Dynamic group formation in mobile computer supported collaborative learning environment

Forming suitable learning groups is one of the factors that determine the efficiency of collaborative learning activities. However, only a few studies were carried out to address this problem in the mobile learning environments. In this paper, we propose a new approach for an automatic, customized, and dynamic group formation in Mobile Computer Supported Collaborative Learning (MCSCL) contexts. The proposed solution is based on the combination of three types of grouping criteria: learner’s personal characteristics, learner’s behaviours, and context information. The instructors can freely select the type, the number, and the weight of grouping criteria, together with other settings such as the number, the size, and the type of learning groups (homogeneous or heterogeneous). Apart from a grouping mechanism, the proposed approach represents a flexible tool to control each learner, and to manage the learning processes from the beginning to the end of collaborative learning activities. In order to evaluate the quality of the implemented group formation algorithm, we compare its Average Intra-cluster Distance (AID) with the one of a random group formation method. The results show a higher effectiveness of the proposed algorithm in forming homogenous and heterogeneous groups compared to the random method.

Cost-effective and lightweight mobile units for MixAR: A comparative trial among different setups

Cultural heritage has arousing the interest of the general public (e.g. tourists), resulting in the increasing number of visitations to archaeological sites. However, many buildings and monuments are severely damaged or completely destroyed, which doesn’t allow to get a full experience of “travelling in time”. Over the years, several Augmented Reality (AR) approaches were proposed to overcome these issues by providing three-dimensional visualization of reconstructed ancient structures in situ. However, most of these systems were made available through heavy and expensive technological bundles. Alternatively, MixAR intends to be a lightweight and cost-effective Mixed Reality system which aims to provide the visualization of virtual ancient buildings reconstructions in situ, properly superimposed and aligned with real-world ruins. This paper proposes and compares different AR mobile units setups to be used in the MixAR system, with low-cost and lightweight requirements in mind, providing different levels of immersion. It was propounded four different mobile units, based on: a laptop computer, a single-board computer (SBC), a tablet and a smartphone, which underwent a set of tests to evaluate their performances. The results show that mobile units based on laptop computer and SBC reached a good overall performance while mobile units based on tablet and smartphone did not meet such a satisfactory result even though they are acceptable for the intended use.

MixAR mobile prototype: visualizing virtually reconstructed ancient structures in situ

Archeology and related areas have a special interest on cultural heritage sites since they provide valuable information about past civilizations. However, the ancient buildings present in these sites are commonly found in an advanced state of degradation which difficult the professional/expert analysis. Virtual reconstructions of such buildings aim to provide a digital insight of how these historical places could have been in ancient times. Moreover, the visualization of such models has been explored by some Augmented Reality (AR) systems capable of providing support to experts. Their compelling and appealing environments have also been applied to promote the social and cultural participation of general public. The existing AR solutions regarding this thematic rarely explore the potential of realism, due to the following lacks: the exploration of mixed environments is usually only supported for indoors or outdoors, not both in the same system; the adaptation of the illumination conditions to the reconstructed structures is rarely addressed causing a decrease of credibility. MixAR [1] is a system concerned with those challenges, aiming to provide the visualization of virtual buildings augmented upon real ruins, allowing soft transitions among its interiors and exteriors and using relighting techniques for a faithful interior illumination, while the user freely moves in a given cultural heritage site, carrying a mobile unit. Regarding the focus of this paper, we intend to report the current state of MixAR mobile unit prototype, which allows visualizing virtual buildings – properly aligned with real-world structures – based on user's location, during outdoor navigation. In order to evaluate the prototype performance, a set of tests were made using virtual models with different complexities.

