30,621 research outputs found

    The Eternal Unprovability Filter – Part I

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    I prove both the mathematical conjectures P ≠ NP and the Continuum Hypothesis are eternally unprovable using the same fundamental idea. Starting with the Saunders Maclane idea that a proof is eternal or it is not a proof, I use the indeterminacy of human biological capabilities in the eternal future to show that since both conjectures are independent of Axioms and have definitions connected with human biological capabilities, it would be impossible to prove them eternally without the creation and widespread acceptance of new axioms. I also show that the same fundamental concepts cannot be used to demonstrate the eternal unprovability of many other mathematical theorems and open conjectures. Finally I investigate the idea’s implications for the foundations of mathematics including its relation to Godel’s Incompleteness Theorem and Tarsky’s Undefinability Theorem

    Optimal Source Tracking and Beaming of LISA

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    We revisit the directionally optimal data streams of LISA first introduced in Nayak etal. It was shown that by using appropriate choice of Time delay interferometric (TDI) combinations, a monochromatic fixed source in the barycentric frame can be optimally tracked in the LISA frame. In this work, we study the beaming properties of these optimal streams. We show that all the three streams V+, Vx and Vo with maximum, minimum and zero directional SNR respectively are highly beamed. We study in detail the frequency dependence of the beaming.Comment: 8 pages, 9 figures. To appear in the proceedings of Sixth International LISA Symposiu

    A Comparison of Clustering Techniques for Malware Analysis

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    In this research, we apply clustering techniques to the malware detection problem. Our goal is to classify malware as part of a fully automated detection strategy. We compute clusters using the well-known �-means and EM clustering algorithms, with scores obtained from Hidden Markov Models (HMM). The previous work in this area consists of using HMM and �-means clustering technique to achieve the same. The current effort aims to extend it to use EM clustering technique for detection and also compare this technique with the �-means clustering

    Critical exponents of ferromagnetic Ising model on fractal lattices

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    We review the value of the critical exponents ν1\nu^{-1}, β/ν\beta/\nu, and γ/ν\gamma/\nu of ferromagnetic Ising model on fractal lattices of Hausdorff dimension between one and three. They are obtained by Monte Carlo simulation with the help of Wolff algorithm. The results are accurate enough to show that the hyperscaling law df=2β/ν+γ/νd_f=2\beta/\nu+\gamma/\nu is satisfied in non-integer dimension. Nevertheless, the discrepancy between the simulation results and the ϵ\epsilon-expansion studies suggests that the strong universality should be adapted for the fractal lattices.Comment: 5 pages, 1 figure, 1 table; conference article for the sixth international school "Symmetry and Structural Properties of Condensed Matter (SSPCM'2000)" in Polan

    Morphometry of Glenoid Cavity

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    Objectives: Knowledge of the shape and dimensions of the glenoid are important in the design and fitting of glenoid components for total shoulder arthroplasty. An understanding of variations in normal anatomy of the glenoid is essential while evaluating pathological conditions like osseous Bankart lesions and osteochondral defects. Methods: This study was done on 202 dry, unpaired adult human scapulae of unknown sex belonging to the south Indian population. Three glenoid diameters were measured, the superior-inferior diameter, anterior-posterior diameter of the lower half and the anterior-posterior diameter of the upper half of the glenoid. Based on a notch present on the anterior glenoid rim, variations in the shape of the glenoid cavity were classified as inverted comma shaped, pear shaped and oval. Results: The average superior-inferior diameter on right and the left sides were 33.67±2.82mm and 33.92±2.87mm respectively. The average anterior-posterior diameter of the lower half of the right glenoid was 23.35±2.04mm and that of the left was 23.02±2.30mm. The mean diameter of the upper half of the right glenoid was 16.27±2.01mm and that of the left was 15.77±1.96mm. Conclusion: The dimensions of the glenoid observed in the present study were lesser than those recorded in the studies done on other populations. This fact may be taken into consideration while designing glenoid prostheses for the south Indian population. The current study recorded a higher percentage of glenoid cavities having the glenoid notch as compared to earlier studies. While evaluating defects/lesions of the glenoid, this fact could be useful

    Validating delta-filters for resonant bar detectors of improved bandwidth foreseeing the future coincidence with interferometers

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    The classical delta filters used in the current resonant bar experiments for detecting GW bursts are viable when the bandwidth of resonant bars is few Hz. In that case, the incoming GW burst is likely to be viewed as an impulsive signal in a very narrow frequency window. After making improvements in the read-out with new transducers and high sensitivity dc-SQUID, the Explorer-Nautilus have improved the bandwidth (20\sim 20 Hz) at the sensitivity level of 1020/Hz10^{-20}/\sqrt{Hz}. Thus, it is necessary to reassess this assumption of delta-like signals while building filters in the resonant bars as the filtered output crucially depends on the shape of the waveform. This is presented with an example of GW signals -- stellar quasi-normal modes, by estimating the loss in SNR and the error in the timing, when the GW signal is filtered with the delta filter as compared to the optimal filter.Comment: 7 pages, presented in Amaldi6, accepted for publication in Journal of Physics: Conference Serie

    On the Factors that Affect Airline Flight Frequency and Aircraft Size

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    This paper assesses the determinants of aircraft size and frequency of flights on airline routes by considering market demographics, airport characteristics, airline characteristics and route characteristics. The paper shows that frequency and aircraft size increase with population, income, and runway length. An increase in the proportion of managerial workers in the labor force or the proportion of population below the age of 25 results in greater frequency with the use of small planes. Slot constrained airports and an increase in the number of nearby airports lead to lower flight frequency with the use of smaller planes. Hubs and low cost carriers are associated with larger plane sizes and higher frequency, while regional airline ownership leads to higher frequency and the use of smaller planes. An increase in distance between the endpoints leads to lower frequency with the use of larger planes. As airport delay rises, airlines reduce frequency and use smaller planes, though when airport cancellations rise, flight frequency increases with the use of larger planes. This finding suggests airlines utilize frequency and aircraft size to hedge against flight cancellations.Airline; Frequency; Aircraft size; Markets

    Newspaper archives : a knowledge asset

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    This paper deals with Newspaper Content as a source of knowledge and how Times Archives of the Times Group has converted the 166-year span of socio-political content of “The Times of India” and the 43 year economic and business barometer “The Economic Times” into an easily accessible Archive. The value of this Archive as a Knowledge Asset lies in its potential of being recalled, researched, reused and re-expressed by the various ventures of the Group. This paper describes the process of Microfilm Archiving and Digital Archiving of a Newspaper. The advantages and disadvantages of both have been discussed
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