860 resultados para Location Tracking


Relevância:

70.00% 70.00%

Publicador:

Resumo:

Os serviços baseados em localização vieram dar um novo alento à criatividade dos programadores de aplicações móveis. A vulgarização de dispositivos com capacidades de localização integradas deu origem ao desenvolvimento de aplicações que gerem e apresentam informação baseada na posição do utilizador. Desde então, o mercado móvel tem assistido ao aparecimento de novas categorias de aplicações que tiram proveito desta capacidade. Entre elas, destaca-se a monitorização remota de dispositivos, que tem vindo a assumir uma importância crescente, tanto no sector particular como no sector empresarial. Esta dissertação começa por apresentar o estado da arte sobre os diferentes sistemas de posicionamento, categorizados pela sua eficácia em ambientes internos ou externos, assim como diferentes protocolos de comunicação em tempo quase-real. É também feita uma análise ao estado actual do mercado móvel. Actualmente o mercado possui diferentes plataformas móveis com características únicas que as fazem rivalizar entre si, com vista a expandirem a sua quota de mercado. É por isso elaborado um breve estudo sobre os sistemas operativos móveis mais relevantes da actualidade. É igualmente feita uma abordagem mais profunda à arquitectura da plataforma móvel da Apple - o iOS – que serviu de base ao desenvolvimento de uma solução optimizada para localização e monitorização de dispositivos móveis. A monitorização implica uma utilização intensiva de recursos energéticos e de largura de banda que os dispositivos móveis da actualidade não estão aptos a suportar. Dado o grande consumo energético do GPS face à precária autonomia destes dispositivos, é apresentado um estudo em que se expõem soluções que permitem gerir de forma optimizada a utilização do GPS. O elevado custo dos planos de dados facultados pelas operadoras móveis é também considerado, pelo que são exploradas soluções que visam minimizar a utilização de largura de banda. Deste trabalho, nasce a aplicação EyeGotcha, que para além de permitir localizar outros utilizadores de dispositivos móveis de forma optimizada, permite também monitorizar as suas acções baseando-se num conjunto de regras pré-definidas. Estas acções são reportadas às entidades monitoras, de modo automatizado e sob a forma de alertas. Visionando-se a comercialização da aplicação, é portanto apresentado um modelo de negócio que permite obter receitas capazes de cobrirem os custos de manutenção de serviços, aos quais o funcionamento da aplicação móvel está subjugado.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Attractive business cases in various application fields contribute to the sustained long-term interest in indoor localization and tracking by the research community. Location tracking is generally treated as a dynamic state estimation problem, consisting of two steps: (i) location estimation through measurement, and (ii) location prediction. For the estimation step, one of the most efficient and low-cost solutions is Received Signal Strength (RSS)-based ranging. However, various challenges - unrealistic propagation model, non-line of sight (NLOS), and multipath propagation - are yet to be addressed. Particle filters are a popular choice for dealing with the inherent non-linearities in both location measurements and motion dynamics. While such filters have been successfully applied to accurate, time-based ranging measurements, dealing with the more error-prone RSS based ranging is still challenging. In this work, we address the above issues with a novel, weighted likelihood, bootstrap particle filter for tracking via RSS-based ranging. Our filter weights the individual likelihoods from different anchor nodes exponentially, according to the ranging estimation. We also employ an improved propagation model for more accurate RSS-based ranging, which we suggested in recent work. We implemented and tested our algorithm in a passive localization system with IEEE 802.15.4 signals, showing that our proposed solution largely outperforms a traditional bootstrap particle filter.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

