A low-power reconfigurable ADC for biomedical sensor interfaces

This paper presents a 12-bit low-voltage low-power reconfigurable Analog-to-Digital Converter (ADC). The design employs Switched Capacitor (SC) techniques and implements a Successive Approximation (SA) algorithm. The ADC can be tuned to handle a large variety of biopotential signals, with digitally selectable resolution and input signal amplitude. It achieves 10.4-bit of effective resolution sampling at 56kS/s, with a power consumption below 3μW from a 1V voltage supply.Ministerio de Educación y Ciencia TEC2006-03022Junta de Andalucía TIC-0281

A 13-bit, 2.2-MS/s, 55-mW multibit cascade ΣΔ modulator in CMOS 0.7-μm single-poly technology

This paper presents a CMOS 0.7-μm ΣΔ modulator IC that achieves 13-bit dynamic range at 2.2 MS/s with an oversampling ratio of 16. It uses fully differential switched-capacitor circuits with a clock frequency of 35.2 MHz, and has a power consumption of 55 mW. Such a low oversampling ratio has been achieved through the combined usage of fourth-order filtering and multibit quantization. To guarantee stable operation for any input signal and/or initial condition, the fourth-order shaping function has been realized using a cascade architecture with three stages; the first stage is a second-order modulator, while the others are first-order modulators - referred to as a 2-1-1mb architecture. The quantizer of the last stage is 3 bits, while the other quantizers are single bit. The modulator architecture and coefficients have been optimized for reduced sensitivity to the errors in the 3-bit quantization process. Specifically, the 3-bit digital-to-analog converter tolerates 2.8% FS nonlinearity without significant degradation of the modulator performance. This makes the use of digital calibration unnecessary, which is a key point for reduced power consumption. We show that, for a given oversampling ratio and in the presence of 0.5% mismatch, the proposed modulator obtains a larger signal-to-noise-plus-distortion ratio than previous multibit cascade architectures. On the other hand, as compared to a 2-1-1single-bit modulator previously designed for a mixed-signal asymmetrical digital subscriber line modem in the same technology, the modulator in this paper obtains one more bit resolution, enhances the operating frequency by a factor of two, and reduces the power consumption by a factor of four.Comisión Interministerial de Ciencia y Tecnología TIC97-0580European Commission ESPRIT 879

Evaluation of forest industry scenarios to increase sustainable forest mobilization in regions of low biomass demand

There is an increasing interest in forest biomass for energy throughout Europe, which is seen as a way of promoting forest mobilization and economic development locally, in particular in regions where forest biomass is available but its use is limited by lack of demand. This study was conducted to define, evaluate and select viable forest industry scenarios to increasing forest mobilisation in the North of Portugal using AppTitudefi, a Forest Management Decision Support Systems (FMDSS) considering spatially explicitly supply (biomass growth and yield), demand (industry), and supply-demand interactions (markets). The protocol followed combined a set of indicators of sustainable forest management to guide the selection of the best industry solutions in terms of location, dimension, forest biomass and other variables defined as objectives. The simulations allowed the selection of a small set of industry scenarios compatible with an existing plant outside the study area, increasing wood mobilization, preventing overexploitation and competition among industries but increasing value and price of forest biomass. The results of the application of this FMDSS showed that introducing new biomass plants in the region will increase sustainable forest mobilization and related local development. AppTitudefi revealed to be a powerful and reliable tool to assist forest planning.This research was funded through the EU 7th Framework Programme for Research, Technological Development, and Demonstration (agreement no. 613762: SIMWOOD—Sustainable Innovative Mobilisation of Wood). J.C.A received partial support from Foundation for Science and Technology (FCT), Portugal through CIMO (UIDB/00690/2020). F.P_R received partial support from the Department of Economy, Industry and Competitiveness, Spanish Government, grant no. PTQ-16-08633.info:eu-repo/semantics/publishedVersio

The wage gap between immigrant and native workers in Spain: an analysis using matched employer-employee data

The fact that Spain has witnessed a sharp increase in the number of immigrants over the past decade has generated considerable interest, particularly as regards wages earned by immigrants in host industries. We analyze whether controlling for both observable and unobservable characteristics of employers —in addition to individual variables and the economic context— makes any difference as regards the debate regarding the existence of wage differences between immigrant and native workers in Spain. As we show, doing this considerably reduces (or even eliminates) the inequalities found in previous research, thereby questioning the results attained by previous studies on this issue.Immigration, salaries, assimilation.

