bluuebunny/crossref_metadata_2025 huggingface dataset:
Pointwise polarization tensor bounds, and applications to voltage perturbations caused by thin inhomogeneities
Authors: Capdeboscq Yves , Vogelius Michael S.
Published: December 2024

The main result of this paper establishes optimal pointwise bounds for the polarization tensors that appear in representation formulae for the voltage perturbations caused by low volume fraction inhomogeneities. Furthermore it is demonstrated how these pointwise bounds may be used to derive a particularly simple version of the representation formulae in the case of thin inhomogeneities.
Stabilization of the wave equation with variable coefficients and boundary condition of memory type
Authors: Nicaise Serge , Pignotti Cristina
Published: December 2024

We consider the stabilization of the wave equation with space variable coefficients in a bounded region with a smooth boundary, subject to Dirichlet boundary conditions on one part of the boundary and linear or nonlinear dissipative boundary conditions of memory type on the remainder part of the boundary. Our stabilization results are mainly based on the use of differential geometry arguments, on the multiplier method and the introduction of suitable Lyapounov functionals.
Gevrey type solutions of nonlinear difference equations
Authors: Immink G.K.
Published: December 2024

We prove the existence of Gevrey type solutions for locally analytic, nonlinear difference equations possessing a formal solution that belongs to some (generalized) Gevrey class of divergent power series in z−1/p. We consider different types of domains: domains bounded by a curve with limiting directions −π/2 and π/2 (mod  π), and domains bounded by curves with the same limiting direction, viz. π/2 (mod  π), containing an unbounded part of the imaginary axis.
Convergence results for a semilinear problem and for a Stokes problem in a periodic geometry
Authors: Baillet Séverine , Henrot Antoine , Takahashi Takéo
Published: December 2024

In this paper, we study the asymptotic behavior of the solution of a semilinear problem and of a Stokes problem, with periodic data, when the size of the domain increases. In particular, we prove exponential convergence to the solution of the corresponding problem with periodic boundary conditions.
Homogenization of a nonlinear transport equation
Authors: Mellet A. , Vasseur A.
Published: December 2024

In this paper, we investigate the homogenization of a nonlinear kinetic equation modeling electron transport in semiconductors. We compute effective scattering coefficients for medium with periodic inhomogeneities.
On the cost of fast controls for thermoelastic plates
Authors: Miller Luc
Published: December 2024

This paper proves that any initial condition in the energy space for the system of thermoelastic plates without rotatory inertia on a smooth bounded domain with hinged mechanical boundary conditions and Dirichlet thermal boundary condition can be steered to zero by a square integrable input function, either mechanical or thermal, supported in arbitrarily small sub-domain and time interval [0,T]. As T tends to zero, for initial states with unit energy norm, the norm of this input function grows at most like exp (Cp/Tp) for any real p>1 and some Cp>0. These results are analogous to the optimal ones known for the heat flow and the proof uses the heat control strategy of Lebeau and Robbiano.
Scattering theory for the Schrödinger–improved Boussinesq system in two space dimensions
Authors: Shimomura Akihiro
Published: December 2024

In this paper, the scattering theory for the Schrödinger–improved Boussinesq system in two space dimensions is studied. The local Cauchy problem at infinite initial time of this system for given final data is considered, and the existence of a unique asymptotically free solution to this system is proved when the Schrödinger data is suitably small.
On the convergence of some products of Fourier integral operators
Authors: Le Rousseau Jérôme
Published: December 2024

An approximation Ansatz for the operator solution, U(z′,z), of a hyperbolic first-order pseudodifferential equation, ∂z+a(z,x,Dx) with Re(a)≥0, is constructed as the composition of global Fourier integral operators with complex phases. The symbol a(z,·) is assumed to have a regularity as low as Hölder, 𝒞0,α, with respect to the evolution parameter z. We prove a convergence result for the Ansatz to U(z′,z) in some Sobolev space as the number of operators in the composition goes to ∞, with a convergence of order α. We also study the consequences of some truncation approximations of the symbol a(z,·) in the construction of the Ansatz.
On a nonlinear discrete hyperbolic system
Authors: Luca Rodica
Published: December 2024

The existence, uniqueness and asymptotic behaviour of the solutions to a nonlinear discrete hyperbolic system supplemented with an extreme condition and initial data are investigated in a real Hilbert space.
Derivation and justification of the model of micropolar elastic shells from three-dimensional linearized micropolar elasticity
Authors: Aganović Ibrahim , Tambača Josip , Tutek Zvonimir
Published: December 2024

In this paper we derive a two-dimensional model of elastic shell-like body from the three-dimensional linearized micropolar elasticity. Derivation is based on the asymptotic expansion method with respect to the thickness of the shell. The method is used without any a priori assumption on the scaling of the unknowns. The leading term, displacement and microrotation, is identified as the unique solution of a certain two-dimensional problem well defined for W1,∞ shells. Appropriate convergence results are proved.
Global Strichartz estimates for approximations of the Schrödinger equation
Authors: Ignat Liviu I.
Published: December 2024

