Mobile Links Research Articles

88 Streaming High-Fidelity ECMO Simulation from a Moving Ambulance

The Trust needed to offer extra-corporeal membrane oxygenation (ECMO) The aim of the study was to deliver high-fidelity ECMO simulation in a moving vehicle while simultaneously allowing candidates and faculty to watch the scenarios take place remotely.A custom video-over-IP system was used to run three camera feeds and a patient monitor output. A laptop captured this in a quad-view format and streamed it to a dedicated video streamer. This was then networked locally via a router with a secondary laptop which displayed the stream. The router was connected to a mobile 4G modem, allowing the secondary laptop to share this video stream via Microsoft Teams (MS Teams). In addition, a USB audio interface and microphones ensured intelligibility while the vehicle was in motion.Teaching groups were made up of 3–4 candidates from the ECMO team and 3–4 candidates from patient transport. Scenarios outlined a paediatric patient, currently on ECMO, being transferred to a specialist hospital in the region via ambulance. One or two candidates from each service would take part in the scenario and the remaining candidates would view the simulation in the centre debrief room. A technician in front of the ambulance controlled the simulator and monitored the streams. The lead ECMO specialist nurse spoke to the technician from the simulation centre via a mobile phone link. The role of a consultant was played by a member of the transport faculty on the ambulance. This allowed the faculty to oversee and prompt when necessary. Using MS Teams meant the stream could be shared with the debrief room at the centre, the control room, and with other interested parties outside of the centre. This created a unique learning experience where all candidates could see each scenario and play an active role in debrief when the ambulance returned to the centre. Successful delivery of this course will improve patient safety during potentially complex ECMO transfers. We hope to invite more remote participants via MS Teams to view the simulations and take part in the debrief, increasing learning opportunities for ECMO and transfer staff.

Generational differences, socialisation effects and ‘mobility links’ in international holiday travel

International holiday travel was rapidly growing until the COVID19 crisis and was widely expected to continue on such a trajectory for decades. This is consistent with long-term trends towards the expansion of activity spaces and the increasing importance of high-speed modes of travel. This would suggest that young adults today had earlier and more frequent experience of cross-border holiday travel than previous generations, with possible knock-on effects in terms of socialisation to increased international mobility. Previous research has also suggested the existence of self-reinforcing dynamics in international mobility over individual life courses and across family generations. The concept of “mobility links” points to such effects, whereby e.g., international mobility experience leads to more foreign trips later in the life course and/or in the subsequent generation. Robust quantitative evidence of such trends and associations, however, has remained elusive due to the lack of adequate data. We use unique data from Dortmund (Germany) including detailed retrospective information on holiday travel and life course events for a large sample of students, their parents, and grandparents. Our results show: i) a rapidly increasing trend in international holiday travel behaviour (trip frequency and age at first trip) across three generations; ii) from a socialisation perspective, associations between international holiday frequency and age at first holiday abroad among students; iii) from an intergenerational perspective, associations between the holiday practices of students and their parents. We conclude by discussing implications for further research on mobility biographies and the ‘institutionalisation’ of international travel, as well as policy implications.

Simplified Coherent Receiver for Analogue Radio Transmission Over High Optical Budgets

The bandwidth and latency demands driven by 5G wireless networks are putting a focus on analog radio-over-fiber techniques as a promising candidate for broadband optical fronthauling. In contrast to intensity modulation / direct detection systems, as they are commonly adopted for mobile fronthaul links due to their simplicity, we are exploring a migration option towards coherent radio-over-fiber transmission. A simplified coherent homodyne receiver based on an electro-absorption modulated laser is co-integrated at the die-level with a transimpedance amplifier and evaluated for analogue coherent radio-over-fiber transmission. This low-complexity homodyne receiver can unlock channel selectivity and high receiver sensitivity inherent to coherent detection, but without the need for digital signal processing. We will demonstrate a sensitivity that allows for an optical budget of 42 dB, and thus eases the fixed-mobile convergence in power-splitting fiber plants. We further show filterless radio signal reception in presence of modulated adjacent channels. Signal integrity is confirmed through transmission of orthogonally frequency multiplexed radio signals with 16-point quadrature amplitude modulated formats, with an error vector magnitude below the corresponding antenna limit.

