Search results for "video-servers"

Hits ?▲	Authors	Title	Venue	Year	Link	Author keywords
54	Constantinos Vassilakis, Michael Paterakis, Peter Triantafillou	Video Placement and Configuration of Distributed Video Servers on Cable TV Networks.	Multim. Syst.	2000	DBLP DOI BibTeX RDF	Distributed VOD systems, Program placement, HFC distribution networks
42	Chen-Yu Chen, Jia-Ching Wang, Jhing-Fa Wang	Efficient news video querying and browsing based on distributed news video servers.	IEEE Trans. Multim.	2006	DBLP DOI BibTeX RDF
42	Ariel Cohen 0003, Walter A. Burkhard	Segmented Information Dispersal (SID) Data Layouts for Digital Video Servers.	IEEE Trans. Knowl. Data Eng.	2001	DBLP DOI BibTeX RDF	separated difference sets, Algorithms, data structures, video servers, disk arrays, declustering
40	Ing-Ray Chen, Sheng-Tun Li, I-Ling Yen	Adaptive QoS Control Based on Benefit Optimization for Video Servers Providing Differentiated Services.	Multim. Tools Appl.	2005	DBLP DOI BibTeX RDF	quality of service (QoS), admission control, disk scheduling, video servers, data placement, streaming video, QoS negotiation
40	Jamel Gafsi, Ernst W. Biersack	Modeling and Performance Comparison of Reliability Strategies for Distributed Video Servers.	IEEE Trans. Parallel Distributed Syst.	2000	DBLP DOI BibTeX RDF	Distributed video servers, performance and cost analysis, Markov chains, reliability modeling, SHARPE
40	Ernst W. Biersack, Frédéric Thiesse	Statistical Admission Control in Video Servers with Variable Bit-Rate Streams and Constant Time Length Retrieva.	EUROMICRO	1996	DBLP DOI BibTeX RDF	statistical admission control, constant time length retrieval, server disk, statistical service guarantee, deterministic service guarantee, quality of service, performance evaluation, video servers, network servers, disk storage, variable bit rate streams, I/O bandwidth
39	Jonathan C. L. Liu, David Hung-Chang Du, Simon S. Y. Shim, Jenwei Hsieh, Mengjou Lin	Design and Evaluation of a Generic Software Architecture for On-Demand Video Servers.	IEEE Trans. Knowl. Data Eng.	1999	DBLP DOI BibTeX RDF	system integration and management, distributed multimedia systems, Experimental systems
38	Meng Guo 0005, Mostafa H. Ammar, Ellen W. Zegura	V3: A Vehicle-to-Vehicle Live Video Streaming Architecture.	PerCom	2005	DBLP DOI BibTeX RDF
37	Olav Sandstå, Stein Langørgen, Roger Midtstraum	Video Server on an ATM Connected Cluster of Workstations.	SCCC	1997	DBLP DOI BibTeX RDF	ATM connected cluster of workstations, virtual video documents, Elvira video server, asynchronous transfer mode, digital video, video server, UNIX workstations
36	Song Wu 0001, Hai Jin 0001, Guang Tan	Symmetrical Declustering: A Load Balancing and Fault Tolerant Strategy for Clustered Video Servers.	ICCSA (1)	2003	DBLP DOI BibTeX RDF
36	Eduardo Magaña, Javier Aracil 0001, Jesús E. Villadangos	Packet Video Broadcasting with General-Purpose Operating Systems in an Ethernet.	Multim. Tools Appl.	2004	DBLP DOI BibTeX RDF	packet video broadcasting, general-purpose video servers, Ethernet
35	Leonardo Bidese de Pinho, Claudio Luis de Amorim, Edison Ishikawa	GloVE: A Distributed Environment for Low Cost Scalable VoD Systems.	SBAC-PAD	2002	DBLP DOI BibTeX RDF
33	Song Wu 0001, Hai Jin 0001	Symmetrical Pair Scheme: A Load Balancing Strategy to Solve Intra-Movie Skewness for Parallel Video Servers.	IPDPS	2002	DBLP DOI BibTeX RDF	Symmetrical Pair Scheme, Intra-movie Skewness, Load Balance, Parallel Video Server
