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Dmctcp: Desynchronized Multi-Channel Tcp For High Speed Access Networks With Tiny Buffers, Cheng Cui, Lin Xue, Chui Hui Chiu, Praveenkumar Kondikoppa, Seung Jong Park Sep 2014

Dmctcp: Desynchronized Multi-Channel Tcp For High Speed Access Networks With Tiny Buffers, Cheng Cui, Lin Xue, Chui Hui Chiu, Praveenkumar Kondikoppa, Seung Jong Park

Computer Science Faculty Research & Creative Works

The past few years have witnessed debate on how to improve link utilization of high-speed tiny-size buffer routers. Widely argued proposals for TCP traffic to realize acceptable link capacities mandate: (i) over-provisioned core link bandwidth; and (ii) non-bursty flows; and (iii) tens of thousands of asynchronous flows. However, in high-speed access networks where flows are bursty, sparse and synchronous, TCP traffic suffer severely from routers with tiny buffers. We propose a new congestion control algorithm called Desyn-chronized Multi-Channel TCP (DMCTCP) that creates a flow with multiple channels. It avoids TCP loss synchronization by desynchronizing channels, and it avoids sending rate …

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E-Darwin: Energy Aware Disaster Recovery Network Using Wifi Tethering, Mayank Raj, Krishna Kant, Sajal K. Das Sep 2014

E-Darwin: Energy Aware Disaster Recovery Network Using Wifi Tethering, Mayank Raj, Krishna Kant, Sajal K. Das

Computer Science Faculty Research & Creative Works

In this paper, we propose a novel architecture called Energy Aware Disaster Recovery Network using Wi-Fi Tethering (E-DARWIN). The underlying idea is to make use of Wi-Fi Tethering technology ubiquitously available on wireless devices, like smartphones and tablets, to set up an ad hoc network for data collection in disaster scenarios. To this end, we design novel mechanisms, which aid in autonomous creation of the ad hoc network, distribution of data capturing task among the devices, and collection of data with minimum delay. Specifically, we design and implement a distributed coalition formation game for distributing the data capturing task among …

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Optimal Pmu Placement For Identification Of Multiple Power Line Outages In Smart Grids, Jie Wu, Jinjun Xiong, Prasenjit Shil, Yiyu Shi Sep 2014

Optimal Pmu Placement For Identification Of Multiple Power Line Outages In Smart Grids, Jie Wu, Jinjun Xiong, Prasenjit Shil, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Placing appropriate numbers of PMUs is critical to collect phase angle data for best identifying multiple line outages in wide-area transmission system, because of high deployment costs. This work focuses on exploring the global optimal strategy of PMU deployment for maximizing the average identification capability of multiple line outages. Inspired by Kullback-Leibler (KL) distance, this paper proposes the closed-form mathematical model to describe the average identification capability of multiple simultaneous line outages. Using IEEE 14-bus system, the optimal trade-off between the average identification capability and the number of PMUs is characterized. The proposed model successfully portrays the statistical identification performance …

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The Contour Deformation Method For Calculating The High Frequency Scattered Fields By The Fock Current On The Surface Of The 3-D Convex Cylinder, Yu Mao Wu, Li (Lijun) Jun Jiang, Weng Cho Chew Sep 2014

The Contour Deformation Method For Calculating The High Frequency Scattered Fields By The Fock Current On The Surface Of The 3-D Convex Cylinder, Yu Mao Wu, Li (Lijun) Jun Jiang, Weng Cho Chew

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, the Fock currents on the convex cylinders are comprehensively studied. The contour deformation method is invoked to calculate the highly oscillatory Fock currents. The computational process is frequency independent in workload. Then, quadratic phase approximation is proposed to efficiently solve the highly oscillatory scattered field. Numerical results for the high frequency scattered far fields on the convex cylinders are given to validate the efficiency of the proposed method. Furthermore, the contour deformation method for computing the Fock currents offers a clear high frequency wave physical picture.

