Enfoque UTE

pp. 1 - 15

Authors: Marco Yamba-Yugsi, Sergio Luján-Mora

We are experiencing constant technological change, which implies that learning and training requirements have been increased, they are increasingly high. One of these changes are Massive Open Online Courses (MOOC). As this is a new technology in our environment, the amount of desertion is high, it is essential to the analysis, to know the reasons of the high amounts of desertion and reduce the dropout of users in MOOC courses. For that, it is proposed to meet the different factors of the problem, for example, previous experience of users in making the MOOC courses, the level of satisfaction in the interaction with platforms that have courses MOOC and satisfaction by the end of a course. Additionally, knowing the user’s profile will make it easier for future courses suit them, although entails increasing the team and tailor a course to users, for the purpose of that they feel supported, intending to follow course and that they possess a new learning experience.

pp. 31 - 45

Authors: Estevan Gómez Torres, Nelson Herrera Herrera, Magí Paúl Díaz

The use of mobile devices has gradually increased. Every day, the number of organizations adopting systems which include some type of mobile payments is becoming bigger. Because of this reason, it is mandatory to have agile and quick systems to guarantee security and reliability, not only for the user but also for the operator. In that way, users will get a high-quality service based on mobile technologies. An analysis of NFC Technology has been made in this paper taking into consideration a proposal of a system development including mobile payments, which could be used in the transportation system of Metro of Quito. To assure the response time and transactional security, the use of cloud computing is recommended.

pp. 62 - 76

Authors: Vicente Merchán, Rocío Rodríguez

Nowadays, leadership and the style of governing have become one of the quality criteria that challenges the Government of Technologies and Information Systems (GoTIS) value-based on public domain. In this aspect, the excellence models and GoTIS standards play a vital role in the success of the organizations due to their usefulness as systems that help the improvement towards the organizational excellence. Two of them are the Ibero-american Model of Excellence in Public Administration and the GoTIS standard ISO/IEC 38500. This paper takes them into account to create a new assessment model of GoTSI, the same one that is validated through the opinion of leaders of technologies and information systems of high-level. The work provides two sub-criteria, eleven dimensions and five components of assessment. This model will allow GoTIS assess itself as a principle of quality and, from there, make an improvement and an organizational change of the processes and GoTIS team decisions. Similarly, it will also help to open the way to the development of new quality criteria from a specific and comprehensive view.

pp. 92 - 106

Authors: Aníbal Rubén Mantilla Guerra

In order to contribute to the treatment of diabetes, which is one of the main causes of death in Ecuador and in the world, a research project is being developed to create equipment that allows the effective control and treatment of this disease. The electronic equipment created for nutrition control, allows the diabetic patient to have information about the amount of calories they should ingest in consideration of their activities and their medical treatment. The mechatronic equipment for the physical exercise of people with diabetic foot, allows the application of therapies according to the severity of the affection. Considering that this is a delicate and complex treatment, the equipment helps the patients to alleviate its discomfort, to decrease the time of recovery and in some cases even to avoid amputation. The construction of the biomedical equipment for the control of nutrition is completed. While the equipment for the treatment of diabetic foot is in a stage of development of prototypes and tests. Both equipment has been conceived and developed with rigorous engineering methods and under quality standards, making an important contribution to research, development of science, technology, and innovation.

pp. 122 - 134

Authors: Juan Pablo Rojas, Julio César Bustos, Diego Ordóñez Camacho

QBus is a system that locates the bus routes circulating in the city of Quito. It consists of a mobile application which uses either Bluetooth Low Energy technology or Quick Response codes to identify the stops. It is based on the location of the user to show the nearest stops and search the available bus routes. The application shows relevant information of each route and, using a digital map, draws its path and the stops it performs. In addition to this, it offers the "How do I get there" functionality that allows the user to search the available bus routes to move from one point to another within the city. In order to comply with this process, QBus performs a search of the bus routes that have stops near the points of origin and destination; this functionality indicates to the user the stop in which he must take the bus and in which it must get off. On the other hand the system consists of a web portal which allows to manage all the information of the application, ie cooperatives, stops and bus routes in a graphical way through the use of the Google Maps V3 API.

