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An efficient approach to achieve compositionality using optimized multi-version object based transactional systems Inf. Comput. (IF 0.872) Pub Date : 2021-01-19 Chirag Juyal; Sandeep Kulkarni; Sweta Kumari; Sathya Peri; Archit Somani
In the modern era of multi-core systems, the main aim is to utilize the cores properly. This utilization can be done by concurrent programming. But developing a flawless and well-organized concurrent program is difficult. Software Transactional Memory Systems (STMs) are a convenient programming interface which assist the programmer to access the shared memory concurrently without worrying about consistency
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Ring Exploration with Myopic Luminous Robots Inf. Comput. (IF 0.872) Pub Date : 2021-01-11 Fukuhito Ooshita; Sébastien Tixeuil
We investigate exploration algorithms for autonomous mobile robots evolving in uniform ring-shaped networks. Different from the usual Look-Compute-Move (LCM) model, we consider two characteristics: myopia and luminosity. Myopia means each robot has a limited visibility. We consider the weakest assumption for myopia: each robot can only observe its neighboring nodes. Luminosity means each robot maintains
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Search by a metamorphic robotic system in a finite 2D square Grid Inf. Comput. (IF 0.872) Pub Date : 2021-01-11 Keisuke Doi; Yukiko Yamauchi; Shuji Kijima; Masafumi Yamashita
We consider search in an unknown finite 2D square grid by a metamorphic robotic system consisting of anonymous memory-less modules. Each module autonomously moves while executing a common distributed algorithm and the modules collectively form a robotic system by keeping connectivity. The number of shapes of the metamorphic robotic system grows as the number of modules increases, and a shape of the
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Load Balanced Distributed Directories Inf. Comput. (IF 0.872) Pub Date : 2021-01-11 Shishir Rai; Gokarna Sharma; Costas Busch; Maurice Herlihy
We present LB-Spiral, a novel distributed directory protocol for shared objects, suitable for large-scale distributed shared memory systems. Each shared object has an owner node that can modify its value. The ownership may change by moving the object from one node to another in response to move requests. The value of an object can be read by other nodes with lookup requests. The distinctive feature
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On Fast Pattern Formation by Autonomous Robots Inf. Comput. (IF 0.872) Pub Date : 2021-01-09 Ramachandran Vaidyanathan; Gokarna Sharma; Jerry Trahan
We consider the fundamental problem of arranging a set of n autonomous robots (points) on a real plane according to an arbitrary given pattern. Each robot operates in a, largely oblivious, look-compute-move step. We measure the time complexity of our algorithms in “epochs,” which denotes the minimum time interval in which every robot performs at least one look-compute-move step. We present a framework
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Simple and fast approximate counting and leader election in populations Inf. Comput. (IF 0.872) Pub Date : 2021-01-08 Othon Michail; Paul G. Spirakis; Michail Theofilatos
We study the problems of leader election and population size counting for population protocols: networks of finite-state anonymous agents that interact randomly under a uniform random scheduler. We provide simple protocols for approximate counting of the size of the population and for leader election. We show a protocol for leader election that terminates in O(log2nlogm) parallel time, where m is
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A Self-Stabilizing Hashed Patricia Trie Inf. Comput. (IF 0.872) Pub Date : 2021-01-08 Till Knollmann; Christian Scheideler
While a lot of research in distributed computing has covered solutions for self-stabilizing computing and topologies, there is far less work on self-stabilization for distributed data structures. Considering crashing peers in peer-to-peer networks, it should not be taken for granted that a distributed data structure remains intact. In this work, we present a self-stabilizing protocol for a distributed
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Clairvoyant State Machine Replication Inf. Comput. (IF 0.872) Pub Date : 2021-01-08 Rida Bazzi; Maurice Herlihy
We consider the state machine replication problem in semi-synchronous systems subject to Byzantine server failures. We propose a new solution to the problem in the form of a protocol for the generalized consensus problem. The protocol solves the consensus problem in a setting in which information about conflicts between transactions is available (such information can be in the form of transaction read
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How does adiabatic quantum computation fit into quantum automata theory? Inf. Comput. (IF 0.872) Pub Date : 2021-01-07 Tomoyuki Yamakami
