Turku Centre's research while affiliated with University of Turku and other places
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Publications (166)
The latest improvements in the technology of digital devices allow designers to build whole systems on a single silicon chip. New problems arise in this context, one of them being the complexity of interconnections. Optimizing interfaces has become a tedious design step. Another issue is the power consumption, for which globally asynchronous locall...
The problem of finding 2^n when n is given is mathematically trivial, but computationally intractable. We show how to compute the most significant digit of the ternary representation of 2^n in polynomial time.
Differential equations are used in control theory to describe a system and its behaviour. They define explicitly the relationships between continuous variables during the evolution of the system. In this paper, we introduce the use of differential equations as primitive actions. The semantics is given with the weakest liberal precondition predicate...
There is a lack of a representative set of test problems for comparing global optimization methods. To remedy this a classification of essentially unconstrained global optimization problems into unimodal, easy, moderately difficult, and difficult problems is proposed. The problem features giving this classification are the chance to miss the basin...
All work needs to be articulated in terms of "Who should do what, how, when and where", and this becomes more complicated as more actors are involved. The use of computers in cooperative work implies new needs for articulations due to the individual's dynamic and changing situation in respect to collective and individual aspects. The computers shou...
Watson-Crick complementarity is one of the central components of DNA computing, the other central component being the massive
parallelism of DNA strands. While the parallelism drastically reduces (provided the laboratory techniques will become adequate)
the computational complexity, the complementarity is the actual computational tool “freely” avai...
KAT (Kleene Algebra with Tests) have proved to be useful for reasoning about programs in a partial correctness framework. We describe DRA (demonic Refinement Algebra), a variation of KAT for total correctness and illustrate its modeling and reasoning power with a number of applications and examples. TUCS Laboratory TUCS Learning and Reasoning Labor...
In chapter 1 we suggested that a program be structured as a set of objects. Each object consists of actions and/or methods, where the actions are executed autonomously (following a specific execution rule) and the methods are executed when they are called. In this chapter, we consider a simpler version of this model; we eliminate the methods altoge...
Under the assumption that a quantum computer can exactly copy quantum superpositions, we show that NP-complete problems can be solved probabilistically in polynomial time. We also propose two methods that could potentially allow to avoid the use of a quantum copymachine.
The D0L and DT0L power series are generalizations of D0L and DT0L languages. We continue the study of these series by investigating various decidability questions concerning the images of D0L and DT0L power series.
Very little is known about the algorithmic complexity of the HDT0L sequence equivalence problem. We determine this complexity for uniform HDT0L systems by giving the exact bound indicating how many initial terms have to be compared to guarantee the sequence equivalence.
We prove that for each positive integer n; the nite commutative language E n = c(a 1 a 2 a n ) possesses a test set of size at most 5n: Moreover, it is shown that each test set for E n has at least n 1 elements. The result is then generalized to commutative languages L containing a word w such that (i) alph(w) = alph(L); and (ii) each symbol a 2 al...
We describe a GA-based concept learning/theory revision system DOGMA and discuss how it can be applied to relational learning. The search for better theories in DOGMA is guided by a novel fitness function that combines the minimal description length and information gain measures. To show the efficacy of the system we compare it to other learners in...
We give a bound for the sequence equivalence problem of polynomially bounded D0L systems which depends only on the size of the alphabet.
We make a brief survey of some of the most important recent results in the area of contextual languages. We are mostly concerned with new classes of contextual languages more appropriate from natural languages point of view, the concept of mildly context-sensitivity playing a central role here, and also with some other topics, such as computational...
In this paper we present an approach for modelling procedures (as they occur in imperative programs) in a weakest precondition semantics. We show how this approach can be implemented in the mechanisation of the refinement calculus theory in the HOL system. That makes it possible to derive a number of correctness and refinement properties of procedu...
We investigate the computational complexity of the basic type of contextual languages, that is, the ones introduced by Marcus in [M2] and called subsequently external contextual languages. Our main result states that the most important family of external contextual languages, namely that of languages generated by grammars with context-free choice,...
