Academic literature on the topic 'Magnetic memory (Computers)'
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Journal articles on the topic "Magnetic memory (Computers)"
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Carley, L. Richard, James A. Bain, Gary K. Fedder, et al. "Single-chip computers with microelectromechanical systems-based magnetic memory (invited)." Journal of Applied Physics 87, no. 9 (2000): 6680–85. http://dx.doi.org/10.1063/1.372807.
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Md Rakibul Karim Akanda, D’Mytri Wiggs, and Nathaniel Zepeda. "Calculating magnetic properties of two-dimensional materials for memory applications." International Journal of Science and Research Archive 11, no. 1 (2024): 613–26. http://dx.doi.org/10.30574/ijsra.2024.11.1.0098.
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Calculating magnetic properties of two-dimensional materials is crucial for implementing memory devices (like USB drive, RAM, hard disk drive of computers) having reduced size. Two dimensional materials can be implemented as a thin film which can reduce the size of memory devices. These materials as well as devices made with magnetic two-dimensional materials are of current research interest in industry and academia. From the materials project database, crystal structure file of 30 two dimensional materials have been downloaded to calculate their magnetic properties. BURAI Quantum espresso software has been used to extract magnetic properties of 30 two dimensional (2D) materials. These 30 materials have magnetic Fe, Ni, Co, Mn, and Cr atoms in their molecular structure. Magnetic materials play a key and vital role in today’s modern-day technology. There are five different types of magnetic materials. The classification magnetic materials are diamagnetism, paramagnetic, ferromagnetism, ferrimagnetism, and anti-ferromagnetism. Total energy of different magnetic configurations has been calculated to find the most stable magnetic configurations of these materials.
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Ou, Qiao-Feng, Bang-Shu Xiong, Lei Yu, Jing Wen, Lei Wang, and Yi Tong. "In-Memory Logic Operations and Neuromorphic Computing in Non-Volatile Random Access Memory." Materials 13, no. 16 (2020): 3532. http://dx.doi.org/10.3390/ma13163532.
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Recent progress in the development of artificial intelligence technologies, aided by deep learning algorithms, has led to an unprecedented revolution in neuromorphic circuits, bringing us ever closer to brain-like computers. However, the vast majority of advanced algorithms still have to run on conventional computers. Thus, their capacities are limited by what is known as the von-Neumann bottleneck, where the central processing unit for data computation and the main memory for data storage are separated. Emerging forms of non-volatile random access memory, such as ferroelectric random access memory, phase-change random access memory, magnetic random access memory, and resistive random access memory, are widely considered to offer the best prospect of circumventing the von-Neumann bottleneck. This is due to their ability to merge storage and computational operations, such as Boolean logic. This paper reviews the most common kinds of non-volatile random access memory and their physical principles, together with their relative pros and cons when compared with conventional CMOS-based circuits (Complementary Metal Oxide Semiconductor). Their potential application to Boolean logic computation is then considered in terms of their working mechanism, circuit design and performance metrics. The paper concludes by envisaging the prospects offered by non-volatile devices for future brain-inspired and neuromorphic computation.
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McKemmish, Laura K., David J. Kedziora, Graham R. White, Noel S. Hush, and Jeffrey R. Reimers. "Frequency-based Quantum Computers from a Chemist's Perspective." Australian Journal of Chemistry 65, no. 5 (2012): 512. http://dx.doi.org/10.1071/ch12053.
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Quantum computer elements are often designed and tested using molecular or nanoscopic components that form registers of qubits in which memory is stored and information processed. Often such registers are probed and manipulated using frequency-based techniques such as nuclear-magnetic resonance spectroscopy. A major challenge is to design molecules to act as these registers. We provide a basis for rational molecular design through consideration of the generic spectroscopic properties required for quantum computing, bypassing the need for intricate knowledge of the way these molecules are used spectroscopically. Designs in which two-qubit gate times scale similarly to those for one-qubit gates are presented. The specified spectroscopic requirements are largely independent of the type of spectroscopy used (e.g. magnetic resonance or vibrational) and are often independent of technical details of the application (e.g. broadband or high-resolution spectroscopy). This should allow the design of much larger quantum registers than have currently been demonstrated.
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Wang, Frank Zhigang. "Beyond Memristors: Neuromorphic Computing Using Meminductors." Micromachines 14, no. 2 (2023): 486. http://dx.doi.org/10.3390/mi14020486.
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Resistors with memory (memristors), inductors with memory (meminductors) and capacitors with memory (memcapacitors) play different roles in novel computing architectures. We found that a coil with a magnetic core is an inductor with memory (meminductor) in terms of its inductance L(q) being a function of charge q. The history of the current passing through the coil is remembered by the magnetization inside the magnetic core. Such a meminductor can play a unique role (that cannot be played by a memristor) in neuromorphic computing, deep learning and brain-inspired computers since the time constant (t0=LC) of a neuromorphic RLC circuit is jointly determined by the inductance L and capacitance C, rather than the resistance R. As an experimental verification, this newly invented meminductor was used to reproduce the observed biological behavior of amoebae (the memorizing, timing and anticipating mechanisms). In conclusion, a beyond-memristor computing paradigm is theoretically sensible and experimentally practical.
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Donahue, M. J. "Parallelizing a Micromagnetic Program for Use on Multiprocessor Shared Memory Computers." IEEE Transactions on Magnetics 45, no. 10 (2009): 3923–25. http://dx.doi.org/10.1109/tmag.2009.2023866.
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Murray, Keith S. "Recent Advances in Molecular Magnetic Materials." Australian Journal of Chemistry 62, no. 9 (2009): 1081. http://dx.doi.org/10.1071/ch09260.
