Search

The high levels of waste cellulose mud in paper production represent a severe environmental problem regarding its final disposal as a waste by-product. The accumulation of paper sludge and its possible recycling should be focused on its reuse in primary materials or those of continuous use that mitigate its environmental impact. This research was developed to characterize a clay material used in civilian construction with Eco-Efficient properties (hollow ceramic bricks), incorporating waste from paper factories (paper sludge or cellulose sludge) without affecting its mechanical response in comparison with traditional materials, but with the use and advantages of the utilization of residual materials. For this purpose, a physical-chemical characterization of the paper sludge was carried out, accompanied by a physical-mechanical characterization for the Non-structural block obtained with the inclusion of the sludge, in accord with dosages of 0%, 11.1%, 12.5%, 14.3% 16.7% and 20%. As a result, the organic and inorganic byproducts present in the paper waste byproducts were obtained, and the hollow ceramic bricks showed an increase in their mechanical compression capacity under considerable variations in coloration and size. [ABSTRACT FROM AUTHOR]

In humankind's history, many natural and man-made disasters have happened and will continue to happen. In a post-disaster scenario, many processes and actors must be organized to provide the needed supplies to the affected people. Although it is similar to a supply chain, it is called Humanitarian Logistics in a disaster context. Many papers present centralized approaches to organizing different aspects of humanitarian logistics. However, a centralized approach is not always appropriate due to the dynamics and uncertainty present in a post-disaster scenario. This paper describes a distributed approach based on Multiagent Systems (MAS) to organize the elements of humanitarian logistics in a post-disaster scenario (MAS-HL). Intelligent agents in the MAS-HL, represent real-world elements, such as affected zones, distribution centers, donors, and trucks. The agents negotiate among themselves using a Contract-Net Protocol (CNP) to organize the operations of the elements represented. Due to dynamics and uncertainty in a post-disaster scenario, the agents must reorganize the operations of the elements. The MAS-HL is evaluated by simulating and evaluating a case study focused on bottled water delivery in post-disaster scenarios, they represent when major changes occur. The computational results confirmed that the MAS-HL quickly generates plans to organize the elements of humanitarian logistics and reorganize the plans when the environment changes. [ABSTRACT FROM AUTHOR]

The rapid growth of the renewable energy market has provoked pressing challenges because of the significant financial resources required, highlighting the need for marketing of the electricity sector. The role of brand identity influences on customer image that affects demand changes and financial resources used by SMEs in the electricity sector. This paper presents a dynamic model-based analysis to understand better the role of brand identity in creating value in SMEs. The simulation model aims to assess alternative strategies of brand identity to support SMEs in the electricity sector to promote efficiently value creation. Simulation results show that the high customer value perception allows aligning the electricity utility industry to create more value. This dynamic perspective presents a new point of view that contributes to managers and policymakers in analysing the relationships of stakeholders. Thus, the paper will give some insights on the design of an alternative business model based on non-conventional renewable energy. [ABSTRACT FROM AUTHOR]

This paper provides a numerical assessment of the ductile fracture of the AA6101 and AISI 4340 alloys using the Lemaitre and Gurson models. The simulations were carried out to verify the evolution of the accumulated plastic strain at fracture, assuming the high range of the triaxiality ratio, applying monotonic tensile loads on smooth and notched cylindrical specimens. The numerical strategy was structured for the Lemaitre and Gurson models, from establishing a non-linear system of equations using an implicit integration algorithm and solving the non-linear equation system using the Newton-Raphson method. When assessing the numerical and experimental results, it was observed that the cumulative plastic strain at the fracture decreases with the increasing levels of the triaxiality ratio for both alloys and models. On the one hand, the Lemaitre model was more optimistic than the experimental results. On the other hand, Gurson's model proved to be more conservative in its prediction of ductile fracture. Regarding determining the fracture onset, in general, both models showed good predictive capacity. However, the numerical results for the aluminum alloy presented more in agreement with experimental data than for the AISI 4340 alloy. In the end, assuming the determination of the level of displacement at fracture, the Gurson's model has the best performance. In this sense, for a high level of triaxiality ratio, the Gurson porous material can be recommended to describe the mechanical behavior of the material at fracture. [ABSTRACT FROM AUTHOR]

The Ball Mill Abrasion Test (BMAT) is a laboratory experiment used to measure the resistance of materials under high-stress abrasion conditions. This test, however, has yet to be standardized. In this work, statistical theory determines the optimal number of spheres per material to be included in BMAT. This theory and the optimization method presented in this paper show that the optimal number of spheres for the usual experimental conditions is six. Finally, it is shown that if the optimization process is extended over a broader range of experimental conditions, the optimum number of spheres per material is also six. [ABSTRACT FROM AUTHOR]

Enterprise resource planning systems (ERPs) have become an essential management tool for large and small companies alike. Although several papers on ERPs have been published in recent decades, only some studies have focused on user satisfaction during post-implementation. Based on the theories of technological acceptance and task-technology fit, we examine how the interrelationship of individual attitudes and matching between task and ERP affects user satisfaction in a public university that adopted an SAP-ERP. We distributed a questionnaire and analyzed the responses of 126 users using a partial least squares structural equation modeling (PLS-SEM model). Results show that perceived utility and overall benefits significantly predict user satisfaction. Moreover, overall benefits are influenced by the perception of efficiency in the task, improvements in coordination, and strategic alignment. Customization of the system had no statistical effect on the model. [ABSTRACT FROM AUTHOR]

