1,069 research outputs found
A quality management based on the Quality Model life cycle
Managing quality is a hard and expensive task that involves the execution and control of processes and techniques.
For a good quality management, it is important to know the current state and the objective to be
achieved. It is essential to take into account with a Quality Model that specifies the purposes of managing
quality. QuEF (Quality Evaluation Framework) is a framework to manage quality in MDWE (Model-driven
Web Engineering). This paper suggests managing quality but pointing out the Quality Model life cycle. The
purpose is to converge toward a quality continuous improvement by means of reducing effort and time.Ministerio de Ciencia e Innovación TIN2010-20057-C03-02Ministerio de Ciencia e Innovación TIN 2010-12312-EJunta de Andalucía TIC-578
Stability and decay of Bloch oscillations in presence of time-dependent nonlinearity
We consider Bloch oscillations of Bose-Einstein condensates in presence of a
time-modulated s-wave scattering length. Generically, interaction leads to
dephasing and decay of the wave packet. Based on a cyclic-time argument, we
find---additionally to the linear Bloch oscillation and a rigid soliton
solution---an infinite family of modulations that lead to a periodic time
evolution of the wave packet. In order to quantitatively describe the dynamics
of Bloch oscillations in presence of time-modulated interactions, we employ two
complementary methods: collective-coordinates and the linear stability analysis
of an extended wave packet. We provide instructive examples and address the
question of robustness against external perturbations.Comment: 15 pages, 8 figures. Slightly amended final versio
Electron dynamics in intentionally disordered semiconductor superlattices
We study the dynamical behavior of disordered quantum-well-based
semiconductor superlattices where the disorder is intentional and short-range
correlated. We show that, whereas the transmission time of a particle grows
exponentially with the number of wells in an usual disordered superlattice for
any value of the incident particle energy, for specific values of the incident
energy this time increases linearly when correlated disorder is included. As
expected, those values of the energy coincide with a narrow subband of extended
states predicted by the static calculations of Dom\'{\i}nguez-Adame {\em et
al.} [Phys. Rev. B {\bf 51}, 14 ,359 (1994)]; such states are seen in our
dynamical results to exhibit a ballistic regime, very close to the WKB
approximation of a perfect superlattice. Fourier transform of the output signal
for an incident Gaussian wave packet reveals a dramatic filtering of the
original signal, which makes us confident that devices based on this property
may be designed and used for nanotechnological applications. This is more so in
view of the possibility of controllingthe outp ut band using a dc electric
field, which we also discuss. In the conclusion we summarize our results and
present an outlook for future developments arising from this work.Comment: 10 pagex, RevTex, 13 Postscript figures. Physical Review B (in press
Tumores en ganado ovino sacrificado en matadero
Trabajo presentado al: XL Congreso Nacional y el XVI Congreso Internacional de la Sociedad Española de Ovinotecnia y Caprinotecnia. (Castellón de la Plana, España, 16-18 septiembre 2015).Peer Reviewe
Towards the Quality Improvement of Web Applications by Neuroscience Techniques
User-centered design not only requires designers to analyse and anticipate how users are likely to use a Web application, but also to validate their assumptions with regard to user behaviour in real environments. Cognitive neuroscience, for its part, addresses the questions of how psychological functions are produced by neural circuitry. The emergence of powerful new measurement techniques
allows neuroscientists and psychologists to address abstract questions such as how human cognition and emotion are mapped to specific neural substrates. This paper focus on the validation of user-centered designs and requirements of Web applications by neuroscience techniques and suggest the use of these
techniques to achieve efficient and effectiveness validated designs by real behavior of potential users.Ministerio de Ciencia e Innovación TIN2013-46928-C3-3-RJunta de Andalucía TIC-578
Synthesis and Phytotoxicity of 4,5 Functionalized Tetrahydrofuran-2-ones
In this work we report a versatile synthesis of fourteen γ-lactones all structurally related, nine of which are novel compounds, accomplished from the readily available furfural. The phytotoxic activity of the synthesized compounds was evaluated in vitro by the influence on the growth of wheat coleoptiles. The percentages of inhibition were mostly small and not statistically different from control after the third dilution (100 μmol L-1). In general, α,β-unsaturated lactones presented better activities than the saturated ones. The most active compounds presented 51, 68 and 76% of inhibition in 1000 µmol L-1. The results indicate that regardless of saturation, the presence of the γ-lactone moiety is important for the bioactivity, but their presence has no implications with potency
Quality evaluation for Model-Driven Web Engineering methodologies
Context: There are lots of approaches or methodologies in the Model-Driven Web Engineering (MDWE)
context to develop Web Applications without reaching a consensus on the use of standards and scarcity
of both, practical experience and tool support.
