36 research outputs found

    Scale-free topology optimization for software-defined wireless sensor networks: A cyber-physical system

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    Due to the limited resource and vulnerability in wireless sensor networks, maximizing the network lifetime and improving network survivability have become the top priority problem in network topology optimization. This article presents a wireless sensor networks topology optimization model based on complex network theory and cyber-physical systems using software-defined wireless sensor network architecture. The multiple-factor-driven virtual force field and network division–oriented particle swarm algorithm are introduced into the deployment strategy of super-node for the implementation in wireless sensor networks topology initialization, which help to rationally allocate heterogeneous network resources and balance the energy consumption in wireless sensor networks. Furthermore, the preferential attachment scheme guided by corresponding priority of crucial sensors is added into scale-free structure for optimization in topology evolution process and for protection of vulnerable nodes in wireless sensor networks. Software-defined wireless sensor network–based functional architecture is adopted to optimize the network evolution rules and algorithm parameters using information cognition and flow-table configure mode. The theoretical analysis and experimental results demonstrate that the proposed wireless sensor networks topology optimization model possesses both the small-world effect and the scale-free property, which can contribute to extend the lifetime of wireless sensor networks with energy efficiency and improve the robustness of wireless sensor networks with structure invulnerability

    A Comprehensive Survey on Orbital Edge Computing: Systems, Applications, and Algorithms

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    The number of satellites, especially those operating in low-earth orbit (LEO), is exploding in recent years. Additionally, the use of COTS hardware into those satellites enables a new paradigm of computing: orbital edge computing (OEC). OEC entails more technically advanced steps compared to single-satellite computing. This feature allows for vast design spaces with multiple parameters, rendering several novel approaches feasible. The mobility of LEO satellites in the network and limited resources of communication, computation, and storage make it challenging to design an appropriate scheduling algorithm for specific tasks in comparison to traditional ground-based edge computing. This article comprehensively surveys the significant areas of focus in orbital edge computing, which include protocol optimization, mobility management, and resource allocation. This article provides the first comprehensive survey of OEC. Previous survey papers have only concentrated on ground-based edge computing or the integration of space and ground technologies. This article presents a review of recent research from 2000 to 2023 on orbital edge computing that covers network design, computation offloading, resource allocation, performance analysis, and optimization. Moreover, having discussed several related works, both technological challenges and future directions are highlighted in the field.Comment: 18 pages, 9 figures and 5 table

    Intrusion Detection Systems in Cloud Computing: A Contemporary Review of Techniques and Solutions

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    Rapid growth of resources and escalating cost of infrastructure is leading organizations to adopt cloud computing. Cloud computing provides high performance, efficient utilization, and on-demand availability of resources. However, the cloud environment is vulnerable to different kinds of intrusion attacks which involve installing malicious software and creating backdoors. In a cloud environment, where businesses have hosted important and critical data, the security of underlying technologies becomes crucial. To mitigate the threat to cloud environments, Intrusion Detection Systems (IDS) are a layer of defense. The aim of this survey paper is to review IDS techniques proposed for the cloud. To achieve this objective, the first step is defining the limitations and unique characteristics of each technique. The second step is establishing the criteria to evaluate IDS architectures. In this paper, the criteria used is derived from basic characteristics of cloud. Next step is a comparative analysis of various existing intrusion detection techniques against the criteria. The last step is on the discussion of drawbacks and open issues, comprehended from the evaluation, due to which implementation of IDS in cloud environment face hurdles

    Attacks on self-driving cars and their countermeasures : a survey

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    Intelligent Traffic Systems (ITS) are currently evolving in the form of a cooperative ITS or connected vehicles. Both forms use the data communications between Vehicle-To-Vehicle (V2V), Vehicle-To-Infrastructure (V2I/I2V) and other on-road entities, and are accelerating the adoption of self-driving cars. The development of cyber-physical systems containing advanced sensors, sub-systems, and smart driving assistance applications over the past decade is equipping unmanned aerial and road vehicles with autonomous decision-making capabilities. The level of autonomy depends upon the make-up and degree of sensor sophistication and the vehicle's operational applications. As a result, self-driving cars are being compromised perceived as a serious threat. Therefore, analyzing the threats and attacks on self-driving cars and ITSs, and their corresponding countermeasures to reduce those threats and attacks are needed. For this reason, some survey papers compiling potential attacks on VANETs, ITSs and self-driving cars, and their detection mechanisms are available in the current literature. However, up to our knowledge, they have not covered the real attacks already happened in self-driving cars. To bridge this research gap, in this paper, we analyze the attacks that already targeted self-driving cars and extensively present potential cyber-Attacks and their impacts on those cars along with their vulnerabilities. For recently reported attacks, we describe the possible mitigation strategies taken by the manufacturers and governments. This survey includes recent works on how a self-driving car can ensure resilient operation even under ongoing cyber-Attack. We also provide further research directions to improve the security issues associated with self-driving cars. © 2013 IEEE

