Complex Schema Research Articles

Graceful database schema evolution

Supporting graceful schema evolution represents an unsolved problem for traditional information systems that is further exacerbated in web information systems, such as Wikipedia and public scientific databases: in these projects based on multiparty cooperation the frequency of database schema changes has increased while tolerance for downtimes has nearly disappeared. As of today, schema evolution remains an error-prone and time-consuming undertaking, because the DB Administrator (DBA) lacks the methods and tools needed to manage and automate this endeavor by (i) predicting and evaluating the effects of the proposed schema changes, (ii) rewriting queries and applications to operate on the new schema, and (iii) migrating the database. Our PRISM system takes a big first step toward addressing this pressing need by providing: (i) a language of Schema Modification Operators to express concisely complex schema changes, (ii) tools that allow the DBA to evaluate the effects of such changes, (iii) optimized translation of old queries to work on the new schema version, (iv) automatic data migration, and (v) full documentation of intervened changes as needed to support data provenance, database flash back, and historical queries. PRISM solves these problems by integrating recent theoretical advances on mapping composition and invertibility, into a design that also achieves usability and scalability. Wikipedia and its 170+ schema versions provided an invaluable testbed for validating PRISM tools and their ability to support legacy queries.

Learning Semantic Definitions of Online Information Sources

The Internet contains a very large number of information sources providing many types of data from weather forecasts to travel deals and financial information. These sources can be accessed via Web-forms, Web Services, RSS feeds and so on. In order to make automated use of these sources, we need to model them semantically, but writing semantic descriptions for Web Services is both tedious and error prone. In this paper we investigate the problem of automatically generating such models. We introduce a framework for learning Datalog definitions of Web sources. In order to learn these definitions, our system actively invokes the sources and compares the data they produce with that of known sources of information. It then performs an inductive logic search through the space of plausible source definitions in order to learn the best possible semantic model for each new source. In this paper we perform an empirical evaluation of the system using real-world Web sources. The evaluation demonstrates the effectiveness of the approach, showing that we can automatically learn complex models for real sources in reasonable time. We also compare our system with a complex schema matching system, showing that our approach can handle the kinds of problems tackled by the latter.

Matching large schemas: Approaches and evaluation

Current schema matching approaches still have to improve for large and complex Schemas. The large search space increases the likelihood for false matches as well as execution times. Further difficulties for Schema matching are posed by the high expressive power and versatility of modern schema languages, in particular user-defined types and classes, component reuse capabilities, and support for distributed schemas and namespaces. To better assist the user in matching complex schemas, we have developed a new generic schema matching tool, COMA++, providing a library of individual matchers and a flexible infrastructure to combine the matchers and refine their results. Different match strategies can be applied including a new scalable approach to identify context-dependent correspondences between schemas with shared elements and a fragment-based match approach which decomposes a large match task into smaller tasks. We conducted a comprehensive evaluation of the match strategies using large e-Business standard schemas. Besides providing helpful insights for future match implementations, the evaluation demonstrated the practicability of our system for matching large schemas.

Intervention in a 'Divided World': Axes of Legitimacy

In the post-2001 era, many fear that the 'international community' that had been developing in the years after the Cold War is becoming irremediably divided. Challenges to the 'international community' have come from such radically disparate quarters as US unilateralism and Islamicist attacks on 'Western' internationalism. Many worry that such divisions will severely hamper the ability of the international community to intervene in local crises, whether for humanitarian purposes or to stop ethnic conflict. This article challenges the major assumptions upon which this common view is based. First, it rejects the notion that the 'international community' ever had the kind of unity that is retrospectively attributed to it. Secondly, it rejects the notion that such an illusory unity is necessary for the legitimacy of international interventions even of the boldest variety. Rather, by examining recent fears in light of the history of bold international action since World War I, it develops a complex schema for evaluating forms of international legitimacy and forms of critique of that legitimacy. In light of this analysis, it shows how legitimacy can be achieved, even if only provisionally, even under the most fractious international conditions. In particular, it shows how the achievement of such legitimacy depends on distinguishing actions in the name of internationalism from seemingly similar actions that lie in international law's discredited colonial past.

