Aircraft recognition based on the discrepancy of polygon intersection area
Deng, Xiujian; Wang, Yanfang; Feng, Qi
2017-01-01
In this paper, a new algorithm that based on discrepancy of polygon intersection area for aircraft recognition is presented. The recognition algorithm process involves three parts: generating polygon of aircraft, placing overlapping plane polygons and computing the area of total intersecting polygons. For the purpose of getting the polygon of aircraft, the picture that was ready to be recognized has gone through a series of pre-processing and the smallest circumference polygon algorithm was used to get approximate polygon of the target contour. To make the two compared polygons have the approximate area, the similar principle was utilized. The matching procedure was divided into four steps including computing intersecting points, computing polygon intersecting sets, computing the intersecting area and getting the intersecting rate to recognize the aircraft. The data structure of algorithm is based on doubly liked list principle. A mass of simulations illustrate that the proposed algorithm is effective and reasonable.
Coloring intersection graphs of x-monotone curves in the plane
Suk, Andrew
2012-01-01
A class of graphs G is \\chi-bounded if the chromatic number of the graphs in G is bounded by some function of their clique number. We show that the class of intersection graphs of simple x-monotone curves in the plane intersecting a vertical line is \\chi-bounded. As a corollary, the class of intersection graphs of rays in the plane is \\chi-bounded.
Riosa, Blažka
2014-01-01
In mathematics we often encounter polygons, such us triangle, square, hexagon, etc., but we hardly encounter star polygons. Despite the fact that we do not meet them so often in mathematics, in nature they can be traced almost on every step. In this paper the emphasis is on the geometric meaning of regular star polygons. Star polygon is a generalization of the concept of regular polygons. In star polygons also non-adjacent sides intersect. Up to similarity they are determined by Schläfli symb...
A method of dealing polygon's self-intersection contour in SLA
Institute of Scientific and Technical Information of China (English)
GAO Yong-qiang; MO Jian-hua; HUANG Shu-huai
2007-01-01
The contour of the slices of SLA parts is composed of a great deal of small lines. When offsetting the contour to compensate for the radius of laser spot, many self-intersection contours come into being, which decrease the precision of formed parts. A new lemma to judge the local self-intersection contour and the global self-intersection contour separately is put forward, according to which self-intersection contour can be removed reliably. Meanwhile, a new beam offsetting algorithm for SLA parts is described, which brings about good results in the practical manufacturing process.
Monotone Increasing Properties and Their Phase Transitions in Uniform Random Intersection Graphs
Zhao, Jun; Gligor, Virgil
2015-01-01
Uniform random intersection graphs have received much interest and been used in diverse applications. A uniform random intersection graph with $n$ nodes is constructed as follows: each node selects a set of $K_n$ different items uniformly at random from the same pool of $P_n$ distinct items, and two nodes establish an undirected edge in between if and only if they share at least one item. For such graph denoted by $G(n, K_n, P_n)$, we present the following results in this paper. First, we provide an exact analysis on the probabilities of $G(n, K_n, P_n)$ having a perfect matching and having a Hamilton cycle respectively, under $P_n = \\omega\\big(n (\\ln n)^5\\big)$ (all asymptotic notation are understood with $n \\to \\infty$). The analysis reveals that just like ($k$-)connectivity shown in prior work, for both properties of perfect matching containment and Hamilton cycle containment, $G(n, K_n, P_n)$ also exhibits phase transitions: for each property above, as $K_n$ increases, the limit of the probability that $G...
Boolean Operations on Conic Polygons
Institute of Scientific and Technical Information of China (English)
Yong-Xi Gong; Yu Liu; Lun Wu; Yu-Bo Xie
2009-01-01
An algorithm for Boolean operations on conic polygons is proposed. Conic polygons are polygons consisting of conic segments or bounded conics with directions. Preliminaries of Boolean operations on general polygons are presented. In our algorithm, the intersection points and the topological relationships between two conic polygons are computed. Boundaries are obtained by tracking path and selecting uncrossed boundaries following rule tables to build resulting conic polygons.We define a set of rules for the intersection, union, and subtraction operations on conic polygons. The algorithm considers degeneration cases such as homology, complement, interior, and exterior. The algorithm is also evaluated and implemented.
GPC: General Polygon Clipper library
Murta, Alan
2015-12-01
The University of Manchester GPC library is a flexible and highly robust polygon set operations library for use with C, C#, Delphi, Java, Perl, Python, Haskell, Lua, VB.Net and other applications. It supports difference, intersection, exclusive-or and union clip operations, and polygons may be comprised of multiple disjoint contours. Contour vertices may be given in any order - clockwise or anticlockwise, and contours may be convex, concave or self-intersecting, and may be nested (i.e. polygons may have holes). Output may take the form of either polygon contours or tristrips, and hole and external contours are differentiated in the result.
A Min-max Relation for Monotone Path Systems in Simple Regions
DEFF Research Database (Denmark)
Cameron, Kathleen
1996-01-01
A monotone path system (MPS) is a finite set of pairwise disjointpaths (polygonal arcs) in the plane such that every horizontal line intersectseach of the paths in at most one point. We consider a simple polygon in thexy-plane which bounds the simple polygonal (closed) region D. Let T and B betwo...
Van Maldeghem, Hendrik
1998-01-01
Generalized Polygons is the first book to cover, in a coherent manner, the theory of polygons from scratch. In particular, it fills elementary gaps in the literature and gives an up-to-date account of current research in this area, including most proofs, which are often unified and streamlined in comparison to the versions generally known. Generalized Polygons will be welcomed both by the student seeking an introduction to the subject as well as the researcher who will value the work as a reference. In particular, it will be of great value for specialists working in the field of generalized polygons (which are, incidentally, the rank 2 Tits-buildings) or in fields directly related to Tits-buildings, incidence geometry and finite geometry. The approach taken in the book is of geometric nature, but algebraic results are included and proven (in a geometric way!). A noteworthy feature is that the book unifies and generalizes notions, definitions and results that exist for quadrangles, hexagons, octagons - in the ...
Maldeghem, Hendrik
1998-01-01
This book is intended to be an introduction to the fascinating theory ofgeneralized polygons for both the graduate student and the specialized researcher in the field. It gathers together a lot of basic properties (some of which are usually referred to in research papers as belonging to folklore) and very recent and sometimes deep results. I have chosen a fairly strict geometrical approach, which requires some knowledge of basic projective geometry. Yet, it enables one to prove some typically group-theoretical results such as the determination of the automorphism groups of certain Moufang polygons. As such, some basic group-theoretical knowledge is required of the reader. The notion of a generalized polygon is a relatively recent one. But it is one of the most important concepts in incidence geometry. Generalized polygons are the building bricks of Tits buildings. They are the prototypes and precursors of more general geometries such as partial geometries, partial quadrangles, semi-partial ge ometries, near...
MONOTONIZATION IN GLOBAL OPTIMIZATION
Institute of Scientific and Technical Information of China (English)
WU ZHIYOU; BAI FUSHENG; ZHANG LIANSHENG
2005-01-01
A general monotonization method is proposed for converting a constrained programming problem with non-monotone objective function and monotone constraint functions into a monotone programming problem. An equivalent monotone programming problem with only inequality constraints is obtained via this monotonization method. Then the existingconvexification and concavefication methods can be used to convert the monotone programming problem into an equivalent better-structured optimization problem.
Lu, Yanyan
2012-08-01
Decomposing a shape into visually meaningful parts comes naturally to humans, but recreating this fundamental operation in computers has been shown to be difficult. Similar challenges have puzzled researchers in shape reconstruction for decades. In this paper, we recognize the strong connection between shape reconstruction and shape decomposition at a fundamental level and propose a method called α-decomposition. The α-decomposition generates a space of decompositions parameterized by α, the diameter of a circle convolved with the input polygon. As we vary the value of α, some structural features appear and disappear quickly while others persist. Therefore, by analyzing the persistence of the features, we can determine better decompositions that are more robust to both geometrical and topological noises. © 2012 Elsevier Ltd. All rights reserved.
Inaccessibility-Inside Theorem for Point in Polygon
Sinha, Shriprakash
2010-01-01
The paper explores the ideology behind the concept of inside a simple or self intersecting polygon by presenting new definitions on Inaccessibility and Inside for a point S related to a polygon P. It further goes on to give a theoretical proof to establish a relation as to when a point is inaccessible and inside a polygon. The proposed analytical solution depicts a novel way of tackling the well known point in polygon problem by employing the properties of epigraphs and hypographs, explicitly. Contrary to the ambiguous solutions given by the cross over for the simple and self intersecting polygons and the solution of a point being multi-ply inside a self intersecting polygon given by the winding number rule, the current solution gives unambiguous and singular result for both kinds of polygons. The solution also deals with the rare and subtle issues of ray crossing a odd or even number of vertices, an edge as well as analytically questions the idea of a point being multi-ply inside a polygon. Finally, the curr...
Monotone Boolean approximation
Energy Technology Data Exchange (ETDEWEB)
Hulme, B.L.
1982-12-01
This report presents a theory of approximation of arbitrary Boolean functions by simpler, monotone functions. Monotone increasing functions can be expressed without the use of complements. Nonconstant monotone increasing functions are important in their own right since they model a special class of systems known as coherent systems. It is shown here that when Boolean expressions for noncoherent systems become too large to treat exactly, then monotone approximations are easily defined. The algorithms proposed here not only provide simpler formulas but also produce best possible upper and lower monotone bounds for any Boolean function. This theory has practical application for the analysis of noncoherent fault trees and event tree sequences.
Don, Henk
2011-01-01
We study the geometry of billiard orbits on rectangular billiards. A truncated billiard orbit induces a partition of the rectangle into polygons. We prove that thirteen is a sharp upper bound for the number of different areas of these polygons.
Energy Technology Data Exchange (ETDEWEB)
Korshunov, A D [S.L. Sobolev Institute for Mathematics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)
2003-10-31
Monotone Boolean functions are an important object in discrete mathematics and mathematical cybernetics. Topics related to these functions have been actively studied for several decades. Many results have been obtained, and many papers published. However, until now there has been no sufficiently complete monograph or survey of results of investigations concerning monotone Boolean functions. The object of this survey is to present the main results on monotone Boolean functions obtained during the last 50 years.
Ergodicity of polygonal slap maps
Del Magno, Gianluigi; Lopes Dias, João; Duarte, Pedro; Gaivão, José Pedro
2014-08-01
Polygonal slap maps are piecewise affine expanding maps of the interval obtained by projecting the sides of a polygon along their normals onto the perimeter of the polygon. These maps arise in the study of polygonal billiards with non-specular reflection laws. We study the absolutely continuous invariant probabilities (acips) of the slap maps for several polygons, including regular polygons and triangles. We also present a general method for constructing polygons with slap maps with more than one ergodic acip.
Fixing Geometric Errors on Polygonal Models: A Survey
Institute of Scientific and Technical Information of China (English)
Tao Ju
2009-01-01
Polygonal models are popular representations of 3D objects. The use of polygonal models in computational applications often requires a model to properly bound a 3D solid. That is, the polygonal model needs to be closed, manifold, and free of self-intersections. This paper surveys a sizeable literature for repairing models that do not satisfy this criteria, focusing on categorizing them by their methodology and capability. We hope to offer pointers to further readings for researchers and practitioners, and suggestions of promising directions for future research endeavors.
Line clipping against polygonal window algorithm based on the multiple virtual boxes rejecting
Institute of Scientific and Technical Information of China (English)
WANG Jin; LU Guo-dong; PENG Qun-sheng; WU Xuan-hui
2005-01-01
This paper presents a new algorithm for line clipping against a polygonal window by exploiting the local relationship between each line segment and the polygon. Firstly, a minimal enclosing box (MEB) of the polygon is adopted to reject the invisible line segments located outside the MEB. Secondly, a 45° rotated box is used to encode the endpoint of the line segment, and then reject a portion of the invisible segments crossing polygon corners. Finally, instead of encoding the endpoints of all line segments with respect to the polygonal window, each vertex of the polygon is encoded, taking the line segment to be clipped as reference. For efficient encoding of the polygon vertices, a new concept, termed with slope adaptive virtual box, is introduced regarding each line segment. Such a box can not only conveniently reject all totally invisible lines lying outside the MEB conveniently, but also precisely identify the edges of the polygon with which the line segment potentially intersects. With the summation of the vertex codes, it can be verified whether the line segment is separated from or potentially intersects the polygon window. Based on the product of the codes of adjacent vertices, singular cases of intersection can be solved accurately. Experimental results demonstrate the efficiency and stability of the new algorithm.
Directory of Open Access Journals (Sweden)
Pedro Pina
2009-06-01
Full Text Available The presence of water ice on Mars is well established. Some featureson the planet point to the occurrence of processes similar to those that take place in periglacial areas of Earth. One of the clues for this is the existence of small-scale polygonal terrains. In this paper, we present a methodology that aims at the automated identification of polygonal patterns on high-spatial resolution images of the surface of Mars. In the context of the research project TERPOLI, this step will be complemented with a full characterization, in both geometric and topological terms, of thenetworks detected. In this manner, we hope to collect data that will lead to a better understanding of the conditions of formation of the polygons, and of their temporal evolution; namely, we intend to identify different groups of polygons and to compare them with terrestrial examples.
Evoluton of polygonal fracture patterns in lava flows.
Aydin, A; Degraff, J M
1988-01-29
Cooling-induced fractures, also known as columnar joints, divide basaltic lava flows into prismatic columns with polygonal cross sections. The regularity and symmetry of the fracture patterns have long fascinated naturalists. In view of the recent selection of two candidate nuclear waste sites in areas where polygonally fractured volcanic rocks are located, a better understanding of the fracture patterns is required. Field data indicate that the tetragonal networks at flow surfaces evolve systematically to hexagonal networks as the joints grow inward during solidification of lava. This evolution occurs by the gradual change of most orthogonal intersections to nonorthogonal intersections of about 120 degrees. The surface features and intersection geometries of columnar joints show that joint segments at any given level form sequentially yet harmoniously.
Polygonal Ridge Networks on Mars
Kerber, Laura; Dickson, James; Grosfils, Eric; Head, James W.
2016-10-01
Polygonal ridge networks, also known as boxwork or reticulate ridges, are found in numerous locations and geological contexts across Mars. While networks formed from mineralized fractures hint at hot, possibly life-sustaining circulating ground waters, networks formed by impact-driven clasting diking, magmatic dikes, gas escape, or lava flows do not have the same astrobiological implications. Distinguishing the morphologies and geological context of the ridge networks sheds light on their potential as astrobiological and mineral resource sites of interest. The most widespread type of ridge morphology is characteristic of the Nili Fossae and Nilosyrtis region and consists of thin, criss-crossing ridges with a variety of heights, widths, and intersection angles. They are found in ancient Noachian terrains at a variety of altitudes and geographic locations and may be a mixture of clastic dikes, brecciated dikes, and mineral veins. They occur in the same general areas as valley networks and ancient lake basins, but they are not more numerous where these features are concentrated, and can appear in places where they morphologies are absent. Similarly, some of the ridge networks are associated with hydrated mineral detections, but some occur in locations without detections. Smaller, light-toned ridges of variable widths have been found in Gale Crater and other rover sites and are interpreted to be smaller version of the Nili-like ridges, in this case formed by the mineralization of fractures. This type of ridge is likely to be found in many other places on Mars as more high-resolution data becomes available. Hellas Basin is host to a third type of ridge morphology consisting of large, thick, light-toned ridges forming regular polygons at several superimposed scales. While still enigmatic, these are most likely to be the result of sediment-filled fractures. The Eastern Medusae Fossae Formation contains large swaths of a fourth, previously undocumented, ridge network type
Guionnet, A
2012-01-01
By solving a free analog of the Monge-Amp\\`ere equation, we prove a non-commutative analog of Brenier's monotone transport theorem: if an $n$-tuple of self-adjoint non-commutative random variables $Z_{1},...,Z_{n}$ satisfies a regularity condition (its conjugate variables $\\xi_{1},...,\\xi_{n}$ should be analytic in $Z_{1},...,Z_{n}$ and $\\xi_{j}$ should be close to $Z_{j}$ in a certain analytic norm), then there exist invertible non-commutative functions $F_{j}$ of an $n$-tuple of semicircular variables $S_{1},...,S_{n}$, so that $Z_{j}=F_{j}(S_{1},...,S_{n})$. Moreover, $F_{j}$ can be chosen to be monotone, in the sense that $F_{j}=\\mathscr{D}_{j}g$ and $g$ is a non-commutative function with a positive definite Hessian. In particular, we can deduce that $C^{*}(Z_{1},...,Z_{n})\\cong C^{*}(S_{1},...,S_{n})$ and $W^{*}(Z_{1},...,Z_{n})\\cong L(\\mathbb{F}(n))$. Thus our condition is a useful way to recognize when an $n$-tuple of operators generate a free group factor. We obtain as a consequence that the q-deforme...
FEMA DFIRM Panel Scheme Polygons
Minnesota Department of Natural Resources — This layer contains information about the Flood Insurance Rate Map (FIRM) panel areas. The spatial entities representing FIRM panels are polygons. The polygon for...
A new measure for the rectilinearity of polygons
Zunic, Jovisa; Rosin, Paul L.
2002-11-01
A polygon Pis said to be rectilinear if all interior angles of P belong to the set {π/2, 3π/2}. In this paper we establish the mapping R(P)=(π/(π-2x√2))⊗(maxα∈[0,2π] ((P1(P,α)/√2⊗P2(P))-((2√2)/π)) where P is an arbitrary polygon, P2(P) denotes the Euclidean perimeter of P, while P1(P,α) is the perimeter in the sense of l1 metrics of the polygon obtained by the rotation of P by angle α with the origin as the center of the applied rotation. It turns out that R(P) can be used as an estimate for the rectilinearity of P. Precisely, R(P) has the following desirable properties: - any polygon P has the estimated rectilinearity R(P) which is a number from [0,1]; - R(P)=1 if and only if P is a rectilinear polygon; - infp∈II R(P) = 0, where II denotes the set of all polygons - a polygon's rectilinearity measure is invariant under similarity transformations. The proposed rectilinearity measure can be an alternative for the recently described measure R1(P)1. Those rectilinearity measures are essentially different since there is no monotonic function f, such that f(R1(P))= R(P), that holds for all P ∈ II. A simple procedure for computing R(P) for a given polygon P is described as well.
2005-01-01
14 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a typical view of polygon-cracked and pitted surfaces unique to western Utopia Planitia. No other place on Mars has this appearance. Some Mars scientists have speculated that ground ice may be responsible for these landforms. Location near: 42.3oN, 275.6oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Summer
2003-01-01
MGS MOC Release No. MOC2-339, 23 April 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a pattern of polygonal cracks and aligned, elliptical pits in western Utopia Planitia. The picture covers an area about 3 km (about 1.9 mi) wide near 44.9oN, 274.7oW. Sunlight illuminates the scene from the left.
DEFF Research Database (Denmark)
Marfelt, Mikkel Mouritz
2016-01-01
oriented but still emphasizes stable concepts. Moreover, it does not give primacy to oppression. Finally, it adopts a critical stance on the nature of the macro, meso, and micro levels as dominant analytical perspectives. As a result, this paper focusses on the importance of intersectionality...
Institute of Scientific and Technical Information of China (English)
Barbara Harbin Cobb
2009-01-01
<正>I’m a few years older than the People’s Re- public of China, but hardly an infant compared to China’s vast history and culture. China and I have intersected at many points, and I want to tell you about a few of them.
Monotone partitions and almost partitions
Bonanzinga, M.; Cammaroto, F.; van Mill, J.; Pansera, B.A.
2014-01-01
In this paper we are interested in monotone versions of partitionability of topological spaces and weak versions thereof. We identify several classes of spaces with these properties by constructing trees of open sets with various properties.
Ferrara, S; Morales, J F; Samtleben, H
2009-01-01
We apply the entropy formalism to the study of the near-horizon geometry of extremal black p-brane intersections in D>5 dimensional supergravities. The scalar flow towards the horizon is described in terms an effective potential given by the superposition of the kinetic energies of all the forms under which the brane is charged. At the horizon active scalars get fixed to the minima of the effective potential and the entropy function is given in terms of U-duality invariants built entirely out of the black p-brane charges. The resulting entropy function reproduces the central charges of the dual boundary CFT and gives rise to a Bekenstein-Hawking like area law. The results are illustrated in the case of black holes and black string intersections in D=6, 7, 8 supergravities where the effective potentials, attractor equations, moduli spaces and entropy/central charges are worked out in full detail.
Evacuation of rectilinear polygons
Fekete, Sandor P; Kroeller, Alexander
2010-01-01
We investigate the problem of creating fast evacuation plans for buildings that are modeled as grid polygons, possibly containing exponentially many cells. We study this problem in two contexts: the ``confluent'' context in which the routes to exits remain fixed over time, and the ``non-confluent'' context in which routes may change. Confluent evacuation plans are simpler to carry out, as they allocate contiguous regions to exits; non-confluent allocation can possibly create faster evacuation plans. We give results on the hardness of creating the evacuation plans and strongly polynomial algorithms for finding confluent evacuation plans when the building has two exits. We also give a pseudo-polynomial time algorithm for non-confluent evacuation plans. Finally, we show that the worst-case bound between confluent and non-confluent plans is 2-2/(k+1).
Why Monotonous Repetition is Unsatisfying
Salingaros, Nikos A
2011-01-01
Human beings prefer ordered complexity and not randomness in their environment, a result of our perceptual system evolving to interpret natural forms. We also recognize monotonously repeating forms as unnatural. Although widespread in today's built environment, such forms generate reactions ranging from boredom to unease. Christopher Alexander has introduced rules for generating forms adapted to natural geometries, which show structured variation with multiple symmetries in a hierarchy of scales. It turns out to be impossible to generate monotonously repeating forms by following those rules. As it is highly probable that traditional artifacts, buildings, and cities were created instinctively using a version of the same rules, this is the reason we never find monotonously repeating forms in traditional cultures.
Monotonicity of social welfare optima
DEFF Research Database (Denmark)
Hougaard, Jens Leth; Østerdal, Lars Peter Raahave
2010-01-01
This paper considers the problem of maximizing social welfare subject to participation constraints. It is shown that for an income allocation method that maximizes a social welfare function there is a monotonic relationship between the incomes allocated to individual agents in a given coalition...... (with at least three members) and its participation constraint if and only if the aggregate income to that coalition is always maximized. An impossibility result demonstrates that there is no welfare maximizing allocation method in which agents' individual incomes monotonically increase in society......'s income. Thus, for any such allocation method, there are situations where some agents have incentives to prevent society in becoming richer....
Virginia ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and brackishwater fish species in Virginia. Vector polygons in this data...
Alabama ESI: HABITATS (Habitat Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for submerged aquatic vegetation (SAV) and rare plants in Alabama. Vector polygons in this data set...
Virginia ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and rare invertebrate species in Virginia. Vector polygons in this data set...
Virginia ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Virginia ESI: Wetlands (Wetland Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the coastal wetlands for Virginia, classified according to the Environmental Sensitivity Index (ESI)...
Maryland ESI: HABITATS (Habitat Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for submerged aquatic vegetation (SAV) and rare plants in Maryland. Vector polygons in this data set...
Soils - Volusia County Soils (Polygons)
NSGIC GIS Inventory (aka Ramona) — Soils: 1:24000 SSURGO Map. Polygon boundaries of Soils in Volusia County, downloaded from SJRWMD and created by NRCS and SJRWMD. This data set is a digital version...
Hawaii ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for reef, marine, estuarine, and native stream fish species in coastal Hawaii. Vector polygons in this data...
Virginia ESI: REPTILES (Reptile Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles and estuarine turtles in Virginia. Vector polygons in this data set represent turtle...
Alabama ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, and freshwater fish species in Alabama. Vector polygons in this data set represent...
Carpinteria Salt Marsh Habitat Polygons
U.S. Geological Survey, Department of the Interior — We identified five common habitat types in Carpinteria Salt Marsh: channels, pans (flats), marsh, salt flat and upland. We then drew polygons around each habitat...
Louisiana ESI: BIRDS (Bird Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for waterfowl species and shorebirds in coastal Louisiana. Vector polygons in this data set represent...
Louisiana ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Hawaii ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of the U.S. Geological Survey 1:24,000 topographic maps and other map and digital data boundaries...
Alabama ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species in Alabama. Vector polygons in this data set represent...
Virginia ESI: HABITATS (Habitat Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for submerged aquatic vegetation (SAV) and rare terrestrial plants/communities in Virginia. Vector polygons...
Control Point Generated PLS - polygons
Minnesota Department of Natural Resources — The Control Point Generated PLS layer contains line and polygon features to the 1/4 of 1/4 PLS section (approximately 40 acres) and government lot level. The layer...
Maryland ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Louisiana ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for freshwater (inland) fish species in coastal Louisiana. Vector polygons represent water-bodies and other...
Borel, Armand
1984-01-01
This book is a publication in Swiss Seminars, a subseries of Progress in Mathematics. It is an expanded version of the notes from a seminar on intersection cohomology theory, which met at the University of Bern, Switzerland, in the spring of 1983. This volume supplies an introduction to the piecewise linear and sheaf-theoretic versions of that theory as developed by M. Goresky and R. MacPherson in Topology 19 (1980), and in Inventiones Mathematicae 72 (1983). While some familiarity with algebraic topology and sheaf theory is assumed, the notes include a self-contained account of further material on constructibility, derived categories, Verdier duality, biduality, and on stratified spaces, which is used in the second paper but not found in standard texts. "The volume should be useful to someone interested in acquiring some basic knowledge about the field..." —Mathematical Reviews.
A Characterization of Generalized Monotone Normed Cones
Institute of Scientific and Technical Information of China (English)
S.ROMAGUERA; E.A.S(A)NCHEZ-P(E)REZ; O.VALERO
2007-01-01
Let C be a cone and consider a quasi-norm p defined on it. We study the structure of the couple (C, p) as a topological space in the case where the function p is also monotone. We characterize when the topology of a quasi-normed cone can be defined by means of a monotone norm. We also define and study the dual cone of a monotone normed cone and the monotone quotient of a general cone.We provide a decomposition theorem which allows us to write a cone as a direct sum of a monotone subcone that is isomorphic to the monotone quotient and other particular subcone.
Orthogonal systems of Zernike type in polygons and polygonal facets
Ferreira, Chelo; Navarro, Rafael; Sinusia, Ester Perez
2015-01-01
Zernike polynomials are commonly used to represent the wavefront phase on circular optical apertures, since they form a complete and orthonormal basis on the unit disk. In [Diaz et all, 2014] we introduced a new Zernike basis for elliptic and annular optical apertures based on an appropriate diffeomorphism between the unit disk and the ellipse and the annulus. Here, we present a generalization of this Zernike basis for a variety of important optical apertures, paying special attention to polygons and the polygonal facets present in segmented mirror telescopes. On the contrary to ad hoc solutions, most of them based on the Gram-Smith orthonormalization method, here we consider a piece-wise diffeomorphism that transforms the unit disk into the polygon under consideration. We use this mapping to define a Zernike-like orthonormal system over the polygon. We also consider ensembles of polygonal facets that are essential in the design of segmented mirror telescopes. This generalization, based on in-plane warping of...
A novel complex-system-view-based method for system effectiveness analysis: Monotonic indexes space
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Based on the characteristics of the complex system, this paper presents a novel method, the monotonic indexes space method, for the effectiveness analysis of the complex system. First, it presents some basic concepts and assumption such as the monotonic indexes space, monotonic indexes requirement locus, etc. Second, based on the assumption that indexes are monotonic for the requirements, an algorithm is proposed and applied to numerical approximation of monotonic indexes requirement locus with hyperboxes. Third, this paper proposes two algorithms for acquiring intersection of several monotonic indexes requirement locus. Fourth, this paper proposes the monotonic-index- space based system analysis model such as the system evaluation model, the sensitivity analysis model for indexes. Based on the practical requirement, the concept of fuzzy monotonic indexes requirement locus and the corresponding analysis model are introduced. Finally, this paper applies the above-mentioned models to analyze the effectiveness of a notional anti-stealth-air-defense information system. And the outputs show that the method is promising.
Testing Monotonicity of Pricing Kernels
Timofeev, Roman
2007-01-01
In this master thesis a mechanism to test mononicity of empirical pricing kernels (EPK) is presented. By testing monotonicity of pricing kernel we can determine whether utility function is concave or not. Strictly decreasing pricing kernel corresponds to concave utility function while non-decreasing EPK means that utility function contains some non-concave regions. Risk averse behavior is usually described by concave utility function and considered to be a cornerstone of classical behavioral ...
Monotonicity of chi-square test statistics
Ryu, Keunkwan
2003-01-01
This paper establishes monotonicity of the chi-square test statistic. As the more efficient parameter estimator is plugged into the test statistic, the degrees of freedom of the resulting chi-square test statistic monotonically increase.
Some Generalizations of Monotonicity Condition and Applications
Institute of Scientific and Technical Information of China (English)
虞旦盛; 周颂平
2006-01-01
@@ O Introduction It is well known that there are a great number of interesting results in Fourier analysis established by assuming monotonicity of coefficients, and many of them have been generalized by loosing the condition to quasi-monotonicity, O-regularly varying quasi-monotonicity, etc..
Interactive display of polygonal data
Energy Technology Data Exchange (ETDEWEB)
Wood, P.M.
1977-10-01
Interactive computer graphics is an excellent approach to many types of applications. It is an exciting method of doing geographic analysis when desiring to rapidly examine existing geographically related data or to display specially prepared data and base maps for publication. One such program is the interactive thematic mapping system called CARTE, which combines polygonal base maps with statistical data to produce shaded maps using a variety of shading symbolisms on a variety of output devices. A polygonal base map is one where geographic entities are described by points, lines, or polygons. It is combined with geocoded data to produce special subject or thematic maps. Shading symbolisms include texture shading for areas, varying widths for lines, and scaled symbols for points. Output devices include refresh and storage CRTs and auxiliary Calcomp or COM hardcopy. The system is designed to aid in the quick display of spatial data and in detailed map design.
DEFF Research Database (Denmark)
Nielson, Hanne Riis; Nielson, Flemming
2009-01-01
The calculus of communicating systems, CCS, was introduced by Robin Milner as a calculus for modelling concurrent systems. Subsequently several techniques have been developed for analysing such models in order to get further insight into their dynamic behaviour. In this paper we present a static...... analysis for approximating the control structure embedded within the models. We formulate the analysis as an instance of a monotone framework and thus draw on techniques that often are associated with the efficient implementation of classical imperative programming languages. We show how to construct...
An Optimal Online Algorithm for Halfplane Intersection
Institute of Scientific and Technical Information of China (English)
WU Jigang; JI Yongchang; CHEN Guoliang
2000-01-01
The intersection of N halfplanes is a basic problem in computational geometry and computer graphics. The optimal offiine algorithm for this problem runs in time O(N log N). In this paper, an optimal online algorithm which runs also in time O(N log N) for this problem is presented. The main idea of the algorithm is to give a new definition for the left side of a given line, to assign the order for the points of a convex polygon, and then to use binary search method in an ordered vertex set. The data structure used in the algorithm is no more complex than array.
Oehler, Dorothy Z.; Mangold, Nicolas; Hallet, Bernard; Fairén, Alberto G.; Deit, Laetitia Le; Williams, Amy J.; Sletten, Ronald S.; Martínez-Frías, Jesús
2016-10-01
Decameter-scale polygons are extensively developed in the Bedded Fractured (BF) Unit of the lower Peace Vallis fan. The polygons occur in a likely extension of the Gillespie Lake Member, north of Yellowknife Bay, the section first drilled by the Mars Science Laboratory (MSL) mission. We examine hypotheses for the origin of these polygons to provide insight into the history of Gale crater. The polygons are ∼4-30 m across, square to rectangular, and defined by ∼0.5-4 m wide, generally straight troughs with orthogonal intersections. Polygon networks are typically oriented-orthogonal systems, with occasional nearly circular patterns, hundreds of meters across. Potential origins include cooling of lava, and for sedimentary units, syneresis, unloading, weathering, desiccation, impact processes, and cold-climate thermal contraction. Cold-climate thermal contraction is the hypothesis most consistent with the sedimentary nature of the BF Unit and the polygon morphology, geometry, networks, and apparent restriction to the coarse-grained Gillespie Lake Member. A periglacial setting further provides the best analogs for the circular networks and is consistent with geologic context and MSL data. Most of the decametric polygons appear to be ancient. They are confined to the Hesperian BF Unit, and only a few of their bounding fractures extend into younger or recently exposed units. In this regard, they differ from the majority of proposed thermal-contraction polygons on Mars, as those are generally thought to be young features, and, accordingly, the history of formation, preservation and reactivation of the decametric polygons is likely to be more complex than that of any proposed young polygons on Mars. The decametric polygons in the BF Unit may represent landforms developed in a cold but still comparatively wet interlude between a clement early Mars and the much drier and colder planet of today.
The average crossing number of equilateral random polygons
Diao, Y.; Dobay, A.; Kusner, R. B.; Millett, K.; Stasiak, A.
2003-11-01
In this paper, we study the average crossing number of equilateral random walks and polygons. We show that the mean average crossing number ACN of all equilateral random walks of length n is of the form \\frac{3}{16} n \\ln n +O(n) . A similar result holds for equilateral random polygons. These results are confirmed by our numerical studies. Furthermore, our numerical studies indicate that when random polygons of length n are divided into individual knot types, the \\langle ACN({\\cal K})\\rangle for each knot type \\cal K can be described by a function of the form \\langle ACN({\\cal K})\\rangle=a (n-n_0) \\ln (n-n_0)+b (n-n_0)+c where a, b and c are constants depending on \\cal K and n0 is the minimal number of segments required to form \\cal K . The \\langle ACN({\\cal K})\\rangle profiles diverge from each other, with more complex knots showing higher \\langle ACN({\\cal K})\\rangle than less complex knots. Moreover, the \\langle ACN({\\cal K})\\rangle profiles intersect with the langACNrang profile of all closed walks. These points of intersection define the equilibrium length of \\cal K , i.e., the chain length n_e({\\cal K}) at which a statistical ensemble of configurations with given knot type \\cal K —upon cutting, equilibration and reclosure to a new knot type \\cal K^\\prime —does not show a tendency to increase or decrease \\langle ACN({\\cal K^\\prime)}\\rangle . This concept of equilibrium length seems to be universal, and applies also to other length-dependent observables for random knots, such as the mean radius of gyration langRgrang.
On the sample monotonization problem
Takhanov, R. S.
2010-07-01
The problem of finding a maximal subsample in a training sample consisting of the pairs “object-answer” that does not violate monotonicity constraints is considered. It is proved that this problem is NP-hard and that it is equivalent to the problem of finding a maximum independent set in special directed graphs. Practically important cases in which a partial order specified on the set of answers is a complete order or has dimension two are considered in detail. It is shown that the second case is reduced to the maximization of a quadratic convex function on a convex set. For this case, an approximate polynomial algorithm based on linear programming theory is proposed.
INTERSECTIONAL DISCRIMINATION AGAINST CHILDREN
DEFF Research Database (Denmark)
Ravnbøl, Camilla Ida
This paper adds a perspective to existing research on child protection by engaging in a debate on intersectional discrimination and its relationship to child protection. The paper has a twofold objective, (1) to further establish intersectionality as a concept to address discrimination against ch...... children, and (2) to illustrate the importance of addressing intersectionality within rights-based programmes of child protection....
Deburring small intersecting holes
Energy Technology Data Exchange (ETDEWEB)
Gillespie, L.K.
1980-08-01
Deburring intersecting holes is one of the most difficult deburring tasks faced by many industries. Only 14 of the 37 major deburring processes are applicable to most intersecting hole applications. Only five of these are normally applicable to small or miniature holes. Basic process capabilities and techniques used as a function of hole sizes and intersection depths are summarized.
Polygonal instabilities on interfacial vorticities
Labousse, Matthieu
2015-01-01
We report the results of a theoretical investigation of the stability of a toroidal vortex bound by an interface. Two distinct instability mechanisms are identified that rely on, respectively, surface tension and fluid inertia, either of which may prompt the transformation from a circular to a polygonal torus. Our results are discussed in the context of three experiments, a toroidal vortex ring, the hydraulic jump, and the hydraulic bump.
