1,720,979 research outputs found
Predicting User Movements in Heterogeneous Indoor Environments by Reservoir Computing
Full text linkAnticipating user localization by making accurate predictions on its indoor movement patterns is a fundamental challenge for achieving higher degrees of personalization and reactivity in smarthome environments. We propose an approach to real-time movement forecasting founding on the efficient Reservoir Computing paradigm, predicting user movements based on streams of Received Signal Strengths collected by wireless motes distributed in the home environment. The ability of the system to generalize its predictive performance to unseen ambient configurations is experimentally assessed in challenging conditions, comprising external test scenarios collected in home environments that are not included in the training set. Experimental results suggest that the system can effectively generalize acquired knowledge to novel smart-home setups, thereby delivering an higher level of personalization while decreasing costs for installation and setup
Limb Movements Classification Using Wearable Wireless Low-Cost Transceivers
Full text linkA feasibility study, where small wireless transceivers
are used to classify some typical limb movements used in physical
therapy processes is presented. Wearable wireless low-cost commercial
transceivers operating at 2.4GHzare supposed to bewidely
deployed in indoor settings and on people’s bodies in tomorrow’s
pervasive computing environments. The key idea of this work is
to exploit their presence by collecting the received signal strength
measured between those worn by a person. The measurements are
used to classify a set of kinesiotherapy activities. The collected data
are classified by using both support vector machine and K-nearest
neighbor methods, in order to recognise the different activities
Reservoir Computing Forecasting of User Movements from RSS Mote-Class Sensors Measurement
No full textReal-time, indoor user localization, although limited to the current user position, is of great practical importance in many Ambient Assisted Living (AAL) applications.
Moreover an accurate prediction of the user next position (even with a short advice) may open a number of new AAL applications that could timely provide the right services in the right place even before the user request them.
However, the problem of forecasting the user position is complicated due to the intrinsic difficulty of localization in indoor environments, and to the fact that different paths of the user may intersect at a given point, but they may end in different places.
We tackle with this problem by modeling the localization information stream obtained from a Wireless Sensor Network (WSN) using Recurrent Neural Networks implemented as efficient Echo State Networks (ESNs),
within the Reservoir Computing paradigm.
In particular, we have set up an experimental test-bed in which the WSN produces localization information of a user that moves along a number of different paths, and in which the ESN collects localization information to predict a future position of the user at some given mark points.
Our results show that, with an appropriate configuration of the ESN, the system reaches a good accuracy of the prediction also with a small WSN, and that the accuracy scales well with the WSN size. Furthermore, the accuracy is also reasonably robust to variations in the deployment of the sensors. For these reason our solution can be configured to meet the desired trade-off between cost and accuracy
Allocating data for broadcasting over wireless channels subject to transmission errors
No full textBroadcasting is an efficient and scalable way of
transmitting data over wireless channels to an unlimited
number of clients. In this paper the problem of allocating
data to multiple channels is studied, assuming flat data
scheduling per channel and the presence of unrecoverable
channel transmission errors. The objective is that of minimizing
the average expected delay experienced by the
clients. Two different channel error models are considered:
the Bernoulli model and the simplified Gilbert–Elliot one.
In the former model, each packet transmission has the same
probability to fail and each transmission error is independent
from the others. In the latter one, bursts of erroneous
or error-free packet transmissions due to wireless fading
channels are modeled. Particular cases are detected where
optimal solutions can be found in polynomial time. For
general cases, simulations show that good sub-optimal
solutions can be found on benchmarks whose item popularities
follow Zipf distributions
Quality-of-service of data broadcasting on erroneous wireless channels
No full textBroadcasting is an efficient and scalable way of transmitting data over wireless channels to an unlimited number of clients. In this chapter the problem of allocating data to multiple channels is studied, assuming flat data scheduling per channel and the presence of unrecoverable channel transmission errors. The behavior of wireless channels is described by the Bernoulli model, in which each packet transmission has the same probability to fail and each transmission error is independent from the others. The objective is that of minimizing the average expected delay experienced by the clients. Optimal solutions can be found in polynomial time when all data items have unit lengths, while heuristics are presented when data items have non-unit lengths. Extensive simulations, performed on benchmarks whose item popularities follow Zipf distributions, show that good sub-optimal solutions are found
Automatic multimedia session migration by means of a context-aware mobility framework
No full textThe availability of a large number of personal, wireless multimedia devices enables the users to benefit multimedia content while moving. A further enhancement is given by the availability of context information (in terms of users' location, environment, etc.) that enables the adaptation of the multimedia content to the context and to the availability of alternative renderers. In this paper, we propose a context-aware mobility framework that supports context-dependent, multimedia interactive applications. This framework manages mobility of multimedia sessions by introducing the concept of Personal Address, that is a network identifier assigned to users and their sessions. The mobility framework also leverages on the concept of context server to interact with heterogeneous context sources on a wide area network. We describe the implementation of this framework for Voice-over-IP sessions and we report the performance results
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
- …
