965 research outputs found
PONDER - A Real time software backend for pulsar and IPS observations at the Ooty Radio Telescope
This paper describes a new real-time versatile backend, the Pulsar Ooty Radio
Telescope New Digital Efficient Receiver (PONDER), which has been designed to
operate along with the legacy analog system of the Ooty Radio Telescope (ORT).
PONDER makes use of the current state of the art computing hardware, a
Graphical Processing Unit (GPU) and sufficiently large disk storage to support
high time resolution real-time data of pulsar observations, obtained by
coherent dedispersion over a bandpass of 16 MHz. Four different modes for
pulsar observations are implemented in PONDER to provide standard reduced data
products, such as time-stamped integrated profiles and dedispersed time series,
allowing faster avenues to scientific results for a variety of pulsar studies.
Additionally, PONDER also supports general modes of interplanetary
scintillation (IPS) measurements and very long baseline interferometry data
recording. The IPS mode yields a single polarisation correlated time series of
solar wind scintillation over a bandwidth of about four times larger (16 MHz)
than that of the legacy system as well as its fluctuation spectrum with high
temporal and frequency resolutions. The key point is that all the above modes
operate in real time. This paper presents the design aspects of PONDER and
outlines the design methodology for future similar backends. It also explains
the principal operations of PONDER, illustrates its capabilities for a variety
of pulsar and IPS observations and demonstrates its usefulness for a variety of
astrophysical studies using the high sensitivity of the ORT.Comment: 25 pages, 14 figures, Accepted by Experimental Astronom
Simulation of networks of spiking neurons: A review of tools and strategies
We review different aspects of the simulation of spiking neural networks. We
start by reviewing the different types of simulation strategies and algorithms
that are currently implemented. We next review the precision of those
simulation strategies, in particular in cases where plasticity depends on the
exact timing of the spikes. We overview different simulators and simulation
environments presently available (restricted to those freely available, open
source and documented). For each simulation tool, its advantages and pitfalls
are reviewed, with an aim to allow the reader to identify which simulator is
appropriate for a given task. Finally, we provide a series of benchmark
simulations of different types of networks of spiking neurons, including
Hodgkin-Huxley type, integrate-and-fire models, interacting with current-based
or conductance-based synapses, using clock-driven or event-driven integration
strategies. The same set of models are implemented on the different simulators,
and the codes are made available. The ultimate goal of this review is to
provide a resource to facilitate identifying the appropriate integration
strategy and simulation tool to use for a given modeling problem related to
spiking neural networks.Comment: 49 pages, 24 figures, 1 table; review article, Journal of
Computational Neuroscience, in press (2007
Usability improvements for the Friend-to-Friend Computing Pidgin Plugin
Olemasoleva Pidgini laienduse analüüs ja edasiarendus. Lisatud mitmed uued kasutajaliidese elemendid ja hõlbustatud ligipääs rakenduse funktsionaalsusele.Analysis of pre-existing Friend-to-Friend Computing Pidgin plugin and improving it. Several new user interface related features developed and better access to existing functionality
WIFI indoor positioning for mobile devices, an application for the UJI Smart Campus
Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.Smart Campus has emerged as a study platform of a Smart City. There are some
similarities between the Campus and a City. Due to this, is possible use a Smart
Campus as attesting bench and then apply these investigations to implement in a
Smart City. One of this potential technologies is the Indoor Positioning System
using the Wi-Fi network. The aim of this work is research and implement a
mobile application to carry out the indoor positioning in the context of the UJI
Smart Campus. The prototype developed allows to perform the first part of the
Wi-Fi Indoor Positioning, the mapping phase. This application implements a
system to display and all UJI cartography (campus basemap, UJI buildings and
UJI buildings interiors). When whole system will be developed, it will allow
implement the indoor positioning in a future applications for the Smart Campus
A Linux-based graphical user interface for the creation and reading of the frame format: Version 2.4