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This review describes advances made in three areas of molecular magnetic materials of the types A: extended frameworks (coordination polymers) showing long-range magnetic order, B: spin-coupled clusters with emphasis on single molecule magnets and (n × n) grid species, C: polynuclear spin-switching (spin crossover) compounds of FeII with emphasis on dinuclear compounds and one-dimensional (1D) and three-dimensional (3D) (framework) materials, including porous ‘hybrid’ systems. The work of the author and his group is largely used to provide examples, together with results from other groups and collaborators that are included for comparison and completeness. Supramolecular aspects such as cluster–cluster and chain–chain interactions are discussed where relevant. A brief discussion is also given of the recent studies, carried out elsewhere, dealing with aspects of spintronics and the possible future relevance to molecular computers (type B materials) and with memory and other device possibilities (type C materials)
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Simoni, Mario, Giovanni Amedeo Cirillo, Giovanna Turvani, Mariagrazia Graziano, and Maurizio Zamboni. "Towards Compact Modeling of Noisy Quantum Computers: A Molecular-Spin-Qubit Case of Study." ACM Journal on Emerging Technologies in Computing Systems 18, no. 1 (2022): 1–26. http://dx.doi.org/10.1145/3474223.
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Classical simulation of Noisy Intermediate Scale Quantum computers is a crucial task for testing the expected performance of real hardware. The standard approach, based on solving Schrödinger and Lindblad equations, is demanding when scaling the number of qubits in terms of both execution time and memory. In this article, attempts in defining compact models for the simulation of quantum hardware are proposed, ensuring results close to those obtained with standard formalism. Molecular Nuclear Magnetic Resonance quantum hardware is the target technology, where three non-ideality phenomena—common to other quantum technologies—are taken into account: decoherence, off-resonance qubit evolution, and undesired qubit-qubit residual interaction. A model for each non-ideality phenomenon is embedded into a MATLAB simulation infrastructure of noisy quantum computers. The accuracy of the models is tested on a benchmark of quantum circuits, in the expected operating ranges of quantum hardware. The corresponding outcomes are compared with those obtained via numeric integration of the Schrödinger equation and the Qiskit’s QASMSimulator. The achieved results give evidence that this work is a step forward towards the definition of compact models able to provide fast results close to those obtained with the traditional physical simulation strategies, thus paving the way for their integration into a classical simulator of quantum computers.
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Hong, Jeongmin, Brian Lambson, Scott Dhuey, and Jeffrey Bokor. "Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bits." Science Advances 2, no. 3 (2016): e1501492. http://dx.doi.org/10.1126/sciadv.1501492.
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Minimizing energy dissipation has emerged as the key challenge in continuing to scale the performance of digital computers. The question of whether there exists a fundamental lower limit to the energy required for digital operations is therefore of great interest. A well-known theoretical result put forward by Landauer states that any irreversible single-bit operation on a physical memory element in contact with a heat bath at a temperature T requires at least kBT ln(2) of heat be dissipated from the memory into the environment, where kB is the Boltzmann constant. We report an experimental investigation of the intrinsic energy loss of an adiabatic single-bit reset operation using nanoscale magnetic memory bits, by far the most ubiquitous digital storage technology in use today. Through sensitive, high-precision magnetometry measurements, we observed that the amount of dissipated energy in this process is consistent (within 2 SDs of experimental uncertainty) with the Landauer limit. This result reinforces the connection between “information thermodynamics” and physical systems and also provides a foundation for the development of practical information processing technologies that approach the fundamental limit of energy dissipation. The significance of the result includes insightful direction for future development of information technology.
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Dahal, Bishnu R., Andrew Grizzle, Christopher D’Angelo, Vincent Lamberti, and Pawan Tyagi. "Competing Easy-Axis Anisotropies Impacting Magnetic Tunnel Junction-Based Molecular Spintronics Devices (MTJMSDs)." International Journal of Molecular Sciences 23, no. 22 (2022): 14476. http://dx.doi.org/10.3390/ijms232214476.
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Molecular spintronics devices (MSDs) attempt to harness molecules’ quantum state, size, and configurable attributes for application in computer devices—a quest that began more than 70 years ago. In the vast number of theoretical studies and limited experimental attempts, MSDs have been found to be suitable for application in memory devices and futuristic quantum computers. MSDs have recently also exhibited intriguing spin photovoltaic-like phenomena, signaling their potential application in cost-effective and novel solar cell technologies. The molecular spintronics field’s major challenge is the lack of mass-fabrication methods producing robust magnetic molecule connections with magnetic electrodes of different anisotropies. Another main challenge is the limitations of conventional theoretical methods for understanding experimental results and designing new devices. Magnetic tunnel junction-based molecular spintronics devices (MTJMSDs) are designed by covalently connecting paramagnetic molecules across an insulating tunneling barrier. The insulating tunneling barrier serves as a mechanical spacer between two ferromagnetic (FM) electrodes of tailorable magnetic anisotropies to allow molecules to undergo many intriguing phenomena. Our experimental studies showed that the paramagnetic molecules could produce strong antiferromagnetic coupling between two FM electrodes, leading to a dramatic large-scale impact on the magnetic electrode itself. Recently, we showed that the Monte Carlo Simulation (MCS) was effective in providing plausible insights into the observation of unusual magnetic domains based on the role of single easy-axis magnetic anisotropy. Here, we experimentally show that the response of a paramagnetic molecule is dramatically different when connected to FM electrodes of different easy-axis anisotropies. Motivated by our experimental studies, here, we report on an MCS study investigating the impact of the simultaneous presence of two easy-axis anisotropies on MTJMSD equilibrium properties. In-plane easy-axis anisotropy produced multiple magnetic phases of opposite spins. The multiple magnetic phases vanished at higher thermal energy, but the MTJMSD still maintained a higher magnetic moment because of anisotropy. The out-of-plane easy-axis anisotropy caused a dominant magnetic phase in the FM electrode rather than multiple magnetic phases. The simultaneous application of equal-magnitude in-plane and out-of-plane easy-axis anisotropies on the same electrode negated the anisotropy effect. Our experimental and MCS study provides insights for designing and understanding new spintronics-based devices.
