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Full-Text Articles in Physical Sciences and Mathematics

Hierarchical Fusion Based Deep Learning Framework For Lung Nodule Classification, Kazim Sekeroglu Oct 2017

Hierarchical Fusion Based Deep Learning Framework For Lung Nodule Classification, Kazim Sekeroglu

LSU Doctoral Dissertations

Lung cancer is the leading cancer type that causes the mortality in both men and women. Computer aided detection (CAD) and diagnosis systems can play a very important role for helping the physicians in cancer treatments. This dissertation proposes a CAD framework that utilizes a hierarchical fusion based deep learning model for detection of nodules from the stacks of 2D images. In the proposed hierarchical approach, a decision is made at each level individually employing the decisions from the previous level. Further, individual decisions are computed for several perspectives of a volume of interest (VOI). This study explores three different …


Information Theoretic Study Of Gaussian Graphical Models And Their Applications, Ali Moharrer Aug 2017

Information Theoretic Study Of Gaussian Graphical Models And Their Applications, Ali Moharrer

LSU Doctoral Dissertations

In many problems we are dealing with characterizing a behavior of a complex stochastic system or its response to a set of particular inputs. Such problems span over several topics such as machine learning, complex networks, e.g., social or communication networks; biology, etc. Probabilistic graphical models (PGMs) are powerful tools that offer a compact modeling of complex systems. They are designed to capture the random behavior, i.e., the joint distribution of the system to the best possible accuracy. Our goal is to study certain algebraic and topological properties of a special class of graphical models, known as Gaussian graphs. First, …


Succinct Data Structures For Parameterized Pattern Matching And Related Problems, Arnab Ganguly Jan 2017

Succinct Data Structures For Parameterized Pattern Matching And Related Problems, Arnab Ganguly

LSU Doctoral Dissertations

Let T be a fixed text-string of length n and P be a varying pattern-string of length |P| <= n. Both T and P contain characters from a totally ordered alphabet Sigma of size sigma <= n. Suffix tree is the ubiquitous data structure for answering a pattern matching query: report all the positions i in T such that T[i + k - 1] = P[k], 1 <= k <= |P|. Compressed data structures support pattern matching queries, using much lesser space than the suffix tree, mainly by relying on a crucial property of the leaves in the tree. Unfortunately, in many suffix tree variants (such as parameterized suffix tree, order-preserving suffix tree, and 2-dimensional suffix tree), this property does not hold. Consequently, compressed representations of these suffix tree variants have been elusive. We present the first compressed data structures for two important variants of the pattern matching problem: (1) Parameterized Matching -- report a position i in T if T[i + k - 1] = f(P[k]), 1 <= k <= |P|, for a one-to-one function f that renames the characters in P to the characters in T[i,i+|P|-1], and (2) Order-preserving Matching -- report a position i in T if T[i + j - 1] and T[i + k -1] have the same relative order as that of P[j] and P[k], 1 <= j < k <= |P|. For each of these two problems, the existing suffix tree variant requires O(n*log n) bits of space and answers a query in O(|P|*log sigma + occ) time, where occ is the number of starting positions where a match exists. We present data structures that require O(n*log sigma) bits of space and answer a query in O((|P|+occ) poly(log n)) time. As a byproduct, we obtain compressed data structures for a few other variants, as well as introduce two new techniques (of independent interest) for designing compressed data structures for pattern matching.


Empirically Tuning Hpc Kernels With Ifko, Md Majedul Haque Sujon Jan 2017

Empirically Tuning Hpc Kernels With Ifko, Md Majedul Haque Sujon

LSU Doctoral Dissertations

iFKO (iterative Floating point Kernel Optimizer) is an open-source iterative empirical compilation framework which can be used to tune high performance computing (HPC) kernels. The goal of our research is to advance iterative empirical compilation to the degree that the performance it can achieve is comparable to that delivered by painstaking hand tuning in assembly. This will allow many HPC researchers to spend precious development time on higher level aspects of tuning such as parallelization, as well as enabling computational scientists to develop new algorithms that demand new high performance kernels. At present, algorithms that cannot use hand-tuned performance libraries …


Decentralized Scheduling For Many-Task Applications In The Hybrid Cloud, Brian Lyle Peterson Jan 2017

Decentralized Scheduling For Many-Task Applications In The Hybrid Cloud, Brian Lyle Peterson

LSU Doctoral Dissertations

While Cloud Computing has transformed how we solve many computing tasks, some scientific and many-task applications are not efficiently executed on cloud resources. Decentralized scheduling, as studied in grid computing, can provide a scalable system to organize cloud resources and schedule a variety of work. By measuring simulations of two algorithms, the fully decentralized Organic Grid, and the partially decentralized Air Traffic Controller from IBM, we establish that decentralization is a workable approach, and that there are bottlenecks that can impact partially centralized algorithms. Through measurements in the cloud, we verify that our simulation approach is sound, and assess the …


Maintaining High Performance Across All Problem Sizes And Parallel Scales Using Microkernel-Based Linear Algebra, Md Rakib Hasan Jan 2017

Maintaining High Performance Across All Problem Sizes And Parallel Scales Using Microkernel-Based Linear Algebra, Md Rakib Hasan

LSU Doctoral Dissertations

Linear algebra underlies a large proportion of computational problems. With the continuous increase of scale on modern hardware, performance of small sized linear algebra has become increasingly important. To overcome the shortcomings of conventional approaches, we employ a new approach using a microkernel framework provided by ATLAS to improve the performance of a few linear algebra routines for all problem sizes. Our initial research consists of improving the performance of parallel LU factorization in ATLAS for which we were able to achieve up to 2.07x and 2.66x speedup for small problems, up to 91% and 87% of theoretical peak performance …


Symbolic And Deep Learning Based Data Representation Methods For Activity Recognition And Image Understanding At Pixel Level, Manohar Karki Jan 2017

Symbolic And Deep Learning Based Data Representation Methods For Activity Recognition And Image Understanding At Pixel Level, Manohar Karki

LSU Doctoral Dissertations

Efficient representation of large amount of data particularly images and video helps in the analysis, processing and overall understanding of the data. In this work, we present two frameworks that encapsulate the information present in such data. At first, we present an automated symbolic framework to recognize particular activities in real time from videos. The framework uses regular expressions for symbolically representing (possibly infinite) sets of motion characteristics obtained from a video. It is a uniform framework that handles trajectory-based and periodic articulated activities and provides polynomial time graph algorithms for fast recognition. The regular expressions representing motion characteristics can …