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Cartaxo B.,IFPE | Cartaxo B.,Federal University of Pernambuco | Pinto G.,IFPA | Ribeiro D.,Federal University of Pernambuco | And 4 more authors.
IEEE International Working Conference on Mining Software Repositories | Year: 2017

Questions and Answers (Q&A) websites maintain a long history of needs, problems, and challenges that software developers face. In contrast to Q&A websites, which are strongly tied to practitioners' needs, there are systematic reviews (SRs), which, according to recent studies, lack a connection with software engineering practice. In this paper, we investigate this claim by assessing to what extent systematic reviews help to solve questions posted on Q&A websites. To achieve this goal, we propose and evaluate a coverage method. We applied this method to a set of more than 600 questions related to agile software development. Results suggest that 12% of the related questions were covered. When considering specific agile methods, the majority of them have coverage below 50% or were not covered at all. We also identified 27 recurrent questions. © 2017 IEEE.


Kamei F.,IFAL | Pinto G.,Federal University of Pará | Cartaxo B.,Federal University of Pernambuco | Vasconcelos A.,Federal University of Pernambuco
ACM International Conference Proceeding Series | Year: 2017

Context: For more than 15 years, Agile Software Development (ASD) has been used to improve software development, process, and quality. However, there are scenarios where the effectiveness of these methods and practices has not been rigorously evaluated. Objective: Understand the benefits and limitations related to these methods and practices in a particular context: two software companies based on Pernambuco's Technology Park, Brazil. Method: In this paper, we conducted 22 semi-structured interviews to understand the benefits and limitations of ASD in an industrial context. The data were extracted using open coding and analyzed through qualitative techniques. Results: Our preliminary analysis identified a core of 28 benefits and 20 limitations with the usage of ASD. As for benefits, we found that facilitates project monitoring and tracking as well as the interaction and collaboration. As for limitations, we found that it difficulty working with user stories and to work with large teams. Conclusion: This study serves as a practical guide for software companies interested in adopting and improving the use of ASD. © 2017 ACM.


Gomes Silva M.J.,IFAL | Silva Araujo C.,Federal University of Paraiba | Marques Bezerra S.T.,Federal University of Pernambuco | Rocha Souto C.,Federal University of Paraiba | And 2 more authors.
IEEE Latin America Transactions | Year: 2015

This paper presents the project of an adaptive control system to modeling and controlling, in real time, a water distribution system. The controllers act in determining the turning speed of the motor/pump set and in the opening angle of control valves. An experimental workbench was set aiming at modeling and identifying parametrically a hydraulic network. The control system is a Generalized Minimum Variance self-tuning (GMV), whose parameters where real-time estimated by the recursive least squares (MQR) method according to the imposed inputs to the converter and the valves. The GMV aims at the pressure control in measuring points, which provided the reduction of energy and water in the workbench. Experimental results show the performance of adaptive control system and its ability to control the water distribution process. © 2003-2012 IEEE.


Porto M.L.A.,IFAL | Puiatti M.,Federal University of Viçosa | Fontes P.C.R.,Federal University of Viçosa | Cecon P.R.,Federal University of Viçosa | Alves J.C.,IFAL
Horticultura Brasileira | Year: 2014

The employment of SPAD index for N status diagnosis of crops has been largely studied in recent years. Our objective was to evaluate the employment of SPAD index for nitrogen status diagnosis of Japanese cucumber plants (Taisho hybrid) under protected cultivation. The randomized block design was used, arranged in a 2×5 factorial design, with two nitrogen sources (ammonium sulfate and ammonium nitrate) and five nitrogen doses (0; 75; 150; 300 and 600 kg ha-1), with four replications. At the early flowering stage, total chlorophyll concentration, SPAD index and total nitrogen concentration in the fourth fully expanded leaf from the apex of Japanese cucumber plants were evaluated. No significant effects of nitrogen sources and of the interaction between nitrogen sources and nitrogen doses were found under the evaluated characteristics. However, total chlorophyll concentration, SPAD index and total nitrogen concentration in Japanese cucumber leaves increased following a quadratic model depending on the nitrogen doses. The estimated critical levels of total chlorophyll concentration, SPAD index and total nitrogen concentration on Japanese cucumber (Taisho hybrid) leaves responsible for the highest fruit yield were 6.01 mg g-1 of fresh matter, 52.33 units and 4.78 dag kg-1 of dry matter, respectively. Significant linear and positive correlation between the evaluated characteristics were observed. The SPAD index can be used for nitrogen status diagnosis of Japanese cucumber plants.


