On Ship Wave Patterns and Their Spectra

1971 ◽  
Vol 15 (01) ◽  
pp. 11-21 ◽  
Author(s):  
E. O. Tuck ◽  
J. I. Collins ◽  
W. H. Wells

The one dimensional and two dimensional spectra of a ship wave pattern have been derived. It is shown that the spectra have distinct signatures containing information on speed, direction, shape, size, and wave resistance of the ship. The speed and direction are readily determined but the relationship of the spectrum to other ship characteristics requires further investigation. Some examples of detailed wave patterns in the wake of a parabolic sided ship have been computed.

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Tao Wu ◽  
Zhenghong Deng ◽  
Qingyue Gu ◽  
Jiwei Xu

We explore the estimation of a two-dimensional (2D) nonsymmetric coherently distributed (CD) source using L-shaped arrays. Compared with a symmetric source, the modeling and estimation of a nonsymmetric source are more practical. A nonsymmetric CD source is established through modeling the deterministic angular signal distribution function as a summation of Gaussian probability density functions. Parameter estimation of the nonsymmetric distributed source is proposed under an expectation maximization (EM) framework. The proposed EM iterative calculation contains three steps in each cycle. Firstly, the nominal azimuth angles and nominal elevation angles of Gaussian components in the nonsymmetric source are obtained from the relationship of rotational invariance matrices. Then, angular spreads can be solved through one-dimensional (1D) searching based on nominal angles. Finally, the powers of Gaussian components are obtained by solving least-squares estimators. Simulations are conducted to verify the effectiveness of the nonsymmetric CD model and estimation technique.


GEODYNAMICS ◽  
2011 ◽  
Vol 2(11)2011 (2(11)) ◽  
pp. 155-157
Author(s):  
B. Ladanivskyy ◽  
◽  

The regional magneto-variational sounding method (aka Z/H method) was used for estimation of the Earth's mantle conductivity model at the Panagurishte (PAG) observatory region. A magneto-variational transfer function is calculated on the base of the relationship of vertical to horizontal geomagnetic field spectra components recorded on the Earth surface and priori assumptions about a field source structure. Inversions of the transfer function allow to obtain the one dimensional conductivity model.


Author(s):  
AKIRA ITO ◽  
KATSUSHI INOUE ◽  
ITSUO TAKANAMI ◽  
YUE WANG

Recently, related to the open problem of whether deterministic and nondeterministic space (especially lower-level) complexity classes are separated, the inkdot Turing machine was introduced. An inkdot machine is a conventional Turing machine capable of dropping an inkdot on a given input tape for a landmark, but not to pick it up nor further erase it. In this paper, we introduce a finite state version of the inkdot machine as a weak recognizer of the properties of digital pictures, rather than a Turing machine supplied with a one-dimensional working tape. We first investigate the sufficient spaces of three-way Turing machines to simulate two-dimensional inkdot finite automaton, as preliminary results. Next, we investigate the basic properties of two-dimensional inkdot automaton, i.e. the hierarchy based on the number of inkdots and the relationship of two-dimensional inkdot automata to other conventional two-dimensional automata. Finally, we investigate the recognizability of connected pictures of two-dimensional inkdot finite machines.


Author(s):  
Geoffrey Hellman ◽  
Stewart Shapiro

This chapter develops a Euclidean, two-dimensional, regions-based theory. As with the semi-Aristotelian account in Chapter 2, the goal here is to recover the now orthodox Dedekind–Cantor continuum on a point-free basis. The chapter derives the Archimedean property for a class of readily postulated orientations of certain special regions, what are called “generalized quadrilaterals” (intended as parallelograms), by which the entire space is covered. Then the chapter generalizes this to arbitrary orientations, and then establishes an isomorphism between the space and the usual point-based one. As in the one-dimensional case, this is done on the basis of axioms which contain no explicit “extremal clause”, and we have no axiom of induction other than ordinary numerical (mathematical) induction.


Elenchos ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 181-194
Author(s):  
Angela Longo

AbstractThe following work features elements to ponder and an in-depth explanation taken on the Anca Vasiliu’s study about the possibilities and ways of thinking of God by a rational entity, such as the human being. This is an ever relevant topic that, however, takes place in relation to Platonic authors and texts, especially in Late Antiquity. The common thread is that the human being is a God’s creature who resembles him and who is image of. Nevertheless, this also applies within the Christian Trinity according to which, not without problems, the Son is the image of the Father. Lastly, also the relationship of the Spirit with the Father and the Son, always within the Trinity, can be considered as a relationship of similarity, but again not without critical issues between the similarity of attributes, on the one hand, and the identity of nature, on the other.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Huang ◽  
Jianguo Lyu ◽  
Guihe Wang ◽  
Hongyan Liu

