235,495 research outputs found

    Semantic Analysis of the Postscript Page Description Language

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    The Postscript page description language is a functional programming language. Central to the effective use of the language are the functional properties of delayed evaluation and referential transparency. Postscript performs all of its operations via distinct, multiple stacks which stores function binding lists, function parameters, and function code. By way of these stacks, Postscript creates dynamic computational states which leads identical expressions to evaluate to different results. This hints towards the polymorphic quality of an object-oriented language, even though it contradicts the functional precept of manifest interfaces thereby introducing a nonorthogonality. One other streak of object-orientation that shows up in Postscript is pointer semantics. Postscript\u27s graphics intentions are at the center of its slippery semantics and typeface and letter form rendering underpin Postscript\u27s data and execution model. Properties from both functional and object-oriented programming languages create Postscript\u27s robust font, graphics, and publishing abilities

    TEMPOS: A Platform for Developing Temporal Applications on Top of Object DBMS

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    This paper presents TEMPOS: a set of models and languages supporting the manipulation of temporal data on top of object DBMS. The proposed models exploit object-oriented technology to meet some important, yet traditionally neglected design criteria related to legacy code migration and representation independence. Two complementary ways for accessing temporal data are offered: a query language and a visual browser. The query language, namely TempOQL, is an extension of OQL supporting the manipulation of histories regardless of their representations, through fully composable functional operators. The visual browser offers operators that facilitate several time-related interactive navigation tasks, such as studying a snapshot of a collection of objects at a given instant, or detecting and examining changes within temporal attributes and relationships. TEMPOS models and languages have been formalized both at the syntactical and the semantical level and have been implemented on top of an object DBMS. The suitability of the proposals with regard to applications' requirements has been validated through concrete case studies

    Supporting the object-oriented database on the Kernel Database System

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    If a single operating system can support multitudes of different programming languages and data structures, a database system can support a variety of data models and data languages. In this thesis, a Kernel Database System (KDS) supporting classical data models and data languages (i.e., hierarchical, network, relational, and functional) is used to support a demonstration object oriented data model and data language. This thesis extends previous research by accommodating an object-oriented-data-model-and-language interface in the KDS. Consequently, the research shows that it is feasible to use the KDS to support modem data models and languages as well as classical ones. This thesis details the KDS design, Insert operation, and Display function. This thesis also details how to implement modifications to the Test-Interface so that the KDS can support the object-oriented database. This thesis proves complex data structures in an object-oriented data model can be realized using an attribute-based data model which is the kernel data model of the KDS. Second, it details how the KDS is designed showing why no changes needed to be made to the KDS to implement the object-oriented toy database. Third, it argues the advantages of using a KDS in the database-system design. The KDS design produces savings in costs from compatability, reduced training, expandability, and software reuse.http://archive.org/details/supportingobject1094535152NANAU.S. Navy (U.S.N.) author.;Korean Army author

    Functional and Object-Oriented Views in Embedded Software Modeling

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    The main aim of this article is to discuss how the functional and the object-oriented views can be inter-played in order to model the various modeling perspectives of an embedded system. We discuss if the object-oriented modeling paradigm, most likely the predominant one to develop nowadays software, in the broader sense of the term, is also adequate for modeling embedded software and how it must be conjugated with the functional paradigm. More specifically, we present how Data Flow Diagrams (DFDs), the main diagram in the traditional structured methods, can be integrated in an object-oriented development strategy based on the Unified Modeling Language (UML).CIMO - HH-02-383; Fundação para a Ciência e Tecnologia; Fundo Europeu de Desenvolvimento Regional - Project METHODES: Methodologies and Tools for Developing Complex Real-Time Embedded Systems (POSI/37334/CHS/2001)

