Growing neural gas as a memory mechanism of a heuristic to solve a community detection problem in networks

Iterative heuristics are commonly used to address combinatorial optimization problems. However, to meet both robustness and efficiency with these methods when their iterations are independent, it is necessary to consider a high number of iterations or to include local search-based strategies in them. Both approaches are very time-consuming and, consequently, not efficient for medium and large-scale instances of combinatorial optimization problems. In particular, the community detection problem in networks is well-known due to the instances with hundreds to thousands of vertices. In the literature, the heuristics to detect communities in networks that use a local search are those that achieve the partitions with the best solution values. Nevertheless, they are not suitable to tackle medium to large scale networks. This paper presents an adaptive heuristic, named GNGClus, that uses the neural network Growing Neural Gas to play the role of memory mechanism. The computational experiment with LFR networks indicates that the proposed strategy significantly outperformed the same solution method with no memory mechanism. In addition, GNGClus was very competitive with a version of the heuristic that employs an elite set of solutions to guide the solution search. (C) 2016 The Authors. Published by Elsevier B.V.Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP) Av. Cesare M. G. Lattes, 1201, Eugênio de Mello, São José dos Campos-SP, CEP: 12247-014, BrasilInstituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP) Av. Cesare M. G. Lattes, 1201, Eugênio de Mello, São José dos Campos-SP, CEP: 12247-014, BrasilWeb of Scienc

Evolución de las actitudes hacia la estadística en estudiantes de psicología

La Estadística se ha incorporado en forma generalizada al currículum de la mayoría de estudios universitarios como fruto del importante papel que desempeña en la formación científica y técnica de profesionales de muy variado perfil. Su estudio ayuda al desarrollo personal, fomentando un razonamiento crítico, basado en la valoración de la evidencia objetiva; así hemos de ser capaces de usar los datos para controlar nuestros juicios e interpretar los de los demás

Visceral leishmaniasis in the State of Maranhão, Brazil: evolution of an epidemic

The authors provide a brief report on the historical evolution of visceral leishmaniasis in the State of Maranhão, Brazil, evaluating possible factors for growth of the disease in the State and control measures by the Brazilian Ministry of Health to integrate health services finto the maintenance of control programs.Os autores fazem um breve relato da evolução histórica da leishmaniose visceral no Estado do Maranhão, Brasil, avaliando as possíveis causas da expansão da referida doença no Estado, assim como as medidas de controle adotadas pelo Ministério da Saúde objetivando a diminuição da incidência da mesma.Universidade Federal do Maranhão Faculdade de Medicina Departamento de PatologiaEscola Paulista de MedicinaUNIFESP, EPMSciEL

Improving the connectivity of community detection-based hierarchical routing protocols in large-scale wsns

The recent growth in the use of wireless sensor networks (WSNs) in many applications leads to the raise of a core infrastructure for communication and data gathering in Cyber-Physical Systems (CPS). The communication strategy in most of the WSNs relies on hierarchical clustering routing protocols due to their ad hoc nature. In the bulk of the existing approaches some special nodes, named Cluster-Heads (CHs), have the task of assembling clusters and intermediate the communication between the cluster members and a central entity in the network, the Sink. Therefore, the overall efficiency of such protocols is highly dependent on the even distribution of CHs in the network. Recently, a community detection-based approach, named RLP, have shown interesting results with respect to the CH distribution and availability that potentially increases the overall WSN efficiency. Despite the better results of RLP regarding the literature, the adopted CH election algorithm may lead to a CH shortage throughout the network operation. In line with that, in this paper, we introduce an improved version of RLP, named HRLP. Our proposal includes a hybrid CH election algorithm which relies on a computationally cheap and distributed probabilistic-based CH recovery procedure to improve the network connectivity. Additionally, we provide a performance analysis of HRLP and its comparison to other protocols by considering a large-scale WSN scenario. The results evince the improvements achieved by the proposed strategy by means of the network connectivity and lifetime metrics. (C) 2016 The Authors. Published by Elsevier B.V.Federal University of São Paulo, Avenida Cesare Mansueto Giulio Lattes, 1201, Parque Tecnológico, 12247014, São José dos Campos-SP-BrazilFederal University of São Paulo, Avenida Cesare Mansueto Giulio Lattes, 1201, Parque Tecnológico, 12247014, São José dos Campos-SP-BrazilWeb of Scienc