Identifying finger postures when interacting with the touch screen of mobile devices

This study presents the results of preliminary test on the interaction between fingertip and touch screen. The objective of this study is to identify the fingertip posture when interacting with touch screen devices. Ten participants, 7 males and 3 females, participated in this study. The participants were asked to touch targets on the mobile devices screen by tapping them sequentially and connecting them. The participants performed the tasks in a sitting posture. A tablet with 10 inches screen and a mobile phone with 4 inches screen were used in the study. The results showed that all participants dominantly used their thumb to interact with the mobile phone in single and two hands postures. The common thumb posture adopted by the participants is the combination of the 60° pitch and 0° roll angles. While for interaction with tablet in various postures observed in the study, the participants commonly used their index fingers in the combination of 60° pitch and 0° roll angles. This study also observed the participant with long finger nails touched targets on the mobile devices screen by using her index or middle fingers very low pitch.

Improving quality of medical service with mobile health software

An increasing number of m-Health applications are being developed benefiting health service delivery. In this paper, a new methodology based on the principle of calm computing applied to diagnostic and therapeutic procedure reporting is proposed. A mobile application was designed for the physicians of one of the Portuguese major hospitals, which takes advantage of a multi-agent interoperability platform, the Agency for the Integration, Diffusion and Archive (AIDA). This application allows the visualization of inpatients and outpatients medical reports in a quicker and safer manner, in addition to offer a remote access to information. This project shows the advantages in the use of mobile software in a medical environment but the first step is always to build or use an interoperability platform, flexible, adaptable and pervasive. The platform offers a comprehensive set of services that restricts the development of mobile software almost exclusively to the mobile user interface design. The technology was tested and assessed in a real context by intensivists.

Producing LFT composite parts for large consumption markets from thermoplastic powder-coated towpregs

Thermoplastic matrix composites are receiving increasing interest in last years. This is due to several advantageous properties and speed of processing of these materials as compared to their thermoset counterparts. Among thermoplastic composites, Long Fibre Thermoplastics (LFTs) have seen the fastest growth, mainly due to developments in the automotive sector. LFTs combine the (semi-)structural material properties of long (>1 cm) fibres, with the ease and speed of thermoplastic processing. This paper reports a study of a novel low-cost LFT technology and resulting composites. A patented powder-coating machine able to produce continuously pre-impregnated materials directly from fibre rovings and polymer powders was used to process glass-fibre reinforced polypropylene (GF/PP) towpregs. Such pre-impregnated materials were then chopped and used to make LFTs in a patented low-cost piston-blender developed by the Centre of Lightweight Structures, TUD-TNO, the Netherlands. The work allowed studying the most relevant towpreg production parameters and establishing the processing window needed to obtain a good quality GF/PP powder coated material. Finally, the processing window that allows producing LFTs of good quality in the piston-blender and the mechanical properties of final stamped GF/PP composite parts were also determined.

Mycotoxin contamination of Maize and Guinea corn from markets in Plateau State, Nigeria

Maize (Zea mays) and guinea corn (Sorghum bicolor) are major food items in Plateau state, Nigeria. A multistage sampling technique was used to select the markets and store/warehouses used for this study; sample collection employed a simple random sampling method from different sampling points within designated areas. A total of 18 representative samples were collected and analyzed for the following mycotoxins: aflatoxins (Aflatoxin B1 - AFB1, Aflatoxin B2 - AFB2, Aflatoxin G1 - AFG1 and Aflatoxin G2 - AFG2), fumonisins (Fumonisin B1 - FB1 and Fumonisin B2 - FB2 ) and cyclopiazonic acid (CPA). Out of 12 samples analyzed for Aflatoxins, AFB1 was detected in 5, AFB2 in 1, AFG1 in 1 and AFG2 in 6 samples respectively. The highest concentration of AFB1 and AFG2 were found in maize samples from Pankshin market. Only maize samples from Mangu market were contaminated with AFB2 and also harboured the lowest concentration of AFG2. AFG1 contamination occurred in only guinea corn from Shendam market. and FB1 was detected in all 18 samples analyzed. The mycotoxin CPA was not detected in any of the samples. Aflatoxins levels in analyzed samples were regarded as safe based on Nigerian and European Union maximum permissible levels of 4g/kg. With the exception of two samples, FB1 levels in analyzed maize samples were within European Union maximum permissible levels of 1,000 to 3000g/kg. The health and food safety implications of these results for the human and animal population are further discussed.

