@article {23628,
	title = {Cache-Centric Video Recommendation: An Approach to Improve the Efficiency of YouTube Caches},
	journal = {ACM Trans. Multimedia Comput. Commun. Appl.},
	volume = {11},
	year = {2015},
	month = {06/2015},
	pages = {1--20},
	publisher = {ACM},
	address = {New York, NY, USA},
	abstract = {In this article, we take advantage of the user behavior of requesting videos from the top of the related list provided by YouTube to improve the performance of YouTube caches. We recommend that local caches reorder the related lists associated with YouTube videos, presenting the cached content above noncached content. We argue that the likelihood that viewers select content from the top of the related list is higher than selection from the bottom, and pushing contents already in the cache to the top of the related list would increase the likelihood of choosing cached content. To verify that the position on the list really is the selection criterion more dominant than the content itself, we conduct a user study with 40 YouTube-using volunteers who were presented with random related lists in their everyday YouTube use. After confirming our assumption, we analyze the benefits of our approach by an investigation that is based on two traces collected from a university campus. Our analysis shows that the proposed reordering approach for related lists would lead to a 2 to 5 times increase in cache hit rate compared to an approach without reordering the related list. This increase in hit rate would lead to reduction in server load and backend bandwidth usage, which in turn reduces the latency in streaming the video requested by the viewer and has the potential to improve the overall performance of YouTube{\textquoteright}s content distribution system. An analysis of YouTube{\textquoteright}s recommendation system reveals that related lists are created from a small pool of videos, which increases the potential for caching content from related lists and reordering based on the content in the cache.},
	keywords = {Caching, recommendation, YouTube},
	issn = {1551-6857},
	doi = {10.1145/2716310},
	url = {http://doi.acm.org/10.1145/2716310},
	author = {Dilip Kumar {Krishnappa} and Zink, Michael and Griwodz, Carsten and Halvorsen, P{\r a}l}
}
@inproceedings {Simula.simula.2052,
	title = {Cache-Centric Video Recommendation: an Approach to Improve the Efficiency of YouTube Caches},
	journal = {Proceedings of the International Conference on Multimedia Systems (MMSys)},
	year = {2013},
	month = {March},
	pages = {261-270},
	publisher = {ACM},
	type = {Conference},
	abstract = {In this paper, we take advantage of the user behavior of re- questing videos from the related list provided by YouTube and the user behavior of requesting videos from the top of this related list to improve the performance of YouTube{\textquoteright}s caches. We recommend a related list reordering approach which modifies the order of the videos shown on the related list based on the content in the cache. The main goal of our reordering approach is to push the contents already in the cache to the top of the related list and push non-cached contents towards the bottom, which increases the likelihood that the already cached content will be chosen by the viewer. We analyze the benefits of our approach by an investigation that is based on two traces collected from an university campus. Our analysis shows that the proposed reordering approach for related list would lead to a 2 to 5 times increase in cache hit rate compared to an approach without reordering the related list. The increase in hit rate would lead to a 5.12\% to 18.19\% reduction in server load or back-end bandwidth usage. This increase in hit rate and reduction in back-end bandwidth reduces the latency in streaming the video requested by the viewer and has the potential to improve the overall performance of YouTube{\textquoteright}s content distribution system. An analysis of YouTube{\textquoteright}s recommendation system reveals that related lists are created from a small pool of videos, which increases the potential for caching content from related lists and reordering based on the content in the cache.},
	keywords = {Conference},
	author = {Dilip Kumar {Krishnappa} and Zink, Michael and Griwodz, Carsten and Halvorsen, P{\r a}l},
	editor = {Griwodz, Carsten}
}
@inproceedings {Simula.simula.2610,
	title = {What Should You Cache?: a Global Analysis on YouTube Related Video Caching},
	journal = {Proceeding of the 23rd ACM Workshop on Network and Operating Systems Support for Digital Audio and Video},
	year = {2013},
	month = {March},
	pages = {31-36},
	publisher = {ACM},
	type = {Annual},
	address = {unknown},
