• Journal of KIISE:Computer Systems and Theory
• /
• v.30 no.7_8
• /
• pp.426-433
• /
• 2003

Management policies of Web Proxy Cache, for the QoS of Web users, are mainly focused on the page replacement and the data consistency policy. But the two subjects have been studied independently to each other regardless of its possibility of cooperation. In this paper, we introduce the performance improvement obtained by adapting the characteristic of LMF used in data consistency policy to LRU, thus taking the better performance synergy as a result of complementary cooperation. Various policies for the management of Web Proxy Cache are in progress, this study can be a way of performance guide to increase cache hit ratio and reduce the transmission overhead of Web Server.

• The KIPS Transactions:PartD
• /
• v.14D no.4 s.114
• /
• pp.447-458
• /
• 2007

The objective of this study is to provide faster mobile web service by improving performance of Contents Cache used for mobile web service in the existing Mobile Gate System. It was found that two elements existed in Mark-Up page transcoded by Contents Generator. One of the elements was dependent only on the requested DIDL page and Mark-Up type. The other was dependent on each of the requested DIDL page, Mark-Up type, size of mobile display 모바일 장치 to request service, type of images available and color depth count of the images available. The conventional Contents Cache saved the entire Mark-Up page to hold both of the two elements. This caused the problem where storage space was not effectively used because reusable elements were repetitively saved in cache memory domain due to change in one of the elements even though all the other elements were the same. As a result, a larger number of transcoded Mark-Up pages could not be saved in the same cache memory size. Therefore, in this study, Mark-Up pages transcoded by Contents Generator were divided into two elements and were separately saved. Also, in order to respond to the demand for replacing data in cache with new data, this study applied two algorithms of LFU and LRU. This study proposed the method to implement cache performance of faster speed by enabling to save more number of the transcoded Mark-Up pages in the same cache storage space.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.6
• /
• pp.346-353
• /
• 2002

The explosive increase of World Wide Web usage has incurred significant amount of network traffic and server load. To overcome these problems, web proxy caching replicates frequently requested documents in the web proxy closer to the users. Cache utilization depends on the replacement policy which tries to store frequently requested documents in near future. Temporal locality and Zipf frequency distribution, which are commonly observed in web proxy workloads, are considered as the important properties to predict the popularity of documents. In this paper, we propose a novel cache replacement policy, called Adaptive LFU (ALFU), which incorporates 1) Zipf frequency distribution by utilizing LFU and 2) temporal locality adaptively by measuring the amount of the popularity reduction of documents as time passed efficiently. We evaluate the performance of ALFU by comparing it to other policies via trace-driven simulation. Experimental results show that ALFU outperforms other policies.

• Proceedings of the IEEK Conference
• /
• 2002.06c
• /
• pp.153-156
• /
• 2002

As the use of world wide web is increasing, the number of connections to servers is increasing also. These interactions increase the load of networks and servers. therefore efficient caching strategies for web documents are needed to reduce server load and network traffics by migrating copies of server files closer to the clients that use those files. As One idea of caching policy, we propose a Weighted Disk Cache Replacement Policy(WDCRP) which analyses user's interaction to WWW and adds weight value to each web document. Especially the WDCRP takes account of the history data of cache log, the characteristics of Web requests and the importance of user interactive-actions.

• Journal of the Korea Society for Simulation
• /
• v.12 no.2
• /
• pp.25-34
• /
• 2003

Because of explosive growth in demand for web-based multimedia applications, proper proxy caching for large multimedia object (especially video) has become needed. For a video object which is much larger in size and has different access characteristics than the traditional web object such as image and text, caching the whole video file as a single web object is not efficient for the proxy cache. In this paper, we propose a proxy caching strategy with the constant-sized segment for video file and an improved proxy cache replacement policy. Through the event-driven simulation under various conditions, we show that our proposal is more efficient than the variable-sized segment strategy which has been proven to have higher hit ratio than other traditional proxy cache strategies.

• The KIPS Transactions:PartC
• /
• v.9C no.6
• /
• pp.961-968
• /
• 2002

This paper proposes a new access method which is to considered the high variability in World Wide Web and manage the web cache space. Instead of using a single cache, we divide a cache and store all documents according to their file types. Proposed method was compares with current cache management policies using LFU, LRU and SIZE base algorithm. Using two different workload, we show the improvement hitting ratio and byte hitting ratio through simulating on the file type caching.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1084-1089
• /
• 2004

This paper describes the improvement of web cache server by scoping in replacement algorithm of data which are collected from the clients. We have found that each replacement algorithm is suitable for each type of data in the web pages. Therefore, we introduce the mechanism to select the replacement algorithm depending on the size of data called the Replacement Algorithm Selection Mechanism (RASM). RASM allows the web cache server to have the suitable replacement algorithm for each type of data. As the result, the byte hit ratio of web cache server can be increased and the congestion in the network can be alleviated.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.5C
• /
• pp.399-410
• /
• 2002

Web cache, which is functionally another word of proxy server, is located between client and server. Web cache has a limited storage area although it has broad bandwidth between client and proxy server, which are usually connected through LAN. Because of limited storage capacity, existing objects in web cache can be deleted for new objects by some rules called replacement algorithm. Hit rate and byte-hit rate are general metrics to evaluate replacement algorithms. Most of the replacement algorithms do satisfy only one metric, or sometimes none of them. In this paper, we propose two replacement algorithms to achieve both high hit rate and byte-hit rate with great satisfaction. In the first algorithm, the cache is appropriately partitioned according to file types as a basic model. In the second algorithm, the cache is composed of two levels; the upper level cache is managed by the basic algorithm, but the lower level is collectively used for all types of files as a shared area. To show the performance of the proposed algorithms, we evaluate hit rate and byte-hit rate of the proposed replacement algorithms using the trace driven simulation.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.7
• /
• pp.2161-2168
• /
• 2000

Since most of the existing web cache structures are static, they cannot support the dynamic request change of he current WWW users well. Users re generally using multiple programs in several different windows with rapid preference change within a relatively short period of time. We develop a network-path based algorithm. It organizes a cache according to the network path of the requested URLs and build a network cache farm where caches are logically connected with each other and each cache has its own preference over certain network paths. The algorithm has been implemented and tested in a real site. The performance results show that the new algorithm outperforms the existing static algorithms in the hit ratio and response time dramatically.

• Journal of Communications and Networks
• /
• v.8 no.3
• /
• pp.330-338
• /
• 2006

Many web cache systems and policies concerning them have been proposed. These studies, however, consider large objects less useful than small objects in terms of performance, and evict them as soon as possible. Even if this approach increases the hit rate, the byte hit rate decreases and the connections occurring over congested links to outside networks waste more bandwidth in obtaining large objects. This paper puts forth a client-cluster approach for improving the web cache system. The client-cluster is composed of the residual resources of clients and utilizes them as exclusive storage for large objects. This proposed system achieves not only a high hit rate but also a high byte hit rate, while reducing outgoing traffic. The distributed hash table (DHT) based peer-to-peer lookup protocol is utilized to manage the client-cluster. With the natural characteristics of this protocol, the proposed system with the client-cluster is self-organizing, fault-tolerant, well-balanced, and scalable. Additionally, the large objects are managed with an index based allocation method, which balances the loads of all clients well. The performance of the cache system is examined via a trace driven simulation and an effective enhancement of the proxy cache performance is demonstrated.