There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Data Mining - Concepts and Techniques.

Schema matching is a basic problem in many database application domains, such as data integration, E-business, data warehousing, and semantic query processing. In current implementations, schema matching is typically performed manually, which has significant limitations. On the other hand, previous research papers have proposed many techniques to achieve a partial automation of the match operation for specific application domains. We present a taxonomy that covers many of these existing approaches, and we describe the approaches in some detail. In particular, we distinguish between schema-level and instance-level, element-level and structure-level, and language-based and constraint-based matchers. Based on our classification we review some previous match implementations thereby indicating which part of the solution space they cover. We intend our taxonomy and review of past work to be useful when comparing different approaches to schema matching, when developing a new match algorithm, and when implementing a schema matching component.

/pdf/a-survey-of-approaches-to-automatic-schema-matching-4n2e5qtrpt.pdf

A survey of approaches to automatic schema matching

Ontologies tend to be found everywhere. They are viewed as the silver bullet for many applications, such as database integration, peer-to-peer systems, e-commerce, semantic web services, or social networks. However, in open or evolving systems, such as the semantic web, different parties would, in general, adopt different ontologies. Thus, merely using ontologies, like using XML, does not reduce heterogeneity: it just raises heterogeneity problems to a higher level. Euzenat and Shvaikos book is devoted to ontology matching as a solution to the semantic heterogeneity problem faced by computer systems. Ontology matching aims at finding correspondences between semantically related entities of different ontologies. These correspondences may stand for equivalence as well as other relations, such as consequence, subsumption, or disjointness, between ontology entities. Many different matching solutions have been proposed so far from various viewpoints, e.g., databases, information systems, and artificial intelligence. The second edition of Ontology Matching has been thoroughly revised and updated to reflect the most recent advances in this quickly developing area, which resulted in more than 150 pages of new content. In particular, the book includes a new chapter dedicated to the methodology for performing ontology matching. It also covers emerging topics, such as data interlinking, ontology partitioning and pruning, context-based matching, matcher tuning, alignment debugging, and user involvement in matching, to mention a few. More than 100 state-of-the-art matching systems and frameworks were reviewed. With Ontology Matching, researchers and practitioners will find a reference book that presents currently available work in a uniform framework. In particular, the work and the techniques presented in this book can be equally applied to database schema matching, catalog integration, XML schema matching and other related problems. The objectives of the book include presenting (i) the state of the art and (ii) the latest research results in ontology matching by providing a systematic and detailed account of matching techniques and matching systems from theoretical, practical and application perspectives.

Ontology Matching

A federated database system (FDBS) is a collection of cooperating database systems that are autonomous and possibly heterogeneous. In this paper, we define a reference architecture for distributed database management systems from system and schema viewpoints and show how various FDBS architectures can be developed. We then define a methodology for developing one of the popular architectures of an FDBS. Finally, we discuss critical issues related to developing and operating an FDBS.

Federated database systems for managing distributed, heterogeneous, and autonomous databases

Recently, wireless sensor networks have improved for many applications aimed at collecting information. However wireless sensor networks have many challenges to be solved. One of the most critical problems is the energy restriction. Therefore in order to extend the lifetime of sensor nodes, we need to minimize the amount of energy consumption. In many cases, sensor networks use routing schemes based on the tree routing structure. But when we collect information from a restricted area within the sensor field using the tree routing structure, the information is often assembled by sensor nodes located on different tree branches. In this case unnecessary energy consumption happens in ancestor nodes located out of the target area. In this paper, we propose the Sensor Network Subtree Merge algorithm, called SNSM, which uses the union of disjoint set forest algorithm for preventing unnecessary energy consumption in ancestor nodes for routing. SNSM algorithm has 3-phases: first finding the disjoint set of the subtree in the sensor field; second connecting each disjoint subtree with the closest node; and third virtually disconnect the subtree connected to new tree branch from previous tree structure. In the simulation, we apply SNSM algorithm to a minimum spanning tree structure. Simulation results show that SNSM algorithm reduces the energy consumption. Especially, SNSM is more efficient as number of sensor nodes in a sensor field increases.