Vacuum tube dewatering method and light well point method have been widely used in engineering dewatering and foundation treatment. However, there is little research on the calculation method of unsaturated seepage under the effect of vacuum pressure which is generated by the vacuum well. In view of this, the one-dimensional (1D) steady seepage law of unsaturated soil in vacuum field has been analyzed based on Darcy’s law, basic equations, and finite difference method. First, the gravity drainage ability is analyzed. The analysis presents that much unsaturated water can not be drained off only by gravity effect because of surface tension. Second, the unsaturated vacuum seepage equations are built up in conditions of flux boundary and waterhead boundary. Finally, two examples are analyzed based on the relationship of matric suction and permeability coefficient after boundary conditions are determined. The results show that vacuum pressure will significantly enhance the drainage ability of unsaturated water by improving the hydraulic gradient of unsaturated water.


2016 ◽  
Vol 24 (2) ◽  
pp. 245-264
Author(s):  
Andrew P. Wilson

One of the grand scenes of the Passion narratives can be found in John’s Gospel where Pilate, presenting Jesus to the people, proclaims “Behold the man”: “Ecce Homo.” But what exactly does Pilate mean when he asks the reader to “Behold”? This paper takes as its point of departure a roughly drawn picture of Jesus in the “Ecce Homo” tradition and explores the relationship of this picture to its referent in John’s Gospel, via its capacity as kitsch devotional art. Contemporary scholarship on kitsch focuses on what kitsch does, or how it functions, rather than assessing what it is. From this perspective, when “beholding” is understood not for what it reveals but for what it does, John’s scene takes on a very different significance. It becomes a scene that breaks down traditional divisions between big and small stories, subject and object as well as text and context. A kitsch perspective opens up possibilities for locating John’s narrative in unexpected places and experiences. Rather than being a two-dimensional departure from the grandeur of John’s trial scene, kitsch “art” actually provides a lens through which the themes and dynamics of the narrative can be re-viewed with an expansiveness somewhat lacking from more traditional commentary.



2002 ◽  
Vol 12 (03n04) ◽  
pp. 341-358
Author(s):  
KRISHNA M. KAVI ◽  
DINESH P. MEHTA

This paper presents two algorithms for mutual exclusion on optical bus architectures including the folded one-dimensional bus, the one-dimensional array with pipelined buses (1D APPB), and the two-dimensional array with pipelined buses (2D APPB). The first algorithm guarantees mutual exclusion, while the second guarantees both mutual exclusion and fairness. Both algorithms exploit the predictability of propagation delays in optical buses.


2007 ◽  
Vol 21 (02n03) ◽  
pp. 139-154 ◽  
Author(s):  
J. H. ASAD

A first-order differential equation of Green's function, at the origin G(0), for the one-dimensional lattice is derived by simple recurrence relation. Green's function at site (m) is then calculated in terms of G(0). A simple recurrence relation connecting the lattice Green's function at the site (m, n) and the first derivative of the lattice Green's function at the site (m ± 1, n) is presented for the two-dimensional lattice, a differential equation of second order in G(0, 0) is obtained. By making use of the latter recurrence relation, lattice Green's function at an arbitrary site is obtained in closed form. Finally, the phase shift and scattering cross-section are evaluated analytically and numerically for one- and two-impurities.


2009 ◽  
Vol 5 (3) ◽  
pp. 243-261 ◽  
Author(s):  
Melanie L. Williams

This paper was delivered as a plenary lecture, designed to respond to the one-day special conference focus upon links between socio-legal studies and the humanities.1 The paper focuses in particular upon the relationship between law and the humanities. It may be argued that the role of empirically sourced socio-legal research is well accepted, given its tangible utility in terms of producing hard data which can inform and transform policy perspectives. However, scholarly speculation about the relationship between law and the humanities ranges from the indulgent to the hostile. In particular, legal scholars aligning themselves as ‘black letter’ commentators express strong opinions about such links, suggesting that scholarship purporting to establish links between the two fields is essentially spurious, bearing in mind the purposive role of law as a problem-solving mechanism. The paper sets out to challenge such assertions, indicating the natural connections between the two fields and the philosophical necessity of continued interaction, given the fact that certain aspects of human experience and nature cannot be plumbed by doctrine or empiricism or even by combinations of the two. Law must be understood to stand at the nexus of human experience, in a relationship of integrity, where the word is understood to mean both morally principled and culturally integrated. In particular, the development of human qualities, of character and moral sensibility informing normative values – and, ultimately, engagement with the world of law – is a process of subtle cultural as well as psychological significance, and may benefit from interrogation deriving from the wider fields of human discourse.


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