A general theory of action languages

We present a general theory of action-based languages as a paradigm, for the description, of those computational systems which include elements of concurrency and networking, and extend this approach to describe dist.ributed systems and also t,o describe the interaction of a system, with an environment. As part of this approach we introduce the Action Language as a common model for the class of nondeterministic concurrent programming languages and define its intensional and interaction semantics in terrors of continuous transformation of environment behavior. This semantics i.s specialized for programs with stores, and extended to describe distributed computations

Electra : integrating constraints, condition-based dispatching, and features exclusion into the multiparadigm language Leda

Multiparadigm languages are languages that are designed to support more than one style of programming. Leda is a strongly-typed multiparadigm programming language that supports imperative, functional, object-oriented, and logic programming. The constraint programming paradigm is a declarative style of programming where the programmer is able to state relationships among some entities and expect the system to maintain the validity of these relationships throughout program execution. The system accomplishes this either by invoking user-defined fixes that impose rigid rules governing the evolution of the entities, or by finding suitable values to be assigned to the constrained entities without violating any active constraint. Constraints, due to their declarative semantics, are suitable for the direct mapping of the characteristics of a number of mechanisms including: consistency checks, constraint-directed search, and constraint-enforced reevaluation, among others. This makes constraint languages the most appropriate languages for the implementation of a large number of applications such as scheduling, planning, resource allocation, simulation, and graphical user interfaces. The semantics of constraints cannot be easily emulated by other constructs in the paradigms that are offered by the language Leda. However, the constraint paradigm does not provide any general control constructs. The lack of general control constructs impedes this paradigm's ability to naturally express a large number of problems. This dissertation presents the language Electra, which integrates the constraint paradigm into the language Leda by creating a unified construct that provides the ability to express the conventional semantics of constraints with some extensions. Due to the flexibility of this construct, the programmer is given the choice of either stating how a constraint is to be satisfied or delegating that task to the constraint-satisfier. The concept of providing the programmer with the ability to express system-maintained relations, which is the basic characteristic of constraints, provided a motivation for enhancing other paradigms with similar abilities. The functional paradigm is extended by adding to it the mechanism of condition-based dispatching which is similar to argument pattern-matching. The object-oriented paradigm is extended by allowing feature exclusion which is a form of inheritance exception. This dissertation claims that the integration provided by the language Electra will enable Leda programmers to reap the benefits of the paradigm of constraints while overcoming its limitations

Over-Constrained Systems in CLP and CSP

This thesis is concerned with constraint-based logical and computational frameworks for resolving and relaxing over-constrained systems. The context is provided by two such frameworks, Hierarchical Constraint Logic Programming (HCLP) and Partial Constraint Satisfaction Problem techniques (PCSP), both of which have been extensively discussed in the literature. Our work is driven by the reasons why over-constrained systems arise, the characteristics of the ‘ideal’ paradigm for resolving them, and the issue of compositionality which is very important in general if we wish to examine large systems by examining and then combining smaller parts. We abstract away from programming language issues in order to focus on constraint solving. The main original work of this thesis is divided into three parts. Firstly we present a complete method for transforming between the HCLP and PCSP representations of a problem, thus showing that theoretically they have equivalent expressive power. Secondly, having discussed compositionality in general, we present a two-stage variant of HCLP; the first stage is compositional but calculates a superset of the solutions we expect from HCLP. The second stage removes precisely those solutions which are not acceptable to HCLP, but at the cost of re-introducing HCLP’s non-compositional behaviour. We also discuss the compositional aspects of PCSP. The third part of this thesis presents Gocs, our system which allows the use of both the HCLP and PCSP approaches to problem relaxation and ordering. The Gocs integrated framework has HCLP and PCSP as special cases and also subsumes all of their separate advantages, when considering the characteristics of the ideal system for relaxing and resolving over-constrained problems. We present examples throughout the thesis, some of which are comparative and so may be used to substantiate our claims. Finally, we present conclusions and discuss further work