32	Ke Shen 0002, Edward J. Delp	A fast algorithm for video parsing using MPEG compressed sequences.	ICIP	1995	DBLP DOI BibTeX RDF	MPEG compressed sequences, digital video applications, video data processing, DC coefficient image, parsing algorithm speed, digital libraries, data compression, image sequences, video coding, image reconstruction, image reconstruction, discrete cosine transforms, histograms, motion compensation, fast algorithm, transform coding, video servers, scene changes detection, video parsing, execution speed
32	Prashant J. Shenoy, Harrick M. Vin	Efficient Support for Interactive Operations in Multi-Resolution Video Servers.	Multim. Syst.	1999	DBLP DOI BibTeX RDF	Multi-resolution video servers, Multi-resolution playback, Rewind, Scalable compression, Disk arrays, Fast-forward, Scan operations
32	Jamel Gafsi, Ernst W. Biersack	Performance and Reliability Study for Distributed Video Servers: Mirroring or Parity?.	ICMCS, Vol. 2	1999	DBLP DOI BibTeX RDF	Video Servers, Reliability Modeling, Distributed Multimedia
32	Edward Y. Chang, Avideh Zakhor	Cost Analyses for VBR Video Servers.	IEEE Multim.	1996	DBLP DOI BibTeX RDF	admission control, cost, video servers, disk arrays, data placement, VBR, video storage
32	Prashant J. Shenoy, Harrick M. Vin	Efficient Support for Scan Operations in Video Servers.	ACM Multimedia	1995	DBLP DOI BibTeX RDF	video servers, disk arrays, scan operations
31	Yong Wei, Suchendra M. Bhandarkar, Kang Li 0001	Video personalization in resource-constrained multimedia environments.	ACM Multimedia	2007	DBLP DOI BibTeX RDF	multiple-choice multi-dimensional knapsack problem, request aggregation, video personalization, video summarization
31	Tzi-cker Chiueh, Michael Vernick	An Empirical Study of Admission Control Strategies in Video Servers.	ICPP	1998	DBLP DOI BibTeX RDF
29	Hiroyuki Kimiyama, Shuichi Itoh	Method of predicting number of on-demand video requests using time series data for video cache system.	MoMM	2008	DBLP DOI BibTeX RDF	requests prediction, video-on-demand, cache algorithm
29	Wei-hsiu Ma, David Hung-Chang Du	Frame Selection for Dynamic Caching Adjustment in Video Proxy Servers.	Multim. Tools Appl.	2004	DBLP DOI BibTeX RDF	frame selection, video smoothing, video streaming, proxy server, video caching
28	Minseok Song 0001	Adaptive Data Retrieval for Load Sharing in Clustered Video Servers.	MMM (1)	2007	DBLP DOI BibTeX RDF
28	James Zijun Wang, Ratan K. Guha	Data allocation algorithms for distributed video servers.	ACM Multimedia	2000	DBLP DOI BibTeX RDF
27	Toshiaki Suzuki, Mariko Yamada, Takehiro Urano, Keiro Muro, Toshiyuki Odaka	Personalized MPEG2 Video-Data Transmission System.	ICIW	2008	DBLP DOI BibTeX RDF	Personalized Video, Multi-angle Video, MPEG, Interactive TV
27	Joseph Kee-Yin Ng, Karl R. P. H. Leung, Calvin Kin-Cheung Hui	A QoS-Enabled Transmission Scheme for MPEG Video Streaming.	Real Time Syst.	2005	DBLP DOI BibTeX RDF	MPEG video streaming, transmission scheme, quality of services, video on demand, QoS control
26	Minseok Song 0001, Heonshik Shin	Replica Striping for Multi-resolution Video Servers.	IDMS/PROMS	2002	DBLP DOI BibTeX RDF
26	Klaus Breidler, Harald Kosch, László Böszörményi	A Comparative Study of Selected Parallel Video Servers.	DEXA Workshops	2000	DBLP DOI BibTeX RDF
