On game theoretic peer selection for resilient peer-to-peer media streaming

Peer-to-peer (P2P) media streaming quickly emerges as an important application over the Internet. A plethora of approaches have been suggested and implemented to support P2P media streaming. In our study, we first classified existing approaches and studied their characteristics by looking at three important quantities: number of upstream peers (parents), number of downstream peers (children), and average number of links per peer. In existing approaches, peers are assigned with a fixed number of parents without regard to their contributions, measured by the amount of outgoing bandwidths. Obviously, this is an undesirable arrangement as it leads to highly inefficient use of the P2P links. This observation motivates us to model the peer selection process as a cooperative game among peers. This results in a novel peer selection protocol such that the number of upstream peers of a peer is related to its outgoing bandwidth. Specifically, peers with larger outgoing bandwidth are given more parents, which make them less vulnerable to peer dynamics. Simulation results show that the proposed protocol improves delivery ratio using similar number of links per peer, comparing with existing approaches under a wide range of system parameters. © 2009 IEEE.published_or_final_versio

A game theoretic approach to energy efficient cooperative cache maintenance in MANETs

There have been an increasingly large number of mobile handsets equipped with dual or multiple network interfaces. The server interface (e.g., GPRS, EDGE, UMTS) is responsible for communicating with the network operator, while the peer interfaces (e.g., Bluetooth, IEEE 802.11) are used to connect with other computing devices. However, they are usually used separately. In this paper, we investigate the use of both network interfaces to support energy efficient data applications among mobile clients. Specifically, we proposed a fully distributed protocol for mobile handsets to form cooperative groups to maintain cache consistency with minimal communication with the network operator. Our proposed protocol takes advantage of the low power consumption and high data rate of the peer interface. The aim is to reduce the use of the server interface, which is typically slower and involves higher power consumption. Furthermore, we also consider the presence of selfish clients. It is shown that groups formed by the proposed protocol constitutes a pure Nash Equilibrium. This suggests that our protocol is robust even in the presence of selfish clients. Simulation results confirm that, given the same energy resource, mobile clients running the proposed protocol complete more queries, experience longer lifetime and achieve smaller query latency. © 2005 IEEE.published_or_final_versio

Wireless cache invalidation schemes with link adaptation and downlink traffic

Providing on-demand data access in client-server wireless networks is an important support to many interesting mobile computing applications. Caching frequently accessed data by mobile clients can conserve wireless bandwidth and battery power, at the expense of some system resources to maintain cache consistency. The basic cache consistency strategy is the use of periodic invalidation reports (IRs) broadcast by the server. Recently, IR-based approaches have been further improved by using additional updated invalidation reports (UIRs) (i.e., the IR+UIR algorithm) to reduce the long query latency. However, the performance of the IR+UIR approach in a practical system is still largely unknown. Specifically, previous results are based on two impractical simplifying assumptions: 1 ) broadcast traffic is error-free and 2) no other downlink traffic (e.g., voice) exists in the system. The first assumption is clearly unrealistic as signal propagation impairments (e.g., multipath fading) and, hence, packet reception failures are inevitable in a practical situation. The second assumption is also inapplicable in real life because mobile devices are usually multipurposed (e.g., a mobile phone equipped with a browser may be used for Web surfing while having a phone conversation). In this paper, we first study the performance of the IR+UIR approach under a realistic system model: The quality of the wireless channel is time-varying, and there are other downlink traffics in the system. Our simulation results show that query delay significantly increases as a result of broadcast error and the additional downlink traffics experience longer delay due to extended broadcast period. Exploiting link adaptation (i.e., transmission rate is adjusted dynamically according to channel quality), we then propose three schemes to tackle these two problems. Our results indicate that the proposed schemes outperform IR+UIR under a wide range of system parameters.published_or_final_versio

Design and analysis of channel adaptive wireless cache invalidation strategies with downlink traffic

In this paper, we study the performance of the IR+UIR wireless data cache Invalidation approach under a realistic system model: the quality of the wireless channel Is time-varying; and there are other downlink traffics in the system. Our analysis and simulation results show that query delay significantly increases as a result of broadcast error and the additional downlink traffics experience longer delay due to extended broadcast period. Exploiting link adaptation (i.e., transmission rate is adjusted dynamically according to channel quality), we then propose three schemes to tackle these two problems. Our results Indicate that the proposed schemes outperform IR+UIR under a wide range of system parameters.published_or_final_versio

