F. Moser, A. Kraifi, and W. Klas. L/MRP: A buffer management strategy for interactive continuous data flows in a multimedia DBMS. In Proc. of VLDB Conf., pp. 275--286, Zurich, Switzerland, Sep. 1995.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....this problem, a modified LRU scheme [17] presented in [8] uses two LRU chains: one for prefetched pages and one for referenced pages. The goal of this scheme is to ensure that the prefetched data to be used before replaced. Another LRU variant, L MRP (Least Most Relevant for Presentation) in [13] extends LRU by also considering potential future references in its replacement policy. By looking ahead to retain aging but soon needed data in the buffer, L MRP is able to provide some advantage over the standard LRU technique. The ability to look ahead, however, comes at a cost. As described in ....

....extends LRU by also considering potential future references in its replacement policy. By looking ahead to retain aging but soon needed data in the buffer, L MRP is able to provide some advantage over the standard LRU technique. The ability to look ahead, however, comes at a cost. As described in [13], whenever a playback advances to the next data block in a video file, the degree of preference of each data block in the buffer must be re evaluated. A method [16] trying to maximize the reusability of cached data partitions the buffer into several, say n, sections, where n is derived from the ....

[Article contains additional citation context not shown here]

F. Moser, A. Kraifi, and W. Klas. L/MRP: A buffer management strategy for interactive continuous data flows in a multimedia DBMS. In Proc. of VLDB Conf., pp. 275--286, Zurich, Switzerland, Sep. 1995.

....[5] proposed using two LRU chains: one for prefetched pages and one for referenced pages. The goal of this technique is to ensure that prefetched data are used before they are replaced. Another LRU variant, L MRP (Least Most Relevant for Presentation) was introduced by Moser, Kraifi and Klas [13]. This scheme extends the LRU technique by also considering potential future references in its replacement policy. By looking ahead to retain aging but soon needed data in the buffer, L MRP is able to provide some advantage over the standard LRU technique. The ability to look ahead, however, comes ....

....technique by also considering potential future references in its replacement policy. By looking ahead to retain aging but soon needed data in the buffer, L MRP is able to provide some advantage over the standard LRU technique. The ability to look ahead, however, comes at a cost. As described in [13], whenever a playback advances to the next data block in a video file, the degree of preference of each data block cached in the buffer must be re evaluated. Another scheme proposed by Ozden, Rastogi and Silberschatz [16] is based on the idea that a data item most recently used is the one which ....

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F. Moser, A. Kraifi, and W. Klas. L/MRP: A buffer management strategy for interactive continuous data flows in a multimedia DBMS. In Proc. of Int'l Conf. on Very Large Databases, pages 275--286, Zurich, Switzerland, September 1995.

....(CLF) DataBlade since the Video Foundation DataBlade does not efficiently support continuous presentation of timedependent media. The main concepts of the CLF DataBlade are a generic data type, called CLF, a client buffer mechanism enabling continuous presentation with respect to VCR interactions [12], and a buffer triggered adaptation method to dynamically adapt to short term bottlenecks at high system load [8] This extension provides the basic functionality needed for interaction with MM data. Browsing, however, requires more structured interaction possibilities, based on vague user ....

....(that is the current buffer unit to be presented) in presentation direction have the highest value, decreasing with the distance from the presentation point. These presentation relevance values a normalisation guarantees that they range between 0 and 1 refer to the currently presented frame [12]. However, jumps to shots of other videos as needed for the browsing application are not considered by presentation values. Furthermore, a more or less rationalist user will select hits more relevant to the content of her previous query with higher probability. Therefore, we use the results of ....

F. Moser, A. Kraiss, and W. Klas. L/MRP: a buffer management strategy for interactive continuous data flows in a Multimedia DBMS. In VLDB, 1995.

....This is especially in distributed environments a formidable task. Although many approaches for server side buffering of multimedia data aiming to share data among multiple users exist ( NY97] RZ95] KRT95] DS96] AWY96] only few mechanism for client side buffering have been proposed ( MKK95] HGP98] MA97] all lacking satisfying solutions for the browsing requirements. For buffering purpose, we segment a video into single parts, in the following called buffer units since it is not possible to preload and replace videos into the buffer as a whole. Each buffer unit represents a ....

....belongs to the Continuous Long Field (CLF) DataBlade that is an integral component of our browsing system architecture. The values of buffer units represent both presentational and retrieval aspects. Presentation values consider the current presentation state and likely VCR interactions [MKK95] For example, the buffer units following the presentation point (that is the current presentation position) in presentation direction have the highest value, decreasing with the distance from the presentation point. The presentation values pv(buffer unit) are used by the buffer management ....

