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2010

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Articles 6271 - 6300 of 8625

Full-Text Articles in Physical Sciences and Mathematics

Development, Delivery And Dynamics Of A Digital Forensics Subject, Tanveer A. Zia Jan 2010

Development, Delivery And Dynamics Of A Digital Forensics Subject, Tanveer A. Zia

Australian Digital Forensics Conference

Digital forensics is a newly developed subject offered at Charles Sturt University (CSU). This subject serves as one of the core subjects for Master of Information Systems Security (Digital Forensics stream) course. The subject covers the legislative, regulatory, and technical aspects of digital forensics. The modules provide students detailed knowledge on digital forensics legislations, digital crime, forensics processes and procedures, data acquisition and validation, e-discovery tools, e-evidence collection and preservation, investigating operating systems and file systems, network forensics, email and web forensics, presenting reports and testimony as an expert witness. This paper summarises the process of subject development, delivery, assessments, …


Tuning The Magnetic And Electronic Properties Of Bilayer Graphene Nanoribbons On Si(001) By Bias Voltage, Zhuhua Zhang, Changfeng Chen, Xiao Cheng Zeng, Wanlin Guo Jan 2010

Tuning The Magnetic And Electronic Properties Of Bilayer Graphene Nanoribbons On Si(001) By Bias Voltage, Zhuhua Zhang, Changfeng Chen, Xiao Cheng Zeng, Wanlin Guo

Xiao Cheng Zeng Publications

We report on a systematic study of bias-voltage-induced modulation of magnetic and electronic properties of bilayer zigzag graphene nanoribbons (Z-GNRs) on Si(001) substrate by first-principles calculations. We show that the intrinsically nonmagnetic bilayer Z-GNRs exhibit magnetic ordering on the top layer while the bottom layer serves as a nonmagnetic buffer layer when adsorbed on the substrate. Interestingly, the adsorbed bilayers display distinct ribbon-width-dependent magnetoelectric effect under bias voltages. The magnetoelectric coefficient oscillates with increasing ribbon width, which arises from an interesting interplay of the interaction of the bottom ribbon layer with the substrates and the decay length of the localized …


Observation Of Earlier Two-To-Three Dimensional Structural Transition In Gold Cluster Anions By Isoelectronic Substitution: MauN- (N=8–11; M=Ag,Cu), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2010

Observation Of Earlier Two-To-Three Dimensional Structural Transition In Gold Cluster Anions By Isoelectronic Substitution: MauN- (N=8–11; M=Ag,Cu), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

The effects of isoelectronic substitution on the electronic and structural properties of gold clusters are investigated in the critical size range of the two-dimensional (2D)-three-dimensional (3D) structural transition (MAun, n=8–11; M=Ag,Cu) using photoelectron spectroscopy and density functional calculations. Photoelectron spectra of MAun are found to be similar to those of the bare gold clusters Aun+1 , indicating that substitution of a Au atom by a Ag or Cu atom does not significantly alter the geometric and electronic structures of the clusters. The only exception occurs at n …


Isomer Identification And Resolution In Small Gold Clusters, Wei Huang, Rhitankar Pal, Lei-Ming Wang, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2010

Isomer Identification And Resolution In Small Gold Clusters, Wei Huang, Rhitankar Pal, Lei-Ming Wang, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

A variety of experimental techniques are used to resolve energetically close isomers of Au7 and Au8 by combining photoelectron spectroscopy and ab initio calculations. Two structurally distinct isomers are confirmed to exist in the cluster beam for both clusters. Populations of the different isomers in the cluster beam are tuned using Ar-tagging, O2-titration, and isoelectronic atom substitution by Cu and Ag. A new isomer structure is found for Au7, which consists of a triangular Au6 unit with a dangling Au atom. Isomer-specific photoelectron spectra of Au8 are obtained …


Two-Dimensional To Three-Dimensional Structural Transition Of Gold Cluster Au 10 During Soft Landing On Tio 2 Surface And Its Effect On Co Oxidation, Hui Li, Yong Pei, Xiao Cheng Zeng Jan 2010