We consider a semidiscrete scheme for the linear Schrödinger equation with high order dissipative term. We obtain maximum norm estimates for its solutions and we prove global Strichartz estimates for the considered model, estimates that are uniform with respect to the mesh size. The methods we employ are based on classical arguments of harmonic analysis.
Asymptotic behavior of elliptic problems in perforated domains with nonlinear boundary conditions
Authors: Cioranescu Doina , Donato Patrizia , Zaki Rachad
Published: December 2024

In this paper, we apply the periodic unfolding method in perforated domains introduced by Cioranescu et al. (Portugal. Math. 63(4) (2006), 467–496) to a class of elliptic problems with nonlinear conditions on the boundary of the holes. A new compactness result will play a major role in the homogenization process and provides correctors without using any extension operator.
New examples of damped wave equations with gradient-like structure
Authors: Joly Romain
Published: December 2024

This article shows how to use perturbation methods to get new examples of evolutionary partial differential equations with gradient-like structure. In particular, we investigate the case of the wave equation with a variable damping satisfying the geometric control condition only, and the case of the wave equation with a damping of indefinite sign.
Error estimates for periodic homogenization with non-smooth coefficients
Authors: Onofrei D. , Vernescu B.
Published: December 2024

In this paper we present new results regarding the H10-norm error estimate for the classical problem in homogenization using suitable boundary layer correctors. Compared with all the existing results on the subject, which assume either smooth enough coefficients or smooth data, we use the periodic unfolding method and propose a new asymptotic series to approximate the solution uε with an error estimate which holds true for nonsmooth coefficients and general data.
Exponential stability of a repairable system with imperfect switching mechanism
Authors: Hu Weiwei , Shen Zifei , Xin Yuhong , Zhu Guangtian
Published: December 2024

This paper is devoted to investigating the exponential stability of a kind of repairable system with cold standby units, imperfect switching mechanism and multiple non-critical and critical errors. We have known that the system operator generates a positive C0-semigroup of contractions and will show its quasi-compactness and irreducibility. Further, 0 is a simple eigenvalue of the system operator. As a result, we obtain that the time-dependent solution of the system converges to the steady-state solution exponentially, which is the positive eigenfunction corresponding to the simple eigenvalue 0.
Weighted coercive estimates of solutions to the Stokes problem in parabolically growing layer
Authors: Pileckas K. , Zaleskis L.
Published: December 2024

The Stokes problem is studied in the domain Ω⊂R3 coinciding outside the ball BR={x∈R3: |x|<R} with the parabolically growing layer Ω={x∈R3: x′=(x1, x2)∈R2, |x3|0 ∀x′∈R2 and h(x′)=|x′|β≡rβ, β∈(0, 1), for r>1. Coercive estimates of the solution to the Stokes problem are proved in a scale of weighted function spaces with the norm determined by a stepwise anisotropic distribution of weight factors.
Attractors for the semiflow associated with a class of doubly nonlinear parabolic equations
Authors: Schimperna Giulio , Segatti Antonio
Published: December 2024

We address a parabolic equation of the form α(ut)−Δu+W′(u)=f, complemented with initial and either Dirichlet or Neumann homogeneous boundary conditions. The “double nonlinearity” is due to the simultaneous presence of the maximal monotone function α and of the derivative W′ of a smooth, but possibly nonconvex, potential W; f is a source term. After recalling an existence result for weak solutions, we show that, among all the weak solutions, at least one for each admissible choice of the initial datum “regularizes” for t>0. Moreover, the class of “regularizing” solutions constitutes a semiflow 𝒮 for which we prove unique continuation for strictly positive times. Finally, we address the long time behavior of 𝒮. In particular, we can prove existence of both global and exponential attractors and investigate the structure of ω-limits of single trajectories.
On the large time behavior of a phase-field system with memory
Authors: Grasselli Maurizio
Published: December 2024

We consider a nonconserved phase-field model of Caginalp type which has been proposed by H.G. Rotstein et al. This model consists of two coupled integro-partial differential equations, one for the temperature ϑ, the other for the order parameter χ, and each one is characterized by a nonnegative decreasing memory kernel. Such equations, endowed with homogeneous Dirichlet (for ϑ) and Neumann (for χ) boundary conditions, generate a dissipative dynamical system which possesses a global attractor 𝒜. This fact was proven by V. Pata and the author. Here we construct a compact exponentially attracting set which, in particular, entails a smoothness result for 𝒜. Then we also demonstrate the convergence of any trajectory to a single equilibrium, via the Łojasiewicz–Simon approach.
A lower bound for the life span of solutions to relativistic Vlasov–Maxwell systems
Authors: Pallard Christophe
Published: December 2024

We show that the time of existence of classical solutions to the relativistic Vlasov–Maxwell system generated by fixed initial data tends to infinity as the speed of light becomes infinite.
Interactive Knapsacks
Authors: Aho Isto
Published: December 2024

