Informatics Research Institute (IRIS) September 2008 newsletter

2007-8 was a very busy year for IRIS. It was a bumper year for visiting Profs with Prof Michael Myers visiting from New Zealand, Prof Brian Fitzgerald visiting from University of Limerick, Ireland, Prof. Uzay Kaymak visiting from Erasmus University Netherlands and Prof Steve Sawyer visiting from Pennsylvania State University, USA. Their visits enriched our doctoral school, seminar programme workshops and our research. We were very lucky to have such a distinguished line up of visiting professors and we offer them hearty thanks and hope to keep ongoing research links with them

An Efficient Representation of Enriched Temporal Trajectories

[Abstract] We present a novel representation of enriched trajectories of a mobile workforce management system. In this system, employees are tracked during their working day and both their routes and the tasks performed at each time instant are recorded. Our proposal tackles the representation of this information paying special attention to the space footprint without neglecting query time. We performed experiments using real and synthetic datasets where we show the compression effectiveness as well as the efficiency at query time. Our results showed that our proposal yields promising results in terms of the space needed to represent both users’ locations and activities while performing access queries to the original data within microseconds.Xunta de Galicia; ED431G 2019/01Xunta de Galicia; IG240.2020.1.185Xunta de Galicia; IN852A 2018/14Partially funded by the CITIC research center funded by Xunta/FEDER-UE 2014-2020 Program, grant ED431G 2019/01. MICIU (PGE/ERDF) [Datos 4.0: TIN2016-78011-C4-1-R; STEPS: RTC-2017-5908-7; BIZDEVOPS: RTI2018-098309-B-C32]. IGAPE/Xunta (FEDER-UE) 2014-2020 [IG240.2020.1.185]. Xunta/GAIN (ERDF) [GEMA: IN852A 2018/14] and by FPI Program [BES-2017-081390].https://www.scitepress.org/ProceedingsDetails.aspx?ID=H6opWeZtwKs=&t=

Benefits of Location-Based Access Control:A Literature Study

Location-based access control (LBAC) has been suggested as a means to improve IT security. By 'grounding' users and systems to a particular location, \ud attackers supposedly have more difficulty in compromising a system. However, the motivation behind LBAC and its potential benefits have not been investigated thoroughly. To this end, we perform a structured literature review, and examine the goals that LBAC can potentially fulfill, \ud the specific LBAC systems that realize these goals and the context on which LBAC depends. Our paper has four main contributions:\ud first we propose a theoretical framework for LBAC evaluation, based on goals, systems and context. Second, we formulate and apply criteria for evaluating the usefulness of an LBAC system. Third, we identify four usage scenarios for LBAC: open areas and systems, hospitals, enterprises, and finally data centers and military facilities. Fourth, we propose directions for future research:\ud (i) assessing the tradeoffs between location-based, physical and logical access control, (ii) improving the transparency of LBAC decision making, and \ud (iii) formulating design criteria for facilities and working environments for optimal LBAC usage

Geospatial information infrastructures

Manual of Digital Earth / Editors: Huadong Guo, Michael F. Goodchild, Alessandro Annoni .- Springer, 2020 .- ISBN: 978-981-32-9915-3Geospatial information infrastructures (GIIs) provide the technological, semantic,organizationalandlegalstructurethatallowforthediscovery,sharing,and use of geospatial information (GI). In this chapter, we introduce the overall concept and surrounding notions such as geographic information systems (GIS) and spatial datainfrastructures(SDI).WeoutlinethehistoryofGIIsintermsoftheorganizational andtechnologicaldevelopmentsaswellasthecurrentstate-of-art,andreflectonsome of the central challenges and possible future trajectories. We focus on the tension betweenincreasedneedsforstandardizationandtheever-acceleratingtechnological changes. We conclude that GIIs evolved as a strong underpinning contribution to implementation of the Digital Earth vision. In the future, these infrastructures are challengedtobecomeflexibleandrobustenoughtoabsorbandembracetechnological transformationsandtheaccompanyingsocietalandorganizationalimplications.With this contribution, we present the reader a comprehensive overview of the field and a solid basis for reflections about future developments

