423 research outputs found

    SOS-Supported Graph Transformation

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    In this paper, we propose a simplicity-oriented approach for model-tomodel transformations of graphical languages. Key to simplicity is decomposing the rule system into two rule sub-systems that separate purpose-specific aspects (transformation and computation), and specifying these rule systems as a graphical language. For the transformational aspect, we use a compiler-like generation approach, while taking Plotkin’s Structural Operational Semantics (SOS) as inspiration for the computational aspect. We define these rule systems as inference rules for pattern-based transformations of typed, hierarchical graphs. Using typed graphs allows patterns to easily distinguish between the elements of the source graph. The resulting rule system (named SOS-Supported Graph Transformation, or SOS-GT) supports a well-structured and intuitive specification of complex model-to-model transformations adequate for a variety of use cases. We illustrate these rules with an example of transforming the WebStory language (WSL, an educational tool) to a Kripke Transition System (KTS) suitable for model checking, and give an overview over more applications in the end of the paper

    Signal diversity for the reduction of signal dropouts and speckle noise in a laser-Doppler extensometer

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    A recently demonstrated laser-Doppler extensometer is affected by signal dropouts caused by speckle noise, whereby the carrier-to-noise ratio (C/N) falls below the so-called frequency-modulation threshold. In this article, we present a new optical setup with polarization signal diversity for reducing speckle-induced dropouts dramatically. The probability of a signal dropout can be substantially reduced using weighted combination signals from different photodetectors collecting the scattered light at two orthogonal polarizations. Therefore, we prove in this paper that signal diversity enables a laser-Doppler extensometer for industrial applications. Furthermore, a theoretical model based on the speckle statistics for estimating the probability of signal dropout is introduced. The relationship between the occurrence of signal dropouts and the demodulation bandwidth is studied. The experimental results of the occurrence of dropouts highly match the theoretical estimated probability distribution. Finally, strain measurement demonstrates a significant reduction of speckle noise with the implemented technique

    Signal diversity for the reduction of signal dropouts and speckle noise in a laser-Doppler extensometer

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    A recently demonstrated laser-Doppler extensometer is affected by signal dropouts caused by speckle noise, whereby the carrier-to-noise ratio (C/N) falls below the so-called frequency-modulation threshold. In this article, we present a new optical setup with polarization signal diversity for reducing speckle-induced dropouts dramatically. The probability of a signal dropout can be substantially reduced using weighted combination signals from different photodetectors collecting the scattered light at two orthogonal polarizations. Therefore, we prove in this paper that signal diversity enables a laser-Doppler extensometer for industrial applications. Furthermore, a theoretical model based on the speckle statistics for estimating the probability of signal dropout is introduced. The relationship between the occurrence of signal dropouts and the demodulation bandwidth is studied. The experimental results of the occurrence of dropouts highly match the theoretical estimated probability distribution. Finally, strain measurement demonstrates a significant reduction of speckle noise with the implemented technique

    A Loss Function for Generative Neural Networks Based on Watson's Perceptual Model

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    To train Variational Autoencoders (VAEs) to generate realistic imagery requires a loss function that reflects human perception of image similarity. We propose such a loss function based on Watson's perceptual model, which computes a weighted distance in frequency space and accounts for luminance and contrast masking. We extend the model to color images, increase its robustness to translation by using the Fourier Transform, remove artifacts due to splitting the image into blocks, and make it differentiable. In experiments, VAEs trained with the new loss function generated realistic, high-quality image samples. Compared to using the Euclidean distance and the Structural Similarity Index, the images were less blurry; compared to deep neural network based losses, the new approach required less computational resources and generated images with less artifacts.Comment: Published at the 34th Conference on Neural Information Processing Systems (NeurIPS 2020

    The negative side of cohomology for Calabi-Yau categories

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    We study integer-graded cohomology rings defined over Calabi-Yau categories. We show that the cohomology in negative degree is a trivial extension of the cohomology ring in non-negative degree, provided the latter admits a regular sequence of central elements of length two. In particular, the product of elements of negative degrees are zero. As corollaries we apply this to Tate-Hochschild cohomology rings of symmetric algebras, and to Tate cohomology rings over group algebras. We also prove similar results for Tate cohomology rings over commutative local Gorenstein rings.Comment: 14 page

    Использование двухчастотного намагничивания для получения кривой дифференциальной динамической проницаемости

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    Анализ процесса перемагничивания ферромагнетика в сложном поле позволил путем разложения в ряд Фурье получить полное выражение э. д. с. измерительной обмотки датчика. Показано, что огибающая сигнала, изменяющегося с частотой возбуждающего высокочастотного поля при определенных соотношениях параметров полей, повторяют по форме временную зависимость дифференциальной динамической проницаемости. Приводится блок-схема установки, реализующей указанный метод

    Dimensions of triangulated categories via Koszul objects

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    Lower bounds for the dimension of a triangulated category are provided. These bounds are applied to stable derived categories of Artin algebras and of commutative complete intersection local rings. As a consequence, one obtains bounds for the representation dimensions of certain Artin algebras.Comment: Final revised version, to appear in Math.

