Does Resorting to Online Dispute Resolution Promote Agreements? Experimental Evidence

This paper presents the results of an experiment performed to test the properties of an innovative bargaining mechanism (called automated negotiation) used to resolve disputes arising from Internet-based transactions. Automated negotiation is an online sealed-bid process in which an automated algorithm evaluates bids from the parties and settles the case if the offers are within a prescribed range. The observed individual behavior, based on 40 rounds of bargaining, is shown to be drastically affected by the design of automated negotiation. The settlement rule encourages disputants to behave strategically by adopting aggressive bargaining positions, which implies that the mechanism is not able to promote agreements and generate efficiency. This conclusion is consistent with the experimental results on arbitration and the well-known chilling effect: Automated negotiation tends to "chill" bargaining as it creates incentives for individuals to misrepresent their true valuations and discourage them to converge on their own. However, this perverse effect induced by the settlement rule depends strongly on the conflict situation. When the threat that a disagreement occurs is more credible, the strategic effect is reduced since defendants are more interested in maximizing the efficiency of a settlement than their own expected profit.Online Dispute Resolution, Arbitration, Experimental Economics, Electronic Commerce, Bargaining

Training Without Certification: An Experimental Study

Our study considers the question of training in firms using an experimental laboratory approach. We investigate the following questions : What conditions, excluding external certification, will bring workers and employers to cooperate and share a rent generated by the workers' training? What conditions will induce workers to accept the training offer, for employers to initially offer the training and to reward the trained workers in the last stage of the game? We analyse the impact of the size of the rent created by training and the existence of an information system on employer reputation rewarding trained employees. Reputation does matter to induce cooperation, but in the absence of external institutions, coordination on the optimal outcome remains difficult. Nous étudions les déterminants de la formation des travailleurs en entreprises en mobilisant l’économie expérimentale. Nous voulons répondre aux questions suivantes : Sous quelles conditions, excluant la formule d’une accréditation externe, les travailleurs et les employeurs acceptent de collaborer dans la formation des travailleurs? Sous quelles conditions une offre de formation est proposée par l’employeur, acceptée par le travailleur, et honorée par l’employeur dans la dernière phase du jeu? L’étude montre l’impact du niveau des gains générés par la formation sur la coopération entre employeurs et travailleurs. Elle montre également qu’un système d’information qui révèle aux travailleurs la réputation de l’employeur à honorer ses promesses, favorise la coopération et la formation des travailleurs. Mais, néanmoins, sans institution externe validant la formation reçue, la coopération optimale demeure difficile à réaliser.general and specific training in firms, accreditation, cooperation and reputation, experimental economics., formation générale et spécifique en entreprises, accréditation, coopération et réputation, économie expérimentale.

Using the Sun to estimate Earth-like planets detection capabilities. V. Parameterizing the impact of solar activity components on radial velocities

Stellar activity induced by active structures (eg, spots, faculae) is known to strongly impact the radial velocity time series. It then limits the detection of small planetary RV signals (eg, an Earth-mass planet in the habitable zone of a solar-like star). In previous papers, we studied the detectability of such planets around the Sun seen as an edge-on star. For that purpose, we computed the RV and photometric variations induced by solar magnetic activity, using all active structures observed over one entire cycle. Our goal is to perform similar studies on stars with different physical and geometrical properties. As a first step, we focus on Sun-like stars seen with various inclinations, and on estimating detection capabilities with forthcoming instruments. To do so, we first parameterize the solar active structures with the most realistic pattern so as to obtain results consistent with the observed ones. We simulate the growth, evolution and decay of solar spots, faculae and network, using parameters and empiric laws derived from solar observations and literature. We generate the corresponding structure lists over a full solar cycle. We then build the resulting spectra and deduce the RV and photometric variations for a `Sun' seen with various inclinations. The produced RV signal takes into account the photometric contribution of structures as well as the attenuation of the convective blueshift. The comparison between our simulated activity pattern and the observed one validates our model. We show that the inclination of the stellar rotation axis has a significant impact on the time series. RV long-term amplitudes as well as short-term jitters are significantly reduced when going from edge-on to pole-on configurations. Assuming spin-orbit alignment, the optimal configuration for planet detection is an inclined star (i~45{\deg}).Comment: Accepted to Astronomy and Astrophysics on May, 27th 2015. The manuscript includes 22 pages, 20 figure

Variability in stellar granulation and convective blueshift with spectral type and magnetic activity. II. From young to old main-sequence K-G-F stars

The inhibition of small-scale convection in the Sun dominates the long-term radial velocity (RV) variability: it therefore has a critical effect on light exoplanet detectability using RV techniques. We here extend our previous analysis of stellar convective blueshift and its dependence on magnetic activity to a larger sample of stars in order to extend the Teff range, to study the impact of other stellar properties, and finally to improve the comparison between observed RV jitter and expected RV variations. We estimate a differential velocity shift for Fe and Ti lines of different depths and derive an absolute convective blueshift using the Sun as a reference for a sample of 360 F7-K4 stars with different properties (age, Teff, metallicity). We confirm the strong variation in convective blueshift with Teff and its dependence on (as shown in the line list in Paper I) activity level. Although we do not observe a significant effect of age or cyclic activity, stars with a higher metallicity tend to have a lower convective blueshift, with a larger effect than expected from numerical simulations. Finally, we estimate that for 71% of the stars in our sample the RV and LogR'HK variations are compatible with the effect of activity on convection, as observed in the solar case, while for the other stars, other sources (such as binarity or companions) must be invoked to explain the large RV variations. We also confirm a relationship between LogR'HK and metallicity, which may affect discussions of the possible relationship between metallicity and exoplanets, as RV surveys are biased toward low LogR'HK and possibly toward high-metallicity stars. We conclude that activity and metallicity strongly affect the small-scale convection levels in stars in the F7-K4 range, with a lower amplitude for the lower mass stars and a larger amplitude for low-metallicity stars.Comment: 12 pages, 9 figures ; accepted in Astronomy and Astrophysic