pp. 148-159

Authors: Rodrigo Arturo Proaño Escalante, Ciro Napoleón Saguay Chafla, Segundo Bolívar Jácome Canchig, Fanny Sandoval Zambrano

One of the problems that the IT auditor has when expressing an opinion about a finding is the subjectivity that can be due to many aspects, among the main ones: emotional, technical skills or abilities with which this opinion can be right or wrong. This is a major problem because the audit report issued may have distortions of the facts. On the other hand, the development of the expert systems involves capturing the knowledge of the human and transferring it to a computer program in which all the characteristics of this knowledge are emulated and considering a group of rules, the system can make decisions as a human does. Advances in artificial intelligence over the last few years have led to the development of these knowledge-based systems increasing and the results obtained are more real. The use of these systems presents a promising future in the field of computer audit. The objective of this article is to give a general idea of the characterization and use of knowledge based systems, the way they are implemented and their application to the audit of information systems as a tool to help the opinion issue at the moment of realization of an audit.

pp. 172-185

Authors: Alex Cazañas, Andre de San Miguel, Esther Parra

One strategy used to assure that an interface meets user requirements is to conduct usability testing. When conducting such testing one of the unknowns is sample size. Since extensive testing is costly, minimizing the number of participants can contribute greatly to successful resource management of a project. Even though a significant number of models have been proposed to estimate sample size in usability testing, there is still not consensus on the optimal size. Several studies claim that 3 to 5 users suffice to uncover 80% of problems in a software interface. However, many other studies challenge this assertion. This study analyzed data collected from the user testing of a web application to verify the rule of thumb, commonly known as the “magic number 5”. The outcomes of the analysis showed that the 5-user rule significantly underestimates the required sample size to achieve reasonable levels of problem detection.

pp. 201-216

Authors: Germán Oswaldo Cárdenas, Jairo Aponte

Many researchers have highlighted the scarcity of empirical studies that systematically examine the advantages and disadvantages of the use of visualization techniques for software understanding activities. Such studies are crucial for gathering and analyzing objective and quantifiable evidence about the usefulness of proposed visualization techniques and tools, and ultimately, for guiding the research in software visualization. This paper presents a controlled experiment aimed at assessing the impact of a graph-based visualization technique on comprehension tasks. Six common comprehension tasks were performed by 20 undergraduate software engineering students. The completion time and the accuracy of the participants’ responses were measured. The results indicate that on one hand the use of the graph-based visualization increases the correctness (by 21.45% in average) but on the other hand it does not reduce the completion time in program comprehension tasks.

pp. 232-243

Authors: D. Viveros-Melo, M. Ortega-Adarme, X. Blanco Valencia, A. E. Castro-Ospina, S. Murillo Rendón, D. H. Peluffo-Ordóñez

Case-based reasoning (CBR) is a process used for computer processing that tries to mimic the behavior of a human expert in making decisions regarding a subject and learn from the experience of past cases. CBR has demonstrated to be appropriate for working with unstructured domains data or difficult knowledge acquisition situations, such as medical diagnosis, where it is possible to identify diseases such as: cancer diagnosis, epilepsy prediction and appendicitis diagnosis. Some of the trends that may be developed for CBR in the health science are oriented to reduce the number of features in highly dimensional data. An important contribution may be the estimation of probabilities of belonging to each class for new cases. In this paper, in order to adequately represent the database and to avoid the inconveniences caused by the high dimensionality, noise and redundancy, a number of algorithms are used in the preprocessing stage for performing both variable selection and dimension reduction procedures. Also, a comparison of the performance of some representative multi-class classifiers is carried out to identify the most effective one to include within a CBR scheme. Particularly, four classification techniques and two reduction techniques are employed to make a comparative study of multiclass classifiers on CBR.

