A dynamic content distribution scheme for decentralized sharing in tourist hotspots
- Authors: Kaisar, Shahriar , Kamruzzaman, Joarder , Karmakar, Gour
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Network and Computer Applications Vol. 129, no. (2019), p. 9-24
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- Description: Decentralized content sharing (DCS) is emerging as a suitable platform for smart mobile device users to generate and share contents seamlessly without the requirement of a centralized server. This feature is particularly important for places that lack Internet coverage such as tourist attractions where users can form an ad-hoc network and communicate opportunistically to share contents. Existing DCS approaches when applied for such type of places suffer from low delivery success rate and high latency. Although a handful of recent approaches have specifically targeted improvement of content delivery service in tourist spot like scenario, these and other DCS approaches do not focus on contents’ demand and supply which vary considerably due to visitor in-and-out flow and occurrence of influencing events. This is further compounded by the lack of any content distribution (replication) scheme. The content delivery service will be improved if contents can be proactively distributed in strategic positions based on dynamic demand and supply and medium access contention. In this paper, we propose a dynamic content distribution scheme (DCDS) considering these practical issues for sharing contents in tourist attractions. Simulation results show that the proposed approach significantly improves (7
Spectral and energy efficiency maximization for content-centric c-rans with edge caching
- Authors: Vu, Tung Thanh , Ngo, Duy Trong , Dao, Minh Ngoc , Durrani, Salman , Middleton, Richard
- Date: 2018
- Type: Text , Journal article
- Relation: IEEE transactions on communications Vol. 66, no. 12 (2018), p. 6628-6642
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- Description: This paper aims to maximize the spectral and energy efficiencies of a content-centric cloud radio access network (C-RAN), where users requesting the same contents are grouped together. Data are transferred from a central baseband unit to multiple remote radio heads (RRHs) equipped with local caches. The RRHs then send the received data to each group's user. Both multicast and unicast schemes are considered for data transmission. We formulate mixed-integer nonlinear problems in which user association, RRH activation, data rate allocation, and signal precoding are jointly designed. These challenging problems are subject to minimum data rate requirements, limited fronthaul capacity, and maximum RRH transmit power. Employing successive convex quadratic programming, we propose iterative algorithms with guaranteed convergence to Fritz John solutions. Numerical results confirm that the proposed joint designs markedly improve the spectral and energy efficiencies of the considered content-centric C-RAN compared to benchmark schemes. Importantly, they show that unicasting outperforms multicasting in terms of spectral efficiency in both cache and cache-less scenarios. In terms of energy efficiency, multicasting is the best choice for the system without cache whereas unicasting is best for the system with cache. Finally, edge caching is shown to improve both spectral and energy efficiencies.
Value-based caching in information-centric wireless body area networks
- Authors: Al-Turjman, Fadi , Imran, Muhammad , Vasilakos, Athanasios
- Date: 2017
- Type: Text , Journal article
- Relation: Sensors (Switzerland) Vol. 17, no. 1 (2017), p.
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- Description: We propose a resilient cache replacement approach based on a Value of sensed Information (VoI) policy. To resolve and fetch content when the origin is not available due to isolated in-network nodes (fragmentation) and harsh operational conditions, we exploit a content caching approach. Our approach depends on four functional parameters in sensory Wireless Body Area Networks (WBANs). These four parameters are: age of data based on periodic request, popularity of on-demand requests, communication interference cost, and the duration for which the sensor node is required to operate in active mode to capture the sensed readings. These parameters are considered together to assign a value to the cached data to retain the most valuable information in the cache for prolonged time periods. The higher the value, the longer the duration for which the data will be retained in the cache. This caching strategy provides significant availability for most valuable and difficult to retrieve data in the WBANs. Extensive simulations are performed to compare the proposed scheme against other significant caching schemes in the literature while varying critical aspects in WBANs (e.g., data popularity, cache size, publisher load, connectivity-degree, and severe probabilities of node failures). These simulation results indicate that the proposed VoI-based approach is a valid tool for the retrieval of cached content in disruptive and challenging scenarios, such as the one experienced in WBANs, since it allows the retrieval of content for a long period even while experiencing severe in-network node failures. © 2017 by the authors; licensee MDPI, Basel, Switzerland.
An efficient caching policy for content retrieval in autonomous connected vehicles
- Authors: Rahim, Muddasir , Javed, Muhammad , Alvi, Alvi , Imran, Muhammad
- Date: 2020
- Type: Text , Journal article
- Relation: Transportation Research Part A: Policy and Practice Vol. 140, no. (2020), p. 142-152
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- Description: Connected vehicles will enable the smart and autonomous transportation systems in the future. Cellular Vehicle-to-Everything (C-V2X) communication will provide wireless connectivity to enable large number of connected vehicle applications. Vehicles will receive traffic and infotainment contents from the city traffic command center using C-V2X communications. In this context, infrastructure Road Side Units (RSUs) will cache urgent and popular data in their memory storage, hence providing vehicles to retrieve information from a closer vicinity at a RSU. In this paper, we present a content caching policy for the connected vehicles operator to improve the efficiency of the content retrieval in terms of download rate and delay. We propose the utility functions for the RSUs and vehicles to cache a particular content at a given RSU. Moreover, Gale-Shapley stable matching algorithm is used to efficiently allocate RSU cache to the contents. We also provide rules to update the cache slots. The proposed caching scheme is compared with random caching policy and market matching based caching policies. Results show that the proposed content caching policy improves the efficiency of the content retrieval with 60% more data transmission with reduced downloading time and better link utilization as compared to other two scheme. © 2020 Elsevier Ltd
Efficient prefetching and client-side caching algorithms for improving the performance of read operations in distributed file systems
- Authors: Nalajala, Anusha , Ragunathan, Thirumalaisamy , Naha, Ranesh
- Date: 2022
- Type: Journal article
- Relation: IEEE access Vol. 10, no. (2022), p. 126232-126252
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- Description: Modern web applications are deployed in cloud computing systems because they support unlimited storage and computing power. One of the main back-end storage components of this cloud computing system is the distributed file system which allows massive amounts of data to be stored and accessed. In most web applications deployed in such systems, read operations are performed more frequently than write operations. Consequently, increasing the efficiency of read operations in distributed file systems is a challenging and important research problem. The two main procedures used in distributed file systems to improve the performance of read operations are prefetching and caching. In this paper, we proposed novel prefetching and multi-level caching algorithms based on the Access-Frequency and Access-Recency ranking of file blocks that were previously accessed by client application programs. We also proposed new augmented ranking algorithms for prefetching file blocks by combining the Access-Frequency and Access-Recency ranking of the file blocks. We used rank-based replacement algorithms to replace file blocks in the cache. The simulation results show that, the proposed algorithms improve the performance of read operations on distributed file systems by 29% to 77% in comparison to algorithms proposed in the literature.