Polygon Exploration with Discrete Vision
Fekete, Sandor P
2008-01-01
With the advent of autonomous robots with two- and three-dimensional scanning capabilities, classical visibility-based exploration methods from computational geometry have gained in practical importance. However, real-life laser scanning of useful accuracy does not allow the robot to scan continuously while in motion; instead, it has to stop each time it surveys its environment. This requirement was studied by Fekete, Klein and Nuechter for the subproblem of looking around a corner, but until now has not been considered in an online setting for whole polygonal regions. We give the first algorithmic results for this important algorithmic problem that combines stationary art gallery-type aspects with watchman-type issues in an online scenario: We demonstrate that even for orthoconvex polygons, a competitive strategy can be achieved only for limited aspect ratio A (the ratio of the maximum and minimum edge length of the polygon), i.e., for a given lower bound on the size of an edge; we give a matching upper boun...
Monotonic Allocation Schemes in Clan Games
Voorneveld, M.; Tijs, S.H.; Grahn, S.
2000-01-01
Total clan games are characterized using monotonicity, veto power of the clan members, and a concavity condition reflecting the decreasing marginal contribution of non-clan members to growing coalitions.This decreasing marginal contribution is incorporated in the notion of a bi-monotonic allocation
Monotone models for prediction in data mining
Velikova, M.V.
2006-01-01
This dissertation studies the incorporation of monotonicity constraints as a type of domain knowledge into a data mining process. Monotonicity constraints are enforced at two stages¿data preparation and data modeling. The main contributions of the research are a novel procedure to test the degree of
Monotonic Stable Solutions for Minimum Coloring Games
Hamers, H.J.M.; Miquel, S.; Norde, H.W.
2011-01-01
For the class of minimum coloring games (introduced by Deng et al. (1999)) we investigate the existence of population monotonic allocation schemes (introduced by Sprumont (1990)). We show that a minimum coloring game on a graph G has a population monotonic allocation scheme if and only if G is (P4,
Monotonicity-preserving linear multistep methods
Hundsdorfer, W.; Ruuth, S.J.; Spiteri, R.J.
2002-01-01
In this paper we provide an analysis of monotonicity properties for linear multistep methods. These monotonicity properties include positivity and the diminishing of total variation. We also pay particular attention to related boundedness properties such as the total-variation-bounded (TVB) property
Version Spaces and Generalized Monotone Boolean Functions
J.C. Bioch (Cor); T. Ibaraki
2002-01-01
textabstractWe consider generalized monotone functions f: X --> {0,1} defined for an arbitrary binary relation <= on X by the property x <= y implies f(x) <= f(y). These include the standard monotone (or positive) Boolean functions, regular Boolean functions and other interesting functions as speci
Version Spaces and Generalized Monotone Boolean Functions
J.C. Bioch (Cor); T. Ibaraki
2002-01-01
textabstractWe consider generalized monotone functions f: X --> {0,1} defined for an arbitrary binary relation <= on X by the property x <= y implies f(x) <= f(y). These include the standard monotone (or positive) Boolean functions, regular Boolean functions and other interesting functions as
Monotone Hurwitz numbers in genus zero
Goulden, I P; Novak, Jonathan
2012-01-01
Hurwitz numbers count branched covers of the Riemann sphere with specified ramification data, or equivalently, transitive permutation factorizations in the symmetric group with specified cycle types. Monotone Hurwitz numbers count a restricted subset of the branched covers counted by the Hurwitz numbers, and have arisen in recent work on the the asymptotic expansion of the Harish-Chandra-Itzykson-Zuber integral. In this paper we begin a detailed study of monotone Hurwitz numbers. We prove two results that are reminiscent of those for classical Hurwitz numbers. The first is the monotone join-cut equation, a partial differential equation with initial conditions that characterizes the generating function for monotone Hurwitz numbers in arbitrary genus. The second is our main result, in which we give an explicit formula for monotone Hurwitz numbers in genus zero.
Sequential Stochastic Construction of Random Polygons.
1982-06-10
clearly geerated by notions of the form T (x,y) 1-+ (Xz* * for (x* y C 2" . This notion sends (1.8) into x coo * + y sin *- (p-x coo -y sin ) = 0 Thus Z ...n-1)) . . . 34 2.7. The Joint Density of Z (n) - The Curling Process . . . . . . 40 CHAPTER 3 POLYGON DISTRIBUTIONS...Joint Density of Z (N) of Polygons .. ........ 47 3.4. The Polygon Density In Isotropicp ............ 31 I . .. . .. .. . . . . . .. ... . . . . . , m
Carpinteria salt marsh habitat polygons
Lafferty, Kevin D.; Dunham, Eleca J.; Mancini, Frank T.; Stewart, Tara E.; Hechinger, Ryan F.
2017-01-01
We identified five common habitat types in Carpinteria Salt Marsh: channels, pans (flats), marsh, salt flat and upland. We then drew polygons around each habitat type identified from a registered and orthorectified aerial photograph and created a GIS shapefile. Polygons were ground-truthed in the field. From these habitat polygons, one can use GIS applications to estimate the area of each habitat type in this estuary. These data support the following publications: Kuris, Armand M., et al. "Ecosystem energetic implications of parasite and free-living biomass in three estuaries." Nature 454.7203 (2008): 515-518.Hechinger, Ryan F., Kevin D. Lafferty, Andy P. Dobson, James H. Brown, and Armand M. Kuris. "A common scaling rule for abundance, energetics, and production of parasitic and free-living species." Science 333, no. 6041 (2011): 445-448.Hechinger, Ryan F., Kevin D. Lafferty, John P. McLaughlin, Brian L. Fredensborg, Todd C. Huspeni, Julio Lorda, Parwant K. Sandhu et al. "Food webs including parasites, biomass, body sizes, and life stages for three California/Baja California estuaries." Ecology 92, no. 3 (2011): 791-791.Buck, J.C., Hechinger, R.F., Wood, A.C., Stewart, T.E., Kuris, A.M., and Lafferty, K.D., "Host density increases parasite recruitment but decreases host risk in a snail-trematode system." Manuscript submitted for publication. Lafferty, K.D., Stewart, T.E., and Hechinger, R.F. (in press). Bird distribution surveys at Carpinteria Salt Marsh, California USA, January 2012 to March 2013: U.S. Geological Survey data release, http://dx.doi.org/10.5066/F7F47M95.
Farthest-Polygon Voronoi Diagrams
Cheong, Otfried; Glisse, Marc; Gudmundsson, Joachim; Hornus, Samuel; Lazard, Sylvain; Lee, Mira; Na, Hyeon-Suk
2010-01-01
Given a family of k disjoint connected polygonal sites in general position and of total complexity n, we consider the farthest-site Voronoi diagram of these sites, where the distance to a site is the distance to a closest point on it. We show that the complexity of this diagram is O(n), and give an O(n log^3 n) time algorithm to compute it. We also prove a number of structural properties of this diagram. In particular, a Voronoi region may consist of k-1 connected components, but if one component is bounded, then it is equal to the entire region.
Polygons on a rotating fluid surface
DEFF Research Database (Denmark)
Jansson, Thomas R.N.; Haspang, Martin P.; Jensen, Kåre H.;
2006-01-01
rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating...
Viable harvest of monotone bioeconomic models
De Lara, Michel; Cabrera, Hector Ramirez
2009-01-01
Some monospecies age class models, as well as specific multi-species models (with so-called technical interactions), exhibit useful monotonicity properties. This paper deals with discrete time monotone bioeconomics dynamics in the presence of state and control constraints. In practice, these latter ``acceptable configurations'' represent production and preservation requirements to be satisfied for all time, and they also possess monotonicity properties. A state $\\state$ is said to belong to the viability kernel if there exists a trajectory, of states and controls, starting from $\\state$ and satisfying the constraints. Under monotonicity assumptions, we present upper and lower estimates of the viability kernel. This helps delineating domains where a viable management is possible. Numerical examples, in the context of fisheries management, for the Chilean sea bass (\\emph{Dissostichus eleginoides}) and Alfonsino (\\emph{Beryx splendens}) are given.
Hyperbolic monotonicity in the Hilbert ball
Directory of Open Access Journals (Sweden)
Reich Simeon
2006-01-01
Full Text Available We first characterize -monotone mappings on the Hilbert ball by using their resolvents and then study the asymptotic behavior of compositions and convex combinations of these resolvents.
Nonlinear regimes on polygonal hydraulic jumps
Rojas, Nicolas
2016-11-01
This work extends previous leading and higher order results on the polygonal hydraulic jump in the framework of inertial lubrication theory. The rotation of steady polygonal jumps is observed in the transition from one wavenumber to the next one, induced by a change in height of an external obstacle near the outer edge. In a previous publication, the study of stationary polygons is considered under the assumption that the reference frame rotates with the polygons when the number of corners change, in order to preserve their orientation. In this research work I provide a Hamiltonian approach and the stability analysis of the nonlinear oscillator that describe the polygonal structures at the jump interface, in addition to a perturbation method that enables to explain, for instance, the diversity of patterns found in experiments. GRASP, Institute of Physics, University of Liege, Belgium.
Institute of Scientific and Technical Information of China (English)
Wu Yang YU; Dong Hua WU; Gang Song LENG
2007-01-01
The purpose of this paper is to generalize the notion of intersection bodies to that of quasi Lp-intersection bodies. The Lp-analogs of the Busemann intersection inequality and the Brunn Minkowski inequality for the quasi Lp-intersection bodies are obtained. The Aleksandrov-Fenchel inequality for the mixed quasi Lp-intersection bodies is also established.
INTERSECTIONAL DISCRIMINATION AGAINST CHILDREN
DEFF Research Database (Denmark)
Ravnbøl, Camilla Ida
This paper adds a perspective to existing research on child protection by engaging in a debate on intersectional discrimination and its relationship to child protection. The paper has a twofold objective, (1) to further establish intersectionality as a concept to address discrimination against...
Tight Bounds for Beacon-Based Coverage in Simple Rectilinear Polygons
Bae, Sang Won
2016-03-21
We establish tight bounds for beacon-based coverage problems. In particular, we show that $$\\\\lfloor \\\\frac{n}{6} \\ floor $$⌊n6⌋ beacons are always sufficient and sometimes necessary to cover a simple rectilinear polygon P with n vertices. When P is monotone and rectilinear, we prove that this bound becomes $$\\\\lfloor \\\\frac{n+4}{8} \\ floor $$⌊n+48⌋. We also present an optimal linear-time algorithm for computing the beacon kernel of P.
Degenerate polygonal tilings in simple animal tissues
Ziherl, Primoz; Hocevar, Ana
2009-03-01
We study 2D polygonal tilings as models of the en-face structure of single-layer biological tissues. Using numerical simulations, we explore the phase diagram of equilibrium tilings of equal-area, equal-perimeter convex polygons whose energy is independent of their shape. We identify 3 distinct phases, which are all observed in simple epithelial tissues: The disordered phase of polygons with 4-9 sides, the hexatic phase, and the hexagonal phase with perfect 6-fold coordination. We quantify their structure using Edwards' statistical mechanics of cellular systems.
Optimal Polygonal Representation of Planar Graphs
Duncan, Christian A; Hu, Yifan; Kaufmann, Michael; Kobourov, Stephen G
2011-01-01
In this paper, we consider the problem of representing graphs by polygons whose sides touch. We show that at least six sides per polygon are necessary by constructing a class of planar graphs that cannot be represented by pentagons. We also show that the lower bound of six sides is matched by an upper bound of six sides with a linear-time algorithm for representing any planar graph by touching hexagons. Moreover, our algorithm produces convex polygons with edges having at most three slopes and with all vertices lying on an O(n)xO(n) grid.
Monotone Rank and Separations in Computational Complexity
Li, Yang D
2011-01-01
In the paper, we introduce the concept of monotone rank, and using it as a powerful tool, we obtain several important and strong separation results in computational complexity. We show a super-exponential separation between monotone and non-monotone computation in the non-commutative model, and thus give the answer to a longstanding open problem posed by Nisan \\cite{Nis1991} in algebraic complexity. More specifically, we exhibit a homogeneous algebraic function $f$ of degree $d$ ($d$ even) on $n$ variables with the monotone algebraic branching program (ABP) complexity $\\Omega(n^{d/2})$ and the non-monotone ABP complexity $O(d^2)$. We propose a relaxed version of the famous Bell's theorem\\cite{Bel1964}\\cite{CHSH1969}. Bell's theorem basically states that local hidden variable theory cannot predict the correlations produced by quantum mechanics, and therefore is an impossibility result. Bell's theorem heavily relies on the diversity of the measurements. We prove that even if we fix the measurement, infinite amo...
Federal Geographic Data Committee — The SMA implementation is comprised of one feature dataset, with several polygon feature classes, rather than a single feature class. SurfaceManagementAgency: The...
The monotonic and fatigue behavior of CFCCs
Energy Technology Data Exchange (ETDEWEB)
Miriyala, N.; Liaw, P.K.; McHargue, C.J. [Univ. of Tennessee, Knoxville, TN (United States); Snead, L.L. [Oak Ridge National Laboratory, TN (United States)
1996-04-01
Flexure tests were performed to study the fabric orientation effects on the monotonic and fatigue behavior of two commercially available continuous fiber reinforced ceramic composites (CFCCs), namely (i) Nicalon fiber fabric reinforced alumina (Al{sub 2}O{sub 3}) matrix composite fabricated by a direct molten metal oxidation (DIMOX) process and, (ii) Nicalon fiber fabric reinforced silicon carbide (SiC) matrix composite fabricated by an isothermal chemical vapor infiltration (ICVI) process. The fabric orientation effects on the monotonic and fatigue behavior were strong in the Nicalon/Al{sub 2}O{sub 3} composite, while they were relatively weak in the Nicalon/SiC composite.
Weighted monotonicity inequalities for unbounded operators
Hoa, Dinh Trung
2011-01-01
Let $\\tau$ be a faithful normal semifinite trace on a von Neumann algebra $\\mathcal{M}$. For a continuous nonnegative convex monotone nondecreasing function $f$ on convex subset $\\Omega$ of $\\mathbb{R}$ and weight nonnegative Borel function $w$ we consider weighted monotonicity inequalities of the form {equation*} \\tau(w(A)^{1/2}f(A)w(A)^{1/2}) \\le \\tau (w(A)^{1/2}f(B)w(A)^{1/2}), {equation*} where $A$ and $B$ are unbounded operators affiliated with respect to algebra $\\mathcal{M}$.
Louisiana ESI: PARISH (Parish Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains boundaries for parishes in coastal Louisiana. Vector polygons in this data set represent parish management areas. Location-specific type and...
Region 9 NPL Sites (Superfund Sites) Polygons
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
Louisiana ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for reptiles and amphibians in coastal Louisiana. Vector polygons represent reptile and amphibian habitats,...
Alabama ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Alabama. The...
Southeast Alaska ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for estuarine, benthic, and pelagic fish in Southeast Alaska. Vector polygons in this data set represent locations of...
Columbia River ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species in Columbia River. Vector polygons in this...
Virginia ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains boundaries for management areas, national parks, state and local parks, and wildlife refuges in Virginia. Vector polygons in this data set...
Western Alaska ESI: HABITATS (Habitat Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for submerged aquatic vegetation (SAV) in Western Alaska. Vector polygons in this data set represent...
Virginia ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Virginia. The...
Maryland ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Maryland. The...
American Samoa ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for reef, pelagic, benthic, and estuarine fish species in American Samoa. Vector polygons in this data set...
Comic image understanding based on polygon detection
Li, Luyuan; Wang, Yongtao; Tang, Zhi; Liu, Dong
2013-01-01
Comic image understanding aims to automatically decompose scanned comic page images into storyboards and then identify the reading order of them, which is the key technique to produce digital comic documents that are suitable for reading on mobile devices. In this paper, we propose a novel comic image understanding method based on polygon detection. First, we segment a comic page images into storyboards by finding the polygonal enclosing box of each storyboard. Then, each storyboard can be represented by a polygon, and the reading order of them is determined by analyzing the relative geometric relationship between each pair of polygons. The proposed method is tested on 2000 comic images from ten printed comic series, and the experimental results demonstrate that it works well on different types of comic images.
Region 9 NPL Site (Polygons) 2015
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
Region 9 NPL Site Polygons - 2014
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
Hawaii ESI: HYDRO (Hydrology Polygons and Lines)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector arcs and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Hawaii. The...
Maryland ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles, estuarine turtles, and rare reptiles and amphibians in Maryland. Vector polygons in this...
Southeast Alaska ESI: BIRDS (Bird Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for waterfowl in Southeast Alaska. Vector polygons in this data set represent locations of foraging and rafting...
Hawaii ESI: HABITATS (Habitat and Plant Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for corals, algae, seagrass, and native/rare terrestrial plants in coastal Hawaii. Vector polygons in this...
Columbia River ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive human-use data for Wildlife Refuges, National Forests, and State Parks for the Columbia River area. Vector polygons in this data set...
American Samoa ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for estuarine, reef-associated, and terrestrial invertebrate species in American Samoa. Vector polygons in...
Columbia River ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Columbia River ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for clams, oysters, crabs, and other invertebrate species in Columbia River. Vector polygons in this data...
American Samoa ESI: BIRDS (Bird Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabirds, wading birds, shorebirds, waterfowl, and gulls and terns in American Samoa. Vector polygons...
American Samoa ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Western Alaska ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine and estuarine invertebrate species in Western Alaska. Vector polygons in this data set represent...
Southeast Alaska ESI: MGT (Management Area Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains management area data for National Parks, Wildlife Refuges, and areas designated as Critical Habitat in Southeast Alaska. Vector polygons in...
From Newton's bucket to rotating polygons
DEFF Research Database (Denmark)
Bach, B.; Linnartz, E. C.; Vested, Malene Louise Hovgaard;
2014-01-01
We present an experimental study of 'polygons' forming on the free surface of a swirling water flow in a partially filled cylindrical container. In our set-up, we rotate the bottom plate and the cylinder wall with separate motors. We thereby vary rotation rate and shear strength independently...... the phase diagram spanned by the two rotational frequencies at a given water filling height and find polygons in a regime, where the two frequencies are sufficiently different and, predominantly, when they have opposite signs. In addition to the extension of the family of polygons found with the stationary...... cylinder, we find a new family of smaller polygons for larger rotation rates of the cylinder, opposite to that of the bottom plate. Further, we find a 'monogon', a figure with one corner, roughly an eccentric circle rotating in the same sense as the cylinder. The case where only the bottom plate...
Western Alaska ESI: HYDRO (Land Mass Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing coastal hydrography that defines the primary land masses used in the creation of the Environmental Sensitivity...
Louisiana ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for coastal...
Louisiana ESI: HABITATS (Habitat and Plant Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for coastal habitats in Louisiana. Vector polygons represent various habitats, including marsh types, other...
Aldazabal, G; Ibáñez, L E; Rabadan, Raul; Uranga, Angel M
2001-01-01
It is known that chiral fermions naturally appear at certain intersections of branes at angles. Motivated by this fact, we propose a string scenario in which different standard model gauge interactions propagate on different (intersecting) brane worlds, partially wrapped in the extra dimensions. Quarks and leptons live at brane intersections, and are thus located at different positions in the extra dimensions. Replication of families follows naturally from the fact that the branes generically intersect at several points. Gauge and Yukawa couplings can be computed in terms of the compactification radii. Hierarchical Yukawa couplings appear naturally, since amplitudes involving three different intersections are proportional to exp(-A_{ijk}), where A_{ijk} is the area of a string world-sheet extending among the intersections. The models are non-supersymmetric but the string scale may be lowered down to 1-10 TeV. The proton is however stable due to a set of discrete symmetries arising from world-sheet selection r...
Anisotropic rectangular metric for polygonal surface remeshing
Pellenard, Bertrand
2013-06-18
We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangle-shaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity.
Monotone Comparative Statics for the Industry Composition
DEFF Research Database (Denmark)
Laugesen, Anders Rosenstand
2015-01-01
We let heterogeneous firms face decisions on a number of complementary activities in a monopolistically-competitive industry. The endogenous level of competition and selection regarding entry and exit of firms introduces a wedge between monotone comparative statics (MCS) at the firm level and MCS...
On a Monotone Ill-posed Problem
Institute of Scientific and Technical Information of China (English)
Nguyen BUONG
2005-01-01
A class of a posteriori parameter choice strategies for the operator version of Tikhonovregularization (including variants of Morozov's and Arcangeli's methods) is proposed and used in investigating the rate of convergence of the regularized solution for ill-posed nonlinear equation involving a monotone operator in Banach space.
Population Monotonic Path Schemes for Simple Games
Ciftci, B.B.; Borm, P.E.M.; Hamers, H.J.M.
2006-01-01
A path scheme for a simple game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path.A path scheme is called population monotonic if a player's payoff does not decrease as the pa
Monotone method for nonlinear nonlocal hyperbolic problems
Directory of Open Access Journals (Sweden)
Azmy S. Ackleh
2003-02-01
Full Text Available We present recent results concerning the application of the monotone method for studying existence and uniqueness of solutions to general first-order nonlinear nonlocal hyperbolic problems. The limitations of comparison principles for such nonlocal problems are discussed. To overcome these limitations, we introduce new definitions for upper and lower solutions.
Limit points of the monotonic schemes
Salomon, J
2005-01-01
Many numerical simulations in quantum (bilinear) control use the monotonically convergent algorithms of Krotov (introduced by Tannor), Zhu & Rabitz or the general form of Maday & Turinici. This paper presents an analysis of the limit set of controls provided by these algorithms and a proof of convergence in a particular case.
REGULAR RELATIONS AND MONOTONE NORMAL ORDERED SPACES
Institute of Scientific and Technical Information of China (English)
XU XIAOQUAN; LIU YINGMING
2004-01-01
In this paper the classical theorem of Zareckii about regular relations is generalized and an intrinsic characterization of regularity is obtained. Based on the generalized Zareckii theorem and the intrinsic characterization of regularity, the authors give a characterization of monotone normality of ordered spaces. A new proof of the UrysohnNachbin lemma is presented which is quite different from the classical one.
Monotonicity and bounds on Bessel functions
Directory of Open Access Journals (Sweden)
Larry Landau
2000-07-01
Full Text Available survey my recent results on monotonicity with respect to order of general Bessel functions, which follow from a new identity and lead to best possible uniform bounds. Application may be made to the "spreading of the wave packet" for a free quantum particle on a lattice and to estimates for perturbative expansions.
Strong monotonicity for analytic ordinary differential equations
Directory of Open Access Journals (Sweden)
Sebastian Walcher
2009-09-01
Full Text Available We present a necessary and sufficient criterion for the flow of an analytic ordinary differential equation to be strongly monotone; equivalently, strongly order-preserving. The criterion is given in terms of the reducibility set of the derivative of the right-hand side. Some applications to systems relevant in biology and ecology, including nonlinear compartmental systems, are discussed.
A monotonic archive for pareto-coevolution.
de Jong, Edwin D
2007-01-01
Coevolution has already produced promising results, but its dynamic evaluation can lead to a variety of problems that prevent most algorithms from progressing monotonically. An important open question therefore is how progress towards a chosen solution concept can be achieved. A general solution concept for coevolution is obtained by viewing opponents or tests as objectives. In this setup known as Pareto-coevolution, the desired solution is the Pareto-optimal set. We present an archive that guarantees monotonicity for this solution concept. The algorithm is called the Incremental Pareto-Coevolution Archive (IPCA), and is based on Evolutionary Multi-Objective Optimization (EMOO). By virtue of its monotonicity, IPCA avoids regress even when combined with a highly explorative generator. This capacity is demonstrated on a challenging test problem requiring both exploration and reliability. IPCA maintains a highly specific selection of tests, but the size of the test archive nonetheless grows unboundedly. We therefore furthermore investigate how archive sizes may be limited while still providing approximate reliability. The LAyered Pareto-Coevolution Archive (LAPCA) maintains a limited number of layers of candidate solutions and tests, and thereby permits a trade-off between archive size and reliability. The algorithm is compared in experiments, and found to be more efficient than IPCA. The work demonstrates how the approximation of a monotonic algorithm can lead to algorithms that are sufficiently reliable in practice while offering better efficiency.
Limit properties of monotone matrix functions
Behrndt, Jussi; Hassi, Seppo; de Snoo, Henk; Wietsma, Rudi
2012-01-01
The basic objects in this paper are monotonically nondecreasing n x n matrix functions D(center dot) defined on some open interval l = (a, b) of R and their limit values D(a) and D(b) at the endpoints a and b which are, in general, selfadjoint relations in C-n. Certain space decompositions induced b
Concerns on Monotonic Imbalance Bounding Matching Methods
Yatracos, Yannis G.
2013-01-01
Concerns are expressed for the Monotonic Imbalance Bounding (MIB) property (Iacus et al. 2011) and for MIB matching because i) the definition of the MIB property leads to inconsistencies and the nature of the imbalance measure is not clearly defined, ii) MIB property does not generalize Equal Percent Bias Reducing (EPBR) property, iii) MIB matching does not provide statistical information available with EPBR matching.
Nonparametric confidence intervals for monotone functions
Groeneboom, P.; Jongbloed, G.
2015-01-01
We study nonparametric isotonic confidence intervals for monotone functions. In [Ann. Statist. 29 (2001) 1699–1731], pointwise confidence intervals, based on likelihood ratio tests using the restricted and unrestricted MLE in the current status model, are introduced. We extend the method to the trea
Competitive learning of monotone Boolean functions
2014-01-01
We apply competitive analysis onto the problem of minimizing the number of queries to an oracle to completely reconstruct a given monotone Boolean function. Besides lower and upper bounds on the competitivity we determine optimal deterministic online algorithms for the smallest problem instances.
Nonparametric confidence intervals for monotone functions
Groeneboom, P.; Jongbloed, G.
2015-01-01
We study nonparametric isotonic confidence intervals for monotone functions. In [Ann. Statist. 29 (2001) 1699–1731], pointwise confidence intervals, based on likelihood ratio tests using the restricted and unrestricted MLE in the current status model, are introduced. We extend the method to the
Edit Distance to Monotonicity in Sliding Windows
DEFF Research Database (Denmark)
Chan, Ho-Leung; Lam, Tak-Wah; Lee, Lap Kei
2011-01-01
of a data stream is becoming well-understood over the past few years. Motivated by applications on network quality monitoring, we extend the study to estimating the edit distance to monotonicity of a sliding window covering the w most recent items in the stream for any w ≥ 1. We give a deterministic...
New concurrent iterative methods with monotonic convergence
Energy Technology Data Exchange (ETDEWEB)
Yao, Qingchuan [Michigan State Univ., East Lansing, MI (United States)
1996-12-31
This paper proposes the new concurrent iterative methods without using any derivatives for finding all zeros of polynomials simultaneously. The new methods are of monotonic convergence for both simple and multiple real-zeros of polynomials and are quadratically convergent. The corresponding accelerated concurrent iterative methods are obtained too. The new methods are good candidates for the application in solving symmetric eigenproblems.
Classification Trees for Problems with Monotonicity Constraints
R. Potharst (Rob); A.J. Feelders
2002-01-01
textabstractFor classification problems with ordinal attributes very often the class attribute should increase with each or some of the explaining attributes. These are called classification problems with monotonicity constraints. Classical decision tree algorithms such as CART or C4.5 generally do
Ewertowski, Marek W.; Kijowski, Andrzej; Szuman, Izabela; Tomczyk, Aleksandra M.; Kasprzak, Leszek
2017-09-01
The examination of low-altitude aerial photographs reveals the presence of more than 400 polygonal nets in central western Poland. Polygons range from 5 to almost 70 m in diameter. Based on the polygons' diameter and intersection angles, we identified seven main types of nets geometry. Based on ground verification, we interpreted them as past thermal-contraction-cracks, filled mostly with sand (i.e. sand-wedge casts). As favourable weather conditions and a proper land cover (i.e. cultivated land) are necessary for identifying polygonal nets, the observed number of polygons is probably much underestimated. The broad occurrence of former thermal-contraction-cracks' polygons indicates that continuous permafrost was widespread in central western Poland after the termination of the Last Glacial Maximum (LGM). Preliminary dating of the cracks' infilling as well as polygon geometry suggest that thermal-contraction-cracking occurred in several different phases and that a time frame of a few thousand years is sufficient to form complex, mature nets.
Evolving fracture patterns: columnar joints, mud cracks, and polygonal terrain
Goehring, L.
2012-12-01
Contraction cracks can form captivating patterns, such as the artistic craquelure sometimes found in pottery glazes, to the cracks in dried mud, or the polygonal networks covering the polar regions of Earth and Mars. Two types are frequently encountered: those with irregular rectilinear patterns, such as that formed by an homogeneous slurry when dried (or cooled) uniformly, and more regular hexagonal patterns, such as those typified by columnar joints. Once cracks start to form in a thin contracting layer, they will sequentially break the layer into smaller and smaller pieces. A rectilinear crack pattern encodes information about the order of cracks, as later cracks tend to intersect with earlier cracks at right angles. In this manner they relieve the stresses perpendicular to the pre-existing crack. In a hexagonal pattern, in contrast, the angles between all cracks at a vertex are near 120°. In this presentation it will be shown how both types of pattern can arise from identical forces, and that a rectilinear, T-junction dominated pattern will develop into to a hexagonal pattern, with Y-junctions, if allowed to. Such an evolution can be explained as the result of three conditions: (1) if cracks advance through space, or heal and recur, that the previous positions of a crack tip acts as a line of weakness, guiding the next iteration of cracking; (2) that the order of opening of cracks can change in each iteration; and (3) that crack tips curve to maximise the local strain energy release rate. The ordering of crack patterns are seen in a number of systems: columnar joints in starch and lava; desiccation cracks in clays that are repeatedly wetted and dried; cracks in eroding gypsum-cemented sand layers; and the cracks in permafrost known as polygonal terrain. These patterns will each be briefly explored, in turn, and shown to obey the above principles of crack pattern evolution.
Wilson loop remainder function for null polygons in the limit of self-crossing
Dorn, Harald
2011-01-01
The remainder function of Wilson loops for null polygons becomes divergent if two vertices approach each other. We apply RG techniques to the limiting configuration of a contour with self-intersection. As a result for the two loop remainder we find a quadratic divergence in the logarithm of the distance between the two approaching vertices. The divergence is multiplied by a factor, which is given by a pure number plus the product of two logarithms of cross-ratios characterising the conformal geometry of the self-crossing.
CERN PhotoLab
1974-01-01
The experimental apparatus used at intersection 1 by the CERN-Bologna Collaboration (experiment R105). It consists of two almost identical magnetic spectrometers centered at 90 degrees on opposite sides of the intersection region. In each spectrometer one can see magnetostrictive wire spark chambers, a magnet, more chambers and various hodoscopes of scintillation counters. Gas Cerenkov counters (almost invisible in the picture) are located in the gap of each magnet. On the left hand side, a matrix of 119 lead glass Cerenkov counters is located behind some concrete and iron shielding.
Monotone operators and "bigger conjugate" functions
Bauschke, Heinz H; Wang, Xianfu; Yao, Liangjin
2011-01-01
We study a question posed by Stephen Simons in his 2008 monograph involving "bigger conjugate" (BC) functions and the partial infimal convolution. As Simons demonstrated in his monograph, these function have been crucial to the understanding and advancement of the state-of-the-art of harder problems in monotone operator theory, especially the sum problem. In this paper, we provide some tools for further analysis of BC--functions which allow us to answer Simons' problem in the negative. We are also able to refute a similar but much harder conjecture which would have generalized a classical result of Br\\'ezis, Crandall and Pazy. Our work also reinforces the importance of understanding unbounded skew linear relations to construct monotone operators with unexpected properties.
Convex functions, monotone operators and differentiability
Phelps, Robert R
1993-01-01
The improved and expanded second edition contains expositions of some major results which have been obtained in the years since the 1st edition. Theaffirmative answer by Preiss of the decades old question of whether a Banachspace with an equivalent Gateaux differentiable norm is a weak Asplund space. The startlingly simple proof by Simons of Rockafellar's fundamental maximal monotonicity theorem for subdifferentials of convex functions. The exciting new version of the useful Borwein-Preiss smooth variational principle due to Godefroy, Deville and Zizler. The material is accessible to students who have had a course in Functional Analysis; indeed, the first edition has been used in numerous graduate seminars. Starting with convex functions on the line, it leads to interconnected topics in convexity, differentiability and subdifferentiability of convex functions in Banach spaces, generic continuity of monotone operators, geometry of Banach spaces and the Radon-Nikodym property, convex analysis, variational princ...
Complexity of Non-Monotonic Logics
Thomas, Michael
2010-01-01
Over the past few decades, non-monotonic reasoning has developed to be one of the most important topics in computational logic and artificial intelligence. Different ways to introduce non-monotonic aspects to classical logic have been considered, e.g., extension with default rules, extension with modal belief operators, or modification of the semantics. In this survey we consider a logical formalism from each of the above possibilities, namely Reiter's default logic, Moore's autoepistemic logic and McCarthy's circumscription. Additionally, we consider abduction, where one is not interested in inferences from a given knowledge base but in computing possible explanations for an observation with respect to a given knowledge base. Complexity results for different reasoning tasks for propositional variants of these logics have been studied already in the nineties. In recent years, however, a renewed interest in complexity issues can be observed. One current focal approach is to consider parameterized problems and ...
Linear Inviscid Damping for Monotone Shear Flows
Zillinger, Christian
2014-01-01
In this article we prove linear stability, inviscid damping and scattering of the 2D Euler equations around regular, strictly monotone shear flows $(U(y),0)$ in a periodic channel under Sobolev perturbations. We treat the settings of an infinite channel, $\\mathbb{T} \\times \\mathbb{R}$, as well as a finite channel, $\\mathbb{T} \\times [0,1]$, with impermeable boundary. We first prove inviscid damping with optimal algebraic rates for strictly monotone shear flows under the assumption of controlling the regularity of the scattered vorticity. Subsequently, we establish linear stability of the scattering equation in Sobolev spaces under perturbations which are of not too large wave-length with respect to $x$, depending on $U''$.
Sassenroth, Cynthia; Hauber, Ernst; Schmitz, Nicole; de Vera, Jean Pierre
2017-04-01
Polygonally fractured ground is widespread at middle and high latitudes on Mars. The latitude-dependence and the morphologic similarity to terrestrial patterned ground in permafrost regions may indicate a formation as thermal contraction cracks, but the exact formation mechanisms are still unclear. In particular, it is debated whether freeze-thaw processes and liquid water are required to generate the observed features. This study quantitatively investigates polygonal networks in ice-free parts of continental Antarctica to help distinguishing between different hypotheses of their origin on Mars. The study site is located in the Helliwell Hills in Northern Victoria Land ( 71.73°S/161.38°E) and was visited in the framework of the GANOVEX XI expedition during the austral summer of 2015/2016. The local bedrock consists mostly of sediments (sandstones) of the Beacon Supergroup and mafic igneous intrusions (Ferrar Dolerites). The surfaces are covered by glacial drift consisting of clasts with diverse lithologies. Thermal contraction cracks are ubiquitous. We mapped polygons in the northern part of Helliwell Hills in a GIS environment on the basis of high-resolution satellite images with a pixel size of 50 cm. The measured spatial parameters include polygon area, perimeter, length, width, circularity and aspect. We also analyzed the connectivity of enclosed polygons within a polygon network. The polygons do not display significant local relief, but overall the polygon centers are slightly higher than the bounding cracks (i.e. high-center polygons). Sizes of polygons can vary widely, dependent on the geographical location, between 10m2 and >900m2. In planar and level areas, thermal contraction cracks tend to be well connected as hexagonal or irregular polygonal networks without a preferred alignment. In contrast, polygonal networks on slopes form elongated, orthogonal primary cracks, which are either parallel or transverse to the steepest topographic gradient. During
Improved selection in totally monotone arrays
Energy Technology Data Exchange (ETDEWEB)
Mansour, Y. (Harvard Univ., Cambridge, MA (United States). Aiken Computation Lab.); Park, J.K. (Sandia National Labs., Albuquerque, NM (United States)); Schieber, B. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center); Sen, S. (AT and T Bell Labs., Murray Hill, NJ (United States))
1991-01-01
This paper's main result is an O(({radical}{bar m}lgm)(n lg n) + mlg n)-time algorithm for computing the kth smallest entry in each row of an m {times} n totally monotone array. (A two-dimensional A = a(i,j) is totally monotone if for all i{sub 1} < i{sub 2} and j{sub 1} < j{sup 2}, < a(i{sub 1},j{sub 2}) implies a(i{sub 2},j{sub 1})). For large values of k (in particular, for k=(n/2)), this algorithm is significantly faster than the O(k(m+n))-time algorithm for the same problem due to Kravets and Park. An immediate consequence of this result is an O(n{sup 3/2} lg{sup 2}n)-time algorithm for computing the kth nearest neighbor of each vertex of a convex n-gon. In addition to the main result, we also give an O(n lg m)-time algorithm for computing an approximate median in each row of an m {times} n totally monotone array; this approximate median is an entry whose rank in its row lies between (n/4) and (3n/4) {minus} 1. 20 refs., 3 figs.