Consumption, wealth, stock and housing returns: evidence from emerging markets

We test the predictive ability of the transitory deviations of consumption from its common trend with aggregate wealth and labour income, cay, for both future equity and housing risk premia in emerging market economies. Using quarterly data for 31 markets, our country-level evidence shows that forecasting power of cay vis-à-vis stock returns is high for Brazil, China, Colombia, Israel, Korea, Latvia and Malaysia. As for housing returns, the empirical evidence suggests that financial and housing assets are perceived as complements in the case of Chile, Russia, South Africa and Thailand, and as substitutes in Argentina, Brazil, Hong Kong, Indonesia, Korea, Malaysia, Mexico and Taiwan. Using a panel econometric framework, we find that the cross-country heterogeneity observed in asset return predictability does not accrue to regional location, but can be attributed to differences in the degree of equity market development and in the level of income.

Simultaneous detection of cyclopiazonic acid and aflatoxin B1 by HPLC in methanol/water mobile phase

A simple procedure for the simultaneous detection of cyclopiazonic acid (CPA) and aflatoxin B1 from fungal extracts is presented, using a methanol and water mobile phase and fluorescence detection. This methodology has been tested with standard solutions of both mycotoxins CPA and Aflatoxin B1 and with methanolic extracts of Aspergillus section Flavi strains, previously characterized for their mycotoxin production profile. Previously available methodology required the use of two different chromatographic runs for these mycotoxins, with distinct columns and detectors (fluorescence detection with a post-column photochemical derivatization (PHRED) for aflatoxin B1 and UV detection for CPA). The proposed method detects both mycotoxins in a single run. Data from these assays will be presented and discussed.

Desarrollo de interfases con transferencia controlada de especies moviles. Síntesis, caracterizacion y aplicaciones. Development of Interphases with Controlled Transference of Mobile Species. Synthesis, Characterization and Applications.

Se propone sintetizar nuevos materiales como bloques de construcción de estructuras en escala nanometrica o micrométrica: nanotubos de carbono funcionalizados; nanopartículas metálicas; hidrogeles inteligentes; carbones mesoporosos. Con ellos se construiran interfaces solido/liquido estructuradas: multicapas autoensambladas, patrones micrométricos con heterogeneidad tridimensional y estructuras jerárquicas. Se estudiara el intercambio de especies móviles en las interfaces usando técnicas electroquímicas, espectroelectroquimicas, ópticas y de microscopia. De esta manera se podran controlar el intercambio en esa interface. En base a este conocimientos se desarrollaran aplicaciones tecnológicas tales como sensores de oligonucletidos, microceldas de combustible, arreglos de microelectrodos y supercapacitores.

Mercados emergentes en el escenario africano: oportunidades y desafíos para la política exterior argentina. Emergent markets in the African scene: opportunities and challenges for the Argentine foreign policy.

