698 research outputs found

    Query processing of geometric objects with free form boundarie sin spatial databases

    Get PDF
    The increasing demand for the use of database systems as an integrating factor in CAD/CAM applications has necessitated the development of database systems with appropriate modelling and retrieval capabilities. One essential problem is the treatment of geometric data which has led to the development of spatial databases. Unfortunately, most proposals only deal with simple geometric objects like multidimensional points and rectangles. On the other hand, there has been a rapid development in the field of representing geometric objects with free form curves or surfaces, initiated by engineering applications such as mechanical engineering, aviation or astronautics. Therefore, we propose a concept for the realization of spatial retrieval operations on geometric objects with free form boundaries, such as B-spline or Bezier curves, which can easily be integrated in a database management system. The key concept is the encapsulation of geometric operations in a so-called query processor. First, this enables the definition of an interface allowing the integration into the data model and the definition of the query language of a database system for complex objects. Second, the approach allows the use of an arbitrary representation of the geometric objects. After a short description of the query processor, we propose some representations for free form objects determined by B-spline or Bezier curves. The goal of efficient query processing in a database environment is achieved using a combination of decomposition techniques and spatial access methods. Finally, we present some experimental results indicating that the performance of decomposition techniques is clearly superior to traditional query processing strategies for geometric objects with free form boundaries

    Object-oriented querying of existing relational databases

    Get PDF
    In this paper, we present algorithms which allow an object-oriented querying of existing relational databases. Our goal is to provide an improved query interface for relational systems with better query facilities than SQL. This seems to be very important since, in real world applications, relational systems are most commonly used and their dominance will remain in the near future. To overcome the drawbacks of relational systems, especially the poor query facilities of SQL, we propose a schema transformation and a query translation algorithm. The schema transformation algorithm uses additional semantic information to enhance the relational schema and transform it into a corresponding object-oriented schema. If the additional semantic information can be deducted from an underlying entity-relationship design schema, the schema transformation may be done fully automatically. To query the created object-oriented schema, we use the Structured Object Query Language (SOQL) which provides declarative query facilities on objects. SOQL queries using the created object-oriented schema are much shorter, easier to write and understand and more intuitive than corresponding S Q L queries leading to an enhanced usability and an improved querying of the database. The query translation algorithm automatically translates SOQL queries into equivalent SQL queries for the original relational schema

    University of Helsinki Department of Computer Science Annual Report 1998

    Get PDF

    Menopause and its management the physiopathologic foundation

    Get PDF
    An historical survey of all issues relating to the menopause was considered integral to understanding attitudes and the existing state of knowledge at the time of my planning and designing my initial investigations. While the research literature up to late 1966 was essentially narrative in nature, there were many indirect areas of research that could help define both the level of existing knowledge as well as attitudes and perceptions at that time. Above all, by understanding and documenting a comprehensive historical survey, it became possible to define the pertinent questions that needed answers. Key papers in which I documented the history and summarized the state of the art at that time are references 1-5, 107, 109, and my monograph, “Menopause in Modern Perspective (Appleton, Century, Crofts, New York, 1979). I can best summarize the background to my future studies by quoting from my first published analysis of the literature in 1968.107 The critical review opened with the observation that “most of what is published is based on emotional and philosophical premises; the 'change of life' is an emotional subject not only to women, but to men and doctors.” The purpose of the review was then listed as: “1. To analyse the current thoughts regarding the menopause. 2. To draw attention to the paucity of authoritative research and published data. 3. To serve as an indication for the urgent need for research, particularly into the nature of the menopause and the methods for the relief of menopausal symptoms and disorders; the process of 'ageing' and, in particular, the occurrence of osteoporosis and atherosclerosis in postmenopausal women; and the metabolic and vascular changes following acute hormone withdrawal, e.g. after bilateral oophorectomy in the pre- and postmenopausal female.” The conclusions of that 1968 critical review determined my future career path: “Several questions urgently require answers: 1. Is the climacteric a normal physiologic stage in the life of the human female, or is it a simple result of ovarian failure and oestrogen deficiency? 2. Are the manifestations of ageing directly related to diminution of circulating sex hormones? 3. Can the administration of exogenous oestrogen or other sex hormones prevent the manifestations of ageing? 4. Are the oestrogens at present available for administration equivalent in effect to circulating endogenous oestrogens? 5. Does long-term oestrogen administration result in an increased incidence of breast or uterine carcinoma? 6. Do oestrogens have a direct effect on the psychological state and sense of well-being in the postmenopausal patient? To these ends the development of more precise diagnostic techniques and methods of evaluation is vital

    Interim research assessment 2003-2005 - Computer Science

    Get PDF
    This report primarily serves as a source of information for the 2007 Interim Research Assessment Committee for Computer Science at the three technical universities in the Netherlands. The report also provides information for others interested in our research activities

