MSCS Faculty Research and PublicationsCopyright (c) 2014 Marquette University All rights reserved.
http://epublications.marquette.edu/mscs_fac
Recent documents in MSCS Faculty Research and Publicationsen-usFri, 25 Jul 2014 01:56:20 PDT3600H-Enrichments and Their Homeomorphism Groups
http://epublications.marquette.edu/mscs_fac/195
http://epublications.marquette.edu/mscs_fac/195Wed, 23 Jul 2014 13:56:44 PDTPaul BankstoniPrevention: Towards a Novel Real-Time Smartphone-Based Fall Prevention System
http://epublications.marquette.edu/mscs_fac/194
http://epublications.marquette.edu/mscs_fac/194Thu, 17 Jul 2014 12:52:12 PDT
Falling remains one of the leading causes of hospitalization and death for the elderly all around the world. The considerable risk of falls and the substantial increase of the elderly population have stimulated scientific research on smartphone-based fall detection systems recently. Even though these systems are helpful for fall detection, the best way to reduce the number of falls and their consequences is to prevent them from happening in the first place. Therefore, our focus is on fall prevention rather than fall detection. To address the issue of fall prevention, in this paper, we propose a smartphone-based fall prevention system that can alert the user about their abnormal walking pattern. Most current systems merely detect a fall whereas our approach attempts to identify high-risk gait patterns and alert the user to save them from an imminent fall. Our system uses a gait analysis approach that couples cycle detection with feature extraction to detect gait abnormality. We validated our approach using a decision tree with 10-fold cross validation and found 99.8% accuracy in gait abnormality detection. To the best of our knowledge, we are the first to use the built-in accelerometer and gyroscope of the smartphone to identify abnormal gaits in users for fall prevention.
]]>
AKM Jahangir Alam Majumder et al.On the Distributions of Certain Spacings
http://epublications.marquette.edu/mscs_fac/193
http://epublications.marquette.edu/mscs_fac/193Mon, 14 Jul 2014 09:57:49 PDT
A characterization of the uniform distribution based on distributions of spacings is presented which extends the existing result in this direction. Also, a result on the distribution of spacings for distributions close to the uniform one is discussed.
]]>
Gholamhossein Hamedani et al.Conditional Moments, Sub-Independence and Independence II
http://epublications.marquette.edu/mscs_fac/192
http://epublications.marquette.edu/mscs_fac/192Mon, 14 Jul 2014 09:48:09 PDT
We recall a concept called sub-independence, which is defined in terms of the convolution of the distributions of random variables, providing a stronger sense of dissociation between random variables than that of uncorrelatedness. In risk and decision analysis, the investigator may encounter a stochastic model whose components are uncorrelated dependent random variables. The marginal distributions of the components are known but not their joint distribution. The investigator, however, is interested in (or in need of) the distribution of the sum of some or all of the components. The concept of sub-independence will allow the determination of the distribution of the sum of the components based on the marginal distributions of the summands. This concept is much weaker than that of independence and yet can be employed to determine the distribution of the sum of random variables from their marginal distributions. We shall mention some possible applications of the concept of sub-independence to risk and decision analysis.
]]>
Gholamhossein Hamedani et al.Characterizations of Continuous Univariate Distributions Based on the Truncated Moments of Functions of Order Statistics
http://epublications.marquette.edu/mscs_fac/191
http://epublications.marquette.edu/mscs_fac/191Mon, 14 Jul 2014 09:31:07 PDT
Most of the well-known continuous univariate distributions are characterized based on a truncated moment of a function of the 1^{st} order statistic or of the n^{th} order statistic.
]]>
Gholamhossein HamedaniCharacterizations of Distributions of Ratio of Rayleigh Random Variables
http://epublications.marquette.edu/mscs_fac/190
http://epublications.marquette.edu/mscs_fac/190Fri, 11 Jul 2014 11:13:17 PDT
Various characterizations of the distribution of the ratio of two independent Rayleigh random variables are presented. These characterizations are based, on a truncated moment; on hazard function; and on certain functions of order statistics.