pp. 257 - 272

Authors: Mónica Moreno-Revelo, Sandra Patascoy-Botina, Andrés Pantoja-Buchelli, Javier Revelo Fuelagán, José Rodríguez-Sotelo, Santiago Murillo-Rendón, Diego Peluffo-Ordoñez

An arrhythmia is a pathology that consists on altering the heartbeat. Although, the 12-lead electrocardiogram allows evaluation of the electrical behavior from heart to determine certain pathologies, there are some arrhythmias that are difficult to detect with this type of electrocardiography. In this sense, it is necessary the use of the Holter monitor because it facilitates the records of the heart electrical activity for long periods of time, it is usually 24 up to 48 hours. Due to the extension of the records provided by the monitor, it is common to use computational systems to evaluate diagnostic and morphological features of the beats in order to determine if there is any type of abnormality. These computational systems can be based on supervised or unsupervised pattern recognition techniques, however considering that the first option requires a visual inspection about the large number of beats present in a Holter record, it is an arduous task, as well as it involves monetary costs. Consequently, throughout this paper we present the design of a complete system for the identification of arrhythmias in Holter records using unsupervised pattern recognition techniques. The proposed system involves stages of preprocessing of the signal, segmentation and characterization of beats, as well as feature selection and clustering. In this case, the technique k-means is used. These steps are applied within the framework of a segment-based methodology that improves the detection of minority classes. Additionally, initialization criteria are considered, which allow to enhance quality measures, especially sensitivity. As a result, it is determined that using k-means with the max-min initialization and a number of groups equal to 12, it is possible to obtain the best results, with values of: 99.36%, 91.31% and 99.16% for accuracy, sensitivity and specificity, respectively.

pp. 287 - 299

Authors: Marcelo V. García, Edurne Irisarri, Federico Pérez

Nowadays, factory automation systems need to cope with very different challenges, such as big data, IIoT, etc. These challenges lead to a new generation of automation systems based on the so-called Cyber-Physical Production Systems (CPPS) globally connected to form a flexible System of Cyber-Physical Production Systems (SoCPPS). CPPSs require acquisition of production system data and smart data processing to extract information to improve the overall system performance. To achieve that it is needed to bridge the gap between the control systems and higher layers. This paper discusses an approach to use the IEC 61499 function block concept to exchange data between plant floor and higher layers using an industrial standard like OPC UA. The OPC UA server offers subscription mechanisms, making possible the integration of several resources residing at plant floor. As it runs on embedded devices, the proposal makes possible to acquire plant information at low cost, enabling at the same time, a component-based design for enterprise plant floor control with independence of the hardware platform used.

pp. 315 - 328

Authors: Oswaldo Moscoso-Zea, Sergio Lujan-Mora

Knowledge Management (KM) is a practice that allows the creation, use, distribution and transfer of knowledge in organizations. Different KM frameworks exist that include business intelligence or enterprise architecture (EA) components for the implementation of KM in organizations. EA tools are used to digitize, relate and visualize the following dimensions of knowledge: organizational structure, business processes, applications and technology. The objective of this paper is to assess the role of EA as a key component in KM and to suggest software evaluation methodologies that can be adapted for the field of EA. For this, an investigation was realized to identify the existing software evaluation methodologies in the market and to filter those that can be adapted for the field of EA. The methodology used for the research was qualitative and exploratory using a case study performed in an international logistic service provider. The case study describes the process done for the selection of the evaluation methodology. Furthermore, it describes the steps for knowledge digitization.

pp. 344 - 357

Authors: Alex Cazañas, Esther Parra

This paper presents a literature review on the topic of web design, specifically with regard to mobile web design. The aim of the review is to identify and analyze major strategies and approaches to design for small-screen-size devices. Three strategies consistently appeared across the reviewed literature, namely, responsive web design, adaptive web design, and separate site. The analysis of these strategies intends to provide a clear understanding of their advantages and disadvantages, in terms of cost and user experience.

