Live Video Transmission Research Articles

Web Conferencing

Society, people, and institutions have reaped the benefits of technologies that allow online meetings and collaboration in real-time ¬¬¬¬- often known as web conferencing technologies. Most of the benefits of these technologies were observed during the COVID-19 pandemic, where efforts to prevent the spread of the virus introduced mass social distancing. In higher education, web conferencing benefits a growing number of students across the world. It enables synchronous online learning, where learning takes place in real time, with communication technologies that permit live audio, video, and text transmission. Extant research suggests that the interplay of technical and social challenges within synchronous online learning, before the COVID-19 pandemic and beyond, has not been comprehensively investigated. Additionally, there is a need for thorough studies on the effects of prolonged virtual interactions on individuals, teams, and organizations, stemming from the features of web conferencing technologies. This paper reports ongoing research aimed at exploring the technical and social challenges that affect the success of web conferencing in synchronous online learning. The research investigates the experiences of students and teachers who use these technologies for learning and teaching, and the challenges they face. The work uses theories of technology acceptance and the psychology of user behaviours. The research aims to advance knowledge and offer valuable information to educators and learners. It seeks to enhance the effectiveness of teaching and learning processes using web conferencing technologies, ensuring that they successfully achieve their intended outcomes. The results of this study, in the long-term, will also inform the development of better and improved interventions, practices and strategies for web conferencing, that can be applied in educational and even commercial contexts. The paper also discusses an exploratory study that was conducted to explore the effects of webcam usage on learner engagement in training and tutorial sessions among higher education students. The exploratory study showed that the webcam, even though rarely used in most sessions, had an impact on learner engagement, and can be explored further. Additionally, the technical and social aspects in these online sessions are complex and need more examination.

Feasibility of Live Video Feed Transmission from Unmanned Aerial Vehicles for Medical Surveillance During the 2022 Montreal Marathon.

In recent years, unmanned aerial vehicles (UAVs) have been increasingly used for medical surveillance purposes in mass-gathering events. No studies have investigated the reliability of live video transmission from UAVs for accurate identification of distressed race participants in need of medical attention. The aim of this study was to determine the proportion of time during which live medical surveillance UAV video feed was successfully transmitted and considered of sufficient quality to identify acute illness in runners participating in the 2022 Montreal Marathon (Canada). Four UAVs equipped with high-resolution cameras were deployed at two pre-defined high-risk areas for medical incidents located within the last 500 meters of the race. The video footage was transmitted in real-time during four consecutive hours to a remote viewing station where four research assistants monitored it on large screens. Interruptions in live feed transmission and moments with inadequate field of view (FOV) on runners were documented. On September 25, 2022, a total of 6,916 athletes ran during the Montreal Marathon and Half Marathon. Out of the eight hours of video footage analyzed (four hours per high-risk area), 91.7% represented uninterrupted live video feed with an adequate view of the runners passing through the high-risk areas. There was a total of 18 live feed interruptions leading to a total interruption time of 22 minutes and 19 seconds (median interruption time of 32 seconds) and eight distinct moments with inadequate FOV on runners which accounted for 17 minutes and 33 seconds (median of 1 minute 47 seconds per moments with inadequate FOV). Active surveillance of drone-captured footage allowed early identification of two race participants in need of medical attention. Appropriate resources were dispatched, and UAV repositioning allowed for real-time viewing of the medical response. Live video transmission from UAVs for medical surveillance of runners passing through higher risk segments of a marathon for four consecutive hours is feasible. Live feed interruptions and moments with inadequate FOV could be minimized through practice and additional equipment redundancy.

