• 3D semi-analytical solution of hygro-thermo-mechanical multilayered doubly-curved shells

      Monge, J. C.; Mantari, J. L.; Arciniega, R. A. (Elsevier Ltd, 2022-04-01)
      In this paper, a three-dimensional bending solution of doubly-curved shells subjected to mechanical, thermal and hygrothermal load is studied. Through-the-thickness temperature of the shell is modeled by Fourier's heat conduction equation. Fick's moisture diffusion law equation is used to determine the hygro-thermal profile through-the-thickness. The partial differential equations are solved by using the Navier closed form summations which are valid only for shells with constant radii of curvature among the midsurface and with simply supported boundary conditions on its shell's edges. The shell governing equations are solved by discretizing the thickness profile via Legendre's grid distribution and by using the Differential Quadrature Method (DQM). The Layerwise capabilities of the method is guaranteed by imposing the inter-laminar continuity of out-of-the-plane stresses, displacements, temperature and hygrothermal load thickness profile. The zero-stress condition for the transverse shear stresses is imposed due to the fact that no mechanical loads are applied in those directions. Results for cylindrical, spherical panels and rectangular plates are presented. Comparisons are made with Layerwise and three-dimensional solutions available in literature. The results have strong accuracy and a benchmark problem is delivered.
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    • 5S hybrid management model for increasing productivity in a textile company in Lima

      Neyra, Juanirene; Muñoz, José; Eyzaguirre, Juan; Raymundo, Carlos (Springer Verlag, 2020-01-01)
      In general, lean strategies in the textile sector are applied in production to improve productivity, reduce production time, and reduce errors, among other aspects. However, there are also documented studies, which are not common in the literature that uses these strategies to improve storage operations. This study shows the implementation of the Lean 5S Hybrid tool in the warehouse of a textile company based in Lima. The objective of the implementation was to improve productivity in the warehouse, as there were high response times when searching for materials, which reduced production time, warehouse redistribution, better using available space, and being able to strategically locate main materials. The results revealed an increase in warehouse productivity 3.95 times the initial one, an Inventory Record Accuracy of 98.17%, a decrease in the requirement search time by 66.12% (from 25 to 8 min), and stock rotation of 6.22 times.
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    • 6TOC model for small wood furniture companies to increase machining productivity in Villa El Salvador industrial cluster

      Gutierrez, Leonel; Laredo, Jesus; Sotelo, Fernando; Raymundo, Carlos (Springer Verlag, 2020-01-01)
      This research article focuses on the application of the main engineering tools in the wood furniture manufacturing sector. It uses as an information source furniture companies of the industrial park of Villa El Salvador. Its objective is to implement 6TOC methodology based on LEAN philosophy, Six Sigma and restrictions theory, focusing on improvements to the bottleneck. Defines the product design as an ideal input for the planning and development of activities. Start to know the work environment: stations and functions, machines and tools, plant layout and ergonomics in order to increase productivity. Application of tools level operations for planning, control and execution of production. Resulted in the GDP in the year 2017 increased by 2.2%. However, the manufacturing sector of goods decreased by 5.5%, that is, it impairs GDP growth, since the wood and furniture industry, which had an aggregate gross manufacturing value of −19.9%.
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    • A 12-month clinical trial examining the effects of a surface sealant on Class I composite resin restorations.

      Nahsan, Flavia Pardo Salata; Wang, Linda; Modena, Karin Silva; Francisconi Dos Rios, Luciana Fàvaro; Silva, Luciana Mendonça da; Calabria, Marcela Pagani; Casas-Apayco, Leslie; Mondelli, Rafael Francisco Lia (Chicago, Academy of General Dentistry, 2016-03)
      A split-mouth, double-blind trial evaluated the effects of a surface sealant on the clinical performance of Class I composite resin restorations. In 16 patients, 27 pairs of maxillary and mandibular molars or premolars with Class I carious lesions or unsatisfactory restorations were restored with composite resin. For each pair, 1 surface was sealed with surface sealant. Clinical evaluations of marginal integrity, marginal discoloration, anatomical form, and secondary caries were performed by 2 experienced operators using modified US Public Health Service criteria 1-2 weeks and 6 and 12 months after treatment. Data were analyzed with the McNemar test (P < 0.05). After 6 months, only 1 (4%) sealed restoration presented a Bravo rating for marginal integrity. After 12 months, the Bravo ratings for marginal integrity were 2 (7%) for sealed restorations and 1 (4%) for nonsealed restorations. Restorations received a score of Alfa for all other parameters at all time periods. There were no statistically significant differences within or between the sealed and nonsealed groups (P = 1.0). The use of a surface sealant did not improve the clinical performance of posterior composite resin Class I restorations.
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    • A biometric method based on the matching of dilated and skeletonized IR images of the veins map of the dorsum of the hand