F. Moser, A. Kraiss, and W. Klas. L/MRP: a buffer management strategy for interactivecontinuous data flows in a multimedia dbms. In Proc. Int. Conf. of Very Large Data Bases (VLDB), pages 275--286, September 1995.

....2.2 BUFFER MECHANISM An intelligent buffering mechanism for continuous media streams not only has to optimize access to physical storage it also has to take into account the presentational requirements of the media stream. We use an algorithm called Least Most Relevant for Presentation (L MRP) [MKK95] for preloading and replacing of COPUs in the client buffer. Its goal is to support a synchronized presentation of the media stream. The algorithm considers the current presentation state and likely interactions when deciding which COPUs need to be preloaded and replaced in the client buffer. For ....

Moser F., Kraiss A. and Klas W.: L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proc. Int. Conf. of Very Large Data Bases 1995 (VLDB), Sept. 1995, pages 275-286.

....since user interactions are reflected by modified client requests. We offer generic access and delivery methods for multimedia objects by means of the concept of Continuous Long Fields, a generic data type for timedependent media ( 17] Furthermore, we developed client side caching mechanism [21] and adaptive stream control [16] and integrated these concepts within a commercial object relational DBMS [18] Admission control for interactive applications in client pull is provided to restrict the limited resouces on the server (cf [15] 14] Since browsing applications require conceptual ....

....of relevance values to video shots we consider both, the presentational aspects of the time dependent media to support continuous, jitter and latency free playout and the contentbased retrieval aspects. Presentation values consider the current presentation state and likely VCR interactions [21]. For example, the video shots following the presentation point (i.e. the current shot to be presented) in presentation direction have the highest value, decreasing with the distance from the presentation point. If, for example, achange of the presentation direction is likely in the application, ....

F. Moser, A. Kraiss, and W. Klas. L/MRP: a buffer management strategy for interactivecontinuous data flows in a Multimedia DBMS. In Proc. of the Int. Conf. on Very Large Data Bases (VLDB), pages 275-- 286, Sept 1995.

....presentation of a single media with respect to VCR interactions, like fast forward, fast rewind, or slow motion. So called presentation relevance values are assigned to buffer units representing their relative pertinence to the current presentation state considering likely VCR interactions [31]. Our buffer management algorithm preloads and replaces single objects with respect to their presentation relevance value assuming that a user selects those shots with the highest value. Buffer triggered Adaptation. Our session based admission control mechanism gives no deterministic service ....

....buffer, assuming a buffer size of 20 to 30 MB, i.e. the capacity to buffer 2 to 3 minutes of MPEG 1 video data. Although many approaches for server side buffering of multimedia data aiming to share data among multiple users exist, only few mechanisms for client side buffering have been proposed ([31], 16] 30] 3] all lacking satisfying solutions for the browsing requirements. The L MRP approach, as described in Section 3.1, targets the presentation of one video. But an efficient strategy for video browsing has to buffer parts of various media at the same time to enable fast media ....

F. Moser, A. Kraiss, and W. Klas. L/MRP: a buffer management strategy for interactive continuous data flows in a Multimedia DBMS. In VLDB, 1995.

....(L MRP) for preloading and replacing of video objects in the client buffer. Its goal is to support a continuous presentation of a media stream with respect to VCR interactions. The client buffer manager prefetches data by means of requesting single units of a continuous medium from the server [MKK95] Buffer triggered Adaptation. Our session based admission control mechanism gives no deterministic service guarantees. In case of high system load, bottlenecks may occur during a browsing session. Therefore, we use a client based adaptation mechanism to dynamically adapt to short term ....

....Especially in distributed environments this is a formidable task. Although many approaches for server side buffering of multimedia data aiming to share data among multiple users exist ( NY97] RZ95] KRT95] DS96] AWY96] only few mechanisms for client side buffering have been proposed ( MKK95] HGP98] MA97] ACS98] all lacking satisfying solutions for the browsing requirements. For buffering purposes, we segment videos into single parts, called buffer units in the following. Each buffer unit represents a logical unit of a video instance, e.g. a Group of Pictures of an MPEG ....

[Article contains additional citation context not shown here]

Frank Moser, Achim Kraiss, and Wolfgang Klas. L/MRP: a buffer management strategy for interactive continuous data flows in a multimedia dbms. In Proc. Int. Conf. of Very Large Data Bases (VLDB), pages 275--286, Sept 1995.

