Alessio Martinelli

Flexible heterogeneous satellite-based architecture for enhanced quality of life applications

The future pervasive communication ecosystem can improve and enhance the quality of our everyday lives by increasing comfort and safety perception, and improving interaction and conditions of activities: remarkable quality and performance will be afforded by the synergistic use of communication, positioning, and monitoring techniques, provided by means of meshed heterogeneous architectures based on satellite and terrestrial segments. In such a scenario satellite communication will represent the missing link of the evolution of services. This article aims to describe a flexible architecture that could be adopted in the future system and discussing the open points in the development of the system as well as of its single building blocks.

Effect of Direction and Tension of Kinesio Taping Application on Sensorimotor Coordination

The present study investigates whether different directions and tensions of Kinesio(®) Tex tape (KT) application differently influence the precision of sensorimotor synchronization, defined as the ability to coordinate actions with predictable external events. 10 healthy participants performed sets of repetitive wrist flexion-extensions synchronized to a series of paced audio stimuli with an inter-onset interval (IOI) of 500 and 400 ms. KT was applied over the wrist and finger extensor muscles. 2 facilitatory (light and moderate tension) and one inhibitory KT applications were used in different sessions. Standard deviation of the asynchrony (SDasy) and percentage difference of SDasy were calculated and compared across KT and the no-KT control cases. Direction and tension of KT application did not differently influence the ability to coordinate rhythmic movements to an auditory stimulus. However, compared with the no-KT control case, SDasy decreased significantly in all KT cases in both 500- and 400-ms IOI. Independent of direction/tension, the effect of KT on improving sensorimotor synchronization is likely associated with variations in the nature of the neuro-anatomical constraints determining the control of voluntary movement. KT is then proposed to be tested on sensorimotor disorders associated with intense repetitive exercise to check for regaining effective motor control.

Cooperative GPS positioning with peer-to-peer time assistance

In this work, a peer-to-peer cooperative positioning technique is presented, implemented and tested. Cooperation between two Global Positioning System (GPS) software-defined receivers is realized by resorting to an ad-hoc WLAN. The performance of aided acquisition and positioning algorithms with fine and coarse time assistance is evaluated. The fine time assistance is achieved by an ideal off-line synchronization technique, while the coarse time one is carried out by means of Network Time Protocol (NTP).

Peer-to-peer cooperation for GPS positioning

Summary This paper presents a peer-to-peer cooperative positioning technique together with its performance assessment. The cooperation between the two GPS receivers is realized by means of a wireless LAN connection and is significantly influenced by the accurateness of the synchronization between the two terminals. Both the outdoor-to-indoor and outdoor-to-outdoor scenarios are considered. For each scenario, we assess the satellite signal acquisition and its computational load and the performance in terms of position accuracy and time-to-first-fix of the positioning procedure. Copyright

Daily movement recognition for Dead Reckoning applications

In the last years, Activity Recognition (AR) has drawn the attention of many researchers in several fields such as user mobility identification and monitoring of patients and of daily activities. In the context of Dead Reckoning (DR) navigation systems, AR has been used so far to get landmarks on the map of the buldings and permit the calibration of the considered routines. The present work aims at providing a contribution to the definition of a more effective recognition of movement in the DR applications. To this aim we describe the implementation of a Movement Segmentation procedure which permits to distinguish between posture change movements, such as lying down and standing up, and cyclic movements such as walking, walking downstairs and upstair. As it is known, these movements which are very similar and prone to critical recognition analysis, can often be misleaded; therefore, they are considered as inputs of a supervised learning technique which allows their classification. Particularly, the acceleration data are acquired from a Motion Node sensor that is worn on front right-hip and four supervised learning classification families, namely the Decision Tree (DT), the Support Vector Machine (SVM), the K-Nearest Neighbor (KNN) and the Ensamble Learner (EL), are tested. The accuracy of the considered classification models is evaluated; particularly, the confusion matrices are presented which shed light on the collection of the movements that are more likely to be mixed up.

P2P cooperative GPS positioning with fine/coarse time assistance

In this paper, a peer-to-peer cooperative algorithm with fine/coarse time acquisition and positioning has been implemented on GPS software-defined receivers. The benefits of the aiding information are considered. Moreover, experimental results evaluate the computational and accuracy performance in the acquisition and positioning processes, respectively.