Edit Distance to Monotonicity in Sliding Windows
Chan, Ho-Leung; Lee, Lap-Kei; Pan, Jiangwei; Ting, Hing-Fung; Zhang, Qin
2011-01-01
Given a stream of items each associated with a numerical value, its edit distance to monotonicity is the minimum number of items to remove so that the remaining items are non-decreasing with respect to the numerical value. The space complexity of estimating the edit distance to monotonicity of a data stream is becoming well-understood over the past few years. Motivated by applications on network quality monitoring, we extend the study to estimating the edit distance to monotonicity of a sliding window covering the $w$ most recent items in the stream for any $w \\ge 1$. We give a deterministic algorithm which can return an estimate within a factor of $(4+\\eps)$ using $O(\\frac{1}{\\eps^2} \\log^2(\\eps w))$ space. We also extend the study in two directions. First, we consider a stream where each item is associated with a value from a partial ordered set. We give a randomized $(4+\\epsilon)$-approximate algorithm using $O(\\frac{1}{\\epsilon^2} \\log \\epsilon^2 w \\log w)$ space. Second, we consider an out-of-order strea...
CERN PhotoLab
1971-01-01
Intersection I-1 of the ISR in August 1971 showing the 90 degree large acceptance spectrometer of the Saclay-Strasbourg Collaboration which is studying the momentum spectra of electrons at large angles. On the left of the crossing region can be seen the track used by the CERN-Bucharest-Cracow-Tata Collaboration to bring nuclear emulsions into the ISR.
1971-01-01
Intersection I-2 of the ISR during the installation of experiments. On the left to the crossing region can be seen the massive iron plate structure of the muon detector being used by a British collaboration in a search for the intermediate vector boson. The magnet and hodoscopes on the right are part of the spectrometer arm of the Bristish-Scandinavian Collaration.
Intersectional embodiment and power
DEFF Research Database (Denmark)
Elg, Camilla; Jensen, Sune Qvotrup
Through almost two decades the term ‘intersectionality' has gained influence in post colonial studies, gender studies, feminist theory and other research fields occupied with how social differences are distributed and how individuals are socially constructed in stratified societies. The ‘interse...... differences and discuss the implications this has for our understanding of power relations....
Equipartitioning and balancing points of polygons
Directory of Open Access Journals (Sweden)
Shunmugam Pillay
2010-07-01
Full Text Available The centre of mass G of a triangle has the property that the rays to the vertices from G sweep out triangles having equal areas. We show that such points, termed equipartitioning points in this paper, need not exist in other polygons. A necessary and sufficient condition for a quadrilateral to have an equipartitioning point is that one of its diagonals bisects the other. The general theorem, namely, necessary and sufficient conditions for equipartitioning points for arbitrary polygons to exist, is also stated and proved. When this happens, they are in general, distinct from the centre of mass. In parallelograms, and only in them, do the two points coincide.
Weak monotonicity inequality and partial regularity for harmonic maps
Institute of Scientific and Technical Information of China (English)
沈尧天; 严树森
1999-01-01
The notion of locally weak monotonicity inequality for weakly harmonic maps is introduced and various results on this class of maps are obtained. For example, the locally weak monotonicity inequality is nearly equivalent to the ε-regularity.
Monotonic Loading of Circular Surface Footings on Clay
DEFF Research Database (Denmark)
Ibsen, Lars Bo; Barari, Amin
2011-01-01
Appropriate modeling of offshore foundations under monotonic loading is a significant challenge in geotechnical engineering. This paper reports experimental and numerical analyses, specifically investigating the response of circular surface footings during monotonic loading and elastoplastic beha...
Random packing of regular polygons and star polygons on a flat two-dimensional surface.
Cieśla, Michał; Barbasz, Jakub
2014-08-01
Random packing of unoriented regular polygons and star polygons on a two-dimensional flat continuous surface is studied numerically using random sequential adsorption algorithm. Obtained results are analyzed to determine the saturated random packing ratio as well as its density autocorrelation function. Additionally, the kinetics of packing growth and available surface function are measured. In general, stars give lower packing ratios than polygons, but when the number of vertexes is large enough, both shapes approach disks and, therefore, properties of their packing reproduce already known results for disks.
Directory of Open Access Journals (Sweden)
Ioan Halalae
2015-07-01
Full Text Available Computational Geometry is currently using approximation techniques based on convex polygons, with good results in some topics, but with severe limitation of applicability. In this paper we present the first step of a larger project, aiming to lead us to the plane projection of a 3D surface obtained by intersecting two cylinders (a very frequent problem in obtaining the stencils for welded ensembles. As a first step, we present an algorithm for experimentally obtaining the intersection curve of two cylinders. The new paradigm and also the fundamentally new aspect of our project is that we construct our algorithm by simulation of the analytical relations describing the curve, and not by approximation using convex polygons.
Crash patterns at signalized intersections
Polders, Evelien; Daniels, Stijn; HERMANS, Elke; Brijs, Tom; Wets, Geert
2015-01-01
Traffic signals are often implemented to provide for efficient movement and to improve traffic safety. Nevertheless, severe crashes still occur at signalized intersections. This study aims to improve the understanding of signalized intersection safety by identifying crash types, locations and factors associated with signalized intersections. For this purpose, 1295 police-reported crashes at 87 signalized intersections are analyzed based on detailed crash descriptions, i.e. crash data and c...
A-monotonicity and applications to nonlinear variational inclusion problems
Directory of Open Access Journals (Sweden)
Ram U. Verma
2004-01-01
Full Text Available A new notion of the A-monotonicity is introduced, which generalizes the H-monotonicity. Since the A-monotonicity originates from hemivariational inequalities, and hemivariational inequalities are connected with nonconvex energy functions, it turns out to be a useful tool proving the existence of solutions of nonconvex constrained problems as well.
On the strong monotonicity of the CABARET scheme
Ostapenko, V. V.
2012-03-01
The strong monotonicity of the CABARET scheme with single flux correction is analyzed as applied to the linear advection equation. It is shown that the scheme is strongly monotone (has the NED property) at Courant numbers r ∈ (0,0,5), for which it is monotone. Test computations illustrating this property of the CABARET scheme are presented.
Testing Manifest Monotonicity Using Order-Constrained Statistical Inference
Tijmstra, Jesper; Hessen, David J.; van der Heijden, Peter G. M.; Sijtsma, Klaas
2013-01-01
Most dichotomous item response models share the assumption of latent monotonicity, which states that the probability of a positive response to an item is a nondecreasing function of a latent variable intended to be measured. Latent monotonicity cannot be evaluated directly, but it implies manifest monotonicity across a variety of observed scores,…
Polygon cluster pattern recognition based on new visual distance
Shuai, Yun; Shuai, Haiyan; Ni, Lin
2007-06-01
The pattern recognition of polygon clusters is a most attention-getting problem in spatial data mining. The paper carries through a research on this problem, based on spatial cognition principle and visual recognition Gestalt principle combining with spatial clustering method, and creates two innovations: First, the paper carries through a great improvement to the concept---"visual distance". In the definition of this concept, not only are Euclid's Distance, orientation difference and dimension discrepancy comprehensively thought out, but also is "similarity degree of object shape" crucially considered. In the calculation of "visual distance", the distance calculation model is built using Delaunay Triangulation geometrical structure. Second, the research adopts spatial clustering analysis based on MST Tree. In the design of pruning algorithm, the study initiates data automatism delamination mechanism and introduces Simulated Annealing Optimization Algorithm. This study provides a new research thread for GIS development, namely, GIS is an intersection principle, whose research method should be open and diverse. Any mature technology of other relative principles can be introduced into the study of GIS, but, they need to be improved on technical measures according to the principles of GIS as "spatial cognition science". Only to do this, can GIS develop forward on a higher and stronger plane.
Sequential and Parallel Algorithms for Finding a Maximum Convex Polygon
DEFF Research Database (Denmark)
Fischer, Paul
1997-01-01
such a polygon which is maximal with respect to area can be found in time O(n³ log n). With the same running time one can also find such a polygon which contains a maximum number of positive points. If, in addition, the number of vertices of the polygon is restricted to be at most M, then the running time...
SRB Measures for Polygonal Billiards with Contracting Reflection Laws
Del Magno, Gianluigi; Lopes Dias, João; Duarte, Pedro; Gaivão, José Pedro; Pinheiro, Diogo
2014-07-01
We prove that polygonal billiards with contracting reflection laws exhibit hyperbolic attractors with countably many ergodic SRB measures. These measures are robust under small perturbations of the reflection law, and the tables for which they exist form a generic set in the space of all convex polygons. Specific polygonal tables are studied in detail.
Fair Partitions of Polygons: An Elementary Introduction
Indian Academy of Sciences (India)
R Nandakumar; N Ramana Rao
2012-08-01
We introduce the question: Given a positive integer , can any 2D convex polygonal region be partitioned into convex pieces such that all pieces have the same area and the same perimeter? The answer to this question is easily `yes’ for =2. We give an elementary proof that the answer is `yes’ for =4 and generalize it to higher powers of 2.
Polygon Subtraction in 2 or 3 Dimensions
Energy Technology Data Exchange (ETDEWEB)
Wilson, John E.
2013-10-01
When searching for computer code to perform the ubiquitous task of subtracting one polygon from another, it is difficult to find real examples and detailed explanations. This paper outlines the step-by-step process necessary to accomplish this basic task.
A characterization of quasi-rational polygons
Bedaride, Nicolas
2012-11-01
The aim of this paper is to study quasi-rational polygons related to the outer billiard. We compare different notions introduced in Gutkin and Simányi (1992 Commun. Math. Phys. 143 431-49) and Schwartz (2009 Outer Billiards on Kites (Annals of Mathematics Studies vol 171) (Princeton, NJ: Princeton University Press)) and make a synthesis of them.
Wehrl entropy, Lieb conjecture and entanglement monotones
Mintert, F; Mintert, Florian; Zyczkowski, Karol
2004-01-01
We propose to quantify the entanglement of pure states of $N \\times N$ bipartite quantum system by defining its Husimi distribution with respect to $SU(N)\\times SU(N)$ coherent states. The Wehrl entropy is minimal if and only if the pure state analyzed is separable. The excess of the Wehrl entropy is shown to be equal to the subentropy of the mixed state obtained by partial trace of the bipartite pure state. This quantity, as well as the generalized (R{\\'e}nyi) subentropies, are proved to be Schur--convex, so they are entanglement monotones and may be used as alternative measures of entanglement.
Intersectional embodiment and power
DEFF Research Database (Denmark)
Elg, Camilla; Jensen, Sune Qvotrup
. The ‘intersectional' perspective creates a focus on the coexistence and mutual formation of different kinds of social difference in the construction of the individual social position. The concept of habitus as it was coined by Pierre Bourdieu has been an inspiration for some of this research. However, the focus...... on the embodiment of social dispositions and the social formation of the individual as body inherent in Bourdieu's work have not yet gained weight in this development within ‘difference research'. It might not come to much surprise as the radical sociology of embodiment implicit in the theory of habitus does...... not seem to gain much attention in social stratification research in general. In our paper we will present our work on an embodied approach to intersectionality, which is inspired by Pierre Bourdieu and other thinkers of embodiment. We will argue for the importance of a focus on the embodiment of social...
Chen, C M; Sharakin, S A; Chen, Chiang-Mei; Gal'tsov, Dmitri V.; Sharakin, Sergei A.
1999-01-01
New solution to the six-dimensional vacuum Einstein's equations is constructed as a non-linear superposition of two five-dimensional solutions representing the Melvin-Gibbons-Maeda Universe and its S-dual. Then using duality between D=8 vacuum and a certain class of D=11 supergravity configurations we generate M2 and M5 fluxbranes as well as some of their intersections also including waves and KK-monopoles.
Topological recursion and a quantum curve for monotone Hurwitz numbers
Do, Norman; Dyer, Alastair; Mathews, Daniel V.
2017-10-01
Classical Hurwitz numbers count branched covers of the Riemann sphere with prescribed ramification data, or equivalently, factorisations in the symmetric group with prescribed cycle structure data. Monotone Hurwitz numbers restrict the enumeration by imposing a further monotonicity condition on such factorisations. In this paper, we prove that monotone Hurwitz numbers arise from the topological recursion of Eynard and Orantin applied to a particular spectral curve. We furthermore derive a quantum curve for monotone Hurwitz numbers. These results extend the collection of enumerative problems known to be governed by the paradigm of topological recursion and quantum curves, as well as the list of analogues between monotone Hurwitz numbers and their classical counterparts.
The Monotonicity Puzzle: An Experimental Investigation of Incentive Structures
Directory of Open Access Journals (Sweden)
Jeannette Brosig
2010-05-01
Full Text Available Non-monotone incentive structures, which - according to theory - are able to induce optimal behavior, are often regarded as empirically less relevant for labor relationships. We compare the performance of a theoretically optimal non-monotone contract with a monotone one under controlled laboratory conditions. Implementing some features relevant to real-world employment relationships, our paper demonstrates that, in fact, the frequency of income-maximizing decisions made by agents is higher under the monotone contract. Although this observed behavior does not change the superiority of the non-monotone contract for principals, they do not choose this contract type in a significant way. This is what we call the monotonicity puzzle. Detailed investigations of decisions provide a clue for solving the puzzle and a possible explanation for the popularity of monotone contracts.
Convex functions, monotone operators and differentiability
Phelps, Robert R
1989-01-01
These notes start with an introduction to the differentiability of convex functions on Banach spaces, leading to the study of Asplund spaces and their intriguing relationship to monotone operators (and more general set-values maps) and Banach spaces with the Radon-Nikodym property. While much of this is classical, some of it is presented using streamlined proofs which were not available until recently. Considerable attention is paid to contemporary results on variational principles and perturbed optimization in Banach spaces, exhibiting their close connections with Asplund spaces. An introductory course in functional analysis is adequate background for reading these notes which can serve as the basis for a seminar of a one-term graduate course. There are numerous excercises, many of which form an integral part of the exposition.
Generalized convexity, generalized monotonicity recent results
Martinez-Legaz, Juan-Enrique; Volle, Michel
1998-01-01
A function is convex if its epigraph is convex. This geometrical structure has very strong implications in terms of continuity and differentiability. Separation theorems lead to optimality conditions and duality for convex problems. A function is quasiconvex if its lower level sets are convex. Here again, the geo metrical structure of the level sets implies some continuity and differentiability properties for quasiconvex functions. Optimality conditions and duality can be derived for optimization problems involving such functions as well. Over a period of about fifty years, quasiconvex and other generalized convex functions have been considered in a variety of fields including economies, man agement science, engineering, probability and applied sciences in accordance with the need of particular applications. During the last twenty-five years, an increase of research activities in this field has been witnessed. More recently generalized monotonicity of maps has been studied. It relates to generalized conve...
The cohomology ring of polygon spaces
Hausmann, J C; Hausmann, Jean-Claude; Knutson, Allen
1997-01-01
We compute the integer cohomology rings of the ``polygon spaces'' introduced in [Hausmann,Klyachko,Kapovich-Millson]. This is done by embedding them in certain toric varieties; the restriction map on cohomology is surjective and we calculate its kernel using ideas from the theory of Gröbner bases. Since we do not invert the prime 2, we can tensor with Z/2; halving all degrees we show this produces the Z/2 cohomology rings of planar polygon spaces. In the equilateral case, where there is an action of the symmetric group permuting the edges, we show that the induced action on the integer cohomology is _not_ the standard one, despite it being so on the rational cohomology [Kl]. Finally, our formulae for the Poincaré polynomials are more computationally effective than those known [Kl].
A polygonal method for haptic force generation
Energy Technology Data Exchange (ETDEWEB)
Anderson, T. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering]|[Sandia National Labs., Albuquerque, NM (United States)
1996-12-31
Algorithms for computing forces and associated surface deformations (graphical and physical) are given, which, together with a force feedback device can be used to haptically display virtual objects. The Bendable Polygon algorithm, created at Sandia National Labs and the University of New Mexico, for visual rendering of computer generated surfaces is also presented. An implementation using the EIGEN virtual reality environment, and the PHANToM (Trademark) haptic interface, is reported together with suggestions for future research.
Non-convex polygons clustering algorithm
Directory of Open Access Journals (Sweden)
Kruglikov Alexey
2016-01-01
Full Text Available A clustering algorithm is proposed, to be used as a preliminary step in motion planning. It is tightly coupled to the applied problem statement, i.e. uses parameters meaningful only with respect to it. Use of geometrical properties for polygons clustering allows for a better calculation time as opposed to general-purpose algorithms. A special form of map optimized for quick motion planning is constructed as a result.
Searching a Polygonal Region by Two Guards
Institute of Scientific and Technical Information of China (English)
Xue-Hou Tan; Bo Jiang
2008-01-01
We study the problem of searching for a mobile intruder in a polygonal region P by two guards. The objective is to decide whether there should exist a search schedule for the two guards to detect the intruder, no matter how fast the intruder moves, and if so, generate a search schedule. During the search, the two guards are required to walk on the boundary of P continuously and be mutually visible all the time. We present a characterization of the class of polygons searchable by two guards in terms of non-redundant components, and thus solve a long-standing open problem in computational geometry.Also, we give an optimal O(n) time algorithm to determine the two-guard searchability in a polygon, and an O(n log n + m) time algorithm to generate a search schedule, if it exists, where n is the number of vertices of P and m (≤ n2) is the number of search instructions reported.
The Hausdorff core problem on simple polygons
Directory of Open Access Journals (Sweden)
Reza Dorrigiv
2014-02-01
Full Text Available A polygon \\(Q\\ is a \\(k\\-bounded Hausdorff Core of a polygon \\(P\\ if \\(P\\ contains \\(Q\\, \\(Q\\ is convex, and the Hausdorff distance between \\(P\\ and \\(Q\\ is at most \\(k\\. A Hausdorff Core of \\(P\\ is a \\(k\\-bounded Hausdorff Core of \\(P\\ with the minimum possible value of \\(k\\, which we denote \\(k_{\\min}\\. Given any \\(k\\ and any \\(\\varepsilon\\gt 0\\, we describe an algorithm for computing a \\(k'\\-bounded Hausdorff Core (if one exists in \\(O(n^3+n^2\\varepsilon^{-4}(\\log n+ \\varepsilon^{-2}\\ time, where \\(k'\\lt k+d_{\\text{rad}}\\cdot\\varepsilon\\ and \\(d_{\\text{rad}}\\ is the radius of the smallest disc that encloses \\(P\\ and whose center is in \\(P\\. We use this solution to provide an approximation algorithm for the optimization Hausdorff Core problem which results in a solution of size \\(k_{\\min}+d_{\\text{rad}}\\cdot\\varepsilon\\ in \\(O(\\log(\\varepsilon^{-1}(n^3+n^2\\varepsilon^{-4}(\\log n+ \\varepsilon^{-2}\\ time. Finally, we describe an approximation scheme for the \\(k\\-bounded Hausdorff Core problem which, given a polygon \\(P\\, a distance \\(k\\, and any \\(\\varepsilon\\gt 0\\, answers true if there is a \\(((1+\\varepsilonk\\-bounded Hausdorff Core and false if there is no \\(k\\-bounded Hausdorff Core. The running time of the approximation scheme is in \\(O(n^3+n^2\\varepsilon^{-4}(\\log n+ \\varepsilon^{-2}\\.
Matching a statistical pressure snake to a four-sided polygon and estimating the polygon corners.
Energy Technology Data Exchange (ETDEWEB)
Schaub, Hanspeter (ORION International Technologies, Albuquerque, NM); Wilson, Chris C.
2004-05-01
Given a video image source, a statistical pressure snake is able to track a color target in real time. This report presents an algorithm that exploits the one-dimensional nature of the visual snake target outline. If the target resembles a four-sided polygon, then the four polygon sides are identified by mapping all image snake point coordinates into Hough space where lines become points. After establishing that four dominant lines are present in snake contour, the polygon corner points are estimated. The computation burden of this algorithm is of the N logN type. The advantage of this method is that it can provide real-time target corner estimates, even if the corners themselves might be occluded.
Stability of dynamical systems on the role of monotonic and non-monotonic Lyapunov functions
Michel, Anthony N; Liu, Derong
2015-01-01
The second edition of this textbook provides a single source for the analysis of system models represented by continuous-time and discrete-time, finite-dimensional and infinite-dimensional, and continuous and discontinuous dynamical systems. For these system models, it presents results which comprise the classical Lyapunov stability theory involving monotonic Lyapunov functions, as well as corresponding contemporary stability results involving non-monotonicLyapunov functions.Specific examples from several diverse areas are given to demonstrate the applicability of the developed theory to many important classes of systems, including digital control systems, nonlinear regulator systems, pulse-width-modulated feedback control systems, and artificial neural networks. The authors cover the following four general topics: - Representation and modeling of dynamical systems of the types described above - Presentation of Lyapunov and Lagrange stability theory for dynamical sy...
Stepsize Restrictions for Boundedness and Monotonicity of Multistep Methods
Hundsdorfer, W.
2011-04-29
In this paper nonlinear monotonicity and boundedness properties are analyzed for linear multistep methods. We focus on methods which satisfy a weaker boundedness condition than strict monotonicity for arbitrary starting values. In this way, many linear multistep methods of practical interest are included in the theory. Moreover, it will be shown that for such methods monotonicity can still be valid with suitable Runge-Kutta starting procedures. Restrictions on the stepsizes are derived that are not only sufficient but also necessary for these boundedness and monotonicity properties. © 2011 Springer Science+Business Media, LLC.
On the monotonicity of multidimensional finite difference schemes
Kovyrkina, O.; Ostapenko, V.
2016-10-01
The classical concept of monotonicity, introduced by Godunov for linear one-dimensional difference schemes, is extended to multidimensional case. Necessary and sufficient conditions of monotonicity are obtained for linear multidimensional difference schemes of first order. The constraints on the numerical viscosity are given that ensure the monotonicity of a difference scheme in the multidimensional case. It is proposed a modification of the second order multidimensional CABARET scheme that preserves the monotonicity of one-dimensional discrete solutions and, as a result, ensures higher smoothness in the computation of multidimensional discontinuous solutions. The results of two-dimensional test computations illustrating the advantages of the modified CABARET scheme are presented.
Polygons in restricted geometries subjected to infinite forces
Beaton, N. R.; Eng, J. W.; Soteros, C. E.
2016-10-01
We consider self-avoiding polygons in a restricted geometry, namely an infinite L × M tube in {{{Z}}}3. These polygons are subjected to a force f, parallel to the infinite axis of the tube. When f\\gt 0 the force stretches the polygons, while when f\\lt 0 the force is compressive. We obtain and prove the asymptotic form of the free energy in both limits f\\to +/- ∞ . We conjecture that the f\\to -∞ asymptote is the same as the limiting free energy of ‘Hamiltonian’ polygons, polygons which visit every vertex in a L× M× N box. We investigate such polygons, and in particular use a transfer-matrix methodology to establish that the conjecture is true for some small tube sizes. Dedicated to Anthony J Guttmann on the occasion of his 70th birthday.
Conversion of raster coded images to polygonal data structures
Nichols, D. A.
1982-01-01
A method is presented for converting polygons coded in raster data structures into conventional vector structures to allow the output of scanner-based data collection systems to be input directly to conventional geographic information systems. The method relies on topological principles to (1) uniquely label each polygon in the image and produce an output image in which each pixel is described by the label of the polygon to which it belongs; (2) create line segment components of polygon boundaries, with nodes labeled and the two adjacent polygons identified; and (3) traverse the polygon boundaries by connecting the appropriate adjacent line segments. The conversion capability makes it possible to design systems which automatically convert to the data structure most appropriate for a particular application.
Polygon Morphing and Its Application in Orebody Modeling
Directory of Open Access Journals (Sweden)
Hacer İlhan
2012-01-01
Full Text Available Three different polygon morphing methods are examined. The first one is based on the utilization of the trimmed skeleton of the symmetric difference of the source and target polygons as an intermediate polygon. The second one reduces the problem to the problem of morphing compatible planar triangulations and utilizes the representation of planar triangulations as a matrix constructed using barycentric coordinates of the planar triangulation's vertices relative to their neighbors. The third and last one describes the polygon by the parametric curve representation based on estimated Fourier parameters and thus transfers the morphing process to Fourier parametric space. The different features and comparative results of these methods are shown by the tests with different examples. These methods are used for generating a set of polygonal sections from two nonplanar polygonal sections which are nearly planar in 3D before constructing a three-dimensional object from these nonplanar sections.
格网划分的双策略跟踪多边形裁剪算法%Polygon clipping algorithm based on dual-strategies tracing and grid partition
Institute of Scientific and Technical Information of China (English)
汪荣峰; 廖学军
2012-01-01
An effective algorithm for polygon clipping which supports simple polygons including concave polygons and polygons with holes inside is presented in this paper. This algorithm can be used to calculate set-theoretic differences and union of two polygons. Most analogous algorithms are classifying point of intersection by entry points and exit points, then generating output polygons by tracing vertex. Different from these algorithms, this paper classifies point of intersection by normal point of intersection and vertex of intersection, and designs different tracing strategies for them. By using these strategies alternately and recursively, a steady tracing process to cope with degenerate input is putted forward. To improve efficiency of edge intersection, which is the bottleneck of polygon clipping, it partitions the polygon that has more numbers of edges to grids and brings forward an algorithm for edge partition based on Bresenham line-drawing algorithm. At the end of this paper, the algorithm is compared with the existing algorithms and the result shows that it has higher speed than others.%论文提出了一种高效稳定的多边形裁剪算法,算法支持带内环的平面简单多边形,同时也支持多边形的“并”和“差”等布尔运算.首先,设计了算法所需的数据结构；其次,基于直线扫描转换Bresenham算法原理提出了边网格划分的有效算法,并应用一个简单的方法避免不同网格内边的重复求交；最后,将交点分类为普通交点和顶交点,并针对这两类交点构造了不同的跟踪策略,在跟踪过程中交替、递归地应用这两个策略来确保算法处理特殊情况时的稳定性.与其它同类算法的比较表明,新算法具有更高的效率.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In this paper, by using the Brunn-Minkowski-Firey mixed volume theory and dual mixed volume theory, associated with Lp intersection body and dual mixed volume, some dual Brunn-Minkowski inequalities and their isolate forms are established for Lp intersection body about the normalized Lp radial addition and Lp radial linear combination. Some properties of operator Lp are given.
INEQUALITIES FOR MIXED INTERSECTION BODIES
Institute of Scientific and Technical Information of China (English)
YUAN SHUFENG; LENG GANGSONG
2005-01-01
In this paper, some properties of mixed intersection bodies are given, and inequalities from the dual Brunn-Minkowski theory (such as the dual Minkowski inequality, the dual Aleksandrov-Fenchel inequalities and the. dual Brunn-Minkowski inequalities) are established for mixed intersection bodies.
Study of CNC Grinding Machining Method About Isometric Polygon Profile
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The formed principle and CNC grinding machining method of isometric polygonal profile are studied deeply and systematically. Equation about section curve of isometric polygon profile is set up by means of geometric principle. With the use of differential geometry theory, the curve is proved to be with geometric feature of convex curve. It is referred to as Isometric Polygonal Curve (IPC), because that is a kind of convex curve on which the distance between any parallel tangent lines is equal. Isometric Poly...
Preparation Of Control Space For Remeshing Of Polygonal Surfaces
Tomasz Jurczyk; Barbara Glut
2013-01-01
The subject of the article concerns the issues of remeshing, transforming a polygonal mesh into a triangular mesh adapted to surface. From the initial polygonal mesh the curvature of surface and boundary is retrieved and used to calculate a metric tensor varying in three-dimensional space. In the proposed approach the curvature is computed using local approximation of surfaces and curves on the basis of vertices of the polygonal mesh. An essential part of the presented remeshing procedure is...
Monotone measures of ergodicity for Markov chains
Directory of Open Access Journals (Sweden)
J. Keilson
1998-01-01
Full Text Available The following paper, first written in 1974, was never published other than as part of an internal research series. Its lack of publication is unrelated to the merits of the paper and the paper is of current importance by virtue of its relation to the relaxation time. A systematic discussion is provided of the approach of a finite Markov chain to ergodicity by proving the monotonicity of an important set of norms, each measures of egodicity, whether or not time reversibility is present. The paper is of particular interest because the discussion of the relaxation time of a finite Markov chain [2] has only been clean for time reversible chains, a small subset of the chains of interest. This restriction is not present here. Indeed, a new relaxation time quoted quantifies the relaxation time for all finite ergodic chains (cf. the discussion of Q1(t below Equation (1.7]. This relaxation time was developed by Keilson with A. Roy in his thesis [6], yet to be published.
Remarks on a monotone Markov chain
Directory of Open Access Journals (Sweden)
P. Todorovic
1987-01-01
Full Text Available In applications, considerations on stochastic models often involve a Markov chain {ζn}0∞ with state space in R+, and a transition probability Q. For each x R+ the support of Q(x,. is [0,x]. This implies that ζ0≥ζ1≥…. Under certain regularity assumptions on Q we show that Qn(x,Bu→1 as n→∞ for all u>0 and that 1−Qn(x,Bu≤[1−Q(x,Bu]n where Bu=[0,u. Set τ0=max{k;ζk=ζ0}, τn=max{k;ζk=ζτn−1+1} and write Xn=ζτn−1+1, Tn=τn−τn−1. We investigate some properties of the imbedded Markov chain {Xn}0∞ and of {Tn}0∞. We determine all the marginal distributions of {Tn}0∞ and show that it is asymptotically stationary and that it possesses a monotonicity property. We also prove that under some mild regularity assumptions on β(x=1−Q(x,Bx, ∑1n(Ti−a/bn→dZ∼N(0,1.
Natural convection in polygonal enclosures with inner circular cylinder
Directory of Open Access Journals (Sweden)
Habibis Saleh
2015-12-01
Full Text Available This study investigates the natural convection induced by a temperature difference between cold outer polygonal enclosure and hot inner circular cylinder. The governing equations are solved numerically using built-in finite element method of COMSOL. The governing parameters considered are the number of polygonal sides, aspect ratio, radiation parameter, and Rayleigh number. We found that the number of contra-rotative cells depended on polygonal shapes. The convection heat transfer becomes constant at L / D > 0 . 77 and the polygonal shapes are no longer sensitive to the Nusselt number profile.
Perceptions and Expected Immediate Reactions to Tornado Warning Polygons
Lindell, M. K.; Huang, S. K.; Wei, H. L.; Samuelson, C. D.
2015-12-01
To provide people with more specific information about tornado threats, the National Weather Service has replaced its county-wide warnings with smaller warning polygons that more specifically indicate the risk area. However, tornado warning polygons do not have a standardized definition regarding tornado strike probabilities (ps) so it is unclear how warning recipients interpret them. To better understand this issue, 155 participants responded to 15 hypothetical warning polygons. After viewing each polygon, they rated the likelihood of a tornado striking their location and the likelihood that they would take nine different response actions ranging from continuing normal activities to getting in a car and driving somewhere safer. The results showed participants inferred that the ps was highest at the polygon's centroid, lower just inside the edges of the polygon, still lower (but not zero) just outside the edges of the polygon, and lowest in locations beyond that. Moreover, higher ps values were associated with lower expectations of continuing normal activities and higher expectations of seeking information from social sources (but not environmental cues) and higher expectations of seeking shelter (but not evacuating in their cars). These results indicate that most people make some errors in their ps judgments but are likely to respond appropriately to the ps they infer from the warning polygons. Overall, the findings from this study and other research can help meteorologists to better understand how people interpret the uncertainty associated with warning polygons and, thus, improve tornado warning systems.
Robust Monotone Iterates for Nonlinear Singularly Perturbed Boundary Value Problems
Directory of Open Access Journals (Sweden)
Boglaev Igor
2009-01-01
Full Text Available This paper is concerned with solving nonlinear singularly perturbed boundary value problems. Robust monotone iterates for solving nonlinear difference scheme are constructed. Uniform convergence of the monotone methods is investigated, and convergence rates are estimated. Numerical experiments complement the theoretical results.
Regularization and Iterative Methods for Monotone Variational Inequalities
Directory of Open Access Journals (Sweden)
Xiubin Xu
2010-01-01
Full Text Available We provide a general regularization method for monotone variational inequalities, where the regularizer is a Lipschitz continuous and strongly monotone operator. We also introduce an iterative method as discretization of the regularization method. We prove that both regularization and iterative methods converge in norm.
LIMITED MEMORY BFGS METHOD FOR NONLINEAR MONOTONE EQUATIONS
Institute of Scientific and Technical Information of China (English)
Weijun Zhou; Donghui Li
2007-01-01
In this paper, we propose an algorithm for solving nonlinear monotone equations by combining the limited memory BFGS method (L-BFGS) with a projection method. We show that the method is globally convergent if the equation involves a Lipschitz continuous monotone function. We also present some preliminary numerical results.
Positivity and Monotonicity Preserving Biquartic Rational Interpolation Spline Surface
Directory of Open Access Journals (Sweden)
Xinru Liu
2014-01-01
Full Text Available A biquartic rational interpolation spline surface over rectangular domain is constructed in this paper, which includes the classical bicubic Coons surface as a special case. Sufficient conditions for generating shape preserving interpolation splines for positive or monotonic surface data are deduced. The given numeric experiments show our method can deal with surface construction from positive or monotonic data effectively.
Constrained Geodesic Centers of a Simple Polygon
Oh, Eunjin; Son, Wanbin; Ahn, Hee-Kap
2016-01-01
For any two points in a simple polygon P, the geodesic distance between them is the length of the shortest path contained in P that connects them. A geodesic center of a set S of sites (points) with respect to P is a point in P that minimizes the geodesic distance to its farthest site. In many realistic facility location problems, however, the facilities are constrained to lie in feasible regions. In this paper, we show how to compute the geodesic centers constrained to a set of line segment...
-Mixed Intersection Bodies and Star Duality
Indian Academy of Sciences (India)
Zhao Chang-jian; Wing-Sum Cheung
2010-09-01
The paper extends the two notions of the dual mixed volumes and -intersection body to -dual mixed volumes and -mixed intersection body, respectively. Inequalities for the star dual of -mixed intersection bodies are established.
Monotone complete C*-algebras and generic dynamics
Saitô, Kazuyuki
2015-01-01
This monograph is about monotone complete C*-algebras, their properties and the new classification theory. A self-contained introduction to generic dynamics is also included because of its important connections to these algebras. Our knowledge and understanding of monotone complete C*-algebras has been transformed in recent years. This is a very exciting stage in their development, with much discovered but with many mysteries to unravel. This book is intended to encourage graduate students and working mathematicians to attack some of these difficult questions. Each bounded, upward directed net of real numbers has a limit. Monotone complete algebras of operators have a similar property. In particular, every von Neumann algebra is monotone complete but the converse is false. Written by major contributors to this field, Monotone Complete C*-algebras and Generic Dynamics takes readers from the basics to recent advances. The prerequisites are a grounding in functional analysis, some point set topology and an eleme...
