Speed limits: Orientation and semantic context interactions constrain natural scene discrimination dynamics.

The visual system rapidly extracts information about objects from the cluttered natural environment. In 5 experiments, the authors quantified the influence of orientation and semantics on the classification speed of objects in natural scenes, particularly with regard to object-context interactions. Natural scene photographs were presented in an object-discrimination task and pattern masked with various scene-to-mask stimulus-onset asynchronies (SOAs). Full psychometric functions and reaction times (RTs) were measured. The authors found that (a) rotating the full scenes increased threshold SOA at intermediate rotation angles but not for inversion; (b) rotating object or context degraded classification performance in a similar manner; (c) semantically congruent contexts had negligible facilitatory effects on object classification compared with meaningless baseline contexts with a matching contrast structure, but incongruent contexts severely degraded performance; (d) any object-context incongruence (orientation or semantic) increased RTs at longer SOAs, indicating dependent processing of object and context; and (e) facilitatory effects of context emerged only when the context shortly preceded the object. The authors conclude that the effects of natural scene context on object classification are primarily inhibitory and discuss possible reasons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantics as a Foundation for Psychology: A Case Study of Wason's Selection Task

We review the various explanations that have been offered toaccount for subjects' behaviour in Wason's famous selection task. Weargue that one element that is lacking is a good understanding ofsubjects' semantics for the key expressions involved, and anunderstanding of how this semantics is affected by the demands the taskputs upon the subject's cognitive system. We make novel proposals inthese terms for explaining the major content effects of deonticmaterials. Throughout we illustrate with excerpts from tutorialdialogues which motivate the kinds of analysis proposed. Our long termgoal is an integration of the various insights about conditionalreasoning on offer from different cognitive science methodologies. Thepurpose of this paper is to try to draw the attention of logicians andsemanticists to this area, since we believe that empirical investigationof the cognitive processes involved could benefit from semanticanalyses.     

Event fairness and non-interleaving concurrency

Event fairness suitable for non-interleaving concurrency is proposed. Fairness is viewed with respect to concurrency, rather than non-determinism, in the sense that no concurrent component of the system should be delayed indefinitely. Shields' asynchronous transition systems and Mazurkiewicz's traces have been used; the model gives rise to a partial order. A class of generalised notions of (weak, strong and unconditional) event fairness relative to progress requirements is derived. The weakest fairness notion in this class is shown to coincide with maximality with respect to the partial order over traces.     

Computing the algebraic relations of C-finite sequences and multisequences

We present an algorithm for computing generators for the ideal of algebraic relations among sequences which are given by homogeneous linear recurrence equations with constant coefficients. Knowing these generators makes it possible to use Gröbner basis methods for carrying out certain basic operations in the ring of such sequences effectively. In particular, one can answer the question whether a given sequence can be represented in terms of other given sequences.     

THE TRUE DIMENSION OF CERTAIN ALTERNANT CODES

By applying a result from geometric Goppa codes, due to H.Schtenoth, the true dimension of certain alternant codes is calculated. The results lead in many cases to an improvement of the usual lower bound for the dimension.     

产品语境分析与产品设计定位

一个新的产品能否成功,除了取决于产品本身的品质外,还要看该产品的设计定位是否准确,通过对产品周围环境的语境进行分析,可以使设计者能更好地明确设计目的和任务,并以此来对产品进行准确定位。因此,正确地分析产品语境,是设计活动中的一个重要的环节。目前,设计管理活动也从"设计生产后促销"转变为"设计前决策",因此产品语境分析是一种有效的辅助设计定位的手段。     

A model based atomic resolution tomographic algorithm

Tomography with high angular annular dark field scanning transmission electron microscopy at atomic resolution can be greatly improved if one is able to take advantage of prior knowledge. In this paper we present a reconstruction technique that explicitly takes into account the microscope parameters and the atomic nature of the projected object. This results in a more accurate estimate of the atomic positions and in a good resistance to noise. The reconstruction is a maximum likelihood estimator of the object. Moreover, the limits to the precision have been explored, allowing for a prediction of the amount of expected noise in the reconstruction for a certain experimental setup. We believe that the proposed reconstruction technique can be generalized to other tomographic experiments.     

Function-field codes

Function-field codes provide a general perspective on the construction of algebraic-geometry codes. We briefly review the theory of function-field codes and establish some new results in this theory, including a propagation rule. We show how to derive linear codes from function-field codes, thus generalizing a construction of linear codes due to Xing, Niederreiter, and Lam. The research of the second and third author was partially supported by the DSTA research grant R-394-000-025-422 with Temasek Laboratories in Singapore.