Comparing MapReduce and pipeline implementations for counting triangles

A common method to define a parallel solution for a computational problem consists in finding a way to use the Divide and Conquer paradigm in order to have processors acting on its own data and scheduled in a parallel fashion. MapReduce is a programming model that follows this paradigm, and allows for the definition of efficient solutions by both decomposing a problem into steps on subsets of the input data and combining the results of each step to produce final results. Albeit used for the implementation of a wide variety of computational problems, MapReduce performance can be negatively affected whenever the replication factor grows or the size of the input is larger than the resources available at each processor. In this paper we show an alternative approach to implement the Divide and Conquer paradigm, named dynamic pipeline. The main features of dynamic pipelines are illustrated on a parallel implementation of the well-known problem of counting triangles in a graph. This problem is especially interesting either when the input graph does not fit in memory or is dynamically generated. To evaluate the properties of pipeline, a dynamic pipeline of processes and an ad-hoc version of MapReduce are implemented in the language Go, exploiting its ability to deal with channels and spawned processes. An empirical evaluation is conducted on graphs of different topologies, sizes, and densities. Observed results suggest that dynamic pipelines allows for an efficient implementation of the problem of counting triangles in a graph, particularly, in dense and large graphs, drastically reducing the execution time with respect to the MapReduce implementation.Peer ReviewedPostprint (published version

THE BEQUEST MOTIVE AND SINGLE PEOPLE’S DEMAND FOR LIFE ANNUITIES

The main objective of this paper is to go deeper into the “annuity puzzle” by introducing the altruistic and strategic bequest motive and determining whether this really is a relevant factor affecting the theoretical decision to purchase life annuities. With this end in view we develop an optimization model based on that first put forward by Lejárraga et al. [2002], then add to it elements from other models such as Friedman and Warshawsky’s [1990] and Jousten’s [1998 & 2001] which include the bequest motive. We also analyse welfare by calculating the equivalent wealth in different contexts: the possibility of having access to an actuarially fair life annuity or programmed withdrawal market, the incorporation of so-called market imperfections, and the inclusion of the hypothesis that the individuals already have part of their wealth in pre-existing life annuities.Capitalization, Pension Funds, Phased Withdrawal, Retirement, Utility.

Dynamic energy budget approach to evaluate antibiotic effects on biofilms

Quantifying the action of antibiotics on biofilms is essential to devise therapies against chronic infections. Biofilms are bacterial communities attached to moist surfaces, sheltered from external aggressions by a polymeric matrix. Coupling a dynamic energy budget based description of cell metabolism to surrounding concentration fields, we are able to approximate survival curves measured for different antibiotics. We reproduce numerically stratified distributions of cell types within the biofilm and introduce ways to incorporate different resistance mechanisms. Qualitative predictions follow that are in agreement with experimental observations, such as higher survival rates of cells close to the substratum when employing antibiotics targeting active cells or enhanced polymer production when antibiotics are administered. The current computational model enables validation and hypothesis testing when developing therapies.Comment: to appear in Communications in Nonlinear Science and Numerical Simulatio

Farmers' Demand for Information about Agribusiness

This study is focused on the habits of the Brazilian farmers that access the Internet for searching information to their economical activities. The main goal is to understand how come those agents of the agribusiness use the formal and informal (personal contact) means of communication, as well as the functions that each of those means accomplish to this public. In other words, it intends to identify the channels of communication of major importance to farmers (used more often, considered the ones of more credibility and preferred among them). That is possible by means of a questionnaire sent exclusively by e-mail, answered by Brazilian farmers. The motivation of the study is to contribute to make the communication more efficient to those who work on farms. That can produce benefits to the communication companies and to the public. The results show that the Internet is the mean of communication more often used and preferred on the process of searching information about the agribusiness among Brazilian farmers. The personal contact, not considered in the valuation about preference, appears in second position in the ranking for intensity of use. On the other hand, the radio, regional press newspapers and newsletters of class entities were the less consulted and the last ones in the ranking of preference.Agribusiness, Teaching/Communication/Extension/Profession,

DEMAND FOR LIFE ANNUITIES FROM MARRIED COUPLES WITH A BEQUEST MOTIVE

This paper will try to explain the “annuities puzzle” in greater depth by introducing the bequest motive, both strategic and altruistic. It will try to determine whether this motive really is a relevant feature influencing the demand for lifetime annuities by married couples. With this aim in mind, we develop an optimization model of the utility provided by purchasing a lifetime annuity with contingent survivor benefit or a joint survivor life annuity. This will enable us to calculate equivalent wealth in various contexts: the possibility of access to actuarially fair annuity markets, the inclusion of so-called market imperfections, and the assumption that couples already have part of their wealth in pre-existing lifetime annuities. Results are presented for a model specification calibrated to Spain.Capitalization, Pension Funds, Retirement, Utility.

