Heading south with a north-up map: A choice processing analysis of map alignment effects

This study employed an information accumulation model of choice reaction times to investigate alignment effects in mental representations of maps. University students studied a map from a single orientation (with north at the top). In a subsequent two-choice reaction time task, the students’ spatial knowledge of the map was assessed employing spatial left/right judgments, which were made from imagined perspectives that were either north-aligned or south-aligned. Data showed a standard alignment effect, favoring north- over south-aligned trials. To examine the locus of this effect, data were fit using the Linear Ballistic Accumulator (LBA) model of speeded decisions (Brown & Heathcote, 2008). Of interest were three model parameters: drift rate, the speed at which evidence accumulates toward a response; response threshold, the amount of evidence demanded from the decision maker before selecting a response; and non-decision time, the time consumed by pre- and postdecisional processes. The best-fitting model suggested that non-decision time accounted for the alignment effect. The difference in non-decision time between north and south-aligned judgments suggests a mental alignment stage on south-aligned trials, accounting for the longer reaction times for judgements misaligned with the presented north orientation of the map.     

Spatial memory exclusivity: Examining performance of multiple object-location memories

Research on location memory suggests that integration of separate sources of information does not occur when recalling the position of a common target object. In a relatively simple task, previous research shows no observable benefit from holding two spatial memories compared to one. It has been suggested that exclusively utilizing only one of two memories may account for this finding. The current research tests the robustness of this idea as well as an alternative in the form of an averaging approach to combining spatial information. The results suggest that exclusivity may not be the best account for performance of multiple object-location memories. Rather, memories may well combine in a manner similar to averaging, where information is available for each memory but combined in a nonbeneficial way.     

Investigating behavioural and computational approaches for defining imprecise regions

People often communicate with reference to informally agreed places, such as “the city centre”. However, views of the spatial extent of such areas may vary, resulting in imprecise regions. We compare perceptions of Sheffield’s City Centre from a street survey to extents derived from various web-based sources. Such automated approaches have advantages of speed, cost and repeatability. We show that footprints from web sources are often in concordance with models derived from more labour-intensive methods. Notable exceptions however were found with sources advertising or selling residential property. Agreement between sources was measured by aggregating them to identify locations of consensus.     

Spatial working memory is enhanced for movement experts in traditional and embodied tasks

Movement experts tend to outperform non-experts on some tasks of spatial ability, suggesting that movement experts possess enhanced spatial-cognitive abilities, which may be developed over years of practice. In the current study, movement experts (dancers and athletes) and non-experts completed one verbal working memory task and two spatial working memory tasks—a traditional Corsi block-tapping task and a new full-bodied version of the Corsi task, nicknamed the “Twister Task.” Movement experts outperformed non-experts on both the Corsi and Twister tasks but not on the verbal task, suggesting that movement experience may relate to spatial working memory specifically. Additionally, the Twister task significantly correlated with the traditional Corsi task, providing validation for a new measure of spatial working memory.     

极化敏感阵列的空间谱估计测向技术研究

传统的空间谱估计测向模型中没有考虑来波极化这一维度的信息,将其用于极化敏感阵列进行测向时会导致测向的灵敏度和精度下降。为此,对传统的空间谱估计测向模型进行了修正,加入对来波极化信息的考虑,提出一种极化敏感阵列的空间谱估计测向技术,并对该技术的可行性进行了研究。给出极化敏感阵列的空间谱估计测向模型,在此基础上,采用M USIC算法进行测向,并对影响测向精度的因素进行仿真。仿真结果表明,提出的极化敏感阵列空间谱估计测向技术可以实现极化敏感阵列的测向,所得结果对极化敏感阵列的测向问题具有重要意义。     

相干信源DOA估计的非对称加权空间平滑差分算法

提出了相干信源DOA估计的非对称加权空间平滑差分(UWSSD)算法。在空间平滑差分运算的基础上,对各子阵协方差矩阵采用非对称权值加权处理,破坏差分矩阵的负反对称特性,从而使信源差分协方差矩阵恢复为满秩。差分矩阵中不含相关噪声及非相关源信息,可利用它分辨相关及相干信源,而利用传统子空间算法分辨非相干信源,从而重复利用阵列接收数据,可分辨更多信源。通过分析差分矩阵的特点,提出了一种无需矩阵特征分解的快速算法。仿真结果表明,UWSSD算法具有较强的噪声抑制能力及信源过载能力。     

基于模糊SDG模型的航天器故障诊断方法研究

基于符号有向图(SDG)的故障诊断具有良好的完备性、易于解释性,但是其不足为 分辨 率差,因此,提出了基于模糊SDG模型和模糊推理相结合的半定量故障诊断方法。将节点 变 量变为模糊变量使节点承载了更多的定量信息,节点间的定性关系通过模糊关系矩阵来表达 ,通过模糊推理判断相容支路找出故障源候选集合,通过部件故障概率和传播故障权重对候 选故障源进行故障可能性的排序。最后应用该方法建立了某卫星一次电源系统的诊断模型, 并进行了故障诊断仿真,结果表明该方法有效地提高了诊断的分辨率,适用于航天器在轨 故障诊断。     

固体火箭发动机质量评判系统研究开发中的非精确推理

介绍了固体火箭发动机质量评判的特点，以带有两种典型伤情缺陷的固体火箭发动机为例，对主观Bayes非精确推理方法在固体火箭发动机质量评判中的应用进行了分析研究，给出了非精确推理框图，并简要介绍了研究推理规划中的充分性度量LS、必要性度量LN和前提的可信度C（E，S），以及计算多种伤情缺陷作用下发动机禁用的后验概率的方法。     

Learning relative directions between landmarks in a desktop virtual environment

This study presents two experiments that examine howindividuals learn relative directions betweenlandmarks in a desktop virtual environment. Subjectswere presented snapshot images of different virtualenvironments containing distinguishing landmarks anda road network. Following the presentation of eachvirtual environment, subjects were given a relativedirection test. The relative direction test involvedindicating the direction of hidden landmarks fromdifferent vantage points in the environment. Half ofthese vantage points were presented during thelearning phase, while the other half were novel.Results showed that subjects learned relativedirections between landmarks equally well when sceneswere presented in either a sequential or random order.Furthermore, viewing a configuration of landmarks ina desktop virtual environment from multipleperspectives produced a viewpoint dependentrepresentation in memory. Subjects had significantlygreater response times for new viewing perspectives,as compared to previously viewed scenes. Thisviewpoint dependent representation of the environmentpersisted despite learning under conditions ofspatio-temporal discontinuity and changes to anenvironmental frame of reference.     

Context Affects Scale Selection for Proximity Terms

Abstract

Spatial proximity terms, such as near and far, communicate information regarding the distance in which a “located” object can be found with respect to a “reference” object. The present paper investigates whether people take into account the location of an object extraneous to the located object and reference object pair, when setting the scale for proximity language judgements. Across three experiments participants rated the appropriateness of near and far to describe spatial scenes that included a third (distractor) object positioned the same distance as the located object from the reference object, but at varying distances from the located object. The results show that the presence of other spatial relations affects scale setting, resulting in differences in appropriateness ratings for those spatial terms.