8,006 research outputs found
Creation of the selection list for the Experiment Scheduling Program (ESP)
The efforts to develop a procedure to construct selection groups to augment the Experiment Scheduling Program (ESP) are summarized. Included is a User's Guide and a sample scenario to guide in the use of the software system that implements the developed procedures
Impact of spatially constrained sampling of temporal contact networks on the evaluation of the epidemic risk
The ability to directly record human face-to-face interactions increasingly
enables the development of detailed data-driven models for the spread of
directly transmitted infectious diseases at the scale of individuals. Complete
coverage of the contacts occurring in a population is however generally
unattainable, due for instance to limited participation rates or experimental
constraints in spatial coverage. Here, we study the impact of spatially
constrained sampling on our ability to estimate the epidemic risk in a
population using such detailed data-driven models. The epidemic risk is
quantified by the epidemic threshold of the
susceptible-infectious-recovered-susceptible model for the propagation of
communicable diseases, i.e. the critical value of disease transmissibility
above which the disease turns endemic. We verify for both synthetic and
empirical data of human interactions that the use of incomplete data sets due
to spatial sampling leads to the underestimation of the epidemic risk. The bias
is however smaller than the one obtained by uniformly sampling the same
fraction of contacts: it depends nonlinearly on the fraction of contacts that
are recorded and becomes negligible if this fraction is large enough. Moreover,
it depends on the interplay between the timescales of population and spreading
dynamics.Comment: 21 pages, 7 figure
Testing Interestingness Measures in Practice: A Large-Scale Analysis of Buying Patterns
Understanding customer buying patterns is of great interest to the retail
industry and has shown to benefit a wide variety of goals ranging from managing
stocks to implementing loyalty programs. Association rule mining is a common
technique for extracting correlations such as "people in the South of France
buy ros\'e wine" or "customers who buy pat\'e also buy salted butter and sour
bread." Unfortunately, sifting through a high number of buying patterns is not
useful in practice, because of the predominance of popular products in the top
rules. As a result, a number of "interestingness" measures (over 30) have been
proposed to rank rules. However, there is no agreement on which measures are
more appropriate for retail data. Moreover, since pattern mining algorithms
output thousands of association rules for each product, the ability for an
analyst to rely on ranking measures to identify the most interesting ones is
crucial. In this paper, we develop CAPA (Comparative Analysis of PAtterns), a
framework that provides analysts with the ability to compare the outcome of
interestingness measures applied to buying patterns in the retail industry. We
report on how we used CAPA to compare 34 measures applied to over 1,800 stores
of Intermarch\'e, one of the largest food retailers in France
Computing phonological generalization over real speech exemplars
Though it has attracted growing attention from phonologists and phoneticians Exemplar Theory (e g Bybee 2001) has hitherto lacked an explicit production model that can apply to speech signals An adequate model must be able to generalize but this presents the problem of how to generate an output that generalizes over a collection of unique variable-length signals Rather than resorting to a priori phonological units such as phones we adopt a dynamic programming approach using an optimization criterion that is sensitive to the frequency of similar subsequences within other exemplars the Phonological Exemplar-Based Learning System We show that PEBLS displays pattern-entrenchment behaviour central to Exemplar Theory s account of phonologization (C) 2010 Elsevier Ltd All rights reserve
APPROACHES TO VULNERABILITY ANALYSIS FOR DISCOVERING THE CRITICAL ROUTES IN ROADWAY NETWORKS
All modes of transportation are vulnerable to disruptions caused by natural disasters and/or man-made events (e.g., accidents), which may have temporary or permanent consequences. Identifying crucial links where failure could have significant effects is an important component of transportation network vulnerability assessments, and the risk of such occurrences cannot be underestimated. The ability to recognize critical segments in a transportation network is essential for designing resilient networks and improving traffic conditions in scenarios like link failures, which can result in partial or full capacity reductions in the system. This study proposes two approaches for identifying critical links for both single and multiple link disruptions. New hybrid link ranking measures are proposed, and their accuracy is compared with the existing traffic-based measures. These new ranking measures integrate aspects of traffic equilibrium and network topology. The numerical study revealed that three of the proposed measures generate valid findings while consuming much less computational power and time than full-scan analysis measures. To cover various disruption possibilities other than single link failure, an optimization model based on a game theory framework and a heuristic algorithm to solve the mathematical formulation is described in the second part of this research. The proposed methodology is able to identify critical sets of links under different disruption scenarios including major and minor interruptions, non-intelligent and intelligent attackers, and the effect of presenting defender. Results were evaluated with both full scan analysis techniques and hybrid ranking measures, and the comparison demonstrated that the proposed model and algorithm are reliable at identifying critical sets of links for random and specially targeted attacks based on the adversary\u27s link selection in both partial and complete link closure scenarios, while significantly reducing computational complexity. The findings indicate that identifying critical sets of links is highly dependent on the adversary\u27s inelegancy, the presence of defenders, and the disruption scenario. Furthermore, this research indicates that in disruptions of multiple links, there is a complex correlation between critical links and simply combining the most critical single links significantly underestimates the network\u27s vulnerability
EU Trade Policies: Benchmarking Protection in a General Equilibrium Framework
This paper deals with the EU’s trade policy with two objectives: on the one hand, we study the performance of EU's preferential agreements in granting their partners improved market access; on the other hand, we assess the extent to which domestic sectors are effectively protected. As far as the first objective is concerned, we construct bilateral indicators of protection based on the applied tariffs faced by each exporter. In order to do this, an index of trade policy restrictiveness is computed, using the Mercantilistic Trade Restrictiveness Index as the tariff aggregator. We also analyze the protection granted to each sector by the existing tariff structure. In this respect, we compute effective rates of protection that overcome the well-known theoretical shortcomings of the traditional definition (Output Effective Rate of Protection). The analysis is based on a comparative static applied general equilibrium model (Global Trade Analysis Project) and on the most recent version (release 6) of the related database. Results are obtained with reference to the situation existing in 2001, but the assessment of protection is carried out for the enlarged EU. Overall, it appears that notwithstanding the rhetoric about preferential access, several developing countries are the ones facing the highest hurdles in getting into the EU markets. Both bilateral protection and effective protection rates are broadly consistent with the evolution of the WTO negotiations: the strongest demands from developing countries in terms of market access in the EU have less to do with the overall applied MFN tariffs on industrial products than the reduction of distortions affecting trade in agriculture.Protection, Commercial policy, GTAP model, International trade.
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