Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical-layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical-layer message authentication is also introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201

LoRaWAN Physical Layer-Based Attacks and Countermeasures, A Review

As LoRaWAN is one of the most popular long-range wireless protocols among low-power IoT applications, more and more focus is shifting towards security. In particular, physical layer topics become relevant to improve the security of LoRaWAN nodes, which are often limited in terms of computational power and communication resources. To this end, e.g., detection methods for wireless attacks improve the integrity and robustness of LoRaWAN access. Further, wireless physical layer techniques have potential to enhance key refreshment and device authentication. In this work, we aim to provide a comprehensive review of various vulnerabilities, countermeasures and security enhancing features concerning the LoRaWAN physical layer. Afterwards, we discuss the impact of the reviewed topics on LoRaWAN security and, subsequently, we identify research gaps as well as promising future research directions

Cyber-Human Systems, Space Technologies, and Threats

CYBER-HUMAN SYSTEMS, SPACE TECHNOLOGIES, AND THREATS is our eighth textbook in a series covering the world of UASs / CUAS/ UUVs / SPACE. Other textbooks in our series are Space Systems Emerging Technologies and Operations; Drone Delivery of CBNRECy – DEW Weapons: Emerging Threats of Mini-Weapons of Mass Destruction and Disruption (WMDD); Disruptive Technologies with applications in Airline, Marine, Defense Industries; Unmanned Vehicle Systems & Operations On Air, Sea, Land; Counter Unmanned Aircraft Systems Technologies and Operations; Unmanned Aircraft Systems in the Cyber Domain: Protecting USA’s Advanced Air Assets, 2nd edition; and Unmanned Aircraft Systems (UAS) in the Cyber Domain Protecting USA’s Advanced Air Assets, 1st edition. Our previous seven titles have received considerable global recognition in the field. (Nichols & Carter, 2022) (Nichols, et al., 2021) (Nichols R. K., et al., 2020) (Nichols R. , et al., 2020) (Nichols R. , et al., 2019) (Nichols R. K., 2018) (Nichols R. K., et al., 2022)https://newprairiepress.org/ebooks/1052/thumbnail.jp

Network coded wireless architecture

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 183-197).Wireless mesh networks promise cheap Internet access, easy deployment, and extended range. In their current form, however, these networks suffer from both limited throughput and low reliability; hence they cannot meet the demands of applications such as file sharing, high definition video, and gaming. Motivated by these problems, we explore an alternative design that addresses these challenges. This dissertation presents a network coded architecture that significantly improves throughput and reliability. It makes a simple yet fundamental switch in network design: instead of routers just storing and forwarding received packets, they mix (or code) packets' content before forwarding. We show through practical systems how routers can exploit this new functionality to harness the intrinsic characteristics of the wireless medium to improve performance. We develop three systems; each reveals a different benefit of our network coded design. COPE observes that wireless broadcast naturally creates an overlap in packets received across routers, and develops a new network coding algorithm to exploit this overlap to deliver the same data in fewer transmissions, thereby improving throughput. ANC pushes network coding to the signal level, showing how to exploit strategic interference to correctly deliver data from concurrent senders, further increasing throughput. Finally, MIXIT presents a symbol-level network code that exploits wireless spatial diversity, forwarding correct symbols even if they are contained in corrupted packets to provide high throughput reliable transfers. The contributions of this dissertation are multifold. First, it builds a strong connection between the theory of network coding and wireless system design. Specifically, the systems presented in this dissertation were the first to show that network coding can be cleanly integrated into the wireless network stack to deliver practical and measurable gains. The work also presents novel algorithms that enrich the theory of network coding, extending it to operate over multiple unicast flows, analog signals, and soft-information.(cont.) Second, we present prototype implementations and testbed evaluations of our systems. Our results show that network coding delivers large performance gains ranging from a few percent to several-fold depending on the traffic mix and the topology. Finally, this work makes a clear departure from conventional network design. Research in wireless networks has largely proceeded in isolation, with the electrical engineers focusing on the physical and lower layers, while the computer scientists worked up from the network layer, with the packet being the only interface. This dissertation pokes a hole in this contract, disposing of artificial abstractions such as indivisible packets and point-to-point links in favor of a more natural abstraction that allows the network and the lower layers to collaborate on the common objectives of improving throughput and reliability using network coding as the building block. At the same time, the design maintains desirable properties such as being distributed, low-complexity, implementable, and integrable with the rest of the network stack.by Sachin Rajsekhar Katti.Ph.D

