Disposition of sex offender cases in the Superior Courts of Norfolk and Plymouth Counties

Thesis (M.S.)--Boston Universit

A Graphical Model Formulation of Collaborative Filtering Neighbourhood Methods with Fast Maximum Entropy Training

Item neighbourhood methods for collaborative filtering learn a weighted graph over the set of items, where each item is connected to those it is most similar to. The prediction of a user's rating on an item is then given by that rating of neighbouring items, weighted by their similarity. This paper presents a new neighbourhood approach which we call item fields, whereby an undirected graphical model is formed over the item graph. The resulting prediction rule is a simple generalization of the classical approaches, which takes into account non-local information in the graph, allowing its best results to be obtained when using drastically fewer edges than other neighbourhood approaches. A fast approximate maximum entropy training method based on the Bethe approximation is presented, which uses a simple gradient ascent procedure. When using precomputed sufficient statistics on the Movielens datasets, our method is faster than maximum likelihood approaches by two orders of magnitude.Comment: ICML201

Signal propagation on κ\kappa-Minkowski spacetime and non-local two-point functions

We study the propagation of quantum fields on $\kappa$-Minkowsi spacetime. Starting from the non-commutative partition function for a free field written in momentum space we derive the Feynman propagator and analyze the non-trivial singularity structure determined by the group manifold geometry of momentum space. The additional contributions due to such singularity structure result in a deformed field propagation which can be alternatively described in terms of an ordinary field propagation determined by a source with a blurred spacetime profile. We show that the $\kappa$-deformed Feynman propagator can be written in terms of vacuum expectation values of a commutative non-local quantum field. For sub-Planckian modes the $\kappa$-deformed propagator corresponds to the vacuum expectation value of the time-ordered product of non-local field operators while for trans-Plankian modes this is replaced by the Hadamard two-point function, the vacuum expectation value of the anti-commutator of non-local field operators.Comment: 29 pages, 10 figures; v2: typos corrected, references adde

Sustainability of Local Agri-food Products in the Border Area of Northern Portugal and Castilla-Léon

Even in relatively peripheral areas, such as the Portuguese-Spanish border regions, agriculture and food systems have changed greatly in the last decades. Traditional agricultural systems have been declining and some products are no longer appreciated, or even tend to become quantitatively insignificant. Not only are producers ageing but their knowledge and know-how along with the local genetic heritage and biodiversity associated with farming are at risk of disappearing. Local products and markets have been progressively integrated into the larger framework of the global food market. Distributors, restaurant owners and consumers in general rely more and more on exogenous food products, despite the undeniable quality of the existing products and the emerging new urban demand for these products at a larger scale. Recent studies show that there is still room for small-scale production and localized food systems, although a considerable effort needs to be made if they are to be strengthened or re-established. This paper presents a comparative study of both the potential and limitations of traditional local products in the border area of Northern Portugal and the Spanish Province of Salamanca, in Castilla-Léon. It analyzes the types of products, production processes, qualification strategies, as well as the markets and commercialization approaches. The study is based on official published documents and interviews with local producers. Results show that the Portuguese regions are better positioned in terms of number of producers of traditional products, especially the organic products. On the whole, the major difficulties seem to lie in adequately qualifying, promoting and commercializing the products. Besides, co-operation among local agri-food entrepreneurs (in each zone and across the border) is quite feeble and does pose a challenge for the future. In general, localized systems tend to be quite weak, due to the decrease in population and the poor co-ordination among actors and the organization of local supply chains.Local agri-food products, peripheral areas, Portugal, Spain., Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Food Consumption/Nutrition/Food Safety, Labor and Human Capital,

Localization of JPEG double compression through multi-domain convolutional neural networks

When an attacker wants to falsify an image, in most of cases she/he will perform a JPEG recompression. Different techniques have been developed based on diverse theoretical assumptions but very effective solutions have not been developed yet. Recently, machine learning based approaches have been started to appear in the field of image forensics to solve diverse tasks such as acquisition source identification and forgery detection. In this last case, the aim ahead would be to get a trained neural network able, given a to-be-checked image, to reliably localize the forged areas. With this in mind, our paper proposes a step forward in this direction by analyzing how a single or double JPEG compression can be revealed and localized using convolutional neural networks (CNNs). Different kinds of input to the CNN have been taken into consideration, and various experiments have been carried out trying also to evidence potential issues to be further investigated.Comment: Accepted to CVPRW 2017, Workshop on Media Forensic