The interactive knapsack problems are generalizations of the classical knapsack problem. Three different new NP-complete problems, interactive knapsack heuristic decision problem (IKHD), interactive knapsack decision problem (IKD) and multidimensional cloned knapsack decision problem (MDCS), are presented for the interactive knapsack models. IKD and MDCS are shown to be strongly NP-complete. By using interactive knapsacks we can model many planning and scheduling problems in an innovative way. Possible application areas include electricity management, single and multiprocessor scheduling, and packing and tiling problems. As a by-product we show that the longest weight-constrained path problem is NP-complete.
On a Construction of Context-free Grammars
Authors: Martinek Pavel
Published: December 2024

The grammatical inference problem is solved for the class of context-free languages. A context-free language is supposed to be given by means of all its strings. Considering all strings of length bounded by k, context-free grammars G_{j,k} with 1≤j<k are constructed. A~continual increasing of the index~$k$ leads to an~infinite sequence (G_{j,k})_{j<k}. It is proved that G_{j,k} are equivalent for all j≥j_0, k≥k_0 with some positive integers j_0, k_0. Moreover, the equivalences among these grammars can be recognized on the basis of involved nonterminals and productions only.
From Mirkin's Prebases to Antimirov's Word Partial	Derivatives
Authors: Champarnaud Jean-Marc , Ziadi Djelloul
Published: December 2024

Our aim is to give a proof of the fact that two notions related to regular expressions, the prebases due to Mirkin and the partial derivatives introduced by Antimirov lead to the construction of identical nondeterministic automata recognizing the language of a given regular expression.
Process Algebras for Network Communication
Authors: Gruska Damas P. , Maggiolo-Schettini Andrea
Published: December 2024

Critical issues that arise when process algebras are used for protocol specifications are discussed. To overcome some of these problems, a process algebra for protocol specifications is presented. It is based on Milner's Calculus of Communicating Systems, which is enriched by time and network reasoning. Several bisimulation based semantics for the calculus are defined and their properties are discussed.
Complexity Results for 2CNF Default Theories
Authors: Zhao Xishun , Ding Decheng
Published: December 2024

This paper is concerned with the complexity of default reasoning with 2CNF default theories (D,W) in which W is a set of literals and D is a set of 2CNF defaults. It is proved that the problem whether a literal occurs in at least one extension can be solved in polynomial time. But the problem whether a literal appears in all extensions is proved to be co-NP-complete. The complexity of some subclasses of 2CNF default theories is also analyzed.
Algorithms and Reductions for Rewriting Problems
Authors: Verma Rakesh M. , Rusinowitch Michael , Lugiez Denis
Published: December 2024

In this paper we initiate a study of polynomial-time reductions for some basic decision problems of rewrite systems. We then give a polynomial-time algorithm for the unique-normal-form property of ground systems for the first time. Next we prove undecidability of several problems for a fixed string rewriting system using our reductions. Finally, we prove the decidability of confluence for commutative semi-thue systems. The Confluence and Unique-normal-form property are shown Expspace-hard for commutative semi-thue systems. We also show that there is a family of string rewrite systems for which the word problem is trivially decidable but confluence is undecidable, and we show a linear equational theory with decidable word problem but undecidable linear equational matching problem.
Relaxed Update and Partition Network Games
Authors: Bodlaender Hans L. , Dinneen Michael J. , Khoussainov Bakhadyr
Published: December 2024

In this paper, we study the complexity of deciding which player has a winning strategy in certain types of McNaughton games. These graph games can be used as models for computational problems and processes of infinite duration. We consider the cases (1) where the first player wins when vertices in a specified set are visited infinitely often and vertices in another specified set are visited finitely often, (2) where the first player wins when exactly those vertices in one of a number of specified disjoint sets are visited infinitely often, and (3) a generalization of these first two cases. We give polynomial time algorithms to determine which player has a winning strategy in each of the games considered.
Processing Indefinite Deductive Databases under the Possible Model	Semantics
Authors: Johnson C.A.
Published: December 2024

The relationship between possible and supported models of unstratified indefinite deductive databases is studied, when disjunction is interpreted inclusively. Possible and supported models are shown to coincide under a suitable definition of supportedness, and the concept of a supported cover is introduced and shown to characterise possible models and facilitate top-down query processing and compilation under the possible model semantics. The properties and query processing of deductive databases under the possible model semantics is compared and contrasted with the perfect model semantics.
A New Bayesian Tree Learning Method with Reduced Time and Space	Complexity
Authors: Kłopotek Mieczysław Alojzy
Published: December 2024