The use of an HEPA respirator in combating SARS

published_or_final_versio

Assisted reproduction in Hong Kong: Status in the 1990s

Information on assisted reproduction in Hong Kong for the period from January 1992 to December 1993 was collected from the three centres that offer assisted reproduction. Altogether, 912 treatment cycles of in vitro fertilisation and embryo transfer, 158 treatment cycles of gamete intrafallopian transfer, and 87 cycles of zygote intrafallopian transfer were initiated during this period. The delivery rates per cycle started were 8.4% for in vitro fertilisation, 29.1% for gamete intrafallopian transfer, and 13.8% for zygote intrafallopian transfer. During the same period, 233 cycles of replacement of frozen thawed embryos were completed with a delivery rate of 11.2% per cycle. Pregnancies were also achieved using oocyte donation and micromanipulation techniques.published_or_final_versio

A spontaneous ad hoc network to share www access

In this paper, we propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system, the security algorithms implemented, and the designed messages. We have taken into account the security and its performance. Although some people have defined and described the main features of spontaneous ad-hoc networks, nobody has published any design and simulation until today. Spontaneous networking will enable a more natural form of wireless computing when people physically meet in the real world. We also validate the success of our proposal through several simulations and comparisons with a regular architecture, taking into account the optimization of the resources of the devices. Finally, we compare our proposal with other caching techniques published in the related literature. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low-resource communities. That is, it lets communicate spontaneous networks, which are working collaboratively and which have been created on different physical places.Authors want to give thanks to the anonymous reviewers for their valuable suggestions, useful comments, and proofreading of this paper. This work was partially supported by the Ministerio de Educacion y Ciencia, Spain, under Grant no. TIN2008-06441-C02-01, and by the "Ayudas complementarias para proyectos de I+D para grupos de calidad de la Generalitat Valenciana" (ACOMP/2010/005).Lacuesta Gilaberte, R.; Lloret, J.; García Pineda, M.; Peñalver Herrero, ML. (2010). A spontaneous ad hoc network to share www access. EURASIP Journal on Wireless Communications and Networking. 2010:1-16. https://doi.org/10.1155/2010/232083S1162010Preuß S, Cap CH: Overview of spontaneous networking-evolving concepts and technologies. In Rostocker Informatik-Berichte. Volume 24. Fachbereich Informatik der Universit at Rostock; 2000:113-123.Gallo S, Galluccio L, Morabito G, Palazzo S: Rapid and energy efficient neighbor discovery for spontaneous networks. Proceedings of the 7th ACM International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems, October 2004, Venice, ItalyLatvakoski J, Pakkala D, Pääkkönen P: A communication architecture for spontaneous systems. IEEE Wireless Communications 2004, 11(3):36-42. 10.1109/MWC.2004.1308947Zarate Silva VH, De Cruz Salgado EI, Quintana FR: AWISPA: an awareness framework for collaborative spontaneous networks. Proceedings of the 36th ASEE/IEEE Frontiers in Education Conference (FIE '06), October 2006 1-6.Feeney LM, Ahlgren B, Westerlund A: Spontaneous networking: an application-oriented approach to ad hoc networking. IEEE Communications Magazine 2001, 39(6):176-181. 10.1109/35.925687Perkins CE, Bhagwat P: Highly dynamic destination-sequenced distance-vector routing (DSDV) for mobile computers. Proceedings of the Conference on Communications Architectures, Protocols and Applications (SIGCOMM '94), August 1994 234-244.Johnson DB, Maltz DA, Broch J: DSR: The Dynamic Source Routing Protocol for Multihop Wireless Ad Hoc Networks, Ad Hoc Networking. Addison-Wesley Longman Publishing, Boston, Mass, USA; 2001.Perkins C, Belding-Royer E, Das S: Ad hoc on-demand distance vector (AODV) routing. RFC 3561, July 2003Park V, Corson MS: IETF MANET Internet Draft "draft-ietf-MANET-tora-spe03.txt". Novemmer 2000.Viana AC, De Amorim MD, Fdida S, de Rezende JF: Self-organization in spontaneous networks: the approach of DHT-based routing protocols. Ad Hoc Networks 2005, 3(5):589-606.Gilaberte RL, Herrero LP: IP addresses configuration in spontaneous networks. Proceedings of the 9th WSEAS International Conference on Computers, July 2005, Athens, GreeceViana AC, Dias de Amorim M, Fdida S, de Rezende JF: Self-organization in spontaneous networks: the approach of DHT-based routing protocols. Ad Hoc Networks 2005, 3(5):589-606.Alvarez-Hamelin JI, Carneiro Viana A, Dias De Amorim M: Architectural considerations for a self-configuring