224 research outputs found
Multi-User Interactive TV: the Next Step in Personalization
In the past few years there has been an increasing trend towards personalization in the TV world. IMS-based IPTV is a good example of a highly personalized IPTV architecture, featuring an advanced identity management subsystem. This article studies a next step in the personalization of the television experience: concurrent use of TV services that are supported by the IMSbased IPTV system. That is, multiple users using the same television set at the same or at different times, where each user as personalized interaction with the service and content. Our analysis of IMS-based IPTV use cases shows that current architectures were not designed with concurrent use in mind. However, we demonstrate that the combination of concurrent use and personalized TV services can yield interesting and viable use cases in the areas of interactive game shows, personalized electronic program guides and channel lists, and other. Finally, an analysis of the IMS-based IPTV system and architecture shows that it has all the ingredients to implement these new concurrent TV use cases, and that the main challenges will be in the area of usability. The article concludes that personalization and concurrency are not contradictory for television services, neither from a use case perspective, nor technologically. In particular, the IMS-based IPTV system is able to facilitate an enhanced and personalized experience to concurrent TV users
Game Development Framework Based Upon Sensors and Actuators
Urge for comfort and excitement have made gadgets indispensable part of our life. The technology-enabled gadgets not only facilitate and enrich our daily lives but also are interesting tools to challenge human imagination to design and implement new ubiquitous applications. Pervasive gaming, in which human interaction and game/scenario-dependent designs are often common practices, has proved to be one of the areas to successfully combine technology and the human fantasy. By moving away from games being played by humans and by focusing instead on games played by robots and giving humans the leading role of defining game strategies and players’ roles, this paper aims at bridging the two fields of robotics and wireless sensor/actuator networks and exploring their potentials in the field of pervasive gaming. A generic game development framework is introduced that accommodates different types of robots and various kinds of sensors and actuators. Being extensible and modular, the proposed framework can be used for a wide range of pervasive applications built upon sensors and actuators. To enable game development, a Wiimote-based robot identification and localization technique is presented. The proposed framework and robot identification, localization, control and communication mechanisms are evaluated by implementing a game example
Inter-Destination Multimedia Synchronization; Schemes, Use Cases and Standardization
Traditionally, the media consumption model
has been a passive and isolated activity. However, the
advent of media streaming technologies, interactive social
applications, and synchronous communications, as well as
the convergence between these three developments, point
to an evolution towards dynamic shared media experiences.
In this new model, geographically distributed groups of
consumers, independently of their location and the nature
of their end-devices, can be immersed in a common virtual
networked environment in which they can share multimedia
services, interact and collaborate in real-time within
the context of simultaneous media content consumption. In
most of these multimedia services and applications, apart
from the well-known intra and inter-stream synchronization
techniques that are important inside the consumers
playout devices, also the synchronization of the playout
processes between several distributed receivers, known as
multipoint, group or Inter-destination multimedia synchronization
(IDMS), becomes essential. Due to the
increasing popularity of social networking, this type of
multimedia synchronization has gained in popularity in
recent years. Although Social TV is perhaps the most
prominent use case in which IDMS is useful, in this paper
we present up to 19 use cases for IDMS, each one having
its own synchronization requirements. Different approaches
used in the (recent) past by researchers to achieve
IDMS are described and compared. As further proof of the
significance of IDMS nowadays, relevant organizations
(such as ETSI TISPAN and IETF AVTCORE Group)
efforts on IDMS standardization (in which authors have
been and are participating actively), defining architectures
