international data encryption algorithm (IDEA) is a secret key or symmetric key block cipher. The purpose of IDEA was to replace dataencryption standard (DES) cipher, which became practically insecure due to its smal...
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international data encryption algorithm (IDEA) is a secret key or symmetric key block cipher. The purpose of IDEA was to replace dataencryption standard (DES) cipher, which became practically insecure due to its small key size of 56 bits and increase in computational power of systems. IDEA cipher mainly to provides data confidentiality in variety of applications such as commercial and financial application e.g. pretty good privacy (PGP) protocol. Till 2015, no successful linear or algebraic weaknesses of IDEA of have been reported. In this paper, author explained IDEA cipher, its application in PGP and did a systematic survey of various attacks attempted on IDEA cipher. The best cryptanalysis result which applied to all keys could break IDEA up to 6 rounds out of 8.5 rounds of the full IDEA cipher(1). But the attack requires 2(64) known plaintexts and 2(126.8) operations for reduced round version. This attack is practically not feasible due to above mentioned mammoth data and time requirements. So IDEA cipher is still completely secure for practical usage. PGP v2.0 uses IDEA cipher in place of BassOmatic which was found to be insecure for providing data confidentiality.
The author gives a detailed account of an approach to multidimensional inverse problems that utilizes ideas and results of the theory of boundary control (J.-***, D. L. Russell, and others). Within the bounds of a sin...
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The author gives a detailed account of an approach to multidimensional inverse problems that utilizes ideas and results of the theory of boundary control (J.-***, D. L. Russell, and others). Within the bounds of a single scheme, formulations of two types are considered: spectral and time-dependent. Multidimensional analogsto the classical Gel'fand-Levitan equations are derived. The potential of the approach and some ideas on numerical realization are ***: 15 titles.
X-ray sources are developing rapidly and their coherent output is growing correspondingly. The increased coherent flux from modern X-ray sources is being matched with an associated development in experimental methods....
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X-ray sources are developing rapidly and their coherent output is growing correspondingly. The increased coherent flux from modern X-ray sources is being matched with an associated development in experimental methods. This article reviews the literature describing the ideas that utilize the increased brilliance from modern X-ray sources. It explores how ideas in coherent X-ray science are leading to developments in other areas, and vice versa. The article describes measurements of coherence properties and uses this discussion as a base from which to describe partially coherent diffraction and X-ray phase-contrast imaging, with applications in materials science, engineering and medicine. Coherent diffraction imaging methods are reviewed along with associated experiments in materials science. Proposals for experiments to be performed with the new X-ray free-electron lasers are briefly discussed. The literature on X-ray photon-correlation spectroscopy is described and the features it has in common with other coherent X-ray methods are identified. Many of the ideas used in the coherent X-ray literature have their origins in the optical and electron communities and these connections are explored. A review of the areas in which ideas from coherent X-ray methods are contributing to methods for the neutron, electron and optical communities is presented.
We present some ideas on self-validating (SV) methods. This note is especially intended to give some background for the articles in this special volume of LAA. It is not intended to be a survey of the big variety of a...
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We present some ideas on self-validating (SV) methods. This note is especially intended to give some background for the articles in this special volume of LAA. It is not intended to be a survey of the big variety of all possible aspects of SV methods but rather a summary of some basic concepts. Especially, some common misconceptions are mentioned and explored. (C) 2001 Elsevier Science Inc. All rights reserved.
作者：
BAMBER, DResearch
Development Test and Evaluation Division of the Naval Command Control and Ocean Surveillance Center NCCOSC RDTE DIV 44209 San Diego CA USA
Symbolic logics that embody different theories of natural-language conditionals (e.g., statements of the form If alpha, then beta) have been developed. One such logic is that of Ernest Adams. Regardless of whether Ada...
