1,721,446 research outputs found
Contactless Indoor Human Localization and Identification using Capacitive Sensors for Smart Home Applications
Full text linkL'emergere di nuove tecnologie come Internet of Things (IoT) e Big Data
ha dato origine a una domanda sempre crescente di basso costo, bassa potenza, compattezza e
semplici nodi di sensori per osservare a distanza alcuni fenomeni fisici. L'interno
rilevamento, localizzazione, tracciamento, monitoraggio dell'attività e identificazione umana sono molto
importante in molti contesti come il monitoraggio dell'assistenza sanitaria per gli anziani che vivono
da solo, vita assistita (AAL), sicurezza e sorveglianza.
Il sensing capacitivo è una tecnologia candidata per la localizzazione umana indoor, l'attività
monitoraggio e identificazione. Sensori capacitivi, a basso costo e bassa potenza
i dispositivi hanno guadagnato molta attrattiva dalla comunità scientifica e di ricerca
negli ultimi anni. Questa dissertazione presenta uno studio sperimentale sulla modalità di carico
sensori capacitivi per la localizzazione umana interna e l'identificazione per la casa intelligente
applicazioni. Due diversi tipi di lungo raggio, altamente sensibili e a basso rumore capacitivo
i circuiti di interfaccia front-end del sensore sono progettati, implementati e valutati
per le prestazioni. La prima interfaccia impiega la tecnica basata sulla discriminazione di fase
per osservare i cambiamenti di capacità del sensore, mentre nel secondo circuito, a
viene utilizzato l'approccio basato sulla modulazione di ampiezza di fase. Per ridurre al minimo il rumore, il
viene utilizzato l'approccio di rilevamento capacitivo attivo e i risultati sperimentali e i relativi
vengono fornite analisi statistiche.
Inoltre, l'uso del sensore capacitivo in modalità di carico per distinguere tra un piccolo
gruppo di persone, ad esempio, viene studiata una famiglia. I sensori capacitivi sono usati per misurare
l'interazione di diversi corpi umani con frequenza molto bassa (VLF) e bassa
campi elettrici di frequenza (LF). Le proprietà elettriche e dielettriche del corpo umano
essere una forte funzione non lineare di frequenza varia anche con i tratti fisiologici
del corpo umano e della composizione del tessuto corporeo. Quindi un sensore capacitivo in modalità carico
viene utilizzato nella configurazione del filtro RC passa-basso e per le risposte di magnitudine del filtro
persone diverse che si trovano ad una distanza fissa dal sensore, le cosiddette firme di assorbimento della frequenza corporea del corpo sono misurate usando due tecniche differenti. Il
la prima tecnica si basa sulle misurazioni effettuate nella regione asintotica del
Risposta in frequenza del filtro RC. Nella seconda tecnica, il circuito è configurato in
in modo tale che funzioni sempre vicino al limite per minimizzare l'attenuazione dovuta a
frequenze più alte, quindi aumento del rapporto segnale / rumore (SNR). Il sperimentale
risultati per quattro soggetti maschi con la stessa altezza e gruppo di età, ma diversi pesi
e le composizioni del corpo sono presentate. Un'analisi statistica dei risultati insieme a
vengono anche forniti vantaggi e limiti delle tecniche impiegate.The emergence of new technologies like Internet of Things (IoT) and Big Data
has given rise to an ever increasing demand of low cost, low power, compact and
simple sensor nodes to remotely observe certain physical phenomena. The indoor
human detection, localization, tracking, activity monitoring and identification is very
important in many contexts like health-care monitoring for elderly people living
alone, ambient assisted living (AAL), security and surveillance.
Capacitive sensing is a candidate technology for indoor human localization, activity
monitoring and identification. Capacitive sensors, being low cost and low power
devices has earned a lot of attraction from the research and scientific community
in the recent years. This dissertation presents an experimental study of load mode
capacitive sensors for indoor human localization and identification for smart home
applications. Two different types of long range, highly sensitive and low noise capacitive
sensor front-end interface circuits are designed, implemented and evaluated
for performance. The first interface employs phase discrimination based technique
to observe the changes in capacitance of the sensor, while in the second circuit, a
phase-amplitude modulation based approach is used. To minimize the noise, the
active capacitive sensing approach is employed and experimental results and their
statistical analysis are furnished.
