Topological Complexity of Locally Finite omega-Languages

to appear in Archive for Mathematical LogicInternational audienceLocally finite omega-languages were introduced by Ressayre in [Formal Languages defined by the Underlying Structure of their Words, Journal of Symbolic Logic, 53 (4), December 1988, p. 1009-1026]. These languages are defined by local sentences and extend omega-languages accepted by Büchi automata or defined by monadic second order sentences. We investigate their topological complexity. All locally finite omega languages are analytic sets, the class LOC_omega of locally finite omega-languages meets all finite levels of the Borel hierarchy and there exist some locally finite omega-languages which are Borel sets of infinite rank or even analytic but non-Borel sets. This gives partial answers to questions of Simonnet [Automates et Théorie Descriptive, Ph. D. Thesis, Université Paris 7, March 1992] and of Duparc, Finkel, and Ressayre [Computer Science and the Fine Structure of Borel Sets, Theoretical Computer Science, Volume 257 (1-2), 2001, p.85-105]

SPECIAL ISSUE ON MEMBRANE COMPUTING, Seventh Brainstorming Week on Membrane Computing

The present volume contains a selection of papers resulting from the Seventh Brainstorming Week on Membrane Computing (BWMC7), held in Sevilla, from February 2 to February 6, 2009. The meeting was organized by the Research Group on Natural Computing (RGNC) from Department of Computer Science and Artificial Intelligence of Sevilla University. The previous editions of this series of meetings were organized in Tarragona (2003), and Sevilla (2004 – 2008). After the first BWMC, a special issue of Natural Computing – volume 2, number 3, 2003, and a special issue of New Generation Computing – volume 22, number 4, 2004, were published; papers from the second BWMC have appeared in a special issue of Journal of Universal Computer Science – volume 10, number 5, 2004, as well as in a special issue of Soft Computing – volume 9, number 5, 2005; a selection of papers written during the third BWMC has appeared in a special issue of International Journal of Foundations of Computer Science – volume 17, number 1, 2006); after the fourth BWMC a special issue of Theoretical Computer Science was edited – volume 372, numbers 2-3, 2007; after the fifth edition, a special issue of International Journal of Unconventional Computing was edited – volume 5, number 5, 2009; finally, a selection of papers elaborated during the sixth BWMC has appeared in a special issue of Fundamenta Informatica

Zonotopes, toric arrangements, and generalized Tutte polynomials

We introduce a multiplicity Tutte polynomial M(x, y), which generalizes the ordinary one and has applications to zonotopes and toric arrangements. We prove that M(x, y) satisfies a deletion-restriction recurrence and has positive coefficients. The characteristic polynomial and the Poincar\ue9 polynomial of a toric arrangement are shown to be specializations of the associated polynomial M(x, y), likewise the corresponding polynomials for a hyperplane arrangement are specializations of the ordinary Tutte polynomial. Furthermore, M(1, y) is the Hilbert series of the related discrete Dahmen-Micchelli space, while M(x, 1) computes the volume and the number of integral points of the associated zonotope. \ua9 2010 Discrete Mathematics and Theoretical Computer Science (DMTCS), Nancy, France

Solving the At-Most-Once Problem with Nearly Optimal Effectiveness

We present and analyze a wait-free deterministic algorithm for solving the at-most-once problem: how m shared-memory fail-prone processes perform asynchronously n jobs at most once. Our algorithmic strategy provides for the first time nearly optimal effectiveness, which is a measure that expresses the total number of jobs completed in the worst case. The effectiveness of our algorithm equals n-2m+2. This is up to an additive factor of m close to the known effectiveness upper bound n-m+1 over all possible algorithms and improves on the previously best known deterministic solutions that have effectiveness only n-log m o(n). We also present an iterative version of our algorithm that for any $m = O\left(\sqrt[3+\epsilon]{n/\log n}\right)$ is both effectiveness-optimal and work-optimal, for any constant $\epsilon > 0$. We then employ this algorithm to provide a new algorithmic solution for the Write-All problem which is work optimal for any $m=O\left(\sqrt[3+\epsilon]{n/\log n}\right)$.Comment: Updated Version. A Brief Announcement was published in PODC 2011. An Extended Abstract was published in the proceeding of ICDCN 2012. A full version was published in Theoretical Computer Science, Volume 496, 22 July 2013, Pages 69 - 8