Dissertations / Theses on the topic "Magnetic memory (Computers)"
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Schiepp, Thomas. "A simulation method for design and development of magnetic shape memory actuators." Thesis, University of Gloucestershire, 2015. http://eprints.glos.ac.uk/2974/.
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The systems/products and their design processes have become more and more complicated due to the fact that their requirements in terms of function, durability, reliability and energy efficiency have been increased significantly and that their leading time has to be short and their materials cost has to be low. To meet these requirements, individual parts and subsystems have to offer increased functionality and efficiency themselves. It has been found that smart materials, such as piezo ceramics or various shape memory alloys as well as less known dielectric elastomers or magnetic shape memory alloys, offer ideal preconditions to fulfil such requirements. Among the various shape memory alloys, the Magnetic Shape Memory (MSM) alloy is a kind of smart material that can elongate and contract in a magnetic field. Based on the MSM alloy a new type of smart electromagnetic actuators have been designed and developed. This kind of actuator exhibits the features above. Typically, the MSM material is a monocrystalline Ni-Mn-Ga alloy, which has the ability to change its size or shape very fast and many million times repeatedly. State-of-the-art alloys are able to achieve a magnetic field induced strain of up to 12%. The magneto-mechanical characteristic of MSM alloys is being constantly improved. However, as far as the author is aware, there are no efficient and commercially available tools for engineers to design MSM-based actuators. To achieve this, simulation tools for design are indispensable. This thesis is dedicated to this task. In this PhD thesis, new design and simulation techniques for MSM-based actuators have been studied. In particular, three simulation methods have been proposed. These three methods extend standard magneto-static FEM simulation techniques by taking into account the magneto-mechanical coupling and the magnetic anisotropy of the MSM materials. They differ in terms of the necessary a priori alloy characterisation (i.e., measurement effort), computational complexity and consequent computing time. The magneto-mechanical characteristics of the MSM material are a necessary and fundamental ingredient for this type of simulation. However, the characterisation of the MSM materials is a very challenging task and requires specific modifications to standard measurement approaches. So, in this thesis, some specific measurement methods of the magneto-mechanical characteristics of the MSM materials have been proposed, designed and developed. It is described how existing measurement instruments can be modified to measure the unique magneto-mechanical characteristics of MSM, so they are applicable and with practical values. Various tests have been carried out to validate the new methods and the necessary characterisations of the properties of MSM materials have been performed, such as the measurement of the permeability of MSM under a defined stress during elongation. The new measurement results have been analysed and the findings have been used to design and develop the simulation methods. The three simulation methods can be used to predict and optimise the current-elongation behaviour of an MSM element under the load of a mechanical stress while excited by a magnetic field. Extensive experiments have been carried out to validate these three simulation methods. The results show that the three methods are relatively simple but, at the same time, very effective means to model, predict and optimise the properties of an MSM actuator using finite element tools. In addition, the experiment results have also shown that the simulation methods can be used to gain some deep insights into the magneto-mechanical interaction between the MSM element and the electromagnetic actuator. In this thesis an evolutionary algorithm which works together with the simulation methods has been developed to achieve individual optimised solutions in very short times. In summary, from the experiment results, it has been found that the measurements and simulation methods proposed and developed in this thesis; enable designers to perform simulations for a high-quality actuator design based on the magneto-mechanical properties of MSM alloys. This is the first time that a MSM can be characterised for simulation purposes in a fast and precise way to predict MSM and electromagnetic actuator interactions and identify and optimise the design parameters of such actuators. However, these simulation methods are strongly dependent on the measurement of the magneto-mechanical characteristics of magnetic shape memory alloys, whose precision can be further improved. To reach commercial success as well higher precision in the simulation prediction, further achievements in the field of material science (e.g. smoothness of mechanical curves) are also necessary.
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Blum, Daniel Ryan. "Hardened by design approaches for mitigating transient faults in memory-based systems." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Spring2007/d_blum_043007.pdf.
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Obi, Manasseh Okocha. "Materials consideration for nanoionic nonvolatile memory solutions." [Boise, Idaho] : Boise State University, 2009. http://scholarworks.boisestate.edu/td/50/.
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Griffiths, R. B. "Virtual memory systems using magnetic bubble memory." Thesis, Bucks New University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356215.
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Muriithi, Paul Mutuanyingi. "A case for memory enhancement : ethical, social, legal, and policy implications for enhancing the memory." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/a-case-for-memory-enhancement-ethical-social-legal-and-policy-implications-for-enhancing-the-memory(bf11d09d-6326-49d2-8ef3-a40340471acf).html.