When Non-Dominant Is Better than Dominant: Kinesiotape Modulates Asymmetries in Timed Performance during a Synchronization-Continuation Task

There is a growing consensus regarding the specialization of the non-dominant limb (NDL)/hemisphere system to employ proprioceptive feedback when executing motor actions. In a wide variety of rhythmic tasks the dominant limb (DL) has advantages in speed and timing consistency over the NDL. Recently, we demonstrated that the application of Kinesio® Tex (KT) tape, an elastic therapeutic device used for treating athletic injuries, improves significantly the timing consistency of isochronous wrist’s flexion-extensions (IWFEs) of the DL. We argued that the augmented precision of IWFEs is determined by a more efficient motor control during movements due to the extra-proprioceptive effect provided by KT. In this study, we tested the effect of KT on timing precision of IWFEs performed with the DL and the NDL, and we evaluated the efficacy of KT to counteract possible timing precision difference between limbs. Young healthy subjects performed with and without KT (NKT) a synchronization-continuation task in which they first entrained IWFEs to paced auditory stimuli (synchronization phase), and subsequently continued to produce motor responses with the same temporal interval in the absence of the auditory stimulus (continuation phase). Two inter-onset intervals (IOIs) of 550-ms and 800-ms, one within and the other beyond the boundaries of the spontaneous motor tempo, were tested. Kinematics was recorded and temporal parameters were extracted and analyzed. Our results show that limb advantages in performing proficiently rhythmic movements are not side-locked but depend also on speed of movement. The application of KT significantly reduces the timing variability of IWFEs performed at 550-ms IOI. KT not only cancels the disadvantages of the NDL but also makes it even more precise than the DL without KT. The superior sensitivity of the NDL to use the extra-sensory information provided by KT is attributed to a greater competence of the NDL/hemisphere system to rely on sensory input. The findings in this study add a new piece of information to the context of motor timing literature. The performance asymmetries here demonstrated as preferred temporal environments could reflect limb differences in the choice of sensorimotor control strategies for the production of human movement.

Daily Living Movement Recognition for Pedestrian Dead Reckoning Applications

Nowadays, activity recognition is a central topic in numerous applications such as patient and sport activity monitoring, surveillance, and navigation. By focusing on the latter, in particular Pedestrian Dead Reckoning navigation systems, activity recognition is generally exploited to get landmarks on the map of the buildings in order to permit the calibration of the navigation routines. The present work aims to provide a contribution to the definition of a more effective movement recognition for Pedestrian Dead Reckoning applications. The signal acquired by a belt-mounted triaxial accelerometer is considered as the input to the movement segmentation procedure which exploits Continuous Wavelet Transform to detect and segment cyclic movements such as walking. Furthermore, the segmented movements are provided to a supervised learning classifier in order to distinguish between activities such as walking and walking downstairs and upstairs. In particular, four supervised learning classification families are tested: decision tree, Support Vector Machine, -nearest neighbour, and Ensemble Learner. Finally, the accuracy of the considered classification models is evaluated and the relative confusion matrices are presented.

The Less You are, the More You are Helped: Effect of Kinesio Tape on Temporal Coordination

We investigated whether a relationship exists between the inherent timing skill of subject and the magnitude of effect of KT on timing performance by expanding the examination of the dataset described in our previous work. Healthy subjects, tested with and without KT (NKT), performed sets of repetitive wrists flexion-extensions (IWFEs) with the dominant limb (DL) and the non-dominant limb (NDL) in a synchronization-continuation task at two inter-onset intervals (IOIs): 550-ms and 800-ms. Standard deviation (SD) of IWFEs was used to measure the unevenness of performance. Different patterns of response to KT were observed based on the participants inherent precision. In the NDL the effect of KT was found significantly higher in the subgroups of individuals having SDNKT of IWFEs>38 ms (p=0.0024) in the 800-ms IOI or SDNKT of IWFEs>19 ms (p=0.0004) in the 550-ms IOI. In the DL the effect of KT was not influenced by the inherent timing skill. We propose KT to be tested for restoring motor control on subjects experiencing sensorimotor disorders associated with intense repetitive training. Also, our findings suggest that care should be taken when using groups of healthy subjects to test the effect of KT.

Probabilistic Context-aware Step Length Estimation for Pedestrian Dead Reckoning

This paper introduces a weighted context-based step length estimation algorithm for pedestrian dead reckoning. Six pedestrian contexts are considered: stationary, walking, walking sideways, climbing and descending stairs, and running. Instead of computing the step length based on a single context, the step lengths computed for different contexts are weighted by the context probabilities. This provides more robust performance when the context is uncertain. The proposed step length estimation algorithm is part of a pedestrian dead reckoning system which includes the procedures of step detection and context classification. The step detection algorithm detects the step time boundaries using continuous wavelet transform analysis, while the context classification algorithm determines the pedestrian context probabilities using a relevance vector machine. In order to assess the performance of the pedestrian dead reckoning system, a data set of pedestrian activities and actions has been collected. Fifteen subjects have been equipped with a waist-belt smartphone and traveled along a predefined path. Acceleration, angular rate and magnetic field data were recorded. The results show that the traveled distance is more accurate using step lengths weighted by the context probabilities compared to using step lengths based on the highest probability context.