In this paper we first bridge some problems of formal language theory to those of cryptography. In doing so, new problems in both fields are proposed. Motivated by the CD grammar systems [1], we then describe a general cooperatively distributed ciphering system and hashing system. These CD ciphering and hashing systems could be much more powerful t...
Introduction The basic object of this chapter is a word, that is a sequence -- finite or infinite -- of elements from a finite set. The very definition of a word immediately imposes two characteristic features on mathematical research of words, namely the discreteness and the noncommutativity. Therefore the combinatorial theory of words is a part o...
We give a survey of simple undecidability results and open problems concerning matrices of low order with integer entries. Connections to the theory of finite automata (with multiplicities) are also provided.
We investigate the exact status and role of specication variables (auxiliaries) in Hoare triples, showing that their interpretation is not as straightforward as one might intuitively think. In particular, we uncover the connection between specication variables and both angelic and demonic nondeterminism contained in a specication. As a result, we s...
In this document we introduce a software package BinClass for the classification of binary vectors and analysis of the classification results. First we will give brief introduction to the mathematical foundations and theory of clustering, cumulative classification and mixture classification. We also introduce methods for analysis of the classificat...
As is well known, two words commute if and only if they are powers of a same word; two formal power series with coecients in a eld commute if and only if they are combinations of a third series. On the other hand, almost nothing is known about the commutation of sets of words. We give in this paper a similar characterization for the commutation wit...
Watson-Crick complementarity can be viewed as a language-theoretic operation: "bad" words obtained through a generative process are replaced by their complementary ones. This idea seems particularly suitable for Lindenmayer systems. D0L systems augmented with a specific complementarity transition, Watson-Crick D0L systems, have turned out to be a m...
The phenomenon known as Watson-Crick complementarity is basic both in the experiments and theory of DNA computing. While the massive parallelism of DNA strands makes exhaustive searches possible, complementarity constitutes a powerful computational tool. It is also very fruitful to view complementarity as a language-theoretic operation: "bad" words...
Component-based software engineering means constructing new systems from already existing, service-providing components. Object-based software engineering means constructing a new system in terms of interacting, distinct units of information and services called objects. Both components and objects have encapsulation properties and are accessed via...
We discuss several open problems in combinatorics of words and related areas. The problems fall into six different problem areas.
The problem of mining association rules for fuzzy quantitative items was introduced and an algorithm proposed in [7]. However, the algorithm assumes that fuzzy sets are given. In this paper we propose a method to find the fuzzy sets for each quantitative attribute in a database by using clustering techniques. We present a scheme for finding the opt...
In spite of its simple formulation, the problem about the synchronization of a finite deterministic automaton is not yet properly understood. The present paper investigates this and related problems within the general framework of a composition theory for functions over a finite domain N with n elements. The notion of depth introduced in this conne...
Watson-Crick complementarity has been used as a basis for massive parallelism in DNA computing. Also its use in an operational sense has turned out to be very promising in the study of Watson-Crick D0L systems. The latter generalize D0L systems in a way not investigated so far in the theory of Lindenmayer systems. The complexity of the "trigger" is...
We study safe language mechanisms for modularization and concurrency. Our contributions are a case study and several new language mechanisms with associated theories. Our motivation is twofold. First, the construction of software used in safety-critical systems requires expressive specification and programming languages that are themselves safe. Se...
We prove two results on commutation of languages. First, we show that the maximal language commuting with a three element language, i.e. its centralizer, is rational, thus giving an affirmative answer to a special case of a problem proposed by Conway in 1971. Second, we characterize all languages commuting with a three element code. The characteriz...
In flexible manufacturing systems (FMS) the interaction between the production planner and the scheduling system is essential. This is a typical situation in printed circuit board (PCB) assembly. We discuss the structure and operation of an interactive scheduling system for surface mount component printing involving multiple criteria. The user can...
In present paper we study the use of the expectation maximization (EM) algorithm in classification. The EM-algorithm is used to calculate the probability of each vector belonging to each class. If we assign each vector to the class of maximal probability we get a classification minimizing a certain log-likelihood function. By analyzing these probab...
In this paper we study the problem of semantic substitutability of objects. First we give semantics of classes, objects and inheritance in the presence of dynamic binding. For this purpose we extend Cook and Palsberg's denotational semantics of stateless classes and inheritance by adding state. We build our theory on the basis of the refinement cal...