Seed traits matter-Endozoochoric dispersal through a pervasive mobile linker.

Although many plants are dispersed by wind and seeds can travel long distances across unsuitable matrix areas, a large proportion relies on co‐evolved zoochorous seed dispersal to connect populations in isolated habitat islands. Particularly in agricultural landscapes, where remaining habitat patches are often very small and highly isolated, mobile linkers as zoochorous seed dispersers are critical for the population dynamics of numerous plant species. However, knowledge about the quali‐ or quantification of such mobile link processes, especially in agricultural landscapes, is still limited. In a controlled feeding experiment, we recorded the seed intake and germination success after complete digestion by the European brown hare (Lepus europaeus) and explored its mobile link potential as an endozoochoric seed disperser. Utilizing a suite of common, rare, and potentially invasive plant species, we disentangled the effects of seed morphological traits on germination success while controlling for phylogenetic relatedness. Further, we measured the landscape connectivity via hares in two contrasting agricultural landscapes (simple: few natural and semi‐natural structures, large fields; complex: high amount of natural and semi‐natural structures, small fields) using GPS‐based movement data. With 34,710 seeds of 44 plant species fed, one of 200 seeds (0.51%) with seedlings of 33 species germinated from feces. Germination after complete digestion was positively related to denser seeds with comparatively small surface area and a relatively slender and elongated shape, suggesting that, for hares, the most critical seed characteristics for successful endozoochorous seed dispersal minimize exposure of the seed to the stomach and the associated digestive system. Furthermore, we could show that a hare's retention time is long enough to interconnect different habitats, especially grasslands and fields. Thus, besides other seed dispersal mechanisms, this most likely allows hares to act as effective mobile linkers contributing to ecosystem stability in times of agricultural intensification, not only in complex but also in simple landscapes.

Social Mobility and Spatialised Slowness

Abstract This article analyses the individual aspirations of Sierra Leoneans living in France in relation to normative expectations related to mobility. It argues that aspirations and expectations are expressions of spatialized forms of social becoming situated within broader norms concerning socially-valued forms of mobility. Aspirations to social mobility link up distinct places in a fragmented transnational field, transform them as value-laden spaces, and inform migrants’ assessment of their own trajectory within them. Individual aspirations are formulated with regard to spaces migrants have left, spaces they live in, and spaces they would like to reach. Sierra Leoneans living in France have reached a ‘destination country’ and yet, do not experience their situation as the ideal migratory path. Their achievements are measured with regard to expectations of social mobility as imagined in English-speaking spaces, thereby reinforcing the narrative of mobility and the persistence of local idioms of ‘success’ based on historical transnational connections.

An optimized mobile similarity and link transmission quality routing protocol for urban VANETs

An optimized mobile similarity and link transmission quality routing protocol for urban VANETs

Video streaming over IoV using IP multicast

Video traffic over Internet of vehicles is increasing day by day to provide passengers on-board infotainment services. A video streaming service over Internet of vehicles involves design challenges of vehicular gateway selection, and vehicle to vehicle collaboration. Vehicular gateway selection is challenging due to high vehicle mobility and time-varying link conditions. Existing works on vehicular gateway selection focus on either service cost minimization, or quality of experience. To achieve a balance between these two aspects, we propose a novel vehicular gateway selection protocol that minimizes streaming service cost, keeping end-to-end delivery delay as a constraint. In our work, the vehicular gateway selection problem is formulated centrally as the minimum set-covering problem, and is solved by the greedy approximation method. In existing works, vehicle to vehicle collaboration happens in the application layer ignoring the presence of network layer nodes which do not run any proprietary application. To make the vehicle to vehicle collaboration in the network layer, we propose a novel multicast protocol SS-CAST specifically designed for streaming service over vehicular networks. Compared to existing protocols, the simulation results show VSIM as the clear winner for minimizing service cost while giving a competitive performance in the quality of experience metrics.