Moreover, the use of load mode capacitive sensor to distinguish among a small
group of people e.g., a family is studied. The capacitive sensors are used to measure
the interaction of different human bodies with very low frequency (VLF) and low
frequency (LF) electric fields. The electric and dielectric properties of human body
being a strong nonlinear function of frequency also vary with the physiological traits
of the human body and body tissue composition. So a load mode capacitive sensor
is used in lowpass RC filter configuration, and magnitude responses of the filter for
different people standing at a fixed distance from the sensor, so called body frequency absorption signatures of the body are measured using two different techniques. The
first technique is based on the measurements taken in the asymptotic region of the
RC filter frequency response. In the second technique, the circuit is configured in
such a way that it always operates near the cutoff to minimize the attenuation due to
higher frequencies, hence increasing signal to noise ratio (SNR). The experimental
results for four male subjects with same height and age group, but different weights
and body compositions are presented. A statistical analysis of the results along with
advantages and limitations of the employed techniques is also provided
Cooperative caching policies in multi-hop wireless networks
No full textMobile networks have been experiencing an impressive growth in the data traffic in recent years. Video data represented more than half of global mobile data traffic beginning in 2012, indicating that it is having an immediate impact on traffic even today, not just in the future. This enormous traffic growth urges network operators to continuously invest money in enhancing existing wireless infrastructure, whereas users have to spend more money for contents or cloud based services than for the communication access. This dichotomy motivates new network paradigms in which the users' wireless terminals cooperate to decrease the load in the wireless network infrastructure: the Quality of Experience of the user is improved, even if the network infrastructure has not been upgraded. The cooperation among the wireless terminals motivates towards the novel content-centric networking (CCN) paradigm in which a content-based addressing allows to identify the requested content independently from its location. The content-reuse, content-localization and the large storage capacity in modern mobile devices enable the adoption of cooperative caching schemes, in which each mobile device acts as a caching node. Our contributions lies in proposing a novel caching insertion policy and performing a thorough comparison between different local and distributed caching policies. Our proposed policy is an "interest-based insertion policy" in which user's interest for a particular content is considered as the main metric of its insertion into the cache. Results obtained suggest that our proposed policy outperforms other stateof- the-art insertion policies. Furthermore, the performance of local caching and distributed caching policies was evaluated under different synthetic request models as well as with real content request traces obtained from an Italian ISP. Comparison results for both fix wireless and mobility traces show that local caching performs better than the more complex distributed policie
Managing organizational legitimacies in times of institutional change- a case of humanitarian development NGOs in Pakistan
No full textThe aim of this study is to generate an in-depth
understanding for the existence and causes of legitimacy concerns of NGOs in
the complex Humanitarian Development Field (HDF) in Pakistan. NGOs are found
short on delivering both the agenda of humanitarian relief and mainstream
development. Beyond failure of delivery the acceptance of these entities is
otherwise also low in a Muslim Pakhtun backyard of the world. Yet the NGO
sector has shown boom post 9/11 to ultimately find itself implicated by the
State in Pakistan post 2013 on various pretexts. What necessitates the State to
oppose NGOs in a region that needs multiple players to fight underdevelopment
and conflict? The leading question this research addresses is thus, why NGO
legitimacies are declining in the region.
Empirically rooted in three cases (local NGOs), this
qualitative research abducts causal mechanisms of the incidence of decreased NGOs’
legitimacy through examining reality at three levels under a Critical Realist
methodology. Firstly, at the empirical level are increased events of coercion,
regulative constraints, operational obstruction, and intimidation of NGOs.
Secondly, at the actual level are the three identified mechanisms that explains
why NGOs face marginalization including the ‘purported’ anti-state stance,
commercialization of the institution of HDF and NGOs therein, and the opacity
and corruption that NGOs structures increasingly embed. These mechanisms work
in a complex context that has been explained as three discrete phases of
humanitarian crisis in the study region post 9/11. Thirdly, at the real level,
NGOs face legitimacy crisis in large part because of a shift in institutional
norms of humanitarianism and developmentalism both globally and nationally.
Research outcomes reveal, foremost, that legitimacy crisis
may be traced to the existence of multiple institutional logics (of
humanitarianism and developmentalism) ingrained in HDF with both positive and
detrimental consequences for NGOs. It is demonstrated that competing logics has
been a source of under development of NGOs, and consequently that of the
underdevelopment of the institutional environments in which they operate. At
the 3 same time, a positive spinoff of competing logics has been recorded as
NGOs are gradually turning into sustainable organizations to suggest that
logics multiplicity force organizations to course correction and embeddedness
in newer institutional orders.
However this course correction of NGOs as made manifest
through their strategies is just a small fraction of NGOs response to their
alienation. In line with Neo-institutional theory, NGOs adopt a variety of
other responses to the sometimes contradictory logics of HDF. Evidence reveals
that NGOs show agency, despite institutional disdain and coercive procedures,
in gaining different forms of legitimacies at the meso level of
organization-field interaction. Particularly important are the NGOs quest for
attaining normative/regulative, cognitive, and output legitimacies. Faced with
multiple normative, cultural, religious, and practical impediments, it is both
intriguing and fascinating to see small relief NGOs survive and mold into
‘development’ organizations in an environment hostile to their existence.