During the last ten years, data mining, also known as knowledge discovery in databases, has established its position as a prominent and important research area. Mining association rules is one of the important research problems in data mining. Many algorithms have been proposed to find association rules in databases with binary attributes. In this...
We consider so-called Fatou-type properties of rational languages and relations. For example, if the rational expression E(X 1 ; : : : ; X n ) over arbitrary languages X 1 ; : : : ; X n represents a rational language, then each language X i can be replaced by a rational language Y i such that E(X 1 ; : : : ; X n ) = E(Y 1 ; : : : ; Y n ) holds and...
In this paper we present an approach for modelling functional procedures (as they occur in imperative programming languages) in a weakest precondition framework. Functional procedures are modelled in their full generality; thus the body of a functional procedure can be built using standard specification syntax, including nondeterminism, sequential...
We describe how an existing tool is extended to allow exploratory reasoning in program algebras with theorem proving support. The existing tool (TkWinHOL and the Refinement Calculator) provides a graphical user interface to the window inference reasoning system for the HOL theorem prover. We show how a user with a small amount of work can build an...
Electronics industry is a major part of modern manufacturing, and electronic systems play an increasingly important role in a majority of today’s products. Electronic systems are usually implemented with printed circuit boards (PCBs), and, consequently, PCB assembly has become an important sector of the electronics manufacturing industry overall. H...
In a high-mix low-volume production environment of printed circuit board assembly, the production eciency depends strongly on the organization of the printing jobs. The present study discusses the problem of arranging the jobs of one machine into groups in such a way that the job change costs will be minimized when the costs depend on the number of...
We study Fatou properties of D0L power series and related decision problems.
Straightforward implementation of the exact pairwise nearest neighbor (PNN) takes O(N 3 ) time, where N is the number of training vectors. This is rather slow in practical situations. Fortunately much faster implementation can be obtained with rather simple modifications to the basic algorithm. In the present paper we propose a fast O(tN 2 ) time i...
We study the notion of class refinement in a concurrent object-oriented setting. Classes, defining attributes and methods, serve as templates for creating objects. For expressing concurrency, actions are added to classes and methods with guards are considered. A class can be defined by inheriting from a given class. Class refinement is defined to s...
Action Systems is a predicate transformer based formalism for the development of reactive and distributed systems by refinement. Lately, Action Systems was extended with a differential action that models continuous behaviour. Such action systems capture hybrid systems, where a discrete controller interacts with some continuously evolving environmen...
The ambient calculus and the P-systems are models developed in di erent areas of computer science. Still, they are based on similar concepts and structures and are inspired from the same natural model of computation [BeBo92]. On this basis, we point out how to transfer ideas and results from one framework to the other. We prove that any P-system ca...
From the perspective of librarianship some alarming, rather global changes
A probabilistic extension of the refinement calculus has been successfully applied in the design of safety-critical systems. The approach is based on a firm mathematical foundation within which the reasoning about correctness and behavior of the system under construction is carried out. The framework allows us also to obtain a quantitative assessme...
We investigate interconnections between many-valued truth functions and functions defined by finite deterministic automata. Propositions in one of the theory have often their natural counterpart in the other theory. Such is the case with problems about completeness, as well as with
We show how safety analysis can guide the formal development of controlling
We describe two approaches for context handling in the Refinement Calculus framework. They show how information relevant for total correctness can be transported from one place of a program to another and then used for refinement of program components. Both approaches have been formalised in the HOL theorem proving system and integrated into a tool...
Under the assumption that a quantum computer can exactly copy quantum superpositions, we show that NP-complete problems can be solved probabilistically in polynomial time. We also propose two methods that could potentially allow to avoid the use of a quantum copymachine. Supported by the Academy of Finland under grant 14047. To be presented at MCU'...
We show how solutions to typical problems of High School and #rst-year University Mathematics can be written using structured derivations. Such a derivation extends the calculational proof format with subderivations that allow inferences to presented at di#erent levels of detail. They also constitute a new paradigm where the whole solution process...
