cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Statistical Guarantees for Three Unconventional Estimators
Creators: name: Yi, Yufei
Publisher: name: Carnegie Mellon University
Year: 2021
Subjects: subject: Statistics
subject: FOS: Mathematics

description: In this thesis I consider three unconventional estimators and augment them with statistical guarantees. First, I consider a cone projected power iteration algorithm designed to recover the first principal eigenvector from a noisy positive semidefinite matrix. When the true principal eigenvector is assumed to belong to a convex cone, the proposed algorithm is fast and has a tractable error. Specifically, the method achieves polynomial time complexity for certainconvex cones equipped with fast projection such as the monotone cone. It attains a small error when the noisy matrix has a small cone-restricted operator norm. The above results are supplemented with a minimax lower bound of the error under the spiked covariance model. Numerical experiments on simulated and real data, show that the proposed method achieves shorter run time and smaller error in comparison to the ordinary power iterationand some sparse principal component analysis algorithms if the principal eigenvector is in a convex cone. Second, I develop an abstract procedure for debiasing constrained or regularized potentially high-dimensional linear models. The proposed procedure can produce 1/n-confidence
{\displaystyle {\sqrt {~^{~}}}}intervals for individual coordinates (or even bounded contrasts) in models with unknown covariance, provided that the covariance has bounded spectrum. Examples where theproposed algorithm can be implemented in practice are given. One fairly general class of instances which are amenable to applications of the procedure include convex constrained least squares. I translate the procedure to an abstract algorithm over this class of models, and we give concrete examples where efficient polynomial time methods for debiasing exist. Those include the constrained version of LASSO, regression under monotone constraints,regression with positive monotone constraints and non-negative least squares. In addition, the proposed abstract procedure can be applied to efficiently debias SLOPE and square-root SLOPE, among other popular regularized procedures under certain assumptions. Thoroughsimulation results are provided in support of theoretical findings. Finally, I derive finite sample guarantees for the Chebyshev aka `1 estimator in linear regression, when the noise is known to be uniformly distributed. With a mild assumption on the design matrix, the error rate would be Q(p)=n where Q(p) is a polynomial of the dimension p. In addition, I extend the Chebyshev estimator to high-dimensional settings by incorporating an l1 penalty, and provide convergence guarantees of such an estimator. The high-dimensional Chebyshev estimator achieves a faster rate than the usual l1 penalized least squares estimator, under uniformly distributed noise and sparsity of the signal vector.
Information Transmission using the Nonlinear Fourier Transform, Part I: Mathematical Tools
Creators: name: Yousefi, Mansoor I.
name: Kschischang, Frank R.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: The nonlinear Fourier transform (NFT), a powerful tool in soliton theory and exactly solvable models, is a method for solving integrable partial differential equations governing wave propagation in certain nonlinear media. The NFT decorrelates signal degrees-of-freedom in such models, in much the same way that the Fourier transform does for linear systems. In this three-part series of papers, this observation is exploited for data transmission over integrable channels such as optical fibers, where pulse propagation is governed by the nonlinear Schrödinger equation. In this transmission scheme, which can be viewed as a nonlinear analogue of orthogonal frequency-division multiplexing commonly used in linear channels, information is encoded in the nonlinear frequencies and their spectral amplitudes. Unlike most other fiber-optic transmission schemes, this technique deals with both dispersion and nonlinearity directly and unconditionally without the need for dispersion or nonlinearity compensation methods. This first paper explains the mathematical tools that underlie the method.
description: This version contains minor updates of IEEE Transactions on Information Theory, vol. 60, no. 7, pp. 4312--4328, July 2014
Improving American Civilian Cyber Defense - A Series
Creators: name: Fischer, Sebastian
Publisher: name: Carnegie Mellon University
Year: 2021
Subjects: subject: 89999 Information and Computing Sciences not elsewhere classified
subject: FOS: Computer and information sciences

description: The modern Internet has wrought tremendous changes in the world; allowing individuals to connect easily across continents, business to be conducted in innovative ways, and for nearly instantaneous access to formerly unimaginable stores of information. With all of the changes,the Internet has also altered the landscape of risk – allowing for new opportunities and exposing individuals and groups to novel threats. The world has been quick to adopt the Internet and its attendant technologies but has not always considered what steps would be necessary to preventor even mitigate these new threats. While there were previously warning signs, the past few years have highlighted the dangers individuals, and society at large, face if we continue to fail toaddress these threats.
Testing for Associations between Loci and Environmental Gradients Using Latent Factor Mixed Models
Creators: name: Frichot, Eric
name: Schoville, Sean
name: Bouchard, Guillaume
name: François, Olivier
Publisher: name: arXiv
Year: 2012
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Computation (stat.CO)
subject: FOS: Biological sciences
subject: FOS: Computer and information sciences

