| 41. |
- Lingas, Andrzej
(författare)
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Consequences of APSP, triangle detection, and 3SUM hardness for separation between determinism and non-determinism
- 2021
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Ingår i: Procedia Computer Science. - : Elsevier BV. - 1877-0509. ; 195, s. 163-171
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Tidskriftsartikel (refereegranskat)abstract
- Let NDTIME(f(n),g(n)) denote the class of problems solvable in O(g(n)) time by a multi-tape Turing machine using an f(n)-bit non-deterministic oracle, and let DTIME(g(n)) = NDTIME(0, g(n)). We show that if the all-pairs shortest paths problem (APSP) for directed graphs with N vertices and integer edge weights within a super-exponential range { -2Nk+o(1),.,2Nk+o(1)}, k≥1 does not admit a truly subcubic algorithm then for any ϵ>0, NDTIME([ 1/2 log2 n ], n)⊈DTIME(n1+12+k-ϵ). If the APSP problem does not admit a truly subcubic algorithm already when the edge weights are of moderate size then we obtain an even stronger implication, namely that for any ϵ>0, NDTIME([ 1/2 log2 n ], n)⊈DTIME(n1.5-ϵ). Similarly, we show that if the triangle detection problem (DT) in a graph on N vertices does not admit a truly sub-Nω-time algorithm then for any ϵ>0, NDTIME([ 1/2 log2 n ], n)⊈DTIME(nw/2-ϵ), where ω stands for the exponent of fast matrix multiplication. For the more general problem of detecting a minimum weight ω>-clique (MWCω>) in a graph with edge weights of moderate size, we show that the non-existence of truly sub-Nω>-time algorithm yields for any ϵ>0, NDTIME((ω>-2)[ 12 log2n ],n)⊈DTIME(n1+ω>-22-ϵ). Next, we show that if 3SUM for N integers in { -2Nk+o(1),.2Nk+o(1) } for some k≥0, does not admit a truly subquadratic algorithm then for any ϵ>0, NDTIME([ log2n ],n)⊈DTIME(n1+11+k-ϵ). Finally, we observe that the Exponential Time Hypothesis (ETH) implies NDTIME([ k log2n ],n)⊈DTIME(n) for some k>0, while the strong ETH (SETH) yields for any ϵ>0, NDTIME([ log2n ],n)⊈DTIME(n2-ϵ). For comparison, the strongest known result on separation between non-deterministic and deterministic time only asserts NDTIME(O(n),n)⊈DTIME(n).
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| 42. |
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| 43. |
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| 44. |
- von Heland, Franciska, et al.
(författare)
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Mediating science and action across multiple boundaries in the Coral Triangle
- 2014
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Ingår i: Global Environmental Change. - : Elsevier BV. - 0959-3780 .- 1872-9495. ; 29, s. 53-64
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Tidskriftsartikel (refereegranskat)abstract
- This study seeks to refine literature on boundary work by exploring how stakeholders in the Coral Triangle Initiative, an international agreement between six countries in Southeast Asia and the Pacific, are forging relations across various domains and governance levels, and the outcomes of this process. We do this in an effort to increase its relevance to multi-level environmental governance, and understand the challenges that face such governance. We are also interested in the pathways leading to policy outcomes that are perceived as salient, credible, and legitimate to all stakeholders involved in governance. The study shows that boundary work is challenged by resource inequalities resulting in limited knowledge diversity, blurred boundaries between science and politics, and misaligned scales. We conclude that boundary work has an important temporal dimension that has often been neglected, and that literature on boundary work must provide a conceptual guide to understand tradeoffs arising as a result of stakeholders' various strategies to engage in boundary work.
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| 45. |
- Bernhard, Jonte, 1953-, et al.
(författare)
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How does EER conceptualize its object of study : An exploration based on the ”Didaktik triangle”
- 2020
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Ingår i: Proceedings of SEFI 48th Annual Conference. - Enschede, NL. - 9782873520205 ; , s. 75-83
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Konferensbidrag (refereegranskat)abstract
- The Engineering Education Research (EER) community in Europe and across the globe has grown considerably in the past decades. There have been some examinations to date of the research corpus that has evolved, although these have been predominantly US-based. An emerging literature has started to chart the ways in which European EER-researchers have a distinctive tradition, which might at least in part be due to the influence of the European “Didaktik” tradition, which conceptualizes teaching and learning as fundamentally resting on an interplay between student, teacher, and the content (subject matter). This is represented in the “Didaktik triangle” where student, teacher, and the content are placed on the vertices of the triangle, and the sides of the triangle represent three important interrelations. This study compares the 50 most highly cited papers in each of the European Journal of Engineering Education (EJEE) and the US-based Journal of Engineering Education (JEE). Our analysis of how the topic(s) of the papers related to the “Didaktik triangle” shows that the conceptualization of the object of study in the EJEE papers was more related to the “Didaktik triangle” as a whole compared with papers published in JEE. The results of our study provide further evidence that there are, indeed, some differences in the aims of American and European EER. A global community would do well to try to draw on the strengths of both of these traditions.