Objective: Model-Driven Web Engineering (MDWE) methodologies are constantly evolving. Moreover,
Quality is a very important factor to identify within a methodology as it defines processes, techniques
and artifacts to develop Web Applications. For this reason, when analyzing a methodology, it is not only
necessary to evaluate quality, but also to find out how to improve it. The main goal of this paper is to
develop a set of Quality Characteristics and Sub-Characteristics for MDWE approaches based on ISO/
IEC standards.
Method: From the software products context, some widely standards proposed, such as ISO/IEC 9126 or
ISO/IEC 25000, suggest a Quality Model for software products, although up to now, there are no standard
methods to assess quality on MDWE methodologies. Such methodologies can be organized into Properties,
thus, a methodology has artifacts, processes and techniques. Then, each item is evaluated through a
set of appropriate Quality Characteristics, depending on its nature. This paper proposes to evaluate a
methodology as a product itself.
Results: This paper recommends a set of Quality Characteristics and Sub-Characteristics based on these
standards in order to evaluate MDWE methodologies quality. Additionally, it defines an agile way to
relate these Quality Sub-Characteristics to Properties with the sole purpose of not only analyzing, but also
assessing and improving MDWE methodologies.
Conclusions: The application of these Quality Characteristics and Sub-Characteristics could promote efficiency
in methodologies since this kind of assessment enhances both the understanding of strengths and
weaknesses of approaches.Ministerio de Educación y Ciencia TIN2007-67843-C06-03Ministerio de Educación y Ciencia TIN2010-20057-C03-0
Lump solitons in a higher-order nonlinear equation in 2+1 dimensions
We propose and examine an integrable system of nonlinear equations that generalizes the nonlinear Schrodinger equation to 2 + 1 dimensions. This integrable system of equations is a promising starting point to elaborate more accurate models in nonlinear optics and molecular systems within the continuum limit. The Lax pair for the system is derived after applying the singular manifold method. We also present an iterative procedure to construct the solutions from a seed solution. Solutions with one-, two-, and three-lump solitons are thoroughly discussed
Dynamical phenomena in Fibonacci Semiconductor Superlattices
We present a detailed study of the dynamics of electronic wavepackets in
Fibonacci semiconductor superlattices, both in flat band conditions and subject
to homogeneous electric fields perpendicular to the layers. Coherent
propagation of electrons is described by means of a scalar Hamiltonian using
the effective-mass approximation. We have found that an initial Gaussian
wavepacket is filtered selectively when passing through the superlattice. This
means that only those components of the wavepacket whose wavenumber belong to
allowed subminibands of the fractal-like energy spectrum can propagate over the
entire superlattice. The Fourier pattern of the transmitted part of the
wavepacket presents clear evidences of fractality reproducing those of the
underlying energy spectrum. This phenomenon persists even in the presence of
unintentional disorder due to growth imperfections. Finally, we have
demonstrated that periodic coherent-field induced oscillations (Bloch
oscillations), which we are able to observe in our simulations of periodic
superlattices, are replaced in Fibonacci superlattices by more complex
oscillations displaying quasiperiodic signatures, thus sheding more light onto
the very peculiar nature of the electronic states in these systems.Comment: 7 pagex, RevTex, 5 Postscript figures. Physical Review B (in press
Entity reconciliation in big data sources: A systematic mapping study
The entity reconciliation (ER) problem aroused much interest as a research topic in today’s Big Dataera, full of big and open heterogeneous data sources. This problem poses when relevant information ona topic needs to be obtained using methods based on: (i) identifying records that represent the samereal world entity, and (ii) identifying those records that are similar but do not correspond to the samereal-world entity. ER is an operational intelligence process, whereby organizations can unify differentand heterogeneous data sources in order to relate possible matches of non-obvious entities. Besides, thecomplexity that the heterogeneity of data sources involves, the large number of records and differencesamong languages, for instance, must be added. This paper describes a Systematic Mapping Study (SMS) ofjournal articles, conferences and workshops published from 2010 to 2017 to solve the problem describedbefore, first trying to understand the state-of-the-art, and then identifying any gaps in current research.Eleven digital libraries were analyzed following a systematic, semiautomatic and rigorous process thathas resulted in 61 primary studies. They represent a great variety of intelligent proposals that aim tosolve ER. The conclusion obtained is that most of the research is based on the operational phase asopposed to the design phase, and most studies have been tested on real-world data sources, where a lotof them are heterogeneous, but just a few apply to industry. There is a clear trend in research techniquesbased on clustering/blocking and graphs, although the level of automation of the proposals is hardly evermentioned in the research work.Ministerio de Economía y Competitividad TIN2013-46928-C3-3-RMinisterio de Economía y Competitividad TIN2016-76956-C3-2-RMinisterio de Economía y Competitividad TIN2015-71938-RED
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