232 research outputs found

    Deploying a Communicating Automatic Weather Station on an Alpine Glacier

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    The cost and effort of installing and maintaining an automatic weather station (AWS) on a glacier may be mitigated by the possibility of gathering sensor data in near real-time, and of controlling and programming the station remotely. In this paper we report our experience with upgrading an existing AWS, operating over an Italian glacier, from a mere datalogger into a networked sensing station. Design choices, energy constraints and power-aware programming of the station determined by harsh environment are discussed. Deployment operations and results are described. The upgraded AWS provides low-power connectivity from a remote location and is able to serve as a base station for a wireless sensor network working in the glacier

    From single point of measurement to distributed sensing in long-term glacier monitoring

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    Glacial environment monitoring is a key task in understanding natural phenomena related to global warming. For the last 30 years, Automatic Weather Stations (AWSs) have been spreading among the meteorological and geophysical community, and are on the way to become a de facto standard to perform long-lasting unattended data acquisitions in single localized points of interest. Sensor Networks (SNs), on the other hand, promise the possibility to perform measurements with a higher spatial density and lower cost. Designing and developing a SN for glacial environment face particular challenges for embedded electronics and sensor systems, which is why SNs are still under research and development in this eld. This paper surveys the AWSs and SNs for glacial monitoring applications and compares their characteristics

    From single point of measurement to distributed sensing in long-term glacier monitoring

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    Glacial environment monitoring is a key task in understanding natural phenomena related to global warming. For the last 30 years, Automatic Weather Stations (AWSs) have been spreading among the meteorological and geophysical community, and are on the way to become a de facto standard to perform long-lasting unattended data acquisitions in single localized points of interest. Sensor Networks (SNs), on the other hand, promise the possibility to perform measurements with a higher spatial density and lower cost. Designing and developing a SN for glacial environment face particular challenges for embedded electronics and sensor systems, which is why SNs are still under research and development in this field. This paper surveys the AWSs and SNs for glacial monitoring applications and compares their characteristics

    Real-Time Embedded Control System for a Portable Meteorological Station

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    The aim of this work is to design and code an embedded system for a portable automatic weather station. The portable station includes high performance sensors to measure parameters such as: i) wind speed and direction, micro perturbations and wind gusts, ii) air temperature, iii) solar radiation, iv) relative humidity, and v) atmospheric pressure. The main contribution of this work is the development of an embedded control system operating in real time. This system is based on a Field Programmable Gate Array (FPGA) device. The method developed guarantees high-resolution data acquisition of a number of samples in real time. The samples obtained are grouped and stored in a database, which will be used as a starting point for further analysis

    Air temperature variability over three glaciers in the Ortles-Cevedale (Italian Alps): Effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling

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    Glacier mass balance models rely on accurate spatial calculation of input data, in particular air temperature. Lower temperatures (the so-called glacier cooling effect), and lower temperature variability (the so-called glacier damping effect) generally occur over glaciers, compared to ambient conditions. These effects, which depend on the geometric characteristics of glaciers and display a high spatial and temporal variability, have been mostly investigated on medium- to large-size glaciers so far, while observations on smaller ice bodies are scarce. Using a dataset from 8 on-glacier and 4 off-glacier weather stations, collected in summer 2010 and 2011, we analyzed the air temperature distribution variability and wind regime over three different glaciers in the Ortles-Cevedale. The magnitude of the cooling effect and the occurrence of katabatic boundary layer (KBL) processes showed remarkable differences among the three ice bodies, highlighting suggesting the likely existence of important reinforcing mechanisms during glacier decay and disintegration. None of the methods proposed in the literature for calculating on-glacier temperature from off-glacier data fully reproduced our observations. Among them, the more physically-based procedure of Greuell and B\uf6hm [1998] provided the best overall results where the KBL prevail, but it was not effective elsewhere (i.e. on smaller ice bodies and close to the glacier margins). The accuracy of air temperature estimations strongly impacted the results from a mass balance model which was applied to the three investigated glaciers. Most importantly, even small temperature deviations caused distortions in parameter calibration, thus compromising the model generalizability

    enhancing performance of wireless sensor networks in glacial environments using wake up receivers