Queuing theory is a set of mathematical models that explain systems where customers wait in a row to receive service under specific selection criteria. The models allow analyzing the system's behavior and finding a "solid-state" that achieves an optimal use of resources. However, there are no models developed for each type of behavior of the distribution of customer arrival times or customer service times in the system in many real situations. In these cases, it is recommended to work the queuing systems through simulation by discrete events. This paper proposed applying the queue system principles in a container loading and unloading process in the port of Barranquilla (Colombia). For this, the entry and exit elements of the import and export processes of goods were identified. Each process's actual loading and unloading times were consolidated and analyzed to identify the most adjusted probability distributions for these times. The simulation process included the random generation of the times between arrivals and the service times to 30 simulations made in each process to study the evolution of the queuing system over time. The results demonstrated the utility of the proposed approach to obtain and analyze the performance measures of the processes. [ABSTRACT FROM AUTHOR]

The progress of Information and Communication Technologies has significantly promoted the relationships among people of different geographical regions. Under this novel context, new settings of software development teams arise, known as virtual teams. The objective is to identify, evaluate and synthesize reported research about the measurement of interpersonal trust (IpT) in virtual software teams (VST). We conducted a systematic review of the peer-reviewed literature published in the research area until July 2019. We reviewed 747 papers, of which 11 primary studies were considered relevant for the investigation. Most studies (8 of 11) use instruments of direct measurements (interviews and questionnaires) to measure interpersonal trust. Studies that use indirect measurements focus on different characteristics of the virtual software team (agreeableness, affective lexicon, delegation, positive tone, acceptance of knowledge, etcand others). Recomiendo: Most studies (10 of 11) report that interpersonal trust measurements improve performance aspects of virtual software teams. Among them the willingness to share information, goodwill towards others, motivation, collaboration, and effectiveness. Most studies use questionnaires or interviews, but we believe that software repository mining to obtain IpT levels will be an auspicious research trend in the future. The attribute more used to assess IpT is the developer opinion. Other attributes used are emotions, interactions between developers, biography, acceptance of knowledge, and assignment of tasks. IpT measurement is a useful tool for decision-making in VTS management, especially in agile software processes, but there is little evidence of its use. [ABSTRACT FROM AUTHOR]

Software programming for concurrent execution is not a simple task. The main issue related to this work is the lack of visibility of the multiple and parallel execution over the threads. Multi-core processor technology is a reality nowadays, and the only way to use modern hardware at its full capacity lies in the use of concurrent software. In this paper, a new 3D framework is presented, based on hand gestures that manipulate multiple threads of execution and deal with the visibility issues, using a 3D programming environment, including a set of experiments to evaluate the methodology's performance. [ABSTRACT FROM AUTHOR]

This paper aims to present a Business Intelligence dashboard with a goal-oriented approach. A case study was developed taking as context of analysis a Cuban college. The requirements of the dashboard were modeled by using aspects of social modeling and the language i*. The models obtained allowed analyzing the goals, tasks and resources necessary to accomplish the requirements of the dashboard, as well as to align the metrics of the dashboard with the goals of the decision-maker. The resulting dashboard allowed visualizing and monitoring the performance of students to support decision-making at a tactical level. The contribution of this paper is a goal-oriented approach for modeling the requirements of dashboards and for extracting the metrics of dashboards aligned with the goals of decision-makers. [ABSTRACT FROM AUTHOR]

This paper presents the development of a modular mobile robot platform for multiple purposes and its adaptation into a beach cleaner setup. The robot has a robust construction allowing it to endure several sorts of environments. In the presented configuration, the developed robot is able to autonomously collect cans using an excavator-like claw. In addition to detailing the system's design and construction, this paper presents the description of the developed embedded electronics modules, a motor closed-loop speed control system and the optical flow algorithms that allows the computer vision system to detect and avoid obstacles and track the cans to be collected. [ABSTRACT FROM AUTHOR]

Hospital readmission is considered a key research area for improving care coordination and achieving potential savings. This is important because hospital readmissions can have negative consequences in terms of good health and recovery for patients. It is thus important to significantly reduce such readmissions. Unfortunately, there isn't a one-size-fits-all solution to preventing hospital readmissions. There are many variables outside of hospitals' direct control, such as social determinants and patient lifestyle factors, impacting readmissions. Although several studies have been undertaken to investigate 30-day readmissions, predicting revisits in shorter intervals (e.g., within 15 days after discharge) is highly needed to capture hospital-attributable returns better and develop more effective improvement plans. Hence, the aim of this paper is three-fold: i) to develop a comprehensive experimental study for identifying factors affecting 15-day readmission risk, ii) to classify patients according to the risk of 15-day readmission using logistic regression, and iii) provide general recommendations to reduce the 15-day readmission risk considering different predictors. To this end, the patients' characteristics were first described. Then, the significance of potential predictors, their interactions, and their effects were assessed. After this, a logistic regression model was derived to predict the likelihood of 15-day readmission in each patient. Finally, general recommendations were provided to reduce 15-day revisits. A real case study in Colombia was considered to validate the proposed methodology. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model validated with experimental data for the analysis of biodiesel production from microalgae biomass, using as an alternative substrate industrial wastewater. System dynamics methodology was used for its development, by which the mathematical model representing the production of biomass and lipids was obtained, as well as the generation of biodiesel from microalgae oil. Biomass generation was represented by a basic growth model which assumes that there is no restriction for nutrients. This biomass generates a quantity of lipids according to the nitrogen-phosphorus ratio present in the industrial effluent, with higher production under low nitrogen concentration. Finally, these lipids are transformed into an amount of fatty acid methyl-ester that varies at a rate of transesterification. Validation and calibration of model behavior, was performed with experimental data obtained in tests of the Scenedesmus sp. microalgae growth in wastewater from the textile and tanning industry. The simulation of the model represented with significant approximation the growth and the generation of lipids for Scenedesmus sp. Furthermore, it was shown that wastewater from tanneries would allow increased production of biodiesel by favoring the generation of biomass rich in amount of lipids. Thus, the proposed model can be a useful tool for assessing the production of biodiesel using industrial wastewater as alternative growth substrates. [ABSTRACT FROM AUTHOR]

