• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2319-2337
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• 2019

In this paper, we study the distributed cooperative caching for Internet content providers in a small cell of heterogeneous network (HetNet). A general framework based on bankruptcy game model is put forth for finding the optimal caching policy. In this framework, the small cell and different content providers are modeled as bankrupt company and players, respectively. By introducing strategic decisions into the bankruptcy game, we propose a caching value assessment algorithm based on analytic hierarchy process in the framework of bankruptcy game theory to optimize the caching strategy and increase cache hit ratio. Our analysis shows that resource utilization can be improved through cooperative sharing while considering content providers' satisfaction. When the cache value is measured by multiple factors, not just popularity, the cache hit rate for user access is also increased. Simulation results show that our approach can improve the cache hit rate while ensuring the fairness of the distribution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3135-3148
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• 2013

The popularization of streaming networks and mobile devices brings a new kind of network called mobile peer-assisted streaming network. In this network, service provider not only offers downloading services, but also pre-pushes resources to users for caching. Users can download their demanded resources while working as servers for uploading the cached data. Also the mobile characteristic makes high package losing probability in this network. So we study how the service provider pre-pushes or the user downloads resources efficiently and effectively while considering the package losing in this paper. We build utility models for service provider and user, and solve the models using Bellman's theory to achieve Nash Equilibrium which shows the service provider's optimal pre-pushing speed and user's optimal downloading speed. The numerical simulation demonstrates the efficiency and effectiveness of our proposed pre-pushing and downloading scheme by comparing to the traditional scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4268-4290
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• 2015

Future mobile communications face enormous challenges as traditional voice services are replaced with increasing mobile multimedia and data services. To address the vast data traffic volume and the requirement of user Quality of Experience (QoE) in the next generation mobile networks, it is imperative to develop efficient content distribution technique, aiming at significantly reducing redundant data transmissions and improving content delivery performance. On the other hand, in recent years cloud computing as a promising new content-centric paradigm is exploited to fulfil the multimedia requirements by provisioning data and computing resources on demand. In this paper, we propose a cooperative caching framework which implements State based Content Distribution (SCD) algorithm for future mobile networks. In our proposed framework, cloud service providers deploy a plurality of cloudlets in the network forming a Distributed Cloud Service Network (DCSN), and pre-allocate content services in local cloudlets to avoid redundant content transmissions. We use content popularity and content state which is determined by content requests, editorial updates and new arrivals to formulate a content distribution optimization model. Data contents are deployed in local cloudlets according to the optimal solution to achieve the lowest average content delivery latency. We use simulation experiments to validate the effectiveness of our proposed framework. Numerical results show that the proposed framework can significantly improve content cache hit rate, reduce content delivery latency and outbound traffic volume in comparison with known existing caching strategies.

• Industrial Engineering and Management Systems
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• 제11권1호
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• pp.82-86
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• 2012

In For the past few years, query log data has been collected to find user's behavior in using the site. Many researches have studied on the usage of query logs to extract user's preference, recommend personalization, improve caching and pre-fetching of Web objects, build better adaptive user interfaces, and also to improve Web search for a search engine application. A query log contain data such as the client's IP address, time and date of request, the resources or page requested, status of request HTTP method used and the type of browser and operating system. A query log can offer valuable insight into web site usage. A proper compilation and interpretation of query log can provide a baseline of statistics that indicate the usage levels of website and can be used as tool to assist decision making in management activities. In this paper we want to discuss on the tasks performed of query logs in pre-processing of web usage mining. We will use query logs from an online newspaper company. The query logs will undergo pre-processing stage, in which the clickstream data is cleaned and partitioned into a set of user interactions which will represent the activities of each user during their visits to the site. The query logs will undergo essential task in pre-processing which are data cleaning and user identification.

• 융합정보논문지
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• 제9권2호
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• pp.17-22
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• 2019

캐시는 클라이언트의 응답 시간을 향상 시켜 대역폭을 줄여 효과적인 면을 보이는 기법이다. 하지만 캐시 기법이 어느 기법들과 같이 취약점이 존재한다. 웹 캐시는 편리성이 있지만 해킹에 악용되어 문제가 발생할 가능성이 있다. 웹 캐시의 문제점은 주로 캐시 미스와 과도한 캐시 선인출로 인해 발생한다. 캐시 미스가 높고 과도하게 선인출을 하게 되면 캐시는 오히려 취약점이 되어 안전한 데이터를 변형 시키는 등 오류를 발생시키며 사용자의 클라이언트와 시스템 모두 문제가 생기게 된다. 사용자는 캐시 감염, 오류의 대응책을 미리 숙지를 하게 된다면 더 이상 캐시에 관한 오류, 감염 발생에 문제점을 느끼지 못하게 될 것이다. 따라서 본 연구서는 네 가지의 캐시 감염, 오류에 대한 대응책을 사용자에게 제안하여 웹캐시 감염에 대한 대응책을 제시하였다.