Matching large XML schemas

Current schema matching approaches still have to improve for very large and complex schemas. Such schemas are increasingly written in the standard language W3C XML schema, especially in E-business applications. The high expressive power and versatility of this schema language, in particular its type system and support for distributed schemas and name-spaces, introduce new issues. In this paper, we study some of the important problems in matching such large XML schemas. We propose a fragment-oriented match approach to decompose a large match problem into several smaller ones and to reuse previous match results at the level of schema fragments.

Geoinformatics – An Integrated Spatial Research Tool

Abstract The structure of geoinformatics can be understood in many ways, what can be seen from the more or the less complex schemas published in various articles. Geoinformatics creates new possibilities for the precise analysis of spatial phenomena, such as for following their dynamics or defining the associations existing between their components. The use of remote sensing data in such research, takes to another level those areas of knowledge, in which there nevertheless still is a scarcity of reliable materials. It also enables the current monitoring of those phenomena which can’t be investigated and estimated in any other way, as well as the modeling of spatial (geographical) phenomena. Since 1996, many studies have been performed at the Laboratory of Remote Sensing of the Environment at the University of Warsaw, in which remote sensing data were integrated with data obtained by other means.

Component development and construction for database design

Principles for database modeling were developed and intensively investigated in the late 1970s and early 1980s. They are based on concepts such as supertypes and subtypes, restructuring through normalization, type construction by constructors, generic models, and associations with pre-specified semantic meaning, e.g., classified relationship types. Use of these principles can result in large and complex database schemas that are difficult for developers to understand, integrate, and extend. We observe that often such schemas consist of identifiable sub-schemas that are loosely coupled. We use this observation to develop a design theory aimed at component-based construction of schemata. Building blocks used for schema construction are termed kernel components. Kernel components are composed to form more complex components by the application of the component constructors. Our approach allows a developer to derive an understandable schema topography for very large and complex databases.

AN ONTOLOGY FOR SEMANTIC INTEGRATION OF LIFE SCIENCE WEB DATABASES

The incompatibilities among complex data formats and various schema used by biological databases that house these data are becoming a bottleneck in biological research. For example, biological data format varies from simple words (e.g. gene name), numbers (e.g. molecular weight) to sequence strings (e.g. nucleic acid sequence), to even more complex data formats such as taxonomy trees. Some information is embedded in narrative text, such as expert comments and publications. Some other information is expressed as graphs or images (e.g. pathways networks). The confederation of heterogeneous web databases has become a crucial issue in today's biological research. In other words, interoperability has to be archieved among the biological web databases and the heterogeneity of the web databases has to be resolved. This paper presents a biological ontology, BAO, and discusses its advantages in supporting the semantic integration of biological web databases are discussed.

Illness Schema and Level of Reported Gastrointestinal Symptoms in Irritable Bowel Syndrome

Twenty individuals with irritable bowel syndrome (IBS) completed a diary recording the severity of gastrointestinal symptoms over a period of 5 days. On one morning participants read cues intended to draw attention to IBS symptoms and the impact of symptoms on daily life (“illness context”). On another morning participants read cues intended to draw their attention to neutral aspects of symptoms (“neutral context”). On the 3 remaining days control cues were given. On the illness-context day, participants reported increases in the frequency of thoughts about IBS and in the range and severity of gastrointestinal symptoms compared with control conditions. On the neutral-context day participants reported lower levels of anxiety and perceived symptoms to be less severe than under control conditions. It is suggested that individuals with IBS interpret symptoms and illness-related experiences within a complex schema. As the salience of this illness schema increases, for example through rumination about IBS, sensations are increasingly likely to be detected and attributed to IBS. In contrast, attending to low-level features of symptoms may introduce a more neutral schema, resulting in less symptom-related anxiety and a more objective appraisal of the occurrence and severity of symptoms.

