63,595 research outputs found
A note on selecting maximals in finite spaces
Given a choice problem, the maximization rule may select many alternatives. In such
cases, it is common practice to interpret that the final choice will end up being made by
some random procedure, assigning to any maximal alternative the same probability of
being chosen. However, there may be reasons based on the same original preferences
for which it is suitable to select certain maximal alternatives over others. This paper
introduces two choice criteria induced by the original preferences such that maximizing
with respect to each of them may give a finer selection of alternatives than maximizing
with respect to the original preferences. Those criteria are built by means of several
preference relations induced by the original preferences, namely, two (weak) dominance
relations, two indirect preference relations and the dominance relations defined with the
help of those indirect preferences. It is remarkable that as the original preferences
approach being complete and transitive, those criteria become both simpler and closer to
such preferences. In particular, they coincide with the original preferences when these
are complete and transitive, in which case they provide the same solution as those
preference
A characterization of some families of Cohen--Macaulay, Gorenstein and/or Buchsbaum rings
We provide algorithmic methods to check the Cohen--Macaulayness,
Buchsbaumness and/or Gorensteiness of some families of semigroup rings that are
constructed from the dilation of bounded convex polyhedrons of .
Some families of semigroup rings are given satifying these properties
Teaching-innovation experience in competitiveness and innovation in business
The aim of this paper is to contrast the students’ opinions about the teaching innovation experience carried out in the subject “Competitividad en Innovación en la Empresa” (Competitiveness and Innovation in Business). The procedure will start with the subject’s profile, going through the main objectives and teaching methodology, to finish with evaluation and assessment, as suggested in the subject’s syllabus for the academic year 2007/08. Taking this as a starting point and, due to the fact that the number of students in the control group is not very high, we suggest changing both the teaching methodology and the evaluation. These changes will be contrasted with the students’ acceptance and involvement.PROCEEDINGS C
Technocracy inside the rule of law : challenges in the foundations of legal norms
Technocracy is usually opposed to democracy. Here, another perspective is taken: technocracy is countered with the rule of law. In trying to understand the contemporary dynamics of the rule of law, two main types of legal systems (in a broad sense) have to be distinguished: firstly, the legal norm, studied by the science of law; secondly, the scientific laws (which includes the legalities of the different sciences and communities). They both contain normative prescriptions. But their differ in their subjects‘ source: while legal norms are the will’s expression of the normative authority, technical prescriptions can be derived from scientific laws, which are grounded over the commonly supposed objectivity of the scientific knowledge about reality. They both impose sanctions too, but in the legal norm they refer to what is established by the norm itself, while in the scientific legality they consist in the reward or the punishment derived from the efficacy or inefficacy to reach the end pursued by the action. The way of legitimation also differs: while legal norms have to have followed the formal procedures and must not have contravened any fundamental right, technical norms‘ validity depend on its theoretical foundations or on its efficacy. Nowadays, scientific knowledge has become and important feature in policy-making. Contradictions can arise between these legal systems. These conflicts are specially grave when the recognition or exercise of fundamental rights is instrumentally used, or when they are violated in order to increase the policies‘ efficacy. A political system is technocratic, when, in case of contradiction, the scientific law finally prevails
A non-proposition-wise variant of majority voting for aggregating judgments
Majority voting is commonly used in aggregating judgments. The literature to date on judgment
aggregation (JA) has focused primarily on proposition-wise majority voting (PMV). Given a set of issues
on which a group is trying to make collective judgments, PMV aggregates individual judgments issue by
issue, and satisfies a salient property of JA rules—independence. This paper introduces a variant of
majority voting called holistic majority voting (HMV). This new variant also meets the condition of
independence. However, instead of aggregating judgments issue by issue, it aggregates individual
judgments en bloc. A salient and straightforward feature of HMV is that it guarantees the logical
consistency of the propositions expressing collective judgments, provided that the individual points of
view are consistent. This feature contrasts with the known inability of PMV to guarantee the consistency