]]>
Gholamhossein HamedaniMicro-Environment Causes Reversible Changes in DNA Methylation and mRNA Expression Profiles in Patient-Derived Glioma Stem Cells
http://epublications.marquette.edu/mscs_fac/189
http://epublications.marquette.edu/mscs_fac/189Mon, 07 Jul 2014 09:52:28 PDTIn vitro and in vivo models are widely used in cancer research. Characterizing the similarities and differences between a patient's tumor and corresponding in vitro and in vivo models is important for understanding the potential clinical relevance of experimental data generated with these models. Towards this aim, we analyzed the genomic aberrations, DNA methylation and transcriptome profiles of five parental tumors and their matched in vitro isolated glioma stem cell (GSC) lines and xenografts generated from these same GSCs using high-resolution platforms. We observed that the methylation and transcriptome profiles of in vitro GSCs were significantly different from their corresponding xenografts, which were actually more similar to their original parental tumors. This points to the potentially critical role of the brain microenvironment in influencing methylation and transcriptional patterns of GSCs. Consistent with this possibility, ex vivo cultured GSCs isolated from xenografts showed a tendency to return to their initial in vitro states even after a short time in culture, supporting a rapid dynamic adaptation to the in vitro microenvironment. These results show that methylation and transcriptome profiles are highly dependent on the microenvironment and growth in orthotopic sites partially reverse the changes caused by in vitro culturing.
]]>
Mehmet Baysan et al.When Hausdorff Continua Have No Gaps
http://epublications.marquette.edu/mscs_fac/188
http://epublications.marquette.edu/mscs_fac/188Thu, 26 Jun 2014 13:51:21 PDT
An interpretation of betweenness on a set is gap free if each two distinct points of the set have a third point between them. In this paper we are interested in gap free betweenness relations naturally induced by the topology of Hausdorff continua. In particular, we say c lies between a and b in the K-interpretation precisely when every subcontinuum that contains both a and b also contains c. We explore the connection between K-gap freeness and hereditary unicoherence.
]]>
Paul BankstonTopological Reduced Products and the GCH
http://epublications.marquette.edu/mscs_fac/187
http://epublications.marquette.edu/mscs_fac/187Thu, 26 Jun 2014 13:42:10 PDT
Since its inception in the late fifties, the theory of reduced products in model theory and algebra has developed into an active field of research with increasingly many participants. In particular the theory of ultraproducts has provided "algebraic" proofs of the compactness theorem of first order logic, the existence of saturated models of certain kinds; as well as a characterization of the notion of elementary equivalence between models. Copious details can be found in [BS] and [CK]. In our paper [B] we attempted to translate the notion of reduced product into the context of general topology and found, not too surprisingly, that here was a vast untapped source of research problems, many of the type already encountered in the theory of box products. In [B] several parallel problems involving box products and "topological" ultraproducts are explored; and it turns out that the ultraproduct theorems are often either easier than their counterparts to prove or can be proved directly in ZFC without recourse to extra set-theoretic axioms. Topological reduced products are formed as certain quotients of box products where the equivalence relations in question derive from filters on the index set. In this note ~N'e present a result about paracompactness in topological ultraproducts (i.e. where the filter is maximal) and show how this result relates to a known theorem about paracompactness in box products (trivially reduced products via the singleton filter). Both of these results relate directly with the Generalized Continuum Hypothesis (GCH).
]]>
Paul BankstonTopological Measures of Systems of Sets
http://epublications.marquette.edu/mscs_fac/186
http://epublications.marquette.edu/mscs_fac/186Wed, 25 Jun 2014 09:15:34 PDT
If X is an infinite set, we may topologize the power set of X naturally so that systems of subsets of X can be described in the language of Baire category. Systems we consider include: subalgebra lattices of algebraic structures; topologies; filters; and families of almost disjoint sets.
]]>
Paul BankstonContinua and the Co-elementary Hierarchy of Maps
http://epublications.marquette.edu/mscs_fac/185
http://epublications.marquette.edu/mscs_fac/185Wed, 25 Jun 2014 08:52:41 PDT
The co-elementary hierarchy is a nested ordinal-indexed sequence of classes of mappings between compacta, with each successor level being defined inductively from the previous one using the topological ultracopower construction. The lowest level is the class of continuous surjections; and the next level up, the coexistential maps, is already a much more restricted class. Co-existential maps are weakly confluent, and monotone when their images are locally connected. These maps also preserve important topological properties, such as: being infinite, being of covering dimensions ≤ n, and being a (hereditarily decomposable, indecomposable, hereditarily indecomposable) continuum.