Mining the Metadata Quarries

It is a foregone conclusion that metadata describing digital resources in a globally networked environment will be a bedrock for the Semantic Web. The four articles in the special section of this issue of the Bulletin touch on a few of the threads in metadata research, development and deployment. While for many the notion of metadata is a simple one and hardly new, the proliferation in a globally networked environment of metadata schemas expressing the needs of discourse and practice communities as well as organizations throughout the private and public sectors taxes our understandings of semantic interoperability. Research and development cover many different areas including interoperability among complex schema and value spaces; application profiles that permit the wedding of metadata statements from disparate schemas through network-accessible schema registry services; and metadata support tools. In this issue we look at a sample of current work. Rebecca Guenther and Sally McCallum examine the rationale and the basic architecture of the Metadata Object and Description Schema (MODS) and the Metadata Encoding and Transmission Standard (METS). MODS is intended as a bridge between the descriptively rich MARC 21 metadata and terse metadata schema such as the Dublin Core Metadata Element Set. The authors describe the basic features of MODS, its prospective users and current experimentation in its use. METS is an XML-based schema that provides a means for packaging, or pointing to, descriptive, administrative, structural, rights and behavioral metadata for digital resources. METS supports the seamless flow of metadata and electronic resources between networked systems. Jane Greenberg's article defines a framework for identifying and examining processes of metadata generation, the tools required for that generation and the categories of metadata creators – human and automatic. In addition to providing class definitions for the various entities in her metadata generation framework, Greenberg provides references to examples of metadata generation tools and research and development projects. The article includes a brief description of the Metadata Generation Research Project at the University of North Carolina studying the entities in the framework and developing protocols for collaborations in its various processes. The final two articles focus on value space problems. Joseph Tennis describes a pilot study that explores the interoperability problem faced by multiple metadata projects making statements by means of disparate controlled vocabularies. The goal of the study is to test a methodology for developing a switching language using card sorts, cluster analysis and talk-aloud protocols. Wang Jun's article discusses the tools, architecture and the implementation of an experimental system to support knowledge management. He describes development of a concept network consisting of nodes and edges developed from the Chinese Classification and Thesaurus, an integrated product widely used in Chinese libraries, to which metadata records are bound. Research includes expanding and customizing the concept network using information from the titles from the bibliographic records. The test database is in computer science.

Is the self-organizing consciousness framework compatible with human deductive reasoning?

As stressed by Perruchet & Vinter, the SOC model echoes Johnson-Laird's mental model theory. Indeed, the latter rejects rule-based processing and assumes that reasoning is achieved through the manipulation of conscious representations. However, the mental model theory as well as its modified versions resorts to the abstraction of complex schemas and some form of implicit logic that seems incompatible with the SOC approach.

Cueing for Schema Construction: Designing Problem-Solving Multimedia Practicals

In competency-based learning environments, schemata play an important role in solving complex and authentic problems. Adequate task-valid cueing is considered to facilitate both recall and interpretation of available schemata (task performance) and the construction of new schemata (learning). This article provides guidelines for cueing which aim at the improvement of (1) task performance in complex learning environments, (2) schema construction, and (3) monitoring. A model presents the relationships between cueing on the one hand and schema interpretation, schema construction, and monitoring on the other hand. The guidelines are used to evaluate worked-out examples and process worksheets, two formats of task-valid cueing that appear useful in competency-based learning environments. Worked-out examples support the inductive processing of concrete descriptions to construct schemata, while process worksheets support the deduction of concrete problem solving steps from general prescriptions. Illustrations are provided from the domain of law.