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The desire to enhance and make ourselves better is not a new one and it has continued to intrigue throughout the ages. Individuals have continued to seek ways to improve and enhance their well-being for example through nutrition, physical exercise, education and so on. Crucial to this improvement of their well-being is improving their ability to remember. Hence, people interested in improving their well-being, are often interested in memory as well. The rationale being that memory is crucial to our well-being. The desire to improve one’s memory then is almost certainly as old as the desire to improve one’s well-being. Traditionally, people have used different means in an attempt to enhance their memories: for example in learning through storytelling, studying, and apprenticeship. In remembering through practices like mnemonics, repetition, singing, and drumming. In retaining, storing and consolidating memories through nutrition and stimulants like coffee to help keep awake; and by external aids like notepads and computers. In forgetting through rituals and rites. Recent scientific advances in biotechnology, nanotechnology, molecular biology, neuroscience, and information technologies, present a wide variety of technologies to enhance many different aspects of human functioning. Thus, some commentators have identified human enhancement as central and one of the most fascinating subject in bioethics in the last two decades. Within, this period, most of the commentators have addressed the Ethical, Social, Legal and Policy (ESLP) issues in human enhancements as a whole as opposed to specific enhancements. However, this is problematic and recently various commentators have found this to be deficient and called for a contextualized case-by-case analysis to human enhancements for example genetic enhancement, moral enhancement, and in my case memory enhancement (ME). The rationale being that the reasons for accepting/rejecting a particular enhancement vary depending on the enhancement itself. Given this enormous variation, moral and legal generalizations about all enhancement processes and technologies are unwise and they should instead be evaluated individually. Taking this as a point of departure, this research will focus specifically on making a case for ME and in doing so assessing the ESLP implications arising from ME. My analysis will draw on the already existing literature for and against enhancement, especially in part two of this thesis; but it will be novel in providing a much more in-depth analysis of ME. From this perspective, I will contribute to the ME debate through two reviews that address the question how we enhance the memory, and through four original papers discussed in part three of this thesis, where I examine and evaluate critically specific ESLP issues that arise with the use of ME. In the conclusion, I will amalgamate all my contribution to the ME debate and suggest the future direction for the ME debate.
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Sandblom, Johan. "Episodic memory in the human prefrontal cortex /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-136-4/.
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Chen, Zhi. "Power-Efficient and Low-Latency Memory Access for CMP Systems with Heterogeneous Scratchpad On-Chip Memory." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/25.
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The gradually widening speed disparity of between CPU and memory has become an overwhelming bottleneck for the development of Chip Multiprocessor (CMP) systems. In addition, increasing penalties caused by frequent on-chip memory accesses have raised critical challenges in delivering high memory access performance with tight power and latency budgets. To overcome the daunting memory wall and energy wall issues, this thesis focuses on proposing a new heterogeneous scratchpad memory architecture which is configured from SRAM, MRAM, and Z-RAM. Based on this architecture, we propose two algorithms, a dynamic programming and a genetic algorithm, to perform data allocation to different memory units, therefore reducing memory access cost in terms of power consumption and latency. Extensive and intensive experiments are performed to show the merits of the heterogeneous scratchpad architecture over the traditional pure memory system and the effectiveness of the proposed algorithms.
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Govindaraj, Rekha. "Emerging Non-Volatile Memory Technologies for Computing and Security." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7674.
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With CMOS technology scaling reaching its limitations rigorous research of alternate and competent technologies is paramount to push the boundaries of computing. Spintronic and resistive memories have proven to be effective alternatives in terms of area, power and performance to CMOS because of their non-volatility, ability for logic computing and easy integration with CMOS. However, deeper investigations to understand their physical phenomenon and improve their properties such as writability, stability, reliability, endurance, uniformity with minimal device-device variations is necessary for deployment as memories in commercial applications. Application of these technologies beyond memory and logic are investigated in this thesis i.e. for security of integrated circuits and systems and special purpose memories. We proposed a spintonic based special purpose memory for search applications, present design analysis and techniques to improve the performance for larger word lengths upto 256 bits. Salient characteristics of RRAM is studied and exploited in the design of widely accepted hardware security primitives such as Physically Unclonable Function (PUF) and True Random Number Generators (TRNG). Vulnerability of these circuits to adversary attacks and countermeasures are proposed. Proposed PUF can be implemented within 1T-1R conventional memory architecture which offers area advantages compared to RRAM memory and cross bar array PUFs with huge number of challenge response pairs. Potential application of proposed strong arbiter PUF in the Internet of things is proposed and performance is evaluated theoretically with valid assumptions on the maturity of RRAM technology. Proposed TRNG effectively utilizes the random telegraph noise in RRAM current to generate random bit stream. TRNG is evaluated for sufficient randomness in the random bit stream generated. Vulnerability and countermeasures to adversary attacks are also studied. Finally, in thesis we investigated and extended the application of emerging non-volatile memory technologies for search and security in integrated circuits and systems.
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Ragnehed, Mattias. "Functional Magnetic Resonance Imaging for Clinical Diagnosis : Exploring and Improving the Examination Chain." Doctoral thesis, Linköping : Department of Medical and Health Sciences, Linköping University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18095.
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Li, Jing-Rebecca. "Modélisation et simulation de la diffusion." Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00925028.
