1,323 research outputs found

    Diameter Perfect Lee Codes

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    Lee codes have been intensively studied for more than 40 years. Interest in these codes has been triggered by the Golomb-Welch conjecture on the existence of the perfect error-correcting Lee codes. In this paper we deal with the existence and enumeration of diameter perfect Lee codes. As main results we determine all qq for which there exists a linear diameter-4 perfect Lee code of word length nn over Zq,Z_{q}, and prove that for each n3n\geq 3 there are uncountable many diameter-4 perfect Lee codes of word length nn over Z.Z. This is in a strict contrast with perfect error-correcting Lee codes of word length nn over ZZ\,\ as there is a unique such code for n=3,n=3, and its is conjectured that this is always the case when 2n+12n+1 is a prime. We produce diameter perfect Lee codes by an algebraic construction that is based on a group homomorphism. This will allow us to design an efficient algorithm for their decoding. We hope that this construction will turn out to be useful far beyond the scope of this paper

    Soviet Inheritance Cases in American Courts and the Soviet Property Regime

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    Many American states have statutes limiting transmission of monies from estates in this country to citizens of countries behind the Iron Curtain. American courts have come under heavy criticism for construing these statutes unfavorably to foreign heirs, especially where transmission to heirs in the Soviet Union is withheld. This article analyzes the relevant American and Soviet law and concludes that American courts, while they have not always been completely objective, nevertheless may be justified in withholding distribution from Soviet citizens

    An Efficient and Cost Effective FPGA Based Implementation of the Viola-Jones Face Detection Algorithm

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    We present an field programmable gate arrays (FPGA) based implementation of the popular Viola-Jones face detection algorithm, which is an essential building block in many applications such as video surveillance and tracking. Our implementation is a complete system level hardware design described in a hardware description language and validated on the affordable DE2-115 evaluation board. Our primary objective is to study the achievable performance with a low-end FPGA chip based implementation. In addition, we release to the public domain the entire project. We hope that this will enable other researchers to easily replicate and compare their results to ours and that it will encourage and facilitate further research and educational ideas in the areas of image processing, computer vision, and advanced digital design and FPGA prototyping

    Wenn Zellen zu Medikamenten werden : neue Zelltherapien verbessern die Heilungschancen bei Leukämien

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    Die Transplantation von Zellen aus dem Knochenmark oder von Stammzellen aus dem Blut gehört zu den bekanntesten Therapien bei Leukämie. Doch dabei treten Immunreaktionen als Nebenwirkung auf. Deshalb nehmen Forscher seit Kurzem auch die Transplantation bestimmter Immunzellen in den Blick. Im Labor gentechnisch aufgerüstet, werden sie zu äußerst effizienten "Krebs-Medikamenten"

    Single Crystal Growth of FeGa3 and FeGa3−xGex from High‐Temperature Solution Using the Czochralski Method

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    Single crystal growth and characterization of the binary semiconducting compound FeGa3 and its Ge‐substitute FeGa3–xGex are reported. Whereas there have been several investigations on the thermoelectric properties based on small samples grown by the flux method, this study is the first approach using the Czochralski growth technique from well‐oriented single‐crystalline seeds. Problems and solutions of the growth of cm3‐size single crystals are discussed in detail. Ge segregation in FeGa3–xGex is described by a segregation coefficient lower than unity which leads to an axially increasing Ge content along the pulling direction. Consequences with respect to lattice parameter changes and thermoanalytic measurements are reported

    Spin dynamics of FeGa3x_{3-x}Gex_x studied by Electron Spin Resonance

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    The intermetallic semiconductor FeGa3_{3} acquires itinerant ferromagnetism upon electron doping by a partial replacement of Ga with Ge. We studied the electron spin resonance (ESR) of high-quality single crystals of FeGa3x_{3-x}Gex_x for xx from 0 up to 0.162 where ferromagnetic order is observed. For x=0x = 0 we observed a well-defined ESR signal, indicating the presence of pre-formed magnetic moments in the semiconducting phase. Upon Ge doping the occurrence of itinerant magnetism clearly affects the ESR properties below 40\approx 40~K whereas at higher temperatures an ESR signal as seen in FeGa3_{3} prevails independent on the Ge-content. The present results show that the ESR of FeGa3x_{3-x}Gex_x is an appropriate and direct tool to investigate the evolution of 3d-based itinerant magnetism.Comment: 12 pages, 7 figure

    Untersuchungen zum Einfluss des Plattenaufbaus auf ausgewählte Eigenschaften von Massivholzplatten

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    Zusammenfassung: An labortechnisch hergestellten Massivholzplatten aus Fichtenholz wurden die Wärmeleitfähigkeit, die Gleichgewichtsfeuchte, die Längenquellung und der Wasserdampfdiffusionswiderstand bestimmt. Die Wärmeleitfähigkeit liegt im Normalklima im Bereich von 0.09-0.11W/m·K. Hohlräume in der Mittellage (Schlitze, Abstände zwischen den einzelnen Brettlamellen) führen zu einer geringen Reduzierung der Wärmeleitfähigkeit. Auch die Anordnung der Jahrringe wirkt sich aus. Auf den Wasserdampfdiffusionswiderstand haben die Orientierung der Jahrringe in den Lagen und die Hohlräume in den Mittellagen einen Einfluss. Die Gleichgewichtsfeuchte liegt oberhalb von 35% rel. Luftfeuchte etwas unterhalb derjenigen von Fichtenholz. Bei Holzwerkstoffmittellagen ist sie durch die geringere Ausgleichsfeuchte der Holzpartikelwerkstoffe geringer als bei reinen Vollholzmittellage
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