    Learning Ontology Relations by Combining Corpus-Based Techniques and Reasoning on Data from Semantic Web Sources

    Get PDF
    The manual construction of formal domain conceptualizations (ontologies) is labor-intensive. Ontology learning, by contrast, provides (semi-)automatic ontology generation from input data such as domain text. This thesis proposes a novel approach for learning labels of non-taxonomic ontology relations. It combines corpus-based techniques with reasoning on Semantic Web data. Corpus-based methods apply vector space similarity of verbs co-occurring with labeled and unlabeled relations to calculate relation label suggestions from a set of candidates. A meta ontology in combination with Semantic Web sources such as DBpedia and OpenCyc allows reasoning to improve the suggested labels. An extensive formal evaluation demonstrates the superior accuracy of the presented hybrid approach

    PERSONALISING INFORMATION SECURITY EDUCATION

    Get PDF
    Whilst technological solutions go a long way in providing protection for users online, it has been long understood that the individual also plays a pivotal role. Even with the best of protection, an ill-informed person can effectively remove any protection the control might provide. Information security awareness is therefore imperative to ensure a population is well educated with respect to the threats that exist to one’s electronic information, and how to better protect oneself. Current information security awareness strategies are arguably lacking in their ability to provide a robust and personalised approach to educating users, opting for a blanket, one-size-fits-all solution. This research focuses upon achieving a better understanding of the information security awareness domain; appreciating the requirements such a system would need; and importantly, drawing upon established learning paradigms in seeking to design an effective personalised information security education. A survey was undertaken to better understand how people currently learn about information security. It focussed primarily upon employees of organisations, but also examined the relationship between work and home environments and security practice. The survey also focussed upon understanding how people learn and their preferences for styles of learning. The results established that some good work was being undertaken by organisations in terms of security awareness, and that respondents benefited from such training – both in their workplace and also at home – with a positive relationship between learning at the workplace and practise at home. The survey highlighted one key aspect for both the training provided and the respondents’ preference for learning styles. It varies. It is also clear, that it was difficult to establish the effectiveness of such training and the impact upon practice. The research, after establishing experimentally that personalised learning was a viable approach, proceeded to develop a model for information security awareness that utilised the already successful field of pedagogy and individualised learning. The resulting novel framework “Personalising Information Security Education (PISE)” is proposed. The framework is a holistic approach to solving the problem of information security awareness that can be applied both in the workplace environment and as a tool for the general public. It does not focus upon what is taught, but rather, puts into place the processes to enable an individual to develop their own information security personalised learning plan and to measure their progress through the learning experience.Ministry Of Higher Education Malaysi

    Upowszechnianie wyników badań naukowych w międzynarodowych bazach danych : analiza biometryczna na przykładzie nauk technicznych, ze szczególnym uwzględnieniem elektrotechniki

    Get PDF
    The issues of bibliometrics, scientometrics, informetrics and webometrics have an important place among research subject undertaken by Polish and foreign scholars. Initially, these notions were used only by researchers in the fields of library science, scientometrics and information science. However, at the turn of the 20th and 21st centuries, quantitative methods became a fundamental tool for evaluation of, among others, sources of academic communication, academic research, research and academic centers. One of the elements of the evaluation is a quantitative analysis of academic publications in databases with international access. It is of particular importance in the case of technical sciences. This work is an attempt at a quantitative analysis of publications by Polish authors (affiliated to Polish technical universities) and Polish journals on electrotechnics in international databases. The contents are organized into four chapters with an introduction, conclusions, bibliography, name index and a list of figures and illustrations. Chapters one and two are devoted to theoretical issues, whereas chapters three and four – to practical issues. In the first chapter, selected issues concerning quantitative methods were presented, including an analysis of literature and a discussion over terminology carried out in book publications and journals. Moreover, selected examples of research conducted with the use of quantitative methods (including rankings and scientific reports) were discussed in this chapter). In chapter two, sources of information on academic publications, their origins and development (from bibliographic bases to citation indexes) were presented. A separate subchapter was devoted to databases of academic publications created by libraries of technical universities, and to indicators in the assessment of academic publications. Chapter three deals with electrotechnics as a field of science. An analysis was conducted with regard to the place of electrotechnics in science classifications based on selected examples, and the development of the teaching of electrotechnics at university level was shown. In this chapter, early and contemporary Polish journals on electrotechnics were presented, including journals published by technical universities themselves. Chapter four contains the results of an analysis of international databases (Scopus, WoS, CC), focusing on the representation of Polish journals, including their citations, and publications of authors with affiliation to Polish technical universities. Final conclusions of research and analyses have brought an answer to questions raised with regard to the assessment of representation in international databases of publications by Polish authors affiliated to Polish technical universities (in its various aspects, e.g., a publication type, language of publication, publication dynamics taking into account years of publications, cooperation with representatives of other European and non-European countries), and of Polish journals
    • …
    corecore