and protocols, are summarized.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, and by TNO, under its Future Internet Use Research & Innovation Program. The authors also want to thank Kevin Gross for providing some of the use cases included in Sect. 1.2.Montagud, M.; Boronat Segui, F.; Stokking, H.; Van Brandenburg, R. (2012). Inter-Destination Multimedia Synchronization; Schemes, Use Cases and Standardization. Multimedia Systems. 18(6):459-482. https://doi.org/10.1007/s00530-012-0278-9S459482186Kernchen, R., Meissner, S., Moessner, K., Cesar, P., Vaishnavi, I., Boussard, M., Hesselman, C.: Intelligent multimedia presentation in ubiquitous multidevice scenarios. IEEE Multimedia 17(2), 52–63 (2010)Vaishnavi, I., Cesar, P., Bulterman, D., Friedrich, O., Gunkel, S., Geerts, D.: From IPTV to synchronous shared experiences challenges in design: distributed media synchronization. Signal Process Image Commun 26(7), 370–377 (2011)Geerts, D., Vaishnavi, I., Mekuria, R., Van Deventer, O., Cesar, P.: Are we in sync?: synchronization requirements for watching on-line video together, CHI ‘11, New York, USA (2011)Boronat, F., Lloret, J., García, M.: Multimedia group and inter-stream synchronization techniques: a comparative study. Inf. Syst. 34(1), 108–131 (2009)Chen, M.: A low-latency lip-synchronized videoconferencing system. In: SIGCHI Conference on Human Factors in Computing Systems, CHI’03, ACM, pp. 464–471, New York (2003)Ishibashi, Y., Tasaka, S., Ogawa, H.: Media synchronization quality of reactive control schemes. IEICE Trans. Commun. E86-B(10), 3103–3113 (2003)Ademoye, O.A., Ghinea, G.: Synchronization of olfaction-enhanced multimedia. IEEE Trans. Multimedia 11(3), 561–565 (2009)Cesar, P., Bulterman, D.C.A., Jansen, J., Geerts, D., Knoche, H., Seager, W.: Fragment, tag, enrich, and send: enhancing social sharing of video. ACM Trans. Multimedia Comput. Commun. Appl. 5(3), Article 19, 27 pages (2009)Van Deventer, M.O., Stokking, H., Niamut, O.A., Walraven, F.A., Klos, V.B.: Advanced Interactive Television Service Require Synchronization, IWSSIP 2008. Bratislava, June (2008)Premchaiswadi, W., Tungkasthan, A., Jongsawat, N.: Enhancing learning systems by using virtual interactive classrooms and web-based collaborative work. In: Proceedings of the IEEE Education Engineering Conference (EDUCON 2010), pp. 1531–1537. Madrid, Spain (2010)Diot, C., Gautier, L.: A distributed architecture for multiplayer interactive applications on the internet. IEEE Netw 13(4), 6–15 (1999)Mauve, M., Vogel, J., Hilt, V., Effelsberg, W.: Local-lag and timewarp: providing consistency for replicated continuous applications. IEEE Trans. Multimedia 6(1), 45–57 (2004)Hosoya, K., Ishibashi, Y., Sugawara, S., Psannis, K.E.: Group synchronization control considering difference of conversation roles. In: IEEE 13th International Symposium on Consumer Electronics, ISCE ‘09, pp. 948–952 (2009)Roccetti, M., Ferretti, S., Palazzi, C.: The brave new world of multiplayer online games: synchronization issues with smart solution. In: 11th IEEE Symposium on Object Oriented Real-Time Distributed Computing (ISORC), pp. 587–592 (2008)Ott, D.E., Mayer-Patel, K.: An open architecture for transport-level protocol coordination in distributed multimedia applications. ACM Trans. Multimedia Comput. Commun. Appl. 3(3), 17 (2007)Boronat, F., Montagud, M., Guerri, J.C.: Multimedia group synchronization approach for one-way cluster-to-cluster applications. In: IEEE 34th Conference on Local Computer Networks, LCN 2009, pp. 177–184, Zürich (2009)Boronat, F., Montagud, M., Vidal, V.: Smooth control of adaptive media playout to acquire IDMS in cluster-based applications. In: IEEE LCN 2011, pp. 617–625, Bonn (2011)Huang, Z., Wu, W., Nahrstedt, K., Rivas, R., Arefin, A.: SyncCast: synchronized dissemination in multi-site interactive 3D tele-immersion. In: Proceedings of MMSys, USA (2011)Kim, S.-J., Kuester, F., Kim, K.: A global timestamp-based approach for enhanced data consistency and fairness in collaborative virtual environments. ACM/Springer Multimedia Syst. J. 10(3), 220–229 (2005)Schooler, E.: Distributed music: a foray into networked performance. In: International Network Music Festival, Santa Monica, CA (1993)Miyashita, Y., Ishibashi, Y., Fukushima, N., Sugawara, S., Psannis K.E.: QoE assessment of group synchronization in networked chorus with voice and video. In: Proceedings of IEEE TENCON’11, pp. 393–397 (2011)Hesselman, C., Abbadessa, D., Van Der Beek, W., et al.: Sharing enriched multimedia experiences across heterogeneous network infrastructures. IEEE Commun. Mag. 48(6), 54–65 (2010)Montpetit, M., Klym, N., Mirlacher, T.: The future of IPTV—Connected, mobile, personal and social. Multimedia Tools Appl J 53(3), 519–532 (2011)Cesar, P., Bulterman, D.C.A., Jansen, J.: Leveraging the user impact: an architecture for secondary screens usage in an interactive television environment. ACM/Springer Multimedia Syst. 15(3), 127–142 (2009)Lukosch, S.: Transparent latecomer support for synchronous groupware. In: Proceedings of 9th International Workshop on Groupware (CRIWG), Grenoble, France, pp. 26–41 (2003)Steinmetz, R.: Human perception of jitter and media synchronization. IEEE J. Sel. Areas Commun. 