Logical Foundations of Object-Oriented and Frame-Based Languages

We propose a novel logic, called Frame Logic (abbr., F-logic), that accounts in a clean, declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the object-oriented paradigm as classical predicate calculus stands to relational programming. The syntax of F-logic is higher-order, which, among other things, allows the user to explore data and schema using the same declarative language. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof procedure. This paper also discusses various aspects of programming in declarative object-oriented languages based on F-logic

Making object-oriented databases more knowledgeable (From ADAM to ABEL)

Tesis leida en la Universidad de Aberdeen. 178 p.The salient points of this thesis are as follows: • Object-Oriented Databases can help in solving the impedance mismatch problem by introducing methods. However, methods have sometimes been overused in the sense th at the code encapsulated refers not only to how the operation is implemented but also to other kinds of knowledge that are implicit in the code. The disadvantages of this approach for modelling integrity constraints, user-defined relationships and active behaviour are pointed out. • The ADAM Object-Oriented Database has been extended to allow the designer to specify integrity constraints declaratively. A constraint equation approach is implemented th at supports the inheritance of constraints. • A need for semantic-rich user-defined relationships has been identified. In this thesis, relationships are represented as objects. An approach to enhance the semantics of relationships in both its structural and behavioural aspects is presented. The most novel idea of the approach presented is the support of the inferred properties and the operational semantics of relationships. • Active Databases have recently become an im portant area of research. This thesis shows how to extend an Object-Oriented Database with active capabilities. The principal contribution lies in representing as ‘first-class’ objects not only the active rules but also the rule manager itself. Hence, besides handling active rules as any other object in the system, future requirements can be supported just by specialising the current rule manager. • Active rules have been proposed for several purposes. Several examples, are given of the direct use of rules. However, higher level tools can be provided of which rule

Concepts and their Use for Modelling Objects and References in Programming Languages

In the paper a new programming construct, called concept, is introduced. Concept is pair of two classes: a reference class and an object class. Instances of the reference classes are passed-by-value and are intended to represent objects. Instances of the object class are passed-by-reference. An approach to programming where concepts are used instead of classes is called concept-oriented programming (CoP). In CoP objects are represented and accessed indirectly by means of references. The structure of concepts describes a hierarchical space with a virtual address system. The paper describes this new approach to programming including such mechanisms as reference resolution, complex references, method interception, dual methods, life-cycle management inheritance and polymorphism.Comment: 43 pages. Related papers: http://conceptoriented.com

Analyzing UVM reuse

Abstract. This thesis investigates Universal Verification Methodology’s (UVM) reuse possibilities. Initally, the object-oriented features of the UVM’s programming language SystemVerilog (SV), are introduced. Those features are one enabling factor in UVM reuse. The work also provides a brief overview to the development history of UVM and presents its properties. The structure of a conventional UVM testbench is also demonstrated. Finally, the features that make the UVM testbench more reusable are briefly introduced. In the practical part of the study, a UVM testbench is made for Nordic Semiconductor’s Introproject. The testbench was created with extensive comments so that beginners would get the most out of it. The methods that make the testbench reusable are also applied to the testbench. At the end of the practical part, the reuse possibilities of the testbench were tested by changing the Design Under Test (DUT). Modifications were made to the testbench in order to match the new features of the DUT.UVM uudelleenkäytön analysointi. Tiivistelmä. Tämä diplomityö tutkii Universaalin varmennusmenetelmän (UVM) uudelleenkäyttömahdollisuuksia. Aluksi UVM:n ohjelmointikielen, SystemVerilogin olio-ohjelmointipohjaisia ominaisuuksia käydään läpi. Nämä ominaisuudet ovat yksi mahdollistava tekijä UVM uudelleenkäytössä. Työssä tehdään lisäksi lyhyt katsaus UVM:n kehityshistoriaan ja esitellään myös sen ominaisuudet sekä tavanomaisen UVM-testipenkin rakenne. Lopuksi esitellään lyhyesti ominaisuuksia, jolla saa tehtyä UVM testipenkistä paremmin uudelleenkäytettävän. Työn käytännön osuudessa tehdään UVM-testipenkki Nordic Semiconductorin Introprojektiin. Testipenkki tehtiin laajasti kommentoimalla, jotta aloitteleva testipenkin tekijä saa siitä mahdollisimman paljon irti. Testipenkin tekemisessä käytettiin myös menetelmiä, joita esiteltiin aiemmassa teoriakappaleessa. Käytännön osuuden lopuksi testattiin testipenkin uudelleenkäyttöä muuttamalla testissä olevaa komponenttia. Testipenkkiin tehtiin muutokset, jolla se saatiin taas vastaamaan komponentin tarpeita

A policy based role object model

Enterprise roles dejine the duties and responsibilities of the individuals which are assigned to them This paper introduces a framework for the management of large distributed systems which makes use of the concepts developed in role theory. Our concept of a role groups the specifications of management policies which define the rights and duties corresponding to that role. Individuals m y then be assigned to or withdrawn from a role, to enable rapid and flexible organisational change, without altering the Specification of the policies. We extend this role concept to include relationships as means of specifying required interactions, duties and rights between related roles. Organisations may contain large numbers of similar roles with multiple relationships between them, so there is a need for reuse of specifications. Role and relationship classes permit multiple instantiation and inheritance is used for incremental extension of the organisational structure with minimal specification effort. We also briefly examine consistency and auditing issues related to this role framework. 1

Policy based roles for distributed systems security

Distributed systems are increasingly being used in commercial environments necessitating the development of trustworthy and reliable security mechanisms. There is often no clear informal or formal specification of enterprise authorisation policies and no tools to translate policy specifications to access control implementation mechanisms such as capabilities or Access Control Lists. It is thus difficult to analyse the policy to detect conflicts or flaws and it is difficult to verify that the implementation corresponds to the policy specification. We present in this paper a framework for the specification of management policies. We are concerned with two types of policies: obligations which specify what activities a manager or agent must or must not perform on a set of target objects and authorisations which specify what activities a subject (manager or agent) can or can not perform on the set of target objects. Management policies are then grouped into roles reflecting the organisation..