description: Adaptation to local environments often occurs through natural selection acting on a large number of loci, each having a weak phenotypic effect. One way to detect these loci is to identify genetic polymorphisms that exhibit high correlation with environmental variables used as proxies for ecological pressures. Here, we propose new algorithms based on population genetics, ecological modeling, and statistical learning techniques to screen genomes for signatures of local adaptation. Implemented in the computer program "latent factor mixed model" (LFMM), these algorithms employ an approach in which population structure is introduced using unobserved variables. These fast and computationally efficient algorithms detect correlations between environmental and genetic variation while simultaneously inferring background levels of population structure. Comparing these new algorithms with related methods provides evidence that LFMM can efficiently estimate random effects due to population history and isolation-by-distance patterns when computing gene-environment correlations, and decrease the number of false-positive associations in genome scans. We then apply these models to plant and human genetic data, identifying several genes with functions related to development that exhibit strong correlations with climatic gradients.
description: 29 pages with 8 pages of Supplementary Material (V2 revised presentation and results part)
Network Global Testing and Estimating Number of Network Communities
Creators: name: Luo, Shengming
Publisher: name: Carnegie Mellon University
Year: 2021
Subjects: subject: 10405 Statistical Theory
subject: FOS: Mathematics

description: Given a symmetrical social network, the network global testing is where we use the adjacency matrix of the network to test whether it has only one community or multiplecommunities. It's also naturally connected to the problem of estimating the number of network communities, which is arguably one of the most important problem in networkanalysis area. Despite many interesting works in recent years, it remains unclear how to find test statistics and estimators that are (a) applicable to networks with severe degree heterogeneity and mixed-memberships with varying sparsity, and is (b) optimal. This thesis aims to design statistics to solve the above two problems, under a more realistic network model. To assess optimality, we use the phase transition framework, which includes the standard minimax argument, but is more informative.
Tail asymptotics for cumulative processes sampled at heavy-tailed random times with applications to queueing models in Markovian environments
Creators: name: Masuyama, Hiroyuki
Publisher: name: arXiv
Year: 2012
Subjects: subject: Probability (math.PR)
subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 60G50, 60F10, 60K25

description: This paper considers the tail asymptotics for a cumulative process $\{B(t); t \ge 0\}$ sampled at a heavy-tailed random time $T$. The main contribution of this paper is to establish several sufficient conditions for the asymptotic equality ${\sf P}(B(T) > bx) \sim {\sf P}(M(T) > bx) \sim {\sf P}(T>x)$ as $x \to \infty$, where $M(t) = \sup_{0 \le u \le t}B(u)$ and $b$ is a certain positive constant. The main results of this paper can be used to obtain the subexponential asymptotics for various queueing models in Markovian environments. As an example, using the main results, we derive subexponential asymptotic formulas for the loss probability of a single-server finite-buffer queue with an on/off arrival process in a Markovian environment.
On Building Robustness into Compilation-Based Main-Memory Database Query Engines
Creators: name: Menon, Prashanth
Publisher: name: Carnegie Mellon University
Year: 2021
Subjects: Applied Computer Science

description: Relational database management systems (DBMS) are the bedrock upon which modern data processing intensive applications are assembled. Critical to ensuring low-latency queries is the efficiency of the DBMSs query processor. Just-in-time (JIT) query compilation is a popular techniqueto improve analytical query processing performance. However, a compiled query cannot overcome poor choices made by the DBMSs optimizer. A lousy query plan results in lousy query code. Poor query plans often arise and for many reasons. Although there is a large body of work exploring how a query processor can adapt itself at runtime to compensate for inadequate plans, these techniques do not work in DBMSs that rely on compiling queries. This dissertation presents multiple effective, practical, and complementary techniques to build adaptive query processing into compilation-based engines with negligible overhead. First, we propose a method that intelligently blends two otherwise disparate query processing approaches (compilation and vectorization) into one engine. This necessary first step allows operators to optimizethemselves using a combination of software memory prefetching and single instruction, multiple data (SIMD) vectorization resulting in improved performance. Next, we present a framework that builds upon our previous work to allow the DBMS to modify compiled queries without recompiling the plan or generating code speculatively. This technique enables more extensive groups of operators in a query to coordinate their optimization process. Finally, we present a method that decomposes query plans into fragments that can be compiled and executed independently. This not only reduces compilation overhead but enables the DBMS to learn properties about data processed in an earlier phase of the query to hyper-optimize the code it generates for later phases. Collectively, the techniques proposed in this dissertation enable any compilation-based DBMS to achieve dynamic runtime robustness without succumbing to any of its overheads.
Isogeometric analysis: an overview and computer implementation aspects
Creators: name: Nguyen, Vinh Phu
name: Bordas, Stéphane P. A.
name: Rabczuk, Timon
Publisher: name: arXiv
Year: 2012
Subjects: subject: Numerical Analysis (math.NA)
subject: Mathematical Software (cs.MS)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Isogeometric analysis (IGA) represents a recently developed technology in computational mechanics that offers the possibility of integrating methods for analysis and Computer Aided Design (CAD) into a single, unified process. The implications to practical engineering design scenarios are profound, since the time taken from design to analysis is greatly reduced, leading to dramatic gains in efficiency. The tight coupling of CAD and analysis within IGA requires knowledge from both fields and it is one of the goals of the present paper to outline much of the commonly used notation. In this manuscript, through a clear and simple Matlab implementation, we present an introduction to IGA applied to the Finite Element (FE) method and related computer implementation aspects. Furthermore, implemen- tation of the extended IGA which incorporates enrichment functions through the partition of unity method (PUM) is also presented, where several examples for both two-dimensional and three-dimensional fracture are illustrated. The open source Matlab code which accompanies the present paper can be applied to one, two and three-dimensional problems for linear elasticity, linear elastic fracture mechanics, structural mechanics (beams/plates/shells including large displacements and rotations) and Poisson problems with or without enrichment. The Bezier extraction concept that allows FE analysis to be performed efficiently on T-spline geometries is also incorporated. The article includes a summary of recent trends and developments within the field of IGA.
Holistic approach for microgrid planning and operation for e-mobility infrastructure under consideration of multi-type uncertainties
Creators: name: Tayyab, Muhammad
Publisher: name: Otto-von-Guericke-Universität Magdeburg, Magdeburg
Year: 2022
Subjects: subject: Energie
subject: e-mobility
subject: Infrastructure
subject: Microgrid planning and operation
subject: 621.31

