Modeling the evolution of item rating networks using time-domain preferential attachment

The understanding of the structure and dynamics of the intricate network of connections among people that consumes products through Internet appears as an extremely useful asset in order to study emergent properties related to social behavior. This knowledge could be useful, for example, to improve the performance of personal recommendation algorithms. In this contribution, we analyzed five-year records of movie-rating transactions provided by Netflix, a movie rental platform where users rate movies from an online catalog. This dataset can be studied as a bipartite user-item network whose structure evolves in time. Even though several topological properties from subsets of this bipartite network have been reported with a model that combines random and preferential attachment mechanisms [Beguerisse Díaz et al., 2010], there are still many aspects worth to be explored, as they are connected to relevant phenomena underlying the evolution of the network. In this work, we test the hypothesis that bursty human behavior is essential in order to describe how a bipartite user-item network evolves in time. To that end, we propose a novel model that combines, for user nodes, a network growth prescription based on a preferential attachment mechanism acting not only in the topological domain (i.e. based on node degrees) but also in time domain. In the case of items, the model mixes degree preferential attachment and random selection. With these ingredients, the model is not only able to reproduce the asymptotic degree distribution, but also shows an excellent agreement with the Netflix data in several time-dependent topological properties.

Celebre centuria que consagro la ilustre y real villa de Alcoy a honor y culto del soberano Sacramêto del Altar ... en el año 1668

Pie de imp. en colofón

Design of a twin capacitive load and its application to the outdoor rating of photovoltaic modules

This paper describes the design of an original twin capacitive load that is able of tracing simultaneously the I?V characteristics of two photovoltaic modules. Besides, an example of the application of this dual system to the outdoor rating of photovoltaic modules is presented, whose results have shown a good degree of repeatability.

Á la estatua erigida por la ciudad de Valencia en honor de su augusto soberano Fernando VII : y en memoria del dia 23 de mayo del año 1808 : odas

Hay un ejemplar encuadernado con: Excelencias y admirables frutos del agua bendita sacados del capítulo 31, de la vida de la esclarezida Virgen Santa Teresa de Jesus ... del angelico ... Santo Thomas ; del glorioso P. San Vicente Ferrer ... (XVIII/1682).

Verdadera relacion y curioso romance en que se declara el escandaloso, inaudito, y grave desacato que ha executado en ... Madrid una infeliz ... ultrajando insolente el Soberano Cuerpo de Christo ... y el riguroso exemplar castigo ...

El pie de imp. consta en colofón

Afectos de un pecador arrepentido, : compareciendo en la presencia de Christo Señor nuestro, puesto en el soberano trono de la cruz, pidiendo à su divina Magestad el caudal de sus misericordias

Contiene: Tiernas humildes pretensiones, que en amorosos confiados ruegos se dirigen a Maria Santisima solicitandola medianera para la presentacion de los antecedentes Afectos

Carta que escrive el Dr. Joseph Berní, y Català, ... al ... Sr. D. Gregorio Mayans, y Siscar ... implorando Sus doctas Advertencias para la mayor defensa del Soberano Rey Godo Witiza

Sign. : A4

Verdadera relacion, y curioso romance, en que se declara el escandaloso, inaudito, y grave desacato que ha executado en ... Madrid una infeliz, viciosa y desordenada muger, ultrajando insolente el soberano Cuerpo de Christo nuestro Redemptor, en la Sacratissima Hostia Consagrada : y el riguroso exemplar castigo ... : sucedio el dia 25 de marzo de este año 1753

Pie de imp. consta en col

Noticia de una gran tempestad, que se origino en Valencia el dia del Corpus nueve de junio de 1746 ... : al tiempo que la procession iva en su mayor luzimiento, y estando la Custodia del Soberano Sol de Justicia en la Plaza del Mercado ... : [primera (-segunda) parte]

Sign.: []2

Celebre centuria que consagro la ilustre y real villa de Alcoy a honor, y culto del Soberano Sacramento del Altar (que sea por siempre alabado) en el ano 1668

Anadense las historias de S. George y los sucesos de los terremotos

SOPHIA CPV module round robin: power rating at CSOC

Within the European funded project SOPHIA, a Round Robin measurement on CPV module has been initiated. Seven different test laboratories located in Europe between 48°N and 37°N perform measurements of four SOITEC CPV modules. The modules are electrically characterized with different measurement equipment under various climatic conditions. One pyrheliometer and one spectral sensor based on component cells are shipped together with the modules. This ensures that the irradiance and spectrum, two factors with high impact on CPV module performance, are measured with the identical equipment at each site. The round robin activity is performed in closeco-operation with the IEC TC82 WG7 power rating team in order to support the work on the CPV module power rating draft standard 62670-3. The resultingrated module power outputs at CSOC (Concentrator Standard Operating Conditions) are compared amongst the power rating methods and amongst the test labs. In this manner, a deviation in rated power output between different test labs and power rating methods is determined.

Oracion panegirica en gloria del soberano misterio de la Purissima Concepcion, que se predico en su dia en la Santa y Metropolitana Iglesia de Valencia [Texto impreso]

Sign.: [ ]4, A-B4