Porto M.L.A.,IFAL | Puiatti M.,Federal University of Viçosa | Fontes P.C.R.,Federal University of Viçosa | Cecon P.R.,Federal University of Viçosa | Alves J.C.,IFAL
Horticultura Brasileira | Year: 2014

The importance of hybrid winter squash ("Tetsukabuto" type) is rising in Brazil, especially in Minas Gerais state, but few studies have been carried out in relation to fertilization. We evaluated yield and nitrate accumulation in fruits of hybrid winter squash ("Tetsukabuto" type) depending on the nitrogen fertilization in Viçosa, Minas Gerais state, Brazil. The randomized block experimental design was used, arranged in a 2×5 factorial design, with two nitrogen sources (ammonium sulphate and ammonium nitrate) and five nitrogen doses (0; 50; 100; 200 and 400 kg ha-1), and four replications. The number of fruits per plant, average fruit mass, fruit yield and nitrate accumulation in the fruits were evaluated. No significant effects of nitrogen sources and of the interaction between nitrogen sources and nitrogen doses was found on the productive characteristics of the hybrid winter squash, but these characteristics were increased depending on the N doses applied. The highest number of fruits/plant (6.9 units), highest average fruit mass (1.76 kg/fruit) and highest fruit yield (17.16 t ha-1) were obtained in the doses 339, 217 and 260 kg -1 of N, respectively. The rates of N for maximum economic efficiency were 251 and 238 kg ha-1, resulting in fruit yields of 17.15 and 17.07 t ha-1, for the ammonium sulfate and ammonium nitrate, respectively. Nitrate accumulation in fruits employing N doses in the form of ammonium sulfate was not verified. However, the nitrate content in the fruits presented lineal increment depending on the N doses in the form of ammonium nitrate. At the highest N rate, the nitrate content in the fruit fresh matter was 406 mg kg-1. However, this nitrate content value does not represent risk for human health.


Porto M.L.A.,Federal University of Viçosa | Alves J.C.,IFAL | de Souza A.P.,Federal University of Paraiba | Araujo R.C.,Federal University of Paraiba | And 2 more authors.
Horticultura Brasileira | Year: 2012

Lettuce production in hydroponic system presents growing expansion in Brazil, but still there are problems of quality and risk of nitrate accumulation. This work was carried out to evaluate the lettuce production and nitrate accumulation in hydroponic system depending on the increasing levels of nitrogen in the nutrient solution. The experiment was conducted in greenhouse of the Universidade Federal da Paraíba, Brazil. The lettuce plants were grown in nutrient solution containing increasing levels of N (11, 13, 15, 17, 19 and 21 mmol L-1) during a 25-day period. An entirely randomized design with four replications was used. Plant total yield (PTT), plant commercial yield (PCM) and nitrate contents in the fresh matter of roots, stems and leaves of the lettuce were evaluated. There were no significant effects of increasing levels of N in nutrient solution on PTT and PCM, average values of 357.3 and 352.5 g/plant being observed, respectively. The increased levels of N in nutrient solution increased linearly nitrate content on all lettuce parts. The nitrate content reached 659, 623 and 615 mg/kg in the fresh matter of roots, stems and leaves, respectively, at the highest N level. Nevertheless, the maximum nitrate content observed in leaves was far below the risk level for human health.


Argolo C.,IFAL | Otaviano H.,IFAL | Gleria I.,Federal University of Alagoas | Arashiro E.,Federal University of Ouro Preto | Tome T.,University of Sao Paulo
International Journal of Bifurcation and Chaos | Year: 2010

We investigate the critical behavior of a stochastic lattice model describing a predatorprey system. By means of Monte Carlo procedure we simulate the model defined on a regular square lattice and determine the threshold of species coexistence, that is, the critical phase boundaries related to the transition between an active state, where both species coexist and an absorbing state where one of the species is extinct. A finite size scaling analysis is employed to determine the order parameter, order parameter fluctuations, correlation length and the critical exponents. Our numerical results for the critical exponents agree with those of the directed percolation universality class. We also check the validity of the hyperscaling relation and present the data collapse curves. © 2010 World Scientific Publishing Company.


Oliveira L.C.,Federal University of Campina Grande | Melcher E.U.K.,Federal University of Campina Grande | Melcher E.U.K.,Center for Strategic Technologies | Thirstrup C.,Coloplast | And 3 more authors.
2012 IEEE I2MTC - International Instrumentation and Measurement Technology Conference, Proceedings | Year: 2012

This paper presents a surface plasmon resonance (SPR) sensor system based on a polymer prism chip. The device allows operation in both, the angular (AIM) and wavelength (WIM) interrogation modes. The basic mathematical formulation for both operating modes is discussed. Experimental sensogrammes obtained for both modes with the same polymer prism chip, are presented and compared. The results illustrate the feasibility of the proposed solution. © 2012 IEEE.


Souza-Junior M.,IFAL | Queiroz L.,IFAL | Correia-Neto J.,Federal Rural University of Pernambuco | Vilar G.,Federal Rural University of Pernambuco
Advances in Intelligent Systems and Computing | Year: 2016

The concept of applications (apps) as medical devices emerges as an important one in the field of mobile health (m-health). Within this field, apps have been used as tools that can drastically change the quality of healthcare on a global scale, as well as radically alter the reach of medical investigation. The use of gamification techniques to inspire the experience of app users has also stimulated the field of m-health, using the mechanics of games to improve the thought processes of app users. The article evaluates four m-health apps from the standpoint of the gamification of their functionalities. To this end, we have adopted the analytical framework of Werback and Hunter and used a six-step system. Our results empirically confirm some of the evidence found in the current literature; that is, the majority of apps that use gamification elements aim to achieve publicity as a secondary objective. © Springer International Publishing Switzerland 2016.

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