Search results for: W Heinzelman
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Emotion classification is essential for understanding human interactions and hence is a vital component of behavioral studies. Although numerous algorithms have been developed, the emotion classification accuracy is still short of what is desired for the algorithms to be used in real systems. In this paper, we evaluate an approach where basic acoustic features are extracted from speech samples, and...
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IEEE Transactions on Computers > 2011 > 60 > 5 > 707 - 722
In this paper, we present Multicasting through Time Reservation using Adaptive Control for Energy efficiency (MC--TRACE), an energy-efficient real-time data multicasting architecture for mobile ad hoc networks. MC-TRACE is a cross-layer design, where the medium access control layer functionality and the network layer functionality are performed by a single integrated layer. The basic design philosophy...
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Energy conservation is one of the primary goals of the majority of MAC protocols designed for wireless sensor networks. In Sensor-MAC (S-MAC), one of the first MAC protocols designed for sensor networks, nodes sleep and wake up periodically to save energy. MAC protocols such as Timeout-MAC (T-MAC) and Advertisement-MAC (ADV-MAC) improved upon S-MAC by introducing support for variable loads and providing...
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In this paper, we investigate the maximization of the amount of gathered data in a clustered wireless sensor network (WSN). The amount of gathered data is maximized by (1) choosing the optimal transmit power, and (2) selecting the optimal cluster head. For problem (1), we find closed-form solutions for the optimal or near optimal transmit power of cluster members (CM). For problem (2), we propose...
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Energy efficiency is one of the crucial design criteria for wireless sensor networks. Idle listening constitutes a major part of energy waste, and thus solutions such as duty cycling and the use of wake-up radios have been proposed to reduce idle listening and save energy. Compared to duty cycling, wake-up radios save more energy by reducing unnecessary wake-ups and collisions. In this paper, we investigate...
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IEEE Transactions on Wireless Communications > 2010 > 9 > 9 > 2800 - 2811
Impulse Radio Ultra WideBand (IR-UWB) communication has proven to be an important technique for supporting high-rate, short-range, and low-power communication. In this paper, using detailed models of typical IR-UWB transmitter and receiver structures, we model the energy consumption per information bit in a single link of an IR-UWB system, considering packet overhead, retransmissions, and a Nakagami-m...
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SMAC is a popular duty-cycled MAC protocol, designed for wireless sensor networks to save energy and prolong the network lifetime. However, existing work evaluates the performance of SMAC solely through simulations or field measurements. To the best of our knowledge, there are no analytical models for evaluating the performance of SMAC. In this paper, we propose a Markov model to describe the behavior...
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Several medium access control (MAC) protocols have been proposed for wireless sensor networks with the objective of minimizing energy consumption. For example, sensor-MAC (S-MAC) was proposed to reduce energy consumption by introducing a duty cycle. Under variable traffic load, the fixed duty cycle of S-MAC results in energy loss due to idle listening along with higher latency and lower throughput...
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We consider optimal resource allocation for wireless video sensors (WVSs), including the image sensor subsystem into the system analysis. By assigning a power-rate-distortion (P- R-D) characteristic for the image sensor, we build a comprehensive P-R-D framework for WVS optimization. Within the scope of the developed framework, we solve the problem of how to allocate power among the image sensor, compression,...
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Impulse radio ultra-wideband (IR-UWB) communication has proven an important technique for supporting high-rate, short-range, low-power communication. These are necessary criteria for emerging sensor networks, which oftentimes have very short distance communication requirements, necessitate low power operation and may require high data rates (e.g., for supporting the transmission of images or video)...
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In mobile ad hoc networks (MANETs), Quality of Service (QoS) of a multicast protocol is one of the most important performance metrics. Channel conditions and network topology frequently change, and in order to achieve a certain QoS, complex algorithms and protocols are needed. Often channel conditions are neglected during the design of a multicast protocol. However, vulnerability against channel errors...
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Soft clustering of the nodes combined with time division multiple access (TDMA) channel access within a cluster has been shown to provide an energy-efficient solution for mobile ad-hoc networks (MANET). Such channel access schemes use a parameter that is critical in determining network performance: the number of frames per superframe, which determines the amount of spatial reuse possible, similar...
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In this abstract, we present Advertisement MAC (ADVMAC), an advertisement based MAC protocol for wireless sensor networks. Simulation results show that ADV-MAC provides a better way to conserve energy and at the same time to support variable traffic loads.
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IEEE Transactions on Mobile Computing > 2009 > 8 > 5 > 709 - 720
Many sensor network applications require consistent coverage of the region in which they are deployed over the course of the network lifetime. However, because sensor networks may be deployed randomly, node distribution and data redundancy in some regions of the network may be lower than in others. The sensors in the sparsest regions should be considered more critical to the sensor network application...
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In this paper, we determine how to minimize energy consumption per information bit in a single link, with the consideration of packet retransmission and overhead. This is achieved by deriving expressions for the optimum target bit error probability and packet length at different transmission distances. Furthermore, the energy consumptions of different modulation schemes are compared over an additive...
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Quality of service (QoS) of a network-wide broadcast (NWB) protocol is one of the most important performance metrics, especially in mobile ad hoc networks, where channel conditions and network topology change frequently. We propose a mesh networking inspired approach to overcome the performance degradation caused by lossy channels. We show that our adaptive approach, whereby the amount of redundancy...
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IEEE Transactions on Image Processing > 2006 > 15 > 10 > 3053 - 3065
We propose a new adaptive filtering framework for local image registration, which compensates for the effect of local distortions/displacements without explicitly estimating a distortion/displacement field. To this effect, we formulate local image registration as a two-dimensional (2-D) system identification problem with spatially varying system parameters. We utilize a 2-D adaptive filtering framework...
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MILCOM 2005 - 2005 IEEE Military Communications Conference > 2642 - 2648 Vol. 4
In this paper, we present an analysis of the effects of channel noise on the performance of coordinated and non-coordinated MAC protocols. In order to observe the degradation in the performance of a coordinated MAC protocol (MH-TRACE) with increasing BER level, we created an analytical model to estimate MH-TRACE'S performance. This analytical model is validated through simulation experiments. Our...