Two-Dimensional To Three-Dimensional Structural Transition Of Gold Cluster Au 10 During Soft Landing On Tio 2 Surface And Its Effect On Co Oxidation, Hui Li, Yong Pei, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We investigate the possible structural transition of a planar Au10 cluster during its soft landing on a TiO2 (110) surface with or with no oxygen defects. The collision between the gold cluster and the oxide surface is simulated using the Car–Parrinello quantum molecular dynamics method. Both high-speed and low-speed conditions typically implemented in soft-landing experiments are simulated. It is found that under a high-speed condition, the gold cluster Au10 can undergo a sequence of structural transitions after colliding with a defect-free TiO2 (110) surface. When the TiO2 (110) surface possesses oxygen vacancies, however, chemical bonds …


Icosahedral B12-Containing Core–Shell Structures Of B80, Hui Li, Nan Shao, Bo Shang, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng Jan 2010

Icosahedral B12-Containing Core–Shell Structures Of B80, Hui Li, Nan Shao, Bo Shang, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Low-lying icosahedral (Ih) B12-containing structures of B80 are explored, and a number of core–shell isomers are found to have lower energy than the previous predicted B80 fullerene. The structural transformation of boron clusters from tubular structure to core–shell structure may occur at a critical size less than B80.


Graphene-Like Bilayer Hexagonal Silicon Polymorph, Jaeil Bai, Hideki Tanaka, Xiao Cheng Zeng Jan 2010

Graphene-Like Bilayer Hexagonal Silicon Polymorph, Jaeil Bai, Hideki Tanaka, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We present molecular dynamics simulation evidence for a freezing transition from liquid silicon to quasi-twodimensional (quasi-2D) bilayer silicon in a slit nanopore. This new quasi-2D polymorph of silicon exhibits a bilayer hexagonal structure in which the covalent coordination number of every silicon atom is four. Quantum molecular dynamics simulations show that the stand-alone bilayer silicon (without the confinement) is still stable at 400 K. Electronic band-structure calculations suggest that the bilayer hexagonal silicon is a quasi-2D semimetal, similar to a graphene monolayer, but with an indirect zero band gap.


Packing Rates Of Measures And A Conjecture For The Packing Density Of 2413, C. B. Presutti, Walter Stromquist Jan 2010

Packing Rates Of Measures And A Conjecture For The Packing Density Of 2413, C. B. Presutti, Walter Stromquist

Mathematics & Statistics Faculty Works

We give a new lower bound of 0.10472422757673209041 for the packing density of 2413, justify it by a construction, and conjecture that this value is actually equal to the packing density. Along the way we define the packing rate of a permutation with respect to a measure, and show that maximizing the packing rate of a pattern over all measures gives the packing density of the pattern.


Implications Of Stunting On Morphology Of Freshwater Fishes, Christopher J. Chizinski, Kevin L. Pope, G.R. Wilde, R.E. Strauss Jan 2010

Implications Of Stunting On Morphology Of Freshwater Fishes, Christopher J. Chizinski, Kevin L. Pope, G.R. Wilde, R.E. Strauss

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The purpose of this study was to assess morphological differences between stunted and non-stunted white perch Morone americana and green sunfish Lepomis cyanellus. Few female M. americana were captured; thus, morphological differences between adult males and juveniles were assessed for M. americana. Similarly, few immature (juvenile) L. cyanellus were captured for the stunted morphotype; thus, male and female morphological differences were assessed for L. cyanellus. Features of the head tended to be relatively larger in stunted fish of both species, whereas the mid-body tended to be relatively larger in non-stunted M. americana, but not in non-stunted …


The Effect Of Predation On Stunted And Nonstunted White Perch, Nathan J.C. Gosch, L. L. Pierce, Kevin L. Pope Jan 2010

