Collaborative Filtering (CF) Systems have been studied extensively for more than a decade to confront the “information overload” problem. Nearest-neighbor CF is based either on common user or item similarities, to form the user’s neighborhood. The effectiveness of the aforementioned approaches would be augmented, if we could combine them. In this paper, we use biclustering to disclose this dual...

We suggest a simple modification to the kd-tree search algorithm for nearest neighbor search resulting in an improved performance. The Kd-tree data structure seems to work well in finding nearest neighbors in low dimensions but its performance degrades even if the number of dimensions increases to more than three. Since the exact nearest neighbor search problem suffers from the curse of dimensi...

In this paper, modular neural network (MNN) inversion has been applied for the parameters approximation of the gravity anomaly causative target. The trained neural network is used for estimating the amplitude coefficient and depths to the top and bottom of a finite vertical cylinder source. The results of the applied neural network method are compared with the results of the least-squares stand...

In many scientific disciplines structures in highdimensional data have to be found, e.g., in stellar spectra, in genome data, or in face recognition tasks. In this work we present a novel approach to non-linear dimensionality reduction. It is based on fitting K-nearest neighbor regression to the unsupervised regression framework for learning of low-dimensional manifolds. Similar to related appr...

Nearest neighbor searching is an important geometric subproblem in vector quantization. Existing studies have shown that the difficulty of solving this problem efficiently grows rapidly with dimension. Indeed, existing approaches on unstructured codebooks in dimension 16 are little better than brute-force search. We show that if one is willing to relax the requirement of finding the true neares...

Mobile query processing is, actually, a very active research field. Range and nearest neighbor queries are common types of queries in spatial databases and location based services (LBS). In this paper, we focus on finding nearest neighbors of a query point within a certain distance range. An example of query, frequently met in LBS, is “Find all the nearest gas stations within 2 miles neighborho...

We suggest a simple modification to the Kd-tree search algorithm for nearest neighbor search resulting in an improved performance. The Kd-tree data structure seems to work well in finding nearest neighbors in low dimensions but its performance degrades even if the number of dimensions increases to more than two. Since the exact nearest neighbor search problem suffers from the curse of dimension...

To explain the experimental spectra for angle resolved photoemission we consider a modified t − J model. The modified model includes next nearest (t′) and next next nearest (t′′) hopping as well as Hubbard model corrections to the spectral weights.A Dyson equation which relates the single hole Green’s functions for a given pseudospin and given spin is derived and is compared to experimental res...

The use of Saccharomyces cerevisiae mnn mutants has facilitated the study of the epitopes recognized by antisera against several antigenic factors of the genus Candida (Candida Check; Iatron Laboratories, Tokyo, Japan). We have taken advantage of the very well characterized structure of the mannans of the different mnn mutants to compare their reactivities with the factor antisera used in the i...