Bayesian networks have many practical applications due to their capability to represent joint probability distribution in many variables in a compact way. There exist efficient reasoning methods for Bayesian networks. Many algorithms for learning Bayesian networks from empirical data have been developed. A well-known problem with Bayesian networks is the practical limitation for the number of variables for which a Bayesian network can be learned in reasonable time. A remarkable exception here is the Chow/Liu algorithm for learning tree-like Bayesian networks. However, its quadratic time and space complexity in the number of variables may prove also prohibitive for high dimensional data. The paper presents a novel algorithm overcoming this limitation for the tree-like class of Bayesian networks. The new algorithm space consumption grows linearly with the number of variables n while the execution time is proportional to n·ln(n), hence both are better than those of Chow/Liu algorithm. This opens new perspectives in construction of Bayesian networks from data containing tens of thousands and more variables, e.g. in automatic text categorization.
UPSILON: Universal Programming System with Incomplete Lazy Object	Notation
Authors: Postow Brian , Regan Kenneth , Smith Carl H.
Published: December 2024

This paper presents a new model of computation that differs from prior models in that it emphasizes data over flow control, has no named variables and has an object-oriented flavor. We prove that this model is a complete and confluent acceptable programming system and has a usable type theory. A new data synchronization primitive is introduced in order to achieve the above properties. Subtle variations of the model are shown to fall short of having all these necessary properties.
Weaker Axioms, More Ranges
Authors: Koutras Costas D. , Pappas Pavlos
Published: December 2024

In the family of many-valued modal languages proposed by M. Fitting in 1992, every modal language is based on an underlying Heyting algebra which provides the space of truth values. The lattice of truth values is explicitly represented in the language by a set of special constants and this allows for forming weak, generalized, many-valued analogs of all classical modal axioms. Weak axioms of this kind have been recently investigated from the canonicity, completeness and correspondence perspective. In this paper, we provide some results on the effect of adopting weak versions of the axioms D, T, 4, 5 and w5 in the family of many-valued modal non-monotonic logics, à la McDermott and Doyle, introduced in [4] and further investigated in [7]. For many-valued modal languages built on finite chains, we extend the results of [7] by proving two quite general range theorems. We then hint on the relation between the modal non-monotonic logics obtained: we prove that there exist ranges which selectively pick out some of the expansions produced by the many-valued autoepistemic logics introduced in [4,9], actually the ones with a confidence-bounded set of beliefs. However, an exact characterization of the relation between the various ranges created by the weak many-valued modal axioms still remains to be explored.
RIONA: A New Classification System Combining Rule Induction and	Instance-Based Learning
Authors: Góra Grzegorz , Wojna Arkadiusz
Published: December 2024

The article describes a method combining two widely-used empirical approaches to learning from examples: rule induction and instance-based learning. In our algorithm (RIONA) decision is predicted not on the basis of the whole support set of all rules matching a test case, but the support set restricted to a neighbourhood of a test case. The size of the optimal neighbourhood is automatically induced during the learning phase. The empirical study shows the interesting fact that it is enough to consider a small neighbourhood to achieve classification accuracy comparable to an algorithm considering the whole learning set. The combination of k-NN and a rule-based algorithm results in a significant acceleration of the algorithm using all minimal rules. Moreover, the presented classifier has high accuracy for both kinds of domains: more suitable for k-NN classifiers and more suitable for rule based classifiers.
On Modal and Fuzzy Decision Logics Based on Rough Set Theory
Authors: Fan Tuan-Fang , Liau Churn-Jung , Yao Yiyu
Published: December 2024

Some modal decision logic languages are proposed for knowledge representation in data mining through the notions of models and satisfiability. The models are collections of data tables consisting of a finite set of objects described by a finite set of attributes. Some relationships may exist between data tables in a collection and the modalities of our languages are interpreted with respect to these relations in Kripkean style semantics. The notion of fuzzy decision logic is also reviewed and combined with the modal decision logic. The combined logic is shown to be useful in the representation of fuzzy sequential patterns.
One-Visit Caterpillar Tree Automata
Authors: Okhotin Alexander , Salomaa Kai , Domaratzki Michael
Published: December 2024

We study caterpillar tree automata [3] that are restricted to enter any subtree at most one time (or k times). We show that, somewhat surprisingly, the deterministic one-visit automata can already, for instance, evaluate trees where the nodes represent some non-associative operations. We show that there exist regular tree languages that cannot be accepted by a one-visit automaton, thus proving a weakened form of a conjecture of Brüggemann-Klein and Wood [3]. We establish that the k-visit property is decidable.
A Logical Approach to Control. Some New Logical Concepts and	their Application to the Notion of Safety for Control Variants
Authors: Terlikowski Tomasz
Published: December 2024

In this paper, we introduce logical notions of positive implication and positive correspondence aimed at a formalization of notions of safety of control variants in control theory.
On message deliverability and non-uniform receptivity
Authors: Amadio Roberto , Boudol Gerard , Lhoussaine Cedric
Published: December 2024

The message deliverability property requires that every emitted message has a chance of being received. In the context of the asynchronous π-calculus, we introduce a discipline of non-uniform receptivity that entails this property. Adopting this discipline requires a style of programming where resources are persistent. We give a general method to transform (in a fully abstract way) a process so that it complies with the discipline.
Learning Rough Set Classifiers from Gene Expressions and Clinical	Data
Authors: Midelfart Herman , Komorowski Jan , Nørsett Kristin , Yadetie Fekadu , Sandovik Arne K. , Lægreid Astrid
Published: December 2024