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Deux concepts très importants dans mes travaux sont ceux de la diffusion (mouvement aléatoire des particules) et de ceux de la transformée de Fourier. La diffusion des particules peut être décrite par l'équation de la diffusion, dont la solution fondamentale a un forme beaucoup plus complexe que sa transformée de Fourier. Tout d'abord, nous profitons de la forme spéciale de la transformée de Fourier (dans l'espace) de la fonction de Green de l'équation de diffusion pour formuler des méthodes numériques qui sont locales en temps pour la solution des équations avec mémoire. L'idée principale est que la solution sera calculée dans le domaine de Fourier, pour éviter d'évaluer les intégrales de convolution en temps portent la " mémoire ". Ce travail a été rendu possible par le développement d'une quadrature adaptée de l'intégrale de Fourier où un petit nombre de points dans la variable de Fourier était suffisant pour une bonne résolution du problème dans l'espace physique, sur un intervalle de temps important. En particulier, nous avons développé une méthode numérique pour simuler la diffusion dans des domaines non bornés avec sources et l'avons appliquée à la modélisation de la croissance des cristaux, à l'aide du modèle du champ de phase. Puis, afin d'étendre cette approche à des problèmes aux limites, nous avons abordé la question de l'évaluation des potentiels de simple couche et de double couche sur le bord du domaine. Enfin, nous avons généralisé l'idée de remplacer les intégrales de convolution en temps par une quadrature efficace dans le domaine de Fourier, aux intégrales et aux dérivés d'ordres fractionnaires, et obtenu une borne rigoureuse de l'erreur de quadrature. Nous avons aussi appliqué cette approche à une équation des ondes fractionnaire. En 2010, j'ai commencé à appliquer les outils numériques et analytiques à l'équation de Bloch-Torrey, dans le domaine de l'imagerie par résonance magnétique de la diffusion (IRMd) du cerveau. Ce travail a commencé dans le cadre d'une collaboration avec des physiciens d'IRM de Neurospin. Nous avons essayé d'expliquer la relation entre la géométrie cellulaire, la perméabilité membranaire et le signal d'IRMd obtenu. Certaines difficultés de la modélisation et de la simulation du signal d'IRMd au niveau de l'échelle de temps et de l'espace viennent de la physique et de la biologie d'IRMd du cerveau. Premièrement, pour des raisons biologiques et techniques, l'IRMd ne peut mesurer que des temps de diffusion compris entre une et cent millisecondes, correspondant à une distance de diffusion moyenne de 2,5 à 25 micromètres. Cette distance est moyennée sur toutes les molécules d'eau, et la distance de diffusion réelle peut être différente selon que la localisation, au début de la mesure, des molécules d'eau : dans les corps neuronaux, dans les neurites (dendrites et axones) ou dans l'espace extra-cellulaire. Deuxièmement, certaines caractéristiques de la matière grise du cerveau rendent l'analyse et la simulation très difficiles: \begin{enumerate} \item Les cellules sont géométriquement complexes. Les neurones ont un corps solide, mesurant 1 à 10 micromètres de diamètre auquel sont attachés de longues neurites (axones et dendrites) qui mesurent de l'ordre d'un micromètre de diamètre et de plusieurs centaines de micromètres de longueur. \item Les cellules ont une répartition très dense. Les corps neuronaux occupent 12\% du volume du cortex cérébral, les axones 34\%, les dendrites 35\%, l'espace extracellulaire 6\%, pour une largeur moyenne de 10 à 30 nanomètres. \item L'organisation cellulaire est complexe. Les cellules du cortex sont organisées en couches, avec des colonnes de cellules liant différentes couches. \item Les cellules sont perméables. En général, l'eau peut se déplacer entre les cellules et l'espace extracellulaire. \end{enumerate} La résolution d'IRMd est de l'ordre de 1 mm$^3$, ce qui signifie que chaque pixel de l'image affiche les caractéristiques de diffusion moyennées dans un volume de tissu (voxel) de 1 mm$^3$, ce qui est très grand devant les échelles spatiales cellulaires. Pour modéliser le signal de l'IMRd dans un voxel, il faut simuler l'aimantation à l'intérieur de ce voxel et calculer son intégrale au moment de l'écho. La distance de diffusion moyenne ne dépassant pas 25 micromètres, il suffit de faire le calcul dans un domaine légèrement plus grand qu'un voxel pour tenir compte de la diffusion de toutes les molécules d'eau qui auront " vu " ce voxel durant le temps de diffusion. De plus, si nous supposons que le voxel contient un environnement cellulaire qui ne varie pas beaucoup à dans le voxel, nous utilisons un domaine de calcul plus petit, celui-ci devra ne contenir qu'une " portion représentative " du tissu dans le voxel. Pour étudier le lien entre l'atténuation du signal d'IRMd et les propriétés géométriques du tissu, tels que le diamètre moyen des cellules et la fraction volumique cellulaire, nous avons généré, dans un premier temps, des domaines de calcul qui contiennent une configuration cellulaire à étudier. A terme, nous envisageons des simulations sur beaucoup de configurations pour obtenir des résultats statistiquement significatifs. Actuellement, nous construisons une seule configuration cellulaire et résolvons le problème forward et inverse associé. Le signal d'imagerie par résonance magnétique de diffusion dans le tissu biologique peut être considéré comme une sorte de " transformée de Fourier " de la fonction de densité de probabilité de déplacement de l'eau dans les milieux hétérogènes. L'aimantation des protons de l'eau en tissu biologique en présence d'impulsions du gradient de champ magnétique, peut être modélisée par une équation aux dérivées partielles (EDP), l'équation de Bloch-Torrey microscopique à compartiments multiples. Cette EDP peut être comprise comme l'attribution aux molécules d'eau en milieu hétérogène, d'une fréquence spatiale qui dépend de leurs positions. Le signal d'IRMd est l'intégrale de la solution de cette EDP au moment de l'écho. Nous avons résolu numériquement cette EDP en couplant une discrétisation spatiale cartésienne standard avec une discrétisation en temps adaptative (Runge-Kutta Chebyshev " RKC ") et nous avons étudié les caractéristiques de la diffusion d'un modèle de la matière grise du cerveau constitué de cellules cylindriques et sphériques dans l'espace extracellulaire. Puis, par homogénéisation, nous avons formulé un nouveau modèle macroscopique, sous forme d'un système d'équations aux dérivées ordinaires (EDO), pour le signal d'IRMd. Ensuite, nous avons montré par des simulations numériques que ce modèle d'EDO donne une bonne approximation du signal du modèle d'EDP complet pour des temps de diffusion