A theoretical framework based on the Borrmann classification and the Japanese gastric cancer classification is proposed in order to qualitatively assess the stomach cancer from the three-dimensional (3-D) images obtained using multi-slice computerized tomography (MSCT). The main goal of this paper is to demonstrate through visual inspection, the MSCT capacity to effectively reflect the morphopathological characteristics of the stomach adenocarcinoma types. The idea is to contrast the pathological theoretic characteristics with those that are possible to understand from MSCT images available in clinical datasets. This research corresponds to a study with a mixed approach (qualitative and quantitative), applied to a total of 46 images available for patients diagnosed, from the data collection included of the Cancer Genome Atlas Stomach Adenocarcinoma (TCGA-STAD). The conclusions are established from a comparative analysis based on the document review and direct observation, the product being a matrix of compliance with the specific qualities of the theoretical standards, in the visualization of images performed by the clinical specialist from the datasets. A total of 6210 slices from 46 MSCT explorations are visually inspected, and then visual characteristics are contrasted with respect to the theoretic characteristics obtained from the cancer classifications. These characteristics match into about 96% of images inspected. The approach effectiveness measured using the positive predictive value is about 96.50%. The results of the images data also show a sensitivity of 97.83%, and specificity of 98.27%. MSCT is a precise imaging modality in the qualitative assessment of the staging of stomach cancer. [ABSTRACT FROM AUTHOR]

The routing performance of the In Mobile Ad-hoc Networks (MANETs) depends on the individual nodes that represent the network. In this paper, a new protocol based on self-monitoring (agent-based) and following the Ad Hoc on Demand Distance Vector (AODV) Routing Algorithm is presented. This protocol may be called Agent-Based Ad Hoc on Demand Distance Vector Routing Algorithm (AB-AODV) Protocol for MANETs. The main objective of the proposed method is to manage trusted information locally with minimal overhead in terms of extra messages and time delay. This objective is achieved through installing in each participating node in the network a multi-agent system. Multi-agent system consists of two types of agents: monitoring agent and routing agent. A new mathematical and more practical objective model for measuring the trust value is introduced. This model is weighted by both the number and size of routed packets to react to the selective forwarding behavior of a node. The performance evaluation via simulation using NS-3 shows that the proposed protocol is better than standard AODV. The simulation is done under a variety of environmental conditions such as the number of malicious nodes, host density, and movement rates. [ABSTRACT FROM AUTHOR]

The connection of distributed energy resources (i.e., distributed generation and energy storage) and some special loads (e.g., electrical vehicle) raises new challenges in distribution system analysis. Intermittent and non-dispatchable generation units, time-dependent or asymmetrical loads require capabilities that until very recently were not available in distribution software packages; for instance, capabilities for probabilistic and time mode simulations. This paper presents the work made by the authors to adapt OpenDSS, a freely available distribution simulator, in order to perform these types of studies taking into account that the model of an actual distribution system is usually very large and complex. A goal of the paper is to present the usage of OpenDSS as either a stand-alone tool or as a COM DLL driven from MATLAB. Several applications have been developed to obtain yearly curve shapes aimed at representing time-varying loads and renewable energy sources (sun, wind) and to run OpenDSS in a distributed computing environment (e.g., multicore installation). [ABSTRACT FROM AUTHOR]

Inventories represent stocks of goods necessary for operations of sales or manufacturing in a company. These allow to the companies meet their sales levels, while representing an opportunity to the cost control and the decision-making. This paper presents an optimization approach to minimize the inventory costs in probabilistic inventory models of independent demand. The approach has been validated for set the policy optimal of inventories with probabilistic demand within a company that markets disposable products. The established policy aims to minimize the inventory costs by using the standard deviation of the historical data, the mean deviation of forecast errors and the mean deviation of the historical data. For the determination of the economic order quantities, three types of products were selected, taking historical sales data. Likewise, different forecasting methods were used, selecting the one that minimizes the mean squared error for the forecasted demand. The proposed methodology is practical and easy to use in companies where inventories have probabilistic and independent demand. Also, the proposed approach allowed optimize the costs related to holding costs, ordering costs and safety stock costs. [ABSTRACT FROM AUTHOR]

The characterization of steel fiber reinforced concrete with dry consistency require greater inspection the account of the particularities in the process of mixing, molding and densification, thus this paper aims to propose a methodology combined of densification by manual and mechanical means and the mechanical characterization by the three-point flexural testin prismatic dry cast steel fiber-reinforced concrete specimen. In a qualitative way, the densification-combined methodology provided a smooth surface on the specimen appearance and a reduction of voids due to trapped air. In the flexural test we verified slip-softening and slip-hardening, respectively, to lower and higher reinforcement indexes and theoretical volumes. By the analysis of variance of the results and the database we found out that there was no significant statistical difference to the analyzed residual strength for the combination of the test method (RILEM), consistency (plastic), type (hooked end) and form (glued), when the comparison is made by quadruple association. [ABSTRACT FROM AUTHOR]

