Fundamenta Informaticae - Volume 90, issue 1-2

Authors: Champarnaud, Jean-Marc | Ouardi, Faissal | Ziadi, Djelloul

Article Type: Research Article

Abstract: The aim of this paper is to describe a quadratic algorithm for computing the equation K-automaton of a regular K-expression as defined by Lombardy and Sakarovitch. Our construction is based on an extension to regular K-expressions of the notion of c-continuation that we introduced to compute the equation automaton of a regular expression as a quotient of its position automaton.

Keywords: regular K-expression, K-automaton, equation K-automaton, c-continuation

DOI: 10.3233/FI-2009-0001

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 1-16, 2009

Authors: Chang, Chin-Chen | Chou, Yung-Chen

Article Type: Research Article

Abstract: Image authentication is an important research topic of maintaining the integrity of digital image contents. Fragile image authentication is the technique for achieving the goal of image content integrity maintenance. This article presents a fragile image authentication scheme based on the concept of wet paper codes. The proposed scheme modifies dry pixels on an image to conceal an image signature. The proposed authentication scheme can exactly detect the tampered area on a tampered image. For saving …computation cost of signature embedding, an exclusive-or operation is used in the proposed authentication scheme. The experimental results show that the proposedmethod not only has good visual quality of an authorized image but also successfully detects tampered areas on a tampered image. Show more

Keywords: Data hiding, image authentication, signature, wet paper codes

DOI: 10.3233/FI-2009-0002

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 17-26, 2009

Authors: Cīrulis, Jānis

Article Type: Research Article

Abstract: Study of the so called knowledge ordering of rough sets was initiated by V.W. Marek and M. Truszczynski at the end of 90-ies. Under this ordering, the rough sets of a fixed approximation space form a domain in which every set ↓ is a Boolean algebra. In the paper, an additional operation inversion on rough set domains is introduced and an abstract axiomatic description of obtained algebras of rough set is given. It is shown that the …resulting class of algebras is essentially different from those traditional in rough set theory: it is not definable, for instance, in the class of regular double Stone algebras, and conversely. Show more

Keywords: description domain, double Stone algebra, inversion, knowledge ordering, rough set, semi-Boolean domain

DOI: 10.3233/FI-2009-0003

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 27-41, 2009

Authors: Ferilli, S. | Basile, T.M.A. | Biba, M. | Di Mauro, N. | Esposito, F.

Article Type: Research Article

Abstract: First-Order Logic formulæ are a powerful representation formalism characterized by the use of relations, that cause serious computational problems due to the phenomenon of indeterminacy (various portions of one description are possibly mapped in different ways onto another description). Being able to identify the correct corresponding parts of two descriptions would help to tackle the problem: hence, the need for a framework for the comparison and similarity assessment. This could have many applications in …Artificial Intelligence: guiding subsumption procedures and theory revision systems, implementing flexible matching, supporting instance-based learning and conceptual clustering. Unfortunately, few works on this subject are available in the literature. This paper focuses on Horn clauses, which are the basis for the Logic Programming paradigm, and proposes a novel similarity formula and evaluation criteria for identifying the descriptions components that are more similar and hence more likely to correspond to each other, based only on their syntactic structure. Experiments on real-world datasets prove the effectiveness of the proposal, and the efficiency of the corresponding implementation in the above tasks. Show more

Keywords: First-Order Logic, Logic Programming, Similarity/Distance Measures

DOI: 10.3233/FI-2009-0004

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 43-66, 2009

Authors: Giesen, Joachim | Schuberth, Eva | Stojaković, Miloš

Article Type: Research Article

Abstract: We show that any comparison based, randomized algorithm to approximate any given ranking of n items within expected Spearman's footrule distance n^{2} /ν(n) needs at least n (min{log ν(n), log n} − 6) comparisons in the worst case. This bound is tight up to a constant factor since there exists a deterministic algorithm that shows that 6n log (n) comparisons are always sufficient.

Keywords: algorithms, sorting, ranking, Spearman's footrule metric, Kendall's tau metric

DOI: 10.3233/FI-2009-0005

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 67-72, 2009

Authors: Gorawski, Marcin | Dyga, Adam

Article Type: Research Article

Abstract: This paper describes the idea of a multi-dimensional bucket index designed for efficient indexing of telemetric readings. This data structure answers spatio-temporal range queries concerning utility usage within user selected region and time. In addition, it has a capability to adjust to incoming data and therefore is suitable to process data of highly dynamic nature. The paper also presents a stochastic prediction method to estimate utility usage in the near future.