Mobile link prediction: Automated creation and crowdsourced validation of knowledge graphs

Building trustworthy knowledge graphs for cyber–physical social systems (CPSS) is a challenge. In particular, current approaches relying on human experts have limited scalability, while automated approaches are often not validated by users resulting in knowledge graphs of questionable quality. This paper introduces a novel pervasive knowledge graph builder for mobile devices that brings together automation, experts’ and crowdsourced citizens’ knowledge. The knowledge graph grows via automated link predictions using genetic programming that are validated by humans for improving transparency and calibrating accuracy. The knowledge graph builder is designed for pervasive devices such as smartphones and preserves privacy by localizing all computations. The accuracy, practicality, and usability of the knowledge graph builder is evaluated in a real-world social experiment that involves a smartphone implementation and a Smart City application scenario. The proposed methodology of knowledge graph building outperforms a baseline method in terms of accuracy while demonstrating its efficient calculations on smartphones and the feasibility of the pervasive human supervision process in terms of high interactions throughput. These findings promise new opportunities to crowdsource and operate pervasive reasoning systems for cyber–physical social systems in Smart Cities.

Interference-graph and fuzzy C-means based resource allocation scheme in LTE-V2V communication networks

In this paper, a framework is proposed to improve the effectiveness of the long-term-evolution vehicle-to-vehicle (LTE-V2V) communication system, where the uplink channel of the cellular user equipment (CUE) is reused by multiple V2V links. Since the orthogonal channels occupied by each CUEs are multiplexed by multiple V2V links, the serious interference is generated in the co-tier layer and cross-tier layer. In order to minimize the co-channel interference between CUE link and V2V links, an optimized resource sharing scheme is proposed. Firstly, Fuzzy C-means (FCM) algorithm is proposed to perform the clustering based on the geographical location characteristics of V2V links. In the FCM algorithm, the adjacent V2V links are grouped into a cluster to facilitate the solution of the channel allocation problem. Assuring the V2V links in the same cluster do not share the same channel, the adjacent V2V links are avoided to reuse the same channel. On this basis, the use of reasonable channel allocation scheme can effectively reduce the co-channel interference. Considering that the channel state information (CSI) of mobile links is slowly faded, the total system capacity is maximized by leveraging the CSI while the reliability can be guaranteed for all V2V links. The outage probability constraint is used to ensure the reliability of all V2V links. The channel assignment problem of V2V links is formulated as a weighted two-dimensional matching problem, and the interference bipartite graph is constructed. Finally, Kuhn Munkras (KM) algorithm is introduced to allocate the uplink orthogonal channel of CUEs for the V2V links in the same class in order to maximize the total system capacity. Numerical simulation results show that the algorithm can improve the total system capacity.

Terahertz Wireless Communications: Co-Sharing for Terrestrial and Satellite Systems Above 100 GHz

This letter demonstrates how spectrum up to 1 THz will support mobile communications beyond 5G in the coming decades. Results of rooftop surrogate satellite/tower base station measurements at 140 GHz show the natural isolation between terrestrial networks and surrogate satellite systems, as well as between terrestrial mobile users and co-channel fixed backhaul links. These first-of-their-kind measurements and accompanying analysis show that by keeping the energy radiated by terrestrial emitters on the horizon (e.g., elevation angles ≤ 15°), there will not likely be interference in the same or adjacent bands between passive satellite sensors and terrestrial terminals, or between mobile links and terrestrial backhaul links at frequencies above 100 GHz.