description: Integrating renewable energys ources in sectors such as electricity, heat, and transportation must be structured in an economic, technological, and emission- efficient manner to address global environmental issues.Microgrids appear to be the solution for large-scale renewable energy integration in these sectors.The microgrid components must be optimally planned and operated to prevent high costs, technical issues, and emissions. Existing approaches for optimal microgrid planning and operation in the literature do not include a solution for e-mobility infrastructure. As a consequence, a compact e-mobility infrastructure metho- dology is provided.The development of e-mobility infrastructure has as sociated uncertainties (short and long-term). As a result, a new stochastic method re- ferred to as IGDM-DRO is proposed in this dissertation.The proposed method provides a risk-averse strategy for microgrid planning and operation by including long-term and short-term uncertainty related to e-mobility.The multi-cut ben- der decomposition is applied for IGDM-DRO to prevent the suggested method’s intractability.Finally, the deterministic and stochastic methodologies are com bined in an ovelholistic approach for microgrid design and operation in terms of cost and robustness.The proposed method ist ested on a new settlement area in Magdeburg, Germany, under three different EV development scenarios (nega- tive, trend, andpositive).The share for the number of electric vehicles reached 31 percent of conventional vehicles by the end of the planned horizon. As a result, the microgrid’s overall cost has been increased by 2.3 to 2.9 percent per electric vehicle.Three public electric vehicle charging stations will be required in the investigated settlement are a intrend 2031.The investigated settlement area will require a total cost of 127,029 € in the trend scenario.To achieve full robustness against long-term uncertainties,the cost of the microgrid needs to be increased by 80 percent.
Bootstrap Prediction Bands for Functional Time Series
Creators: name: Paparoditis, Efstathios
name: Shang, Han Lin
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Space Science
subject: Medicine
subject: Molecular Biology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics

description: A bootstrap procedure for constructing prediction bands for a stationary functional time series is proposed. The procedure exploits a general vector autoregressive representation of the time-reversed series of Fourier coefficients appearing in the Karhunen–Loève representation of the functional process. It generates backward-in-time functional replicates that adequately mimic the dependence structure of the underlying process in a model-free way and have the same conditionally fixed curves at the end of each functional pseudo-time series. The bootstrap prediction error distribution is then calculated as the difference between the model-free, bootstrap-generated future functional observations and the functional forecasts obtained from the model used for prediction. This allows the estimated prediction error distribution to account for the innovation and estimation errors associated with prediction and the possible errors due to model misspecification. We establish the asymptotic validity of the bootstrap procedure in estimating the conditional prediction error distribution of interest, and we also show that the procedure enables the construction of prediction bands that achieve (asymptotically) the desired coverage. Prediction bands based on a consistent estimation of the conditional distribution of the studentized prediction error process also are introduced. Such bands allow for taking more appropriately into account the local uncertainty of the prediction. Through a simulation study and the analysis of two datasets, we demonstrate the capabilities and the good finite-sample performance of the proposed method.
On the evaluation of modular polynomials
Creators: name: Sutherland, Andrew V.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Number Theory (math.NT)
subject: Cryptography and Security (cs.CR)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 11G07 (Primary) 11Y16, 14H52, 11G15 (Secondary)

