Performance analysis of a discrete-time queueing system with customer deadlines

This paper studies a discrete-time queueing system where each customer has a maximum allowed sojourn time in the system, referred to as the "deadline" of the customer. Deadlines of consecutive customers are modelled as independent and geometrically distributed random variables. The arrival process of new customers, furthermore, is assumed to be general and independent, while service times of the customers are deterministically equal to one slot each. For this queueing model, we are able to obtain exact formulas for quantities as the mean system content, the mean customer delay, and the deadline-expiration ratio. These formulas, however, contain infinite sums and infinite products, which implies that truncations are required to actually compute numerical values. Therefore, we also derive some easy-to-evaluate approximate results for the main performance measures. These approximate results are quite accurate, as we show in some numerical examples. Possible applications of this type of queueing model are numerous: the (variable) deadlines could model, for instance, the fact that customers may become impatient and leave the queue unserved if they have to wait too long in line, but they could also reflect the fact that the service of a customer is not useful anymore if it cannot be delivered soon enough, etc

Modelo de sincronização de vídeo para SAGE2 baseado em mídia adaptável.

Although SAGE2 is a stable collaborative workplace it has been a challenge synchronize dynamic applications among a screens in a video wall. The Fogo Player used in SAGE2 was developed at LAViD(Digital Laboratory of Video Applications) using web tools such as Javascript and HTML5 which had problems with media synchronization caused by browsers initialization with di erent times. Therefore this work proposal is to use techniques like adaptive media synchronization to compensate the browsers video playback start delay, in order to makes a better synchronization in video applications to show a better video synchronization on SAGE2 using video wall.O SAGE2 é uma área de trabalho colaborativa estável com o proposito de fazer aplicações dinâmicas parecerem síncronas nos displays em um painel de vídeo wall . A integração do Fogo Player no SAGE2 foi desenvolvida no laboratório de aplicações de vídeo digital (LAViD) usando linguagens de programação web como Javascript e HTML5, porem a mesma possui um problema de sincronização de mídia causada por uma diferença no tempo de inicialização dos navegadores que gerenciam cada um dos displays. A proposta desse trabalho é, através de técnicas de sincronização por mídia adaptiva e de uma aplicação dinâmica de vídeo, compensar o tempo de inicialização dos navegadores utilizados pelo SAGE2 permitindo uma melhor sincronia do vídeo e experiencia do usuário

Inter-destination Multimedia Synchronization: A Contemporary Survey

The advent of social networking applications, media streaming technologies, and synchronous communications has created an evolution towards dynamic shared media experiences. In this new model, geographically distributed groups of users can be immersed in a common virtual networked environment in which they can interact and collaborate in real- time within the context of simultaneous media content consumption. In this environment, intra-stream and inter-stream synchronization techniques are used inside the consumers’ playout devices, while synchronization of media streams across multiple separated locations is required. This synchronization is nown as multipoint, group or Inter-Destination Multimedia Synchronization (IDMS) and is needed in many applications such as social TV and synchronous e-learning. This survey paper discusses intraand inter-stream synchronization issues, but it mainly focuses on the most well-known IDMS techniques that can be used in emerging distributed multimedia applications. In addition, it provides some research directions for future work

PAMTEL-RT: Web-based Multimedia Platform for Tele-Assistance of Pediatric Health Emergencies in Real Time in Training Centers