To gain further knowledge of how the universe began, a new international co-operated project wishes not only to see stars exploding, but also to hear the explosion. It is theorised that the ability to listen to an explosion is possible by detecting gravitational waves. Gravitational waves are omitted when a star explodes, travelling through the cosmos at an exceptional speed. It is estimated that a gravity wave takes only 40 milliseconds to pass through the earth. Thus the aim of this international collaboration is to detect a gravitational wave. To accurately detect such waves, there needs to be several global detectors. If a phenomenon is detected at one detector, data from other detectors is compared; to investigate whether this event occurred simultaneously around the world. An integral component of gravitational wave detection includes the real· time saving of signals as data on a generic storage media, e.g. a standard hard disk and later permanent storage e.g. on compact discs. It is therefore crucial that there is a constant 24-hour data gathering from the detectors. 24-hours of constant data gathering requires a system that can facilitate for the acquisition of the data and save the data into a standard format, which was agreed upon by all the global gravity wave detection sites (known as the frame format. Please refer to appendix 9.1 for further details concerning this format.). This accommodates the exchange of the data for analysis between detection sites. To create exchangeable files in the frame format requires the data to be passed through C Unix based libraries. These libraries are cumbersome to utilize, require sufficient computing skills to use and are very inefficient when working with large amounts of data. The purpose of this honours project is to research and construct a graphical user interface under the Linux Operating System, to the frame libraries, in order to greatly assist in the data storage and exchange process
The Third NASA Goddard Conference on Mass Storage Systems and Technologies
This report contains copies of nearly all of the technical papers and viewgraphs presented at the Goddard Conference on Mass Storage Systems and Technologies held in October 1993. The conference served as an informational exchange forum for topics primarily relating to the ingestion and management of massive amounts of data and the attendant problems involved. Discussion topics include the necessary use of computers in the solution of today's infinitely complex problems, the need for greatly increased storage densities in both optical and magnetic recording media, currently popular storage media and magnetic media storage risk factors, data archiving standards including a talk on the current status of the IEEE Storage Systems Reference Model (RM). Additional topics addressed System performance, data storage system concepts, communications technologies, data distribution systems, data compression, and error detection and correction
Comunicações veiculares híbridas
Vehicle Communications is a promising research field, with a great potential for
the development of new applications capable of improving road safety, traffic efficiency,
as well as passenger comfort and infotainment. Vehicle communication
technologies can be short-range, such as ETSI ITS-G5 or the 5G PC5 sidelink
channel, or long-range, using the cellular network (LTE or 5G). However, none of
the technologies alone can support the expected variety of applications for a large
number of vehicles, nor all the temporal and spatial requirements of connected
and autonomous vehicles. Thus, it is proposed the collaborative or hybrid use of
short-range communications, with lower latency, and of long-range technologies,
potentially with higher latency, but integrating aggregated data of wider geographic
scope.
In this context, this work presents a hybrid vehicle communications model, capable
of providing connectivity through two Radio Access Technologies (RAT), namely,
ETSI ITS-G5 and LTE, to increase the probability of message delivery and, consequently,
achieving a more robust, efficient and secure vehicle communication
system. The implementation of short-range communication channels is done using
Raw Packet Sockets, while the cellular connection is established using the Advanced
Messaging Queuing Protocol (AMQP) protocol.
The main contribution of this dissertation focuses on the design, implementation
and evaluation of a Hybrid Routing Sublayer, capable of isolating messages that
are formed/decoded from transmission/reception processes. This layer is, therefore,
capable of managing traffic coming/destined to the application layer of intelligent
transport systems (ITS), adapting and passing ITS messages between the highest
layers of the protocol stack and the available radio access technologies.
The Hybrid Routing Sublayer also reduces the financial costs due to the use of
cellular communications and increases the efficiency of the use of the available
electromagnetic spectrum, by introducing a cellular link controller using a Beacon
Detector, which takes informed decisions related to the need to connect to a cellular
network, according to different scenarios.
