Bilateral stimulus presentation in memory scanning.

24 18–40 yr olds performed a memory-scanning task (S. Sternberg, 1966, 1969) in which probe letters were displayed unilaterally or bilaterally after sets of 2, 4, or 6 letters were memorized. The mean response time (RT) to bilateral presentations was significantly longer than the mean RT to unilateral presentations, but the slope of the set-size function was not affected, suggesting that presenting stimuli bilaterally affected stages other than memory scanning. There were no significant visual-field effects in either the bilateral or unilateral conditions, suggesting that memory scanning is not a lateralized process. There was no evidence that bilateral presentation increased visual-field differences. This is not consistent with D. B. Boles' (1983, 1990) hypothesis that visual-field asymmetry effects are more pronounced with bilateral than with unilateral presentation of stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Strategic Control of Multiple Routes in Imitation of Actions.

The aim of this study was to bring to the surface the strategic use of imitative processes in the context of a 2-route model: (a) direct imitation, used in reproducing new, meaningless actions, and (b) imitation based on stored semantic knowledge of familiar meaningful actions. Three experiments were carried out with healthy participants who reproduced meaningful and meaningless actions within an established time limit. The study investigated 3 factors that could potentially affect the selection of processes used for imitation: (a) the composition of the experimental list (blocked or mixed presentation), (b) the presence-absence of instructions (Experiments 1 and 2), and (c) the relative proportions of the stimuli (Experiment 3). Overall, the results suggest that each of these factors influences the selection of imitative strategies in healthy individuals with temporarily reduced capacities, as happens in the case of brain-damaged patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The accuracy of the computation of optical flow and of the recoveryof motion parameters

The accuracy and the dependence on parameters of a general scheme for the analysis of time-varying image sequences are discussed. The approach is able to produce vector fields from which it is possible to recover 3-D motion parameters such as time-to-collision and angular velocity. The numerical stability of the computed optical flow and the dependence of the recovery of 3-D motion parameters on spatial and temporal filtering is investigated. By considering optical flows computed on subsampled images or along single scanlines, it is also possible to recover 3-D motion parameters from reduced optical flows. An adequate estimate of time-to-collision can be obtained from sequences of images with spatial resolution reduced to 128×128 pixels or from sequences of single scanlines passing near the focus of expansion. The use of Kalman filtering increases the accuracy and the robustness of the estimation of motion parameters. The proposed approach seems to be able to provide not only a theoretical background but also practical tools that are adequate for the analysis of time-varying image sequences     

Continuity properties of solution concepts for cooperative games

Summary A survey is given of known continuity properties of solution concepts for cooperative games. Further continuity properties are derived for the bargaining set, the kernel, the equal division core, the least core, the least tax core, the-value and also for the core of non sidepayment games.

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Zusammenfassung Die Arbeit gibt einen Überblick übebekannte Kontinuitätseigenschaften von Lösungsansätzen für kooperative Spiele. Weiter Kontinuitätseigenschaften werden abgeleitet für die Aushandlungsmenge, den Kernel, den Kern gleicher Aufteilungen, den kleinsten Kern, den kleinsten tax-Kern, den-Wert und den Kern von Spielen ohne Seitenzahlungen.

     

Learning a generic 3D face model from 2D image databases using incremental Structure-from-Motion

Over the last decade 3D face models have been extensively used in many applications such as face recognition, facial animation and facial expression analysis. 3D Morphable Models (MMs) have become a popular tool to build and fit 3D face models to images. Critical to the success of MMs is the ability to build a generic 3D face model. Major limitations in the MMs building process are: (1) collecting 3D data usually involves the use of expensive laser scans and complex capture setups, (2) the number of available 3D databases is limited, and typically there is a lack of expression variability and (3) finding correspondences and registering the 3D model is a labor intensive and error prone process.     

Polynomially Improved Efficiency for Fast Parallel Single-Source Lexicographic Depth-First Search, Breadth-First Search, and Topological-First Search

Although lexicographic (lex) variants of greedy algorithms are often P -complete, NC -algorithms are known for the following lex-search problems: lexicographic depth-first search (lex-dfs) for dags [12], [17], lexicographic breadth-first search (lex-bfs) for digraphs [12], [17], and lexicographic topological-first search (lex-tfs) for dags [12]. For the all-sources version of the problem for dense digraphs, the lex-dfs (lex-bfs, lex-tfs) in [12] is (within a log factor of) work-optimal with respect to the all-sources sequential solution that performs a dfs (bfs, tfs) from every vertex. By contrast, to solve the single-source lexicographic version on inputs of size n , all known NC -algorithms perform work that is at least an n factor away from the work performed by their sequential counterparts. We present parallel algorithms that solve the single-source version of these lex-search problems in O(log  ² n) time using M(n) processors on the EREW PRAM. (M(n) denotes the number of processors required to multiply two n\times n integer matrices in O(log  n) time and has O(n ^2.376 ) as tightest currently known bound.) They all offer a polynomial improvement in work-efficiency over that of their corresponding best previously known and close the gap between the requirements of the best known parallel algorithms for the lex and the nonlex versions of the problems. Key to the efficiency of these algorithms is the novel idea of a lex-splitting tree and lex-conquer subgraphs of a dag G from source s . These structures provide a divide-and-conquer skeleton from which NC -algorithms for several lexicographic search problems emerge, in particular, an algorithm that places in the class NC the lex-dfs for reducible flow graphs—an interesting class of graphs which arise naturally in connection with code optimization and data flow analysis [4], [19]. A notable aspect of these algorithms is that they solve the lex-search problem instance at hand by efficiently transforming solutions of appropriate instances of (nonlex) path problems. This renders them potentially capable of transferring significant algorithmic advances—such as Driscoll et al.'s [14] single-source shortest paths algorithm and Ullman and Yannakakis' [34] transitive closure algorithm—from fundamental (nonlex) path problems to lex-search problems. Received January 9, 1994, and in revised form November 1997. Online publication July 20, 2001.     

Analysis of room temperature magnetic regenerative refrigeration

Results of a room temperature magnetic refrigeration test bed and an analysis using a computational model are presented. A detailed demonstration of the four sequential processes in the transient magnetocaloric regeneration process of a magnetic material is presented. The temperature profile during the transient approach to steady state operation was measured in detail. A 5 °C evolution of the difference of temperature between the hot end and the cold end of the magnetocaloric bed due to regeneration is reported. A model is developed for the heat transfer and fluid mechanics of the four sequential processes in each cycle of thermal wave propagation in the regenerative bed combined with the magnetocaloric effect. The basic equations that can be used in simulation of magnetic refrigeration systems are derived and the design parameters are discussed.     

Neural network approach for multicriteria solid transportation problem

In this paper, we propose neural network approach for multicriteria solid transportation problems(STP). First we suggest a neural network architecture to solve single-objective STP according to augmented Lagrange multiplier method. Due to the massive computing unit-neurons and parallel mechanism of neural network approach can solve the large scale problem efficiently and optimal solution can be got. Then we transform the original multicriteria problem into a single objective problem by global criteria method and adopt the neural network approach to solve it. By this way we can get the satisfactory solution of the original problem. The procedure and efficiency of this approach are shown with numerical simulations.