Real-World Repetition Estimation by Div, Grad and Curl

We consider the problem of estimating repetition in video, such as performing push-ups, cutting a melon or playing violin. Existing work shows good results under the assumption of static and stationary periodicity. As realistic video is rarely perfectly static and stationary, the often preferred Fourier-based measurements is inapt. Instead, we adopt the wavelet transform to better handle non-static and non-stationary video dynamics. From the flow field and its differentials, we derive three fundamental motion types and three motion continuities of intrinsic periodicity in 3D. On top of this, the 2D perception of 3D periodicity considers two extreme viewpoints. What follows are 18 fundamental cases of recurrent perception in 2D. In practice, to deal with the variety of repetitive appearance, our theory implies measuring time-varying flow and its differentials (gradient, divergence and curl) over segmented foreground motion. For experiments, we introduce the new QUVA Repetition dataset, reflecting reality by including non-static and non-stationary videos. On the task of counting repetitions in video, we obtain favorable results compared to a deep learning alternative

Reduced Deadtime and Higher Rate Photon-Counting Detection using a Multiplexed Detector Array

We present a scheme for a photon-counting detection system that can be operated at incident photon rates higher than otherwise possible by suppressing the effects of detector deadtime. The method uses an array of N detectors and a 1-by-N optical switch with a control circuit to direct input light to live detectors. Our calculations and models highlight the advantages of the technique. In particular, using this scheme, a group of N detectors provides an improvement in operation rate that can exceed the improvement that would be obtained by a single detector with deadtime reduced by 1/N, even if it were feasible to produce a single detector with such a large improvement in deadtime. We model the system for continuous and pulsed light sources, both of which are important for quantum metrology and quantum key distribution applications.Comment: 6 figure

Untangling the concept of coercive control: Theorizing domestic violent crime

The paper assesses three approaches to domestic violence: two that use the concept of ‘coercive control’ and one that uses ‘domestic violent crime’. These are: Stark’s concept of coercive control; Johnson’s distinction between situational couple violence and intimate terrorism, in which coercive control is confined to the latter; and that of domestic violent crime, in which all physical violence is conceptualised as coercive and controlling. The paper assesses these three approaches on seven issues. It offers original analysis of data from the Crime Survey for England and Wales concerning variations in repetition and seriousness in domestic violent crime. It links escalation in domestic violent crime to variations in the economic resources of the victim. It concludes that the concept of domestic violent crime is preferable to that of coercive control when seeking to explain variations in domestic violence

Probing subtle fluorescence dynamics in cellular proteins by streak camera based Fluorescence Lifetime Imaging Microscopy

We report the cell biological applications of a recently developed multiphoton fluorescence lifetime imaging microscopy system using a streak camera (StreakFLIM). The system was calibrated with standard fluorophore specimens and was shown to have high accuracy and reproducibility. We demonstrate the applicability of this instrument in living cells for measuring the effects of protein targeting and point mutations in the protein sequence which are not obtainable in conventional intensity based fluorescence microscopy methods. We discuss the relevance of such time resolved information in quantitative energy transfer microscopy and in measurement of the parameters characterizing intracellular physiology

Quantitative Imaging of Protein-Protein Interactions by Multiphoton Fluorescence Lifetime Imaging Microscopy using a Streak camera

Fluorescence Lifetime Imaging Microscopy (FLIM) using multiphoton excitation techniques is now finding an important place in quantitative imaging of protein-protein interactions and intracellular physiology. We review here the recent developments in multiphoton FLIM methods and also present a description of a novel multiphoton FLIM system using a streak camera that was developed in our laboratory. We provide an example of a typical application of the system in which we measure the fluorescence resonance energy transfer between a donor/acceptor pair of fluorescent proteins within a cellular specimen.Comment: Overview of FLIM techniques, StreakFLIM instrument, FRET application

Remembering 'zeal' but not 'thing':reverse frequency effects as a consequence of deregulated semantic processing

More efficient processing of high frequency (HF) words is a ubiquitous finding in healthy individuals, yet frequency effects are often small or absent in stroke aphasia. We propose that some patients fail to show the expected frequency effect because processing of HF words places strong demands on semantic control and regulation processes, counteracting the usual effect. This may occur because HF words appear in a wide range of linguistic contexts, each associated with distinct semantic information. This theory predicts that in extreme circumstances, patients with impaired semantic control should show an outright reversal of the normal frequency effect. To test this prediction, we tested two patients with impaired semantic control with a delayed repetition task that emphasised activation of semantic representations. By alternating HF and low frequency (LF) trials, we demonstrated a significant repetition advantage for LF words, principally because of perseverative errors in which patients produced the previous LF response in place of the HF target. These errors indicated that HF words were more weakly activated than LF words. We suggest that when presented with no contextual information, patients generate a weak and unstable pattern of semantic activation for HF words because information relating to many possible contexts and interpretations is activated. In contrast, LF words tend are associated with more stable patterns of activation because similar semantic information is activated whenever they are encountered

Subitizing with Variational Autoencoders

Numerosity, the number of objects in a set, is a basic property of a given visual scene. Many animals develop the perceptual ability to subitize: the near-instantaneous identification of the numerosity in small sets of visual items. In computer vision, it has been shown that numerosity emerges as a statistical property in neural networks during unsupervised learning from simple synthetic images. In this work, we focus on more complex natural images using unsupervised hierarchical neural networks. Specifically, we show that variational autoencoders are able to spontaneously perform subitizing after training without supervision on a large amount images from the Salient Object Subitizing dataset. While our method is unable to outperform supervised convolutional networks for subitizing, we observe that the networks learn to encode numerosity as basic visual property. Moreover, we find that the learned representations are likely invariant to object area; an observation in alignment with studies on biological neural networks in cognitive neuroscience

In Defense of Alain Badiou

In lieu of an abstract, here are the article\u27s first two paragraphs: In Issue 107, Philosophy Now published James Alexander’s ‘A Refutation of Snails by Roast Beef\u27, an article decrying con temporary French philosopher Alain Badiou (b.l937). Alexander’s jumping-off point was Roger Scruton’s unfavorable review of Badiou’s The Adventure of French Philosophy (2012). He acknowledges that Scruton “obviously dislikes everything Badiou stands for” but takes Scruton to task for being too polite; he writes that “Badiou deserves derision.” A few sentences later, he claims that “a lot of Badiou is rubbish. There is nothing to Badiou be done with it except laugh.” Not even Badiou’s students escape Alexander’s comments: he scoffs that instead of taking notes in Badiou’s lectures, surely the students “just stand and cheer.” Although I might get much enjoyment from indulging in a similarly dismissive attitude toward Alexander’s largely ad hominem attacks against Badiou, I have chosen a different path in defending him. I honor the dialectical process of Socrates’ philosophical approach; therefore I offer a counterargument to expose the inaccuracy of Alexander’s underestimation of Badiou. I will not advance uninformed opinions based on insufficient familiarity (Alexander confesses a lack of knowledge of Badiou’s oeuvre). Instead, I offer a perspective based on an engagement with and a deep reverence for Badiou’s philosophy