906 resultados para ad-hoc array, microphone array, beamforming, array calibration, blind speech separation, speech enhancement, automatic speech recognition


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The last few years have seen a substantial increase in the geometric complexity for 3D flow simulation. In this paper we describe the challenges in generating computation grids for 3D aerospace configuations and demonstrate the progress made to eventually achieve a push button technology for CAD to visualized flow. Special emphasis is given to the interfacing from the grid generator to the flow solver by semi-automatic generation of boundary conditions during the grid generation process. In this regard, once a grid has been generated, push button technology of most commercial flow solvers has been achieved. This will be demonstrated by the ad hoc simulation for the Hopper configuration.

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This paper describes a protocol for dynamically configuring wireless sensor nodes into logical clusters. The concept is to be able to inject an overlay configuration into an ad-hoc network of sensor nodes or similar devices, and have the network configure itself organically. The devices are arbitrarily deployed and have initially have no information whatsoever concerning physical location, topology, density or neighbourhood. The Emergent Cluster Overlay (ECO) protocol is totally self-configuring and has several novel features, including nodes self-determining their mobility based on patterns of neighbour discovery, and that the target cluster size is specified externally (by the sensor network application) and is not directly coupled to radio communication range or node packing density. Cluster head nodes are automatically assigned as part of the cluster configuration process, at no additional cost. ECO is ideally suited to applications of wireless sensor networks in which localized groups of sensors act cooperatively to provide a service. This includes situations where service dilution is used (dynamically identifying redundant nodes to conserve their resources).

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Food insecurity, chronic hunger, starvation and malnutrition continue to affect millions of individuals throughout the developing world, especially Sub-Saharan Africa. Various initiatives by African governments and International Agencies such as the UN, the industrial nations, the International Monetary Fund, the World Bank and the World Trade Organisation to boost economic development, have failed to provide the much-needed solution to these challenges. The impact of these economic shifts and the failures of structural adjustment programmes on the nutritional well-being and health of the most vulnerable members of poor communities cannot be over-emphasised. The use of ad hoc measures as an adjunct to community-based rural integrated projects have provided little success and will be unsustainable unless they are linked to harnessing available local resources. The present paper therefore focuses on exploring alternative ways of harnessing the scant agricultural resources by employing a scientific approach to food-related problem-solving. The food multimix (FMM) concept offers a scientific contribution alongside other attempts currently in use by the World Food Programme, WHO and FAO to meet the food insecurity challenges that confront most of the developing world in the twenty-first century. It is an innovative approach that makes better use of traditional food sources as a tool for meeting community nutritional needs. The FMM concept employs a food-based approach using traditional methods of food preparation and locally-available, cheap and affordable staples (fruits, pulses, vegetables and legumes) in the formulation of nutrient-enriched multimixes. Developed recipes can provide >= 40% of the daily nutritional requirements of vulnerable groups, including patients with HIV/AIDS and children undergoing nutrition rehabilitation. The FMM approach can also be used as a medium- to long-term adjunct to community-based rural integration projects aimed at health improvement and economic empowerment in Sub-Saharan Africa.

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1. A first step in the analysis of complex movement data often involves discretisation of the path into a series of step-lengths and turns, for example in the analysis of specialised random walks, such as Lévy flights. However, the identification of turning points, and therefore step-lengths, in a tortuous path is dependent on ad-hoc parameter choices. Consequently, studies testing for movement patterns in these data, such as Lévy flights, have generated debate. However, studies focusing on one-dimensional (1D) data, as in the vertical displacements of marine pelagic predators, where turning points can be identified unambiguously have provided strong support for Lévy flight movement patterns. 2. Here, we investigate how step-length distributions in 3D movement patterns would be interpreted by tags recording in 1D (i.e. depth) and demonstrate the dimensional symmetry previously shown mathematically for Lévy-flight movements. We test the veracity of this symmetry by simulating several measurement errors common in empirical datasets and find Lévy patterns and exponents to be robust to low-quality movement data. 3. We then consider exponential and composite Brownian random walks and show that these also project into 1D with sufficient symmetry to be clearly identifiable as such. 4. By extending the symmetry paradigm, we propose a new methodology for step-length identification in 2D or 3D movement data. The methodology is successfully demonstrated in a re-analysis of wandering albatross Global Positioning System (GPS) location data previously analysed using a complex methodology to determine bird-landing locations as turning points in a Lévy walk. For this high-resolution GPS data, we show that there is strong evidence for albatross foraging patterns approximated by truncated Lévy flights spanning over 3·5 orders of magnitude. 5. Our simple methodology and freely available software can be used with any 2D or 3D movement data at any scale or resolution and are robust to common empirical measurement errors. The method should find wide applicability in the field of movement ecology spanning the study of motile cells to humans.

