302 research outputs found
Caracterización de un equipo de usuario mediante técnicas de fingerprinting
Este trabajo final de carrera pretende ser un estudio sobre fingerprinting. Para
ello, se ha recopilado información sobre los tipos de fingerprinting y las
características de las pruebas que hacen las aplicaciones que implementan
este tipo de función. También se ha realizado un estudio del RFC 1122,
requerimientos para un host de Internet, donde se explican como deben estar
configurados los diferentes protocolos de las capas de enlace, internet y
transporte. Aplicando técnicas de fingerprinting se detectarán las diferencias
de implementación de una pila de protocolos TCP/IP en relación con el RFC
1122. También se analiza la influencia de un firewall sobre las pruebas que
realiza una aplicación de fingerprinting.
Se han analizado dos aplicaciones de fingerprinting que son ampliamente
utilizadas por los hackers: nmap, la más conocida, y Winfingerprinting. De
estas aplicaciones se ha estudiado como realizan las pruebas y que tipos de
resultados dan.
Por último se describe como se ha realizado una aplicación de fingerpriting.
Esta aplicación puede enviar paquetes ICMP y TCP. Se puede variar cada uno
de los campos de los que están formados los paquetes para así poder realizar
todo tipo de pruebas de tipo fingerprinting
Re-engineering the ant colony optimization for CMP architectures
[EN] The ant colony optimization (ACO) is inspired by the behavior of real ants, and as a bioinspired method, its underlying computation is massively parallel by definition. This paper shows re-engineering strategies to migrate the ACO algorithm applied to the Traveling Salesman Problem to modern Intel-based multi- and many-core architectures in a step-by-step methodology. The paper provides detailed guidelines on how to optimize the algorithm for the intra-node (thread and vector) parallelization, showing the performance scalability along with the number of cores on different Intel architectures, reporting up to 5.5x speedup factor between the Intel Xeon Phi Knights Landing and Intel Xeon v2. Moreover, parallel efficiency is provided for all targeted architectures, finding that core load imbalance, memory bandwidth limitations, and NUMA effects on data placement are some of the key factors limiting performance. Finally, a distributed implementation is also presented, reaching up to 2.96x speedup factor when running the code on 3 nodes over the single-node counterpart version. In the latter case, the parallel efficiency is affected by the synchronization frequency, which also affects the quality of the solution found by the distributed implementation.This work was partially supported by the Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia under Project 20813/PI/18, and by Spanish Ministry of Science, Innovation and Universities as well as European Commission FEDER funds under Grants TIN2015-66972-C5-3-R, RTI2018-098156-B-C53, TIN2016-78799-P (AEI/FEDER, UE), and RTC-2017-6389-5. We acknowledge the excellent work done by Victor Montesinos while he was doing a research internship supported by the University of Murcia.Cecilia-Canales, JM.; García Carrasco, JM. (2020). Re-engineering the ant colony optimization for CMP architectures. The Journal of Supercomputing (Online). 76(6):4581-4602. https://doi.org/10.1007/s11227-019-02869-8S45814602766Yang XS (2010) Nature-inspired metaheuristic algorithms. Luniver Press, LebanonAkila M, Anusha P, Sindhu M, Selvan Krishnasamy T (2017) Examination of PSO, GA-PSO and ACO algorithms for the design optimization of printed antennas. In: IEEE Applied Electromagnetics Conference (AEMC)Dorigo M, Stützle T (2004) Ant colony optimization. A bradford book. The MIT Press, CambridgeCecilia JM, García JM, Nisbet A, Amos M, Ujaldón M (2013) Enhancing data parallelism for ant colony optimization on GPUs. J Parallel Distrib Comput 73(1):42–51Dawson L, Stewart I (2013) Improving ant colony optimization performance on the GPU using CUDA. In: IEEE Conference on Evolutionary Computation, pp 1901–1908Llanes A, Cecilia JM, Sánchez A, García JM, Amos M, Ujaldón M (2016) Dynamic load balancing on heterogeneous clusters for parallel ant colony optimization. Cluster Comput 19(1):1–11Cecilia JM, Llanes A, Abellán JL, Gómez-Luna J, Chang L, Hwu WW (2018) High-throughput ant colony optimization on graphics processing units. J Parallel Distrib Comput 113:261–274Lloyd H, Amos M (2016) A Highly Parallelized and Vectorized Implementation of Max–Min Ant System on Intel Xeon Phi. In: IEEE computational intelligenceTirado F, Barrientos RJ, González P, Mora M (2017) Efficient exploitation of the Xeon Phi architecture for the ant colony optimization (ACO) metaheuristic. J