How Delegation Improves Commitment

We often use delegation as a commitment device if a government faces problems of timeinconsistency. McCallum (1995, AER P&P) challenged this practice, claiming that delegation merely relocates the commitment problem but does not solve it. In a model where delegation and specific policies are subject to the same commitment technology it is shown that McCallum’s conjecture holds if optimal ex-ante policies are fixed. However, with a flexibility-credibility trade-off delegation is both desirable and improves credibility. While delegation does not increase commitment per se it makes it more attractive and increases investments in credibility. Delegation can therefore serve as a valid commitment device.Time-inconsistency, commitment, delegation

The Design of Permit Schemes and Environmental Innovation

Most real world emission permit schemes are in effect hybrid instruments that feature both quantity and price controls. While the effects of price bounds are well understood for issues such as uncertain abatement costs it has not been investigated how such bounds affect time-consistency of environmental regulation and research incentives. The present paper analyzes these issues for two types of innovation. While price bounds increase static efficiency they reduce incentives to innovate. Commitment on details of a scheme’s design might be necessary to avoid the latter.Environmental Regulation, Hybrid Instruments, Innovation, Time-inconsistency

The Merits of New Pollutants and How to Get Them When Patents Are Granted

The performance of market based environmental regulation is affected by patents and vice versa. This interaction is studied for a new type of innovation where new technologies reduce emissions of a specific pollutant but at the same time cause a new type of damage. A robust finding is that the efficiency of permits is affected by monopoly pricing of the patent-holding firm. This result carries over to other types of innovation. Taxes are inefficient if technologies produce perfect substitutes and share all scarce inputs. Moreover, the optimal tax on pollution might be negative.Innovation; Environment; Instrument Choice; Patents; Monopoly Pricing

On Resource Aware Algorithms in Epidemic Live Streaming

Epidemic-style diffusion schemes have been previously proposed for achieving peer-to-peer live streaming. Their performance trade-offs have been deeply analyzed for homogeneous systems, where all peers have the same upload capacity. However, epidemic schemes designed for heterogeneous systems have not been completely understood yet. In this report we focus on the peer selection process and propose a generic model that encompasses a large class of algorithms. The process is modeled as a combination of two functions, an aware one and an agnostic one. By means of simulations, we analyze the awareness-agnostism trade-offs on the peer selection process and the impact of the source distribution policy in non-homogeneous networks. We highlight that the early diffusion of a given chunk is crucial for its overall diffusion performance, and a fairness trade-off arises between the performance of heterogeneous peers, as a function of the level of awareness

Early Experiences in Traffic Engineering Exploiting Path Diversity: A Practical Approach

Recent literature has proved that stable dynamic routing algorithms have solid theoretical foundation that makes them suitable to be implemented in a real protocol, and used in practice in many different operational network contexts. Such algorithms inherit much of the properties of congestion controllers implementing one of the possible combination of AQM/ECN schemes at nodes and flow control at sources. In this paper we propose a linear program formulation of the multi-commodity flow problem with congestion control, under max-min fairness, comprising demands with or without exogenous peak rates. Our evaluations of the gain, using path diversity, in scenarios as intra-domain traffic engineering and wireless mesh networks encourages real implementations, especially in presence of hot spots demands and non uniform traffic matrices. We propose a flow aware perspective of the subject by using a natural multi-path extension to current congestion controllers and show its performance with respect to current proposals. Since flow aware architectures exploiting path diversity are feasible, scalable, robust and nearly optimal in presence of flows with exogenous peak rates, we claim that our solution rethinked in the context of realistic traffic assumptions performs as better as an optimal approach with all the additional benefits of the flow aware paradigm

On Backstops and Boomerangs: Environmental R&D under Technological Uncertainty

The literature on environmental R&D frequently studies innovation as a two-stage process, with a single R&D event leading from a conventional polluting technology to a perfectly clean backstop. We allow for uncertainty in innovation in that the new technology may turn out to generate a new pollution problem. R&D may therefore be optimally undertaken more than once. Using and externding recent results from multi-stage optimal control theory, we provide a full characterization of the optimal pollution and R&D policies. The optimal R&D program is strictly sequential and has an endogenous stopping point. Uncertainty drives total R&D effort and its timing.stock pollution, backstop technology, multi-stage optimal control, pollution thresholds, uncertainty

Size Does Matter (in P2P Live Streaming)

Optimal dissemination schemes have previously been studied for peer-to-peer live streaming applications. Live streaming being a delay-sensitive application, fine tuning of dissemination parameters is crucial. In this report, we investigate optimal sizing of chunks, the units of data exchange, and probe sets, the number peers a given node probes before transmitting chunks. Chunk size can have significant impact on diffusion rate (chunk miss ratio), diffusion delay, and overhead. The size of the probe set can also affect these metrics, primarily through the choices available for chunk dissemination. We perform extensive simulations on the so-called random-peer, latest-useful dissemination scheme. Our results show that size does matter, with the optimal size being not too small in both cases

The Rowland Clark (41RR77) Site, Red River County, Texas : Editor\u27s Introduction

The Rowland Clark (41RR77) and Dan Holdeman (41RR11) archaeological sites were excavated in the late 1970s and early 1980s by Gregory Perino of the Museum of Red River in Idabel, Oklahoma. Manuscripts on those investigations were prepared by Perino shortly after the conclusion of the work, but these were never published, remaining instead on file at the Museum of the Red River

Wave propagation in discontinuous media

Wave propagation in discontinuous media, which is of interest for design analysis of underground structures and geotechnical works in general, is studied in this paper with the scattering matrix method. This method determines the response of a system, i.e. the discontinuous medium, excited by an elastic wave. Both P, SV or SH waves can be applied to the model with any oblique angle of incidence. The scattering matrix is composed of reflection and transmission coefficients of a single joint or a set of parallel joints. The analytical solution is obtained in the frequency domain and allows one to consider multiple wave reflections between joints. Reflected and transmitted waves are calculated for one and more joints in dry or fluid filled conditions. The solutions obtained are compared with analytical and numerical solutions available in the literature or obtained independently by using the Distinct Element Metho

Lunar production of solar cells

The feasibility of manufacturing of solar cells on the moon for spacecraft applications is examined. Because of the much lower escape velocity, there is a great advantage in lunar manufacture of solar cells compared to Earth manufacture. Silicon is abundant on the moon, and new refining methods allow it to be reduced and purified without extensive reliance on materials unavailable on the moon. Silicon and amorphous silicon solar cells could be manufactured on the moon for use in space. Concepts for the production of a baseline amorphous silicon cell are discussed, and specific power levels are calculated for cells designed for both lunar and Earth manufacture