Pervasive Data Access in Wireless and Mobile Computing Environments

The rapid advance of wireless and portable computing technology has brought a lot of research interests and momentum to the area of mobile computing. One of the research focus is on pervasive data access. with wireless connections, users can access information at any place at any time. However, various constraints such as limited client capability, limited bandwidth, weak connectivity, and client mobility impose many challenging technical issues. In the past years, tremendous research efforts have been put forth to address the issues related to pervasive data access. A number of interesting research results were reported in the literature. This survey paper reviews important works in two important dimensions of pervasive data access: data broadcast and client caching. In addition, data access techniques aiming at various application requirements (such as time, location, semantics and reliability) are covered

Location-aware cache replacement for mobile environments

Traditional cache replacement policies rely on the temporal locality of users' access pattern to improve cache performance. These policies, however, are not ideal in supporting mobile clients. As mobile clients can move freely from one location to another, their access pattern not only exhibits temporal locality, but also exhibits spatial locality. In order to ensure efficient cache utilisation, it is important to take into consideration the location and movement direction of mobile clients when performing cache replacement. In this paper. we propose a mobility-aware cache replacement policy, called MARS, suitable for wireless environments. MARS takes into account important factors (e.g. client access rate, access probability, update probability and client location) in order to improve the effectiveness of onboard caching for mobile clients. Test results show that MARS consistently outperforms existing cache replacement policies and significantly improves mobile clients' cache hit ratio

Data Management in Location-Dependent Information Services: Challenges and Issues

this article, we discuss location -dependent information access in a mobile-pervasive environment, in particular in a cellular mobile system, and present new research issues arising from on-demand access, broadcast, and data cachin

Data Replication for Improving Data Accessibility in Ad Hoc Networks

In ad hoc networks, due to frequent network partition, data accessibility is lower than that in conventional fixed networks. In this paper, we solve this problem by replicating data items on mobile hosts. First, we propose three replica allocation methods assuming that each data item is not updated. In these three methods, we take into account the access frequency from mobile hosts to each data item and the status of the network connection. Then, we extend the proposed methods by considering aperiodic updates and integrating user profiles consisting of mobile users\u27\u27 schedules, access behavior, and read/write patterns. We also show the results of simulation experiments regarding the performance evaluation of our proposed method

SwiftCache: Model-Based Learning for Dynamic Content Caching in CDNs

We introduce SwiftCache, a "fresh" learning-based caching framework designed for content distribution networks (CDNs) featuring distributed front-end local caches and a dynamic back-end database. Users prefer the most recent version of the dynamically updated content, while the local caches lack knowledge of item popularity and refresh rates. We first explore scenarios with requests arriving at a local cache following a Poisson process, whereby we prove that the optimal policy features a threshold-based structure with updates occurring solely at request arrivals. Leveraging these findings, SwiftCache is proposed as a model-based learning framework for dynamic content caching. The simulation demonstrates near-optimal cost for Poisson process arrivals and strong performance with limited cache sizes. For more general environments, we present a model-free Reinforcement Learning (RL) based caching policy without prior statistical assumptions. The model-based policy performs well compared to the model-free policy when the variance of interarrival times remains moderate. However, as the variance increases, RL slightly outperforms model-based learning at the cost of longer training times, and higher computational resource consumption. Model-based learning's adaptability to environmental changes without retraining positions it as a practical choice for dynamic network environments. Distributed edge caches can utilize this approach in a decentralized manner to effectively meet the evolving behaviors of users.Comment: arXiv admin note: text overlap with arXiv:2401.0361

Named Data Networking in Vehicular Ad hoc Networks: State-of-the-Art and Challenges

