1,589 research outputs found

    Efficient and Secure Chaotic S-Box for Wireless Sensor Network

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    International audienceInformation security using chaotic dynamics is a novel topic in the wireless sensor network (WSN) research field. After surveying analog and digital chaotic security systems, we give a state of the art of chaotic S-Box design. The substitution tables are nonlinear maps that strengthen and enhance block crypto-systems. This paper deals with the design of new dynamic chaotic S-Boxes suitable for implementation on wireless sensor nodes. Our proposed schemes are classified into two categories: S-Box based on discrete chaotic map with floating point arithmetic (cascading piecewise linear chaotic map and a three-dimensional map) and S-Box based on discrete chaotic map with fixed-point arithmetic (using discretized Lorenz map and logistic–tent map). The security analysis and implementation process on WSN are discussed. The proposed methods satisfy Good S-Box design criteria and exceed the performance of Advanced Encryption Standard static S-Box in some cases. The energy consumption of different proposals and existing chaotic S-Box designs are investigated via a platform simulator and a real WSN testbed equipped with TI MSP430f1611 micro-controller. The simulations and the experimental results show that our proposed S-Box design with fixed-point arithmetic Lorenz map has the lowest energy-consuming profile compared with the other studied and proposed S-Box design

    Research on digital image watermark encryption based on hyperchaos

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    The digital watermarking technique embeds meaningful information into one or more watermark images hidden in one image, in which it is known as a secret carrier. It is difficult for a hacker to extract or remove any hidden watermark from an image, and especially to crack so called digital watermark. The combination of digital watermarking technique and traditional image encryption technique is able to greatly improve anti-hacking capability, which suggests it is a good method for keeping the integrity of the original image. The research works contained in this thesis include: (1)A literature review the hyperchaotic watermarking technique is relatively more advantageous, and becomes the main subject in this programme. (2)The theoretical foundation of watermarking technologies, including the human visual system (HVS), the colour space transform, discrete wavelet transform (DWT), the main watermark embedding algorithms, and the mainstream methods for improving watermark robustness and for evaluating watermark embedding performance. (3) The devised hyperchaotic scrambling technique it has been applied to colour image watermark that helps to improve the image encryption and anti-cracking capabilities. The experiments in this research prove the robustness and some other advantages of the invented technique. This thesis focuses on combining the chaotic scrambling and wavelet watermark embedding to achieve a hyperchaotic digital watermark to encrypt digital products, with the human visual system (HVS) and other factors taken into account. This research is of significant importance and has industrial application value

    Dynamical Analysis of Terahertz Quantum Cascade Lasers

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    This thesis focuses on various aspects in terahertz quantum cascade lasers such as high temperature performances, electrical instabilities and chaos. In the first part of the thesis, an introduction to the topic and the non equilibrium Green's function package applied is given with particular emphasise on the inhomogeneous domain model and the chaos theory. In addition, new results regarding the high temperature operation of low frequency terahertz quantum cascade lasers are presented. In the second part, the related research articles are shown. Paper I shows numerical simulations demonstrating the first autonomous terahertz quantum cascade laser exhibiting chaos. Paper II provides a detailed analysis of the current record-holding terahertz quantum cascade lasers operating around 4 terahertz. A new design is suggested which should operates at an even higher temperature of 265 K.Paper III analyses the spectral behaviour of the output light generated by oscillating field domains in direct cooperation with the experiment. The overall behaviour is related to the phenomenological boundary conductivity and the external capacitance

    Projects and innovation : the ambiguity of the literature and its implications

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    The strategic role of new product development and innovation makes design performance a central concern of managers. Project management therefore appears to be an adequate solution to the integration problems raised by these activities. Work such as that of Clark et Fujimoto (1991) has helped make heavyweight project management a dominant organizational model. In this article, we wish to question this tendency to equate projects and innovation. This tendency can, in fact, appear surprising inasmuch as Clark et Fujimoto indicate that their research does not take into account the question of advanced engineering or basic research. We therefore believe that it can lead to improper use of the project format to manage innovation. We feel that, in line with work on project classification a distinction should be drawn between the various design situations to which different types of projects will be suited. Qualitative research conducted at a European automobile manufacturer on Telematics services will allow us to identify the management methods suited to the most innovative projects, i.e. those for which neither technologies nor customer requirements are known at the start of the project (referred to by Atkinson et al. (2006) as “soft” projects) We will show how these situations shake up traditional project management models and will propose five management principles adapted to this new situation.innovation;Management de projet;Services;TĂ©lĂ©matique automobile

    A survey of smart grid architectures, applications, benefits and standardization

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    The successful transformation of conventional power grids into Smart Grids (SG) will require robust and scalable communication network infrastructure. The SGs will facilitate bidirectional electricity flow, advanced load management, a self-healing protection mechanism and advanced monitoring capabilities to make the power system more energy efficient and reliable. In this paper SG communication network architectures, standardization efforts and details of potential SG applications are identified. The future deployment of real-time or near-real-time SG applications is dependent on the introduction of a SG compatible communication system that includes a communication protocol for cross-domain traffic flows within the SG. This paper identifies the challenges within the cross-functional domains of the power and communication systems that current research aims to overcome. The status of SG related machine to machine communication system design is described and recommendations are provided for diverse new and innovative traffic features