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Effective Roughness Dielectric In A Pcb: Measurement And Full-Wave Simulation Verification, Tracey Vincent, Marina Koledintseva, Antonio Ciccomancini, Scott Hinaga Sep 2014

Effective Roughness Dielectric In A Pcb: Measurement And Full-Wave Simulation Verification, Tracey Vincent, Marina Koledintseva, Antonio Ciccomancini, Scott Hinaga

Electrical and Computer Engineering Faculty Research & Creative Works

Surface roughness topography of printed circuit boards (PCBs) needs to be included in SI simulations in order to accurately predict the insertion loss of the structure. An effective roughness dielectric (ERD) model can be used to substitute an inhomogeneous interface between copper foil and laminate dielectric in a PCB. Herein, this approach is tested for verification using 3D full-wave numerical simulations. These effective roughness dielectric layers with the appropriate complex permittivity are included in the modeling of strip line examples. The parameters of an ambient laminate dielectric free of conductor roughness effects in the strip line are determined using differential …

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A Generalized Proportionate Adaptive Algorithm Based On Convex Optimization, Jianming Liu, Steven L. Grant Sep 2014

A Generalized Proportionate Adaptive Algorithm Based On Convex Optimization, Jianming Liu, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

A general framework is proposed to derive proportionate adaptive algorithms for sparse system identification. The proposed algorithmic framework employs the convex optimization and covers many traditional proportionate algorithms. Meanwhile, based on this framework, some novel proportionate algorithms could be derived too. In the simulations, we compare the new derived proportionate algorithm with the traditional ones and demonstrate that it could provide faster convergence rate and tracking performance for both white and colored input in sparse system identification.

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Coherent-State Path Integrals In The Continuum, G. Kordas, Simeon I. Mistakidis, A. I. Karanikas Sep 2014

Coherent-State Path Integrals In The Continuum, G. Kordas, Simeon I. Mistakidis, A. I. Karanikas

Physics Faculty Research & Creative Works

We Discuss The Time Continuous Path Integration In The Coherent-State Basis In A Way That Is Free From Inconsistencies. Employing This Notion We Reproduce Known And Exact Results Working Directly In The Continuum. Such A Formalism Can Set The Basis To Develop Perturbative And Nonperturbative Approximations Already Known In The Quantum-Field-Theory Community. These Techniques Can Be Proven Useful In A Great Variety Of Problems Where Bosonic Hamiltonians Are Used.

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The Delta Test: The 1-Nn Estimator As A Feature Selection Criterion, Emil Eirola, Amaury Lendasse, Francesco Corona, Michel Verleysen Sep 2014

The Delta Test: The 1-Nn Estimator As A Feature Selection Criterion, Emil Eirola, Amaury Lendasse, Francesco Corona, Michel Verleysen

Engineering Management and Systems Engineering Faculty Research & Creative Works

Feature Selection is Essential in Many Machines Learning Problem, But It is Often Not Clear on Which Grounds Variables Should Be Included or Excluded. This Paper Shows that the Mean Squared Leave-One-Out Error of the First Nearest-Neighbour Estimator is Effective as a Cost Function When Selecting Input Variables for Regression Tasks. a Theoretical Analysis of the Estimator's Properties is Presented to Support its Use for Feature Selection. an Experimental Comparison to Alternative Selection Criteria (Including Mutual Information, Least Angle Regression, and the Rrelieff Algorithm) Demonstrates Reliable Performance on Several Regression Tasks.