....to view a video stream. One example is visual arts students who have to investigate video materials as part of their education. To support such high user interactions without latency or a new data transmission request to the server, the system must be able to buffer certain amount of data [7, 12]. In current design discussed in the literature [4, 6] fast forward and backward functionalities cannot be supported without waiting for the re transmission of the data from the server. In this paper, we will develop a new service to support optimally ensured user interactions with minimum ....

Frank Moser, Achim Kraib, and Wolfgang Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flow in a Multimedia DBMS. In Proceedings of the 21th VLDB conference, pages 275--286, Zurich, Swizerland, 1995.

....Client buffer consumer Presentation Feedback Figure 2. Server and client buffers. 3.2. Bounds on Buffer Levels Research on minimum buffering requirements that are necessary to guarantee the continuity and synchrony of the presentation of multimedia data has been conducted in various papers [2, 5, 10, 20, 13]. Following these results, an acceptable buffer size and buffer prefetching strategies can be designed. We assume that a buffer size has been reasonably assigned. To prevent the buffer overflow underflow, we introduce three water marks for each buffer as the thresholds for initiating feedbacks. ....

Frank Moser, Achim Kraib, and Wolfgang Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flow in a Multimedia DBMS. In Proceedings of the 21th VLDB conference, pages 275-- 286, Zurich, Swizerland, 1995.

....visual arts students who have to investigate video materials as part of their education. To support such high user interactions without latency or a new data transmission request to the server, the system must come up with an efficient scheme to buffer the required amount of data. Current designs [20, 34] only focus on regular playback without interactivity support. 1.2 Related Work There has been increasing interest in flexibly constructing and manipulating heterogeneous presentations from multimedia data resources [23, 4] to support sophisticated applications [36, 16, 1, 11] Research has ....

Frank Moser, Achim Kraib, and Wolfgang Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flow in a Multimedia DBMS. In Proceedings of the 21th VLDB conference, pages 275--286, Zurich, Swizerland, 1995.

....of single continuous media elements, i.e. adapting smoothing the data rate. For the adaptation of video, we find, e.g. approaches that drop single frames [8] MJPEG, MPEG) allow for dropping enhanced layers of MPEG 2 (e.g. 13] skip group of pictures [7] or assign priorities to frames [6, 12]. Some approaches try to adapt not only in one quality dimension but also in two or more, e.g. 15] 14] presents an overall adaptation scheme for handling multiple presentations in multimedia databases but also restricts adaptation to the quality of single media streams. All these techniques ....

F. Moser, A. Krai, and W. Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a MultimediaDBMS. In Proc. VLDB 1995, USA, 1995. Morgan Kaufmann.

....is reexecuted, the saved access trees are compared against the current access tree of the activity, and if a similarity is found, the stored tree is used to preload files. Obviously, knowledge (or estimations) about application behavior might be used for both replacement and prefetching. In [Moser et al. 95] the buffer replacement and preloading strategy least most relevant for presentation designed for interactive continuous data streams is presented. A multimedia object is replaced and prefetched according to its relevance value computed according to the presentation point modus of the data ....

Moser, F., Kraiss, A., Klas, W.: L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS, Proc. of 21 st IEEE Int. Conf. on Very Large Databases (VLDB'95), Zurich, Switzerland, 1995, pp. 275-286

....the disk bandwidth has been studied intensively [6, 32, 36] Closely related to disk allocation and disk scheduling is how to utilize the available main memory for buffer. Several strategies and algorithms are proposed like BASIC and DISTANCE [29] and Least Most Relevant for Presentation (L MRP) [26]. Video delivery across a network has been studied by many researches due to the problem with jitter in networks and the high bandwidth needed for video delivery [5, 34] As a result of this research, new video services like Vosaic [7] Xing s StreamWorks [35] and CNN NEWSROOM [9] are starting to ....

F. Moser, A. Kraiß, and W. Klas. L/MRP: A buffer management strategy for interactive continuous data flows in a multimedia DBMS. In Proceedings of the 21st VLDB Conference, pages 275--286, Zurich, Switzerland, September 1995.

....of service parameters (to support continuous data delivery) and of adaptation schemes (e.g. changing resolution) have to be provided by the application programmer. We have developed a strategy for loading and replacement of continuous objects called Least Most Relevant for Presentation (L MRP) [MKK95]. The strategy supports user interactions like changing direction of playout or speed or jumping to a predefined temporal point. Despite specific buffer strategies, there is no guarantee of continuity for time dependent data streams at times of high system load. Techniques become even more ....

F. Moser, A. Krai, and W. Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proc. Int. Conf. of Very Large Data Bases 1995 (VLDB), pages 275--286, Sep. 1995.

