second-class social movement? A response to Déjean, Giamporcaro, Gond, Leca and Penalva-Icher's comment on French SRI

Diane-Laure ARJALIES

Journal of Business Ethics

août 2014, vol. 123, n°2, pp.257-262

Départements : Comptabilité et Contrôle de Gestion

Mots clés : Institutional change, Mainstreaming, Social movement, Socially responsible investment

http://ssrn.com/abstract=2291395


In a recent comment made about my paper 'A Social Movement Perspective on Finance: How Socially Responsible Investment Mattered' (J Bus Ethics 92:57-78, 2010), published in this journal, Déjean, Giamporcaro, Gond, Leca and Penalva-Icher (J Bus Ethics 112:205-212, 2013) strongly criticize the social movement perspective adopted on French SRI. They both contest the empirical analysis of the movement and the possibility for insiders to trigger institutional change towards sustainability. This answer aims to address the different concerns raised throughout their comment and illuminate the differences between both approaches. It first explains why SRI in France can be considered as a social movement, despite not being protest-oriented. It then reflects on the dangers of systematically associating societal change with radical activism. It concludes by elaborating on the importance of acknowledging the potential contribution of reformist movements from within the economic institutions to the enhancement of the social good

Costing Practices in Healthcare

C. CHAPMAN, A. KERN, A. LAGUECIR

Accounting Horizons

juin 2014, vol. 28, n°2, pp.353-364

Départements : Comptabilité et Contrôle de Gestion


Fishing for excuses and performance evaluation

F. LARMANDE, J. PONSSARD

Review of Accounting Studies

juin 2014, vol. 19, n°2, pp.988-1008

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

Mots clés : Performance measurement Manipulation Controllability principle Excuse culture Influence activity


We study a principal–agent model in which the agent can provide ex post additional relevant information regarding his performance. In particular, he can provide a legitimate excuse, that is, evidence that a poor result is only due to factors outside his control. However, building a convincing case requires time, time that is not spent on exerting productive effort and thus generating information represents an opportunity cost. We obtain necessary and sufficient conditions for the principal to prefer a policy of adjusting ex post the performance measure for the information provided by the agent to a policy of conforming to a result-based system with no adjustments. The risk aversion and a possible limited liability of the agent play an important role in the analysis. This paper clarifies the issues associated with the so-called “excuse culture” prevailing in some organizations

Fishing for excuses and performance evaluation

F. LARMANDE, J.-P. PONSSARD

Review of Accounting Studies

juin 2014, vol. 19, pp.988-1008

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

Mots clés : Performance measurement, Manipulation, Controllability principle, Excuse culture, Influence activity


We study a principal–agent model in which the agent can provide expost additional relevant information regarding his performance. In particular, he canprovide a legitimate excuse, that is, evidence that a poor result is only due to factorsoutside his control. However, building a convincing case requires time, time that isnot spent on exerting productive effort and thus generating information representsan opportunity cost. We obtain necessary and sufficient conditions for the principalto prefer a policy of adjusting ex post the performance measure for the informationprovided by the agent to a policy of conforming to a result-based system with noadjustments. The risk aversion and a possible limited liability of the agent play animportant role in the analysis. This paper clarifies the issues associated with the socalled‘‘excuse culture’’ prevailing in some organizations

Is Bitcoin a Decentralized Currency ?

A. GERVAIS, V. CAPKUN, G. O. KARAME, S. CAPKUN

IEEE Security & Privacy

mai-juin 2014, vol. 12, n°3, pp.54-60

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

Mots clés : Cryptography, Proposals, Peer-to-peer computing, Internet, Online banking, Privacy, Bitcoin, Decentralized decision process, Security


Bitcoin has achieved large-scale acceptance and popularity by promising its users a fully decentralized and low-cost virtual currency system. However, recent incidents and observations are revealing the true limits of decentralization in the Bitcoin system. In this article, we show that the vital operations and decisions that Bitcoin is currently undertaking are not decentralized. More specifically, we show that a limited set of entities currently control the services, decision making, mining, and the incident resolution processes in Bitcoin. We also show that third-party entities can unilaterally decide to “devalue” any specific set of Bitcoin addresses pertaining to any entity participating in the system. Finally, we explore possible avenues to enhance the decentralization in the Bitcoin system

Microcomputations as Micropayments in Web-based Services

G. 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)

Mots clés : Distributed computing microcomputations micropayments Monetization privacy


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


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