346 research outputs found
A refraction/wide-angle reflection seismic profile through the Iberian Chain: preliminary report
As a result of the Eurasian and African plates convergence, Tertiary intraplate deformation of the Iberian plate gave rise to the basement-involved thrust-system of the Iberian Chain. Subsequently, a crustal thickening beneath the Iberian Chain was produced, as deduced from Bouguer anomaly maps. A very preliminary interpretation of a new seismic profile through the Iberian Chain is presented, which leads us to infer a crustal thickening beneath the central part of the profile, where Moho depths of at least 40 km should be reached
Comparative analysis of two operational amplifier topologies for a 40MS/s 12-bit pipelined ADC in 0.35μm CMOS
This paper describes a comparative analysis between two topologies of operational amplifiers to design a 40 MS/s 12-bit pipeline analog to digital converter (ADC). The analysis includes AC and transient simulation to select the proper topology. This ADC is implemented in a 0.35 mum AMS CMOS technology with 3.3 V single power supply. The capacitors and selected operational amplifiers were scaled for low power dissipation. All analog components of this pipeline ADC are fully differential, as there are dynamic comparators, analog multiplexers and operational amplifiers with gain boosting.This work has been partially supported by Fundación Séneca of Región de Murcia(Ref:03094/PI/05)and MEC of Spain(Ref:TIN2006-15460-C04-04)
Power reduction of a 12-bit 40-MS/s pipeline ADC exploiting partial amplifier sharing
High performance analog-to-digital converters (ADC) are essential elements for the development of high performance image sensors. These circuits need a big number of ADCs to reach the required resolution at a specified speed. Moreover, nowadays power dissipation has become a key performance to be considered in analog designs, specially in those developed for portable devices. Design of such circuits is a challenging task which requires a combination of the most advanced digital circuit, the analog expertise knowledge and an iterative design. Amplifier sharing has been a commonly used technique to reduce power dissipation in pipelined ADCs. In this paper we present a partial amplifier sharing topology of a 12 bit pipeline ADC, developed in 0.35 mum CMOS process. Its performance is compared with a conventional amplifier scaling topology and with a fully amplifier sharing one.This work has been supported by Ministerio de Educación y Ciencia of
Spain and the European Regional Development Fund of the European
Commission (FEDER) under grant TIN2006-15460-C04-04
Complexity and project management: a general overview
As projects have become more and more complex, there has been an increasing concern about the concept of project complexity.
An understanding of project complexity and how it might be managed is of significant importance for project managers because of the differences associated with decision-making and goal attainment that are related to complexity. Complexity influences project planning and control; it can hinder the clear identification of goals and objectives, it can affect the selection of an appropriate project organization form, or it can even affect project outcomes. Identifying the different concepts associated to project complexity, its main factors and characteristics, the different types of project complexity, and the main project complexity models, can be of great support in assisting the global project management community. In this paper, we give a general overview of how complexity has been investigated by the project management community and propose several ideas to address this topic in the future
FPGA synthesis of an stereo image matching architecture for autonomous mobile robots
This paper describes a hardware proposal to speed up the process of image matching in stereo vision systems like those employed by autonomous mobile robots. This proposal combines a classical window-based matching approach with a previous stage, where key points are selected from each image of the stereo pair. In this first step the key point extraction method is based on the SIFT algorithm. Thus, in the second step, the window-based matching is only applied to the set of selected key points, instead of to the whole images. For images with a 1% of key points, this method speeds up the matching four orders of magnitude. This proposal is, on the one hand, a better parallelizable architecture than the original SIFT, and on the other, a faster technique than a full image windows matching approach. The architecture has been implemented on a lower power Virtex 6 FPGA and it achieves a image matching speed above 30 fps.This work has been funded by Spanish government project TEC2015-66878-C3-2-R (MINECO/FEDER, UE)
EVALUACIÓN DEL COMPORTAMIENTO DE CUATRO VARIEDADES DE ZANAHORIA (Daucus carota L.) CULTIVADAS BAJO DOS SISTEMAS DE RIEGO.
