3,744 research outputs found
Multi-scale path planning for a planetary exploration vehicle with multiple locomotion modes
Planetary exploration vehicles (rovers) can encounter with a great variety of
situations. Most of them are related to the terrain, which can cause the end of
the mission if these vehicles are not able to traverse it. It was the case of Spirit
rover, which got stuck in loose sand, making it impossible to continue advancing.
A solution to this is to make rovers capable of modifying their locomotion to
traverse terrains with particular terramechanic parameters.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Robust symmetric multiplication for programmable analog VLSI array processing
This paper presents an electrically programmable analog multiplier. The circuit performs the multiplication between an input variable and an electrically selectable scaling factor. The multiplier is divided in several blocks: a linearized transconductor, binary weighted current mirrors and a differential to single-ended current adder. This paper shows the advantages introduced using a linearized OTA-based multiplier. The circuit presented renders higher linearity and symmetry in the output current than a previously reported single-transistor multiplier. Its inclusion in an array processor based on CNN allows for a more accurate implementation of the processing model and a more robust weight distribution scheme than those found in previous designs.Office of Naval Research (USA) N-00014- 02-1-0884Ministerio de Ciencia y Tecnología TIC2003-09817-C02-0
A Focal-Plane Image Processor for Low Power Adaptive Capture and Analysis of the Visual Stimulus
Portable applications of artificial vision are limited by the fact that conventional processing schemes fail to meet the specifications under a tight power budget. A bio-inspired approach, based in the goal-directed organization of sensory organs found in nature, has been employed to implement a focal-plane image processor for low power vision applications. The prototype contains a multi-layered CNN structure concurrent with 32times32 photosensors with locally programmable integration time for adaptive image capture with on-chip local and global adaptation mechanisms. A more robust and linear multiplier block has been employed to reduce irregular analog wave propagation ought to asymmetric synapses. The predicted computing power per power consumption, 142MOPS/mW, is orders of magnitude above what rendered by conventional architectures
Perfomance analysis of hybrid systems based on externally heayed closed-cycle engines
This work presents a comparative analysis of hybrid
systems that make use of closed-cycle externally heated
bottoming systems. Two options are considered:
reciprocating (Stirling) engines and supercritical carbon
dioxide turbines. These engines share the common
feature of working on closed cycles with optimised fluids
(H2 and CO2 respectively). However, they differ in their
internal structure: Stirling engines make use of volumetric
machinery whereas the SCO2 system is composed by
turbomachinery. In both cases, the working fluid is
subjected to very high pressure and temperature in the
range of 50-200 bar and 40-650 ºC.
A brief description of both bottoming systems is
provided in the article along with the expected
performance of each case in on-design and off-design
(part load) conditions. The analysis is therefore split into
two stages. First, a comparison is shown for on-design
operation aiming to evaluate the maximum efficiency
attainable by the proposed systems. Second, a
preliminary analysis of off-design operation is presented.
The paper concludes that hybrid systems based on
atmospheric fuel cells and externally heated closed-cycle
bottoming engines have the potential to outperform
conventional pressurised fuel cells and gas turbines
hybrids while preserving the topping system from the
demanding operating conditions of the latter configuratio
Performance evaluation and limitations of a vision system on a reconfigurable/programmable chip
This paper presents a survey of the characteristics of a vision system implemented in
a reconfigurable/programmable chip (FPGA). System limitations and performance have been
evaluated in order to derive specifications and constraints for further vision system synthesis.
The system hereby reported has a conventional architecture. It consists in a central
microprocessor (CPU) and the necessary peripheral elements for data acquisition, data storage
and communications. It has been designed to stand alone, but a link to the programming and
debugging tools running in a digital host (PC) is provided. In order to alleviate the
computational load of the central microprocessor, we have designed a visual co-processor in
charge of the low-level image processing tasks. It operates autonomously, commanded by the
CPU, as another system peripheral. The complete system, without the sensor, has been
implemented in a single reconfigurable chip as a SOPC. The incorporation of a dedicated visual
co-processor, with specific circuitry for low-level image processing acceleration, enhances the
system throughput outperforming conventional processing schemes. However, timemultiplexing
of the dedicated hardware remains a limiting factor for the achievable peak
computing power. We have quantified this effect and sketched possible solutions, like
replication of the specific image processing hardware
Sistemas logísticos flexibles: cadenas de suministro inteligentes en América Latina
Este documento brinda un análisis de estos sistemas logísticos flexibles o cadenas de suministro inteligentes en América Latina, con el objetivo de comprender las condiciones disponibles y aspectos fundamentales para lograr procesos de transformación digital en la región. El estudio considera el contexto de cada país frente a la incorporación de tecnología y la importancia de temas institucionales, como la necesidad de un mecanismo de coordinación de políticas públicas para la digitalización, la importancia de líderes públicos de alto nivel y la participación del sector privado para que la transformación digital sea posible.Resumen .-- Introducción .-- I. Factores determinantes para la implementación tecnológica; cadenas de suministro inteligentes en América Latina .-- II. La conectividad en la región .-- III. Configuración espacial y vinculación de tecnologías smart con las cadenas de valor en la región .-- IV. Mejoras de interoperabilidad e integración del sistema logístico regional .-- V. Conclusiones
Informe Portuario 2021: las primeras señales de recuperación en el transporte marítimo internacional vía contenedores de América Latina y el Caribe
En 2020 el mundo fue impactado por la pandemia del COVID-19, que cambió la vida cotidiana de las personas y dejó efectos devastadores. Mucho se ha analizado sobre la pandemia y sus efectos en distintos sectores. Debido a la trayectoria del Boletín FAL en temas marítimos y portuarios, el presente número tiene como principal objetivo analizar si se ha dado inicio a la recuperación del transporte marítimo internacional vía contenedores en América Latina y el Caribe (ALC), así como también presentar la evolución y consecuencias del alza de los fletes marítimos de contenedores como uno de los temas emergentes que surgieron con la pandemia y que aún persisten
2021 Port Report: Early signs of a recovery in international container shipping in Latin America and the Caribbean
In 2020 the entire world was overwhelmed by the coronavirus disease (COVID-19) pandemic, which changed the daily lives of people around the globe and had a devastating impact on humankind. The pandemic and its effects in different sectors have been the object of intensive analysis. This edition of the FAL Bulletin will focus on the question as to whether or not the international container shipping industry in Latin America and the Caribbean is on the path to recovery. It will also look at the upward trend in container freight rates and its implications as one of the emerging issues associated with the pandemic and its aftermath
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