Identification of tsunami-induced deposits using numerical modeling and rock magnetism techniques: a study case of the 1755 Lisbon tsunami in Algarve, Portugal

Storm- and tsunami-deposits are generated by similar depositional mechanisms making their discrimination hard to establish using classic sedimentologic methods. Here we propose an original approach to identify tsunami-induced deposits by combining numerical simulation and rock magnetism. To test our method, we investigate the tsunami deposit of the Boca do Rio estuary generated by the 1755 earthquake in Lisbon which is well described in the literature. We first test the 1755 tsunami scenario using a numerical inundation model to provide physical parameters for the tsunami wave. Then we use concentration (MS. SIRM) and grain size (chi(ARM), ARM, B1/2, ARM/SIRM) sensitive magnetic proxies coupled with SEM microscopy to unravel the magnetic mineralogy of the tsunami-induced deposit and its associated depositional mechanisms. In order to study the connection between the tsunami deposit and the different sedimentologic units present in the estuary, magnetic data were processed by multivariate statistical analyses. Our numerical simulation show a large inundation of the estuary with flow depths varying from 0.5 to 6 m and run up of similar to 7 m. Magnetic data show a dominance of paramagnetic minerals (quartz) mixed with lesser amount of ferromagnetic minerals, namely titanomagnetite and titanohematite both of a detrital origin and reworked from the underlying units. Multivariate statistical analyses indicate a better connection between the tsunami-induced deposit and a mixture of Units C and D. All these results point to a scenario where the energy released by the tsunami wave was strong enough to overtop and erode important amount of sand from the littoral dune and mixed it with reworked materials from underlying layers at least 1 m in depth. The method tested here represents an original and promising tool to identify tsunami-induced deposits in similar embayed beach environments

A Hybrid Heuristic for the k-medoids Clustering Problem

Clustering is an important tool for data analysis, since it allows the exploration of datasets with no or very little prior information. Its main goal is to group a set of data based on their similarity (dissimilarity). A well known mathematical formulation for clustering is the k-medoids problem. Current versions of k-medoids rely on heuristics, with good results reported in the literature. However, few methods that analyze the quality of the partitions found by the heuristics have been proposed. in this paper, we propose a hybrid Lagrangian heuristic for the k-medoids. We compare the performance of the proposed Lagrangian heuristic with other heuristics for the k-medoids problem found in literature. Experimental results presented that the proposed Lagrangian heuristic outperformed the other algorithms.UNIFESP, Inst Ciencia & Tecnol, BR-12230280 Sao Jose Dos Campos, SP, BrazilUNIFESP, Inst Ciencia & Tecnol, BR-12230280 Sao Jose Dos Campos, SP, BrazilWeb of Scienc

Serologically diagnosed acute human bocavirus 1 infection in childhood community-acquired pneumonia

AimTo assess the role of human bocavirus 1 (HBoV1) as a causative agent of non-severe community-acquired pneumonia (CAP) in children. MethodsPatients aged 2-59 months with non-severe CAP (respiratory complaints and radiographic pulmonary infiltrate/consolidation) attending a University Hospital in Salvador, Brazil were enrolled in a prospective cohort. From 820 recruited children in a clinical trial ( NCT01200706), nasopharyngeal aspirate (NPA), and acute and convalescent serum samples were obtained from 759 (92.6%) patients. NPAs were tested for 16 respiratory viruses by PCR. Acute HBoV1 infection was confirmed by measuring specific IgM and IgG responses in paired serum samples. ResultsRespiratory viruses were detected in 693 (91.3%; 95%CI: 89.1-93.2) CAP cases by PCR. HBoV1-DNA was detected in 159 (20.9%; 95%CI: 18.2-24.0) cases. Of these 159 PCR positive cases, acute HBoV1 infection was confirmed serologically in 38 cases (23.9%; 95%CI: 17.8-31.0). Overall, acute HBoV1 infection was confirmed in 5.0% (38/759) of non-severe CAP patients. HBoV1 was detected in 151 cases with at least one other virus making 31.7% of all multiple virus (n=477) detections. Among all 759 cases, 216 had one respiratory virus detected, and sole HBoV1 was detected in only 8 (3.7%). Acute HBoV1 infection was serologically diagnosed in 34 (22.5%) HBoV1-DNA-positive cases with another virus, compared to 4 (50.0%) cases with sole virus detection (p=0.09). ConclusionHBoV1 was detected by PCR in one fifth of the children with non-severe CAP and acute HBoV1 infection was serologically confirmed in one quarter of these cases.Peer reviewe