      Universidad Peruana de Ciencias Aplicadas (UPC) (IEEE, 2015-06-02)
      This work proposes a biometric identification system that works together with a palm vein reader sensor and a hand-clenching support, designed to perform the capture the back of the hand. Several processing steps were performed: extraction of the region of interest, binarization, dilation, noise filtering, skeletonization, as well as extraction and verification of patterns based on the measurment of coincidence of vertical and horizontal displacements of skeletonized and dilated images. The proposed method achieved the following results: processing time post capture of 1.8 seconds, FRR of 0.47% and FAR of 0,00%, with a referential database of 50 people from a total of 1500 random captures.
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    • A comment on “Body image and paranoia”

      Jeri-Yabar, Antoine; Marin-Leiva, Javiera; Tejada, Romina A. (Elsevier Ireland Ltd, 2018-01)
      Cartas al Editor
    • A community randomised controlled trial evaluating a home-based environmental intervention package of improved stoves, solar water disinfection and kitchen sinks in rural Peru: Rationale, trial design and baseline findings

      Hartinger, S.M.; Lanata, Claudio F.; Hattendorf, J.; Gil, I.; Verastegui, H.; Ochoa, T.; Mäusezahl, D. (Elsevier B.V., 2015-03-24)
      Introduction: Pneumonia and diarrhoea are leading causes of death in children. There is a need to develop effective interventions. Objective: We present the design and baseline findings of a community-randomised controlled trial in rural Peru to evaluate the health impact of an Integrated Home-based Intervention Package in children aged 6 to 35 months. Methods: We randomised 51 communities. The intervention was developed through a community-participatory approach prior to the trial. They comprised the construction of improved stoves and kitchen sinks, the promotion of hand washing, and solar drinking water disinfection (SODIS). To reduce the potential impact of non-blinding bias, a psychomotor stimulation intervention was implemented in the control arm. The baseline survey included anthropometric and socio-economic characteristics. In a sub-sample we determined the level of faecal contamination of drinking water, hands and kitchen utensils and the prevalence of diarrhoegenic Escherichia coli in stool specimen. Results: We enrolled 534 children. At baseline all households used open fires and 77% had access to piped water supplies. E. coli was found in drinking water in 68% and 64% of the intervention and control households. Diarrhoegenic E. coli strains were isolated from 45/139 stool samples. The proportion of stunted children was 54%. Conclusions: Randomization resulted in comparable study arms. Recently, several critical reviews raised major concerns on the reliability of open health intervention trials, because of uncertain sustainability and non-blinding bias. In this regard, the presented trial featuring objective outcome measures, a simultaneous intervention in the control communities and a 12- month follow up period will provide valuable evidence.
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    • A Computational Comparative Analysis Between Nvidia Jetson Nano and Raspberry Pi CM4 for the Classification of White Asparagus with SVM

      Ruiz, Edgar; Ortiz, Manuel; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      The following study proposes to analyze and compare the computational response provided by the Single Board Computers (SBC) Raspberry Pi CM4 and Nvidia Jetson Nano because those are important elements in machine learning applications and implementation of automated systems. Both were chosen due to their similar specifications to achieve a fair comparison. For the development of this research, an algorithm was implemented with a Support Vector Machine to be able to compare the performance in real-time of both computers based on performance metrics such as execution time, algorithm accuracy, CPU performance, and temperature. To validate results, there is a database of 2186 white asparagus images, which were classified based on attributes such as length, curvature, diameter, and purple hue. These attributes are established by the Peruvian Asparagus and Vegetable Institute (IPEH) in the Peruvian Technical Standard to ensure the quality of fresh asparagus for export. The algorithm has been designed to classify asparagus according to this technical standard.
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    • A Cost Analysis of Gyrase A Testing and Targeted Ciprofloxacin Therapy Versus Recommended 2-Drug Therapy for Neisseria gonorrhoeae Infection