	abstract = {Following advice from the YouTube recommendation system is one of the ways users browse through the videos offered by YouTube. The system presents related videos based on several factors depending on the current video requested. This related videos list can be used by caching infrastructure to reduce network bandwidth consumption. In this paper, we analyze the differences between user-specific recommendation lists. We perform this analysis on 100s of user nodes from all around the world divided into 4 geographical regions using PlanetLab. Based on our analysis, we find that the related videos differ less in the top half (1-10) of the related video list offered by YouTube compared to the bottom half (11-20). Based on our analysis, we suggest that, caching or prefetching of the Top 10 of the related videos is advantageous over a period of time than caching the whole list offered by YouTube.},
	doi = {10.1145/2460782.2460788},
	author = {Dilip Kumar {Krishnappa} and Zink, Michael and Griwodz, Carsten}
}
@article {Zink.2004.1,
	title = {Layer-Encoded Video Streaming: a Proxy{\textquoteright}s Perspective},
	journal = {IEEE Communications Magazine},
	volume = {42},
	number = {8},
	year = {2004},
	month = {aug},
	pages = {96-103},
	author = {Zink, Michael and Schmitt, Jens and Griwodz, Carsten}
}
@inproceedings {zink-mmcn-2003,
	title = {Scalable TCP-Friendly Video Distribution for Heterogeneous Clients},
	journal = {Proceedings of SPIE/ACM Conference on Multimedia Computing and Networking (MMCN)},
	year = {2003},
	month = {jan},
	pages = {102-113},
	publisher = {SPIE},
	type = {Annual},
	isbn = {0-8194-4819-2},
	author = {Zink, Michael and Griwodz, Carsten and Schmitt, Jens and Steinmetz, Ralf},
	editor = {Rajkumar, Ragunathan}
}
@inproceedings {plagemann03b,
	title = {Towards Scalable and Affordable Content Distribution Services},
	journal = {Proceedings of the International Conference on Telecommunications (ConTEL)},
	year = {2003},
	month = {jun},
	pages = {307-314},
	publisher = {IEEE},
	type = {Annual},
	isbn = {953-184-052-0},
	author = {Plagemann, Thomas and Goebel, Vera and Griwodz, Carsten and Halvorsen, P{\r a}l and Mathey, Laurent and Zink, Michael},
	editor = {Matija{\v s}evi{\'c}, Maja and Igor S. {Pandzic}}
}
@inproceedings {zink-mmcn-2002,
	title = {Exploiting the Fair Share to Smoothly Transport Layered Encoded Video Into Proxy Caches},
	journal = {Proceedings of SPIE/ACM Conference on Multimedia Computing and Networking (MMCN)},
	year = {2002},
	month = {dec},
	pages = {61-72},
	publisher = {SPIE},
	type = {Annual},
	isbn = {0-8194-4413-8},
	author = {Zink, Michael and Griwodz, Carsten and Schmitt, Jens and Steinmetz, Ralf},
	editor = {Martin G. {Kienzle} and Prashant J. {Shenoy}}
}
@inproceedings {griwodz-zink-2001,
	title = {Dynamic Data Path Reconfiguration},
	journal = {M3W: Proceedings of the International Workshop on Multimedia Middleware},
	year = {2001},
	pages = {72-75},
	publisher = {ACM Press},
	type = {Workshop},
	address = {Ottawa, Ontario, Canada},
	isbn = {1-58113-396-0},
	author = {Griwodz, Carsten and Zink, Michael},
	editor = {Nicolas D. {Georganas} and Popescu-Zeletin, Radu}
}
@inproceedings {Simula.ND.343,
	title = {KOM Player - a Platform for Experimental VoD Research},
	journal = {9th Dortmunder Fernsehseminar},
	volume = {167},
	year = {2001},
	pages = {287-293},
	publisher = {ITG},
	type = {Workshop},
	address = {Frankfurt},
	isbn = {?},
	author = {Zink, Michael and Griwodz, Carsten and Steinmetz, Ralf},
	editor = {Schr{\"o}der R. {Kays}}
}
@inproceedings {zink01,
	title = {KOM Player - a Platform for Experimental VoD Research},
	journal = {IEEE Symposium on Computers and Communications (ISCC)},
	year = {2001},
	note = {(Hammamet, Tunisia)},
	month = {jul},
	pages = {370-375},
	publisher = {IEEE Press},
	type = {Annual},
	abstract = {In contrast to audio which is often streamed as complete music titles or even as a life feed from a radio station, video in today\&$\#$39;s Internet is almost only available as small clips and pre-generated programs. Although some of the problems concerning AV streaming are reasonably solved right now, some work in fields like wide area distribution systems need further investigation to make applications like \&ldquo;true video-on-demand\&rdquo; work. Our research and the one of many others is focused on problems that have to be solved to make application like VoD work in the Internet. It is mainly concerned with wide area distribution. We present a platform for experimental VoD research which is thought to support researchers working on VoD and wide area distribution for audio and video content. This platform offers researchers the possibility to implement their ideas without building a complete streaming environment and in addition allows the combination of different implementations. After motivating the development of our platform we present the design of our platform, give an overview of the actual implementation and the existing components that we have already built. Finally, example scenarios for the use of our platform in research are given},
	isbn = {0-7695-1177-5},
	doi = {10.1109/ISCC.2001.935401},
	author = {Zink, Michael and Griwodz, Carsten and Steinmetz, Ralf}
}
@inproceedings {griwodz-2000b,
	title = {Perceived Consistency},
	journal = {Proc. of the ACS/IEEE Int{\textquoteright}l. Conf. on Computer Systems and Applications (AICCSA)},