14(1), 61–72 (1996)Stokking, H., Van Deventer, M.O., Niamut, O.A., Walraven, F.A., Mekuria, R.N.: IPTV inter-destination synchronization: a network-based approach, ICIN’2010, Berlin (2010)Mekuria, R.N.: Inter-destination media synchronization for TV broadcasts, Master Thesis, Faculty of Electrical Engineering, Mathematics and Computer Science, Department of Network architecture and Services, Delft University of Technology (2011)Pitt Ian, CS2511: Usability engineering lecture notes, localisation of sound sources. http://web.archive.org/web/20100410235208/http:/www.cs.ucc.ie/~ianp/CS2511/HAP.htmlNielsen, J.: Response times: the three important limits. http://www.useit.com/papers/responsetime.html (1994)ITU-T Rec G. 1010: End-User Multimedia QoS Categories. International Telecommunication Union, Geneva (2001)Biersack, E., Geyer, W.: Synchronized delivery and playout of distributed stored multimedia streams. ACM/Springer Multimedia Syst 7(1), 70–90 (1999)Xie, Y., Liu, C., Lee, M.J., Saadawi, T.N.: Adaptive multimedia synchronization in a teleconference system. ACM/Springer Multimedia Syst. 7(4), 326–337 (1999)Laoutaris, N., Stavrakakis, I.: Intrastream synchronization for continuous media streams: a survey of playout schedulers. IEEE Netw. Mag. 16(3), 30–40 (2002)Ishibashi, Y., Tsuji, A., Tasaka, S.: A group synchronization mechanism for stored media in multicast communications. In: Proceedings of the INFOCOM ‘97, Washington (1997)Ishibashi, Y., Tasaka, S.: A group synchronization mechanism for live media in multicast communications. IEEE GLOBECOM’97, pp. 746–752 (1997)Boronat, F., Guerri, J.C., Lloret, J.: An RTP/RTCP based approach for multimedia group and inter-stream synchronization. Multimedia Tools Appl. J. 40(2), 285–319 (2008)Ishibashi, I., Tasaka, S.: A distributed control scheme for group synchronization in multicast communications. In: Proceedings of International Symposium Communications, Kaohsiung, Taiwan, pp. 317–323 (1999)Lu, Y., Fallica, B., Kuipers, F.A., Kooij, R.E., Van Mieghem, P.: Assessing the quality of experience of SopCast. Int. J. Internet Protoc. Technol 4(1), 11–19 (2009)Shamma, D.A., Bastea-Forte, M., Joubert, N., Liu, Y.: Enhancing online personal connections through synchronized sharing of online video, ACM CHI’08 Extended Abstracts, Florence (2008)Ishibashi, Y., Tasaka, S.: A distributed control scheme for causality and media synchronization in networked multimedia games. In: Proceedings of 11th International Conference on Computer Communications and Networks, pp. 144–149, Miami, USA (2002)Ishibashi, Y., Tomaru, K., Tasaka, S., Inazumi, K.: Group synchronization in networked virtual environments. In: Proceedings of the 38th IEEE International Conference on Communications, pp. 885–890, Alaska, USA (2003)Tasaka, S., Ishibashi, Y., Hayashi, M.: Inter–destination synchronization quality in an integrated wired and wireless network with handover. IEEE GLOBECOM 2, 1560–1565 (2002)Kurokawa, Y., Ishibashi, Y., Asano, T.: Group synchronization control in a remote haptic drawing system. In: Proceedings of IEEE International Conference on Multimedia and Expo, pp. 572–575, Beijing, China (2007)Hashimoto, T., Ishibashi, Y.: Group Synchronization Control over Haptic Media in a Networked Real-Time Game with Collaborative Work, Netgames’06, Singapore (2006)Nunome, T., Tasaka, S.: Inter-destination synchronization quality in a multicast mobile ad hoc network. In: Proceedings of IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications, pp. 1366–1370, Berlin, Germany (2005)Brandenburg, R., van Stokking, H., Van Deventer, M.O., Boronat, F., Montagud, M., Gross, K.: RTCP for inter-destination media synchronization, draft-brandenburg-avtcore-rtcp-for-idms-03.txt. In: IETF Audio/Video Transport Core Maintenance Working Group, Internet Draft, March 9 (2012)ETSI TS 181 016 V3.3.1 (2009-07) Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Service Layer Requirements to integrate NGN Services and IPTVETSI TS 182 027 V3.5.1 (2011-03) Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IPTV Architecture; IPTV functions supported by the IMS subsystemETSI TS 183 063 V3.5.2 (2011-03) Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specificationBrandenburg van, R., et al.: RTCP XR Block Type for inter-destination media synchronization, draft-brandenburg-avt-rtcp-for-idms-00.txt. In: IETF Audio/Video Transport Working Group, Internet Draft, Sept 24, 2010Williams, A., et al.: RTP Clock Source Signalling, draft-williams-avtcore-clksrc-00. In: IETF Audio/Video Transport Working Group, Internet Draft, February 28, 201
Accretion, Outflows, and Winds of Magnetized Stars
Many types of stars have strong magnetic fields that can dynamically
influence the flow of circumstellar matter. In stars with accretion disks, the
stellar magnetic field can truncate the inner disk and determine the paths that
matter can take to flow onto the star. These paths are different in stars with
different magnetospheres and periods of rotation. External field lines of the
magnetosphere may inflate and produce favorable conditions for outflows from
the disk-magnetosphere boundary. Outflows can be particularly strong in the
propeller regime, wherein a star rotates more rapidly than the inner disk.
