Description and Optimization of Abstract Machines in a Dialect of Prolog

In order to achieve competitive performance, abstract machines for Prolog and related languages end up being large and intricate, and incorporate sophisticated optimizations, both at the design and at the implementation levels. At the same time, efficiency considerations make it necessary to use low-level languages in their implementation. This makes them laborious to code, optimize, and, especially, maintain and extend. Writing the abstract machine (and ancillary code) in a higher-level language can help tame this inherent complexity. We show how the semantics of most basic components of an efficient virtual machine for Prolog can be described using (a variant of) Prolog. These descriptions are then compiled to C and assembled to build a complete bytecode emulator. Thanks to the high level of the language used and its closeness to Prolog, the abstract machine description can be manipulated using standard Prolog compilation and optimization techniques with relative ease. We also show how, by applying program transformations selectively, we obtain abstract machine implementations whose performance can match and even exceed that of state-of-the-art, highly-tuned, hand-crafted emulators.Comment: 56 pages, 46 figures, 5 tables, To appear in Theory and Practice of Logic Programming (TPLP

Millimeter Wave Antenna Array Calibration and Validation for 5G New Radio Access

This Master thesis work was performed in Ericsson AB, Lund. It studies and validates two classes of algorithms to be used in mm-wave massive MIMO antenna arrays, for their use in the future 5G mobile communication systems. The first class of algorithms relates to the calibration of the transceiver (TRX) chains responses of the antenna array and makes use of the antenna array mutual coupling, which is considered as known by the system. It is used to compensate for inaccuracies in the TRX base-band complex responses, caused by environmental conditions such as temperature, humidity and aging, which are much more critical in mm-wave than conventional bands. After the calibration, the beamforming capabilities of the massive MIMO systems are increased. The second class of algorithms is related to the estimation of antenna array mutual coupling matrix, due to the fact that this information is used in the first method. The antenna array mutual coupling estimation algorithm was proposed by Ericsson's engineers and tested in this work. Since the systems considered will work at mm-wave frequencies, small construction errors can create big differences in antenna array coupling properties, so the coupling matrix must be estimated for each constructed system of the same kind. Several estimation and calibration algorithms were simulated, using Matlab® as a software for simulation, and analyzed. The estimation of TRX chains' complex responses is needed. Two estimation algorithms are used, referred as linear and non-linear least squares estimation. These estimation algorithms need to use the information regarding the antenna array mutual coupling matrix and over-the-air (OTA) self-measurements between pairs of elements in the antenna array. These measurements can be done considering all the possible pairs of elements in the antenna array (full measurements) or just a subset of the closest pairs (neighbour measurements). Firstly, simulations using a generic case were done, and later, simulations considering constraints in an Ericsson radio module proprietary system were done. Internal and external unwanted interference in the radio system were considered, to check for limitations in the estimation algorithms. So as to validate the proposed methods and algorithms, a testbed system using a radio module working at 28 GHz was built and measured. The signal levels and frequencies in the HW components of the testbed were calculated using the data-sheets of the components and later measured using a vector network analyzer and an spectrum analyzer. The last task was to write the code for controlling the radio module, then perform calibration using it and finally measure the performance of the algorithm using an an-echoic chamber. Due to a lack of time, the code needed to do the OTA measurements, the OTA measurements and the validation of the algorithms are left as future work. Observing the results of the simulations, several recommendations are made for future measurement validations. One common conclusion is that it is best to perform the minimum amount of self-measurements available, with those being the ones corresponding to the strongest coupling gains between elements in the antenna array. There were different preferred algorithms for calibration depending on the value of the signal-to-noise ratio (SNR) and the value of the signal-to-interference (SIR) ratio. Regarding the antenna array coupling matrix estimation, the conclusion is that the algorithm proposed by Ericsson's engineers works, but in order to achieve good results, the required post-processing SNR values of the related measurements may be too big. Therefore, it may take too long to perform these measurements. Possibilities to improve this algorithm are recommended and left as future work. Regarding the HW to be used in the testbed, it is recommended to add some extra components in order to improve the quality of the signals in the system, for future measurements.Do you remember a time when you were watching a standard definition (SD) YouTube video or streaming a song on your laptop or PC and the player suddenly stopped? Nowadays you want to watch streaming videos on your laptop or mobile phone in a high-definition (1080p) format and in the future you may even want to stream 4K 3D videos and watch them in your Smart-TV or mobile phone. Mobile services are expected to be fast, reliable and cheap. Apart from this, the number of connected devices is growing exponentially, and three times more devices are expected to be connected in the next 5 years. Consequently, scientists and engineers are working towards developing and installing increasingly sophisticated systems to meet today's and tomorrow's user demands. When it comes to cellular communications, there are several ideas on how to improve the network performance. Two of them are to have base stations with a lot of cooperating antennas and to use higher frequency bandwidths, only available at higher frequencies, in the millimeter wave region. These two concepts seem complicated, and they are! Nevertheless, these novel technologies are two main candidates to be integrated in future fifth-generation (5G) mobile systems, expected to be rolled-out in 2020. When using multiple antennas in a base station (or even in a mobile device), it is desirable to avoid different behavior of the circuits in the system over time caused by temperature, humidity and other environmental factors. This is even more important when many antennas are used, as slight changes in the circuit responses may destroy the performance advantage of using these cooperating antennas. Everything gets even more complicated in higher frequencies, since the environmental effect is stronger. But Maths are really strong, and since all the data in our devices is in fact processed mathematically in a digital form, can't we do something to compensate for this physical (i.e. analog) effects in the mathematical (i.e. digital) domain?. The answer is yes, we can, and this mathematical compensation process is called calibration. For the calibration procedure (or algorithm) to work, it is necessary to know how the many antennas interrelate to one another, for the different frequencies in the frequency band of interest. Hence, some antenna factory characterization must be done beforehand. Since this characterization gets more and more complex with an increasing number of antennas, and the antenna properties may still vary after installation, it is necessary to find more efficient methods of characterization (in particular, efficient estimators of massive MIMO arrays coupling matrix). This Master thesis addresses these two problems associated with environmental changes effects in mm-wave massive MIMO systems and characterization of massive MIMO arrays

