Hypervelocity dust particle impacts observed by the Giotto Magnetometer and Plasma Experiments

We report thirteen very short events in the magnetic field of the inner magnetic pile‐up region of comet Halley observed by the Giotto magnetometer experiment together with simultaneous plasma data obtained by the Johnstone plasma analyzer and the ion mass spectrometer experiments. The events are due to dust impacts in the milligram range on the spacecraft at the relative velocity between the cemetery dust and the spacecraft of 68 km/sec. They are generally consistent with dust impact events derived from spacecraft attitude perturbations by the Giotto camera [Curdt and Keller, private communication]. Their characteristic shape generally involves a sudden decrease in magnetic field magnitude, a subsequent overshoot beyond initial field values and an asymptotic approach to the initial field somewhat reminiscent of the magnetic field signature after the AMPTE releases in the solar wind. These observations give a new way of analyzing ultra‐fast dust particles incident on a spacecraft

Efectos de un apoyo co-regulatorio en tareas colaborativas con textos multimedia

En este trabajo se analizan los efectos de un apoyo dirigido a favorecer la puesta en juego de los procesos de co-regulación, es decir, los procesos implicados en la gestión de la actividad de colaboración, en una tarea grupal de comprensión de un texto multimedia. Participaron en el estudio 60 estudiantes universitarios mexicanos agrupados en 20 triadas Cada triada fue asignada a una de las dos condiciones: con apoyo co-regulatorio y sin apoyo. Los estudiantes realizaron una tarea colaborativa de comprensión lectora, utilizando la estrategia de construcción colaborativa de mapas conceptuales a partir de información presentada en un material multimedia. El rendimiento en dicha tarea fue valorado de acuerdo con la calidad de los mapas conceptuales elaborados y se valoró el nivel de colaboración percibido por cada integrante de los equipos. El análisis cuantitativo de los resultados muestra la existencia de efectos significativos en el nivel de colaboración alcanzado en los equipos, a favor de la condición con apoyo co-regulatorio. En las conclusiones se señalan los alcances de estos resultados para el diseño y la aplicación de intervenciones específicas (innovadoras, complejas y de tipo colaborativo), basadas en la utilización de materiales multimedia

Social Representations of Bogota - Colombia Inhabitants Regarding a Conditional Cash Transfer Policy

The current article shows the development of a research process whose main objective was to explain the influence of the social representations of the inhabitants of Bogotá, Colombia in the implementation of the public policy of conditional cash transfers “Más Familias en Acción.” For this aim, a qualitative study of hermeneutic design was conducted with beneficiaries of the program and non-beneficiaries, in which, through the application of semi-structured interviews, the most frequent social representations about subsidies, policies, work, education, health, among other relevant issues related to this public policy were identified and once the information was coded by using the Atlas.ti software, interpretation of results was done making possible to establish a relationship between the social representations found and the implementation of “Más Familias en Acción,” leading to the understanding of how social representations as sets of ideas, values and practices that become a social code that denominates the individual and collective reality, have influence both in the way in which the beneficiaries of the program conceive their social reality, and in the sense they give to the program, as well as in their articulation and interaction with it, enabling its implementation, which may or may not occur according to the objectives of public policy

Adoption of the personas technique in the open source software development process

The growth in the number of non-developer open source software (OSS) application users and the escalating use of these applications have led to the need and interest in developing usable OSS. OSS communities do not generally know how to apply usability techniques and are unclear about which techniques to use in each activity of the development process. The aim of our research is to adopt the Personas usability technique in the PSeInt OSS project and determine the feasibility of adapting the technique for application. To do this, we participated as volunteers in the project. We used the case study research method during technique application and participation in the community. As a result, we identified adverse conditions that were an obstacle to technique application and modified the technique to make it applicable. We can conclude from our experience that these changes were helpful for applying the technique, although it was not easy to recruit OSS users to participate in usability technique applicationThis research has been partly funded by several organizations, including the Government of Ecuador’s Secretariat of Higher Education, Science, Technology and Innovation (SENESCYT) through a scholarship and the State Technical University of Quevedo through doctoral training scholarships for university professors. Also this research was funded by the Spanish Ministry of Education, Culture and Sports FLEXOR and “Realizando Experimentos en la Industria del Software: Comprensión del Paso de Laboratorio a la Realidad” projects (TIN2014-52129-R and TIN2014-60490-P, respectively) and the eMadrid-CM “Investi-gación y Desarrollo de Tecnologías Educativas en la Comunidad de Madrid” project (S2013/ICE-2715

Hyperbolic (1,2)-knots in S^3 with crosscap number two and tunnel number one

A knot in S^3 is said to have crosscap number two if it bounds a once-punctured Klein bottle but not a Moebius band. In this paper we give a method of constructing crosscap number two hyperbolic (1,2)-knots with tunnel number one which are neither 2-bridge nor (1,1)-knots. An explicit infinite family of such knots is discussed in detail.Comment: 31 pages, 11 figures. To appear in Topology and its Applications (2008

Software engineering group work - Personality, patterns and performance

This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in SIGMIS-CPR '10, http://dx.doi.org/10.1145/1796900.1796921Proceedings of the 2010 Special Interest Group on Management Information System's 48th annual conference on Computer personnel research on Computer personnel research (Vancouver, BC, Canada)Software Engineering has been a fundamental part of many computing undergraduate courses for a number of years. Although many of the tools and techniques used to undertake software engineering have changed, the assessment has typically stayed the same. Students are commonly tasked with producing a number of software artefacts, for example designs using the Unified Modelling Language (UML). We recently attempted to extend the software engineering experience for a group of second year students with them participating in groups that attempt to replicate industrial practice. This paper reports our investigation into the correlation between the personality of group members, their approach with respect to using design patterns and their learning achievements

Selective Harmonic Elimination Model Predictive Control for Multilevel Power Converters

© 2016 IEEE. In this study, a model predictive control (MPC) strategy that combines finite-control-set MPC with selective harmonic elimination (SHE) modulation pattern in its formulation is proposed to govern multilevel power converters. Based on a desired operating point for the system state (converter current reference), an associated predefined SHE voltage pattern is obtained as a required steady-state control input reference. Then, the cost function is formulated with the inclusion of both system state and control input references. According with the proposed reference and cost function formulation, the predictive controller prefers to track the converter output current reference in transients, while preserving the SHE voltage pattern in steady state. Hence, as evidenced by experimental results, a fast dynamic response is obtained throughout transients while a predefined voltage and current spectrum with low switching frequency is achieved in steady state