Preface Volume 65, Issue 1

AbstractThis volume contains the Proceedings of the Fifth Workshop on Coalgebraic Methods in Computer Science (CMCS'2002). The Workshop was held in Grenoble, France on April 6--7 2002, as satellite event to ETAPS'2002.Over the last few years it has become clear that a great variety of state-based dynamical systems, like transition systems, automata, process calculi and class-based systems can be captured uniformly as coalgebras. The aim of the CMCS workshops is to bring together researchers with a common interest in the theory and application of coalgebras. The five CMCS volumes demonstrate that coalgebra is developing into a field of its own, presenting a deep mathematical foundation and a growing field of applications and interactions with various other fields, such as modal logic, category theory, dynamical systems, control systems, object-oriented and concurrent programming, formal systems specifications, algebra, analysis, combinatorics, and set theory.The papers in this volume were reviewed by the program committee: Jiri Adamek(Department of Computer Science, Technical University of Braunschweig)Alexandru Baltag(Department of Computer Science, Oxford University)H. Peter Gumm(Department of Mathematics and Computer Science, University of Marburg)Jesse Hughes(Department of Computer Science, University of Nijmegen)Bart Jacobs(Department of Computer Science, University of Nijmegen)Alexander Kurz(Department of Software Technology, CWI)Marina Lenisa(Department of Mathematics and Computer Science, University of Udine)Ugo Montanari(Department of Computer Science, University of Pisa)Larry Moss(Department of Mathematics, Indiana University)Ataru T. Nakagawa(SRA Key Technology Laboratory, Tokyo)John Power(Department of Computer Science, The University of Edinburgh)Horst Reichel(Institute of Theoretical Computer Science, Dresden University of Technology)Jan Rutten(Department of Software Technology, CWI)Several outside reviewers also assisted. CMCS received 20 submissions and accepted 15 of them. In addition, there were two invited speakers: Jose Meseguer and Luigi Santocanale. Their papers appear in this volume along with the 15 submitted contributions. We are grateful to everyone who sent us papers, and we regret that the length of the conference did not allow more papers to be presented.We thank the organizers of ETAPS'2002 for their help and encouragement. Special thanks to Rachid Echahed for his constant help with the organization of the workshop, and also to Mike Mislove for his work as a Managing Editor of the ENTCS series. Their efforts have been crucial for the success of CMCS'2002.September 1, 2002 Lawrence S. Mos

The determinants of transverse tubular volume in resting skeletal muscle.

The transverse tubular (t)-system of skeletal muscle couples sarcolemmal electrical excitation with contraction deep within the fibre. Exercise, pathology and the composition of the extracellular fluid (ECF) can alter t-system volume (t-volume). T-volume changes are thought to contribute to fatigue, rhabdomyolysis and disruption of excitation-contraction coupling. However, mechanisms that underlie t-volume changes are poorly understood. A multicompartment, history-independent computer model of rat skeletal muscle was developed to define the minimum conditions for t-volume stability. It was found that the t-system tends to swell due to net ionic fluxes from the ECF across the access resistance. However, a stable t-volume is possible when this is offset by a net efflux from the t-system to the cell and thence to the ECF, forming a net ion cycle ECF→t-system→sarcoplasm→ECF that ultimately depends on Na(+)/K(+)-ATPase activity. Membrane properties that maximize this circuit flux decrease t-volume, including PNa(t) > PNa(s), PK(t) < PK(s) and N(t) < N(s) [P, permeability; N, Na(+)/K(+)-ATPase density; (t), t-system membrane; (s), sarcolemma]. Hydrostatic pressures, fixed charges and/or osmoles in the t-system can influence the magnitude of t-volume changes that result from alterations in this circuit flux. Using a parameter set derived from literature values where possible, this novel theory of t-volume was tested against data from previous experiments where t-volume was measured during manipulations of ECF composition. Predicted t-volume changes correlated satisfactorily. The present work provides a robust, unifying theoretical framework for understanding the determinants of t-volume.JAF was supported by a David Phillips Fellowship (BB/FO23863/1) awarded by the Biotechnology and Biological Sciences Research Council (UK). JS was supported by the Agency for Science, Technology and Research (Singapore) and a Caius Medical Association summer studentship from Gonville and Caius College, University of Cambridge.This is the final version. It was first published by Wiley at http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.281170/abstract

A Survey on Continuous Time Computations

We provide an overview of theories of continuous time computation. These theories allow us to understand both the hardness of questions related to continuous time dynamical systems and the computational power of continuous time analog models. We survey the existing models, summarizing results, and point to relevant references in the literature

Smartphone App Security: Vulnerabilities and Implementations

Due to the high occupancy volume of smartphones in mode society, more and more developers join the smartphone app market and develop various mobile applications that could benefit out life in many ways. However, smartphone apps are often blamed for insecurities due to smartphone technologies as well as inexperienced app developers. In this thesis work, we study smartphone app security vulnerabilities due to either improper implementations or improper use of smartphone technologies. More specifically, we study potential security vulnerabilities in three categories of apps: apps which use the secure socket layer(SSL) protocol for secure communication, apps which use the WebView technology, and apps which are HTML5-based. For each category of apps, we analyze the underlying technologies to show the cause of vulnerabilities, and develop instruction materials for each of the three validation attacks we have implemented and turn them into security teaching labs. These security teaching labs aim to help students to understand the theoretical attack concepts in and accurate and understandable way and cultivate the hacking mindset.Master of Science (MS)Computer and Information Science, College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/143522/1/Linxi-thesis-submission.pdfDescription of Linxi-thesis-submission.pdf : Thesi