P2P VOD 서비스를 위한 통합 버퍼링 기법

강보아,김은삼 한국차세대컴퓨팅학회 2016 한국차세대컴퓨팅학회 논문지 Vol.12 No.6

본 논문에서는 P2P VOD 시스템에서 푸시 방식의 구간 캐싱 기법과 풀 방식의 메시 구조의 장점을 동시에 활용하 는 통합 버퍼링 기법을 제안한다. 새로운 피어가 참여할 때 해당 피어가 필요한 데이터를 저장하고 있는 선행 피어 가 존재한다면 푸시 방식의 구간 캐싱 기법을 사용하고 그렇지 않을 경우 기존의 메시-풀 방식으로 이웃 피어들로부 터 데이터를 전송 받는다. 구간 캐싱 기법으로 데이터를 전송하고 있던 피어가 이탈하면 다시 새로운 선행 피어를 탐색하고 불가능할 경우에는 메시-풀 방식으로 전송받는다. 따라서 푸시 방식의 구간 캐싱 기법의 우수한 성능을 최 대한 유지하면서 마지막으로 이탈에 안정적인 메시-풀 방식을 사용할 수 있다. 또한 실험을 통해 본 논문에서 제안 하는 통합 버퍼링 기법이 피어들의 평균 도착 간격이 변화하더라도 구간 캐싱과 메시-풀 방식만 사용하는 기법에 비 해 성능이 우수하다는 것을 보인다. In this paper, we propose an integrated buffering scheme to take advantages of both push-based interval caching scheme and pull-based mesh scheme simultaneously. In our paper, when a new peer joins, we adopt the push-based interval caching scheme if there exists any preceding peer that is storing the data required by the new peer. Otherwise it receives the required data from the neighbor peers through the mesh-pull scheme. Whenever the preceding peer using the interval caching leaves the network, the following peer tries to find any possible peer that can serve as a preceding peer. If it fails, it chooses mesh-pull scheme. As a result, we eventually employ the mesh-pull scheme that is stable against peers’ departure while keeping the push-based interval caching’s benefit of the better performance. By simulations, we show that our proposed integrated buffering scheme outperforms the interval caching and mesh-pull schemes even though varying the average inter-arrival times among peers.

Optimizing Caching in a Patch Streaming Multimedia-on-Demand System

Dinkisa Aga Bulti,Kumudha Raimond 한국정보과학회 2015 Journal of Computing Science and Engineering Vol.9 No.3

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

Optimizing Caching in a Patch Streaming Multimedia-on-Demand System

Bulti, Dinkisa Aga,Raimond, Kumudha Korean Institute of Information Scientists and Eng 2015 Journal of Computing Science and Engineering Vol.9 No.3

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

Hierarchical Location Caching Scheme for Mobile Object Tracking in the Internet of Things

Han, Youn-Hee,Lim, Hyun-Kyo,Gil, Joon-Min Korea Information Processing Society 2017 Journal of information processing systems Vol.13 No.5

Mobility arises naturally in the Internet of Things networks, since the location of mobile objects, e.g., mobile agents, mobile software, mobile things, or users with wireless hardware, changes as they move. Tracking their current location is essential to mobile computing. To overcome the scalability problem, hierarchical architectures of location databases have been proposed. When location updates and lookups for mobile objects are localized, these architectures become effective. However, the network signaling costs and the execution number of database operations increase particularly when the scale of the architectures and the numbers of databases becomes large to accommodate a great number of objects. This disadvantage can be alleviated by a location caching scheme which exploits the spatial and temporal locality in location lookup. In this paper, we propose a hierarchical location caching scheme, which acclimates the existing location caching scheme to a hierarchical architecture of location databases. The performance analysis indicates that the adjustment of such thresholds has an impact on cost reduction in the proposed scheme.

Hierarchical Location Caching Scheme for Mobile Object Tracking in the Internet of Things

( Youn-hee Han ),( Hyun-kyo Lim ),( Joon-min Gil ) 한국정보처리학회 2017 Journal of information processing systems Vol.13 No.5

Mobility arises naturally in the Internet of Things networks, since the location of mobile objects, e.g., mobile agents, mobile software, mobile things, or users with wireless hardware, changes as they move. Tracking their current location is essential to mobile computing. To overcome the scalability problem, hierarchical architectures of location databases have been proposed. When location updates and lookups for mobile objects are localized, these architectures become effective. However, the network signaling costs and the execution number of database operations increase particularly when the scale of the architectures and the numbers of databases becomes large to accommodate a great number of objects. This disadvantage can be alleviated by a location caching scheme which exploits the spatial and temporal locality in location lookup. In this paper, we propose a hierarchical location caching scheme, which acclimates the existing location caching scheme to a hierarchical architecture of location databases. The performance analysis indicates that the adjustment of such thresholds has an impact on cost reduction in the proposed scheme.