	year = {2001},
	note = {(Beirut, Lebanon)},
	month = {jun},
	pages = {260-266},
	publisher = {ACS},
	type = {Annual},
	abstract = {Quality of service guarantees for multimedia communication systems have been considered on several abstraction levels. In the multimedia networking field it is typical to identify the minimal QoS requirements of an application to save resources by guaranteeing its functionality. Many of these applications can operate in spite of an imperfect delivery of media data, while other applications such as distributed databases or distributed file systems consider perfect QoS necessary but accept delay. The basic problems of the latter is the consistency of their data, while the former require a consistent perception of the content. More generically, both QoS requirements can be interpreted as a problem of maintaining a consistent system state. Consequently we assume that many distributed applications, including most distributed multimedia applications, can fulfil their tasks in spite of imperfect consistency. Since the application requirements differ widely, the elements that make up \&ldquo;consistency\&rdquo; must be separated and classified. This paper introduces Consistency QoS and proposes a classification of elements that determine an application\&$\#$39;s consistency requirements. The low level QoS requirements that these separate parameters rely on are shown, and example parameter sets for application classes are given},
	isbn = {0-7695-1165-1},
	doi = {10.1109/AICCSA.2001.933986},
	author = {Griwodz, Carsten and Liepert, Michael and El-Saddik, Abdulmotaleb and On, Giwon and Zink, Michael}
}
@inproceedings {on01,
	title = {Replication for a Distributed Multimedia System},
	journal = {International Conferance on Parallel and Distributed Systems (ICPADS)},
	year = {2001},
	month = {jun},
	pages = {37-42},
	publisher = {IEEE},
	type = {Annual},
	isbn = {0-7695-1153-8},
	author = {On, Giwon and Zink, Michael and Liepert, Michael and Griwodz, Carsten and Schmitt, Jens and Steinmetz, Ralf}
}
@inproceedings {Simula.ND.339,
	title = {Associating Network Flows With User and Application Information},
	journal = {Proc. of ACM workshops on Multimedia},
	year = {2000},
	note = {(Los Angeles, CA, USA)},
	month = {October},
	pages = {149-152},
	publisher = {ACM},
	type = {Workshop},
	abstract = {The concept of authenticating users e.g. by means of a login process is very well established and there is no doubt that it is absolutely necessary and helpful in a multiuser environment. Unfortunately specific information about a user originating a data stream or receiving it, is often no longer available at the traversed network nodes. This applies to the even more specific question of what application is used as well. Routers, gateways or firewalls usually have to base their classification of data on IP header inspection or have to try to extract information from the packets payload. We present an approach that works transparently and allows to associate user and application specific information with IP data streams by only slightly modifying components of the operating system environment and infrastructure components. On top of this framework we show usage scenarios for dedicatedly placing copyright information in media content and for an enhancement of the interoperation with the security infrastructure.},
	isbn = {1-58113-311-1},
	doi = {http://doi.acm.org/10.1145/357744.357914},
	author = {Ackermann, Ralf and Roedig, Utz and Zink, Michael and Griwodz, Carsten and Steinmetz, Ralf},
	editor = {Ghandeharizadeh, Shahram and Chang, Shih-Fu and Fischer, Stephen and Konstan, Joseph and Nahrstedt, Klara}
}
@misc {23626,
	title = {LC-RTP (loss collection RTP): reliability for video caching in the Internet},
	year = {2000},
	publisher = {IEEE},
	abstract = {The increasing amount of audio-visual (AV) content that is offered by web sites leads to a network bandwidth and storage capacity problem. Caching is one of the techniques that can ease this problem. But even in a caching system the distribution of data (i.e. the AV content) should be bandwidth-efficient. Furthermore the delivery to the end-user must regard the restrictions implied by real-time data. This paper describes LC-RTP, an efficient and simple reliable multicast protocol that complies with RTP. Its deployment would require neither changes to the network infrastructure nor to existing end-user presentation software. It provides lossless transmission of AV content into cache servers and concurrently, lossy real-time delivery to end-users using multicast. It achieves reliability by retransmission. The traffic increase is minimal because the transmission of the AV content and any caching will take place while the end-user is served. Support for multicast in the distribution system ensures that all cache servers of a multicast group can cache an AV content while transmitting it to a consumer. Finally we present the results of long distance file transmissions in order to show that LC-RTP performs well and meets the requirements for lossless transmission of AV content},
