921 research outputs found

    Radiocarbon chronology of dolmens in the Iberian southwest: architectural sequence and temporality in the el Pozuelo megalithic complex (Huelva, Spain)

    Get PDF
    This paperes tablishes the chronologyof the ElPozuelo megalithic complexand discusses it in the context of other dolmens that have been dated in the southwest of the Iberian Peninsula. The working methodology combines the study of the stratigraphy and architectural sequence with the Bayesian modeling of the 27 AMS 14C dates obtained for charcoal samples from the four monuments in the Los Llanetes cluster. The most significant chronological results (at 68% probability) are (a) the antiquity and long duration of the megalithic sites, in which several monumental structures succeeded one another ca. 3970–1980 cal BC; (b) the existences of different temporalities in the LateFinal Neolithic dolmens: simple chambers (3970–3760 cal BC), elongated chambers (3790–3620 cal BC) and multiple chambers (3660–3260 cal BC; (c) the continuity of activity during the Copper Age (2980–2580 and 25302180 cal BC); and (d) the permanence of megalithism in the Early Bronze Age, through the presence of terraced enclosures with circular platforms ca. 2230–1940 cal BC. This diachronic sequence and the contextualized analysis of the 152 available radiocarbon dates (27 new, 125 published) supports the establishment of the temporal dynamics of megalithism in the Iberian southwest, introducing key aspects on the emergence, span, and rebuilding of the different dolmens (passage graves, simple chambers, elongated chambers, and multiple chambers) and establishing the phases of activity and reuse of the different architectural types.This study has been carried out within the framework of the R D i Project “MEGA-LITHOS. Geo-archaeological study methods for the investigation of the Huelva megalithisms” (UHU- 1263153) at the University of Huelva, funded by the Operative Programme ERDF 2014-2020 and the Department of Economy and Knowledge in the Government of Andalusia. The radiocarbon dates were commissioned at the CNA by the Culture Department in the Government of Andalusia within the Exceptional Archaeological Activity under our direction. The funding of the open access charge has been assumed by the University of Huelva, thanks to the agreement established with Cambridge University Press. I am grateful to Coronada Mora Molina for her invaluable participation in the excavation and research of the Los Llanetes cluster. Juan Carlos Vera-Rodríguez and Luc Laporte, supervisors of my doctoral thesis, for their guidance and observations for the investigation. M´onica Ruiz Alonso has contributed to the anthracological study of the charcoal samples. Thanks to the reviewers for their comments and suggestions, which have improved several aspects of the wor

    Análise de proveniência das contas verdes dos Perdigões

    Get PDF
    A variscite é um mineral raro que oferece uma excelente opotunidade de estudo dos padrões de comércio e troca na Europa durante a Pré- História através da determinação da sua fonte de proveniência. No presente texto será discutida a proveniência das contas de colar verdes com base em análises de XRF e XRD, através das quais se criou uma identidade geoquímica passível de ser comparada com as das fontes de variscite conhecidasVariscite is a rare mineral that offers an excellent opportunity to study trade and exchange patterns in prehistoric Europe through proveniencing of source material. In this paper we discuss the provenance of Perdigões’ green beads by means of XRF and XRD analyses, thus creating a geochemical baseline that is compared with that of the known variscite source

    Retinal ganglion cell software and FPGA model implementation for object detection and tracking

    Get PDF
    This paper describes the software and FPGA implementation of a Retinal Ganglion Cell model which detects moving objects. It is shown how this processing, in conjunction with a Dynamic Vision Sensor as its input, can be used to extrapolate information about object position. Software-wise, a system based on an array of these of RGCs has been developed in order to obtain up to two trackers. These can track objects in a scene, from a still observer, and get inhibited when saccadic camera motion happens. The entire processing takes on average 1000 ns/event. A simplified version of this mechanism, with a mean latency of 330 ns/event, at 50 MHz, has also been implemented in a Spartan6 FPGA.European Commission FP7-ICT-600954Ministerio de Economía y Competitividad TEC2012-37868-C04-02Junta de Andalucía P12-TIC-130