Modelling of urban traffic networkof signalized intersections
2013-01-01
This report presents how traffic network of signalized intersection in a chosen urban area called Tema is synchronized. Using a modular approach, two different types of traffic intersection commonly found in an urban area were modelled i.e. a simple intersection and a complex intersection. A direct road, even though not an intersection, was also included in the modelling because it’s commonly found in an urban area plus it connects any two intersections. Each of these scenarios was modelled u...
Intersectional perspective in elderly care
Directory of Open Access Journals (Sweden)
Marta Cuesta
2016-05-01
Full Text Available Earlier research has shown that power relationships at workplaces are constructed by power structures. Processes related to power always influence the working conditions for (in this study in elderly care the working groups involved. Power structures are central for intersectional analysis, in the sense that the intersectional perspective highlights aspects such as gender and ethnicity (subjective dimensions and interrelates them to processes of power (objective dimension. This qualitative study aims to explore in what way an intersectional perspective could contribute to increased knowledge of power structures in a nursing home where the employees were mostly immigrants from different countries. By using reflexive dialogues related to an intersectional perspective, new knowledge which contributes to the employees’ well-being could develop. Narrative analysis was the method used to conduct this study. Through a multi-stage focus group on six occasions over 6 months, the staff were engaged in intersectional and critical reflections about power relationship with the researchers, by identifying patterns in their professional activities that could be connected to their subjectivities (gender, ethnicity, etc.. The result of this study presents three themes that express the staff's experiences and connect these experiences to structural discrimination. 1 Intersectionality, knowledge, and experiences of professionalism; 2 Intersectionality, knowledge, and experiences of collaboration; and 3 Intersectionality, knowledge, and experiences of discrimination. The result demonstrates that an intersectional perspective reinforces the involved abilities, during the conversations, into being clear about, for example, their experiences of discrimination, and consequently developing a better understanding of their professionalism and collaboration. Such deeper reflections became possible through a process of consciousness raising, strengthening the employee
a Distributed Polygon Retrieval Algorithm Using Mapreduce
Guo, Q.; Palanisamy, B.; Karimi, H. A.
2015-07-01
The burst of large-scale spatial terrain data due to the proliferation of data acquisition devices like 3D laser scanners poses challenges to spatial data analysis and computation. Among many spatial analyses and computations, polygon retrieval is a fundamental operation which is often performed under real-time constraints. However, existing sequential algorithms fail to meet this demand for larger sizes of terrain data. Motivated by the MapReduce programming model, a well-adopted large-scale parallel data processing technique, we present a MapReduce-based polygon retrieval algorithm designed with the objective of reducing the IO and CPU loads of spatial data processing. By indexing the data based on a quad-tree approach, a significant amount of unneeded data is filtered in the filtering stage and it reduces the IO overhead. The indexed data also facilitates querying the relationship between the terrain data and query area in shorter time. The results of the experiments performed in our Hadoop cluster demonstrate that our algorithm performs significantly better than the existing distributed algorithms.
A DISTRIBUTED POLYGON RETRIEVAL ALGORITHM USING MAPREDUCE
Directory of Open Access Journals (Sweden)
Q. Guo
2015-07-01
Full Text Available The burst of large-scale spatial terrain data due to the proliferation of data acquisition devices like 3D laser scanners poses challenges to spatial data analysis and computation. Among many spatial analyses and computations, polygon retrieval is a fundamental operation which is often performed under real-time constraints. However, existing sequential algorithms fail to meet this demand for larger sizes of terrain data. Motivated by the MapReduce programming model, a well-adopted large-scale parallel data processing technique, we present a MapReduce-based polygon retrieval algorithm designed with the objective of reducing the IO and CPU loads of spatial data processing. By indexing the data based on a quad-tree approach, a significant amount of unneeded data is filtered in the filtering stage and it reduces the IO overhead. The indexed data also facilitates querying the relationship between the terrain data and query area in shorter time. The results of the experiments performed in our Hadoop cluster demonstrate that our algorithm performs significantly better than the existing distributed algorithms.
Lifescience Database Archive (English)
Full Text Available List Contact us BodyParts3D Polygon mesh data (Polygon reduction rate = 99% IS-A Tree) Data detail Data name... Polygon mesh data (Polygon reduction rate = 99% IS-A Tree) DOI 10.18908/lsdba.nbdc00837-007 Description of ...data contents BodyParts3D organ model data with the polygon reduction rate of 99%. The zip-compressed downlo... Policy | Contact Us Polygon mesh data (Polygon reduction rate = 99% IS-A Tree) - BodyParts3D | LSDB Archive ...
Lifescience Database Archive (English)
Full Text Available List Contact us BodyParts3D Polygon mesh data (Polygon reduction rate = 99% PART-OF Tree) Data detail Data n...ame Polygon mesh data (Polygon reduction rate = 99% PART-OF Tree) DOI 10.18908/lsdba.nbdc00837-008 Descripti...on of data contents BodyParts3D organ model data with the polygon reduction rate of 99%. The zip-compressed ...tabase Site Policy | Contact Us Polygon mesh data (Polygon reduction rate = 99% PART-OF Tree) - BodyParts3D | LSDB Archive ...
The geometry of inner spanning trees for planar polygons
Energy Technology Data Exchange (ETDEWEB)
Ivanov, Alexandr O; Tuzhilin, Alexey A [P.G. Demidov Yaroslavl State University, Yaroslavl (Russian Federation)
2012-04-30
We study the geometry of minimal inner spanning trees for planar polygons (that is, spanning trees whose edge-intervals lie in these polygons). We construct analogues of Voronoi diagrams and Delaunay triangulations, prove that every minimal inner spanning tree is a subgraph of an appropriate Delaunay triangulation, and describe the possible structure of the cells of such triangulations.
Distributed algorithm for controlling scaled-free polygonal formations
Garcia de Marina Peinado, Hector; Jayawardhana, Bayu; Cao, Ming
2017-01-01
This paper presents a distributed algorithm for controlling the deployment of a team of agents in order to form a broad class of polygons, including regular ones, where each agent occupies a corner of the polygon. The algorithm shares the properties from the popular distance- based rigid formation c
EDGE REMOVAL OF 3D POLYGONAL MODEL USING MAYA API
Directory of Open Access Journals (Sweden)
SAMEER ARORA
2010-09-01
Full Text Available In various applications of computer graphics, 3D polygonal modeling is used, which consists millions of triangular polygon. In this polygon attributes – vertices, edges and faces’ details are to be stored. In order to control the processing time, storing space, and transfer speed, it is often required to reduce the information ofthese polygonal 3D models. In this paper an effort is made to reduce the number of edges. There are various methods to reduce faces and edges of these 3D models. A C++ dynamic link library as Maya Plugin has been created to remove number of edges of 3D triangular polygon model using the Quadric Error Metrics (QEM in MAYA v2010 x64 API. QEM allows fast and accurate geometric simplification of 3D models.
The Number of Monotone and Self-Dual Boolean Functions
Directory of Open Access Journals (Sweden)
Haviarova L.
2014-12-01
Full Text Available In the present paper we study properties of pre-complete class of Boolean functions - monotone Boolean functions. We discuss interval graph, the abbreviated d.n.f., a minimal d.n.f. and a shortest d.n.f. of this function. Then we present a d.n.f. with the highest number of conjunctionsand we determinate the exact number of them. We count the number of monotone Boolean functions with some special properties. In the end we estimate the number of Boolean functionthat are monotone and self-dual at the same time.
Ratio Monotonicity of Polynomials Derived from Nondecreasing Sequences
Chen, William Y C; Zhou, Elaine L F
2010-01-01
The ratio monotonicity of a polynomial is a stronger property than log-concavity. Let P(x) be a polynomial with nonnegative and nondecreasing coefficients. We prove the ratio monotone property of P(x+1), which leads to the log-concavity of P(x+c) for any $c\\geq 1$ due to Llamas and Mart\\'{\\i}nez-Bernal. As a consequence, we obtain the ratio monotonicity of the Boros-Moll polynomials obtained by Chen and Xia without resorting to the recurrence relations of the coefficients.
GPU加速的多边形叠加分析%Accelerating polygon overlay analysis by GPU
Institute of Scientific and Technical Information of China (English)
赵斯思; 周成虎
2013-01-01
叠加分析是地理信息系统最重要的分析功能之一,对多边形图层进行叠加分析要花费大量时间.为此,将GPU用于多边形叠加分析过程中的MBR过滤及多边形剪裁两个阶段.对MBR过滤阶段,提出了基于GPU的通过直方图及并行前置和实现的MBR过滤算法.对多边形剪裁阶段,通过改进Weiler-Atherton算法,使用新的焦点插入方法和简化的出入点标记算法,并结合并行前置和算法,提出了基于GPU的多边形剪裁算法.对实现过程中可能出现的负载不均衡情况,给出了基于动态规划的负载均衡方法.通过对这些算法的应用,实现对过滤阶段及精炼阶段的加速.实验结果表明,基于GPU的MBR过滤方法相对CPU实现的加速比为3.8,而基于GPU的多边形剪裁的速度比CPU实现快3.4倍.整体上,与CPU实现相比,GPU加速的多边形叠加提供了3倍以上的加速比.%Overlay analysis is one of the most important analysis capabilities of geographic information systems. Overlay analysis with polygon layers is a time-intensive process. To improve time efficiency, modern approaches of overlay analysis are generally divided into two stages, filtering and refinement (also known as polygon clipping). A great deal of effort has been taken to significantly reduce the number of candidates in the first stage (filtering) in order to alleviate the workload of the second stage (refinement). However, the second stage is still the most time-consuming part of the process. In this paper we applied GPGPU (General-purpose Graphics Processing Unit) computing to the two key stages of overlay analysis: MBR filtering (part of the filtering) and polygon clipping, and restricted the search area to polygon intersection analysis. We proposed GPU-based MBR filtering algorithm by combining histogram and parallel prefix-sum algorithms, and introduced GPU-based polygon clipping algorithm by improving Weiler-Atherton algorithm. There are two differences
Generating realistic roofs over a rectilinear polygon
Ahn, Heekap
2011-01-01
Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs, and show a connection with the straight skeleton of P. We show that the maximum possible number of distinct realistic roofs over P is ( ⌊(n-4)/4⌋ (n-4)/2) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n 4) preprocessing time. We also present an O(n 5)-time algorithm for computing a realistic roof with minimum height or volume. © 2011 Springer-Verlag.
Periodic billiard trajectories in polygons: generating mechanisms
Vorobets, Ya B.; Gal'perin, G. A.; Stepin, Anatolii M.
1992-06-01
CONTENTSIntroduction §1. Billiard trajectories in a plane domain §2. Fagnano's problem. Mechanical interpretations of periodic trajectories in triangles §3. An extremal property of billiard trajectories. Birkhoff's theorem. The non-existence of a unified construction of periodic trajectories in obtuse triangles §4. 'Perpendicular' trajectories in obtuse triangles of special shape §5. 'Perpendicular' trajectories in rational polygons and polyhedra §6. Stable trajectories §7. Stable perpendicular trajectories §8. Isolated trajectories §9. Isolated trajectories in acute and obtuse triangles. The bifurcation diagram of isolated trajectories (a 'hang-glider' configuration) §10. The density of F-triangles in a neighbourhood of (0, 0) §11. Generalization of the construction of isolated trajectories in obtuse triangles §12. Stable and unstable billiard trajectories in plane Weyl chambers §13. A criterion for the stability of periodic trajectories in a regular hexagonConclusionReferences
Diffusion-Limited Aggregation with Polygon Particles
Institute of Scientific and Technical Information of China (English)
邓礼; 王延颋; 欧阳钟灿
2012-01-01
Diffusion-limited aggregation (DLA) assumes that particles perform pure random walk at a finite tem- perature and aggregate when they come close enough and stick together. Although it is well known that DLA in two dimensions results in a ramified fractal structure, how the particle shape influences the formed morphology is still un- clear. In this work, we perform the off-lattice two-dimensional DLA simulations with different particle shapes of triangle, quadrangle, pentagon, hexagon, and octagon, respectively, and compare with the results for circular particles. Our results indicate that different particle shapes only change the local structure, but have no effects on the global structure of the formed fractal duster. The local compactness decreases as the number of polygon edges increases.
High speed printing with polygon scan heads
Stutz, Glenn
2016-03-01
To reduce and in many cases eliminate the costs associated with high volume printing of consumer and industrial products, this paper investigates and validates the use of the new generation of high speed pulse on demand (POD) lasers in concert with high speed (HS) polygon scan heads (PSH). Associated costs include consumables such as printing ink and nozzles, provisioning labor, maintenance and repair expense as well as reduction of printing lines due to high through put. Targets that are applicable and investigated include direct printing on plastics, printing on paper/cardboard as well as printing on labels. Market segments would include consumer products (CPG), medical and pharmaceutical products, universal ID (UID), and industrial products. In regards to the POD lasers employed, the wavelengths include UV(355nm), Green (532nm) and IR (1064nm) operating within the repetition range of 180 to 250 KHz.
Directory of Open Access Journals (Sweden)
Plubtieng Somyot
2009-01-01
Full Text Available Abstract We introduce an iterative scheme for finding a common element of the solution set of a maximal monotone operator and the solution set of the variational inequality problem for an inverse strongly-monotone operator in a uniformly smooth and uniformly convex Banach space, and then we prove weak and strong convergence theorems by using the notion of generalized projection. The result presented in this paper extend and improve the corresponding results of Kamimura et al. (2004, and Iiduka and Takahashi (2008. Finally, we apply our convergence theorem to the convex minimization problem, the problem of finding a zero point of a maximal monotone operator and the complementary problem.
Directory of Open Access Journals (Sweden)
Somyot Plubtieng
2009-01-01
Full Text Available We introduce an iterative scheme for finding a common element of the solution set of a maximal monotone operator and the solution set of the variational inequality problem for an inverse strongly-monotone operator in a uniformly smooth and uniformly convex Banach space, and then we prove weak and strong convergence theorems by using the notion of generalized projection. The result presented in this paper extend and improve the corresponding results of Kamimura et al. (2004, and Iiduka and Takahashi (2008. Finally, we apply our convergence theorem to the convex minimization problem, the problem of finding a zero point of a maximal monotone operator and the complementary problem.
On the Monotone Iterative Method for Set Valued Equation
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This paper deals with the monotone iterative method for set- valued operator equation in ordered normed space. Some results for the case of single valued operator are generalized here, as an application, a discontinuous nonlinear differential equation problem is discussed.
Monotone method for initial value problem for fractional diffusion equation
Institute of Scientific and Technical Information of China (English)
ZHANG Shuqin
2006-01-01
Using the method of upper and lower solutions and its associated monotone iterative, consider the existence and uniqueness of solution of an initial value problem for the nonlinear fractional diffusion equation.
Wenrich, M. L.; Christensen, P. R.
The mechanism for the genesis of the polygonal terrains in Acidalia and Utopia Planitia has long been sought: however, no completely satisfying model was put forth that characterizes the evolution of these complexly patterned terrains. The polygons are roughly hexagonal but some are not entirely enclosed by fractures. These polygonal features range in widths from approximately 5 to 20 km. Several origins were proposed that describe the polygon borders as desiccation cracks, columnar jointing in a cooled lava, or frost-wedge features. These tension-induced cracking hypotheses were addressed by Pechmann, who convincingly disputes these mechanisms of formation based on scale magnitude difficulties and morphology. Pechmann suggests instead that the cracks delineating the 5-20-km-wide polygons on the northern plains of Mars are graben resulting from deep-seated, uniform, horizontal tension. The difficulty with this hypothesis is that no analogous polygonal forms are known to have originated by tectonism on Earth. McGill and Hills propose that the polygonal terrains on Mars resulted from either rapid desiccation of sediments or cooling of volcanics coupled with differential compaction of the material over a buried irregular topographic surface. They suggest that fracturing was enhanced over the areas of positive relief and was suppressed above the topographic lows. McGill and Hills suggest that the spacing of the topographic highs primarily controls the size of the Martian polygons and the physics of the shrinkage process is a secondary concern. Ray et. al. conducted a terrestrial study of patterned ground in periglacial areas of the U.S. to determine the process responsible for polygonal ground formation. They developed a model for polygon formation in which convection of seasonal melt water above a permafrost layer, driven by an unstable density stratification, differentially melts the permafrost interface, causing it to become undulatory.
Rectangular Blocks vs Polygonal Walls in Archaeoseismology
Directory of Open Access Journals (Sweden)
Klaus-G. Hinzen
2017-07-01
Full Text Available Collapsed or deformed walls in ancient structures constitute important evidence in archaeoseismology, where damage is interpreted in terms of earthquake ground motion. A large variety of wall types have been developed during the millennia in different cultural backgrounds. Often walls with polygonal-shaped building blocks are regarded as more earthquake-resistant than a wall consisting of rectangular elements and, as is sometimes speculated, that the irregular wall types were intentionally developed for that purpose. We use simply structured discrete element models of four walls with different block geometries, perfect rectangular, an Inka-type structure and two polygonal designs, to test their dynamic behavior. In addition to an analytic calculation of ground motion, we use measured strong motion signals as boundary conditions for the 3D wall models with varying height to width ratios. At peak ground accelerations between 1.0 and 9.0 m/s2 and major frequencies of 0.5 to 3 Hz, numeric experiments with the horizontally applied analytic ground motions result in clear differences in the resistance of the four wall types with the rectangular block wall being most vulnerable. For more complex measured 3D motions the Inka-type wall proves more stable than the rectangular block wall; however, height to width ratio still has equally strong influence on the stability. Internal deformation of non-collapsed walls shows some correlation with the parameters of the driving motion. For simple impulsive ground motions, a peak ground displacement threshold exists between toppling and remaining upright for all four models but peak acceleration cannot be reliably back calculated.
Approximations for Monotone and Non-monotone Submodular Maximization with Knapsack Constraints
Kulik, Ariel; Tamir, Tami
2011-01-01
Submodular maximization generalizes many fundamental problems in discrete optimization, including Max-Cut in directed/undirected graphs, maximum coverage, maximum facility location and marketing over social networks. In this paper we consider the problem of maximizing any submodular function subject to $d$ knapsack constraints, where $d$ is a fixed constant. We establish a strong relation between the discrete problem and its continuous relaxation, obtained through {\\em extension by expectation} of the submodular function. Formally, we show that, for any non-negative submodular function, an $\\alpha$-approximation algorithm for the continuous relaxation implies a randomized $(\\alpha - \\eps)$-approximation algorithm for the discrete problem. We use this relation to improve the best known approximation ratio for the problem to $1/4- \\eps$, for any $\\eps > 0$, and to obtain a nearly optimal $(1-e^{-1}-\\eps)-$approximation ratio for the monotone case, for any $\\eps>0$. We further show that the probabilistic domain ...
Action-Maslov Homomorphism for Monotone Symplectic Manifolds
Branson, Mark
2009-01-01
We explore conditions under which the action-Maslov homomorphism vanishes on monotone symplectic manifolds. Our strategy involves showing that the units in the quantum homology, and thus the Seidel element, have a very specific form. Then we use induction to show that other relevant Gromov-Witten invariants vanish. We prove that these conditions hold for monotone products of projective spaces and for the Grassmannian of 2-planes in $\\C^4$.
Completely monotonic functions related to logarithmic derivatives of entire functions
DEFF Research Database (Denmark)
Pedersen, Henrik Laurberg
2011-01-01
The logarithmic derivative l(x) of an entire function of genus p and having only non-positive zeros is represented in terms of a Stieltjes function. As a consequence, (-1)p(xml(x))(m+p) is a completely monotonic function for all m ≥ 0. This generalizes earlier results on complete monotonicity...... of functions related to Euler's psi-function. Applications to Barnes' multiple gamma functions are given....
Isotonicity of the projection onto the monotone cone
Németh, A B
2012-01-01
A wedge (i.e., a closed nonempty set in the Euclidean space stable under addition and multiplication with non-negative scalars) induces by a standard way a semi-order (a reflexive and transitive binary relation) in the space. The wedges admitting isotone metric projection with respect to the semi-order induced by them are characterized. The obtained result is used to show that the monotone wedge (called monotone cone in regression theory) admits isotone projection.
Monotonic loading of circular surface footings on clay
Energy Technology Data Exchange (ETDEWEB)
Ibsen, Lars Bo; Barari, Amin [Aalborg University, Aalborg (Denmark)
2011-12-15
Appropriate modeling of offshore foundations under monotonic loading is a significant challenge in geotechnical engineering. This paper reports experimental and numerical analyses, specifically investigating the response of circular surface footings during monotonic loading and elastoplastic behavior during reloading. By using the findings presented in this paper, it is possible to extend the model to simulate the vertical-load displacement response of offshore bucket foundations.
Convergence for pseudo monotone semiflows on product ordered topological spaces
Yi, Taishan; Huang, Lihong
In this paper, we consider a class of pseudo monotone semiflows, which only enjoy some weak monotonicity properties and are defined on product-ordered topological spaces. Under certain conditions, several convergence principles are established for each precompact orbit of such a class of semiflows to tend to an equilibrium, which improve and extend some corresponding results already known. Some applications to delay differential equations are presented.
Layered neural networks with non-monotonic transfer functions
Katayama, Katsuki; Sakata, Yasuo; Horiguchi, Tsuyoshi
2003-01-01
We investigate storage capacity and generalization ability for two types of fully connected layered neural networks with non-monotonic transfer functions; random patterns are embedded into the networks by a Hebbian learning rule. One of them is a layered network in which a non-monotonic transfer function of even layers is different from that of odd layers. The other is a layered network with intra-layer connections, in which the non-monotonic transfer function of inter-layer is different from that of intra-layer, and inter-layered neurons and intra-layered neurons are updated alternately. We derive recursion relations for order parameters for those layered networks by the signal-to-noise ratio method. We clarify that the storage capacity and the generalization ability for those layered networks are enhanced in comparison with those with a conventional monotonic transfer function when non-monotonicity of the transfer functions is selected optimally. We also point out that some chaotic behavior appears in the order parameters for the layered networks when non-monotonicity of the transfer functions increases.
Conformal array design on arbitrary polygon surface with transformation optics
Directory of Open Access Journals (Sweden)
Li Deng
2016-06-01
Full Text Available A transformation-optics based method to design a conformal antenna array on an arbitrary polygon surface is proposed and demonstrated in this paper. This conformal antenna array can be adjusted to behave equivalently as a uniformly spaced linear array by applying an appropriate transformation medium. An typical example of general arbitrary polygon conformal arrays, not limited to circular array, is presented, verifying the proposed approach. In summary, the novel arbitrary polygon surface conformal array can be utilized in array synthesis and beam-forming, maintaining all benefits of linear array.
Interpolation Error Estimates for Mean Value Coordinates over Convex Polygons.
Rand, Alexander; Gillette, Andrew; Bajaj, Chandrajit
2013-08-01
In a similar fashion to estimates shown for Harmonic, Wachspress, and Sibson coordinates in [Gillette et al., AiCM, to appear], we prove interpolation error estimates for the mean value coordinates on convex polygons suitable for standard finite element analysis. Our analysis is based on providing a uniform bound on the gradient of the mean value functions for all convex polygons of diameter one satisfying certain simple geometric restrictions. This work makes rigorous an observed practical advantage of the mean value coordinates: unlike Wachspress coordinates, the gradient of the mean value coordinates does not become large as interior angles of the polygon approach π.
Quantum algorithmic integrability: The metaphor of classical polygonal billiards
Mantica, Giorgio
2000-06-01
We study the algorithmic complexity of motions in classical polygonal billiards, which, as the number of sides increases, tend to curved billiards, both regular and chaotic. This study unveils the equivalence of this problem to the procedure of quantization: the average complexity of symbolic trajectories in polygonal billiards features the same scaling relations (with respect to the number of sides) that govern quantum systems when a semiclassical parameter is varied. Two cases, the polygonal approximations of the circle and of the stadium, are examined in detail and are presented as paradigms of quantization of integrable and chaotic systems.
Conformal array design on arbitrary polygon surface with transformation optics
Deng, Li; Wu, Yongle; Hong, Weijun; Zhu, Jianfeng; Peng, Biao; Li, Shufang
2016-06-01
A transformation-optics based method to design a conformal antenna array on an arbitrary polygon surface is proposed and demonstrated in this paper. This conformal antenna array can be adjusted to behave equivalently as a uniformly spaced linear array by applying an appropriate transformation medium. An typical example of general arbitrary polygon conformal arrays, not limited to circular array, is presented, verifying the proposed approach. In summary, the novel arbitrary polygon surface conformal array can be utilized in array synthesis and beam-forming, maintaining all benefits of linear array.
Alabama ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for dolphins and manatees in Alabama. Vector polygons in this data set represent marine mammal distribution...
Alabama ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for Alabama and Perdido Key beach mice in Alabama. Vector polygons in this data set represent the rare...
Bristol Bay, Alaska Subarea ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Guam and the Northern Mariana Islands ESI: HABITATS (Habitat Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for benthic marine habitats and plants in Guam and the Northern Mariana Islands. Vector polygons in this...
Southeast Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for brown bears in Southeast Alaska. Vector polygons in this data set represent locations of bear concentrations....
Spectral segmentation of polygonized images with normalized cuts
Energy Technology Data Exchange (ETDEWEB)
Matsekh, Anna [Los Alamos National Laboratory; Skurikhin, Alexei [Los Alamos National Laboratory; Rosten, Edward [UNIV OF CAMBRIDGE
2009-01-01
We analyze numerical behavior of the eigenvectors corresponding to the lowest eigenvalues of the generalized graph Laplacians arising in the Normalized Cuts formulations of the image segmentation problem on coarse polygonal grids.
Coastal Resources Atlas: Long Island: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles, estuarine turtles, and amphibians for Long Island, New York. Vector polygons in this data...
An equal area conversion model for rasterization of vector polygons
Institute of Scientific and Technical Information of China (English)
ZHOU ChengHu; OU Yang; YANG Liao; QIN Biao
2007-01-01
Vector-raster conversion is one of the classic research topics in the field of Geographical Information Systems (GIS). The algorithms commonly used in GIS are devoted to maintaining the vector polygons' shape characteristics, but neglect the gain and loss of a polygon's area, which is another important attribute. This paper proposes an equal-area conversion model based on an area compensation optimization principle. According to the topological relationship among polygons and boundary grids, a neighborhood compensation principle was adopted to assign the attributes of boundary grids and a global optimization algorithm was developed to minimize area distortion in the whole data set. Two experiments were designed and the results indicated that this algorithm not only guaranteed the area error is as small as possible, but also has the advantage as being adaptive to polygon shape and spatial structure.
Coastal Resources Atlas: Long Island: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species for Long Island, New York. Vector polygons...
Contour polygonal approximation using shortest path in networks
Backes, André Ricardo; Bruno, Odemir Martinez
2013-01-01
Contour polygonal approximation is a simplified representation of a contour by line segments, so that the main characteristics of the contour remain in a small number of line segments. This paper presents a novel method for polygonal approximation based on the Complex Networks theory. We convert each point of the contour into a vertex, so that we model a regular network. Then we transform this network into a Small-World Complex Network by applying some transformations over its edges. By analyzing of network properties, especially the geodesic path, we compute the polygonal approximation. The paper presents the main characteristics of the method, as well as its functionality. We evaluate the proposed method using benchmark contours, and compare its results with other polygonal approximation methods.
American Samoa ESI: BENTHIC (Benthic Marine Habitat Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for benthic habitats in American Samoa. Vector polygons in this data set represent the distribution of...
North Slope, Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for brown bears, caribou, and muskoxen for the North Slope, Alaska. Vector polygons in this data set...
Louisiana ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for terrestrial mammals in Louisiana. Vector polygons in this data set represent terrestrial mammal...
Maryland ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seals, whales, porpoise, and dolphin in Maryland. Vector polygons in this data set represent marine...
Western Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for brown bears in Western Alaska. Vector polygons in this data set represent terrestrial mammal...
Southeast Alaska ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for seals, porpoises, otters, and whales in coastal Southeast Alaska. Vector polygons in this data set represent...
Columbia River ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for Steller sea lions, harbor seals, and California sea lions in Columbia River. Vector polygons in this...
Guam and the Northern Mariana Islands ESI: REPTILES (Reptile Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles in Guam and the Northern Mariana Islands. Vector polygons in this data set represent turtle...
Louisiana ESI: LG_INDEX (Large Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
Maryland ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for river otters in Maryland. Vector polygons in this data set represent the terrestrial mammal...
Coastal Resources Atlas: Long Island: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for coastal, estuarine, and marine invertebrate species for Long Island, New York. Vector polygons in this...
Two-Dimensional (2D) Polygonal Electromagnetic Cloaks
Institute of Scientific and Technical Information of China (English)
LI Chao; YAO Kan; LI Fang
2009-01-01
Transformation optics offers remarkable control over electromagnetic fields and opens an exciting gateway to design 'invisible cloak devices' recently.We present an important class of two-dimensional (2D) cloaks with polygon geometries.Explicit expressions of transformed medium parameters are derived with their unique properties investigated.It is found that the elements of diagonalized permittivity tensors are always positive within an irregular polygon cloak besides one element diverges to plus infinity and the other two become zero at the inner boundary.At most positions,the principle axes of permittivity tensors do not align with position vectors.An irregular polygon cloak is designed and its invisibility to external electromagnetic waves is numerically verified.Since polygon cloaks can be tailored to resemble any objects,the transformation is finally generalized to the realization of 2D cloaks with arbitrary geometries.
Alabama ESI: ESI (Shoreline Types - Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing the shoreline and coastal habitats for Alabama, classified according to the Environmental Sensitivity...
Guam and the Northern Mariana Islands ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
American Samoa ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for American...
Western Alaska ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seals, whales, dolphins, walruses, and Steller sea lions in Western Alaska. Vector polygons in this...
Memorials (Polygons) at Little Bighorn Battlefield National Monument, Montana
National Park Service, Department of the Interior — This is a vector polygon file showing the memorials at Little Bighorn Battlefield National Monument (LIBI). The coordinates for this dataset were collected using a...
Columbia River ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Columbia...
BSYCHAB -- Habitat polygons for the Big Sycamore reserve area
U.S. Geological Survey, Department of the Interior — Benthic habitat polygon coverages have been created for marine reserve locations surrounding the Santa Barbara Basin. Diver, ROV and submersible video transects,...
Columbia River ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for western pond turtles and western painted turtles in Columbia River. Vector polygons in this data set...
Forests and Forest Cover - Ozark National Forest Service Compartments (polygon)
NSGIC GIS Inventory (aka Ramona) — Ozark - St. Francis National Forests stand inventory data for vegetation, maintained in polygon format. Compartment is defined as a division of forest for purposes...
Virginia ESI: T_MAMMAL (Terrestrial Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for the northern river otter in Virginia. Vector polygons in this data set represent terrestrial mammal...
Louisiana ESI: SM_INDEX (Small Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of all the hardcopy cartographic products produced as part of the Environmental Sensitivity Index...
VT Biodiversity Project - Representative Landscapes in Vermont polygons
Vermont Center for Geographic Information — (Link to Metadata) This coverage represents the results of an analysis of landscape diversity in Vermont. Polygons in the dataset represent as much as possible (in a...
Bristol Bay, Alaska Subarea ESI: BIOINDEX (Biological Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries of the 1:250,000 map boundaries used in the creation of the Environmental Sensitivity Index (ESI)...
PNW River Reach Files -- 1:100k Waterbodies (polygons)
Pacific States Marine Fisheries Commission — This feature class includes the POLYGON waterbody features from the 2001 version of the PNW River Reach files Arc/INFO coverage. Separate, companion feature classes...
Guam and the Northern Mariana Islands ESI: WETLANDS (Wetland Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the coastal wetland habitats for Guam and the Northern Mariana Islands classified according to the Environmental...
Coastal Resources Atlas: Long Island: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Long Island,...
American Samoa ESI: REPTILES (Reptile and Amphibian Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for sea turtles in American Samoa. Vector polygons in this data set represent sea turtle nesting and...
Region 9 NPL Sites (Superfund Sites 2013) Polygons
U.S. Environmental Protection Agency — NPL site POLYGON locations for the US EPA Region 9. NPL (National Priorities List) sites are hazardous waste sites that are eligible for extensive long-term cleanup...
North Slope, Alaska ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for whales, seals, walruses, and polar bears for the North Slope of Alaska. Vector polygons in this data...
Polygonal Homographic Orbits of the Curved n-Body Problem
Diacu, Florin
2010-01-01
In the 2-dimensional n-body problem in spaces of constant curvature, k nonzero, with n \\geq 3, we study polygonal homographic solutions. We first provide necessary and sufficient conditions for the existence of polygonal homographic orbits and then consider the case of regular polygons. We further use this criterion to show that, for any n \\geq 3, the regular n-gon is a polygonal homographic orbit if and only if all masses are equal. Then we prove the existence of relative equilib- ria of non-equal masses on the sphere of curvature k > 0 for n = 3 in the case of scalene triangles. Such triangular relative equilibria occur only along fixed geodesics and are generated from fixed points of the sphere. Finally, through a classification of the isosceles case, we prove that not any three masses can form a triangular relative equilibrium.
Virginia ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for dolphin, seals, whales, and porpoise in Virginia. Vector polygons in this data set represent marine...
American Samoa ESI: M_MAMMAL (Marine Mammal Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for whales and dolphins in American Samoa. Vector polygons in this data set represent marine mammal...
North Slope, Alaska ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for the North...
Bristol Bay, Alaska Subarea ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for the Bristol...
Southeast Alaska ESI: HABITATS (Habitat and Plant Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for seagrass habitats in Southeast Alaska. Vector polygons in this data set represent locations of seagrass...
Cook Inlet and Kenai Peninsula, Alaska ESI: FISH (Fish Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for herring spawning areas in Cook Inlet and Kenai Peninsula, Alaska. Vector polygons in this data set represent...
Cook Inlet and Kenai Peninsula, Alaska ESI: INDEX (Index Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the boundaries used in the creation of the Environmental Sensitivity Index (ESI) for Cook Inlet and Kenai...
Cook Inlet and Kenai Peninsula, Alaska ESI: INVERT (Invertebrate Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains biological resource data for razor clams in Cook Inlet and Kenai Peninsula, Alaska. Vector polygons in this data set represent locations of...
Southeast Alaska ESI: HYDRO (Hydrography Lines and Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector lines and polygons representing coastal hydrography used in the creation of the Environmental Sensitivity Index (ESI) for Southeast...
Columbia River ESI: NWI (National Wetlands Inventory - Polygons)
National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the wetlands of Columbia River classified according to the Environmental Sensitivity Index (ESI) classification...
Driving performance impairments due to hypovigilance on monotonous roads.
Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N
2011-11-01
Drivers' ability to react to unpredictable events deteriorates when exposed to highly predictable and uneventful driving tasks. Highway design reduces the driving task mainly to a lane-keeping manoeuvre. Such a task is monotonous, providing little stimulation and this contributes to crashes due to inattention. Research has shown that driver's hypovigilance can be assessed with EEG measurements and that driving performance is impaired during prolonged monotonous driving tasks. This paper aims to show that two dimensions of monotony - namely road design and road side variability - decrease vigilance and impair driving performance. This is the first study correlating hypovigilance and driver performance in varied monotonous conditions, particularly on a short time scale (a few seconds). We induced vigilance decrement as assessed with an EEG during a monotonous driving simulator experiment. Road monotony was varied through both road design and road side variability. The driver's decrease in vigilance occurred due to both road design and road scenery monotony and almost independently of the driver's sensation seeking level. Such impairment was also correlated to observable measurements from the driver, the car and the environment. During periods of hypovigilance, the driving performance impairment affected lane positioning, time to lane crossing, blink frequency, heart rate variability and non-specific electrodermal response rates. This work lays the foundation for the development of an in-vehicle device preventing hypovigilance crashes on monotonous roads.
Generalizing Lifted Tensor-Product Wavelets to Irregular Polygonal Domains
Energy Technology Data Exchange (ETDEWEB)
Bertram, M.; Duchaineau, M.A.; Hamann, B.; Joy, K.I.
