Catálogo de publicaciones - libros

Many shape recognition techniques have been presented in literature, most of them from a quantitative perspective. Research has shown that qualitative reasoning better reflects the way humans deal with spatial reality. The current qualitative techniques are based on break points resulting in difficulties in comparing analogous relative positions along polylines. The presented shape representation technique is a qualitative approach based on division points, resulting in shape matrices forming a shape data model and thus forming the basis for a cognitively relevant similarity measure for shape representation and shape comparison, both locally and globally.

Indexing techniques have been developed for wireless data broadcast environments, in order to conserve the scarce power resources of the mobile clients. However, the use of interleaved index segments in a broadcast cycle increases the average access latency for the clients. In this paper, we present the broadcast-based spatial query processing algorithm for LBS. In this algorithm, we simply sort the data objects based on their locations, then the server broadcasts them sequentially to the mobile clients. The experimental results show that the proposed BBS scheme significantly reduces the .

Because moving objects usually moves on spatial networks, efficient trajectory index structures are required to gain good retrieval performance on their trajectories. However, there has been little research on trajectory index structure for spatial networks, like road networks. In this paper, we propose an efficient trajectory index structure for moving objects in Location-based Services (LBS). For this, we design our access scheme for efficiently dealing with the trajectories of moving objects on road networks. In addition, we provide both an insertion algorithm to store the initial information of moving object trajectories and one to store their segment information. We also provide a retrieval algorithm to find a set of moving objects whose trajectories match the segments of a query trajectory. Finally, we show that our trajectory access scheme achieves about one order of magnitude better retrieval performance than TB-tree.

For more than ten years MECOSIG has been used as a method for GIS design and implementation in various national and international projects achieved in our laboratory. During a decade, the method has been progressively improved and extended without modification of its basic principles. However the emergence of distributed GIS, implying several organizations capable to play various roles, requires the reappraisal of the methodology. New concerns are identified and a collection of new tools must be deployed. Taking the most of various recent researches completed for public authorities in Belgium, this paper presents some significant adaptations of the original MECOSIG method in order to cope with a distributed GIS environment.

Geoportals (geographic portals) are entry points on the Web, where various geographic information resources can be easily discovered. They organize geospatial data and services through catalogs containing metadata records, which can be queried in order to give access to related resources. However, the current organization of geographic information in metadata catalogs is unable to capture the semantics of the data being described; therefore users often miss geographical resources of interest when searching for geospatial data in the World Wide Web. In this paper, we present an innovative approach in the development of geoportals, based on the next generation of the Web, called the Semantic Web. This approach relies in the organization of the geo-data at the semantic level through appropriate geographic ontologies, and the exploitation of this organization through the user interface of the geoportal. To the best of our knowledge, this approach is the first that combines the expressiveness of geo-ontologies in the context of geographic portals.

Traditional trip planning involves decisions made by tourists in order to explore an environment, such as a geographic area, usually without having any prior knowledge or experience with it. Contemporary technological development has facilitated not only human mobility but also has set the path for various applications to assist tourists in way-finding, event notification using location-based services etc. Our approach explores how the use of ontologies can assist tourists plan their trip, in a web-based environment. The methodology consists of building two separate ontologies, one for the users profile and another one concerning tourism information and data in order to assist visitors of an area plan their visit.

We are happy and proud to introduce the proceedings for this 2nd ”Workshop on Ontologies, Semantics and E-learning”. We use the term ”ontologies” to refer to an as precise and formal as possible definition of the semantics of objects and their inter-relationships for a specific application domain.

It is interesting to note that the concept of ontologies has started to be applied in the context of learning technologies. Indeed, after some initial ontology related work in the late ’80s and early ’90s, mainly in the context of so-called ”Intelligent Tutoring Systems”, the focus over the last 10 years has been more on the development of learning objects, repositories and interoperability specifications, instead of on the formal representation and analysis of their meaning.

Traditionally performance support and e-Learning have been considered as two separate research fields. This paper integrates them by introducing the concept of context-aware product support systems, which utilizes the notions of context, information object and ontology. The context signifies whether learning or performing goals are pursued in different situations and defines the configuration of the domain knowledge accordingly. An information object is viewed as an enabler of a modular virtual documentation, advancing information reuse. The ontology formalizes the representation of the knowledge contained in the system, facilitates interoperability, and constitutes one of the main building blocks of context-aware product support systems. The prototype system developed illustrates the applicability of the approach.

Learning Object Metadata (LOM) is an interoperable standard aimed to foster the reuse of learning material for authoring lessons. Nevertheless, few work was done on taking advantage of LOM-semantics to facilitate retrieval of learning material. This article suggests an original approach which uses the structure of a lesson in order to automatically generate LOM-semantic-based queries for retrieving learning material for that lesson whereas the user continues to formulate easy-to-write queries without semantic specifications. This proposal consists of a four-component framework attempting to consider the main issues of semantic-based retrieval of documents.

This paper presents an ontology-based framework for repurposing learning object components. Unlike the usual practice where learning object components are assembled manually, the proposed framework enables on-the-fly access and repurposing of learning object components. The framework supports two processes: the decomposition of learning objects into their components as well as the automatic assembly of these components in real-world applications. For now, the framework supports slide presentations. As an application, we will present in this paper the integration of this functionality in MS PowerPoint.