    Content Caching and Delivery in Heterogeneous Vehicular Networks

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    Connected and automated vehicles (CAVs), which enable information exchange and content delivery in real time, are expected to revolutionize current transportation systems for better driving safety, traffic efficiency, and environmental sustainability. However, the emerging CAV applications such as content delivery pose stringent requirements on latency, throughput, reliability, and global connectivity. The current wireless networks face significant challenges to satisfy the requirements due to scarce radio spectrum resources, inflexibility to dynamic traffic demands, and geographic-constrained fixed infrastructure deployment. To empower multifarious CAV content delivery, heterogeneous vehicular networks (HetVNets), which integrate the terrestrial networks with aerial networks formed by unmanned aerial vehicles (UAVs) and space networks constituting of low Earth orbit (LEO) satellites, can guarantee reliable, flexible, cost-effective, and globally seamless service provisioning. In addition, edge caching is a promising solution to facilitate content delivery by caching popular files in the HetVNet access points (APs) to relieve the backhaul traffic with a lower delivery delay. The main technical issues are: 1) to fully reveal the potential of HetVNets for content delivery performance enhancement, content caching scheme design in HetVNets should jointly consider network characteristics, vehicle mobility patterns, content popularity, and APs’ caching capacities; 2) to fully exploit the controllable mobility and agility of UAVs to support dynamic vehicular content demands, the caching scheme and trajectory design for UAVs should be jointly optimized, which has not been well addressed due to their intricate inter-coupling relationships; and 3) for caching-based content delivery in HetVNets, a cooperative content delivery scheme should be designed to enable the cooperation among different network segments with ingenious utilization of heterogeneous network resources. In this thesis, we design the content caching and delivery schemes in the caching-enabled HetVNet to address the three technical issues. First, we study the content caching in HetVNets with fixed terrestrial APs including cellular base stations (CBSs), Wi-Fi roadside units (RSUs), and TV white space (TVWS) stations. To characterize the intermittent network connection caused by limited network coverage and high vehicle mobility, we establish an on-off model with service interruptions to describe the vehicular content delivery process. Content coding then is leveraged to resist the impact of unstable network connections and enhance caching efficiency. By jointly considering file characteristics and network conditions, the content placement is formulated as an integer linear programming (ILP) problem. Adopting the idea of the student admission model, the ILP problem is then transformed into a many-to-one matching problem between content files and HetVNet APs and solved by our proposed stable-matching-based caching scheme. Simulation results demonstrate that the proposed scheme can achieve near-optimal performances in terms of delivery delay and offloading ratio with a low complexity. Second, UAV-aided caching is considered to assist vehicular content delivery in aerial-ground vehicular networks (AGVN) and a joint caching and trajectory optimization (JCTO) problem is investigated to jointly optimize content caching, content delivery, and UAV trajectory. To enable real-time decision-making in highly dynamic vehicular networks, we propose a deep supervised learning scheme to solve the JCTO problem. Specifically, we first devise a clustering-based two-layered (CBTL) algorithm to solve the JCTO problem offline. With a given content caching policy, we design a time-based graph decomposition method to jointly optimize content delivery and UAV trajectory, with which we then leverage the particle swarm optimization algorithm to optimize the content caching. We then design a deep supervised learning architecture of the convolutional neural network (CNN) to make online decisions. With the CNN-based model, a function mapping the input network information to output decisions can be intelligently learnt to make timely inferences. Extensive trace-driven experiments are conducted to demonstrate the efficiency of CBTL in solving the JCTO problem and the superior learning performance with the CNN-based model. Third, we investigate caching-assisted cooperative content delivery in space-air-ground integrated vehicular networks (SAGVNs), where vehicular content requests can be cooperatively served by multiple APs in space, aerial, and terrestrial networks. In specific, a joint optimization problem of vehicle-to-AP association, bandwidth allocation, and content delivery ratio, referred to as the ABC problem, is formulated to minimize the overall content delivery delay while satisfying vehicular quality-of-service (QoS) requirements. To address the tightly-coupled optimization variables, we propose a load- and mobility-aware ABC (LMA-ABC) scheme to solve the joint optimization problem as follows. We first decompose the ABC problem to optimize the content delivery ratio. Then the impact of bandwidth allocation on the achievable delay performance is analyzed, and an effect of diminishing delay performance gain is revealed. Based on the analysis results, the LMA-ABC scheme is designed with the consideration of user fairness, load balancing, and vehicle mobility. Simulation results demonstrate that the proposed LMA-ABC scheme can significantly reduce the cooperative content delivery delay compared to the benchmark schemes. In summary, we have investigated the content caching in terrestrial networks with fixed APs, joint caching and trajectory optimization in the AGVN, and caching-assisted cooperative content delivery in the SAGVN. The proposed schemes and theoretical results should provide useful guidelines for future research in the caching scheme design and efficient utilization of network resources in caching-enabled heterogeneous wireless networks