description: We present two algorithms that, given a prime ell and an elliptic curve E/Fq, directly compute the polynomial Phi_ell(j(E),Y) in Fq[Y] whose roots are the j-invariants of the elliptic curves that are ell-isogenous to E. We do not assume that the modular polynomial Phi_ell(X,Y) is given. The algorithms may be adapted to handle other types of modular polynomials, and we consider applications to point counting and the computation of endomorphism rings. We demonstrate the practical efficiency of the algorithms by setting a new point-counting record, modulo a prime q with more than 5,000 decimal digits, and by evaluating a modular polynomial of level ell = 100,019.
description: 19 pages, corrected a typo in equation (8) and added equation (9)
Compulsive hoarding and the theory of value : an economic model of excessive accumulation
Creators: name: Welsted, Alison C.
Publisher: name: University of British Columbia
Year: 2014

description: Hoarding disorder is a complex form of psychopathology that is characterized by excessive accumulation of items and extreme difficulty parting with possessions. It affects 2% to 6% of the population and is associated with significant distress, impairment, and cost to affected individuals, their family and friends, and society. Hoarding disorder is a new diagnosis. Theoretical models and treatment protocols are, therefore, emergent. Valuing of items is notably abnormal in hoarding disorder and the theory of value from economics provides a suitable framework for examining this phenomenon. Individuals with hoarding disorder accumulate a much larger number of items than do most people, and many of those items are objectively worthless. Revealed preference suggests that excessive accumulation of items can be explained by overvaluation of items relative to other goods. Also, in hoarding, often multiple units of the same item are kept when one would suffice. This could be explained by attenuated diminishing marginal value. Finally, hoarding is associated with extreme difficulty parting with possessions, which is consistent with an enhanced endowment effect. The current research assembles the phenomena of abnormal valuing into a coherent theoretical model and conducts initial empirical investigations to test predictions from the theory. Valuing of everyday household items, diminishing marginal value, and the endowment effect were examined among 128 participants: 43 with hoarding disorder, 46 with subclinical levels of hoarding symptoms, and 36 healthy controls. Participants attended one lab session and completed a clinical interview, computer-based questionnaires, and three valuing tasks. Data were analysed using ANOVA and regression models. Hoarding symptoms and cognitions were both positive predictors of the number of no-cost and sentimental items that participants attributed with some value. Hoarding was a unique predictor of attributing value to sentimental items, whereas, hoarding was confounded with other aspects of psychopathology in predicting valuing of no-cost items. These results suggest that individuals with hoarding disorder are particularly adept at finding value in items that others would consider to be worthless. This could be an important focus for treatment. Avenues for future research are suggested in the areas of hoarding disorder, behavioural economics, and item ownership.
Bootstrap prediction bands for functional time series
Creators: name: Paparoditis, Efstathios
name: Shang, Han Lin
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Space Science
subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics

description: A bootstrap procedure for constructing prediction bands for a stationary functional time series is proposed. The procedure exploits a general vector autoregressive representation of the time-reversed series of Fourier coefficients appearing in the Karhunen-Loève representation of the functional process. It generates backward-in-time functional replicates that adequately mimic the dependence structure of the underlying process in a model-free way and have the same conditionally fixed curves at the end of each functional pseudo-time series. The bootstrap prediction error distribution is then calculated as the difference between the model-free, bootstrap-generated future functional observations and the functional forecasts obtained from the model used for prediction. This allows the estimated prediction error distribution to account for the innovation and estimation errors associated with prediction and the possible errors due to model misspecification. We establish the asymptotic validity of the bootstrap procedure in estimating the conditional prediction error distribution of interest, and we also show that the procedure enables the construction of prediction bands that achieve (asymptotically) the desired coverage. Prediction bands based on a consistent estimation of the conditional distribution of the studentized prediction error process also are introduced. Such bands allow for taking more appropriately into account the local uncertainty of the prediction. Through a simulation study and the analysis of two data sets, we demonstrate the capabilities and the good finite-sample performance of the proposed method.
How Good a Clock is Rotation? The Stellar Rotation-Mass-Age Relationship for Old Field Stars
Creators: name: Epstein, Courtney R.
name: Pinsonneault, Marc H.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The rotation-mass-age relationship offers a promising avenue for measuring the ages of field stars, assuming the attendant uncertainties to this technique can be well characterized. We model stellar angular momentum evolution starting with a rotation distribution from open cluster M37. Our predicted rotation-mass-age relationship shows significant zero-point offsets compared to an alternative angular momentum loss law and published gyrochronology relations. Systematic errors at the 30 percent level are permitted by current data, highlighting the need for empirical guidance. We identify two fundamental sources of uncertainty that limit the precision of rotation-based ages and quantify their impact. Stars are born with a range of rotation rates, which leads to an age range at fixed rotation period. We find that the inherent ambiguity from the initial conditions is important for all young stars, and remains large for old stars below 0.6 solar masses. Latitudinal surface differential rotation also introduces a minimum uncertainty into rotation period measurements and, by extension, rotation-based ages. Both models and the data from binary star systems 61 Cyg and alpha Cen demonstrate that latitudinal differential rotation is the limiting factor for rotation-based age precision among old field stars, inducing uncertainties at the ~2 Gyr level. We also examine the relationship between variability amplitude, rotation period, and age. Existing ground-based surveys can detect field populations with ages as old as 1-2 Gyr, while space missions can detect stars as old as the Galactic disk. In comparison with other techniques for measuring the ages of lower main sequence stars, including geometric parallax and asteroseismology, rotation-based ages have the potential to be the most precise chronometer for 0.6-1.0 solar mass stars.
description: For a brief video explaining the key results of this paper, see http://www.youtube.com/user/OSUAstronomy
A setting for higher order differential equations fields and higher order Lagrange and Finsler spaces
Creators: name: Bucataru, Ioan
Publisher: name: arXiv
Year: 2012
Subjects: subject: Differential Geometry (math.DG)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 34A26, 53C60, 70H03, 70H50