Permeable friction course (PFC) mixtures are a special type of hot mix asphalt (HMA) mixtures characterized by high total air voids (AV) content values to provide high permeability and noise reduction effectiveness, while high surface texture conditions can be ensured. Recent advancements in materials and HMA mixture evaluation led to increase the use of PFC mixtures over the last two decades as an alternative to improve highway safety and noise reduction. However, these developments on PFC mixtures generate the need for a comprehensive review to facilitate corresponding practical implementation. Consequently, the main objective of this paper is to provide a summary of research findings on PFC mixtures to improve the conception, design, and use of these HMA mixtures. In this context, the paper includes aspects related to advantages and limitations, volumetric properties, structural life, mixture distresses, and functionality of PFC mixtures. The aspects summarized provide a baseline for improvement of the current design and conception of PFC mixtures and offer guidelines for some future research developments. [ABSTRACT FROM AUTHOR]

The internal structure of the hot mix asphalt (HMA) mixtures plays an important role in the response and performance of these paving mixtures. The objective of this paper is to conduct a quantitative comparison of the differences in internal structure --evaluated in terms of the air voids (AV) characteristics-- of four HMA mixture types. Although the performance assessment of the HMA mixtures analyzed is out of the scope of this paper, the comparison conducted is useful to improve the understanding of the differences exhibited, at the macroscopic level, by different HMA mixture types. The AV characteristics (i.e., content, distribution, and size) were computed based on analysis of X-ray Computed Tomography images obtained from specimens compacted using the Superpave gyratory compactor (SGC). Corresponding results and analysis suggested that the mixtures studied presented irregular vertical distributions of total AV content and AV size, with a degree of heterogeneity that is mixture dependent, but not specimen dependent. Consequently, the specific laboratory procedure used to obtain SGC compacted specimens should be designed based on both the specimen height and mixture type. In addition, the comparative analysis also indicated that the mixtures considered as "difficult to handle" in the laboratory (i.e., PFC mixtures fabricated with asphalt rubber) did not exhibit the highest degree of heterogeneity in their internal structure. This conclusion suggests the need for proper handling of all types of HMA mixtures to get true replicate specimens. [ABSTRACT FROM AUTHOR]

In this paper, a simplified analytical model for the design of friction piles foundations in an environment that is prone to regional subsidence is presented. The model is based on Mindlin's equations and was originally proposed by Reséndiz and Auvinet. Some important modifications of the original version based on the results obtained from numeric analyses have been introduced. In this new version, negative skin friction is evaluated taking into consideration initial and future effective stresses conditions and not only the limit shear strength of the soil in contact with the pile system. The model was validated with results previously obtained by the authors using the Axisymmetric Finite Element Method. In spite of the differences observed during such validation, it was possible to conclude that a reasonably good match exists between both models. [ABSTRACT FROM AUTHOR]

The photovoltaic solar energy is a renewable energy source that is growing in the Brazilian energy scenario, mainly after the approval of Normative Resolution (REN) n° 482/2012 of the Brazilian Regulatory Agency (ANEEL). This REN establishes the general conditions of micro and mini-generation access to the distribution system (distributed energy) and the energy compensation system (net metering). The evolution of photovoltaic solar technology coupled with the new perspective created by REN 482/2012, made many consumers unities to install a photovoltaic system (PVS). However, many aspects can be considered, for example, characteristic of the installation place, solar potential of the region, distribution network (DN), connection rules, as well as the financial economic analysis of installation and its maintenance. Thus, this paper presents an analysis of PVS installation in a commercial consumer unit in Florianopolis - Brazil, considering a system design to be connected to the local DN and their financial economic analyses. Different scenarios were simulated, ranging the aspects that may influence the investment return, like the self-consumption percentage, the tariff variations over the years, the tax incidences on the generated energy, as well as the variation in the PVS size. As a result, it can be seen in scenarios that the change in the tariff over the years, the form of acquisition through financing and the possibility of energy sales can be the things that most influences the return on investment. However, in Brazil, PVS financing and energy sale are not regulated to the consumer unit yet. [ABSTRACT FROM AUTHOR]

This paper presents a document representation strategy and a bio-inspired algorithm to cluster multilingual collections of documents in the field of economics and business. The proposed approach allows the user to identify groups of related economics documents written in Spanish and English using techniques inspired on clustering and sorting behaviours observed in some types of ants. In order to obtain a language independent vector representation of each document two multilingual resources are used: an economic glossary and a thesaurus. Each document is represented using four feature vectors: words, proper names, economic terms in the glossary and thesaurus descriptors. The proper name identification, word extraction and lemmatization are performed using specific tools. The tf-idf scheme is used to measure the importance of each feature in the document, and a convex linear combination of angular separations between feature vectors is used as similarity measure of documents. The paper shows experimental results of the application of the proposed algorithm in a Spanish-English corpus of research papers in economics and management areas. The results demonstrate the usefulness and effectiveness of the ant clustering algorithm and the proposed representation scheme. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present the advances in the implementation of the Smart Grids (SGs) in the whole world span and the prospectus of Colombia towards the implementation of new solutions. Mainly considering those technological developments and advances made in the electrical networks, related with the use of software for their analysis and management in different scenarios, to optimize the electrical system management and operation upon the new challenges that we have currently. For this matter, first is presented the theoretical framework which the SGs are focused and the advances in recent years, analyzing the metering, communication, security and control systems in comparison with future projected solutions. Subsequently, it is collected the general information about the actual projects that use solutions, as ETAP Real Time, which involves SGs implementation. At the same time, pointing out the advantages and disadvantages that the diverse implemented solutions possess, highlighting the technical and technological gaps regarding the consulted theory and the current state-of-the-art. Finally, the ETAP Real Time solution is presented as an integral alternative to help resolve the worldwide and Colombia implementation challenge of SGs. [ABSTRACT FROM AUTHOR]

