Two dimensional symmetric and antisymmetric generalizations of sine functions

Properties of 2-dimensional generalizations of sine functions that are symmetric or antisymmetric with respect to permutation of their two variables are described. It is shown that the functions are orthogonal when integrated over a finite region $F$ of the real Euclidean space, and that they are discretely orthogonal when summed up over a lattice of any density in $F$. Decomposability of the products of functions into their sums is shown by explicitly decomposing products of all types. The formalism is set up for Fourier-like expansions of digital data over 2-dimensional lattices in $F$. Continuous interpolation of digital data is studied.Comment: 12 pages, 5 figure

The lifecycle of the North Atlantic storm track

The North Atlantic eddy-driven jet exhibits latitudinal variability, with evidence of three preferred latitudinal locations: south, middle and north. Here we examine the drivers of this variability and the variability of the associated storm track. We investigate the changes in the storm track characteristics for the three jet locations, and propose a mechanism by which enhanced storm track activity, as measured by upstream heat flux, is responsible for cyclical downstream latitudinal shifts in the jet. This mechanism is based on a nonlinear oscillator relationship between the enhanced meridional temperature gradient (and thus baroclinicity) and the meridional high-frequency (periods of shorter than 10 days) eddy heat flux. Such oscillations in baroclinicity and heat flux induce variability in eddy anisotropy which is associated with the changes in the dominant type of wave breaking and a different latitudinal deflection of the jet. Our results suggest that high heat flux is conducive to a northward deflection of the jet, whereas low heat flux is conducive to a more zonal jet. This jet deflecting effect was found to operate most prominently downstream of the storm track maximum, while the storm track and the jet remain anchored at a fixed latitudinal location at the beginning of the storm track. These cyclical changes in storm track characteristics can be viewed as different stages of the storm track’s spatio-temporal lifecycle

Verification of ZVS boost converter with resonant circuit & modelling of an accurate two-diode PV array system simulator using MATLAB simulink

This thesis proposes a MATLAB Simulink simulator for Photo Voltaic (PV) Array system. The main contribution is the utilisation of a Two-Diode model to represent a PV cell. This model is preferred because of its better accuracy at low irradiance levels. A PV of Kyocera (KC200GT) 50*10 Array is taken & the characteristics curves are plotted. The same simulator can be interfaced with MPPT algorithms & Power Electronics converters for better efficiency. The P-V & I-V Curves of this simulator is found in exact with that given by the manufacturers. It is expected that the proposed work can be very useful for PV professionals who require a simple, fast & accurate PV simulator in order to design their systems. A detailed analysis of a resonant circuit based soft-switching boost-converter for PV applications is also performed. The converter operates at Zero Voltage Switching (ZVS) turn-on and turn-off of the main switch, & Zero Current Switching (ZCS) turn-on and ZVS turn-off of the auxiliary switch due to resonant circuit incorporated into the circuit. Detailed operation of the converters, analysis of various modes, simulation as well as experimental results for the design has also been aptly presented. The systems are modelled & simulated in MATLAB 2013a 64-bit version and the output waveforms are shown

Number of arrhythmia beats determination in Holter electrocardiogram: How many clusters?

Holter signals correspond to long-term electrocardiograph (ECG) registers. Manual inspection of such signals is difficult because of the enormous quantity of beats involved. Throughout the literature several methods of automatically detecting and separating the significant beats using unsupervised learning were proposed. An important part of the unsupervised learning problem is determining the number of constituent clusters which best describe the data. In this paper we concentrate on the problem of the number of arrhythmia beats-clusters selection presented in Holter ECG. We apply and compare several criteria for assessing the number of clusters and we show that, with a Gaussian mixture model, the approach is able to select 'an optimal' number of arrhythmia beats and so partition a Holter ECG. The following criteria has been examined: Bayesian selection method, Akaike's information criteria, minimum description length, minimum message length, fuzzy hyper volume, evidence density and partition coefficient. We conclude that only minimum description length and Bayesian selection method are suitable for our real-world electrocardiogram data. In order to validate the procedure, an experimental comparative study is carried out, utilizing records from the MIT database