Quantum computation has emerged as a powerful computational medium of our time, having demonstrated the remarkable efficiency in factoring a positive integer and searching databases faster than any currently known classical computing algorithm. Adiabatic evolution of quantum systems have been studied as a potential means that physically realizes quantum computation. Up to now, all the research on adiabatic
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Nondeterministic right one-way jumping finite automata Inf. Comput. (IF 0.872) Pub Date : 2021-01-06 Simon Beier; Markus Holzer
Right-one way jumping finite automata are deterministic devices that process their input in a discontinuous fashion. We generalise these devices to nondeterministic machines. More precisely we study the impact on the computational power of these machines when allowing multiple initial states and/or a nondeterministic transition function including spontaneous or λ-transitions. We show inclusion relations
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Maximal State Complexity and Generalized de Bruijn Words Inf. Comput. (IF 0.872) Pub Date : 2021-01-06 Daniel Gabric; Štěpán Holub; Jeffrey Shallit
We compute the exact maximum state complexity for the language consisting of m words of length N, and characterize languages achieving the maximum. We also consider a special case, namely languages C(w) consisting of the conjugates of a single word w. The words for which the maximum state complexity of C(w) is achieved turn out to be a natural generalization of de Bruijn words. We show that generalized
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Operational Union-Complexity Inf. Comput. (IF 0.872) Pub Date : 2021-01-06 Benedek Nagy
Union-free languages are described by regular expressions using only concatenation and Kleene-star. Every regular language can be given as a union of finitely many union-free languages. By the minimal number of union-free languages needed in such union-free decompositions of a regular language, its union-complexity is defined. In this paper, the union-complexity of the languages obtained by various
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Descriptional Complexity of Iterated Uniform Finite-State Transducers Inf. Comput. (IF 0.872) Pub Date : 2021-01-06 Martin Kutrib; Andreas Malcher; Carlo Mereghetti; Beatrice Palano
We introduce the deterministic computational model of an iterated uniform finite-state transducer (iufst). An iufst performs the same length-preserving transduction on several left-to-right sweeps. The first sweep takes place on the input string, while any other sweep processes the output of the previous one. The iufst accepts by halting at the end of a sweep in an accepting state. First, we focus
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State complexity of GF(2)-operations on unary languages Inf. Comput. (IF 0.872) Pub Date : 2021-01-06 Alexander Okhotin; Elizaveta Sazhneva
The paper investigates the state complexity of two operations on regular languages, known as GF(2)-concatenation and GF(2)-inverse of Bakinova et al. (2018) [1], in the case of a one-symbol alphabet. The GF(2)-concatenation is a variant of the classical concatenation obtained by replacing Boolean logic in its definition with the GF(2) field; it is proved that GF(2)-concatenation of two unary languages
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On the Computational Completeness of Matrix Simple Semi-Conditional Grammars Inf. Comput. (IF 0.872) Pub Date : 2021-01-06 Henning Fernau; Lakshmanan Kuppusamy; Indhumathi Raman
In matrix grammars, context-free rules have to be applied in a certain order. However in simple semi-conditional (SSC) grammars, the derivations are controlled either by a permitting string or by a forbidden string associated to each rule. Typical descriptional complexity measures incorporate the number of nonterminals and the number of rules per matrix in a matrix grammar. In SSC grammars, the maximum
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Structural properties of NFAs and growth rates of nondeterminism measures Inf. Comput. (IF 0.872) Pub Date : 2021-01-05 Chris Keeler; Kai Salomaa
Tree width (respectively, string path width) measures the maximal number of partial (respectively, complete) computations of a nondeterministic finite automaton on an input of given length. We characterize polynomial and exponential growth rates of tree width and string path width by structural properties of the corresponding nondeterministic finite automaton (NFA). As the main result we show that
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Rule synchronization for tissue P systems Inf. Comput. (IF 0.872) Pub Date : 2021-01-04 Bosheng Song; Linqiang Pan
Maximally parallel manner is a usual rule application strategy for P systems, where a maximal set of enabled rules are chosen and each rule in the set is applied as many times as possible. In this work, we consider a rule application strategy, rule synchronization, where some synchronization sets of rules are given, a rule in a synchronization set of rules can be applied only if all rules in the set