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| 46. |
- Krüger, Oliver
(författare)
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An invariant for minimum triangle-free graphs
- 2019
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Ingår i: Australasian Journal of Combinatorics. - 2202-3518. ; 74, s. 371-388
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Tidskriftsartikel (refereegranskat)abstract
- We study the number of edges, e(G), in triangle-free graphs with a prescribed number of vertices, n(G), independence number, alpha(G), and number of cycles of length 4, N(C-4; G). In particular we show that 3e(G) - 17n(G) + 35 alpha(G) + N(C-4; G) >= 0 for all triangle-free graphs G. We also characterise the graphs that satisfy this inequality with equality. As a consequence we improve the previously best known lower bounds on the independence ratio i(G) = alpha(G)/n(G) for graphs of average degree at most 4 and girth at least 5, 6 or 7.
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| 47. |
- Winthereik Mathorne, Ole, et al.
(författare)
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An “Organizational Triangle” to Coordinate Talent Development : A Case Study in Danish Swimming
- 2020
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Ingår i: Case Studies in Sport and Exercise Psychology. - Champaign : Human Kinetics. - 2470-4849 .- 2470-4857. ; 4:1, s. 11-20
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Tidskriftsartikel (refereegranskat)abstract
- This case study in Danish swimming was informed by a holistic ecological approach in talent development and aimed to explore (a) collaborative relationships between the Danish swimming federation, a municipality, and a local swimming club, termed “an organizational triangle,” and (b) factors influencing the success of their collaboration at the local level. Data collection and analysis were guided by the athletic-talent-development-environment (working) model and a newly developed collaboration-success-factors (CSF) model. Methods included interviews with talent-development coordinators representing the organizations and analysis of documents. Results allowed the authors to transform the CSF (working) model into an empirical model containing the collaboration preconditions (e.g., power to make decisions), processes (e.g., strategic planning), and initiatives (e.g., efficient use of the swimming pool) and shared assumptions of the talent-development philosophy (e.g., long-term focus). The success of this organizational triangle was visible in the way the organizations increased the quality of talent development in the local swimming club. © 2020 Human Kinetics, Inc.
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| 48. |
- Owusu, Richard A., 1960-, et al.
(författare)
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African Regional Cooperation and Growth Triangle Strategies
- 2007. - 1
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Ingår i: Leadership and Management Studies in Sub-Sahara Africa. - San Diego : University Readers. - 9781934269121 ; , s. 114-122
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Bokkapitel (refereegranskat)abstract
- Whereas Africa has witnessed failure to achieve economic growth through formal regional cooperation efforts, Asia combined these efforts with other strategies and has been able to achieve positive results. Through formal regional cooperation and conscious support to key potential growth zones, Asian countries used growth triangle strategies (GT) that were aimed at increasing their competitiveness. This paper discusses the GT concept and proposes that African countries could benefit by adopting GT strategies. We illustrate our key arguments by comparing two regional cooperation processes in Africa: the East African Community (EAC) and the Economic Community of West African States (ECOWAS).
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| 49. |
- Brun, Anders, et al.
(författare)
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Computing Riemannian Normal Coordinates on Triangle Meshes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Imagine an ant walking around on the curved surface of a plant, a radio amateur planning to broadcast to a distant location across the globe or a pilot taking o from an airport - all of them are helped by egocentric maps of the world around them that shows directions and distances to various remote places. It is not surprising that this idea has already been used in cartography, where it is known as Azimuthal Equidistant Projection (AEP). If Earth is approximated by a sphere, distances and directions between two places are computed from arcs along great circles. In physics and mathematics, the same idea is known as Riemannian Normal Coordinates (RNC). It has been given a precise and general denition for surfaces (2-D), curved spaces (3-D) and generalized to smooth manifolds (N-D). RNC are the Cartesian coordinates of vectors that index points on the surface (or manifold) through the so called exponential map, which is a well known concept in dierential geometry. They are easily computed for a particular point if the inverse of the exponential map, the logarithm map, is known. Recently, RNC and similar coordinate systems have been used in computer graphics, visualization and related areas of research. In Fig. 1 for instance, RNC are used to produce a texture on the Stanford bunny through decal compositing. Given the growing use of RNC, which is further elaborated on in the next section, it is meaningful to develop accurate and reproducible techniques to compute this parameterization. In this paper, we describe a technique to compute RNC for surfaces represented by triangular meshes, which is the predominant representation of surfaces in computer graphics. The method that we propose has similarities to the Logmap framework, which has previously been developed for dimension reduction of unorganized point clouds in high-dimensional spaces, a.k.a. manifold learning. For this reason we sometimes refer to it as "Logmap for triangular meshes" or simply Logmap.
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| 50. |
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