Characterizing Granular Networks Using Topological Metrics

We carry out a direct comparison of experimental and numerical realizations of the exact same granular system as it undergoes shear jamming. We adjust the numerical methods used to optimally represent the experimental settings and outcomes up to microscopic contact force dynamics. Measures presented here range form microscopic, through mesoscopic to system-wide characteristics of the system. Topological properties of the mesoscopic force networks provide a key link between micro and macro scales. We report two main findings: the number of particles in the packing that have at least two contacts is a good predictor for the mechanical state of the system, regardless of strain history and packing density. All measures explored in both experiments and numerics, including stress tensor derived measures and contact numbers depend in a universal manner on the fraction of non-rattler particles, $f_{NR}$. The force network topology also tends to show this universality, yet the shape of the master curve depends much more on the details of the numerical simulations. In particular we show that adding force noise to the numerical data set can significantly alter the topological features in the data. We conclude that both $f_{NR}$ and topological metrics are useful measures to consider when quantifying the state of a granular system.Comment: 8 pages, 8 figure

Exhaustive enumeration unveils clustering and freezing in random 3-SAT

We study geometrical properties of the complete set of solutions of the random 3-satisfiability problem. We show that even for moderate system sizes the number of clusters corresponds surprisingly well with the theoretic asymptotic prediction. We locate the freezing transition in the space of solutions which has been conjectured to be relevant in explaining the onset of computational hardness in random constraint satisfaction problems.Comment: 4 pages, 3 figure

Multimethod machine learning approach for medical diagnosing

In this paper we present a multimethod approach for induction of a specific class of classifiers, which can assist physicians in medical diagnosing in the case of mitral valve prolapse. Mitral valve prolapse is one of the most controversial prevalent cardiac condition and may affect up to ten percent of the population and in the worst case results in sudden death. MultiVeDec is a general framework enabling researchers to generate various intelligent tools based on machine learning. In this paper we focused on various decision tree methods, which are capable of extracting knowledge in a form closer to human perception, a feature that is very important in medical field. The experiment included classifiers with various classical single method approaches, evolutionary approaches, hybrid approaches and also our newest multimethod approach. The main concern of the latest approach is to rind a way to enable dynamic combination of methodologies to the somehow quasi unified knowledge representation. The proposed multimethod approach was capable to outperform all other tested approaches by producing classifier for diagnosing mitral valve prolapse with the highest overall and average class accuracy

Baroclinic adjustment and dissipative control of storm tracks

The steady-state response of a mid-latitude storm track to large-scale extratropical thermal forcing and eddy friction is investigated in a dry general circulation model with a zonally symmetric forcing. A two-way equilibration is found between the relative responses of the mean baroclinicity and baroclinic eddy intensity, whereby mean baroclinicity responds more strongly to eddy friction whereas eddy intensity responds more strongly to the thermal forcing of baroclinicity. These seemingly counter-intuitive responses are reconciled using the steady state of a predator-prey relationship between baroclinicity and eddy intensity. This relationship provides additional support for the well studied mechanism of baroclinic adjustment in the Earth’s atmosphere, as well as providing a new mechanism whereby eddy dissipation controls the large-scale thermal structure of a baroclinically unstable atmosphere. It is argued that these two mechanisms of baroclinic adjustment and dissipative control should be used in tandem when considering storm track equilibration

Immediate Fitment of Prefabricated Orthoses in Corrective Surgery Camps

In surgical camps, deformity correction and immobilizationby Plaster of Paris (POP) cast is a routine methodfollowed in about four weeks by removal of sutures/plaster and provision of orthosis. A new technique wasdeveloped in which after corrective surgery, instead ofPOP cast pre-fabricated orthosis were fitted in 236 caseswith lower limb deformities following post polio residualparalysi and cerebral palsy.Use of pre-fabricated orthosis, immediately after surgeryin these camps reduced the cost markedly besides beingconvenient to fit the orthosis in one go

Site-specific C-terminal and internal loop labeling of proteins using sortase-mediated reactions

Methods for site-specific modification of proteins should be quantitative and versatile with respect to the nature and size of the biological or chemical targets involved. They should require minimal modification of the target, and the underlying reactions should be completed in a reasonable amount of time under physiological conditions. Sortase-mediated transpeptidation reactions meet these criteria and are compatible with other labeling methods. Here we describe the expression and purification conditions for two sortase A enzymes that have different recognition sequences. We also provide a protocol that allows the functionalization of any given protein at its C terminus, or, for select proteins, at an internal site. The target protein is engineered with a sortase-recognition motif (LPXTG) at the place where modification is desired. Upon recognition, sortase cleaves the protein between the threonine and glycine residues, facilitating the attachment of an exogenously added oligoglycine peptide modified with the functional group of choice (e.g., fluorophore, biotin, protein or lipid). Expression and purification of sortase takes ∼3 d, and sortase-mediated reactions take only a few minutes, but reaction times can be extended to increase yields.National Institutes of Health (U.S.) (Grant RO1 AI08787