of the collective outcome. Analogously, while PMV may present a set of judgments that have been
rejected by everyone in the group as collectively accepted, the collective judgments returned by HMV
have been accepted by a majority of individuals in the group and, therefore, rejected by a minority of
them at most. In addition, HMV satisfies a large set of appealing properties, as PMV also does. However,
HMV may not return any complete proposition expressing the judgments of the group on all the issues at
stake, even in cases where PMV does. Moreover, demanding completeness from HMV leads to
impossibility results similar to the known impossibilities on PMV and on proposition-wise JA rules in
genera
Detecting the gravitational wave background from primordial black hole dark matter
The black hole merging rates inferred after the gravitational-wave detection
by Advanced LIGO/VIRGO and the relatively high mass of the progenitors are
consistent with models of dark matter made of massive primordial black holes
(PBH). PBH binaries emit gravitational waves in a broad range of frequencies
that will be probed by future space interferometers (LISA) and pulsar timing
arrays (PTA). The amplitude of the stochastic gravitational-wave background
expected for PBH dark matter is calculated taking into account various effects
such as initial eccentricity of binaries, PBH velocities, mass distribution and
clustering. It allows a detection by the LISA space interferometer, and
possibly by the PTA of the SKA radio-telescope. Interestingly, one can
distinguish this background from the one of non-primordial massive binaries
through a specific frequency dependence, resulting from the maximal impact
parameter of binaries formed by PBH capture, depending on the PBH velocity
distribution and their clustering properties. Moreover, we find that the
gravitational wave spectrum is boosted by the width of PBH mass distribution,
compared with that of the monochromatic spectrum. The current PTA constraints
already rule out broad-mass PBH models covering more than three decades of
masses, but evading the microlensing and CMB constraints due to clustering.Comment: 12 pages, 4 figure
Cosmic troublemakers: the Cold Spot, the Eridanus Supervoid, and the Great Walls
The alignment of the CMB Cold Spot and the Eridanus supervoid suggests a
physical connection between these two relatively rare objects. We use galaxy
cata\-logues with photometric (2MPZ) and spectroscopic (6dF) redshift
measurements, supplemented by low-redshift compilations of cosmic voids, in
order to improve the 3D mapping of the matter density in the Eridanus
constellation. We find evidence for a supervoid with a significant elongation
in the line-of-sight, effectively spanning the total redshift range .
Our tomographic imaging reveals important substructure in the Eridanus
supervoid, with a potential interpretation of a long, fully connected system of
voids. We improve the analysis by extending the line-of-sight measurements into
the antipodal direction that interestingly crosses the Northern Local Supervoid
at the lowest redshifts. Then it intersects very rich superclusters like
Hercules and Corona Borealis, in the region of the Coma and Sloan Great Walls,
as a possible compensation for the large-scale matter deficit of Eridanus. We
find that large-scale structure measurements are consistent with a central
matter underdensity , projected transverse radius
Mpc/h with an extra deepening in the centre, and
line-of-sight radius Mpc/h, i.e. an ellipsoidal
supervoid. The expected integrated Sachs-Wolfe imprint of such an elongated
supervoid is at the level, thus
inappropriate to accounting for the Cold Spot pattern in the CMB.Comment: 13 pages, 9 figures. Accepted by MNRAS in this for
Automated Functional Testing based on the Navigation of Web Applications
Web applications are becoming more and more complex. Testing such
applications is an intricate hard and time-consuming activity. Therefore,
testing is often poorly performed or skipped by practitioners. Test automation
can help to avoid this situation. Hence, this paper presents a novel approach
to perform automated software testing for web applications based on its
navigation. On the one hand, web navigation is the process of traversing a web
application using a browser. On the other hand, functional requirements are
actions that an application must do. Therefore, the evaluation of the correct
navigation of web applications results in the assessment of the specified
functional requirements. The proposed method to perform the automation is done
in four levels: test case generation, test data derivation, test case
execution, and test case reporting. This method is driven by three kinds of
inputs: i) UML models; ii) Selenium scripts; iii) XML files. We have
implemented our approach in an open-source testing framework named Automatic
Testing Platform. The validation of this work has been carried out by means of
a case study, in which the target is a real invoice management system developed
using a model-driven approach.Comment: In Proceedings WWV 2011, arXiv:1108.208
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