Filter optimization and complexity reduction for video coding using graph-based transforms

The basis functions of lifting transform on graphs are completely determined by finding a bipartition of the graph and defining the prediction and update filters to be used. In this work we consider the design of prediction filters that minimize the quadratic prediction error and therefore the energy of the detail coefficients, which will give rise to higher energy compaction. Then, to determine the graph bipartition, we propose a distributed maximum-cut algorithm that significantly reduces the computational cost with respect to the centralized version used in our previous work. The proposed techniques show improvements in coding performance and computational cost as compared to our previous work.This work was supported in part by NSF under grant CCF-1018977Publicad

Automatic Placement of Outer Volume Suppression Slices in MR Spectroscopic Imaging of the Human Brain

Spatial suppression of peripheral regions (outer volume suppression) is used in MR spectroscopic imaging to reduce contamination from strong lipid and water signals. The manual placement of outer volume suppression slices requires significant operator interaction, which is time consuming and introduces variability in volume coverage. Placing a large number of outer volume saturation bands for volumetric MR spectroscopic imaging studies is particularly challenging and time consuming and becomes unmanageable as the number of suppression bands increases. In this study, a method is presented that automatically segments a high-resolution MR image in order to identify the peripheral lipid-containing regions. This method computes an optimized placement of suppression bands in three dimensions and is based on the maximization of a criterion function. This criterion function maximizes coverage of peripheral lipid-containing areas and minimizes suppression of cortical brain regions and regions outside of the head. Computer simulation demonstrates automatic placement of 16 suppression slices to form a convex hull that covers peripheral lipid-containing regions above the base of the brain. In vivo metabolite mapping obtained with short echo time proton-echo-planar spectroscopic imaging shows that the automatic method yields a placement of suppression slices that is very similar to that of a skilled human operator in terms of lipid suppression and usable brain voxels.Publicad

Filter optimization and complexity reduction for video coding using graph-based transforms

The basis functions of lifting transform on graphs are completely determined by finding a bipartition of the graph and defining the prediction and update filters to be used. In this work we consider the design of prediction filters that minimize the quadratic prediction error and therefore the energy of the detail coefficients, which will give rise to higher energy compaction. Then, to determine the graph bipartition, we propose a distributed maximum-cut algorithm that significantly reduces the computational cost with respect to the centralized version used in our previous work. The proposed techniques show improvements in coding performance and computational cost as compared to our previous work.This work was supported in part by NSF under grant CCF-1018977Publicad

EXCHANGING USER PROFILES TO CONNECT PEERS IN DISTRIBUTED SYSTEMS

Abstract – In this paper we introduce a user profile exchange mechanism, called barter or trading without money, that does not make use of countable resources in a dynamic information retrieval environment. We consider a network of inter-connected users, who behave both as information consumers and producers, within a multi-agent system which operates in a peer-topeer fashion. Our aim is to get a fast and efficient information resource management (maximum profit) using a network topology as simple as possible (minimum cost), for a given set of user restrictions (limited memory and period of waiting)