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A novel learning algorithm for Büchi automata based on family of DFAs and classification trees Inf. Comput. (IF 0.872) Pub Date : 2020-12-30 Yong Li; Yu-Fang Chen; Lijun Zhang; Depeng Liu
In this paper, we propose a novel algorithm to learn a Büchi automaton from a teacher who knows an ω-regular language. The learned Büchi automaton can be a nondeterministic Büchi automaton or a limit deterministic Büchi automaton. The learning algorithm is based on learning a formalism called family of DFAs (FDFAs) recently proposed by Angluin and Fisman. The main catch is that we use a classification
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Default logic and bounded treewidth Inf. Comput. (IF 0.872) Pub Date : 2020-12-23 Johannes K. Fichte; Markus Hecher; Irina Schindler
In this paper, we study Reiter's propositional default logic when the treewidth of a certain graph representation (semi-primal graph) of the input theory is bounded. We establish a dynamic programming algorithm on tree decompositions that decides whether a theory has a consistent stable extension ( Cons ). Our algorithm can even be used to enumerate all generating defaults ( EnumSD ) that lead to stable
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Pomset Bisimulation and Unfolding for Reset Petri Nets Inf. Comput. (IF 0.872) Pub Date : 2020-12-17 Thomas Chatain; Maurice Comlan; David Delfieu; Loïg Jezequel; Olivier-Henri Roux
Reset Petri nets are a particular class of Petri nets where transition firings can remove all tokens from a place without checking if this place actually holds tokens or not. In this paper we look at partial order semantics of reset Petri nets. In particular, we propose a pomset bisimulation for comparing their concurrent behaviours. Building on this pomset bisimulation we then propose a generalization
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A Periodicity Lemma for Partial Words Inf. Comput. (IF 0.872) Pub Date : 2020-12-16 Tomasz Kociumaka; Jakub Radoszewski; Wojciech Rytter; Tomasz Waleń
We investigate the function L(h,p,q), called here the length function, such that L(h,p,q) is the minimum length which guarantees that a natural extension of the periodicity lemma is valid for partial words with h holes and (so-called strong) periods p,q. In a series of papers, the formulae for the length function, in terms of p and q, were provided for each fixed h≤7. We demystify the generic structure
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Context-Free Timed Formalisms: Robust Automata and Linear Temporal Logics Inf. Comput. (IF 0.872) Pub Date : 2020-12-16 Laura Bozzelli; Aniello Murano; Adriano Peron
The paper is focused on automata and linear temporal logics for describing the behaviour of real-time pushdown reactive systems. The goal of the paper is to bridge (both in the context of automata and linear temporal logics) tractable formalisms specialized for expressing separately dense-time real-time properties and context-free properties though preserving tractability in the combined setting. As
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Formal languages over GF(2) Inf. Comput. (IF 0.872) Pub Date : 2020-12-16 Ekaterina Bakinova; Artem Basharin; Igor Batmanov; Konstantin Lyubort; Alexander Okhotin; Elizaveta Sazhneva
Variants of the union and concatenation operations on formal languages are investigated, in which Boolean logic in the definitions (that is, conjunction and disjunction) is replaced with the operations in the two-element field GF(2) (conjunction and exclusive OR). Union is thus replaced with symmetric difference, whereas concatenation gives rise to a new GF(2)-concatenation operation, which is notable
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Learners Based on Transducers Inf. Comput. (IF 0.872) Pub Date : 2020-12-15 Sanjay Jain; Shao Ning Kuek; Eric Martin; Frank Stephan
The learners considered in this paper process an infinite text of data containing all members of the set to be learnt in cycles, one word in each cycle, and maintain as a long term memory a string which provides all internal data the learner can use in the next cycle. Updating of these strings is usually done by either recursive or automatic learners. The present work looks at transduced learners,
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Reversibility of computations in graph-walking automata Inf. Comput. (IF 0.872) Pub Date : 2020-10-09 Michal Kunc; Alexander Okhotin
Graph-walking automata (GWA) are finite-state devices that traverse graphs given as an input by following their edges; they have been studied both as a theoretical notion and as a model of pathfinding in robotics. If a graph is regarded as the set of memory configurations of a certain abstract machine, then various families of devices can be described as GWA: such are two-way finite automata, their
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An efficient eCK secure identity based Two Party Authenticated Key Agreement scheme with security against active adversaries Inf. Comput. (IF 0.872) Pub Date : 2020-09-22 Renu Mary Daniel; Elijah Blessing Rajsingh; Salaja Silas