26	Dzung T. Hoang, Jeffrey Scott Vitter	Multiplexing VBR Video Sequences onto a CBR Channel with Lexicographic Optimization.	ICIP (1)	1997	DBLP DOI BibTeX RDF	VBR video sequences multiplexing, CBR channel, lexicographic optimization, multiple VBR video streams, maximum distortion, multiplexing model, single-stream CBR bit allocation, MPEG video buffering verifier, image quality, multiplexing, video servers, statistical multiplexing
24	Minseok Song 0001, Heonshik Shin	Replication and retrieval strategies for resource-effective admission control in multi-resolution video servers.	Multim. Tools Appl.	2006	DBLP DOI BibTeX RDF	Multi-resolution video severs, Striping unit size, Replication, Admission control
24	Minseok Song 0001	Dynamic Buffer Allocation for Conserving Disk Energy in Clustered Video Servers Which Use Replication.	EUC	2006	DBLP DOI BibTeX RDF
24	Akihito Hiromori, Hirozumi Yamaguchi, Keiichi Yasumoto, Teruo Higashino, Kenichi Taniguchi	A Selection Technique for Replicated Multicast Video Servers.	ICPP	2002	DBLP DOI BibTeX RDF
24	Eenjun Hwang, B. Prabhakaran 0001	Application-Layer Protocol for Collaborative Multimedia Presentations.	Multim. Tools Appl.	2003	DBLP DOI BibTeX RDF	collaborative multimedia presentations, retrieval scheduling, application sub-layer, collaborative resource negotiation, multimedia presentations
23	Michael Kozuch, Wayne H. Wolf, Andrew Wolfe	An Experimental Analysis of Digital Video Library Servers.	Multim. Syst.	2000	DBLP DOI BibTeX RDF	Non-linear video, Video walk-through, Performance analysis, Video server, Video library
23	Walid G. Aref, Ibrahim Kamel, Shahram Ghandeharizadeh	Disk Scheduling in Video Editing Systems.	IEEE Trans. Knowl. Data Eng.	2001	DBLP DOI BibTeX RDF
22	David W. Brubeck, Lawrence A. Rowe	Hierarchical Storage Management in a Distributed VOD System.	IEEE Multim.	1996	DBLP DOI BibTeX RDF
22	Minseok Song 0001	An Adaptive Data Retrieval Scheme for Reducing Energy Consumption in Mirrored Video Servers.	International Conference on Computational Science (1)	2006	DBLP DOI BibTeX RDF
22	Dafu Deng, Hai Jin 0001, Xiaofei Liao, Hao Chen 0002	CBBS: A Content-Based Bandwidth Smoothing Scheme for Clustered Video Servers.	NPC	2004	DBLP DOI BibTeX RDF
22	Minseok Song 0001, Heonshik Shin, Naehyuck Chang	A QoS Negotiation Scheme for Efficient Failure Recovery in Multi-resolution Video Servers.	IDMS	2001	DBLP DOI BibTeX RDF
22	Suneuy Kim, Kim Hang Thi Tran	Supporting Scalable and Cooperative Interval Caching in a Clustered Video Server.	NCA	2007	DBLP DOI BibTeX RDF
21	Kai-Tat Fung, Wan-Chi Siu	DCT-based video downscaling transcoder using split and merge technique.	IEEE Trans. Image Process.	2006	DBLP DOI BibTeX RDF
20	Hao-Hua Chu, Klara Nahrstedt	Dynamic Multi-Path Communication for Video Traffic.	HICSS (1)	1997	DBLP DOI BibTeX RDF
20	Minseok Song 0001, Jaewoo Kim, Bumsun Lee	Energy-Aware Interval Caching for Mirrored Video Servers.	ISM	2008	DBLP DOI BibTeX RDF
20	Minseok Song 0001	Energy-aware data prefetching for multi-speed disks in video servers.	ACM Multimedia	2007	DBLP DOI BibTeX RDF
20	Min-You Wu, Wei Shu, Karthikeyan Samuthiram	Optimal Scheduling for Normal and Interactive Operations in Parallel Video Servers.	COMPSAC	1997	DBLP DOI BibTeX RDF	normal playout, interactive operations, scheduling, performance, parallel video server
19	Fei Xie, Kien A. Hua, Ning Jiang	Achieving True Video-on-Demand Service in Multi-Hop WiMax Mesh Networks.	LCN	2007	DBLP DOI BibTeX RDF	Simulation, Algorithm, Wireless Mesh networks, VoD, WiMax, Cross-Layer Design
