SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Pattern matching

164

Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. “Crazy quilts” represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures.

Concepts: Statistics, Symmetry, Mixture, Pattern, Rotational symmetry, Pattern matching, Quilting, Quilt

138

One of the most relevant dermoscopic patterns is the pigment network. An innovative method of pattern recognition is presented for its detection in dermoscopy images.

Concepts: Pattern, Pattern recognition, Pattern matching

28

Much of the difficulty in understanding acetabular fracture patterns is due to the complex three-dimensional relationship of the acetabulum to the greater pelvis. We hypothesized that combining three-dimensional “hands-on” anatomic models with two-dimensional informational teaching sheets would improve the ability of orthopaedic residents to accurately classify acetabular fracture patterns and aid in preoperative surgical approach selection.

Concepts: Vector space, Pelvis, Pattern, Acetabulum, Pubis, Pattern recognition, Ilium, Pattern matching

7

In this paper, we define a new problem related to social media, namely, the data-driven engineering of social dynamics. More precisely, given a set of observations from the past, we aim at finding the best short-term intervention that can lead to predefined long-term outcomes. Toward this end, we propose a general formulation that covers two useful engineering tasks as special cases, namely, pattern matching and profit maximization. By incorporating a deep learning model, we derive a solution using convex relaxation and quadratic-programming transformation. Moreover, we propose a data-driven evaluation method in place of the expensive field experiments. Using a Twitter dataset, we demonstrate the effectiveness of our dynamics engineering approach for both pattern matching and profit maximization, and study the multifaceted interplay among several important factors of dynamics engineering, such as solution validity, pattern-matching accuracy, and intervention cost. Finally, the method we propose is general enough to work with multi-dimensional time series, so it can potentially be used in many other applications.

Concepts: Time, Mathematics, Economics, Term, Pattern, Pattern recognition, Pattern matching, Profit maximization

2

Recently, item responses and total scores on depression screening scales have been reported to have characteristic distributions in the general population. The distributional pattern of responses to the Patient Health Questionnaire-9 (PHQ-9) in the general population has not been well studied. Thus, we carried out a pattern analysis of the PHQ-9 item responses and total scores in US adults.

Concepts: Illness, Pattern, Pattern recognition, Pattern matching

2

Although electromyogram (EMG) pattern recognition (PR) for multifunctional upper limb prosthesis control has been reported for decades, the clinical benefits have rarely been examined. The study purposes were to: 1) compare self-report and performance outcomes of a transradial amputee immediately after training and one week after training of direct myoelectric control and EMG pattern recognition (PR) for a two-degree-of-freedom (DOF) prosthesis, and 2) examine the change in outcomes one week after pattern recognition training and the rate of skill acquisition in two subjects with transradial amputations.

Concepts: Evaluation methods, Skill, Electromyography, Learning, Amputation, Upper limb, Prosthesis, Pattern matching

2

Multivoxel pattern analysis (MVPA) has gained enormous popularity in the neuroimaging community over the past few years. At the group level, most MVPA studies adopt an “information based” approach in which the sign of the effect of individual subjects is discarded and a non-directional summary statistic is carried over to the second level. This is in contrast to a directional “activation based” approach typical in univariate group level analysis, in which both signal magnitude and sign are taken into account. The transition from examining effects in one voxel at a time vs. several voxels (univariate vs. multivariate) has thus tacitly entailed a transition from directional to non-directional signal definition at the group level. While a directional group-level MVPA approach implies that individuals have similar multivariate spatial patterns of activity, in a non-directional approach each individual may have a distinct spatial pattern. Using an experimental dataset, we show that directional and non-directional group-level MVPA approaches uncover distinct brain regions with only partial overlap. We propose a method to quantify the degree of spatial similarity in activation patterns over subjects. Applied to an auditory task, we find higher values in auditory regions compared to control regions.

Concepts: Statistics, Mathematics, Magnetic resonance imaging, Multivariate statistics, Pattern, Voxel, Pattern recognition, Pattern matching

2

We conducted this study to characterize in-flight pediatric fatalities onboard commercial airline flights worldwide and identify patterns that would have been unnoticed through single case analysis of these relative rare events.

Concepts: Northwest Airlines, Pattern matching, Aircraft, Airline, Avianca, Airlines, Southwest Airlines, Regional airline

1

Digestive symptoms are reported to result from a wide range of dietary components. Dietary pattern analysis is a useful method when considering the entire diet, rather than individual foods or nutrients, providing an opportunity to take interactions into account. The aim of the present study was to investigate, using a dietary pattern approach, the relationship between diet, digestive symptoms, and health-related quality of life (HRQoL) in women reporting minor digestive symptoms.

Concepts: Nutrition, Death, Pattern, Seafood, Pattern recognition, Bobby Hutcherson, James Spaulding, Pattern matching

1

A periodic zigzag structure of DNA material has been successfully fabricated by a simple shearing method. The periodicity of the pattern can be finely controlled by combining the mechanical shearing method with topographic patterns of microchannels. The resultant zigzag patterns can be used as a template to control the alignment of rod-like liquid crystals due to its highly regular periodicity.

Concepts: DNA, Crystal, Crystal structure, Mathematics, Liquid crystal, Pattern matching