FPAA based desıgn and implementation of sprott N chaotic system

Nowadays, chaotic systems are used in various studies of different disciplines. Today, chaotic systems are used in various studies of different disciplines. In the literature, chaotic systems with various features have been introduced up to the present. In order to use these new chaotic systems in real-world engineering applications such as encryption, secure communication and authentication, they must be realized besides numerical simulations. In the literature, analog chaotic system implementations have been realized mainly with OPAMP devices. FPGAs and microcontrollers are used mostly in digital designs of chaotic systems. In this study, FPAA (Field Programmable Analog Array) based design and realization of Sprott N chaotic system was carried out. FPAA based design and numerical simulation results confirmed each other. As a result, it has been shown that the Sprott N chaotic system can be used based on FPAA in various engineering applications.Nowadays, chaotic systems are used in various studies of different disciplines. Today, chaotic systems are used in various studies of different disciplines. In the literature, chaotic systems with various features have been introduced up to the present. In order to use these new chaotic systems in real-world engineering applications such as encryption, secure communication and authentication, they must be realized besides numerical simulations. In the literature, analog chaotic system implementations have been realized mainly with OPAMP devices. FPGAs and microcontrollers are used mostly in digital designs of chaotic systems. In this study, FPAA (Field Programmable Analog Array) based design and realization of Sprott N chaotic system was carried out. FPAA based design and numerical simulation results confirmed each other. As a result, it has been shown that the Sprott N chaotic system can be used based on FPAA in various engineering applications

High-speed imaging with optical encoding and compressive sensing

Imaging instruments can be used to obtain a series of frames in domains such as frequency and time. Recent advancements in applications such as medical astronomical, scientic and the consumer application, demand overall improvements in these imaging systems. Many current imaging methods rely on the well-known Shannon-Nyquist theorem where sustaining this conventional model increases the system complexity, data rate, storage and processing power as well as the overall build costs of these units. Recent investigations based on the mathematical theory of compressed sensing (CS) have broken the traditional sampling mechanisms and introduces alternative methods of data sampling. This dissertation investigates the current advancements in the high-speed imaging schemes and proposes new methods and optical designs to improve the spatial and temporal resolution as well as the required transmission and storage capacity of the imaging systems. First, we investigate the current mathematical models of CS based algorithms in video acquisition systems and propose an improved adapted technique for data reconstruction. Then we investigate the state-of-the-art high-speed imaging methods and introduce optical encoding techniques that enable the current high-speed imaging systems to reach 10 times faster frame rates whilst preserving the spatial resolution of the existing systems. Second, we develop a novel high-speed imaging system that implements CS based optical imaging technique and experimentally demonstrate the operation of this novel imaging system. The proposed compressive coded rotating mirror (CCRM) camera benefits from noticeably improved physical dimensions, highly reduced build costs and the significantly simplified operation compared to the other high-speed cameras. Due to the built-in optical encoding and on-the-fly compression functionalities of CCRM camera, it becomes a viable option for the fields such as the medical and military based imaging applications where the security of the data remains one of the top priorities in the imaging instruments. Finally, we discuss the potential improvements on the CCRM camera and propose several advancement plans for the future of this system

Authentication enhancement in command and control networks: (a study in Vehicular Ad-Hoc Networks)