18	Eenjun Hwang, B. Prabhakaran 0001, V. S. Subrahmanian	Presentation Planning for Distributed VoD Systems.	IEEE Trans. Knowl. Data Eng.	2002	DBLP DOI BibTeX RDF	Distributed VoD, presentation plan, optimal presentation, video server
18	Roger Zimmermann, Shahram Ghandeharizadeh	Highly available and heterogeneous continuous media storage systems.	IEEE Trans. Multim.	2004	DBLP DOI BibTeX RDF
18	Dayoung Lee, Jungwoo Lee, Minseok Song 0002	Video Quality Adaptation for Limiting Transcoding Energy Consumption in Video Servers.	IEEE Access	2019	DBLP DOI BibTeX RDF
18	Yin-Fu Huang, Hung-Ming Ho	Pinned demand paging based on the access frequency of video files in video servers.	J. Syst. Softw.	2005	DBLP DOI BibTeX RDF
18	Sheau-Ru Tong, Yuan-Tse Yu, Chung-Ming Huang	A video caching policy for providing differentiated service grades and maximizing system revenue in hierarchical video servers.	J. Syst. Softw.	2004	DBLP DOI BibTeX RDF
18	Kiyoshi Tanaka, Hideki Sakamoto, Hideharu Suzuki, Kazutoshi Nishimura	Performance improvements of large-scale video servers by video segment allocation.	Syst. Comput. Jpn.	2004	DBLP DOI BibTeX RDF
18	Chow-Sing Lin, Min-You Wu, Wei Shu	Efficient Algorithms for Slot-Scheduling and Cycle-Scheduling of Video Streams on Clustered Video Servers.	Multim. Tools Appl.	2001	DBLP DOI BibTeX RDF
18	Joseph Kee-Yin Ng, Shu Hua Xiong	The Design and Implementation of Video Servers in Video-on-Demand Systems.	Scalable Comput. Pract. Exp.	1999	DBLP BibTeX RDF
18	Chow-Sing Lin, Min-You Wu, Wei Shu	Efficient Algorithms for Slot-Scheduling and Cycle-Scheduling of Video Streams on Parallel Video Servers.	IMSA	1999	DBLP BibTeX RDF
18	Seungyup Paek, Shih-Fu Chang	High Performance Digital Video Servers: Storage and Retrieval of Compressed Scalable Video.	Adv. Comput.	1998	DBLP DOI BibTeX RDF
18	Niko Färber, Bernd Girod	Robust H.263 Compatible Video Transmission for Mobile Access to Video Servers.	ICIP (2)	1997	DBLP DOI BibTeX RDF
18	Eunsam Kim, Taeck-Geun Kwon, Yunmook Nah, Sukho Lee	Supporting Dynamic Relocation of Video Data in Disk-Array-Based Video Servers.	DASFAA	1997	DBLP BibTeX RDF
18	Miguel Boavida, Susana Cabaço, Nuno Correia 0001	VideoZapper: A System for Delivering Personalized Video Content.	Multim. Tools Appl.	2005	DBLP DOI BibTeX RDF	personalized video, editing rules, metadata, video servers
18	Joep Aerts, Jan H. M. Korst, Frits C. R. Spieksma, Wim F. J. Verhaegh, Gerhard J. Woeginger	Random Redundant Storage in Disk Arrays: Complexity of Retrieval Problems.	IEEE Trans. Computers	2003	DBLP DOI BibTeX RDF	Random redundant storage, load balancing, complexity analysis, video servers
18	Senthil Sengodan, Victor O. K. Li	DIVeR: A Dynamic Interactive Video Retrieval Protocol for Disk Array Based Servers.	ICMCS, Vol. 2	1999	DBLP DOI BibTeX RDF	MPEG, video servers, VOD
18	Farshid Arman	Tape-Less Video Technologies: Issues in Workflow Transitions.	ICMCS, Vol. 1	1999	DBLP DOI BibTeX RDF	Media Asset Management, DataBases, workflow, video servers, HSM
18	Rajesh Krishnan, Dinesh Venkatesh, Thomas D. C. Little	A Failure and Overload Tolerance Mechanism for Continuous Media Servers.	ACM Multimedia	1997	DBLP DOI BibTeX RDF	clustered video servers, content insertion, interactive video-on-demand, overload tolerance, rate adaptive stream merging, stream clustering, fault tolerance, caching