This paper presents an example of how Model-Driven Engineering (MDE) can be applied to the development of tools for reverse engineering and program comprehension. The tool CodeCrawler was selected as an example; in particular, the polymetric view feature was computed using MDE techniques. To this end, two metamodels were proposed (source and target) and meta-level transformations that were used to deduce the information of a polymetric view associated to any software project (source code). The technologies selected to develop the example were those related with the Eclipse Modeling Project, specifically the ATL and the KM3 languages. The approach used in this paper to obtain the implementation can be used to develop all the features of a MDE-oriented software comprehension tool, obtaining a domain-oriented implementation. [ABSTRACT FROM AUTHOR]

The quantum relationship m0c² = ħ∣ω0∣ may be regarded as the equivalence between two expressions for the rest energy of the particle, if ω0 is considered as the spin angular velocity of the particle in its rest frame. The invariance of the relativistic space-time interval ds² =c² dt² - dr² to such a spin motion (space isotropy) leads to the spin momentum Sz ħ/2 for all structureless particles irrespective of their mass values. The inertia is an intrinsic property due to the spin motion of the particles. The signs of the mass values occurring in the solutions of the Dirac equation might be related to the orientation of the spin motion, as suggested by the fundamental relationship ±m0c² = ±ħ∣ω0∣. In addition, it deals with the electron, and more specifically with two key properties: its complex wavefunction and its intrinsic spin. In the standard interpretation, there is no clear real-space picture of what is oscillating in the wave, or what is rotating in the spin. Indeed, it is generally believed that no simple model of rotation can account for the spin of the electron. On the contrary, the present paper shows that a crude mechanical model of coherently rotating vortices can account quantitatively not only for spin, but also for the wavefunction itself. The implications of this are discussed in this paper. [ABSTRACT FROM AUTHOR]

The quantum relationship m0c2 = ħ\ω0\ may be regarded as the equivalence between two expressions for the rest energy of the particle, if ω0 is considered as the spin angular velocity of the particle in its rest frame. The invariance of the relativistic space-time interval ds2 = c2dt2 - dr2 to such a spin motion (space isotropy) leads to the spin momentum Sz = ħ /2 for all structureless particles irrespective of their mass values. The inertia is an intrinsic property due to the spin motion of the particles. The signs of the mass values occurring in the solutions of the Dirac equation might be related to the orientation of the spin motion, as suggested by the fundamental relationship ±m0c2 = ±ħ\ω0\. In addition, it deals with the electron, and more specifically with two key properties: its complex wavefunction and its intrinsic? spin. In the standard interpretation, there is no clear real-space picture of what is oscillating in the wave, or what is rotating in the spin. Indeed, it is generally believed that no simple model of rotation can account for the spin of the electron. On the contrary, the present paper shows that a crude mechanical model of coherently rotating vortices can account quantitatively not only for spin, but also for the wavefunction itself The implications of this are discussed in this paper. [ABSTRACT FROM AUTHOR]

A problem related to the operation of industrial machines has been the identification of the mechanical condition in exploitation, via dynamic performance variables which affect the nominal behavior of machine tasks. This paper proposes a set of algorithms focused on identifying of the mechanical condition industrial machines. Therefore, a tool to the maintenance based on the condition is developed; the methodology proposed is focused on the identification of the mechanical condition through recording dynamic variables by applying vibro-estimators techniques via Single Value Decomposition (SVD) method, and development of experimental tests on industrial machines. The work has been conducted on two sets of measurements from a real case study on two identical machines, one machine having nominal operation behavior, and the other machine having a dynamic problem. [ABSTRACT FROM AUTHOR]

This paper presents two numerical models for the evaluation of the distribution of stresses in corrugated sheets of fibre cement subjected to uplift load. The numerical simulations, in this case, were made from three-dimensional models using the software SAP2000Nonlinear, version 7:42, which has as base the finite elements method (MEF). Corrugated sheets with thickness of 5 mm considering two different spans, i.e., 1100 mm and 1530 mm were evaluated. The sheets had the 2nd and 5th high waves fixed. The load of suction applied on the sheets was 10 kN/m2, and it was verified that the stresses on the sheets are distributed heterogeneously in a more complex pattern than for the bending stresses for vertical loads. The sheets suffer bending in transverse and longitudinal directions for the suction load applied, and the attachment points of sheets present concentration of stresses. The numerical results of the stresses showed good agreement with the results obtained from other researchers and these results can be used to predict the behavior of corrugated sheets of fibre cement subjected to wind load suction. [ABSTRACT FROM AUTHOR]