This paper presents an overview of preliminary results of investigations within the WHERE2 Project on identifying promising avenues for location aided enhancements to wireless communication systems. The wide ranging contributions are organized according to the following targeted systems: cellular networks, mobile ad hoc networks (MANETs) and cognitive radio. Location based approaches are found to alleviate significant signaling overhead in various forms of modern communication paradigms that are very information hungry in terms of channel state information at the transmitter(s). And this at a reasonable cost given the ubiquitous availability of location information in recent wireless standards or smart phones. Location tracking furthermore opens the new perspective of slow fading prediction.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Työn teoriaosuudessa tutustutaan ensin paikkatiedon käsitteeseen ja paikkatietoa hyödyntäviin palveluihin. Lisäksi perehdytään paikannukseen langattomissa lähiverkoissa ja erityisesti paikannukseen tämän diplomityön osalta käytettävässä verkossa. Työn teoriaosuudessa tutustutaan myös paikkatietoa hyödyntävien palveluiden hyöty- sekä haittanäkökulmiin. Teoriaosuudessa käydään myös läpi tällä hetkellä yleisimmät pikaviestintäarkkitehtuurit ja tutustutaan tarkemmin Jabber–pikaviestintäohjelmiston käyttämään protokollaan. Lopuksi tarkastellaan paikkatiedon hyödyntämiseen liittyviä lakiteknisiä seikkoja ja henkilön yksityisyyden suojaa. Diplomityön käytännön osuudessa tutustutaan paikkatietoa hyödyntävän palvelinkomponentin toteutukseen Jabber–arkkitehtuuria hyväksikäyttäen. Jabber-palvelinohjelmisto ja tehty komponentti toimivat langattomassa lähiverkossa (WLPR.NET), jota ylläpitää Lappeenrannan teknillisen yliopiston tietoliikennetekniikan laitos. Verkon käyttäjät voivat rekisteröityä palvelun käyttäjiksi, jonka jälkeen palvelinkomponentti pitää kirjaa rekisteröityneiden käyttäjien paikkatiedosta ja sen muutoksista. Lisäksi käyttäjät voivat hakea muiden käyttäjien paikkatietoa asiakasohjelmistossa toimivan hakutoiminnon avulla. Käyttäjien paikkatieto saadaan käyttämällä jo olemassa olevaa tekniikkaa.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Työn tavoitteena on tutkia ja suunnitella kuinka paikkatietoa, mobiililaitteita sekä matkapuhelinverkkoja käyttäen voidaan toteuttaa käyttäjien seuranta- ja ohjausjärjestelmä. Järjestelmän avulla käyttäjät voivat seurata reaaliaikaisesti muiden käyttäjien sijainteja sekä ohjata muita käyttäjiä haluttuihin sijainteihin mobiililaitteen avulla. Järjestelmä pyritään suunnittelemaan laajennettavaksi. Lähtökohtana on toteuttaa seurannan sekä ohjauksen toteuttavat runkokomponentit, joiden päälle voidaan toteuttaa erityyppisiä sovelluksia. Tutkittavia asioita ovat matkapuhelinverkkojen tiedonsiirtomahdollisuudet, paikannustekniikat, mobiililaitteiden suorituskyky sekä resurssit, käyttäjien yksityisyyden ja tiedonsiirron turvaaminen sekä mobiililaitteista sekä langattomuudesta aiheutuvat haasteet yleisesti. Tutkimusten sekä suunnittelun pohjalta järjestelmästä toteutetaan esimerkkisovellus, jolla suoritetaan käytännön testaus. Testauksessa mitataan järjestelmän resurssien käyttöä ja suorituskykyä sekä testataan suunnittelun pohjalta tehtyjen ratkaisujen toimivuutta. Lopuksi työssä analysoidaan järjestelmän toimivuutta testaus- sekä mittaustulosten pohjalta.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Liikkuvan kenttätyön työntekijät suorittavat työpäivän aikana työtä useassa eri työkohteessa. Työkohteilla suoritettujen työtehtävien kirjaus tapahtuu usein jälkikäteen ja muistinvaraisesti. Diplomityön tavoitteena on esittää ratkaisu liikkuvan kenttätyön työkirjausten automatisointiin. Tavoitteen mukaisen etätunnistusta ja paikannusta hyödyntävän mobiilijärjestelmän avulla työntekijöiden käsinkirjoitetut ja mahdollisesti puutteelliset työkirjaukset korvataan automaattisilla ja täsmällisillä kirjauksilla. Järjestelmän tavoitteena on vähentää työntekijöiden työkuormaa. Työssä arvioidaan etätunnistuksen hyödyntämistä mobiilisovelluksen käyttöä helpottavana tekniikkana. Parhaimmillaan etätunnistus poistaa kokonaan mobiililaitteen näppäilytarpeen, mutta aiheuttaa osaltaan lisää työtä järjestelmän ylläpitoon. Työn tuloksissa esitetään myös satelliittipaikannuksen todettu tarkkuus ja soveltuvuus liikkuvan kenttätyön tarpeisiin taajama- ja kaupunkialueella. Varsinkin kaupunkialueella satelliittiperustaisen paikkatiedon tehokas hyödyntäminen edellyttää suodatusta ja älykkyyttä paikkatiedon prosessointiin.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

