1,209 research outputs found

    Diet of Common buzzard (Buteo buteo) (Linnaeus, 1758) in an area of Northwestern Spain as assessed by direct observation from blinds

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    Accuracy of raptor diet assessments can vary depending on the technique employed. In the available studies in Spain, the Common buzzard (Buteo buteo) shows a diverse and non-specialized diet, reflecting local and seasonal variation in the prey availability. This study reports information on the diet of the Common buzzard in an area of Northwestern Spain, on the basis of direct observation during 308 h. of four nests from blinds. The delivery prey rate to the nest was of 0.49 ± 0.04 items per hour. From a total of 145 prey delivered to the nests, 64.7% could be determined to the taxonomic level of class, 34.5% to the levels of species, genus or suborder and a 34.5% were undetermined prey items. Mammals and reptiles were the most frequent preys in their diet, while amphibians and birds were much less frequent. These results obtained are in agreement with those from previous studies carried out in the North of Spain based on other assessments raptor diet techniques

    Multiport Multiband Decoupling Optimization for Miniature Antennas

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    Multiband multiport antennas are increasingly used for wireless communications and sensing miniature devices. The equations governing the multiport multiband antennas are analyzed in this paper with the objective of drawing the design guidelines for low coupling small antennas. Those guidelines have been applied in the design and optimization of a two-port dual band small antenna of size around λ0/13 x λ0/13 at the lowest frequency. Certain coupling conditions are applied to the port loads achieving a coupling reduction of 8 dB when having a simple two-element real load. A reduction of 27 dB can be obtained when having ideal loads composed by a higher number of elements. The antenna geometry is shown together with coupling minimization results

    Smart Beam Management for Vehicular Networks Using ML

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    [EN] The mmWave frequencies will be widely used in future vehicular communications. At these frequencies, the radio channel becomes much more vulnerable to slight changes in the environment like motions of the device, reflections or blockage. In high mobility vehicular communications the rapidly changing vehicle environments and the large overheads due to frequent beam training are the critical disadvantages in developing these systems at mmWave frequencies. Hence, smart beam management procedures are desired to establish and maintain the radio channels. In this paper, we propose that using the positions and respective velocities of the vehicles in the dynamic selection of the beam pair, and then adapting to the changing environments using ML algorithms, can improve both network performance and communication stability in high mobility vehicular communications.This work was supported by the Spanish Comision Interministerial de Ciencia y Tecnologia (CICYT) under projects TEC2016-78028-C3-1-P and MDM2016-O6OO, Catalan Research Group 2017 SGR 21, and Industrial Doctorate programme (2018-DI-084) of Generalitat de Catalunya.Bharath-Reddy, G.; Montero, L.; Perez-Romero, J.; Molins-Benlliure, J.; Ferrando Bataller, M.; Molina, J.; Romeu, J.... (2021). Smart Beam Management for Vehicular Networks Using ML. Íñigo Cuiñas Gómez. 1-4. http://hdl.handle.net/10251/1910661

    Vehicular mm-Wave Array for Smart Handover

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    [EN] The emergence of new technologies such as autonomous vehicles and high data rate 5G networks requires advanced antenna types that are capable of fulfilling requirements for highly demanding wireless communication links. The array of microstrip-fed slot-coupled patches is one such type of antenna that provides low return loss and good transient behaviour for broadband applications. A compact size slot-coupled patch antenna subarray and its phased array is proposed in this paper. Two different substrates Rogers TMM4 and Green TapeTM 951 Low Temperature Co-Fired Ceramic (LTCC) are considered for the fabrication of microstrip feedline. The feedline is fabricated on the respective substrates and then mounted on a Rogers RT/duroid 5880 laminate. Ground planes are used on both the front and backside of the antenna array. The antenna is operating in a range of 24.25 GHz - 29.5 GHz. A Smart Array is proposed in this paper which has a good performance in terms of antenna gain and scanning property for 5G application in Smart handovers.This work was partly funded by the Ministerio de Ciencia e Innovacion (MICINN) under projects TEC2016-78028-C3-1- P, PID 2019-107885GB-C31, MDM2016-0600, and Catalan Research Group 2017 SGR 219.Bharath Reddy, G.; Ramirez, GA.; Molins-Benlliure, J.; Ferrando Bataller, M.; Romeu, J.; Jofre-R., L. (2020). Vehicular mm-Wave Array for Smart Handover. Universidad de Málaga. 1-4. http://hdl.handle.net/10251/178564S1

