R-tree的查询代价模型分析及算法改进

提出一个R-tree的查询代价模型（Cost Model) ,在对该模型分析的基础上，对R-tree及其变种进行了改进，形成了CR^*-tree，分别对Cost Model和CR^*-tree做了实验，结果显示该Cost Model的平均误差为12．6％，而改进后的CR^*-tree查询性能比R^*-tree提高了4．25％。     

A Filter Flow Visual Querying Language and Interface for Spatial Databases

In this paper a visual approach to querying in spatial databases is presented. A filter flow methodology is used to consistently express different types of queries in these systems. Filters are used to represent operations on the database and pictorial icons are used throughout the language for filters, operators and spatial relations. Different granularities of the relations are presented in a hierarchical fashion for spatial constraints. The language framework and functions are described and examples are used to demonstrate its capabilities in representing different levels of queries, including spatial joins and composite spatial joins. Here, the primary focus is on the query language itself but an overview of the implemented interface of the language is also provided.     

Lateralization of Spatial Learning in the Avian Hippocampal Formation.

The authors investigated lateralization of spatial learning within the avian hippocampal formation (HF). In Experiment 1, homing pigeons (Columba livia) with unilateral lesions of the right or left HF were trained to locate a goal in a square room containing local landmarks and global room cues. All groups learned the task. During probe trials, when landmarks were rotated or removed, intact pigeons and left HF-lesioned pigeons relied exclusively on global room cues to locate the food goal. Pigeons with right HF lesions were the only group to demonstrably use the landmarks. The results suggest that the right HF is preferentially involved in the representation of global environmental space, whereas only the left HF may be sensitive to local landmarks for navigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for Visuospatial Location Following Selective Hippocampal Sclerosis: The Use of Different Coordinate Systems.

This study addressed the role of the medial temporal lobe regions and, more specifically, the contribution of the human hippocampus in memory for body-centered (egocentric) and environment-centered (allocentric) spatial location. Twenty-one patients with unilateral atrophy of the hippocampus secondary to long-standing epilepsy (left, n = 7; right, n = 14) and 15 normal control participants underwent 3 tasks measuring recall of egocentric or allocentric spatial location. Patients with left hippocampal sclerosis were consistently impaired in the allocentric conditions of all 3 tasks but not in the egocentric conditions. Patients with right hippocampal sclerosis were impaired to a lesser extent and in only 2 of the 3 tasks. It was concluded that hippocampal structures are crucial for allocentric, but not egocentric, spatial memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

'It's the end of the world as we know it': Threat and the spatial-symbolic self": Correction to Burris and Rempel (2004).

Reports an error in 'It's the End of the World as We Know It': Threat and the Spatial-Symbolic Self" by Christopher T. Burris and John K. Rempel (Journal of Personality and Social Psychology, 2004[Jan], Vol 86[1], 19-42). The article contained two errors. On page 35, second column, line 14, two of the word fragments are notated incorrectly. The word shown as s[k]ull should be sk[u]ll, and the word shown as as[h]es should be as[h]e[s]. (The following abstract of the original article appeared in record 2003-11198-002.) According to amoebic self theory, the boundary defining the self encompasses 3 levels of self-representation--bodily, social, and spatial-symbolic. Study 1 related a newly developed measure of individual differences in sensitivity to boundary threat across these 3 domains to values and disgust sensitivity. Four subsequent studies focused on spatial-symbolic threat sensitivity and related it to right-wing authoritarianism, aversive reactions to unfamiliar out-groups, and revulsion to vermin. A final experiment illustrates how a salient spatial-symbolic threat (dust mites) can elicit reactions toward out-groups that closely parallel mortality salience effects observed in research inspired by terror management theory, even though dust mites do not elicit mortality concerns. The importance of preserving the familiar in order to preserve the self is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Response-Discrimination Account of the Simon Effect.

