Reducing the search space for conceptual schema transformation

In this paper we focus on the transformation of a conceptual schema into an internal schema. For a given conceptual schema, quite a number of internal schemata can be derived. This number can be reduced by imposing restrictions on internal schemata.

We present a transformation algorithm that can generate internal schemata of several types (including the relational model and the NF² model). Guidance parameters are used to impose further restrictions.

We harmonise the different types of schemata by extending the conceptual language, such that both the conceptual and the internal models can be represented within the same language.     

Tools for designing conceptual schemata of databases

CSDL, a language for designing conceptual schemata, is described. The language provides tools to ease the translation of knowledge about data into a formal conceptual schema.     

Verification of conceptual schemata based on hybrid object-oriented and logic paradigm

Contemporary conceptual modelling languages are concerned with the representational adequacy of knowledge about a universe of discourse and with the efficient organization of this knowledge in structures that help overcome the problems of size and complexity in the modelled reality. In the paper it is argued that a conceptual modelling language should also facilitate the verification of captured requirements by exercising the conceptual schemata derived from the use of such a language. A conceptual modelling language is presented that is based on a hybrid representation scheme that makes use of object-oriented and logic approaches, and it is shown how this language can be used to verify requirements during the development of information systems.     

Schema design and mapping strategies for persistent object models

A formal model is presented for a conceptual schema of persistent object models that support a strong notion of object identity. The object constructors in the model are sets, tuples, and disjunct. The databases that correspond to such schemata are graph-structured object spaces. These conceptual object spaces are mapped onto physical object spaces, which are typically forests of trees. The characteristics of the physical schemata are discussed and an algorithm to transform a conceptual schema into a physical schema is given.     

Managing complexity in massively parallel, adaptive, multiphysics applications

A new generation of scientific and engineering applications are being developed to support multiple coupled physics, adaptive meshes, and scaling in massively parallel environments. The capabilities required to support multiphysics, adaptivity, and massively parallel execution are individually complex and are especially challenging to integrate within a single application. Sandia National Laboratories has managed this challenge by consolidating these complex physics-independent capabilities into the Sierra Framework which is shared among a diverse set of application codes. The success of the Sierra Framework has been predicated on managing the integration of complex capabilities through a conceptual model based upon formal mathematical abstractions. Set theory is used to express and analyze the data structures, operations, and interactions of these complex capabilities. This mathematically based, conceptual modeling approach to managing complexity is not specific to the Sierra Framework—it is generally applicable to any scientific and engineering application framework.     

Repository support for multi-perspective requirements engineering

Relationships among different modeling perspectives have been systematically investigated focusing either on given notations (e.g. UML) or on domain reference models (e.g. ARIS/SAP). In contrast, many successful informal methods for business analysis and requirements engineering (e.g. JAD) emphasize team negotiation, goal orientation and flexibility of modeling notations. This paper addresses the question how much formal and computerized support can be provided in such settings without destroying their creative tenor. Our solution is based on a novel modeling language, M-Telos, that integrates the adaptability and analysis advantages of the logic-based meta modeling language Telos with a module concept covering the structuring mechanisms of scalable software architectures. It comprises four components: (1) A modular conceptual modeling formalism organizes individual perspectives and their interrelationships. (2) Perspective schemata are linked to a conceptual meta meta model of shared domain terms, thus giving the architecture a semantic meaning and enabling adaptability and extensibility of the network of perspectives. (3) Inconsistency management across perspectives is handled in a goal-oriented manner, by formalizing analysis goals as meta rules which are automatically customized to perspective schemata. (4) Continuous incremental maintenance of inconsistency information is provided by exploiting recent view maintenance techniques from deductive databases. The approach has been implemented as an extension to the ConceptBase³ meta database management system and has been applied in a number of real-world requirements engineering projects.     

Deriving static and dynamic concepts from software requirements using sophisticated tagging

Natural language requirements specifications form the basis for the subsequent phase of the information system development process, namely the development of conceptual schemata. Both, the textual as well as the conceptual representations are not really appropriate for being thoroughly captured and validated by the ‘requirement holders’, i.e. the end users. Therefore, in our approach the textual specifications are firstly linguistically analyzed and translated into a so-called conceptual predesign schema. That schema is formulated using an interlingua which is based on a lean semantic model, thus allowing users to participate more efficiently in the design and validation process. After validation, the predesign schema is mapped to a conceptual representation (e.g. UML). The sequence of these translation and transformation steps is described by the “NIBA workflow”. This paper focuses on the information supporting a step by step mapping of natural language requirements specifications to a conceptual model, and on how that information is gained. On particular, we present a four-level interpretation of tagging-output.     