pp. 374 - 383

Authors: Xavier Sotomayor, Diego Ordóñez Camacho

The Websockets Shared Virtual Whiteboard, is a system for cooperative work, that allows its users to collaborate remotely, online and in real time. The system provides with a virtual whiteboard acting as a shared workspace where any user´s interactions synchronize automatically and immediately with all the other users. Server side, the system is implemented with the Java Enterprise Edition, mainly using WebSockets technology. Client side, no installing process is necessary, given that any recent browser supporting WebSockets through Javascript, whether on desktop or mobile systems, is able to integrate itself into a working session. The chosen configuration allows the users to hand-draw, and use geometric figures and text boxes; it is possible to save any stage of the working environment to file and reload it for a different session; moreover, a chat tool has been incorporated, which provides with a complementary workspace for adding contextual explanations to the session, everything in a collaborative environment.

pp. 1 - 13

Authors: César del Río

This paper reviews what stage the central banks of the world’s leading economies are at in their study and adoption of distributed ledger technology (DLT) to reengineer their various systems and functions. A brief description of DLT will be given, followed by an analysis of central banks’ publications and pronouncements to determine what each central bank is doing on their journey to DLT adoption. It was found that of the central banks for which information was available, all of them have expressed interest in DLT and have evaluated it to some extent. Nevertheless, no central bank has an operational DLT-based system at this point. This is because some issues remain regarding the speed, cost of processing, security, transparency and privacy, legal settlement finality, scalability and network effects of the technology. As DLT matures, the expectation is that these issues will begin to be resolved.

pp. 26 - 36

Authors: Michael Álvarez González, Lamberto Álvarez Gil, Romel Vázquez Rodríguez

The paper presents the evaluation and the analysis of three types of filter geometry to evaluate the filtration risk in Zaza Reservoir, taking as starting point the historic characteristics of the fluctuation of water levels inside the earth dam. The work is based on the experience of a multidisciplinary team and previous research with bi-dimensional models, using the Finite Elements Method for the solution of basic engineering problems. Also, the results of the installation of a new filter system with a geospatial index are evaluated (under criteria of threats, vulnerability, and risk) with spatial visualization data in a Geographical Information System for thematic maps generation, that represent how much the water level varies inside the dam according to the different filters evaluated.

pp. 46 - 52

Authors: María José Jijón, Teresa Guerrero Villegas, Adriana Barahona, Pablo Aguilar Barriga

Macadamia nut is considered "the queen of nuts", because of its high energy content and nutritional value. Certain types of nuts are considered to be non-commercial due to their color; therefore, the aim of this study was determining a method of surface bleaching using additives that do not affect the taste, smell and texture of the walnut. Color is a sensory quality of food; it’s an indicator and a critical quality factor in fresh and processed products. Three food additives were used as bleaching agents: 1% citric acid for 2 minutes and 3% for 1 minute, 0.1% ascorbic acid for 1 minute and 0.3% for 3 minutes, and 5 and 10% sodium bicarbonate for 1 minute. For all treatments, color analysis, walnut moisture, sensory analysis of odor, taste and texture were carried out. Walnuts were bleached superficially after drying. The results indicate that the best treatment for bleaching macadamia nut is ascorbic acid at 0.3%, with this it is possible to add a more homogeneous and natural color to the nut, free of blackish spots.

pp. 67 - 75

Authors: JE Miranda-Yuquilema, A Marín-Cárdenas, M González-Pérez, D Sánchez-Macías