“You Are Essentially Just a Number”: Discourse Elaboration and Devaluation among Natural Science Students

This article analyzes first-year natural science students’ experiences of discourse and devaluation as new members of the Natural and Agricultural Sciences Faculty at the University of Pretoria (UP). This study aims to highlight students’ perspectives on navigating digital learning during COVID-19. Second, the analysis aims to highlight how intersections between languages, digital learning tools, and students’ identities intersect in an academic literacy module. Lastly, the investigation aims to formulate methodical propositions that academic literacy facilitators can apply to generate experiences of discourse elaboration as opposed to devaluation. This study was conducted at the Hatfield campus of the University of Pretoria, Gauteng province in South Africa among first-year natural science scholars. To unearth students’ experiences, this analysis employed a qualitative and phenomenological line of inquiry. Accordingly, the researchers interviewed 17 students in 2021 as part of a pilot project for a master’s degree project. All structured interviews were conducted via live video transmission using Zoom. The results of the study indicated that most of the participants missed face-to-face interactions with peers and academic staff. The majority of participants indicated that the sole utilization of eLearning induced discourse devaluation. Simultaneously, participants expressed discourse elaboration through interacting with digital literacies in the LST 110 module. Key variables that shaped students’ diverse experiences of discourse elaboration and devaluation are languages, identity, culture, and digital learning tools.

Feasibility of Live Video Feed Transmission from UAVs for Medical Surveillance During the 2022 Montreal Marathon

Introduction:In recent years, unmanned aerial vehicles (UAVs) have been increasingly used for medical surveillance purposes in mass gathering events. No studies have investigated the reliability of live video transmission from UAVs for accurate identification of distressed race participants in need of medical attention. During the 2022 Montreal marathon, the aim of this study was to determine the proportion of data collection time during which live medical surveillance UAV video feed was successfully transmitted and considered of sufficient quality to identify acute illness.Method:Four UAVs equipped with high resolution cameras were deployed at two predefined high-risk areas for medical incidents located within the last 800m of the race. The video footage was transmitted in real-time during four consecutive hours to a remote viewing station where four research assistants monitored it on large screens. Interruptions in live feed transmission and moments with inadequate field of view on runners were documented.Results:On September 25, 2022, 8,577 athletes registered in the Montreal marathon and half marathon. Out of the eight hours of video footage analyzed (four hours per high-risk area), 91.7% represented uninterrupted live video feed with an adequate view of the runners passing through the high-risk areas. The total interruption time was 22 minutes and 19 seconds, and the field of view was considered inadequate for a total of 17 minutes and 33 seconds. Active surveillance of drone-captured footage allowed identification of two race participants in need of medical attention. Appropriate resources were dispatched, and UAV repositioning allowed for real-time viewing of the medical response.Conclusion:Live video transmission from UAVs for medical surveillance of runners passing through higher-risk segments of a marathon race for four consecutive hours is feasible. Live feed interruptions and segments with an inadequate field of view could be minimized through practice and additional equipment redundancy.

A Super-Resolution Flexible Video Coding Solution for Improving Live Streaming Quality

In the context of the latest growing popularity of live video streaming, ensuring high video quality has become one of the most significant challenges faced by all live streaming platforms. Insufficient uplink bandwidth is an important factor that influences these live video transmissions, affecting their bitrate and latency and consequently the associated video streaming quality. This paper proposes a novel flexible super-resolution-based video coding and uploading framework (FlexSRVC) that improves the quality of live video streaming in limited uplink network bandwidth conditions. FlexSRVC includes a flexible video coding scheme, which compresses high-resolution key and non-key video frames to a lower bitrate in order to reduce the upload delay. A new flexible bitrate adaptation algorithm is also proposed to select dynamically the number of frames to be compressed and the compression ratio by jointly considering uplink network conditions and available cloud computing resources. Trace-driven emulations demonstrate that FlexSRVC provides the same quality while reducing up to 25% of the required bandwidth compared to the original encoding method (H.264). FlexSRVC improves users' QoE by at least 50% compared to a super resolution-based method which employs reconstruction of all video frames in uplink bandwidth constrained conditions.