A Learning perspective on strategy : empirical evidence from Japanese firms

Thesis (Ph. D. in Economics)--University of Tsukuba, (A), no. 2736, 2002.1.31Includes bibliographical reference

Achegamento á problemática da equivalencia ou non equivalencia entre adxectivos e frases preposicionais.

Sin resumenveña buscar respostas máis alá da semántica e axu darnos doutros feudos lingáisticos, tales coma a pragmática ou a estilística, por exemplo. O que In this article we draw attention to the queda patente é que cómpre seguir un dos duality presented by selected examples, ños que, segundo autores como Apresjan, caracte which apparently convey the same informa rizan hoxe a lingiiistica, o de abordar unidades tion: whether it be in the choice of adjective superiores á palabra. Con rodo, estamos a medio or the choice of corresponding prepositional camiño entre a micro e a macrosemántica, xa que phrase. In order to discover whether we have esta última se centra sobre todo en oracións e tex a case of equivalence, we go through a pro tos e nós ocupámonos de frases. cess of examining the different view points Comezaremos facendo un percorrido poíos dis adopted by the scholars when faced wirh tintos puntos de vista que adoptaron os estudiosos identical or similar linguistic realities. In a respecto do asunto que abordamos e a continua second phase of the study, we give the results ción efectuarémo-la análise dun grupo de exem of the research into these types of examples, píos seguida das correspondentes conclusións. examples from a body of etbnological texts, taken from spoken Calician. The aim behind this is to approach the problematic from a purely practical perspective. We POSICIONAMENTO DOS ESTUDIOSOS attempt to form groups from pairs with similar characteristics. We then analyze the Buscamos primeiro respostas nos xenerativistas possible nuances differentiating the two co fin de indagar se son quen de explicar esta options. Throughout this srudy, we reveal correspondencia entre adxectivos e frases preposi how the various linguistic factors: semantic, cionais a través dalgún tipo de «transformación». A pragmatic and stylistic, intervene in the obra máis antiga que consultamos é a de N. Ruwet, choice of adjective or pbrase

Dynamic Pipeline: an adaptive solution for big data

The Dynamic Pipelineis a concurrent programming pattern amenable to be parallelized. Furthermore, the number of processing units used in the parallelization is adjusted to the size of the problem, and each processing unit uses a reduced memory footprint. Contrary to other approaches, the Dynamic Pipeline can be seen as ageneralization of the (parallel) Divide and Conquer schema, where systems can be reconfigured depending on the particular instance of the problem to be solved. We claim that the Dynamic Pipelines is useful to deal with Big Data related problems. In particular, we have designed and implemented algorithms for computing graphs parameters as number of triangles, connected components, and maximal cliques, among others. Currently, we are focused on designing and implementing an efficient algorithm to evaluate conjunctive query.Peer ReviewedPostprint (author's final draft

La Educación Artística en el aula de Educación Infantil: una propuesta didáctica inspirada en la Teoría de las Inteligencias múltiples a través de la figura de Pablo Picasso

El presente Trabajo Fin de Grado expone un recorrido por la educación plástica en el segundo ciclo de Educación Infantil, tanto en el currículo, a lo largo de los años como actualmente, y en el aula ideal de infantil para un desarrollo de educación artística, contando con una metodología basada en la teoría de las inteligencias múltiples de Gardner. La segunda parte del documento consiste en una propuesta didáctica, afianzando cada inteligencia, y teniendo como hilo conductor a Pablo Ruiz Picasso, conociendo sus obras, biografía, utilizando técnicas y recursos artísticos y destinada a niños de tres años de edad.Grado en Educación Infanti

Aproximación ás causais e consecutivas en galego medieval

Dirección Xeral de Política Lingüística da Consellería de Educación da Xunta de Galici