Re-Pair Compression of Inverted Lists

Compression of inverted lists with methods that support fast intersection operations is an active research topic. Most compression schemes rely on encoding differences between consecutive positions with techniques that favor small numbers. In this paper we explore a completely different alternative: We use Re-Pair compression of those differences. While Re-Pair by itself offers fast decompression at arbitrary positions in main and secondary memory, we introduce variants that in addition speed up the operations required for inverted list intersection. We compare the resulting data structures with several recent proposals under various list intersection algorithms, to conclude that our Re-Pair variants offer an interesting time/space tradeoff for this problem, yet further improvements are required for it to improve upon the state of the art

Universal Indexes for Highly Repetitive Document Collections

Indexing highly repetitive collections has become a relevant problem with the emergence of large repositories of versioned documents, among other applications. These collections may reach huge sizes, but are formed mostly of documents that are near-copies of others. Traditional techniques for indexing these collections fail to properly exploit their regularities in order to reduce space. We introduce new techniques for compressing inverted indexes that exploit this near-copy regularity. They are based on run-length, Lempel-Ziv, or grammar compression of the differential inverted lists, instead of the usual practice of gap-encoding them. We show that, in this highly repetitive setting, our compression methods significantly reduce the space obtained with classical techniques, at the price of moderate slowdowns. Moreover, our best methods are universal, that is, they do not need to know the versioning structure of the collection, nor that a clear versioning structure even exists. We also introduce compressed self-indexes in the comparison. These are designed for general strings (not only natural language texts) and represent the text collection plus the index structure (not an inverted index) in integrated form. We show that these techniques can compress much further, using a small fraction of the space required by our new inverted indexes. Yet, they are orders of magnitude slower.Comment: This research has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk{\l}odowska-Curie Actions H2020-MSCA-RISE-2015 BIRDS GA No. 69094

Ancient Cartographies as a Basis for Geolocation Models in Public Space: The Case of Giambattista Nolli and its Heritage Application

In 1748, the architect and surveyor Giambattista Nolli mapped an abstract reality of the city of Rome. As a challenge to the inherited projections, it represented the city mixing streets, halls, corridors, churches, baths and markets as part of a unique public space network. A new way to design public space and rethink the whole urban system was opened by the possibility of containing in these representations a single layer with all kinds of public space (including the interior of public buildings). Despite this, Nolli's plan remained as a useless instrument since the hegemony of automobile mobility appeared as a pre-eminent system. This research tries to understand how the application of the ancient cartographies' methodology can improve the pedestrian mobility of historic cities by means of enhancing the graphic value of the system of Giambattista Nolli. Nowadays, free public space is represented as empty and built ones, as solid. This proposal would revert this reified conception of the city, understanding this baroque representation as an instrument of identification and assessment of the transitional heritage. The clues unveiled by Nolli seem to be able to integrate the plans of public buildings within the urban tissue, which would result in a step towards the full integration of cartography and mobility. The success of the comprehensive tools offered by large servers such as Alphabet inc. (Google) or Bing Maps confirm the suitability of the combination of new technologies and Big Data with urban planning, reaching the synchronisation of Smart Cities. Nowadays, open public space can be 'walked in' from any electronic device, consequently, the application of the "Nolli methodology" would implement the model of urban geolocation with the assimilation of inner public spaces. In the creation of a great global map of the public space, a chimaera could be intuited. This would be discussed within a tangible reality: every open public space is already housed in the Big Data and it is accessible through geolocation tools. The inclusion of the of the public buildings' interiors would contribute to develop a greater permeability between city and citizens. Furthermore, this representation would optimize pedestrian travel times and would be able to expand the geolocation system network as a documentary repository

Evolución histórica de la morfología urbana en los altiplanos nororientales de la provincia de Granada

Para conocer la esencia y la identidad de los diferentes asentamientos urbanos, los patrones morfológicos son tan importantes como los económicos, sociales, políticos y culturales. Por ese motivo, a continuación se va a analizar la evolución histórica de los asentamientos de las comarcas de Baza y Huéscar, desde sus orígenes, sus sucesivas transformaciones, e identificando y diseccionando sus variados componentes. El particular devenir histórico, los condicionantes del medio natural, y las determinadas formas de vida, en esta zona, han quedado plasmadas en la morfología urbana de sus pueblos y ciudades. Es decir, el solapamiento en asentamientos de diversas culturas y usos etnográficos ha generado diversas morfologías y paisajes construidos, de gran valor identitario, ambiental e histórico. Pero la globalización ignora la cultura local, el paisaje urbano, transformando en confuso a este último, por lo que es preciso una valoración social y un planeamiento urbano adecuado para su preservación en el tiempo.To know the essence and the identity of the different urban settlements, morphological patterns are so important as the financial ones, social, politicians and cultural. For that reason, we have to analyze the historical evolution of the regions’ settlements of Baza and Huéscar, from its origin, successive transformations, and identifying and dissecting its varied ingredients. The particular history, natural factors, and determined forms of life, in this zone, have been reflected in the urban morphology of his villages and cities. That is, the overlap in settlements of several cultures and ethnographical uses has generated several morphologies and built landscapes, of great value environmental and historic. But the globalization ignores the local culture, the cityscape, transforming in confusing to this last one, which is why is precise a social assessment and a urban planification suitable for its preservation