Inferring End-to-End Latency in Live Videos

This paper provides an end-to-end latency model of real-time generated live videos composed of sub-models of capturing, encoding, network, decoding, rendering, and display refreshing. We build the model by deeply analyzing each sub part’s latency with parameters like video’s Spatial (frame scale <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$s$ </tex-math></inline-formula> ), Temporal (frame rate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$t$ </tex-math></inline-formula> ), Amplitude (quantization step-size <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$q$ </tex-math></inline-formula> ) Resolutions (STAR), Compressed Frame Bit Numbers ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n_{F}$ </tex-math></inline-formula> ), and other necessary parameters. The latency of 640 combinations of STAR for eight representative video sequences is measured to fit accurate models. We primarily focus on processing procedures, whose latency is becoming the principal affection, as network latency decreases due to the its development. We then introduce a baseline video sequence set to reduce the complexity when fitting the encoding and decoding sub-models by predicting the model parameters on new hardware from parameters of a known one, and improve models’ robustness crossing different scenarios. These sub-models correlate well with the realistic latency data, with the average Pearson Correlation Coefficient (PCC) of 0.99 and the average Spearman’s Rank Correlation Coefficient (SRCC) of 0.98, according to an independent validation test. Furthermore, we validate our end-to-end latency model in a simulated end-to-end live video transmission from generating to displaying, introducing the latency as a strict condition in adaptive bit-rate selection. The simulation shows that our model could significantly increase time during which the latency can satisfy the given tolerance at a low cost.

Streaming from a Diagnostic and Therapeutic Endoscopy Room: It Is Possible at Low Cost

<i>Background and Aims</i>: Before the covid-19 pandemic, medicine was practice and taught almost entirely face-to-face. The new normal, presented us with an opportunity to change the paradigm. Previously, live video transmission was only possible with the use of satellites, that were too expensive to be use regular bases. Now it is possible to broadcast live cases, from anywhere around de world, at a relative low cost. <i>Methodology</i>: This is a descriptive study to show the experience in transmissions of endoscopy live procedures from endoscopy rooms of different centers of Latin America ascribed to the Latin American Training Center (LAGE-TC) adapting virtual transmission technologies for a diagnostic and therapeutic endoscopy, to broadcast cases in real-time through the internet. <i>Results</i>: From April 2020 to July 31^th, 2020 we have made transmissions every week, for each center, being Tuesdays designated for transmissions from Manizales in Colombia from the Unión de Cirujanos SAS (Dr Lázaro Arango M), Wednesdays from San Borja Arriaran, in Santiago de Chile (fellows training center of Latin America and from where the LAGE-TC is born) (Drs. Claudio Sergio Navarrete Garcia- Cecilia Castillo T, Carlos Barrientos- Ignacio Robles and Arturo Valle) and from San Juan in Argentina (Dr Marcelo Ponce), on Thursdays from Santa Fé Argentina (Dr. Hugo Imcof), and the Clínica del Norte in Barranquilla - Colombia (Drs. Jesús Rodríguez and Álvaro Jalal). Transmissions have also been made from other centers in Santiago de Chile, Mendoza (Dr Jorge Isaguirre) and Cordoba (Dra Jackelina Gobelet) in Argentina, and in Bucaramanga - Colombia (Dr Eduardo Valdivieso – Fundación Ildetecsa). 23 live broadcasts of cases from all the named cities in Latin America have been made, almost all from one center and being seen by the other centers already named as initial tests. One of the last meetings was held simultaneously between the Latin American Training Center in Santiago de Chile and the Hospital de San Juan in Argentina. The transmissions were done with good quality of video and sound, at a relative low cost. <i>Conclusion</i>: The study shows in detail different ways in which an endoscopy room can be adapted to perform live broadcasts with elements easy to get and at low cost, with good quality images. The adaptation of this technology will allow live transmission of medical classes, conferences with large audience, consultation form experts on line in other units, cities or countries, to improve medical knowledge and care.