2002-04-11
We present a new construction approach for symmetric lifted B-spline wavelets on irregular polygonal control meshes defining two-manifold topologies. Polygonal control meshes are recursively refined by stationary subdivision rules and converge to piecewise polynomial limit surfaces. At every subdivision level, our wavelet transforms provide an efficient way to add geometric details that are expanded from wavelet coefficients. Both wavelet decomposition and reconstruction operations are based on local lifting steps and have linear-time complexity.
Realistic roofs over a rectilinear polygon
Ahn, Heekap
2013-11-01
Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. According to this definition, some roofs may have faces isolated from the boundary of P or even local minima, which are undesirable for several practical reasons. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs and show that the straight skeleton induces a realistic roof with maximum height and volume. We also show that the maximum possible number of distinct realistic roofs over P is ((n-4)(n-4)/4 /2⌋) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n4) preprocessing time. We also present an O(n5)-time algorithm for computing a realistic roof with minimum height or volume. © 2013 Elsevier B.V.
Bifurcation of self-folded polygonal bilayers
Abdullah, Arif M.; Braun, Paul V.; Hsia, K. Jimmy
2017-09-01
Motivated by the self-assembly of natural systems, researchers have investigated the stimulus-responsive curving of thin-shell structures, which is also known as self-folding. Self-folding strategies not only offer possibilities to realize complicated shapes but also promise actuation at small length scales. Biaxial mismatch strain driven self-folding bilayers demonstrate bifurcation of equilibrium shapes (from quasi-axisymmetric doubly curved to approximately singly curved) during their stimulus-responsive morphing behavior. Being a structurally instable, bifurcation could be used to tune the self-folding behavior, and hence, a detailed understanding of this phenomenon is appealing from both fundamental and practical perspectives. In this work, we investigated the bifurcation behavior of self-folding bilayer polygons. For the mechanistic understanding, we developed finite element models of planar bilayers (consisting of a stimulus-responsive and a passive layer of material) that transform into 3D curved configurations. Our experiments with cross-linked Polydimethylsiloxane samples that change shapes in organic solvents confirmed our model predictions. Finally, we explored a design scheme to generate gripper-like architectures by avoiding the bifurcation of stimulus-responsive bilayers. Our research contributes to the broad field of self-assembly as the findings could motivate functional devices across multiple disciplines such as robotics, artificial muscles, therapeutic cargos, and reconfigurable biomedical devices.
Image segmentation by hierarchial agglomeration of polygons using ecological statistics
Prasad, Lakshman; Swaminarayan, Sriram
2013-04-23
A method for rapid hierarchical image segmentation based on perceptually driven contour completion and scene statistics is disclosed. The method begins with an initial fine-scale segmentation of an image, such as obtained by perceptual completion of partial contours into polygonal regions using region-contour correspondences established by Delaunay triangulation of edge pixels as implemented in VISTA. The resulting polygons are analyzed with respect to their size and color/intensity distributions and the structural properties of their boundaries. Statistical estimates of granularity of size, similarity of color, texture, and saliency of intervening boundaries are computed and formulated into logical (Boolean) predicates. The combined satisfiability of these Boolean predicates by a pair of adjacent polygons at a given segmentation level qualifies them for merging into a larger polygon representing a coarser, larger-scale feature of the pixel image and collectively obtains the next level of polygonal segments in a hierarchy of fine-to-coarse segmentations. The iterative application of this process precipitates textured regions as polygons with highly convolved boundaries and helps distinguish them from objects which typically have more regular boundaries. The method yields a multiscale decomposition of an image into constituent features that enjoy a hierarchical relationship with features at finer and coarser scales. This provides a traversable graph structure from which feature content and context in terms of other features can be derived, aiding in automated image understanding tasks. The method disclosed is highly efficient and can be used to decompose and analyze large images.
Intersectionality in European Union policymaking
DEFF Research Database (Denmark)
Lombardo, Emanuela; Agustin, Lise Rolandsen
2016-01-01
is particularly apt to deal with equality and diversity in policymaking. By analysing a selection of European Union policy documents on gender-based violence in the period 2000–2014, we attend to the question of what intersectionality can bring to policymaking in terms of strengthening inclusiveness and address...
Estimating monotonic rates from biological data using local linear regression.
Olito, Colin; White, Craig R; Marshall, Dustin J; Barneche, Diego R
2017-03-01
Accessing many fundamental questions in biology begins with empirical estimation of simple monotonic rates of underlying biological processes. Across a variety of disciplines, ranging from physiology to biogeochemistry, these rates are routinely estimated from non-linear and noisy time series data using linear regression and ad hoc manual truncation of non-linearities. Here, we introduce the R package LoLinR, a flexible toolkit to implement local linear regression techniques to objectively and reproducibly estimate monotonic biological rates from non-linear time series data, and demonstrate possible applications using metabolic rate data. LoLinR provides methods to easily and reliably estimate monotonic rates from time series data in a way that is statistically robust, facilitates reproducible research and is applicable to a wide variety of research disciplines in the biological sciences. © 2017. Published by The Company of Biologists Ltd.
Monotone traveling wavefronts of the KPP-Fisher delayed equation
Gomez, Adrian
2010-01-01
In the early 2000's, Gourley (2000), Wu et al. (2001), Ashwin et al. (2002) initiated the study of the positive wavefronts in the delayed Kolmogorov-Petrovskii-Piskunov-Fisher equation. Since then, this model has become one of the most popular objects in the studies of traveling waves for the monostable delayed reaction-diffusion equations. In this paper, we give a complete solution to the problem of existence and uniqueness of monotone waves in the KPP-Fisher equation. We show that each monotone traveling wave can be found via an iteration procedure. The proposed approach is based on the use of special monotone integral operators (which are different from the usual Wu-Zou operator) and appropriate upper and lower solutions associated to them. The analysis of the asymptotic expansions of the eventual traveling fronts at infinity is another key ingredient of our approach.
Efficient algorithm for Boolean operations on polygons%高效的多边形布尔计算方法
Institute of Scientific and Technical Information of China (English)
齐东洲; 吴敏
2014-01-01
In this paper, a new algorithm was proposed for Boolean operations on general polygons, including union, intersection and difference calculations of two polygons, which are of wide application in computer graphics. Our algorithm includes three main steps: computing the intersection points, inserting the intersection points into the polygon vertex lists, and vertex traversal. The adoption of single-linked list data structure enables less storage space. And through uniform processing on intersection points and beforehand collision detection to avoid complicated intersection calculation, this algorithm can accelerate the execution speed and reduce further the storage space. The algorithm possesses good robustness since it can tackle with many singular cases very well. Compared with the classical Weiler algorithm, Vatti algorithm and Greiner-Hormann algorithm, our algorithm has lower time complexity(O((m+n+k)log d))and space complexity. The experiments illustrate the efficiency of this algorithm. For a case with 2 222 × 2 222 vertices and 42 intersection points, this algorithm is 296 faster than Weiler algorithm. The main idea of this algorithm is also applicable to the union, intersection and difference calculation of polyhedra.%针对计算机图形学中应用广泛的多边形布尔计算，提出了一种新的、适用于一般多边形的并集、交集和差集算法。算法主要分为计算交点、将交点插入多边形顶点序列、遍历三个步骤。通过采用循环单链表的数据结构、避开复杂的出入点计算、及预先的一些碰撞检测以避开复杂的求交运算与链表遍历等技巧，提高了算法的执行速度、减少了存储单元。算法能够很好地处理一些奇异情形（边界情形），比如重叠边、交点为边的顶点等情形，具有很好的鲁棒性。与经典的Weiler算法、Vatti算法和Greiner-Hormann算法相比，该算法具有较低的时间复杂度O（（ m+n+k） log d））和
Monotone data visualization using rational trigonometric spline interpolation.
Ibraheem, Farheen; Hussain, Maria; Hussain, Malik Zawwar
2014-01-01
Rational cubic and bicubic trigonometric schemes are developed to conserve monotonicity of curve and surface data, respectively. The rational cubic function has four parameters in each subinterval, while the rational bicubic partially blended function has eight parameters in each rectangular patch. The monotonicity of curve and surface data is retained by developing constraints on some of these parameters in description of rational cubic and bicubic trigonometric functions. The remaining parameters are kept free to modify the shape of curve and surface if required. The developed algorithm is verified mathematically and demonstrated graphically.
Monotone Data Visualization Using Rational Trigonometric Spline Interpolation
Directory of Open Access Journals (Sweden)
Farheen Ibraheem
2014-01-01
Full Text Available Rational cubic and bicubic trigonometric schemes are developed to conserve monotonicity of curve and surface data, respectively. The rational cubic function has four parameters in each subinterval, while the rational bicubic partially blended function has eight parameters in each rectangular patch. The monotonicity of curve and surface data is retained by developing constraints on some of these parameters in description of rational cubic and bicubic trigonometric functions. The remaining parameters are kept free to modify the shape of curve and surface if required. The developed algorithm is verified mathematically and demonstrated graphically.
Ultimate generalization to monotonicity for uniform convergence of trigonometric series
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Chaundy and Jolliffe proved that if {a n } is a non-increasing (monotonic) real sequence with lim n →∞ a n = 0, then a necessary and sufficient condition for the uniform convergence of the series ∑∞ n=1 a n sin nx is lim n →∞ na n = 0. We generalize (or weaken) the monotonic condition on the coefficient sequence {a n } in this classical result to the so-called mean value bounded variation condition and prove that the generalized condition cannot be weakened further. We also establish an analogue to the generalized Chaundy-Jolliffe theorem in the complex space.
Vector optimization and monotone operators via convex duality recent advances
Grad, Sorin-Mihai
2014-01-01
This book investigates several duality approaches for vector optimization problems, while also comparing them. Special attention is paid to duality for linear vector optimization problems, for which a vector dual that avoids the shortcomings of the classical ones is proposed. Moreover, the book addresses different efficiency concepts for vector optimization problems. Among the problems that appear when the framework is generalized by considering set-valued functions, an increasing interest is generated by those involving monotone operators, especially now that new methods for approaching them by means of convex analysis have been developed. Following this path, the book provides several results on different properties of sums of monotone operators.
Reconstructing surface triangulations by their intersection matrices
2014-01-01
The intersection matrix of a finite simplicial complex has as each of its entries the rank of the intersection of its respective simplices. We prove that such matrix defines the triangulation of a closed connected surface up to isomorphism.
Using Intersectionality in Student Affairs Research
Strayhorn, Terrell L.
2017-01-01
This chapter presents intersectionality as a useful heuristic for conducting research in higher education and student affairs contexts. Much more than just another theory, intersectionality can powerfully shape student affairs research in both obvious and tacit ways.
The Clique Problem in Ray Intersection Graphs
Cabello, Sergio; Langerman, Stefan
2011-01-01
Ray intersection graphs are intersection graphs of rays, or halflines, in the plane. We show that any planar graph has an even subdivision whose complement is a ray intersection graph. The construction can be done in polynomial time and implies that finding a maximum clique in a segment intersection graph is NP-hard. This solves a 21-year old open problem posed by Kratochv\\'il and Ne\\v{s}et\\v{r}il.
The reference phantoms: voxel vs polygon.
Kim, C H; Yeom, Y S; Nguyen, T T; Wang, Z J; Kim, H S; Han, M C; Lee, J K; Zankl, M; Petoussi-Henss, N; Bolch, W E; Lee, C; Chung, B S
2016-06-01
The International Commission on Radiological Protection (ICRP) reference male and female adult phantoms, described in Publication 110, are voxel phantoms based on whole-body computed tomography scans of a male and a female patient, respectively. The voxel in-plane resolution and the slice thickness, of the order of a few millimetres, are insufficient for proper segmentation of smaller tissues such as the lens of the eye, the skin, and the walls of some organs. The calculated doses for these tissues therefore present some limitations, particularly for weakly penetrating radiation. Similarly, the Publication 110 phantoms cannot represent 8-40-µm-thick target regions in respiratory or alimentary tract organs. Separate stylised models have been used to represent these tissues for calculation of the ICRP reference dose coefficients (DCs). ICRP Committee 2 recently initiated a research project, the ultimate goal of which is to convert the Publication 110 phantoms to a high-quality polygon-mesh (PM) format, including all source and target regions, even those of the 8-40-µm-thick alimentary and respiratory tract organs. It is expected that the converted phantoms would lead to the same or very similar DCs as the Publication 110 reference phantoms for penetrating radiation and, at the same time, provide more accurate DCs for weakly penetrating radiation and small tissues. Additionally, the reference phantoms in the PM format would be easily deformable and, as such, could serve as a starting point to create phantoms of various postures for use, for example, in accidental dose calculations. This paper will discuss the current progress of the phantom conversion project and its significance for ICRP DC calculations.
Mediavilla, E.; Mediavilla, T.; Muñoz, J. A.; Ariza, O.; Lopez, P.; Gonzalez-Morcillo, C.; Jimenez-Vicente, J.
2011-11-01
We derive an exact solution (in the form of a series expansion) to compute gravitational lensing magnification maps. It is based on the backward gravitational lens mapping of a partition of the image plane in polygonal cells (inverse polygon mapping, IPM), not including critical points (except perhaps at the cell boundaries). The zeroth-order term of the series expansion leads to the method described by Mediavilla et al. The first-order term is used to study the error induced by the truncation of the series at zeroth order, explaining the high accuracy of the IPM even at this low order of approximation. Interpreting the Inverse Ray Shooting (IRS) method in terms of IPM, we explain the previously reported N -3/4 dependence of the IRS error with the number of collected rays per pixel. Cells intersected by critical curves (critical cells) transform to non-simply connected regions with topological pathologies like auto-overlapping or non-preservation of the boundary under the transformation. To define a non-critical partition, we use a linear approximation of the critical curve to divide each critical cell into two non-critical subcells. The optimal choice of the cell size depends basically on the curvature of the critical curves. For typical applications in which the pixel of the magnification map is a small fraction of the Einstein radius, a one-to-one relationship between the cell and pixel sizes in the absence of lensing guarantees both the consistence of the method and a very high accuracy. This prescription is simple but very conservative. We show that substantially larger cells can be used to obtain magnification maps with huge savings in computation time.
MONOTONE ITERATION FOR ELLIPTIC PDEs WITH DISCONTINUOUS NONLINEAR TERMS
Institute of Scientific and Technical Information of China (English)
Zou Qingsong
2005-01-01
In this paper, we use monotone iterative techniques to show the existence of maximal or minimal solutions of some elliptic PDEs with nonlinear discontinuous terms. As the numerical analysis of this PDEs is concerned, we prove the convergence of discrete extremal solutions.
Modeling non-monotone risk aversion using SAHARA utility functions
A. Chen; A. Pelsser; M. Vellekoop
2011-01-01
We develop a new class of utility functions, SAHARA utility, with the distinguishing feature that it allows absolute risk aversion to be non-monotone and implements the assumption that agents may become less risk averse for very low values of wealth. The class contains the well-known exponential and
On Uniqueness of Conjugacy of Continuous and Piecewise Monotone Functions
Directory of Open Access Journals (Sweden)
Ciepliński Krzysztof
2009-01-01
Full Text Available We investigate the existence and uniqueness of solutions of the functional equation , , where are closed intervals, and , are some continuous piecewise monotone functions. A fixed point principle plays a crucial role in the proof of our main result.
L^p solutions of reflected BSDEs under monotonicity condition
Rozkosz, Andrzej
2012-01-01
We prove existence and uniqueness of L^p solutions of reflected backward stochastic differential equations with p-integrable data and generators satisfying the monotonicity condition. We also show that the solution may be approximated by the penalization method. Our results are new even in the classical case p=2.
A monotonic method for solving nonlinear optimal control problems
Salomon, Julien
2009-01-01
Initially introduced in the framework of quantum control, the so-called monotonic algorithms have shown excellent numerical results when dealing with various bilinear optimal control problems. This paper aims at presenting a unified formulation of such procedures and the intrinsic assumptions they require. In this framework, we prove the feasibility of the general algorithm. Finally, we explain how these assumptions can be relaxed.
On Some Conjectures on the Monotonicity of Some Arithmetical Sequences
2012-01-01
THE MONOTONICITY OF SOME ARITHMETICAL SEQUENCES ∗ Florian Luca † Centro de Ciencias Matemáticas, Universidad Nacional Autonoma de México, C.P. 58089...visit of P. S. to the Centro de Ciencias Matemáticas de la UNAM in Morelia in August 2012. During the preparation of this paper, F. L. was supported in
Interval Routing and Minor-Monotone Graph Parameters
Bakker, E.M.; Bodlaender, H.L.; Tan, R.B.; Leeuwen, J. van
2006-01-01
We survey a number of minor-monotone graph parameters and their relationship to the complexity of routing on graphs. In particular we compare the interval routing parameters κslir(G) and κsir(G) with Colin de Verdi`ere’s graph invariant μ(G) and its variants λ(G) and κ(G). We show that for all the k
Multivariate Regression with Monotone Missing Observation of the Dependent Variables
Raats, V.M.; van der Genugten, B.B.; Moors, J.J.A.
2002-01-01
Multivariate regression is discussed, where the observations of the dependent variables are (monotone) missing completely at random; the explanatory variables are assumed to be completely observed.We discuss OLS-, GLS- and a certain form of E(stimated) GLS-estimation.It turns out that
Minimum Cost Spanning Tree Games and Population Monotonic Allocation Schemes
Norde, H.W.; Moretti, S.; Tijs, S.H.
2001-01-01
In this paper we present the Subtraction Algorithm that computes for every classical minimum cost spanning tree game a population monotonic allocation scheme.As a basis for this algorithm serves a decomposition theorem that shows that every minimum cost spanning tree game can be written as nonnegati
Size monotonicity and stability of the core in hedonic games
Dimitrov, Dinko; Sung, Shao Chin
2011-01-01
We show that the core of each strongly size monotonic hedonic game is not empty and is externally stable. This is in sharp contrast to other sufficient conditions for core non-emptiness which do not even guarantee the existence of a stable set in such games.
Monotone missing data and repeated controls of fallible authors
Raats, V.M.
2004-01-01
Chapters 2 and 3 focus on repeated audit controls with categorical variables. Chapter 4 and 5 introduce and analyse a very general multivariate regression model for (monotone) missing data. In the final Chapter 6 the previous chapters are combined into a more realistic model for repeated audit contr
A POTENTIAL REDUCTION ALGORITHM FOR MONOTONE VARIATIONAL INEQUALITY PROBLEMS
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A potential reduction algorithm is proposed for the solution of monotone variational inequality problems. At each step of the algorithm, a system of linear equations is solved to get the search direction and the Armijo's rule is used to determine the stepsize.It is proved that the algorithm is globally convergent. Computational results are reported.
Relaxing monotonicity in the identification of local average treatment effects
DEFF Research Database (Denmark)
Huber, Martin; Mellace, Giovanni
In heterogeneous treatment effect models with endogeneity, the identification of the local average treatment effect (LATE) typically relies on an instrument that satisfies two conditions: (i) joint independence of the potential post-instrument variables and the instrument and (ii) monotonicity...
Incorporating "Unconscious Reanalysis" into an Incremental, Monotonic Parser
Sturt, P
1995-01-01
This paper describes an implementation based on a recent model in the psycholinguistic literature. We define a parsing operation which allows the reanalysis of dependencies within an incremental and monotonic processing architecture, and discuss search strategies for its application in a head-initial language (English) and a head-final language (Japanese).
Interval Routing and Minor-Monotone Graph Parameters
Bakker, E.M.; Bodlaender, H.L.; Tan, R.B.; Leeuwen, J. van
2006-01-01
We survey a number of minor-monotone graph parameters and their relationship to the complexity of routing on graphs. In particular we compare the interval routing parameters κslir(G) and κsir(G) with Colin de Verdi`ere’s graph invariant μ(G) and its variants λ(G) and κ(G). We show that for all the
Reasoning Biases, Non-Monotonic Logics, and Belief Revision
Dutilh Novaes, Catarina; Veluwenkamp, Herman
2017-01-01
A range of formal models of human reasoning have been proposed in a number of fields such as philosophy, logic, artificial intelligence, computer science, psychology, cognitive science etc.: various logics (epistemic logics; non-monotonic logics), probabilistic systems (most notably, but not exclusi
Finding largest small polygons with GloptiPoly
Henrion, Didier
2011-01-01
A small polygon is a convex polygon of unit diameter. We are interested in small polygons which have the largest area for a given number of vertices $n$. Many instances are already solved in the literature, namely for all odd $n$, and for $n=4, 6$ and 8. Thus, for even $n\\geq 10$, instances of this problem remain open. Finding those largest small polygons can be formulated as nonconvex quadratic programming problems which can challenge state-of-the-art global optimization algorithms. We show that a recently developed technique for global polynomial optimization, based on a semidefinite programming approach to the generalized problem of moments and implemented in the public-domain Matlab package GloptiPoly, can successfully find largest small polygons for $n=10$ and $n=12$. Therefore this significantly improves existing results in the domain. When coupled with accurate convex conic solvers, GloptiPoly can provide numerical guarantees of global optimality, as well as rigorous guarantees relying on interval arit...
Composite fluxbranes with general intersections
Ivashchuk, V D
2002-01-01
Generalized composite fluxbrane solutions for a wide class of intersection rules are obtained. The solutions are defined on a manifold which contains a product of n Ricci-flat spaces M_1 x ... x M_n with 1-dimensional M_1. They are defined up to a set of functions H_s obeying non-linear differential equations equivalent to Toda-type equations with certain boundary conditions imposed. A conjecture on polynomial structure of governing functions H_s for intersections related to semisimple Lie algebras is suggested. This conjecture is valid for Lie algebras: A_m, C_{m+1}, m > 0. For simple Lie algebras the powers of polynomials coincide with the components of the dual Weyl vector in the basis of simple roots. Explicit formulas for A_1 + ... + A_1 (orthogonal), "block-ortogonal" and A_2 solutions are obtained. Certain examples of solutions in D = 11 and D =10 (II A) supergravities (e.g. with A_2 intersection rules) and Kaluza-Klein dyonic A_2 flux tube, are considered.
A QUALITY ASSESSMENT METHOD FOR 3D ROAD POLYGON OBJECTS
Directory of Open Access Journals (Sweden)
L. Gao
2015-08-01
Full Text Available With the development of the economy, the fast and accurate extraction of the city road is significant for GIS data collection and update, remote sensing images interpretation, mapping and spatial database updating etc. 3D GIS has attracted more and more attentions from academics, industries and governments with the increase of requirements for interoperability and integration of different sources of data. The quality of 3D geographic objects is very important for spatial analysis and decision-making. This paper presents a method for the quality assessment of the 3D road polygon objects which is created by integrating 2D Road Polygon data with LiDAR point cloud and other height information such as Spot Height data in Hong Kong Island. The quality of the created 3D road polygon data set is evaluated by the vertical accuracy, geometric and attribute accuracy, connectivity error, undulation error and completeness error and the final results are presented.
Vibration induced flow in hoppers: DEM 2D polygon model
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
A two-dimensional discrete element model (DEM) simulation of cohesive polygonal particles has been developed to assess the benefit of point source vibration to induce flow in wedge-shaped hoppers. The particle-particle interaction model used is based on a multi-contact principle.The first part of the study investigated particle discharge under gravity without vibration to determine the critical orifice size (Be) to just sustain flow as a function of particle shape. It is shown that polygonal-shaped particles need a larger orifice than circular particles. It is also shown that Be decreases as the number of particle vertices increases. Addition of circular particles promotes flow of polygons in a linear manner.The second part of the study showed that vibration could enhance flow, effectively reducing Be. The model demonstrated the importance of vibrator location (height), consistent with previous continuum model results, and vibration amplitude in enhancing flow.
Preparation Of Control Space For Remeshing Of Polygonal Surfaces
Directory of Open Access Journals (Sweden)
Tomasz Jurczyk
2013-01-01
Full Text Available The subject of the article concerns the issues of remeshing, transforming a polygonal mesh into a triangular mesh adapted to surface. From the initial polygonal mesh the curvature of surface and boundary is retrieved and used to calculate a metric tensor varying in three-dimensional space. In the proposed approach the curvature is computed using local approximation of surfaces and curves on the basis of vertices of the polygonal mesh. An essential part of the presented remeshing procedure is creation of a control space structure based on the retrieved discrete data. The subsequent process of remeshing is then supervised by the contents of this auxiliary structure. The article presents various aspects related to the procedure of initialization, creation and adjusting the control space structure.
Measured Two-Dimensional Ice-Wedge Polygon Thermal Dynamics
Cable, William; Romanovsky, Vladimir; Busey, Robert
2016-04-01
Ice-wedge polygons are perhaps the most dominant permafrost related features in the arctic landscape. The microtopography of these features, that includes rims, troughs, and high and low polygon centers, alters the local hydrology, as water tends to collect in the low areas. During winter, wind redistribution of snow leads to an increased snowpack depth in the low areas, while the slightly higher areas often have very thin snow cover, leading to differences across the landscape in vegetation communities and soil moisture between higher and lower areas. These differences in local surface conditions lead to spatial variability of the ground thermal regime in the different microtopographic areas and between different types of ice-wedge polygons. To study these features in depth, we established temperature transects across four different types of ice-wedge polygons near Barrow, Alaska. The transects were composed of five vertical array thermistor probes (VATP) beginning in the center of each polygon and extending through the trough to the rim of the adjacent polygon. Each VATP had 16 thermistors from the surface to a depth of 1.5 m. In addition to these 80 subsurface temperature measurement points per polygon, soil moisture, thermal conductivity, heat flux, and snow depth were all measured in multiple locations for each polygon. Above ground, a full suite of micrometeorological instrumentation was present at each polygon. Data from these sites has been collected continuously for the last three years. We found snow cover, timing and depth, and active layer soil moisture to be major controlling factors in the observed thermal regimes. In troughs and in the centers of low-center polygons, the combined effect of typically saturated soils and increased snow accumulation resulted in the highest mean annual ground temperatures (MAGT). Additionally, these areas were the last part of the polygon to refreeze during the winter. However, increased active layer thickness was not
The finite cell method for polygonal meshes: poly-FCM
Duczek, Sascha; Gabbert, Ulrich
2016-10-01
In the current article, we extend the two-dimensional version of the finite cell method (FCM), which has so far only been used for structured quadrilateral meshes, to unstructured polygonal discretizations. Therefore, the adaptive quadtree-based numerical integration technique is reformulated and the notion of generalized barycentric coordinates is introduced. We show that the resulting polygonal (poly-)FCM approach retains the optimal rates of convergence if and only if the geometry of the structure is adequately resolved. The main advantage of the proposed method is that it inherits the ability of polygonal finite elements for local mesh refinement and for the construction of transition elements (e.g. conforming quadtree meshes without hanging nodes). These properties along with the performance of the poly-FCM are illustrated by means of several benchmark problems for both static and dynamic cases.
Non-monotonic effect of confinement on the glass transition
Varnik, Fathollah; Franosch, Thomas
2016-04-01
The relaxation dynamics of glass forming liquids and their structure are influenced in the vicinity of confining walls. This effect has mostly been observed to be a monotonic function of the slit width. Recently, a qualitatively new behaviour has been uncovered by Mittal and coworkers, who reported that the single particle dynamics in a hard-sphere fluid confined in a planar slit varies in a non-monotonic way as the slit width is decreased from five to roughly two particle diametres (Mittal et al 2008 Phys. Rev. Lett. 100 145901). In view of the great potential of this effect for applications in those fields of science and industry, where liquids occur under strong confinement (e.g. nano-technology), the number of researchers studying various aspects and consequences of this non-monotonic behaviour has been rapidly growing. This review aims at providing an overview of the research activity in this newly emerging field. We first briefly discuss how competing mechanisms such as packing effects and short-range attraction may lead to a non-monotonic glass transition scenario in the bulk. We then analyse confinement effects on the dynamics of fluids using a thermodynamic route which relates the single particle dynamics to the excess entropy. Moreover, relating the diffusive dynamics to the Widom’s insertion probability, the oscillations of the local dynamics with density at moderate densities are fairly well described. At high densities belonging to the supercooled regime, however, this approach breaks down signaling the onset of strongly collective effects. Indeed, confinement introduces a new length scale which in the limit of high densities and small pore sizes competes with the short-range local order of the fluid. This gives rise to a non-monotonic dependence of the packing structure on confinement, with a corresponding effect on the dynamics of structural relaxation. This non-monotonic effect occurs also in the case of a cone-plate type channel, where the degree
Polygonal Approximation Using an Artificial Bee Colony Algorithm
Directory of Open Access Journals (Sweden)
Shu-Chien Huang
2015-01-01
Full Text Available A polygonal approximation method based on the new artificial bee colony (NABC algorithm is proposed in this paper. In the present method, a solution is represented by a vector, and the objective function is defined as the integral square error between the given curve and its corresponding polygon. The search process, including the employed bee stage, the onlooker bee stage, and the scout bee stage, has been constructed for this specific problem. Most experiments show that the present method when compared with the DE-based method can obtain superior approximation results with less error norm with respect to the original curves.
A Hybrid Approach to Proving Memory Reference Monotonicity
Oancea, Cosmin E.
2013-01-01
Array references indexed by non-linear expressions or subscript arrays represent a major obstacle to compiler analysis and to automatic parallelization. Most previous proposed solutions either enhance the static analysis repertoire to recognize more patterns, to infer array-value properties, and to refine the mathematical support, or apply expensive run time analysis of memory reference traces to disambiguate these accesses. This paper presents an automated solution based on static construction of access summaries, in which the reference non-linearity problem can be solved for a large number of reference patterns by extracting arbitrarily-shaped predicates that can (in)validate the reference monotonicity property and thus (dis)prove loop independence. Experiments on six benchmarks show that our general technique for dynamic validation of the monotonicity property can cover a large class of codes, incurs minimal run-time overhead and obtains good speedups. © 2013 Springer-Verlag.
Measurement of non-monotonic Casimir forces between silicon nanostructures
Tang, L.; Wang, M.; Ng, C. Y.; Nikolic, M.; Chan, C. T.; Rodriguez, A. W.; Chan, H. B.
2017-01-01
Casimir forces are of fundamental interest because they originate from quantum fluctuations of the electromagnetic field. Apart from controlling this force via the optical properties of materials, a number of novel geometries have been proposed to generate repulsive and/or non-monotonic Casimir forces between bodies separated by vacuum gaps. Experimental realization of these geometries, however, is hindered by the difficulties in alignment when the bodies are brought into close proximity. Here, using an on-chip platform with integrated force sensors and actuators, we circumvent the alignment problem and measure the Casimir force between two surfaces with nanoscale protrusions. We demonstrate that the force depends non-monotonically on the displacement. At some displacements, the Casimir force leads to an effective stiffening of the nanomechanical spring. Our findings pave the way for exploiting the Casimir force in nanomechanical systems using structures of complex and non-conventional shapes.
A Monotonic Precise Current DAC for Sensor Applications
Directory of Open Access Journals (Sweden)
P. Horsky
2008-12-01
Full Text Available In this paper a 17 bit monotonic precise current DAC for sensor applications is described. It is working in a harsh automotive environment in a wide temperature range with high output voltage swing and low current consumption. To guarantee monotonicity current division and segmentation techniques are used. To improve the output impedance, the accuracy and the voltage compliance of the DAC, two active cascoding loops and one follower loop are used. The resolution of the DAC is further increased by applying pulse width modulation to one fine LSB current. To achieve low power consumption unused coarse current sources are switched off. Several second order technological effects influencing final performance and circuits dealing with them are discussed.
Computation of Optimal Monotonicity Preserving General Linear Methods
Ketcheson, David I.
2009-07-01
Monotonicity preserving numerical methods for ordinary differential equations prevent the growth of propagated errors and preserve convex boundedness properties of the solution. We formulate the problem of finding optimal monotonicity preserving general linear methods for linear autonomous equations, and propose an efficient algorithm for its solution. This algorithm reliably finds optimal methods even among classes involving very high order accuracy and that use many steps and/or stages. The optimality of some recently proposed methods is verified, and many more efficient methods are found. We use similar algorithms to find optimal strong stability preserving linear multistep methods of both explicit and implicit type, including methods for hyperbolic PDEs that use downwind-biased operators.
Rational functions with maximal radius of absolute monotonicity
Loczi, Lajos
2014-05-19
We study the radius of absolute monotonicity R of rational functions with numerator and denominator of degree s that approximate the exponential function to order p. Such functions arise in the application of implicit s-stage, order p Runge-Kutta methods for initial value problems and the radius of absolute monotonicity governs the numerical preservation of properties like positivity and maximum-norm contractivity. We construct a function with p=2 and R>2s, disproving a conjecture of van de Griend and Kraaijevanger. We determine the maximum attainable radius for functions in several one-parameter families of rational functions. Moreover, we prove earlier conjectured optimal radii in some families with 2 or 3 parameters via uniqueness arguments for systems of polynomial inequalities. Our results also prove the optimality of some strong stability preserving implicit and singly diagonally implicit Runge-Kutta methods. Whereas previous results in this area were primarily numerical, we give all constants as exact algebraic numbers.
United States National Grid for New Mexico, UTM 13, (1000m X 1000m polygons )
Earth Data Analysis Center, University of New Mexico — This is a polygon feature data layer of United States National Grid (1000m x 1000m polygons ) constructed by the Center for Interdisciplinary Geospatial Information...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Petit Bois Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Cat Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Ship Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Horn Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Petit Bois Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 271 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Horn Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 254 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Cat Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 268 polygon shapefiles...
United States National Grid for New Mexico, UTM 12, (1000m X 1000m polygons )
Earth Data Analysis Center, University of New Mexico — This is a polygon feature data layer of United States National Grid (1000m x 1000m polygons ) constructed by the Center for Interdisciplinary Geospatial Information...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Petit Bois Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Dauphin Island, Alabama (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Petit Bois Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 271 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Horn Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 254 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Horn Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Ship Island, Mississippi (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Cat Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 268 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Dauphin Island, Alabama (Polygon: Individual Dates) is a dataset consisting of 223 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Dauphin Island, Alabama (Polygon: Individual Dates) is a dataset consisting of 223 polygon shapefiles...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Dauphin Island, Alabama (Polygon: Combined Dates) is a polygon shapefile representing shorelines generated from...
U.S. Geological Survey, Department of the Interior — Shorelines Extracted from 1984-2015 Landsat Imagery: Ship Island, Mississippi (Polygon: Individual Dates) is a dataset consisting of 280 polygon shapefiles...
Boolean Expressions of Rectilinear Polygons with VLSI Applications.
1982-11-01
Ottmann [6] in optimal time and space. Thus, we will use their technique to determine and report the intersection endpoints. The detection and report... Ottmann , "Algorithms for reporting and counting geometric intersections," IEEE Trans. Comput., vol. C-28, pp. 643-647, Sept. 1979. 7. W. J. Paul, R. E
On Uniqueness of Conjugacy of Continuous and Piecewise Monotone Functions
Directory of Open Access Journals (Sweden)
Krzysztof Ciepliński
2009-01-01
Full Text Available We investigate the existence and uniqueness of solutions φ:I→J of the functional equation φ(f(x=F(φ(x, x∈I, where I,J are closed intervals, and f:I→I, F:J→J are some continuous piecewise monotone functions. A fixed point principle plays a crucial role in the proof of our main result.
Block Monotone Iterative Algorithms for Variational Inequalities with Nonlinear Operators
Institute of Scientific and Technical Information of China (English)
Ming-hui Ren; Jin-ping Zeng
2008-01-01
Some block iterative methods for solving variational inequalities with nonlinear operators are proposed. Monotone convergence of the algorithms is obtained. Some comparison theorems are also established.Compared with the research work in given by Pao in 1995 for nonlinear equations and research work in given by Zeng and Zhou in 2002 for elliptic variational inequalities, the algorithms proposed in this paper are independent of the boundedness of the derivatives of the nonlinear operator.
Monotonic Property in Field Algebra of G-Spin Model
Institute of Scientific and Technical Information of China (English)
蒋立宁
2003-01-01
Let F be the field algebra of G-spin model, D(G) the double algebra of a finite group G and D(H) the sub-Hopf algerba of D(G) determined by the subgroup H of G. The paper builds a correspondence between D(H) and the D(H)-invariant sub-C*-algebra AH in F, and proves that the correspondence is strictly monotonic.