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Variable Selection For Regression Problems Using Gaussian Mixture Models To Estimate Mutual Information, Emil Eirola, Amaury Lendasse, Juha Karhunen Sep 2014

Variable Selection For Regression Problems Using Gaussian Mixture Models To Estimate Mutual Information, Emil Eirola, Amaury Lendasse, Juha Karhunen

Engineering Management and Systems Engineering Faculty Research & Creative Works

Variable Selection is a Crucial Part of Building Regression Models and is Preferably Done as a Filtering Method Independently from the Model Training. Mutual Information is a Popular Relevance Criterion for This, But It is Not Trivial to Estimate Accurately from a Limited Amount of Data. in This Paper, a Method is Presented Where a Gaussian Mixture Model is Used to Estimate the Joint Density of the Input and Output Variables, and Subsequently Used to Select the Most Relevant Variables by Maximizing the Mutual Information Which Can Be Estimated using the Model.

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Missouri S&T Magazine Fall/Winter 2014, Missouri S&T Marketing And Communications Department, Miner Alumni Association Sep 2014

Missouri S&T Magazine Fall/Winter 2014, Missouri S&T Marketing And Communications Department, Miner Alumni Association

Missouri S&T Magazine

No abstract provided.

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Phase Transitions On Random Lattices: How Random Is Topological Disorder?, Hatem Barghathi, Thomas Vojta Sep 2014

Phase Transitions On Random Lattices: How Random Is Topological Disorder?, Hatem Barghathi, Thomas Vojta

Physics Faculty Research & Creative Works

We study the effects of topological (connectivity) disorder on phase transitions. We identify a broad class of random lattices whose disorder fluctuations decay much faster with increasing length scale than those of generic random systems, yielding a wandering exponent of ω = (d−1)/(2d) in d dimensions. The stability of clean critical points is thus governed by the criterion (d+1)ν > 2 rather than the usual Harris criterion dν > 2, making topological disorder less relevant than generic randomness. The Imry-Ma criterion is also modified, allowing first-order transitions to survive in all dimensions d > 1. These results explain a host of puzzling violations …

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Measurement Of Stiffness Anisotropy In Kaolinite Using Bender Element Tests In A Floating Wall Consolidometer, X. Kang, G. C. Kang, B. Bate Sep 2014

Measurement Of Stiffness Anisotropy In Kaolinite Using Bender Element Tests In A Floating Wall Consolidometer, X. Kang, G. C. Kang, B. Bate

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A new floating wall consolidometer-type bender element testing system was developed to study the stiffness anisotropy of clays at applied vertical stresses up to 800 kPa. One-dimensional slurry-consolidated Georgia RP-2 kaolinite samples, prepared with 0.005 and 1 mol/l NaCl solutions, were tested in this system. A floating wall design eliminated the detrimental bending moment that acts upon the horizontally installed benders as a result of soil settlement in a traditional fixed wall setup, which significantly improved the signal quality and bender reuse. Floating wall-soil interface resistance was quantified with pulling tests. Analytical equations were then derived to calculate the wall …

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Simplified Parallel Interference Cancelation For Underdetermined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang Sep 2014

Simplified Parallel Interference Cancelation For Underdetermined Mimo Systems, Chen Qian, Jingxian Wu, Yahong Rosa Zheng, Zhaocheng Wang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a low-complexity detection scheme is proposed for an underdetermined multiple-input-multiple-output (UD-MIMO) wireless communication system that employs N transmit antennas and M < N receive antennas. The proposed scheme combines a simplified parallel interference cancelation (S-PIC) with the block decision feedback equalization (BDFE) algorithm. To account for the extra (N - M)-dimension in the transmitted signal, the UD-MIMO system is partitioned into two subsystems: one with (N - M) transmit antennas and the other one with M transmit antennas. The interference from the first subsystem to the second one is canceled in parallel, and BDFE is performed over the second subsystem. Unlike conventional PIC methods that exhaustively search all the Q (N - M) sequences in the first subsystem, with Q being the constellation size, the proposed scheme explores only a small number of candidate sequences in the first subsystem; thus, it achieves significant complexity reduction. Two new candidate sequence selection methods are proposed. In the first iteration, the candidate sequences used for PIC are selected by exploring the statistical properties of the received signals. In the second iteration and beyond, the set containing the candidate sequences is constructed by utilizing the soft information generated from the previous iteration. The proposed scheme provides a balanced tradeoff between computational complexity and bit error rate (BER) performance.

