Parallel performance prediction for multigrid codes on distributed memory architectures

We propose a model for describing the parallel performance of multigrid software on distributed memory architectures. The goal of the model is to allow reliable predictions to be made as to the execution time of a given code on a large number of processors, of a given parallel system, by only benchmarking the code on small numbers of processors. This has potential applications for the scheduling of jobs in a Grid computing environment where reliable predictions as to execution times on different systems will be valuable. The model is tested for two different multigrid codes running on two different parallel architectures and the results obtained are discussed

Parallel performance prediction for numerical codes in a multi-cluster environment

We propose a model for describing and predicting the performance of parallel numerical software on distributed memory architectures within a multi-cluster environment. The goal of the model is to allow reliable predictions to be made as to the execution time of a given code on a large number of processors of a given parallel system, and on a combination of systems, by only benchmarking the code on small numbers of processors. Thishas potential applications for the scheduling of jobs in a Grid computing environment where informed decisions about which resources to use in order to maximize the performance and/or minimize the cost of a job will be valuable. The methodology is built and tested for a particular class of numerical code, based upon the multilevel solution of discretized partial differential equations, and despite its simplicity it is demonstrated to be extremely accurate and robust with respect to both the processor and communications architectures considered. Furthermore,results are also presented which demonstrate that excellent predictions may also be obtained for numerical algorithms that are more general than the pure multigrid solver used to motivate the methodology. These are based upon the use of a practical parallel engineering code that is briefly described. The potential significance of this work is illustrated via two scenarios which consider a Grid user who wishes to use the available resources either (i) to obtain a particular result as quickly as possible, or (ii) to obtain results to different levels of accuracy. Index Terms—Parallel Distributed Algorithms; Grid Computing; Cluster Computing; Performance Evaluation and Prediction; Meta-Scheduling

(Dis)orientamento politico e precariet\ue0 lavorativa come fattori di rischio di esclusione sociale: i giovani italiani tra crisi e prospettive. Uno studio di caso

The author investigates the \u201cyouth universe\u201d in Italy; specifically, the hard relationship between it and politics and institutions, characterized by a lack of trust and credibility. The question of the absence of work makes the Italian case unique and exemplary: young people are precarious, inadequately paid. Unemployment, the late age to the first job and atypical contracts impoverish young people of the potential wealth they could carry around: innovation, change, planning, growth and future; all that exclude them from the country\u2019s decision-making processes. Thus, housing autonomy and economic independence are postponed, hence the transition to adulthood. Deprived of the fixed points that guided previous generations, today\u2019s young people do not recognize themselves into any ideology, do not feel represented by any political force. An investigation carried out close to the elections of March 4, 2018 confirmed what has been exposed so far and noted that the consequent discontent found a possibility of expression and change in the neophyte Movimento 5 Stelle. Therefore, it is appropriate to ask ourselves what are the motivations and conditions that have led young people, disappointed and disillusioned, to move away from \u201ctraditional politics\u201d. It is urgent to promote a cultural revolution to give young Italians the role of protagonists of present, backed by tradition but making space to the new and welcoming the future. Which role does the family play as the primary agency for political education? What proposal can make pedagogy of family educational relationships

Dal bambino libero all’uomo autonomo: educare alla scelta attraverso il metodo Montessori

Freedom, autonomy and responsibility are the ends of every educational process, especially in the modern society: globalized, rapid, in transformation; society in which each one of us is called to make numerous choices. Therefore, it is urgent to educate to choose and educate to the choice, so that young people can emancipate themselves from possible conditionings. To this end, the Montessori method represents a privileged way: child is free to choose his own activity and learns “to do by himself” soon; the teacher prepares the environment and the materials that allow the student to satisfy the educational needs of each period of inner development. Then, Montessori gives importance to adolescence because it is during this period that grows the social man. Consequently, it is important to reform the secondary school in order to acquire the autonomy that each student will apply to the subsequent school grades and to all areas of life

Piccole “femmine” crescono. La donna nella pop-modernità

A partire dai pesanti condizionamenti culturali che gravavano sull’educazione dei bambini e delle bambine nella società patriarcale, fortemente ancorata alle differenze di genere, l’autore si chiede se e in quale misura persistano, oggi, tali stereotipi. A tal fine, viene analizzata, e, talvolta, smascherata, la logica subliminale sottesa alla pubblicità, ai giocattoli, ai cartoni animati: dai classici ai più recenti, e, finanche, ai libri di testo scolastici. In molti casi, emerge un vero e proprio processo di induzione e allenamento dei più piccoli ad assumere, nel futuro, i tradizionali ruoli stereotipati. Seppure non trascurabili sono i danni causati ai bambini, castrati soprattutto nell’emotività, il bilancio risulta nettamente a sfavore delle bambine. Queste, infatti, vengono avviate a una precoce iperfemminilizzazione e persuase che la seduttività sia l’unico potere di cui dispongano. In chiave pedagogica, questo fenomeno viene colto anche come conseguenza dell’assenza o carenza della figura paterna, in quanto luogo di promozione della differenza. Pertanto, l’apertura progettuale si dà in una inedita paternità tenera. La riflessione si conclude nel segno della speranza, testimoniata da alcune principesse pop-moderne che, emancipandosi, si sono salvate da sole

Drug Release from Viscoelastic Swelling Polymeric Platforms

We consider a polymeric spherical platform containing a solid dispersed drug that is in contact with a solvent fluid. While swelling, a non-Fickian sorption of the solvent molecules occurs induced by the effect of the viscoelastic properties of the polymer. The solid drug in contact with the solvent fluid dissolves and a Fickian release of dissolved drug takes place. The fluid entrance, the drug dissolution, and the drug release to an external environment are described by a system of PDEs complemented with an equation for the swelling front, initial, and boundary conditions. The model includes the two major factors that govern a swelling process of a polymeric platform within a release medium: the cross-link density and the concentration of the external medium. Energy estimates for the mass of solvent fluid and of undissolved and dissolved drug in the polymeric platform are established. Numerical simulations that illustrate the theoretical results are also included