809 resultados para Frail syndrome, Inertial sensor, Mobile phone, Sit-to-stand, Stand-to-sit
Resumo:
Indoor positioning has become an emerging research area because of huge commercial demands for location-based services in indoor environments. Channel State Information (CSI) as fine-grained physical layer information has been recently proposed to achieve high positioning accuracy by using range based methods, e.g., trilateration. In this work, we propose to fuse the CSI-based ranging and velocity estimated from inertial sensors by an enhanced particle filter to achieve highly accurate tracking. The algorithm relies on some enhanced ranging methods and further mitigates the remaining ranging errors by a weighting technique. Additionally, we provide an efficient method to estimate the velocity based on inertial sensors. The algorithms are designed in a network-based system, which uses rather cheap commercial devices as anchor nodes. We evaluate our system in a complex environment along three different moving paths. Our proposed tracking method can achieve 1.3m for mean accuracy and 2.2m for 90% accuracy, which is more accurate and stable than pedestrian dead reckoning and range-based positioning.
The Technology Gap and the Growth of the Firm: A Case Study of China's Mobile-phone Handset Industry
Resumo:
We have examined the way in which local Chinese firms confronted with a technology gap have achieved growth, using the Chinese handset industry as a case study. Chinese local firms have lacked technology, and have therefore turned to outside firms for development, design, and manufacturing, while they themselves have focused on sales and marketing, using their advantage of familiarity with the Chinese market. Consequently, by establishing a growth condition in which their selection of boundaries counterbalances the technology gap they have been able to expand their market share in comparison with foreign firms.
Resumo:
Mobile phones are becoming increasingly popular and are already the first access technology to information and communication. However, people with disabilities have to face a lot of barriers when using this kind of technology. This paper presents an Accessible Contact Manager and a Real Time Text application, designed to be used by all users with disabilities. Both applications are focused to improve accessibility of mobile phones.
Resumo:
This article evaluates an authentication technique for mobiles based on gestures. Users create a remindful identifying gesture to be considered as their in-air signature. This work analyzes a database of 120 gestures of different vulnerability, obtaining an Equal Error Rate (EER) of 9.19% when robustness of gestures is not verified. Most of the errors in this EER come from very simple and easily forgeable gestures that should be discarded at enrollment phase. Therefore, an in-air signature robustness verification system using Linear Discriminant Analysis is proposed to infer automatically whether the gesture is secure or not. Different configurations have been tested obtaining a lowest EER of 4.01% when 45.02% of gestures were discarded, and an optimal compromise of EER of 4.82% when 19.19% of gestures were automatically rejected.
Resumo:
Natural disasters affect hundreds of millions of people worldwide every year. Emergency response efforts depend upon the availability of timely information, such as information concerning the movements of affected populations. The analysis of aggregated and anonymized Call Detail Records (CDR) captured from the mobile phone infrastructure provides new possibilities to characterize human behavior during critical events. In this work, we investigate the viability of using CDR data combined with other sources of information to characterize the floods that occurred in Tabasco, Mexico in 2009. An impact map has been reconstructed using Landsat-7 images to identify the floods. Within this frame, the underlying communication activity signals in the CDR data have been analyzed and compared against rainfall levels extracted from data of the NASA-TRMM project. The variations in the number of active phones connected to each cell tower reveal abnormal activity patterns in the most affected locations during and after the floods that could be used as signatures of the floods - both in terms of infrastructure impact assessment and population information awareness. The epresentativeness of the analysis has been assessed using census data and civil protection records. While a more extensive validation is required, these early results suggest high potential in using cell tower activity information to improve early warning and emergency management mechanisms.
Resumo:
Natural disasters affect hundreds of millions of people worldwide every year. Emergency response efforts depend upon the availability of timely information, such as information concerning the movements of affected populations. The analysis of aggregated and anonymized Call Detail Records (CDR) captured from the mobile phone infrastructure provides new possibilities to characterize human behavior during critical events. In this work, we investigate the viability of using CDR data combined with other sources of information to characterize the floods that occurred in Tabasco, Mexico in 2009. An impact map has been reconstructed using Landsat-7 images to identify the floods. Within this frame, the underlying communication activity signals in the CDR data have been analyzed and compared against rainfall levels extracted from data of the NASA-TRMM project. The variations in the number of active phones connected to each cell tower reveal abnormal activity patterns in the most affected locations during and after the floods that could be used as signatures of the floods - both in terms of infrastructure impact assessment and population information awareness. The representativeness of the analysis has been assessed using census data and civil protection records. While a more extensive validation is required, these early results suggest high potential in using cell tower activity information to improve early warning and emergency management mechanisms.
