164 research outputs found
"Multimedia video-based surveillance systems"
No full textMultimedia surveillance systems is an emerging field that includes signal and image processing, communications, and computer vision. Multimedia Video-Based Surveillance Systems: Requirements, Issues and Solutions, combines the most recent research results from these areas for use by engineers and end-users involved in the design of surveillance systems in the fields of transportation and services. The book covers emerging surveillance requirements, including new digital sensors for real-time acquisition of surveillance data, low-level image processing algorithms, and event detection methods. It also discusses problems related to knowledge representation in surveillance systems, wireless and wired multimedia networks, and a new generation of surveillance communication tools. Timely information is presented on digital watermarking, broadband multimedia transmission, legal use of surveillance systems, performance evaluation criteria, and other new and emerging topics, along with applications for transports and pedestrian monitoring. The information contained in Multimedia Video-Based Surveillance Systems: Requirements, Issues and Solutions, bridges the distance between present practice and research findings, and the book is an indispensable reference tool for professional engineers
Area Throughput and Energy Efficiency for Clustered Wireless Sensor Networks Deployed in Bounded Regions
No full textIn this paper we present a mathematical approach to evaluate the area throughput and the energy consumption of a multi-sink Wireless Sensor Network (WSN). The WSN is organised into clusters, with one sink per cluster collecting data from sensors. A small variation of the Thomas point process is used to model sensors and sinks positions in the
target area. We denote as area throughput the amount of data per unit of time successfully transmitted to the
sinks. Both area throughput and energy consumption are strictly related to connectivity and MAC issues. The
aim of this work is to devise a mathematical model that takes MAC and connectivity issues into account, under a common
framework. We also explicitly include border effects induced by deployment into a finite region into our framework.
We study the behavior of these two performance metrics when varying the target rate, defined as the
maximum data rate the network was deployed to deliver. Results show that a tradeoff between the area
throughput and the energy consumption must be found, when considering two different scenarios, namely, a field and a
building
Multimedia Video-Based Surveillance Systems: from User Requirements to Research Solutions
No full textOpportunistic Networking for Sensor Data Collection in Urban Environment
No full textIn this paper we present the preliminary results from a work dealing with opportunistic networking in urban context. In particular we consider a set of sensors deployed in a city center, aimed at sampling e.g. environmental parameters. Such sensors then opportunistically exploit the urban vehicular mobility to transfer their measurements to one of data fusion centers, located at chosen points in the city. Both the sensor nodes and the vehicles are equipped with radio transceivers having a fixed transmission range and data storage capability (which is assumed to be limited). Here we present simulations based study conducted in the particular case of the city of Seattle, WA, since we had access to the actual mobility traces of the city bus fleet, collected by [1]. Some of the performance metrics that can be evaluated in our simulator environment are the delivery rate of packets originated from each sensor node,
the statistics of the transport delay and the fraction of packet drops due to limited storage buffer capability. We also highlight the role played by the number of sensors and fusion centers, and the effect of transmitting power. Possible extensions of this preliminary work include comparison to the results obtained when using (theoretical and measured) mobility traces
Area throughput and energy consumption for clustered wireless sensor networks
No full textIn this paper we present a mathematical approach to evaluate the area throughput and the energy consumption of a multi-sink Wireless Sensor Network (WSN). The WSN is organised into clusters, with one sink per cluster collecting data from sensors. A small variation of the Thomas point process is used to model sensors and sinks positions in the target area. We denote as area throughput the amount of samples per second successfully transmitted to the sinks. Both area throughput and energy consumption are strictly related to connectivity and MAC issues. The aim of this work is to devise a mathematical model that takes MAC and connectivity issues into account, under a common framework. We study the behavior of these two performance metrics when varying the target rate, defined as the maximum number of samples the network was deployed to deliver. Results show that a tradeoff between the area throughput and the energy consumption must be found. Finally, the impact of different sensors and sinks distributions on the area throughput is evaluated
Analysis of TCP parallelization over wireless links
No full textTCP parallelization uses a set of parallel TCP connections to transfer data for an application process. It can achieve a high throughput more quickly than a single connection and is less sensitive to transient/random packet losses or congestion. Along with other features, this makes the approach viable in lossy wireless networks, especially the emerging highspeed wireless networks where the top speed may never be reached by using a standard TCP connection. However, there is a lack of research efforts to explore the potential of TCP parallelization in wireless environments. In this paper, we present a general analysis of TCP parallelization in wireless environments without focusing on a specific wireless system. The analysis shows that TCP parallelization is capable of reducing the cost of losses on wireless links and can be a fundamental step towards improvement of the TCP performance in heterogeneous networks
Opportunities for white space usage in Australia
No full textWe discuss the scope and nature of opportunities for white space devices to operate in the UHF band in Australia after the digital dividend. We identify opportunities for white space usage in the reduced UHF band to be used for television services as well as in nearby guard bands. We extend the discussion to the longer-term by examining scenarios in which broadcasting services could use the synergistic effects of white space devices to either voluntarily migrate out of the UHF band or secure their occupation of this important spectrum beachhead
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