Multi-Source Spatial Entity Linkage

Besides the traditional cartographic data sources, spatial information can also be derived from location-based sources. However, even though different location-based sources refer to the same physical world, each one has only partial coverage of the spatial entities, describe them with different attributes, and sometimes provide contradicting information. Hence, we introduce the spatial entity linkage problem, which finds which pairs of spatial entities belong to the same physical spatial entity. Our proposed solution (QuadSky) starts with a time-efficient spatial blocking technique (QuadFlex), compares pairwise the spatial entities in the same block, ranks the pairs using Pareto optimality with the SkyRank algorithm, and finally, classifies the pairs with our novel SkyEx-* family of algorithms that yield 0.85 precision and 0.85 recall for a manually labeled dataset of 1,500 pairs and 0.87 precision and 0.6 recall for a semi-manually labeled dataset of 777,452 pairs. Moreover, we provide a theoretical guarantee and formalize the SkyEx-FES algorithm that explores only 27% of the skylines without any loss in F-measure. Furthermore, our fully unsupervised algorithm SkyEx-D approximates the optimal result with an F-measure loss of just 0.01. Finally, QuadSky provides the best trade-off between precision and recall, and the best F-measure compared to the existing baselines and clustering techniques, and approximates the results of supervised learning solutions

The Linear Point: A cleaner cosmological standard ruler

We show how a characteristic length scale imprinted in the galaxy two-point correlation function, dubbed the "linear point", can serve as a comoving cosmological standard ruler. In contrast to the Baryon Acoustic Oscillation peak location, this scale is constant in redshift and is unaffected by non-linear effects to within $0.5$ percent precision. We measure the location of the linear point in the galaxy correlation function of the LOWZ and CMASS samples from the Twelfth Data Release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS) collaboration. We combine our linear-point measurement with cosmic-microwave-background constraints from the Planck satellite to estimate the isotropic-volume distance $D_{V}(z)$, without relying on a model-template or reconstruction method. We find $D_V(0.32)=1264\pm 28$ Mpc and $D_V(0.57)=2056\pm 22$ Mpc respectively, consistent with the quoted values from the BOSS collaboration. This remarkable result suggests that all the distance information contained in the baryon acoustic oscillations can be conveniently compressed into the single length associated with the linear point.Comment: The optimal two-point correlation function bin-size is employed. Results are updated and the distance constraints are improve

An integrated opto-mechanical measurement system for in-process defect measurement on a roll-to-roll process

This paper reports on the recent work carried out to develop and implement a high precision on-line optical measurement system with the aim of providing defect detection and characterisation for ALD coated vapour barrier films produced by a roll-to-roll process. This proof-of-concept system is designed to detect and measure pre-existing defects on the film and define their size, location, form and density. The aim is to be able to detect defects in a thin film Al2O3 layer that are critical to vapour barrier performance, and eventually provide valuable process control information. Such an inspection system must be fast in order to evaluate large areas involved (500 mm width foil) at high magnifications. In addition the flexibility of the foil introduces challenges in terms of dealing with surface deviation away from an ideal plane and vibrations. Our solution is a wavelength scanning interferometer (WSI) combined with two kinematic stages, vertical (for auto-focus) and a traverse stage to provide full coverage of the foil. A porous air-bearing conveyor system is used to hold the foil at a fixed height and improve the flatness of the film relative to the measurement plane. This paper describes the principle and design of the inspection system

