115 research outputs found
Convex treemaps with bounded aspect ratio
Treemaps are a popular technique to visualize hierarchical data. The input is a weighted tree T where the weight of each node is the sum of the weights of its children. A treemap for T is a hierarchical partition of a rectangle into simply connected regions, usually rectangles. Each region represents a node of T and the area of each region is proportional to the weight of the corresponding node. An important quality criterium for treemaps is the aspect ratio of its regions. Unfortunately, one cannot bound the aspect ratio if the regions are restricted to be rectangles. Hence Onak and Sidiropoulos introduced polygonal
partitions, which use convex polygons. We are the first to obtain convex partitions with optimal aspect ratio O(depth(T )). We also consider the important special case that depth(T ) = 1, that is, single-level treemaps. We show how to construct convex single-level treemaps that use only four simple shapes for the regions and have aspect ratio at most 34/7
Naar een gereedschapskist voor constructieve ethiek
Tot voor kort werd er, ondanks de activiteiten van vele ethische commissies, nauwelijks methodologisch nagedacht over de inbreng van ethici in kwesties rond landbouw en voedselproductie. Het begin 2001 opgerichte Centrum voor Methodische Ethiek & Technology Assessment (META) beschouwt dit als een belangrijke lacune en ziet de ontwikkeling van een gereedschapskist voor ethische methodiek als haar eerste uitdaging. Bestaande ethische methodiek is er vooral op gericht ethische keuzen op een geordende en overzichtelijke manier te helpen maken. Deze methoden zijn bruikbaar maar eenzijdig. Dit rapport benadrukt dat er daarnaast behoefte is aan methoden die ethiek eerder de vorm geven van een constructie- dan van een keuzeproces. De rapportage besluit met een stappenplan voor constructieve ethiek dat uit twee fasen en zeven stappen bestaat
WAVE (Waarden in Vergelijking)
Aan de basis van deze studie ligt de behoefte aan meer inzicht in veranderende waarden in de samenleving. Waarden worden in dit rapport vanuit drie disciplines belicht: filosofie, sociologie en psychologie. Dit gebeurt in drie stappen. Om te beginnen schetst elke discipline een of meer theoretische invalshoeken voor het begrijpen van waarden. Vanuit elk van de drie disciplines zijn vervolgens een aantal waardenconflicten op het gebied van voedsel en groen geanalyseerd, met als doel de disciplinaire benaderingen te concretiseren en vergelijkbaar te maken. Ten slotte zijn de bevindingen vergeleken met het oog op overkoepelende patronen, spanningen, raakvlakken en aanbevelingen
Technical Design Report for the PANDA Solenoid and Dipole Spectrometer Magnets
This document is the Technical Design Report covering the two large
spectrometer magnets of the PANDA detector set-up. It shows the conceptual
design of the magnets and their anticipated performance. It precedes the tender
and procurement of the magnets and, hence, is subject to possible modifications
arising during this process.Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti
Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski,
Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy),
Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
Simulation results for future measurements of electromagnetic proton form
factors at \PANDA (FAIR) within the PandaRoot software framework are reported.
The statistical precision with which the proton form factors can be determined
is estimated. The signal channel is studied on the basis
of two different but consistent procedures. The suppression of the main
background channel, , is studied.
Furthermore, the background versus signal efficiency, statistical and
systematical uncertainties on the extracted proton form factors are evaluated
using two different procedures. The results are consistent with those of a
previous simulation study using an older, simplified framework. However, a
slightly better precision is achieved in the PandaRoot study in a large range
of momentum transfer, assuming the nominal beam conditions and detector
performance
Defining the Boundaries of Development wih Plasticity
International audienceThe concept of plasticity has always been present in the history of developmental biology, both within the theory of epigenesis and within morphogenesis studies. However this tradition relies also upon a genetic conception of plasticity. Founded upon the concepts of "phenotypic plasticity" and "reaction norm," this genetic conception focuses on the array of possible phenotypic change in relation to diversified environments. Another concept of plasticity can be found in recent publications by some developmental biologists (Gilbert, West-Eberhard). I argue that these authors adopt a "broad conception of plasticity" that is closely related to a notion of development as something that is ongoing throughout an organism's lifecycle, and has no clear-cut boundaries. However, I suggest that given a narrow conception of plasticity, one can define temporal boundaries for development that are linked to specific features of the morphological process, which are different from behavioral and physiological processes
Physics Performance Report for PANDA: Strong Interaction Studies with Antiprotons
To study fundamental questions of hadron and nuclear physics in interactions
of antiprotons with nucleons and nuclei, the universal PANDA detector will be
built. Gluonic excitations, the physics of strange and charm quarks and nucleon
structure studies will be performed with unprecedented accuracy thereby
allowing high-precision tests of the strong interaction. The proposed PANDA
detector is a state-of-the art internal target detector at the HESR at FAIR
allowing the detection and identification of neutral and charged particles
generated within the relevant angular and energy range. This report presents a
summary of the physics accessible at PANDA and what performance can be
expected.Comment: 216 page
Technical Design Report for the: PANDA Micro Vertex Detector
This document illustrates the technical layout and the expected performance
of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect
charged particles as close as possible to the interaction zone. Design criteria
and the optimisation process as well as the technical solutions chosen are
discussed and the results of this process are subjected to extensive Monte
Carlo physics studies. The route towards realisation of the detector is
outlined.Comment: 189 pages, 225 figures, 41 table
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