XSD: A Hierarchical Access Method for Indexing XML Schemata

Search operations and browsing facilities over an XML document database require special support at the physical level. Typical search operations involve path queries. This paper proposes a hierarchical access method to support such operations and to facilitate browsing. It advocates the idea of searching large XML collections by administering efficiently XML schemata. The proposed approach may be used for indexing XML documents according to their structural proximity. This is obtained by organizing the schemata of a large XML document collection in a hierarchical way by merging structurally close schemata. The proposed structure, which is called XML Schema Directory (XSD), is a balanced tree and it may serve two purposes: (1) to accelerate XML query processing and (2) to facilitate browsing. Received 15 March 2001 / Revised 12 April 2001 / Accepted in revised form 11 May 2001     

A Methodology for Data Schema Integration in the Entity Relationship Model

The conceptual design of databases is usually seen as divided into two steps: view modeling, during which user requirements are formally expressed by means of several user oriented conceptual schemata, and schema integration, whose goal is to merge such schemata into a unique global conceptual schema. This paper is devoted to describe a methodology for schema integration. An enriched entity relationship model is chosen as the data model. The integration process consists of three steps: first, several types of conflicts between the different user schemata are checked and solved; second, schemata are merged into a draft integrated schema, that is, third, enriched and restructured according to specific goals.     

Conceptual design, manufacturability evaluation and preliminary process planning using function-form relationships in stamped metal parts

A large number of design decisions are made during the conceptual design of a part. However, there are few representation and reasoning tools for decision support during conceptual design. The conceptual design stage is characterized by a lack of complete geometric information. Existing geometric modelers require complete geometric information, while a functional reasoning methodology using a <verb, noun > representation is typically too terse. In this paper, we present a new representation called sketching abstraction for conceptual design, using the function-form relations in a design. The functionally critical part of the geometry is presented using a set of functional features, while the rest of the geometry is abstracted as a set of linkages. Part functionality is correlated with the sketching abstraction using data structures called function-form matrices. The sketching abstraction is annotated using a set of primitives, and a set of grammar rules are used to extract canonical relationships between the functional features. The sketching abstraction can be used for extracting designs that are geometrically dissimilar but functionally similar, thus providing the designer with ideas for design alternatives. The sketching abstraction can also be used to carry out domain-dependent manufacturability evaluation checks. A further use of sketching abstractions is to initiate the development of a process plan for manufacturing. Sketching abstractions are related to the solid model of a part. Thus, this representation provides a link between pure functional and pure geometric representations. The domain of application is stamped metal parts. We present the part functionality and the features used in this domain. We also illustrate the use of sketching abstractions for conceptual design, manufacturability evaluation and preliminary process planning.     

A reference model of virtual service production networks

Virtual organisation of collaborative networks frequently demands for information and communication technology to support coordination of cross-organisational business process chains. Service-oriented software technologies provide promising means to regulate and enforce coordination of cross-organisational software service interactions but miss organisational abstractions and methodology. This paper proposes a conceptual reference model of collaborative network coordination that satisfies flexibility and agility requirements of virtual organisation by building on common software service abstractions and lifecycle methodology. In particular, the model focuses collaborative service networks and introduces the concept of virtual business service that represents business service processes as software service abstractions and supports flexible regulation and agile enforcement of their coordination by means of software service lifecycle methodology. For demonstration and evaluation purpose, we present a case study of service-oriented systems analysis for virtual organisation of a collaborative e-science network that adopts our conceptual reference model.     

Knowledge-intensive natural language generation

The development of natural language interfaces to artificial intelligence systems is dependent on the representation of knowledge. A major impediment to building such systems has been the difficulty in adding sufficient linguistic and conceptual knowledge to extend and adapt their capabilities. This difficulty has been apparent in systems that perform the task of language production, i.e., the generation of natural language output to satisfy the communicative requirements of a system.A uniform, parsimonious representation of knowledge about language can increase extensibility and efficiency as well as simplify the generation process. The Ace framework applies knowledge representation fundamentals to the task of encoding knowledge about language. Within this framework, linguistic and conceptual knowledge are organized into hierarchies, and structured associations are used to join knowledge structures that are metaphorically related or otherwise used in linguistic expression. These structured associations permit specialized linguistic knowledge to derive partially from more abstract knowledge, facilitating the use of abstractions in generating specialized phrases. A simple generator called KING (Knowledge INtensive Generator) uses an Ace knowledge base to produce utterances from their conceptual representation.     