Examining Perceptual and Categorical Influences on Visual Working Memory

Visual working memory (VWM) refers to the limited capacity storage of visual information used for behaviors like problem-solving, planning, or reasoning. VWM is a crucial component of cognition, and individual differences in capacity during childhood have been linked to outcomes in academic achievement, fluid intelligence, and socioemotional development. VWM increases in capacity and precision throughout development. Very few studies have investigated what factors influence changes in VWM abilities in preschool-aged children. The first goal of this study was to examine VWM precision development in this age-range. This was accomplished by administering a delayed estimation task. In this task, children touched a color wheel to indicate the color of an item in memory from a two-item array. Mixture modeling was used to measure the likelihood of reporting the target color and precision of the color represented in memory. The second goal of this project was to investigate the underlying neural, perceptual, and categorical mechanisms of VWM development. To measure perceptual mechanisms, children completed a discrimination task where they touched a color wheel to indicate the color of a visually presented color. For categorical mechanisms, children completed production and comprehension tasks for colors. To assess comprehension, children touched a color wheel to indicate the location of ‘blue’ and ‘green’. Lastly, for production, children provided ‘blue’ or ‘green’ labels for stimuli that were randomly sampled between canonical blue and green color values. Forty-four children aged 36-48 months completed these tasks across two sessions, as well as nine adults. Results showed deactivation across the delayed estimation and discrimination tasks in left postcentral gyrus, as well as activation for both in right middle temporal gyrus. In addition, right inferior gyrus was more strongly activated for the discrimination task, and left inferior frontal gyrus was more strongly activated for the delayed estimation task. Activation during both tasks was associated with behavioral measures such as the location of children’s color category boundary during production, suggesting a relationship between VWM precision and perceptual and categorical mechanisms

The development of perceptual averaging: Efficiency metrics in children and adults using a multiple-observation sound-localization task

This study examined the ability of older children to integrate spatial information across sequential observations of bandpass noise. In experiment I, twelve adults and twelve 8-14 yr olds localized 1-5 sounds, all presented at the same location along a 34° speaker array. Rate of gain in response precision (as a function of N observations) was used to measure integration efficiency. Children were no worse at localizing a single sound than adults, and - unexpectedly - were no less efficient at integrating information across observations. Experiment II repeated the task using a Reverse Correlation paradigm. The number of observations was fixed (N = 5), and the location of each sound was independently randomly jittered. Relative weights were computed for each observation interval. Distance from the ideal weight-vector was used to index integration efficiency. The data showed that children were significantly less efficient integrators than adults: only reaching adult-like performance by around 11 yrs. The developmental effect was small, however, relative to the amount of individual variability, with some younger children exhibiting greater efficiency than some adults. This work indicates that sensory integration continues to mature into late childhood, but that this development is relatively gradual

Positional information, in bits

Cells in a developing embryo have no direct way of "measuring" their physical position. Through a variety of processes, however, the expression levels of multiple genes come to be correlated with position, and these expression levels thus form a code for "positional information." We show how to measure this information, in bits, using the gap genes in the Drosophila embryo as an example. Individual genes carry nearly two bits of information, twice as much as expected if the expression patterns consisted only of on/off domains separated by sharp boundaries. Taken together, four gap genes carry enough information to define a cell's location with an error bar of ~1% along the anterior-posterior axis of the embryo. This precision is nearly enough for each cell to have a unique identity, which is the maximum information the system can use, and is nearly constant along the length of the embryo. We argue that this constancy is a signature of optimality in the transmission of information from primary morphogen inputs to the output of the gap gene network

Algorithms for Minimum Risk Chunking

Stochastic finite automata are useful for identifying substrings (chunks) within larger units of text. Relevant applications include tokenization, base-NP chunking, named entity recognition, and other information extraction tasks. For a given input string, a stochastic automaton represents a probability distribution over strings of labels encoding the location of chunks. For chunking and extraction tasks, the quality of predictions is evaluated in terms of precision and recall of the chunked/extracted phrases when compared against some gold standard. However, traditional methods for estimating the parameters of a stochastic finite automaton and for decoding the best hypothesis do not pay attention to the evaluation criterion, which we take to be the well-known F-measure. We are interested in methods that remedy this situation, both in training and decoding. Our main result is a novel algorithm for efficiently evaluating expected F-measure. We present the algorithm and discuss its applications for utility/ risk-based parameter estimation and decoding

Human Mobility Prediction Through Twitter.

Abstract Social media, in recent years, have become an invaluable source of information concerning human dynamics within urban context, allowing to enhance the comprehension of people behaviour, including human mobility regularities. The paper presents an approach to predict human mobility by exploiting Twitter data. The prediction approach is based on a novel trajectory pattern similarity measure that allows to identify the more suitable historic patterns to exploit for the prediction of the user next location. The pattern with the highest similarity to the user current trajectory will be used to predict the user next position. The experimental results obtained by using a real-world dataset show that the proposed method is effective in predicting the users next places achieving a remarkable precision