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Articles 3241 - 3270 of 16838

Full-Text Articles in Physical Sciences and Mathematics

Wireless And Sensor Networks Security (Wsns): A Retrospection, Falko Dressler, Yong Guan, Zhen Jiang Jun 2017

Wireless And Sensor Networks Security (Wsns): A Retrospection, Falko Dressler, Yong Guan, Zhen Jiang

Yong Guan

No abstract provided.


Interdependence Of Inhibitor Recognition In Hiv-1 Protease, Janet L. Paulsen, Florian Leidner, Debra A. Ragland, Nese Kurt Yilmaz, Celia A. Schiffer Jun 2017

Interdependence Of Inhibitor Recognition In Hiv-1 Protease, Janet L. Paulsen, Florian Leidner, Debra A. Ragland, Nese Kurt Yilmaz, Celia A. Schiffer

Celia A. Schiffer

Molecular recognition is a highly interdependent process. Subsite couplings within the active site of proteases are most often revealed through conditional amino acid preferences in substrate recognition. However, the potential effect of these couplings on inhibition and thus inhibitor design is largely unexplored. The present study examines the interdependency of subsites in HIV-1 protease using a focused library of protease inhibitors, to aid in future inhibitor design. Previously a series of darunavir (DRV) analogs was designed to systematically probe the S1' and S2' subsites. Co-crystal structures of these analogs with HIV-1 protease provide the ideal opportunity to probe subsite interdependency. …


Nontrivial Solutions Of Inclusions Involving Perturbed Maximal Monotone Operators, Dhruba Adhikari Jun 2017

Nontrivial Solutions Of Inclusions Involving Perturbed Maximal Monotone Operators, Dhruba Adhikari

Dhruba Adhikari

No abstract provided.


Recursive Non-Local Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie Jun 2017

Recursive Non-Local Means Filter For Video Denoising, Redha A. Ali, Russell C. Hardie

Russell C. Hardie

In this paper, we propose a computationally efficient algorithm for video denoising that exploits temporal and spatial redundancy. The proposed method is based on non-local means (NLM). NLM methods have been applied successfully in various image denoising applications. In the single-frame NLM method, each output pixel is formed as a weighted sum of the center pixels of neighboring patches, within a given search window. The weights are based on the patch intensity vector distances. The process requires computing vector distances for all of the patches in the search window. Direct extension of this method from 2D to 3D, for video …


Block Matching And Wiener Filtering Approach To Optical Turbulence Mitigation And Its Application To Simulated And Real Imagery With Quantitative Error Analysis, Russell C. Hardie, Michael Armand Rucci, Barry K. Karch, Alexander J. Dapore Jun 2017

Block Matching And Wiener Filtering Approach To Optical Turbulence Mitigation And Its Application To Simulated And Real Imagery With Quantitative Error Analysis, Russell C. Hardie, Michael Armand Rucci, Barry K. Karch, Alexander J. Dapore

Russell C. Hardie

We present a block-matching and Wiener filtering approach to atmospheric turbulence mitigation for long-range imaging of extended scenes. We evaluate the proposed method, along with some benchmark methods, using simulated and real-image sequences. The simulated data are generated with a simulation tool developed by one of the authors. These data provide objective truth and allow for quantitative error analysis. The proposed turbulence mitigation method takes a sequence of short-exposure frames of a static scene and outputs a single restored image. A block-matching registration algorithm is used to provide geometric correction for each of the individual input frames. The registered frames …


Simulation Of Anisoplanatic Imaging Through Optical Turbulence Using Numerical Wave Propagation With New Validation Analysis, Russell C. Hardie, Jonathan D. Power, Daniel A. Lemaster, Douglas R. Droege, Szymon Gladysz, Santasri Bose-Pillai Jun 2017

Simulation Of Anisoplanatic Imaging Through Optical Turbulence Using Numerical Wave Propagation With New Validation Analysis, Russell C. Hardie, Jonathan D. Power, Daniel A. Lemaster, Douglas R. Droege, Szymon Gladysz, Santasri Bose-Pillai