      Allan-Blitz, Lao-Tzu; Hemarajata, Peera; Humphries, Romney M.; Wynn, Adriane; Segura, Eddy R.; Klausner, Jeffrey D. (Lippincott Williams and Wilkins, 2018-02)
      From the *Division of Infectious Diseases, Department of Medicine, †Department of Laboratory Medicine, David Geffen School of Medicine, Department of Medicine, ‡Fielding School of Public Health, University of California Los Angeles, Los Angeles, CA; §Escuela de Medicina, Universidad Peruana de Ciencias Aplicadas, Lima, Peru; and ¶Division of Infectious Diseases, Department of Medicine, University of California Los Angeles, Los Angeles, CA Conflict of Interest and Sources of Funding: None declared. This research was supported by the United States National Institutes of Health grants R21AI117256 and R21AI109005 as well as the South American Program in HIV Prevention Research NIH/NIMH R25MH087222. Correspondence: Lao-Tzu Allan-Blitz, MD Candidate, 2018, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles, CA 90095. E‐mail: [email protected] Received for publication February 21, 2017, and accepted July 30, 2017. DOI: 10.1097/OLQ.0000000000000698
    • A critical appraisal on the association and effects of magnesium and bone density on physical performance in elderly women.

      Unocc, Carla P; Valdez, Laura I; Segura, Eddy R.; [email protected] (American Society for Nutrition, 2015-04)
      Cartas al editor
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    • A decision tree–based classifier to provide nutritional plans recommendations

      Aguilar-Loja, Omar; Dioses-Ojeda, Luis; Armas-Aguirre, Jimmy; Gonzalez, Paola A. (IEEE Computer Society, 2022-01-01)
      The use of machine learning algorithms in the field of nutritional health is a topic that has been developed in recent years for the early diagnosis of diseases or the recommendation of better nutritional habits. People with poor diets are more prone to chronic diseases and, in the long term, this can lead to dead. This study proposes a model for the recommendation of nutritional plans using the decision tree technique considering the patient data, in complement with the BMI (Body Mass Index) and BMR (Basal Metabolic Rate) to evaluate and recommend the best nutritional plan for the patient. The algorithm used in the model was trained with a dataset of meal plan data assigned by specialists which were obtained from the Peruvian food composition table, and the data from the diets that were assigned and collected from the nutrition area of the Hospital Marino Molina Sccipa in Lima, Peru. Preliminary results of the experiment with the proposed algorithm show an accuracy of 78.95% allowing to provide accurate recommendations from a considerable amount of historical data. In a matter of seconds, these results were obtained using Scikit learn library. Finally, the accuracy of the algorithm has been proven, generating the necessary knowledge so that it can be used to create appropriate nutritional plans for patients and to improve the process of creating plans for the nutritionist.
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    • A Design of a Spindle and Mathematical Calculations of the Speed Required for HDPE Plastic Extrusion and Recycled PETG Plastic to Obtain 40 kg/h of Filaments 3 mm Thick

      Robledo, Ana Fernanda; Gambini, Patsy; Vinces, Leonardo; Klusmann, Mirko (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      The present article proposes to show the mathematical design of a spindle and the speed that it requires, using mathematical formulas, to carry out the extrusion process of recycled PETG or HDPE plastic. Speed control in this process is of great importance because the quality of the filament to be obtained will depend on it. The study will be simulated on spindles and casing that are 3640 and 3890 mm long respectively and made of AISI 4140 steel. The spindle casing has 3 types of band resistors, which vary their temperature according to the material to be used: PETG plastic or HDPE plastic. Each band type resistor is found in each section that the spindle has; the screw has 3 stages called the feeding zone, the compression zone, and the dosing zone. The production capacity is 40 kg /h of PETG or HDPE plastic filament 3 mm thick. In conclusion, the present method consists of the mathematical design of a spindle for the extrusion of both materials, calculation of speeds, and the simulation of the behavior of the fluid.
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    • A middle rate of failed extubation is desirable?: Questions unanswered (reply).