Development of a real-time framework for farm monitoring using drone technology

This work developed a cost-effective framework for agriculturists to regularly monitor their crops against intruding rodents and other security concerns using modern drone technology through configuration and deployment of an autonomous UAV which also functions as a remotely piloted vehicle. This was done by configuring a quadcopter capable of causing a disturbance when a rodent is observed through an inbuilt alarm system whose sound is amplified to be loud enough to cause the animals to leave the farm area. A framework for real-time image and live video transmission from the farm to a designated remote base station was developed. This was achieved through programming codes that configured the drone to operate an intelligent alarm and object tracking systems which enables a live feed from the UAV using Arduino IDE and Mission Planner for autonomous flight control. The requisite algorithms were developed using the framework of tracking, learning and detection (TLD) in the OpenCV software. The drone movement is equally controlled remotely over a Wi-Fi network using an ESP8266 Wi-Fi module for redirection and controlling of the drone movement to monitor specific locations.

The Study of Intention to Apply Live Video Transmission System in Disaster Sites for Firefighters through UTAUT model

With the rapid development of network technology, the live video transmission system (LVTS) has improved the work efficiency because of the visual communication combining both images and data. In order to strengthen the effectiveness of disaster prevention through instant communication, the Fire Department in Taiwan has used the “VVLINK” videoconferencing system to provide multi-functional online conferences, and even grasp on-site dynamic situation of disasters in the first time, and then giving order to the disaster relief site online. Here, a research about the application of LVTS system in disaster sites was carried out to study the intention for firefighters in Fire Bureau of Changhua County, Taiwan. In this study “behavioural intension (BI)” and “usage behaviour (UB)” on LVTS system are explored through the Integrated Technology Acceptance Model (UTAUT). In addition, moderate variables such as gender, age, experience and voluntary are needed to be considered. “Performance expectation (PE)”, “effort expectation (EE)” and “social influence (SI)” can affect BI to be very significant; BI and “facilitating conditions (FC)” can also affect UB. Questionnaire analysis was applied. The results show that PE, EE, and SI have a positive direct impact on BI, and BI also has a positive direct impact on UB. It was also found that the FC had a positive and direct impact on BI as well as SI impacting on UB. All the moderate variables have significant difference on each UTAUT categories.

Lung Transplantation: The Indian Experience and Suggested Guidelines Part II A: The Technique of Lung Transplantation

Background: A series of lectures and workshop on lung and heart–lung transplantation were organized by the Departments of Cardiology and Cardiothoracic Surgery at All India Institute of Medical Sciences, New Delhi, and the Department of Heart and Lung Transplantation at Apollo Hospitals, Chennai. The 1st day workshop on preoperative workup part was published as Part-I in this journal in August 2018. The hands-on cadaveric workshop conducted on May 20, 2018, forms the basis of the first section of the second part (Part II a) which deals with the technique of lung transplantation. The techniques of lung transplantation and Indian scenario are also reviewed. Methodology: The technique practiced by the transplant team at Apollo Hospitals, Chennai, was used for the demonstration of donor lung, heart–lung block harvest and implanting lungs, heart–lung block, while also discussing other possible techniques. Human cadavers were used, and live high-definition audio–video transmission to the lecture hall was made. Results: Accurate figures regarding lung transplantation in India are still not available. However, as per the Indian Society for Heart and Lung Transplantation, current data suggest that overall, about 1050 heart transplants and 310 lung transplants have been done in India. Of these, it is anticipated that national data regarding number of single-lung transplants, double-lung transplants, and heart–lung transplants will be available soon. The Department of Heart and Lung Transplantation at Apollo Hospitals, Chennai, has performed a total of 69 hearts and 149 lungs in 119 patients in various combinations: isolated heart transplants (40 patients), double-lung transplantation (DLT) (43 patients), single-lung transplantation (7 patients), heart and DLT (27 patients), en bloc heart and liver transplantation (1 patient), and combined heart–lung and kidney transplantation (1 patient). While the survival data for India are not currently available, our 3-year survival for DLT is 76.2%. Conclusions: While the surgical technique demonstrated is used in most of our cases, at times, different techniques have had to be adopted based on challenges confronted on the operating table. However, we have found that developing surgical protocols and maintaining consistency in the operative techniques translates into good surgical outcomes.

