1,720,991 research outputs found
A Point Pattern Network Density Algorithm
No full textThe aim of this paper is to consider point pattern distributions over a network considering network spaces as structures for the distribution of point patterns.
The term point pattern analysis indicates a set of methods used both in Spatial Analysis and Geographical Information Science to analyze the properties of distributions of points in a space.
From a statistical point of view, an observed spatial point pattern can be thought as the outcome of a spatial stochastic process. Useful aspects of the behaviour of a general spatial stochastic process may be characterized by its first order properties, described in terms of the mean number of events per unit area at a certain point , and by its second order properties or spatial dependence which involve the relationship between numbers of event in pairs of subregions within R.
In this paper we present an extension of the Kernel Density Estimation (KDE), called Point Pattern Network Density Estimation (PPNDE). Circular clusters of points distributed in the geographical space may be found by using Kernel Density Estimation; other configurations of cluster of points, depending on the network space, are also possible. In order to take into account this possibility the idea is to consider the kernel function as a density function based on network distances rather than on the Euclidean one.
Some simulation experiments and an experiment based on a real data set end the paper
Emerging Models for Corporate Welfare and HR Management in the Service-Dominant Logic. Mediterranean Conference on Information Systems (MCIS 2014), Università di Verona
No full textSocial capital and its effect on networked firm innovation and competitiveness
Full text linkInternational and local policymakers have repeatedly encouraged the development of clusters -a dense geographic concentration of interconnected businesses- to boost competitiveness at both the firm and regional levels, as well as foster innovation and new product development. Following this trend, many initiatives have started to provide services and infrastructure that can facilitate the establishment of formal and informal ties between firms, local institutions or research centres, as well as upgrade the stock of human and intellectual capital. In this scenario, the present study empirically documents the effects of an innovation network, established by a regional government institution, on the participating firms. In particular, firm-level primary data, derived from the participants of 'Polo di Innovazione ICT - Abruzzo' in Italy, empirically support how the cognitive, structural and relational dimensions of the social capital developed within a cluster initiative affect the performance of participating firms, unveiling a negative moderation effect arising from firms' involvement in the cluster program
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
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
Cytotoxic and genotoxic potential of drinking water: a comparison between two different concentration methods.
No full textThe level of exposure to hazardous compounds through drinking water is low but it is maintained throughout
life, therefore representing a risk factor for human health. The use of techniques averaging the consumer's
exposure over time could be more useful than relying on intermittent grab samples that may misrepresent
average tap water concentrations due to short-term temporal variability. In this study, we compared the
induction of in vitro cytotoxic and genotoxic effects (DNA damage by the comet assay) in relation to different
sampling methods, i.e. exposure over time (semipermeable membrane devices, SPMDs, exposed for 30
days) or intermittent grab samples (5 weekly water sampling, C18 concentration). Waters with different
chemical characteristics were sampled to test the sensitivity of the two methods. We did not found any
positive correlation between the biological findings and water chemical parameters. SPMD extracts induced
a significantly greater DNA damage than C18. The different behaviour was specially found for the water
samples with a low level of organic compounds and when C18 extracts were highly cytotoxic. Our findings
suggest that SPMD could be of a great interest in assessing genotoxic contaminants in both raw and
drinking water, with great suitability for continuous monitoring. Furthermore, the results of this study have
confirmed the great importance of the biological assays in evaluating the effects of a complex mixture such
as water in addition to the conventional chemical examination of water quality
- …