description: We use the Frölicher-Nijenhuis formalism to reformulate the inverse problem of the calculus of variations for a system of differential equations of order 2k in terms of a semi-basic 1-form of order k. Within this general context, we use the homogeneity proposed by Crampin and Saunders in [14] to formulate and discuss the projective metrizability problem for higher order differential equation fields. We provide necessary and sufficient conditions for higher order projectivpre-e metrizability in terms of homogeneous semi-basic 1-forms. Such a semi-basic 1-form is the Poincaré-Cartan 1-form of a higher order Finsler function, while the potential of such semi-basic 1-form is a higher order Finsler function.
description: final, pre-published version
Entanglement evolution of three-qubit mixed states in multipartite cavity-reservoir systems
Creators: name: Xu, Jing-Zhou
name: Guo, Jin-Bao
name: Wen, Wei
name: Bai, Yan-Kui
name: Yan, Fengli
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We analyze the multipartite entanglement evolution of three-qubit mixed states composed of a GHZ state and a W state. For a composite system consisting of three cavities interacting with independent reservoirs, it is shown that the entanglement evolution is restricted by a set of monogamy relations. Furthermore, as quantified by the negativity, the entanglement dynamical property of the mixed entangled state of cavity photons is investigated. It is found that the three cavity photons can exhibit the phenomenon of entanglement sudden death (ESD). However, compared with the evolution of a generalized three-qubit GHZ state which has the equal initial entanglement, the ESD time of mixed states is later than that of the pure state. Finally, we discuss the entanglement distribution in the multipartite system, and point out the intrinsic relation between the ESD of cavity photons and the entanglement sudden birth of reservoirs.
description: 6 pages, 3 figures
On occult period maps
Creators: name: Kudla, Stephen
name: Rapoport, Michael
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: We consider the "occult" period maps into ball quotients which exist for the moduli spaces of cubic surfaces, cubic threefolds, non-hyperelliptic curves of genus three and four. These were constructed in the work of Allcock/Carlson/Toledo, Looijenga/Swierstra, and Kondo. We interpret these maps as morphisms into moduli spaces of polarized abelian varieties of Picard type, and show that these morphisms, whose initial construction is transcendental, are defined over the natural field of definition of the spaces involved. This paper is extracted from section 15 of our paper arXiv:0912.3758, and differs from it only in some points of exposition.
description: This version includes a minor correction of a stack issue and now matches the published version
Select Northern Nigeria’s FM Radio Programs on the Scale of Representation of Local Culture: Comparative Analysis
Creators: name: Yusuf-Hamdani, Muhammad Kabir
Publisher: name: figshare
Year: 2021
Subjects: subject: 200199 Communication and Media Studies not elsewhere classified
subject: FOS: Media and communications

description: Yusuf, M. K. (2021), Select Northern Nigeria’s FM Radio Programs on the Scale of Representation of Local Culture: Comparative Analysis, Issues in Mass Media and National Security, a publication of the department of Mass Communication, Kaduna State University, Nigeria
Controllable operation for distant qubits in a two-dimensional quantum network
Creators: name: Zhong, Z. -R.
name: Lin, X.
name: Zhang, B.
name: Yang, Z. -B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a theoretical scheme to realize the coherent coupling of multiple atoms in a quantum network which is composed of a two-dimensional (2D) array of coupled cavities. In the scheme, the pairing off-resonant Raman transitions of different atoms, induced by the cavity modes and external fields, can lead to selective coupling between arbitrary atoms trapped in separated cavities. Based on this physical mechanism, quantum gates between any pair of qubits and parallel two-qubit operations can be performed in the 2D system. The scheme provides a new perspective for coherent manipulation of quantum systems in 2D quantum networks.
description: 6 pages,4 figures
Beyond Socialising: Blogging as a teaching aid for Mass Communication writings Classes
Creators: name: Yusuf-Hamdani, Muhammad Kabir
Publisher: name: figshare
Year: 2021
Subjects: subject: 200102 Communication Technology and Digital Media Studies
subject: FOS: Media and communications