relativement longs. Je mentionne aussi le travail de deux doctorants que je co-encadre actuellement. Dang Van Nguyen (soutenu par le projet SIMUDMRI, ANR COSINUS 2010-2013) a couplé une discrétisation d'éléments finis avec la méthode RKC pour obtenir une discrétisation plus précise des surfaces cellulaires. Il travaille sur l'analyse du signal de l'IRMd des neurones isolés. Huan Tuan Nguyen (soutenu par une bourse de l'École Doctorale " Sciences et Technologies de l'Information, des Télécommunications et des Systèmes " ED STITS, 2010-2013) travaille sur le problème inverse du modèle d'EDO. Enfin, j'envisage trois orientations futures de mes recherches dans l'IRMd. \begin{enumerate} \item En collaboration avec le centre Neurospin IRM, confronter les résultats numériques du modèle d'EDP avec les données expérimentales IRMd des ganglions (réseaux neuronaux) de l'Aplysie (limace de mer géante). \item Prendre en compte l'écoulement sanguin dans les micro-vaisseaux du cerveau, via un nouveau modèle d'EDP. \item Obtenir la formulation d'un nouveau modèle d'EDO valable aux temps de diffusion plus courts ou en présence des cellules plus grandes. \end{enumerate}
Books on the topic "Magnetic memory (Computers)"
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Yuan-Jen, Lee, ed. Magnetic memory: Fundamentals and technology. Cambridge University Press, 2010.
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Tang, Denny D. Magnetic memory: Fundamentals and technology. Cambridge University Press, 2010.
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Tang, Denny D. Magnetic memory: Fundamentals and technology. Cambridge University Press, 2010.
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Bolychevskiĭ, A. B. A Random interleaving of memory: Theory, simulation and a new algorithm. Institute of Automation and Electrometry, Siberian Branch USSR Ac. Sci., 1991.
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V, Drobotov I͡U. Ferritovye serdechniki zapominai͡ushchikh ustroĭstv. Ėnergoatomizdat, 1985.
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NATO Advanced Study Institute on Magnetic Storage Systems Beyond 2000 (2000 Rhodes, Greece). Magnetic storage systems beyond 2000. Kluwer Academic Publishers, 2001.
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1976-, Chen Yiran, ed. Nonvolatile memory design: Magnetic, resistive, and phase change. Taylor & Francis, 2012.
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C, Arnoldussen T., and Nunnelley L. L, eds. Noise in digital magnetic recording. World Scientific, 1992.
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W, DeHaven Patrick, ed. Magnetic and electronic films--: Microstructure, texture and application to data storage : symposia held April 1-4, 2002, San Francisco, California, U.S.A. Materials Research Society, 2002.
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1960-, Keeth Brent, ed. DRAM circuit design: Fundamental and high-speed topics. IEEE, 2007.
Find full textBook chapters on the topic "Magnetic memory (Computers)"
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Carboni, Roberto. "Characterization and Modeling of Spin-Transfer Torque (STT) Magnetic Memory for Computing Applications." In Special Topics in Information Technology. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-62476-7_5.
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AbstractWith the ubiquitous diffusion of mobile computing and Internet of Things (IoT), the amount of data exchanged and processed over the internet is increasing every day, demanding secure data communication/storage and new computing primitives. Although computing systems based on microelectronics steadily improved over the past 50 years thanks to the aggressive technological scaling, their improvement is now hindered by excessive power consumption and inherent performance limitation associated to the conventional computer architecture (von Neumann bottleneck). In this scenario, emerging memory technologies are gaining interest thanks to their non-volatility and low power/fast operation. In this chapter, experimental characterization and modeling of spin-transfer torque magnetic memory (STT-MRAM) are presented, with particular focus on cycling endurance and switching variability, which both present a challenge towards STT-based memory applications. Then, the switching variability in STT-MRAM is exploited for hardware security and computing primitives, such as true-random number generator (TRNG) and stochastic spiking neuron for neuromorphic and stochastic computing.
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Stern, Ulrich, and David L. Dill. "Using magnetic disk instead of main memory in the Mur ϕ verifier." In Computer Aided Verification. Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/bfb0028743.
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Lee, Jong-Bin, Yutaka Toi, and Minoru Taya. "Finite Element Modeling of Magneto-superelastic Behavior of Ferromagnetic Shape Memory Alloy Helical Springs." In Lecture Notes in Computer Science. Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/978-3-540-30585-9_77.
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Swade, Doron. "The computer boom." In The History of Computing: A Very Short Introduction. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/actrade/9780198831754.003.0005.
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Abstract This chapter traces the emergence of the computer from the workshop into the workplace. It describes the role of the corporate mainframe from the early 1950s to the late 1970s and IBM’s dominance. It starts with IBM’s response to the threat, to its office automation interests, posed by UNIVAC and a new generation of electronic computers. It describes the impetus given to innovation by the Cold War through the Whirlwind project and the SAGE air defence system for the US military. It describes innovative technologies including magnetic-core memory, interactive screen display, reliability protocols and techniques, double-sided printed circuit boards, real-time operating software, duplex standby, digital communication over standard telephone lines, time sharing, and software/programming disciplines. The account shows how SAGE gave IBM a head start in computing, networking, and communications, and how the migration of expertise into the private sector fuelled commercial spin-offs. It describes two sectors transformed by the new technologies: automated banking (ERMA) and the introduction of the credit card, and airline reservation (SABRE). It describes the shakeout in the computer industry in the 1960s in which IBM saw off its competitors (the ‘seven dwarves’) to secure its dominance following the radical introduction of the System/360.
