9,540 research outputs found
Economic Voting in Portuguese Municipal Elections
This paper analyses the impact of economic conditions on Portuguese local electoral outcomes. We use two extensive datasets to estimate an economic voting model which accounts for the possibility that different levels of government have different levels of responsibility for economic outcomes and for clarity of government responsibility. Empirical results indicate that the performance of the national economy is important especially if local governments are of the same party as the central government. The municipal situation is also relevant particularly in scenarios of higher clarity of government responsibilityLocal governments, Elections, Portugal, Voting, Economic conditions
Turnout and the modeling of economic conditions: Evidence from Portuguese elections
This paper analyzes the impact of economic conditions on voter turnout at Portuguese legislative and municipal elections. We use four extensive datasets to estimate an economic turnout model in which local economic variables are included in quadratic form, so that non-linear effects can be taken into account. The first two datasets cover all mainland municipalities (currently 278), from 1979 to 2005. The other two are cross-sections of all 4037 mainland freguesias, used to analyze the determinants of turnout at the 2001 municipal elections and at the 2002 legislative elections. Empirical results indicate that the performance of the national economy is important only in legislative elections and that, in accordance with our expectations, the regional and local unemployment rates tend to have a non-linear relationship with turnout.Turnout, Local governments, Elections, Portugal, Economic conditions
Economic Voting in Portuguese Municipal Elections
This paper analyses the impact of economic conditions on Portuguese local electoral outcomes. We use two extensive datasets to estimate an economic voting model which accounts for the possibility that different levels of government have different levels of responsibility for economic outcomes and for clarity of government responsibility. Empirical results indicate that the performance of the national economy is important especially if local governments are of the same party as the central government. The municipal situation is also relevant particularly in scenarios of higher clarity of government responsibility.Local governments, Elections, Portugal, Voting, Economic conditions
Characterizing and attributing the warming trend in sea and land surface temperatures
Because of low-frequency internal variability, the observed and underlying warming trends in temperature series can be markedly different. Important differences in the observed nonlinear trends in hemispheric temperature series suggest that the northern and southern hemispheres have responded differently to the changes in the radiative forcing. Using recent econometric techniques, we can reconcile such differences and show that all sea and land temperatures share similar time series properties and a common underlying warming trend having a dominant anthropogenic origin. We also investigate the interhemispheric temperature asymmetry (ITA) and show that the differences in warming between hemispheres are in part driven by anthropogenic forcing but that most of the observed rapid changes is likely due to natural variability. The attribution of changes in ITA is relevant since increases in the temperature contrast between hemispheres could potentially produce a shift in the Intertropical Convergence Zone and alter rainfall patterns. The existence of a current slowdown in the warming and its causes are also investigated. The results suggest that the slowdown is a common feature in global and hemispheric sea and land temperatures that can, at least partly, be attributed to changes in anthropogenic forcing.Debido a la variabilidad interna de baja frecuencia, las tendencias del calentamiento observadas y subyacentes en series de temperatura pueden ser marcadamente diferentes. Las temperaturas hemisfĂ©ricas estĂĄn caracterizadas por importantes discrepancias en las tendencias no lineales observadas, sugiriendo que los hemisferios norte y sur han respondido de manera diferente a los cambios en el forzamiento radiativo. Mediante la utilizaciĂłn de tĂ©cnicas economĂ©tricas recientes es posible reconciliar estas diferencias y mostrar que todas las temperaturas terrestres y oceĂĄnicas comparten propiedades de series de tiempo similares, asĂ como una tendencia subyacente comĂșn de origen antrĂłpico. TambiĂ©n se investiga la asimetrĂa inter-hemisfĂ©rica de temperatura (ITA, por sus siglas en inglĂ©s) y se muestra que la diferencia en el calentamiento entre hemisferios se debe en parte al forzamiento antrĂłpico, pero que la mayorĂa de los cambios rĂĄpidos observados son probablemente producto de la variabilidad natural. La atribuciĂłn de cambios en la ITA es importante porque los aumentos en el contraste de temperaturas entre hemisferios podrĂan ocasionar un desplazamiento de la zona intertropical de convergencia y alterar los patrones de precipitaciĂłn. TambiĂ©n se investigan la existencia y causas de una reciente ralentizaciĂłn en el calentamiento. Los resultados sugieren que dicha lentificaciĂłn es una caracterĂstica comĂșn de las temperaturas hemisfĂ©ricas globales tanto en tierra como en el ocĂ©ano, y que puede atribuirse al menos parcialmente a cambios en el forzamiento antrĂłpico
Types for X10 Clocks
X10 is a modern language built from the ground up to handle future parallel
systems, from multicore machines to cluster configurations. We take a closer
look at a pair of synchronisation mechanisms: finish and clocks. The former
waits for the termination of parallel computations, the latter allow multiple
concurrent activities to wait for each other at certain points in time. In
order to better understand these concepts we study a type system for a stripped
down version of X10. The main result assures that well typed programs do not
run into the errors identified in the X10 language reference, namely the
ClockUseException. The study will open, we hope, doors to a more flexible
utilisation of clocks in the X10 language.Comment: In Proceedings PLACES 2010, arXiv:1110.385
Deductive Verification of Parallel Programs Using Why3
The Message Passing Interface specification (MPI) defines a portable
message-passing API used to program parallel computers. MPI programs manifest a
number of challenges on what concerns correctness: sent and expected values in
communications may not match, resulting in incorrect computations possibly
leading to crashes; and programs may deadlock resulting in wasted resources.