The contributions of the study are three-fold: a) an
analytical frame combining Institutional theory and critical realism to explain
how field-level institutional changes affect organizations in both beneficial
and detrimental ways, b) a theoretical contribution focusing on four insights
on NGOs structures viz, temporality of legitimacy challenge, legitimacy
fatigue, emergence of an entrepreneurial streak amongst NGOs, and a possible
beginning of NGOs playing institutional entrepreneurs in HDF to give it newer
institutional outlook.; and c) a practitioner focused emancipatory contribution
where NGOs as social actors need to ensure a higher level of agency awareness
to overcome the challenges of decreased legitimacies and play their due role in
development of the region.
The research addresses a glaring research gap in
humanitarian development chain by focusing on the lower most tiers of local
NGOs who are a critical conduit between donors and beneficiaries in crisis
environments</p
Educational Exclusion in Digital Literacy - a comparitive study of British Muslim Girl Schools
No full textFaith schools represent an important role in educating children in Britain
and this has a long established history that continues to evolve with the
diversity in our communities. Over more recent years there has been a
growth in Muslim schools in England and this is viewed as a growing part
of faith schools in Britain today.
Muslim faith schools are integral to the transformation and restructuring of
many in the British Muslim communities that is centered around the
negotiation of new composite identities, changing family patterns and
relationships, political activism and the fight against social exclusion
(Hussain & O’Brien, 2000)
Interest-based cooperative caching in multi-hop wireless networks
Full text linkAbstract—New communication protocols, as WiFi Direct, are now available to enable efficient Device-to-Device (D2D) communications in wireless networks based on portable devices. At the same time, new network paradigms, as Content-Centric-Networking (CCN), allow a communication focused on the content and not its location within the network, enabling a flexible location for the content, which can be cached in the nodes across the network. In such context, we consider a multi-hop wireless network adopting CCN-like cooperative caching, in which each user terminal acts also as a caching node. We propose an interestbased insertion policy for the caching, based on the concept of “social-distance ” borrowed by online recommendation systems, to improve the performance of the overall network of caches; the main idea is to store only the contents which appear to be of interest for the local user. We show that our proposed scheme outperforms other well-known insertion policies, that are oblivious of such social-distance, in terms of cache hit probability and access delays. I
High Level Synthesis based FPGA Implementation of H.264/AVC Sub-Pixel Luma Interpolation Filters
Full text linkIn High Efficiency Video Coding (HEVC) and H.264/AVC video coding standards, Interpolation filtering used for sub-pixel interpolation is one of the most computational intensive parts of the standards. Video processing systems are becoming more complex thus decreasing the productivity of the hardware designers and the software programmers, producing design productivity gap. To fill this productivity gap, hardware and software fields are bridged through High Level Synthesis (HLS), thus improving the productivity of the hardware designers. In this paper, we present a HLS based FPGA Implementation of sub-pixel Luma Interpolation of H.264/AVC. Xilinx Vivado HLS tools are used for the FPGA implementation of interpolation filtering on Xilinx xc7z020clg481-1 device. Our design can achieve the frame processing speed of 41 QFHD, i.e. 3840x2160@41fps. The development time is significantly decreased by the HLS tools
Long range, high sensitivity, low noise capacitive sensor for tagless indoor human localization
Full text linkCapacitive sensors have important advantages and are widely used, but typically up to sensing distances comparable to sensor size. We present the design and experimental results of a self-contained long range capacitive sensor that is suitable for indoor human localization. We make differential measurements of the reactance effects of sensor plate capacitance using a constant excitation frequency, which is both less prone to noise and easier to filter. The experimental results show good sensor sensitivity up to 200 cm for a 16 cm square sensor plate, low noise and good measurement stability
Performance of machine learning classifiers for indoor person localization with capacitive sensors
Full text linkAccurate tagless indoor person localization is important for several applications, such as assisted living and health monitoring. Machine learning (ML) classifiers can effectively mitigate sensor data variability and noise due to deployment-specific environmental conditions. In this paper, we use experimental data from a capacitive sensor-based indoor human localization system in a 3 m × 3 m room to comparatively analyze the performance of Weka collection ML classifiers. We compare the localization performance of the algorithms, its variation with the training set size, and the algorithm resource requirements for both training and inferring. The results show a large variance between algorithms, with the best accuracy, precision, and recall exceeding 93% and 0.05 m average localization error
High sensitivity, low noise front-end for long range capacitive sensors for tagless indoor human localization
Full text linkCapacitive sensors are used in many applications due to their multiple advantages, but typically up to distances comparable to sensor dimensions. We present the design and the experimental results of a self-contained long range capacitive sensor front-end that is based on phase modulation and is suitable for indoor human localization. The changes in reactance due to the changes in the sensor capacitance modulate the phase of a carrier frequency, which is then demodulated using a XOR gate as quadrature detector. A phase modulated carrier is both less susceptible to noise and easier to filter. The experimental results show a very good sensor sensitivity up to 150 cm for a 16 cm square sensor plate, very low noise and good measurement stability
- …