Media Transmission by Cooperation of Cellular Network and Broadcasting Network

Future media transmission as a consistent target is pursued by both next mobile communication system (5G) and advanced digital terrestrial television system. High data rate and flexibility are major considerations for future media transmission. Broadcasting network facilitates high-efficiency transmission of popular or live video in large area, and while, cellular network tends to provide personalized and localized services with a unicast/multicast model. The broadcast-like scheme emerges in 5G to resolve the high demand for bandwidth. However, it requires high deployment cost and imposes much interference on unicast/multicast services. In this paper, a cooperative structure of cellular network and broadcasting network using cloud radio access network (C-RAN) is proposed. The expenses of constructing hybrid network can be significantly cut down by applying the centralization and virtualization of C-RAN. Besides, technical approaches for 3GPP and ATSC cooperation in physical layer is detailed. Dedicated return channel (DRC) of broadcasting network is proposed to enable seamless interaction between broadcasters and few users in a remote area with high expense of cellular tower deployment. To loosen the real-time physical layer pipes period restriction of DRC system, three alternative periods are investigated to provide more flexibility to broadcasters.

Legal Mapping Analysis of State Telehealth Reimbursement Policies.

There exists rapid growth and inconsistency in the telehealth policy environment, which makes it difficult to quantitatively evaluate the impact of telehealth reimbursement and other policies without the availability of a legal mapping database. We describe the creation of a legal mapping database of state-level policies related to telehealth reimbursement of healthcare services. Trends and characteristics of these policies are presented. Information provided by the Center for Connected Health Policy was used to identify statewide laws and regulations regarding telehealth reimbursement. Other information was retrieved by using: (1) LexisNexis database, (2) Westlaw database, and (3) retrieval from legislative Web sites, historical documents, and contacting state officials. We examined policies for live video, store-and-forward, and remote patient monitoring (RPM). In the United States, there are 24 states with policies regarding reimbursement for live video transmission. Fourteen states have store-and-forward policies, and six states have RPM-related policies. Mississippi is the only state that requires reimbursement for all three types of telehealth transmission modes. Most states (47 states) have Medicaid policies regarding live video transmission, followed by 37 states for store-and-forward and 20 states for RPM. Only 13 states require that live video will be reimbursed "consistent with" or at the "same rate" as in-person services in their Medicaid program. There are no widely accepted telehealth reimbursement policies across states. They contain diverse restrictions and requirements that present complexities in policy evaluation and in determining policy effectiveness across states.

Optimized Upload Strategies for Live Scalable Video Transmission from Mobile Devices

Sharing live multimedia content is becoming increasingly popular among mobile users. In this article, we study the problem of optimizing video quality in such a scenario using scalable video coding (SVC) and chunked video content. We consider using only standard stateless HTTP servers that do not need to perform additional processing of the video content. Our key contribution is to provide close to optimal algorithms for scheduling video chunk upload for multiple clients having different viewing delays. Given such a set of clients, the problem is to decide which chunks to upload and in which order to upload them so that the quality-delay tradeoff can be optimally balanced. We show by means of simulations that the proposed algorithms can achieve notably better performance than naive solutions in practical cases. Especially the heuristic-based greedy algorithm is a good candidate for deployment on mobile devices because it is not computationally intensive but it still delivers in most cases on-par video quality compared to the more complex local optimization algorithm. We also show that using shorter video segments and being able to predict bandwidth and video chunk properties improve the delivered video quality in certain cases.

Definition and test of the electromagnetic immunity of UAS for first responders

Abstract. Recent technological developments considerably lowered the barrier for unmanned aerial systems (UAS) to be employed in a variety of usage scenarios, comprising live video transmission from otherwise inaccessible vantage points. As an example, in the French-German ANCHORS project several UAS guided by swarm intelligence provide aerial views and environmental data of a disaster site while deploying an ad-hoc communication network for first responders. Since being able to operate in harsh environmental conditions is a key feature, the immunity of the UAS against radio frequency (RF) exposure has been studied. Conventional Electromagnetic Compatibility (EMC) applied to commercial and industrial electronics is not sufficient since UAS are airborne and can as such move beyond the bounds within which RF exposure is usually limited by regulatory measures. Therefore, the EMC requirements have been complemented by a set of specific RF test frequencies and parameters where strong sources are expected to interfere in the example project test case of an inland port environment. While no essential malfunctions could be observed up to field strengths of 30 V m−1, a sophisticated, more exhaustive approach for testing against potential sources of interference in key scenarios of UAS usage should be derived from our present findings.