[EN] In this paper, PAMTEL-RT, a web-based platform to provide remote health professional support and guidance during the initial assistance of emergency situations is presented. In particular, this platform focuses on the pediatric population and has been specifically designed to be used by non-healthcare professionals in training centers, such as educational or sport centers. It allows pediatricians in hospitals to use Information and Communication Technologies to assist or guide, in real-time, training personnel in charge of children when any emergency situation may arise. A direct and secure real-time connection between the medical and training centers is established, allowing sharing multiple media, such as audio, video, images, documents, text and data. Since the implementation relies on standard web-based technologies, cross-network, cross-platform and cross-device support are ensured. At first, an opinion and acceptance survey was conducted to collect requirements from some potential users to consider their opinions when designing and developing the platform. In line with the obtained results, the architecture of the platform has been designed, and a prototype has been developed and preliminarily evaluated through 12 drills/simulations in 7 education and sports centers. In the evaluation, 24 training personnel were involved, who considered that its usability was excellent and that it would have applicability in their centers. Furthermore, they considered that the included functionalities in the platform are appropriate and believed that the use of PAMTEL-RT could be highly effective in the early management of extreme emergency situations, and, in some cases, in avoiding tragic consequences.This work has been partially funded by the Universitat Politecnica de Valencia (UPV) and the Foundation for the Promotion of Health and Biomedical Research of Valencia Region (FISABIO), under their R&D&I Support Program with references UPV-FISABIO-2017-002-940. Authors also want to thank educational and sport institutions involved in the drills: Gregori Maians and Esclavas del Sagrado Corazón de Jesús Schools in Gandia city; Batoi and Pare Victoria Schools in Alcoi city; and U.E. Gandia Football Club, and C.A. Safor Delikia and C.C. El Garbí athletics clubs, in Gandia cityBoronat, F.; Escrivá, P.; Salvador-Llàcer, P.; Pareja, F.; Pastor, J. (2021). PAMTEL-RT: Web-based Multimedia Platform for Tele-Assistance of Pediatric Health Emergencies in Real Time in Training Centers. Multimedia Systems. 27(2):205-227. https://doi.org/10.1007/s00530-020-00730-0205227272Tomines, A.: Pediatric telehealth: approaches by specialty and implications for general pediatric care. Adv. Pediatr. 66, 55–85 (2019). https://doi.org/10.1016/j.yapd.2019.04.005European Commission. A healthy approach. Technology for personalized, preventative healthcare. ICT Research: the policy perspective. Publications Office of the European Union, 2010. 24 pp. ISBN 978-92-79-16085–1. (2010). https://doi.org/10.2759/33350EXPH (EXpert Panel on effective ways of investing in Health), Assessing the impact of digital transformation of health services, 20 November 2018. https://ec.europa.eu/health/expert_panel/sites/expertpanel/files/docsdir/022_digitaltransformation_en.pdf (2020). Accessed May 2020Olson, C.A., McSwain, S.D., Curfman, A.L., et al.: The current pediatric telehealth landscape. Pediatrics 141(3), e20172334 (2018)Burke, B.L., Jr., Hall, R.W.: Telemedicine: pediatric applications. Pediatrics 136(1), e293-308 (2015). https://doi.org/10.1542/peds.2015-1517McConnochie, K.M., Tan, J., Wood, N.E., et al.: Acute illness utilization patterns before and after telemedicine in childcare for inner-city children: a cohort study. Telemed. J. E Health 13(4), 381–390 (2007)McConnochie, K.M., Wood, N.E., Herendeen, N.E., et al.: Telemedicine in urban and suburban childcare and elementary schools lightens family burdens. Telemed. J. E Health 16(5), 533–542 (2010). https://doi.org/10.1089/tmj.2009.0138Utidjian, L., Abramson, E.: Pediatric telehealth: opportunities and challenges. Pediatr Clin. N. Am. 63(2), 367–378 (2016). https://doi.org/10.1016/j.pcl.2015.11.006Qubty, W., Patniyot, I., Gelfand, A.: Telemedicine in a pediatric headache clinic: a prospective survey. Neurology. 90(19), e1702–e1705 (2018). https://doi.org/10.1212/WNL.0000000000005482Stavas, N., Shea, J., Keddem, S., et al.: Perceptions of caregivers and adolescents of the use of telemedicine for the child sexual abuse examination. Child Abuse Negl. 85, 47–57 (2018)Vyas, S., Murren-Boezem, J., Solo-Josephson, P.: Analysis of a pediatric telemedicine program. Prog. Telemed. J. E Health (2018). https://doi.org/10.1089/tmj.2017.0281Bala, N., Price, S.N., Horan, C.M., et al.: Use of telehealth to enhance care in a family-centered childhood obesity intervention. Clin. Pediatr. 