Community detection by consensus genetic-based algorithm for directed networks

Finding communities in networks is a commonly used form of network analysis. There is a myriad of community detection algorithms in the literature to perform this task. In spite of that, the number of community detection algorithms in directed networks is much lower than in undirected networks. However, evaluation measures to estimate the quality of communities in undirected networks nowadays have its adaptation to directed networks as, for example, the well-known modularity measure. This paper introduces a genetic-based consensus clustering to detect communities in directed networks with the directed modularity as the fitness function. Consensus strategies involve combining computational models to improve the quality of solutions generated by a single model. The reason behind the development of a consensus strategy relies on the fact that recent studies indicate that the modularity may fail in detecting expected clusterings. Computational experiments with artificial LFR networks show that the proposed method was very competitive in comparison to existing strategies in the literature. (C) 2016 The Authors. Published by Elsevier B.V.Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP) Av. Cesare M. G. Lattes, 1201, Eugênio de Mello, São José dos Campos-SP, CEP: 12247-014, BrasilInstituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP) Av. Cesare M. G. Lattes, 1201, Eugênio de Mello, São José dos Campos-SP, CEP: 12247-014, BrasilWeb of Scienc

Salt reduction in different bread types: an intervention study in the Northern Portugal

O pão é um dos alimentos mais antigos e consumidos em todo o Mundo, sendo considerado uma boa fonte de diversos nutrientes fundamentais para o desenvolvimento e saúde do organismo. Os dados do Inquérito Alimentar Nacional e de Atividade Física IAN-AF (2015/2016), em Portugal, identificam o pão como sendo considerado um dos principais alimentos a contribuir para a ingestão de sal dos portugueses. A Sociedade Portuguesa de Hipertensão, em colaboração com a Associação dos Industriais de Panificação, Pastelaria e Similares do Norte e o Instituto Nacional de Saúde Doutor Ricardo Jorge, desenvolveram um estudo interventivo com vista a reduzir o teor de sal no pão sem alterar as suas propriedades organoléticas. O objetivo deste estudo foi avaliar o teor de sal em 4 tipos de pão tradicional: carcaça, regueifa, broa e pão da avó, antes e depois da intervenção planeada. Antes da intervenção verificou-se que os valores de teor de sal encontrados, em todos os tipos de pão analisados, estavam abaixo de 1,4 g de sal por 100 g de pão (valor estabelecido pelo Decreto- -Lei n.º 75/2009, de 12 de agosto) e que, após intervenção, foi possível reduzir para valores entre 0,96 e 1,1 g de sal por 100 g de pão, sem alterar as características organoléticas. O estudo realizado demonstrou ser possível a redução do teor de sal no pão, sem alterações adicionais no processo de produção, constituindo uma medida de baixo custo que permite a melhoria da saúde pública, relativamente à prevenção de doenças crónicas associadas ao consumo excessivo de sal.Bread is a key staple in the Portuguese diet and provides many of the nutrients required for normal development and good health. The National Food and Physical Activity Survey IAN-AF (2015/2016), in Portugal, identify bread as one of the main foods contributing to Portuguese salt intake. The Portuguese Society of Hypertension, in collaboration with the Portuguese Bakeries Association from North and the National Institute of Health Dr. Ricardo Jorge, planned an intervention study to reduce the content of salt in the bread, without changing its organoleptic properties. The objective of this study was to evaluate the salt content in four types of traditional bread: “carcaça”, “regueifa”, “broa” e “pão da avó”, before and after the planned intervention. It was found that the values of salt content before the intervention were below the value established in legislation nº 75/2009 of 1.4 g of salt per 100 g of bread and that, after intervention it was possible to reduce the salt content to values between 0.96 and 1.1 g of salt per 100 g of bread, without changing the organoleptic characteristics. The study showed that it is possible to reduce the salt content in bread without additional changes in the production process, and it is a low-cost measure allowing the improvement of public health in relation to the prevention of chronic diseases associated with excessive salt consumptioninfo:eu-repo/semantics/publishedVersio