Spread spectrum-based video watermarking algorithms for copyright protection

Merged with duplicate record 10026.1/2263 on 14.03.2017 by CS (TIS)Digital technologies know an unprecedented expansion in the last years. The consumer can now benefit from hardware and software which was considered state-of-the-art several years ago. The advantages offered by the digital technologies are major but the same digital technology opens the door for unlimited piracy. Copying an analogue VCR tape was certainly possible and relatively easy, in spite of various forms of protection, but due to the analogue environment, the subsequent copies had an inherent loss in quality. This was a natural way of limiting the multiple copying of a video material. With digital technology, this barrier disappears, being possible to make as many copies as desired, without any loss in quality whatsoever. Digital watermarking is one of the best available tools for fighting this threat. The aim of the present work was to develop a digital watermarking system compliant with the recommendations drawn by the EBU, for video broadcast monitoring. Since the watermark can be inserted in either spatial domain or transform domain, this aspect was investigated and led to the conclusion that wavelet transform is one of the best solutions available. Since watermarking is not an easy task, especially considering the robustness under various attacks several techniques were employed in order to increase the capacity/robustness of the system: spread-spectrum and modulation techniques to cast the watermark, powerful error correction to protect the mark, human visual models to insert a robust mark and to ensure its invisibility. The combination of these methods led to a major improvement, but yet the system wasn't robust to several important geometrical attacks. In order to achieve this last milestone, the system uses two distinct watermarks: a spatial domain reference watermark and the main watermark embedded in the wavelet domain. By using this reference watermark and techniques specific to image registration, the system is able to determine the parameters of the attack and revert it. Once the attack was reverted, the main watermark is recovered. The final result is a high capacity, blind DWr-based video watermarking system, robust to a wide range of attacks.BBC Research & Developmen

Prediction Of Pressure Coefficients For Flat Lip Vertical Gates

The main function of dam structures is to regulate the discharges and heads of water required to satisfy the demand of power generation and water quantity supplied to river or stream behind the structure, hence the sluice gate will play the big role to achieve this process and then its design needs much more attention. The sluice gate within the tunnel of the dam is exposed to many types of static and hydrodynamic forces .Among these forces is the hydraulic downpull force which created from difference between downward force produced by flow passing over the top surface of gate and uplift force exerted by the jet flow on bottom gate surface . The evaluation of positive and / or negative downpull force values is important due to its effects on closure of the gate. The estimation of such force needs determination of many related parameters such as pressure distribution along and cross the bottom gate surface, top pressure ,jet velocity issuing below the gate ,operation head and the head downstream the gate shaft. In present research, the hydraulic model is used to carry out the required measurements and different types of gate lip shapes have been examined with various flow conditions and gate openings to evaluate the downpull force coefficient. The analysis of results assured that the geometry of the lip gate has significant effects on the hydrodynamics forces and consequently on its operation which in the case of its negative value will prevent the gate to close and make some failures and damages

Prediction of Time-Dependent Deflection of High Strength Concrete Panels

This work presents a model for predicting analytically the time dependent deflection of high strength concrete HSC slabs. This model considers the factors that are significantly influence the long-term deflection of concrete slabs. Realising the effect of time on slab flexural rigidity, the proposed method follow the method of conducting short-term deflection of slabs.The analytical deflection based on the proposed method are compared with the experimental work conducted by the authors in 2005 (1) and also with several field measured deflections

RESIDENTIAL BUILDING DEVELOPMENT PROCESS IN KURDISTAN REGION GOVERNMENT

Nowadays, Residential buildings have become the most important part of real-estate markets in (KRG). The layout of housing in Kurdistan has transformed the face of major cities across the Region. Rapid changes since 2003, have witnessed copious architectural structures and large housing projects that have reshaped the landscape of its cities. The aim of this study is to study the housing developing policy in KRG. The objectives of the study are to evaluate the KRG's housing development policy and to investigate the types of house and the price range preferred by the potential buyer. The study focus on private residential building development projects and it is carried out by questionnaires and interviews. The respondents are the house buyers and the developers. A total of 100 questionnaires were distributed to the respondents and 78 questionnaires were returned duly answered. The data collected is analyzed using the SPSS (Statistical Package for the Social Sciences) and Average Index. The results of research indicated that the KRG’s housing development policy covers the ownership of the project land, full repatriation of project investment and profits allowed, import of spare parts tax exempt up to 15% of project cost and the employment of foreign workers allowed. Moreover, the types of house preferred by the house buyers are of double storey type and to be of corner lot. The price range preferred by the potential buyers are between (40,000 to 100,000) USD

Erbil Citadel Landscape Assessment In Order To Regional Best Practices

Many heritage areas around the world are suffered from neglect in maintenance or rehabilitation, and never consider their historical values as an attraction places for visitors, in addition to these problems a lot of ancient buildings were removed in different old cities and a new modern constructions were shown instead of traditional ones, and that leads to visual and structural distortion and thus a problem in tourism. The area surrounding the citadel of Erbil suffered from many of these troubles, thus we have to focus on them, and present suggestions to solve the problems by presenting a world successful experience in this fiel

Sustainability In Construction Projects: Part 2 (Case Studies)

The guideline developed in a companion study by the authors is applied and studied in this work to assess the sustainability score of several big construction projects in Kurdistan Region of Iraq. Results were varied as the sustainability measures being applied on certain steps and neglected on many others .Attention on this issue can be found in the conclusions