We study program states that are described as tuples, i.e., product state spaces. Modeling programs as predicate transformers, we define a product operator on program statements that describes the independent execution of statements on disjoint state spaces. The algebraic properties of this product operator are studied, in particular the basic mono...
The paper presents an extension of the action system formalism to reason about probabilistic systems which can be implemented in a parallel or distributed manner. We focus on modelling safety issues for such systems. We start from a sequential description of the problem where the level of overall system safety is given. We data refine an initial sp...
Motivated by wavelength division multiplexing in all-optical networks, we consider the problem of finding an optimal (with respect to the least possible number of wavelengths) set of f + 1 internally node disjoint dipaths for every pair of distinct nodes in the binary r-dimensional hypercube, where 0 f ! r. This system of dipaths serves as a routin...
Representations of finite languages as a product (catenation) of languages are investigated, where the factor languages are "prime", that is, cannot be decomposed further in a nontrivial manner. In general, such prime decompositions are not unique - even the number of factors can vary exponentially. The paper investigates the uniqueness of prime de...
The action systems framework supporting formal circuit derivations has been successfully applied to synchronous VLSI design. The present paper presents a C++ application that translates descriptions of synchronous action systems into VHDL code, after their formal transformation from the initial high-level specifications into concrete enough format.
We consider the internal rate of return (IRR) decision rule in capital budgeting problems with fuzzy cash flows. The possibility distribution of the IRR at any
We introduce a new computability model, of a distributed parallel type, based on the notion of a membrane structure. Such a structure consists of several cell-like membranes, recurrently placed inside a unique "skin" membrane. A plane representation is a Venn diagram without intersected sets and with a unique superset. In the regions delimited by t...
We consider several open problems of Karhumaki, Mignosi, and Plandowski, cf. [KMP], concerning the expressibility of languages and relations as solutions of word equations. We show first that the (scattered) subword relation is not expressible. Then, we consider the set of k-power free finite words and solve it negativelly for all nontrivial intege...
Apart from the massive parallelism of DNA strands, the phenomenon known as Watson-Crick complementarity is basic both in the experiments and theory of DNA computing. The parallelism makes exhaustive searches possible, whereas the complementarity is a powerful computational tool. This paper investigates complementarity as a language-theoretic operat...
In this work we present a new chain of undecidability reductions, which begins from the classical halting problem of Turing machines and ends to the undecidability proof of the equivalence problem for finite substitutions on regular languages in Chapter 4. This undecidability result was originally proved by L. Lisovik in 1997. We present a new proo...
We define a new type of tree automaton with output as a generalization of Moore automata. The new structure allows us to study how Moore's gedanken-experiments, where the experimenter knows only the inputs and outputs of the automaton, are applicable to trees. In particular, we study simulation, minimality and universality of such automata. TUCS Re...
Using well-known results, we show that one can effectively construct algorithms related to the lexicographical order with surprisingly low time complexity. In particular, we consider algorithms for finding minimal words of given length in regular and context-free languages running in O(c) time when
We consider the question of whether the famous Parikh's theorem holds with multiplicities i.e., for formal power series instead of languages. We introduce two families of semilinear formal power series over a commutative product monoid. The strict hierarchy of algebraic, rational, recognizable and semilinear formal power series is proved and in thi...
A method for translating various existing universal devices to extended H systems is discussed. Dual contexts are introduced as a useful tool in the analysis of universal H systems. Some practical biological considerations are also considered.
We describe a GA-based concept learning/theory revision system DOGMA and discuss how it can be applied to relational learning. The search for better theories in DOGMA is guided by a novel fitness function that combines the minimal description length and information gain measures. To show the efficacy of the system we compare it to other learners in...
We investigate the relationship between specifications by means of Hoare triples and specification statements in the Refinement Calculus style, focusing on the issue of sharpness. In particular, we examine the exact status and role of specification variables, showing that their interpretation is not as straightforward as one might intuitively think...