Feasible Form Parameter Design of Complex Ship Hull Form Geometry

This thesis introduces a new methodology for robust form parameter design of complex hull form geometry via constraint programming, automatic differentiation, interval arithmetic, and truncated hierarchical B- splines. To date, there has been no clearly stated methodology for assuring consistency of general (equality and inequality) constraints across an entire geometric form parameter ship hull design space. In contrast, the method to be given here can be used to produce guaranteed narrowing of the design space, such that infeasible portions are eliminated. Furthermore, we can guarantee that any set of form parameters generated by our method will be self consistent. It is for this reason that we use the title feasible form parameter design. In form parameter design, a design space is represented by a tuple of design parameters which are extended in each design space dimension. In this representation, a single feasible design is a consistent set of real valued parameters, one for every component of the design space tuple. Using the methodology to be given here, we pick out designs which consist of consistent parameters, narrowed to any desired precision up to that of the machine, even for equality constraints. Furthermore, the method is developed to enable the generation of complex hull forms using an extension of the basic rules idea to allow for automated generation of rules networks, plus the use of the truncated hierarchical B-splines, a wavelet-adaptive extension of standard B-splines and hierarchical B-splines. The adaptive resolution methods are employed in order to allow an automated program the freedom to generate complex B-spline representations of the geometry in a robust manner across multiple levels of detail. Thus two complementary objectives are pursued: ensuring feasible starting sets of form parameters, and enabling the generation of complex hull form geometry

Declarative theorem proving for operational semantics

iAbstract The aim of this Masters Thesis is to propose to SYSteam Nät AB, a local Internet Service Provider (ISP) in Uppsala, Sweden, how to implement IP telephony in their existing IT-infrastructure as a service to their customers. Thus the perspective of the thesis will be that of a local Internet Service Provider. Three general areas are covered in the thesis: Market and Business Model, Technology, and Economics. Important issues for SYSteam Nät AB as an established local broadband Internet Service Provider are to both retain present customers and to attract new customers. Some believe that offering value added services such as IP telephony could do this. Implementation of IP telephony can be done in different ways to fulfil SYSteam Nät’s requirements. The analysis leads to a proposal of how SYSteam Nät could implement IP telephony. This involves many multi-faceted business, technical, and financial issues; each aspect is examined in this thesis. ii Sammanfattnin

Three social science disciplines in Central and Eastern Europe: handbook on economics, political science and sociology (1989-2001)

Content: Ulrike Becker, Max Kaase, Gabor Klaniczay, and Vera Sparschuh: Social Sciences in Central and Eastern Europe on the Verge of EU Enlargement (7-10); Andrei Plesu: Financing Difference. Fostering the Social Sciences in the Field of Tension Between Homogenization and Differentiation (12-16); Elemer Henkiss: Brilliant Ideas or Brilliant Errors? (17-24); Janos Matyas Kovacs: Business as (Un)usual (26-33); Mitko Dimitrov: Bulgaria (34-49); Frantisek Turnovec: Czech Republic (50-64); Tiia Püss: Estonia (65-82); Laszlo Csaba: Hungary (83-101); Raita Karnite: Latvia (102-120); Linas Cekanavicius: Lithuania (121-134); Tadeusz Kowalik: Poland (135-151); Paul Dragos Aligica: Romania (152-167); Julius Horvath: Slovakia (168-186); Joze Mencinger: Slovenia (187-194); Hans-Jürgen Wagener: Demand and Supply of Economic Knowledge in Transition Countries (195-203); Hans-Dieter Klingemann: Political Science in Central and Eastern Europe: National Development and International Integration (206-212); Georgi Karasimeonov: Bulgaria (213-225); Jan Holzer and Pavel Pseja: Czech Republic (226-245); Raivo Vetik: Estonia (246-257); Mate Szabo: Hungary (258-274); Andris Runcis: Latvia (275-285); Algis Krupavicius: Lithuania (286-305); Stanislaw Gebethner and Radoslaw Markowski: Poland (306-321); Daniel Barbu: Romania (322-342); Darina Malova and Silvia Mihalikova: Slovakia (343-357); Danica Fink-Hafner: Slovenia (358-374); Pal Tamas: Followers or Activists? Social Scientists in the Reality Shows of Transformation (376-385); Nikolai Genov: Bulgaria (386-404); Michal Illner: Czech Republic (405-424); Mikk Titma: Estonia (425-436); Denes Nemedi and Peter Robert: Hungary (437-451); Aivars Tabuns: Latvia (452-466); Anele Vosyliute: Lithuania (467-483); Janusz Mucha and Pawel Zalecki: Poland (484-501); Maria Larionescu: Romania (502-517); Zuzana Kusa, Bohumil Buzik, Ludovit Turcan and Robert Klobucky: Slovakia (518-535); Frane Adam and Matej Makarovic: Slovenia (536-547); Piotr Sztompka: The Condition of Sociology in East-Central Europe (548-556); Mihaly Sarkany: Cultural and Social Anthropology in Central and Eastern Europe (558-566); Thomas Kucera and Olga Kucerova: Population science in Central and Eastern Europe: Implications for Research and Practice (567-577); Marie-Claude Maurel: Central European Geography and the Post-Socialist Transformation. A Western Point of View (578-587); Grazyna Skapska: Law and Society in a Natural Laboratory: the Case of Poland in the Broader Context of East-Central Europe (588-603)