	keywords = {audio-visual, Bandwidth, cache storage, Communication industry, Delay, file transmissions, Intelligent networks, Internet, LC-RTP, loss collection RTP, multicast protocol, multimedia communication, Network servers, Propagation losses, Protocols, reliability, Streaming media, Telecommunication network reliability, transport protocols, video caching},
	doi = {10.1109/PADSW.2000.884594},
	url = {http://dx.doi.org/10.1109/PADSW.2000.884594},
	author = {Zink, Michael and Jonas, A. and Griwodz, Carsten and Steinmetz, R.}
}
@inproceedings {griwodz-zink-2000,
	title = {Multicast for Savings in Cache-Based Video Distribution},
	journal = {Proceedings of SPIE/ACM Conference on Multimedia Computing and Networking (MMCN)},
	volume = {3969},
	number = {26},
	year = {2000},
	note = {(San Jose, CA, USA)},
	month = {dec},
	pages = {26-35},
	publisher = {SPIE},
	type = {Annual},
	abstract = {Internet video-on-demand (VoD) today streams videos directly from server to clients, because re-distribution is not established yet. Intranet solutions exist but are typically managed centrally. Caching may overcome these management needs, however existing web caching strategies are not applicable because they work in different conditions. We propose movie distribution by means of caching, and study the feasibility from the service providers{\textquoteright} point of view. We introduce the combination of our reliable multicast protocol LCRTP for caching hierarchies combined with our enhancement to the patching technique for bandwidth friendly True VoD, not depending on network resource guarantees.},
	isbn = {0-8194-3587-2},
	doi = {10.1117/12.373532},
	author = {Griwodz, Carsten and Zink, Michael and Liepert, Michael and On, Giwon and Steinmetz, Ralf},
	editor = {Nahrstedt, Klara and Feng, Wu-chi}
}
@article {Griwodz.2000.1,
	title = {Tune to Lambda-Patching},
	journal = {Performance Evaluation},
	volume = {27},
	number = {4},
	year = {2000},
	month = {mar},
	pages = {20-26},
	author = {Griwodz, Carsten and Liepert, Michael and Zink, Michael and Steinmetz, Ralf}
}
@inproceedings {Simula.ND.337,
	title = {Distributed Media Server for the Support of Multimedia Teaching},
	journal = {Multimedia Systems and Applications II},
	volume = {3845},
	number = {452},
	year = {1999},
	note = {(Boston, MA, USA)},
	month = {Sept.},
	pages = {452-463},
	publisher = {SPIE},
	type = {Annual},
	abstract = {One major problem of using multimedia material in lecturing is the trade-off between actuality of the content and quality of the presentations. A frequent need for content refreshment exists, but high quality presentations can not be authored by the individual teacher alone at the required rate. Several past and current projects have had the goal of developing so-called learning archives, a variation of digital libraries. On demand, these deliver material with limited structure to students. For lecturing, these systems provide just as insufficient service as the unreliable WWW. Based on our system HyNoDe [HYN97] we address these issues in our distributed media server built of {\textquoteright}medianodes.{\textquoteright} We add content management that addresses teachers{\textquoteright} needs and provide guaranteed service for connected as well as disconnected operation of their presentation systems. Medianode aims at a scenario for non-real-time, shared creation and modification of presentations and presentation elements. It provides user authentication, administrative roles and authorization mechanisms. It requires an understanding of consistency, versioning and alternative content tailored to lecturing. To allow for predictable presentation quality, medianode provides application level QoS supporting alternative media and alternative presentations. Viable presentation tracks are dynamically generated based on user requests, user profiles and hardware profiles. For machines that are removed from the system according to a schedule, the systems guarantees availability of consistent, complete tracks of selected presentations at disconnect time. In this paper we present the scope of the medianode project and afterwards its architecture, following the realization steps.},
	isbn = {9780819434388},
	doi = {10.1117/12.371230},
	author = {Liepert, Michael and Griwodz, Carsten and On, Giwon and Zink, Michael and Steinmetz, Ralf},
	editor = {Andrew G. {Tescher} and Vasudev, Bhaskaran and Michael {Bove, Jr.} and Derryberry, Barbara}
}
@inproceedings {griwodz-1999,
	title = {Position Paper: Internet VoD Cache Server Design},
	journal = {Proceedings of the ACM International Multimedia Conference (ACM MM)},
	year = {1999},
	note = {(Orlando, FL, USA)},
	month = {oct},
	pages = {123-126},
	publisher = {ACM Press},
	type = {Annual},
	isbn = {1-58113-239-5},
	doi = {http://doi.acm.org/10.1145/319878.319911},
	author = {Griwodz, Carsten and Zink, Michael and Liepert, Michael and Steinmetz, Ralf},
	editor = {Scott Stevens Jo {Buford}}
}