We introduce and study relations on words which generalize the factor relation, being restrictions of the subword relation. We give an equivalent condition for the finite basis property for these relations which generalizes the well-known theorem of Higman. Some language-theoretic gaps for infinite antichains are also presented. 1
We prove in HOL that three proof systems for classical first-order predicate logic, the Hilbertian axiomatization, the system of natural deduction, and a variant of sequent calculus, are isomorphic. The isomorphism is in the sense that provability of a conclusion from hypotheses in one of these proof systems is equivalent to provability of this con...
We study the basic properties of Galois rings and character sums over them. Galois rings are presented as Witt vector rings. With Galois rings we construct efficient binary non-linear codes, such as Kerdock code and Delsarte-Goethals codes, as images of linear codes over alphabet Z 4 . We present also sequence families that are at the moment best k...
We investigate the problem of finding monoids that recognize languages of the form L 1 T L 2 , where T is an arbitrary set of trajectories. Thereby, we describe two such methods: one based on the so called trajectories monoids and the other based on monoids of matrices. Many well-known operations such as catenation, bi-catenation, shuffle, literal...
This paper reports on the results of a study examining factors having an
It is shown that the universe problem L(A
Hybrid action systems extend a conventional action system with a guarded differential equation --- a differential action --- that defines evolution of continuous variables while the guard remains true. The new action is given a weakest liberal precondition semantics, which is illustrated by examples from a train model. The example motivates a discu...
We study program states that are described as tuples, i.e., product state spaces. We show how to add program variables and assignment notation to simply typed lambda calculus in order to describe functions, relations and predicate transformers on such spaces in a concise way. We define an operator on program statements that describes the independen...
Linear predictive analysis is a standard technique in modern digital speech processing. This makes it an interesting implementation area for asynchronous design. We present an asynchronous speed-independent circuit implementation of a linear predictive analysis system. The implementation is built around a program ROM into which the algorithm is enc...
We give characterizations of recursively enumerable languages starting from copy languages, that is languages of the form fxx j x 2 Lg, where L is a regular language and x is the barred version of x. One characterization uses an intersection of morphic images of two copy languages, the other one uses a quotient of morphic images of two copy languag...
We give a complete proof of Theorem 3.1 in [2]. A pathological exception of Theorem 4.3 in [2] is exhibited and a condition to remove it is mentioned. TUCS Research Group
With the emergence of the Object Management Group's CORBA (Common Object Request Broker Architecture) and comparable platforms heterogeneous and distributed computing is facilitated. Providing location-, language-, and platform-transparency, CORBA promotes the independent development of software components and standardizes the interaction between c...
We describe an application of DOGMA, a GA-based theory revision system, to MDL-based rule enhancement in supervised concept learning. The system takes as input classification data and a rule-based classification theory, produced by some rule-based learner, and builds a second, hopefully more accurate, model of the data. Unlike most theory revision...
Templates are a powerful feature of C++. In this article a template library for a special class of sparse vectors is outlined. For these vectors, the sparseness structure of the vectors can be arbitrary but must be known at compile time. In this case it suffices to store only the nonzero elements of the vectors, no indexing information about the sp...
The arrangement of operations in a production line for mounting the surface components on a printed circuit board is discussed. The production environment has a wide range of different products, which causes frequent set-up operations. The overall productivity of the line depends heavily on how the printing operations are organized. Set-ups cause d...
This report discusses how to refine reactive systems using the HOL theorem prover. We show how Action Systems -- the formal framework supported -- can be formalised in HOL. We describe a simple refinement example. We also discuss how the work presented here can be used in connection with the Refinement Calculator, a tool supporting program refineme...
In this paper IS requirement analysis is discussed from the
A language \(L \subseteq \sum {^* }\)is confluent with respect to a given quasi order ≤ on σ* if, for any x,y ε L, there is z ε L such that x ≤ z and y ≤ z. L is confluent with respect to ≤ in generalized sense if it is a finite union of languages confluent with respect to ≤. We investigate in this paper the decidability of the generalized confluen...
We address the question 'how to measure goodness of time-processor optimal PRAM simulations'. Instead of measuring only the asymptotic complexity of simulation time, we attempt to take into account all aspects of simulations exactly. We present a goodness function framework and propose a generic function for measuring the goodness. Keywords: Time-p...