The Effect Of Predation On Stunted And Nonstunted White Perch, Nathan J.C. Gosch, L. L. Pierce, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Predation is widely regarded as a means to prevent or minimise the establishment of a stunted (high density of slow growing individuals) population. We investigated the effect of predation on two different white perch Morone americana populations (stunted and nonstunted) by examining the stomach contents of piscivorous fishes. White perch and gizzard shad dominated piscivore diets in Branched Oak Lake, whereas white perch dominated piscivore diets in Pawnee Lake. White perch consumed in the stunted population (Branched Oak Lake) were larger and older than white perch consumed in the nonstunted population (Pawnee Lake). Many of the consumed white perch in …


Food Habits Of Stunted And Non-Stunted White Perch (Marone Americana), Nathan J.C. Gosch, Jeffrey R. Stittle, Kevin L. Pope Jan 2010

Food Habits Of Stunted And Non-Stunted White Perch (Marone Americana), Nathan J.C. Gosch, Jeffrey R. Stittle, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We studied food habits of white perch (Morone americana) from two populations with different stable states (stunted [Branched Oak Lake, Nebraska] and non-stunted [Pawnee Lake, Nebraska]) to determine if change in food habits of white perch is likely to occur in situations where a stunted while perch population is altered to a non-stunted state and vice versa. Three approaches were used to quantitatively describe seasonal (spring= March-May, summer= June-August, autumn = September-November) diets of white perch - 1) frequency of occurrence, 2) percentage of composition by volume, and 3) mean stomach fullness. White perch diets were dominated by …


A Unified Solution To Scan Test Volume, Time, And Power Minimization, Zhen Chen, Sharad C. Seth, Dong Xiang, Bhargab B. Bhattacharya Jan 2010

A Unified Solution To Scan Test Volume, Time, And Power Minimization, Zhen Chen, Sharad C. Seth, Dong Xiang, Bhargab B. Bhattacharya

CSE Conference and Workshop Papers

The double-tree scan-path architecture, originally proposed for low test power, is adapted to simultaneously reduce the test application time and test data volume under external testing. Experimental results show significant performance improvements over other existing scan architectures.


Linear Programming Models For Multi-Channel P2p Streaming Systems, Miao Wang, Lisong Xu, Byrav Ramamurthy Jan 2010

Linear Programming Models For Multi-Channel P2p Streaming Systems, Miao Wang, Lisong Xu, Byrav Ramamurthy

CSE Conference and Workshop Papers

Most of the commercial P2P video streaming deployments support hundreds of channels and are referred to as multichannel systems. Measurement studies show that bandwidth resources of different channels are highly unbalanced and thus recent research studies have proposed various protocols to improve the streaming qualities for all channels by enabling cross-channel cooperation among multiple channels. However, there is no general framework for comparing existing and potential designs for multi-channel P2P systems. The goal of this paper is to establish tractable models for answering the fundamental question in multi-channel system designs: Under what circumstances, should a particular design be used to …


Spatio-Temporal Soil Moisture Measurement With Wireless Underground Sensor Networks, Xin Dong, Mehmet C. Vuran Jan 2010

Spatio-Temporal Soil Moisture Measurement With Wireless Underground Sensor Networks, Xin Dong, Mehmet C. Vuran

CSE Conference and Workshop Papers

In this paper, the estimation distortion of distributed soil moisture measurement using Wireless Underground Sensor Networks (WUSNs) is investigated. The main focus of this paper is to analyze the impact of the environment and network parameters on the estimation distortion of the soil moisture.More specifically, the effects of rainfall, soil porosity, and vegetation root zone are investigated by exploiting a rainfall model, in addition to the effects of sampling rate, network topology, and measurement signal noise ratio. Spatio-temporal correlation is characterized to develop a measurement distortion model with respect to these factors. The evaluations reveal that with porous soil and …


Cost Efficiency Of Anycast-Based Forwarding In Duty-Cycled Wsns With Lossy Channel, Yuyan Xue, Mehmet C. Vuran, Byrav Ramamurthy Jan 2010

Cost Efficiency Of Anycast-Based Forwarding In Duty-Cycled Wsns With Lossy Channel, Yuyan Xue, Mehmet C. Vuran, Byrav Ramamurthy