Russell C. Hardie

We present a numerical wave propagation method for simulating imaging of an extended scene under anisoplanatic conditions. While isoplanatic simulation is relatively common, few tools are specifically designed for simulating the imaging of extended scenes under anisoplanatic conditions. We provide a complete description of the proposed simulation tool, including the wave propagation method used. Our approach computes an array of point spread functions (PSFs) for a two-dimensional grid on the object plane. The PSFs are then used in a spatially varying weighted sum operation, with an ideal image, to produce a simulated image with realistic optical turbulence degradation. The degradation …


Differential Tilt Variance Effects Of Turbulence In Imagery: Comparing Simulation With Theory, Daniel A. Lemaster, Russell C. Hardie, Szymon Gladysz, Matthew D. Howard, Michael Armand Rucci, Matthew E. Trippel, Jonathan D. Power, Barry K. Karch Jun 2017

Differential Tilt Variance Effects Of Turbulence In Imagery: Comparing Simulation With Theory, Daniel A. Lemaster, Russell C. Hardie, Szymon Gladysz, Matthew D. Howard, Michael Armand Rucci, Matthew E. Trippel, Jonathan D. Power, Barry K. Karch

Russell C. Hardie

Differential tilt variance is a useful metric for interpreting the distorting effects of turbulence in incoherent imaging systems. In this paper, we compare the theoretical model of differential tilt variance to simulations. Simulation is based on a Monte Carlo wave optics approach with split step propagation. Results show that the simulation closely matches theory. The results also show that care must be taken when selecting a method to estimate tilts.


Design Of Batrun Distributed Processing System, Fredy Tandiary, Suraj C. Kothari, Ashish Dixit Jun 2017

Design Of Batrun Distributed Processing System, Fredy Tandiary, Suraj C. Kothari, Ashish Dixit

Suraj Kothari

This paper discusses the design of BATRUN Distributed Processing System (DPS). We have developed this system to automate the execution of jobs in a cluster of workstations where machines belong to different owners. The objective is to use a general purpose cluster as one massive computer for processing large applications. In contrast to a dedicated cluster, the scheduling in BATRUN DPS must ensure that only the idle cycles are used for distributed computing and local users, when they are operating, have the full control of their machines. BATRUN DPS has several unique features: (1) group-based scheduling policy to ensure execution …


Estimating Pay Gaps For Workers With Disabilities: Implications From Broadening Definitions And Data Sets, Kevin F. Hallock, Xin Jin, Linda Barrington Jun 2017

Estimating Pay Gaps For Workers With Disabilities: Implications From Broadening Definitions And Data Sets, Kevin F. Hallock, Xin Jin, Linda Barrington

Kevin F Hallock

Purpose: To compare pay gap estimates across 3 different national survey data sets for people with disabilities relative to those without disabilities when pay is measured as wage and salary alone versus a (total compensation) definition that includes an estimate of the value of benefits.

Method: Estimates of the cost to the employers of employee benefits at the occupational level from an employer survey data set are matched to individual-level data in each of the 3 data sets. Multiple regression techniques are applied to estimate wage and salary and total compensation gaps between full-time men with and without …


Discrimination By Gender And Disability Status: Do Worker Perceptions Match Statistical Measures?, Kevin F. Hallock, Wallace Hendricks, Emer Broadbent Jun 2017

Discrimination By Gender And Disability Status: Do Worker Perceptions Match Statistical Measures?, Kevin F. Hallock, Wallace Hendricks, Emer Broadbent

Kevin F Hallock

We explore whether perceptions of discrimination are related to ordinary statistical measures. The majority of disabled respondents report feeling some discrimination due to their disability, the majority of women feel some discrimination because of their gender, and a surprising number of men also report some discrimination. We do not find a strong link between perceptions of discrimination and measured discrimination perhaps because those who perceive discrimination feel that it occurs along other dimensions than pay. However, we do find a connection between whether a person feels his or her income is inadequate and measured discrimination for all groups studied.