The aim of this work was to evaluate the physical, microbiological, fibrous and lactic acid changes of cassava silage with cowpea used on biological mix. Fifty kg whole cassava (root, stem and leaves), 20 kg of cowpea flour and 4 L of microbial culture containing Lactobacillus acidophillus, Streptococcus thermophillus and Klyumyces fragilis (L-4 UCLV) were used. The evaluated treatments were: Y100integral cassava (Y100), integral cassava more 20% cowpea (Y+C), and integral cassava more 20% cowpeas and 8% of microbial culture (Y+C+BP). The ensiled material was preserved in sterile glass bottles with wide mouth. A completely randomized design was used. The physicochemical, microbiological, fibrous and lactic acid characteristics were evaluated. For 18 months, the dry matter, crude and true protein, lactic acid contents and the microbial viability was higher (P <0.05) in Y+C+BP treatments from 2 to 18 months. The fibrosity and the pH of the silage was also lower (P <0.05) at the end of the study in this treatment Y+C+BP. It is concluded that with the inclusion of the microbial mix in the cassava silage with cowpea, it is possible to preserve the physicochemical and microbiological properties for 18 months, as well as the values of dry matter, crude and true protein, and lactic acid contents were improved.

pp. 89 - 102

Authors: Luis Hidalgo Aguilera, Jimmy Imbaquingo, Daniel Mideros

An automatic machine has been designed to obtain threads and ribbons through a continuous rotational cutting process. This machine processes plastic bottles used as containers for storage and transportation of soft drinks and non-carbonated drinks with a capacity of three liters. It is a mechatronic design, composed of simple mechanical / pneumatic, electrical and control systems, which allows to process up to fifty bottles per hour. A variety of products can be obtained; from threads with approximately 46.5 m in length and 1.6 mm thick (width) to ribbons with 11.3 m in length and 6.7 mm in width per bottle can be obtained. These products are economic raw material obtained from waste material such as plastic bottles, which are highly polluting elements of the environment due to the small percentage that is recycled especially in Ecuador. This raw material can have applications in some manufacturing processes such as the manufacture of brooms, ropes, baskets, bags, fasteners among others.

pp. 1 - 15

Authors: Segundo M. Espín Lagos, Jorge P. Guamanquispe Toasa, Diana C. Coello-Fiallos, Jorge A. Paredes Zumbana

Shielding was performed on the flanks of teeth of a cane mill by means of the flame thermal projection technique using the Eutalloy 11496 micropulverized alloy. The material of the toner is AISI 1045 steel and the surface of shielding was prepared by the jet process with abrasive material of volcanic nature, in order to achieve an optimum anchorage surface for the alloy. Next, in software, iterations of the thickness of the shield were realized with the purpose of determining its useful life and through the distribution of Weibull we estimated the function of reliability and the function of probability of failure, considering a complete harvest of 240 days.

pp. 27 - 40

Authors: Ortega Holger, Rodrigo Tufiño, Juan Estévez

The present work has the objective of developing a system for the automatic recognition of a playing card on a table, as part of a more general project to create a device to assist the blind in the chance game called “cuarenta”. The aim of this device will be to inform the user about the cards being played, via audio. For this phase of the project the algorithm used was k-NN, trained with a set of alphanumeric synthetic characters. The test set contained photographs taken in controlled lighting conditions, with the card positioned in arbitrary orientations. The parameterization of the algorithm gave a value of 1 as the optimal k, with which a classification error of 5% was obtained in the test set. Only two characters were confused by the classifier, the “A” and the “J”, with 20% and 40% errors each one. The algorithm was implemented in an embedded Raspberry Pi 3 system, obtaining a response time of 5 seconds, including the conversion to audio, and a memory occupation no greater than 60% of the total capacity of the system. These results suggest its applicability in portable devices.

pp. 53 - 67

Authors: Patricio Castillo, Lorena Quinchuela, Paulina Echeverría, Gonzalo Jácome

