Browsing by Author "Chang, YI"

Now showing 1 - 6 of 6

A new storage and retrieval method to support editing operations in a multi-disk-based video server
(1996)
Lee, CI
;
Chang, YI
;
Yang, WP
;
交大名義發表
;
資訊工程學系
Since the storage ordering is assumed the same ns the retrieval ordering in all the previous storage placement strategies, there is a requirement of a large amount of file copying or merging operations when users insert/delete some data into/from the media data. The observation is also important for video applications because features, like video editing, require the support of random access on individual video frames. fn this paper, roe propose a new strategy for the insert/delete operations on continuous media that are striped into multi- disks without reorganization of the whole data. From our performance analysis and simulation, the proposed algorithms for insertion/deletion may require only some additional movement cost.
Alternating hashing for expansible files
(1997-01-01)
Chang, YI
;
Lee, CI
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a generalized approach for designing a class of dynamic hashing schemes which require no index and have the growth of a file at a rate of n+1/n per full expansion, where n is the number of pages of the file, as compared to a rate of two in linear hashing. Based on this generalized approach, we derive a new dynamic hashing scheme called alternating hashing, in which, when a split occurs in page k, the data records in page k will be redistributed to page k and page (k + 1), or page k and page (k - 1), according to whether the value of level dis even or odd, respectively. (Note that a level is defined as the number of full expansions happened so far.) From our performance analysis, given a fixed load control, the proposed scheme can achieve nearly 97% storage utilization as compared to 78% storage utilization by using linear hashing.
Alternating hashing for expansible files
(1997-01-01)
Chang, YI
;
Lee, CI
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a generalized approach for designing a class of dynamic hashing schemes which require no index and have the growth of a file at a rate of n+1/n per full expansion, where n is the number of pages of the file, as compared to a rate of two in linear hashing. Based on this generalized approach, we derive a new dynamic hashing scheme called alternating hashing, in which, when a split occurs in page k, the data records in page k will be redistributed to page k and page (k + 1), or page k and page (k - 1), according to whether the value of level dis even or odd, respectively. (Note that a level is defined as the number of full expansions happened so far.) From our performance analysis, given a fixed load control, the proposed scheme can achieve nearly 97% storage utilization as compared to 78% storage utilization by using linear hashing.
An efficient conflict-resolution approach to support read/write operations in a video server
(1997-09-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient conflict-resolution approach based on the multi-disk architecture for the insertion/deletion operations on continuous media that are split up into blocks and placed in various locations on the disk, without reorganizing the whole data. When a new subobject is inserted after subobject i, it will be assigned with an identification number (i+1) and be inserted into a disk in which the retrieval of the new subobject does not conflict with the retrieval of any other subobject, where a conflict means a pair of two consecutive subobjects that are stored in the same disk have to be retrieved simultaneously However, a new conflict on the same disk may occur since all the identification numbers of subobjects after subobject i are increased by one. Only when such a new conflict occurs, one movement operation is required, so does the case of a deletion operation. Moreover, to reduce those additional movement cost, a deferring approach is proposed at the cost of an additional buffer. In this approach, n data insertions are deferred and stored in a buffer. Then, the system starts to insert those data after an optimal insertion sequence is determined. Based on this approach, two strategies are proposed: the conflict-resolved-first-deferring strategy (the CRFD strategy) and the conflict-resolved-last-deferring strategy (the CRLD strategy). From our performance analysis, we will prove that the CRLD strategy with an insertion sequence according to the ascending order of identification numbers is an optimal strategy based on the proposed deferring approach.
An efficient conflict-resolution approach to support read/write operations in a video server
(1997-09-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient conflict-resolution approach based on the multi-disk architecture for the insertion/deletion operations on continuous media that are split up into blocks and placed in various locations on the disk, without reorganizing the whole data. When a new subobject is inserted after subobject i, it will be assigned with an identification number (i+1) and be inserted into a disk in which the retrieval of the new subobject does not conflict with the retrieval of any other subobject, where a conflict means a pair of two consecutive subobjects that are stored in the same disk have to be retrieved simultaneously However, a new conflict on the same disk may occur since all the identification numbers of subobjects after subobject i are increased by one. Only when such a new conflict occurs, one movement operation is required, so does the case of a deletion operation. Moreover, to reduce those additional movement cost, a deferring approach is proposed at the cost of an additional buffer. In this approach, n data insertions are deferred and stored in a buffer. Then, the system starts to insert those data after an optimal insertion sequence is determined. Based on this approach, two strategies are proposed: the conflict-resolved-first-deferring strategy (the CRFD strategy) and the conflict-resolved-last-deferring strategy (the CRLD strategy). From our performance analysis, we will prove that the CRLD strategy with an insertion sequence according to the ascending order of identification numbers is an optimal strategy based on the proposed deferring approach.
Design of a new indexing organization for a class-aggregation hierarchy in object-oriented databases
(1999-03-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In an object-oriented database, a class consists of a set of attributes, and the values of the attributes are objects that belong to other classes; that is, the definition of a class forms a class-aggregation hierarchy of classes. A branch of such a hierarchy is called a path. Several index organizations have been proposed to support object-oriented query languages, including multiindex, join index, nested index and path index. All the proposed index organizations are helpful only for a query which retrieves the objects of the root class of a given path using a predicate which specifies the value of the attribute at the end of the path. In this paper, we propose a new index organization for evaluating queries, called full index, where an index is allocated for each class and its attribute (or nested attribute) along the path. From the analysis results, we show that a full index can support any type of query along a given path with a lower retrieval cost than all the other index organizations. Moreover, to reduce the high update cost for a long given path, we split the path into several subpaths and allocate a separate index to each subpath. Given a path, the number of subpaths and the index organization of each subpath define an index configuration. Since a low retrieval cost and a low update cost are always a trade-off in index organizations, we also propose cost formulas to determine the index configuration which can provide the best performance for various applications by taking into account various types of queries along a given path and a set of queries with more than one nested predicate along a given path.