Several studies have suggested recently that a more dynamic conflict resolution mechanism in the ACT–R cognitive architecture (Anderson & Lebiere, 1998) could improve the decision–making behaviour of cognitive models. This part of ACT–R theory is revisited and a new solution is proposed. The new algorithm (OPTIMIST) has been implemented as an overlay to the ACT–R architecture, and can be used a...

In this paper, we propose a new method for indexing large amounts of point and spatial data in highdimensional space. An analysis shows that index structures such as the R*-tree are not adequate for indexing high-dimensional data sets. The major problem of R-tree-based index structures is the overlap of the bounding boxes in the directory, which increases with growing dimension. To avoid this p...

We propose a spatio-temporal access method for objects that move through a set of fixed and disjoint regions. The proposal is based on an R-tree, on a temporal access method and on a hashing scheme. With our method it is possible to respond to queries of the timeslice and interval types as well as queries about the trajectory that an object has followed. It is also possible to process spatio-te...

A classical result from graph theory is that every graph with chromatic number χ > t contains a subgraph with all degrees at least t, and therefore contains a copy of every t-edge tree. Bohman, Frieze, and Mubayi recently posed this problem for r-uniform hypergraphs. An r-tree is an runiform hypergraph with no pair of edges intersecting in more than one vertex, and no sequence of distinct verti...

Many spatio-temporal access methods, such as the HR-tree, the 3DR-tree, and the MV3R-tree, have been proposed for timestamp and interval queries. However, these access methods have the following problems: the poor performance of the 3DR-tree for timestamp queries, the huge size and the poor performance of the HR-tree for interval queries, and the large size and the high update cost of the MV3R-...

In this paper, we present a clustering-based color indexing scheme for effective amd efficient image retrieval, which is essentially an exploration on the application of clustering technique to image retrieval. In our approach, the color features are clustered automatically using a color clustering algorithm twice (called two-level clustering processing) and two color feature summarizations are...

We prove an acylindrical accessibility theorem for finitely generated groups acting on R-trees. Namely, we show that if G is a freely indecomposable non-cyclic k-generated group acting minimally and D-acylindrically on an R-tree X then there is a finite subtree Tε ⊆ X of measure at most 2D(k − 1) + ε such that GTε = X. This generalizes theorems of Z. Sela and T. Delzant about actions on simplic...

Article history: Received 12 March 2015 Accepted 28 June 2015 Available online 22 July 2015

In this paper we address the problem of indexing spatial data, in particular two dimensional rectangles. We propose an approach which uses two B +-trees, each of them indexing the projected sides of the given rectangles. The approach, which we name 2dMAP21, can also be easily parallelized. We focus on queries of the type \\nd all rectangles included within another (reference) rectangle". We com...

Deep convolutional neural networks (CNNs) have had a major impact in most areas of image understanding, including object category detection. In object detection, methods such as R-CNN have obtained excellent results by integrating CNNs with region proposal generation algorithms such as selective search. In this paper, we investigate the role of proposal generation in CNN-based detectors in orde...