1,720,999 research outputs found
A Framework to Facilitate Wireless Sensor Network Application Development
No full textAnotācija
Sākotnējā vīzija par bezvadu sensoru tīkliem paredzēja, ka
tie kļūs par vērtīgu rīku daudzām lietotāju grupām: gan dažādu
jomu zinātniekiem, gan praktiķiem. Taču bezvadu sensoru tīklu
programmatūras izstrāde ir sarežģīta, jo tie apvieno
resursierobežotu iegulto ierīču sarežģītību ar tīklotu ierīču
sarežģītību. Tas ir viens no iemesliem, kāpēc sensoru tīkli vēl nav
kļuvuši par plaša patēriņa tehnoloģiju.
Šī problēma ir daļēji risināma, piedāvājot bezvadu sensoru
tīklu programmatūras izstrādātājiem piemērotus programmizstrādes
rīkus, programmēšanas valodas un bibliotēkas. Tāpēc disertācijas
ietvaros ir izveidota rinda pieeju bezvadu sensoru tīklu
lietojumprogrammu izstrādes atvieglošanai, ieskaitot: jaunu
lietojumprogrammu izstrādes valodu, kura ļauj lietojumprogrammas
definēt īsākā un mazāk sarežģītā veidā, un pieeju sensoru tīklu
operētājsistēmu resursefektivitātes palielināšanai. Šīs pieejas ir
integrētas vienotā programmatūras ietvarā, kopā ar citu autora un
viņa pētniecības grupas izstrādāto programmatūru.
Ietvars ir paredzēts divām lietotāju grupām: pirmkārt,
iesācējiem programmētājiem, otrkārt, profesionāliem
programmētājiem, tai skaitā arī tiem, kuriem ir tikai neliela pieredze
bezvadu sensoru tīklos.
Veiktie eksperimenti rāda, ka piedāvātās pieejas ļauj iegūt
lietojumprogrammas ar mazāku resursu patēriņu un zemāku koda
sarežģītību.
Atslēgvārdi: bezvadu sensoru tīkli, operētājsistēmas,
domēnspecifiskās valodas.Abstract
Wireless sensor networks is a technology that was originally
envisioned as a tool for broad range of purposes and target
audiences. However, wireless sensor network software
development is complicated, because it brings together the
complexity of resource-constrained embedded system software
and the complexity of distributed system software. This is one of
the reasons why sensor networks have not yet become an
ubiquitous technology.
This problem is partially solvable by decreasing the
accidental software development complexity that is at the moment
present in the process of sensor network application development.
The sensor network application developer must be provided with
appropriate development tools, languages and libraries in order to
allow him to focus on the essential complexity of software
development. Therefore this dissertation presents a number of
approaches that facilitate sensor network application
programming, including: a new application development language
that allows to write applications in more concise and less complex
way, and an approach to increase the resource-efficiency of sensor
network operating systems. The approaches are integrated in a
unified framework, along with other software designed by the
author and his research group.
This framework is targeted towards two categories of users:
firstly, novice programmers, secondly, professional programmers,
including programmers with limited experience in wireless sensor
networks. The evaluation shows that these approaches lead to
applications with decreased resource usage and lower code
complexity.
Keywords: wireless sensor networks, operating systems,
domain-specific languages
atiselsts/sphere-house-network-performance-2019: Initial release
No full textExperimental network performance data from the SPHERE Hous
TSCH-Sim: Scaling Up Simulations of TSCH and 6TiSCH Networks
No full textTSCH (Time-Slotted Channel Hopping) and 6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e) low-power wireless networks are becoming prominent in the industrial Internet of Things (IoT) and other areas where high reliability is needed in conjunction with energy efficiency. Due to the complexity of IoT deployments, network simulations are typically used for pre-deployment design and validation. However, it is currently difficult and time-consuming to simulate large-scale IoT networks with thousands of nodes. This paper proposes TSCH-Sim: a new discrete event simulator for IEEE 802.15.4-2015 TSCH and 6TiSCH networks. The evaluation shows that simulation results obtained with TSCH-Sim show a good match with results from other simulators that are commonly used to investigate TSCH networks. At the same time, TSCH-Sim is faster than these alternatives at least by an order of magnitude, making it more practical to carry out simulations of large networks
Towards Body Coupled Communication for eHealth: Experimental Study of Human Body Frequency Response
No full textHuman Body as a Signal Transmission Medium for Body-Coupled Communication: Galvanic-Mode Models
No full textSignal propagation models play a fundamental role in radio frequency communication research. However, emerging communication methods, such as body-coupled communication (BCC), require the creation of new models. In this paper, we introduce mathematical models that approximate the human body as an electrical circuit, as well as linear regression- and random forest-based predictive models that infer the expected signal loss from its frequency, measurement point locations, and body parameters. The results demonstrate a close correspondence between the amplitude-frequency response (AFR) predicted by the electrical circuit models and the experimental data gathered from volunteers. The accuracy of our predictive models was assessed by using their root mean square errors (RMSE), ranging from 1.5 to 7 dB depending on the signal frequency within the 0.05 to 20 MHz range. These results allow researchers and engineers to simulate and forecast the expected signal loss within BCC systems during their design phase
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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