This work established the conditions of covalent immobilization of trypsin on a Sepharose matrix, which could be applied for the purification of trypsin inhibitors. The higher values of retention of enzymatic activity and immobilized enzymatic activity were obtained with a Sepharose 6B-CL matrix, at room temperature, a pH value of 10.5, an enzymatic load of 25 mg/mL, and a minimum immobilization time of 12 hours, in order to obtain a stable immobilization. The most active trypsin inhibitors were selected through the comparison of, extracts obtained from the seeds of amaranth (Amaranthus caudatus L.), pea (Pisum sativum), lupine or “chocho” (Lupinus mutabilis), bean (Phaseolus vulgaris) and “sangorache” (Amaranthus hybridus L.). The inhibitors were partially purified using centrifugal ultrafiltration, heat treatment, and TCA precipitation. The permeated and retained fractions of “sangorache” were selected as the most active trypsin inhibitors, and they were selectively purified using affinity chromatography in a Trypsin - Glyoxyl - Sepharose 6B-CL matrix. The kinetic characterization showed the presence of two inhibitors; the first one corresponded to a competitive inhibitor, while the second one behaved as a mixed inhibitor.

pp. 1 - 15

Authors: Juan G. Paredes Salinas, Cristian F. Pérez Salinas, Christian B. Castro Miniguano

Studies of composite materials play an important role in engineering, materials, metallurgy and mechanical applications. Polymer reinforced fibers are widely used in the automotive and aeronautical industry because of their benefits such as low cost, noise control, low weight and ease of processing. The objective of this research was to prepare a composite based on 375 (FV) glass fiber with additions of natural cabuya (CF) fiber in laminations of short natural fiber of cabuya (FCO1-30%) and long fiber of the same (FL-30%). The results showed a better mechanical tensile behavior in 7.7% compared to the material commonly used. It was observed that 30% long fiber in a layer order, FV+FC+FV, is a potential reinforcement of the alternative hybrid material for automotive applications. In addition, a balanced reinforcement organization, FV+FC, and micro structural adhesion with the polymeric reinforcement matrix (RP) were evidenced by scanning microscopy. The results of tensile stress and axial deformation of the best combination of composite material, FL-30%, are validated using the finite element method (MEF).

pp. 28 - 40

Authors: Sonia Rosero, Norma Erazo, Miguel Guallpa, Marlene Usigña

The research consisted in evaluating four biostimulants and three substrates for the propagation of Vallea stipularis L.f. in greenhouse conditions. The biostimulants corresponded to: plant hormone rooting (B1), agrohormones 10-10-10 (B2), ESPOCH biostimulant (B3) and Gron Gibb (B4). The substrates consisted of: 50% black soil + 25% peat + 25% sand (S1); 50% black soil + 25% peat + 25% humus (S2) and 50% peat + 50% humus (S3). For the study, it was used a randomized complete design (RCD) with factorial arrangement, it was determined the coefficient of variation and the Tukey test at 5% for the separation of means. The application of the biostimulants in the substrates was done at the time of planting. According to the results obtained, the best biostimulants corresponded to B1 (plant hormone rooting), applied in the seeds for 15 minutes, with which the highest emergency percentage was obtained (70.96%); with biostimulant B2 (agrohormones 10-10-10), applied for five minutes it was obtained 70.67% and with B3 (Gron Gibb) 70.37%. The best substrate for emergence of plants was: 50% peat + 50% humus) with 73.67% of emergence, where the highest plant height and root length were achieved, instead, the ESPOCH biostimulant (microoganisms) reported a 67, 11% emergency.

pp. 56 - 71

Authors: Luis Juiña, Víctor Hugo Cabrera, Salvatore Reina

In the following project, the theory of constraints was applied in order to implement a manufacture CAD-CAM system into the metal mechanic industry processes of polymers injection and blown of polymers. The research showed that the manufacture of the mold with the engraving took 223,17 hours. In the workflow for the manufacture of the mold, a restriction was found in the outsource service of CNC. It took 120 hours of the whole process and represent the 51,47 % the total time of tooling manufacturing. There is also a constraint found in the design time. It was 60 hours that corresponds to 26,88 % of the overall time. In order to reduce the time, a modern system of design in 3D and CAM was established to improve the model process of design and manufacture. A simulation by computational resource was applied to the plastic. The design was changed from 2D to 3D. The implementation was focused in the design. A software was installed to improve the speed of modeling methods with reliable information. In the manufacture of molds, a new CNC machine was acquired with three simultaneous axes to eliminate the outsource service. By acquiring the design system, the working time was diminished in 79% and regarding to the CNC process, the working time was improved in 88%.

