X-som: A flexible ontology mapper

System interoperability is a well known issue, especially for heterogeneous information systems, where ontologybased representations may support automatic and usertransparent integration. In this paper we present X-SOM: an ontology mapping and integration tool. The contribution of our tool is a modular and extensible architecture that automatically combines several matching techniques by means of a neural network, performing also ontology debugging to avoid inconsistencies. Besides describing the tool components, we discuss the prototype implementation, which has been tested against the OAEI 2006 benchmark with promising results.

ODE-SWS: A Semantic Web Service Development Environment

Web Services (WS) are software modules that perform operations that are network-accessible through XML messaging. Web Services in the Semantic Web, that is, Semantic Web Services (SWS), should describe semantically their structure and capabilities to enable its automatic discovery, invocation and composition. In this work we present a development environment to design SWS in a language-independent manner. This environment is based on a framework that defines an ontology set to characterize how a SWS should be specified. The core ontology of this framework describes the SWS problem-solving behaviour and enables the SWS design at a conceptual level. Considering this framework, the SWS development environment is composed of (1) a graphical interface, in which the conceptual design of SWSs is performed, and (2) a tool set, which instantiates the framework ontologies according to the graphical model created by the user, verifies the completeness and consistency of the SWS through instance evaluation, and translates the SWS conceptual model description into SWS (and WS) languages, such as DAML-S, WSDL or UDDI. This tool set is integrated in the WebODE ontology engineering workbench in order to take advantage of its reasoning and ontology translation capabilities

RROVT: A Proposed Visualization Tool for Semantic Web Technologies

Visualization is the graphical or semi-graphical representation of information that aids human comprehension of and reasoning about that information. Visualization tools are critically important for creating, querying, visualizing and validating Semantic Web Data. Semantic Web, an efficient infrastructure that enhances visibility of knowledge on the web, is often used more specifically to refer to the formats and technologies that enable it. These technologies include RDF, RDFS and OWL. However, lack of robust and efficient tools to visualize, analyze and represent these technologies within time and space constraint remains a big challenge. In this study, semantic web technologies and their visualization tools were reviewed. RROVT (RDF, RDFS, OWL Visualization Tool), a tool to evaluate and represent formal description of concepts, terms and relationships of data models within a given knowledge domain as well as manage time and space complexities for publishing contents of the semantic web more efficiently is developed and proposed. Performance of RROVT was investigated on samples of semantic web documents implementing RDF, RDFS and OWL technologies. The proposed tool showed remarkable improvement over the existing tools as it aids a better comprehension of the syntax and semantics of semantic web technologies investigated in this study. Keywords: Semantic Web, Visualization Tool, Semantic Web Technologie

A Goal and Ontology Based Approach for Generating ETL Process Specifications

Data warehouse (DW) systems development involves several tasks such as defining requirements, designing DW schemas, and specifying data transformation operations. Indeed, the success of DW systems is very much dependent on the proper design of the extracting, transforming, and loading (ETL) processes. However, the common design-related problems in the ETL processes such as defining user requirements and data transformation specifications are far from being resolved. These problems are due to data heterogeneity in data sources, ambiguity of user requirements, and the complexity of data transformation activities. Current approaches have limitations on the reconciliation of DW requirement semantics towards designing the ETL processes. As a result, this has prolonged the process of the ETL processes specifications generation. The semantic framework of DW systems established from this study is used to develop the requirement analysis method for designing the ETL processes (RAMEPs) from the different perspectives of organization, decision-maker, and developer by using goal and ontology approaches. The correctness of RAMEPs approach was validated by using modified and newly developed compliant tools. The RAMEPs was evaluated in three real case studies, i.e., Student Affairs System, Gas Utility System, and Graduate Entrepreneur System. These case studies were used to illustrate how the RAMEPs approach can be implemented for designing and generating the ETL processes specifications. Moreover, the RAMEPs approach was reviewed by the DW experts for assessing the strengths and weaknesses of this method, and the new approach is accepted. The RAMEPs method proves that the ETL processes specifications can be derived from the early phases of DW systems development by using the goal-ontology approach