routing scheme for spontaneous networks.,Tech. Rep. 1 October 2005.Lacuesta R, Peñalver L: Automatic configuration of ad-hoc networks: establishing unique IP link-local addresses. Proceedings of the International Conference on Emerging Security Information, Systems and Technologies (SECURWARE '07), October 2007, Valencia, SpainFoulks EF: Social network therapies and society: an overview. Contemporary Family Therapy 1985, 3(4):316-320.Wang Y, Wu H: DFT-MSN: the delay/fault-tolerant mobile sensor network for pervasive information gathering. Proceedings of the 25th IEEE International Conference on Computer Communications (INFOCOM '06), April 2006Kindberg T, Zhang K: Validating and securing spontaneous associations between wireless devices. In Proceedings of the 6th Information Security Conference (ISC '03), 2003. Springer; 44-53.Al-Jaroodi J: Routing security in open/dynamic mobile ad hoc networks. The International Arab Journal of Information Technology 2007, 4(1):17-25.Stajano F, Anderson RJ: The resurrecting duckling: security issues for ad-hoc wireless networks. 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Proceedings of the 38th Annual Hawaii International Conference on System Sciences (HICSS '05), January 2005, Big Island, Hawaii, USAGokhale S, Dasgupta P: Distributed authentication for peer-to-peer networks. Proceedings of the Symposium on Applications and the Internet Workshops, January 2003 347-353.Capkun S, Buttyán L, Hubaux J-P: Self-organized public-key management for mobile ad hoc networks. IEEE Transactions on Mobile Computing 2003, 2(1):52-64. 10.1109/TMC.2003.1195151Stajano F, Anderson R: The resurrecting duckling security issues for ad-hoc wireless networks. In Proceedings of the 7th International Workshop on Security Protocols, 1999, Berlin, Germany, Lecture Notes in Computer Science. Volume 1796. Springer; 172-194.Balfanz D, Smetters DK, Stewart P, Wong HC: Talking to strangers: authentication in ad-hoc wireless networks. Proceedings of the International Symposium on Network and Distributed Systems Security (NDSS '02), February 2002, San Diego, Calif, USABarbara D, Imielinski T: Sleepers and workaholics: caching strategies in mobile environments. Proceedings of the ACM SIGMOD International Conference on Management of Data, May 1994 1-12.Cao G: A scalable low-latency cache invalidation strategy for mobile environments. IEEE Transactions on Knowledge and Data Engineering 2003, 15(5):1251-1265. 10.1109/TKDE.2003.1232276Hu Q, Lee D: Cache algorithms based on adaptive invalidation reports for mobile environments. Cluster Computing 1998, 1(1):39-50. 10.1023/A:1019012927328Jing J, Elmagarmid A, Helal A, Alonso R: Bit-sequences: an adaptive cache invalidation method in mobile client/server environments. Mobile Networks and Applications 1997, 2(2):115-127. 10.1023/A:1013616213333Kahol A, Khurana S, Gupta S, Srimani P: An efficient cache management scheme for mobile environment. 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IEEE Transactions on Mobile Computing 2005, 4(1):68-83.Wessels D, Claffy K: Internet cache protocol (IC) v.2. http://www.ietf.org/rfc/rfc2186.txtFan L, Cao P, Almeida J, Broder AZ: Summary cache: a scalable wide-area web cache sharing protocol. IEEE/ACM Transactions on Networking 2000, 8(3):281-293. 10.1109/90.851975Dykes SG, Robbins KA: A viability analysis of cooperative proxy caching. Proceedings of the 20th Annual Joint Conference of the IEEE Computer and Communications Societies (INFOCOM '01), April 2001, Anchorage, Alaska, USA 3: 1205-1214.Wessels D, Claffy K: RFC 2186: Internet cache protocol (ICP), version 2. The Internet Engineering Taskforce, September 1997Wessels D, Claffy K: RFC 2187: application of internet cache protocol (ICP), version 2. The Internet Engineering Taskforce, September 1997Ren Q, Dunhan MH: Using semantic caching to manage location dependent data in mobile computing. 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Proceedings of the ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc '01), October 2001, Long Beach, Calif, USA 117-127.Can P, Irani S: Cost-aware WWW proxy caching algorithms. Proceedings of the USENIX Symposium on lnternet Technology and Systems, December 1997Rizzo L, Vicisano L: Replacement policies for a proxy cache. IEEE/ACM Transactions on Networking 2000, 8(2):158-170. 10.1109/90.842139Williams S, Abrams M, Strandridge CR, Abdulla G, Fox EA: Removal policies in network caches for world-wide web documents. Proceedings of the ACM SIGCOMM Conference on Applications, Technologies, Architectures, and Protocols for Computer Communications, August 1996, Palo Alto, Calif, USA 293-305.Hara T: Replica allocation in ad hoc networks with period data update. 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Game theoretic peer selection for resilient peer-to-peer media streaming systems

