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Brain image segmentation is one of the most important applications in medicine and also is one of the most challenging topics in the field of medical image processing. In general, most automatic segmentation methods consist of an energy function, a shape model, and an optimization strategy. Each plays an important role in the design of an accurate segmentation algorithm. Here we introduce a modified...
In this paper, we consider a slow-fading nt ×nr multiple-input multiple-output (MIMO) channel subjected to block fading. Reliability (in terms of achieved diversity order) and rate (in number of symbols transmitted per channel use) are of interest in such channels. We propose a new precoding scheme which achieves both full diversity (nt ×nrth order diversity) as well as full rate (nt symbols per channel...
Switch-and-stay combining (SSC) is a low-complexity alternative of selection combining in diversity schemes with two receiving antennas. Its operation is based upon activating a single diversity branch and maintaining it active for as long as the corresponding channel is sufficiently strong, regardless of the quality of the remaining branch. In this respect, we optimize here the switching threshold...
In this paper, we present a new non-data-aided (NDA) maximum likelihood (ML) time delay estimator based on importance sampling (IS). We show that a grid search and lack of convergence from which most iterative estimators suffer can be avoided. It is assumed that the transmitted data are completely unknown at the receiver. Moreover the carrier phase is considered as an unknown nuisance parameter. The...
We present DELTR, an automated pipeline for the analysis of time-resolved light sheet fluorescence microscopy images of zebrafish embryogenesis. It comprises 3D nucleus segmentation using shape-regularized graph cuts, parallelized extraction of geometrical features, and cell tracking by means of combinatorial optimization. We also discuss the interactive visualization software used for validating...
Filamentary structures extraction in medical and biological images is a challenging problem. Muscular/Neural fibers, neurites and blood arteries are some examples. Their delineation is particularly problematic due to the lack of solid visual support that is also compromised by the presence of clutter and low signal to noise ratios. In this article, we propose a modular approach to curvilinear structures...
Cognitive Radio (CR) improves spectral efficiency by allowing unlicensed (secondary) users to concurrently operate with licensed (primary) users. The side-lobe interference from an OFDM-based secondary user (SU) causes unwanted interference to the primary user (PU) of the spectrum. While interference mitigation to the PU spectral band has received a lot of attention in recent literature, the novelty...
Vehicular Ad hoc Networks (VANETs) are a special type of Mobile Ad hoc Networks (MANETs), made by vehicles communicating among themselves, and by vehicles communicating to devices located in the margins of roads and highways. The main characteristic of a VANET is the high speed of network nodes - that can go up to 200 km/h -, and that impacts directly on the ability the network has to deliver data,...
Optimization of hard fusion spectrum sensing using the k-out-of-N rule is considered. Two different setups are used to derive the optimal k. A throughput optimization setup is defined by minimizing the probability of false alarm subject to a probability of detection constraint representing the interference of a cognitive radio with the primary user, and an interference management setup is considered...
The EDA design flows must be retooled to cope with the rapid increase in the number of operational modes and process corners for a VLSI circuit, which in turn results in different and sometimes conflicting design goals and requirements. Single-objective solutions to various design optimization problems, ranging from sizing and fanout optimization to technology mapping and cell placement, must hence...
Radio frequency spectrum in wireless communication is a common resource shared by all collocated devices. Most spectrum management schemes rely on a centralized base station-receiver station relaying architecture. In contrast, infrastructure-less systems including wireless ad hoc networks require a scalable, distributed methodology. Moreover, the access has to be coordinated among the nodes in the...
This paper addresses the problem of integration testing of data-centric dynamic compositions in service-based systems. These compositions define abstract services, which are replaced by invocations to concrete candidate services at runtime. Testing all possible runtime instances of a composition is often unfeasible. We regard data dependencies between services as potential points of failure, and introduce...
The ultimate success of the Wireless Mesh Network paradigm (WMN) in large scale deployments depends on the ability to test it in real world scenarios. A typical application scenario which is worth to be investigated in such a context is peer-to-peer traffic management. The creation of large scale testbeds for evaluating wireless mesh technologies and protocols, and for testing their ability to support...
In medical imaging, there are many approaches for automatic segmentation. However, none of these methods provide any effective solution to correct segmentation interactively, which becomes a necessity in the case of poorly defined structures. Manual segmentation can not be an alternative given that it might be unfeasible in many cases. On the other hand, how to complete a poor automatic segmentation...
1TCP is a popular transport layer protocol. The performance of TCP is known to be unsatisfactory in wireless network, due to high bit error rates or drop outs. Employing error correction at the transport layer can alleviate the problem to some extent. We make three contributions in this paper. First, we optimize the efficiency of repetitive codes. In particular, we propose a good estimate on throughput...
We develop a new algorithm to segment the hippocampus from MR images. Our method uses a new classifier ensemble algorithm to correct segmentation errors produced by a multi-atlas based segmentation method. Our classifier ensemble algorithm searches for the maximum likelihood solution via gradient ascent optimization. Compared to the additive regression based algorithm, LogitBoost, our algorithm avoids...
Investigating multi-feature information-theoretic image registration, we introduce consistent and asymptotically unbiased kth-nearest neighbor (kNN) estimators of mutual information (MI), normalized MI and exclusive information applicable to high-dimensional random variables, and derive under closed-form their gradient flows over finite- and infinite-dimensional transform spaces. Using these results,...
The problem of reconstruction of ultrasound images by means of blind deconvolution has long been recognized as one of the central problems in medical ultrasound imaging. In this paper, a hybrid deconvolution method is employed to recover a reliable estimate of the tissue reflectivity function directly from ultrasound RF data. Here, the “hybridization” suggests a two-stage reconstruction scheme, in...
We have developed a hybrid system for imaging small animals using fluorescence optical tomography (FOT) and positron emission tomography (PET) simultaneously. This paper presents a statistical method for reconstructing spatial distribution of dual-labeled tracers from the combined PET and FOT data. We use the Poisson likelihood function for the PET data and Gaussian distribution for the FOT data....
In this paper, we propose a hexagonal microstrip dual - mode band pass filter by optimizing various geometrical parameters associated with the filter geometry using IE3D full-wave simulation software. The response of the optimized filter is studied and analyzed and the results have been reported. Work also explores the possibility of changing the type of the filter response from Elliptical to Chebyshev...
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