This paper presents the design and implementation of a novel technique for the recognition of four hand motions for real time response (flexion (FL), extension (EX), opening (OP) and closure (CL)) from electromyographic (EMG) signals generated from two forearm muscles: palmaris longus and extensor digitorum. The development of the work had two main stages: the low cost hardware for acquisition and conditioning of the EMG analog signals and the processing system for the identification and classification of the movement performed for real time response; the entire system was integrated in a hardware-software application using MATLAB and processing techniques for the discriminant analysis were performed. Three methods were evaluated for pattern recognition getting 98% recognition rates with the method proposed which had the best performance. [ABSTRACT FROM AUTHOR]

This article describes two new methodologies for optimal distribution system planning considering automatic reclosers to improve reliability indices. The first methodology proposed in this paper employs a two-stage cascade strategy to solve the problem. In the first stage a mono-objective Tabu Search (TS) algorithm is used to find the optimal distribution system topology. The installation cost of new elements, increasing capacity on existing elements and operational costs associated with technical losses are considered. In the second stage a Non-Dominated Sorting Genetic Algorithm known as NSGA II is employed, considering the optimal distribution system topology found by the first stage, and thus, solving the problem of optimal location of automatic reclosers in distribution systems. The non-supplied energy level of the network and installation cost of reclosers are considered as objective functions; and the min-max criterion to select a point on the optimal Pareto front is used. In the second methodology, a master-slave based optimization algorithm is used to find the best network topology including the associated to automatic reclosers. Master algorithm is a TS algorithm which is responsible to direct the optimization process through solution space, whereby, for each neighbor generated, the slave algorithm NSGA II is applied and min-max criterion is used to determine a configuration of reclosers for actual network topology. The proposed methodologies are applied on three-phase version of IEEE 34 nodes test feeder, with high quality results. [ABSTRACT FROM AUTHOR]

In the actual context in which commercial industries need to achieve greater competitiveness through their processes, efficiency is required in the management of electricity. Commercial buildings need solutions that are adequate to their environment and that would mean economic benefits. Given the case in which a commercial building self-generates electricity from renewable energy sources (RES), methods are required for allowing evaluation of alternative sources for generation, taking into account both the RES and methods characteristic uncertainties, which are involved in the process of technology selection. This paper proposes a hybrid method composed by technics of Analytic Hierarchy Process (AHP), the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), the Theory Real Option Analysis (ROA), the Monte Carlo Simulation (MCS), and the Binomial Method (BM), to select the most adequate technologies for electricity self-generation in Shopping Centers (SCs); it takes into account economic, environmental, technological and technical criteria, within the Colombian regulatory framework. The case study was based on real data for SCs in three different Colombian cities with different meteorological conditions. It was demonstrated that taken into account the real options, the photovoltaic technologies are viable projects to be implemented in the commercial sector. The study is a conceptual contribution and it proposes a methodology for improving the understanding of the complex process of decision making with its application in the evaluation of RES technologies, considering the incentives and the implicit real options in the regulatory framework of a region or a country. [ABSTRACT FROM AUTHOR]

In this paper the ultrasonic signal is used for early failure detection in tapered roller bearings. The faults studied were localized in outer race, inner race, cage and the rolling elements. The implemented failures emulate three distinct levels of severity. The ultrasonic signal analysis is performed using time domain parameters i.e. kurtosis and RMS, and in the frequency domain using the power spectral density obtained by the Welch periodogram. Although none of the studied parameter was able to extract the fault location, the RMS parameter presents the best performance as a feature to monitor allowing to identify faulty conditions and evaluate qualitatively the severity of the fault. [ABSTRACT FROM AUTHOR]

The current development of technologies has boosted the use of telecommunication services. This fact brings an increase in the volumes of data generated in telecommunication companies. Such data need to be processed in order to detect potential intruders or fraud. The rule evaluation techniques are widely used in these application contexts due to their high effectiveness over known attacks. The incorporation of an automatic rule generator allows it to obtain rules in large volumes of data, for assisting information analysts; thus, the accuracy of intrusion detection is increased. In this paper, an automatic rule generation method is presented, including a strategy based on processing the patterns extracted from a training set and building classification rules. Finally, our proposal is evaluated and compared regarding other classifiers, achieving good results. [ABSTRACT FROM AUTHOR]

This paper analyzes the performance of three different semi-active control algorithms used to calculate and manage the optimal damping forces generated by a pair of magnetorheological (MR) dampers installed in a two-story building. The semi-active algorithms used are the linear quadratic regulator (LQR) associated with the clipped optimal algorithm, an algorithm based on a prediction model and a dynamic inverse model using nonlinear autoregressive exogenous (NARX)-type artificial neural networks, and a decision-making algorithm based on fuzzy logic. Additionally, the performances of the proposed semi-active algorithms are compared to those of passively used control devices. The results show response value reductions exceeding 50% for all the semi-active control strategies, which considerably outperformed the passive control. The three control strategies are thus confirmed as interesting tools with potential applications as MR damper administrators. [ABSTRACT FROM AUTHOR]

The scenario generated by the increasing role of lead logistics providers, as well as a possible increased competition caused by government grant for some major Brazilian international airports, is demanding from those involved in the air cargo supply chain actions that promote improvements in services in order to make them more efficient. Influenced by this concern, this paper proposes a Three-Phase Method of multicriteria decision aid for the major services of the Brazilian international air cargo logistics chain. Using the foundations of the proposed method, the Phase 1 and Phase 2 are elaborated. In Phase 1, problem consolidation was performed and also the two main logistics strategic decisions were identified. In Phase 2, structuring multicriteria model is elaborated, identifying the aspects of such as criteria and sub-criteria for strategic decision of cargo only airlines, when selecting Brazilian international airports. In this Phase is also constructed, for a specific case-study, the hierarchical structure of the problem is also constructed. [ABSTRACT FROM AUTHOR]