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Finite-Size Effects On Molecular Dynamics Interfacial Thermal-Resistance Predictions, Zhi Liang, Pawel Keblinski Aug 2014

Finite-Size Effects On Molecular Dynamics Interfacial Thermal-Resistance Predictions, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using Molecular Dynamics Simulations, We Study the Role of Finite Size Effects on the Determination of Interfacial Thermal Resistance between Two Solids Characterized by High Phonon Mean Free Paths. in Particular, We Will Show that a Direct, Heat Source-Sink Method Leads to Strong Size Effect, Associated with Ballistic Phonon Transport to and From, and Specular Reflections at the Simulation Domain Boundary. Lack of Proper Account for These Effects Can Lead to Incorrect Predictions About the Role of Interfacial Bonding and Structure on Interfacial Thermal Resistance. We Also Show that the Finite Size Effect Can Be Dramatically Reduced by Introduction of …

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Thermographic Investigation Of Laser Metal Deposition, Sreekar Karnati, Todd E. Sparks, Frank W. Liou Aug 2014

Thermographic Investigation Of Laser Metal Deposition, Sreekar Karnati, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Primitive stages of studies on and with additive manufacturing techniques popularly involve thin wall geometry. In the current effort attempts were made to capture various thermal aspects during deposition of a thin wall geometry. The thermo-graphic data was captured using a FLIR A615 infrared camera. Post processing using edge detection algorithms and image processing techniques, the geometric and thermal aspects of meltpool and tail of the meltpool were obtained. The effect of geometry and power on shape of the meltpool and its tail were obtained. The depositions of SS 316 with varying power. These observations were discussed and analyzed in …

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Communication: Rigorous Quantum Dynamics Of O + O₂ Exchange Reactions On An Ab Initio Potential Energy Surface Substantiate The Negative Temperature Dependence Of Rate Coefficients, Yaqin Li, Zhigang Sun, Bin Jiang, Daiqian Xie, Richard Dawes, Hua Guo Aug 2014

Communication: Rigorous Quantum Dynamics Of O + O₂ Exchange Reactions On An Ab Initio Potential Energy Surface Substantiate The Negative Temperature Dependence Of Rate Coefficients, Yaqin Li, Zhigang Sun, Bin Jiang, Daiqian Xie, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

The kinetics and dynamics of several O + O2 isotope exchange reactions have been investigated on a recently determined accurate global O3 potential energy surface using a time-dependent wave packet method. The agreement between calculated and measured rate coefficients is significantly improved over previous work. More importantly, the experimentally observed negative temperature dependence of the rate coefficients is for the first time rigorously reproduced theoretically. This negative temperature dependence can be attributed to the absence in the new potential energy surface of a submerged "reef" structure, which was present in all previous potential energy surfaces. In addition, contributions …

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Mantle Transition Zone Discontinuities Beneath The Contiguous United States, Stephen S. Gao, Kelly H. Liu Aug 2014

Mantle Transition Zone Discontinuities Beneath The Contiguous United States, Stephen S. Gao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Using over 310,000 high-quality radial receiver functions recorded by the USArray and other seismic stations in the contiguous United States, the depths of the 410 km and 660 km discontinuities (d410 and d660) are mapped in over 1,000 consecutive overlapping circles with a radius of 1⁰. The average mantle transition zone (MTZ) thickness for both the western and central/eastern U.S. is within 3 km from the global average of 250 km, suggesting an overall normal MTZ temperature beneath both areas. The Pacific Coast Ranges and the southern Basin and Range Province are underlain by a depressed d410, indicating higher-than-normal temperature …

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Seismic Imaging Of Mantle Transition Zone Discontinuities Beneath The Northern Red Sea And Adjacent Areas, A. A. Mohamed, Stephen S. Gao, A. A. Elsheikh, Kelly H. Liu, Youqiang Yu, R. E. Fat-Helbary Aug 2014