A Two-Party Authenticated Key Agreement (2-PAKA) protocol facilitates two communicating entities to equally contribute to the establishment of a shared session key. IDentity-based 2-PAKA (ID-2-PAKA) protocols are widely researched, since it eliminates the need for explicit public-key verification using digital certificates. Over the years, ID-2-PAKA protocols with perfect forward secrecy and Key Generation
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On the universal steganography of optimal rate Inf. Comput. (IF 0.872) Pub Date : 2020-10-14 Sebastian Berndt; Maciej Liśkiewicz
In this work, we present the first secure stegosystem in the common computational model which, for any communication channel, is provably secure, reliable, and has nearly optimal bandwidth, but needs super-polynomial time. This solves several open problems about secret-key steganography in the computational model. In particular, our result answers affirmatively the question whether there exists a secure
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Online recognition of dictionary with one gap Inf. Comput. (IF 0.872) Pub Date : 2020-10-28 Amihood Amir; Avivit Levy; Ely Porat; B. Riva Shalom
We formalize and examine the online Dictionary Recognition with One Gap problem (DROG) which is the following. Preprocess a dictionary D of d patterns each containing a special gap symbol that matches any string, so that given a text arriving online a character at a time, all patterns from D which are suffixes of the text that has arrived so far and have not been reported yet, are reported before the
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Time-bounded termination analysis for probabilistic programs with delays Inf. Comput. (IF 0.872) Pub Date : 2020-11-04 Ming Xu; Yuxin Deng
This paper investigates the model of probabilistic program with delays (PPD) that consists of a few program blocks. Performing each block has an additional time-consumption—waiting to be executed—besides the running time. We interpret the operational semantics of PPD by Markov automata with a cost structure on transitions. Our goal is to measure those individual execution paths of a PPD that terminates
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Weighted models for higher-order computation Inf. Comput. (IF 0.872) Pub Date : 2020-11-12 James Laird
We study a class of quantitative models for higher-order computation: Lafont categories with (infinite) biproducts. Each of these has a complete “internal semiring” and can be enriched over its modules. We describe a semantics of nondeterministic PCF weighted over this semiring in which fixed points are obtained from the bifree algebra over its exponential structure. By characterizing them concretely
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An extended coding theorem with application to quantum complexities Inf. Comput. (IF 0.872) Pub Date : 2020-11-17 Samuel Epstein
This paper introduces a new inequality in algorithmic information theory that can be seen as an extended coding theorem. This inequality has applications in new bounds between quantum complexity measures.
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A parametric framework for reversible π-calculi Inf. Comput. (IF 0.872) Pub Date : 2020-11-12 Doriana Medić; Claudio Antares Mezzina; Iain Phillips; Nobuko Yoshida
This paper presents a study of causality in a reversible, concurrent setting. There exist various notions of causality in π-calculus, which differ in the treatment of parallel extrusions of the same name. Hence, by using a parametric way of bookkeeping the order and the dependencies among extruders it is possible to map different causal semantics into the same framework. Starting from this simple observation
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Weighted Automata Computation of Edit Distances with Consolidations and Fragmentations Inf. Comput. (IF 0.872) Pub Date : 2020-11-24 Mathieu Giraud; Florent Jacquemard
We study edit distances between strings, based on weighted operations such as character substitutions, insertions, deletions and additionally consolidations and fragmentations. The two latter operations transform a sequence of characters into one character and vice-versa. They correspond to the compression and expansion in Dynamic Time-Warping algorithms for speech recognition and are also used for
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Weighted operator precedence languages Inf. Comput. (IF 0.872) Pub Date : 2020-11-24 Manfred Droste; Stefan Dück; Dino Mandrioli; Matteo Pradella
In the last years renewed investigation of operator precedence languages (OPL) led to discover important properties thereof: OPL are closed with respect to all major operations, are characterized, besides by the original grammar family, in terms of an automata family (OPA) and an MSO logic; furthermore they significantly generalize the well-known visibly pushdown languages (VPL). A different area of
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Syntactic Stochastic Processes: Definitions, Models, and Related Inference Problems Inf. Comput. (IF 0.872) Pub Date : 2020-11-24 Francesco Carravetta; Langford B. White
