TY - JOUR A1 - Hirth, Matthias A1 - Seufert, Michael A1 - Lange, Stanislav A1 - Meixner, Markus A1 - Tran-Gia, Phuoc T1 - Performance evaluation of hybrid crowdsensing and fixed sensor systems for event detection in urban environments JF - Sensors N2 - Crowdsensing offers a cost-effective way to collect large amounts of environmental sensor data; however, the spatial distribution of crowdsensing sensors can hardly be influenced, as the participants carry the sensors, and, additionally, the quality of the crowdsensed data can vary significantly. Hybrid systems that use mobile users in conjunction with fixed sensors might help to overcome these limitations, as such systems allow assessing the quality of the submitted crowdsensed data and provide sensor values where no crowdsensing data are typically available. In this work, we first used a simulation study to analyze a simple crowdsensing system concerning the detection performance of spatial events to highlight the potential and limitations of a pure crowdsourcing system. The results indicate that even if only a small share of inhabitants participate in crowdsensing, events that have locations correlated with the population density can be easily and quickly detected using such a system. On the contrary, events with uniformly randomly distributed locations are much harder to detect using a simple crowdsensing-based approach. A second evaluation shows that hybrid systems improve the detection probability and time. Finally, we illustrate how to compute the minimum number of fixed sensors for the given detection time thresholds in our exemplary scenario. KW - crowdsensing KW - event detection KW - detection time simulation KW - performance analysis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-245245 SN - 1424-8220 VL - 21 IS - 17 ER - TY - BOOK A1 - Tran-Gia, Phuoc A1 - Hoßfeld, Tobias T1 - Performance Modeling and Analysis of Communication Networks BT - A Lecture Note N2 - This textbook provides an introduction to common methods of performance modeling and analysis of communication systems. These methods form the basis of traffic engineering, teletraffic theory, and analytical system dimensioning. The fundamentals of probability theory, stochastic processes, Markov processes, and embedded Markov chains are presented. Basic queueing models are described with applications in communication networks. Advanced methods are presented that have been frequently used in recent practice, especially discrete-time analysis algorithms, or which go beyond classical performance measures such as Quality of Experience or energy efficiency. Recent examples of modern communication networks include Software Defined Networking and the Internet of Things. Throughout the book, illustrative examples are used to provide practical experience in performance modeling and analysis. Target group: The book is aimed at students and scientists in computer science and technical computer science, operations research, electrical engineering and economics. N2 - Dieses Lehrbuch bietet eine Einführung in gängige Methoden zur Modellbildung und analytische Leistungsbewertung von Kommunikationssystemen. Diese Methoden bilden die Grundlage für Verkehrstheorie und Systemdimensionierung. Die Grundlagen der Wahrscheinlichkeitstheorie, stochastische Prozesse, Markov-Prozesse und eingebettete Markov-Ketten werden vorgestellt. Grundlegende Warteschlangenmodelle werden mit Anwendungen aus Kommunikationsnetzwerken beschrieben. Es werden auch weiterführende Methoden vorgestellt, die in der jüngeren Praxis häufig verwendet wurden, insbesondere zeitdiskrete Analysealgorithmen, oder QoE und Energieeffizienz. Aktuelle Beispiele für moderne Kommunikationsnetze sind Software Defined Networking oder das Internet der Dinge. Im gesamten Buch werden anschauliche Beispiele verwendet, um praktische Erfahrungen in der Leistungsmodellierung und -analyse zu vermitteln. Zielgruppe: Das Buch richtet sich an Studierende und WissenschaftlerInnen aus den Bereichen Informatik und technische Informatik, Operations Research, Elektrotechnik und Wirtschaftswissenschaft. KW - performance modeling KW - Markovian and Non-Markovian systems KW - discrete-time models and analysis KW - communication networks KW - communication network KW - performance evaluation KW - Markov model KW - stochastic processes KW - queueing theory Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241920 SN - 978-3-95826-152-5 SN - 978-3-95826-153-2 N1 - Parallel erschienen als Druckausgabe in Würzburg University Press, 978-3-95826-152-5, 65,00 Euro. PB - Würzburg University Press CY - Würzburg ET - 1st edition ER -