]]>
Paul BankstonCharacterizations of Certain Continuous Univariate Distributions Based on the Conditional Distribution of Generalized Order Statistics
http://epublications.marquette.edu/mscs_fac/184
http://epublications.marquette.edu/mscs_fac/184Tue, 24 Jun 2014 14:45:44 PDT
The problem of characterizing probability distributions is an interesting problem which has recently attracted the attention of many researchers. Various characterization results have been established in different directions as reported in the literature. We present here, various characterizations of certain univariate continuous distributions based on the conditional distribution of generalized order statistics.
]]>
M. Ahsanullaha et al.Feature Extraction Method for Real Time Human Activity Recognition on Cell Phones
http://epublications.marquette.edu/mscs_fac/183
http://epublications.marquette.edu/mscs_fac/183Mon, 19 May 2014 08:30:20 PDT
In this paper we contribute a novel linear-time method for extracting features from acceleration sensor signals in order to identify human activities. We benchmark this method using a standard acceleration-based activity recognition dataset called SCUT-NAA. The results show that the described method performs best when the training and testing data are from the same person. In this context, a linear kernel based support vector machine (SVM) classifier and a radial basis function (RBF) based one produced similar levels of accuracy. Finally we demonstrate an application of the proposed method for realtime activity recognition on a cell phone with a single triaxial accelerometer. This feature extraction method can be used for realtime activity recognition on resource constrained devices.
]]>
Mridul Khan et al.Toward Collective Intelligence for Fighting Obesity
http://epublications.marquette.edu/mscs_fac/182
http://epublications.marquette.edu/mscs_fac/182Mon, 12 May 2014 09:54:27 PDT
The emergent prevalence of childhood and adolescent obesity remains one of the most significant health care challenges facing the United States today. On the other hand, breakthroughs in Human-Robot Interaction (HRI) research and the diminishing cost of personal robots and virtual agents along with the ever-increasing use of smart personal devices, suggests that there is room for harnessing the power of ubiquitous intelligent systems that can work in partnership to solve some of our most difficult challenges in the very near future. In this paper, we present the design and prototype implementation of a collective intelligence approach aimed at employing machine learning algorithms that work in concert to facilitate the personalization of a humanoid robot Health Coach with a focus on childhood obesity intervention through Child-Robot Interactions and other adaptive Ubiquitous Computing (UbiComp) solutions.
]]>
Ivor D. Addo et al.RSSI Based Indoor Localization for Smartphone Using Fixed and Mobile Wireless Node
http://epublications.marquette.edu/mscs_fac/181
http://epublications.marquette.edu/mscs_fac/181Mon, 12 May 2014 09:38:46 PDT
Nowadays with the dispersion of wireless networks, smartphones and diverse related services, different localization techniques have been developed. Global Positioning System (GPS) has a high rate of accuracy for outdoor localization but the signal is not available inside of buildings. Also other existing methods for indoor localization have low accuracy. In addition, they use fixed infrastructure support. In this paper, we present a novel system for indoor localization, which also works well outside. We have developed a mathematical model for estimating location (distance and direction) of a mobile device using wireless technology. Our experimental results on Smartphones (Android and iOS) show good accuracy (an error less than 2.5 meters). We have also used our developed system in asset tracking and complex activity recognition.
]]>
Md O. Gani et al.Effects of Dynamic Voltage and Frequency Scaling on a K20 GPU
http://epublications.marquette.edu/mscs_fac/180
http://epublications.marquette.edu/mscs_fac/180Mon, 12 May 2014 08:44:59 PDT
Improving energy efficiency is an ongoing challenge in HPC because of the ever-increasing need for performance coupled with power and economic constraints. Though GPU-accelerated heterogeneous computing systems are capable of delivering impressive performance, it is necessary to explore all available power-aware technologies to meet the inevitable energy efficiency challenge. In this paper, we experimentally study the impacts of DVFS on application performance and energy efficiency for GPU computing and compare them with those of DVFS for CPU computing. Based on a power-aware heterogeneous system that includes dual Intel Sandy Bridge CPUs and the latest Nvidia K20c Kepler GPU, the study provides numerous new insights, general trends and exceptions of DVFS for GPU computing. In general, the effects of DVFS on a GPU differ from those of DVFS on a CPU. For example, on a GPU running compute-bound high-performance and high-throughput workloads, the system performance and the power consumption are approximately proportional to the GPU frequency. Hence, with a permissible power limit, increasing the GPU frequency leads to better performance without incurring a noticeable increase in energy. This paper further provides detailed analytical explanations of the causes of the observed trends and exceptions. The findings presented in this paper have the potential to impact future CPU and GPU architectures to achieve better energy efficiency and point out directions for designing effective DVFS schedulers for heterogeneous systems.