Reducing Energy Consumption through the Union of Disjoint Set Forests Algorithm in Sensor Networks

Emerging e-commerce applications typically use a Web server and CGI (Common Gateway Interface)for data processing. This client/server architecture is suitable when the Internet is not congested and the database server is not overloaded, but it may cause problems if congestion and overloading occur. A certain class of DPS (Data Processing System) applications, such as order processing or sales reporting, do not require real-time response, so they may utilize email (Simple Mail Transport Protocol) or other protocols that allow delaying or relaying of data. In this paper, we propose an innovative model of DPS (the Senddata System) that avoids congestion on the Internet and exploits a database server around the clock. Our model provides easy access to the database server and fits naturally in the middle tier of the three-tier model for database access, while providing performance and security. E-commerce applications may use our model in the presence of congestion on the Internet or unavailability of the server.

ADTP: a new protocol for data processing over the internet

In bioinformatics research, scientists usually face the problems of modeling complex data types and integrating diverse resources. Traditional data models such as EER lack the expressing power to capture many characteristics that are common in bioinformatics data. We first propose extensions to the ER model that allow accurate representation of many of these characteristics. We then utilize these concepts in an integrative system to provide an easy-to-use interface for biologists to construct queries. Our research utilizes the enhanced conceptual modeling concepts to create a prototype mediator for querying multiple data sources. The various relationships between different biological entities are all semantically represented as domain ontologies stored in the mediator for experts to analyze and correlate the integrated query results. The following research has been conducted: (1) We first propose new EER schema notation to represent the common occurring biological concepts: the ordering properties of the DNA sequences, the 3D structure of proteins and the functional processes of metabolic pathways. (2) Then, we utilize these new relationships in the development of the mediated domain ontology, which helps the interface design and query processor implementation of our mediator system. 
Our mediated schema features are based on a hybrid of taxonomy ontologies (core concepts and external classification/annotation concepts) for interpretation of raw data sets (protein and gene sequences) in the context of molecular interactions, biochemical pathways and biological processes. We adopt the RDF data model to implement the mediation data. Our mediator mainly takes a browsing-based approach to integrate different data sources. Extra data can be dynamically retrieved through the web service. By browsing the ontology tree in the query interface, users can select concepts of interest and associated attributes to formulate queries based on their domain knowledge. The query result is a set of various database entry accessions with associated attribute values. Users can click each link of the accessions to see the detailed reports, or cross-compare attributes of these data instances. Query usability and performance experiments are tested for real data sets from UniProt [30], ENZYME [8], CATH [23], and GO [29].

Enhanced bioinformatics data modeling concepts and their use in querying and integration

OpenGIS SQL is a standard for incorporating GIS and spatial concepts into SQL. Two types of methods are part of OpenGIS SQL: (1) boolean methods for topological relationships among spatial objects, and (2) methods for specifying spatial operations. We prove that the complete set of 2-dimensional spatial relationships defined by Egenhofer can all be specified using OpenGIS SQL operations and relationships. Our proof shows how each spatial relationship can be specified using OpenGIS SQL and thus provides users with the means of determining how each spatial relationship can be written in SQL. This provides users with enhanced usability and flexibility by providing the specific OpenGIS conditions for every possible 2-dimensional spatial relationship.

Proving completeness of OpenGIS SQL spatial relationships and operations

In this paper, we propose a new indexing structure, called the TI/R-tree, which combines techniques used in temporal access structures with techniques used in spatial access structures to provide a suitable means for maintaining and retrieving the history of geographic data.The TI/R-tree uses features from both the time index [ElWK90, Kour94] and the R-tree [Gutt84]. It has a tree structure similar to the time index and maintains a set of linearly ordered indexing points on the time dimension. The leaf nodes of the TI/R-tree refer to logical buckets which are organized as incremental R-trees; that is, at certain time points only deltas are kept. This permits the reconstruction of R-trees at any time point by using a number of logical buckets.

Ramez Elmasri

Papers

Reducing Energy Consumption through the Union of Disjoint Set Forests Algorithm in Sensor Networks

ADTP: a new protocol for data processing over the internet

Enhanced bioinformatics data modeling concepts and their use in querying and integration

Proving completeness of OpenGIS SQL spatial relationships and operations

The TI/R--Tree: a temporal--spatial access structure