Intelligent transportation systems contribute to improved traffic safety by facilitating real time communication between vehicles. By using wireless channels for communication, vehicular networks are susceptible to a wide range of attacks, such as impersonation, modification, and replay. In this context, securing data exchange between intercommunicating terminals, e.g., vehicle-to-everything (V2X) communication, constitutes a technological challenge that needs to be addressed. Hence, message authentication is crucial to safeguard vehicular ad-hoc networks (VANETs) from malicious attacks. The current state-of-the-art for authentication in VANETs relies on conventional cryptographic primitives, introducing significant computation and communication overheads. In this challenging scenario, physical (PHY)-layer authentication has gained popularity, which involves leveraging the inherent characteristics of wireless channels and the hardware imperfections to discriminate between wireless devices. However, PHY-layerbased authentication cannot be an alternative to crypto-based methods as the initial legitimacy detection must be conducted using cryptographic methods to extract the communicating terminal secret features. Nevertheless, it can be a promising complementary solution for the reauthentication problem in VANETs, introducing what is known as “cross-layer authentication.” This thesis focuses on designing efficient cross-layer authentication schemes for VANETs, reducing the communication and computation overheads associated with transmitting and verifying a crypto-based signature for each transmission. The following provides an overview of the proposed methodologies employed in various contributions presented in this thesis. 1. The first cross-layer authentication scheme: A four-step process represents this approach: initial crypto-based authentication, shared key extraction, re-authentication via a PHY challenge-response algorithm, and adaptive adjustments based on channel conditions. Simulation results validate its efficacy, especially in low signal-to-noise ratio (SNR) scenarios while proving its resilience against active and passive attacks. 2. The second cross-layer authentication scheme: Leveraging the spatially and temporally correlated wireless channel features, this scheme extracts high entropy shared keys that can be used to create dynamic PHY-layer signatures for authentication. A 3-Dimensional (3D) scattering Doppler emulator is designed to investigate the scheme’s performance at different speeds of a moving vehicle and SNRs. Theoretical and hardware implementation analyses prove the scheme’s capability to support high detection probability for an acceptable false alarm value ≤ 0.1 at SNR ≥ 0 dB and speed ≤ 45 m/s. 3. The third proposal: Reconfigurable intelligent surfaces (RIS) integration for improved authentication: Focusing on enhancing PHY-layer re-authentication, this proposal explores integrating RIS technology to improve SNR directed at designated vehicles. Theoretical analysis and practical implementation of the proposed scheme are conducted using a 1-bit RIS, consisting of 64 × 64 reflective units. Experimental results show a significant improvement in the Pd, increasing from 0.82 to 0.96 at SNR = − 6 dB for multicarrier communications. 4. The fourth proposal: RIS-enhanced vehicular communication security: Tailored for challenging SNR in non-line-of-sight (NLoS) scenarios, this proposal optimises key extraction and defends against denial-of-service (DoS) attacks through selective signal strengthening. Hardware implementation studies prove its effectiveness, showcasing improved key extraction performance and resilience against potential threats. 5. The fifth cross-layer authentication scheme: Integrating PKI-based initial legitimacy detection and blockchain-based reconciliation techniques, this scheme ensures secure data exchange. Rigorous security analyses and performance evaluations using network simulators and computation metrics showcase its effectiveness, ensuring its resistance against common attacks and time efficiency in message verification. 6. The final proposal: Group key distribution: Employing smart contract-based blockchain technology alongside PKI-based authentication, this proposal distributes group session keys securely. Its lightweight symmetric key cryptography-based method maintains privacy in VANETs, validated via Ethereum’s main network (MainNet) and comprehensive computation and communication evaluations. The analysis shows that the proposed methods yield a noteworthy reduction, approximately ranging from 70% to 99%, in both computation and communication overheads, as compared to the conventional approaches. This reduction pertains to the verification and transmission of 1000 messages in total

18th IEEE Workshop on Nonlinear Dynamics of Electronic Systems: Proceedings

Proceedings of the 18th IEEE Workshop on Nonlinear Dynamics of Electronic Systems, which took place in Dresden, Germany, 26 – 28 May 2010.:Welcome Address ........................ Page I Table of Contents ........................ Page III Symposium Committees .............. Page IV Special Thanks ............................. Page V Conference program (incl. page numbers of papers) ................... Page VI Conference papers Invited talks ................................ Page 1 Regular Papers ........................... Page 14 Wednesday, May 26th, 2010 ......... Page 15 Thursday, May 27th, 2010 .......... Page 110 Friday, May 28th, 2010 ............... Page 210 Author index ............................... Page XII