Peer-to-peer (P2P) media streaming quickly emerges as an important application over the Internet. A plethora of approaches have been suggested and implemented to support P2P media streaming. In our study, we first classified existing approaches and studied their characteristics by looking at three important quantities: number of upstream peers (parents), number of downstream peers (children) and average number of links per peer. We find that in existing approaches, peers are assigned with a fixed number of parents without regard to their contributions, measured by the amount of outgoing bandwidths. Obviously, this is an undesirable arrangement as it leads to highly inefficient use of the P2P links. This observation motivates us to model the peer selection process as a cooperative game among peers. This results in a novel peer selection protocol such that the number of upstream peers of a peer is related to its outgoing bandwidth. Specifically, peers with larger outgoing bandwidth are given more parents, which makes them less vulnerable to peer dynamics. Simulation results show that the proposed protocol improves delivery ratio with similar number of links per peer, comparing with existing approaches in a wide range of settings. © 2008 IEEE.link_to_subscribed_fulltex

Game-theoretic scalable peer-to-peer media streaming

Peer-to-peer media streaming framework has been widely considered as a promising platform for delivering high quality multimedia content on the global scale. A fundamental requirement is that each peer needs to contribute outgoing bandwidth to deliver media packets to its neighbors. Although most existing protocols mandate such contribution, misbehaving peers may still deliberately limit their outgoing bandwidth to conserve their own resources. This would inevitably lead to performance degradation of other well-behaving peers. It is crucial to have an effective incentive mechanism such that peers are encouraged to contribute. In this paper, we formulate two strategic games to model the interactions between server and its immediate peers and between neighboring peers, respectively. We have devised the equilibrium strategies which relate a peer's streaming performance to its contribution. Simulation results show that the proposed game-theoretical incentive mechanism protects well-behaving peers from being exploited by misbehaving counterparts. ©2008 IEEE.link_to_subscribed_fulltex

On energy efficient wireless data access: Caching or not?

We consider a typical wireless data access scenario: a number of mobile clients are interested in a set of data items kept at a common server. A client sends a request to inform the server of its desired data item while the server replies in the common broadcast channel. To study the energy consumption characteristics in such a scenario, we first define a power aware utility function. Based on the utility function, we propose a novel wireless data access scheme, which is a non-cooperative game - wireless data access (WDA) game. Although it does not rely on client caching (without-cache), our theoretical analysis shows that it is not always necessary for clients to send requests to the server. Simulation results confirm that our proposed scheme, compared with a simple always-request one, increases both the utility and lifetime of every client while reducing the number of requests sent, at the cost of slightly larger average query delay. © Springer-Verlag Berlin Heidelberg 2005.link_to_subscribed_fulltex