Este trabajo parte de la inquietud de cómo organizar y articular los recursos diplomáticos, económicos, tecnológicos y culturales que cuenta la Argentina en África, para incentivar e incrementar las vinculaciones entre ambas regiones. Teniendo en cuenta los nuevos escenarios emergentes del espacio africano y los lineamientos de política exterior ensayados por nuestro país en los últimos años, nuestro período de análisis se concentrará entre los años 2002 y 2007. Sostenemos que el desarrollo de una estrategia articulada y permanente hacia el África requiere un aprovechamiento más eficaz y eficiente de los recursos humanos, financieros y tecnológicos existentes. De esto modo, la Argentina podría posicionarse como un socio relevante en la agenda de los países africanos, proveyendo productos, tecnología y servicios a mercados complementarios y en expansión. El objetivo general del proyecto es reconocer las transformaciones recientes del diseño exterior argentino hacia los mercados emergentes, en particular hacia África.El abordaje de esta investigación tiene características tanto cualitativas como cuantitativas, al tiempo que pretende alcanzar un nivel de explicación debido al tipo de propuesta. Nuestras unidades de observación son aquellas instituciones y personalidades vinculadas a la elaboración e implementación de la política exterior de Argentina hacia los estados africanos en su conjunto (tanto de África Subsahariana como de África del Norte). En cuanto a las técnicas aplicadas se pueden reconocer diversas fases. En primera instancia se llevará adelante una exploración documental en la Cancillería argentina destinada a cubrir los principales lineamientos respecto al tema. Luego se revisarán documentos producidos por organismos privados y por investigadores científicos. Al mismo tiempo se realizarán entrevistas semiestructuradas a los actores claves que participaron en el proceso de toma de decisiones.Con este trabajo nos proponemos concretar un manual que contenga de forma sistemática las normativas y las prácticas que ejercen cada uno de los actores, tanto públicos como privados, en torno a las vinculaciones entre Argentina y los países de África. Este ordenamiento nos permitirá ofrecer a los responsables de tomas de decisiones un marco articulado, accesible y didáctico para el diseño y la ejecución de futuras políticas hacia la región. Actualmente, los lazos políticos, culturales y de cooperación entre los países de ambas regiones manifiestan un creciente dinamismo, poniendo en juego nuevos terrenos de colaboración como las Cumbres América del Sur-África, las reuniones inter-ministeriales, la firma de acuerdos de comercio entre el Mercosur y algunos estados africanos, entre otros. Sin embargo a pesar de estas señales auspiciosas, los mercados africanos no han sido explorados con la suficiente constancia y profundidad. El desarrollo de este proyecto permitirá, en primer lugar, constituir un corpus de información sobre las normativas y las prácticas en torno los vínculos argentino-africanos. Por otro lado, será una herramienta indispensable para la planificación y concreción de futuras políticas en torno al área. Cabe aclarar que no se limita a organismos del Estado sino también involucraría a actores privados implicados o interesados con los mercados emergentes africanos.

Analisis De Mercados De Energía Eléctrica Competitivos Con Participación De Energía Eólica. Competitive Electricity Markets Analisis with Wind Power Generation.

La utilización de energía eólica es un hecho cada vez más común en nuestro mundo como respuesta a mitigar el creciente aumento de demanda de energía, los aumentos constantes de precio, la escasez de combustibles fósiles y los impactos del cambio climático, los que son cada día más evidentes.Consecuentemente, el interés por la participación de esta nueva forma de generación de energía en sistema eléctrico de potencia ha aumentado considerablemente en los últimos años. La incorporación de generación de origen eólico en el sistema eléctrico de potencia requiere de un análisis detallado del sistema eléctrico en su conjunto, considerando la interacción entre parques y unidades de generación eólica, plantas de generación convencional y el sistema eléctrico de potencia. La integración de generación de origen renovable en el sistema eléctrico de potencia convencional presenta nuevos desafíos los que pueden ser atribuidos a características propias de este tipo de generación, por ejemplo la fluctuación de energía debido a la naturaleza variable del viento, la naturaleza distribuida de la generación eólica y las características constructivas y método de conexión de los distintos modelos de turbinas eólicas al sistema.La finalidad de este proyecto de investigación consiste en investigar el impacto sobre un mercado de sistema eléctrico competitivo causado por el agregado de generación de origen eolico. Como punto de partida se pretende realizar modelos de plantas de generacion eolica para luego incorporarlos a los modelos de sistemas eléctricos y realizar estudios de de despacho económico, flujo de cargas, análisis transitorio y estudios dinámicos del sistema.

middleware for cooperating mobile embedded systems

Mobile embedded systems, wireless communication, real-time systems, real-time scheduling, communication protocols, cooperation, reliability and fault-tolerance, middleware

Gradient injection in preparative chromatography : exploitation of sample solvents different than the mobile phase

Magdeburg, Univ., Fak. für Verfahrens- und Systemtechnik, Diss., 2010