Seismic Imaging Of Mantle Transition Zone Discontinuities Beneath The Northern Red Sea And Adjacent Areas, A. A. Mohamed, Stephen S. Gao, A. A. Elsheikh, Kelly H. Liu, Youqiang Yu, R. E. Fat-Helbary

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The dramatic asymmetry in terms of surface elevation, Cenozoic volcanisms and earthquake activity across the Red Sea is an enigmatic issue in global tectonics, partially due to the unavailability of broad-band seismic data on the African Plate adjacent to the Red Sea. Here, we report the first comprehensive image of the mantle transition zone (MTZ) discontinuities using data from the Egyptian National Seismic Network, and compare the resulting depths of the 410 and 660-km discontinuities with those observed on the Arabian side. Our results show that when a standard earth model is used for time-to-depth conversion, the resulting depth of …

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Theoretical/Experimental Comparison Of Deep Tunneling Decay Of Quasi-Bound H(D)Oco To H(D) + Co₂, Albert F. Wagner, Richard Dawes, Robert Continetti, Hua Guo Aug 2014

Theoretical/Experimental Comparison Of Deep Tunneling Decay Of Quasi-Bound H(D)Oco To H(D) + Co₂, Albert F. Wagner, Richard Dawes, Robert Continetti, Hua Guo

Chemistry Faculty Research & Creative Works

The measured H(D)OCO survival fractions of the photoelectron-photofragment coincidence experiments by the Continetti group are qualitatively reproduced by tunneling calculations to H(D) + CO2 on several recent ab initio potential energy surfaces for the HOCO system. the tunneling calculations involve effective one-dimensional barriers based on steepest descent paths computed on each potential energy surface. the resulting tunneling probabilities are converted into H(D)OCO survival fractions using a model developed by the Continetti group in which every oscillation of the H(D)-OCO stretch provides an opportunity to tunnel. Four different potential energy surfaces are examined with the best qualitative agreement with experiment …

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Fine-Structure Constant For Gravitational And Scalar Interactions, Ulrich D. Jentschura Aug 2014

Fine-Structure Constant For Gravitational And Scalar Interactions, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

Starting from the coupling of a relativistic quantum particle to the curved Schwarzschild space time, we show that the Dirac-Schwarzschild problem has bound states and calculate their energies including relativistic corrections. Relativistic effects are shown to be suppressed by the gravitational fine-structure constant αG=Gm1m2/(ℏc), where G is Newton's gravitational constant, c is the speed of light, and m1 and m2 ≫ m1 are the masses of the two particles. The kinetic corrections due to space-time curvature are shown to lift the familiar (n,j) degeneracy of the energy levels of …

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First-Principles Study Of 180⁰ Domain Walls In Batio₃: Mixed Bloch-Néel-Ising Character, Menglei Li, Yijia Gu, Yi Wang, Long-Qing Chen, Wenhui Duan Aug 2014

First-Principles Study Of 180⁰ Domain Walls In Batio₃: Mixed Bloch-Néel-Ising Character, Menglei Li, Yijia Gu, Yi Wang, Long-Qing Chen, Wenhui Duan

Materials Science and Engineering Faculty Research & Creative Works

The 180⁰ ferroelectric domain walls (FDWs) have long been regarded as purely Ising type in ferroelectrics, but recent theoretical works suggested that they can also have Néel- and/or Bloch-like rotations. Using a combination of first-principles calculations with phase-field simulations, we studied the 180⁰ FDWs on different crystallographic planes in prototypical ferroelectric perovskite BaTiO3. The polarization profiles of 180 FDWs on (100) and (410) planes revealed that the (100)- and (410)-FDWs both exhibit Néel-like character besides their intrinsic Ising character, while the (410)-FDW also simultaneously shows a Bloch-like oblique of ~6 nm, as a consequence of the deviation of …