We define a Syntactic Stochastic Process (SSP) as a stochastic process valued in the set of terminal symbols of a grammar, and whose realizations are terminal strings generated by some stochastic grammar. We consider first the case of a Stochastic Context-Free Grammar (SCFGs) generating the process and show that any SSP generated by an SCFG (a context free process) can be consistently indexed by a
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The role of randomness in the broadcast congested clique model Inf. Comput. (IF 0.872) Pub Date : 2020-11-23 Florent Becker; Pedro Montealegre; Ivan Rapaport; Ioan Todinca
We study the role of randomness in the broadcast congested clique model. This is message-passing model of distributed computation where the nodes of a network know their local neighborhoods and they broadcast, in synchronous rounds, messages that are visible to every other node. This works aims to separate three different settings: deterministic protocols, randomized protocols with private coins, and
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Dynamics of reputation in mobile agents systems and weighted timed automata Inf. Comput. (IF 0.872) Pub Date : 2020-11-23 Bogdan Aman; Gabriel Ciobanu
The reputation of a process is based on its past and present behaviour; it evolves in time depending on several factors including the actions performed, the reputation of its interacting processes and locations where the process resides. We design a calculus of mobile agents in distributed systems able to handle the dynamics of reputation which changes over time depending on specified factors. The
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On the amount of nonconstructivity in learning formal languages from text Inf. Comput. (IF 0.872) Pub Date : 2020-11-23 Sanjay Jain; Frank Stephan; Thomas Zeugmann
Nonconstructive computations by various types of machines and automata have been considered by, for example, Karp and Lipton [21], and Freivalds [9], [10]. They allow to regard more complicated algorithms from the viewpoint of much more primitive computational devices. The amount of nonconstructivity is a quantitative characterization of the distance between types of computational devices with respect
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Logic for ω-pushdown automata Inf. Comput. (IF 0.872) Pub Date : 2020-11-20 Manfred Droste; Sven Dziadek; Werner Kuich
Context-free languages of infinite words have recently found increasing interest. Here, we will present a second-order logic with the same expressive power as Büchi or Muller pushdown automata for infinite words. This extends fundamental logical characterizations of Büchi, Elgot, Trakhtenbrot for regular languages of finite and infinite words and a more recent logical characterization of Lautemann
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Probabilistic automata of bounded ambiguity Inf. Comput. (IF 0.872) Pub Date : 2020-11-19 Nathanaël Fijalkow; Cristian Riveros; James Worrell
Probabilistic automata are an extension of nondeterministic finite automata in which transitions are annotated with probabilities. Despite its simplicity, this model is very expressive and many of the associated algorithmic questions are undecidable. In this work we focus on the emptiness problem (and its variant the value problem), which asks whether a given probabilistic automaton accepts some word
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Regular transducer expressions for regular transformations Inf. Comput. (IF 0.872) Pub Date : 2020-11-19 Vrunda Dave; Paul Gastin; Shankara Narayanan Krishna
Functional MSO transductions, deterministic two-way transducers, as well as streaming string transducers are all equivalent models for regular functions. In this paper, we show that every regular function, either on finite words or on infinite words, captured by a deterministic two-way transducer, can be described with a regular transducer expression (RTE ). For infinite words, the two-way transducer
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Bisimulation metrics and norms for real-weighted automata Inf. Comput. (IF 0.872) Pub Date : 2020-11-18 Borja Balle; Pascale Gourdeau; Prakash Panangaden
We develop a new bisimulation (pseudo)metric for weighted finite automata (WFA) that generalizes Boreale's linear bisimulation relation. Our metrics are induced by seminorms on the state space of WFA. Our development is based on spectral properties of sets of linear operators. In particular, the joint spectral radius of the transition matrices of WFA plays a central role. We also study continuity properties
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Costs and rewards in priced timed automata Inf. Comput. (IF 0.872) Pub Date : 2020-11-17 Martin Fränzle; Mahsa Shirmohammadi; Mani Swaminathan; James Worrell
We consider Pareto analysis of reachable states in multi-priced timed automata (MPTA). An MPTA is a timed automaton equipped with multiple observers that record costs (to be minimised) and rewards (to be maximised) that are accumulated along a computation. Each observer has a non-negative derivative that is constant in each location of the automaton. We study the Pareto Domination Problem, which asks
