Content Delivery Cloud (CDC) extends Content Delivery Network (CDN) to provide elastic, scalable and low cost services to the customers. For multimedia streaming over CDC, caching the media content onto the edge serve...
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ISBN:
(纸本)9781467348638
Content Delivery Cloud (CDC) extends Content Delivery Network (CDN) to provide elastic, scalable and low cost services to the customers. For multimedia streaming over CDC, caching the media content onto the edge server from storage cloud is commonly used to minimize the latency of content delivery. It is very important for CDN to balance between the resources being used (storage space, bandwidth, etc) and the performance achieved. Commercial CDNs (such as Akamai, Limelight, Amazon CloudFront) have their proprietary caching algorithms to deal with this issue. In this paper, we propose a method to further improve the efficiency of the caching system for scalable multimedia contents. Specifically, we notice that a scalable multimedia content can be flexibly truncated to lower bit rates on-the-fly based on the available network bandwidth between the edge server to the end users. Therefore, it may not be necessary to cache such a content at its highest quality/rate. Based on this observation, we show that edge server can decide an optimized truncation ratio for the cached scalable multimedia contents to balance between the quality of the media and the resource usage. The proposed optimized truncation algorithm is analyzed and its efficacy in improving the efficiency of the caching system is justified with simulation result.
Although multi-tiered software development is taking the place in database application environments, client-server infrastructure has still been in use for years. Furthermore, both infrastructures still need to be imp...
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Although multi-tiered software development is taking the place in database application environments, client-server infrastructure has still been in use for years. Furthermore, both infrastructures still need to be improved in some aspects. One of the important aspects of improvement is caching. This paper addresses the issue of caching in relational database system within client-server structure and a method that can be used to keep clients' cache up to date. The main objective of the proposed caching methods is to use clients' idle time in order that clients' cache is up-to-dated and to use the clients' memories for caching. For this purpose, a new combined system which includes CCDT (Clients Cache Description Table) for organizing client cache updating, predicate-based caching method MNTC (Maximum Number of Tuples in Cache) that includes a managerial patch in server-side and small patches in clients-side, and TPCF (Time Period calculated from client Commit Frequency) for calculation of idle time of the clients, is presented.
This paper proposes a DSM-CC carousel caching and management architecture that can support both priority-based scheduling of monitoring threads and caching of carousel objects for a quick launch and download of Xlet. ...
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This paper proposes a DSM-CC carousel caching and management architecture that can support both priority-based scheduling of monitoring threads and caching of carousel objects for a quick launch and download of Xlet. The carousel objects are broadcast cyclically by the transmission policy. Lack of carousel object reception may cause performance deterioration. The data broadcasting middleware should guarantee real-time characteristics such as the processing time in periodic monitoring threads to detect a change in information without a long latency time. Therefore this proposed architecture can improve the predictability of periodic monitoring section filter threads by using the managing the thread pool and scheduling periodic threads. To guarantee fast launch of the data broadcasting application, this paper also proposes the cache control mechanism of DSM-CC data/object carousel. This proposed architecture can accommodate data broadcasting middleware that uses DSM-CC object carousel mechanisms, such as ACAP, OCAP and MHP.
The efficient distribution of stored information has become a major concern ill the Internet. Since the web workload characteristics show that more than 60% of network traffic is caused by image documents. how to effi...
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The efficient distribution of stored information has become a major concern ill the Internet. Since the web workload characteristics show that more than 60% of network traffic is caused by image documents. how to efficiently distribute image documents from servers to end clients is an important issue. Proxy cache is an efficient solution to reduce network traffic. 2 And it has been shown that an image caching method (Graceful caching) based oil hierarchical coding format performs better than conventional caching schemes ill recent years. However, as the capacity of the Cache is limited, how to efficiently allocate the cache memory to achieve a minimum expected delay time is still a problem to he resolved. This paper presents all integrated caching algorithm to deal with the above problem for image databases. web browsers, proxies and other similar applications ill the Internet. By analyzing the web request distribution of the Graceful caching, both replacing and pre-fetching algorithms are proposed. We also show that our proposal can be carried out based oil information readily available ill the proxy server;it flexibly adapts its parameters to the hit rates and access pattern of users requesting documents in the Graceful caching. Finally we verify the performance of this algorithm by simulations.
The efficient distribution of stored information has becomea major concern in the Internet. Since the web workloadcharacteristics shows that more than 60% of network traffic iscaused by image documents, how to efficie...
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The efficient distribution of stored information has becomea major concern in the Internet. Since the web workloadcharacteristics shows that more than 60% of network traffic iscaused by image documents, how to efficiently distributeimage documents from servers to end clients is an importantissue. Proxy cache is an efficient solution to reduce networktraffic. And it has been shown that an image caching method(Graceful caching) based on hierarchical coding formatshowed better performance than conventional cachingschemes in recent years. However, as the capacity of the cacheis limited, how to efficiently allocate the cache memory toachieve a minimum expected delay time is still a problem to beresolved. This paper presents an integrated caching algorithm to dealwith the above problem in the Internet. By analyzing the webrequest distribution of Graceful caching, both replacementand pre-fetching algorithms are proposed. We also show thatour proposal can be carried out based on information readilyavailable in the proxy server and it flexibly adapts itsparameters to the hit rates and access pattern of users'requesting documents in the Graceful caching. we finallyverify the performance of this algorithm by simulations.
Since the traffic of NetNews is increasing, keeping all articles becomes serious problem from a viewpoint of waste of network bandwidth and the amount of disk usage. In addition, users read not all incoming articles. ...
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Since the traffic of NetNews is increasing, keeping all articles becomes serious problem from a viewpoint of waste of network bandwidth and the amount of disk usage. In addition, users read not all incoming articles. We have proposed several caching algorithms to overcome this problem and shown that a selective prefetch scheme gives the best system performance among the proposed ones. However, since the selective prefetch scheme employed a simple selecting policy, the scheme gave low hit ratio in some cases. Therefore, this paper intends to improve the selective prefetch scheme from a viewpoint of the amount of disk usage as well as hit ratio. In this paper, we divide the scheme into three factors: reference span, criterion, and threshold in criterion. Through simulation experiments using actual NetNews logs, we investigate the influence of the factors of the reference span and the threshold to system performance. As a result, it is shown that the reference span is more significant factor than the threshold, the selective prefetch scheme with a value around the seven days reference span keeps high hit ratio and reduces the amount of disk usage.
Since the traffic of NetNews is increasing, storage of all articles becomes a serious problem from the viewpoint of wasting network bandwidth and the amount of disk usage. In addition, not all incoming articles are re...
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