The Boehner Centenary

278 Bo o k Revie w s reminder that in our western world of rampant materialism God still listens most attentively to the cry of the poor. Washington Theological Union ILIA DELIO, O.S.F. J. Schlageter, ed. Petri lohannis Olivi Expositio in Canticum Canticorum. Collectio Oliviana II. Grottaferrata (Rome), 1999. A. Ciceri, Petri lohannis Olivi Quaestiones Circa Matrimonium. Editio Prima Et Commentarius Theologicus. Collectio Oliviana III. Grottaferrata (Rome), 2001. Two editions of writings by Peter Olivi have recently been published— J. Schlageter, to whom we owe the edition of Olivi’s treatise on poverty (1989), and more recently in 1999 Olivi’s commentary on The Song of Songs. In the same year (1999), A. Ciceri supplied medievalists with a most useful tool by publishing as much data as he could gather on manuscripts with writings by Peter Olivi.1 He began his list when looking for manuscripts containing Olivi’s treatment of marriage. What he found he has now used to edit Olivi’s writings on marriage, along with a detailed commentary (2001). All three books have appeared in the series Collectio Oliviana, launched at the conclusion of the December 1997 conference on the writings of Peter Olivi.2 Schlageter sets up his edition of Olivi’s Song commentary by examining closely the ten manuscripts that have saved it from the ravages of time. His review of the material allows him to give a conclusive answer to the central question of its edition. A long and a short version of the text have come down to us. Moreover, the longer one, edited by B. Bonelli and ascribed to Bonaventure of Bagnoregio in the eighteenth century, has understandably received some attention. That is what existed as the commentary until now. Schlageter shows that Olivi wrote the shorter text, whereas the longer text arose later, with additions working their way into Olivi’s text in stages. Of the seven early manuscripts with the commentary, six have the shorter version, 'A. Ciceri, Petri lohannis Olivi Opera. Censimento dei manoscritti. Collectio Oliviana I. Grottaferrata (Rome), 1999. 2On that conference see Archivum Franciscanum Historicum Vol. 91, the JulyDecember issue. Bo o k Revie w s 279 whereas only one has the material of the longer version; and that one manuscript has some passages of the longer version still in its margins, not yet worked into the text. The longer version’s first full appearance is in a manuscript of the sixteenth century. Schlageter also shows that the additions proceed from a different reading of the Song. Whereas the additions are reflections inspired by the biblical text, Olivi focuses on the text itself, taking it as a tale of divine love. With that question settled, Schlageter proceeded to work out the text’s tradition and so define the contribution of the different manuscripts to the edition (79-90). He faced a highly contaminated history, which led him to a complex schema of the tradition and a sensitive ratio editionis (89-90). His apparatus displays the evidence relevant to the text’s edition and regularly footnotes the grounds for his choice of readings. Schlageter has added a new commentary to the growing body of Olivi’s edited exegesis. He has, as well, translated his edition into German. Before getting to the description of the manuscripts and the ratio for his edition, Schlageter offers an introduction to the commentary. He characterizes the commentary as textual and historical in the following sense. First, Olivi focuses on the text itself. He wants to understand what Solomon wrote. As Christian tradition since Origen has had it, Olivi insists that the text speaks about love of God in the language of human love. Working in that tradition, he traces the fine distinction between true human love, as we find it in the Song of Songs, and sinful sexuality, which we do not find in the text. Sexuality, created by God, leads us back to God, as is implied by the fact that marriage is a sacrament. The Holy Spirit has used a regal union to sing of divine love. In this sense, Olivi insists he is reading the text and not engaging in allegorical interpretation. Schlageter broaches the proposal that this...

Endocrinology of parturition.

Endocrinology of parturition.

Aesthetics and the Environment

This article presents a framework for understanding aesthetic experience, with special reference to the natural environment. The framework entails 2 broad perspectives. First, from a functional perspective, aesthetic experiences are analyzed in terms of biological, sociocultural, and psychological systems of behavior; succinctly stated, objects are experienced aesthetically if they activate cognitive representations of response patterns that do or did contribute to the survival or enhancement of the species, society, or the self. Second, from the perspective of mediating mechanisms, the cognitive processes that enable aesthetic experiences are examined. The mechanisms discussed range from simple sensory processes to the activation and transformation of complex schemas. To the extent that cognitive representations of behavioral systems are flexible and subject to elaboration and refinement, aesthetic experience is a creative, skillful act.

Facilitating complex Web queries through visual user interfaces and query relaxation

The World Wide Web can be viewed as a collection of multimedia documents in the form of HTML pages connected through hyperlinks. We have designed and implemented a Web query system, WebDB, to support more comprehensive database-like query functionalities. WebDB supports queries on not only document level information (e.g. title, URL, keywords) but also intra-document structures (e.g. tables, forms, and images) and inter-document linkage information (e.g. URLs and anchors) To provide higher usability for a system with such functionalities, we have designed a novel visual user interface, WebIFQ (Web In-Frame-Query), to assist users in specifying queries and visualizing query criteria including document metadata, structures, and linkage information. WebIFQ automatically generates corresponding query statements for WebDB. As a result, users are not required to be aware of underlying complex schema design and language syntax. WebDB supports automated query relaxation to include additional terms related by semantic or co-occurrence relationship. Alternatively, WebIFQ can facilitate users to reformulate queries perpetually in an interactive mode.