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    Development of radio telemetry enabled long-term monitoring of hard-to-reach and harsh environments. This paper compares two WSN deployment projects for gathering sensor data in glacier monitoring application — GlacsWeb and PermaSense, in terms of system design and wireless communication. We discuss the potential benefits of energy-efficient event detection using wake-up receivers together with duty-cycled communication. We show that adding a WURx would increase the average power consumption of Dozer protocol for 10%, but it would reduce the delay from 2 minutes to several milliseconds. Besides for event detection, WURx could be used for synchronizing the beginning of the TDMA communication, which would eliminate the need for clock drift compensation, making the protocol simpler and lighter

    SensorScope: Application-Specific Sensor Network for Environmental Monitoring

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    SensorScope is a turnkey solution for environmental monitoring systems, based on a wireless sensor network and resulting from a collaboration between environmental and network researchers. Given the interest in climate change, environmental monitoring is a domain where sensor networks will have great impact by providing high resolution spatio-temporal data for long periods of time. SensorScope is such a system, which has already been successfully deployed multiple times in various environments (e.g., mountainous, urban). Here, we describe the overall hardware and software architectures and especially focus on the sensor network itself. We also describe one of our most prominent deployments, on top of a rock glacier in Switzerland, which resulted in the description of a micro-climate phenomenon leading to cold air release from a rock-covered glacier in a region of high alpine risks. Another focus of this paper is the description of what happened behind the scenes to turn SensorScope from a laboratory experiment into successful outdoor deployments in harsh environments. Illustrated by various examples, we point out many lessons learned while working on the project. We indicate the importance of simple code, well suited to the application, as well as the value of close interaction with end-users in planning and running the network and finally exploiting the data

    Tracking retreat processes at the Falljökull Glacier, SE Iceland

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    In glacial systems, hydrological forcing of ice velocity may lead to instability and accelerated mass loss. However, recent studies have demonstrated that the relationship between ice melt and ice dynamics is non-linear because subglacial drainage configuration strongly modulates meltwater inputs and results in asynchroneity between surface melt production and ice movement. Furthermore, subglacial drainage undergoes temporal evolution and can vary spatially between and within individual glaciers. As such, the degree of connectivity between ice melt and ice dynamics exhibits spatio-temporal variability. To address this, time-lapse images from Falljökull, SE Iceland, were analysed using Pointcatcher, a feature tracking software. Surface velocities and thinning rates were quantified for the period 2011-2013 and compared to results from energy balance modelling (EBM) to determine the climatic, hydrological and structural controls on glacier dynamics. The results show that melt production at Falljökull is closely linked to energy inputs to the glacier surface, although consistent thinning underestimation by the EBM, equivalent to ~1-3 m, reflects the poor optimisation of the model for thin debris cover. In addition, melt production is strongly modulated by individual events e.g. Grímsvötn eruption, which modify surface conditions and enhance/supress melt. A clear relationship between ice melt and ice dynamics is also evident in these data although subglacial drainage structure i.e. discrete/distributed, and surface conditions e.g. debris or snow cover, account for periods of de-coupling. Hydrologically induced speed-up events are identified and occur more readily when inefficient distributed systems are present. In contrast, flow variability is markedly reduced when meltwater inputs are suppressed and when efficient discrete drainage is present. Enhanced flow is strongly linked to sliding at the ice-bed interface although this varies spatially and temporally as a function of subglacial drainage configuration. Finally, these data conflict markedly with previous research which inferred that Falljökull was stagnant and wasting away in-situ. Instead, Falljökull is ‘active’ with movement through ice deformation, basal sliding and subglacial deformation although forward motion is insufficient to offset retreat

