Efficient transmission schemes are presented for streaming scalable video over a link with limited capacity. The objective is to select a transmission sequence of data units and their transmission schedule such that the overall video quality is maximized. For video with a single spatial layer, optimal transmission schemes are obtained for two general classes of hierarchical prediction structures, which include the popular dyadic structure. Based on a new characterization of the interdependence among frames in terms of trees, structural properties of an optimal transmission schedule are derived. These properties lead to the development of a jointly optimal frame selection and scheduling algorithm, which has computational complexity that is quadratic in the number of frames. Then, using the concept of virtual deadlines, an efficient sub-optimal scheme for the transmission of video with multiple spatial layers is proposed. Simulation results show that the proposed schemes substantially outperform two existing alternatives.

Efficient transmission schemes are presented for streaming scalable video over a link with limited capacity. The objective is to select a transmission sequence of data units and their transmission schedule such that the overall video quality is maximized. For video with a single spatial layer, optimal transmission schemes are obtained for two general classes of hierarchical prediction structures, which include the popular dyadic structure. Based on a new characterization of the interdependence among frames in terms of trees, structural properties of an optimal transmission schedule are derived. These properties lead to the development of a jointly optimal frame selection and scheduling algorithm, which has computational complexity that is quadratic in the number of frames. Then, using the concept of virtual deadlines, an efficient sub-optimal scheme for the transmission of video with multiple spatial layers is proposed. Simulation results show that the proposed schemes substantially outperform two existing alternatives.

abstract: Cardiovascular disease (CVD) is the leading cause of mortality yet largely preventable, but the key to prevention is to identify at-risk individuals before adverse events. For predicting individual CVD risk, carotid intima-media thickness (CIMT), a noninvasive ultrasound method, has proven to be valuable, offering several advantages over CT coronary artery calcium score. However, each CIMT examination includes several ultrasound videos, and interpreting each of these CIMT videos involves three operations: (1) select three enddiastolic ultrasound frames (EUF) in the video, (2) localize a region of interest (ROI) in each selected frame, and (3) trace the lumen-intima interface and the media-adventitia interface in each ROI to measure CIMT. These operations are tedious, laborious, and time consuming, a serious limitation that hinders the widespread utilization of CIMT in clinical practice. To overcome this limitation, this paper presents a new system to automate CIMT video interpretation. Our extensive experiments demonstrate that the suggested system significantly outperforms the state-of-the-art methods. The superior performance is attributable to our unified framework based on convolutional neural networks (CNNs) coupled with our informative image representation and effective post-processing of the CNN outputs, which are uniquely designed for each of the above three operations. / Dissertation/Thesis / Masters Thesis Computer Science 2016

Der Beitrag untersucht die Wirkung verschiedener Einflussfaktoren auf die Perzeption von Unordnung. Einer Einführung in die theoretische Diskussion rund um die Wirkung von Unordnung auf das urbane Sozialgefüge folgen verschiedene multivariate Berechnungen (N = 2003). Hierzu wird ein additiver Index aus dem Produkt von subjektiver Schwere und perzipierter Häufigkeit verschiedener Erscheinungsformen physischer und sozialer Unordnung gebildet. Die Regressionsergebnisse zeigen, dass die soziale Struktur urbaner Nachbarschaften, der bedingte Erwartungswert für die kollektive Wirksamkeit informeller Sozialkontrolle sowie solche Prädiktoren, welche die Bedeutung des unmittelbaren sozialen Nahraumes für Prozesse kognitiver Dissonanzbewältigung betonen (Viktimisierung, Wohnverhältnis, Kriminalitätseinstellungen), erklären, wann ein Akteur eine Situation als unsicher definiert und infolgedessen Unordnung als Anzeichen von Gefahr interpretiert. Der dem Explanans zugrundeliegende soziale Mechanismus beruht auf der Theorie der Frame-Selektion nach Esser (1991). Die Untersuchung basiert auf der Sicherheitsbefragung der Stadt Leipzig (2011).:1 Einleitung 2 Theorie 2.1 Hunter (1978) 2.2 Wilson und Kelling (1982) 2.3 Exkurs 2.4 Lewis und Salem (1986) 2.5 Skogan (1990) 2.6 Das Konzept der collective efficacy 3 Hypothesen 3.1 Der Grundzusammenhang des theoretischen Modells 3.2 Die Brückenhypothesen des Modells 3.2.1 Direkte und indirekte Viktimisierung 3.2.2 Kriminalitätsfurcht 3.2.3 Medienrezeption 3.2.4 Kontrollvariablen 4 Daten, Operationalisierungen, Methoden 4.1 Daten 4.2 Operationalisierungen 4.2.1 Abhängige Variable(n) 4.2.2 Unabhängige Variablen 4.3 Methoden 5 Auswertung 5.1 Bivariate Ergebnisse 5.2 Multivariate Ergebnisse 6 Fazit und abschließende Bemerkungen 7 Anhang 8 Literaturverzeichnis / This article investigates the influence of various predictors on the perception of disorder. An introduction to the theoretical discussion about the impact of disorder on the urban social structure is followed by different multivariate regressions (N = 2003). The perception of different images of physical and social disorder is measured in terms of the sentimental value of disorder and the perceived frequency of disorder. An additive index using product terms of the sentimental value and the perceived frequency for each image is constructed. The results of the regressions indicate that social structure of urban neighborhoods, collective efficacy, and such predictors which aim at the significance of social proximity (victimization, housing situation, personal crime settings) for processes of cognitive dissonance coping explain when an actor defines a situation as not-secure and subsequently interprets disorder as a symbol of danger. Esser’s (1991) theory of frame-selection functions as the social mechanism of the explanans. The hypotheses are tested on survey data provided by the city of Leipzig (2011).:1 Einleitung 2 Theorie 2.1 Hunter (1978) 2.2 Wilson und Kelling (1982) 2.3 Exkurs 2.4 Lewis und Salem (1986) 2.5 Skogan (1990) 2.6 Das Konzept der collective efficacy 3 Hypothesen 3.1 Der Grundzusammenhang des theoretischen Modells 3.2 Die Brückenhypothesen des Modells 3.2.1 Direkte und indirekte Viktimisierung 3.2.2 Kriminalitätsfurcht 3.2.3 Medienrezeption 3.2.4 Kontrollvariablen 4 Daten, Operationalisierungen, Methoden 4.1 Daten 4.2 Operationalisierungen 4.2.1 Abhängige Variable(n) 4.2.2 Unabhängige Variablen 4.3 Methoden 5 Auswertung 5.1 Bivariate Ergebnisse 5.2 Multivariate Ergebnisse 6 Fazit und abschließende Bemerkungen 7 Anhang 8 Literaturverzeichnis