Verification and Transformation of Complex and Uncertain Conceptual Schemas

In database environment, it is necessary to represent complex and uncertain information at conceptual level and then transform the conceptual schema into the logical one for ultimate implementation. It is also important to verify the conceptual schema with respect to the constraints imposed on the schema definition. In this paper we primarily focus on the verification and transformation of the conceptual schema. For the purpose of verification of the conceptual schema represented by the ExIFO data model (the extension of the IFO data model), we introduce a number of invariants. We also describe the transformation algorithm for mapping the conceptual specification into a logical database schema represented with the extended NF 2 database model. The system that we describe in this paper is implemented and it can test whether the given ExIFO specification is valid and transforms the conceptual specification into the logical schema. The transformation algorithm is computationally efficient and preserves the knowledge represented with verified conceptual schema.

The great deceiver: the role of convulsive syncope in the history of epilepsy

Because of its high medical and social profile, epilepsy has a voluminous documented history. For centuries it has been the subject of much speculation and attempted explanation. Even from antiquity examples taken from every day life have been used to explore, by analogy, the mechanism of epileptic seizures; and the convulsive phenomena of acute exsanguination have attracted much attention for this reason. A survey of the aspects and the consequences of this exercise in the study of seizure mechanisms shows that, until Jackson and Gowers emphasised the central role of the cortex in human epilepsy, a very complex schema had been constructed to explain epilepsy. This had been based upon erroneous information obtained by analogy from the convulsive phenomena of syncope and exsanguination. Over the millennia this mistaken concept served to divert scientific endeavour in attempts to explain and unravel the bases of epilepsy. It was only little more than a century ago that this concept was finally abandoned.

Generic data modeling for clinical repositories.

To construct a large-scale clinical repository that accurately captures a detailed understanding of the data vital to the process of health care and that provides highly efficient access to patient information for the users of a clinical information system. Conventional approaches to data modeling encourage the development of a highly specific data schema in order to capture as much information as possible about a given domain. In contrast, current database technology functions most effectively for clinical databases when a generic data schema is used. The technique of "generic data modeling" is presented as a method of reconciling these opposing views of clinical data, using formal operations to transform a detailed schema into a generic one. A complex schema consisting of hundreds of entities and representing a rich set of constraints about the patient care domain is transformed into a generic schema consisting of roughly two dozen tables. The resulting database design is efficient for patient-oriented queries and is highly flexible in adapting to the changing information needs of a health care institution, particularly changes involving the collection of new data elements. Conventional approaches to data modeling can be used to develop rich, complex models of clinical data that are useful for understanding and managing the process of patient care. Generic data modeling techniques can successfully transform a detailed design into an efficient generic design that is flexible enough to meet the needs of an operational clinical information system.

Schema equivalence in heterogeneous systems: Bridging theory and practice

Current theoretical work offers measures of schema equivalence based on the information capacity of schemas. This work is based on the existence of abstract functions satisfying various restrictions between the sets of all instances of two schemas. In considering schemas that arise in practice, however, it is not clear how to reason about the existence of such abstract functions. Further, these notions of equivalence tend to be too liberal in that schemas are often considered equivalent when a practitioner would consider them to be different. As a result, practical integration methodologies have not utilized this theoretical foundation and most of them have relied on ad-hoc approaches. We present results that seek to bridge this gap. First, we consider the problem of deciding information capacity equivalence and dominance of schemas that occur in practice, i.e., those that can express inheritance and simple integrity constraints. We show that this problem is undecidable. This undecidability suggests that in addition to the overly liberal nature of information capacity equivalence, we should look for alternative, more restrictive notions of equivalence that can be effectively tested. To this end, we develop several tests that each serve as sufficient conditions for information capacity equivalence or dominance. Each test is characterized by a set of schema transformations in the following sense: a test declares that Schema S1 is dominated by schema S2 if and only if there is a sequence of transformations that converts S1 to S2. Thus, each test can be understood essentially by understanding the individual transformations used to characterize it. Each of the transformations we consider is a local, structural schema change with a clear underlying intuition. We demonstrate the power of these tests by showing that one can reason about the equivalence and dominance of quite complex schemas. Because our work is based on structural transformations, the same characterizations that underly our tests can be used to guide designers in modifying a schema to meet their equivalence or dominance goals.