Search results for "generalization"
showing 10 items of 250 documents
Time-dependent Kohn-Sham approach to quantum electrodynamics
2010
We prove a generalization of the van Leeuwen theorem towards quantum electrodynamics, providing the formal foundations of a time-dependent Kohn-Sham construction for coupled quantized matter and electromagnetic fields. Thereby we circumvent the symmetry-causality problems associated with the action-functional approach to Kohn-Sham systems. We show that the effective external four-potential and four-current of the Kohn-Sham system are uniquely defined and that the effective four-current takes a very simple form. Further we rederive the Runge-Gross theorem for quantum electrodynamics.
Insights from a Simulation Model of Disaster Response: Generalization and Action Points
2016
In a prior paper we presented a system dynamics model that simulates responder behavior in a Norwegian landslide. The model shows how a set of vicious feedback loops caused by following standard organizational procedures that do not fit the disaster situation initially increases errors in response. Eventually learning and sensemaking in an improvisation/experimentation process leads to new emergent dynamics whereby the loops act virtuously. In this paper we aim to generalize this initial study by explaining in more detail how the model can describe large scale disaster responses of different types and how it relates to the wider disaster response literature. We discuss what types of levers,…
Learning and generalizing new nouns
2021
When they learn a new word, young children need to understand which are the relevant dimensions. The relevant dimensions are not always very salient, whereas salient properties might be conceptually irrelevant. This review illustrates the benefits of comparing simltaneously two (or more) examples introduced as members of the same category. This situation has been shown to be more effective for understanding the dimension relevance than the presentation of a single example or of several items introduced sequentially. We present studies showing that situations in which training examples are given are more effective than situations in which the examples are not labelled. We also include compar…
A new methodology for distribution systems faults identification, location and characterization
2005
PurposeIdentify a new methodology for fault characterization, identification and location in electrical distribution systems, based on the use of matrix algebra.Design/methodology/approachThe developed diagnostic methodology is based on a high precision analytical model of the network using a distributed parameters representation.FindingsTest results have proved the approach to be efficient and precise, while providing a generalized quadripolar model of a line affected by the most common kinds of fault.Research limitations/implicationsGeneralization to a greater number of fault cases, experimental tests.Practical implicationsUtilities are quite interested in such items, since the new requir…
Some Necessary Revisions of the Neuronal Model Concept of the Orienting Response
1978
Sokolov's neural trace model as well as his entropy model of the orienting response are examined. Both seem inadequate for empirical and theoretical reasons. The role of the relevance aspect of a stimulus is stressed. It is proposed to consider the information transmitted by a stimulus as in some way being weighted by the relevance of the context to which it belongs. It is furthermore proposed to restrict the neural trace concept to the physical properties of the stimulus. Major theoretical gain is achieved by viewing information content of a stimulus and its physical properties independently and by breaking the motivation determining the strength of an orienting response into a situation-s…
Monotonicity properties of zeros of generalized Airy functions
1988
We show, among other things, that the positive zeros of a solution ofy ″+x α y=0,y(0)=0 decrease to 1 asα increases, 0〈α〈∞.
Conditioned generalisation in generalised anxiety disorder: the role of concurrent perceptual and conceptual cues
2021
Previous research in extinction indicates no difference in US expectancies for aversive and non-aversive unconditioned stimuli (USs). In this study, we bridged these topics by examining how concurrent perceptual and conceptual cues influence conditioned generalisation of generalised anxiety disorder (GAD) patients by using non-aversive USs. The study included two consecutive phases: acquisition and generalisation. In the acquisition phase, we used blue and purple images as the perceptually conditioned stimuli, images of animals and household items as the conceptually conditioned stimuli, and non-aversive images as unconditioned stimuli (US). In the generalisation phase, we used images conta…
USE-Net: Incorporating Squeeze-and-Excitation blocks into U-Net for prostate zonal segmentation of multi-institutional MRI datasets
2019
Prostate cancer is the most common malignant tumors in men but prostate Magnetic Resonance Imaging (MRI) analysis remains challenging. Besides whole prostate gland segmentation, the capability to differentiate between the blurry boundary of the Central Gland (CG) and Peripheral Zone (PZ) can lead to differential diagnosis, since tumor's frequency and severity differ in these regions. To tackle the prostate zonal segmentation task, we propose a novel Convolutional Neural Network (CNN), called USE-Net, which incorporates Squeeze-and-Excitation (SE) blocks into U-Net. Especially, the SE blocks are added after every Encoder (Enc USE-Net) or Encoder-Decoder block (Enc-Dec USE-Net). This study ev…
Deep Learning Based Cardiac MRI Segmentation: Do We Need Experts?
2021
Deep learning methods are the de facto solutions to a multitude of medical image analysis tasks. Cardiac MRI segmentation is one such application, which, like many others, requires a large number of annotated data so that a trained network can generalize well. Unfortunately, the process of having a large number of manually curated images by medical experts is both slow and utterly expensive. In this paper, we set out to explore whether expert knowledge is a strict requirement for the creation of annotated data sets on which machine learning can successfully be trained. To do so, we gauged the performance of three segmentation models, namely U-Net, Attention U-Net, and ENet, trained with dif…
Forrelation
2014
We achieve essentially the largest possible separation between quantum and classical query complexities. We do so using a property-testing problem called Forrelation, where one needs to decide whether one Boolean function is highly correlated with the Fourier transform of a second function. This problem can be solved using 1 quantum query, yet we show that any randomized algorithm needs Ω(√(N)log(N)) queries (improving an Ω(N[superscript 1/4]) lower bound of Aaronson). Conversely, we show that this 1 versus Ω(√(N)) separation is optimal: indeed, any t-query quantum algorithm whatsoever can be simulated by an O(N[superscript 1-1/2t])-query randomized algorithm. Thus, resolving an open questi…