Making ways for ‘better education’: Placing the Shenzhen-Hong Kong mobility industry

Tens of thousands of children living on Mainland China cross the border between Shenzhen and Hong Kong for a ‘better education’ every day. A well-oiled industry is in place to manage, facilitate and control this education mobility field. It involves schools, diverse businesses and non-governmental organisations that, in articulation with the Chinese and Hong Kong states, stimulate and regulate the movement of people, materialities, ideas and practices. Drawing on our fieldwork and media analysis, this paper unpacks the transurban mobility industry to illustrate the role of the various players and how they work in conjunction to facilitate cross-border schooling, especially among the very young children. We map out and visualise with photos the workings of the schools, buses, escorts, tutoring centres, day care and boarding houses. We show how the mobility industry, intersecting with other business networks and mobility systems, links Shenzhen and Hong Kong, taking and making places in these cities, especially in the border region. Our paper illustrates the role of this mobility industry in the making of the political-economy and socio-culture of the border area, which constantly connects, divides and redefines the two cities and regions it bridges. We end with some reflections on the implications of the recent political challenges and COVID-19 pandemic on this cross-border education mobility system.

Modeling of Wireless Traffic Load in Next Generation Wireless Networks

Software defined WiFi network (SD-WiFi) is a new paradigm that addresses issues such as mobility management, load management, route policies, link discovery, and access selection in traditional WiFi networks. Due to the rapid growth of wireless devices, uneven load distribution among the network resources still remains a challenging issue in SD-WiFi. In this paper, we design a novel four-tier software defined WiFi edge architecture (FT-SDWE) to manage load imbalance through an improved handover mechanism, enhanced authentication technique, and upgraded migration approach. In the first tier, the handover mechanism is improved by using a simple AND operator and by shifting the association control to WAPs. Unauthorized user load is mitigated in the second tier, with the help of base stations (BSs) which act as edge nodes (ENs), using elliptic ElGamal digital signature algorithm (EEDSA). In the third tier, the load is balanced in the data plane among the OpenFlow enabled switches by using the whale optimization algorithm (WOA). Moreover, the load in the fourth tier is balanced among the multiple controllers. The global controller (GC) predicts the load states of local controllers (LCs) from the Markov chain model (MCM) and allocates packets to LCs for processing through a binary search tree (BST). The performance evaluation of FT-SDWE is demonstrated using extensive OMNeT++ simulations. The proposed framework shows effectiveness in terms of bandwidth, jitter, response time, throughput, and migration time in comparison to SD-WiFi, EASM, GAME-SM, and load information strategy schemes.

Amplify-and-forward relaying in mobile multi-hop molecular communication via diffusion

In this paper, we investigate amplify-and-forward (AF) relaying scheme for mobile three-dimensional (3D) multi-hop molecular communication via diffusion (MCvD) in the stochastic channel by using different type of molecules (DTM) and same type of molecules (STM) in each hop, respectively. Under the DTM scheme, both the inter-symbol interference (ISI) and the noise of each link are taken into account Compared with the DTM scheme, an additional factor should be considered for the STM scheme, which is the self-interference (SI) effect. Under DTM and STM, we derive the mathematical expressions of optimal detection thresholds at receiver node in mobile two-hop MCvD system by using the maximum-a-posterior (MAP) decision method. Then we extend the analysis to mobile multi-hop MCvD system. Furthermore, the performances of bit error probability and mutual information are evaluated via particle-based simulation of the Brownian motion. The numerical and simulation results reveal that the performance under DTM outperforms that under STM, which indicates the potential of AF relaying scheme under DTM to improve the overall performance of this system. Besides, the comparison results between mobile and static multi-hop link under DTM and STM are given. The obtained results are expected to provide guidance significance for designing mobile multi-hop MCvD system with lower bit error probability and higher mutual information.

Real-Time Air-to-Ground Data Communication Technology of Aeroengine Health Management System with Adaptive Rate in the Whole Airspace

To overcome the problem of data transmission of the aeroengine health management system, a multilink communication system combining ultrahigh-frequency communication link, 4G cellular mobile communication link, and BeiDou satellite communication link was proposed. This system can realize the functions such as data receiving and sending, data encryption, and resuming transfer from the break point based on multiple links. When the flight altitude is not high, the communication distance is short, so the UHF digital transmission radio communication link is adopted, which is highly efficient and stable. When the communication distance is long, the 4G cellular mobile communication link can ensure both the communication distance and the communication rate. In the area where 4G signal cannot be covered in extreme terrain environment, BeiDou satellite communication link is used for data transmission. Besides, in order to ensure the communication rate of the link, a multilink adaptive switching technology was also developed. The test verified that the system can perform adaptive switching among multiple links, realize air-ground data communication in the whole airspace, and achieve a good communication rate, which has significative value of engineering application.