description: Yusuf, M. K. (2021), Beyond Socialising: Blogging as a teaching aid for Mass Communication writings Classes, Academia Letters, https://www.academia.edu/letters/submission 
Kamerabasierte Messung von Vitalparametern mit verbesserter Störsicherheit
Creators: name: Rapczy´Nski, Michał
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: Medizintechnik
subject: Vitalparameter
subject: Signalverarbeitung
subject: 621.369

description: Die kontaktfreie, kamerabasierte Messung von Vitalparameter des Menschen bietet diverse Vorteile gegen über klassischen kontaktbasierten Methoden. Verfahren aus dem Stand der Technik haben jedoch verschiedene Probleme in realistischen Anwendungsszenarien. So verursachen Bewegungen oder Verdeckungen, zum Beispiel durch Haare oder Brillen, Störsignale, welche die Messgenauigkeit einschränken. In dieser Arbeit werden unterschiedliche Ansätze zur Verbesserung der Störsicherheit für die Messung verschiedener Vitalparameter vorgestellt. Dabei werden alle Teile der Signalverarbeitungskette betrachtet. Neue Methoden für die Wahl der Region of Interest, Signalverarbeitung und Korrekturverfahren werden vorgestellt. Zudem wurden grundlegende Untersuchungen des Einflusses der Videokompression auf die Genauigkeit und die Messung der Vitalparameter in einem breiten Spektrum im Nahinfrarotbereich, durchgeführt. Die kontaktlose Vitalparametermessung wurde zudem in zwei Anwendungsfällen validiert, der Lebenderkennung und der Messung der Vitalparameter in einem MRT. Die Messgenauigkeit und Störsicherheit konnte durch die vorgestellten Methoden deutlich verbessert und neue Ansätze für die zukünftige Nutzung der Technologie erschlossen werden.
description: The non-contact, camera-based measurement of human vital signs offers various advantages over classical contact-based methods. However, stateof- the-art methods have various problems in realistic application scenarios. For example, movements or occlusions, e.g. by hair or glasses, cause interfering signals that limit the measurement accuracy. In this work, different approaches to improve the noise robustness for the measurement of different vital signs are presented. All parts of the signal processing chain are considered. New methods for region of interest selection, signal processing and correction techniques are presented. In addition, fundamental studies of the influence of video compression on the accuracy, and measurement of vital signs in a wide spectrum in the near-infrared range, have been carried out. The non-contact vital sign measurement was also validated in two use cases, life detection and vital sign measurement in an MRI. The measurement accuracy and noise immunity could be significantly improved by the presented methods and new approaches for the future use of the technology could be developed.
Higgs mass and vacuum stability in the Standard Model at NNLO
Creators: name: Degrassi, Giuseppe
name: Di Vita, Stefano
name: Elias-Miró, Joan
name: Espinosa, José R.
name: Giudice, Gian F.
name: Isidori, Gino
name: Strumia, Alessandro
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present the first complete next-to-next-to-leading order analysis of the Standard Model Higgs potential. We computed the two-loop QCD and Yukawa corrections to the relation between the Higgs quartic coupling (lambda) and the Higgs mass (Mh), reducing the theoretical uncertainty in the determination of the critical value of Mh for vacuum stability to 1 GeV. While lambda at the Planck scale is remarkably close to zero, absolute stability of the Higgs potential is excluded at 98% C.L. for Mh < 126 GeV. Possible consequences of the near vanishing of lambda at the Planck scale, including speculations about the role of the Higgs field during inflation, are discussed.
description: 35 pages, 8 figures. Final published version, misprints fixed, figures updated
On the stability of stochastic jump kinetics
Creators: name: Engblom, Stefan
Publisher: name: arXiv
Year: 2012
Subjects: subject: Probability (math.PR)
subject: Numerical Analysis (math.NA)
subject: Molecular Networks (q-bio.MN)
subject: FOS: Mathematics
subject: FOS: Biological sciences
subject: 60J27, 92C42, 60J28, 92C45

description: Motivated by the lack of a suitable constructive framework for analyzing popular stochastic models of Systems Biology, we devise conditions for existence and uniqueness of solutions to certain jump stochastic differential equations (SDEs). Working from simple examples we find reasonable and explicit assumptions on the driving coefficients for the SDE representation to make sense. By `reasonable' we mean that stronger assumptions generally do not hold for systems of practical interest. In particular, we argue against the traditional use of global Lipschitz conditions and certain common growth restrictions. By `explicit', finally, we like to highlight the fact that the various constants occurring among our assumptions all can be determined once the model is fixed. We show how basic long time estimates and some limit results for perturbations can be derived in this setting such that these can be contrasted with the corresponding estimates from deterministic dynamics. The main complication is that the natural path-wise representation is generated by a counting measure with an intensity that depends nonlinearly on the state.
On two-particle Anderson localization at low energies
Creators: name: Ekanga, Trésor
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: Primary 47B80, 47A75. Secondary 35P10