    Sexualized Behavior Among Adolescents Who Sexually Offended

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    Early or excessive sexualized behaviors and preoccupations with sexuality (SB) exhibited by juveniles who have sexually offended (JSO) are considered risk factors for sexual recidivism. However, research into SB among JSO is scarce. The present study retrospectively examined prevalence rates and patterns of SB among JSO prior to sexual offending and their relation to psychopathology and sexual recidivism. We systematically assessed information from psychiatric and psychological expert reports in case files of 230 JSO aged 12–18 years (M = 14.46, SD = 1.49) from a population sample of JSO with contact sexual offenses. A total of 93 (40.4%) JSO exhibited SB prior to the index sexual offense. Latent class analysis revealed three SB profiles: (1) “low/no SB” (n = 188), (2) “preoccupied SB” (preoccupation with sexuality, e.g., early pornography consumption, excessive masturbation; n = 29), and (3) “dysregulated SB” (exhibiting inappropriate sexualized behaviors toward others, e.g., sexualized speech, touching others inappropriately; n = 13). The preoccupied SB and the dysregulated SB groups showed higher prevalence of psychiatric disorders than the low/no SB. However, none of the JSO of the preoccupied SB or dysregulated SB groups reoffended sexually within 365 days after conviction for the sexual index offense (low/no SB: 12.8%). Overall, our findings do not support a general notion of the presence of SB as an indicator of high risk for persistent sexual offending among JSO. Instead, JSO with SB appear particularly burdened regarding a range of psychiatric disorders that should be treated accordingly

    Accelerated large volume irradiation with dynamic Jaw/Dynamic Couch Helical Tomotherapy

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    BACKGROUND: Helical Tomotherapy (HT) has unique capacities for the radiotherapy of large and complicated target volumes. Next generation Dynamic Jaw/Dynamic Couch HT delivery promises faster treatments and reduced exposure of organs at risk due to a reduced dose penumbra. METHODS: Three challenging clinical situations were chosen for comparison between Regular HT delivery with a field width of 2.5 cm (Reg 2.5) and 5.0 cm (Reg 5.0) and DJDC delivery with a maximum field width of 5.0 cm (DJDC 5.0): Hemithoracic Irradiation, Whole Abdominal Irradiation (WAI) and Total Marrow Irradiation (TMI). For each setting, five CT data sets were chosen, and target coverage, conformity, integral dose, dose exposure of organs at risk (OAR) and treatment time were calculated. RESULTS: Both Reg 5.0 and DJDC 5.0 achieved a substantial reduction in treatment time while maintaining similar dose coverage. Treatment time could be reduced from 10:57 min to 3:42 min / 5:10 min (Reg 5.0 / DJDC 5.0) for Hemithoracic Irradiation, from 18:03 min to 8:02 min / 8:03 min for WAI and to 18:25 min / 18:03 min for TMI. In Hemithoracic Irradiation, OAR exposure was identical in all modalities. For WAI, Reg 2.5 resulted in lower exposure of liver and bone. DJDC plans showed a small but significant increase of ∼ 1 Gy to the kidneys, the parotid glans and the thyroid gland. While Reg 5.0 and DJDC were identical in terms of OAR exposure, integral dose was substantially lower with DJDC, caused by a smaller dose penumbra. CONCLUSIONS: Although not clinically available yet, next generation DJDC HT technique is efficient in improving the treatment time while maintaining comparable plan quality

    Physical Activity and Recurrent Pain in Children and Adolescents in Germany—Results from the MoMo Study

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    Recurrent pain can be a significant disruption in the activities of daily life, and is not only a health problem in adults but also in children and adolescents. This study analyzed the prevalence of recurrent pain in the current sample (n = 1516; 11–17 years (meanage_{age} = 14.4 ± 2.0 years); 50.8% female) of a nationwide study in Germany, evaluated the association of participants’ device-based physical activity (PA) with the prevalence of recurrent pain, and assessed whether children and adolescents who reported pain for the last three months accumulated less PA than those who did not. A higher prevalence was found in girls for recurrent headaches (42.2% vs. 28.7%), abdominal pain (28.2% vs. 20.1%), and back pain (26.9% vs. 19.5%). We found higher odds for recurrent headaches in girls (OR = 1.54) and in participants that did not reach at least 60 min of moderate to vigorous PA (MVPA) per day (OR = 2.06). Girls who reported recurrent headaches accumulated 4.7 min less MVPA per day than those without. The prevalence of pain remains at a high level in the German youth and underscores the need for interventions to improve the health situations of children and adolescents
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