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Three different worlds, sometimes concentric and often intersecting —society, theatre and the art of performance— and social work. Diverse worlds that live, reflect and self-reflect and interact, and can also afford an opportunity for meeting, misunderstanding and confrontation, and above all offer the possibility of profound change.This article considers the experience of a theatre company that has spent more than three years moving at the limits of these three universes. To these three worlds can be added an infinite number of words that fill them with meaning and significance: territory, meeting, diversity and search. An artistic experience that has chosen to focus on creating scenarios for debate and to examine the difficulties, the human contradictions and the constant and inexhaustible confrontation with human experience. At the heart of this theatrical activity is all of this, seeking the balance between narration, meeting, investigation and the artistic dimension. This meeting between society, theatre and social work also contains the search for sustainability of this cultural business, in an Italy that has been destroyed by a crisis that is not merely economic, but also of values and, above all, of role models. The guiding theme, though not always made explicit, is always present and essential: the search for beauty.

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Closing feedback loops using an IEEE 802.11b ad hoc wireless communication network incurs many challenges sensitivity to varying channel conditions and lower physical transmission rates tend to limit the bandwidth of the communication channel. Given that the bandwidth usage and control performance are linked, a method of adapting the sampling interval based on an 'a priori', static sampling policy has been proposed and, more significantly, assuring stability in the mean square sense using discrete-time Markov jump linear system theory. Practical issues including current limitations of the 802.11 b protocol, the sampling policy and stability are highlighted. Simulation results on a cart-mounted inverted pendulum show that closed-loop stability can be improved using sample rate adaptation and that the control design criteria can be met in the presence of channel errors and severe channel contention.

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Transparency in nonprofit sector and foundations, as an element to enhance the confidence of stakeholders in the organization, is a fact shown by several studies in recent decades. Transparency can be considered in various fields and through different channels. In our study we focused on the analysis of the organizational and economic transparency of foundations, shown through the voluntary information on their Website. We review the theoretical previous studies published to put to the foundations within the framework of the social economy. This theoretical framework has focused on accountability that make foundations in relation to its social function and its management, especially since the most recent focus of information transparency across the Website.In this theoretical framework was made an index to quantify the voluntary information which is shown on its website. This index has been developed ad hoc for this study and applied to a group of large corporate foundations.With the application of these data are obtained two kind of results, to a descriptive level and to a inferential level.We analyzed the statistical correlation between economic transparency and organizational transparency offered in the Website through quantified variables by a multiple linear regression. This empirical analysis allows us to draw conclusions about the level of transparency offered by these organizations in relation to their organizational and financial information, as well as explain the relation between them.

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This work aims to analyze the perceptions of students enrolled in the Master's Degree in Secondary Education Teaching, Training and Language Teaching at the University of Jaen, about the initial training received on attention to diversity. A descriptive methodology has been followed using an ad hoc questionnaire as data collection instrument. The results show favorable attitudes of future secondary teachers for diversity, having received an adequate training in curricular and organizational aspects, making it able to fully achieve inclusion of students with special educational needs in the classroom.

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La Educación para la Salud (EpS) es un tema transversal del currículo que adolece de propuestas didácticas novedosas para la intervención pedagógica. El objetivo del trabajo que se presenta es poner en marcha un plan de mejora para la prevención de drogadicciones en adolescentes. Para ello, se ha trabajado con un total de 142 estudiantes de 3º de Educación Secundaria Obligatoria (ESO) con edades comprendidas entre los 14 y los 16 años que cursan estudios en el Instituto “Francisco Salzillo” de la localidad de Alcantarilla (Murcia). Concretamente, este artículo da luz al Proyecto ¡Abre los ojos!, que forma parte del Plan de Acción Tutorial (PAT) y del Plan de Mejora para la Prevención de Drogas (PMPD) propuesto desde el Departamento de Orientación. Se exponen ad hoc las actividades implementadas durante las 3 sesiones trabajadas con cada uno de los 6 grupos-clase escolarizados en este nivel. Haciendo uso de la reflexión-acción, el alumnado ha desarrollado una conciencia crítica acerca de los riesgos que entraña para la salud el consumo de drogas. Asimismo, mediante la técnica de grupos de discusión los discentes han realizado un interesante debate cuyas ideas han sido organizadas en torno a tres aspectos clave: causas por las que se empieza a consumir, cómo evitar caer en las drogas, y alternativas de ocio y tiempo libre para una vida saludable. Finalmente, se especifica la necesidad de abordar tareas de prevención en los centros educativos así como de facilitar información y de resolver las inquietudes de los jóvenes acerca de esta temática.

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Students' learning process can be negatively affected when their reading and comprehension control is not appropriated. This research focuses on the analysis of how a group of students from high school evaluate their reading comprehension in manipulated scientific texts. An analysis tool was designed to determine the students' degree of comprehension control when reading a scientific short text with an added contradiction. The results have revealed that the students from 1st and 3rd ESO do not properly self-evaluated their reading comprehension. A different behavior has been observed in 1st Bachillerato, where appropriate evaluation and regulation seem to be more frequent. Moreover, no significant differences have been found regarding the type of text, year or gender. Finally, as identified by previous research, the correlations between the students' comprehension control and their school marks have shown to have a weak relationship and inversely proportional to the students' age.