Does Resorting to Online Dispute Resolution Promote Agreements? Experimental Evidence

This paper presents an experiment performed to test the properties of an innovativebargaining mechanism (called automated negotiation) used to resolve disputes arising fromInternet-based transactions. The main result shows that the settlement rule tends to chillbargaining as it creates incentives for individuals to misrepresent their true valuations, whichimplies that automated negotiation is not able to promote agreements. However, this perverseeffect depends strongly on the conflict situation. When the threat that a disagreement occurs ismore credible, the strategic effect is reduced since defendants are more interested inmaximizing the efficiency of a settlement than their own expected profit. The implications ofthese results are then used to discuss the potential role of public regulation and reputationmechanisms in Cyberspace: Online Dispute Resolution, Electronic Commerce, Bargaining, Arbitration,Experimental Economics

Early or Late Conflict Settlement in a Variety of Games - An Experimental Study -

The game theoretic prediction for alternating offer bargaining depends crucially on how "the pie'' changes over time, and whether the proposer in an early round has ultimatum power. We experimentally study eight such games. Each game is once repeated before being followed by the next one, which defines a cycle of altogether 16 successive plays. Participants play three such cycles. There are no major experience effects but strong and reliable effects of anticipated rule changes. The latter, however, are not due to strategic considerations but rather to the social norms of fairness and efficiency. La théorie des jeux prédit que la résolution des jeux de négociation séquentielle dépend essentiellement de l'évolution de la rente à partager dans le temps (taux d'escompte), et du pouvoir d'ultimatum de l'offreur à la première période. Nous étudions à l'aide de la méthode expérimentale huit jeux de négociation séquentielle afin d'évaluer l'impact du pouvoir de négociation et du taux d'escompte sur les comportements. Chaque jeu est répété une fois avant de passer à un nouveau jeu, notre test est composé de cycle composé de 16 jeux consécutifs. Les participants ont été confrontés à 3 cycles. Au cours du test, aucun effet d'expérience lié à la répétition des jeux n'a été détecté. Les participants ont adopté un comportement stable et robuste d'anticipation des changements de règle de jeu. Les stratégies mises en ?uvre font référence à des considérations, non stratégiques, basées à la fois sur des normes sociales d'équité et d'efficience.Alternating bargaining games, ultimatum, Jeux de négociation séquentiels, ultimatum

Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample

Massive, Main-Sequence AF-type stars have so far remained unexplored in past radial velocity surveys, due to their small number of spectral lines and their high rotational velocities that prevent the classic RV computation method. Our aim was to search for giant planets around AF MS stars, to get first statistical information on their occurrence rate and to compare the results with evolved stars and lower-mass MS stars. We used the HARPS spectrograph located on the 3.6m telescope at ESO La Silla Observatory to observe 108 AF MS stars with B-V in the -0.04 to 0.58 range and masses in the range 1.1-3.6 Msun. We used our SAFIR software specifically developed to compute the radial velocities of these early-type stars. We report the new detection of a mpsini = 4.51 Mjup companion with a ~826-day period to the F6V dwarf HD111998. We present new data on the 2-planet system around the F6IV-V dwarf HD60532. We also report the detection of 14 binaries with long-term RV trends. 70% of our targets show detection limits between 0.1 and 10 Mjup in the 1 to 10^3-day range. We derive brown dwarf (13 < mpsini < 80 Mjup) occurrence rates in the 1 to 10^3-day range of $2_{-2}^{+5}$% and $2.6_{-2.6}^{+6.7}$% for stars with masses in the ranges 1.1-1.5 and 1.5-3 Msun, respectively. As for Jupiter-mass companions (1 < mpsini < 13 Mjup), we get occurrence rates in the 1 to 10^3-day range of $4_{-0.9}^{+5.9}$% and $6.3_{-6.3}^{+15.9}$% respectively for the same stellar mass ranges. When considering the same Jupiter-mass companions but periods in the 1 to 100-day range only, we get occurrence rates of $2_{-2}^{+5.2}$% and $3.9_{-3.9}^{+9.9}$%. Given the present error bars, these results do not show a significant difference with companion frequencies derived for solar-like stars.Comment: 23 pages (text), 15 figures, accepted in Astronomy and Astrophysic

A.G. Stakhanov in Gaumont Pathé’s Soviet Film Archives: Between Physical Performance and Instrumentalisation

The depiction of the miner A.G. Stakhanov in newsreels from the Gaumont Pathé archives highlights the representations of this physical performance used in the specific economic and political environment of the USSR during the interwar period. The Soviet worker is idealized as a national hero. At that time, the Soviet government was looking for the “New Man” and “new technical standards” (Stalin, 1977) and Stakhanov lost his individuality, becoming “only an official agent of the state” (Vigne, 1984). This article examines the evolution of the memory of Stakhanov’s record mining achievement, moving from a retrospective point of view to a celebration and finally to commemoration (Ory, 1992)