This paper presenting as contribution a model for the evaluation, control, and improvement of airport safety by analyzing different operational events. This model is based on multicriteria methods, in particular, the entropy and TOPSIS methods. It allows to operationalize the evaluation of the airport ramp safety performance in contexts of scarce information about the weights of each criterion, and where the absence of personal judgments in the weighting process is considered important. Operational events were used to develop the criteria. In addition, an application was conducted and the data from airport ramp safety events were used to identify trends, diagnose problems, support the planning of actions, and provide a basis for allocating resources for prevention of catastrophic accidents and improvement of safety. This application was used to validate the model. It was concluded that the airport ramp safety did not maintain a trend of continuous improvement and the proposed model allowed the identification of trends, of criteria with low performance, and the realization of recommendations for improvinge airport safety. [ABSTRACT FROM AUTHOR]

The analyses for overcoming problems arising in basic grid substation buses and equipment are of essential importance to the Brazilian electric sector in view of the constant expansion of this system. These analyses are not simple tasks because they involve an evaluation of the impacts caused by installations arising from new connections and because they always include various studies. This paper presents examples of necessary investigations into the causes of the rated characteristic violations of basic grid installation components. An overview of the proposed electrical system that will be evaluated in conjunction with a new thermal generator plant connection to an existing system substation system is presented. [ABSTRACT FROM AUTHOR]

Investors need reliable information for decision-making, so it is important to measure the quality of public information disclosed by quoted companies. This paper advances in the measurement of disclosed information using the multiple correspondence analysis methodology to reduce the number of traditionally used variables, resulting in three variables: i) disclosure of accounting policies and criteria, ii) disclosure of financial information and iii) disclosure of the board assessment. Using three these dimensions, we characterize and classify the analyzed companies according to their information disclosure. [ABSTRACT FROM AUTHOR]

This paper presents a column generation algorithm for solving combined vehicle and inventory problems. This problem is based on the idea of coordinating customer inventory levels through a minimum routing cost. This is a combinatory decision problem since vehicle routing and inventory problems, are combined. Using the column generation method, we can iteratively generate interesting routes to the system, based on their dual costs, this is routes that will improve the quality of the objective function because its reduced costs are negatives. The initial mixed integer problem has to be relaxed for getting its reduced costs. The sub problem is defined as the shortest path problem that returns a set of desirable routes. Finally, when the set of desirable routes is obtained, the mixed integer model should select a set of routes that fulfill both minimum shipping costs and the constraints of the system. [ABSTRACT FROM AUTHOR]

For industrial automation it is often necessary to sort a large number of objects in a certain order for a subsequent step of process. Today, this is made by combining several pick and place robots, which move the objects to their desired destination one at a time. For a large number of objects per unit of time, this solution may become impractical because the individual robots may interfere with each other and the accelerations caused may be too high. This paper describes the principle of operation of a vibratory manipulator that produces impulsion force vector fields generated by longitudinal and transverse oscillations about a horizontal plane, which allow both movements of transport and orientation of parts. The manipulator has a rigid moving plate on which the object to move is placed. Then, forces on the moving plate are induced by longitudinal mechanical vibrations with asymmetric velocity profiles. Eight electromagnetic actuators that, in conjunction with flexible couplings, transmit longitudinal oscillations to the moving plate generate these velocity profiles. The amplitude of motion for each actuator is programmed by the user depending on the trajectory that the piece shall follow. [ABSTRACT FROM AUTHOR]

Water retention curve (WRC) is a nonlinear function that describes the relationship between the matric suction (ψ) and water content (θ) of a porous material evaluated under unsaturated conditions. WRC contains fundamental information about hydro-mechanical behavior of unsaturated porous materials of different composition. In this context, this paper presents the laboratory results and procedures used to determine the WRC of a soil-cement composite material used in road pavement construction. With this purpose, water content and matric suction measurements in a soil-cement composite with 3.5% of Portland cement by using pressure cells were developed. Fitting values of the WRC were calculated according to the theoretical four-parameter van Genuchten model. Hence, the best fit parameters of the van Genuchten water retention curve were estimated using a nonlinear fitting approach based in minimizing the sum of squared-error in nonlinear functions. Results show that the water retention curve and its parameters according to the van Genuchten model determined in this study can be used as reference values of the unsaturated parameters of soil-cement composite material used in road pavement construction. Moreover, soil-cement water retention curve shown in this study corresponds to one of the first results published in the literature on this composite material. [ABSTRACT FROM AUTHOR]

Nuclear quadrupole resonance (NQR) is a spectroscopic technique that can detect explosives of high chemical specificity and therefore it is very suitable for the landmine detection problem. There are several factors affecting the relation of noise signal ratio with NQR: molecular dynamics of relaxation, interference signals, thermal noise, explosive amount, distance, temperature and the design of the detecting system. Literature has searched ways for solving one or more of these factors, but since not all the work has been focused on landmine detection, many have only been tested in simulation or with data obtained under controlled laboratory conditions, where the detection is not remote (there is no separation between the sample and the detection system). This paper makes a review of the state of art in NQR, analyzing its relevance to the landmine detection problem and concluding about unsolved problems that could be the focus of future research. [ABSTRACT FROM AUTHOR]