CSE Conference and Workshop Papers

Anycasting has been proposed recently as an efficient communication method for asynchronous duty-cycled wireless sensor networks. However, the interdependencies between end-toend communication cost and the anycasting design parameters have not been systematically studied. In this paper, a statistical endtoend cost model is presented to capture the end-to-end latency and energy consumption of anycasting operation under a realistic wireless channel model. By exploring the relationship between the end-to-end cost efficiency and the forwarding decision dependent anycasting design parameters, two anycasting forwarding metrics are proposed for fully distributed forwarding decision. By exploring the relationship among the preamble length, the size of the …


Stochastic Analysis Of Energy Consumption In Wireless Sensor Networks, Yunbo Wang, Mehmet C. Vuran, Steve Goddard Jan 2010

Stochastic Analysis Of Energy Consumption In Wireless Sensor Networks, Yunbo Wang, Mehmet C. Vuran, Steve Goddard

CSE Conference and Workshop Papers

Limited energy resources in increasingly sophisticated wireless sensor networks (WSNs) call for a comprehensive crosslayer analysis of energy consumption in a multi-hop network. For reliability analysis in such networks, the statistical information about energy consumption and lifetime is required. However, traditional energy analysis approaches only focus on the average energy consumed. In this paper, instead, we provide a stochastic analysis of the energy consumption in a random network environment. Accordingly, a comprehensive cross-layer analysis framework, which employs a stochastic queueing model, is developed. Using this framework, the distribution of energy consumption for nodes in WSNs during a given time period …


Preface, Berthe Y. Choueiry, Bob Givan Jan 2010

Preface, Berthe Y. Choueiry, Bob Givan

CSE Conference and Workshop Papers

The Tenth International Symposium on Artificial Intelligence and Mathematics (ISAIM 2008) gathered a fine and distinguished crowd of researchers active in mathematics, theoretical computer science, and artificial intelligence. The three-day meeting, held from January 2 to 4, 2008, in Fort Lauderdale, featured invited talks by keynote speakers David McAllester, Francesca Rossi and Naftali Tishby. The program also included special sessions on “Computation and Social Choice” (organized by Toby Walsh), “Effective Exploration in Active Learning and Reinforcement Learning” (organized by Pascal Poupart), and “Logic in Artificial Intelligence” (organized by Michael Kaminski and Miroslaw Truszczynski, and the subject of a separate special …


Use Biomedical Laboratories In Physics To Develop Student Reasoning, Robert G. Fuller Jan 2010

Use Biomedical Laboratories In Physics To Develop Student Reasoning, Robert G. Fuller

Robert G. Fuller Publications

The results of the “intrinsic motivation for learning” work by Thomas Malone (1) can be combined with the “development of reasoning” work by Robert Karplus (2) to create introductory physics laboratories that feature biomedical applications of physics. This presentation will discuss the attributes of the work of Malone and Karplus and illustrate how they can work together to construct physics laboratories that encourage the development of reasoning by students as well as intrigue them with biomedical applications. A concrete example will be given in a six-week module “How Do We See Color?” that was developed as part of the Humanized …


Computational Studies Of Stereochemical Effects In The Synthesis Of Sugar Mimics, Louis Anthony Lello Jan 2010

Computational Studies Of Stereochemical Effects In The Synthesis Of Sugar Mimics, Louis Anthony Lello

Senior Honors Theses and Projects

Density Functional methods are used to model the tandem aza-Cope rearrangement – Mannich cyclization reaction leading to substituted acylpyrrolidines. The ultimate goal is to determine optimum reaction conditions that maximize stereoselectivity, as only one set of stereoisomers is pharmacologically active. Three aspects of the reaction are investigated. First, we determine the relative size of three rotational barriers in the interconversion of two iminium cation stereoisomers that are precursors to the aza-Cope rearrangement. The lowest energy pathway for the interconversion is identified, as well as the relative stability of the two stereoisomers for two different substituents: diphenyl and methyl. Activation barriers …