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Principal Abstract Families of Weighted Tree Languages Inf. Comput. (IF 0.872) Pub Date : 2020-11-16 Zoltán Fülöp; Heiko Vogler
We introduce semiring-weighted regular tree grammars with storage where the semiring is complete. We show that the class of weighted tree languages generated by them is a principal abstract family of weighted tree languages provided that the semiring is commutative, the rank of symbols occurring in trees is bounded by a global parameter, and that the storage is finitely encoded and contains a reset
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Preservation of normality by transducers Inf. Comput. (IF 0.872) Pub Date : 2020-11-13 Olivier Carton; Elisa Orduna
We consider input deterministic finite state transducers with infinite inputs and infinite outputs, and we consider the property of Borel normality on infinite words. When these transducers are given by a strongly connected set of states, and when the input is a Borel normal sequence, the output is an infinite word such that every word has a frequency given by a weighted automaton over the rationals
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Weighted propositional configuration logics: A specification language for architectures with quantitative features Inf. Comput. (IF 0.872) Pub Date : 2020-11-13 Paulina Paraponiari; George Rahonis
We introduce and investigate a weighted propositional configuration logic over commutative semirings. Our logic is intended to serve as a specification language for software architectures with quantitative features. We prove an efficient construction of full normal forms and decidability of equivalence of formulas in this logic. We illustrate the motivation of this work by describing well-known architectures
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What's decidable about weighted automata? Inf. Comput. (IF 0.872) Pub Date : 2020-11-13 Shaull Almagor; Udi Boker; Orna Kupferman
Weighted automata map input words to numerical values. Applications of weighted automata include formal verification of quantitative properties, as well as text, speech, and image processing. In the 90's, Krob studied the decidability of problems on rational series, which strongly relate to weighted automata. In particular, it follows from Krob's results that the universality problem (that is, deciding
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Approximate Minimization of Weighted Tree Automata Inf. Comput. (IF 0.872) Pub Date : 2020-11-13 Borja Balle; Guillaume Rabusseau
This paper studies the following approximate minimization problem: given a minimal weighted tree automaton A with n states recognizing a weighted tree language f, can we construct a smaller automaton Aˆ with nˆ
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Subject-oriented spatial logic Inf. Comput. (IF 0.872) Pub Date : 2020-11-01 Przemysław Andrzej Wałęga; Michał Zawidzki
We present a modal logic for subject-oriented representation and reasoning about a two-dimensional space. The space is represented with the polar coordinate system where the central point is occupied by the subject and modal operators are interpreted by relations defined relatively to the position and orientation of the subject, namely ‘outwards’, ‘inwards’, ‘clockwise’, ‘counter-clockwise’, and transitive
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Complexity analysis of a unifying algorithm for model checking Interval Temporal Logic Inf. Comput. (IF 0.872) Pub Date : 2020-11-01 Laura Bozzelli; Angelo Montanari; Adriano Peron
The model checking (MC) problem for Halpern and Shoham's interval temporal logic HS has been recently investigated in a systematic way, and it is known to be decidable. An intriguing open question is the exact complexity of the problem for full HS: it is at least EXPSPACE-hard, and the only known upper bound, which has been obtained by exploiting an abstract representation of Kripke structure paths
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Consistency Checking of STNs with Decisions: Managing Temporal and Access-Control Constraints in a Seamless Way Inf. Comput. (IF 0.872) Pub Date : 2020-11-01 Matteo Zavatteri; Carlo Combi; Romeo Rizzi; Luca Viganò
A Simple Temporal Network (STN) consists of time points modeling temporal events and constraints modeling the minimal and maximal temporal distance between them. A Simple Temporal Network with Decisions (STND) extends an STN by adding decision time points to model temporal plans with decisions. A decision time point is a special kind of time point that once executed allows for deciding a truth value
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Timed Hyperproperties Inf. Comput. (IF 0.872) Pub Date : 2020-11-01 Hsi-Ming Ho; Ruoyu Zhou; Timothy M. Jones
We study the satisfiability and model-checking problems for timed hyperproperties specified with HyperMITL, a timed extension of HyperLTL. While the satisfiability problem can be solved similarly as for HyperLTL, we show that the model-checking problem for HyperMITL, unless the specification is alternation-free, is undecidable even when very restricted timing constraints are allowed. On the positive