MultiArray: a C++ library for generic programming with arrays

In C++, multi‐dimensional arrays are often used but the language provides limited native support for them. The language, in its Standard Library, supplies sophisticated interfaces for manipulating sequential data, but relies on its bare‐bones C heritage for arrays. The MultiArray library, a part of the Boost library collection, enhances a C++ programmer's tool set with versatile multi‐dimensional array abstractions. It includes a general array class template and native array adaptors that support idiomatic array operations and interoperate with C++ Standard Library containers and algorithms. The arrays share a common interface, expressed as a generic programming concept, in terms of which generic array algorithms can be implemented. We present the library design, introduce a generic interface for array programming, demonstrate how the arrays integrate with the C++ Standard Library, and discuss the essential aspects of their implementation. Copyright © 2004 John Wiley & Sons, Ltd.     

Towards a cognitive foundation for knowledge representation

Abstract. Knowledge engineering, knowledge management and conceptual modelling are concerned with representing knowledge of business and organizational domains. These research areas use ontologies for knowledge representation. Ontologies are understood either in the philosophical sense as firm metaphysical commitments or in the looser sense of dictionaries or taxonomies.
This paper critically examines the understanding and use of ontologies and knowledge representation languages in information systems (IS) research and application. As ontologies are intended to be conceptualizations of a perceived reality, they should reflect the empirically observed reality. This motivates proposing psychology of language as a reference discipline for knowledge engineering and knowledge management. Natural language is argued to reflect the cognitive concepts we use to think about and perceive the world around us. These cognitive concepts are the relevant terms with which to structure and represent knowledge about the world.
Psychology of language can provide empirical justification for a particular set of concepts to represent knowledge. This paper draws on psycho-linguistic research to develop a proposal for a system of cognitive structures. This is argued to provide the relevant concepts on which to found knowledge representation schemata for knowledge engineering, knowledge management and conceptual modelling.     

Capture, integration, and analysis of digital system requirementswith conceptual graphs

Initial requirements for new digital systems and products that are generally expressed in a variety of notations including diagrams and natural language can be automatically translated to a common knowledge representation for integration, for consistency and completeness analysis, and for further automatic synthesis. Block diagrams, flowcharts, timing diagrams, and English as used in specifying digital systems requirements are considered as examples of source notations for system requirements. The knowledge representation selected for this work is a form of semantic network called conceptual graphs. For each source notation, a basis set or semantic primitives in terms of conceptual graphs is given, together with an algorithm for automatically generating conceptual structures from the notation. The automatic generation of conceptual structures from English presumes a restricted sublanguage of English and feedback to the author for verification of the interpretation. Mechanisms for integrating the separate conceptual structures generated from individual requirements expressions using schemata are discussed, and methods are illustrated for consistency and completeness analysis     

Extending type systems in a library: Type-safe XML processing in C++

Type systems built directly into the compiler or interpreter of a programming language cannot be easily extended to keep track of run-time invariants of new abstractions. Yet, programming with domain-specific abstractions could benefit from additional static checking. This paper presents library techniques for extending the type system of C++ to support domain-specific abstractions. The main contribution is a programmable “subtype” relation. As a demonstration of the techniques, we implement a type system for defining type qualifiers in C++, as well as a type system for the XML processing language, capable of, e.g., statically guaranteeing that a program only produces valid XML documents according to a given XML schema.     

数据源集成系统中动态字典构造方法研究

本文从异构数据源集成系统的角度出发,引入模板和动态字典的概念,统一描述各种数据源数据的模式。动态字典不仅能描述对象的结构特征,还能描述对象的行为特征,完全符合面向对象特点。除此以外,本文还引入五种模板操作的定义,并证明ＯＩＭ对象操作的模板可由相应的模板操作构成,从而给出不通过扫描数据库,而是利用局部动态字典的模板操作构造集成系统全局动态字典的方法。     

A CASE tool for conceptual database design

The paper describes a Computer Aided Software Engineering (CASE) tool to support conceptual database modelling. One popular approach for conceptual database modelling is use of the Entity-Relationship (ER) model. The paper proposes the use of an Enhanced Entity-Relationship (EER) model for conceptual database modelling. This Enhanced Entity-Relationship model extends the Entity-Relationship model by incorporating the generalization/specialization, aggregation and categorization abstractions. The CASE tool, which is based on the Enhanced Entity-Relationship model, is known as the Enhanced Entity-Relationship Diagrammer (EERD). In addition, the CASE tool supports direct visual query and update based on the EERM.     

Directly reflective meta-programming

Existing meta-programming languages operate on encodings of programs as data. This paper presents a new meta-programming language, based on an untyped lambda calculus, in which structurally reflective programming is supported directly, without any encoding. The language features call-by-value and call-by-name lambda abstractions, as well as novel reflective features enabling the intensional manipulation of arbitrary program terms. The language is scope safe, in the sense that variables can neither be captured nor escape their scopes. The expressiveness of the language is demonstrated by showing how to implement quotation and evaluation operations, as proposed by Wand. The language’s utility for meta-programming is further demonstrated through additional representative examples. A prototype implementation is described and evaluated.