Evolving NoSQL Databases Without Downtime

NoSQL databases like Redis, Cassandra, and MongoDB are increasingly popular because they are flexible, lightweight, and easy to work with. Applications that use these databases will evolve over time, sometimes necessitating (or preferring) a change to the format or organization of the data. The problem we address in this paper is: How can we support the evolution of high-availability applications and their NoSQL data online, without excessive delays or interruptions, even in the presence of backward-incompatible data format changes? We present KVolve, an extension to the popular Redis NoSQL database, as a solution to this problem. KVolve permits a developer to submit an upgrade specification that defines how to transform existing data to the newest version. This transformation is applied lazily as applications interact with the database, thus avoiding long pause times. We demonstrate that KVolve is expressive enough to support substantial practical updates, including format changes to RedisFS, a Redis-backed file system, while imposing essentially no overhead in general use and minimal pause times during updates.Comment: Update to writing/structur

A semantic web framework to integrate cancer omics data with biological knowledge

BACKGROUND: The RDF triple provides a simple linguistic means of describing limitless types of information. Triples can be flexibly combined into a unified data source we call a semantic model. Semantic models open new possibilities for the integration of variegated biological data. We use Semantic Web technology to explicate high throughput clinical data in the context of fundamental biological knowledge. We have extended Corvus, a data warehouse which provides a uniform interface to various forms of Omics data, by providing a SPARQL endpoint. With the querying and reasoning tools made possible by the Semantic Web, we were able to explore quantitative semantic models retrieved from Corvus in the light of systematic biological knowledge. RESULTS: For this paper, we merged semantic models containing genomic, transcriptomic and epigenomic data from melanoma samples with two semantic models of functional data - one containing Gene Ontology (GO) data, the other, regulatory networks constructed from transcription factor binding information. These two semantic models were created in an ad hoc manner but support a common interface for integration with the quantitative semantic models. Such combined semantic models allow us to pose significant translational medicine questions. Here, we study the interplay between a cell's molecular state and its response to anti-cancer therapy by exploring the resistance of cancer cells to Decitabine, a demethylating agent. CONCLUSIONS: We were able to generate a testable hypothesis to explain how Decitabine fights cancer - namely, that it targets apoptosis-related gene promoters predominantly in Decitabine-sensitive cell lines, thus conveying its cytotoxic effect by activating the apoptosis pathway. Our research provides a framework whereby similar hypotheses can be developed easily

Africa-EU Renewable Energy Research and Innovation Symposium 2018 (RERIS 2018)

This open access book presents the proceedings of the 2nd Africa-EU Renewable Energy Research and Innovation Symposium (RERIS 18), held in Maseru, Lesotho in January 2018. The symposium aimed to foster research cooperation on renewable energy between Africa and Europe – in academia, as well as the private and public sectors. Addressing thematic areas such as • Grid-connected renewable energy; • Decentralised renewable and household energy solutions; • Energy socioeconomics; and • Promotion of energy research, innovation, education and entrepreneurship, the book brings together contributions from academics and practitioners from the EU and Africa to enable mutual learning and knowledge transfer – a key factor in boosting sustainable development in the African renewable energy market. It also plays a significant role in promoting African renewable energy research, which helps to secure energy supply in both rural and urban areas and to increase generation capacities and energy system resilience. This book is an invaluable resource for academics and professionals across the renewable energy spectrum

Distributed Join Approaches for W3C-Conform SPARQL Endpoints

Currently many SPARQL endpoints are freely available and accessible without any costs to users: Everyone can submit SPARQL queries to SPARQL endpoints via a standardized protocol, where the queries are processed on the datasets of the SPARQL endpoints and the query results are sent back to the user in a standardized format. As these distributed execution environments for semantic big data (as intersection of semantic data and big data) are freely accessible, the Semantic Web is an ideal playground for big data research. However, when utilizing these distributed execution environments, questions about the performance arise. Especially when several datasets (locally and those residing in SPARQL endpoints) need to be combined, distributed joins need to be computed. In this work we give an overview of the various possibilities of distributed join processing in SPARQL endpoints, which follow the SPARQL specification and hence are "W3C conform". We also introduce new distributed join approaches as variants of the Bitvector-Join and combination of the Semi- and Bitvector-Join. Finally we compare all the existing and newly proposed distributed join approaches for W3C conform SPARQL endpoints in an extensive experimental evaluation

RDF Querying

Reactive Web systems, Web services, and Web-based publish/ subscribe systems communicate events as XML messages, and in many cases require composite event detection: it is not sufficient to react to single event messages, but events have to be considered in relation to other events that are received over time. Emphasizing language design and formal semantics, we describe the rule-based query language XChangeEQ for detecting composite events. XChangeEQ is designed to completely cover and integrate the four complementary querying dimensions: event data, event composition, temporal relationships, and event accumulation. Semantics are provided as model and fixpoint theories; while this is an established approach for rule languages, it has not been applied for event queries before