2,659 research outputs found
Octilinear Force-Directed Layout with Mental Map Preservation for Schematic Diagrams
We present an algorithm for automatically laying out metro map style schematics using a force-directed approach, where we use a localized version of the standard spring embedder forces combined with an octilinear magnetic force. The two types of forces used during layout are naturally conflicting, and the existing method of simply combining these to generate a resultant force does not give satisfactory results. Hence we vary the forces, emphasizing the standard forces in the beginning to produce a well distributed graph, with the octilinear forces
becoming prevalent at the end of the layout, to ensure that the key requirement of line angles at intervals of 45? is obtained. Our method is considerably faster than the more commonly used search-based approaches, and we believe the results are superior to the previous force-directed approach. We have further developed this technique to address the issues of dynamic schematic layout. We use a Delaunay triangulation to construct a schematic “frame”, which is used to retain relative node positions and permits full control of the level of mental map preservation.
This technique is the first to combine mental map preservation techniques with the additional layout criteria of schematic diagrams. To conclude, we present the results of a study to investigate the relationship between the level of mental map preservation and the user response time and accuracy
Spectra of magnetic perturbations triggered by pellets in JET plasmas
Aiming at investigating edge localised mode (ELM) pacing for future application on ITER, experiments have been conducted on JET injecting pellets in different plasma configurations, including high confinement regimes with type-I and type-III ELMs, low confinement regimes and Ohmically heated plasmas. The magnetic perturbations spectra and the toroidal mode number, n, of triggered events are compared with those of spontaneous ELMs using a wavelet analysis to provide good time resolution of short-lived coherent modes. It is found that—in all these configurations—triggered events have a coherent mode structure, indicating that pellets can trigger an MHD event basically in every background plasma. Two components have been found in the magnetic perturbations induced by pellets, with distinct frequencies and toroidal mode numbers. In high confinement regimes triggered events have similarities with spontaneous ELMs: both are seen to start from low toroidal mode numbers, then the maximum measured n increases up to about 10 within 0.3 ms before the ELM burst
On Embeddability of Buses in Point Sets
Set membership of points in the plane can be visualized by connecting
corresponding points via graphical features, like paths, trees, polygons,
ellipses. In this paper we study the \emph{bus embeddability problem} (BEP):
given a set of colored points we ask whether there exists a planar realization
with one horizontal straight-line segment per color, called bus, such that all
points with the same color are connected with vertical line segments to their
bus. We present an ILP and an FPT algorithm for the general problem. For
restricted versions of this problem, such as when the relative order of buses
is predefined, or when a bus must be placed above all its points, we provide
efficient algorithms. We show that another restricted version of the problem
can be solved using 2-stack pushall sorting. On the negative side we prove the
NP-completeness of a special case of BEP.Comment: 19 pages, 9 figures, conference version at GD 201
Who I Am: The Meaning of Early Adolescents’ Most Valued Activities and Relationships, and Implications for Self-Concept Research
Self-concept research in early adolescence typically measures young people’s self-perceptions of competence in specific, adult-defined domains. However, studies have rarely explored young people’s own views of valued self-concept factors and their meanings. For two major self domains, the active and the social self, this mixed-methods study identified factors valued most by 526 young people from socioeconomically diverse backgrounds in Ireland (10-12 years), and explored the meanings associated with these in a stratified subsample (n = 99). Findings indicate that self-concept scales for early adolescence omit active and social self factors and meanings valued by young people, raising questions about content validity of scales in these domains. Findings also suggest scales may under-represent girls’ active and social selves; focus too much on some school-based competencies; and, in omitting intrinsically salient self domains and meanings, may focus more on contingent (extrinsic) rather than true (intrinsic) self-esteem
Relativistic Heavy-Ion Physics: Experimental Overview
The field of relativistic heavy-ion physics is reviewed with emphasis on new
results and highlights from the first run of the Relativistic Heavy-Ion
Collider at BNL and the 15 year research programme at the SPS at CERN and the
AGS at BNL.Comment: 15 pages, 9 figures. Invited Talk at the Fourth International
Conference on Physics and Astrophysics of Quark Gluon Plasma, (ICPAQGP-2001)
Jaipur, India, November 26-30, 200
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