Journal of Computer Science and Technology <p>The Journal of Computer Science and Technology (JCS&amp;T) is semiannual, open access, and peer-reviewed International Journal promoting the dissemination of original research and technological implementation experiences in the areas of Computer Science, Engineering, and Information Systems</p> <p>Specific topics of interest include: Intelligent Systems; Artificial Intelligence; Semantic Web; Algorithms; Cluster, Grid, Cloud &amp; Accelerator Computing; Fault-Tolerant System; Parallel Architectures; Computer Graphics; Virtual Reality; Human-Computer Interfaces; Image Processing; Technology &amp; Education; E-Learning; M-Learning; Software Engineering; Quality and Software Metrics; Real-Time Systems; Signal Processing; Data Bases; Data Mining; Big Data; Operating Systems; Network Architecture and Configuration; Security; Industrial Systems; Robotics; E-Government; Modelling &amp; Simulation and Computer Science Applications.</p> en-US <header class="entry-header"></header> <div class="entry-content">&nbsp; <h4><strong>Copyright and Licensing</strong></h4> <p>Articles accepted for publication will be licensed under the&nbsp;<a href="" target="_blank" rel="noopener">Creative Commons BY-NC</a>. Authors must sign a non-exclusive distribution&nbsp;<a href="">agreement</a>&nbsp;after article acceptance.</p> </div> (Editorial Team) (Editorial Team) Thu, 10 Oct 2019 00:00:00 +0000 OJS 60 Automatic suggestions to improve the quality of scatterplots during its creation <p>The visualization process is a very complex exploration activity and, even for skilled users, it can be difficult to produce an effective visualization. The result of such process depends on the user's decisions along it. One way to improve the probability of achieving a useful outcome is to assist the user in the configuration and preparation of the visualization. Our proposal consists in live suggestions on how to improve the visualization. These live suggestions are based on the user decisions, and achieved by the integration of semantic reasoning into the visualization process. In this paper, we present a case study for scatterplots visualization that combines ontologies with a semantic reasoner and helps the user in the generation of an effective visualization.</p> Dana Urribarri, Martín L Larrea, Silvia M Castro Copyright (c) 2019 Dana Urribarri, Martín L Larrea, Dr., Silvia M Castro, Dra. Thu, 10 Oct 2019 08:02:07 +0000 IaaS Cloud as a virtual environment for experimentation in checkpoint analysis <p>Cloud Computing offers the possibility of computing resources, allowing remote access to software, storage and data processing through the Internet. Infrastructures as a Service (IaaS), it is a flexible space which can be used as an experimental environment, in which experiments can be carried out similar to a real environment, such as in a cluster can be carried out. Before making installations and changes in a production cluster or select resource in the cloud, it is important to analyze the impact of this change. For this reason we propose using the cloud to carry out the study of previous viability. In this paper, we observe the viability of using the cloud to analyze the behavior of the Checkpoint as one of the Fault Tolerance strategies, establishing the differences that exist in the information generated in a real environment (cluster) and a virtual environment (cloud). The results obtained show that due to the variability of the cloud, the impact on the benefits cannot be analyzed. However, the cloud is suitable for extracting the spatial and temporal behavior pattern of the checkpoint, which helps to characterize it and this will help us to know the right configuration and the development of methodologies and tools that simulate and predict the execution of the checkpoint in a real environment.</p> Betzabeth León, Pilar Gomez-Sanchez, Daniel Franco, Dolores Rexachs, Emilio Luque Copyright (c) 2019 Betzabeth León, Pilar Gomez-Sanchez, Daniel Franco, Dolores Rexachs, Emilio Luque Thu, 10 Oct 2019 08:13:20 +0000 Educational value of Systematic Mapping Studies: A replication study. <p><span class="fontstyle0">Contribution</span><span class="fontstyle1">: The goal of this study is to validate the results of a prior study on the educational value of systematic mapping studies (SMS) and evaluate the possibility of generalizing those results to similar contexts. </span><span class="fontstyle0">Background</span><span class="fontstyle1">: since the inception of the Evidence Based Software Engineering (EBSE) paradigm in 2004, few studies have aimed at evaluating their impact in the academic field, and the educational values that SMS can offer to the students. In 2010, three renowned researchers presented an article on this subject at ICSE'10. The study made interesting contributions. We believe that, after 8 years, a replication of that study can be useful to assess the original findings and to guide future educational interventions. </span><span class="fontstyle0">Research Questions</span><span class="fontstyle1">: What educational value does a SMS provide? </span><span class="fontstyle0">Methodology</span><span class="fontstyle1">: a replication of a multi-case holistic study. </span><span class="fontstyle0">Findings</span><span class="fontstyle1">: This replication confirms all but two of the results from the original work. The differences may be due to slight variations in the context. The experience of undertaking an SMS provided the students with both research skills and a broad understanding of a research area. We encourage other researchers to replicate this study, to gain further insights into the educational value of this method.