3,297 research outputs found

    Quality of Service Aware Data Stream Processing for Highly Dynamic and Scalable Applications

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    Huge amounts of georeferenced data streams are arriving daily to data stream management systems that are deployed for serving highly scalable and dynamic applications. There are innumerable ways at which those loads can be exploited to gain deep insights in various domains. Decision makers require an interactive visualization of such data in the form of maps and dashboards for decision making and strategic planning. Data streams normally exhibit fluctuation and oscillation in arrival rates and skewness. Those are the two predominant factors that greatly impact the overall quality of service. This requires data stream management systems to be attuned to those factors in addition to the spatial shape of the data that may exaggerate the negative impact of those factors. Current systems do not natively support services with quality guarantees for dynamic scenarios, leaving the handling of those logistics to the user which is challenging and cumbersome. Three workloads are predominant for any data stream, batch processing, scalable storage and stream processing. In this thesis, we have designed a quality of service aware system, SpatialDSMS, that constitutes several subsystems that are covering those loads and any mixed load that results from intermixing them. Most importantly, we natively have incorporated quality of service optimizations for processing avalanches of geo-referenced data streams in highly dynamic application scenarios. This has been achieved transparently on top of the codebases of emerging de facto standard best-in-class representatives, thus relieving the overburdened shoulders of the users in the presentation layer from having to reason about those services. Instead, users express their queries with quality goals and our system optimizers compiles that down into query plans with an embedded quality guarantee and leaves logistic handling to the underlying layers. We have developed standard compliant prototypes for all the subsystems that constitutes SpatialDSMS

    An Approach to Calculate Exact Coverage Area for Connected Wireless Sensor Network

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    واحدة من التقنيات المتقدمة المستخدمة في أنظمة الاتصالات للشبكة الذكية هي شبكة الاستشعار اللاسلكية (WSN). WSN لديها مجموعة واسعة من التطبيقات تغطي العديد من المجالات مثل، إدارة الكوارث، اكتشاف حقل المعركة، التأمين على الحدود، مراقبة صحة المرضى، وغيرها. أن مشاكل الربط والتغطية للمستشعرات في الآونة الاخيرة لها أهمية عظيمة.  في البحث، قمنا بعرض الاتصال وتغطية العقد في WSN, تم اعداد خوارزمية لحساب مساحة التغطية المضبوطة لمجموعة عقد شبكة الاستشعار بالتوزيع المتجانس المستوي لنموذج القرص البسيط. هذه الخوارزمية تعتمد ارتباطات العقد ضمن مدى الاتصالات الاقصى للعقدة لذلك لايوجد في المساحات مناطق منفصلة. في حين تم احتساب كل المساحات غير المغطاة بالاستشعار ضمن المنطقة قيد الاهتمام (RoI) ضمن المساحة المغطاة. لذا تم احتساب النسبة المئوية للمساحة المغطاة بالضبط. ان استخدام هذه الطريقة سيكون الحجر الاساس للدراسات التي تتطلب سيطرة أفضل لنشر عقد المتحسسات. One of the advanced technologies used in the communicating systems of the intelligent grid is Wireless Sensor Network (WSN). WSN has a wide range of applications covers many fields like catastrophe management, hostilities field recognition, border insurance, patient health monitoring, and others. The sensor connectivity and coverage problems recently have a great attention. In this paper, we presented the connectivity and coverage of nodes in WSN, a new algorithm is prepared to extract exact coverage area of plain uniform depletion of node samples according to simple disk model. This algorithm considers the connection of nodes within maximum range of transmission communications, therefore no disconnected graph occurs. While uncovered area within region of interest (RoI) inside coverage area is calculated, although many uncovered regions occurred. So the coverage percentage area is calculated in an exact solution. This algorithm will be one of keystone study to better control of sensor depletion.    &nbsp

    Weiterentwicklung analytischer Datenbanksysteme

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    This thesis contributes to the state of the art in analytical database systems. First, we identify and explore extensions to better support analytics on event streams. Second, we propose a novel polygon index to enable efficient geospatial data processing in main memory. Third, we contribute a new deep learning approach to cardinality estimation, which is the core problem in cost-based query optimization.Diese Arbeit trägt zum aktuellen Forschungsstand von analytischen Datenbanksystemen bei. Wir identifizieren und explorieren Erweiterungen um Analysen auf Eventströmen besser zu unterstützen. Wir stellen eine neue Indexstruktur für Polygone vor, die eine effiziente Verarbeitung von Geodaten im Hauptspeicher ermöglicht. Zudem präsentieren wir einen neuen Ansatz für Kardinalitätsschätzungen mittels maschinellen Lernens