Leveraging contextual-cognitive relationships into mobile commerce systems

A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophyMobile smart devices are becoming increasingly important within the on-line purchasing cycle. Thus the requirement for mobile commerce systems to become truly context-aware remains paramount if they are to be effective within the varied situations that mobile users encounter. Where traditionally a recommender system will focus upon the user – item relationship, i.e. what to recommend, in this thesis it is proposed that due to the complexity of mobile user situational profiles the how and when must also be considered for recommendations to be effective. Though non-trivial, it should be, through the understanding of a user’s ability to complete certain cognitive processes, possible to determine the likelihood of engagement and therefore the success of the recommendation. This research undertakes an investigation into physical and modal contexts and presents findings as to their relationships with cognitive processes. Through the introduction of the novel concept, disruptive contexts, situational contexts, including noise, distractions and user activity, are identified as having significant effects upon the relationship between user affective state and cognitive capability. Experimental results demonstrate that by understanding specific cognitive capabilities, e.g. a user’s perception of advert content and user levels of purchase-decision involvement, a system can determine potential user engagement and therefore improve the effectiveness of recommender systems’ performance. A quantitative approach is followed with a reliance upon statistical measures to inform the development, and subsequent validation, of a contextual-cognitive model that was implemented as part of a context-aware system. The development of SiDISense (Situational Decision Involvement Sensing system) demonstrated, through the use of smart-phone sensors and machine learning, that is was viable to classify subjectively rated contexts to then infer levels of cognitive capability and therefore likelihood of positive user engagement. Through this success in furthering the understanding of contextual-cognitive relationships there are novel and significant advances that are now viable within the area of m-commerce

A Poetics of Chaos: Schizoanalysis and Post modern American Fiction.

In "A Poetics of Chaos: Schizoanalysis and Postmodern American Fiction," I use theories from physics and psychoanalysis together to explore narrative structures in recent American fiction. Chaos theory, which emerged in mathematical and biological discourses in the 1960s, postulates the intrinsic instability and unpredictability of many natural and physical phenomena. Theorists like Bertalanffy, Mandelbrot and Lorenz produced a vocabulary to account for these pervasive systems. In assessing historical, economic and, indeed, literary systems, we may draw terms from chaotic inquiry: bifurcation, fractal, moebial, reiteration, complexity, butterfly effect, strange attractors, and sensitive dependence upon initial conditions. '"Chaotic narratives*" may explicitly deploy (Barth, Pynchon, Gibson) or inadvertently express (Coover, Ondaatje, Powers) the structural features of chaotic systems. Such writing is characterized by a diffusion of linear chronology, as well as ontological and narrative fracture, repetition and variation. Literary theorists N. Katherine Hayles, Joseph Conte, Hanjo Berressem and others have discussed how chaotic scientific and psycho-social systems are not only invoked in contemporary literature, but are themselves the structural and philosophical underpinnings of postmodern culture. My thesis builds upon chaotic-literary criticism by investigating the psychological implications of "chaotic narratives." Drawing from the anti-deterministic "schizoanalysis" of Gilles Deleuze and Felix Guattari, I explain how writings by Don DeLillo, Paul Auster, David Foster Wallace and Mark Z. Danielewski perform and reflect the "orderly disorder" of psychic development. I advance the term "psychochaotics*' to describe a theoretical approach that uses principles from chaos theory to reveal the psychodynamic systems in postmodern fiction