International audienceInformation-Centric Networking (ICN) has been proposed as one of the future Internet architectures. It is poised to address the challenges faced by today's Internet that include, but not limited to, scalability, addressing, security, and privacy. Furthermore, it also aims at meeting the requirements for new emerging Internet applications. To realize ICN, Named Data Networking (NDN) is one of the recent implementations of ICN that provides a suitable communication approach due to its clean slate design and simple communication model. There are a plethora of applications realized through ICN in different domains where data is the focal point of communication. One such domain is Intelligent Transportation System (ITS) realized through Vehicular Ad hoc NETwork (VANET) where vehicles exchange information and content with each other and with the infrastructure. To date, excellent research results have been yielded in the VANET domain aiming at safe, reliable, and infotainment-rich driving experience. However, due to the dynamic topologies, host-centric model, and ephemeral nature of vehicular communication, various challenges are faced by VANET that hinder the realization of successful vehicular networks and adversely affect the data dissemination, content delivery, and user experiences. To fill these gaps, NDN has been extensively used as underlying communication paradigm for VANET. Inspired by the extensive research results in NDN-based VANET, in this paper, we provide a detailed and systematic review of NDN-driven VANET. More precisely, we investigate the role of NDN in VANET and discuss the feasibility of NDN architecture in VANET environment. Subsequently, we cover in detail, NDN-based naming, routing and forwarding, caching, mobility, and security mechanism for VANET. Furthermore, we discuss the existing standards, solutions, and simulation tools used in NDN-based VANET. Finally, we also identify open challenges and issues faced by NDN-driven VANET and highlight future research directions that should be addressed by the research community

Cross-validation based man-in-the-middle attack protection

A thesis submitted to the University of Bedfordshire, in fulfilment of the requirements for the degree of Master of Science by researchIn recent years, computer network has widely used in almost all areas of our social life. It has been profoundly changing the way of our living. However, various network attacks have become an increasingly problem at the same time. In local area networks, Man-in-the-Middle attack, as one kind of ARP attack, is the most common attack. This research implemented a cross-validation based Man-in-the-Middle attack protection method (CVP). This approach enables a host to check whether another host that responds the initialising host with an ARP reply packet is genuine. It then allows the ARP cache table of the initialising hosts to be updated with the MAC address and IP address pairs of the genuine host and to place the MAC address of inauthentic hosts into a blacklist. This research introduced ARP and ICMP firstly, including the structure of ARP and ICMP packets, and their workflows. Secondly, this research discussed the types of ARP attacks and the existing ARP attacks protection methods, including their principles, applicable environment, advantages and disadvantages. Then, this research proposed and implemented a cross-validation based Man-in-the-Middle attack protection method. Simulations and experiments were performed to examine the effect of CVP method. The results show the effectiveness of the proposed cross-validation based method in protecting network from Man-in-the-Middle attack. Compared with the existing Man-in-the-Middle attack protection methods, CVP requires no extra devices and administration, leading to more secure local area networks and low cost. It also has made a “tabu” to attackers. That is, it places the MAC address of attackers into a blacklist. So they will be identified immediately if they try to attack the network again

SISTEMI PER LA MOBILITÀ DEGLI UTENTI E DEGLI APPLICATIVI IN RETI WIRED E WIRELESS

The words mobility and network are found together in many contexts. The issue alone of modeling geographical user mobility in wireless networks has countless applications. Depending on one’s background, the concept is investigated with very different tools and aims. Moreover, the last decade saw also a growing interest in code mobility, i.e. the possibility for soft-ware applications (or parts thereof) to migrate and keeps working in different devices and environ-ments. A notable real-life and successful application is distributed computing, which under certain hypothesis can void the need of expensive supercomputers. The general rationale is splitting a very demanding computing task into a large number of independent sub-problems, each addressable by limited-power machines, weakly connected (typically through the Internet, the quintessence of a wired network). Following this lines of thought, we organized this thesis in two distinct and independent parts: Part I It deals with audio fingerprinting, and a special emphasis is put on the application of broadcast mon-itoring and on the implementation aspects. Although the problem is tackled from many sides, one of the most prominent difficulties is the high computing power required for the task. We thus devised and operated a distributed-computing solution, which is described in detail. Tests were conducted on the computing cluster available at the Department of Engineering of the University of Ferrara. Part II It focuses instead on wireless networks. Even if the approach is quite general, the stress is on WiFi networks. More specifically, we tried to evaluate how mobile-users’ experience can be improved. Two tools are considered. In the first place, we wrote a packet-level simulator and used it to esti-mate the impact of pricing strategies in allocating the bandwidth resource, finding out the need for such solutions. Secondly, we developed a high-level simulator that strongly advises to deepen the topic of user cooperation for the selection of the “best” point of access, when many are available. We also propose one such policy