528,091 research outputs found

    Immersive learning research

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    Editorial. Material for the special issue "Immersive Learning Research" of the Journal of Universal Computer Science.Welcome to the Journal of Universal Computer Science (J.UCS) special issue organized by the Immersive Learning Research Network (iLRN) following the 2017 iLRN conference. This issue includes eight papers on the focused topic "Immersive Learning Research", including extended versions of papers presented at iLRN 2017 and articles from the public call for papers.info:eu-repo/semantics/publishedVersio

    A Simple n-Dimensional Intrinsically Universal Quantum Cellular Automaton

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    We describe a simple n-dimensional quantum cellular automaton (QCA) capable of simulating all others, in that the initial configuration and the forward evolution of any n-dimensional QCA can be encoded within the initial configuration of the intrinsically universal QCA. Several steps of the intrinsically universal QCA then correspond to one step of the simulated QCA. The simulation preserves the topology in the sense that each cell of the simulated QCA is encoded as a group of adjacent cells in the universal QCA.Comment: 13 pages, 7 figures. In Proceedings of the 4th International Conference on Language and Automata Theory and Applications (LATA 2010), Lecture Notes in Computer Science (LNCS). Journal version: arXiv:0907.382

    On an almost-universal hash function family with applications to authentication and secrecy codes

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    Universal hashing, discovered by Carter and Wegman in 1979, has many important applications in computer science. MMH^*, which was shown to be Δ\Delta-universal by Halevi and Krawczyk in 1997, is a well-known universal hash function family. We introduce a variant of MMH^*, that we call GRDH, where we use an arbitrary integer n>1n>1 instead of prime pp and let the keys x=x1,,xkZnk\mathbf{x}=\langle x_1, \ldots, x_k \rangle \in \mathbb{Z}_n^k satisfy the conditions gcd(xi,n)=ti\gcd(x_i,n)=t_i (1ik1\leq i\leq k), where t1,,tkt_1,\ldots,t_k are given positive divisors of nn. Then via connecting the universal hashing problem to the number of solutions of restricted linear congruences, we prove that the family GRDH is an ε\varepsilon-almost-Δ\Delta-universal family of hash functions for some ε<1\varepsilon<1 if and only if nn is odd and gcd(xi,n)=ti=1\gcd(x_i,n)=t_i=1 (1ik)(1\leq i\leq k). Furthermore, if these conditions are satisfied then GRDH is 1p1\frac{1}{p-1}-almost-Δ\Delta-universal, where pp is the smallest prime divisor of nn. Finally, as an application of our results, we propose an authentication code with secrecy scheme which strongly generalizes the scheme studied by Alomair et al. [{\it J. Math. Cryptol.} {\bf 4} (2010), 121--148], and [{\it J.UCS} {\bf 15} (2009), 2937--2956].Comment: International Journal of Foundations of Computer Science, to appea

    Virtual Environments for Collaborative Innovation and Learning

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    Retalis, S., & Sloep, P. B. (2011). Virtual Environments for Collaborative Innovation and Learning. Journal of Universal Computer Science (J.UCS), 17(12), 1634-1637.Networked technologies, especially social software applications, provide new affordances that facilitate collaborative creativity among staff members of organizations. This editorial paper gives an overview of the scope of this special issue which focuses on the design of virtual environments for collaborative innovation and learning

    Efficient deterministic finite automata split-minimization derived from Brzozowski's algorithm

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    Minimization of deterministic finite automata is a classic problem in Computer Science which is still studied nowadays. In this paper, we relate the different split-minimization methods proposed to date, or to be proposed, and the algorithm due to Brzozowski which has been usually set aside in any classification of DFA minimization algorithms. In our work, we first propose a polynomial minimization method derived from a paper by Champarnaud et al. We also show how the consideration of some efficiency improvements on this algorithm lead to obtain an algorithm similar to Hopcroft s classic algorithm. The results obtained lead us to propose a characterization of the set of possible splitters.García Gómez, P.; López Rodríguez, D.; Vázquez-De-Parga Andrade, M. (2014). Efficient deterministic finite automata split-minimization derived from Brzozowski's algorithm. International Journal of Foundations of Computer Science. 25(6):679-696. doi:10.1142/S0129054114500282S679696256Vázquez de Parga, M., García, P., & López, D. (2013). A polynomial double reversal minimization algorithm for deterministic finite automata. Theoretical Computer Science, 487, 17-22. doi:10.1016/j.tcs.2013.03.005Courcelle, B., Niwinski, D., & Podelski, A. (1991). A geometrical view of the determinization and minimization of finite-state automata. Mathematical Systems Theory, 24(1), 117-146. doi:10.1007/bf02090394POLÁK, L. (2005). MINIMALIZATIONS OF NFA USING THE UNIVERSAL AUTOMATON. International Journal of Foundations of Computer Science, 16(05), 999-1010. doi:10.1142/s0129054105003431Gries, D. (1973). Describing an algorithm by Hopcroft. Acta Informatica, 2(2). doi:10.1007/bf00264025Blum, N. (1996). An O(n log n) implementation of the standard method for minimizing n-state finite automata. Information Processing Letters, 57(2), 65-69. doi:10.1016/0020-0190(95)00199-9Knuutila, T. (2001). Re-describing an algorithm by Hopcroft. Theoretical Computer Science, 250(1-2), 333-363. doi:10.1016/s0304-3975(99)00150-
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