Search results for "descent"
showing 10 items of 99 documents
New descent rules for solving the linear semi-infinite programming problem
1994
The algorithm described in this paper approaches the optimal solution of a continuous semi-infinite linear programming problem through a sequence of basic feasible solutions. The descent rules that we present for the improvement step are quite different when one deals with non-degenerate or degenerate extreme points. For the non-degenerate case we use a simplex-type approach, and for the other case a search direction scheme is applied. Some numerical examples illustrating the method are given.
La racionalidad y la sostenibilidad como figuras míticas en el desmontaje del sistema público de servicios sociales
2014
Este artículo constituye un balance de los cambios que se están produciendo en el sistema de servicios sociales de la Comunidad Valenciana: 1) Una contextualización en un eje histórico que concluye con la actual búsqueda de un “consenso retrógrado” para desmontar el sistema público y los movimientos sociales de resistencia; 2) El desplazamiento de la contención social de la crisis desde el sistema de servicios sociales al de seguridad social; 3) Las transformaciones institucionales producidas por la vía presupuestaria; 4) El “efecto bumerang” sobre los Servicios Sociales que produce la implementación de la Ley de “promoción de la autonomía personal y apoyo a las situaciones de dependencia”;…
A Novel Multidimensional Scaling Technique for Mapping Word-Of-Mouth Discussions
2009
The techniques which utilize Multidimensional Scaling (MDS) as a fundamental statistical tool have been well developed since the late 1970’s. In this paper we show how anMDS scheme can be enhanced by incorporating into it a Stochastic Point Location (SPL) strategy (one which optimizes the former’s gradient descent learning phase) and a new Stress function. The enhanced method, referred to as MDS SPL, has been used in conjunction with a combination of the TF-IDF and Cosine Similarities on a very noisy Word-Of-Mouth (WoM) discussion set consisting of postings concerning mobile phones, yielding extremely satisfying results.
Non-cooperative Aerial Base Station Placement via Stochastic Optimization
2019
Autonomous unmanned aerial vehicles (UAVs) with on-board base station equipment can potentially provide connectivity in areas where the terrestrial infrastructure is overloaded, damaged, or absent. Use cases comprise emergency response, wildfire suppression, surveillance, and cellular communications in crowded events to name a few. A central problem to enable this technology is to place such aerial base stations (AirBSs) in locations that approximately optimize the relevant communication metrics. To alleviate the limitations of existing algorithms, which require intensive and reliable communications among AirBSs or between the AirBSs and a central controller, this paper leverages stochastic…
dglars: An R Package to Estimate Sparse Generalized Linear Models
2014
dglars is a publicly available R package that implements the method proposed in Augugliaro, Mineo, and Wit (2013), developed to study the sparse structure of a generalized linear model. This method, called dgLARS, is based on a differential geometrical extension of the least angle regression method proposed in Efron, Hastie, Johnstone, and Tibshirani (2004). The core of the dglars package consists of two algorithms implemented in Fortran 90 to efficiently compute the solution curve: a predictor-corrector algorithm, proposed in Augugliaro et al. (2013), and a cyclic coordinate descent algorithm, proposed in Augugliaro, Mineo, and Wit (2012). The latter algorithm, as shown here, is significan…
Differential geometric least angle regression: a differential geometric approach to sparse generalized linear models
2013
Summary Sparsity is an essential feature of many contemporary data problems. Remote sensing, various forms of automated screening and other high throughput measurement devices collect a large amount of information, typically about few independent statistical subjects or units. In certain cases it is reasonable to assume that the underlying process generating the data is itself sparse, in the sense that only a few of the measured variables are involved in the process. We propose an explicit method of monotonically decreasing sparsity for outcomes that can be modelled by an exponential family. In our approach we generalize the equiangular condition in a generalized linear model. Although the …
Spectral Transmittance of Intraocular Lenses under Natural and Artificial Illumination
2011
Purpose To compare the spectral transmission of different intraocular lenses (IOLs) with either ultraviolet (UV) or blue-light filters, and to analyze the performance of these filters with artificial light sources as well as sunlight. Design Experimental study. Methods The spectral transmission curve of 10 IOLs was measured using a PerkinElmer Lambda 800 UV/VIS spectrometer (Waltham, MA). Different filtering simulations were performed using the D65 standard illuminant as daylight and standard incandescent lamp and fluorescent bulb illuminants. Main Outcomes Measures Spectral transmittance of the IOLs. Results All the IOLs studied provide good UVC (200–280 nm) and UVB (280–315 nm) protection…
Teoría de la educación : revista interuniversitaria
2014
Our aim is to investigate the complex relationship between digital technologies in schools and the decentralization policies, as well as the implications of the resulting pedagogical model. The theoretical framework is grounded in the field of «new public management» which emphasizes the application of indicators, assessments, regulations and self-directed learning as the «management» instruments of organizations. To what extent these policies influence the restructuring of the teaching model? The materials and data of an research project, in which we employ fieldwork survey, observation in schools, interviews, documental analysis and discussion groups, allow us to empirically substantiate …
Pelimusiikin tiedonvälitys osana pelon luomista: analyysi Amnesia : The Dark Descent -tietokonepelin musiikista
2012
Tutkimus koski tietokonepelien musiikille erityisiä piirteitä, joita lähestyttiin hyödyntämällä pelitutkimuksen ja peliäänen tutkimuksen teorioita ja tarkastelutapoja. Pelimusiikkia tarkasteltiin osana pelin käyttöliittymää, jonka välittämä tieto on pelaajan pelissä menestymisen kannalta tärkeää. Tutkimuksen tarkoituksena oli selvittää, mitä pelitiloihin liittyvää tietoa musiikki välittää Amnesia: The Dark Descent -pelissä, sekä kuinka musiikin välittämä tieto vaikuttaa Amnesiassa kohdattavien vihollisten olemukseen kauhun luojina, mikäli pelaaja osaa käyttää musiikkia apuvälineenä pelissä. Tutkimuskohteena oli pelin tiettyihin vihollisiin liittyvä musiikillinen tiedonvälitys, sekä sen suhd…
Multilayer neural networks: an experimental evaluation of on-line training methods
2004
Artificial neural networks (ANN) are inspired by the structure of biological neural networks and their ability to integrate knowledge and learning. In ANN training, the objective is to minimize the error over the training set. The most popular method for training these networks is back propagation, a gradient descent technique. Other non-linear optimization methods such as conjugate directions set or conjugate gradient have also been used for this purpose. Recently, metaheuristics such as simulated annealing, genetic algorithms or tabu search have been also adapted to this context.There are situations in which the necessary training data are being generated in real time and, an extensive tr…