    Context Aware Computing or the Sense of Context

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    ITALIANO: I sistemi ubiquitous e pervasivi, speciali categorie di sistemi embedded (immersi), possono essere utilizzati per rilevare il contesto che li circonda. In particolare, i sistemi context-aware sono in grado di alterare il loro stato interno e il loro comportamento in base all’ambiente (context) che percepiscono. Per aiutare le persone nell’espletare le proprie attivitá, tali sistemi possono utilizzare le conoscenze raccolte attorno a loro. Un grande sforzo industriale e di ricerca, orientato all’innovazione dei sensori, processori, sistemi operativi, protocolli di comunicazione, e framework, offre molte tecnologie definibili abilitanti, come le reti di sensori wireless o gli Smartphone. Tuttavia, nonostante tale sforzo significativo, l’adozione di sistemi pervasivi che permettano di migliorare il monitoraggio dello sport, l’allenamento e le tecnologie assistive é ancora piuttosto limitato. Questa tesi individua due fattori determinanti per questo basso utilizzo delle tecnologie pervasive, principalmente relativi agli utenti. Da un lato il tentativo degli esperti e dei ricercatori dell’informatica di indurre l’adozione di soluzioni informatiche, trascurando parzialmente l’interazione con gli utenti finali, dall’altro lato una scarsa attenzione all’interazione tra uomo e computer. Il primo fattore puó essere tradotto nella mancanza di attenzione a ció che é rilevante nel contesto dei bisogni (speciali) dell’utente. Il secondo é rappresentato dall’utilizzo diffuso di interfacce grafiche di presentazione delle informazioni, che richiede un elevato livello di sforzo cognitivo da parte degli utenti. Mentre lo studio della letteratura puó fornire conoscenze sul contesto dell’utente, solo il contatto diretto con lui arricchisce la conoscenza di consapevolezza, fornendo una precisa identificazione dei fattori che sono piú rilevanti per il destinatario dell’applicazione. Per applicare con successo le tecnologie pervasive al campo dello sport e delle tecnologie assistive, l’identificazione dei fattori rilevanti é una premessa necessaria, Tale processo di identificazione rappresenta l’approccio metodologico principale utilizzato per questa tesi. Nella tesi si analizzano diversi sport (canottaggio, nuoto, corsa ) e una disabilitá (la cecitá), per mostrare come la metodologia di investigazione e di progettazione proposta venga messa in pratica. Infatti i fattori rilevanti sono stati identificati grazie alla stretta collaborazione con gli utenti e gli esperti nei rispettivi campi. Si descrive il processo di identificazione, insieme alle soluzioni elaborate su misura per il particolare campo d’uso. L’uso della sonificazione, cioé la trasmissione di informazioni attraverso il suono, si propone di affrontare il secondo problema presentato, riguardante le interfacce utente. L’uso della sonificazione puó facilitare la fruizione in tempo reale delle informazioni sulle prestazioni di attivitá sportive, e puó contribuire ad alleviare parzialmente la disabilitá degli utenti non vedenti. Nel canottaggio, si é identificato nel livello di sincronia del team uno dei fattori rilevanti per una propulsione efficace dell’imbarcazione. Il problema di rilevare il livello di sincronia viene analizzato mediante una rete di accelerometri wireless, proponendo due diverse soluzioni. La prima soluzione é basata sull’indice di correlazione di Pearson e la seconda su un approccio emergente chiamato stigmergia. Entrambi gli approcci sono stati testati con successo in laboratorio e sul campo. Inoltre sono state sviluppate due applicazioni, per smartphone e PC, per fornire la telemetria e la sonificazione del moto di una barca a remi. Nel campo del nuoto é stata condotta una ricerca in letteratura riguardo la convinzione diffusa di considerare la cinematica come il fattore rilevante della propulsione efficace dei nuotatori. Questa indagine ha richiamato l’attenzione sull’importanza di studiare il cosiddetto feel-for-water (sensazione-dell’-acqua) percepito dai nuotatori d’alto livello. É stato progettato un innovativo sistema, per rilevare e comunicare gli effetti fluidodinamici causati dallo spostamento delle masse d’acqua intorno alle mani dei nuotatori. Il sistema é in grado di trasformare la pressione dell’acqua, misurata con sonde Piezo intorno alle mani, in un bio-feedback auditivo, pensato per i nuotatori e gli allenatori, come base per un nuovo modo di comunicare la sensazione-dell’acqua. Il sistema é stato