1,720,993 research outputs found
Modeling and simulation of energy-aware adaptive policies for automatic weather stations
No full textIn this paper we present a methodology to model and anal- yse from the energetic point of view energy-aware adaptive applications for sensing and communication running on top of an Automatic Weather Station (AWS). Applications are modeled as a suite of independent policies, one for each sens- ing or transmission device. A policy is a set of rules that describe the behaviour of applications. Policies are modeled independently of the actual application implementation, so that designers could evaluate the energetic feasibility of the application early in the design process of the AWS. Policies dynamically modify the sampling frequency of sensors and the transmission starting time according to the amount of energy that could be harvested from the environment and to the amount of energy stored in the battery. In order to assess the effectiveness of the modeled policies we simulated them through an energy-aware simulator for AWS systems
Simulation of Automatic Weather Stations for the Energy Estimation of Sensing and Communication Software Policies
No full textAutomatic Weather Stations (AWSs) are widely used in environmental
sensing. Often working in harsh environments,
AWSs are equipped with rechargeable batteries, energy harvesting
and meteorological sensors connected to a processing
unit where a sensing and communication policy is executed.
An optimal policy should provide the desired sensing and
communication rates, while rmly guaranteeing the survival
of the system. In this paper, we introduce a power model
for AWSs and describe a simulator based on the Stochastic
Activity Networks formalism. The simulator helps the designer
in assessing the feasibility of a given policy, taking in
consideration context information such as temperature and
solar radiation. We successfully validated the simulator with
data collected by a real-world AWS installed on an alpine
glacier. A comparison showed that the proposed simulative
approach is more accurate than analytical models based on
average power production and consumption
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Estimation of Energy Consumption for TinyOS 2.x-Based Applications
No full textThe development of energy-efficient applications for wireless sensor networks requires mechanisms and tools for run-time monitoring of energy consumption. We propose a software framework that supports energy profiling of applications for the TinyOS 2.x platform. Measurements are obtained through the insertion of software probes within the code of the operating system. As a consequence, since the APIs are not changed, the programmer is not forced to modify the code of existing applications. The technique has been validated by comparing its results with the values registered by dedicated hardware
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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