    Object-oriented development

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    Object Oriented Development (OOD) is one of the extremely few software development methods actually designed for modern Ada language, real-time, embedded applications. OOD is a significant improvement over more traditional functional decomposition and modeling methods in that ODD: Better manages the size, complexity, and concurrancy of today's systems; Better addresses important software engineering principles such as abstract data types, levels of abstraction, and information hiding; Produces a better design that more closely matches reality; Produces more maintainable software by better localizing data and thus limiting the impact of requirements changes; and Specifically exploits the power of Ada. OOD is further explored in detail

    Integration of DFDs into a UML - based model-driven engineering approach

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    The main aim of this article is to discuss how the functional and the object-oriented views can be inter-played to represent the various modeling perspectives of embedded systems.We discuss whether the object-oriented modeling paradigm, the predominant one to develop software at the present time, is also adequate for modeling embedded software and how it can be used with the functional paradigm.More specifically, we present how the main modeling tool of the traditional structured methods, data flow diagrams, can be integrated in an object-oriented development strategy based on the unified modeling language. The rationale behind the approach is that both views are important for modeling purposes in embedded systems environments, and thus a combined and integrated model is not only useful, but also fundamental for developing complex systems. The approach was integrated in amodel-driven engineering process, where tool support for the models used was provided. In addition, model transformations have been specified and implemented to automate the process.We exemplify the approach with an IPv6 router case study.FEDER -Fundação para a Ciência e a Tecnologia(HH-02-383

    A CuCh Interpretation of an Object-Oriented Language1 1Partially supported by MURST Cofin '99 TOSCA.

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    AbstractBöhm's CuCh machine extends the pure lambda-calculus with algebraic data types and provides the possibility of defining functions over disjoint sums of algebras. We exploit such natural form of overloading to define a functional interpretation of a simple, but significant fragment of a typical objectoriented classbased language

    Transforming sequences using threaded morphisms.

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    Sequences are very useful structures in programming languages. Functional programming languages allow the convenient definition of transformations between sequence algebras and other types of data algebra. Sequence homomorphisms are an important class of such transformations. However, not all desired transformations can be expressed as homomorphisms. This paper describes a class of transformation which is a generalisation of homomorphisms: sequence morphisms with threads. This class is shown to contain a number of interesting sub-classes of transformation. The morphisms are described using a simple functional programming language and are applied to the design and implementation of a simple object-oriented programming language feature

    Protein Structure Data Management System

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    With advancement in the development of the new laboratory instruments and experimental techniques, the protein data has an explosive increasing rate. Therefore how to efficiently store, retrieve and modify protein data is becoming a challenging issue that most biological scientists have to face and solve. Traditional data models such as relational database lack of support for complex data types, which is a big issue for protein data application. Hence many scientists switch to the object-oriented databases since object-oriented nature of life science data perfectly matches the architecture of object-oriented databases, but there are still a lot of problems that need to be solved in order to apply OODB methodologies to manage protein data. One major problem is that the general-purpose OODBs do not have any built-in data types for biological research and built-in biological domain-specific functional operations. In this dissertation, we present an application system with built-in data types and built-in biological domain-specific functional operations that extends the Object-Oriented Database (OODB) system by adding domain-specific additional layers Protein-QL, Protein Algebra Architecture and Protein-OODB above OODB to manage protein structure data. This system is composed of three parts: 1) Client API to provide easy usage for different users. 2) Middleware including Protein-QL, Protein Algebra Architecture and Protein-OODB is designed to implement protein domain specific query language and optimize the complex queries, also it capsulates the details of the implementation such that users can easily understand and master Protein-QL. 3) Data Storage is used to store our protein data. This system is for protein domain, but it can be easily extended into other biological domains to build a bio-OODBMS. In this system, protein, primary, secondary, and tertiary structures are defined as internal data types to simplify the queries in Protein-QL such that the domain scientists can easily master the query language and formulate data requests, and EyeDB is used as the underlying OODB to communicate with Protein-OODB. In addition, protein data is usually stored as PDB format and PDB format is old, ambiguous, and inadequate, therefore, PDB data curation will be discussed in detail in the dissertation
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