testato con successo nel campo e ha dimostrato di fornire informazioni in tempo reale per il nuotatore e il formatore. Nello sport della corsa sono stati individuati due parametri rilevanti: il tempo di volo e di contatto dei piedi. É stato progettato un sistema innovativo per ottenere questi parametri attraverso un unico accelerometro montato sul tronco del corridore ed é stato implementato su uno smartphone. Per ottenere il risultato voluto é stato necessario progettare e realizzare un sistema per riallineare virtualmente gli assi dell’accelerometro e per estrarre il tempo di volo e di contatto dal segnale dell’accelerometro riallineato. L’applicazione per smartphone completa é stata testata con successo sul campo, confrontando i valori con quelli di attrezzature specializzate, dimostrando la sua idoneitá come ausilio pervasivo all’allenamento di corridori. Per esplorare le possibilitá della sonificazione usata come una base per tecnologia assistiva, abbiamo iniziato una collaborazione con un gruppo di ricerca presso l’Universitá di Scienze Applicate, Ginevra, in Svizzera. Tale collaborazione si é concentrata su un progetto chiamato SeeColOr (See Color with an Orchestra - vedere i colori con un’orchestra). In particolare, abbiamo avuto l’opportunitá di implementare il sistema SeeColOr su smartphone, al fine di consentire agli utenti non vedenti di utilizzare tale tecnologia su dispositivi leggeri e a basso costo. Inoltre, la tesi esplora alcune questioni relative al campo del rilevamento ambientale in ambienti estremi, come i ghiacciai, utilizzando la tecnologia delle Wireless Sensor Networks. Considerando che la tecnologia é simile a quella usata in altri contesti presentati, le considerazioni possono facilmente essere riutilizzate. Si sottolinea infatti che i problemi principali sono legati alla elevata difficoltá e scarsa affidabilitá di questa tecnologia innovativa rispetto alle altre soluzioni disponibili in commercio , definite legacy, basate solitamente su dispositivi piú grandi e costosi, chiamati datalogger. La tesi presenta i problemi esposti e le soluzioni proposte per mostrare l’applicazione dell’approccio progettuale cercato e definito durante lo sviluppo delle attività sperimentali e la ricerca che le ha implementate. ---------------------------------------- ENGLISH: Ubiquitous and pervasive systems, special categories of embedded systems, can be used to sense the context in their surrounding. In particular, context-aware systems are able to alter their internal state and their behaviour based on the context they perceive. To help people in better performing their activities, such systems must use the knowledge gathered about the context. A big research and industrial effort, geared towards the innovation of sensors, processors, operating systems, communication protocols, and frameworks, provides many "enabling" technologies, such as Wireless Sensor Networks or Smartphones. However, despite that significant effort, the adoption of pervasive systems to enhance sports monitoring, training and assistive technologies is still rather small. This thesis identifies two main issues concerning this low usage of pervasive technologies, both mainly related to users. On one side the attempt of computer science experts and researchers to induce the adoption of information technology based solutions, partially neglecting interaction with end users; on the other side a scarce attention to the interaction between humans and computers. The first can be translated into the lack of attention at what is relevant in the context of the user’s (special) needs. The second is represented by the widespread usage of graphical user interfaces to present information, requiring a high level of cognitive effort. While literature studies can provide knowledge about the user’s context, only direct contact with users enriches knowledge with awareness, providing a precise identification of the factors that are more relevant to the user. To successfully apply pervasive technologies to the field of sports engineering and assistive technology, the identification of relevant factors is an obliged premise, and represents the main methodological approach used throughout this thesis. This thesis analyses different sports (rowing, swimming, running) and a disability (blindness), to show how the proposed design methodology is put in practice. Relevant factors were identified thanks to the tight collaboration with users and experts in the respective fields. The process of identification is described, together with