Analysis And Estimation Of Motion Transmission Errors Of A Timing Belt Drive, Ergi̇n Kiliç, Meli̇k Dölen, Ahmet Buğra Koku Jan 2010

Analysis And Estimation Of Motion Transmission Errors Of A Timing Belt Drive, Ergi̇n Kiliç, Meli̇k Dölen, Ahmet Buğra Koku

Turkish Journal of Electrical Engineering and Computer Sciences

This paper focuses on viable position estimation schemes for timing belt drives where the position of the carriage (load) is to be determined via reference models receiving input from a position sensor attached to the actuator of the timing belt. A detailed analysis of the transmission error sources is presented, and a number of relevant mathematical models are developed using a priori knowledge of the process. This paper demonstrates that such schemes are very effective when the drive system is not subjected to external loads and operating conditions do not change considerably i.e. ambient temperature, belt tension.


The Principal Eigencurves For A Nonselfadjoint Elliptic Operator, Aomar Anane, Omar Chakrone, Abdellah Zerouali Jan 2010

The Principal Eigencurves For A Nonselfadjoint Elliptic Operator, Aomar Anane, Omar Chakrone, Abdellah Zerouali

Turkish Journal of Mathematics

In this paper we study the existence of the principal eigencurves for a nonselfadjoint elliptic operator. We obtain their variational formulation. We establish also the continuity and the differentiability of the principal eigencurves.


Weak Hardy Space And Endpoint Estimates For Singular Integrals On Space Of Homogeneous Type, Yong Ding, Xinfeng Wu Jan 2010

Weak Hardy Space And Endpoint Estimates For Singular Integrals On Space Of Homogeneous Type, Yong Ding, Xinfeng Wu

Turkish Journal of Mathematics

We develop the theory of weak Hardy spaces H^{1,\infty} on space of homogeneous type. As some applications, we show that certain singular integral operators and fractional integral operators are bounded from H^{1,\infty} to L^{1,\infty} and L^{\frac{1}{1-\alpha},\infty}, respectively. We give also the endpoint estimates for Nagel and Stein's singular integrals studied in [10].


Traveling Wavefronts In A Single Species Model With Nonlocal Diffusion And Age-Structure, Xue-Shi Li, Guo Lin Jan 2010

Traveling Wavefronts In A Single Species Model With Nonlocal Diffusion And Age-Structure, Xue-Shi Li, Guo Lin

Turkish Journal of Mathematics

This paper is concerned with the existence of monotone traveling wavefronts in a single species model with nonlocal diffusion and age-structure. We first apply upper and lower solution technique to prove the result if the wave speed is larger than a threshold depending only on the basic parameters. When the wave speed equals to the threshold, we show the conclusion by passing to a limit function.


Warped Product Semi-Slant Submanifolds In Kenmotsu Manifolds, Mehmet Atçeken Jan 2010

Warped Product Semi-Slant Submanifolds In Kenmotsu Manifolds, Mehmet Atçeken

Turkish Journal of Mathematics

In this paper, we research the existence or non-existence of warped product semi-slant submanifolds in Kenmotsu manifolds. Consequently, we see that there are no proper warped product semi-slant submanifolds in Kenmotsu manifolds such that totally geodesic and totally umbilical submanifolds of warped product are proper semi-slant and invariant (or anti-invariant), respectively.


The Essential Norm Of A Composition Operator On Orlicz Spaces, M. R. Jabbarzadeh Jan 2010

The Essential Norm Of A Composition Operator On Orlicz Spaces, M. R. Jabbarzadeh

Turkish Journal of Mathematics

In this note we determine the lower and upper estimates for the essential norm of a composition operator on the Orlicz spaces under certain conditions.


Number Of Pseudo--Anosov Elements In The Mapping Class Group Of A Four--Holed Sphere, Feri̇he Atalan, Mustafa Korkmaz Jan 2010

Number Of Pseudo--Anosov Elements In The Mapping Class Group Of A Four--Holed Sphere, Feri̇he Atalan, Mustafa Korkmaz

Turkish Journal of Mathematics

We compute the growth series and the growth functions of reducible and pseudo-Anosov elements of the pure mapping class group of the sphere with four holes with respect to a certain generating set. We prove that the ratio of the number of pseudo-Anosov elements to that of all elements in a ball with center at the identity tends to one as the radius of the ball tends to infinity.