Hierarchical Location Caching Scheme for Mobile Object Tracking in the Internet of Things

한연희,임현교,길준민 한국정보처리학회 2017 Journal of information processing systems Vol.13 No.5

Mobility arises naturally in the Internet of Things networks, since the location of mobile objects, e.g., mobileagents, mobile software, mobile things, or users with wireless hardware, changes as they move. Tracking theircurrent location is essential to mobile computing. To overcome the scalability problem, hierarchicalarchitectures of location databases have been proposed. When location updates and lookups for mobileobjects are localized, these architectures become effective. However, the network signaling costs and theexecution number of database operations increase particularly when the scale of the architectures and thenumbers of databases becomes large to accommodate a great number of objects. This disadvantage can bealleviated by a location caching scheme which exploits the spatial and temporal locality in location lookup. Inthis paper, we propose a hierarchical location caching scheme, which acclimates the existing location cachingscheme to a hierarchical architecture of location databases. The performance analysis indicates that theadjustment of such thresholds has an impact on cost reduction in the proposed scheme.

이동 컴퓨팅 환경에서 방송기반의 낙관적 캐쉬 프로토콜들에 대한 분석

조성호 ( Cho Sung Ho ) 한국인터넷정보학회 2005 인터넷정보학회논문지 Vol.6 No.5

이동 컴퓨팅 환경에서 캐싱은 통신대역폭의 한계, 자원의 제약과 잦은 접속단절의 영향을 줄일 수 있는 중요한 기술이다. 이동 컴퓨팅의 이러한 제약과 접속단절을 완화하기 위하여 방송 기반의 새로운 캐싱 기법이 소개되었다. 이 논문에서는 새로운 방송기반 캐쉬 프로토콜을 제안하고 다중버전 방식 및 확인보고 방식과 같이 잘 알려진 기법과 비교한다. 모의실험을 통하여 충돌을 검출하고 해결하는 여러 접근방법들의 특징을 보여준다. 또한, 제안하는 기법이 다른 방식에 비하여 공간 및 계산 부하가 적다는 것을 보인다. Caching in mobile computing environments is an important technique that will reduce the effects such as limitation of bandwidth, restriction of resources and frequent disconnection. To reduce limitation and disconnection problems in mobile computing, a new form of caching system have been proposed based on a broadcast approach. This paper proposes a broadcast based cache protocol and examines the behaviors of the proposed scheme and well known schemes such as multiversion based scheme and Certification Reports. By a detailed simulation, we show some characteristics of different approaches to detect and resolve conflicts. We also show proposed scheme out performs other schemes with a low space and operation overhead.

RMCC: An Efficient Cooperative Caching Scheme for Mobile Ad-hoc Networks

Po-Jen Chuang,Yu-Yiu Chen,Hang-Li Chen 보안공학연구지원센터 2013 International Journal of Future Generation Communi Vol.6 No.3

계층적 캐시 기법을 이용한 대용량 웹 검색 질의 처리 시스템의 구현

임성채(Lim Sung Chae) 한국정보과학회 2008 정보과학회 컴퓨팅의 실제 논문지 Vol.14 No.7

웹을 이용한 정보 공개 및 검색이 확대됨에 따라 웹 검색 엔진도 지속적인 주목을 받고 있다. 이에 따라 웹 검색 엔진의 다양한 기술적 문제를 해결하고자 하는 연구가 있었음에도 웹 검색 엔진의 질의 처리 시스템에 대한 기술적 내용은 잘 다뤄지지 않았다. 질의 처리 시스템의 경우 소프트웨어 아키텍처나 운영 기법을 고안하기 어렵기 때문에 본 논문에서는 구현된 상용 시스템을 바탕으로 관련 기술을 소개하고자 한다. 구현된 질의 처리 시스템은 6,500 만개 웹 문서를 색인하여 일 500만개 이상의 사용자 질의 요청을 수행하는 큰 규모의 시스템이다. 구현한 시스템은 질의 처리 결과를 재사용하기 위해 계층적 캐시 기법을 적용했으며, 저장된 캐시 데이타는 4계층으로 구성된 데이타 저장소에 분산 저장되는 것이 특징이다. 계층적 캐시 기법을 통해 질의 처리 용량을 400% 정도로 향상 시킬 수 있었으며 이를 통해 서버 구축 비용을 70% 정도 절감할 수 있었다. With the increasing demands of information sharing and searches via the web, the web search engine has drawn much attention. Although many researches have been done to solve technical challenges to build the web search engine, the issue regarding its query processing system is rarely dealt with. Since the software architecture and operational schemes of the query processing system are hard to elaborate, we here present related techniques implemented on a commercial system. The implemented system is a very large-scale system that can process 5-million user queries per day by using index files built on about 65-million web pages. We implement a multi-level cache scheme to save already returned query results for performance considerations, and the multi-level cache is managed in 4-level cache storage areas. Using the multi-level cache, we can improve the system throughput by a factor of 4, thereby reducing around 70% of the server cost.

A New Distributed Caching Technique for Accelerating the Web Query Processing

Sungchae Lim,Chang-Sup Park 보안공학연구지원센터 2013 International Journal of Software Engineering and Vol.7 No.3