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Fall 2014 E-Certi Newsletter, Center For Educational Research And Teaching Innovation Aug 2014

Fall 2014 E-Certi Newsletter, Center For Educational Research And Teaching Innovation

CAFE Faculty Newsletters

Hello S&T Instructors -- Welcome back to campus and a busy fall semester. In addition to new structures on the landscape, there are many new faces with dozens of new faculty arriving as well as a new provost and two vice provosts and deans. Read about a recent interview with Drs. Ferguson and Roberts as well as discover interesting facts about some award-winning colleagues.

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Peptide Bond Formation Via Glycine Condensation In The Gas Phase, Eric Van Dornshuld, Robert A. Vergenz, Gregory S. Tschumper Jul 2014

Peptide Bond Formation Via Glycine Condensation In The Gas Phase, Eric Van Dornshuld, Robert A. Vergenz, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

Four unique gas phase mechanisms for peptide bond formation between two glycine molecules have been mapped out with quantum mechanical electronic structure methods. Both concerted and stepwise mechanisms, each leading to a cis and trans glycylglycine product (four mechanisms total), were examined with the B3LYP and MP2 methods and Gaussian atomic orbital basis sets as large as aug-cc-pVTZ. Electronic energies of the stationary points along the reaction pathways were also computed with explicitly correlated MP2-F12 and CCSD(T)-F12 methods. The CCSD(T)-F12 computations indicate that the electronic barriers to peptide bond formation are similar for all four mechanisms (ca. 32-39 kcal mol-1 …

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Comparison Of Synthetic Aperture Radar And Impact-Echo Imaging For Detecting Delamination In Concrete, John S. Popovics, Suyun Ham, Mohammad Tayeb Ahmad Ghasr, R. Zoughi Jul 2014

Comparison Of Synthetic Aperture Radar And Impact-Echo Imaging For Detecting Delamination In Concrete, John S. Popovics, Suyun Ham, Mohammad Tayeb Ahmad Ghasr, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper we evaluate the utility of microwave and mechanical wave nondestructive testing techniques to detect delamination in reinforced concrete bridge deck mock-up samples. The mechanical wave tests comprise air-coupled impact-echo measurements, while the microwave measurements comprise three-dimensional synthetic aperture radar imaging using wideband reflectometery in the frequency range of 1-4 GHz. The results of these investigations are presented in terms of images that are generated from these data. Based on a comparison of the results, we show that the two methods are complementary, in that provide distinct capabilities for defect detection. More specifically, the former approach is unable …

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Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal Jul 2014

Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal

Materials Science and Engineering Faculty Research & Creative Works

Human induced pluripotent stem cells (hiPSCs) can differentiate into notochordal cell (NC)-like cells when cultured in the presence of natural porcine nucleus pulposus (NP) tissue matrix. The method promises massive production of high-quality, functional cells to treat degenerative intervertebral discs (IVDs). Based on our previous work, we further examined the effect of cell-NP matrix contact and culture medium on the differentiation, and further assessed the functional differentiation ability of the generated NC-like. The study showed that direct contact between hiPSCs and NP matrix can promote the differentiation yield, whilst both the contact and non-contact cultures can generate functional NC-like cells. …

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Mechanistic Models Of Biofilm Growth In Porous Media, Priyank Jaiswal, K. Fathiya Al-Hadrami, Estella A. Atekwana, Eliot A. Atekwana Jul 2014

Mechanistic Models Of Biofilm Growth In Porous Media, Priyank Jaiswal, K. Fathiya Al-Hadrami, Estella A. Atekwana, Eliot A. Atekwana

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Nondestructive acoustics methods can be used to monitor in situ biofilm growth in porous media. In practice, however, acoustic methods remain underutilized due to the lack of models that can translate acoustic data into rock properties in the context of biofilm. In this paper we present mechanistic models of biofilm growth in porous media. The models are used to quantitatively interpret arrival times and amplitudes recorded in the 29 day long Davis et al. (2010) physical scale biostimulation experiment in terms of biofilm morphologies and saturation. The model pivots on addressing the sediment elastic behavior using the lower Hashin-Shtrikman bounds …