18	Baruch Awerbuch, Rainer Gawlick, Frank Thomson Leighton, Yuval Rabani	On-line Admission Control and Circuit Routing for High Performance Computing and Communication	FOCS	1994	DBLP DOI BibTeX RDF	greedy-based approaches, on-line admission control, circuit routing, high performance communication, virtual circuit routing, real-lime database servers, lower bounds, high performance computing, hypercubes, trees, upper bounds, optimal algorithms, arrays, video-servers
17	Niels Haering, Péter L. Venetianer, Alan J. Lipton	The evolution of video surveillance: an overview.	Mach. Vis. Appl.	2008	DBLP DOI BibTeX RDF	Object-based video segmentation, Object recognition, Video surveillance, Visual tracking, Target detection, Vision system, Surveillance system, Scene segmentation
17	Jiang Yu, Chun Tung Chou, Zongkai Yang, Xu Du, Tai Wang	A dynamic caching algorithm based on internal popularity distribution of streaming media.	Multim. Syst.	2006	DBLP DOI BibTeX RDF	Internal popularity, Proxy caching, Streaming video, Segment-based caching, Zipf-like distribution
17	Hani Sorial, William E. Lynch, André Vincent	Joint transcoding of multiple MPEG video bitstreams.	ISCAS (4)	1999	DBLP DOI BibTeX RDF
16	Cheng-Hsin Hsu, Mohamed Hefeeda	Optimal Coding of Multilayer and Multiversion Video Streams.	IEEE Trans. Multim.	2008	DBLP DOI BibTeX RDF
16	Zhe Xiang, Qian Zhang 0001, Wenwu Zhu 0001	Cache replacement and server selection for video proxy across wireless Internet.	ISCAS (2)	2003	DBLP DOI BibTeX RDF
16	Jakob Walla, Mario Ruthmair, Günther R. Raidl	Solving a Video-Server Load Re-Balancing Problem by Mixed Integer Programming and Hybrid Variable Neighborhood Search.	Hybrid Metaheuristics	2009	DBLP DOI BibTeX RDF
14	Rabin Karki, Thangam Seenivasan, Mark Claypool, Robert E. Kinicki	Performance analysis of home streaming video using Orb.	NOSSDAV	2010	DBLP DOI BibTeX RDF	video, streaming, orb
14	Jiang Yu, Xu Du, Tai Wang, Chun Tung Chou	Internal popularity of streaming video and its implication on caching.	AINA (1)	2006	DBLP DOI BibTeX RDF
14	Yuka Kato, Katsuya Hakozaki	A Proposal of a QoS Control Method for Digital Video Libraries.	MDIC	2001	DBLP DOI BibTeX RDF
14	Suneuy Kim, Chita R. Das	A Reliable Statistical Admission Control Strategy for Interactive Video-on-Demand Servers with Interval Caching.	ICPP	2000	DBLP DOI BibTeX RDF	VCR operations, Admission control, Video-On-Demand, analytical model, interval caching
14	Wei Xiong, Xiuyan Jiang, Dejian Ye	Disk I/O based load balancing in VOD system.	ICIS	2009	DBLP DOI BibTeX RDF	cache hit ratio, load balancing, VOD, disk I/O
14	Xiaofei Liao, Hai Jin 0001	Clusters-Based Distributed Streaming Services with Fault-Tolerant Schemes.	PCM (3)	2004	DBLP DOI BibTeX RDF
14	Andrea Calvagna, Antonio Puliafito, Orazio Tomarchio	Design of a Media Service Provider Architecture for the Internet.	ISCC	2000	DBLP DOI BibTeX RDF
14	Shahram Ghandeharizadeh, Seon Ho Kim	A Comparison of Alternative Continuous Display Techniques with Heterogeneous Multi-Zone Disks.	CIKM	1999	DBLP DOI BibTeX RDF
14	Jinhui Song, Bo-Rong Chen, Bowen Song, Anyu Ying, Yih-Chun Hu	FlowBot: A Learning-Based Co-bottleneck Flow Detector for Video Servers.	ICNP	2023	DBLP DOI BibTeX RDF
14	Jungwoo Lee, Hwangje Han, Sungjin Lee, Minseok Song 0002	Lifetime-aware solid-state disk (SSD) cache management for video servers.	Multim. Syst.	2019	DBLP DOI BibTeX RDF