Outflows may also form at the disk-magnetosphere boundary of slowly rotating
stars, if the magnetosphere is compressed by the accreting matter. In isolated,
strongly magnetized stars, the magnetic field can influence formation and/or
propagation of stellar wind outflows. Winds from low-mass, solar-type stars may
be either thermally or magnetically driven, while winds from massive, luminous
O and B type stars are radiatively driven. In all of these cases, the magnetic
field influences matter flow from the stars and determines many observational
properties. In this chapter we review recent studies of accretion, outflows,
and winds of magnetized stars with a focus on three main topics: (1) accretion
onto magnetized stars; (2) outflows from the disk-magnetosphere boundary; and
(3) winds from isolated massive magnetized stars. We show results obtained from
global magnetohydrodynamic simulations and, in a number of cases compare global
simulations with observations.Comment: 60 pages, 44 figure
Elliptic flow of electrons from heavy-flavor hadron decays in Au+Au collisions at 200, 62.4, and 39 GeV
We present measurements of elliptic flow () of electrons from the decays
of heavy-flavor hadrons () by the STAR experiment. For Au+Au collisions
at 200 GeV we report , for transverse momentum
() between 0.2 and 7 GeV/c using three methods: the event plane method
({EP}), two-particle correlations ({2}), and four-particle
correlations ({4}). For Au+Au collisions at = 62.4 and
39 GeV we report {2} for GeV/c. {2} and {4} are
non-zero at low and intermediate at 200 GeV, and {2} is consistent
with zero at low at other energies. The {2} at the two lower beam
energies is systematically lower than at 200 GeV for
GeV/c. This difference may suggest that charm quarks interact less
strongly with the surrounding nuclear matter at those two lower energies
compared to GeV.Comment: Version accepted by PR
Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at sqrt(s)= 7.7--62.4 GeV
Elliptic flow (v_2) values for identified particles at midrapidity in Au + Au
collisions measured by the STAR experiment in the Beam Energy Scan at the
Relativistic Heavy Ion Collider at sqrt{s_{NN}}= 7.7--62.4 GeV are presented
for three centrality classes. The centrality dependence and the data at
sqrt{s_{NN}}= 14.5 GeV are new. Except at the lowest beam energies we observe a
similar relative v_2 baryon-meson splitting for all centrality classes which is
in agreement within 15% with the number-of-constituent quark scaling. The
larger v_2 for most particles relative to antiparticles, already observed for
minimum bias collisions, shows a clear centrality dependence, with the largest
difference for the most central collisions. Also, the results are compared with
A Multiphase Transport Model and fit with a Blast Wave model.Comment: 14 pages, 12 figures, Phys. Rev. C, to be published. Data tables
available at
https://drupal.star.bnl.gov/STAR/publications/centrality-dependence-identified-particle-elliptic-flow-relativistic-heavy-ion-collisi
Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC
We present results from a harmonic decomposition of two-particle azimuthal
correlations measured with the STAR detector in Au+Au collisions for energies
ranging from GeV to 200 GeV. The third harmonic
, where is the
angular difference in azimuth, is studied as a function of the pseudorapidity
difference between particle pairs . Non-zero
{\vthree} is directly related to the previously observed large-
narrow- ridge correlations and has been shown in models to be
sensitive to the existence of a low viscosity Quark Gluon Plasma (QGP) phase.
For sufficiently central collisions, persist down to an energy of
7.7 GeV suggesting that QGP may be created even in these low energy collisions.
In peripheral collisions at these low energies however, is
consistent with zero. When scaled by pseudorapidity density of charged particle
multiplicity per participating nucleon pair, for central
collisions shows a minimum near {\snn} GeV.Comment: 7 pages, 4 figures, for submission to Phys. Rev. Let
- …