xDGP: A Dynamic Graph Processing System with Adaptive Partitioning

13 pagesMany real-world systems, such as social networks, rely on mining efficiently large graphs, with hundreds of millions of vertices and edges. This volume of information requires partitioning the graph across multiple nodes in a distributed system. This has a deep effect on performance, as traversing edges cut between partitions incurs a significant performance penalty due to the cost of communication. Thus, several systems in the literature have attempted to improve computational performance by enhancing graph partitioning, but they do not support another characteristic of real-world graphs: graphs are inherently dynamic, their topology evolves continuously, and subsequently the optimum partitioning also changes over time. In this work, we present the first system that dynamically repartitions massive graphs to adapt to structural changes. The system optimises graph partitioning to prevent performance degradation without using data replication. The system adopts an iterative vertex migration algorithm that relies on local information only, making complex coordination unnecessary. We show how the improvement in graph partitioning reduces execution time by over 50%, while adapting the partitioning to a large number of changes to the graph in three real-world scenarios

Analytical and Numerical Methods for Differential Equations and Applications

This research topic shows the large amount of different types of differential equations, thus it contains a selection of papers with recent advances in subjects as different as delay differential equations, nonlinear partial differential equations (PDEs), studied analytically or numerically, or because of their applications, fractional PDEs, and q-differential equations, etc. We would like to thank all the contributors of this issue, and also the referees. They all worked hard to shed some light on these topics for young researchers who would like to investigate some of these areas. Thus, in this research topic, readers can find papers on varying numerical methods and applications

Tratamiento quirúrgico percutáneo del hallux valgus mediante osteotomías múltiples

Objetivo: Se presenta la experiencia del tratamiento del hallux valgus mediante la realización de osteotomía distal del primer metatarsiano y osteotomía de la falange con liberación del abductor por técnicas percutáneas. Material y método: Desde junio de 1996 hasta junio de 1997 han sido intervenidos 64 pacientes, la mayor parte mujeres con hallux valgus de grado moderado con un ángulo intermetatarsiano medio de 14.5° y un ángulo del complejo articular proximal (PASA) de 17,7° de media. Resultados: Los resultados obtenidos desde el punto de vista radiológico pusieron de manifiesto una corrección media de 5° del ángulo intermetatarsal y se obtiene un valor medio del PASA de 8,2°. La consolidación de las osteotomías se consiguió en el 100% de los pies sin retardos de consolidación significativos, salvo en un caso que precisó más de tres meses. Por lo que se refiere a las complicaciones, al no utilizar ningún medio de fijación, el desplazamiento de las osteotomías fue muy frecuente, pero sólo en un 8% de la serie tuvieron repercusión clínica. El acortamiento del primer metarsiano fue la norma alcanzando como media 0,7 cm, lo que se intentó compensar con un descenso de la cabeza del primer metatarsiano; la metatarsalgia por trasferencia en esta serie ocurrió en el 25% de los casos. No se presentaron alteraciones neurológicas, infección ni síndromes flebíticos postquiriírgicos. Conclusión: Parece que la técnica de Reverdin-Isham, por vía percutánea, es un buen método para el tratamiento del hallux valgus. ya que proporciona unos resultados clínicos muy aceptables, sin presentar complicaciones importantes; en el momento actual hay que asociar con mucha más frecuencia la realineación metatarsal a la cirugía del hallux valgus para evitar las metatarsalgias por trasferencia

El cotilo de impactación en las artroplastias de cadera

Entre los diferentes sistemas de fijación de la cúpula acetabular entre las artroplastias no cementadas, la impactación tiene múltiples ventajas. Permite un mejor contacto entre implante y hueso y no necesita destrucción de la superficie ósea receptora. Los nuevos diseños para impactación están fabricados en aleaciones de titanio y poseen una superficie rugosa recubierta a su vez con hidroxiapatita. Algunos modelos como la artroplatia Bihapro poseen aletas estabilizadoras en su reborde externo para evitar la movilización rotatoria inicial. El sistema de impactación está mostrando buenos resultados de la experiencia conocida y aunque los periodos de seguimiento son aún cortos, la integración ósea conseguida es satisfactoria. Se presentan los resultados de 1107 cúpulas Bihapro con una evolución entre uno y siete años, que han seguido un protocolo de seguimiento informatizado. En sólo un caso se presentó movilización del componente que precisó cirugía de revisión.The acetabular fixation by impaction has advantages on other systems of fixing in the cementless arthroplaties of the hip. Permit a better contact between implant and bone and it does not need destruction of the receiving bony surface. The new designs for fixation by impaction are manufactured in titanium alloys and possess a rugged surface cover at the same time with hyrdoxiapatite-coated. Some models as the arthroplasty Bihapro possess fins for primary stability in your external curbing to avoid the initial rotary mobilization. This system of fixation is showing good results in the known experience and though the periods of follow-up are yet short, the obtained bony integration is satisfactory. We presented the results of 117 Bihapro cups implanted with a follow-up from one to seven years, that they have followed a computed protocol. In only a case was presented loosening of the component that specified review surgery

Myocardial thickness by gated PET and SPECT variability and bias

Proceedings of the 40th annual meeting of the Society of Nuclear Medicine, Toronto, Ontario, Canada, June 8-11, 1993Publicad

Multinet : enabler for next generation enterprise wireless services

Wireless communications are currently experiencing a fast migration toward the beyond third-generation (B3G)/fourth generation (4G) era. This represents a generational change in wireless systems: new capabilities related to mobility and new services support is required and new concepts as individual-centric, user-centric or ambient-aware communications are included. One of the main restrictions associated to wireless technology is mobility management, this feature was not considered in the design phase; for this reason, a complete solution is not already found, although different solutions are proposed and are being proposed. In MULTINET project, features as mobility and multihoming are applied to wireless network to provide the necessary network and application functionality enhancements for seamless data communication mobility considering end-user scenario and preferences. The aim of this paper is to show the benefits of these functionalities from the Service Providers and final User point of view

Analytical and Numerical Methods for Differential Equations and Applications

The book is a printed version of the Special issue Analytical and Numerical Methods for Differential Equations and Applications, published in Frontiers in Applied Mathematics and Statistic

Determining realistic electrochemical stability windows of electrolytes for electrical double layer capacitors

Electrical double-layer capacitors are a key building block for energy storage applications, including renewable energies, wherever high power is needed. Most research on electrolytes in this field focuses on improving their electrochemical stability. This improves the energy density as it scales with the square of the maximum operative voltage. However, the decisive criteria to assess the electrochemical stability window of electrolytes are unclear. Consequently, new electrolyte candidates are often presented with unrealistic high stability windows and their performance is difficult to compare. In this Minireview, an overview of electrochemical stability window determination methods is presented. It is argued that constant voltage lifetime tests are needed to confirm the electrochemical stability window determined by any other method. Also, the importance of using realistic working electrodes, reference electrodes, and cycling protocols are highlighted. Finally, an industrial perspective on what is necessary to yield results relevant to applications is given