      Kapnadak, Siddhartha G; Herndon, Steve E; Burns, Suzanne M; Shim, Y Michael; Enfield, Kyle; Brown, Cynthia; Truwit, Jonathon D; Vinayak, Ajeet G; [email protected] (Elsevier B.V., 2015-12)
      Cartas al editor
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    • A modular mechatronic gripper installed on the industrial robot KUKA KR 60-3 for boxing, unpacking and selecting of beverage bottles

      Andrade, Ronald Gerson Villanueva; Vinces, Leonardo; Lau, Kalun (Springer-Verlag Italia s.r.l., 2022-01-01)
      Nowadays, bottling industries perform inefficient maintenance and transportation sub-processes, such as: boxing, unpacking, and selecting. These functions are performed by workers during long hours, which causes delays in the general production process, risks in the safety of personnel and integrity of the bottles, a tendency to a greater number of errors and especially, severe medical problems caused in the long term. In view of the advantages of industrial automation, it is known that it makes use of the union of engineering knowledge to facilitate procedures and guarantee reliability. This is the case of industrial robots that are increasingly required to optimize numerous systematic strategies in many fields; however, it is complex to develop an autonomous artifact that adapts to variable changes in different environments. Despite the existence of interesting projects for grippers or claws to lift objects, several of them lack adaptability regarding the type of element they handle and among other deficiencies. For these needs, a Modular Mechatronic Gripper was designed and installed on the Industrial Robot KUKA KR 60-3; having characteristics of versatility and dynamism to load and unload 12 glass or plastic bottles, personal or medium size; and all of them at the same time efficiently and safely. Likewise, the automatic machine can be used with different box layouts or different industrial robots, by means of simple component modifications. With the dexterity of the mechatronic system, the time required for the aforementioned sub-processes was reduced by 72% and it is expected to improve the health of the employees.
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    • A novel hybrid approach of gravitational search algorithm and decision tree for twitter spammer detection

      Vives, Luis; Tuteja, Gurpreet Singh; Manideep, A. Sai; Jindal, Sonika; Sidhu, Navjot; Jindal, Richa; Bhatt, Abhishek (World Scientific, 2022-05-01)
      With the increasing popularity of online social networking platforms, the amount of social data has grown exponentially. Social data analysis is essential as spamming activities and spammers are escalating over online social networking platforms. This paper focuses on spammer detection on the Twitter social networking platform. Although existing researchers have developed numerous machine learning methods to detect spammers, these methods are inefficient for appropriately detecting spammers on Twitter due to the imbalance of spam and nonspam data distribution, the involvement of diverse features and the applicability of data mechanisms by spammers to avoid their detection. This research work proposes a novel hybrid approach of the gravitational search algorithm and the decision tree (HGSDT) for detecting Twitter spammers. The individual decision tree (DT) algorithm is not able to address the challenges as it is unstable and ineffective for the higher level of favorable data for a particular attribute. The gravitational search algorithm (GSA) constructs the DTs with improved performance as the gravitational forces act as the information-transferring agents through mass agents. Moreover, the GSA is efficient in handling the data of higher dimensional search space. In the HGSDT approach, the construction of the DT and splitting of nodes are performed with the heuristic function and Newton's laws. The performance of the proposed HGSDT approach is determined for the Social Honeypot dataset and 1KS-10KN dataset by conducting three different experiments to analyze the impact of training data size, features and spammer ratio. The result of the first experiment shows the need of a higher proportion of training data size, the second experiment signifies the more importance of textual content-based features compared to the other feature categories and the third experiment indicates the requirement of balanced data to attain the effective performance of the proposed approach. The overall performance comparison indicates that the proposed HGSDT approach is superior to the incorporated machine learning methods of DT, support vector machine and back propagation neural network for detecting Twitter spammers.
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    • A Novel Steganography Technique for SDTV-H.264/AVC Encoded Video

