921 research outputs found
Radiocarbon chronology of dolmens in the Iberian southwest: architectural sequence and temporality in the el Pozuelo megalithic complex (Huelva, Spain)
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
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
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
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
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
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
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
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
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
Cuentas de collar de variscita y otras piedras verdes en tumbas megalíticas del suroeste de la Península Ibérica: cuestiones acerca de su producción, circulación y presencia en contextos funerarios
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