Purpose: This study aims to present the digital library Galician virtual library (BVG, for “Biblioteca Virtual Galega”) in Galician.Design/methodology/approach: The paper shows the objectives pursued by the BVG, its development, putting special emphasis on the main technological challenges, and presents some data about its usage.Findings: A digital library can be used to stimulate a lesser‐used language and to promote the culture and tourism of a region.Originality/value: The paper shows how a digital library can be used to strengthen the Galician language, which is currently categorised as a “Lesser Used Language” in the European Community and to contribute to the preservation and spreading of Galician culture and literary works, either from current authors or from previous documents. It also provides a digital publishing house for new authors and opens a communication channel between current authors and their readers. Finally, it helps to connect a scattered community like the Galician, offering a centralised access point to any information about Galicia. This work also presents some technological innovations included in the BVG, especially from the viewpoint of user interface design and search by content.

Binary relations are commonly used in Computer Science for modeling data. In addition to classical representations using matrices or lists, some compressed data structures have recently been proposed to represent binary relations in compact space, such as the k2-tree and the Binary RelationWavelet Tree (BRWT). Knowing their storage needs, supported operations and time performance is key for enabling an appropriate choice of data representation given a domain or application, its data distribution and typical operations that are computed over the data. In this work, we present an empirical comparison among several compressed representations for binary relations. We analyze their space usage and the speed of their operations using different (synthetic and real) data distributions. We include both neighborhood and set operations, also proposing algorithms for set operations for the BRWT, which were not presented before in the literature. We conclude that there is not a clear choice that outperforms the rest, but we give some recommendations of usage of each compact representation depending on the data distribution and types of operations performed over the data. We also include a scalability study of the data representations.

In this article, we present a system that combines indoor positioning with a compression algorithm for trajectories in the context of a nursing home. Our aim is to gather and effectively represent the location of the residents and caregivers along time, while allowing for efficient access to those data. We briefly show the system architecture that enables the automatic tracking of user’s movements and consequently the gathering of their locations. Then, we present indRep, our compact representation to handle positioning data using grammar-based compression, and provide two basic operations that enable pseudorandom access to the data. Finally, we include experiments that show that indRep is competitive with well-known general-purpose compressors in terms of compression effectiveness and also provides fast access to the compressed data. We expect both features would enable exploitation functionalities even in computers with rather low computational resources.