Search results for "SOFC"
showing 10 items of 660 documents
Group algebras whose units satisfy a group identity
1997
Let F G FG be the group algebra of a torsion group over an infinite field F F . Let U U be the group of units of F G FG . We prove that if U U satisfies a group identity, then F G FG satisfies a polynomial identity. This confirms a conjecture of Brian Hartley.
Orientation matters
2008
The optimal communication spanning tree (OCST) problem is a well known $\mathcal{NP}$-hard combinatorial optimization problem which seeks a spanning tree that satisfies all given communication requirements for minimal total costs. It has been shown that optimal solutions of OCST problems are biased towards the much simpler minimum spanning tree (MST) problem. Therefore, problem-specific representations for EAs like heuristic variants of edge-sets that are biased towards MSTs show high performance.In this paper, additional properties of optimal solutions for Euclidean variants of OCST problems are studied. Experimental results show that not only edges in optimal trees are biased towards low-…
An algorithm for the Rural Postman problem on a directed graph
1986
The Directed Rural Postman Problem (DRPP) is a general case of the Chinese Postman Problem where a subset of the set of arcs of a given directed graph is ‘required’ to be traversed at minimum cost. If this subset does not form a weakly connected graph but forms a number of disconnected components the problem is NP-Complete, and is also a generalization of the asymmetric Travelling Salesman Problem. In this paper we present a branch and bound algorithm for the exact solution of the DRPP based on bounds computed from Lagrangean Relaxation (with shortest spanning arborescence sub-problems) and on the fathoming of some of the tree nodes by the solution of minimum cost flow problems. Computation…
Fast and Simple Approximation of the Diameter and Radius of a Graph
2006
The increasing amount of data to be processed by computers has led to the need for highly efficient algorithms for various computational problems. Moreover, the algorithms should be as simple as possible to be practically applicable. In this paper we propose a very simple approximation algorithm for finding the diameter and the radius of an undirected graph. The algorithm runs in $O(m\sqrt{n})$ time and gives an additive error of $O(\sqrt{n})$ for a graph with n vertices and m edges. Practical experiments show that the results of our algorithm are close to the optimum and compare favorably to the 2/3-approximation algorithm for the diameter problem by Aingworth et al [1].
Games without repetitions on graphs with vertex disjoint cycles
1997
Games without repetitions on graphs with vertex disjoint cycles are considered. We show that the problem finding of the game partition in this class reduces to this problem for trees. A method of finding of the game partition for trees have been given in [2].
Goalkeeper: A Zero-Sum Exergame for Motivating Physical Activity
2021
Incentives and peer competition have so far been employed independently for increasing physical activity. In this paper, we introduce Goalkeeper, a mobile application that utilizes deposit contracts for motivating physical activity in group settings. Goalkeeper enables one to set up a physical exercise challenge with a group of peers that deposit a fixed amount of money for participating. If a peer fails to complete the challenge, Goalkeeper redistributes their deposit to those who managed to complete it (i.e., zero-sum game). We evaluated the potential of Goalkeeper in increasing physical activity with a total of 50 participants over the course of 2 months. Our findings suggest that deposi…
Gaussian quadrature rule for arbitrary weight function and interval
2019
Abstract A program for calculating abscissas and weights of Gaussian quadrature rules for arbitrary weight functions and intervals is reported. The program is written in Mathematica. The only requirement is that the moments of the weight function can be evaluated analytically in Mathematica. The result is a FORTRAN subroutine ready to be utilized for quadrature. Title of program: AWGQ Catalogue Id: ADVB_v1_0 Nature of problem Integration of functions. Versions of this program held in the CPC repository in Mendeley Data ADVB_v1_0; AWGQ; 10.1016/j.cpc.2004.12.010 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)
An Scalable matrix computing unit architecture for FPGA and SCUMO user design interface
2019
High dimensional matrix algebra is essential in numerous signal processing and machine learning algorithms. This work describes a scalable square matrix-computing unit designed on the basis of circulant matrices. It optimizes data flow for the computation of any sequence of matrix operations removing the need for data movement for intermediate results, together with the individual matrix operations’ performance in direct or transposed form (the transpose matrix operation only requires a data addressing modification). The allowed matrix operations are: matrix-by-matrix addition, subtraction, dot product and multiplication, matrix-by-vector multiplication, and matrix by scalar multiplication.…
The Mediation of Politics through Twitter: An Analysis of Messages posted during the Campaign for the German Federal Election 2013
2015
Patterns found in digital trace data are increasingly used as evidence of social phenomena. Still, the role of digital services not as mirrors but instead as mediators of social reality has been neglected. We identify characteristics of this mediation process by analyzing Twitter messages referring to politics during the campaign for the German federal election 2013 and comparing the thus emerging image of political reality with established measurements of political reality. We focus on the relationship between temporal dynamics in politically relevant Twitter messages and crucial campaign events, comparing dominant topics in politically relevant tweets with topics prominent in surveys and …
Explicit solutions of Riccati equations appearing in differential games
1990
Abstract In this paper an explicit closed form solution of Riccati differential matrix equations appearing in games theory is given.