Resumo:
The first automatic mobile phone service was launched in Australia in 1981, with the first cellular mobile service following in 1987. In 2003 there were over 14.5 million mobile phone subscribers, and the technology had become central to everyday life and culture. Despite the significance of mobile phones, little has been written about their Australian histories. This paper offers some notes on the history of mobile telecommunications in Australia. As well as reviewing the development of the mobile phone in Australia, it looks at the cultural representation of this technology.
Resumo:
Enhanced data services through mobile phones are expected to be soon fully transactional and embedded within future mobile consumption practices. While private services will surely continue to take the lead, others such as government and NGOs will become more prominent m-players. It is not yet sure which form of technological standards will take the lead including enhance SMS based operations or Internet based specifically developed mobile phone applications. With the introduction of interactive transactions via mobile phones, currently untapped segment of the populations (without computers) have the potential to be accessed. Our research, as a reflection of the current market situation in an emerging country context, in the case of mobile phones analyzes the current needs or emergence of dependencies regarding the use of m/e-government services from the perspective of municipality officers. We contend that more research is needed to understand current preparatory bottlenecks and front loading activities to be able to encourage future intention to use e-government services through mobile phone technologies. This study highlights and interprets the current emerging practices and praxis for consuming m-government services within government.
Resumo:
In emerging markets, the amount of mobile communication and the number of occasions mobile phones are used are increasing. More and more settings appropriate or not for mobile phone usage are being exposed. Although prohibited by many governments, there is evidence that use of new mobile devices while driving are somehow becoming current everyday practice, hence legitimatizing usage for many users. Dominant dangerous behavior in the absence of enforced legal framework is being deployed and has become routine for many m-users. This chapter adopts a qualitative case study approach (20 cases) to examine the public transport drivers' motives, logic and legitimacy processes. The question which these issues raise in the light of advancing m-technologies is: How do, in the context of emerging market, undesired emerging routines enactment get to be reflected upon and voluntarily disregarded to maximize the benefits of m-technologies while minimizing their drawbacks? Findings point out at multiple motives for usage including external social pressure through the ubiquitous 24/7 usage of mtechnology, lack of alternative communication protocol, real time need for action and from an internal perspectives boredoms, lack of danger awareness, blurring of the boundaries between personal and business life and lack of job fulfillment are uncovered as key factors. As secondary dynamic factors such as education, drivers work' histories, impunity, lack of strong consumer opposition appear central in shaping the development of the routines. © 2011, IGI Global.
Resumo:
OBJECTIVES: Mobile phones (MP) are used extensively and yet little is known about the effects they may have on human physiology. There have been conflicting reports regarding the relation between MP use and the electroencephalogram (EEG). The present study suggests that this conflict may be due to methodological differences such as exposure durations, and tests whether exposure to an active MP affects EEG as a function of time. METHODS: Twenty-four subjects participated in a single-blind fully counterbalanced cross-over design, where both resting EEG and phase-locked neural responses to auditory stimuli were measured while a MP was either operating or turned off. RESULTS: MP exposure altered resting EEG, decreasing 1-4 Hz activity (right hemisphere sites), and increasing 8-12 Hz activity as a function of exposure duration (midline posterior sites). MP exposure also altered early phase-locked neural responses, attenuating the normal response decrement over time in the 4-8 Hz band, decreasing the response in the 1230 Hz band globally and as a function of time, and increasing midline frontal and lateral posterior responses in the 30-45 Hz band. CONCLUSIONS: Active MPs affect neural function in humans and do so as a function of exposure duration. The temporal nature of this effect may contribute to the lack of consistent results reported in the literature.
Resumo:
This article explores the use of mobile phones as portable remediated sound devices for mobile listening — from boom boxes to personal stereos and mp3 players. This mode of engaging the city through music playing and listening reveals a particular urban strategy and acoustic urban politics. It increases the sonic presence of mobile owners and plays a role in territorialisation dynamics, as well as in eliciting territorial controversies in public. These digital practices play a key role in the enactment of the urban mood and ambience, as well as in the modulation of people’s presence — producing forms of what Spanish architect Roberto González calls portable urbanism: an entanglement of the digital, the urban and the online that activates a map of a reality over the fabric of the city, apparently not so present, visible and audible