....data, to use efficient media specific database operations, and to efficiently store and retrieve time dependent data. Approaches which extend conventional database system technology try to overcome these limitations. Such extensions, for example, address continuous data management (e.g. [4]) modeling primitives for the handling of continuous data (e.g. 2] that is, built in data types, constructors of temporal composition of continuous data, description of the content of multimedia data, etc. and synchronization support. These extensions mainly focus on the internal database ....

Frank Moser, Achim Kraiss, and Wolfgang Klas. L/MRP: A buffer management strategy for interactive continuous data flows in a multimedia DBMS. To appear in: Procceedings of the 1995 International Conference on Very Large Databases (VLDB), USA, Morgan Kaufmann, 1995.

.... retrieval of multimedia information within the DBMS [SK98] Another challenging issue in this context is to provide techniques for continuous media data delivery and presentation services integrated into a database system in order to achieve really multimedia capable database system support [BKL96,MKK95] Background for this work is the project Gallery of Cardiac Surgery (CardioOP) 1 which aims at the development of a network based and database driven multimedia information system for physicians, medical lecturers, students, and patients in the domain of cardiac surgery. The overall goal is ....

....instance, AMOS features a new multimedia data type for audio, integrated in the underlying OODBMS VODAK, so that it is a built in multimedia data type that can be used in the system s DML like any other simple data type. It also supports continuous media data delivery integrated with the MMDBMS [MKK95] As we were involved in the development of the AMOS system which offers comprehensive support for multimedia, we know that it remains a research prototype though. An OODBMS called Jasmine which features built in multimedia data types has been released by Computer Associates recently. Jasmine ....

[Article contains additional citation context not shown here]

F. Moser, A. Krai, and W. Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proceedings VLDB 1995. Morgan Kaufmann, USA, 1995.

....data, cannot be entirely loaded into the buffer. These objects are therefore decomposed in single small blocks (e.g. audio sequences, frames) which are loaded and replaced in the buffer. Loading and replacement of objects is done by a strategy, called Least Most Relevant for Presentation (L MRP) [5]. The strategy supports user interactions like changing playout direction or speed or jumping to a predefined point. Preloading of blocks is done asynchronously and for those blocks which seem to be most important at the actual presentation state. Single blocks get relevance values which reflect ....

F. Moser, A. Kraiß, and W. Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proc. Int. Conf. of Very Large Data Bases 1995 (VLDB), pages 275--286, Sep. 1995.

.... as well as across sessions (consisting of a bundle of streams) Previously, we have described an architecture for a database service for RPM [27, 28] a heuristic method to optimize adaptations of an arbitrary presentational session [26] an adaptive buffer management strategy for continuous data [17], and a general framework for adaptive methods for multimedia systems [8] The new work presented in this paper is the distributed load control scheme PYLOT Scheme (PlaYout Load OpTimization) for RPM in systems with best effort data delivery. Moreover, we propose an allocation routine for shares ....

....solution we handle this trade off by modelling the allocation task as linear program which optimizes total adjustment costs and total adjustment profit, respectively. Currently, we are integrating a RPM service in GMD IPSI s distributed multimedia database system AMOS (Active Media Object Stores) [1, 17, 26, 27], a research prototype based on IPSI s object oriented database management system VODAK [10] Thereby, the PYLOT Scheme and the allocation method will be used. Within OGI s project QUASAR (QUAlity Specification and Adaptive Resource management for distributed multimedia systems) 5, 6, 8, 23] a ....

[Article contains additional citation context not shown here]

F. Moser, A. Kraiss, and W. Klas. L/mrp: A buffer management strategy for interactive continuous data flows in a multimedia database management system. In Proc. of the VLDB '95, pages 275--286, Zurich, Switzerland, September 1995.

....and describe how they must work together to achieve PB RPM. This proposal is an extention of our general concept of Playout Management in distributed MM DBS [12] that we have realized within the context of IPSI s AMOS system. The AMOS system is a research prototype of a distributed MM DBMS [12, 8, 14]. The development of AMOS is driven by experiences gathered by several concrete multimedia applications, e.g. 16, 15] The remainder of this paper is organized as follows. Section 2 introduces PB RPM independent of a concrete type of system. Section 3 discusses the specific requirements for ....

....A model for PB RPM with presentation quality based control dia data from external storage devices over a network into a bounded buffer at the presentation site. The current throughput of this process is denoted by T . It is the objective of this process to maintain a so called buffer safety level [8] denoted by S. S is that amount of buffered data necessary for the n next presentation seconds relative to the current presentation time. The current presentation quality that the prefetch process supports is denoted by Q b . The current buffer level is denoted by B. An asynchronously running ....