Existing tools are not completely satisfactory: model-checking does not scale
with the number of processes; testing techniques wastes resources and are
highly dependent on the quality of the test set.
As an alternative, we present a prototype for a type-based approach to
programming and verifying MPI like programs against protocols. Protocols are
written in a dependent type language designed so as to capture the most common
primitives in MPI, incorporating, in addition, a form of primitive recursion
and collective choice. Protocols are then translated into Why3, a deductive
software verification tool. Source code, in turn, is written in WhyML, the
language of the Why3 platform, and checked against the protocol. Programs that
pass verification are guaranteed to be communication safe and free from
deadlocks.
We verified several parallel programs from textbooks using our approach, and
report on the outcome.Comment: In Proceedings ICE 2015, arXiv:1508.0459
Assessing the Number of Components in Mixture Models: a Review.
Despite the widespread application of finite mixture models, the decision of how many classes are required to adequately represent the data is, according to many authors, an important, but unsolved issue. This work aims to review, describe and organize the available approaches designed to help the selection of the adequate number of mixture components (including Monte Carlo test procedures, information criteria and classification-based criteria); we also provide some published simulation results about their relative performance, with the purpose of identifying the scenarios where each criterion is more effective (adequate).Finite mixture; number of mixture components; information criteria; simulation studies.
Using Generic Summarization to Improve Music Information Retrieval Tasks
In order to satisfy processing time constraints, many MIR tasks process only
a segment of the whole music signal. This practice may lead to decreasing
performance, since the most important information for the tasks may not be in
those processed segments. In this paper, we leverage generic summarization
algorithms, previously applied to text and speech summarization, to summarize
items in music datasets. These algorithms build summaries, that are both
concise and diverse, by selecting appropriate segments from the input signal
which makes them good candidates to summarize music as well. We evaluate the
summarization process on binary and multiclass music genre classification
tasks, by comparing the performance obtained using summarized datasets against
the performances obtained using continuous segments (which is the traditional
method used for addressing the previously mentioned time constraints) and full
songs of the same original dataset. We show that GRASSHOPPER, LexRank, LSA,
MMR, and a Support Sets-based Centrality model improve classification
performance when compared to selected 30-second baselines. We also show that
summarized datasets lead to a classification performance whose difference is
not statistically significant from using full songs. Furthermore, we make an
argument stating the advantages of sharing summarized datasets for future MIR
research.Comment: 24 pages, 10 tables; Submitted to IEEE/ACM Transactions on Audio,
Speech and Language Processin
On the Application of Generic Summarization Algorithms to Music
Several generic summarization algorithms were developed in the past and
successfully applied in fields such as text and speech summarization. In this
paper, we review and apply these algorithms to music. To evaluate this
summarization's performance, we adopt an extrinsic approach: we compare a Fado
Genre Classifier's performance using truncated contiguous clips against the
summaries extracted with those algorithms on 2 different datasets. We show that
Maximal Marginal Relevance (MMR), LexRank and Latent Semantic Analysis (LSA)
all improve classification performance in both datasets used for testing.Comment: 12 pages, 1 table; Submitted to IEEE Signal Processing Letter
Azores tourism product perceptions : the Influence of the country of origin
This study focused on the Autonomous Region of the Azores (ARA), which has some features that are considered favorable to the development of tourism and to the interest in the tourism product. However, the regionâs geographical dispersion, its high dependence on transportation and the seasonality of the industry constrain its development.
The present research aimed to assess touristsâ perception of certain costs (living, accommodation, plane ticket, and transportation to/from the airport), and whether these differ between tourists of different nationalities.
The findings show that tourists, both residents and non-residents, have the perception that the cost of living and of the plane ticket are high, while the cost of accommodation and of transportation to the airport is considered normal by most respondents.
We concluded that the models differ when applied to residents and non-residents. For non-residents, living in certain countries induces them to express differences in the perception of the costs studied, when compared to individuals that live in other countries.N/
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