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Edelman, Shimon. "Memory." In Computing the Mind. Oxford University PressNew York, NY, 2008. http://dx.doi.org/10.1093/oso/9780195320671.003.0006.
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Abstract Unlike patterns of dry ink on paper, of cuneiform indentations on a clay tablet, or of magnetic flux frozen into the surface of a computer disk, memories that reside in a living brain have a life of their own. Some will hover sombrely in the shadows, waiting to snap back at the slightest provocation; some will wander off when set free, never to be heard of again; some will come and go at your bidding; and some will lie low and ignore attempted recall, only to emerge triumphantly when least expected. Shedding light on the secret life of memories is central to the understanding of cognition because memory occupies such a prominent place in the theory of computation. As you may recall from Chapter 2, a memory “tape” is one of the two functional components of the universal abstract model of digital computation, the Turing Machine, the other one being a table that maps combinations of internal states and inputs (tape symbols) onto successor states and outputs (tape symbols). Strip a Turing Machine of its tape, and you are left with a memory-less automaton, which knows what state it is in, but not, for example, how it got there. Behaviorally, such a system is clump of hard-wired slavish reflexes, a circuit that is doomed for all eternity to retrace the same set of tracks through the space of input-state-output combinations.
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Raman Sundara Raman, Siddhartha. "A Review on Non-Volatile and Volatile Emerging Memory Technologies." In Computer Memory and Data Storage. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.110617.
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As technology scaling is approaching a stand-still with architectural advancements on modern day processors struggling to improve performance, coupled with the rise in machine learning topologies demanding better performing processors, there is a pressing need to address the reasons behind today’s performance bottleneck. These reasons include long access latency of memory technologies, scalability of memory designs, energy inefficiency incurred by increased performance, and additional area overhead. To explore these issues, a holistic understanding of existing memory technologies is essential. In this chapter, a review of different memory designs starting from volatile memory technologies such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), NAND/NOR flash to emerging non-volatile memory technologies such as Resistive Random Access Memory (RRAM), Magneto-resistive random access memory (MRAM), Ferroelectric Field effect transistor (FeFET) is presented, with specific consideration of tradeoffs involving area, performance, energy.
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Zalasiewicz, Jan. "Where on Earth?" In The Planet in a Pebble. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780199569700.003.0014.
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In some ways the pebble is like one of the newer computer chips, tightly packed with more information than one could ever surmise from gazing on its smooth surface. That stored information can relate to any episode in the history of the pebble, and could be derived from nearby—a microbial mat growing on the exact spot on the sea floor where the pebble sediment accumulated, perhaps. But it could come from afar, such as a micrometeorite landing in the ocean and drifting slowly down to land on that very same spot (there are likely a few of those in the pebble, too). Some information is as pristine as the day it was written, in its own particular code, into the pebble fabric; some, on the other hand, has been almost completely overwritten, when yet further information was imprinted at some later point in time. We might consider here some information that has most likely been all but erased by the pebble’s tumultuous subsequent history—not that that should stop us trying to recover what we can of it. Nevertheless, when it was written into the fabric of the pebble, it provided a clear signal that travelled easily through some 4000 miles of solid rock, straight from the centre of the Earth. This signal gently nudged and guided certain of the flakes of sediment falling on to that sea floor. It made them line up, with almost military precision, to point polewards. They form a memory of latitude. The Earth’s magnetic field is a mysterious thing. What is magnetism? As a child, I used to push together the north poles of two toy magnets, and remember even now how frustratingly difficult it was to make them touch—or how tricky it was to prevent the north and south poles from locking together when I tried to keep them just a tiny bit apart. A few years later, I looked on, impressed but with incomprehension, as a physics teacher sprinkled iron filings around a magnet, to show how they lined up along the invisible lines of force.
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Copeland, Jack, and Jason Long. "Computer music." In The Turing Guide. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198747826.003.0032.
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One of Turing’s contributions to the digital age that has largely been overlooked is his groundbreaking work on transforming the computer into a musical instrument. It is an urban myth of the music world that the first computer-generated musical notes were heard in 1957, at the Bell Laboratories in the United States. In fact, computer-generated notes were heard in Turing’s Computing Machine Laboratory at Manchester University about nine years previously. This chapter establishes Turing’s pioneering role in the history of computer music. We also describe how Christopher Strachey, later Oxford University’s first professor of computing, used and extended Turing’s note-playing subroutines so as to create some of the earliest computer-generated melodies. A few weeks after Baby ran its first program (see Chapter 20) Turing accepted a job at Manchester University. He improved on Baby’s bare-bones facilities, designing an input–output system based on wartime cryptographic equipment (see Chapter 6). His tape reader, which used the same teleprinter tape that ran through Colossus, converted the patterns of holes punched across the tape into electrical pulses and fed these to the computer. The reader incorporated a row of light-sensitive cells that read the holes in the moving tape—the same technology that Colossus had used. As the months passed, a large-scale computer took shape in the Manchester Computing Machine Laboratory. Turing called it the ‘Manchester Electronic Computer Mark I’ (Fig. 23.1). A broad division of labour developed that saw Kilburn and Williams working on the hardware and Turing on the software. Williams concentrated his efforts on developing a new form of supplementary memory, a rotating magnetic drum, while Kilburn took the leading role in developing the other hardware. Turing designed the Mark I’s programming system, and went on to write the world’s first programming manual. The Mark I was operational in April 1949, although additional development continued as the year progressed. Ferranti, a Manchester engineering firm, contracted to build a marketable version of the computer, and the basic designs for the new machine were handed over to Ferranti in July 1949. The very first Ferranti computer was installed in Turing’s Computing Machine Laboratory in February 1951 (Fig. 23.2), a few weeks before the earliest American-built marketable computer, the UNIVAC I, became available.
