• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.87-94
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• 2003

As the number of the Internet users increases explosively, a solution for this problem is web caching. So, many techniques on improving cache server performance have been suggested. In this paper, we analyze the cause of the bottleneck in cache servers, and propose an arbitral thread and delayed caching mechanism as a solution. We use an arbitral thread in order to provide a quick service to user requests through eliminating the ready multi-thread search problem in case of disk writing operation. We also use delayed caching in order to provide stable system operation through avoiding overloaded disk operation and queue threshold. Proposed cache server is implemented through modification on SQUlD cache server, and we compare its performance with the original SQUID cache server.

• Journal of Communications and Networks
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• v.12 no.1
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• pp.52-66
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• 2010

Since large objects consume substantial resources, web proxy caching incurs a fundamental trade-off between performance (i.e., hit-ratio and latency) and overhead (i.e., resource usage), in terms of caching and relaying large objects to users. This paper investigates how and to what extent the current dedicated-server based web proxy caching scheme is affected by large file transfers in a high bandwidth campus network environment. We use a series of trace-based performance analyses and profiling of various resource components in our experimental squid proxy cache server. Large file transfers often overwhelm our cache server. This causes a bottleneck in a web network, by saturating the network bandwidth of the cache server. Due to the requests for large objects, response times required for delivery of concurrently requested small objects increase, by a factor as high as a few million, in the worst cases. We argue that this cache bandwidth bottleneck problem is due to the fundamental limitations of the current centralized web proxy caching model that scales poorly when there are a limited amount of dedicated resources. This is a serious threat to the viability of the current web proxy caching model, particularly in a high bandwidth access network, since it leads to sporadic disconnections of the downstream access network from the global web network. We propose a peer-to-peer cooperative web caching scheme to address the cache bandwidth bottleneck problem. We show that it performs the task of caching and delivery of large objects in an efficient and cost-effective manner, without generating significant overheads for participating peers.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.29-36
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• 2004

As the number of Internet users and the amount of web contents have increased very fast, reducing the load of web servers and providing web services more rapidly have been great issues. A web-cache system, which is located between the user and the web server, has been used by many web service providers as an effective way to reduce the load of web servers and the web service response time. In this paper, we have developed a web-cache system which is based on the Squid cache and has a compression capability. The web-cache system in which compression capability reduces the amount of network traffic and the web service response time by transfering the web contents in the compressed format over the network between the web-cache system and the user. The performance enhancement is greater in the reverse-cache system than in the forward-cache system because in the case of the reverse-cache system, the cache reduces the amount of traffic on the Internet which is the bottleneck in the network path between the user and the web server. The experimentation result shows that the amount of data traffic has reduced from 2 to 8 times depending on the size of the web contents. The web server response time has reduced 37% on the average and when the size of the web content is greater than 10Kbyte, the response time has reduced 87% on the average.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.382-384
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• 2001

인터넷 사용자의 증가로 인한 서버의 과부하 및 네트워크 응답시간 지연의 대안으로 캐시서버의 사용이 보편화되고 있다. 그러 나, 최근 유해사이트의 급격한 중가로 캐시 서버의 부가 기능인 ACL(Access Control List)또한 중요한 기능의 하나가 되면서 대량의 유해사이트 차단 목록이 캐시 서버의 병목현상을 가중시키고 있다 본 논문에서는 캐시 서버의 대명사격인 Squid의 ACL방식과 대량의 black list를 적용했을 때의 ACL의 regular expression방식의 문제점을 살펴보고, 대량의 black list에 적합한 hash기반 ACL 처리 방식을 제안한다. hash를 이용한 ACL방식은 빠른 검색을 제공하여 캐시 서버의 응답시간에 큰 영향을 주지않기 때문에 캐시서버가 정상적인 서비스를 할 수 있도록 해준다.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.603-608
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• 2005

Disk I/O is a major performance bottleneck of web proxy server. Today's most web proxy sowers are design to run on top of a general purpose file system. But general purpose file system can not efficiently handle web cache workload, small files, leading to the performance degradation of entire web proxy servers. In this paper we evaluate the performance potential of raw disk to reduce disk I/O overhead of web proxy servers. To show the performance potential of raw disk, we design a storage management system called Block-structured Storage Management System (BSMS). And we also actually implement web proxy server that incorporate BSMS in Squid. Comprehensive experimental evaluations show that raw disk can be a good solution to improve disk I/O performance significantly for web proxy servers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.344-354
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• 2013

In this paper, In order to solve the traffic of the SNS to be executed on smartphone, we propose the design of the SNS integrated gateway server. Also, we capture the payload size in a variety of methods to send the MQTT protocol and QoS level of MQTT protocol for communication between the client and the Gateway. And we present the results and analysis of packet loss and end-to-end delay. By using analysis proposed, we present the results of the integrated SNS Gateway push notification protocol design.