2,202 research outputs found
A Theory of Spatial Regions with Indeterminate Boundaries
No full textThe paper proposes considers the problem of representing and reasoning about spatial regions with undetermined boundaries. First we build a first order theory of such regions and then propose a possible translation this theory into an adaptation of `RCC-theory', a region-based system for representing qualitative spatial relations developed over the last few years (Randell, Cui and Cohn 1992, Cohn, Randell and Cui 1994). The proposed translation is referred to as the `egg-yolk' representation: a region with undetermined boundaries (a `vague region') is represented by a pair of concentric regions with determinate boundaries (`crisp regions'), which provide limits (not necessarily the tightest limits possible) on the range of indeterminacy. 1 Introduction The topic of this paper 1 is how best to deal with vagueness in spatial representation and reasoning, particularly within the framework of `RCC-theory', (Randell, Cui and Cohn 1992, Cohn et al. 1994), which provides a repres..
Extension of RCC*-9 to Complex and Three-Dimensional Features and Its Reasoning System
No full textRCC*-9 is a mereotopological qualitative spatial calculus for simple lines and regions. RCC*-9 can be easily expressed in other existing models for topological relations and thus can be viewed as a candidate for being a “bridge” model among various approaches. In this paper, we present a revised and extended version of RCC*-9, which can handle non-simple geometric features, such as multipolygons, multipolylines, and multipoints, and 3D features, such as polyhedrons and lower-dimensional features embedded in ℝ3. We also run experiments to compute RCC*-9 relations among very large random datasets of spatial features to demonstrate the JEPD properties of the calculus and also to compute the composition tables for spatial reasoning with the calculus
Review of Historical Events (pg.7)
No full textDr. A.G. Rudovic's description of the history of the Red Army invasions of Latvia, Estonia and Lithuania and what occured when the Soviet Union forcebly incorporated masses of innocent people into Soviet GULAGS and Soviet laour camps by means of mass deportatio: as well as the loss of church spiritual leaders and forbidden church services.2.0 Imanta, 2.1.7 Baltic Nations, 2.1.3 Current Latvian Histopry in Europe ( Pre-Post WWII
Moscow doctor A.G. Dreytser – author of "The Notes of an Ambulance physician"
No full textWe have attempted to present the scientific biography of Alexander Grigorievich Dreytser, the author of "The Notes of an Ambulance physician" – a popular documentary work on the life of Moscow and Muscovites during the Great Patriotic War. We have reconstructed the main points of life and activities of A.G. Dreytser and discovered a number of facts in his biography related to his studying at Strasbourg University (1911–1914) and Imperial Moscow University (1915–1917), participation in the First World War and activities in 1918–1941. The analysis of the materials stored in the State Archive of the Russian Federation, the Central State Archive of the City of Moscow, the Russian State Archive of Literature and Art, as well as the personal archive of the Dreytser family, allowed us to clarify many points related to Dreytser's life and activities during the time prior to the creation of The Notes. This article is based upon the results of a comparative analysis of the texts of The Notes and A.G. Dreytser's Ph.D. dissertation "The Material on the Question of Sudden Death: According to the Data of Morgues, Moscow City Emergency Stations and the Department of Clinical Examination of the Central Polyclinic of the People's Commissariat for Health of the USSR". This article considers the hypothesis of the unity of the events that took place in Moscow during the Great Patriotic War and were described in the dissertation and The Notes. More complete historical and biographical data on A.G. Dreytser allowed us to prove the documentary nature of The Notes, expand the scope of known facts about the organisation of medicine during the war and clarify some circumstances of the history of Russian medicine as a whole
A modified Rayleigh conjecture for static problems
No full textAbstractA modified Rayleigh conjecture (MRC) in scattering theory was proposed and justified by the author [A.G. Ramm, Modified Rayleigh conjecture and applications, J. Phys. A 35 (2002) L357–L361]. The MRC allows one to develop efficient numerical algorithms for solving boundary-value problems. It gives an error estimate for solutions. In this paper the MRC is formulated and proved for static problems
The influence of steady blowing and roughness on transitional separated boundary layers
No full textThis paper presents the results of a study between two types of forcing, namely steady blowing and a tripwire, on the control of laminar separated boundary layers. The analysis focuses on the differences in the transition process between these two types of forcing. This effect will be studied using direct numerical simulation. The main differences consists in the coherent structures formed during transition and the overall kinetic energy growth
Andries Vierlingh, Tractaet van dyckagie (eds. J. de Hullu en A.G. Verhoeven)
No full textTranscriptie uit 1920 van het manuscript van Andries Vierlingh uit 1579 over het ontwerp en de aanleg van dijken. Zijn werk is hoofdzakelijk uitgevoerd in West Brabant. De publicatie uit 1920 is later heruitgegeven door de VBKO (Vereniging van Waterbouwers)
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