Incremental and Modular Context-sensitive Analysis

Context-sensitive global analysis of large code bases can be expensive, which can make its use impractical during software development. However, there are many situations in which modifications are small and isolated within a few components, and it is desirable to reuse as much as possible previous analysis results. This has been achieved to date through incremental global analysis fixpoint algorithms that achieve cost reductions at fine levels of granularity, such as changes in program lines. However, these fine-grained techniques are not directly applicable to modular programs, nor are they designed to take advantage of modular structures. This paper describes, implements, and evaluates an algorithm that performs efficient context-sensitive analysis incrementally on modular partitions of programs. The experimental results show that the proposed modular algorithm shows significant improvements, in both time and memory consumption, when compared to existing non-modular, fine-grain incremental analysis techniques. Furthermore, thanks to the proposed inter-modular propagation of analysis information, our algorithm also outperforms traditional modular analysis even when analyzing from scratch.Comment: 56 pages, 27 figures. To be published in Theory and Practice of Logic Programming. v3 corresponds to the extended version of the ICLP2018 Technical Communication. v4 is the revised version submitted to Theory and Practice of Logic Programming. v5 (this one) is the final author version to be published in TPL

La construcción de subjetividades en el sistema sanitario público de Andalucía (España)

En este artículo presentamos los resultados de una investigación más amplia donde, apoyándonos en el concepto de repertorio interpretativo propuesto por Jonathan Potter y Margaret Wetherell, analizamos el entramado discursivo emergente del Sistema Sanitario Público Andaluz en cuanto a los argumentos-ideas que sostiene. En un artículo previo, identificamos tres grandes grupos discursivos que denominamos como críticos, ontológicos y legitimadores. En esta segunda fase, abordamos las subjetividades construidas desde los anteriores repertorios destacando la presencia de tres categorías de sujetos: los asistenciales, los no asistenciales y los ciudadanos. Señalamos la naturaleza multi-discursiva de la organización y, por tanto, la multi-referencialidad inherente a los procesos de construcción de subjetividades, así como las -posibles- consecuencias organizativas de asumir un tipo u otro de subjetividad. Concluimos planteando la necesidad de adoptar un modelo dialógico de gestión que incluya dicha variedad multi-discursiva del sistema hacia una misma dirección.In this paper, we present the results of a larger investigation in which, relying on the concept of interpretative repertoire put forward by Potter and Wetherell, we analyze the emerging discursive framework of the Andalusian Public Health System in terms of the arguments-ideas behind such framework. In a previous paper, we identified three major discursive groups that we labelled as critical, ontological, and legitimating. At this second stage, we address the subjectivities constructed on the basis of these repertoires and we emphasize three categories of subjects: healthcare, non-healthcare, and citizens. We draw attention to the multi-discursive nature of the organization and, therefore, the multi-referentiality inherent in the processes of subjectivity construction as well as the -potential- organisational consequences of assuming one or another type of subjectivity. We conclude by proposing the need for a dialogic model of management that includes the system's multi-discursive variety toward a same direction