Modeling argumentation based semantics using non-monotonic reasoning
2005-01-01
Argumentation theory is an alternative style of formalizing non-monotonic reasoning. It seems, argumentation theory is a suitable framework for practical and uncertain reasoning, where arguments support conclusions. Dung's approach is an unifying framework which has played an influential role on argumentation research and Artificial Intelligence. Even though the success of the argumentation theory, it seems that argumentation theory is so far from being efficiently implemented like the logic ...
Nonparametric estimation for hazard rate monotonously decreasing system
Institute of Scientific and Technical Information of China (English)
Han Fengyan; Li Weisong
2005-01-01
Estimation of density and hazard rate is very important to the reliability analysis of a system. In order to estimate the density and hazard rate of a hazard rate monotonously decreasing system, a new nonparametric estimator is put forward. The estimator is based on the kernel function method and optimum algorithm. Numerical experiment shows that the method is accurate enough and can be used in many cases.
Stability and monotonicity of Lotka-Volterra type operators
Mukhamedov, Farrukh
2009-01-01
In the present paper, we study Lotka-Volterra (LV) type operators defined in finite dimensional simplex. We prove that any LV type operator is a surjection of the simplex. After, we introduce a new class of LV-type operators, called $M$LV type. We prove convergence of their trajectories and study certain its properties. Moreover, we show that such kind of operators have totaly different behavior than ${\\mathbf{f}}$-monotone LV type operators.
Projective modules and complete intersections
Mandal, Satya
1997-01-01
In these notes on "Projective Modules and Complete Intersections" an account on the recent developments in research on this subject is presented. The author's preference for the technique of Patching isotopic isomorphisms due to Quillen, formalized by Plumsted, over the techniques of elementary matrices is evident here. The treatment of Basic Element theory here incorporates Plumstead's idea of the "generalized dimension functions". These notes are highly selfcontained and should be accessible to any graduate student in commutative algebra or algebraic geometry. They include fully self-contained presentations of the theorems of Ferrand-Szpiro, Cowsik-Nori and the techniques of Lindel.
Monotone traveling wavefronts of the KPP-Fisher delayed equation
Gomez, Adrian; Trofimchuk, Sergei
In the early 2000's, Gourley (2000), Wu et al. (2001), Ashwin et al. (2002) initiated the study of the positive wavefronts in the delayed Kolmogorov-Petrovskii-Piskunov-Fisher equation u(t,x)=Δu(t,x)+u(t,x)(1-u(t-h,x)), u⩾0, x∈R. Since then, this model has become one of the most popular objects in the studies of traveling waves for the monostable delayed reaction-diffusion equations. In this paper, we give a complete solution to the problem of existence and uniqueness of monotone waves in Eq. (*). We show that each monotone traveling wave can be found via an iteration procedure. The proposed approach is based on the use of special monotone integral operators (which are different from the usual Wu-Zou operator) and appropriate upper and lower solutions associated to them. The analysis of the asymptotic expansions of the eventual traveling fronts at infinity is another key ingredient of our approach.
Solving the power flow equations: a monotone operator approach
Energy Technology Data Exchange (ETDEWEB)
Dvijotham, Krishnamurthy [California Inst. of Technology (CalTech), Pasadena, CA (United States); Low, Steven [California Inst. of Technology (CalTech), Pasadena, CA (United States); Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-07-21
The AC power flow equations underlie all operational aspects of power systems. They are solved routinely in operational practice using the Newton-Raphson method and its variants. These methods work well given a good initial “guess” for the solution, which is always available in normal system operations. However, with the increase in levels of intermittent generation, the assumption of a good initial guess always being available is no longer valid. In this paper, we solve this problem using the theory of monotone operators. We show that it is possible to compute (using an offline optimization) a “monotonicity domain” in the space of voltage phasors. Given this domain, there is a simple efficient algorithm that will either find a solution in the domain, or provably certify that no solutions exist in it. We validate the approach on several IEEE test cases and demonstrate that the offline optimization can be performed tractably and the computed “monotonicity domain” includes all practically relevant power flow solutions.
The Use of GIS Software to Deselect Forest Polygons by Their Location Relative to Linear Objects
Directory of Open Access Journals (Sweden)
S. K. Farber
2014-04-01
Full Text Available Polygon layers obtained on the basis of the DEM, may have specific characteristics, such as the emergence of geographically disparate polygons with the same identification number. The paper discusses the experience of spatial analysis such polygon layers, namely the experience of forest parcels adjacent to the parts of a hydrological network, using Arc Map 9.3.1. GIS software.
Tropical intersection theory on R^n
Flossmann, Simon
2014-01-01
In these notes we survey the tropical intersection theory on R^n by deriving the properties for tropical cycles from the corresponding properties in Chow cohomology. For this we review the stable intersection product introduced by Mikhalkin and the push forward of tropical cycles defined by Allermann and Rau. Furthermore we define a pull back for tropical cycles based on the pull back of Minkowski weights. This pull back commutes with the tropical intersection product and satisfies the projec...
Tropical intersection theory on R^n
Flossmann, Simon
2014-01-01
In these notes we survey the tropical intersection theory on R^n by deriving the properties for tropical cycles from the corresponding properties in Chow cohomology. For this we review the stable intersection product introduced by Mikhalkin and the push forward of tropical cycles defined by Allermann and Rau. Furthermore we define a pull back for tropical cycles based on the pull back of Minkowski weights. This pull back commutes with the tropical intersection product and satisfies the projec...
Institute of Scientific and Technical Information of China (English)
2008-01-01
In this paper the author first introduce a new concept of Lp-dual mixed volumes of star bodies which extends the classical dual mixed volumes. Moreover, we extend the notions of Lp- intersection body to Lp-mixed intersection body. Inequalities for Lp-dual mixed volumes of Lp-mixed intersection bodies are established and the results established here provide new estimates for these type of inequalities.
Pattern classification approaches to matching building polygons at multiple scales
Zhang, X; Zhao, X.; Molenaar, M.; Stoter, J.; Kraak M-J.; Ai, T.
2012-01-01
Matching of building polygons with different levels of detail is crucial in the maintenance and quality assessment of multi-representation databases. Two general problems need to be addressed in the matching process: (1) Which criteria are suitable? (2) How to effectively combine different criteria
Polygons, Pillars and Pavilions: Discovering Connections between Geometry and Architecture
Madden, Sean Patrick
2017-01-01
Crowning the second semester of geometry, taught within a Catholic middle school, the author's students explored connections between the geometry of regular polygons and architecture of local buildings. They went on to explore how these principles apply famous buildings around the world such as the monuments of Washington, D.C. and the elliptical…
Fat Polygonal Partitions with Applications to Visualization and Embeddings
de Berg, Mark; Sidiropoulos, Anastasios
2010-01-01
Let T be a rooted and weighted tree, where the weight of any node is equal to the sum of the weights of its children. The popular Treemap algorithm visualizes such a tree as a hierarchical partition of a square into rectangles, where the area of the rectangle corresponding to any node in T is equal to the weight of that node. The aspect ratio of the rectangles in such a rectangular partition necessarily depends on the weights and can become arbitrarily high. We introduce a new hierarchical partition scheme, called a polygonal partition, which uses convex polygons rather than just rectangles. We present two methods for constructing polygonal partitions, both having guarantees on the worst-case aspect ratio of the constructed polygons; in particular, both methods guarantee a bound on the aspect ratio that is independent of the weights of the nodes. We also consider rectangular partitions with slack, where the areas of the rectangles may differ slightly from the weights of the corresponding nodes. We show that t...
Micron-scale pattern formation in prestressed polygonal films
Annabattula, R. K.; Onck, P. R.
2011-01-01
In this paper we explore the spontaneous formation of micropatterns in thin prestressed polygonal films using finite element simulations. We study films with different size, thickness, and shape, including square, rectangular, pentagonal, and hexagonal films. Patterns form when the films release the
Pattern classification approaches to matching building polygons at multiple scales
Zhang, X; Zhao, X.; Molenaar, M.; Stoter, J.; Kraak M-J.; Ai, T.
2012-01-01
Matching of building polygons with different levels of detail is crucial in the maintenance and quality assessment of multi-representation databases. Two general problems need to be addressed in the matching process: (1) Which criteria are suitable? (2) How to effectively combine different criteria
Sub-wavelength resonances in polygonal metamaterial cylinders
DEFF Research Database (Denmark)
Arslanagic, Samel; Breinbjerg, Olav
2008-01-01
It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonical...
Exact Potts/Tutte polynomials for polygon chain graphs
Shrock, Robert
2011-04-01
We present exact calculations of Potts model partition functions and the equivalent Tutte polynomials for polygon chain graphs with open and cyclic boundary conditions. Special cases of the results that yield flow and reliability polynomials are discussed. We also analyze special cases of the Tutte polynomials that determine various quantities of graph-theoretic interest.
Searching a Polygonal Region by a Boundary Searcher
Institute of Scientific and Technical Information of China (English)
Xue-Hou Tan
2009-01-01
This paper considers the problem of planning the motion of a searcher in a polygonal region to eventually "see" an intruder that is unpredictable and capable of moving arbitrarily fast. A searcher is called the boundary searcher if he continuously moves on the polygon boundary and can see only along the rays of the flashlights he holds at a time.We present necessary and sufficient conditions for an n-sided polygon to be searchable by a boundary searcher. Based on our characterization, the equivalence of the ability of the searchers having only one flashlight and the one of the searchers having full 360° vision is simply established, and moreover, an optimal O(n) time and space algorithm for determining the searchability of simple polygons is obtained. We also give an O(n log n + I) time algorithm for generating a search schedule if it exists, where I (< 3n2) is the number of search instructions reported. Our results improve upon the previously known O(n2) time and space bounds.
Determination of wave direction from linear and polygonal arrays
Digital Repository Service at National Institute of Oceanography (India)
Fernandes, A.A.; Gouveia, A.D.; Nagarajan, R.
documentation of Borgman (1974) in case of linear arrays; and the second issue being the failure of Esteva (1976, 1977) to correctly determine wave directions over the design range 25 to 7 sec of his polygonal array. This paper presents requisite documentation...
Polygon formation and surface flow on a rotating fluid surface
DEFF Research Database (Denmark)
Bergmann, Raymond; Tophøj, Laust Emil Hjerrild; Homan, T. A. M.;
2011-01-01
We present a study of polygons forming on the free surface of a water flow confined to a stationary cylinder and driven by a rotating bottom plate as described by Jansson et al. (Phys. Rev. Lett., vol. 96, 2006, 174502). In particular, we study the case of a triangular structure, either completel...
Computing a Canonical Polygonal Schema of an Orientable Triangulated Surface
Lazarus, Francis; Pocchiola, Michel; Vegter, Gert; Verroust, Anne
2001-01-01
A closed orientable surface of genus g can be obtained by appropriate identification of pairs of edges of a 4g-gon (the polygonal schema). The identified edges form 2g loops on the surface, that are disjoint except for their common end-point. These loops are generators of both the fundamental group
Directory of Open Access Journals (Sweden)
Feng Qi
2014-10-01
Full Text Available The authors find the absolute monotonicity and complete monotonicity of some functions involving trigonometric functions and related to estimates the lower bounds of the first eigenvalue of Laplace operator on Riemannian manifolds.
Non-monotonic reasoning in conceptual modeling and ontology design: A proposal
CSIR Research Space (South Africa)
Casini, G
2013-06-01
Full Text Available and modeling of defeasible information and non-monotonic reasoning services. Here we formalize a possible way of introducing non-monotonic reasoning into ORM2 schemas, enriching the language with special set of new constraints....
The clique problem in ray intersection graphs
Langerman, Stefan; Cardinal, Jean; Cabello, Sergio
2015-01-01
Ray intersection graphs are intersection graphs of rays, or halflines, in the plane. We show that any planar graph has an even subdivision whose complement is a ray intersection graph. The construction can be done in polynomial time and implies that finding a maximum clique in a segment intersection graph is NP-hard. This solves a 21-year old open problem posed by Kratochvíl and Nešetřil (Comment Math Univ Carolinae 31(1):85-93, 1990).
DESIGNING AN EFFECTIVE INTERSECTION USING CAD ENVIRONMENT
Directory of Open Access Journals (Sweden)
CRISAN George-Horea
2017-05-01
Full Text Available Ensuring the safety and streamline in road traffic are very important aims, with regard to the nowadays people mobility level. Road infrastructure is an essential element that can meet these requirements. Thus, it is proposed to develop an effective model of intersection by using CAD software tools. This type of intersection can be successfully used on almost any category of roads, increasing road traffic safety, reducing passing times through the intersection and in the same time, reducing conflict points and increase the intersection capacity.
POLES OF ZETA FUNCTIONS OF COMPLETE INTERSECTIONS
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A vanishing theorem is proved for -adic cohomology with compact support on an affine (singular) complete intersection. As an application, it is shown that for an affine complete intersection defined over a finite field of q elements, the reciprocal "poles" of the zeta function are always divisible by q as algebraic integers. A p-adic proof is also given, which leads to further q-divisibility of the poles or equivalently an improvement of the polar part of the AxKatz theorem for an affine complete intersection. Similar results hold for a projective complete intersection.
Mixed Monotonicity of Partial First-In-First-Out Traffic Flow Models
Coogan, Samuel; Arcak, Murat; Kurzhanskiy, Alexander A.
2015-01-01
In vehicle traffic networks, congestion on one outgoing link of a diverging junction often impedes flow to other outgoing links, a phenomenon known as the first-in-first-out (FIFO) property. Simplified traffic models that do not account for the FIFO property result in monotone dynamics for which powerful analysis techniques exist. FIFO models are in general not monotone, but have been shown to be mixed monotone - a generalization of monotonicity that enables similarly powerful analysis techni...
Opposed turns at signalized intersections
Energy Technology Data Exchange (ETDEWEB)
Akcelik, R.
1989-06-01
The 1985 Highway Capacity Manual (HCM) brought the U.S. and Australian methodologies for signalized intersections closer together. An important element in this methodology is the techniques used for the estimation of opposed (permissive) turn saturation flows. Although the basic modeling philosophies of the HCM and Australian methods are similar, there are significant differences in the procedures used and therefore in the results from the two methods. In particular, the latest methodology employed in the SIDRA software has eliminated the use of opposed turn adjustment factors for lane groups and adopted an explicit and direct method of modeling individual lanes. The purpose of this paper is to bring these new methods to the attention of the U.S. researchers since it is understood that efforts are being made to improve the 1985 HCM method.
Tracks, intersections and dead ends
DEFF Research Database (Denmark)
Siim, Birte; Skjeie, Hege
2008-01-01
of organisations of civil society in political power. The second part explores the framing of the hijab as a political issue of "intersections" of gender equality versus religious belongings. The third part investigates what we see as a "dead end" in policy making to prevent violations of women's rights......The article discusses multicultural challenges to state feminism in Denmark and Norway focusing both on similarities and differences in the two countries policy responses. In spite of important differences, we point towards similar problems and dilemmas in the public responses to multiculturalism......; that is the general, age based, restrictions on family unification as a means to combat forced marriages. Finally, in the conclusion, we emphasise the importance of participatory women-friendly politics that include all who are affected by political decisions. ...
Monotonicity Formula and Regularity for General Free Discontinuity Problems
Bucur, Dorin; Luckhaus, Stephan
2014-02-01
We give a general monotonicity formula for local minimizers of free discontinuity problems which have a critical deviation from minimality, of order d - 1. This result allows us to prove partial regularity results (that is closure and density estimates for the jump set) for a large class of free discontinuity problems involving general energies associated to the jump set, as for example free boundary problems with Robin conditions. In particular, we give a short proof to the De Giorgi-Carriero-Leaci result for the Mumford-Shah functional.
The Non-Monotonic Effect of Financing Constraints on Investment
DEFF Research Database (Denmark)
Hirth, Stefan; Viswanatha, Marc
We analyze investment timing in a discrete-time framework with two possible investment dates, which is an extension of the model by Lyandres (2007). While Lyandres could only show non-monotonicity of investment in market frictions, we derive an investment threshold that is U-shaped in the firm's ......'s liquid funds, a result similar to the infinite-horizon model by Boyle and Guthrie (2003). However, due to the tractability of our model, we can more clearly explain the relevant trade-offs leading to the U-shape....
Contribution to the ergodic theory of piecewise monotone continuous maps
Faller, Bastien
2008-01-01
This thesis is devoted to the ergodic theory of the piecewise monotone continuous maps of the interval. The coding is a classical approach for these maps. Thanks to the coding, we get a symbolic dynamical system which is almost isomorphic to the initial dynamical system. The principle of the coding is very similar to the one of expansion of real numbers. We first define the coding in a perspective similar to the one of the expansions of real numbers; this perspective was already adopted by Ré...
Stability of generalized monotonicity with respect to their characterizations
An, P T
2002-01-01
We show that known types of generalized monotone maps are not stable with respect to their characterizations (i.e., the characterizations are not maintained during an arbitrary map of this type is disturbed by an element with sufficiently small norm) then introduce s-quasimonotone maps, which are stable with respect to their characterization. For gradient maps, s-quasimonotonicity is related to s-quasiconvexity of the underlying function. A necessary and sufficient condition for a univariate polynomial to be s-quasimonotone is given. Furthermore, some stability properties of a-quasiconvex functions are presented.
Deterministic homogenization of parabolic monotone operators with time dependent coefficients
Directory of Open Access Journals (Sweden)
Gabriel Nguetseng
2004-06-01
Full Text Available We study, beyond the classical periodic setting, the homogenization of linear and nonlinear parabolic differential equations associated with monotone operators. The usual periodicity hypothesis is here substituted by an abstract deterministic assumption characterized by a great relaxation of the time behaviour. Our main tool is the recent theory of homogenization structures by the first author, and our homogenization approach falls under the two-scale convergence method. Various concrete examples are worked out with a view to pointing out the wide scope of our approach and bringing the role of homogenization structures to light.
Framing Gender Intersections in the European Union
DEFF Research Database (Denmark)
Lombardo, Emanuela; Agustin, Lise Rolandsen
2012-01-01
This article explores the extent to which the emergence of an antidiscrimination policy in the European Union (EU) implies a shift in EU gender equality policies towards an intersectional approach. The frame analysis of EU gender equality policy documents shows that intersectional dimensions...
Computations in intersection rings of flag bundles
Grayson, Daniel R; Stillman, Michael E
2012-01-01
Intersection rings of flag varieties and of isotropic flag varieties are generated by Chern classes of the tautological bundles modulo the relations coming from multiplicativity of total Chern classes. In this paper we describe the Groebner bases of the ideals of relations and give applications to computation of intersections, as implemented in Macaulay2.
Framing Gender Intersections in the European Union
DEFF Research Database (Denmark)
Lombardo, Emanuela; Agustin, Lise Rolandsen
2012-01-01
This article explores the extent to which the emergence of an antidiscrimination policy in the European Union (EU) implies a shift in EU gender equality policies towards an intersectional approach. The frame analysis of EU gender equality policy documents shows that intersectional dimensions...
On Polygons Admitting a Simson Line as Discrete Analogs of Parabolas
Tsukerman, Emmanuel
2012-01-01
We begin by proving a few general facts about Simson polygons, defined as polygons which admit a pedal line. We use an inductive argument to show that no convex $n$-gon, $n\\geq5$, admits a Simson Line. We then determine a property which characterizes Simson $n$-gons and show that one can be constructed for every $n\\geq3$. We proceed to show that a parabola can be viewed as a limit of special Simson polygons, called equidistant Simson polygons, and that these polygons provide the best piecewise linear continuous approximation to the parabola. Finally, we show that equidistant Simson polygons can be viewed as discrete analogs of parabolas and that they satisfy a number of results analogous to the pedal property, optical property, properties of Archimedes triangles and Lambert's Theorem of parabolas. The corresponding results for parabolas are easily obtained by applying a limit process to the equidistant Simson polygons.
Stone Polygons: Self-Organization Assisted by Noise
Fang, M.; Hager, B. H.
2002-12-01
Polygonal patterns formed by sorted gravel are commonly found on flat surfaces where water drainage is poor because of underlying permafrost. The similarity in pattern of these stone polygons with Rayleigh-Benard thermal convection cells is intriguing. There is even a suggestion that stone polygons are formed by Rayleigh-Benard convection of water through the underlying porous soil (Kranz et al, 1983). Recent developments in understanding the microphysical mechanisms of frost heaving (e.g. Wettlaufer, 1999; Zhu et al 2000) reinforce the conventional view that the freeze-thawing cycle of ice is the primary natural agent for this pattern formation. Mathematically, a large body of solutions to problems in pattern formation can be attributed to the reaction-diffusion system. There is a subtle difference, however, between systems like Rayleigh-Benard convection cells and stone polygons: The latter are formed in a noisy natural environment, the former in a highly controlled laboratory environment. In other words, the effects of large sources of noise must be accounted for explicitly in understanding the pattern formation of stone polygons. A distribution of stone polygons formed cooperatively results from sorting among water, soil, and stones controlled by weather changes. We propose a nonlinear reaction-diffusion type of model for this coupled process. We consider the incremental population density of stones (positive or negative relative to the initial uniform distribution). The positive feedback between freeze-thaw cycles and the local stone accumulation (positive or negative) is modeled by a linear production term, while the gravitational reconfiguration gives rise to a cubic nonlinear saturation term. Noise due to fluctuations of the environment is represented by the diffusion term. Similar systems have emerged in wide ranges of physical and chemical problems, yet most of the investigations in the other fields are on stability fields associated with varying control
An intersection algorithm based on transformation
Institute of Scientific and Technical Information of China (English)
CHEN Xiao-xia; YONG Jun-hai; CHEN Yu-jian
2006-01-01
How to obtain intersection of curves and surfaces is a fundamental problem in many areas such as computer graphics,CAD/CAM,computer animation,and robotics.Especially,how to deal with singular cases,such as tangency or superposition,is a key problem in obtaining intersection results.A method for solving the intersection problem based on the coordinate transformation is presented.With the Lagrange multiplier method,the minimum distance between the center of a circle and a quadric surface is given as well.Experience shows that the coordinate transformation could significantly simplify the method for calculating intersection to the tangency condition.It can improve the stability of the intersection of given curves and surfaces in singularity cases.The new algorithm is applied in a three dimensional CAD software (GEMS),produced by Tsinghua University.
A Neurodynamic Model to Solve Nonlinear Pseudo-Monotone Projection Equation and Its Applications.
Eshaghnezhad, Mohammad; Effati, Sohrab; Mansoori, Amin
2016-09-29
In this paper, a neurodynamic model is given to solve nonlinear pseudo-monotone projection equation. Under pseudo-monotonicity condition and Lipschitz continuous condition, the projection neurodynamic model is proved to be stable in the sense of Lyapunov, globally convergent, globally asymptotically stable, and globally exponentially stable. Also, we show that, our new neurodynamic model is effective to solve the nonconvex optimization problems. Moreover, since monotonicity is a special case of pseudo-monotonicity and also since a co-coercive mapping is Lipschitz continuous and monotone, and a strongly pseudo-monotone mapping is pseudo-monotone, the neurodynamic model can be applied to solve a broader classes of constrained optimization problems related to variational inequalities, pseudo-convex optimization problem, linear and nonlinear complementarity problems, and linear and convex quadratic programming problems. Finally, several illustrative examples are stated to demonstrate the effectiveness and efficiency of our new neurodynamic model.
Testing monotonicity of a hazard: asymptotic distribution theory
Groeneboom, Piet
2011-01-01
Two new test statistics are introduced to test the null hypotheses that the sampling distribution has an increasing hazard rate on a specified interval [0,a]. These statistics are empirical L_1-type distances between the isotonic estimates, which use the monotonicity constraint, and either the empirical distribution function or the empirical cumulative hazard. They measure the excursions of the empirical estimates with respect to the isotonic estimates, due to local non-monotonicity. Asymptotic normality of the test statistics, if the hazard is strictly increasing on [0,a], is established under mild conditions. This is done by first approximating the global empirical distance by an distance with respect to the underlying distribution function. The resulting integral is treated as sum of increasingly many local integrals to which a CLT can be applied. The behavior of the local integrals is determined by a canonical process: the difference between the stochastic process x -> W(x)+x^2 where W is standard two-sid...
DATA PREORDERING IN GENERALIZED PAV ALGORITHM FOR MONOTONIC REGRESSION
Institute of Scientific and Technical Information of China (English)
Oleg Burdakov; Anders Grimvall; Oleg Sysoev
2006-01-01
Monotonic regression (MR) is a least distance problem with monotonicity constraints induced by a partially ordered data set of observations. In our recent publication [In Ser.Nonconvex Optimization and Its Applications, Springer-Verlag, (2006) 83, pp. 25-33],the Pool-Adjacent-Violators algorithm (PAV) was generalized from completely to partially ordered data sets (posets). The new algorithm, called GPAV, is characterized by the very low computational complexity, which is of second order in the number of observations.It treats the observations in a consecutive order, and it can follow any arbitrarily chosen topological order of the poset of observations. The GPAV algorithm produces a sufficiently accurate solution to the MR problem, but the accuracy depends on the chosen topological order. Here we prove that there exists a topological order for which the resulted GPAV solution is optimal. Furthermore, we present results of extensive numerical experiments,from which we draw conclusions about the most and the least preferable topological orders.
The Toric Geometry of Triangulated Polygons in Euclidean Space
Howard, Benjamin; Millson, John
2008-01-01
Speyer and Sturmfels [SpSt] associated Gr\\"obner toric degenerations $\\mathrm{Gr}_2(\\C^n)^{\\tree}$ of $\\mathrm{Gr}_2(\\C^n)$ to each trivalent tree $\\tree$ with $n$ leaves. These degenerations induce toric degenerations $M_{\\br}^{\\tree}$ of $M_{\\br}$, the space of $n$ ordered, weighted (by $\\br$) points on the projective line. Our goal in this paper is to give a geometric (Euclidean polygon) description of the toric fibers as stratified symplectic spaces and describe the action of the compact part of the torus as "bendings of polygons." We prove the conjecture of Foth and Hu [FH] that the toric fibers are homeomorphic to the spaces defined by Kamiyama and Yoshida [KY].
QUADRATIC SERENDIPITY FINITE ELEMENTS ON POLYGONS USING GENERALIZED BARYCENTRIC COORDINATES.
Rand, Alexander; Gillette, Andrew; Bajaj, Chandrajit
2014-01-01
We introduce a finite element construction for use on the class of convex, planar polygons and show it obtains a quadratic error convergence estimate. On a convex n-gon, our construction produces 2n basis functions, associated in a Lagrange-like fashion to each vertex and each edge midpoint, by transforming and combining a set of n(n + 1)/2 basis functions known to obtain quadratic convergence. The technique broadens the scope of the so-called 'serendipity' elements, previously studied only for quadrilateral and regular hexahedral meshes, by employing the theory of generalized barycentric coordinates. Uniform a priori error estimates are established over the class of convex quadrilaterals with bounded aspect ratio as well as over the class of convex planar polygons satisfying additional shape regularity conditions to exclude large interior angles and short edges. Numerical evidence is provided on a trapezoidal quadrilateral mesh, previously not amenable to serendipity constructions, and applications to adaptive meshing are discussed.
An Operator Product Expansion for Polygonal null Wilson Loops
Alday, Luis F; Maldacena, Juan; Sever, Amit; Vieira, Pedro
2010-01-01
We consider polygonal Wilson loops with null edges in conformal gauge theories. We derive an OPE-like expansion when several successive lines of the polygon are becoming aligned. The limit corresponds to a collinear, or multicollinear, limit and we explain the systematics of all the subleading corrections, going beyond the leading terms that were previously considered. These subleading corrections are governed by excitations of high spin operators, or excitations of a flux tube that goes between two Wilson lines. The discussion is valid for any conformal gauge theory, for any coupling and in any dimension. For N=4 super Yang Mills we check this expansion at strong coupling and at two loops at weak coupling . We also make predictions for the remainder function at higher loops. In the process, we also derived a new version for the TBA integral equations that determine the strong coupling answer and present the area as the associated Yang-Yang functional.
Intracranial meningioma with polygonal granular cell appearance in a Chihuahua.
Takeuchi, Yoshinori; Ohnishi, Yumi; Matsunaga, Satoru; Nakayama, Hiroyuki; Uetsuka, Koji
2008-05-01
A menigioma with polygonal granular cell proliferation in an 11-year and 8-month-old male Chihuahua is described. The tumor was observed under the dura matter of the right cerebrum. Microscopically, the tumor consisted of solid growth foci of small- or large- sized polygonal cells, with pale-stained nuclei, prominent nucleoli, and fine granular to foamy eosinophilic cytoplasm. Some of the proliferating cells contained variable amounts of cytoplasmic PAS-positive granules. Immunohistochemical analysis revealed that neoplastic cells were positive for vimentin and S-100 protein. Ultrastructurally, the neoplastic cells contained vesicular structures with a few small round-shaped bodies in the cytoplasm. We diagnosed the case as canine meningioma with granular cell appearance.
Fat polygonal partitions with applications to visualization and embeddings
Directory of Open Access Journals (Sweden)
Mark de Berg
2013-12-01
Full Text Available Let T be a rooted and weighted tree, where the weight of any node is equal to the sum of the weights of its children. The popular Treemap algorithm visualizes such a tree as a hierarchical partition of a square into rectangles, where the area of the rectangle corresponding to any node in T is equal to the weight of that node. The aspect ratio of the rectangles in such a rectangular partition necessarily depends on the weights and can become arbitrarily high.We introduce a new hierarchical partition scheme, called a polygonal partition, which uses convex polygons rather than just rectangles. We present two methods for constructing polygonal partitions, both having guarantees on the worst-case aspect ratio of the constructed polygons; in particular, both methods guarantee a bound on the aspect ratio that is independent of the weights of the nodes.We also consider rectangular partitions with slack, where the areas of the rectangles may differ slightly from the weights of the corresponding nodes. We show that this makes it possible to obtain partitions with constant aspect ratio. This result generalizes to hyper-rectangular partitions in ℝd. We use these partitions with slack for embedding ultrametrics into d-dimensional Euclidean space: we give a polylog(Δ-approximation algorithm for embedding n-point ultrametrics into ℝd with minimum distortion, where Δ denotes the spread of the metric. The previously best-known approximation ratio for this problem was polynomial in n. This is the first algorithm for embedding a non-trivial family of weighted-graph metrics into a space of constant dimension that achieves polylogarithmic approximation ratio.
Robust design of a polygonal shaft-hub coupling
Directory of Open Access Journals (Sweden)
R. Citarella
2015-10-01
Full Text Available In this work, the Taguchi method is applied for the optimal choice of design parameter values for a polygonal shaft-hub coupling. The objective is to maximize a performance function, minimizing, at the same time, its sensitivity to noises factors (robust design. The Design of Experiments (DoE is adopted to set up a plan of numerical experiments, whose different configurations are simulated using the Boundary Element Method (BEM
Dominant Mode Wave Impedance of Regular Polygonal Waveguides
Directory of Open Access Journals (Sweden)
Vyacheslav V. Komarov
2014-01-01
Full Text Available Polygonal metal waveguides are analyzed analytically and numerically. Classical equation for the wave impedance of arbitrary shaped waveguides is completed with approximate expression for the cutoff wavelength of the dominant mode. Proposed approach is tested with the help of 3D finite difference time domain models of microwave waveguides junctions. Obtained data are used for computer-aided design of microwave transition from coaxial line to cylindrical waveguide.
Quantum Algorithmic Integrability The Metaphor of Polygonal Billiards
Mantica, G
1999-01-01
An elementary application of Algorithmic Complexity Theory to the polygonal approximations of curved billiards-integrable and chaotic-unveils the equivalence of this problem to the procedure of quantization of classical systems: the scaling relations for the average complexity of symbolic trajectories are formally the same as those governing the semi-classical limit of quantum systems. Two cases-the circle, and the stadium-are examined in detail, and are presented as paradigms.
The Area of a Polygon with an Inscribed Circle
Buck, Marshall W
2012-01-01
Heron's formula states that the area $K$ of a triangle with sides $a$, $b$, and $c$ is given by $$ K=\\sqrt {s(s-a) (s-b) (s-c)} $$ where $s$ is the semiperimeter $(a+b+c)/2$. Brahmagupta, Robbins, Roskies, and Maley generalized this formula for polygons of up to eight sides inscribed in a circle. In this paper we derive formulas giving the areas of any $n$-gon, with odd $n$, in terms of the ordered list of side lengths, if the $n$-gon is circumscribed about a circle (instead of being inscribed in a circle). Unlike the cyclic polygon problem, where the order of the sides does not matter, for the inscribed circle problem (our case) it does matter. The solution is much easier than for the cyclic polygon problem, but it does generalize easily to all odd $n$. We also provide necessary and sufficient conditions for there to be solutions in the case of even $n$.
Synthesis and characterisation of polygonal indium tin oxide nanocrystals.
Koo, Bon-Ryul; Park, Byung Kyu; Kim, Chang Yeoul; Oh, Sung-Tag; Ahn, Hyo-Jin
2013-11-01
Polygon ITO (Sn-doped In2O3) nanocrystals were synthesised via electrospinning, and their morphology, structural properties, and chemical composition were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). To determine the optimum conditions for the fabrication of polygon ITO nanocrystals, calcination temperature after the electrospinning process was controlled at 500 degrees C, 600 degrees C, 700 degrees C, and 800 degrees C, and the amount of PVP polymer was controlled at 4 wt%, 7 wt%, and 10 wt%. For comparison purposes, single In2O3 nanocrystals were also synthesised via electrospinning and calcination. The results show that ITO nanocrystals fabricated at a calcination temperature of 800 degrees C and with 10 wt% of PVP polymer exhibit clear polygon structure with single-crystallinity, which may be explained in terms of the effect of Sn doping in the In2O3 matrix and the oriented aggregation and Oswald ripening growth during the fusion process of ITO nanocrystals.
Special properties of Eshelby tensor for a regular polygonal inclusion
Institute of Scientific and Technical Information of China (English)
Baixiang Xu; Minzhong Wang
2005-01-01
When studying the regular polygonal inclusion in 1997, Nozaki and Taya discovered numerically some remarkable properties of Eshelby tensor: Eshelby tensor at the center and the averaged Eshelby tensor over the inclusion domain are equal to that of a circular inclusion and independent of the orientation of the inclusion. Then Kawashita and Nozaki justified the properties mathematically. In the present paper, some other properties of a regular polygonal inclusion are discovered. We find that for an N-fold regular polygonal inclusion except for a square, the arithmetic mean of Eshelby tensors at N rotational symmetrical points in the inclusion is also equal to the Eshelby tensor for a circular inclusion and independent of the orientation of the inclusion. Furthermore,in two corollaries, we point out that Eshelby tensor at the center, the averaged Eshelby tensor over the inclusion domain,and the line integral average of Eshelby tensors along any concentric circle of the inclusion are all identical with the arithmetic mean.
At the Intersection of Identities
Directory of Open Access Journals (Sweden)
Hidasi Judit
2016-12-01
Full Text Available It is assumed that part of today’s societal difficulties, uncertainties and crisis worldwide can be attributed to the competing of multiple identities, to their intersections and their overlapping nature – on the level of nations, on the level of communities and also on the level of the individual. We aim at presenting a typology of identities that come into play in the public and in the private domain of the individual. It is hypothesized that there is a strong interdependence of cultural heritage, human values and social traditions in the competition of identities. These questions, which are interrelated and interconnected with each other through a common denominator, namely “cultural-mental programming” and “reprogramming efforts,” are going to be pondered about in the presentation. In the context of globalization the relevance of this topic is reinforced by the need to adapt to changes within the ever-intensifying shift from intercultural to multicultural environment in communities, in business and in work places. Attempts will be made to articulate some projections with respect to future trends that are to be expected: the way to go from competing identities to establishing a competitive identity (Simon Anholt. The contribution does not offer ready solutions but rather serves as fuel for further discussions.
