• International Journal of Internet, Broadcasting and Communication
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• 제14권1호
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• pp.31-36
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• 2022

Interval caching is one of the representative caching strategies used in multimedia streaming systems. However, there has been no theoretical analysis on interval caching. In this paper, we present an optimality proof of the interval caching policy. Specifically, we propose a caching performance model for multimedia streaming systems and show the optimality of the interval caching policy based on this model.

• 한국정보과학회논문지:정보통신
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• 제32권4호
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• pp.535-542
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• 2005

무선 컴퓨팅 환경에서 데이타 방송 기법은 다수의 클라이언트에게 데이타를 전송하는 유용한 기법이다. 일반적으로 낮은 대역폭을 갖는 데이타 방송 시스템에서 캐싱은 대역폭에 대한 클라이언트들의 경쟁을 줄임으로써 응답 시간을 향상시키기 위해 도입된다. 본 논문에서는, 클라이언트가 유지하는 정보를 이용하는 기존 연구와 달리 서버가 유지하는 클라이언트의 데이타 요구에 관한 정보를 이용하는 캐싱 전략들을 제시하고 제안한 전략들의 성능을 시뮬레이션을 통하여 평가한다. 성능 평가에 따르면, 서버에서 유지하는 인기도와 대기 시간 정보를 함께 고려하는 전략이 다른 전략들보다 전반적으로 좋은 성능을 보여 주고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권5호
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• pp.2398-2415
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• 2017

Content-Centric Networking (CCN) is a new Internet architecture with routing and caching centered on contents. Through its receiver-driven and connectionless communication model, CCN natively supports the seamless mobility of nodes and scalable content acquisition. In-network caching is one of the core technologies in CCN, and the research of efficient caching scheme becomes increasingly attractive. To address the problem of unbalanced cache load distribution in some existing caching strategies, this paper presents a neighbor cooperation based in-network caching scheme. In this scheme, the node with the highest betweenness centrality in the content delivery path is selected as the central caching node and the area of its ego network is selected as the caching area. When the caching node has no sufficient resource, part of its cached contents will be picked out and transferred to the appropriate neighbor by comprehensively considering the factors, such as available node cache, cache replacement rate and link stability between nodes. Simulation results show that our scheme can effectively enhance the utilization of cache resources and improve cache hit rate and average access cost.

• 한국군사과학기술학회지
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• 제17권5호
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• pp.637-642
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• 2014

Military communications have limited resources such as poor bandwidth and insufficient link capacity. Numerous hosts in conventional IP networks, including the Tactical Information Communication Network (TICN), the tactical communication system of the Army, focus heavy traffic on a single server via end-to-end connections and in which data delivery latency is caused by exchanging routing information. Content-Centric Networking (CCN), one framework of Information-Centric Networking (ICN), is a novel Internet paradigm in which data can be accessed by the name of the content instead of the location information. This paper provides content caching strategies for applying CCN to military tactical IP networks based on TICN environment.

• Journal of Communications and Networks
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• 제7권2호
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• pp.144-156
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• 2005

Video streaming over wireless networks is challenging due to node mobility and high channel error rate. In this paper, we propose a multi-source video streaming (MUVIS) system to support high quality video streaming service over IEEE 802.1l-based wireless networks. We begin by collocating a streaming proxy with the wireless access point to help leverage both the media server and peers in the WLAN. By tracking the peer mobility patterns and performing content discovery among peers, we construct a multi-source sender group and stream video using a rate-distortion optimized scheme. We formulate such a multi-source streaming scenario as a combinatorial packet scheduling problem and introduce the concept of asynchronous clocks to decouple the problem into three steps. First, we decide the membership of the multisource sender group based on the mobility pattern tracking, available video content in each peer and the bandwidth each peer allocates to the multi-source streaming service. Then, we select one sender from the sender group in each optimization instance using asynchronous clocks. Finally, we apply the point-to-point rate-distortion optimization framework between the selected sender-receiver pair. In addition, we implement two different caching strategies, simple caching simple fetching (SCSF) and distortion minimized smart caching (DMSC), in the proxy to investigate the effect of caching on the streaming performance. To design more realistic simulation models, we use the empirical results from corporate wireless networks to generate node mobility. Simulation results show that our proposed multi-source streaming scheme has better performance than the traditional server-only streaming scheme and that proxy-based caching can potentially improve video streaming performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권5호
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• pp.1238-1259
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• 2024