58(7), 789–797 (2019)mHealth Economics 2017. Current Status and Future Trends in Mobile Health: Research 2 Guidance. http://www.uzelf.org/wp-content/uploads/2017/12/R2G-mHealth-Developer-Economics-2017-Status-And-Trends.pdf (2020). Accessed May 2020Cisotto, G., Casarin, E., Tomasin, S.: Requirements and enablers of advanced healthcare services over future cellular systems. IEEE Commun. Mag. 58(3), 76–81 (2020). https://doi.org/10.1109/MCOM.001.1900349Morosi, S., Jayousi, S., Mucchi, L., et al.: Medical Tele-Monitoring and Tele-Assistance for Diabetics Patients by Means of 5G Cellular Networks, in Proceedings of BodyNets 2019. In: Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, vol 297. Springer, Cham (2019)Montagud, M., Boronat, F., Belda, J., et al.: Use of Web Components to Develop Interactive, Customizable and Multi-Device Video Consumption Platforms, Applications and Usability of Interactive TV, pp. 26–43. Springer, Berlin (2016)Arntzen, I., Bjorch, N., Daoust, F.: Media Synchronization on the Web. In: Montagud, M., Cesar, P., Boronat, F., Jansen, J. (eds.) MediaSync: Handbook on Multimedia Synchronization. Springer, Cham (2018)Pauwels, D., van der Hooft, J., Petrangeli, S., et al.: A Web-based framework for fast synchronization of live video players, IFIP/IEEE Symposium on Integrated Network and Service Management, Lisbon, 2017, pp. 524–530 (2017)Rainer, B., Petscharnig, S., Timmerer, C.: Merge and forward: a self-organized inter-destination media synchronization scheme for adaptive media streaming over HTTP. In: Montagud, M., Cesar, P., Boronat, F., Jansen, J. (eds.) MediaSync: Handbook on Multimedia Synchronization. Springer, Cham (2018)Montagud, M., Boronat, F., Stokking, H., et al.: Inter-destination multimedia synchronization: schemes, use cases and standardization. Multimedia Syst. J. 18(6), 459–482 (2012). https://doi.org/10.1007/s00530-012-0278-9Montagud, M., Boronat, F., Stokking, H., et al.: Design development and assessment of control schemes for IDMS in a standardized RTCP-based solution. COMNET 70(9), 240–259 (2014). https://doi.org/10.1016/j.comnet.2014.06.004Dynamic Adaptive Streaming Over HTTP (DASH): Part 1: media presentation description and segment formats, ISO/IEC Standard 23009-1: 2012 (2012)Gómez, D., Boronat, F., Montagud, M., et al.: End-to-end DASH platform including a network-based and client-based adaptive quality switching module. In: Proc. Int. Conf. Multimedia Syst., Klagenfurt, Austria, Art. no. 38 (2016)Melvin, H., Shannon, J., Stanton, K.: Time, frequency and phase synchronization for multimedia—basics, issues, developments and opportunities. In: Montagud, M., Cesar, P., Boronat, F., Jansen, J. (eds.) MediaSync: Handbook on Multimedia Synchronization. Springer, Cham (2018)Boronat, F., Lloret, J., García, M.: Multimedia group and inter-stream synchronization techniques: a comparative study. Inf. Syst. 34(1), 108–131 (2009). https://doi.org/10.1016/j.is.2008.05.001Montagud, M., Boronat, F., Pastor, J., et al.: Web-based platform for a customizable and synchronized presentation of subtitles in single- and multi-screen scenarios. Multimed Tools Appl (2020). https://doi.org/10.1007/s11042-020-08955-xSu, Y., Yang, Y., Lu, M., et al.: Smooth control of adaptive media playout for video streaming. IEEE TMM 1(7), 1331–1339 (2009)Rainer, B., Timmerer, C.: Self-Organized inter-destination multimedia synchronization for adaptive media streaming. In: Proceedings of the 22nd ACM international conference on Multimedia (MM '14). ACM, New York, NY, USA, pp. 327–336 (2014)Montagud, M., Boronat, F., Roig, B., et al.: How to perform AMP? Cubic adjustments for improving the QoE. Comput. Commun. 103, 61–73 (2017). https://doi.org/10.1016/j.comcom.2017.01.017Hossfeld, T., Seufert, M., Hirth, M., et al.: Quantification of YouTube QoE via crowdsourcing. IEEE ISM (2011). https://doi.org/10.1109/ISM.2011.87Park, S., Kim, J.: An adaptive media playout for intra-media synchronization of networked-video applications. J. Vis. Commun. Image Represent. 19(2), 106–120 (2008)Brooke, J.: Sus-a quick and dirty usability scale. In the book “Usability evaluation in industry”, issue 194, pages 189–194, Taylor and Francis Ed (1996)Bangor, A., Kortum, P., Miller, J.: Determining what individual sus scores mean: adding an adjective rating scale. J. Usability Stud. 4(3), 114–123 (2009