F. Moser, A. Kraiss, and W. Klas. L/mrp: A buffer management strategy for interactive continuous data flows in a multimedia database management system. In Proc. of the VLDB '95, Zurich, Switzerland, Sept. 1995.

.... database system in the future, following the approach taken in (Bohm et al. 1997) Furthermore, we are working on a generic presentation engine for Z Y X documents which includes support for continuous MPEG video streams based on an extension of the L MRP buffer management technique (Moser et al. 1995). Further work is needed to extend the representation of meta data, its usage for querying the Cardio OP repository taking into account the various approaches discussed in, e.g. Sheth and Klas, 1998) and to exploit appropriate indexing techniques. Acknowledgments We would like to thank Utz ....

Moser, F., Kraiß, A., and Klas, W. (1995). L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proceedings VLDB 1995, USA. Morgan Kaufmann.

....programming interface for Continuous Long Fields includes requests with the number and the quality of COPUs. We use the proposed adaptation technique in combination with an algorithm called Least Most Relevant for Presentation (L MRP) algorithm for loading and replacement of COPUs in the buffer [MKK95]. The algorithm supports continuous access to COPUs by keeping those COPUs in the buffer that are determined to be relevant for the actual presentation state. The relevance values are computed from assumed possibilities of user interactions for the actual state, e.g. a change in playout direction ....

Frank Moser, Achim Kraiss and Wolfgang Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proc. Int. Conf. of Very Large Data Bases 1995 (VLDB), pages 275--286, Sept. 1995.

....(COPU) A Continuous Long Field consists of a sequence of COPUs. Furthermore, metadata like format and recording parameters are stored with every field. Preloading and replacement of COPUs in the client buffer is managed by using an algorithm called Least Most Relevant for Presentation (L MRP) [MKK95]. The algorithm does not only preload those COPUs needed for a continuous presentation of a Continuous Long Field but also considers the current presentation state and likely interactions when deciding which COPU should be replaced from buffer. 3 The Adaptation Framework In the following, we ....

Frank Moser, Achim Kraiss and Wolfgang Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proc. Int. Conf. of Very Large Data Bases 1995 (VLDB), pages 275--286, Sept. 1995.

.... has been studied mostly for applications where future access patterns are largely predictable due to specific structures of the underlying databases and the programs accessing them, especially in objectoriented database systems [CK89, CH91, GK94] but also in real time and multimedia applications [WZ86, MKK95, TP97]. The effect of object prefetching is implicitly achieved (on a per page basis) also by intelligently clustering objects into pages [CK89, TN91, TN92, GKKM93] In the field of mobile computing, KP97] has pursued a similar approach where reference distances in user and program access patterns ....

....side, PZ91] has proposed an associative memory approach for predicting object requests and initiating prefetching. A major disadvantage of this approach is that the associative memory needs offline training, which renders it infeasible for document archives with evolving workload patterns. [MKK95] has proposed a relevance ranking scheme for the buffering of video frames in multimedia applications that aims to capture access probabilities, but relies on external input for determining the relevance measures. In [CKV93] compression schemes based on k th order Markov chains have been ....

Moser F, Kraiss A, Klas W (1995) L/MRP -- A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In: VLDB Conf., 1995, Zurich, Switzerland, pp 275--286

....data, unlike discrete data, cannot be entirely loaded into the buffer. These objects are therefore decomposed into small blocks (e.g. audio sequences, video frames) which are preloaded and replaced into the buffer by a clever buffer management strategy, called Least Most Relevant for Presentation [MKK95]. We call our generic data type Continuous Long Fields. A continuous long field is quite similar to a binary large object (BLOB) but specifications of quality of service parameters to support continuous data delivery and of adaptation schemes, e.g. lower resolution, can be provided to the ....

....be used as stand alone solutions. Rather, they become more useful in combination with other approaches on network side and server side. We use the proposed adaptation technique in combination with the Least Most Relevant for Presentation (L MRP) algorithm for the buffer loading and replacement [MKK95]. This algorithm supports continuous access to CODUs by keeping COPUs in the buffer which are determined to be relevant for the actual presentation state. The most important COPUs are preloaded asynchronously by evaluating relevance values that consider the possibility of user interactions for the ....

F. Moser, A. Kraiß and W. Klas. L/MRP: A Buffer Management Strategy for Interactive Continuous Data Flows in a Multimedia DBMS. In Proc. Int. Conf. of Very Large Data Bases 1995 (VLDB), pages 275--286, Sept. 1995.

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