Session Types = Intersection Types + Union Types
Padovani, Luca
2011-01-01
We propose a semantically grounded theory of session types which relies on intersection and union types. We argue that intersection and union types are natural candidates for modeling branching points in session types and we show that the resulting theory overcomes some important defects of related behavioral theories. In particular, intersections and unions provide a native solution to the problem of computing joins and meets of session types. Also, the subtyping relation turns out to be a pre-congruence, while this is not always the case in related behavioral theories.
Elastic waves along a fracture intersection
Abell, Bradley Charles
Fractures and fracture networks play a significant role in the subsurface hydraulic connectivity within the Earth. While a significant amount of research has been performed on the seismic response of single fractures and sets of fractures, few studies have examined the effect of fracture intersections on elastic wave propagation. Intersections play a key role in the connectivity of a fracture network that ultimately affects the hydraulic integrity of a rock mass. In this dissertation two new types of coupled waves are examined that propagate along intersections. 1) A coupled wedge wave that propagates along a surface fracture with particle motion highly localized to the intersection of a fracture with a free surface, and 2) fracture intersection waves that propagate along the intersection between two orthogonal fractures. Theoretical formulations were derived to determine the particle motion and velocity of intersection waves. Vibrational modes calculated from the theoretical formulation match those predicted by group theory based on the symmetry of the problem. For the coupled wedge wave, two vibrational modes exist that range in velocity between the wedge wave and Rayleigh wave velocity and exhibit either wagging or breathing motion depending on the Poisson's ratio. For the intersection waves, the observed modes depend on the properties of the fractures forming the intersection. If both fractures have equal stiffness four modes exist, two with wagging and two with breathing motion. If the fractures have unequal stiffness, four modes also exist, but the motion depends on the Poisson's ratio. The velocity of intersection waves depends on the coupling or stiffness of the intersection and frequency of the signal. In general, the different modes travel with speeds between the wedge wave and bulk shear wave velocity. Laboratory experiments were performed on isotropic and anisotropic samples to verify the existence of these waves. For both waves, the observed signals
Conical intersections in an ultracold gas
Wüster, S; Rost, J M
2010-01-01
We find that energy surfaces of more than two atoms or molecules interacting via dipole-dipole po- tentials generically possess conical intersections (CIs). Typically only few atoms participate strongly in such an intersection. For the fundamental case, a circular trimer, we show how the CI affects adiabatic excitation transport via electronic decoherence or geometric phase interference. These phe- nomena may be experimentally accessible if the trimer is realized by light alkali atoms in a ring trap, whose dipole-dipole interactions are induced by off-resonant dressing with Rydberg states. Such a setup promises a direct probe of the full many-body density dynamics near a conical intersection.
On minimal energy dipole moment distributions in regular polygonal agglomerates
Rosa, Adriano Possebon; Cunha, Francisco Ricardo; Ceniceros, Hector Daniel
2017-01-01
Static, regular polygonal and close-packed clusters of spherical magnetic particles and their energy-minimizing magnetic moments are investigated in a two-dimensional setting. This study focuses on a simple particle system which is solely described by the dipole-dipole interaction energy, both without and in the presence of an in-plane magnetic field. For a regular polygonal structure of n sides with n ≥ 3 , and in the absence of an external field, it is proved rigorously that the magnetic moments given by the roots of unity, i.e. tangential to the polygon, are a minimizer of the dipole-dipole interaction energy. Also, for zero external field, new multiple local minima are discovered for the regular polygonal agglomerates. The number of found local extrema is proportional to [ n / 2 ] and these critical points are characterized by the presence of a pair of magnetic moments with a large deviation from the tangential configuration and whose particles are at least three diameters apart. The changes induced by an in-plane external magnetic field on the minimal energy, tangential configurations are investigated numerically. The two critical fields, which correspond to a crossover with the linear chain minimal energy and with the break-up of the agglomerate, respectively are examined in detail. In particular, the numerical results are compared directly with the asymptotic formulas of Danilov et al. (2012) [23] and a remarkable agreement is found even for moderate to large fields. Finally, three examples of close-packed structures are investigated: a triangle, a centered hexagon, and a 19-particle close packed cluster. The numerical study reveals novel, illuminating characteristics of these compact clusters often seen in ferrofluids. The centered hexagon is energetically favorable to the regular hexagon and the minimal energy for the larger 19-particle cluster is even lower than that of the close packed hexagon. In addition, this larger close packed agglomerate has two
The regularized monotonicity method: detecting irregular indefinite inclusions
DEFF Research Database (Denmark)
Garde, Henrik; Staboulis, Stratos
2017-01-01
In inclusion detection in electrical impedance tomography, the support of perturbations (inclusion) from a known background conductivity is typically reconstructed from idealized continuum data modelled by a Neumann-to-Dirichlet map. Only few reconstruction methods apply when detecting indefinite...... of approximative measurement models, including the Complete Electrode Model, hence making the method robust against modelling error and noise. In particular, we demonstrate that for a convergent family of approximative models there exists a sequence of regularization parameters such that the outer shape...... of the inclusions is asymptotically exactly characterized. Finally, a peeling-type reconstruction algorithm is presented and, for the first time in literature, numerical examples of monotonicity reconstructions for indefinite inclusions are presented....
Convex analysis and monotone operator theory in Hilbert spaces
Bauschke, Heinz H
2017-01-01
This reference text, now in its second edition, offers a modern unifying presentation of three basic areas of nonlinear analysis: convex analysis, monotone operator theory, and the fixed point theory of nonexpansive operators. Taking a unique comprehensive approach, the theory is developed from the ground up, with the rich connections and interactions between the areas as the central focus, and it is illustrated by a large number of examples. The Hilbert space setting of the material offers a wide range of applications while avoiding the technical difficulties of general Banach spaces. The authors have also drawn upon recent advances and modern tools to simplify the proofs of key results making the book more accessible to a broader range of scholars and users. Combining a strong emphasis on applications with exceptionally lucid writing and an abundance of exercises, this text is of great value to a large audience including pure and applied mathematicians as well as researchers in engineering, data science, ma...
Monotonic childhoods: representations of otherness in research writing
Directory of Open Access Journals (Sweden)
Denise Marcos Bussoletti
2011-12-01
Full Text Available This paper is part of a doctoral thesis entitled “Monotonic childhoods – a rhapsody of hope”. It follows the perspective of a critical psychosocial and cultural study, and aims at discussing the other’s representation in research writing, electing childhood as an allegorical and refl ective place. It takes into consideration, by means of analysis, the drawings and poems of children from the Terezin ghetto during the Second World War. The work is mostly based on Serge Moscovici’s Social Representation Theory, but it is also in constant dialogue with other theories and knowledge fi elds, especially Walter Benjamin’s and Mikhail Bakhtin’s contributions. At the end, the paper supports the thesis that conceives poetics as one of the translation axes of childhood cultures.
PPA BASED PREDICTION-CORRECTION METHODS FOR MONOTONE VARIATIONAL INEQUALITIES
Institute of Scientific and Technical Information of China (English)
He Bingsheng; Jiang Jianlin; Qian Maijian; Xu Ya
2005-01-01
In this paper we study the proximal point algorithm (PPA) based predictioncorrection (PC) methods for monotone variational inequalities. Each iteration of these methods consists of a prediction and a correction. The predictors are produced by inexact PPA steps. The new iterates are then updated by a correction using the PPA formula. We present two profit functions which serve two purposes: First we show that the profit functions are tight lower bounds of the improvements obtained in each iteration. Based on this conclusion we obtain the convergence inexactness restrictions for the prediction step. Second we show that the profit functions are quadratically dependent upon the step lengths, thus the optimal step lengths are obtained in the correction step. In the last part of the paper we compare the strengths of different methods based on their inexactness restrictions.
Strong convergence theorems for maximal monotone mappings in Banach spaces
Zegeye, Habtu
2008-07-01
Let E be a uniformly convex and 2-uniformly smooth real Banach space with dual E*. Let be a Lipschitz continuous monotone mapping with A-1(0)[not equal to][empty set]. For given u,x1[set membership, variant]E, let {xn} be generated by the algorithm xn+1:=[beta]nu+(1-[beta]n)(xn-[alpha]nAJxn), n[greater-or-equal, slanted]1, where J is the normalized duality mapping from E into E* and {[lambda]n} and {[theta]n} are real sequences in (0,1) satisfying certain conditions. Then it is proved that, under some mild conditions, {xn} converges strongly to x*[set membership, variant]E where Jx*[set membership, variant]A-1(0). Finally, we apply our convergence theorems to the convex minimization problems.
Convergence of the natural approximations of piecewise monotone interval maps.
Haydn, Nicolai
2004-06-01
We consider piecewise monotone interval mappings which are topologically mixing and satisfy the Markov property. It has previously been shown that the invariant densities of the natural approximations converge exponentially fast in uniform pointwise topology to the invariant density of the given map provided its derivative is piecewise Lipshitz continuous. We provide an example of a map which is Lipshitz continuous and for which the densities converge in the bounded variation norm at a logarithmic rate. This shows that in general one cannot expect exponential convergence in the bounded variation norm. Here we prove that if the derivative of the interval map is Holder continuous and its variation is well approximable (gamma-uniform variation for gamma>0), then the densities converge exponentially fast in the norm.
A COMPARISON OF DIFFERENT CONTRACTION METHODS FOR MONOTONE VARIATIONAL INEQUALITIES
Institute of Scientific and Technical Information of China (English)
Bingsheng He; Xiang Wang; Junfeng Yang
2009-01-01
It is interesting to compare the efficiency of two methods when their computational loads in each iteration are equal. In this paper, two classes of contraction methods for monotone variational inequalities are studied in a unified framework. The methods of both classes can be viewed as prediction-correction methods, which generate the same test vector in the prediction step and adopt the same step-size rule in the correction step. The only difference is that they use different search directions. The computational loads of each iteration of the different classes are equal. Our analysis explains theoretically why one class of the contraction methods usually outperforms the other class. It is demonstrated that many known methods belong to these two classes of methods. Finally, the presented numerical results demonstrate the validity of our analysis.
A new non-monotone fitness scaling for genetic algorithm
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The properties of selection operators in the genetic algorithm (GA) are studied in detail. It is indicated that the selection of operations is significant for both improving the general fitness of a population and leading to the schema deceptiveness. The stochastic searching characteristics of GA are compared with those of heuristic methods. The influence of selection operators on the GA' s exploration and exploitation is discussed, and the performance of selection operators is evaluated with the premature convergence of the GA taken as an example based on One-Max function. In order to overcome the schema deceptiveness of the GA, a new type of fitness scaling, non monotone scaling, is advanced to enhance the evolutionary ability of a population. The effectiveness of the new scaling method is tested by a trap function and a needle-in-haystack (NiH) function.
MINLIP for the Identification of Monotone Wiener Systems
Pelckmans, Kristiaan
2010-01-01
This paper studies the MINLIP estimator for the identification of Wiener systems consisting of a sequence of a linear FIR dynamical model, and a monotonically increasing (or decreasing) static function. Given $T$ observations, this algorithm boils down to solving a convex quadratic program with $O(T)$ variables and inequality constraints, implementing an inference technique which is based entirely on model complexity control. The resulting estimates of the linear submodel are found to be almost consistent when no noise is present in the data, under a condition of smoothness of the true nonlinearity and local Persistency of Excitation (local PE) of the data. This result is novel as it does not rely on classical tools as a 'linearization' using a Taylor decomposition, nor exploits stochastic properties of the data. It is indicated how to extend the method to cope with noisy data, and empirical evidence contrasts performance of the estimator against other recently proposed techniques.
A new approximate proximal point algorithm for maximal monotone operator
Institute of Scientific and Technical Information of China (English)
HE; Bingsheng(何炳生); LIAO; Lizhi(廖立志); YANG; Zhenhua(杨振华)
2003-01-01
The problem concerned in this paper is the set-valued equation 0 ∈ T(z) where T is a maximal monotone operator. For given xk and βk ＞ 0, some existing approximate proximal point algorithms take xk+1 = xk such that xk +ek∈ xk + βkT(xk) and||ek|| ≤ηk||xk - xk||, where {ηk} is a non-negative summable sequence. Instead of xk+1 = xk, the new iterate of the proposing method is given by xk+1 = PΩ[xk - ek], where Ω is the domain of T and PΩ(@) denotes the projection on Ω. The convergence is proved under a significantly relaxed restriction supk＞0 ηk ＜ 1.
Payoff-monotonic game dynamics and the maximum clique problem.
Pelillo, Marcello; Torsello, Andrea
2006-05-01
Evolutionary game-theoretic models and, in particular, the so-called replicator equations have recently proven to be remarkably effective at approximately solving the maximum clique and related problems. The approach is centered around a classic result from graph theory that formulates the maximum clique problem as a standard (continuous) quadratic program and exploits the dynamical properties of these models, which, under a certain symmetry assumption, possess a Lyapunov function. In this letter, we generalize previous work along these lines in several respects. We introduce a wide family of game-dynamic equations known as payoff-monotonic dynamics, of which replicator dynamics are a special instance, and show that they enjoy precisely the same dynamical properties as standard replicator equations. These properties make any member of this family a potential heuristic for solving standard quadratic programs and, in particular, the maximum clique problem. Extensive simulations, performed on random as well as DIMACS benchmark graphs, show that this class contains dynamics that are considerably faster than and at least as accurate as replicator equations. One problem associated with these models, however, relates to their inability to escape from poor local solutions. To overcome this drawback, we focus on a particular subclass of payoff-monotonic dynamics used to model the evolution of behavior via imitation processes and study the stability of their equilibria when a regularization parameter is allowed to take on negative values. A detailed analysis of these properties suggests a whole class of annealed imitation heuristics for the maximum clique problem, which are based on the idea of varying the parameter during the imitation optimization process in a principled way, so as to avoid unwanted inefficient solutions. Experiments show that the proposed annealing procedure does help to avoid poor local optima by initially driving the dynamics toward promising regions in
Optimising Signalised Intersection Using Wireless Vehicle Detectors
DEFF Research Database (Denmark)
Adjin, Daniel Michael Okwabi; Torkudzor, Moses; Asare, Jack
Traffic congestion on roads wastes travel times. In this paper, we developed a vehicular traffic model to optimise a signalised intersection in Accra, using wireless vehicle detectors. Traffic volume gathered was extrapolated to cover 2011 and 2016 and were analysed to obtain the peak hour traffic...... volume causing congestion. The intersection was modelled and simulated in Synchro7 as an actuated signalised model using results from the analysed data. The model for morning peak periods gave optimal cycle lengths of 100s and 150s with corresponding intersection delay of 48.9s and 90.6s in 2011 and 2016...... respectively while that for the evening was 55s giving delay of 14.2s and 16.3s respectively. It is shown that the model will improve traffic flow at the intersection....
Hirzebruch-Milnor classes of complete intersections
Maxim, Laurentiu; Schuermann, Joerg
2012-01-01
We prove a new formula for the Hirzebruch-Milnor classes of global complete intersections with arbitrary singularities describing the difference between the Hirzebruch classes and the virtual ones. This generalizes a formula for the Chern-Milnor classes in the hypersurface case that was conjectured by S. Yokura and was proved by A. Parusinski and P. Pragacz. It also generalizes a formula of T. Suwa for the Chern-Milnor classes of complete intersections with isolated singularities.
Self-Localization at Street Intersections.
Fusco, Giovanni; Shen, Huiying; Coughlan, James M
2014-05-01
There is growing interest among smartphone users in the ability to determine their precise location in their environment for a variety of applications related to wayfinding, travel and shopping. While GPS provides valuable self-localization estimates, its accuracy is limited to approximately 10 meters in most urban locations. This paper focuses on the self-localization needs of blind or visually impaired travelers, who are faced with the challenge of negotiating street intersections. These travelers need more precise self-localization to help them align themselves properly to crosswalks, signal lights and other features such as walk light pushbuttons. We demonstrate a novel computer vision-based localization approach that is tailored to the street intersection domain. Unlike most work on computer vision-based localization techniques, which typically assume the presence of detailed, high-quality 3D models of urban environments, our technique harnesses the availability of simple, ubiquitous satellite imagery (e.g., Google Maps) to create simple maps of each intersection. Not only does this technique scale naturally to the great majority of street intersections in urban areas, but it has the added advantage of incorporating the specific metric information that blind or visually impaired travelers need, namely, the locations of intersection features such as crosswalks. Key to our approach is the integration of IMU (inertial measurement unit) information with geometric information obtained from image panorama stitchings. Finally, we evaluate the localization performance of our algorithm on a dataset of intersection panoramas, demonstrating the feasibility of our approach.
Optimal Polygonal Approximation of Digital Planar Curves Using Genetic Algorithm and Tabu Search
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Three heuristic algorithms for optimal polygonal approximation of digital planar curves is presented.With Genetic Algorithm (GA), improved Genetic Algorithm (IGA) based on Pareto optimal solution and Tabu Search (TS), a near optimal polygonal approximation was obtained.Compared to the famous Teh-chin algorithm, our algorithms have obtained the approximated polygons with less number of vertices and less approximation error.Compared to the dynamic programming algorithm, the processing time of our algorithms are much less expensive.
A new definition and calculation for the average normal to a polygon
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This paper presents a new definition of the average normal to a polygon by introducing a cone bounded by the polygon, computing its normals and averaging the result. The equivalence of this new definition and that of Newell's is given, and a simple calculation based on this new definition is obtained and 3N additions and N subtractions are saved, where N is the number of the vertices of the polygon.
A new definition and calculation for the average normal to a polygon
Institute of Scientific and Technical Information of China (English)
梁友栋
2000-01-01
This paper presents a new definition of the average normal to a polygon by introducing a cone bounded by the polygon, computing its normals and averaging the result. The equivalence of this new definition and that of Newell’s is given, and a simple calculation based on this new definition is obtained and 3 N additions and N subtractions are saved, where N is the number of the vertices of the polygon.
Strong Stationary Duality for M\\"obius Monotone Markov Chains: Unreliable Networks
Lorek, Pawel
2011-01-01
For Markov chains with a partially ordered finite state space we show strong stationary duality under the condition of M\\"obius monotonicity of the chain. We show relations of M\\"obius monotonicity to other definitions of monotone chains. We give examples of dual chains in this context which have transitions only upwards. We illustrate general theory by an analysis of nonsymmetric random walks on the cube with an application to networks of queues.
On a correspondence between regular and non-regular operator monotone functions
DEFF Research Database (Denmark)
Gibilisco, P.; Hansen, Frank; Isola, T.
2009-01-01
We prove the existence of a bijection between the regular and the non-regular operator monotone functions satisfying a certain functional equation. As an application we give a new proof of the operator monotonicity of certain functions related to the Wigner-Yanase-Dyson skew information.......We prove the existence of a bijection between the regular and the non-regular operator monotone functions satisfying a certain functional equation. As an application we give a new proof of the operator monotonicity of certain functions related to the Wigner-Yanase-Dyson skew information....
Non-monotonic dynamics and crosstalk in signaling pathways and their implications for pharmacology
van Wijk, Roeland; Tans, Sander J.; Wolde, Pieter Rein Ten; Mashaghi, Alireza
2015-06-01
Currently, drug discovery approaches commonly assume a monotonic dose-response relationship. However, the assumption of monotonicity is increasingly being challenged. Here we show that for two simple interacting linear signaling pathways that carry two different signals with different physiological responses, a non-monotonic input-output relation can arise with simple network topologies including coherent and incoherent feed-forward loops. We show that non-monotonicity of the response functions has severe implications for pharmacological treatment. Fundamental constraints are imposed on the effectiveness and toxicity of any drug independent of its chemical nature and selectivity due to the specific network structure.
Institute of Scientific and Technical Information of China (English)
Igor Boglaev; Matthew Hardy
2008-01-01
This paper presents and analyzes a monotone domain decomposition algorithm for solving nonlinear singularly perturbed reaction-diffusion problems of parabolic type.To solve the nonlinear weighted average finite difference scheme for the partial differential equation,we construct a monotone domain decomposition algorithm based on a Schwarz alternating method and a box-domain decomposition.This algorithm needs only to solve linear discrete systems at each iterative step and converges monotonically to the exact solution of the nonlinear discrete problem. The rate of convergence of the monotone domain decomposition algorithm is estimated.Numerical experiments are presented.
The Knot Spectrum of Confined Random Equilateral Polygons
Directory of Open Access Journals (Sweden)
Diao Y.
2014-01-01
Full Text Available It is well known that genomic materials (long DNA chains of living organisms are often packed compactly under extreme confining conditions using macromolecular self-assembly processes but the general DNA packing mechanism remains an unsolved problem. It has been proposed that the topology of the packed DNA may be used to study the DNA packing mechanism. For example, in the case of (mutant bacteriophage P4, DNA molecules packed inside the bacteriophage head are considered to be circular since the two sticky ends of the DNA are close to each other. The DNAs extracted from the capsid without separating the two ends can thus preserve the topology of the (circular DNAs. It turns out that the circular DNAs extracted from bacteriophage P4 are non-trivially knotted with very high probability and with a bias toward chiral knots. In order to study this problem using a systematic approach based on mathematical modeling, one needs to introduce a DNA packing model under extreme volume confinement condition and test whether such a model can produce the kind of knot spectrum observed in the experiments. In this paper we introduce and study a model of equilateral random polygons con_ned in a sphere. This model is not meant to generate polygons that model DNA packed in a virus head directly. Instead, the average topological characteristics of this model may serve as benchmark data for totally randomly packed circular DNAs. The difference between the biologically observed topological characteristics and our benchmark data might reveal the bias of DNA packed in the viral capsids and possibly lead to a better understanding of the DNA packing mechanism, at least for the bacteriophage DNA. The purpose of this paper is to provide information about the knot spectrum of equilateral random polygons under such a spherical confinement with length and confinement ratios in a range comparable to circular DNAs packed inside bacteriophage heads.
Kerber, Laura; Dickson, James L.; Head, James W.; Grosfils, Eric B.
2017-01-01
Polygonal ridge networks, also known as boxwork or reticulate ridges, are found in numerous locations and geological contexts across Mars. Distinguishing the morphologies and geological context of the ridge networks sheds light on their potential as astrobiological and mineral resource sites of interest. The most widespread type of ridge morphology is characteristic of the Nili Fossae and Nilosyrtis region and consists of thin, criss-crossing ridges with a variety of heights, widths, and intersection angles. They are found in ancient Noachian terrains at a variety of altitudes (between -2500 and 2200 m) and geographic locations and are likely to be chemically altered fracture planes or mineral veins. They occur in the same general areas as valley networks and ancient lake basins, but they are not more numerous where these water-related features are concentrated, and can appear in places where th morphologies are absent. Similarly, some of the ridge networks are located near hydrated mineral detections, but there is not a one-to-one correlation. Smaller, light-toned ridges of variable widths have been found in Gale Crater and other rover sites and are interpreted to be smaller versions of the Nili-like ridges, mostly formed by the mineralization of fractures. This type of ridge is likely to be found in many other places on Mars as more high-resolution data become available. Sinus Meridiani contains many flat-topped ridges arranged into quasi-circular patterns. The ridges are eroding from a clay-rich unit, and could be formed by a similar process as the Nili-type ridges, but at a much larger scale and controlled by fractures made through a different process. Hellas Basin is host to a fourth type of ridge morphology consisting of large, thick, light-toned ridges forming regular polygons at several superimposed scales. While still enigmatic, these are most likely to be the result of sediment-filled fractures. The Eastern Medusae Fossae Formation contains large swaths
Polygonal triple (Kotz) osteotomy (over 10 years experience)
Sen, Cengiz; Gunes, Taner; Erdem, Mehmet; Ozger, Harzem; Tozun, I. Remzi
2006-01-01
We evaluated the results of polygonal triple (Kotz) osteotomy for the treatment of acetabular dysplasia over 10 years. This study included 31 hips of 27 patients who had the Kotz osteotomy for acetabular dysplasia. The mean age was 21.5 years. We performed the original Kotz osteotomy for the first 22 hips (group I), while the modified Kotz osteotomy through an intra-pelvic approach without damage to the abductor muscle was applied for the last 9 hips (group II). Patients were evaluated by cli...
A New Heuristic Constructing Minimal Steiner Trees inside Simple Polygons
Directory of Open Access Journals (Sweden)
Alireza Khosravinejad
2013-07-01
Full Text Available The Steiner tree problem has numerous applications in urban transportation network, design of electronic integrated circuits, and computer network routing. This problem aims at finding a minimum Steiner tree in the Euclidean space, the distance between each two edges of which has the least cost. This problem is considered as an NP-hard one. Assuming the simple polygon P with m vertices and n terminals, the purpose of the minimum Steiner tree in the Euclidean space is to connect the n terminals existing in p. In the proposed algorithm, obtaining optimal responses will be sought by turning this problem into the Steiner tree problem on a graph.
Giant polygons and mounds in the lowlands of Mars: signatures of an ancient ocean?
Oehler, Dorothy Z; Allen, Carlton C
2012-06-01
This paper presents the hypothesis that the well-known giant polygons and bright mounds of the martian lowlands may be related to a common process-a process of fluid expulsion that results from burial of fine-grained sediments beneath a body of water. Specifically, we hypothesize that giant polygons and mounds in Chryse and Acidalia Planitiae are analogous to kilometer-scale polygons and mud volcanoes in terrestrial, marine basins and that the co-occurrence of masses of these features in Chryse and Acidalia may be the signature of sedimentary processes in an ancient martian ocean. We base this hypothesis on recent data from both Earth and Mars. On Earth, 3-D seismic data illustrate kilometer-scale polygons that may be analogous to the giant polygons on Mars. The terrestrial polygons form in fine-grained sediments that have been deposited and buried in passive-margin, marine settings. These polygons are thought to result from compaction/dewatering, and they are commonly associated with fluid expulsion features, such as mud volcanoes. On Mars, in Chryse and Acidalia Planitiae, orbital data demonstrate that giant polygons and mounds have overlapping spatial distributions. There, each set of features occurs within a geological setting that is seemingly analogous to that of the terrestrial, kilometer-scale polygons (broad basin of deposition, predicted fine-grained sediments, and lack of significant horizontal stress). Regionally, the martian polygons and mounds both show a correlation to elevation, as if their formation were related to past water levels. Although these observations are based on older data with incomplete coverage, a similar correlation to elevation has been established in one local area studied in detail with newer higher-resolution data. Further mapping with the latest data sets should more clearly elucidate the relationship(s) of the polygons and mounds to elevation over the entire Chryse-Acidalia region and thereby provide more insight into this
Max-Sum Diversification, Monotone Submodular Functions and Dynamic Updates
Borodin, Allan; Ye, Yuli
2012-01-01
Result diversification has many important applications in databases, operations research, information retrieval, and finance. In this paper, we study and extend a particular version of result diversification, known as max-sum diversification. More specifically, we consider the setting where we are given a set of elements in a metric space and a set valuation function $f$ defined on every subset. For any given subset $S$, the overall objective is a linear combination of $f(S)$ and the sum of the distances induced by $S$. The goal is to find a subset $S$ satisfying some constraints that maximizes the overall objective. This problem is first studied by Gollapudi and Sharma for modular set functions and for sets satisfying a cardinality constraint. We consider an extension of the modular case to the monotone submodular case, for which the previous algorithm no longer applies. Interestingly, we are able to match the 2-approximation using a natural, but different greedy algorithm. We then further extend the problem...
Non-monotonicity of trace distance under tensor products
Energy Technology Data Exchange (ETDEWEB)
Maziero, Jonas, E-mail: jonas.maziero@ufsm.br [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Departamento de Fisica
2015-10-15
The trace distance (TD) possesses several of the good properties required for a faithful distance measure in the quantum state space. Despite its importance and ubiquitous use in quantum information science, one of its questionable features, its possible non-monotonicity under taking tensor products of its arguments (NMuTP), has been hitherto unexplored. In this article, we advance analytical and numerical investigations of this issue considering different classes of states living in a discrete and finite dimensional Hilbert space. Our results reveal that although this property of TD does not show up for pure states and for some particular classes of mixed states, it is present in a non-negligible fraction of the regarded density operators. Hence, even though the percentage of quartets of states leading to the NMuTP drawback of TD and its strength decrease as the system's dimension grows, this property of TD must be taken into account before using it as a figure of merit for distinguishing mixed quantum states. (author)
Dynamical zeta functions for piecewise monotone maps of the interval
Ruelle, David
2004-01-01
Consider a space M, a map f:M\\to M, and a function g:M \\to {\\mathbb C}. The formal power series \\zeta (z) = \\exp \\sum ^\\infty _{m=1} \\frac {z^m}{m} \\sum _{x \\in \\mathrm {Fix}\\,f^m} \\prod ^{m-1}_{k=0} g (f^kx) yields an example of a dynamical zeta function. Such functions have unexpected analytic properties and interesting relations to the theory of dynamical systems, statistical mechanics, and the spectral theory of certain operators (transfer operators). The first part of this monograph presents a general introduction to this subject. The second part is a detailed study of the zeta functions associated with piecewise monotone maps of the interval [0,1]. In particular, Ruelle gives a proof of a generalized form of the Baladi-Keller theorem relating the poles of \\zeta (z) and the eigenvalues of the transfer operator. He also proves a theorem expressing the largest eigenvalue of the transfer operator in terms of the ergodic properties of (M,f,g).
Completely Monotone Multisequences, Symmetric Probabilities and a Normal Limit Theorem
Indian Academy of Sciences (India)
J C Gupta
2000-11-01
Let G, be the set of all partial completely monotone multisequences of order and degree , i.e., multisequences (1, 2,$\\ldots$ ,k), 1, 2,$\\ldots$ , = 0, 1, 2,$\\ldots$ ,1 + 2 + \\$cdots$ + ≤ n, (0,0,$\\ldots$ ,0) = 1 and $(-1)^{_0}^{_0}$ (1, 2,$\\ldots$ ,)≥ 0 whenever 0 ≤ -(1 + 2 +$\\cdots$ +) where (1, 2,$\\ldots$ ,)=(1+1, 2,$\\ldots$ ,)+ (1,2+1,$\\ldots$ ,)+$\\cdots$ + (1, 2,$\\ldots$ ,+1)-(1,2,$\\ldots$ ,)$. Further, let $\\prod_{n,k}$ be the set of all symmetric probabilities on ${0, 1, 2,\\ldots ,k}^{n}$. We establish a one-to-one correspondence between the sets G, and $\\prod_{n, k}$ and use it to formulate and answer interesting questions about both. Assigning to G, the uniform probability measure, we show that, as → ∞ , any fixed section {(1, 2,$\\ldots$ ,), 1 ≤ $\\sum ≤ }, properly centered and normalized, is asymptotically multivariate normal. That is, $\\left\\{\\sqrt{\\left(\\binom{n+k}{k}\\right)}((1, 2,\\ldots ,)-c_0(1, 2,\\ldots ,), 1≤ _1+2+\\cdots +_k≤ m\\right\\}$ converges weakly to MVN[0,]; the centering constants 0(1, 2,$\\ldots$ ,) and the asymptotic covariances depend on the moments of the Dirichlet $(1, 1,\\ldots ,1; 1)$ distribution on the standard simplex in .
Corso, Francesco Dal; Bigoni, Davide
2016-01-01
An infinite class of nonuniform antiplane shear fields is considered for a linear elastic isotropic space and (non-intersecting) isotoxal star-shaped polygonal voids and rigid inclusions perturbing these fields are solved. Through the use of the complex potential technique together with the generalized binomial and the multinomial theorems, full-field closed-form solutions are obtained in the conformal plane. The particular (and important) cases of star-shaped cracks and rigid-line inclusions (stiffeners) are also derived. Except for special cases (addressed in Part II), the obtained solutions show singularities at the inclusion corners and at the crack and stiffener ends, where the stress blows-up to infinity, and is therefore detrimental to strength. It is for this reason that the closed-form determination of the stress field near a sharp inclusion or void is crucial for the design of ultra-resistant composites.
Origami tubes with reconfigurable polygonal cross-sections.
Filipov, E T; Paulino, G H; Tachi, T
2016-01-01
Thin sheets can be assembled into origami tubes to create a variety of deployable, reconfigurable and mechanistically unique three-dimensional structures. We introduce and explore origami tubes with polygonal, translational symmetric cross-sections that can reconfigure into numerous geometries. The tubular structures satisfy the mathematical definitions for flat and rigid foldability, meaning that they can fully unfold from a flattened state with deformations occurring only at the fold lines. The tubes do not need to be straight and can be constructed to follow a non-linear curved line when deployed. The cross-section and kinematics of the tubular structures can be reprogrammed by changing the direction of folding at some folds. We discuss the variety of tubular structures that can be conceived and we show limitations that govern the geometric design. We quantify the global stiffness of the origami tubes through eigenvalue and structural analyses and highlight the mechanical characteristics of these systems. The two-scale nature of this work indicates that, from a local viewpoint, the cross-sections of the polygonal tubes are reconfigurable while, from a global viewpoint, deployable tubes of desired shapes are achieved. This class of tubes has potential applications ranging from pipes and micro-robotics to deployable architecture in buildings.
Transit Traffic Analysis Zone Delineating Method Based on Thiessen Polygon
Directory of Open Access Journals (Sweden)
Shuwei Wang
2014-04-01
Full Text Available A green transportation system composed of transit, busses and bicycles could be a significant in alleviating traffic congestion. However, the inaccuracy of current transit ridership forecasting methods is imposing a negative impact on the development of urban transit systems. Traffic Analysis Zone (TAZ delineating is a fundamental and essential step in ridership forecasting, existing delineating method in four-step models have some problems in reflecting the travel characteristics of urban transit. This paper aims to come up with a Transit Traffic Analysis Zone delineation method as supplement of traditional TAZs in transit service analysis. The deficiencies of current TAZ delineating methods were analyzed, and the requirements of Transit Traffic Analysis Zone (TTAZ were summarized. Considering these requirements, Thiessen Polygon was introduced into TTAZ delineating. In order to validate its feasibility, Beijing was then taken as an example to delineate TTAZs, followed by a spatial analysis of office buildings within a TTAZ and transit station departure passengers. Analysis result shows that the TTAZs based on Thiessen polygon could reflect the transit travel characteristic and is of in-depth research value.
The global convergence of the non-quasi-Newton methods with non-monotone line search
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The non-quasi-Newton methods for unconstrained optimization was investigated. Non-monotone line search procedure is introduced, which is combined with the non-quasi-Newton family. Under the uniform convexity assumption on objective function, the global convergence of the non-quasi-Newton family was proved.Numerical experiments showed that the non-monotone line search was more effective.
How to project onto the monotone nonnegative cone using Pool Adjacent Violators type algorithms
Németh, A B
2012-01-01
The metric projection onto an order nonnegative cone from the metric projection onto the corresponding order cone is derived. Particularly, we can use Pool Adjacent Violators-type algorithms developed for projecting onto the monotone cone for projecting onto the monotone nonnegative cone too.
An analysis of the stability and monotonicity of a kind of control models
Directory of Open Access Journals (Sweden)
LU Yifa
2013-06-01
Full Text Available The stability and monotonicity of control systems with parameters are considered.By the iterative relationship of the coefficients of characteristic polynomials and the Mathematica software,some sufficient conditions for the monotonicity and stability of systems are given.
Tijs, S.H.; Moretti, S.; Brânzei, R.; Norde, H.W.
2005-01-01
A new way is presented to define for minimum cost spanning tree (mcst-) games the irreducible core, which is introduced by Bird in 1976.The Bird core correspondence turns out to have interesting monotonicity and additivity properties and each stable cost monotonic allocation rule for mcst-problems i
Effects of temperature on monotonic and fatigue properties of carbon fibre epoxy cross ply laminates
Matsuhisa, Y.; King, J.
1993-01-01
The effects of test temperature on damage accumulation behaviour has been studied using "Torayca" T800H / #3631 in conditions of monotonic and fatigue loading. The damage accumulation behaviour was found to vary as a function of the test temperature, with the effect of temperature on the damage behaviour being different between monotonic and fatigue loading.