Adaptive optics model characterizing turbulence mitigation for free space optical communications link budgets.

Free-space optical communications (FSOC) is becoming an important option for both atmospheric and space-based high data rate networks. Long-range, mobile FSOC links in the former environments must mitigate the effects of turbulence if they are to provide reliable, high link availability under cloud-free atmospheric conditions. Adaptive optics (AO) has been proposed as one means of reducing link degradation in turbulence, but field validated AO performance models are few and not definitive. These models are important if credible FSOC high performance links are expected to be deployed using AO systems. This paper reviews the Strehl ratio for the Andrews AO model and provides comparisons between predicted AO-based FSOC link budgets and measured link performance derived from several field trials. These results suggest that AO systems perform well under weak turbulence or short range under 10 km, but only offer limited tip/tilt gain in moderate turbulence and no gain under high/saturation regime turbulence at longer ranges. Long range links close to the ground in high moderate turbulence may degrade AO performance further.

How to Define a New Metropolitan Area? The Case of Quito, Ecuador, and Contributions for Urban Planning

The Metropolitan Area of Quito has experienced exponential growth in recent decades, especially in peri-urban sectors. The literature has described this process as “urban sprawl”, a phenomenon that is changing the landscape by increasing land consumption and forming conurbations with the nearest populated centers. This article proposes a new, broader and more complex metropolitan structure for the metropolis of Quito, the linking of neighboring and conurbed areas to the form a new metropolitan area based on the case study of the Metropolitan District of Quito (DMQ). This new metropolitan area identification considers the interpretation of satellite images and the classification of land uses, highlighting the main urban growth areas located outside, but contiguous to the administrative limit of the DMQ, over a period of 19 years (1998 to 2017), the demographics analysis, particularly the densification of new urban peripheral areas close to the DMQ border and the mobility links of population, goods and services between human settlements that allows the configuration of urban corridors and the integration of the territory. The main findings evaluated are the need to evaluate urban planning strategies aimed at sustainable development.

Perceptual service-level QoE and network-level QoS control model for mobile video transmission

The cumulative effects of network transmission link imperfections and real-time limitations of video data result in multiple challenges for mobile video transmission. The challenges, together with the increasing expectations of users for well-displayed videos, further extend the complexity particularly in dense areas. To address the issues and provide efficient mobile video transmission, this work proposes a model with two phases: network-related settings (NRS) and video-related settings (VRS). The NRS is related to the mobile transmission link limits and develops four separate mobile networks, including long term evolution, 802.11 ax dual-band, and 802.11 ac. The VRS, on the other hand, is related to the video real-time constraints and covers five well-known compression algorithms used in the reference video preparation process. With comprehensibility in mind, the model comprises different factors that have a profound impact on the mobile video transmission process. The model is implemented and the results determine the video delivery efficiency in terms of the network-level quality of service and service-level quality of experience. To further validate the model, a testbed is set up and the measured experimental results are compared with those of the simulation. The results establish a baseline for efficient mobile video transmission on resource constraint devices.

Improving access to health services for female entertainment workers in Cambodia: findings from the Mobile Link randomised controlled trial