14	Edenilson Jônatas dos Passos, Adriano Fiorese	Aequilibrium: MPEG-DASH video servers load balancing approaches with software-defined networking.	WebMedia	2019	DBLP DOI BibTeX RDF
14	Minseok Song 0002	Minimizing Power Consumption in Video Servers by the Combined Use of Solid-State Disks and Multi-Speed Disks.	IEEE Access	2018	DBLP DOI BibTeX RDF
14	Obinna Izima, Ruairí de Fréin, Mark Davis	Evaluating Load Adjusted Learning Strategies for Client Service Levels Prediction from Cloud-hosted Video Servers.	AICS	2018	DBLP BibTeX RDF
14	Junwoo Lee, Minseok Song	Cache Management for Video Servers by the Combined Use of DRAM and SSD.	ISM	2016	DBLP DOI BibTeX RDF
14	Minseok Song 0002, Yeongju Lee, Euiseok Kim	Saving disk energy in video servers by combining caching and prefetching.	ACM Trans. Multim. Comput. Commun. Appl.	2014	DBLP DOI BibTeX RDF
14	Chien-Chung Ho, Hui-Wen Chen, Yuan-Hao Chang 0001, Yu-Ming Chang, Po-Chun Huang, Tei-Wei Kuo, David Hung-Chang Du	Energy-aware data placement strategy for SSD-assisted streaming video servers.	NVMSA	2014	DBLP DOI BibTeX RDF
14	Roberto Fratini, Marco Savi, Giacomo Verticale, Massimo Tornatore	Using replicated video servers for VoD traffic offloading in integrated metro/access networks.	ICC	2014	DBLP DOI BibTeX RDF
14	Jim Summers, Tim Brecht, Derek L. Eager, Tyler Szepesi, Ben Cassell, Bernard Wong 0001	Automated Control of Aggressive Prefetching for HTTP Streaming Video Servers.	SYSTOR	2014	DBLP DOI BibTeX RDF
14	Sudhir N. Dhage, B. B. Meshram	Design and implementation of video servers for VoD system.	Int. J. Cloud Comput.	2013	DBLP DOI BibTeX RDF
14	Minseok Song 0002, Yeongju Lee, Euiseok Kim	Data prefetching to reduce energy use by heterogeneous disk arrays in video servers.	NOSSDAV	2013	DBLP DOI BibTeX RDF
14	Luis J. de la Cruz Llopis, Andrés Vázquez Rodas, Emilio Sanvicente Gargallo, Mónica Aguilar-Igartua	Load splitting in clusters of video servers.	Comput. Commun.	2012	DBLP DOI BibTeX RDF
14	Mingfu Li, Hsun-Hao Yang	CEA: A Cyclic Expansion Algorithm for data migration in parallel video servers.	J. Parallel Distributed Comput.	2012	DBLP DOI BibTeX RDF
14	Manjong Kim, Minseok Song 0001	Saving Energy in Video Servers by the Use of Multispeed Disks.	IEEE Trans. Circuits Syst. Video Technol.	2012	DBLP DOI BibTeX RDF
14	SeongKi Kim, Ha Yoon Song, Sang-Yong Han	ZipfAllocation: an algorithm for static allocation of movies in a cluster of video servers.	Softw. Pract. Exp.	2011	DBLP DOI BibTeX RDF
14	Vicent Cholvi, Juan Segarra	Analysis and placement of storage capacity in large distributed video servers.	Comput. Commun.	2008	DBLP DOI BibTeX RDF
14	Péter Kárpáti	Designing and scaling proactive, self-organizing video servers: a formal and a simulation model.		2008	RDF
14	Suneuy Kim, Chita R. Das	An analytical model for interval caching in interactive video servers.	J. Netw. Comput. Appl.	2007	DBLP DOI BibTeX RDF
14	SeongKi Kim, Sangyong Han	The Globally Scalable Architecture for Heterogeneous Video Servers without any Modification.	WEBIST (1)	2006	DBLP BibTeX RDF
14	Minseok Song 0001, Heonshik Shin	Minimizing the Buffer Size in Fault-Tolerant Video Servers for VBR Streams.	IEICE Trans. Inf. Syst.	2005	DBLP DOI BibTeX RDF
14	Gerassimos D. Barlas	VoD on steroids: Optimized content delivery using distributed video servers over best-effort Internet.	J. Parallel Distributed Comput.	2005	DBLP DOI BibTeX RDF