the proposed application tailored for the special field. The use of sonification, i.e. conveying information as sound, is proposed to leverage the second presented issue, that regards the user interfaces. The usage of sonification can ease the exploitation of information about performance in real-time for sport activities and can help to partially leverage the disability of blind users. In rowing, the synchrony level of the team was identified as one of the relevant factors for effective propulsion. The problem of detecting the synchrony level is analysed by means of a network of wireless accelerometers, proposing two different solutions. The first solution is based on Pearson’s correlation index and the second on an emergent approach called stigmergy. Both approaches were successfully tested in laboratory and in the field. Moreover two applications, for smartphones and PCs, were developed to provide telemetry and sonification of a rowing boat’s motion. In the field of swimming, an investigation about the widespread belief considering kinematics as the relevant factor of effective propulsion of swimmers drew attention to the importance of studying the so called "feel-for-water" experienced by elite swimmers. An innovative system was designed to sense and communicate fluid-dynamic effects caused by moving water masses around swimmers hands. The system is able to transform water pressure, measured with Piezo-probes, around hands into an auditive biofeedback, to be used by swimmers and trainers, as the base for a new way of communication about the "feel-for-water". The system was successfully tested in the field and proved to provide real-time information for the swimmer and the trainer. In running sports two relevant parameters are time of flight and contact of feet. An innovative system was designed to obtain these parameters using a single trunk mounted accelerometer and was implemented on a smartphone. To achieve the intended result it was necessary to design and implement a system to virtually realign the axes of the accelerometer and to extract time of flight and time of contact phases from the realigned accelerometer signal. The complete smartphone application was successfully tested in the field with specialized equipment, proving its suitability in enhancing training of runners with a pervasive system. To explore possibilities of sonification applied as an assistive technology, we started a collaboration with research group from University of Applied Science, Geneva, Switzerland, focused on a project called SeeColOr (See Color with an Orchestra). In particular we had the opportunity to implement the SeeColOr system on smartphones, in order to enable blind users to use that technology on low cost and lightweight devices. Moreover, the thesis exposes some issues related to a field, environmental sensing in extreme environments, like glaciers, using the innovative Wireless Sensor Networks technology. Considering that the technology is similar to the one used in other presented contexts, learned lessons can easily be reused. It is emphasized that the main problems are related to the high difficulty and low reliability of that innovative technology with respect to other "legacy" commercially available solutions, based on expensive and bigger devices, called dataloggers. The thesis presents the exposed problems and proposed solutions to show the application of the design approach strived during the development and research

    RABID: Basal conditions on Rutford Ice Stream, West Antarctica: Hot-water drilling and downhole instrumentation. British Antarctic Survey Field Report, R/2004/S3 [BAS Archives Ref: AD6/2R/2004/S3]

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    The main fieldwork for project AFI 1-05 (the RABID project) was carried out on Rutford Ice Stream in the 2004/05 field season. The biggest scientific task was to access the ice stream bed using a hot-water drill. This would enable a number of investigations within the bed and the ice. The project also involved a substantial suite of surface geophysical measurements. Together, these formed an integrated programme studying ice dynamics, basal conditions and climate and glacial history. Although the drilling reached within ~100 m of the bottom of the ice (ice thickness ~2200 m), irretrievable equipment failure meant that we did not reach the ice stream bed. The surface work was much more successful and is giving significant and in some cases, unexpected, results
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