The experimental results prove that hybrid vehicular communications meet the requirements
of cooperative intelligent transport systems, by taking advantage of
the benefits of both communication technologies. When evaluated independently,
the ITS-G5 technology has obvious advantages in terms of latency over the LTE
technology, while the LTE technology performs better than ITS-G5, in terms of
throughput and reliability.As Comunicações Veiculares são um campo de pesquisa promissor, com um grande
potencial de desenvolvimento de novas aplicações capazes de melhorar a segurança
nas estradas, a eficiência do tráfego, bem com o conforto e entretenimento dos
passageiros. As tecnologias de comunicação veícular podem ser de curto alcance,
como por exemplo ETSI ITS-G5 ou o canal PC5 do 5G, ou de longo alcance, recorrendo
à rede celular (LTE ou 5G). No entanto, nenhuma das tecnologias por
si só, consegue suportar a variedade expectável de aplicações para um número de
veículos elevado nem tampouco todos os requisitos temporais e espaciais dos veículos
conectados e autónomos. Assim, é proposto o uso colaborativo ou híbrido de
comunicações de curto alcance, com latências menores, e de tecnologias de longo
alcance, potencialmente com maiores latências, mas integrando dados agregados
de maior abrangência geográfica.
Neste contexto, este trabalho apresenta um modelo de comunicações veiculares
híbrido, capaz de fornecer conectividade por meio de duas Tecnologias de Acesso
por Rádio (RAT), a saber, ETSI ITS-G5 e LTE, para aumentar a probabilidade de
entrega de mensagens e, consequentemente, alcançar um sistema de comunicação
veicular mais robusto, eficiente e seguro. A implementação de canais de comunicação
de curto alcance é feita usando Raw Packet Sockets, enquanto que a ligação
celular é estabelecida usando o protocolo Advanced Messaging Queuing Protocol
(AMQP).
A contribuição principal desta dissertação foca-se no projeto, implementação e avaliação
de uma sub camada hibrída de encaminhamento, capaz de isolar mensagens
que se formam/descodificam a partir de processos de transmissão/receção. Esta
camadada é, portanto, capaz de gerir o tráfego proveniente/destinado à camada
de aplicação de sistemas inteligentes de transportes (ITS) adaptando e passando
mensagens ITS entre as camadas mais altas da pilha protocolar e as tecnologias
de acesso rádio disponíveis.
A sub camada hibrída de encaminhamento também potencia uma redução dos custos
financeiros devidos ao uso de comunicações celulares e aumenta a eficiência do
uso do espectro electromagnético disponível, ao introduzir um múdulo controlador
da ligação celular, utilizando um Beacon Detector, que toma decisões informadas
relacionadas com a necessidade de uma conexão a uma rede celular, de acordo com
diferentes cenários.
Os resultados experimentais comprovam que as comunicações veículares híbridas
cumprem os requisitos dos sistemas cooperativos de transporte inteligentes, ao
tirarem partido das vantagens de ambas tecnologias de comunicação. Quando
avaliadas de forma independente, constata-se que que a tecnologia ITS-G5 tem
vantagens evidentes em termos de latência sobre a tecnologia LTE, enquanto que
a tecnologia LTE tem melhor desempenho que a LTE, ai nível de débito e fiabilidade.Mestrado em Engenharia Eletrónica e Telecomunicaçõe
Power, Avionics and Software - Phase 1.0:
This report describes Power, Avionics and Software (PAS) 1.0 subsystem integration testing and test results that occurred in August and September of 2013. This report covers the capabilities of each PAS assembly to meet integration test objectives for non-safety critical, non-flight, non-human-rated hardware and software development. This test report is the outcome of the first integration of the PAS subsystem and is meant to provide data for subsequent designs, development and testing of the future PAS subsystems. The two main objectives were to assess the ability of the PAS assemblies to exchange messages and to perform audio testing of both inbound and outbound channels. This report describes each test performed, defines the test, the data, and provides conclusions and recommendations
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