    Live Demonstration: Retinal ganglion cell software and FPGA implementation for object detection and tracking

    Get PDF
    This demonstration shows how object detection and tracking are possible thanks to a new implementation which takes inspiration from the visual processing of a particular type of ganglion cell in the retina

    On Real-Time AER 2-D Convolutions Hardware for Neuromorphic Spike-Based Cortical Processing

    Get PDF
    In this paper, a chip that performs real-time image convolutions with programmable kernels of arbitrary shape is presented. The chip is a first experimental prototype of reduced size to validate the implemented circuits and system level techniques. The convolution processing is based on the address–event-representation (AER) technique, which is a spike-based biologically inspired image and video representation technique that favors communication bandwidth for pixels with more information. As a first test prototype, a pixel array of 16x16 has been implemented with programmable kernel size of up to 16x16. The chip has been fabricated in a standard 0.35- m complimentary metal–oxide–semiconductor (CMOS) process. The technique also allows to process larger size images by assembling 2-D arrays of such chips. Pixel operation exploits low-power mixed analog–digital circuit techniques. Because of the low currents involved (down to nanoamperes or even picoamperes), an important amount of pixel area is devoted to mismatch calibration. The rest of the chip uses digital circuit techniques, both synchronous and asynchronous. The fabricated chip has been thoroughly tested, both at the pixel level and at the system level. Specific computer interfaces have been developed for generating AER streams from conventional computers and feeding them as inputs to the convolution chip, and for grabbing AER streams coming out of the convolution chip and storing and analyzing them on computers. Extensive experimental results are provided. At the end of this paper, we provide discussions and results on scaling up the approach for larger pixel arrays and multilayer cortical AER systems.Commission of the European Communities IST-2001-34124 (CAVIAR)Commission of the European Communities 216777 (NABAB)Ministerio de Educación y Ciencia TIC-2000-0406-P4Ministerio de Educación y Ciencia TIC-2003-08164-C03-01Ministerio de Educación y Ciencia TEC2006-11730-C03-01Junta de Andalucía TIC-141

    Efficient DMA transfers management on embedded Linux PSoC for Deep-Learning gestures recognition: Using Dynamic Vision Sensor and NullHop one-layer CNN accelerator to play RoShamBo

    Get PDF
    This demonstration shows a Dynamic Vision Sensor able to capture visual motion at a speed equivalent to a highspeed camera (20k fps). The collected visual information is presented as normalized histogram to a CNN accelerator hardware, called NullHop, that is able to process a pre-trained CNN to play Roshambo against a human. The CNN designed for this purpose consist of 5 convolutional layers and a fully connected layer. The latency for processing one histogram is 8ms. NullHop is deployed on the FPGA fabric of a PSoC from Xilinx, the Zynq 7100, which is based on a dual-core ARM computer and a Kintex-7 with 444K logic cells, integrated in the same chip. ARM computer is running Linux and a specific C++ controller is running the whole demo. This controller runs at user space in order to extract the maximum throughput thanks to an efficient use of the AXIStream, based of DMA transfers. This short delay needed to process one visual histogram, allows us to average several consecutive classification outputs. Therefore, it provides the best estimation of the symbol that the user presents to the visual sensor. This output is then mapped to present the winner symbol within the 60ms latency that the brain considers acceptable before thinking that there is a trick.Ministerio de Economía y Competitividad TEC2016-77785-

    Life and Death of the Macrolithic Tools from the Third-millennium cal. BC Necropolis of La Orden-Seminario in Southwest Spain