Biological research is currently undergoing a revolution. With the advent of microarray technology the behavior of thousands of genes can be measured simultaneously. This capability opens a wide range of research opportunities in biology, but the technology generates a vast amount of data that cannot be handled manually. Computational analysis is thus a prerequisite for the success of this technology, and research and development of computational tools for microarray analysis are of great importance. One application of microarray technology is cancer studies where supervised learning may be used for predicting tumor subtypes and clinical parameters. We present a general Rough Set approach for classification of tumor samples analyzed with microarrays. This approach is tested on a data set of gastric tumors, and we develop classifiers for six clinical parameters. One major obstacle in training classifiers from microarray data is that the number of objects is much smaller that the number of attributes. We therefore introduce a feature selection method based on bootstrapping for selecting genes that discriminate significantly between the classes, and study the performance of this method. Moreover, the efficacy of several learning and discretization methods implemented in the ROSETTA system [18] is examined. Their performance is compared to that of linear and quadratic discrimination analysis. The classifiers are also biologically validated. One of the best classifiers is selected for each clinical parameter, and the connection between the genes used in these classifiers and the parameters are compared to the establish knowledge in the biomedical literature.
New polynomial-time instances to various knapsack-type	problems
Authors: Aho Isto
Published: December 2024

We describe a special case of the interactive knapsack optimization problem (motivated by the load clipping problem) solvable in polynomial time. Given an instance parameterized by k, the solution can be found in polynomial time, where the polynomial has degree k. In the interactive knapsack problem, $k$ is connected to the length induced by an item. A similar construction solves a special case of the 0–1 multi-dimensional knapsack and the 0–1 linear integer programming problems in polynomial time. In these problems the parameter determines the width of the restriction matrix, which is a band matrix. We extend the 0–1 multi-dimensional knapsack solution to 0–n multi-dimensional knapsack problems (and to 0–n IP problems). Our algorithms are based on the (resource bounded) shortest path search: we represent restrictions efficiently in a form of a graph such that each feasible solution has a path between given source and target vertices.
A new class of algebraic series having a decidable equivalence	problem
Authors: Honkala Juha
Published: December 2024

We introduce a new class of algebraic series with noncommuting variables having a decidable equivalence problem. As a tool we consider star roots of formal power series.
Relating Communicating Processes with Different Interfaces
Authors: Burton Jonathan , Koutny Maciej , Pappalardo Giuseppe
Published: December 2024

We present here an implementation relation intended to formalise the notion that a system built of communicating processes is an acceptable implementation of another base, or target, system in the event that the two systems have different interfaces. Such a treatment has clear applicability in the software development process, where (the interface of) an implementation component may be expressed at a different level of abstraction to (the interface of) the relevant specification component. Technically, processes are formalised using Hoare's CSP language, with its standard failures-divergences model. The implementation relation is formulated in terms of failures and divergences of the implementation and target processes. Interface difference is modelled by endowing the implementation relation with parameters called extraction patterns. These are intended to interpret implementation behaviour as target behaviour, and suitably constrain the former in connection to well-formedness and deadlock properties. We extend the results of our previous work and replace implementation relations previously presented by a single, improved scheme. We also remove all the restrictions previously placed upon target processes. Two basic kinds of results are obtained: realisability and compositionality. The latter means that a target composed of several connected systems may be implemented by connecting their respective implementations. The former means that, if target and implementation in fact have the same interface, then the implementation relation they should satisfy collapses into standard implementation pre-order. We also show how to represent processes and extraction patterns in a manner amenable to computer implementation, and detail a graph-theoretic restatement of the conditions defining the implementation relation, from which algorithms for their automatic verification are easily derived.
Error-Robust Functional Dependencies
Authors: Hartmann Sven , Link Sebastian , Schewe Klaus-Dieter , Thalheim Bernhard
Published: December 2024

A database user may be confronted with a relation that contains errors. These errors may result from transmission through a noisy channel, or they may have been added deliberately in order to hide or spoil information. Error-robust functional dependencies provide dependencies that still hold in the case of errors. The paper investigates the finite axiomatisation of such dependencies. It presents a sound and complete system of axioms and rules for the implication of error-robust dependencies including disjunctions.
Asymptotics for Length and Trajectory from Cumulative Chord Piecewise-Quartics
Authors: Kozera Ryszard
Published: December 2024