Supercomput 73(11):5053–5070Montesinos V, García JM (2018) Vectorization strategies for ant colony optimization on intel architectures. Parallel Computing is Everywhere. IOS Press, Amsterdam, pp 400–409Lawler E, Lenstra J, Kan A, Shmoys D (1987) The Traveling salesman problem. Wiley, New YorkMontesinos V (June 2018) Performance analysis of ant colony optimization on intel architectures. Master’s Thesis, University of Murcia (Spain)Lloyd H, Amos M (2017) Analysis of independent roulette selection in parallel ant colony optimization. In: Genetic and Evolutionary Computation Conference, ACM, pp 19–26Dorigo M (1992) Optimization, learning and natural algorithms. Ph.D. Thesis, Politecnico di Milano, ItalyDuran A, Klemm M (2012) The intel many integrated core architecture. In: Internal Conference on High Performance Computing and Simulation (HPCS), pp 365–366The OpenMP API specification for parallel programming. URL: https://www.openmp.org . [Last accessed 14 June 2018]The Message Passing Interface (MPI) standard. URL: http://www.mcs.anl.gov/research/projects/mpi/ . [Last accessed 15 June 2018]Vladimirov A, Asai R (2016) Clustering modes in Knights landing processors: developer’s guide. Colfax international. URL: https://colfaxresearch.com/knl-numa/ . [Last accessed: 16 June 2018]Intel Developer Zone. URL: https://software.intel.com/en-us/modern-code . [Last accessed 02 Oct 2018]Pearce M (2018) What is code modernization? Intel developer zone. URL: http://software.intel.com/en-us/articles/what-is-code-modernization . [Last accessed 15 Feb 2018]Stützle T ACOTSP v1.03. Last accessed 15 Feb 2018. URL: http://iridia.ulb.ac.be/~mdorigo/ACO/downloads/ACOTSP-1.03.tgzReinelt G (1991) TSPLIB—a traveling salesman problem library. ORSA J Comput 3:376–384Crainic TG, Toulouse M (2003) Parallel strategies for meta-heuristics. State-of-the-art handbook in metaheuristics. Kluwer Academic Publishers, Dordrecht, pp 475–513Delévacq A, Delisle P, Gravel M, Krajecki M (2013) Parallel ant colony optimization on graphics processing units. J Parallel Distrib Comput 73(1):52–61Skinderowicz R (2016) The GPU-based parallel ant colony system. J Parallel Distrib Comput 98:48–60Zhou Y, He F, Hou N, Qiu Y (2018) Parallel ant colony optimization on multi-core SIMD CPUs. Future Gener Comput Syst 79:473–487Peake J, Amos M, Yiapanis P, Lloyd H (2018) Vectorized candidate set selection for parallel ant colony optimization. In: Genetic and Evolutionary Computation Conference, ACM, pp 1300–1306Stützle T (1998) Parallelization strategies for ant colony optimization. In: Eiben AE, Bäck T, Schoenauer M, Schwefel HP (eds) Parallel problem solving from nature—PPSN V. PPSN. Lecture Notes in Computer Science, vol 1498. Springer, Berlin, HeidelbergAbdelkafi O, Lepagnot J, Idoumghar L (2014) Multi-level parallelization for hybrid ACO. In: Siarry P, Idoumghar L, Lepagnot J (eds) Swarm Intelligence Based Optimization. ICSIBO 2014. Lecture Notes in Computer Science, vol 8472. Springer, ChamMichel R, Middendorf M (1998) An island model based ant system with lookahead for the shortest super sequence problem. In: Eiben AE, Bäck T, Schoenauer M, Schwefel HP (eds) Parallel problem solving from nature— PPSN V. PPSN. Lecture Notes in Computer Science, vol 1498. Springer, Berlin, HeidelbergChen L, Sun H, Wang S (2008) Parallel implementation of ant colony optimization on MPP. In: International Conference on Machine Learning and CyberneticsLin Y, Cai H, Xiao J, Zhang J (2007) Pseudo parallel ant colony optimization for continuous functions. In: International Conference on Natural Computatio
DC-Voltage-Ratio Control Strategy for Multilevel Cascaded Converters Fed With a Single DC Source
Recently, a multilevel cascaded converter fed with a single DC source has been presented. An analysis of the steady-state working limits of this type of converter is presented in this paper. Limits of the maximum output voltage and the minimum and maximum loading conditions for stable operation of the converter are addressed. In this paper, a way to achieve any DC voltage ratio (inside the stable operation area of the converter) between the H-bridges of the single-DC-source cascaded H-bridge converter is presented. The proposed DC-voltage-ratio control is based on a time-domain modulation strategy that avoids the use of inappropriate states to achieve the DC-voltage-ratio control. The proposed technique is a feedforward-modulation technique which takes into account the actual DC voltage of each H-bridge of the converter, leading to output waveforms with low distortion. In this way, the dc voltage of the floating H-bridge can be controlled while the output voltage has low distortion independently of the desired DC voltage ratio. Experimental results from a two-cell cascaded converter are presented in order to validate the proposed DC-voltage-ratio control strategy and the introduced concepts.Ministerio de Ciencia y Tecnología TEC2006-03863Junta de Andalucía EXC/2005/TIC-117