Subjective Quality Assessment for Impaired Videos with Varying Spatial and Temporal Information

The new era of digital communication has brought up many challenges that network operators need to overcome. The high demand of mobile data rates require improved networks, which is a challenge for the operators in terms of maintaining the quality of experience (QoE) for their consumers. In live video transmission, there is a sheer need for live surveillance of the videos in order to maintain the quality of the network. For this purpose objective algorithms are employed to monitor the quality of the videos that are transmitted over a network. In order to test these objective algorithms, subjective quality assessment of the streamed videos is required, as the human eye is the best source of perceptual assessment. In this paper we have conducted subjective evaluation of videos with varying spatial and temporal impairments. These videos were impaired with frame freezing distortions so that the impact of frame freezing on the quality of experience could be studied. We present subjective Mean Opinion Score (MOS) for these videos that can be used for fine tuning the objective algorithms for video quality assessment. Keywords—Frame freezing, mean opinion score, objective assessment, subjective evaluation.

Enabling smartphone-based HD video chats by cooperative transmissions in CRNs

Abstract Smartphones have been equipped with the cameras that can shoot HD videos, and the video chat apps such as Skype are becoming popular. We can, therefore, intuitively predict the trend that users are expecting to enjoy HD video chats via utilizing their smartphones. Most of the current Internet services, however, cannot support the live HD video transmissions because of their low uplink rate. In order to overcome this limit, we propose to offload the uplink transmissions to cooperative users via cognitive radio networks. Specifically, we first divide the video stream into several substreams according to the H.264/SVC standard and the cooperative users’ uplink rates. Then, the cooperative users are selected by employing our proposed optimal multiple stopping method. Finally, the substreams are assigned to the selected cooperative users by a 0-1 Knapsack-based allocation algorithm. The simulation results demonstrate that our proposed scheme can successfully support 720P HD video chats.

Cortisol increase in empathic stress is modulated by emotional closeness and observation modality.

Stress disorders are among the most commonly occurring of all mental disorders. In this context, the question arises whether the stress inevitably unfolding around us has the potential to "contaminate" and compromise us. In the current multi-center study, we investigate the existence of such empathic stress (defined as a full-blown physiological stress response that arises solely by observing a target undergo a stressful situation), and whether empathic stress permeates to the core of the stress system, the hypothalamic-pituitary-adrenal (HPA) axis. Additionally, we investigate whether empathic stress responses may be modulated by the familiarity between observer and target (partners vs. strangers), the modality of observation (real-life vs. virtual) and observer sex (female vs. male). Participants were tested in dyads, paired with a loved one or a stranger of the opposite sex. While the target of the dyad (n=151) was exposed to a psychosocial stressor, the observer (n=211) watched through a one-way mirror or via live video transmission. Overall, 26% of the observers displayed physiologically significant cortisol increases. This empathic stress was more pronounced in intimate observer-target dyads (40%) and during the real-life representation of the stressor (30%). Empathic stress was further modulated by interindividual differences in empathy measures. Despite the higher prevalence of empathic stress in the partner and real-life observation conditions, significant cortisol responses also emerged in strangers (10%) and the virtual observation modality (24%). The occurrence of empathic stress down to the level of HPA-axis activation, in some cases even in total strangers and when only virtually witnessing another's distress, may have important implications for the development of stress-related diseases.

