ProtoDUNEs

These proceedings review the two DUNE prototype detectors, namely Single- and Dual-Phase ProtoDUNEs. The detectors, both employing liquid argon Time Projection Chambers (LAr TPCs), are currently being built at CERN as part of the ProtoDUNE experimental programme. Such R&D programme aims at validating the prototypes design and technology, which will eventually be applied to the DUNE Far Detector at the Sanford Underground Research Facility (SURF).Comment: Talk presented at NuPhys2016 (London, 12-14 December 2016). 8 pages, LaTeX, 3 figure

Congestion, Private Peering and Capacity Investment on the Internet.

This paper presents a model of private bilateral and multilateral peering arrangements between Internet backbone providers when the network is congested. We study how different forms of interconnection and the competitive conditions of the market affect backbones' investments in network and peering point capacities. We show that network and peering point capacities are equilibrium complements; increasing competition reduces capacity investments (under-investment), thus worsening the quality of service both with multilateral and bilateral peering; under bilateral peering the inefficiency is less severe. Because of under-investment, welfare may be lower when the market is more competitive. We also show that asymmetries between backbones, which can take the form of uneven content distribution or product differentiation, may reduce under-investment and improve the quality of service. The introduction of an "inverse capacity interconnection fee" where providers pay each other a fee which is negatively correlated with their installed capacity may play the role of a coordinating mechanism towards a Pareto superior outcome.Internet, peering, congestion, QoS, capacity investment, interconnection

Thermal CFTs in momentum space

We study some aspects of conformal field theories at finite temperature in momentum space. We provide a formula for the Fourier transform of a thermal conformal block and study its analytic properties. In particular we show that the Fourier transform vanishes when the conformal dimension and spin are those of a "double twist" operator $\Delta = 2\Delta_\phi + \ell + 2n$. By analytically continuing to Lorentzian signature we show that the spectral density at high spatial momenta has support on the spectrum condition $|\omega| > |k|$. This leads to a series of sum rules. Finally, we explicitly match the thermal block expansion with the momentum space Green's function at finite temperature in several examples.Comment: Added 1 note and 1 referenc

One-Way Compatibility, Two-Way Compatibility and Entry in Network Industries

We study the strategic choice of compatibility between two initially incompatible network goods in a two-stage game played by an incumbent and an entrant firm. Compatibility may be achieved by means of a converter. We derive a number of results under different assumptions about the nature of the converter (one-way \emph{vs} two-way) and the existence of property rights. In the case of a two-way converter, which can only be supplied by the incumbent, incompatibility will result in equilibrium. When both firms can build a one-way converter and there are no property rights on the necessary technical specifications, the unique equilibrium involves full compatibility. Finally, when each firm has property rights on its technical specifications, full incompatibility and preemption are again observed at the equilibrium. With incompatibility, entry deterrence occurs for sufficiently strong network effects. The welfare analysis shows that the equilibrium compatibility regime is socially inefficient for most levels of the network effects.Network externalities, one-way compatibility, two-way compatibility, entry

One-Way Compatibility, Two-Way Compatibility and Entry in Network Industries

We study the strategic choice of compatibility between two initially incompatible software packages in a two-stage game by an incumbent and an entrant firm. Consumers enjoy network externality in consumption and maximise expected surplus over the two periods. Compatibility may be achieved by means of a converter. We derive a number of results under diÆerent assumptions about the nature of the converter (one-way vs two-way) and the existence of property rights. In the case of a two-way converter, which can only be supplied by the incumbent, incompatibility will result in equilibrium and depending on the strength of network externalities the incumbent may deter entry. When both firms can build a one-way converter and there are no property rights on the necessary technical specifications, the only fulfilled expectations subgame perfect equilibrium involves full compatibility. Finally, when each firm has property rights on its technical specifications, full incompatibility and preemption are again observed at the equilibrium. Entry deterrence will then occur for su±ciently strong network eÆects. The analysis generalises to any market where network externalities are present.

On the role of public policies supporting Free/Open Source Software: an European perspective

Available in the .pd

Open Source vs Closed Source Software: Public Policies in the Software Market

This paper analyses the impact of public policies supporting open source software (OSS). Users can be divided between those who know about the existence of OSS, the "informed" adopters, and the "uninformed" ones; the presence of uniformed users yields to market failures that justify government intervention. We study three policies: i) mandatory adoption, when government forces public agencies, schools and universities to adopt OSS, ii) information campaign, when the government informs the uninformed users about the existence and the characteristics of OSS and, iii) subsidisation, when consumers are payed a subsidy when adopting OSS. We show that the second policy enhances welfare, the third is always welfare decreasing while mandatory adoption can be either good or bad for society depending on the number of informed and uninformed adopters. We extend the model to the presence of network effects and we show that strong externalities require "drastic" policies.software market, open source software, mandatory adoption, information campaign, subsidisation, network externalities

Sequential innovations with unobservable follow-on investments

We consider a cumulative innovation process in which a follow-on innovator invests in R&D activities that influence both the expected commercial value as well as the novelty of its innovation. When the second innovator investments are not servable,licensing of the first innovation never occurs efficiently, and, at the equilibrium, the follow-on innovator either underinvests or overinvests. We show that a large patent breadth may be harmful for the first innovator too, and therefore Pareto-dominated;as long as the undervinvestment problem becomes more pronounced, the value generated by the follow-on innovator reduces, and so do the licensing revenues of the first inventor.sequential innovation, patents, licensing, intellectual property

From Planning to Mature: on the Determinants of Open Source Take-Off

Thanks to a recent and vast empirical literature, we know in details how the most popular open source projects are organized and why they succeed. However open source is not only Linux: in this paper we use a large data-set obtained from SourceForge.net to estimate the main determinants of the progress in the development of a stable and mature code of an open source software. We show that projects geared towards sophisticated users (i.e. system administrators) or projects aimed at developing tools for the Internet, multimedia and software have greater chances to reach an advanced development stage. On the contrary, projects devoted to the production of applications for games and telecommunication as well as projects distributed under highly restrictive licensing terms (GPL) have a significantly smaller probability to advance. Interestingly, we find that the size of the "community of developers" increases the chances of progress but this effect decreases as the community gets larger, a signal of possible coordination problems. Finally, we show that the determinants of projects' development stage change with the age of the project in many dimensions thus supporting the common perception of open source as an extremely dynamic phenomenon.software market, open source software, development status, intended audience, license