A major weakness among loading models for pedestrians walking on flexible structures proposed in recent years is the various uncorroborated assumptions made in their development. This applies to spatio-temporal characteristics of pedestrian loading and the nature of multi-object interactions. To alleviate this problem, a framework for the determination of localised pedestrian forces on full-scale structures is presented using a wireless attitude and heading reference systems (AHRS). An AHRS comprises a triad of tri-axial accelerometers, gyroscopes and magnetometers managed by a dedicated data processing unit, allowing motion in three-dimensional space to be reconstructed. A pedestrian loading model based on a single point inertial measurement from an AHRS is derived and shown to perform well against benchmark data collected on an instrumented treadmill. Unlike other models, the current model does not take any predefined form nor does it require any extrapolations as to the timing and amplitude of pedestrian loading. In order to assess correctly the influence of the moving pedestrian on behaviour of a structure, an algorithm for tracking the point of application of pedestrian force is developed based on data from a single AHRS attached to a foot. A set of controlled walking tests with a single pedestrian is conducted on a real footbridge for validation purposes. A remarkably good match between the measured and simulated bridge response is found, indeed confirming applicability of the proposed framework.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Garment information tracking is required for clean room garment management. In this paper, we present a camera-based robust system with implementation of Optical Character Reconition (OCR) techniques to fulfill garment label recognition. In the system, a camera is used for image capturing; an adaptive thresholding algorithm is employed to generate binary images; Connected Component Labelling (CCL) is then adopted for object detection in the binary image as a part of finding the ROI (Region of Interest); Artificial Neural Networks (ANNs) with the BP (Back Propagation) learning algorithm are used for digit recognition; and finally the system is verified by a system database. The system has been tested. The results show that it is capable of coping with variance of lighting, digit twisting, background complexity, and font orientations. The system performance with association to the digit recognition rate has met the design requirement. It has achieved real-time and error-free garment information tracking during the testing.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Wireless Sensor Networks (WSNs) are highly distributed systems in which resource allocation (bandwidth, memory) must be performed efficiently to provide a minimum acceptable Quality of Service (QoS) to the regions where critical events occur. In fact, if resources are statically assigned independently from the location and instant of the events, these resources will definitely be misused. In other words, it is more efficient to dynamically grant more resources to sensor nodes affected by critical events, thus providing better network resource management and reducing endto- end delays of event notification and tracking. In this paper, we discuss the use of a WSN management architecture based on the active network management paradigm to provide the real-time tracking and reporting of dynamic events while ensuring efficient resource utilization. The active network management paradigm allows packets to transport not only data, but also program scripts that will be executed in the nodes to dynamically modify the operation of the network. This presumes the use of a runtime execution environment (middleware) in each node to interpret the script. We consider hierarchical (e.g. cluster-tree, two-tiered architecture) WSN topologies since they have been used to improve the timing performance of WSNs as they support deterministic medium access control protocols.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Relevância:

30.00% 30.00%

Publicador:

Resumo:

É possível assistir nos dias de hoje, a um processo tecnológico evolutivo acentuado por toda a parte do globo. No caso das empresas, quer as pequenas, médias ou de grandes dimensões, estão cada vez mais dependentes dos sistemas informatizados para realizar os seus processos de negócio, e consequentemente à geração de informação referente aos negócios e onde, muitas das vezes, os dados não têm qualquer relacionamento entre si. A maioria dos sistemas convencionais informáticos não são projetados para gerir e armazenar informações estratégicas, impossibilitando assim que esta sirva de apoio como recurso estratégico. Portanto, as decisões são tomadas com base na experiência dos administradores, quando poderiam serem baseadas em factos históricos armazenados pelos diversos sistemas. Genericamente, as organizações possuem muitos dados, mas na maioria dos casos extraem pouca informação, o que é um problema em termos de mercados competitivos. Como as organizações procuram evoluir e superar a concorrência nas tomadas de decisão, surge neste contexto o termo Business Intelligence(BI). A GisGeo Information Systems é uma empresa que desenvolve software baseado em SIG (sistemas de informação geográfica) recorrendo a uma filosofia de ferramentas open-source. O seu principal produto baseia-se na localização geográfica dos vários tipos de viaturas, na recolha de dados, e consequentemente a sua análise (quilómetros percorridos, duração de uma viagem entre dois pontos definidos, consumo de combustível, etc.). Neste âmbito surge o tema deste projeto que tem objetivo de dar uma perspetiva diferente aos dados existentes, cruzando os conceitos BI com o sistema implementado na empresa de acordo com a sua filosofia. Neste projeto são abordados alguns dos conceitos mais importantes adjacentes a BI como, por exemplo, modelo dimensional, data Warehouse, o processo ETL e OLAP, seguindo a metodologia de Ralph Kimball. São também estudadas algumas das principais ferramentas open-source existentes no mercado, assim como quais as suas vantagens/desvantagens relativamente entre elas. Em conclusão, é então apresentada a solução desenvolvida de acordo com os critérios enumerados pela empresa como prova de conceito da aplicabilidade da área Business Intelligence ao ramo de Sistemas de informação Geográfica (SIG), recorrendo a uma ferramenta open-source que suporte visualização dos dados através de dashboards.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Ship tracking systems allow Maritime Organizations that are concerned with the Safety at Sea to obtain information on the current location and route of merchant vessels. Thanks to Space technology in recent years the geographical coverage of the ship tracking platforms has increased significantly, from radar based near-shore traffic monitoring towards a worldwide picture of the maritime traffic situation. The long-range tracking systems currently in operations allow the storage of ship position data over many years: a valuable source of knowledge about the shipping routes between different ocean regions. The outcome of this Master project is a software prototype for the estimation of the most operated shipping route between any two geographical locations. The analysis is based on the historical ship positions acquired with long-range tracking systems. The proposed approach makes use of a Genetic Algorithm applied on a training set of relevant ship positions extracted from the long-term storage tracking database of the European Maritime Safety Agency (EMSA). The analysis of some representative shipping routes is presented and the quality of the results and their operational applications are assessed by a Maritime Safety expert.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Ants live in organized societies with a marked division of labor among workers, but little is known about how this division of labor is generated. We used a tracking system to continuously monitor individually tagged workers in six colonies of the ant Camponotus fellah over 41 days. Network analyses of more than 9 million interactions revealed three distinct groups that differ in behavioral repertoires. Each group represents a functional behavioral unit with workers moving from one group to the next as they age. The rate of interactions was much higher within groups than between groups. The precise information on spatial and temporal distribution of all individuals allowed us to calculate the expected rates of within- and between-group interactions. These values suggest that the network of interaction within colonies is primarily mediated by age-induced changes in the spatial location of workers.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

PURPOSE: To use diffusion-tensor (DT) magnetic resonance (MR) imaging in patients with essential tremor who were treated with transcranial MR imaging-guided focused ultrasound lesion inducement to identify the structural connectivity of the ventralis intermedius nucleus of the thalamus and determine how DT imaging changes correlated with tremor changes after lesion inducement. MATERIALS AND METHODS: With institutional review board approval, and with prospective informed consent, 15 patients with medication-refractory essential tremor were enrolled in a HIPAA-compliant pilot study and were treated with transcranial MR imaging-guided focused ultrasound surgery targeting the ventralis intermedius nucleus of the thalamus contralateral to their dominant hand. Fourteen patients were ultimately included. DT MR imaging studies at 3.0 T were performed preoperatively and 24 hours, 1 week, 1 month, and 3 months after the procedure. Fractional anisotropy (FA) maps were calculated from the DT imaging data sets for all time points in all patients. Voxels where FA consistently decreased over time were identified, and FA change in these voxels was correlated with clinical changes in tremor over the same period by using Pearson correlation. RESULTS: Ipsilateral brain structures that showed prespecified negative correlation values of FA over time of -0.5 or less included the pre- and postcentral subcortical white matter in the hand knob area; the region of the corticospinal tract in the centrum semiovale, in the posterior limb of the internal capsule, and in the cerebral peduncle; the thalamus; the region of the red nucleus; the location of the central tegmental tract; and the region of the inferior olive. The contralateral middle cerebellar peduncle and bilateral portions of the superior vermis also showed persistent decrease in FA over time. There was strong correlation between decrease in FA and clinical improvement in hand tremor 3 months after lesion inducement (P < .001). CONCLUSION: DT MR imaging after MR imaging-guided focused ultrasound thalamotomy depicts changes in specific brain structures. The magnitude of the DT imaging changes after thalamic lesion inducement correlates with the degree of clinical improvement in essential tremor.