Effects of temperature on monotonic and fatigue properties of carbon fibre epoxy cross ply laminates
Energy Technology Data Exchange (ETDEWEB)
Matsuhisa, Y. (Composite Materials Research Labs., Toray Industries Inc., Ehime (Japan)); King, J.E. (Composite Materials Research Labs., Toray Industries Inc., Ehime (Japan) Dept. of Materials Science and Metallurgy, Univ. of Cambridge (United Kingdom))
1993-11-01
The effects of test temperature on damage accumulation behaviour has been studied using ''Torayca'' T800H/[3631] in conditions of monotonic and fatigue loading. The damage accumulation behaviour was found to vary as a function of the test temperature, with the effect of temperature on the damage behaviour being different between monotonic and fatigue loading. (orig.).
Tijs, S.H.; Moretti, S.; Brânzei, R.; Norde, H.W.
2005-01-01
A new way is presented to define for minimum cost spanning tree (mcst-) games the irreducible core, which is introduced by Bird in 1976.The Bird core correspondence turns out to have interesting monotonicity and additivity properties and each stable cost monotonic allocation rule for mcst-problems
Kovyrkina, O. A.; Ostapenko, V. V.
2016-05-01
The monotonicity of the CABARET scheme approximating a hyperbolic differential equation with a sign-changing characteristic field is analyzed. Monotonicity conditions for this scheme are obtained in domains where the characteristics have a sign-definite propagation velocity and near sonic lines, on which the propagation velocity changes its sign. These properties of the CABARET scheme are illustrated by test computations.
Tijs, S.H.; Moretti, S.; Brânzei, R.; Norde, H.W.
2005-01-01
A new way is presented to define for minimum cost spanning tree (mcst-) games the irreducible core, which is introduced by Bird in 1976.The Bird core correspondence turns out to have interesting monotonicity and additivity properties and each stable cost monotonic allocation rule for mcst-problems i
Computation of displacements for nonlinear elastic beam models using monotone iterations
Directory of Open Access Journals (Sweden)
Philip Korman
1988-01-01
Full Text Available We study displacement of a uniform elastic beam subject to various physically important boundary conditions. Using monotone methods, we discuss stability and instability of solutions. We present computations, which suggest efficiency of monotone methods for fourth order boundary value problems.
Aerial target recognition using MRA, GVF snakes, and polygon approximation
Lu, Zhen Z.; Zhang, Taiyi; Xu, Jian
2003-04-01
The traditional method to extract target contour from aerial target image is changing the aerial image into a gray level image with multiple thresholds or binary image with single threshold. From the edge of target, contour can be extracted according to the changed value. The traditional method is useful only when contrast between target and background is in the proper degree. Snakes are curves defined within an image domain that can move under the influence of internal force coming from within the curve itself and external forces are defined so that the snake will conform to an object boundary or other desired features within an image. Snakes have been proved an effective method and widely used in image processing and computer vision. Snakes synthesize parametric curves within an image domain and allow them to move toward desired edges. Particular advantages of the GVF(Gradient Vector Flow) snakes over a traditional snakes are its insensitivity to initialization and its ability to move into boundary concavities. Its initializations can be inside, outside, or across the object"s boundary. The GVF snake does not need prior knowledge about whether to shrink or expand toward the boundary. This increased capture range is achieved through a diffusion process that does not blur the edges of themselves. Affected by the light from different incident angle, the brightness of aerial target surface changed greatly in a complicate mode. So the GVF snakes is not fast, accurate and effective all the time for this kind of images. A new contour extracting method, GVF Snakes Combined with wavelet multi-resolution Analysis is proposed in this paper. In this algorithm, bubble wavelet is used iteratively to do the multi resolution analysis in the order of degressive scale before GVF Snakes is used every time to extract accurate contour of target. After accurate contour is extracted, polygon approximation is used to extract characteristics to realize the recognition of aerial target
KiMPA: A Kinematics-Based Method for Polygon Approximation
Yakhno, T.M.; Saykol, E.; Gülesir, G.; Gudukbay, U.; Ulusoy, Ö.
2002-01-01
In different types of information systems, such as multimedia information systems and geographic information systems, object-based information is represented via polygons corresponding to the boundaries of object regions. In many applications, the polygons have large number of vertices and edges,
Hierarchical vertical decompositions, ray shooting, and circular arc queries in simple polygons
Oostrum, R. van; Ahn, Hee-Kap; Cheng, S.-W.; Golin, Mordecai
1999-01-01
A new hierarchical decomposition of a simple polygon is introduced. The hierarchy has depth O(log n), linear size, and its regions have maximum degree three. Using this hierarchy, circular ray shooting queries in a simple polygon can be answered in O(log* n) query time and O(nlogn) space. If the rad
On the Computation of the Moments of a Polygon, with some Applications
Soerjadi, R.
1968-01-01
A general formula for moments of a polygon is derived. The concept of 'moment' is a generalization of the statical, inertial and centrifugal moment respectively of a polygon, which as such are special moments of first and second order. Moments of higher order, however, also have applications in engi
A numerical investigation of sub-wavelength resonances in polygonal metamaterial cylinders
DEFF Research Database (Denmark)
Arslanagic, Samel; Breinbjerg, Olav
2009-01-01
of polygonal cylinders excited by a nearby electric line current is analyzed numerically and it is shown, through detailed analysis of the near-field distribution and radiation resistance, that these polygonal cylinders do indeed support sub-wavelength resonances similar to those of the circular cylinders...
Intersection Logic in sequent calculus style
Della Rocca, Simona Ronchi; Stavrinos, Yiorgos; Veneti, Anastasia; 10.4204/EPTCS.45.2
2011-01-01
The intersection type assignment system has been designed directly as deductive system for assigning formulae of the implicative and conjunctive fragment of the intuitionistic logic to terms of lambda-calculus. But its relation with the logic is not standard. Between all the logics that have been proposed as its foundation, we consider ISL, which gives a logical interpretation of the intersection by splitting the intuitionistic conjunction into two connectives, with a local and global behaviour respectively, being the intersection the local one. We think ISL is a logic interesting by itself, and in order to support this claim we give a sequent calculus formulation of it, and we prove that it enjoys the cut elimination property.
Modeling aggressive driver behavior at unsignalized intersections.
Kaysi, Isam A; Abbany, Ali S
2007-07-01
The processing of vehicles at unsignalized intersections is a complex and highly interactive process, whereby each driver makes individual decisions about when, where, and how to complete the required maneuver, subject to his perceptions of distances, velocities, and own car's performance. Typically, the performance of priority-unsignalized intersections has been modeled with probabilistic approaches that consider the distribution of gaps in the major-traffic stream and their acceptance by the drivers of minor street vehicles based on the driver's "critical gap". This paper investigates the aggressive behavior of minor street vehicles at intersections that are priority-unsignalized but operate with little respect of control measures. The objective is to formulate a behavioral model that predicts the probability that a driver performs an aggressive maneuver as a function of a set of driver and traffic attributes. Parameters that were tested and modeled include driver characteristics (gender and age), car characteristics (performance and model year), and traffic attributes (number of rejected gaps, total waiting time at head of queue, and major-traffic speed). Binary probit models are developed and tested, based on a collected data set from an unsignalized intersection in the city of Beirut, to determine which of the studied variables are statistically significant in determining the aggressiveness of a specific driver. Primary conclusions reveal that age, car performance, and average speed on the major road are the major determinants of aggressive behavior. Another striking conclusion is that the total waiting time of the driver while waiting for an acceptable gap is of little significance in incurring the "forcing" behavior. The obtained model is incorporated in a simple simulation framework that reflects driver behavior and traffic stream interactions in estimating delay and conflict measures at unsignalized intersections. The simulation results were then compared
Simulation of intersecting black brane solutions
Ivashchuk, V D; Selivanov, A B
2003-01-01
A family of spherically symmetric solutions with horizon in the model with multi-component anisotropic fluid (MCAF) is obtained. The metric of any solution contains n-1 Ricci-flat ``internal space'' metrics and for certain equations of state (p_i = \\pm \\rho) coincides with the metric of intersecting black brane solution in the model with antisymmetric forms. Examples of simulation of intersecting M2 and M5 black branes are considered. The post-Newtonian parameters beta and gamma corresponding to the 4-dimensional section of the metric are calculated.
Switching exciton pulses through conical intersections
Leonhardt, K; Rost, J -M
2013-01-01
Exciton pulses transport excitation and entanglement adiabatically through Rydberg aggregates, assemblies of highly excited light atoms, which are set into directed motion by resonant dipole-dipole interaction. Here, we demonstrate the coherent splitting of such pulses as well as the spatial segregation of electronic excitation and atomic motion. Both mechanisms exploit local non-adiabatic effects at a conical intersection, turning them from a decoherence source into an asset. The intersection provides a sensitive knob controlling the propagation direction and coherence properties of exciton pulses.
Probabilistic Analysis of Pattern Formation in Monotonic Self-Assembly.
Moore, Tyler G; Garzon, Max H; Deaton, Russell J
2015-01-01
Inspired by biological systems, self-assembly aims to construct complex structures. It functions through piece-wise, local interactions among component parts and has the potential to produce novel materials and devices at the nanoscale. Algorithmic self-assembly models the product of self-assembly as the output of some computational process, and attempts to control the process of assembly algorithmically. Though providing fundamental insights, these computational models have yet to fully account for the randomness that is inherent in experimental realizations, which tend to be based on trial and error methods. In order to develop a method of analysis that addresses experimental parameters, such as error and yield, this work focuses on the capability of assembly systems to produce a pre-determined set of target patterns, either accurately or perhaps only approximately. Self-assembly systems that assemble patterns that are similar to the targets in a significant percentage are "strong" assemblers. In addition, assemblers should predominantly produce target patterns, with a small percentage of errors or junk. These definitions approximate notions of yield and purity in chemistry and manufacturing. By combining these definitions, a criterion for efficient assembly is developed that can be used to compare the ability of different assembly systems to produce a given target set. Efficiency is a composite measure of the accuracy and purity of an assembler. Typical examples in algorithmic assembly are assessed in the context of these metrics. In addition to validating the method, they also provide some insight that might be used to guide experimentation. Finally, some general results are established that, for efficient assembly, imply that every target pattern is guaranteed to be assembled with a minimum common positive probability, regardless of its size, and that a trichotomy exists to characterize the global behavior of typical efficient, monotonic self-assembly systems
Probabilistic Analysis of Pattern Formation in Monotonic Self-Assembly.
Directory of Open Access Journals (Sweden)
Tyler G Moore
Full Text Available Inspired by biological systems, self-assembly aims to construct complex structures. It functions through piece-wise, local interactions among component parts and has the potential to produce novel materials and devices at the nanoscale. Algorithmic self-assembly models the product of self-assembly as the output of some computational process, and attempts to control the process of assembly algorithmically. Though providing fundamental insights, these computational models have yet to fully account for the randomness that is inherent in experimental realizations, which tend to be based on trial and error methods. In order to develop a method of analysis that addresses experimental parameters, such as error and yield, this work focuses on the capability of assembly systems to produce a pre-determined set of target patterns, either accurately or perhaps only approximately. Self-assembly systems that assemble patterns that are similar to the targets in a significant percentage are "strong" assemblers. In addition, assemblers should predominantly produce target patterns, with a small percentage of errors or junk. These definitions approximate notions of yield and purity in chemistry and manufacturing. By combining these definitions, a criterion for efficient assembly is developed that can be used to compare the ability of different assembly systems to produce a given target set. Efficiency is a composite measure of the accuracy and purity of an assembler. Typical examples in algorithmic assembly are assessed in the context of these metrics. In addition to validating the method, they also provide some insight that might be used to guide experimentation. Finally, some general results are established that, for efficient assembly, imply that every target pattern is guaranteed to be assembled with a minimum common positive probability, regardless of its size, and that a trichotomy exists to characterize the global behavior of typical efficient, monotonic
Fused Lasso Screening Rules via the Monotonicity of Subdifferentials.
Wang, Jie; Fan, Wei; Ye, Jieping
2015-09-01
Fused Lasso is a popular regression technique that encodes the smoothness of the data. It has been applied successfully to many applications with a smooth feature structure. However, the computational cost of the existing solvers for fused Lasso is prohibitive when the feature dimension is extremely large. In this paper, we propose novel screening rules that are able to quickly identity the adjacent features with the same coefficients. As a result, the number of variables to be estimated can be significantly reduced, leading to substantial savings in computational cost and memory usage. To the best of our knowledge, the proposed approach is the first attempt to develop screening methods for the fused Lasso problem with general data matrix. Our major contributions are: 1) we derive a new dual formulation of fused Lasso that comes with several desirable properties; 2) we show that the new dual formulation of fused Lasso is equivalent to that of the standard Lasso by two affine transformations; 3) we propose a novel framework for developing effective and efficient screening rules for fused Lasso via the monotonicity of the subdifferentials (FLAMS). Some appealing features of FLAMS are: 1) our methods are safe in the sense that the detected adjacent features are guaranteed to have the same coefficients; 2) the dataset needs to be scanned only once to run the screening, whose computational cost is negligible compared to that of solving the fused Lasso; (3) FLAMS is independent of the solvers and can be integrated with any existing solvers. We have evaluated the proposed FLAMS rules on both synthetic and real datasets. The experiments indicate that FLAMS is very effective in identifying the adjacent features with the same coefficients. The speedup gained by FLAMS can be orders of magnitude.
Local Monotonicity and Isoperimetric Inequality on Hypersurfaces in Carnot groups
Directory of Open Access Journals (Sweden)
Francesco Paolo Montefalcone
2010-12-01
Full Text Available Let G be a k-step Carnot group of homogeneous dimension Q. Later on we shall present some of the results recently obtained in [32] and, in particular, an intrinsic isoperimetric inequality for a C2-smooth compact hypersurface S with boundary @S. We stress that S and @S are endowed with the homogeneous measures n????1 H and n????2 H , respectively, which are actually equivalent to the intrinsic (Q - 1-dimensional and (Q - 2-dimensional Hausdor measures with respect to a given homogeneous metric % on G. This result generalizes a classical inequality, involving the mean curvature of the hypersurface, proven by Michael and Simon [29] and Allard [1], independently. One may also deduce some related Sobolev-type inequalities. The strategy of the proof is inspired by the classical one and will be discussed at the rst section. After reminding some preliminary notions about Carnot groups, we shall begin by proving a linear isoperimetric inequality. The second step is a local monotonicity formula. Then we may achieve the proof by a covering argument.We stress however that there are many dierences, due to our non-Euclidean setting.Some of the tools developed ad hoc are, in order, a \\blow-up" theorem, which holds true also for characteristic points, and a smooth Coarea Formula for the HS-gradient. Other tools are the horizontal integration by parts formula and the 1st variation formula for the H-perimeter n????1H already developed in [30, 31] and then generalized to hypersurfaces having non-empty characteristic set in [32]. These results can be useful in the study of minimal and constant horizontal mean curvature hypersurfaces in Carnot groups.
The average inter-crossing number of equilateral random walks and polygons
Diao, Y.; Dobay, A.; Stasiak, A.
2005-09-01
In this paper, we study the average inter-crossing number between two random walks and two random polygons in the three-dimensional space. The random walks and polygons in this paper are the so-called equilateral random walks and polygons in which each segment of the walk or polygon is of unit length. We show that the mean average inter-crossing number ICN between two equilateral random walks of the same length n is approximately linear in terms of n and we were able to determine the prefactor of the linear term, which is a=\\frac{3\\ln 2}{8}\\approx 0.2599 . In the case of two random polygons of length n, the mean average inter-crossing number ICN is also linear, but the prefactor of the linear term is different from that of the random walks. These approximations apply when the starting points of the random walks and polygons are of a distance ρ apart and ρ is small compared to n. We propose a fitting model that would capture the theoretical asymptotic behaviour of the mean average ICN for large values of ρ. Our simulation result shows that the model in fact works very well for the entire range of ρ. We also study the mean ICN between two equilateral random walks and polygons of different lengths. An interesting result is that even if one random walk (polygon) has a fixed length, the mean average ICN between the two random walks (polygons) would still approach infinity if the length of the other random walk (polygon) approached infinity. The data provided by our simulations match our theoretical predictions very well.
Deformations of polyhedra and polygons by the unitary group
Livine, Etera R.
2013-12-01
We introduce the set of framed (convex) polyhedra with N faces as the symplectic quotient {{C}}^{2N}//SU(2). A framed polyhedron is then parametrized by N spinors living in {{C}}2 satisfying suitable closure constraints and defines a usual convex polyhedron plus extra U(1) phases attached to each face. We show that there is a natural action of the unitary group U(N) on this phase space, which changes the shape of faces and allows to map any (framed) polyhedron onto any other with the same total (boundary) area. This identifies the space of framed polyhedra to the Grassmannian space U(N)/ (SU(2)×U(N-2)). We show how to write averages of geometrical observables (polynomials in the faces' area and the angles between them) over the ensemble of polyhedra (distributed uniformly with respect to the Haar measure on U(N)) as polynomial integrals over the unitary group and we provide a few methods to compute these integrals systematically. We also use the Itzykson-Zuber formula from matrix models as the generating function for these averages and correlations. In the quantum case, a canonical quantization of the framed polyhedron phase space leads to the Hilbert space of SU(2) intertwiners (or, in other words, SU(2)-invariant states in tensor products of irreducible representations). The total boundary area as well as the individual face areas are quantized as half-integers (spins), and the Hilbert spaces for fixed total area form irreducible representations of U(N). We define semi-classical coherent intertwiner states peaked on classical framed polyhedra and transforming consistently under U(N) transformations. And we show how the U(N) character formula for unitary transformations is to be considered as an extension of the Itzykson-Zuber to the quantum level and generates the traces of all polynomial observables over the Hilbert space of intertwiners. We finally apply the same formalism to two dimensions and show that classical (convex) polygons can be described in a
A formula for crossing probabilities of critical systems inside polygons
Flores, S. M.; Simmons, J. J. H.; Kleban, P.; Ziff, R. M.
2017-02-01
In this article, we use our results from Flores and Kleban (2015 Commun. Math. Phys. 333 389-434, 2015 Commun. Math. Phys. 333 435-81, 2015 Commun. Math. Phys. 333 597-667, 2015 Commun. Math. Phys. 333 669-715) to generalize known formulas for crossing probabilities. Prior crossing results date back to Cardy’s prediction of a formula for the probability that a percolation cluster in two dimensions connects the left and right sides of a rectangle at the percolation critical point in the continuum limit (Cardy 1992 J. Phys. A: Math. Gen. 25 L201-6). Here, we predict a new formula for crossing probabilities of a continuum limit loop-gas model on a planar lattice inside a 2N-sided polygon. In this model, boundary loops exit and then re-enter the polygon through its vertices, with exactly one loop passing once through each vertex, and these loops join the vertices pairwise in some specified connectivity through the polygon’s exterior. The boundary loops also connect the vertices through the interior, which we regard as a crossing event. For particular values of the loop fugacity, this formula specializes to FK cluster (resp. spin cluster) crossing probabilities of a critical Q-state random cluster (resp. Potts) model on a lattice inside the polygon in the continuum limit. This includes critical percolation as the Q = 1 random cluster model. These latter crossing probabilities are conditioned on a particular side-alternating free/fixed (resp. fluctuating/fixed) boundary condition on the polygon’s perimeter, related to how the boundary loops join the polygon’s vertices pairwise through the polygon’s exterior in the associated loop-gas model. For Q\\in ≤ft\\{2,3,4\\right\\} , we compare our predictions of these random cluster (resp. Potts) model crossing probabilities in a rectangle (N = 2) and in a hexagon (N = 3) with high-precision computer simulation measurements. We find that the measurements agree with our predictions very
Energy Technology Data Exchange (ETDEWEB)
Coe, Joshua D [Los Alamos National Laboratory; Levine, B G [U IL AT URBANA-CHAMPAIGN; Ong, M T [UIUC; Martinez, T J [UIUC
2008-01-01
We discuss the connectivity of intersection spaces and the role of minimal energy points within these intersection spaces (minimal energy conical intersections or MECIs) in promoting nonadiabatic transitions. We focus on malonaldeyde as a specific example, where there is a low-lying three-state conical intersection. This three-state intersection is the global minimum on the bright excited electronic state, but it plays a limited role in population transfer in our ab initio multiple spawning (AIMS) simulations because the molecule must traverse a series of two-state conical intersections to reach the three-state intersection. Due to the differences in seam space dimensionality separating conventional (two-state) and three-state intersections, we suggest that dynamical effects arising directly from a three-state intersection may prove difficult to observe in general. We also use a newly developed method for intersection optimization with geometric constraints to demonstrate the connectivity of all the stationary points in the intersection spaces for malonaldehyde. This supports the conjecture that all intersection spaces are connected, and that three-state intersections play a key role in extending this connectivity to all pairs of states, e.g. the S{sub 1}/S{sub 0} and S{sub 2}/S{sub 1} intersection spaces.
Energy Technology Data Exchange (ETDEWEB)
Angelis, G I; Kotasidis, F A; Matthews, J C [Imaging, Proteomics and Genomics, MAHSC, University of Manchester, Wolfson Molecular Imaging Centre, Manchester (United Kingdom); Reader, A J [Montreal Neurological Institute, McGill University, Montreal (Canada); Lionheart, W R, E-mail: georgios.angelis@mmic.man.ac.uk [School of Mathematics, University of Manchester, Alan Turing Building, Manchester (United Kingdom)
2011-07-07
Iterative expectation maximization (EM) techniques have been extensively used to solve maximum likelihood (ML) problems in positron emission tomography (PET) image reconstruction. Although EM methods offer a robust approach to solving ML problems, they usually suffer from slow convergence rates. The ordered subsets EM (OSEM) algorithm provides significant improvements in the convergence rate, but it can cycle between estimates converging towards the ML solution of each subset. In contrast, gradient-based methods, such as the recently proposed non-monotonic maximum likelihood (NMML) and the more established preconditioned conjugate gradient (PCG), offer a globally convergent, yet equally fast, alternative to OSEM. Reported results showed that NMML provides faster convergence compared to OSEM; however, it has never been compared to other fast gradient-based methods, like PCG. Therefore, in this work we evaluate the performance of two gradient-based methods (NMML and PCG) and investigate their potential as an alternative to the fast and widely used OSEM. All algorithms were evaluated using 2D simulations, as well as a single [{sup 11}C]DASB clinical brain dataset. Results on simulated 2D data show that both PCG and NMML achieve orders of magnitude faster convergence to the ML solution compared to MLEM and exhibit comparable performance to OSEM. Equally fast performance is observed between OSEM and PCG for clinical 3D data, but NMML seems to perform poorly. However, with the addition of a preconditioner term to the gradient direction, the convergence behaviour of NMML can be substantially improved. Although PCG is a fast convergent algorithm, the use of a (bent) line search increases the complexity of the implementation, as well as the computational time involved per iteration. Contrary to previous reports, NMML offers no clear advantage over OSEM or PCG, for noisy PET data. Therefore, we conclude that there is little evidence to replace OSEM as the algorithm of choice
Numerical aspects of spectral segmentation on polygonal grids
Energy Technology Data Exchange (ETDEWEB)
Matsekh, Anna [Los Alamos National Laboratory; Skurikhin, Alexei [Los Alamos National Laboratory; Prasad, Lakshman [Los Alamos National Laboratory; Rosten, Edward [UNIV OF CAMBRIDGE
2010-01-01
The authors analyze numerical behavior of the spectral graph partitioning problem arising in the Normalized Cuts formulation of the image segmentation problem on polygonal grids. They make an observation that in the presence of rounding errors the eigenvector corresponding to the k-th smallest eigenvalue of the generalized graph Laplacian should contain more than k nodal domains that represent coherent segments in the image. As the result, the eigenvector corresponding to the trivial solution carries a wealth of information about the nodal domains in the image and can be used as an initial guess for the Krylov subspace eigensolver, while the computed eigenvector subspace, corresponding to just a few of the lowest eigenvalues of the graph Laplacian, will contain sufficient information for obtaining meaningful segmentation.
Optimal placement of convex polygons to maximize point containment
Energy Technology Data Exchange (ETDEWEB)
Dickerson, M. [Middlebury College, VT (United States); Scharstein, D. [Cornell Univ., Ithaca, NY (United States)
1996-12-31
Given a convex polygon P with m vertices and a set S of n points in the plane, we consider the problem of finding a placement of P that contains the maximum number of points in S. We allow both translation and rotation. Our algorithm is self-contained and utilizes the geometric properties of the containing regions in the parameter space of transformations. The algorithm requires O(nk{sup 2} m{sup 2} log(mk)) time and O(n + m) space, where k is the maximum number of points contained. This provides a linear improvement over the best previously known algorithm when k is large ({Theta}(n)) and a cubic improvement when k is small. We also show that the algorithm can be extended to solve bichromatic and general weighted variants of the problem.
Polygonal triple (Kotz) osteotomy (over 10 years experience).
Sen, Cengiz; Gunes, Taner; Erdem, Mehmet; Ozger, Harzem; Tozun, I Remzi
2007-06-01
We evaluated the results of polygonal triple (Kotz) osteotomy for the treatment of acetabular dysplasia over 10 years. This study included 31 hips of 27 patients who had the Kotz osteotomy for acetabular dysplasia. The mean age was 21.5 years. We performed the original Kotz osteotomy for the first 22 hips (group I), while the modified Kotz osteotomy through an intra-pelvic approach without damage to the abductor muscle was applied for the last 9 hips (group II). Patients were evaluated by clinically and radiologically. The average follow-up was 106 months in group I, and 18 months in group II. The Trendelenburg gait was unchanged for four patients in group I and for one patient in group II. The Harris Hip Score improved in all patients postoperatively. Radiographic assesment showed improvement in both groups in terms of the angle of CE, VCE, and Sharp postoperatively(PTrendelenburg gait compared to the original Kotz osteotomy.
A Facile Method for Synthesis of Polygonal Silver Nanopartilces
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The synthesis of nanosized powders and their assembly is of considerable importance to the microelectronics industry because of the pervasive drive to miniaturize components. In this work, silver (Ag) nanoparticls was syntheized. Polygonal silver nanoparticls were synthesized by reacting AgNO3 with hydroquinone, in the presence of poly-(vinylpyrrolidone) (PVP) and an ionic liquid 1-n-butyl-3-methylimidazolium hexafluoroborate ([BMIM]·PF6) at ambient temperature. XRD shows that the crystal structure of the nanoparticles is face-centered cubic. TEM measurements display the silver particles with uniform size and narrow particle size distributions. The UV-Vis spectra of the nanoplates distinguish from those of the samples prepared in the absence of PVP and/or ILs. This method is facile and the as-prepared silver nanoparticls are also stable in some solvents, such as ethanol and water.
Reachability by paths of bounded curvature in a convex polygon
Ahn, Heekap
2012-01-01
Let B be a point robot moving in the plane, whose path is constrained to forward motions with curvature at most 1, and let P be a convex polygon with n vertices. Given a starting configuration (a location and a direction of travel) for B inside P, we characterize the region of all points of P that can be reached by B, and show that it has complexity O(n). We give an O(n2) time algorithm to compute this region. We show that a point is reachable only if it can be reached by a path of type CCSCS, where C denotes a unit circle arc and S denotes a line segment. © 2011 Elsevier B.V.
Treks into intuitive geometry the world of polygons and polyhedra
Akiyama, Jin
2015-01-01
This book is written in a style that uncovers the mathematical theories buried in our everyday lives such as examples from patterns that appear in nature, art, and traditional crafts, and in mathematical mechanisms in techniques used by architects. The authors believe that through dialogues between students and mathematicians, readers may discover the processes by which the founders of the theories came to their various conclusions―their trials, errors, tribulations, and triumphs. The goal is for readers to refine their mathematical sense of how to find good questions and how to grapple with these problems. Another aim is to provide enjoyment in the process of applying mathematical rules to beautiful art and design by examples that highlight the wonders and mysteries from our daily lives. To fulfill these aims, this book deals with the latest unique and beautiful results in polygons and polyhedra and the dynamism of geometrical research history that can be found around us. The term "intuitive geometry" was ...
Convergence of Wachspress coordinates: from polygons to curved domains
Kosinka, Jiří
2014-08-08
Given a smooth, strictly convex planar domain, we investigate point-wise convergence of the sequence of Wachspress coordinates defined over finer and finer inscribed polygonal approximations of the domain. Based on a relation between the discrete Wachspress case and the limit smooth case given by the Wachspress kernel defined by Warren et al., we show that the corresponding sequences of Wachspress interpolants and mappings converge as 𝓞(h2) for a sampling step size h of the boundary curve of the domain as h → 0. Several examples are shown to numerically validate the results and to visualise the behaviour of discrete interpolants and mappings as they converge to their smooth counterparts. Empirically, the same convergence order is observed also for mean value coordinates. Moreover, our numerical tests suggest that the convergence of interpolants and mappings is uniform both in the Wachspress and mean value cases. © 2014 Springer Science+Business Media New York.
Quadratic Serendipity Finite Elements on Polygons Using Generalized Barycentric Coordinates
Rand, Alexander; Bajaj, Chandrajit
2011-01-01
We introduce a finite element construction for use on the class of convex, planar polygons and show it obtains a quadratic error convergence estimate. On a convex n-gon satisfying simple geometric criteria, our construction produces 2n basis functions, associated in a Lagrange-like fashion to each vertex and each edge midpoint, by transforming and combining a set of n(n+1)/2 basis functions known to obtain quadratic convergence. The technique broadens the scope of the so-called `serendipity' elements, previously studied only for quadrilateral and regular hexahedral meshes, by employing the theory of generalized barycentric coordinates. Numerical evidence is provided on a trapezoidal quadrilateral mesh, previously not amenable to serendipity constructions, and applications to adaptive meshing are discussed.
Occurrence of normal and anomalous diffusion in polygonal billiard channels.
Sanders, David P; Larralde, Hernán
2006-02-01
From extensive numerical simulations, we find that periodic polygonal billiard channels with angles which are irrational multiples of pi generically exhibit normal diffusion (linear growth of the mean squared displacement) when they have a finite horizon, i.e., when no particle can travel arbitrarily far without colliding. For the infinite horizon case we present numerical tests showing that the mean squared displacement instead grows asymptotically as t ln t. When the unit cell contains accessible parallel scatterers, however, we always find anomalous super-diffusion, i.e., power-law growth with an exponent larger than . This behavior cannot be accounted for quantitatively by a simple continuous-time random walk model. Instead, we argue that anomalous diffusion correlates with the existence of families of propagating periodic orbits. Finally we show that when a configuration with parallel scatterers is approached there is a crossover from normal to anomalous diffusion, with the diffusion coefficient exhibiting a power-law divergence.
Spatial variability of CO2 uptake in polygonal tundra
DEFF Research Database (Denmark)
Pirk, Norbert; Sievers, Jakob; Mertes, Jordan
2017-01-01
with an unmanned aerial vehicle (UAV) that mapped ice-wedge morphology to complement eddy covariance (EC) flux measurements of CO2. The analysis of spectral distributions showed that conventional EC methods do not accurately capture the turbulent CO2 exchange with a spatially heterogeneous surface that typically......The large spatial variability in Arctic tundra complicates the representative assessment of CO2 budgets. Accurate measurements of these heterogeneous landscapes are, however, essential to understanding their vulnerability to climate change. We surveyed a polygonal tundra lowland on Svalbard...... features small flux magnitudes. Nonlocal (low-frequency) flux contributions were especially pronounced during snow melt and introduced a large bias of -46 gC m(-2) to the annual CO2 budget in conventional methods (the minus sign indicates a higher uptake by the ecosystem). Our improved flux calculations...
Modeling slow deformation of polygonal particles using DEM
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
We introduce two improvements in the numerical scheme to simulate collision and slow shearing of irregular particles. First, we propose an alternative approach based on simple relations to compute the frictional contact forces. The approach improves efficiency and accuracy of the Discrete Element Method (DEM) when modeling the dynamics of the granular packing. We determine the proper upper limit for the integration step in the standard numerical scheme using a wide range of material parameters. To this end, we study the kinetic energy decay in a stress controlled test between two particles. Second, we show that the usual way of defining the contact plane between two polygonal particles is, in general, not unique which leads to discontinuities in the direction of the contact plane while particles move. To solve this drawback, we introduce an accurate definition for the contact plane based on the shape of the overlap area between touching particles, which evolves continuously in time.
Generalized Swept Mid-structure for Polygonal Models
Martin, Tobias
2012-05-01
We introduce a novel mid-structure called the generalized swept mid-structure (GSM) of a closed polygonal shape, and a framework to compute it. The GSM contains both curve and surface elements and has consistent sheet-by-sheet topology, versus triangle-by-triangle topology produced by other mid-structure methods. To obtain this structure, a harmonic function, defined on the volume that is enclosed by the surface, is used to decompose the volume into a set of slices. A technique for computing the 1D mid-structures of these slices is introduced. The mid-structures of adjacent slices are then iteratively matched through a boundary similarity computation and triangulated to form the GSM. This structure respects the topology of the input surface model is a hybrid mid-structure representation. The construction and topology of the GSM allows for local and global simplification, used in further applications such as parameterization, volumetric mesh generation and medical applications.
Intersection layout, traffic volumes and accidents.
Poppe, F.
1988-01-01
This paper reports on the accident research carried out as a part of a large project started in 1983. For this accident research an inventory was made of a large number of intersections.Recorded were layout features, accident data and estimates of traffic volumes. Attention will be given to the
The landscape of intersecting brane models
Douglas, M R; Douglas, Michael R.; Taylor, Washington
2007-01-01
We develop tools for analyzing the space of intersecting brane models. We apply these tools to a particular $T^6/Z^2_2$ orientifold which has been used for model building. We prove that there are a finite number of intersecting brane models on this orientifold which satisfy the Diophantine equations coming from supersymmetry. We give estimates for numbers of models with specific gauge groups, which we confirm numerically. We analyze the distributions and correlations of intersection numbers which characterize the numbers of generations of chiral fermions, and show that intersection numbers are roughly independent, with a characteristic distribution which is peaked around 0 and in which integers with fewer divisors are mildly suppressed. As an application, the number of models containing a gauge group $SU(3) \\times SU(2) \\times U(1)$ or $SU(4) \\times SU(2) \\times SU(2)$ and 3 generations of appropriate types of chiral matter is estimated to be order ${\\cal O} (10)$, in accord with previous explicit constructio...
Intersection of the Exponential and Logarithmic Curves
Boukas, Andreas; Valahas, Theodoros
2009-01-01
The study of the number of intersection points of y = a[superscript x] and y = log[subscript a]x can be an interesting topic to present in a single-variable calculus class. In this article, the authors present a classroom presentation outline involving the basic algebra and the elementary calculus of the exponential and logarithmic functions. The…
The Priority of Intersectionality in Academic Medicine.
Eckstrand, Kristen L; Eliason, Jennifer; St Cloud, Tiffani; Potter, Jennifer
2016-07-01
Recent societal events highlight inequities experienced by underrepresented and marginalized communities. These inequities are the impetus for ongoing efforts in academic medicine to create inclusive educational and patient care environments for diverse stakeholders. Frequently, approaches focus on singular populations or broad macroscopic concepts and do not always elucidate the complexities that arise at the intersection between multiple identities and life experiences. Intersectionality acknowledges multidimensional aspects of identity inclusive of historical, structural, and cultural factors. Understanding how multiple identity experiences impact different individuals, from patients to trainees to providers, is critical for improving health care education and delivery. Building on existing work within academic medicine, this Commentary outlines six key recommendations to advance intersectionality in academic medicine: embrace personal and collective loci of responsibility; examine and rectify unbalanced power dynamics; celebrate visibility and intersectional innovation; engage all stakeholders in the process of change; select and analyze meaningful metrics; and sustain the commitment to achieving health equity over time. Members of the academic medical community committed to advancing health equity can use these recommendations to promote and maintain meaningful changes that recognize and respond to the multidimensional voices and expressed needs of all individuals engaged in providing and receiving health care.
A Finite Model Property for Intersection Types
Directory of Open Access Journals (Sweden)
Rick Statman
2015-03-01
Full Text Available We show that the relational theory of intersection types known as BCD has the finite model property; that is, BCD is complete for its finite models. Our proof uses rewriting techniques which have as an immediate by-product the polynomial time decidability of the preorder <= (although this also follows from the so called beta soundness of BCD.