A Neural Controller for quasi-resonant converters
A neural controller implementing an energy feedback control law is proposed to improve
the stability and dynamic characteristics of the series resonant converter (SRC). The cnert)' feedback
control is introduced and analysed in discrete time domain. A novel formulation of the control law
is suggested. The adaptive control law is learnt by an analog neural network (ANN). An easy imple·
mentation of this controller is proposed and applied to a SRC circuit. Simulation results show a good
improvement in the SRC response and confirm the validity of the controller
Analysis of the power balance In the cells of a multilevel cascaded H-Bridge converter
Multilevel cascaded H-Bridge converters (CHB)
have been presented as a good solution for high power applications.
In this way, several control and modulation techniques
have been proposed for this power converter topology. In this
paper the steady state power balance in the cells of the single
phase two cell CHB is studied. The capability to be supplied with
active power from the grid or to deliver active power to the grid
in each cell is analyzed according to the dc-link voltages and
the desired ac output voltage value. Limits of the maximum and
minimum input active power for stable operation of the CHB are
addressed. Simulation results are shown to validate the presented
analysis
Feed-forward Space Vector Modulation for Single-Phase Multilevel Cascade Converters with any DC voltage ratio
Modulation techniques for multilevel converters
can create distorted output voltages and currents if the DC link
voltages are unbalanced. This situation can be avoided if the
instantaneous DC voltage error is not taken into account in the
modulation process. This paper proposes a feed-forward space
vector modulation method for a single-phase multilevel cascade
converter. Using this modulation technique, the modulated output
voltage of the power converter always generates the reference
determined by the controller even in worst case voltage unbalance
conditions. In addition the possibility of optimizing the DC
voltage ratio between the H-bridges of the power converter is
introduced. Experimental results from a 5kVA prototype are
presented in order to validate the proposed modulation technique
Evaluation of the 3-D finite difference implementation of the acoustic diffusion equation model on massively parallel architectures
The diffusion equation model is a popular tool in room acoustics modeling. The 3-D Finite Difference (3D-FD) implementation predicts the energy decay function and the sound pressure level in closed environments. This simulation is computationally expensive, as it depends on the resolution used to model the room. With such high computational requirements, a high-level programming language (e.g., Matlab) cannot deal with real life scenario simulations. Thus, it becomes mandatory to use our computational resources more efficiently. Manycore architectures, such as NVIDIA GPUs or Intel Xeon Phi offer new opportunities to enhance scientific computations, increasing the performance per watt, but shifting to a different programming model. This paper shows the roadmap to use massively parallel architectures in a 3D-FD simulation. We evaluate the latest generation of NVIDIA and Intel architectures. Our experimental results reveal that NVIDIA architectures outperform by a wide margin the Intel Xeon Phi co-processor while dissipating approximately 50 W less (25%) for large-scale input problems.Ingeniería, Industria y Construcció
A novel space-vector algorithm for multilevel converters based on geometrical considerations using a new sequence control technique
his paper presents a fast and simple space vector modulation algorithm for voltage source multilevel converters for calculating the switching times and the space vectors using simple geometrical considerations. This method provides the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. The low computational cost of the proposed method is always the same and it is independent of the number of levels of the converter. In addition, a new switching sequence control technique is presented for reducing the ripple of the DC-link voltage approximately in 66%
Influence of Personality Traits and Its Interaction with the Phenomenon of Bullying: Multi-Centre Descriptive Study
Bullying affects thousands of teenagers worldwide and has devastating consequences.