Second Annual Workshop of the Mid-Atlantic Chapter of the American Society of Peritoneal Surface Malignancy

Second Annual Workshop of the Mid-Atlantic Chapter of the American Society of Peritoneal Surface Malignancy, Mercy Medical Center, Baltimore, MD, USA, 20–21 June 2013 The annual workshop is dedicated to the regional advancement and coordination of efforts to control the peritoneal surface component of gastrointestinal and gynecologic malignancy. It was attended by surgeons, medical oncologists, radiologists, gastroenterologists and nurses involved in clinical and laboratory research efforts to optimally manage peritoneal metastases and peritoneal mesothelioma. During the first day of the 2-day meeting, presentations were coordinated with live video transmission from the operating room at Mercy Medical Center (MD, USA). The live surgery, didactic speeches and patient presentations were displayed for open discussion in real-time. Twenty regional and global opinion leaders spoke and interacted regarding clinical and research information relevant to the rapidly developing multidisciplinary subspecialty of peritoneal surface oncology.

Improved Reception of In-Body Signals by Means of a Wearable Multi-Antenna System

High data-rate wireless communication for in-body human implants is mainly performed in the 402–405 MHz Medical Implant Communication System band and the 2.45 GHz Industrial, Scientific and Medical band. The latter band offers larger bandwidth, enabling high-resolution live video transmission. Although in-body signal attenuation is larger, at least 29 dB more power may be transmitted in this band and the antenna efficiency for compact antennas at 2.45 GHz is also up to 10 times higher. Moreover, at the receive side, one can exploit the large surface provided by a garment by deploying multiple compact highly efficient wearable antennas, capturing the signals transmitted by the implant directly at the body surface, yielding stronger signals and reducing interference. In this paper, we implement a reliable 3.5 Mbps wearable textile multi-antenna system suitable for integration into a jacket worn by a patient, and evaluate its potential to improve the In-to-Out Body wireless link reliability by means of spatial receive diversity in a standardized measurement setup. We derive the optimal distribution and the minimum number of on-body antennas required to ensure signal levels that are large enough for real-time wireless endoscopy-capsule applications, at varying positions and orientations of the implant in the human body.

Dynamic overlay multicast for live multimedia streaming in urban VANETs

Infotainment service has been a foreseeing trend in VANETs (Vehicular Ad Hoc Networks), and multimedia streaming has a high potential in VANET infotainment service. This paper considers the scenario of live multimedia streaming multicast to vehicles of the same group using a dynamic application layer overlay. Due to the willingness for cooperation of non-group nodes, application layer overlay multicast is more feasible than other kinds of multicast such as network-coding-based multicast and network-layer multicast. To adapt to high mobility and full of obstacles in urban VANETs, we propose an effective dynamic overlay multicast scheme for multimedia streaming, called OMV (Overlay Multicast in VANETs). The proposed OMV enhances an overlay’s stability with two strategies: (1) QoS-satisfied dynamic overlay and (2) mesh-structure overlay. The QoS-satisfied strategy to adjust the overlay selects potential new parents based on their streams’ packet loss rates and end-to-end delays. The mesh-structure strategy allows a child to have multiple parents. We evaluate the proposed OMV in urban VANETs with obstacles using two real video clips to demonstrate the feasibility of the OMV for real videos. Evaluation results show that comparing the proposed OMV to Qadri et al.’s work, which is a static mesh overlay and is the best method available in VANETs, the packet loss rate is reduced by 27.1% and the end-to-end delay is decreased by 11.7%, with a small control overhead of 2.1%, on average. Comparing the proposed OMV for tree overlays to ALMA, which is for dynamic tree multicast overlays and is also the best method available in MANETs, the packet loss rate is reduced by 7.1% and the end-to-end delay is decreased by 13.1%. In addition, to address the problem of obstacle-prone urban VANETs, we also derive feasible stream rates and overlay sizes for city maps with different road section sizes. To the best of our knowledge, how to organize and dynamically adjust an application layer multicast overlay for live multimedia streaming have not been studied in existing VANET literatures. In summary, to deal with highly dynamic topologies in urban VANETs, we propose a QoS-satisfied strategy for group nodes to switch to new parents that can offer better QoS. The proposed OMV is feasible for live multimedia streaming applications, such as emergency live video transmission and live video tour guides for passengers in different vehicles that belong to the same multicast group.