Plataforma web multimedia para docencia interactiva y colaborativa a distancia

[ES] Actualmente, hay nuevas formas de enseñanza a distancia, donde los estudiantes disponen de contenido multimedia. En este trabajo se ha desarrollado una plataforma basada en web, destinada a la docencia a distancia. Por un lado, en la misma se permite que un docente interactúe con un grupo de alumnos remotos de forma simultánea mientras visualizan, en grupo, contenido audiovisual o AV basado en tecnología DASH (por ejemplo, un vídeo polimedia) sobre el que el docente puede explicar conceptos teóricos. Por otro lado, los alumnos también pueden visualizar en grupo los contenidos docentes disponibles en la misma para poder preparar dichas materias de forma interactiva y colaborativa. Como medios de interacción, la plataforma incluye herramientas de mensajería de texto, de comunicaciones de audio y vídeo en tiempo real, control compartido de la reproducción del contenido AV, pizarra compartida y de intercambio de ficheros. Para el desarrollo de la plataforma se han utilizado tecnologías estándar basadas en web, por lo que se garantiza la compatibilidad entre redes, entre plataformas y entre dispositivos. Además, incluye soluciones de sincronización inter-flujo (contenidos AV y mensajes de texto) y de sincronización de la reproducción de los contenidos AV entre destinatarios (IDMS, Inter-Destination Media Synchronisation). El correcto funcionamiento de la plataforma y la precisión de la sincronización obtenida se han evaluado de forma objetiva (QoS) y subjetiva (QoE).[EN] Currently, there are new forms of distance learning, where students can count on multimedia content. In this work, a web-based platform has been developed, destined to distance learning. On the one hand, it allows a teacher to interact with a group of remote students simultaneously while visualizing in group DASH-based audiovisual content (AV) (for example, a video polimedia) on which the teacher can explain concepts teachers. On the other hand, students can also visualize in group the AV contents to be able to prepare these subjects in an interactive and collaborative way. As means of interaction, the platform includes text messaging tools, real-time audio and video communications, shared control of AV content playout, shared board and file sharing. Standard web-based technologies have been used for the development of the platform. So, compatibility between networks, between platforms and between devices is guaranteed. It also includes inter-stream synchronization solutions (AV content and text messages) and synchronization of the playout of the AV content between recipients (IDMS, Inter-destination Media Synchronization). The correct performance of the platform and the accurency of the obtained synchronization have been evaluated objectively (QoS) and subjectively (QoE).Salvador Llàcer, P. (2019). Plataforma web multimedia para docencia interactiva y colaborativa a distancia. Universitat Politècnica de València. http://hdl.handle.net/10251/145690TFG

Enhanced adaptive RTCP-based inter-destination multimedia synchronization approach for distributed applications

[EN] Newer social multimedia applications, such as Social TV or networked multi-player games, enable independent groups (or clusters) of users to interact among themselves and share services within the context of simultaneous media content consumption. In such scenarios, concurrently synchronized playout points must be ensured so as not to degrade the user experience on such interaction. We refer to this process as Inter-Destination Multimedia Synchronization (IDMS). This paper presents the design, implementation and evaluation of an evolved version of an RTCP-based IDMS approach, including an Adaptive Media Playout (AMP) scheme that aims to dynamically and smoothly adjust the playout timing of each one of the geographically distributed consumers in a specific cluster if an allowable asynchrony threshold between their playout states is exceeded. For that purpose, we previously had also to develop a full implementation of RTP/RTCP protocols for NS-2, in which we included the IDMS approach as an optional functionality. Simulation results prove the feasibility of such IDMS and AMP proposals, by adopting several dynamic master reference selection policies, to maintain an overall synchronization status (within allowable limits) in each cluster of participants, while minimizing the occurrence of long-term playout discontinuities (such as skips/pauses) which are subjectively more annoying and less tolerable to users than small variations in the media playout rate.This work has been financed, partially, by Universitat Politecnica de Valencia (UPV), under its R&D Support Program in PAID-05-11-002-331 Project and in PAID-01-10. Authors also would like to thank the anonymous reviewers that helped to significantly improve the quality of the paper with their constructive comments.Montagud, M.; Boronat, F. (2012). Enhanced adaptive RTCP-based inter-destination multimedia synchronization approach for distributed applications. Computer Networks. 56(12):2912-2933. https://doi.org/10.1016/j.comnet.2012.05.00329122933561