The problem of estimating the volatility of zero coupon bond interest rate

Financial literature and financial industry use often zero coupon yield curves as input for testing hypotheses, pricing assets or managing risk. They assume this provided data as accurate. We analyse implications of the methodology and of the sample selection criteria used to estimate the zero coupon bond yield term structure on the resulting volatility of spot rates with different maturities. We obtain the volatility term structure using historical volatilities and Egarch volatilities. As input for these volatilities we consider our own spot rates estimation from GovPX bond data and three popular interest rates data sets: from the Federal Reserve Board, from the US Department of the Treasury (H15), and from Bloomberg. We find strong evidence that the resulting zero coupon bond yield volatility estimates as well as the correlation coefficients among spot and forward rates depend significantly on the data set. We observe relevant differences in economic terms when volatilities are used to price derivatives

Pipeline template for streaming applications on heterogeneous chips

We address the problem of providing support for executing single streaming applications implemented as a pipeline of stages that run on heterogeneous chips comprised of several cores and one on-chip GPU. In this paper, we mainly focus on the API that allows the user to specify the type of parallelism exploited by each pipeline stage running on the multicore CPU, the mapping of the pipeline stages to the devices (GPU or CPU), and the number of active threads. We use a real streaming application as a case of study to illustrate the experimental results that can be obtained with this API. With this example, we evaluate how the different parameter values affect the performance and energy efficiency of a heterogenous on-chip processor (Exynos 5 Octa) that has three different computational cores: a GPU, an ARM Cortex-A15 quad-core, and an ARM Cortex-A7 quad-core.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto de Excelencia de la Junta de Andalucía P11-TIC-08144

Protected Natural Spaces, Agrarian Specialization and the Survival of Rural Territories: The Cases of Sierra Nevada (Spain) and Alta Murgia (Italy)

In Europe today, there is increasing interest in the management of protected spaces, not only in an attempt to ensure their conservation but also because of their enormous potential for promoting rural development. These protected spaces are generally designed from the top down, although, in an increasing number of cases, they are being promoted by rural communities themselves. The situation across Europe with regard to protected areas is extraordinarily complex due, among other reasons, to the variety of categories and types of protected areas at the regional level. The objective of this study was to compare two parks: the Sierra Nevada National and Natural Park in Andalusia, Spain, and the Alta Murgia National Park in Apulia, Italy, in order to identify any similarities and/or differences between them. To this end, we performed a dynamic analysis of the evolution of the crops, uses, and livestock species using a specific indicator that can detect local dynamics by comparing areas inside the parks with those in the immediate surrounding areas. The results pointed, in part, to a resurgence of these places. In both cases, a trend was observed towards more extensive farming of certain crops and livestock species that are more profitable and/or more highly regarded as quality products. In other cases, there was a risk of traditional crops and agricultural landscapes being abandoned and lost. Various threats were identified in relation to capital-intensive forms of agriculture, especially involving greenhouse cultivation on the Mediterranean coast in the provinces of Granada and Almeria.Ministry of Economy, Industry, and Competitiveness, Research Project "Successes and failures in the practice of neo-endogenous rural development in the European Union (1991-2013), RURALWIN" CSO2017-89657-

OpenZmeter: An Efficient Low-Cost Energy Smart Meter and Power Quality Analyzer

Power quality and energy consumption measurements support providers and energy users with solutions for acquiring and reporting information about the energy supply for residential, commercial, and industrial sectors. In particular, since the average number of electronic devices in homes increases year by year and their sensitivity is very high, it is not only important to monitor the total energy consumption, but also the quality of the power supplied. However, in practice, end-users do not have information about the energy consumption in real-time nor about the quality of the power they receive, because electric energy meters are too expensive and complex to be handled. In order to overcome these inconveniences, an innovative, open source, low-cost, precise, and reliable power and electric energy meter is presented that can be easily installed and managed by any inexperienced user at their own home in urban or rural areas. The system was validated in a real house over a period of two weeks, showing interesting results and findings which validate our proposal

Identificación de recursos turísticos potenciales importantes por criterios de singularidad identitaria y universal. El municipio de Ugíjar en la Comarca de las Alpujarras

The promotion of rural areas is a key issue to fight against their depopulation. Currently there are deficiencies in the perception of the value of own resources in many of these territories. Situation due to factors such as lack of territorial culture, local deepening and research dissemination of those which may have certain singularities or aspects of interest at different scales. The safeguarding of territorial identity makes possible an evasion before the banalizing processes while conserving the patrimonial wealth.La promoción de las áreas rurales es una cuestión primordial para luchar contra su despoblamiento. Actualmente existen deficiencias en la percepción del valor de los recursos propios existentes en muchos de estos territorios. Situación debida a factores como la falta de cultura territorial, profundización local y difusión investigadora de aquellos que pudieran poseer ciertas singularidades o aspectos de interés a diferentes escalas. La salvaguardia de la identidad territorial posibilita una evasión ante los procesos banalizadores conservando a su vez la riqueza patrimonial

The Relationship Between Social Capital and Geographical Indications. A Comparative Case Study of Prosciutto Veneto Berico Euganeo PDO (Italy) and Jamón de Trevélez PGI (Spain)

This study compares two EU quality-label schemes in Italy and Spain: Prosciutto Veneto Berico Euganeo PDO and Jamón de Trevélez PGI, respectively. It aims to demonstrate that social capital plays an important role in both establishing and managing geographical indications (GIs), and that obtaining this label reinforces existing networks, so boosting rural development. The research is based on semi-structured interviews with 7 key informants, the analysis of institutional information and legislation, and of statistical data on the socioeconomic structure of both geographical areas. The research reveals two quite different experiences in obtaining EU quality labels, regardless of the fact that the products, places and people involved in this process have various aspects in common. This study illustrates how the advantages resulting from these high-quality labels and their impact on rural development can vary in relation to the level of social capital and the strength of local networks