El presente trabajo fue conducido para evaluar el comportamiento de cuatro variedades de zanahoria cultivadas bajo dos sistemas de riego. El experimento fue realizado en el campo experimental de la FCA, en Chirigüelo, distante a 20 km de la ciudad de Pedro Juan Caballero. El delineamiento experimental fue en bloques completamente al azar en serie de experimentos, con cuatro repeticiones. La unidad experimental se compuso de 3,0m2 sembrada a 0,3m entre hileras y 0,05m entre plantas, las que recibieron 7mm.día-1 de agua en el sistema por goteo y 1,67mm.día-1 en la convencional, en aplicaciones diarias. El experimento fue evaluado a los 114 días después de la siembra, no detectándose diferencias significativas entre las variedades, mientras que entre los sistemas de riego hubo diferencias altamente significativas en todas las variables, siendo comparadas por el test de Tukey a 5% de probabilidad. La «Kuroda» fue la de mayor rendimiento con 28,87 t.ha-1 y 13,40 t.ha-1 bajo riego por goteo y convencional, respectivamente. La «Brasilia» presentó el mejor diámetro basal y diámetro medio con 26,14mm y 24,77 mm respectivamente, además de la mayor longitud media de raíz con 12,22cm. En relación al peso promedio la «Nantes» fue la mejor con 52,06g. En todas las variables los cuatro cultivares presentaron mejor comportamiento cuando cultivados bajo el sistema de riego por goteo en relación al riego convencional
Joint implementation of the sharing OTA and bias current regulation techniques in a 11-bit 10 MS/s pipelined ADC
The power dissipation of a pipeline analog to digital converter (ADC) depends on different design
strategies. In this brief communication, an 11-bit pipeline ADC consisting of five stages with 2.5
effective bit resolution is described. The circuit combines two main techniques to improve power
dissipation, such as sharing OTAs between adjacent ADC stages and dynamic regulation of the OTA
biasing according to the stage and subcycle of operation. To reduce the charge injection effect caused
by the OTA sharing added circuitry, the ADC uses a topology based on four-input OTAs to reduce
the number of transmission gates. The ADC has been fabricated using a standard 0.35 µm CMOS
process. It consumes 17.85 mW at 10 MSample/s sampling rate. With this resolution and sampling
rate, the measurement results show that it achieves 58.20 dB SNDR and 9.38 bit ENOB at 1 MHz
input frequency.This work has been partially funded by Spanish Ministerio de Ciencia e Innovaci´on (MCI), Agencia Estatal de
Investigaci´on (AEI) and European Region Development Fund (ERDF/FEDER) under grant RTI2018-097088-BC3
El efecto de la estructura de propiedad en las participaciones en empresas de las entidades bancarias
El trabajo que se presenta analiza el efecto de la estructura de propiedad sobre la decisión de toma de
participaciones permanentes en empresas por parte de las entidades bancarias, partiendo de la
literatura del control corporativo. Concretamente, analiza el efecto de la distinta forma jurídica
existente entre bancos y cajas de ahorros, así como la pertenencia de un banco a un grupo y el carácter
doméstico o extranjero del mismo. Los resultados obtenidos para un panel de 106 entidades bancarias
en el período 1996-2001, apuntan en primer lugar, que la distinta forma jurídica entre bancos y cajas
incide en el volumen de participaciones mantenido por las entidades. En segundo lugar, para el
colectivo de bancos, si bien la pertenencia a un grupo por si sola, no parece tener relación con esta
actividad bancaria, el carácter nacional o extranjero del mismo, si presenta un efecto significativo en el
volumen de participaciones.This work, after a review of the literature on corporate control, analyzes the effect of the ownership
structure on the decisions of banking entities to take equity in firms. To be specific, it analyzes the
effect of the banks’ and savings banks’ different forms of corporation, as well as the effect of the bank
belonging to a group, and of the domestic or foreign character of the bank. The results obtained for a
panel of 106 banking entities in the 1996-2001 period indicate that the different forms of corporation
of the banks and savings banks has an effect on the amount of equity held by the entities. Moreover, in
the case of banks, whether they belong to a group or are independent does not appear to influence the
activity of holding equity, while the domestic or foreign character of the bank does have a significant
effect on the amount of equity held
- …