Polytechnic University of Turin

About: Polytechnic University of Turin is a education organization based out in Turin, Piemonte, Italy. It is known for research contribution in the topics: Finite element method & Computer science. The organization has 11553 authors who have published 41395 publications receiving 789320 citations. The organization is also known as: POLITO & Politecnico di Torino.

Randomized consensus algorithms over large scale networks

Abstract: Suppose we have a directed graph G with set of nodes V = {1,...,N} and a measure xi for every node i euro V. The average consensus problem consists in computing the average xA= N-1Sigmai xi in an iterative way, exchanging information among nodes exclusively along the available edges in G. This problem appears in a number of different contexts since the 80's (decentralized computation, load balancing, clock syncronization) and, recently, has attracted much attention for possible applications to sensor networks (data fusion problems) and to coordinated control for mobile autonomous agents. Several algorithms for average consensus can be found in the literature: they differentiate on the basis of the amount of communication and computation they use, on their scalability with respect to the number of nodes, on their adaptability to time-varying graphs, and, finally, they can be deterministic or random. In this presentation we will focus on random algorithms: we will review some algorithms present in the literature and we will propose some new ones. We will present some performance results which will allow to make some comparison. Finally, we will establish some probabilistic concentration results which will give a stronger significance to previous results.

The Demand Elasticity Impacts on the Strategic Bidding Behavior of the Electricity Producers

Abstract: Due to the oligopoly structure of the electricity markets and to the constraints imposed by the transmission network, the producers may exert market power by strategically bidding higher than their marginal costs. This brings market performance far from the perfect competition equilibrium, with higher market clearing price and extra surpluses obtained by the producers. Demand elasticity can significantly affect the market performance contributing to mitigate the strategic bidding behavior of the producers. Compared to other commodity markets, demand elasticity in the electricity markets is low, but even a small increase can result in appreciable improvement of the market performance. The network constraints of the power system play a specific role in determining the oligopoly equilibrium of the gaming behavior of the electricity producers. The model of supply function equilibrium is first applied to a simple three-bus test system for a conceptual analysis and then to a standard IEEE 30-bus test system. The effects of an increase of demand elasticity are assessed, resorting to a set of proper quantitative indexes

InP based lasers and optical amplifiers with wire-/dot-like active regions

Abstract: Long wavelength lasers and semiconductor optical amplifiers based on InAs quantum wire-/dot-like active regions were developed on InP substrates dedicated to cover the extended telecommunication wavelength range between 1.4 and 1.65 µm. In a brief overview different technological approaches will be discussed, while in the main part the current status and recent results of quantum-dash lasers are reported. This includes topics like dash formation and material growth, device performance of lasers and optical amplifiers, static and dynamic properties and fundamental material and device modelling. (Some figures in this article are in colour only in the electronic version)

Transient analysis of lossy transmission lines: an efficient approach based on the method of Characteristics

Abstract: This paper is devoted to transient analysis of lossy transmission lines characterized by frequency-dependent parameters. A public dataset of parameters for three line examples (a module, a board, and a cable) is used, and a new example of on-chip interconnect is introduced. This dataset provides a well established and realistic benchmark for accuracy and timing analysis of interconnect analysis tools. Particular attention is devoted to the intrinsic consistency and causality of these parameters. Several implementations based on generalizations of the well-known method-of-characteristics are presented. The key feature of such techniques is the extraction of the line modal delays. Therefore, the method is highly optimized for long interconnects characterized by significant propagation delay. Nonetheless, the method is also successfully applied here to a short high/loss on-chip line, for which other approaches based on lumped matrix rational approximations can also be used with high efficiency. This paper shows that the efficiency of delay extraction techniques is strongly dependent on the particular circuit implementation and several practical issues including generation of rational approximations and time step control are discussed in detail.