Icmat 2017_Mv_Ecu-Final.Pptx, Mikhail Vasiliev, Kamal Alameh, Mohammad Nur-E-Alam, Victor Rosenberg Jun 2017

Icmat 2017_Mv_Ecu-Final.Pptx, Mikhail Vasiliev, Kamal Alameh, Mohammad Nur-E-Alam, Victor Rosenberg

Mikhail Vasiliev

No abstract provided.


Engineering And Verifying Requirements For Programmable Self-Assembling Nanomachines, Robyn Lutz, Jack Lutz, James Lathrop, Titus Klinge, Eric Henderson, Davita Mathur, Dalia Abo Sheasha Jun 2017

Engineering And Verifying Requirements For Programmable Self-Assembling Nanomachines, Robyn Lutz, Jack Lutz, James Lathrop, Titus Klinge, Eric Henderson, Davita Mathur, Dalia Abo Sheasha

Robyn Lutz

We propose an extension of van Lamsweerde's goal-oriented requirements engineering to the domain of programmable DNA nanotechnology. This is a domain in which individual devices (agents) are at most a few dozen nanometers in diameter. These devices are programmed to assemble themselves from molecular components and perform their assigned tasks. The devices carry out their tasks in the probabilistic world of chemical kinetics, so they are individually error-prone. However, the number of devices deployed is roughly on the order of a nanomole (a 6 followed by fourteen 0s), and some goals are achieved when enough of these agents achieve their …


A Management Maturity Model (Mmm) For Project-Based Organisational Performance Assessment, Craig Langston, Amir Ghanbaripour Jun 2017

A Management Maturity Model (Mmm) For Project-Based Organisational Performance Assessment, Craig Langston, Amir Ghanbaripour

Amir Ghanbaripour

Common sense suggests that organisations are more likely to deliver successful projects if they have systems in place that reflect a mature project environment based on a culture of continuous improvement. This paper develops and discusses a Management Maturity Model (MMM) to assess the maturity of project management organisations through a customisable, systematic, strategic and practical methodology inspired from the seminal work of Darwin, Deming, Drucker and Daniel. The model presented is relevant to organisations, such as construction and engineering companies, that prefer to use the Project Management Body of Knowledge (PMBOK™ Guide) published by the Project Management Institute (PMI), …


Microscopic Origins Of The Large Piezoelectricity Of Leadfree (Ba,Ca)(Zr,Ti)O3, Yousra Nahas, Alireza Akbarzadeh, Sergei Prokhorenko, Sergey Prosandeev, Raymond Walter, Igor Kornev, Jorgé Íñiguez, Laurent Bellaiche Jun 2017

Microscopic Origins Of The Large Piezoelectricity Of Leadfree (Ba,Ca)(Zr,Ti)O3, Yousra Nahas, Alireza Akbarzadeh, Sergei Prokhorenko, Sergey Prosandeev, Raymond Walter, Igor Kornev, Jorgé Íñiguez, Laurent Bellaiche

Raymond Walter

In light of directives around the world to eliminate toxic materials in various technologies, finding lead-free materials with high piezoelectric responses constitutes an important current scientific goal. As such, the recent discovery of a large electromechanical conversion near room temperature in (1 x)Ba(Zr0.2Ti0.8)O3 x(Ba0.7Ca0.3)TiO3 compounds has directed attention to understanding its origin. Here, we report the development of a large-scale atomistic scheme providing a microscopic insight into this technologically promising material. We find that its high piezoelectricity originates from the existence of large fluctuations of polarization in the …


Recursive Robust Pca Or Recursive Sparse Recovery In Large But Structured Noise, Chenlu Qiu, Namrata Vaswani, Brian Lois, Leslie Hogben Jun 2017

Recursive Robust Pca Or Recursive Sparse Recovery In Large But Structured Noise, Chenlu Qiu, Namrata Vaswani, Brian Lois, Leslie Hogben

