The Polytechnic University of Puerto Rico —commonly referred as Poly or La Poly in Spanish— is a private non-profit university located in San Juan, Puerto Rico. PUPR offers a broad range of technical degrees; specializing in engineering professions. Wikipedia.
Torres A.M.,University of Castilla - La Mancha |
Mateo J.,University of Castilla - La Mancha |
Vicente L.M.,Polytechnic University of Puerto Rico
Multidimensional Systems and Signal Processing | Year: 2016
This research proposes an improved narrowband partial adaptive beamformer analysis using a proposed spherical array. Comparison between the fully and the partial adaptive beamformers is given. The study is performed by investigating performance parameters like the beamformer output signal-to-noise ratio and the beamformer output signal-to-interference-plus-noise ratio both in the steady state and along adaptation. Furthermore, computational complexity and convergence speed of the proposed sensor arrangement are also analyzed and examples are given. The results demonstrate that this beamformer considerably reduces the number of complex operations and features faster convergence speed. © 2016 Springer Science+Business Media New York
Rivera Torres P.J.,University of Vigo |
Serrano Mercado E.I.,Polytechnic University of Puerto Rico |
Llanes Santiago O.,Instituto Superior Polytechnic Jose A Echevarria Cujae |
Anido Rifon L.,University of Vigo
Journal of Intelligent Manufacturing | Year: 2016
Recent developments in intelligent manufacturing have validated the use of probabilistic Boolean networks (PBN) to model failures in manufacturing processes and as part of a methodology for Design Failure Mode and Effects Analysis (DFMEA). This paper expands the application of PBNs in manufacturing processes by proposing the use of interventions in PBNs to model an ultrasound welding process in a preventive maintenance (PM) schedule, guiding the process to avoid failure and extend its useful work life. This bio-inspired, stochastic methodology uses PBNs with interventions to model manufacturing processes under a PM schedule and guides the evolution of the network, providing a new mechanism for the study and prediction of the future behavior of the system at the design phase, assessing future performance, and identifying areas to improve design reliability and system resilience. A process engineer designing manufacturing processes may use this methodology to create new or improve existing manufacturing processes, assessing risk associated with them, and providing insight into the possible states, operating modes, and failure modes that can occur. The engineer can also guide the process and avoid states that can result in failure, and design an appropriate PM schedule. The proposed method is applied to an ultrasound welding process. A PBN with interventions model was simulated and verified using model checking in PRISM, generating data required to conduct inferential statistical tests to compare the effects of probability of failures between the PBN and PBN with Interventions models. The obtained results demonstrate the validity of the proposed methodology. © 2016 Springer Science+Business Media New York
Deschapelles B.,Polytechnic University of Puerto Rico
Journal of Structural Engineering | Year: 2011
The analysis of thin-walled structures has been discussed by many theoreticians who produced seminal works. Unfortunately, these studies are based on mathematical formulations which are not easy to understand by the majority of engineers because the background provided by the undergraduate schools does not cover the solution of complex differential equations or the use of area coordinates in the calculation of cross-section properties. Accordingly, practicing engineers are often at a loss in problems involving nonlinear differential equations or the meaning of an elusive mechanical action called bimoment in the evaluation of longitudinal stresses caused by warping torsion. On the other hand, present day formulations should take advantage of the availability of computers that can easily handle the matrix relations on which the finite element analysis is based. This work presents a new finite element that allows the evasion of the aforementioned complexities. The main novelty is the discussion of a nonnodal degree of freedom that efficiently captures the possible shear flow along the longitudinal edges of a beam-column element. © 2011 American Society of Civil Engineers.
Geigel A.,Polytechnic University of Puerto Rico
Journal of Computer Security | Year: 2013
This paper presents a proof of concept of a neural network Trojan. The neural network Trojan consists of a neural network that has been trained with a compromised dataset and modified code. The Trojan implementation is carried out by insertion of a malicious payload encoded into the weights alongside with the data of the intended application. The neural Trojan is specifically designed so that when a specific entry is fed into the trained neural network, it triggers the interpretation of the data as payload. The paper presents a background on which this attack is based and provides the assumptions that make the attack possible. Two embodiments of the attack are presented consisting of a basic backpropagation network and a Neural Network Trojan with Sequence Processing Connections (NNTSPC). The two alternatives are used depending on the underlying circumstances on which the compromise is launched. Experimental results are carried out with synthetic as well as a chosen existing binary payload. Practical issues of the attack are also discussed, as well as a discussion on detection techniques. © 2013-IOS Press and the authors. All rights reserved.
Jordan-Conde Z.,Polytechnic University of Puerto Rico |
Mennecke B.,Iowa State University |
Townsend A.,Iowa State University
Computers in Human Behavior | Year: 2014
During the last decade, online social networks such as Facebook™ (Facebook) grew rapidly in popularity and this was due in no small measure to use of these media by adolescents. For many teenagers and young adults, Facebook represents a social institution that can be used by adolescents not only for sharing basic information and for connecting with others, but also as a platform for exploring and divulging information about their identities. To examine issues related to questions about the formation and disclosure of identity-related information by late adolescents, this study investigates the relationship between disclosures of intimate information by late adolescents through Facebook and their stage of psychosocial development. To examine disclosure behaviors of young college students on Facebook, we conducted focus groups in conjunction with a content analysis of Facebook profiles. Findings point to an extended adolescence period resting on the identity construction dilemma posed by digital social networks. © 2013 Elsevier Ltd. All rights reserved.