Pedro J. Fernández

Is There a Specific Pattern of Attention Deficit in Mild Cognitive Impairment with Subcortical Vascular Features? Evidence from the Attention Network Test

Background: Mild cognitive impairment (MCI) is an intermediate state between normal aging and early dementia. Some MCI patients show white matter hyperintensities in magnetic resonance imaging, revealing subcortical vascular damage (SVD). This study aimed to evaluate potential attention deficits not previously described in these patients. Specifically, we evaluated attention network functioning in MCI on the basis of Posner’s cognitive neuroscience model, which considers attention as a set of networks: alerting, orienting and executive control. Methods: Three groups of participants were tested: 19 MCI patients with SVD (svMCI), 15 MCI patients free from SVD (nvMCI) and 19 healthy controls (HC). We used a task in which the three attention networks and their interactions can be assessed simultaneously, the Attention Network Test (ANT). Results: The svMCI group showed smaller orienting effect compared with the nvMCI and HC groups. In contrast to the HC and nvMCI groups, svMCI patients did not show improvement in the executive network from the valid visual cue. Conclusions: svMCI patients show a deficit in orienting attention networks. This deficit could be related to an effect of SVD on the cholinergic system because acetylcholine is implicated in the modulation of covert orienting responses of attention.

Attention Network Functioning in Patients with Dementia with Lewy Bodies and Alzheimer’s Disease

Background: Attention deficits are at the core of the defects in neuropsychological performance which define both dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD). Most studies have used separate tasks to test different attention abilities in patients with these diagnoses, precluding the assessment of any interaction among the different attention components. Methods: We used a version of the Attention Network Test in which the alerting, orienting and executive attention networks, along with their interactions, could be assessed with a single task. Three groups of participants were tested: DLB patients (n = 13), AD patients (n = 18) and healthy controls (n = 18). Results: The alerting signal improved orienting attention and increased the conflict effect in the healthy controls, but they had no effect on these networks in the AD patients. The DLB patients only showed preserved orienting and conflict effects when the alerting signal was present, indicating that there was regulation of the orienting and executive attention networks by the alerting signal. Conclusions: The most important differences among the 3 groups were observed in the attention network interactions, where alerting played a more relevant role in the DLB than in the AD patients. Under alerting states, the DLB patients showed evidence of certain regulation in the orienting and executive attention networks.

A Framework for Supporting Network Continuity in Vehicular IPv6 Communications

The appearance of recent standards about cooperative ITS architectures towards a reference communication stack has been an inflection point in the research about vehicular networks. The ISO Communication Access for Land Mobiles (CALM) and the ETSI European ITS communication architecture have paved the way towards real and interoperable vehicular cooperative systems. Within these convergent proposals, IPv6 communications are recognized as a key component to enable traffic efficiency and infotainment applications. The proper operation of these applications and the achievement of value-added ITS services require an uninterrupted network connectivity. This paper addresses this problem by proposing a novel communication stack to support the provision of continuous and secure IPv6 vehicular communications. The solution follows the ISO/ETSI guidelines for the development of cooperative ITS systems and is based on standardized technologies such as Network Mobility (NEMO) protocol to provide an integral management of IPv6mobility. The solution integrates IEEE 802.21 media independent handover services for optimizing the handover process. While the support to the handover optimization offered by the proposed ITS communication stack is demonstrated through a mobility use case, a real testbed supporting most of the communications features is developed to validate and assess the real performance of the stack design.

Securing Vehicular IPv6 Communications

A common practice is applying security after a network has been designed or developed. We have the opportunity of not committing this error in vehicular networks. Apart from particular works in the literature, ETSI TC ITS has defined general security services for (vehicular) cooperative systems. However, existent efforts do not pay the needed attention to the integration of IPv6 yet. The potential of IPv6 in the field is being described within ISO TC 204, above all, but further work is needed for a proper integration of security. This work follows this direction, and a reference vehicular communication architecture considering ETSI/ISO regulations, uses Internet Protocol security (IPsec) and Internet Key Exchange version 2 (IKEv2) to secure IPv6 Network Mobility (NEMO). A key advance is also the implementation and experimental evaluation of the proposal in a challenging vertical handover scenario between 3G and 802.11p. The performance of the secured NEMO channel is widely analyzed in terms of the movement speed, bandwidth, traffic type or signal quality, and it is concluded that the addition of IPv6 security only implies a slight reduction in the overall performance, with the great advantage of providing confidentiality, integrity and authenticity to the communication path.

IPv6 Communication Stack for Deploying Cooperative Vehicular Services

New-age cooperative services for vehicles involve communication nodes in nomadic devices, vehicles, roads and central stations. However, as the number of vehicular services hosted in both the vehicle and infrastructure side increase, it is more and more necessary to use a proper framework to deploy them effectively using a common interconnection network. Following the ISO/ETSI recommendations, which provide a reference ITS communication architecture, the current work provides an implementation, deployment and experimental assessment of a vehicular communications stack for providing infrastructure-to-vehicle services. The architecture presented in this paper considers open issues such as communications security, the support of geo-referenced facilities, the need of a service deployment framework in vehicles and central stations, and the management of host software.

