Enabling Practical IPsec authentication for the Internet

On the Move to Meaningful Internet Systems 2006: OTM 2006 Workshops (First International Workshop on Information Security (IS'06), OTM Federated Conferences and workshops). Montpellier, Oct,/Nov. 2006There is a strong consensus about the need for IPsec, although its use is not widespread for end-to-end communications. One of the main reasons for this is the difficulty for authenticating two end-hosts that do not share a secret or do not rely on a common Certification Authority. In this paper we propose a modification to IKE to use reverse DNS and DNSSEC (named DNSSEC-to-IKE) to provide end-to-end authentication to Internet hosts that do not share any secret, without requiring the deployment of a new infrastructure. We perform a comparative analysis in terms of requirements, provided security and performance with state-of-the-art IKE authentication methods and with a recent proposal for IPv6 based on CGA. We conclude that DNSSEC-to-IKE enables the use of IPsec in a broad range of scenarios in which it was not applicable, at the price of offering slightly less security and incurring in higher performance costs.Universidad de Montpellier IIPublicad

Dynamical evolution of a doubly-quantized vortex imprinted in a Bose-Einstein Condensate

The recent experiment by Y. Shin \emph{et al.} [Phys. Rev. Lett. \textbf{93}, 160406 (2004)] on the decay of a doubly quantized vortex imprinted in $^{23}$Na condensates is analyzed by numerically solving the Gross-Pitaevskii equation. Our results, which are in very good quantitative agreement with the experiment, demonstrate that the vortex decay is mainly a consequence of dynamical instability. Despite apparent contradictions, the local density approach is consistent with the experimental results. The monotonic increase observed in the vortex lifetimes is a consequence of the fact that, for large condensates, the measured lifetimes incorporate the time it takes for the initial perturbation to reach the central slice. When considered locally, the splitting occurs approximately at the same time in every condensate, regardless of its size.Comment: 5 pages, 4 figure

Enhancement of Student Learning Through the Use of a Hinting Computer e-Learning System and Comparison with Human Teachers

This paper reports the results of an experiment in a Computer Architecture Laboratory course classroom session, in which students were divided into two groups for interaction both with a hinting e-learning system and with human teachers generating hints. The results show that there were high learning gains for both groups, demonstrating the effectiveness of the human teachers as well as of the computer-based hinting e-learning system even without the use of adaptive and personalization capabilities. In addition, in the worst case, the difference in favor of human teachers (with a low student-to-teacher ratio of 13.5 students per teacher) would not be significant with respect to the e-learning system, so the computer-based system can replace teachers without a significant loss of effectiveness.This work was supported in part by the Learn3 project TIN2008-05163/TSI within the Spanish “Plan Nacional de I+D+I,” and by the Madrid regional community project eMadrid S2009/TIC-1650.Publicad

Using bluetooth to implement a pervasive indoor positioning system with minimal requirements at the application level

Proyecto CCG10-UC3M/TIC-4992 de la Comunidad Autónoma de Madrid y la Universidad Carlos III de MadridPublicad

Deciding on different hinting techniques in assessments for intelligent tutoring systems

Intelligent Tutoring Systems (ITSs) must take advantage of their high computing capabilities and capacity for information retrieval in order to provide the most effective methodologies for improving students' learning. One type of ITS provides assessments to students and some help as a hint, when they do not know how to solve a problem. Our thesis is that the type of hinting techniques used without changing the contents can influence the learning gains and aptitudes of students. We have implemented some hinting techniques as an extension to the XTutor ITS. We found that some hinting techniques can produce a signi cant increase in students' knowledge with respect to others, but the improvement and direction of the comparison depended on some other factors such as the topics to which it was applied. We conclude that proper adaptation of hinting techniques based on different information of the systems will imply better student learning gains. In addition, the results of a student survey, which includes the students' ratings of the different hinting features they interacted with, leads to high variances, which reinforce the idea of the importance of adaptation of hinting techniques in these types of systems.This work was supported in part by the MEC-CICYT Learn3 project TIN2008-05163/TSI (Spanish Ministry of Science and Education, Programa Nacional de Tecnologías de la Información y de las Comunicaciones), and the e-Madrid project S2009/TIC-1650 (Madrid Regional Community).Publicad

Sending learning pills to mobile devices in class to enhance student performance and motivation in network services configuration courses

Teaching electrical and computer software engineers how to configure network services normally requires the detailed presentation of many configuration commands and their numerous parameters. Students tend to find it difficult to maintain acceptable levels of motivation. In many cases, this results in their not attending classes and not dedicating enough time to acquire the required competencies. This paper describes a successful experiment that was able to improve student class attendance, performance, and motivational patterns by using mobile devices in class to provide students with contextualized learning pills. A learning pill is a simple exercise that summarizes some of the key concepts explained in class and promotes reflection and self-study. Each student attending a particular lecture or laboratory session automatically receives a learning pill on his or her mobile phone just after the related concept has been presented. This paper details the scenario used in the experiment and analyzes the performance and motivational patterns of 170 students at the Higher Polytechnic School, Carlos III University of Madrid, Leganes, SpainThis work was supported by the ARTEMISA project TIN2009- 14378-C02-02 within the Spanish “Plan Nacional de I+D+I” and the Madrid regional community projects S2009/TIC-1650 and CCG10-UC3M/TIC-4992.Publicad