The efficiency of combustion in furnaces is the measure of heat released in the flame absorbed by the fluid to be heated and is considered one of the most important variables when conducting studies on processes that occur in continuous process industries. The furnace efficiency is calculated using various mathematical models proposed in the literature; these models vary in complexity depending on the analyzed variables. The models I and II are based on the amount of energy absorbed by the furnace using the heating value, the model III contains variables such as air excess, stack gas temperature and adiabatic flame temperature, meanwhile the model IV contains heating losses in furnace's wall (2%), the stack gas temperature and excess air. In this paper was used computer simulation to evaluate fuel gas mixtures with Lower Heating Values (LHV) between 800 to 2500 Btu/ft3, and they were compared with natural gas and data process; the results show that the combustion characteristics might change by varying the fuel composition. It was also found decreased combustion efficiency due to high hydrogen concentration; on the other hand the adiabatic flame temperature was increased in function of gas composition. Model IV presented in this research allowed evaluating combustion process efficiency using only two variables: stack gas temperature and the excess air. [ABSTRACT FROM AUTHOR]

By analyzing futures contracts, this paper examines the volatility of West Texas Intermediate (WTI) crude oil and refined product prices (short, medium and long-term) before and after the financial crisis of 2008. Daily historical data from January 2000 to June 2008 (pre-crisis period) and from May, 2009 to October, 2012 (post-crisis period) were evaluated. AR-GARCH models were adjusted to these series, with the purpose of estimating volatilities and the persistence of shocks. After the crisis, the short-term volatility of the three commodities diminished. The persistence of shocks increased for most contracts after the 2008 crisis. The relevance of this type of analysis is related to the importance of volatility, not only to the agents who negotiate the physical products but also to the traders and their daily positions on exchanges. [ABSTRACT FROM AUTHOR]

This article shows the results of applying social network analysis techniques to explore the antecedents in the formation of collaborative learning networks in Chile. Immersed in learning analytics, the paper indicates a set of individual variables of students that explain the relationship structure between them for the purpose of collaborating in the study. In particular, the study used a Multiple Regression Quadratic Assignment Procedure to analyze a network of students belonging to a Chilean university. The results support the existence of three antecedents in the formation of a network to collaborate in the learning: homophily, closeness in the academic performance and looseness in the happiness level. [ABSTRACT FROM AUTHOR]

This paper presents a teletraffic study that evaluates the benefits of a passive optical access network, fix/mobile, by multiplexing wavelength division (WDM-PON) in which it is appreciated the impact of including extra wavelengths channels for the transmission of multicast services versus the multicast transport service using replicated unicast connections. The conclusion is that under heavy bulk-data traffic, the nominal data rate and tolerated efficiency are defined by the maximum number of out-of-profile users permitted for every multicast solution. Specifically, for the high values of efficiency the channels of extra wavelength avoid the need of multicast wavelengths used only when there is a fraction (significantly small) of out-of-profile users (5%). [ABSTRACT FROM AUTHOR]

This paper describes a first approach of 5S impact on the study factors of quality, productivity, industrial security and organizational climate in the manufacturing area of Small and Medium Enterprises (SMEs) in Colombia, through a case study carried out in a small company located in Bogotá, in order to evaluate whether the 5S methodology could be considered as an effective tool to improve manufacturing companies. A visual diagnosis was chosen to identify the area that presented the greater amount of clutter and dirt. Once the location was identified, surveys, performance measures and a risk landscape were performed, focusing on the study factors, in order to understand the initial situation of the area. Subsequently, the implementation of 5S was carried out and then three measurements were taken to monitor the performance of the study factors, so as to know if they followed a trend during the measuring period. The results show the existence of a positive relationship between the study factors and the implementation of the 5S methodology, since an increase of productivity and quality was evidenced, based on the performance measures as well as an improvement of the organizational climate and a decrease of the risks identified in the workshop. [ABSTRACT FROM AUTHOR]

The KAOS (Knowledge Acquisition in Automated Specification) goals diagram is one of the most important diagrams during software requirements elicitation, that is to say, the first phase of a program's life cycle, since it helps stakeholders (users) to understand the importance of future software. In the studies in order to identify the traceability that should exist between natural language and the goals that have been identified to avoid inaccuracies between them was not possible. This paper presents a method for extracting and classifying goals in KAOS approach through the processing of textual requirements in Spanish. In this method, the phrases found in a text are broken down and a morphological and syntactical analysis is carried out for each phrase, using the classification of Spanish verbs as reference. Furthermore, morphosyntactic structures are defined which allow the goals to be typified and classified, based on the following types: (i) Maintain; (ii) Achieve; (iii) Cease and (iv) Avoid. This classification aims to list all of the goals and to represent them according to the KAOS goal model. This method will serve as a starting point for identifying the other components that make up the KAOS goal diagram and the semiautomatic rendering of said diagram. [ABSTRACT FROM AUTHOR]

Memes have recently come into vogue in the context of 'viral' transmission of basic information units in online social networks. However, from their original general definition in a sociological context, there is still much work to be done from an information technology viewpoint. This includes such issues as how to process memes from real text corpus, formal definitions for knowledge representation, meme refinement and selection. In order to address these issues, in this paper we adapt definitions from the semantic network and information retrieval fields to extract memes as semantic networks from free text documents, and then we present some examples in the context of a simple online forum. [ABSTRACT FROM AUTHOR]