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Los avances que están produciéndose en el ámbito académico con el surgimiento de herramientas de la Web 2.0 y el empleo masivo por parte de los estudiantes de la redes sociales para comunicarse entre ellos, está haciendo que el panorama educativo se encuentre ante unos desafíos a los que tiene que dar respuesta. La investigación que aquí se presenta tuvo como objetivo principal analizar el estado del empleo de la redes sociales por parte alumnado universitario, así como los posibles malos hábitos y usos problemáticos de las mismas. Se utilizó como instrumento de recogida de información un cuestionario “ad hoc” con un total de 23 ítems. Se concluye que el alumnado en general no posee malos hábitos en el empleo de las redes sociales, igualmente los resultados obtenidos ponen de manifiesto que su utilización no está plenamente integrada en las instituciones universitarias de educación superior, así como que los estudiantes no las emplean/usan como herramienta fundamental para las resolución de cuestiones académicas.

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Background: Infection remains a severe complication following a total hip replacement. If infection is suspected when revision surgery is being performed, additional gentamicin is often added to the cement on an ad hoc basis in an attempt to reduce the risk of recurrent infection.

Methods and results: In this in vitro study, we determined the effect of incorporating additional gentamicin on the mechanical properties of cement. We also determined the degree of gentamicin release from cement, and also the extent to which biofilms of clinical Staphylococcus spp. isolates form on cement in vitro. When gentamicin was added to unloaded cement (1–4 g), there was a significant reduction in the mechanical performance of the loaded cements compared to unloaded cement. A significant increase in gentamicin release from the cement over 72 h was apparent, with the amount of gentamicin released increasing significantly with each additional 1 g of gentamicin added. When overt infection was modeled, the incorporation of additional gentamicin did result in an initial reduction in bacterial colonization, but this beneficial effect was no longer apparent by 72 h, with the clinical strains forming biofilms on the cements despite the release of high levels of gentamicin.

Interpretation: Our findings indicate that the addition of large amounts of gentamicin to cement is unlikely to eradicate bacteria present as a result of an overt infection of an existing implant, and could result in failure of the prosthetic joint because of a reduction in mechanical performance of the bone cement.

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This study highlights how heuristic evaluation as a usability evaluation method can feed into current building design practice to conform to universal design principles. It provides a definition of universal usability that is applicable to an architectural design context. It takes the seven universal design principles as a set of heuristics and applies an iterative sequence of heuristic evaluation in a shopping mall, aiming to achieve a cost-effective evaluation process. The evaluation was composed of three consecutive sessions. First, five evaluators from different professions were interviewed regarding the construction drawings in terms of universal design principles. Then, each evaluator was asked to perform the predefined task scenarios. In subsequent interviews, the evaluators were asked to re-analyze the construction drawings. The results showed that heuristic evaluation could successfully integrate universal usability into current building design practice in two ways: (i) it promoted an iterative evaluation process combined with multi-sessions rather than relying on one evaluator and on one evaluation session to find the maximum number of usability problems, and (ii) it highlighted the necessity of an interdisciplinary ad hoc committee regarding the heuristic abilities of each profession. A multi-session and interdisciplinary heuristic evaluation method can save both the project budget and the required time, while ensuring a reduced error rate for the universal usage of the built environments.

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The government of Greece has gained notoriety for its failure to implement EU environmental directives in general, and is criticised specifically for its lack of an effective plan for the safe disposal of waste. Local mobilisations against a series of planned 'Sanitary Waste Disposal Sites' (HETAs) in three municipalities of Attica are examined. Should such protests be classified as NIMBY (not in my backyard)? Or do they present broader claims of justice and equity? Qualitative analysis of the protesters' on-line campaign material reveals that while these mobilisations do demonstrate some NIMBY characteristics, such campaigns should rather be perceived as ad hoc mobilisations reflective of tensions of late modernity. The public's mistrust of science and concerns about democratic deficit and accountability, as well as different perceptions of risk, are prominent.

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Mobile ad hoc networking of dismounted combat personnel is expected to play an important role in the future of network-centric operations. High-speed, short-range, soldier-to-soldier wireless communications will be required to relay information on situational awareness, tactical instructions, and covert surveillance related data during special operations reconnaissance and other missions. This article presents some of the work commissioned by the U. K. Ministry of Defence to assess the feasibility of using 60 GHz millimeter-wave smart antenna technology to provide covert communications capable of meeting these stringent networking needs. Recent advances in RF front-end technology, alongside physical layer transmission schemes that could be employed in millimeter-wave soldier-mounted radio, are discussed. The introduction of covert communications between soldiers will require the development of a bespoke directive medium access layer. A number of adjustments to the IEEE 802.11 distribution coordination function that will enable directional communications are suggested. The successful implementation of future smart antenna technologies and direction of arrival-based protocols will be highly dependent on thorough knowledge of transmission channel characteristics prior to deployment. A novel approach to simulating dynamic soldier-to-soldier signal propagation using state-of-the-art animation-based technology developed for computer game design is described, and important channel metrics such as root mean square angle and delay spread for a team of four networked infantry soldiers over a range of indoor and outdoor environments is reported.