description: We prove exponential spectral localization in a two-particle lattice Anderson model, with a short-range interaction and external random i.i.d. potential, at sufficiently low energies. The proof is based on the multi-particle multi-scale analysis developed earlier by Chulaevsky and Suhov (2009) in the case of high disorder. Our method applies to a larger class of random potentials than in Aizenman and Warzel (2009) where dynamical localization was proved with the help of the fractional moment method.
Carleman estimates for the Zaremba Boundary Condition and Stabilization of Waves
Creators: name: Cornilleau, Pierre
name: Robbiano, Luc
Publisher: name: arXiv
Year: 2011
Subjects: subject: Analysis of PDEs (math.AP)
subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: In this paper, we shall prove a Carleman estimate for the so-called Zaremba problem. Using some techniques of interpolation and spectral estimates, we deduce a result of stabilization for the wave equation by means of a linear Neumann feedback on the boundary. This extends previous results from the literature: indeed, our logarithmic decay result is obtained while the part where the feedback is applied contacts the boundary zone driven by an homogeneous Dirichlet condition. We also derive a controllability result for the heat equation with the Zaremba boundary condition.
description: 37 pages, 3 figures. Final version to be published in Amer. J. Math
Artificial Neural Network based on SQUIDs: demonstration of network training and operation
Creators: name: Chiarello, F.
name: Carelli, P.
name: Castellano, M. G.
name: Torrioli, G.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We propose a scheme for the realization of artificial neural networks based on Superconducting Quantum Interference Devices (SQUIDs). In order to demonstrate the operation of this scheme we designed and successfully tested a small network that implements a XOR gate and is trained by means of examples. The proposed scheme can be particularly convenient as support for superconducting applications such as detectors for astrophysics, high energy experiments, medicine imaging and so on.
description: 10 pages, 6 figures
Measure Preserving Words are Primitive
Creators: name: Puder, Doron
name: Parzanchevski, Ori
Publisher: name: arXiv
Year: 2012
Subjects: subject: Group Theory (math.GR)
subject: Combinatorics (math.CO)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 20E05 (Primary), 20E18, 20B30, 68R15, 06A11 (Secondary)

description: We establish new characterizations of primitive elements and free factors in free groups, which are based on the distributions they induce on finite groups. For every finite group $G$, a word $w$ in the free group on $k$ generators induces a word map from $G^k$ to $G$. We say that $w$ is measure preserving with respect to $G$ if given uniform distribution on $G^k$, the image of this word map distributes uniformly on $G$. It is easy to see that primitive words (words which belong to some basis of the free group) are measure preserving w.r.t. all finite groups, and several authors have conjectured that the two properties are, in fact, equivalent. Here we prove this conjecture. The main ingredients of the proof include random coverings of Stallings graphs, algebraic extensions of free groups, and Möbius inversions. Our methods yield the stronger result that a subgroup of $F_k$ is measure preserving if and only if it is a free factor. As an interesting corollary of this result we resolve a question on the profinite topology of free groups and show that the primitive elements of $F_k$ form a closed set in this topology.
description: 37 pages, 6 figures. The new Prop. 1.6 determines which finite set of finite groups is needed to determine the primitivity of w
Auslegungskriterien hochdynamischer Linearmaschinen für alternierende Bewegungen
Creators: name: Benecke, Sebastian
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: Elektrische Maschinen und Antriebe
subject: Linearmaschinen
subject: 621.46