We study the use of genetic algorithms in rule-based concept learning. The developed system, JGA, is capable of learning disjunctive concepts in First Order Logic. We take a two-leveled approach that combines features from both the Michigan and Pittsburgh approaches. We compare the system in several propositional domains with three well-known conce...
Sharing is a popular method for introducing divergency in genetic algorithms for multimodal function optimization. In this paper we define three sharing methods and investigate their applicability for concept learning of disjunctive rules from preclassified examples. The sharing methods are incorporated in JGA, a genetic algorithm based concept lea...
A word is called primitive if it cannot be expressed as the power of another word. Morphisms preserving primitive words are investigated. Similarly to the word case, each square-free morphism is a primitive morphism but the converse does not hold. A precise characterization of primitive morphisms is provided in terms of pure codes. An easily testab...
We extend the Action-Oberon language for executing action systems with typebound actions. Type-bound actions combine the concepts of type-bound procedures (methods) and actions, bringing object orientation to action systems. Typebound actions are created at runtime along with the objects of their bound types. They permit the encapsulation of data a...
The action systems formalism has been successfully used as a formal framework for reasoning about concurrent behaviour. Circuits, both synchronous and asynchronous, exhibit concurrent behaviour. In this paper, we combine the design of asynchronous circuits with action systems. We show how (quasi) delay-insensitive circuits can be modelled as action...
We describe global optimization problems from three different fields representing many body potentials in physical chemistry, optimal control of a chemical reactor, and fitting a statistical model to empirical data. Historical backgrounds for each of the problems as well as the practical significance of the first two are given. The problems are sol...
The so-called replication operation is studied in the case when several insertion contexts consisting of letters are used, as well as in the case when this operation is applied to several strings. Some striking differences, depending on the technical details of the setup, are observed in the generative power of this operation.
The security of information is becoming increasingly discussed. In this paper I will show why the subject is of importance and what economic losses inadequate ISEC can bring an organisation.
It is well known that equality sets between two morphisms possess a remarkable generative capacity: an arbitrary recursively enumerable set is obtained from an equality set by certain simple operations. Interconnections between simplicity of computations and structural primitivity of words in equality sets have also been observed. The paper discuss...
There is a lack of a representative set of test problems for comparing global optimization methods. To remedy this a classification of essentially unconstrained global optimization problems into unimodal, easy, moderately difficult, and difficult problems is proposed. The problem features giving this classification are the chance to miss the basin...
Calculations for scheduling projects using activity networks often rely on strong assumptions that are not always acceptable. One assumption is that the duration of each activity can always be estimated as a single non-negative value. This can sometimes be an unrealistic assumption. This is often the case in field like research and development wher...
Citations
... Da Rosal [48] argues that the reason why students find FM courses challenging lies in their mathematical background from high school. This opinion has been raised even before [8,31,48] and highlights the need for a fundamental change in high school education and more focus on discrete and applicable mathematics, instead of pedagogical issues. Gibson [25] blames neglecting case studies and illustrative examples during teaching; Robinson [47] mentions the lack of visibility of industrial use; Mandrioli [38] blames miscommunication, and fuzzy terminology, and suggests the use of "push button" and user-friendly tools; Buote [11] claims that tools could be misleading if mathematical fundamentals and concepts are not clearly understood. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/272463716155396-1441971820401_Q64/Ralph-Johan-Back.jpg)
... These methods are especially well-suited for modeling asynchronous self-timed behavior, where sequencing of events is based on handshakes between units [11]. Also the action systems formalism has recently been adapted to asynchronous circuit design [17,18,19,20]. However, the majority of modern digital hardware still uses synchronous techniques. ...
Reference: Design of Synchronous Action Systems
![[object Object]](https://i1.rgstatic.net/ii/profile.image/764701986287616-1559330569215_Q64/Juha-Plosila.jpg)
... Let us apply our refinement laws to a larger program. In the development, we will make use of the technique that propagates context information via the assertion statement [LvW97,Gro00]. Below we list several non-trivial laws for propagating context information. ...