BackgroundFemale entertainment workers (FEWs) in Cambodia who work at karaoke bars, massage parlours, and beer gardens have higher rates of HIV and sexually transmitted infections (STIs), psychological distress, substance use, and gender-based violence than the general population. Reaching these workers with health education and services has been difficult because of their hidden and stigmatised status. This study evaluates the Mobile Link intervention, which aims to engage FEWs in Cambodia by connecting them to existing services for HIV, sexual and reproductive health, and gender-based violence using short message services and voice messages to ultimately improve their health. MethodsThe Mobile Link intervention consisted of text or voice messages on ten health topics, which were delivered twice a week for 10 weeks and the message topics were repeated every 10 weeks for 30 weeks (time 2) and 60 weeks (time 3). The messages were co-developed with FEWs over a 6-month period before the trial began. We used a stratified random sampling method to select 600 FEWs from a list of 4000 by age group (18–24 years old and 25–30 years old) and study sites (two sites in Phnom Penh and one site each in Battambang, Banteay Meanchey, and Siem Reap). Participants were randomly allocated to the intervention or standard-care control group. Primary outcome measures were self-reported HIV and STI testing, condom use, and contraceptive use. Secondary outcomes included contact with outreach workers, use of escorted referral services, forced drinking and gender-based violence. Intervention effects were modelled using repeated-measures multilevel mixed-effects logistic regression. FindingsBetween March, 2018, and June, 2019, we included 218 women in the intervention group and 170 in the control group in the per protocol analyses after removing dropouts. There were no differences between intervention and control groups over time for primary outcomes in fully adjusted models. However, evidence of positive intervention effects was noted for some secondary outcomes: contacting an outreach worker (group by time 2 adjusted OR: 3·288 [95% CI 1·277–8·469]), receiving an escorted referral (group by time 2, 2·861 [1·089–7·518]; group by time 3, 8·150 [1·650–40·250]), and never being forced to drink at work (group by time 3, 3·945 [1·622–9·597]). InterpretationThe Mobile Link intervention effectively connected female entertainment workers in Cambodia with outreach workers and escorted referrals and reduced rates of forced drinking at work. Longer-term messaging has the potential to increase access to services and could improve health outcomes for female entertainment workers. Funding5% Initiative through Expertise France (Grant No. 16SANIN210).

Cell Partitioning Antenna System Performance in Multi-User Scenarios for mmWave Communications

Fixed-beam, high-gain antenna systems can be used for a finer partitioning of the currently used cell-sectoring. This partitioning has the benefit of reducing the number of users seen per antenna beam, which reduces interference. Furthermore, the high antenna gain allows for a high effective isotropic radiated power while keeping the transmit power low. In this paper, we study the performance of such a fixed-beam, high gain antenna system design for millimeter-wave mobile communications. The antenna system is designed to keep the inter-sector interference in a multi-site scenario low. The performance is analyzed for single- and multi-user environments. In single-input single-output mode, the 50th percentile of the signal-to-interference-plus-noise ratio lies between 12.5 dB to 39.7 dB if 3 to 0 interferers are present, respectively. For multiple-input multiple-output transmission using zero-forcing, the signal-to-interference-plus-noise ratio increases and the 50th percentile ranges from 36.1 dB to 43.3 dB if 3 to 0 interferes are present, respectively. By using maximum ratio transmission, the best performance is achieved with no interferers present, while a plunge in performance is observed with interferers. Furthermore, the study revealed that the narrow beam antenna system can also provide a clear signal separation for small spatial separations. In the given example, the signal-to-interference-plus-noise ratio is larger than 32.1 dB with 11 active antenna elements, where 2.8 meters separate the users. Hence, the paper shows that the cell-partitioning antenna systems provide coverage in the desired area while keeping the inter-sector interference low, and the considered transmission techniques can be used for situation optimized mobile communication links.

Design of Novel Mobility and Obstacle-Aware Algorithm for Optimal MANET Routing

Existence obstacles in terrain area and the mobility of the nodes in the network are the vital constrains that degrade the performance in Mobile Adhoc Network (MANET). To diminish the effect of such obstacles and mobility on the performance of MANET, the protocol used for routing must be efficient enough to handle both the factors. In the present work, we have considered the issues of Mobility and obstacle aware multipath communication in MANET. For avoiding obstacles, DeCasteljau Algorithm with Bezier curve concept has been applied. To the minimize impact of mobility, a speed based mobility prediction concept is used. Here optimal routing path across the obstacle is selected depending on its mobility prediction indicator, link duration, network connectivity and path availability. The performance of the suggested protocol is evaluated with Network Simulator-2. Simulation results confirm that the suggested protocol minimizes average energy consumption, network overhead, average delay and improves data deliverance in MANET.