Generación de imagen tridimensional de objetos sumergidos en aguas turbias

This article presents the design and implementation of a novel method to generate 3D coordinates from the projection of a laser line over a solid object and the processing of the images obtained during scanning. The result obtained is a 3D model of an isometric view that provides the possibility of being seen from different perspectives under a virtual environment. The methodology is applied in the capture and reconstruction of 3D images of objects submerged in murky waters.Este artículo presenta el diseño e implementación de un novedoso método para generar coordenadas tridimensionales a partir de la proyección de una línea láser sobre un objeto sólido y el procesamiento de las imágenes obtenidas durante el escaneo. El resultado obtenido es un modelo tridimensional de una vista isométrica que brinda la posibilidad de ser visto desde diferentes perspectivas bajo un ambiente virtual. La metodología es aplicada en la captura y reconstrucción de imágenes tridimensionales de objetos sumergidos en aguas turbias

Evaluating the Effectiveness and Motivational Impact of Replacing a Human Instructor by Mobile Devices for Teaching Network Services Configuration to Telecommunication Engineering Students

Proceedings of: 10th IEEE International Conference on Advanced Learning Technologies (ICALT 2010). Sousse, Tunisia, 5-7 July 2010.The introduction of mobile technologies in class provide instructors with tools for contextualized, active, situated, any-time any-where learning. In fact, the role of the instructor can be partially delegated to the student by the use of a mobile device. This paper assesses if this delegation can be brought to the limit of eliminating the need of the physical presence of the instructor in the particular context of a situated learning environment consisting of a server room where third year Telecommunication Engineering students learn how to configure network services such as DNS, SMTP and HTTP. The paper presents the results of two experiments inside the "advanced telematic applications" course at the Carlos III University of Madrid. Two groups of students participated in the experiments, one following traditional instructor based classes and the other using NFC enabled mobile phones. The paper analyzes both learning increments and motivational aspects.The work presented in this paper has been partially funded by the project Learn3 TIN2008-05163/TSI within the Spanish “Plan Nacional de I+D+I”, the SOLITE CYTED Program 508AC0341 and the e-Madrid project S2009/TIC-1650 funded by the Madrid regional Government. Thanks to INNOVISION for providing the NFC tags for this experiment. Gustavo Ramirez-Gonzalez is funded by the EU Programme Alban, scholarship number E06D101768CO and by the Universidad del Cauca.Publicad

Magiclearning: a serious game for learning based in a magic world

This paper presents a new software educational system called MagicLearning that we have designed and implemented. Magic Learning enables each student to be in a multimedia virtual world in which he/she is a magician. The magician has to find several educational challenges (such as questions, crosswords, or reading contents) that are in the magic world and, depending on his/her performance, can then obtain various magic powers (such as invisibility, different types of attacks, or robbing colleagues' notes). The student can apply these powers against monsters, other players or himself/herself. As a result, students will experience more enjoyment while they are learning, so we can expect student learning and motivation to improve. The MagicLearning system also generates adaptive notes for each student related to the specific student interactions, meaning that the better notes a student produces, the better their performance in the game will be.Work partially funded by the Learn3 project TIN2008-05163/TSI and the EEE project TIN2011-28308-C03-1 within the Spanish \Plan Nacional de I+D+I", and the Madrid regional community project eMadrid S2009/TIC-1650.Publicad

An adaptive and innovative question-driven competition-based intelligent tutoring system for learning

Teaching electrical and computer software engineers how to configure network services normally requires the detailed presentation of many configuration commands and their numerous parameters. Students tend to find it difficult to maintain acceptable levels of motivation. In many cases, this results in their not attending classes and not dedicating enough time to acquire the required competencies. This paper describes a successful experiment that was able to improve student class attendance, performance, and motivational patterns by using mobile devices in class to provide students with contextualized learning pills. A learning pill is a simple exercise that summarizes some of the key concepts explained in class and promotes reflection and self-study. Each student attending a particular lecture or laboratory session automatically receives a learning pill on his or her mobile phone just after the related concept has been presented. This paper details the scenario used in the experiment and analyzes the performance and motivational patterns of 170 students at the Higher Polytechnic School, Carlos III University of Madrid, Leganes, Spain.Work partially funded by the Learn3 project TIN2008-05163/TSI and the EEE project TIN 2011-28308-CO3-1 within the Spanish ‘‘Plan Nacional de I+D+I’’, and the Madrid regional community project eMadrid S2009/TIC-1650