      Di Laura, Christian; Pajuelo, Diego; Kemper, Guillermo (Hindawi Publishing Corporation, 2016-04)
      Today, eavesdropping is becoming a common issue in the rapidly growing digital network and has foreseen the need for secret communication channels embedded in digital media. In this paper, a novel steganography technique designed for Standard Definition Digital Television (SDTV) H.264/AVC encoded video sequences is presented. The algorithm introduced here makes use of the compression properties of the Context Adaptive Variable Length Coding (CAVLC) entropy encoder to achieve a low complexity and real-time inserting method. The chosen scheme hides the private message directly in the H.264/AVC bit stream by modifying the AC frequency quantized residual luminance coefficients of intrapredicted I-frames. In order to avoid error propagation in adjacent blocks, an interlaced embedding strategy is applied. Likewise, the steganography technique proposed allows self-detection of the hidden message at the target destination. The code source was implemented by mixing MATLAB 2010 b and Java development environments. Finally, experimental results have been assessed through objective and subjective quality measures and reveal that less visible artifacts are produced with the technique proposed by reaching PSNR values above 40.0 dB and an embedding bit rate average per secret communication channel of 425 bits/sec. This exemplifies that steganography is affordable in digital television.
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    • A population-based study of cervical cytology findings and human papillomavirus infection in a suburban area of Thailand

      Phoolcharoen, Natacha; Kantathavorn, Nuttavut; Sricharunrat, Thaniya; Saeloo, Siriporn; Krongthong, Waraphorn (Elsevier B.V., 2017-08)
      Cartas al Editor
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    • A randomised controlled trial to evaluate a medication monitoring system for TB treatment

      Acosta, J.; Flores, P.; Alarcón, M.; Grande-Ortiz, M.; Moreno-Exebio, L.; Puyen, Z. M. (International Union Against Tuberculosis and Lung Disease, 2022-01-01)
      BACKGROUND: Adherence to TB treatment and therefore treatment success could be improved using digital adherence technology. OBJECTIVE: To evaluate the effectiveness of a medication event reminder monitor system (MERM) on treatment success and treatment adherence in patients with drug-susceptible pulmonary TB in Perú. METHODS: This was an experimental, randomised, open-label, controlled study conducted among patients in the second phase of TB treatment. The intervention group received their medications through MERM with the support of a treatment monitor, whereas the control group used the usual strategy. Participants were followed until they completed the 54 doses of the second phase of treatment. RESULTS: The study included 53 patients in each group; four in the intervention group withdrew from the study. Treatment success was significantly more frequent in the MERM group (RR 1.15, 95% CI 1.02–1.30; P = 0.0322). There was no significant difference in the adherence outcomes; however, the percentage of patients who missed at least one dose and patients with more than 10% of total doses missed were lower in the intervention group. CONCLUSION: The use of MERM in the second phase of treatment showed a significant improvement in the treatment success rate in patients with drug-susceptible pulmonary TB.
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    • A Shocking Cystory

      Cayo Quiñe, Alexandra; Bustamante Voysest, Rossi; Martínez Vargas, Valeria (Elsevier B.V., 2015-04-09)
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    • A Strategy of Potential Fields and Neural Networks in the Control of an Autonomous Vehicle Within Dangerous Environments

      Chávez, Luisa; Cortez, Angel; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      This article focuses on the development of an autonomous navigation system by generating real-time 3D maps of different urban environments with different properties within simulation software. This system used the Pioneer 3-DX vehicle, a LiDAR sensor, GPS, and a gyroscope. For the elaboration of the trajectory, the mathematical tool of artificial potential fields was used, which will generate an attractive field to a dynamic goal identified by the robot and repulsive to the obstacles present in the environment, recognized with great precision thanks to the use of a neural network. The topology neural network 8–16–32 was developed using forward propagation, reverse propagation, and gradient descent algorithms. By combining the tools of potential fields and neural networks, a path was traced through which the robotic system will be able to move freely under an off-center point kinematic control algorithm. Finally, a 3D map of the environment was obtained to provide information on the morphology and most outstanding characteristics of the deployment environment to users who use the system.
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