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Symbolic logics that embody different theories of natural-language conditionals (e.g., statements of the form If alpha, then beta) have been developed. One such logic is that of Ernest Adams. Regardless of whether Adams' theory of natural-language conditionals is correct, Adams' logic is useful. An Adams conditional alpha > beta expresses the idea that the conditional probability Pr(beta\alpha) is close to one;his logic may be used to reason about such ideas. In particular, Adam's logic may be used to reason about imperfect generalizations such as Nearly every alpha is a beta, provided that such a statement is taken to mean that the conditional probability that a randomly selected object is a beta-given that it is an alpha-is close to one. In Adams' logic, a finite set of premises {phi(1) > psi(1),...,phi(n) > psi(n)} is said to probabilistically entail a finite set of alternative conclusions {eta(1) > mu(1),...,eta(m) > mu(m)} iff(i.e., if and only if), roughly speaking, whenever the conditional probabilities Pr(psi(1)\phi(1)),...,Pr(psi(n)\phi(n)) are all close to one, at least one of the conditional probabilities Pr(mu(1) \ eta(1)),...,Pr(mu(m)\eta(m)) will also be close to one. Adams has developed a test for ascertaining whether a set of premises probabilistically entails a set of alternative conclusions. However, his test is computationally intensive. A new, more efficient test is presented in the first half of this paper. The second half (an appendix) proves that the new test is valid;this appendix can be safely skipped by readers uninterested in proofs.
1. WHAT ARE INTELLIGENT TECHNOLOGIES 2. TRADITIONAL INTELLIGENT TECHNOLOGIES:SEARCH FOR algorithmS, ESPECIALLY FOR algorithmS THAT SOLVE DYNAMIC OPTIMIZATION PROBLEMS *** OF TRADITIONAL INTELLIGENT TECHNOLOGIES 4. BEY...
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1. WHAT ARE INTELLIGENT TECHNOLOGIES 2. TRADITIONAL INTELLIGENT TECHNOLOGIES:SEARCH FOR algorithmS, ESPECIALLY FOR algorithmS THAT SOLVE DYNAMIC OPTIMIZATION PROBLEMS *** OF TRADITIONAL INTELLIGENT TECHNOLOGIES 4. BEYOND TRADITIONAL INTELLIGENT TECHNOLOGIES:MAIN IDEA
According to the Merriam-Webster dictionary, a planimeter is 'an instrument for measuring the area of a plane figure by tracing its boundary line'. Even without knowing how a planimeter works, it is clear from...
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According to the Merriam-Webster dictionary, a planimeter is 'an instrument for measuring the area of a plane figure by tracing its boundary line'. Even without knowing how a planimeter works, it is clear from the definition that the idea behind it is that one can compute the area of a figure just by 'walking' on the boundary. For someone who has taken calculus, this immediately suggests Green's Theorem. The aim of this note is to clarify for others why this principle works. We do this by using points of view from linear algebra to elementary plane geometry in order to obtain an intuitive justification for Green's Theorem. As an application, we show how the reader can easily construct a 'software planimeter'. The idea behind this is certainly not original;the formula for the area of a polygon used in this process (see Theorem 1.2 and Remark 1.5 (3)) is surely folklore for experienced programmers (1). What we would like to emphasize is, on the one hand, the beautiful interplay between various branches of mathematics and elementary computer graphics in this case. On the other hand, since our application is (in our view) particularly fun to work with, we hope that this approach can be successfully used in class as an aid in teaching Green's Theorem, or in a calculus lab, or even to show younger and more inexperienced students that sometimes deep mathematical results can be surprisingly accessible and entertaining.
This broad-brushed look gives an idea of recent developments in Japan's parallel processing technologies. Workstation clusters, vector parallel processing, the dataflow model, and certain core technologies stand o...
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This broad-brushed look gives an idea of recent developments in Japan's parallel processing technologies. Workstation clusters, vector parallel processing, the dataflow model, and certain core technologies stand out. National projects transfer technology to business well, but their focus on specific applications has mixed results.
We demonstrate 100-nm-resolution holographic aerial image monitoring based on lensless Fourier-transform holography at extreme-UV (EUV) wavelengths, using synchrotron-based illumination. This method can be used to mon...
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We demonstrate 100-nm-resolution holographic aerial image monitoring based on lensless Fourier-transform holography at extreme-UV (EUV) wavelengths, using synchrotron-based illumination. This method can be used to monitor the coherent imaging performance of EW lithographic optical systems. The system has been implemented in the EUV phase-shifting point-diffraction interferometer recently developed at Lawrence Berkeley National Laboratory. Here we introduce the idea of the holographic aerial image-recording technique and present imaging performance characterization results for a 10 x Schwarzschild objective, a prototype EW lithographic optic. The results are compared with simulations, and good agreement is obtained. Various object patterns, including phase-shift-enhanced patterns, have been studied. Finally, the application of the holographic aerial image-recording technique to EUV multilayer mask-blank defect characterization is discussed. (C) 2001 Optical Society of America.
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