Various studies suggest that the personality of teenagers is a risk profile for bullying. The aim of this
study was to analyse the relationship between the personality of teenagers aged 14 to 16 years from
three education centres located in the province of Seville (Spain) and bullying in any of its victim
or aggressor roles. A multi-centre cross-sectional observational descriptive study was conducted
in three education centres in the province of Seville (Spain). The sample consisted of 93 students.
In order to measure the two main variables, the Bull-S test was used for bullying, and the EPQ-J
questionnaire was used for personality traits. A descriptive and correlation analysis was performed
between variables. The results showed that 14% (n = 13) of the sample were detected as victims and
another 14% (n = 13) were detected as aggressors. Statistically significant differences were found
between neuroticism (p = 0.044; Phi = 0.615), sincerity (p = 0.016; V de Cramer = 0.474), and anti-social
behaviour (p = 0.007; Phi = 0.620) with the variables victim/aggressor. Bullies are typically males who
score high on neuroticism and anti-social behaviour, with a tendency towards social dissimulation
Study of the different learning environments using secondary education students’ voices: A class, a multiple case study
El propósito de este trabajo es que el alumnado de ESO, en 4 centros de características
diversas, a través de sus voces, describa sus entornos, identifiquen ventajas e inconvenientes
de cada uno de ellos y áreas de mejora. Basándonos en los trabajos de Peng (2015), Yang,
Bezerik-Gerber y Mino (2013), y Castro-Pérez y Morales-Ramirez (2015), los elementos
del entorno sobre los que vamos a investigar van a estructurarse en: físico, de enseñanza, de
aprendizaje y motivacional. Desarrollaremos un estudio de casos multiple (Stake, 2006) en
cada centro educativo. Utilizaremos la metodología de las voces de los estudiantes, por lo
que el alumnado actuará como co-investigadores y los instrumentos de recogida de datos
serán actividades de aula. Esta metodología se ha usado en otras investigaciones como
medio para explorar las prácticas inclusivas y como medio para mejorar los aprendizajes y
la enseñanza (Adderley et al., 2015; Ainscow y Kaplan, 2005; Messiou, 2006, 2012, 2014)The purpose of this research is to know through secondary students’ voices of 2nd or 3rd
course of 4 High Schools with different characteristics, how they perceive the environments
where they work, the advantages and disadvantages of each, and which areas they want
to change to improve their learning. According to Peng’s, 2015, Yang, Bezerik-Gerber y
Mino’s (2013), and Castro-Pérez y Morales-Ramirez’s (2015) works, the elements of the
environment are structured in accordance with 4 aspects: physical, teaching, learning and
motivational. We are going to develop multiple case studies (Stake, 2006) in each secondary
school. This research also draws on the use of students’ voices. So, learners’ll act as coresearches,
and we collect data using activities. Students’ voices have been used in research
as a way of exploring and developing inclusive practices in schools. Also, as a means of
identifying ways to improve learning and teaching in schools (Ainscow y Kaplan, 2005;
Messiou, 2006, 2012, 2014; Adderley et al., 2015
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