]]>
Rong Ge et al.Improving Performance and Energy Efficiency of Matrix Multiplication via Pipeline Broadcast
http://epublications.marquette.edu/mscs_fac/179
http://epublications.marquette.edu/mscs_fac/179Mon, 12 May 2014 08:34:06 PDT
Boosting performance and energy efficiency of scientific applications running on high performance computing systems arise cruicially nowadays. Software and hardware based solutions for improving communication performance have been recognized as significant means of achieving performance gain and thus energy savings for such applications. As a fundamental component of most numerical linear algebra algorithms, improving performance and energy efficiency of distributed matrix multiplication is of major concerns. For such purposes, we propose a high performance communication scheme that fully exploits network bandwidth via non-blocking pipeline broadcast with tuned chunk size. Empirically, substantial performance gain up to 8.4% and energy savings up to 6.9% are achieved compared to blocking pipeline broadcast, and against binomial tree broadcast, performance gain up to 6.5% and energy savings up to 6.1% are observed on a 64-core cluster.
]]>
Li Tan et al.Energy-Efficient Scheduling for Multicore Systems with Bounded Resources
http://epublications.marquette.edu/mscs_fac/178
http://epublications.marquette.edu/mscs_fac/178Mon, 12 May 2014 08:22:28 PDT
High energy cost has become a salient constraint of the next generation of multicore based supercomputers. One approach that has the potential to conserve energy is to reduce the number of resources allocated for a given parallel application. However, this approach raises the concern that utilizing bounded resources may adversely affect performance. In this paper, we demonstrate that utilizing bounded resources to execute parallel tasks with dependency on multicore systems can actually conserve energy without degrading performance. We achieve this goal by proposing BREES, an energy-efficient scheduling algorithm for multicore systems with bounded resources. The proposed BREES algorithm takes advantage of the Dynamic Voltage Scaling (DVS) algorithm and the task duplication strategy. In addition, a dynamic waiting window (DWW) is implemented in BREES to handle the system hardware heterogeneity. We evaluate the effectiveness of BREES by conducting a series of experiments using both real world and synthetically generated parallel applications on fifteen different multicore processors and four well-known high speed networks.
]]>
Ziliang Zong et al.Power and Energy Characteristics of MapReduce Data Movements
http://epublications.marquette.edu/mscs_fac/177
http://epublications.marquette.edu/mscs_fac/177Mon, 12 May 2014 08:12:06 PDT
Worldwide data centers consume about 300 billion kWh of energy per year, which accounts for 2% of total electricity use. As MapReduce becomes the mainstream paradigm for data-intensive computing in data centers, optimizing MapReduce energy efficiency can greatly mitigate energy requirements and reduce energy bills. Numerous studies have attempted to improve MapReduce energy efficiency, but few have approached this problem from understanding and reducing the energy impact of data movements. As data movements are often performance and energy bottlenecks, we propose a data movement centric approach and present an analysis framework with methods and metrics for evaluating costly built-in MapReduce data movements. Our experimental investigation leverages the fine-grained performance and power profiling framework eTune and reveals unique system-level and component-level energy characteristics of data movements. It also shows the scalability of energy efficiency with MapReduce workload and system parameters. These energy characteristics can be exploited in system design and resource allocation to improve data-intensive computing energy efficiency.
]]>
Thomas Wirtz et al.Counting Independent Sets of a Fixed Size in Graphs with Given Minimum Degree
http://epublications.marquette.edu/mscs_fac/176
http://epublications.marquette.edu/mscs_fac/176Tue, 22 Apr 2014 14:26:37 PDT
Galvin showed that for all fixed δ and sufficiently large n, the n-vertex graph with minimum degree δ that admits the most independent sets is the complete bipartite graph . He conjectured that except perhaps for some small values of t, the same graph yields the maximum count of independent sets of size t for each possible t. Evidence for this conjecture was recently provided by Alexander, Cutler, and Mink, who showed that for all triples with , no n-vertex bipartite graph with minimum degree δ admits more independent sets of size t than . Here, we make further progress. We show that for all triples with and , no n-vertex graph with minimum degree δ admits more independent sets of size t than , and we obtain the same conclusion for and . Our proofs lead us naturally to the study of an interesting family of critical graphs, namely those of minimum degree δ whose minimum degree drops on deletion of an edge or a vertex.
]]>
John Engbers et al.