A vehicular network mobility framework: Architecture, deployment and evaluation

Research on vehicular networks has increased for more than a decade, however, the maturity of involved technologies has been recently reached and standards/specifications in the area are being released these days. Although there are a number of protocols and network architecture proposals in the literature, above all in the Vehicular Ad-hoc Network (VANET) domain, most of them lack from realistic designs or present solutions far from being interoperable with the Future Internet. Following the ISO/ETSI guidelines in field of (vehicular) cooperative systems, this work addresses this problem by presenting a vehicular network architecture that integrates well-known Internet Engineering Task Force (IETF) technologies successfully employed in Internet. More precisely, this work describes how Internet Protocol version 6 (IPv6) technologies such as Network Mobility (NEMO), Multiple Care-of Address Registration (MCoA), IP Security (IPsec) or Internet Key Exchange (IKE), can be used to provide network access to in-vehicle devices. A noticeable contribution of this work is that it not only offers an architecture/design perspective, but also details a deployment viewpoint of the system and validates its operation under a real performance evaluation carried out in a Spanish highway. The results demonstrate the feasibility of the solution, while the developed testbed can serve as a reference in future vehicular network scenarios.

Cooperative ITS for two-wheel vehicles to improve safety on roads

Research efforts carried out on Intelligent Transportation Systems (ITS) for improving safety and efficiency of road transportation have been focused on cars, where vehicular communications have demonstrated to enhance the driver awareness with active services that improve fatality statistics. Although common vehicles accidents have been reduced in the last years, those involving vulnerable road users remain. Cyclists and motorcyclists cover a whole area where ITS and telematics should be embedded with no doubt, given the incremental popularity of bikes and motorbikes in urban mobility and short interurban routes. For this reason, this work takes the key objective of integrating two-wheelers within the future cooperative ITS network. Hence, a novel communication device especially adapted to cyclists and motorcyclists has been designed, by integrating vehicular wireless communications (i.e. IEEE 802.11p) and considering interface limitations. From the protocols perspective the work is focused on IPv6, and considers two-wheelers as part of the Future Internet. In fact, a great success of the proposal is exploiting the synergy between IETF (Internet) and ITS-specific protocols coming from ISO and ETSI, creating a novel active system to improve two-wheel transport safety through Cooperative Awareness Messaging (CAM) over IPv6. The embedded communication node for two-wheelers includes the proper software to warn the driver about the approaching of a regular vehicle through audio and visual notifications. Moreover, its counterpart for common cars has also been developed, but using an Android application running on a handheld device connected to a regular IPv6 in-vehicle network.

Deployment of vehicular networks in highways using 802.11p and IPv6 technologies

Most of the previous and current vehicular communication deployments, testbeds and, in general, experimental efforts come from research contributions evaluating particular solutions in the area. We have had to wait until recent days to see great testing campaigns in vehicular cooperative systems, coming from research projects supported by national or international funding. This paper reviews the deployment and operation of communication infrastructures in one of the major European projects in this area, i.e., European field operational test on safe, intelligent and sustainable road operation FOTsis. A key advance of FOTsis has been the integration of IEEE 802.11p and IPv6 technologies following the ISO/ETSI guidelines in cooperative systems for vehicle to infrastructure V2I communications. This work reports our main findings providing an interoperable IPv6 access to vehicular services, describes the main test-sites, provides vehicular network performance tests, and summarises our experience in these deployments. Our recommendations pave the way for future large-scale vehicular communication deployments in the V2I segment, which is expected to be the most relevant in the short and medium term.

Evaluation Framework for IEEE 802.15.4 and IEEE 802.11 for Smart Cities

Jemula802 is a simulator developed by Disney Research for the standard IEEE 802.11, more specifically 802.11a/g. Jemula802 is used for simulations on scenarios related with Theme Park deployments. This paper describes the progress of the design and implementation of the IEEE 802.15.4 over Jemula. Jemula802.15.4-adaptation transforms Jemula802 (simulator of IEEE 802.11 standard) into the IEEE 802.15.4 standard simulator. IEEE 802.15.4, standard for low-rate wireless personal area networks (LR-WPANs) that specifies the physical layer and medium access control that is the base for upper layer protocols like Zigbee, MiWi and WirelessHART. Thereby, Jemula is offering a simulator and emulation framework to evaluate and compare deployments based on IEEE 802.11 (WiFi) and IEEE 802.15.4 (Wireless Sensor Networks). In addition, Jemula offers the visualization libraries for theme parks that can be also applied for smart cities. Therefore, Jemula can be considered as a evaluation framework for IEEE 802.15.4 and IEEE 802.11 for Smart Cities.

Offloading Positioning onto Network Edge

While satellite or cellular positioning implies dedicated hardware or network infrastructure functions, indoor navigation or novel IoT positioning techniques include flexible storage and computation requirements that can be fulfilled by both end-devices or cloud back-ends. Hybrid positioning systems support the integration of several algorithms and technologies; however, the common trend of delegating position calculation and storage of local geoinformation to mobile devices or centralized servers causes performance degradation in terms of delay, battery usage, and waste of network resources. The strategy followed in this work is offloading this computation effort onto the network edge, following a Mobile Edge Computing (MEC) approach. MEC nodes in the access network of the mobile device are in charge of receiving navigation data coming from both the smart infrastructure and mobile devices, in order to compute the final position following a hybrid approach. With the aim of supporting mobility and the access to multiple networks, an Information Centric Networking (ICN) solution is used to access generic position information resources. The presented system currently supports WiFi, Bluetooth LE, GPS, cellular and NFC technologies, involving both indoor and outdoor positioning, using fingerprinting and proximity for indoor navigation, and the integration of smart infrastructure data sources such as the door opening system within real smart campus deployment. Evaluations carried out reveal latency improvements of 50%, as compared with a regular configuration where position fixes are computed by mobile devices; at the same time the MEC solution offers extra flexibility features to manage positioning databases and algorithms and move extensive computation from constrained devices to the edge.