pp. 1 - 14

Authors: Melton Tapia, Sandra Arla, Edison Tapia

An agricultural machine of compact size, low cost of manufacture and operation, has been developed for the process of threshing the soft dry corn, originating from the Ecuadorian Andean Region. The simple manufacturing prototype is unique for application in the aforementioned corn species. The main contribution of this development is to provide the farmer with a simple tool that allows him to technify the operation of corn harvesting, an operation that is critical in the harvest stage.

pp. 33 - 43

Authors: L M Rodoni, J F Massolo, A R Vicente

This work evaluates three different conservation methods for red and green fresh-cut peppers. Red and green fruit were processed into sticks and treated as follows: A) water batch immersion (45 oC, 3 min) (TT), B) UV-C radiation (20 kJ m-2) or C) modified atmosphere storage (AM). Other group of pepper sticks were left untreated (control). The sticks were stored at 5 oC during 12 d. Fruit decay, soft-rot and respiratory rate were evaluated during storage. The three treatments were effective to reduce sticks deterioration and the treated fruit evidenced lower respiratory rate at 7 d of storage with respect to control. While the three methods were beneficial to maintain quality, in the red sticks the best results were found with TT and UV, mainly because the AM had less control of the soft-rot at the end of storage. In green sticks all the treatments were equally effective.

pp. 56 - 65

Authors: Osmar Viera Carcache, Leonardo Vinces Llaguno, Kenya Guerrero Goyes, Fabricio Marcillo Vera

This paper presents a computational proposal for the solution of the Cell Planning Problem. The importance of this problem in the area of Telecommunications imposes it as a reference in the search for new methods of optimization. Due to the complexity of the problem, this work uses a discrete relaxation and proposes a mathematical model for the application of the Meta-heuristic Ant Colony Optimization (ACO). For the analysis of the results, 5 instances of the problem of different sizes were selected and the Ants System (AS) algorithm was applied. The results show that the proposal efficiently explores the search space, finding the optimal solution for each instance with a relatively low computational cost. These results are compared with 3 evolutionary alternatives of international reference that have been applied to the same study instances, showing a significant improvement by our proposal.

pp. 78 - 93

Authors: Freddy Yasmany Chávez, Daniel Gálvez Lio

Simulation is a powerful approach in the study of the molecular evolution of genetic sequences and their divergence over time; there are different procedures for the simulation of molecular evolution, but all of them have high computational complexity, and in most cases the genetic sequences have large size, increasing the execution time of the implementations of those procedures. Based on this problem, this paper describes a proposal of parallelization model using CUDA technology and the results of this proposal are compared with its sequential equivalent.

pp. 107 - 120

Authors: Carlos Rosero, Cristina Vaca, Luz Tobar Subía, Fredy Rosero

The self-triggered control produces non-periodic sampling sequences that vary depending on design factors related to stability and performance of the controlled system. Within this framework, two approaches aimed at minimizing a quadratic cost have been developed recently, considering an optimal performance and pursuing the same control objective; each approach follows a different sampling rule. One approach is based on maintaining the current control value as long as possible, while an optimal performance threshold is not passed. The other approach is based on the generation of a piecewise control signal, which approximates a continuous optimal control signal subject to certain constraints. This article presents a comparative study between the two approaches, providing a useful insight for conducting future research. Control performance and resource utilization were considered as metrics of interest and to evaluate them, the average sampling interval and the standardized cost were taken into account. It was shown that the different search space of each approach poses a challenge to design an equitable framework of comparison, and that both approaches exceed the periodic sampling.