Representation and Exploitation of Event Sequences

Programa Oficial de Doutoramento en Computación . 5009V01[Abstract] The Ten Commandments, the thirty best smartphones in the market and the five most wanted people by the FBI. Our life is ruled by sequences: thought sequences, number sequences, event sequences. . . a history book is nothing more than a compilation of events and our favorite film is just a sequence of scenes. All of them have something in common, it is possible to acquire relevant information from them. Frequently, by accumulating some data from the elements of each sequence we may access hidden information (e.g. the passengers transported by a bus on a journey is the sum of the passengers who got on in the sequence of stops made); other times, reordering the elements by any of their characteristics facilitates the access to the elements of interest (e.g. the publication of books in 2019 can be ordered chronologically, by author, by literary genre or even by a combination of characteristics); but it will always be sought to store them in the smallest space possible. Thus, this thesis proposes technological solutions for the storage and subsequent processing of events, focusing specifically on three fundamental aspects that can be found in any application that needs to manage them: compressed and dynamic storage, aggregation or accumulation of elements of the sequence and element sequence reordering by their different characteristics or dimensions. The first contribution of this work is a compact structure for the dynamic compression of event sequences. This structure allows any sequence to be compressed in a single pass, that is, it is capable of compressing in real time as elements arrive. This contribution is a milestone in the world of compression since, to date, this is the first proposal for a variable-to-variable dynamic compressor for general purpose. Regarding aggregation, a data warehouse-like proposal is presented capable of storing information on any characteristic of the events in a sequence in an aggregated, compact and accessible way. Following the philosophy of current data warehouses, we avoid repeating cumulative operations and speed up aggregate queries by preprocessing the information and keeping it in this separate structure. Finally, this thesis addresses the problem of indexing event sequences considering their different characteristics and possible reorderings. A new approach for simultaneously keeping the elements of a sequence ordered by different characteristics is presented through compact structures. Thus, it is possible to consult the information and perform operations on the elements of the sequence using any possible rearrangement in a simple and efficient way.[Resumen] Los diez mandamientos, los treinta mejores móviles del mercado y las cinco personas más buscadas por el FBI. Nuestra vida está gobernada por secuencias: secuencias de pensamientos, secuencias de números, secuencias de eventos. . . un libro de historia no es más que una sucesión de eventos y nuestra película favorita no es sino una secuencia de escenas. Todas ellas tienen algo en común, de todas podemos extraer información relevante. A veces, al acumular algún dato de los elementos de cada secuencia accedemos a información oculta (p. ej. los viajeros transportados por un autobús en un trayecto es la suma de los pasajeros que se subieron en la secuencia de paradas realizadas); otras veces, la reordenación de los elementos por alguna de sus características facilita el acceso a los elementos de interés (p. ej. la publicación de obras literarias en 2019 puede ordenarse cronológicamente, por autor, por género literario o incluso por una combinación de características); pero siempre se buscará almacenarlas en el espacio más reducido posible sin renunciar a su contenido. Por ello, esta tesis propone soluciones tecnológicas para el almacenamiento y posterior procesamiento de secuencias, centrándose concretamente en tres aspectos fundamentales que se pueden encontrar en cualquier aplicación que precise gestionarlas: el almacenamiento comprimido y dinámico, la agregación o acumulación de algún dato sobre los elementos de la secuencia y la reordenación de los elementos de la secuencia por sus diferentes características o dimensiones. La primera contribución de este trabajo es una estructura compacta para la compresión dinámica de secuencias. Esta estructura permite comprimir cualquier secuencia en una sola pasada, es decir, es capaz de comprimir en tiempo real a medida que llegan los elementos de la secuencia. Esta aportación es un hito en el mundo de la compresión ya que, hasta la fecha, es la primera propuesta de un compresor dinámico “variable to variable” de carácter general. En cuanto a la agregación, se presenta una propuesta de almacén de datos capaz de guardar la información acumulada sobre alguna característica de los eventos de la secuencia de modo compacto y fácilmente accesible. Siguiendo la filosofía de los actuales almacenes de datos, el objetivo es evitar repetir operaciones de acumulación y agilizar las consultas agregadas mediante el preprocesado de la información manteniéndola en esta estructura. Por último, esta tesis aborda el problema de la indexación de secuencias de eventos considerando sus diferentes características y posibles reordenaciones. Se presenta una nueva forma de mantener simultáneamente ordenados los elementos de una secuencia por diferentes características a través de estructuras compactas. Así se permite consultar la información y realizar operaciones sobre los elementos de la secuencia usando cualquier posible ordenación de una manera sencilla y eficiente

Semantic-Based Destination Suggestion in Intelligent Tourism Information Systems

Abstract. In recent years, there has been a growing interest in mining trajectories of moving objects. Advances in this data mining task are likely to support the development of new applications such as mobility prediction and service pre-fetching. Approaches reported in the literature consider only spatio-temporal information provided by collected trajectories. However, some applications demand additional sources of information to make correct predictions. In this work, we consider the case of an on-line tourist support service which aims at suggesting places to visit in the nearby. We assume tourist interests depend both on her/his geographical position and on the “semantic ” information extracted from geo-referenced documents associated to the visited sites. Therefore, the suggestion is based on both spatio-temporal data as well as on textual data. To deal with tourist’s interest drift we apply a time-slice density estimation method. Experimental results are reported for two scenarios.

The Future of the Internet III

Presents survey results on technology experts' predictions on the Internet's social, political, and economic impact as of 2020, including its effects on integrity and tolerance, intellectual property law, and the division between personal and work lives