Nonlinear Dynamics of Semiconductor Lasers and Their Applications

Semiconductor lasers are key components in many optical systems due to their advantages, including their small size, low cost, high efficiency, and low power consumption. It is well-known that semiconductor lasers under external perturbations, such as optical injection, optical feedback, or delayed coupling can exhibit a large variety of complex dynamical behaviors. Nowadays, cutting-edge engineering applications based on the complex dynamics of diode lasers are being conducted in areas, such as optical communications, optical signal processing, encoded communications, neuro-inspired ultra-fast optical computing devices, microwave signal generation, RADAR and LIDAR applications, biomedical imaging, and broadband spectroscopy. The prospects for these applications are even more exciting with the advent of photonic integrated circuits. This Special Issue focuses on theoretical and experimental advances in the nonlinear dynamics of semiconductor lasers subject to different types of external perturbations

Distant Operational Care Centre: Design Project Report

The goal of this project is to outline the design of the Distant Operational Care Centre (DOCC), a modular medical facility to maintain human health and performance in space, that is adaptable to a range of remote human habitats. The purpose of this project is to outline a design, not to go into a complete technical specification of a medical facility for space. This project involves a process to produce a concise set of requirements, addressing the fundamental problems and issues regarding all aspects of a space medical facility for the future. The ideas presented here are at a high level, based on existing, researched, and hypothetical technologies. Given the long development times for space exploration, the outlined concepts from this project embodies a collection of identified problems, and corresponding proposed solutions and ideas, ready to contribute to future space exploration efforts. In order to provide a solid extrapolation and speculation in the context of the future of space medicine, the extent of this project's vision is roughly within the next two decades. The Distant Operational Care Centre (DOCC) is a modular medical facility for space. That is, its function is to maintain human health and performance in space environments, through prevention, diagnosis, and treatment. Furthermore, the DOCC must be adaptable to meet the environmental requirements of different remote human habitats, and support a high quality of human performance. To meet a diverse range of remote human habitats, the DOCC concentrates on a core medical capability that can then be adapted. Adaptation would make use of the DOCC's functional modularity, providing the ability to replace, add, and modify core functions of the DOCC by updating hardware, operations, and procedures. Some of the challenges to be addressed by this project include what constitutes the core medical capability in terms of hardware, operations, and procedures, and how DOCC can be adapted to different remote habitats

Harnessing Simulated Data with Graphs

Physically accurate simulations allow for unlimited exploration of arbitrarily crafted environments. From a scientific perspective, digital representations of the real world are useful because they make it easy validate ideas. Virtual sandboxes allow observations to be collected at-will, without intricate setting up for measurements or needing to wait on the manufacturing, shipping, and assembly of physical resources. Simulation techniques can also be utilized over and over again to test the problem without expending costly materials or producing any waste. Remarkably, this freedom to both experiment and generate data becomes even more powerful when considering the rising adoption of data-driven techniques across engineering disciplines. These are systems that aggregate over available samples to model behavior, and thus are better informed when exposed to more data. Naturally, the ability to synthesize limitless data promises to make approaches that benefit from datasets all the more robust and desirable. However, the ability to readily and endlessly produce synthetic examples also introduces several new challenges. Data must be collected in an adaptive format that can capture the complete diversity of states achievable in arbitrary simulated configurations while too remaining amenable to downstream applications. The quantity and zoology of observations must also straddle a range which prevents overfitting but is descriptive enough to produce a robust approach. Pipelines that naively measure virtual scenarios can easily be overwhelmed by trying to sample an infinite set of available configurations. Variations observed across multiple dimensions can quickly lead to a daunting expansion of states, all of which must be processed and solved. These and several other concerns must first be addressed in order to safely leverage the potential of boundless simulated data. In response to these challenges, this thesis proposes to wield graphs in order to instill structure over digitally captured data, and curb the growth of variables. The paradigm of pairing data with graphs introduced in this dissertation serves to enforce consistency, localize operators, and crucially factor out any combinatorial explosion of states. Results demonstrate the effectiveness of this methodology in three distinct areas, each individually offering unique challenges and practical constraints, and together showcasing the generality of the approach. Namely, studies observing state-of-the-art contributions in design for additive manufacturing, side-channel security threats, and large-scale physics based contact simulations are collectively achieved by harnessing simulated datasets with graph algorithms