Search results for "Data analysis."
showing 10 items of 377 documents
Analytical properties of horizontal visibility graphs in the Feigenbaum scenario
2012
Time series are proficiently converted into graphs via the horizontal visibility (HV) algorithm, which prompts interest in its capability for capturing the nature of different classes of series in a network context. We have recently shown [1] that dynamical systems can be studied from a novel perspective via the use of this method. Specifically, the period-doubling and band-splitting attractor cascades that characterize unimodal maps transform into families of graphs that turn out to be independent of map nonlinearity or other particulars. Here we provide an in depth description of the HV treatment of the Feigenbaum scenario, together with analytical derivations that relate to the degree di…
A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins
2018
Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The Europea…
Do firms share the same functional form of their growth rate distribution? A statistical test
2014
We introduce a new statistical test of the hypothesis that a balanced panel of firms have the same growth rate distribution or, more generally, that they share the same functional form of growth rate distribution. We applied the test to European Union and US publicly quoted manufacturing firms data, considering functional forms belonging to the Subbotin family of distributions. While our hypotheses are rejected for the vast majority of sets at the sector level, we cannot rejected them at the subsector level, indicating that homogenous panels of firms could be described by a common functional form of growth rate distribution.
An international cohort comparison of size effects on job growth
2015
The contribution of different-sized businesses to job creation continues to attract policymakers’ attention, however, it has recently been recognized that conclusions about size were confounded with the effect of age. We probe the role of size, controlling for age, by comparing the cohorts of firms born in 1998 over their first decade of life, using variation across half a dozen northern European countries Austria, Finland, Germany, Norway, Sweden, and the UK to pin down size effects. We find that a very small proportion of the smallest firms play a crucial role in accounting for cross-country differences in job growth. A closer analysis reveals that the initial size distribution and surviv…
Sustainable growth of EU economies and Baltic context: Characteristics and modelling
2017
The united general growth strategy for all EU Member States, a common economic and political vision as well as location in the same geographic region provides a necessary basis for the benchmarking modelling of economies. The main objective of this study is determination of the functional regularities and drivers of the growth of EU economies and the context of the Baltic States in line with the general trend of the EU, as well as development of the growth model, which can be used for sustainable planning and prediction. Analysis of several regularly published analytical indexes suggests a thesis on innovation as the real basic driving force for EU economies and outlines Innovation Performa…
Factors Affecting Attrition among First Year Computer Science Students: the Case of University of Latvia
2015
<p class="R-AbstractKeywords"><span lang="EN-GB">The purpose of our study was to identify reasons for high dropout of students enrolled in the first year of the computer science study program to make it possible to determine students, who are potentially in risk. Several factors that could affect attrition, as it was originally assumed, were studied: high school grades (admission score), compensative course in high school mathematics, intermediate grades for core courses, prior knowledge of programming. However, the results of our study indicate that none of the studied factors is determinant to identify those students, who are going to abandon their studies, with great precisio…
On Detection of Yaw and Roll Angle Information for Vehicle Oblique Crash using Hough Transform
2014
When performing vehicle crash tests, it is common to capture high frame rate video (HFR) to observe the vehicle motion during the impact. Such videos contain a lot of information, especially when it comes to geometric data. The yaw and roll angles from the HFR video is detected by using the Hough Transform and Matlab's Image processing Toolbox. The measured Yaw angle from the HFR video are compared with real life test data captured with a gyroscopic device inside the vehicle during the oblique vehicle impact.
Analysing the conceptions on modelling of engineering undergraduate students: A case study using cluster analysis
2016
The problem of taking a set of data and separating it into subgroups where the elements of each subgroup are more similar to each other than they are to elements not in the subgroup has been extensively studied through the statistical method of Cluster Analysis . This method can be conveniently used to separate students into groups that can be recognized and characterized by common traits in their answers, without any prior knowledge of what form those groups would take (unsupervised classification). In the last years many studies examined the consistency of students’ answers in a variety of situations. Some of these papers have tried to develop more detailed models of the consistency of st…
A Virtual Milling Machine Model to Generate Machine-Monitoring Data for Predictive Analytics
2015
Real data from manufacturing processes are essential to create useful insights for decision-making. However, acquiring real manufacturing data can be expensive and time consuming. To address this issue, we implement a virtual milling machine model to generate machine monitoring data from process plans. MTConnect is used to report the monitoring data. This paper presents (1) the characteristics and specification of milling machine tools, (2) the architecture for implementing the virtual milling machine model, and (3) the integration with a simulation environment for extending to a virtual shop floor model. This paper also includes a case study to explain how to use the virtual milling machin…
THE “ZISA” IN PALERMO: BIOCLIMATIC ASPECTS OF ITS ARCHITECTURE
2010
In the present work is examined, as an ante-litteram example of summer residence and bioclimatic archi-tecture, the ancient castle of the Zisa (from the Arabic 'al-aziz = noble, shining, glorious), meaningful work of Arab-Islamic character built up at the beginnings of the XII century (fig. 1). The building holds a notable importance as it is one of the few examples of Norman civil architecture with elements of Arab-Islamic character and Byzantian culture, but also because it had been conceived according to the most re-fined Islamic techniques of free cooling. The building (fig. 1) presents itself like a massive rectangular construction developed on three levels. On the architectural plan t…