ChImp:Visualizing Ontology Changes and their Impact in Protégé

Today, ontologies are an established part of many applications and research. However, ontologies evolve over time, and ontology editors---engineers and domain experts---need to be aware of the consequences of changes while editing. Ontology editors might not be fully aware of how they are influencing consistency, quality, or the structure of the ontology, possibly causing applications to fail. To support editors and increase their sensitivity towards the consequences of their actions, we conducted a user survey to elicit preferences for representing changes, e.g., with ontology metrics such as number of classes and properties. Based on the survey, we developed ChImp---a Protégé plug-in to display information about the impact of changes in real-time. During editing of the ontology, ChImp lists the applied changes, checks and displays the consistency status, and reports measures describing the effect on the structure of the ontology. Akin to software IDEs and integrated testing approaches, we hope that displaying such metrics will help to improve ontology evolution processes in the long run

Towards a Top-K SPARQL Query Benchmark Generator

The research on optimization of top-k SPARQL query would largely benefit from the establishment of a benchmark that allows comparing different approaches. For such a benchmark to be meaningful, at least two requirements should hold: 1) the benchmark should resemble reality as much as possible, and 2) it should stress the features of the topk SPARQL queries both from a syntactic and performance perspective. In this paper we propose Top-k DBPSB: an extension of the DBpedia SPARQL benchmark (DBPSB), a benchmark known to resemble reality, with the capabilities required to compare SPARQL engines on top-k queries.Web Information System

Towards A Question Answering System over Temporal Knowledge Graph Embedding

Question Answering (QA) over knowledge graphs is a vital topic within information retrieval. Questions with temporal intent are a special case of questions for QA systems that have received only limited attention so far. In this paper, we study using temporal knowledge graph embeddings (TKGEs) for temporal QA. Firstly, we propose a microservice-based architecture for building temporal QA systems on pre-trained TKGE models. Secondly, we present a Bayesian model average (BMA) ensemble method, where results of several link prediction tasks on separated TKGE models are combined to find better answers. Within the system built using the microservice-based architecture, the experiments on two benchmark datasets show that BMA provides better results than the individual models.</p

Visualising the effects of ontology changes and studying their understanding with ChImp

Due to the Semantic Web's decentralised nature, ontology engineers rarely know all applications that leverage their ontology. Consequently, they are unaware of the full extent of possible consequences that changes might cause to the ontology. Our goal is to lessen the gap between ontology engineers and users by investigating ontology engineers’ understanding of ontology changes’ impact at editing time. Hence, this paper introduces the Protégé plugin ChImp which we use to reach our goal. We elicited requirements for ChImp through a questionnaire with ontology engineers. We then developed ChImp according to these requirements and it displays all changes of a given session and provides selected information on said changes and their effects. For each change, it computes a number of metrics on both the ontology and its materialisation. It displays those metrics on both the originally loaded ontology at the beginning of the editing session and the current state to help ontology engineers understand the impact of their changes. We investigated the informativeness of materialisation impact measures, the meaning of severe impact, and also the usefulness of ChImp in an online user study with 36 ontology engineers. We asked the participants to solve two ontology engineering tasks – with and without ChImp (assigned in random order) – and answer in-depth questions about the applied changes as well as the materialisation impact measures. We found that ChImp increased the participants’ understanding of change effects and that they felt better informed. Answers also suggest that the proposed measures were useful and informative. We also learned that the participants consider different outcomes of changes severe, but most would define severity based on the amount of changes to the materialisation compared to its size. The participants also acknowledged the importance of quantifying the impact of changes and that the study will affect their approach of editing ontologies

Imágenes sociales sobre las instituciones de acogida

Este estudo investigou as imagens sociais atribuídas às instituições de acolhimento através de um questionário aberto. Participaram 202 pessoas, com idades entre 16 e 69 anos (M=32,76, DP=11,67), que indicaram 914 palavras para descrever as instituições. A partir de uma análise de conteúdo, foram identificadas categorias: (1) Acolhimento/Proteção (n=342), (2) Organização/Funcionamento (n=238), (3) Recursos (n=229), (4) Formação/Preparação (n=73), (5) Permanência/Provisoriedade (n=18), (6) Outros (n=14), sendo que em cada uma as palavras ainda foram classificadas em valência positiva ou negativa. Houve predominância da valência positiva em todas as categorias, sugerindo uma imagem social positiva sobre as instituições. Os dados indicam que as funções de acolhimento e organização, bem como a disponibilidade de recursos das instituições são mais reconhecidas pelos participantes.This study investigated the social images assigned to residential care institutions, through an open questionnaire. The participants were 202 people, aged 16 to 69 years old (M=32.76, SD=11.67), who indicated 914 words to describe the institutions. Through content analysis, the following categories were identified: (1) Care/Protection (n=342), (2) Organization/Operation (n=238), (3) Resources (n=229), (4) Formation/Preparation (n=73), (5) Permanence/Temporariness (n=18), (6) Others (n=14), and each word was classified by its positive or negative valence. There was a predominance of positive valence in all categories, suggesting a positive social image of these institutions. The data indicated that the functions of care and organization, as well as the availability of resources of the institutions are more recognized by the participants.Este estudio investigó las percepciones sociales sobre las instituciones de acogimiento infantil a través de un cuestionario abierto. Participaron 202 personas, con edades entre 16 y 69 años (M = 32.76, DE = 11.67), las cuales usaron 914 palabras para describir las instituciones. Un análisis de contenido generó categorías: (1) Acogimiento/Protección (n=342), (2) Organización/Operación (n=238), (3) Recursos (n=229), (4) Formación/Preparación (n=73), (5) Permanencia/Temporalidad (n=18), (6) Otros (n=14), y cada palabra aún fue clasificada con valencia positiva o negativa. Hubo un predominio de valencia positiva en todas las categorías, lo que sugiere una imagen social positiva de las instituciones. Los datos indican que las funciones de acogimiento y organización, así como la disponibilidad de recursos son más reconocidas por los participantes

Where are the RDF Streams?: Deploying RDF Streams on the Web of Data with TripleWave

RDF Stream Processing (RSP) bridges the gap between semantic technologies and data stream systems. Although a number of RSP systems have been recently proposed, no RDF streams are actually made publicly available on the Web. To cope with this, RSP engines require ad-hoc wrappers in order to be fed from non-RDF streams available on the Internet. In this paper we present TripleWave: an approach for publishing existing streams on the Web as RDF streams, using mappings to perform live transformation of data, and following the Linked Data principles. We implemented and deployed TripleWave for a concrete use-case: a live feed of updates of Wikipedia