    Global Growth and Trends of In-Body Communication Research—Insight From Bibliometric Analysis

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    A bibliometric analysis was conducted to examine research on in-body communication. This study aimed to assess the research growth in different countries, identify influential authors for potential international collaboration, investigate research challenges, and explore future prospects for in-body communication. A total of 148 articles written in English from journals and conference proceedings were gathered from the Scopus database. These articles cover the period from 2006 until August 2023. VOS Viewer 1.6.19 and Tableau Cloud were used to analyze the data. The analysis reveals that research on in-body communication has shown fluctuations but overall tends to increase. The United States, Finland, and Japan were identified as the leading countries (top three) in terms of publication quantity, while researchers from Norway, Finland, and Morocco received the highest number of citations. The University of Oulu in Finland has emerged as a productive institution in this field. Collaborative research opportunities exist with the countries mentioned above or with authors who have expertise in this topic. The dominant research topic within this field pertains to ultra-wideband (UWB) technology. One of the future challenges in this field is the exploration of optical wireless communication (OWC) as a potential communication medium for in-body devices, such as electronic devices implanted in the human body. This includes improving performance to meet the requirements for in-body communication devices. Additionally, this paper provides further insights into the progress of research on OWC for in-body communication conducted in our laboratory

    Enhanced image encryption scheme with new mapreduce approach for big size images

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    Achieving a secured image encryption (IES) scheme for sensitive and confidential data communications, especially in a Hadoop environment is challenging. An accurate and secure cryptosystem for colour images requires the generation of intricate secret keys that protect the images from diverse attacks. To attain such a goal, this work proposed an improved shuffled confusion-diffusion based colour IES using a hyper-chaotic plain image. First, five different sequences of random numbers were generated. Then, two of the sequences were used to shuffle the image pixels and bits, while the remaining three were used to XOR the values of the image pixels. Performance of the developed IES was evaluated in terms of various measures such as key space size, correlation coefficient, entropy, mean squared error (MSE), peak signal to noise ratio (PSNR) and differential analysis. Values of correlation coefficient (0.000732), entropy (7.9997), PSNR (7.61), and MSE (11258) were determined to be better (against various attacks) compared to current existing techniques. The IES developed in this study was found to have outperformed other comparable cryptosystems. It is thus asserted that the developed IES can be advantageous for encrypting big data sets on parallel machines. Additionally, the developed IES was also implemented on a Hadoop environment using MapReduce to evaluate its performance against known attacks. In this process, the given image was first divided and characterized in a key-value format. Next, the Map function was invoked for every key-value pair by implementing a mapper. The Map function was used to process data splits, represented in the form of key-value pairs in parallel modes without any communication between other map processes. The Map function processed a series of key/value pairs and subsequently generated zero or more key/value pairs. Furthermore, the Map function also divided the input image into partitions before generating the secret key and XOR matrix. The secret key and XOR matrix were exploited to encrypt the image. The Reduce function merged the resultant images from the Map tasks in producing the final image. Furthermore, the value of PSNR did not exceed 7.61 when the developed IES was evaluated against known attacks for both the standard dataset and big data size images. As can be seen, the correlation coefficient value of the developed IES did not exceed 0.000732. As the handling of big data size images is different from that of standard data size images, findings of this study suggest that the developed IES could be most beneficial for big data and big size images

    AN ADAPTIVE INFORMATION DISSEMINATION MODEL FOR VANET COMMUNICATION

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    Vehicular ad hoc networks (VANETs) have been envisioned to be useful in road safety and many commercial applications. The growing trend to provide communication among the vehicles on the road has provided the opportunities for developing a variety of applications for VANET. The unique characteristics of VANET bring about new research challenges

    Reframing cognition:Getting down to biological basics

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    The premise of this two-part theme issue is simple: the cognitive sciences should join the rest of the life sciences in how they approach the quarry within their research domain. Specifically, understanding how organisms on the lower branches of the phylogenetic tree become familiar with, value and exploit elements of an ecological niche while avoiding harm can be expected to aid understanding of how organisms that evolved later (including Homo sapiens) do the same or similar things. We call this approach basal cognition. In this introductory essay, we explain what the approach involves. Because no definition of cognition exists that reflects its biological basis, we advance a working definition that can be operationalized; introduce a behaviour-generating toolkit of capacities that comprise the function (e.g. sensing/perception, memory, valence, learning, decision making, communication), each element of which can be studied relatively independently; and identify a (necessarily incomplete) suite of common biophysical mechanisms found throughout the domains of life involved in implementing the toolkit. The articles in this collection illuminate different aspects of basal cognition across different forms of biological organization, from prokaryotes and single-celled eukaryotes—the focus of Part 1—to plants and finally to animals, without and with nervous systems, the focus of Part 2. By showcasing work in diverse, currently disconnected fields, we hope to sketch the outline of a new multidisciplinary approach for comprehending cognition, arguably the most fascinating and hard-to-fathom evolved function on this planet. Doing so has the potential to shed light on problems in a wide variety of research domains, including microbiology, immunology, zoology, biophysics, botany, developmental biology, neurobiology/science, regenerative medicine, computational biology, artificial life and synthetic bioengineering
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