Reference: Refining Exceptions in Four-Valued Logic
![[object Object]](https://i1.rgstatic.net/ii/profile.image/272272313286678-1441926186487_Q64/Linas-Laibinis.jpg)
... In particular, MDA-ANN combinations have resulted in consistently greater accuracy (Voges and Pope 2000; Michalewicz et al. 2005; Ko and Lin 2006). Genetic algorithms have been used for feature selection or parameter selection for an ANN (Hekanaho 1997; Brabazon and Kennan 2004), MDA (Galvao 2001), and ANN which derived if-then rules (Sikora and Shaw 1994). ...
... It also uses a network of genetic nodes, but takes a co-evolutionary approach (Anglano et al., 1998), i.e. two algorithms are used to converge to a solution. DOGMA (Hekanaho, 1996(Hekanaho, , 1998 is a system, which uses a combination of the Pittsburgh and Michigan approach on different levels of abstraction. All these systems use a simple bit string representation. ...
... The model was suggested in 1997 by Mihalache and Salomaa [5]. For motivation underlying the concept of Watson-Crick D0L systems and some recent results see [4,6,11,12,14]. ...
... A number of researchers have carried out studies on end-user support, for instance Munkvold (2003) identified end-user qualities (IT-skill, Computer self-efficacy and IT-involvement) that are important for explaining differences in usage of support (ibid). Auer (1998) studied on how to improve skills in end user computing; he concentrated on impact of Information System (IS) usage, user characteristics and organizational support on IS skills. According to Munkvold(2003) to be competitive, organizations need to optimize use of IT-resources by improving end-user quality (ibid); this can be achieved if end-users within the organizations are offered efficient and effective IT support from the IT departments. ...
... Even though contextual grammars were introduced to give an appropriate model to natural languages, the basic variants of internal contextual languages failed to contain non-context-free constructions and also they contain non-semilinear languages (Ehrenfeucht et al. 1995;Ilie 1996). Further, the membership problem for the above families of languages still remains open (Ilie 1997b) or is solvable with exponential time. Marcus et al. (1996a) considered two new classes of contextual grammars named global maximal and local maximal, respectively. ...
... [681,685] product models,[604,655,735] project evaluation,[610] project management,[973] Prolog,[251] protection relays,[641,646] protein folding,[118, 119,880] de novo,[995] hydration,[236] lattice model,[743,125,16, 160,236] proteins bibliography,[825] fingerprints,[1008] ligands,[529] structure comparison,[701,734] structure comparisons,[468] structure prediction,[931] puzzle,[855] QAP,[37] QSAR,[569] quantum computation theory,[628] quantum computer copying,[664,677] error correction,[680] quasi-,[415] tutorial,[480] quantum computing,[256,338,371] Schrödinger's equation,[189] super conducting,[348] Berry phase,[212] bibliography,[826] Boolean functions,[302] Bose-Einstein condensate,[225] bulk spin,[178] decoherence,[229] electrons on helium,[177] Fourier transform,[525] implementation,[315] ion trap,[21] Josephson junction,[205,215,216,218,219,231] leakage,[222] molecular magnets,[174] NMR,[175,212,224] open problems,[250] optical lattice,[226] physical realization,[211] quasi-,[368] review,[174,175,176,177,178,183,185,189,190,197,198,199,205,209,210,211,212,215,216,217,218,219,220,222,224,225,226,227,229,231,233,234] solid state,[954] superconducting,[192] theory,[141] trapped ion,[199,234] tutorial,[306] quantum cryptography review,[223] quantum memory,[281] quantum teleportation,[181] qubits photon,[190] radar imaging,[875] radio coverage,[660] radioactive decay,[865] radiotherapy beam optimization,[947] random number generators,[123] rapid prototyping,[597,652,653] reasoning proofs,[996] regression,[589] fuzzy,[416] iPLS,[25] nonlinear,[423] ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/272797289152517-1442051350174_Q64/Mika-Hirvensalo.jpg)
... This article documents the formalisation of computationally important algebraic concepts and structures within a larger project of making variants of Kleene algebras and relation algebras available in the Isabelle proof assistant. It presents variants of test semirings [17] in Isabelle together with their expansions to Kleene algebras and demonic refinement algebras with tests [15,22,23]. The latter two algebras have been applied in the verification and correctness of sequential programs; the first one in partial correctness, the second one in a total correctness setting. ...