</span></p> Jose L. Barros-Justo, Nelson Martínez-Araujo, David N. Olivieri, Alejandro González-García Copyright (c) 2019 Jose L. Barros-Justo, Nelson Martínez-Araujo, David N. Olivieri, Alejandro González-García Thu, 10 Oct 2019 08:18:34 +0000 The Power Cepstrum Calculation with Convolutional Neural Networks <p>A model of neural network with convolutional layers that calculates the power cepstrum of the input signal is proposed. To achieve it, the network calculates the discrete-time short-term Fourier transform internally, obtaining the spectrogram of the signal as an intermediate step. The weights of the neural network can be calculated in a direct way or they can be obtained through training with the gradient descent method. The behaviour of the training is analysed. The model originally proposed cannot be trained in a complete way, but both the part that calculates the spectrogram and also a variant of the cepstrum equivalent to the autocovariance that keeps a big part of its usefulness can be trained. For the cases of successful training, an analysis of the obtained weights is done. The main conclusions indicate, on the one hand, that it is possible to calculate the power cepstrum with a neural network; on the other hand, that it is possible to use these networks as the initial layers of a deep learning model for the case of trainable models. In these layers, weights are initialised with the discrete Fourier transform (DFT) coefficients and they are trained to adapt to specific classification or regression problems.</p> Mario Alejandro García, Eduardo Atilio Destéfanis Copyright (c) 2019 Mario Alejandro García, Eduardo Atilio Destéfanis Thu, 10 Oct 2019 08:21:26 +0000 A Case Study of Forecasting Elections Results: Beyond Prediction based on Business Intelligence <p>In the field of data analysis, it is common not to distinguish clearly between prediction and forecast. Although the results of both processes may tend to converge, the mechanisms used in each case tend to be completely different. Prediction has to do with statistical extrapolation and estimation and forecasting can consider expert judgments on the subject. A methodology is proposed to carry out this latter task, with a mechanism that uses both historical and current data with the judgement of an expert. The methodology is applied to the case study of the Spanish general elections of April 2019.</p> Antonio Lorenzo Sánchez, Jose Angel Olivas Copyright (c) 2019 Antonio Lorenzo Sánchez, Jose Angel Olivas Thu, 10 Oct 2019 08:30:13 +0000 Applying an Improving Strategy that embeds Functional and Non-Functional Requirements Concepts <p>Organizations should set and reach business goals for varied purposes using the suitable strategies. Basically, a strategy specifies the activities, methods and another related resources that should be considered in order to achieve a given goal purpose. Goal purposes and their associated strategies can aim at evaluating, testing, developing, or maintaining some entity. Some concrete evaluation purposes such as to understand or monitor can be achieved by strategies embracing non-functional requirements definition, measurement, evaluation and analysis activities. Other specific evaluation purposes such as to improve or control also imply changing the target entity; therefore, strategies should embrace functional requirements definition activities as well. Moreover, specific development and maintenance purposes always involve functional requirements. In this work, we relate business and information need goals with functional and non- functional requirements concepts, which are paramount for well-defined strategies. Therefore, we specify vocabularies for them, and illustrate the applicability of an improving strategy –which embeds these concepts- in the context of a running example. Having well-structured vocabularies serving as common ground for diverse strategies may promote a more effective operationalization of projects dealing with evaluation, testing, development and maintenance goal purposes.</p> Pablo Becker, Guido Tebes, Denis Peppino, Luis Olsina Copyright (c) 2019 Pablo Becker, Guido Tebes, Denis Peppino, Luis Olsina Thu, 10 Oct 2019 09:04:57 +0000 Implementation of an Open Source Based Augmented Reality Engine for Cloud Authoring Frameworks <p>In recent years the technology around Augmented Reality has grown considerably, in particular on cloud based. In this paper we present a pipeline model and sample implementation that shows how an Augmented Reality engine can be built by leveraging advances in open source algorithm implementations. We also show how such an engine can be effectively integrated with cloud authoring tools to take advantage of the network connectivity and its computing power.</p> Nahuel Mangiarua, Jorge Ierache, Marı́a José Abasolo Copyright (c) 2019 Nahuel Mangiarua, Jorge Ierache, Marı́a José Abasolo Thu, 10 Oct 2019 09:16:04 +0000 An Architecture Model for a Distributed Virtualization System <p>The Thesis is about an architecture model for a Distributed Virtualization System, which could expand a virtual execution environment from a single physical machine to several nodes of a cluster. With current virtualization technologies, computing power and resource usage of Virtual Machines (or Containers) are limited to the physical machine where they run. To deliver high levels of performance and scalability, cloud applications are usually partitioned in several Virtual Machines (or Containers) located on different nodes of a virtualization cluster. Developers often use that processing model because the same instance of the operating system is not available on each node where their components run. The proposed architecture model is suitable for new trends in software development because it is inherently distributed. It combines and integrates Virtualization and Distributed Operating Systems technologies with the benefits of both worlds, providing the same isolated instance of a Virtual Operating System on each cluster node. Although it requires the introduction of changes in existing operating systems, thousands of legacy applications would not require modifications to obtain their benefits. A Distributed Virtualization System is suitable to deliver high-performance cloud services with provider-class features, such as high-availability, replication, migration, and load balancing. Furthermore, it is able to concurrently run several isolated instances of different guest Virtual Operating Systems, allocating a subset of nodes for each instance and sharing nodes between them. Currently, a prototype is running on a cluster of commodity hardware provided with two kinds of Virtual Operating Systems tailored for internet services (web server) as a proof of concept.</p> Pablo Andrés Pessolani Copyright (c) 2019 Pablo Andrés Pessolani Thu, 10 Oct 2019 09:18:57 +0000