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Control Of Light Diffusion In A Disordered Photonic Waveguide, Raktim Sarma, Timofey Golubev, Alexey Yamilov, Hui Cao Jul 2014

Control Of Light Diffusion In A Disordered Photonic Waveguide, Raktim Sarma, Timofey Golubev, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

We control the diffusion of light in a disordered photonic waveguide by modulating the waveguide geometry. In a single waveguide of varying cross-section, the diffusion coefficient changes spatially in two dimensions due to localization effects. The intensity distribution inside the waveguide agrees with the prediction of the self-consistent theory of localization. Our work shows that wave diffusion can be efficiently manipulated without modifying the structural disorder.

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Rare Regions And Griffiths Singularities At A Clean Critical Point: The Five-Dimensional Disordered Contact Process, Thomas Vojta, John Igo, José A. Hoyos Jul 2014

Rare Regions And Griffiths Singularities At A Clean Critical Point: The Five-Dimensional Disordered Contact Process, Thomas Vojta, John Igo, José A. Hoyos

Physics Faculty Research & Creative Works

We investigate the nonequilibrium phase transition of the disordered contact process in five space dimensions by means of optimal fluctuation theory and Monte Carlo simulations. We find that the critical behavior is of mean-field type, i.e., identical to that of the clean five-dimensional contact process. It is accompanied by off-critical power-law Griffiths singularities whose dynamical exponent z' saturates at a finite value as the transition is approached. These findings resolve the apparent contradiction between the Harris criterion, which implies that weak disorder is renormalization-group irrelevant, and the rare-region classification, which predicts unconventional behavior. We confirm and illustrate our theory by …

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Theoretical And Experimental Investigation Of (E, 2e) Ionization Of Argon 3p In Asymmetric Kinematics At Intermediate Energy, Sadek Amami, Melike Ulu, Zehra Nur Ozer, Murat Yavuz, Suay Kazgoz, Mevlut Dogan, Oleg Zatsarinny, Klaus Bartschat, Don H. Madison Jul 2014

Theoretical And Experimental Investigation Of (E, 2e) Ionization Of Argon 3p In Asymmetric Kinematics At Intermediate Energy, Sadek Amami, Melike Ulu, Zehra Nur Ozer, Murat Yavuz, Suay Kazgoz, Mevlut Dogan, Oleg Zatsarinny, Klaus Bartschat, Don H. Madison

Physics Faculty Research & Creative Works

The field of electron-impact ionization of atoms, or (e, 2e), has provided significant detailed information about the physics of collisions. For ionization of hydrogen and helium, essentially exact numerical methods have been developed which can correctly predict what will happen. For larger atoms, we do not have theories of comparable accuracy. Considerable attention has been given to ionization of inert gases and, of the inert gases, argon seems to be the most difficult target for theory. There have been several studies comparing experiment and perturbative theoretical approaches over the last few decades, and generally qualitative but not quantitative agreement is …

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The Many Faces Of Garner Interference, Devin Michael Burns Jul 2014

The Many Faces Of Garner Interference, Devin Michael Burns

Psychological Science Faculty Research & Creative Works

A series of speeded classification tasks proposed by Garner (1974) has become a well-entrenched method for identifying interactions between perceptual dimensions. The theory proposes that integral dimensions should produce a redundancy gain when a second dimension covaries perfectly with the attended dimension, and interference if the second dimension varies irrelevantly. This work questions the interpretation of such results as indicating interactive dimensions, reviewing independent models which naturally exhibit such effects. Furthermore, there are several methodological confounds which make the cause of Garner interference non-identifiable in the standard experimental context, the most serious of which is the conflation of changes in …

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