Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have significant impact on the overall energy dissipation of these networks. Based on our findings that the conventional protocols of direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster based station (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show the LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional outing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.

/pdf/energy-efficient-communication-protocol-for-wireless-4vhuagusz2.pdf

Energy-efficient communication protocol for wireless microsensor networks

Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have signicant impact on the overall energy dissipation of these networks. Based on our ndings that the conventional protocols of direct transmission, minimum-transmission-energy, multihop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster base stations (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show that LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional routing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.

Energy-efficient communication protocols for wireless microsensor networks

Determining optical flow

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

An automated method for segmenting magnetic resonance head images into brain and non-brain has been developed. It is very robust and accurate and has been tested on thousands of data sets from a wide variety of scanners and taken with a wide variety of MR sequences. The method, Brain Extraction Tool (BET), uses a deformable model that evolves to fit the brain's surface by the application of a set of locally adaptive model forces. The method is very fast and requires no preregistration or other pre-processing before being applied. We describe the new method and give examples of results and the results of extensive quantitative testing against "gold-standard" hand segmentations, and two other popular automated methods.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/hbm.10062

Fast robust automated brain extraction

Digital watermarking is the process of secretly embedding a short sequence of information containing owner identity or copyright information inside a digital signal, without changing its perceptual quality. The information is embedded in a way that is difficult to erase. We present a new oblivious digital watermarking method for copyright protection of still images. The technique is based on modifying the sign of a subset of low frequency, image transform coefficients with high to moderate magnitudes. These transforms include the DCT, DFT and Hadamard transforms. Watermark detection is done in an oblivious way. The robustness to a number of standard image processing attacks is demonstrated using the criteria of the latest StirMark benchmark test. The technique can be used also for other applications such as image fingerprinting.

Robust oblivious digital watermarking using image transform phase modulation

This paper presents a coordinated multiple-substream unequal error protection and error concealment algorithm for SPIHT-coded bitstreams transmitted over lossy channels. In the proposed scheme, we divide the video sequence corresponding to a group of pictures into two sub-sequences in the temporal domain and independently encode each sub-sequence with a 3-D SPIHT algorithm to generate two independent substreams. Each substream is protected by an FEC-based unequal error protection algorithm that assigns unequal forward error correction codes for each substream with bit-plane granularity. The information that is lost during transmission for one substream is estimated at the receiver by using the correlation between the two substreams and the smoothness of the video signal. Simulation results show that the proposed multiple-substream UEP algorithm is simple, fast, and robust in hostile network conditions, and that the proposed error concealment algorithm achieves about 1-3 dB PSNR gain over the case where there is no error concealment at high packet loss rates.

An integrated multiple-substream unequal error protection and error concealment algorithm for Internet video applications

Resolution enhancement for video sequences has always been an attractive application in multimedia signal processing. "Superresolution" methods, that combine non-redundant information from a set of low-resolution images, are beginning to be applied to the most popular video compression standard, MPEG. Bayesian approaches, which are very successful for raw video, largely fail for MPEG video, since they do not incorporate the compression process into their models. This compression process introduces quantization noise, which is comparable to the additive noise that is used in the Bayesian models. We present an analytical derivation that combines the quantization and additive noises in a stochastic framework for MPEG-compressed video. This is a general framework in the sense that different video acquisition models, source statistics, implementation techniques can be used with it.

Bayesian resolution-enhancement framework for transform-coded video

New approaches to block filtering of images are presented based on the recently introduced operation of symmetric convolution. Symmetric convolution is a formalized approach to convolving symmetric finite impulse response (FIR) filters with symmetrically extended data. It is efficient because the discrete sine and cosine transforms (DST & DCT) can be used to perform the convolution as a transform-domain multiplication. With proper zero-padding of the input data, symmetric convolution gives the same result as linear convolution. As a consequence, it is now possible to use the overlap-add and overlap-save techniques with DSTs and DCTs in order to efficiently filter large images. An alternative method to conventional block filtering is proposed, whereby the blocks need not be overlapped. This approach is extended for those applications where reduced complexity is needed and the approximation to conventional linear filtering is adequate. >

New approaches to block filtering of images using symmetric convolution and the DST or DCT

Multiple description coding addresses the problem of encoding a source signal into two or more sub-streams. Each sub-stream is assumed to be transmitted over an independent path. However, multiple independent paths may not be available, and for most cases only a single path can be used. The scheduling of these descriptions over a single path is still problematic because of the bursty packet loss behavior. In this paper, we propose a novel packet scheduling method for multiple description coded video transmission over a single path. The proposed method adaptively schedules the descriptions according to channel conditions by jointly considering the bursty packet loss behavior and the transmission delay of the network. The simulation results show that the proposed method can improve the video quality by 1.5 dB on average as compared to the method of sending one packet of each description right after the other. It also outperforms a heuristic interleaving approach by roughly 0.3-0.45 dB, depending on the channel conditions.

Russell M. Mersereau

Papers

Robust oblivious digital watermarking using image transform phase modulation

An integrated multiple-substream unequal error protection and error concealment algorithm for Internet video applications

Bayesian resolution-enhancement framework for transform-coded video

New approaches to block filtering of images using symmetric convolution and the DST or DCT

Optimal packet scheduling for multiple description coded video transmissions over lossy networks