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On neighbourhood singleton-style consistencies for qualitative spatial and temporal reasoning Inf. Comput. (IF 0.872) Pub Date : 2020-11-01 Michael Sioutis; Anastasia Paparrizou; Tomi Janhunen
Given a qualitative constraint network (QCN), a singleton-style consistency is a local consistency that focuses on each base relation (atom) of a constraint separately, rather than the entire constraint altogether. More technically, such a consistency verifies if each base relation of each constraint of a QCN can serve as a support with respect to the closure of that network under a (naturally) weaker
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To Drive or Not to Drive: A Logical and Computational Analysis of European Transport Regulations Inf. Comput. (IF 0.872) Pub Date : 2020-11-01 Ana de Almeida Borges; Juan José Conejero Rodríguez; David Fernández-Duque; Mireia González Bedmar; Joost J. Joosten
This paper analyses a selection of articles from European transport regulations that contain algorithmic information, but may be problematic to implement. We focus on issues regarding the interpretation of tachograph data and requirements on weekly rest periods. We first show that the interpretation of data prescribed by these regulations is highly sensitive to minor variations in input, such that
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QCTL model-checking with QBF solvers Inf. Comput. (IF 0.872) Pub Date : 2020-10-31 Akash Hossain; François Laroussinie
Quantified CTL (QCTL) extends the temporal logic CTL with quantifications over atomic propositions. This extension is known to be very expressive: QCTL allows us to express complex properties over Kripke structures (it is as expressive as MSO). Several semantics exist for the quantifications: here, we work with the structure semantics, where the extra propositions label the Kripke structure (and not
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A decidable and expressive fragment of Many-Sorted First-Order Linear Temporal Logic Inf. Comput. (IF 0.872) Pub Date : 2020-10-30 Quentin Peyras; Julien Brunel; David Chemouil
First-Order Linear Temporal Logic (FOLTL) and its Many-Sorted variant (MSFOLTL) are well-suited to specify infinite-state systems. However, the satisfiability of (MS)FOLTL is not even semi-decidable, thus preventing automated verification. In this paper, we exhibit various fragments of increasing scope that provide a pertinent basis for the abstract specification of infinite-state systems. We show
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A structured view on weighted counting with relations to counting, quantum computation and applications Inf. Comput. (IF 0.872) Pub Date : 2020-08-24 Cassio P. de Campos; Georgios Stamoulis; Dennis Weyland
Weighted counting problems are a natural generalization of counting problems where a weight is associated with every computational path of polynomial-time non-deterministic Turing machines. The goal is to compute the sum of weights of all paths (instead of number of accepting paths). Useful properties and plenty of applications make them interesting. The definition captures even undecidable problems
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Efficient pattern matching in elastic-degenerate strings Inf. Comput. (IF 0.872) Pub Date : 2020-08-11 Costas S. Iliopoulos; Ritu Kundu; Solon P. Pissis
Motivated by applications in bioinformatics and image searching, in what follows, we study the classic pattern matching problem in the context of elastic-degenerate strings: the generalised notion of gapped strings. An elastic-degenerate string can been seen as an ordered collection of k strings interleaved by k−1 elastic-degenerate symbols, where each such elastic-degenerate symbol corresponds to
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Integrated encryption in dynamic arithmetic compression Inf. Comput. (IF 0.872) Pub Date : 2020-08-10 Shmuel T. Klein; Dana Shapira
A variant of adaptive arithmetic coding is proposed, adding cryptographic features to this classical compression method. The idea is to perform the updates of the frequency tables for characters of the underlying alphabet selectively, according to some randomly chosen secret key K. We give empirical evidence that with reasonably chosen parameters, the compression performance is not hurt, and discuss
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A derivational model of discontinuous parsing Inf. Comput. (IF 0.872) Pub Date : 2020-08-10 Mark-Jan Nederhof; Anssi Yli-Jyrä
The notion of latent-variable probabilistic context-free derivation of syntactic structures is enhanced to allow heads and unrestricted discontinuities. The chosen formalization covers both constituency parsing and dependency parsing. By the new framework, one obtains a probability distribution over the space of all discontinuous parses. This lends itself to intrinsic evaluation in terms of cross-entropy
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