    Private Financing or Not, That is the Question: Lessons from the Light Rail Systems in Spain

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    The objective of this paper is to analyze if there is any difference between the light rail systems in Spain according to whether they have been carried out through public financing or private financing (totally or partially). The importance of this study lies in the fact that, for decades, the public–private partnership has been proposed as an alternative to public financing of public transport projects in order to obtain additional financial resources, reduce the public deficit, and increase efficiency. However, there are hardly any detailed studies describing how these initiatives have turned out. Therefore, the present study analyzes if there is any difference in the main variables explaining the performance of light rail projects in Spain depending on their source of funding can be found. For this, the relationship between variables related to design, operation and costs of the projects, and the percentage of private financing were statistically analyzed. As the most relevant conclusion, we underline the fact that the investment per passenger increases when financing is completely private. This would indicate that the most cost-effective lines, from a social standpoint, were financed totally or partially by the public administrations, whereas the least beneficial ones for society were assigned to private enterprises. This finding provides an advance in the knowledge of the consequences of private participation in the financing of public transport projects, indicating, moreover, that the biggest beneficiaries of this type of projects might be the construction companies and the politicians involvedThe authors would like to thank the ERDF of European Union for financial support via project ‘‘Herramienta para la evaluacio´n previa de infraestructuras de transporte pu´blico’’ (GGI3003IDIE). We also thank to Public Works Agency and Regional Ministry of Public Works and Housing of the Regional Government of Andalusia (AOPJA) and the Ministry of Education, Culture and Sports of the Government of Spain

    Three dimensional microfabricated broadband patch and multifunction reconfigurable antennae for 60 GHz applications

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    In this paper we present two antenna designs capable of covering the IEEE 802.11ad (WiGig) frequency band (57-66 GHz and 59-66 GHz respectively). The work below reports the design, microfabrication and characterization of a broadband patch antenna along with the design and microfabrication of multifunction reconfigurable antenna (MRA) in its static form excluding active switching. The first design is a patch antenna where the energy is coupled with a conductor-backed (CB) coplanar waveguide (CPW)-fed loop slot, resulting in a broad bandwidth. The feed circuitry along with the loop is formed on a quartz substrate (at 60 GHz), on top of which an SU-8-based three-dimensional (3D) structure with air cavities is microfabricated. The patch metallization is deposited on top of this structure. The second design is a CB CPW-fed loop slot coupled patch antenna with a parasitic layer on top. The feed circuitry along with the loop is formed on a quartz substrate. On top, the patch metallization is patterned on another quartz substrate. The parasitic pixels are deposited on top of these two quartz layers on top of an SU-8 based 3D structure with air cavities. © 2015 EurAAP

    Three-dimensional microfabricated broadband patch antenna for wigig applications

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    The design, microfabrication, and characterization of a broadband patch antenna capable of covering the entire IEEE 802.11ad (WiGig) frequency band (57-66 GHz) are presented in this letter. A conductor-backed (CB) coplanar waveguide (CPW)-fed loop slot couples the energy to the patch antenna, resulting in a broad bandwidth. The feed circuitry along with the loop is formed on a quartz substrate (\varepsilon-{\rm r} = 3.9, \tan \delta = 0.0002 at 60 GHz), on top of which an SU-8-based three-dimensional (3-D) structure with air cavities is microfabricated. The patch metallization is deposited on top of this 3-D structure. While the main role of the structure made out of SU-8 material is to provide a mechanical support for the patch metallization, the antenna takes advantage of the air cavities underneath, thus resulting in an antenna substrate with a very low loss. This, in turn, improves the overall antenna performances. The simulated and measured impedance characteristics agree well, showing {\sim}15\hbox{\%} bandwidth. Also, the radiation pattern results demonstrate the integrity of radiation pattern with reasonably constant gain values (average {\sim}6.4~dB) in the broadside direction over the entire WiGig band. © 2002-2011 IEEE

    Judicial disagreement need not be political: dissent on the Estonian Supreme Court

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    I investigate the non-unanimous decisions of judges on the Estonian Supreme Court. I argue that since judges on the court enjoy high de jure independence, dissent frequently, and are integrated in the normal judicial hierarchy, the Estonian Supreme Court is a crucial case for the presumption that judicial disagreement reveals policy preferences. I analyse dissenting opinions using an ideal point response model. Examining the characteristics of cases which discriminated with respect to the recovered dimension, I show that this dimension cannot be interpreted as a meaningful policy dimension, but instead reflects disagreement about the proper scope of constitutional redress
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