    Actualization of Neo-Sufism:A Case Study of the Tariqa Qadiriyya Naqshabandiyya Pondok Pesantren Suryalaya

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    The ‘New’ Neo-Sufism This book presents the actualization of Neo-Sufism by studying one of the largest tariqas in Indonesia: The Tariqa Qadiriyya Naqshabandiyya Pondok Pesantren Suryalaya (TQN PP Suryalaya). This study was triggered by the fact that much literature on Muslim societies identify tariqas with the rural parts of society and illiterate people. In this view, tariqas represent a waning 'traditional' component in the modern socio-religious order. This image continues to influence general public opinion and scholarship in the Muslim World as well as the West. Encounters between tariqas and modernity are important but they are regrettably under-studied, especially with regard to the Sufi Orders’ resurgence among urban society, the best educated and most modern segments of the middle class. My study on TQN PP Suryalaya shows that the tariqa managed to demonstrate its ability to exist, adapt and play a role in modern Indonesia. The murshids of the tariqa made gradual changes and improvements in the tariqa’s teachings and practices; and they continue to increase their social functions in Modern Muslim society. Because of its ability to adapt, to answer challenges and offer solutions to the people’s problems, the tariqa increasingly came to be noticed and even attracted the interest of the upper middle class, educated circles, and urban communities. In conducting this study, I use the framework of Neo-Sufism to examine TQN PP Suryalaya in the leadership periods of its three murshids: Abah Sepuh (1935-1956), Abah Anom (1956-2011), and Abah Aos (2011-present). Aside from the pro and cons behind the use of the term, scholars still use Neo-Sufism to refer to and portray a reform movement within the tariqa world. The reformed tariqa teachings, its practices, and its actualizations that all fall under the authority of the sheikhs of the tariqa are examined. Some of the questions that are addressed for all three periods are: What was/is the socio-political context of each murshid, the style of their teachings and practice in the tariqa, what reforms in the teachings and practices have they made in the tariqa which can be considered as expressions of “Neo-Sufism”; and how, through socio and political activism, did they actualize the tariqa in each different period in terms of “Neo-Sufism” also with respect to Neo-Sufi orthodoxy? Other issues touched upon in the book include the strategies behind the changes in the tariqa’s leadership in the past and in present-day Indonesia and how the tariqa disseminates its teachings and puts them in practice in the modern world? I did my research by using the participant-observation technique and did my fieldwork in three periods, from March to May 2016, November-December 2016, and March-April 2017. I did one additional fieldwork to rework the thesis from June to August 2018 but when I had the occasion to interview informants outside these periods I, of course, used it. During these periods, I held interviews with TQN PP Suryalaya disciples, talqin deputies, and tariqa leaders especially the current TQN PP Suryalaya sheikh. In this qualitative study, I also rely on literary sources. I expect that my study will contribute to a more reliable and intimate understanding of the tariqa world and that of TQN PP Suryalaya in particular, in the following ways: First, it enhances our understanding of the actualization of Neo-Sufism through the revitalization of the tariqa teachings and practices. Second, it digs out the reasons behind TQN PP Suryalaya’s change of vision and outlook and what role its leaders played (and still play) in this process. Third, my study elucidates the important roles of educated and professional urban and middle-class Muslims in the promotion of changes in TQN PP Suryalaya’s vision and tradition. Forth, my study sheds light on the patterns behind the political behaviour of TQN PP Suryalaya’s leaders. Fifth, my study highlight the dramatic political changes that took place since the tariqa’s inception and how, at the Indonesian national level, these changes prepared the political setting for TQN PP Suryalaya in promoting its adjustments at all levels

    Restoration's return in the age of climate crisis: toward a feminist environmental justice response

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    University of Minnesota Ph.D. dissertation. November 2014. Major: Feminist Studies. Advisor: Dr. Jacquelyn Zita. 1 computer file (PDF); iv, 158 pages.This project is situated at the locus of discourses on feminism, environmental justice, climate change, and ecological restoration. Asking what kinds of responses to climate change are needed on this rapidly-changing planet, and which initiatives will address social and ecological dilemmas simultaneously, I turn to ecological restoration as a troubled but promising field to harness the insights of feminist environmental justice toward intervening in both the causes and consequences of climate change. In order to engender resiliency among human and nonhuman communities, I advocate a contextualized, grassroots response to climate change that I have coined justice-oriented restoration. This ideology and method strengthens voices and movements often marginalized by engaging diverse stakeholders in order to create ecologies responsive to climatically-induced biosocial shifts, as well as the declining field of restoration itself, which climate change threatens to render irrelevant. In so doing, this project contributes to debates on sustainability; to the cross-pollination of the humanities, social sciences, and sciences; and to the momentum building worldwide for community-driven, site-specific adaptations, mitigations, and remediations to environmental vulnerabilities
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