    The State-of-the-Art of Set Visualization

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    Sets comprise a generic data model that has been used in a variety of data analysis problems. Such problems involve analysing and visualizing set relations between multiple sets defined over the same collection of elements. However, visualizing sets is a non-trivial problem due to the large number of possible relations between them. We provide a systematic overview of state-of-the-art techniques for visualizing different kinds of set relations. We classify these techniques into six main categories according to the visual representations they use and the tasks they support. We compare the categories to provide guidance for choosing an appropriate technique for a given problem. Finally, we identify challenges in this area that need further research and propose possible directions to address these challenges. Further resources on set visualization are available at http://www.setviz.net

    Distribution and Social Structure of an Estuarine Bottlenose Dolphin (Tursiops truncatus) Population in Northern South Carolina

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    Information regarding habitat preference of apex predators may pinpoint areas dense in resources such as prey species. Knowledge of how animals use their habitat can enable the classification and targeted management of important habitat features. This study was conducted to determine the distribution and social structure of an inshore population of bottlenose dolphins within the North Inlet-Winyah Bay estuary in northern South Carolina. Photo-identification surveys were conducted along defined transect routes. Home ranges of individual dolphins were calculated using the minimum convex polygon method and the fixed kernel density method using Geographic Information System (GIS) software. Mean group sizes and coefficients of association were compared between warm and cold seasons. Coefficients of association were calculated using the half weight index. Additionally, these same social parameters were compared between dolphins using only North Inlet, those using only Winyah Bay, and those using both systems. Surveys were performed during the warm months (221 hours of survey time from May through October) and during the cold season (52 hours of survey time from December through February). The 2011-2012 population estimate for the North Inlet-Wnyah Bay population was 84, and fewer dolphins were present in the North Inlet-Winyah Bay estuary during the cold months than during the warm months. The majority of the dolphins in this study used both North Inlet and Winyah Bay. However, three individuals were sighted only in North Inlet, and 38 individuals were sighted only in Winyah Bay. Group sizes were larger in the warm season than the cold season. Dolphins that had at least 10 independent sightings associated non-randomly, and individuals in the population formed distinct communities with overlapping ranges. The mean coefficient of association was 0.24 for all dolphins with at least 10 sightings, and the associations were weaker than in most other studied populations. However, when determining mean coefficients of association within North Inlet transects (0.48) and Winyah Bay transects (0.34), the associations were similar those observed in other studies. The mean home range was 32.79 km². Home ranges were larger in the warm season than the cold season. While the kernel density method, compared to the Minimum Convex Polygon method, seems to more accurately estimate the home range of dolphins in open water systems, the small creeks in North Inlet coupled with the clipping feature in ArcGIS make the minimum convex polygon method just as accurate because dolphins had limited travel routes within the creeks

    Automatic Contact Surface Detection

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    Motion planners for humanoid robots require knowledge of all available surfaces in the environment with which the robot may make contact. We introduce a method to automatically detect these surfaces in real time in unknown environments. The system maintains a set of known planar surfaces, expressed as two dimensional polygons, and detects new surfaces and new areas of existing surfaces as the robot moves through the environment. The only required inputs are data from commonly available sensors and a small set parameters which depend only on the characteristics of the robot and sensor. In real-world environments, Surface Detection detects an initial set of surfaces within 1.5 seconds, and the average time to detect a newly-visible surface is less than two seconds

    Modeling Barcelona sidewalks: a high resolution urban scale assessment of the geometric attributes of the walkable network

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    Within the framework of urban pedestrian networks, this paper presents a method of modeling the street network from the perspective of foot traffic, beyond the vehicle-focused street centerline representation approach in transportation research. A scalable method to extract the centerlines of the complete walkable urban area from its polygon representation at a one-meter resolution is discussed, using open-source tools. To evaluate the betweenness centrality in a spatially directed graph, the process is applied to the study of the ‘walkable Barcelona’, focusing on three key parameters: 1) the street width, 2) the longitudinal slope, and 3) the crosswalks connecting the sidewalk platforms. The results identify the uneven distribution of these parameters within a complex urban fabric, and the high-resolution cartography allows the identification of critical areas within the network, introducing future lines of research and applications of the workflow. This is especially relevant considering the increasing awareness of citizens and the urban agendas worldwide, aimed at improving and widening the sidewalk infrastructure that supports local activity in cities.Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.2 - Per a 2030, proporcionar accés a sistemes de transport segurs, assequibles, accessi­bles i sostenibles per a totes les persones, i millorar la seguretat viària, en particular mitjan­çant l’ampliació del transport públic, amb especial atenció a les necessitats de les persones en situació vulnerable, dones, nenes, nens, persones amb discapacitat i persones gransObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.1 - Desenvolupar infraestructures fiables, sostenibles, resilients i de qualitat, incloent infraestructures regionals i transfrontereres, per tal de donar suport al desenvolupament econòmic i al benestar humà, amb especial atenció a l’accés assequible i equitatiu per a totes les personesPostprint (published version
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