Analysis of Android Device-Based Solutions for Fall Detection

Falls are a major cause of health and psychological problems as well as hospitalization costs among older adults. Thus, the investigation on automatic Fall Detection Systems (FDSs) has received special attention from the research community during the last decade. In this area, the widespread popularity, decreasing price, computing capabilities, built-in sensors and multiplicity of wireless interfaces of Android-based devices (especially smartphones) have fostered the adoption of this technology to deploy wearable and inexpensive architectures for fall detection. This paper presents a critical and thorough analysis of those existing fall detection systems that are based on Android devices. The review systematically classifies and compares the proposals of the literature taking into account different criteria such as the system architecture, the employed sensors, the detection algorithm or the response in case of a fall alarms. The study emphasizes the analysis of the evaluation methods that are employed to assess the effectiveness of the detection process. The review reveals the complete lack of a reference framework to validate and compare the proposals. In addition, the study also shows that most research works do not evaluate the actual applicability of the Android devices (with limited battery and computing resources) to fall detection solutions.Ministerio de Economía y Competitividad TEC2013-42711-

A characterization of the performance of Bluetooth 2.x + EDR technology in noisy environments

Bluetooth (BT) is by far the most popular shortrange technology for the development of wireless personal area networks and body area networks. Nowadays, BT 2.0 and 2.1 ? EDR are the most extended and implemented versions of BT standard. This article presents an analytical model that computes the packet delay of transmissions that utilize this version of BT in noisy environments. The model, which takes into account the packet retransmissions caused by noise, is particularized to calculate the mean packet delay as a function of the signal-to-noise ratio for the different enhanced data rates provided by BT 2.0 and 2.1 specifications. Thus, the model permits evaluating the efficiency of using these enhanced rates in the presence of a certain noise level.Ministerio de Ciencia e Innovación TEC2009-13763-C02-01Ministerio de Ciencia e Innovación TEC2013-42711-

On the Capability of Smartphones to Perform as Communication Gateways in Medical Wireless Personal Area Networks

This paper evaluates and characterizes the technical performance of medical wireless personal area networks (WPANs) that are based on smartphones. For this purpose, a prototype of a health telemonitoring system is presented. The prototype incorporates a commercial Android smartphone, which acts as a relay point, or “gateway”, between a set of wireless medical sensors and a data server. Additionally, the paper investigates if the conventional capabilities of current commercial smartphones can be affected by their use as gateways or “Holters” in health monitoring applications. Specifically, the profiling has focused on the CPU and power consumption of the mobile devices. These metrics have been measured under several test conditions modifying the smartphone model, the type of sensors connected to the WPAN, the employed Bluetooth profile (SPP (serial port profile) or HDP (health device profile)), the use of other peripherals, such as a GPS receiver, the impact of the use of theWi-Fi interface or the employed method to encode and forward the data that are collected from the sensors.Ministerio de Educación y Ciencia TEC2009-13763-C02-0

Analytical Characterisation of the Performance of Bluetooth Piconets Using Serial Port Profile

Bluetooth is a key connectivity technology for the deployment of wireless Personal Area Networks as far as it is the most popular low power communication feature incorporated in devices such as laptops or smartphones. This paper proposes an analytical model to predict the delay of the transmissions in Bluetooth piconets employing Serial Port Profile (SPP), which is massively implemented by Bluetooth-enabled equipments. The characterization includes the impact of the overhead and the segmentation imposed by the different protocols involved in the transmission as well as the delay provoked by the polling process that is executed to regulate the activity of the different slaves in the piconet. The model has been empirically evaluated and tested in an actual Bluetooth piconet.Ministerio de Educación y Ciencia TEC2009-13763-C02-0

Analytical Characterization of the Lowest Delay Bound in Bluetooth 2.0+EDR Transmissions

This paper presents an analytical model to compute the minimum delay of Bluetooth 2.0 transmissions. The model, which is focused on connections using Serial Port Profile (SPP), characterizes in detail the effects of employing the Enhanced Date Rates introduced by the new version of the standard, which is widely implemented in most commercial Bluetooth interfaces. The model has been empirically evaluated in a real piconet.Ministerio de Educación y Ciencia TEC2009-13763-C02-0

Highly active catalytic Ru/TiO2 nanomaterials for continuous production of γ-valerolactone

Green energy production from renewable sources is an attractive but challenging topic to face the likely energy crisis scenario in the future. In the current work, a series of versatile Ru/TiO2 catalysts were simply synthesized and employed in continuous flow catalytic transfer hydrogenation of industrially derived methyl levulinate biowaste (from Avantium Chemicals B.V.) to γ-valerolactone. Different analytical techniques were applied in the characterization of the as-synthesized catalysts, including XRD, SEM, EDX, TEM and XPS etc. The effects of various reaction conditions (e.g. temperature, concentration and flow rate) were investigated. Results suggested that optimum dispersion and distribution of Ru on the TiO2 surface could efficiently promote production of γ-valerolactone, with 5% Ru/TiO2 catalyst providing excelling catalytic performance and stability as compared to commercial Ru catalysts