We discuss the problem of estimating the trajectory of a regular curve γ:[0,T]→Rn and its length d(γ) from an ordered sample of interpolation points Qm={γ(t0),γ(t1),...,γ(tm)}, with tabular points ti's unknown, coined as interpolation of unparameterized data. The respective convergence orders for estimating γ and d(γ) with cumulative chord piecewise-quartics are established for different types of unparameterized data including egr-uniform and more-or-less uniform samplings. The latter extends previous results on cumulative chord piecewise-quadratics and piecewise-cubics. As shown herein, further acceleration on convergence orders with cumulative chord piecewise-quartics is achievable only for special samplings (e.g. for ε-uniform samplings). On the other hand, convergence rates for more-or-less uniform samplings coincide with those already established for cumulative chord piecewise-cubics. The results are experimentally confirmed to be sharp for m large and n=2,3. A good performance of cumulative chord piecewise-quartics extends also to sporadic data (m small) for which our asymptotical analysis does not apply directly.
Image Indexing by Distributed Color Temperature Descriptions
Authors: Wnukowicz Karol
Published: December 2024

The paper presents new methods for image content indexing by the use of color temperature feature. A descriptor for dominant color temperature is introduced, for which two types of queries are discussed: a query by color temperature value and a query by example. Finally, a data structure for search optimized storage of the introduced descriptor is proposed and evaluated.
A Rough Set Theoretic Approach to Clustering
Authors: De Supriya Kumar
Published: December 2024

In this paper, cluster analysis based on fuzzy relations is investigated. This paper starts with fuzzy proximity relations and cluster analysis based on fuzzy proximity relation is performed by using rough approximation. A clustering algorithm has been proposed and explained with an example.
R. Thomas' Modeling of Biological Regulatory Networks:	Introduction of Singular States in the Qualitative Dynamics
Authors: Richard Adrien , Comet Jean-Paul , Bernot Gilles
Published: December 2024

In the field of biological regulation, models extracted from experimental works are usually complex networks comprising intertwined feedback circuits. The overall behavior is difficult to grasp and the development of formal methods is needed in order to model and simulate biological regulatory networks. To model the behavior of such systems, R. Thomas and coworkers developed a qualitative approach in which the dynamics is described by a state transition system. Even if all steady states of the system can be detected in this formalism, some of them, the singular ones, are not formally included in the transition system. Consequently, temporal properties in which singular states have to be described, cannot be checked against the transition system. However, steady singular states play an essential role in the dynamics since they can induce homeostasis or multistationnarity and sometimes are associated to biological phenotypes.

These observations motivated our interest for developing an extension of Thomas formalism in which all singular states are represented, allowing us to check temporal properties concerning singular states. We easily demonstrate in our formalism the previously demonstrated theorems giving the conditions for the steadiness of singular states. We also prove that our formalism is coherent with the Thomas one since all paths of the Thomas transition system are preserved in our one, which in addition includes singular states.
Synchronous and Asynchronous Communications in Composable	Parameterized High-Level Petri Nets
Authors: Devillers Raymond , Klaudel Hanna
Published: December 2024

In the domain of parameterized composable high-level Petri nets (M-nets), we shall combine the refinement, the synchronization and the asynchronous link operations in a unified and general setup, while keeping the expected properties of those operations. In particular, the various high-level net operations are consistent through unfolding with their low-level counterparts, and the usual commutativity and idempotency properties are fulfilled at the syntactic level up to structural equivalences.
KDS-transformation for Data Compression
Authors: Popa Ionuţ
Published: December 2024

In this paper we present a new simple method to rewrite a given input string into another one which can be more efficiently compressed (in some cases) by traditional compression methods.
$-Calculus of Bounded Rational Agents: Flexible Optimization as	Search under Bounded Resources in Interactive Systems
Authors: Eberbach Eugene
Published: December 2024

This paper presents a novel model for resource bounded computation based on process algebras. Such model is called the $-calculus (cost calculus). Resource bounded computation attempts to find the best answer possible given operational constraints. The $-calculus provides a uniform representation for optimization in the presence of limited resources. It uses cost-optimization to find the best quality solutions while using a minimal amount of resources.

A unique aspect of the approach is to propose a resource bounded process algebra as a generic problem solving paradigm targeting interactive AI applications. The goal of the $-calculus is to propose a computational model with built-in performance measure as its central element. This measure allows not only the expression of solutions, but also provides the means to incrementally construct solutions for computationally hard, real-life problems. This is a dramatic contrast with other models like Turing machines, λ-calculus, or conventional process algebras. This highly expressive model must therefore be able to express approximate solutions.

This paper describes the syntax and operational cost semantics of the calculus. A standard cost function has been defined for strongly and weakly congruent cost expressions. Example optimization problems are given which take into account the incomplete knowledge and the amount of resources used by an agent. The contributions of the paper are twofold: firstly, some necessary conditions for achieving global optimization by performing local optimization in time and/or space are found.