description: Bei der Auslegung von elektrischen Linearmaschinen kann es eine Herausforderung sein, einen genauen Arbeitspunkt zu definieren, für den die Maschine optimiert werden soll. Vor allem bei Linearaktuatoren mit hochdynamischen Bewegungsverläufen ist es nicht möglich, einen stationären Betriebspunkt für die Optimierung festzulegen, wie es bei konventionellen Auslegungsmethoden etabliert ist. Mit dieser Problemstellung befasst sich die vorliegende Arbeit. Vor dem Hintergrund der Maximierung der Energieeffizienz eines Antriebssystems für periodische Bewegungen wurde dessen Verhalten analytisch Beschrieben und charakteristische Eigenschaften und Zusammenhänge herausgearbeitet. Basierend auf den dabei gefundenen Auslegungskriterien ist ein Optimierungsablauf entwickelt worden, der zum Design einer elektrischen Maschine für einen Freikolbenlineargenerator eingesetzt wurde. Anhand von experimentellen Messungen an dem konstruierten Prototyp konnten die Simulationsschritte verifiziert und die Wirksamkeit der Auslegungskriterien unter Beweis gestellt werden. Damit erreichte diese Forschungsarbeit das Ziel, eine Auslegungsmethodik für elektrische Linearmaschinen zu entwickeln, die ausschlaggebenden allgemeinen Charakteristiken sowohl der Maschine als auch von dynamischen Belastungsverläufen herauszuarbeiten und eine Validierung durchzuführen. Diese Herangehensweise für die Optimierung von Antrieben mit periodischen Bewegungszyklen kann neben den erwähnten Freikolbenmaschinen in anderen direkt angetriebenen Systemen wie Pumpen, Kompressoren oder Wellenkraftwerken Anwendung finden.
description: When designing electrical linear machines, it can be a challenge to define an exact operating point for which the machine is to be optimized. Especially for linear actuators with highly dynamic motion profiles, it is not possible to define a steady-state operating point for optimization, as is done in conventional design methods. This problem is addressed in the present work. With the priority on maximizing the energy efficiency of a drive system for periodic movements, its behavior was described analytically and characteristic properties and relationships were established. Based on the design criteria found in the process, an optimization procedure was developed which was used to design an electric machine for a free-piston linear generator. Experimental measurements on the designed prototype were used to verify the simulation steps and to prove the effectiveness of the design criteria. Thus, this research achieved the goal of developing a design methodology for electrical linear machines, elaborating characteristic criteria and performing a validation in order to present an approach for the optimization of drive systems with highly dynamic, periodic motion cycles.
Experimental simulation of quantum tunneling in small systems
Creators: name: Feng, Guan Ru
name: Lu, Yao
name: Hao, Liang
name: Zhang, Fei Hao
name: Long, Gui Lu
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: It is well known that quantum computers are superior to classical computers in efficiently simulating quantum systems. Here we report the first experimental simulation of quantum tunneling through potential barriers, a widespread phenomenon of a unique quantum nature, via NMR techniques. Our experiment is based on a digital particle simulation algorithm and requires very few spin-1/2 nuclei without the need of ancillary qubits. The occurrence of quantum tunneling through a barrier, together with the oscillation of the state in potential wells, are clearly observed through the experimental results. This experiment has clearly demonstrated the possibility to observe and study profound physical phenomena within even the reach of small quantum computers.
description: 17 pages and 8 figures
Nonlinear instability of solutions in parabolic and hyperbolic diffusion
Creators: name: Pankavich, Stephen
name: Radu, Petronela
Publisher: name: arXiv
Year: 2011
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35L15, 35K15, 35B35, 35B40

description: We consider semilinear evolution equations of the form $a(t)\partial_{tt}u + b(t) \partial_t u + Lu = f(x,u)$ and $b(t) \partial_t u + Lu = f(x,u),$ with possibly unbounded $a(t)$ and possibly sign-changing damping coefficient $b(t)$, and determine precise conditions for which linear instability of the steady state solutions implies nonlinear instability. More specifically, we prove that linear instability with an eigenfunction of fixed sign gives rise to nonlinear instability by either exponential growth or finite-time blow-up. We then discuss a few examples to which our main theorem is immediately applicable, including evolution equations with supercritical and exponential nonlinearities.
description: 20 pages
Langlands Program, Trace Formulas, and their Geometrization
Creators: name: Frenkel, Edward
Publisher: name: arXiv
Year: 2012
Subjects: subject: Representation Theory (math.RT)
subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: The Langlands Program relates Galois representations and automorphic representations of reductive algebraic groups. The trace formula is a powerful tool in the study of this connection and the Langlands Functoriality Conjecture. After giving an introduction to the Langlands Program and its geometric version, which applies to curves over finite fields and over the complex field, I give a survey of my recent joint work with Robert Langlands and Ngo Bao Chau (arXiv:1003.4578 and arXiv:1004.5323) on a new approach to proving the Functoriality Conjecture using the trace formulas, and on the geometrization of the trace formulas. In particular, I discuss the connection of the latter to the categorification of the Langlands correspondence.
description: Notes for the AMS Colloquium Lectures given by the author at the 2012 Joint Mathematics Meetings in Boston, January 4-6, 2012. Version 2: small changes in Sections 5.9 and 6.4
Nigcomsat: Appraising Patterns of intercultural communication beyond the evolution of broadcast in Nigeria
Creators: name: Yusuf-Hamdani, Muhammad Kabir
Publisher: name: figshare
Year: 2021
Subjects: subject: 200101 Communication Studies
subject: FOS: Media and communications
subject: 200199 Communication and Media Studies not elsewhere classified

description: Yusuf, M. K. (2016), Gadau Journal of Arts and Education, Vol. 2, No. 1, Bauchi State University, Gadau, Bauchi State, Nigeria