Simon effects might partly reflect stimulus-triggered response activation. According to the response-discrimination hypothesis, however, stimulus-triggered response activation shows up in Simon effects only when stimulus locations match the top-down selected spatial codes used to discriminate between alternative responses. Five experiments support this hypothesis. In Experiment 1, spatial codes of each response differed by horizontal and vertical axis position, yet one axis discriminated between alternative responses, whereas the other did not. Simon effects resulted for targets on discriminating axes only. In Experiment 2, both spatial axes discriminated between responses, and targets on both axes produced Simon effects. In Experiment 3, Simon effects resulted for a spatial choice-reaction task but not for a go/no-go task. Even in the go/no-go task, a Simon effect was restored when a two-choice reaction task preceded the go/no-go task (Experiment 4) or when participants initiated trials with responses spatially discriminated from the go response (Experiment 5). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blink and Shrink: The Effect of the Attentional Blink on Spatial Processing.

The detection or discrimination of the second of 2 targets in a rapid serial visual presentation (RSVP) task is often temporarily impaired-a phenomenon termed the attentional blink. This study demonstrated that the attentional blink also affects localization performance. Spatial cues pointed out the possible target positions in a subsequent visual search display. When cues were presented inside an attentional blink (as induced by an RSVP task), the observers' capacity to use them was reduced. This effect was not due to attention being highly focused, to general task switching costs, or to complete unawareness of the cues. Instead, the blink induced a systematic localization bias toward the fovea, reflecting what appears to be spatial compression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Watershed scale temporal and spatial stability of soil moisture and its role in validating satellite estimates

Watershed scale soil moisture estimates are necessary to validate current remote sensing products, such as those from the Advanced Microwave Scanning Radiometer (AMSR). Unfortunately, remote sensing technology does not currently resolve the land surface at a scale that is easily observed with ground measurements. One approach to validation is to use existing soil moisture measurement networks and scale these point observations up to the resolution of remote sensing footprints. As part of the Soil Moisture Experiment 2002 (SMEX02), one such soil moisture gaging system in the Walnut Creek Watershed, Iowa, provided robust estimates of the soil moisture average for a watershed throughout the summer of 2002. Twelve in situ soil moisture probes were installed across the watershed. These probes recorded soil moisture at a depth of 5 cm from June 29, 2002 to August 19, 2002. The sampling sites were analyzed for temporal and spatial stability by several measures including mean relative difference, Spearman rank, and correlation coefficient analysis. Representative point measurements were used to estimate the watershed scale (∼25 km) soil moisture average and shown to be accurate indicators with low variance and bias of the watershed scale soil moisture distribution. This work establishes the validity of this approach to provide watershed scale soil moisture estimates in this study region for the purposes of satellite validation with estimation errors as small as 3%. Also, the potential sources of error in this type of analysis are explored. This study is a first step in the implementation of large-scale soil moisture validation using existing networks such as the Soil Climate Analysis Network (SCAN) and several Agricultural Research Service watersheds as a basis for calibrating satellite soil moisture products, for networks design, and designing field experiments.     

Quantitative analysis of pore patterns on rat prostate nuclei using spatial statistics methods

Spatial statistics methods have been used to analyse the nuclear pore pattern in rat ventral prostate nuclei isolated from adult animals. The observed results show that: (1) pores on prostate nuclear membranes are not randomly distributed; (2) the data sets obtained from different micrographs are consistent with the same statistical model thus suggesting the existence of a typical pore distribution.     

Integrated solid-state nanopore devices for third generation DNA sequencing

Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA strand by merely analyzing the ionic current due to speedy DNA translocation and low spatial resolution.More integrated configurations are pursued to present versatile comparative dissimilarities of the four bases by enhancing the spatial resolution within a DNA molecule translocation event,such as transverse tunneling current,local potential change,and capacitance oriented voltage resonance.In this mini review,the insight is provided into the status quo on several functionalized techniques and methodologies for DNA sequencing and furthermore concluding remark and outlook are presented.