Keywords: indexing of telemetric readings, bucket index, utility usage prediction, exponential smoothing, spatial data warehouse

DOI: 10.3233/FI-2009-0006

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 73-86, 2009

Authors: Halaš, Radomír

Article Type: Research Article

Abstract: In the paper we resolve an open problem posed by D.Ciucci in [1] on the independence of axioms for SBL⌝-algebras. The main aim is to present its solution which is, in contrast to the one presented in [4], simple, transparent and easily verifiable.

Keywords: Basic logic, residuated lattice, t-norm, axiomsystem, BL-algebra, SBL-algebra, SBL⌝-algebra

DOI: 10.3233/FI-2009-0007

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 87-92, 2009

Authors: Han, Yo-Sub | Salomaa, Kai | Wood, Derick

Article Type: Research Article

Abstract: We investigate the nondeterministic state complexity of basic operations for prefix-free regular languages. The nondeterministic state complexity of an operation is the number of states that are necessary and sufficient in the worst-case for a minimal nondeterministic finite-state automaton that accepts the language obtained from the operation. We establish the precise state complexity of catenation, union, intersection, Kleene star, reversal and complementation for prefix-free regular languages.

Keywords: prefix-freeness, regular languages, nondeterministic state complexity, descriptional complexity

DOI: 10.3233/FI-2009-0008

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 93-106, 2009

Authors: Saha, Sriparna | Bandyopadhyay, Sanghamitra

Article Type: Research Article

Abstract: In this paper, a novel point symmetry based pattern classifier (PSC) is proposed. A recently developed point symmetry based distance is utilized to determine the amount of point symmetry of a particular test pattern with respect to a class prototype. Kd-tree based nearest neighbor search is used for reducing the complexity of point symmetry distance computation. The proposed point symmetry based classifier is well-suited for classifying data sets having point symmetric classes, irrespective of any convexity, …overlap or size. In order to classify data sets having line symmetry property, a line symmetry based classifier (LSC) along the lines of PSC is thereafter proposed in this paper. To measure the total amount of line symmetry of a particular point in a class, a new definition of line symmetry based distance is also provided. Proposed LSC preserves the advantages of PSC. The performance of PSC and LSC are demonstrated in classifying fourteen artificial and real-life data sets of varying complexities. For the purpose of comparison, k-NN classifier and the well-known support vector machine (SVM) based classifiers are executed on the data sets used here for the experiments. Statistical analysis, ANOVA, is also performed to compare the performance of these classification techniques. Show more

Keywords: Pattern Classification, Point Symmetry, Kd-tree, Symmetry based distance, Nearest Neighbor Rule, Line Symmetry

DOI: 10.3233/FI-2009-0009

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 107-123, 2009

Authors: Wang, Chung-Chuan | Chang, Chin-Chen | Jan, Jinn-Ke

Article Type: Research Article

Abstract: In this paper, watermarking authentication schemes for binary images are investigated. Dual-Pair Blocks (DPBs), 2 × 2 blocks with two black and two white pixels, are employed as the basic units of information embedding. With 6 distinctive patterns obtained by pixel patterns, a DPB can be represented by a senary value as the embedding information. Variable length coding is adopted to enhance the information embedding capacity of the DPB. The secret key of the watermarking is …a pseudo random function with a seed value, which selects DPBs for information embedding. Based on the aforementioned framework, two novel watermarking schemes are presented. The first one, named dual-pair block authentication (DPBA), is an irreversible one featuring high information embedding capacity, and well visual quality. The second scheme, named senary Huffman compression authentication (SHCA) scheme, supports reversible watermarking unique in the literature. Matching-pair technique is further employed both schemes to reduce the number of altered bits after watermarking for better visual quality. Experimental results show that, the DPBA scheme has the highest information embedding capacity on all comparing schemes. The average compression ratio of the reversible SHCA scheme is up to 38.96%. The average distortion rates per accessed DPB for the proposed DPBA and SHCA schemes are 0.485 and 0.46, respectively. Show more

Keywords: visual perception, watermarking authentication, DPB, DPBA, SHCA

DOI: 10.3233/FI-2009-0010

Citation: Fundamenta Informaticae, vol. 90, no. 1-2, pp. 125-155, 2009