Previous studies on joint optimization of computation offloading and service caching policies in Mobile Edge Computing (MEC) have often neglected the impact of dependency-aware subtasks, edge server resource constraints, and multiple users on policy formulation. To remedy this deficiency, this paper proposes a many-objective joint optimization dependency-aware task offloading and service caching model (MaJDTOSC). MaJDTOSC considers the impact of dependencies between subtasks on the joint optimization problem of task offloading and service caching in multi-user, resource-constrained MEC scenarios, and takes the task completion time, energy consumption, subtask hit rate, load variability, and storage resource utilization as optimization objectives. Meanwhile, in order to better solve MaJDTOSC, a many-objective evolutionary algorithm TSMSNSGAIII based on a three-stage mating selection strategy is proposed. Simulation results show that TSMSNSGAIII exhibits an excellent and stable performance in solving MaJDTOSC with different number of users setting and can converge faster. Therefore, it is believed that TSMSNSGAIII can provide appropriate sub-task offloading and service caching strategies in multi-user and resource-constrained MEC scenarios, which can greatly improve the system offloading efficiency and enhance the user experience.

• 한국시뮬레이션학회논문지
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• 제12권2호
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• pp.25-34
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• 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.

• 인터넷정보학회논문지
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• 제5권6호
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• pp.103-110
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• 2004

본 논문에서는 웹 서버 성능에 있어 캐싱 정책의 영향을 분석하고 연구하였다. 새롭게 제안한 파일 타입 기반 캐싱 정책은 캐시안의 크고 작은 파일간에 균형 잡힌 결과를 갖도록 지원하며, 뿐만 아니라 작은 파일과 큰 파일에 대한 요청에 훌륭한 성능을 나타낸다. 본 논문에서는 파일 타입 기반 캐싱이 적중률과 바이트적중률 모두 다 좋은 결과를 나타냄을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.514-535
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• 2019

Information-centric networks operate under the assumption that all network components have built-in caching capabilities. Integrating the caching strategies of information centric networking (ICN) with wireless virtualization improves the gain of virtual infrastructure content caching. In this paper, we propose a framework for software-defined information centric virtualized wireless device-to-device (D2D) networks. Enabling D2D communications in virtualized ICN increases the spectral efficiency due to reuse and proximity gains while the software-defined network (SDN) as a platform also simplifies the computational overhead. In this framework, we propose a joint virtual resource and cache allocation solution for latency-sensitive applications in the next-generation cellular networks. As the formulated problem is NP-hard, we design low-complexity heuristic algorithms which are intuitive and efficient. In our proposed framework, different services can share a pool of infrastructure items. We evaluate our proposed framework and algorithm through extensive simulations. The results demonstrate significant improvements in terms of visiting latency, end user QoE, InP resource utilization and MVNO utility gain.

• 대한임베디드공학회논문지
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• 제13권3호
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• pp.109-116
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• 2018

SSDs that are not allowed in-place update within the allocated page cause another allocation of a new page that will replace the previous page at the moment data modification occurs. This intrinsic characteristic of SSDs requires many changes to the existing HDD-based IO theory. In this paper, we conduct a performance comparison of FTL caching strategy in perspective of cache hashing (Global vs. grouped) and caching algorithm (LRU vs. NUR) through a simulation. Experimental results show that in terms of energy consumption for flash operation the grouped management of cache is not suitable and NUR algorithm is superior to LRU algorithm. In particular, we found that the cache hit ratio of LRU algorithm is about 10% point higher than that of NUR algorithm while the energy consumption of LRU algorithm is about 32% high.