That deals with incomplete information and complexity during problem solving. Secondly, developing an algebra which expresses current practices, e.g., neural nets, cellular automata, dynamic programming, evolutionary computation, or mobile robotics as limiting cases, provides a tool for exploring the theoretical underpinnings of these methods. As the result, hybrid methods can be naturally expressed and developed using the algebra.
Regular Expressions for Languages over Infinite Alphabets
Authors: Kaminski Michael , Tan Tony
Published: December 2024

In this paper we introduce a notion of a regular expression over infinite alphabets and show that a language is definable by an infinite alphabet regular expression if and only if it is accepted by finite-state unification based automaton – a model of computation that is tightly related to other models of automata over infinite alphabets.
Multistrategy Operators for Relational Learning and Their	Cooperation
Authors: Esposito Floriana , Fanizzi Nicola , Ferilli Stefano , Basile Teresa M.A. , Di Mauro Nicola
Published: December 2024

Traditional Machine Learning approaches based on single inference mechanisms have reached their limits. This causes the need for a framework that integrates approaches based on abduction and abstraction capabilities in the inductive learning paradigm, in the light of Michalski's Inferential Theory of Learning (ITL). This work is intended as a survey of the most significant contributions that are present in the literature, concerning single reasoning strategies and practical ways for bringing them together and making them cooperate in order to improve the effectiveness and efficiency of the learning process. The elicited role of an abductive proof procedure is tackling the problem of incomplete relevance in the incoming examples. Moreover, the employment of abstraction operators based on (direct and inverse) resolution to reduce the complexity of the learning problem is discussed. Lastly, a case study that implements the combined framework into a real multistrategy learning system is briefly presented.
Counter-Free Keys and Functional Dependencies in Higher-Order	Datamodels
Authors: Sali Attila , Schewe Klaus-Dieter
Published: December 2024

We investigate functional dependencies (FDs) in the presence of several constructors for complex values. These constructors are the tuple constructor, list-, set- and multiset-constructors, an optionality constructor, and a disjoint union constructor. The disjoint union constructor implies restructuring rules, which complicate the theory. In particular, they do not permit a straightforward axiomatisation of the class of all FDs without a detour via weak functional dependencies (wFDs), i.e. disjunctions of functional dependencies, and even the axiomatisation of wFDs is not yet completely solved.

Therefore, we look at the restricted class of counter-free functional dependencies (cfFDs). That is, we ignore subattributes that only refer to counting the number of elements in sets or multisets or distinguish only between empty or non-empty sets. We present a finite axiomatisation for the class of cfFDs.

Furthermore, we study keys ignoring again the counting subattributes. We show that such keys are equivalent with certain ideals called HL-ideals. Based on that we introduce an ordering between key sets, and investigate systems of minimal keys. We give a sufficient condition for a Sperner family of HL-ideals being a system of minimal keys, and determine lower and upper bounds for the size of the smallest Armstrong-instance.
Indexing Schemes for Similarity Search: an Illustrated	Paradigm
Authors: Pestov Vladimir , Stojmirović Aleksandar
Published: December 2024

We suggest a variation of the Hellerstein – Koutsoupias – Papadimitriou indexability model for datasets equipped with a similarity measure, with the aim of better understanding the structure of indexing schemes for similarity-based search and the geometry of similarity workloads. This in particular provides a unified approach to a great variety of schemes used to index into metric spaces and facilitates their transfer to more general similarity measures such as quasi-metrics. We discuss links between performance of indexing schemes and high-dimensional geometry. The concepts and results are illustrated on a very large concrete dataset of peptide fragments equipped with a biologically significant similarity measure.
Resource-Constrained Workflow Nets
Authors: van Hee Kees , Sidorova Natalia , Voorhoeve Marc
Published: December 2024

We study concurrent processes modelled as workflow Petri nets extended with resource constrains. Resources are durable units that can be neither created nor destroyed: they are claimed during the handling procedure and then released again. Typical kinds of resources are manpower, machinery, computer memory. We define structural criteria based on traps and siphons for the correctness of workflow nets with resource constraints. We also extend the soundness notion for workflow nets to the workflow nets with resource constraints; extra conditions concern the durability of resources. We prove some properties of sound resource-constrained workflow nets.
A Value-propagating Transformation Technique for Datalog Programs	Based on Non-Deterministic Constructs
Authors: Potikas Petros , Rondogiannis Panos , Gergatsoulis Manolis
Published: December 2024

The branching-time transformation is a recent technique for optimizing Chain Datalog programs. In this paper we propose a significant extension of the branching-time transformation which we believe opens up a promising new direction of research in the area of value-propagating Datalog optimizations. More specifically, the proposed transformation can handle more general programs that allow multiple consumptive occurrences of variables in the bodies of clauses. This extension is achieved by using as target language the temporal logic programming formalism Datalog _{nS} enriched with choice predicates (a non-deterministic construct that was originally introduced in the area of intensional logic programming). We demonstrate the correctness of the transformation and propose several optimizations that can be applied to the target code. Moreover, we define a bottom-up proof procedure that applies to the target programs and demonstrate that it always terminates (despite the fact that the Herbrand base of these programs is generally infinite).
Model-Based Feature Compensation for Robust Speech	Recognition
Authors: Shen Haifeng , Li Qunxia , Guo Jun , Liu Gang
Published: December 2024