Namrata Vaswani

This paper studies the recursive robust principal components analysis problem. If the outlier is the signal-of-interest, this problem can be interpreted as one of recursively recovering a time sequence of sparse vectors, St, in the presence of large but structured noise, Lt. The structure that we assume on Lt is that Lt is dense and lies in a low-dimensional subspace that is either fixed or changes slowly enough. A key application where this problem occurs is in video surveillance where the goal is to separate a slowly changing background (Lt) from moving foreground objects (St) on-the-fly. To solve the above …


Hot Topics In Cloud Computing, Liang-Jie Zhang, Jia Zhang, Jinan Fiaidhi, J. Morris Chang Jun 2017

Hot Topics In Cloud Computing, Liang-Jie Zhang, Jia Zhang, Jinan Fiaidhi, J. Morris Chang

Morris Chang

No abstract provided.


A Quantitative Cost/Benefit Analysis For Dynamic Updating, Bashar Gharaibeh, Hridesh Rajan, J. Morris Chang Jun 2017

A Quantitative Cost/Benefit Analysis For Dynamic Updating, Bashar Gharaibeh, Hridesh Rajan, J. Morris Chang

Morris Chang

Dynamic software updating provides many benefits, e.g. in runtime monitoring, runtime adaptation to fix bugs in long running applications, etc. Although it has several advantages, no quantitative analysis of its costs and revenue are available to show its benefits or limitations especially in comparison with other software updating schemes. To address this limitation in evaluating software updating schemes, we contribute a quantitative cost/benefit analysis based on net option-value model, which stems from the analysis of financial options. Our model expresses the relation between added value and paid cost in mathematical forms. We have used this model to evaluate the revenue …


Towards Efficient Java Virtual Machine Support For Dynamic Deployment Of Inter-Type Declarations, Bashar Gharaibeh, Hridesh Rajan, J. Morris Chang Jun 2017

Towards Efficient Java Virtual Machine Support For Dynamic Deployment Of Inter-Type Declarations, Bashar Gharaibeh, Hridesh Rajan, J. Morris Chang

Morris Chang

Dynamic deployment is an important feature of an aspect-oriented language design that has many applications, e.g. in runtime monitoring, runtime adaptation to fix bugs or add features to long running applications, runtime update of dynamic policy changes, etc. Many recently proposed language designs support these use cases. In previous work, researchers have demonstrated that the ability to support unanticipated deployment enables simpler and often more efficient implementations. These works have addressed an important subset of aspect-oriented features namely those that can be represented as the pointcut-advice model. In this work, we describe the design, formal semantics, and implementation of our …


A Smartphone-Based Device For Measuring Soil Organic Matter, Meng Lu Jun 2017

A Smartphone-Based Device For Measuring Soil Organic Matter, Meng Lu

Meng Lu

The project evaluated the potential of utilizing a smartphone-based system for the in-field analysis of Soil Organic Matter. Although it demonstrated that the performance of the smartphone-based spectrometer can be comparable to commercial spectrometers, the results suggest that it is challenging to identify the spectral “signatures” of the SOM due to the morphology and moisture variation of soil samples.


A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu Jun 2017

A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu

Meng Lu

Our interest in studying reactions catalyzed by high surface area W03 powders is based on their potential application as the active material in sensors for low level (ppb) detection of flammable or toxic gases. A series of porous W03 powders with both meso- and micro-porosity have been synthesized by Waghe and Tripp. Preliminary results of the response of sensors fabricated from these materials indicated the possibility of size selectivity on the molecular scale. To provide support for the hypothesis of size selectivity and understand the reaction kinetics of alcohols over the new porous W03 powders for sensor applications, we have …


An Examination Of A Theory Of Embodied Social Presence In Virtual Worlds, Brian E. Mennecke, Janea L. Triplett, Lesya M. Hassall, Zayira Jordán Conde, Rex Heer Jun 2017

An Examination Of A Theory Of Embodied Social Presence In Virtual Worlds, Brian E. Mennecke, Janea L. Triplett, Lesya M. Hassall, Zayira Jordán Conde, Rex Heer

