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Vehicular network standard demands a short range reliable vehicle-to-vehicle (V2V) communication with high mobility, also increasing amount of downloaded data in short encounters. Satisfying demands of clients with minimum number of transmissions using index coding has proven notable significance in wireless ad-hoc networks. The proper encoding at the server with side information leads to simultaneous...
Decentralized coded caching is applicable in scenarios where the server does not have enough knowledge about the entire cache network to perform centralized coordination during prefetching, such as when the server is uninformed of the number of active users and their identities in a wireless or mobile environment. Most of known decentralized strategies use random uncoded prefetching followed by coded...
Many large-scale distributed storage systems deploy erasure coding to protect data from frequent server failures for cost reason. In most of these systems, newly inserted data is first replicated across different storage servers and then migrated to erasure coded. Although this offline encoding manner can improve data access before data is erasure coded for some storage systems, it helps little and...
Distributed storage systems are known to be susceptible to long tails in response time. It has been shown that in modern online applications such as Bing, Facebook, and Amazon, the long tail of latency is of particular concern, with 99.9th percentile response times being orders of magnitude worse than the mean. As erasure codes emerge as a popular technique in distributed storage to achieve high data...
360° video streaming to clients using Virtual Reality head mounted displays is a challenge for traditional video delivery. As transmission of the complete content in a desirable quality sacrifices a large fraction of available client and network resources, adaptivity to the user viewport promises substantial benefits. An efficient way to achieve viewport adaptive streaming without per-user or per-orientation...
A lot of research shows that network coding can significantly improve the performance of multi-cast transmission. However, due to the inherent disadvantage of network coding, it is very vulnerable to pollution attacks in which adversaries can inject bogus data. Moreover, those bogus data will be used with legitimate data at the downstream nodes, resulting in the failure of decoding original data as...
Motivated by applications of distributed storage systems to key-value stores, recently, the multi-version coding problem was proposed to store data that is frequently being updated in a distributed storage system. In particular, in multi-version coding, it is desired to store the data consistently, that is, even if all servers do not receive the data updates simultaneously, the decoder can recover...
Caching is an effective way to reduce peak-hour network traffic congestion by storing some contents at user's local cache. Maddah-Ali and Niesen (MAN) initiated a fundamental study of caching systems by proposing a scheme (with uncoded cache placement and linear network coding delivery) that is provably optimal to within a factor 4.7. In this paper, when the cache contents and the user demands are...
We consider a content delivery network where multiple servers are connected to multiple cache-enabled clients. Clients request their corresponding contents from the servers and servers collaboratively transmit packets to fulfill all the requests. It is assumed that some contents are stored in the caches in off-peak time of the network without knowing the actual requests, the so called cache content...
The question of under what condition some side information for index coding can be removed without affecting the capacity region is studied, which was originally posed by Tahmasbi, Shahrasbi, and Gohari. To answer this question, the notion of unicycle for the side information graph is introduced and it is shown that any edge that belongs to a unicycle is critical, namely, it cannot be removed without...
Wireless sensor networks (WSN) provide attractive solutions for data exchange in a variety of applications from military surveillance to medical and environmental monitoring. The commonality in all such applications is that the data collected in some nodes of the network is needed at some other nodes, for instance in a data collector node. The nodes are typically limited in terms of power, memory,...
We study the problem of secure transmission over a caching D2D network. In this model, end users can prefetch a part of popular contents in their local cache. Users make arbitrary requests from the library of available files and interact with each other to deliver requested contents from the local cache to jointly satisfy their demands. The transmission between the users is wiretapped by an external...
Cloud computing allows users to migrate their calculations to distributed environment which will utilize more number of resources to complete execution quickly. Virtualization means multiple virtual machines (VM) on single physical machine.During process of migration, VM move one physical machine to another. In offline migration, process is stopped till the virtual machine can continue on target machine,...
Caching decreases content access time by keeping contents closer to the clients. In this paper we show that network coding chunks of different contents and storing them in cache, can be beneficial. Recent research considers caching network coded chunks of same content, but not different contents. This paper proposes three different methods, IP, layered-IP and Greedy algorithm, with different performance...
We consider a network consisting of a file server connected through a shared link to a number of users, each equipped with a cache. Knowing the popularity distribution of the files in the database, the goal is to optimally populate the caches such as to minimize the expected load of the shared link. For a single user, it is well known that caching the most popular files is optimal in this setting...
In lambda-grid networks, data files are stored on file servers as replicas, and those replicas are downloaded in parallel to reduce downloading time. However, parallel downloading raises the blocking probability of lightpath establishments because parallel downloading wastes many wavelength resources. To resolve this problem, we propose a parallel downloading scheme with network coding which encodes...
Autonomic networks are networks that are self- organized with decentralized control and management. Accurate trust establishment and maintenance is essential for secure and reliable message transmissions in autonomic networks. Because of the mobility and dynamics, trust management in autonomic networks is a much more dynamic problem than in traditional server-based networks. In traditional networks,...
This work addresses the transmission of motion JPEG2000 over JPIP, proposing a Variable Bit-Rate (VBR) server-driven policy aimed to minimize the overall distortion of the transmitted frames. In addition, a block-wise strategy of quality layer truncation is introduced to enhance the quality of transmitted frames containing insufficient quality layers. We pose these matters in a general framework where...
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