83,938 research outputs found
Energy-efficient wireless communication
In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters
Bargaining Mechanisms for One-Way Games
We introduce one-way games, a framework motivated by applications in
large-scale power restoration, humanitarian logistics, and integrated
supply-chains. The distinguishable feature of the games is that the payoff of
some player is determined only by her own strategy and does not depend on
actions taken by other players. We show that the equilibrium outcome in one-way
games without payments and the social cost of any ex-post efficient mechanism,
can be far from the optimum. We also show that it is impossible to design a
Bayes-Nash incentive-compatible mechanism for one-way games that is
budget-balanced, individually rational, and efficient. To address this negative
result, we propose a privacy-preserving mechanism that is incentive-compatible
and budget-balanced, satisfies ex-post individual rationality conditions, and
produces an outcome which is more efficient than the equilibrium without
payments. The mechanism is based on a single-offer bargaining and we show that
a randomized multi-offer extension brings no additional benefit.Comment: An earlier, shorter version of this paper appeared in Proceedings of
the Twenty-Fourth International joint conference on Artificial Intelligence
(IJCAI) 201
Heliostat field cleaning scheduling for Solar Power Tower plants: a heuristic approach
Soiling of heliostat surfaces due to local climate has a direct impact on their
optical efficiency and therefore a direct impact on the productivity of the Solar
Power Tower plant. Cleaning techniques applied are dependent on plant construction and current schedules are normally developed considering heliostat layout patterns, providing sub-optimal results. In this paper, a method to optimise cleaning schedules is developed, with the objective of maximising energy generated by the plant. First, an algorithm finds a cleaning schedule by solving an integer program, which is then used as a starting solution in an exchange heuristic. Since the optimisation problems are of large size, a p-median type heuristic is performed to reduce the problem dimensionality by clustering heliostats into groups to be cleaned in the same period.Ministerio de EconomĂa y Competitivida
An efficient -means-type algorithm for clustering datasets with incomplete records
The -means algorithm is arguably the most popular nonparametric clustering
method but cannot generally be applied to datasets with incomplete records. The
usual practice then is to either impute missing values under an assumed
missing-completely-at-random mechanism or to ignore the incomplete records, and
apply the algorithm on the resulting dataset. We develop an efficient version
of the -means algorithm that allows for clustering in the presence of
incomplete records. Our extension is called -means and reduces to the
-means algorithm when all records are complete. We also provide
initialization strategies for our algorithm and methods to estimate the number
of groups in the dataset. Illustrations and simulations demonstrate the
efficacy of our approach in a variety of settings and patterns of missing data.
Our methods are also applied to the analysis of activation images obtained from
a functional Magnetic Resonance Imaging experiment.Comment: 21 pages, 12 figures, 3 tables, in press, Statistical Analysis and
Data Mining -- The ASA Data Science Journal, 201
Auctioning airport slots (?)
The current allocation of slots on congested European airports constitutes an obstacle to the effective liberalisation of air transportation undertaken in Europe. With a view to favouring efficient slot utilisation and competition, as is the goal of the European commission, we propose to use a market mechanism, based on temporary utilisation licences. In order to allocate those licences, we propose and describe an iterated combinatorial auction mechanism where a percentage of licences would be reallocated each season. A secondary market would also be set up in order to reallocate slots during a season. Since a combinatorial auction involve a complex optimisation procedure, we describe how it can be made to work in the case of auctions.slots; airports; licence; auction; combinatorial
Global sensitivity analysis of the single particle lithium-ion battery model with electrolyte
The importance of global sensitivity analysis (GSA) has been well established in many scientific areas. However, despite its critical role in evaluating a model’s plausibility and relevance, most lithium ion battery models are published without any sensitivity analysis. In order to improve the lifetime performance of battery packs, researchers are investigating the application of physics based electrochemical models, such as the single particle model with electrolyte (SPMe). This is a challenging research area from both the parameter estimation and modelling perspective. One key challenge is the number of unknown parameters: the SPMe contains 31 parameters, many of which are themselves non-linear functions of other parameters. As such, relatively few authors have tackled this parameter estimation problem. This is exacerbated because there are no GSAs of the SPMe which have been published previously. This article addresses this gap in the literature and identifies the most sensitive parameter, preventing time being wasted on refining parameters which the output is insensitive to
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