Lesya Hassall

In this article, we discuss and empirically examine the importance of embodiment, context, and spatial proximity as they pertain to collaborative interaction and task completion in virtual environments. Specifically, we introduce the embodied social presence (ESP) theory as a framework to account for a higher level of perceptual engagement that users experience as they engage in activity-based social interaction in virtual environments. The ESP theory builds on the analysis of reflection data from Second Life users to explain the process by which perceptions of ESP are realized. We proceed to describe implications of ESP for collaboration and other organizational functions.


The Soil Moisture Velocity Equation, Fred L. Ogden, Craig C. Douglas Jun 2017

The Soil Moisture Velocity Equation, Fred L. Ogden, Craig C. Douglas

Fred L. Ogden

Numerical solution of the one-dimensional Richards’ equation is the recommended method for coupling groundwater to the atmosphere through the vadose zone in hyper-resolution Earth system models, but requires fine spatial discretization, is computationally expensive, and may not converge due to mathematical degeneracy or when sharp wetting fronts occur. We transformed the one-dimensional Richards’ equation into a new equation that describes the velocity of moisture content values in an unsaturated soil under the actions of capillarity and gravity. We call this new equation the Soil Moisture Velocity Equation (SMVE). The SMVE consists of two terms: an advection-like term that accounts for …


The Use And Effectiveness Of Online Social Media In Volunteer Organizations, Amy J. Connolly Jun 2017

The Use And Effectiveness Of Online Social Media In Volunteer Organizations, Amy J. Connolly

Amy J Connolly

Volunteer organizations face two challenges not found in non-volunteer organizations: recruiting and retaining volunteers. While social media use is increasing amongst individuals, its use and effectiveness for volunteer recruitment and retention by volunteer organizations is unknown. The dissertation reports the results of three studies to investigate this important question. Using a mixed-methods approach, it addressed the dual nature of social media and its effectiveness by including volunteer organizations and social media users. This dissertation found that although volunteer organizations are not using social media effectively, they could virtualize requirements of the recruitment process by focusing on relatable events instead of …


The Use And Effectiveness Of Online Social Media In Volunteer Organizations, Amy J. Connolly Jun 2017

The Use And Effectiveness Of Online Social Media In Volunteer Organizations, Amy J. Connolly

Amy J Connolly

Volunteer organizations face two challenges not found in non-volunteer organizations: recruiting and retaining volunteers. While social media use is increasing amongst individuals, its use and effectiveness for volunteer recruitment and retention by volunteer organizations is unknown. The dissertation reports the results of three studies to investigate this important question. Using a mixed-methods approach, it addressed the dual nature of social media and its effectiveness by including volunteer organizations and social media users. This dissertation found that although volunteer organizations are not using social media effectively, they could virtualize requirements of the recruitment process by focusing on relatable events instead of …


Enhancing Informative Frame Filtering By Water And Bubble Detection In Colonoscopy Videos, Ashok Dahal, Junghwan Oh, Wallapak Tavanapong, Johnny S. Wong, Piet C. De Groen Jun 2017

Enhancing Informative Frame Filtering By Water And Bubble Detection In Colonoscopy Videos, Ashok Dahal, Junghwan Oh, Wallapak Tavanapong, Johnny S. Wong, Piet C. De Groen

Johnny Wong

Colonoscopy has contributed to a marked decline in the number of colorectal cancer related deaths. However, recent data suggest that there is a significant (4-12%) miss-rate for the detection of even large polyps and cancers. To address this, we have been investigating an ‘automated feedback system’ which informs the endoscopist of possible sub-optimal inspection during colonoscopy. A fundamental step of this system is to distinguish non-informative frames from informative ones. Existing methods for this cannot classify water/bubble frames as non-informative even though they do not carry any useful visual information of the colon mucosa. In this paper, we propose a …