Análisis de la problemática de agencias de transporte y su impacto en la imagen urbana, av. Loreto-Piura, 2022

La presente investigación tuvo como principal objetivo determinar el diagnóstico de las agencias de transporte y su impacto en la imagen urbana de la avenida Loreto-Piura, 2022. La metodología que se propuso fue de tipo básica, con enfoque cualitativo y diseño fenomenológico, cuyos participantes fueron residentes de la zona, peatones, transportistas, pasajeros y expertos en el área; a quienes se les formuló entrevistas semiestructuradas de acuerdo a su percepción de la problemática; de igual forma se aplicó fichas de observación para las 9 agencias de transporte y la imagen urbana de la avenida Loreto, añadiendo a ello también fichas de análisis documental de acuerdo al PDU de Piurac y la ley de desarrollo urbano sostenible, los cuales se validaron previamente por profesionales para dar confiabilidad de validez y aplicación. Agregando a lo anterior, se pudo analizar que el hacinamiento de las infraestructuras evaluadas han deteriorado la imagen urbana de la zona; trayendo problemas como la congestión vehicular, contaminación ambiental e informalidad. Asimismo, la investigación determinó que las agencias de transporte tienen un impacto significativo en la imagen urbana de la avenida Loreto-Piura

Intestinal microbiota and colorectal cancer

Colorectal cancer may be influenced by changes in the intestinal microbiota that affect the mucosa and cause an immune response capable of producing inflammatory effects. Although there are still few studies in this regard, it is necessary to emphasize the need to expand the studies on this topic and to state the usefulness of the new technologies based on metagenomics.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Case study of the intestinal microbiota using the XGN-MBI metagenomic assay

The microbiota of the colon and rectum is the most abundant and diverse of the human body, with a density of up to 1-2 kg of weight and a diversity that exceeds a thousand species. Metagenomics can be defined as the application of modern genomic techniques for the direct study of communities of microorganisms in their natural environment The aim of this study is to prove the usefulness of new technologies based on metagenomics, such as the XGN-MBI assay to realize gut microbiota studies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

SIDEROPHORES FOR SELECTIVE SOLID PHASE EXTRACTION OF STRATEGIC ELEMENTS

All over the world, industrial mining is leaving contaminated areas and dumps that, although being full of valuable metals, have high concentrations of toxic heavy metals that pollute the environment. The development of sustainable alternative biomining and bioremediation processes offers the potential to fully exploit these unexploited mining sites

Lightweight compilation of (C)LP to JavaScript

We present and evaluate a compiler from Prolog (and extensions) to JavaScript which makes it possible to use (constraint) logic programming to develop the client side of web applications while being compliant with current industry standards. Targeting JavaScript makes (C)LP programs executable in virtually every modern computing device with no additional software requirements from the point of view of the user. In turn, the use of a very high-level language facilitates the development of high-quality, complex software. The compiler is a back end of the Ciao system and supports most of its features, including its module system and its rich language extension mechanism based on packages. We present an overview of the compilation process and a detailed description of the run-time system, including the support for modular compilation into separate JavaScript code. We demonstrate the maturity of the compiler by testing it with complex code such as a CLP(FD) library written in Prolog with attributed variables. Finally, we validate our proposal by measuring the performance of some LP and CLP(FD) benchmarks running on top of major JavaScript engines