Properties Of The Generalized Laplace Transform And Transport Partial Dynamic Equation On Time Scales, Chris R. Ahrendt Jan 2010

Properties Of The Generalized Laplace Transform And Transport Partial Dynamic Equation On Time Scales, Chris R. Ahrendt

Department of Mathematics: Dissertations, Theses, and Student Research

In this dissertation, we first focus on the generalized Laplace transform on time scales. We prove several properties of the generalized exponential function which will allow us to explore some of the fundamental properties of the Laplace transform. We then give a description of the region in the complex plane for which the improper integral in the definition of the Laplace transform converges, and how this region is affected by the time scale in question. Conditions under which the Laplace transform of a power series can be computed term-by-term are given. We develop a formula for the Laplace transform for …


Multi–Component Nls Models On Symmetric Spaces: Spectral Properties Versus Representations Theory, Vladimir Gerdjikov, Georgi Grahovski Jan 2010

Multi–Component Nls Models On Symmetric Spaces: Spectral Properties Versus Representations Theory, Vladimir Gerdjikov, Georgi Grahovski

Articles

The algebraic structure and the spectral properties of a special class of multicomponent NLS equations, related to the symmetric spaces of BD.I-type are analyzed. The focus of the study is on the spectral theory of the associated Lax operator to these nonlinear evolutionary equations for different fundamental representations of the underlying simple Lie algebra g. Special attention is paid to the spinor representation of the orthogonal Lie algebras of B type.


Magnetic Excitations In The Spinel Compound Liₓ [Mn₁.₉₆ Li₀.₀₄] O₄ (X=0.2,0.6,0.8,1.0 ): How A Classical System Can Mimic Quantum Critical Scaling, Thomas Heitmann, Alexander Schmets, John Gaddy, Jagat Lamsal, Marcus Petrovic, Thomas Vojta, Wouter Montfrooij Jan 2010

Magnetic Excitations In The Spinel Compound Liₓ [Mn₁.₉₆ Li₀.₀₄] O₄ (X=0.2,0.6,0.8,1.0 ): How A Classical System Can Mimic Quantum Critical Scaling, Thomas Heitmann, Alexander Schmets, John Gaddy, Jagat Lamsal, Marcus Petrovic, Thomas Vojta, Wouter Montfrooij

Physics Faculty Research & Creative Works

We present neutron-scattering results on the magnetic excitations in the spinel compounds Lix [Mn1.96 Li0.04] O4 (x=0.2,0.6,0.8,1.0). We show that the dominant excitations below T~70K are determined by Mn ions located in clusters, and that these excitations mimic the dynamic scaling found in quantum critical systems that also harbor magnetic clusters, such as CeRu0.5 Fe1.5 Ge2. We argue that our results for this classical spinel compound suggest that the unusual response at low temperatures as observed in quantum critical systems that have been driven to criticality through substantial chemical doping is …


Mobile Mapping System Lidar Data Framework, P. Lewis, C. Mcelhinney, Bianca Schoen-Phelan, T. Mccarthy Jan 2010

Mobile Mapping System Lidar Data Framework, P. Lewis, C. Mcelhinney, Bianca Schoen-Phelan, T. Mccarthy

Articles

Mobile Mapping Systems (MMSs) for infrastructural monitoring and mapping arebecoming more prevalent as the availability and affordability of solutions that generate high accuracy geospatial data has matured.However, no existent methodology or systemexists where all theLiDAR, video, navigation,infrared and multispectraldata sources,collected from thismobile platform are integrated into a single, comprehensivedata management solution. Based on empirical experience there is a need for an MMS-data management framework where these types of data can be dynamically accessed and integratedto enable different projects with varying objectives todynamically accessdifferent MMS-data for, in one example, use in feature extraction algorithms. In this paper we introduce the LiDAR …