Quo Vadis-A Framework For Intelligent Routing In Large Communication Networks., Armin Mikler, Johnny S. Wong, Vasant Honavar Jun 2017

Quo Vadis-A Framework For Intelligent Routing In Large Communication Networks., Armin Mikler, Johnny S. Wong, Vasant Honavar

Johnny Wong

This paper presents Quo Vadis, an evolving framework for intelligent traffic management in very large communication networks. Quo Vadis is designed to exploit topological properties of large networks as well as their spatio-temporal dynamics to optimize multiple performance criteria through cooperation among nodes in the network. It employs a distributed representation of network state information using local load measurements supplemented by a less precise global summary. Routing decisions in Quo Vadis are based on parameterized heuristics designed to optimize various performance metrics in an anticipatory or pro-active as well as compensatory or reactive mode and to minimize the overhead associated …


An Object Oriented Approach To Modeling And Simulation Of Routing In Large Communication Networks, Armin Mikler, Johnny S. Wong, Vasant Honavar Jun 2017

An Object Oriented Approach To Modeling And Simulation Of Routing In Large Communication Networks, Armin Mikler, Johnny S. Wong, Vasant Honavar

Johnny Wong

The complexity (number of entities, interactions between entities, and resulting emergent dynamic behavior) of large communication environments which contain hundreds of nodes and links make simulation an important tool for the study of such systems. Given the difficulties associated with complete analytical treatment of complex dynamical systems, it is often the only practical tool that is available. This paper presents an example of a flexible, modular, object-oriented toolbox designed to support modeling and experimental analysis of a large family of heuristic knowledge representation and decision functions for adaptive self-managing communication networks with particular emphasis on routing strategies. It discusses in …


Feature Selection In Intrusion Detection System Over Mobile Ad-Hoc Network, Xia Wang, Tu-Liang Lin, Johnny S. Wong Jun 2017

Feature Selection In Intrusion Detection System Over Mobile Ad-Hoc Network, Xia Wang, Tu-Liang Lin, Johnny S. Wong

Johnny Wong

As Mobile ad-hoc network (MANET) has become a very important technology the security problem, especially, intrusion detection technique research has attracted many people�s effort. MANET is more vulnerable than wired network and suffers intrusion like wired network. This paper investigated some intrusion detection techniques using machine learning and proposed a profile based neighbor monitoring intrusion detection method. Further analysis shows that the features collected by each node are too many for wireless devices with limited capacity. We apply Markov Blanket algorithm [1] to the feature selection of the intrusion detection method. Experimental studies have shown that Markov Blanket algorithm can …


Quo Vadis - Adaptive Heuristics For Routing In Large Communication Networks, Armin Mikler, Johnny S. Wong, Vasant Honavar Jun 2017

Quo Vadis - Adaptive Heuristics For Routing In Large Communication Networks, Armin Mikler, Johnny S. Wong, Vasant Honavar

Johnny Wong

This paper presents Quo Vadis, an evolving framework for intelligent traffic management in very large communication networks. Quo Vadis is designed to exploit topological properties of large networks as well as their spatio-temporal dynamics to optimize multiple performance criteria through cooperation among nodes in the network. It employs a distributed representation of network state information using local load measurements supplemented by a less precise global summary. Routing decisions in Quo Vadis are based on parameterized heuristics designed to optimize various performance metrics in an anticipatory or pro-active as well as compensatory or reactive mode and to minimize the overhead associated …


Tree-Based Algorithm To Find The K-Th Value In Distributed Systems, Yoonsik Cheon, Johnny S. Wong Jun 2017

Tree-Based Algorithm To Find The K-Th Value In Distributed Systems, Yoonsik Cheon, Johnny S. Wong

Johnny Wong

In this paper, we study distributed algorithms for finding the k-th value in the decentralized systems. First we consider the case of circular configuration of processors where no processor knows the total number of participants. Later a network of arbitrary configuration is examined and a tree-based algorithm is proposed. The proposed algorithm requires O(N) messages and O(log N) rounds of message passing, where N is the number of nodes in the network.