Un punto de conexión, un punto de encuentro

Nos interesa estudiar e investigar en la conformación de un espacio físico que, destinado a la conexión e información virtual, sea un lugar de encuentro real. Nos interesa proponer desde la arquitectura lugares de confluencia de redes sociales virtuales y las redes sociales ‘materiales’ (asociaciones, vecinos, ciudadanos…). Los ciudadanos se muestran mucho más creativos en la red y sorprendentemente se inhiben en la presencia del espacio real. Cierta ‘reserva’ frente a lo público de nuestras acciones, esto es, cierto ocultamiento puede estimular creativamente el uso y disfrute del espacio arquitectónico. La tecnología de la información ha reconfigurado el individuo y sus relaciones sociales. La información ha desplegado los espacios de conexión/comunicación y ha dado profundidad/espesor al frugal tiempo cotidiano. ¿Qué lugares de encuentro de estos intangibles espacios y tiempos podemos ‘pensar’ desde la producción tangible de arquitectura? Son lugares donde deben reproponerse las relaciones entre lo colectivo y lo íntimo, la formación y la información, la comunicación y el diálogo. En contadas ocasiones la arquitectura ha propuesto un soporte para la interacción de la información y el medio. Estudiamos cómo hacer propuestas desde la arquitectura que hagan posible el flujo de personas, usuarios, visitantes, paseantes, ciudadanos que interactúen entre sí, arquitectura que albergue un software socialmente creativo. Buscamos hacer menos arquitectura para que ocurran más acontecimientos: un principio de ecología básica que haga posible la sostenibilidad integral como un objetivo constructivo, económico y social. En una situación pendular entre la exhibición, la invitación y el consumo de lo público y el ocultamiento, la intimidad y la re-creación de lo privado se sitúan las propuestas descritas en este artículo: obra construida ‘CiberCentroSocial Macarena Tres Huertas’ (Sevilla, 2010), acción reivindicativa para el ‘Concurso del logotipo para presupuestos participativos’ (Sevilla, 2004) y un ‘proyecto de investigación y denuncia de espacios vacíos’ (viviendas mayoritariamente) presentado en el ‘Foro barriadas: nuevos centros urbanos’ (Junta de Andalucía , 2006) . Pensamos que estos proyectos presentados más que un lugar, proponen un proceso donde articular nuevas formas de vecindad con agentes y espacios cercanos, así como con otros geográfica y culturalmente distantes. Son proyectos donde es más importante la ‘presencia’ (de los ciudadanos) que la ‘permanencia’ (de un edificio), donde la arquitectura, en este mundo de redes y encuentros, es, por tanto, un fenómeno ‘en tránsito’.We are interested in investigating the formation of a physical space which, devoted to virtual connexions and information, becomes a real ‘meeting point’. We want to propose through architecture the merging of ‘sites’ for both virtual and material social networks. Information Technology has re-configured the social relations of human beings. Information has opened up communication spaces, and has given depth and quality to our limited daily time. These are spaces that re-invent the relationship between collective and private spaces, formation and information, communication and dialogue. Which meeting places of these intangible spaces can be designed from the tangible production of architecture? Only on few occasions has architecture proposed a setting in which information and space can interact. This is the reason why our research is centered on architecture as the medium for multitude programmes, functions and timings: that means, being a programmable ‘hardware’. We are investigating how to propose a ‘multipotential’ space, where the flows of users and visitors may enter and where citizens may interact among others. That is architecture that holds active social ‘software’. We propose to do less architecture to allow more ‘gathering events’ to happen: a principle of basic ecology that makes integral sustainability possible as a constructive, economical and social objective. All social centres are more than a just a place, they are a process where new neighbourhood forms are articulated with ‘agents’ and ‘places’ that are nearby but also with others that are geographic and culturally more remote. We present three examples where we have proposed such processes: the already built Social Cyber Centre Macarena Tres Huertas (Seville); a competition and a participative ‘action’ for a Logo for Participative Budgets at the Seville Council; and an investigation about vacant housing presented at Foro Barriadas: new urban centres(Andalusian Goverment). We think in such places ‘presence’ (citizenry) is more important than ‘permanency’ (buildings), where architecture, in this world of networks and meeting places, is a phenomena in transit

The triangle assessment method: a new procedure for eliciting expert judgement

The Analytic Hierarchy Process (AHP) is one of the most widely used Multi-Criteria Decision-Making methods worldwide. As such, it is subject to criticisms that highlight some potential weaknesses. In this study, we present a new Multi-Criteria Decision-Making method denominated the “Triangular Assessment Method” (referred to by its Spanish abbreviation, MTC©). The MTC© aims to make use of the potential of AHP while avoiding some of its drawbacks. The main characteristics and advantages of the MTC© can be summarised as follows: (i) evaluation of criteria, and of the alternative options for each criterion, in trios instead of pairs; (ii) elimination of discrete scales and values involved in judgements; (iii) a substantial reduction in the number of evaluations (trios) relative to the corresponding number of pairs which would have to be considered when applying the AHP method; (iv) consistent decision-making; (v) introduction of closed cyclical series for comparing criteria and alternatives; and (vi) the introduction of opinion vectors and opinion surfaces. This new method is recommended for supporting decision-making with large numbers of subjective criteria and/or alternatives and also for group decisions where the consensus must be evaluated. The MTC© provides a different promising perspective in decision-making and could lead to new research lines in the field of information systems.This work was supported by the Galician Regional Government [“Programa de Consolidación e Estructuración de Unidades de Investigación Competitivas, modalidade de Grupos de Referencia Competitiva” for the period 2006–2017] and by the European Union [ERDF program]. Likewise, the authors thank Daniele de Rigo, Dora Henriques and Cesar Pérez-Cruzado, because his comments improved notably this manuscript.info:eu-repo/semantics/publishedVersio

A Triangular Assessment Method

A Triangular Assessment Method (Research in progress, abbreviated to MTC, from the initials of the Spanish name: Método del Triángulo de Calificaciones) is described. The proposed method is an improvement of the well known Analytic Hierarchy Process (AHP), which is a pairwise comparison technique developed by Saaty and often applied in complex decision making. The MTC basically consists of comparing criteria and alternative levels of each criterion in trios instead of in pairs. This overcomes some of the drawbacks of the AHP, such as the large number of pairs that must be analyzed when there are numerous criteria and alternatives