This paper proposes a novel robust speech recognition approach based on the model-based feature compensation. The approach combines the GMM-based feature compensation and the HMM-based feature compensation together and employs the multiple recognition passes to achieve the best performance. In the initial recognition procedure, the GMM-based feature compensation approach is employed to give better clean model and noise model. Then we further refine these models by employing the HMM-based feature compensation approach. The statistical model of the clean speech and the noise is combined by using vector Taylor series (VTS) approximation. The experimental results show that the novel approach makes a significant improvement compared to the GMM-based feature compensation and the HMM-based feature compensation without any compensation in the initial pass.
Reversible Data Embedding Based on Prediction Approach for VQ and	SMVQ Compressed Images
Authors: Chang Chin-Chen , Lin Chih-Yang
Published: December 2024

Reversible steganography allows an original image that has gone through the embedding process to be completely restored after the extraction of the embedded data. In this paper, we propose a reversible scheme with a high embedding capacity for VQ compressed images. Our reversible method is based on a prediction strategy and takes advantage of the local characteristics of the image. Since the location map is usually a necessary part of a reversible scheme, two methods, shifting and relocating, are also proposed to reduce the size of the location map. As the experimental results show later, our method outperforms previous schemes in terms of embedding capacity and image quality. To be more specific, with low distortion, the embedding capacity of the proposed methods can be higher than one bit per index value.
Contact Algebras and Region-based Theory of Space: A Proximity	Approach – I
Authors: Dimov Georgi , Vakarelov Dimiter
Published: December 2024

This work is in the field of region-based (or Whitehedian) theory of space, which is an important subfield of Qualitative Spatial Reasoning (QSR). The paper can be considered also as an application of abstract algebra and topology to some problems arising and motivated in Theoretical Computer Science and QSR.

Different axiomatizations for region-based (or Whiteheadian) theory of space are given. The most general one is introduced under the name "Contact Algebra" Adding some extra first- or secondorder axioms to those of contact algebras, some new or already known algebraic notions are obtained. Representation theorems and completion theorems for all such algebras are proved. Extension theories of the classes of all semiregular T _0 -spaces and all N-regular (a notion introduced here) T _1 -spaces are developed.
Contact Algebras and Region-based Theory of Space: Proximity	Approach – II
Authors: Dimov Georgi , Vakarelov Dimiter
Published: December 2024

This paper is the second part of the paper [2]. Both of themare in the field of region-based (or Whitehedian) theory of space, which is an important subfield of Qualitative Spatial Reasoning (QSR). The paper can be considered also as an application of abstract algebra and topology to some problems arising and motivated in Theoretical Computer Science and QSR. In [2], different axiomatizations for region-based theory of space were given. The most general one was introduced under the name "Contact Algebra". In this paper some categories defined in the language of contact algebras are introduced. It is shown that they are equivalent to the category of all semiregular T _0 -spaces and their continuous maps and to its full subcategories having as objects all regular (respectively, completely regular; compact; locally compact) Hausdorff spaces. An algorithm for a direct construction of all, up to homeomorphism, finite semiregular T _0 -spaces of rank n is found. An example of an RCC model which has no regular Hausdorff representation space is presented. The main method of investigation in both parts is a lattice-theoretic generalization of methods and constructions from the theory of proximity spaces. Proximity models for various kinds of contact algebras are given here. In this way, the paper can be regarded as a full realization of the proximity approach to the region-based theory of space.
Modal-Like Operators in Boolean Lattices, Galois Connections and	Fixed Points
Authors: Järvinen Jouni , Kondo Michiro , Kortelainen Jari
Published: December 2024

In this work, four modal-like operators on Boolean lattices are introduced and their theory is presented from lattice-theoretical, topological and algebraic point of view. It is also shown how rough set approximation operators, modal operators in temporal logic, and linguistic modifiers determined by L-sets can be interpreted as modal-like operators.
Secret Image Hiding and Sharing Based on the (t,n)-Threshold
Authors: Chang Chin-Chen , Lin Chih-Yang , Tseng Chun-Sen
Published: December 2024

This study proposes a new secret image sharing method based on the (t,n)-threshold. The sharing method is completed through three main steps: (1) quantizing the secret image, (2) generating n shadows from the quantized image, and (3) sharing the n shadows among n cover images. Our goal is both to attain good stego-image and secret image quality preservation effects and to limit the size of each shadow image down to 1/t of that of the secret image for convenient transmission and storage. In the first step, the secret image is divided into non-overlapping 4 × 4 blocks that are quantized according to the results of block testing. Each block, after the block testing procedure, is judged to be either a smooth block or a non-smooth one. Smooth blocks can be neatly restored after being hidden into the cover image, while non-smooth blocks can be somewhat lossy, but such modification is perceptually invisible. The second step is to apply Shamir's (t,n)-threshold, which uses a (t−1)-degree polynomial to generate n shadows so that the secret image can be restored from any t out of n shadows. The last step involves a modulo operation to hide the n shadows in n cover images. According to our experimental results, the PSNR values of the reconstructed secret images by our method center around 39 dB, outperforming other recent methods.