    Get PDF
    Macrolithic tools are linked to daily activities and, fundamentally, to settlements, hence their importance for the study of Late Prehistoric societies. However, these objects are also associated with funerary contexts, but have not often been analysed holistically. This paper studies an assemblage of macrolithic elements from three collective tombs from the third millennium cal. BC at the site of La Orden-Seminario (Huelva, Spain), from a theoretical and methodological perspective based on the biography of the object. Our analysis focuses on typology, raw materials, technology, function and burial context. The results show that the tools can be linked to domestic activities such as the grinding of cereals and the processing of plant materials, as well as for the production and maintenance of the elements used in these activities. The analysed objects display long biographies of use and, in some cases, we have documented intentional breakage for their deposition in the tombs. The patterns of deposition in the funerary contexts reflect social practices related to the ritual and symbolic behaviours surrounding death and the relationship with everyday objects.This study has been carried out within the framework of the R+D+i Project ‘MEGA-LITHOS. Geo-archaeological study methods for the investigation of the Huelva megalithisms’ (UHU-1263153), at the University of Huelva, funded by the Operative Programme ERDF 2014-2020 and the Department of Economy and Knowledge of the Government of Andalusia. The funding of the open access fee has been covered by the University of Huelva, thanks to an agreement with Cambridge University Press. We are grateful to Dr Juan Carlos Vera-Rodríguez for facilitating the study of the materials and Dr Teodosio Donaire Romero for his collaboration in the petrographic analysis. We are grateful for the valuable comments of the anonymous reviewers and the editor, as their suggestions and recommendations have enriched the work. Funding for open access charge: Universidad de Huelva / CBU

    An Event-Driven Multi-Kernel Convolution Processor Module for Event-Driven Vision Sensors

    Get PDF
    Event-Driven vision sensing is a new way of sensing visual reality in a frame-free manner. This is, the vision sensor (camera) is not capturing a sequence of still frames, as in conventional video and computer vision systems. In Event-Driven sensors each pixel autonomously and asynchronously decides when to send its address out. This way, the sensor output is a continuous stream of address events representing reality dynamically continuously and without constraining to frames. In this paper we present an Event-Driven Convolution Module for computing 2D convolutions on such event streams. The Convolution Module has been designed to assemble many of them for building modular and hierarchical Convolutional Neural Networks for robust shape and pose invariant object recognition. The Convolution Module has multi-kernel capability. This is, it will select the convolution kernel depending on the origin of the event. A proof-of-concept test prototype has been fabricated in a 0.35 m CMOS process and extensive experimental results are provided. The Convolution Processor has also been combined with an Event-Driven Dynamic Vision Sensor (DVS) for high-speed recognition examples. The chip can discriminate propellers rotating at 2 k revolutions per second, detect symbols on a 52 card deck when browsing all cards in 410 ms, or detect and follow the center of a phosphor oscilloscope trace rotating at 5 KHz.Unión Europea 216777 (NABAB)Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

    Neuromorphic Approach Sensitivity Cell Modeling and FPGA Implementation

    Get PDF
    Neuromorphic engineering takes inspiration from biology to solve engineering problems using the organizing principles of biological neural computation. This field has demonstrated success in sensor based applications (vision and audition) as well in cognition and actuators. This paper is focused on mimicking an interesting functionality of the retina that is computed by one type of Retinal Ganglion Cell (RGC). It is the early detection of approaching (expanding) dark objects. This paper presents the software and hardware logic FPGA implementation of this approach sensitivity cell. It can be used in later cognition layers as an attention mechanism. The input of this hardware modeled cell comes from an asynchronous spiking Dynamic Vision Sensor, which leads to an end-to-end event based processing system. The software model has been developed in Java, and computed with an average processing time per event of 370 ns on a NUC embedded computer. The output firing rate for an approaching object depends on the cell parameters that represent the needed number of input events to reach the firing threshold. For the hardware implementation on a Spartan6 FPGA, the processing time is reduced to 160 ns/event with the clock running at 50 MHz.Ministerio de Economía y Competitividad TEC2016-77785-PUnión Europea FP7-ICT-60095
    corecore