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Nahin, Paul J. "Turing Machines." In The Logician and the Engineer. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691176000.003.0009.
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This chapter discusses Turing machines. A Turing machine is the combination of a sequential, finite-state machine plus an external read/write memory storage medium called the tape (think of a ribbon of magnetic tape). The tape is a linear sequence of squares, with each square holding one of several possible symbols. The Turing machine's power to compute comes from its tape, for two reasons. First, Turing was the first to conceive of the idea of a stored program that could be changed by the operation of the machine itself. The program, and its input data, exist together on the tape as sequences of symbols. Second, because of the arbitrarily long length of the tape, a Turing machine has the ability to “remember” what has happened in the arbitrarily distant past.
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Zee, Chi-Shing, John L. Go, Paul E. Kim,, and Daoying Geng. "Computed Tomography and Magnetic Resonance Imaging in Traumatic Brain Injury." In Neurology And Trauma. Oxford University PressNew York, NY, 2006. http://dx.doi.org/10.1093/oso/9780195170320.003.0003.
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Abstract Head trauma is the major cause of accidental death in the United States, particularly in the juvenile and young adult groups.11,17,18,32 Severe traumatic brain injury (TBI) accounts for a death rate of 16.9 per 100,000 population per year.44 Motor vehicle accidents (57%), firearms injuries (14%), and traumatic falls (12%) are the most frequent causes. Males are three times more likely to die from brain injury–associated death than females. Head injuries are responsible for 200 to 300 hospital admissions per 100,000 population per year in the United States.6 Most of the admissions last only a few days, and the patients are admitted for clinical observation. Head injury is not only a cause of death but also a cause of serious financial burden to the society providing treatment and care to these patients. Lost labor and reduced productivity to the society further add to the negative impact. The cost of head trauma to the society is estimated to be billions of dollars annually. The majority of the patients suffering head injuries are considered to have mild head injury. Most patients recover fully from mild TBI, but 15% to 29% of patients with mild TBI may have significant neurocognitive problems.27 Common symptoms include attention deficit, deficit in working memory and speed of information processing; headaches, dizziness, and irritability.
Conference papers on the topic "Magnetic memory (Computers)"
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"An application of magnetic bubbles to a spaceborne mass memory system." In 5th Computers in Aerospace Conference. American Institute of Aeronautics and Astronautics, 1985. http://dx.doi.org/10.2514/6.1985-5078.
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Ryoo, Young-Jae, Young-Hak Chang, Dae-Yeong Lim, and Yong-Jun Lee. "Autonomous Robotic Vehicle (Robicle) With Ambient Intelligence." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86986.
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Magnetic sensing is a reliable technology that has been developed for the purposed of position measurement and guidance, especially for applications in autonomous robotic vehicles. To calculate a position of a magnetic guidance road, it should be estimated in real-time. While the capability of a microprocessor and memory spaces have the limitation in implementation. To solve the above problems, this paper proposes a new structure of the magnetic sensors included a vertical magnetic field. The proposed method uses the linear region of the sensor output, and position determination using a simple equation with a microcontroller. The position sensing technique was implemented in the guidance of autonomous vehicle. The test results show that position sensing can be useful for an autonomous robotic vehicle.
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Lan, Chao-Chieh, and You-Nien Yang. "An Analytical Design Method for a Shape Memory Alloy Wire Actuated Compliant Finger." In ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49045.
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This paper presents an analytical method to design a mechanical finger for robotic manipulations. As traditional mechanical fingers require bulky electro-magnetic motors and numerous relative-moving parts to achieve dexterous motion, we propose a class of fingers the manipulation of which relies on finger deflections. These compliant fingers are actuated by shape memory alloy (SMA) wires that exhibit high work-density, frictionless, and quite operations. The combination of compliant members with embedded SMA wires makes the finger more compact and lightweight. Various SMA wire layouts are investigated to improve their response time while maintaining sufficient output force. The mathematical models of finger deflection caused by SMA contraction are then derived along with experimental validations. As finger shapes are essential to the range of deflected motion and output force, we find its optimal initial shapes through the use of a shape parameterization technique. We further illustrate our method by designing a humanoid finger that is capable of three-dimensional manipulation. As compliant fingers can be fabricated monolithically, we expect the proposed method to be utilized for applications of various scales.
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Tyagi, Pawan, and Christopher D’Angelo. "A Monte Carlo Study of Molecular Spintronics Devices." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62413.
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Molecular spintronics devices (MSDs) are capable of harnessing the controllable transport and magnetic properties of molecular device elements and are highly promising candidates for revolutionizing computer logic and memory. These advanced MSD can enable the next generation of instrumentation and control devices for the wide range of mechanical engineering systems. A MSD is typically produced by placing magnetic molecule(s) between the two ferromagnetic electrodes. Recent experimental studies show that some magnetic molecules produced unprecedented strong exchange couplings between the two ferromagnetic electrodes, leading to intriguing magnetic and transport properties in a MSD. Future development of MSDs will critically depend on obtaining an in-depth understanding of the molecule induced exchange coupling, and its impact on MSD’s switchability, functional temperature range, stability etc. However, the large size of MSD systems and unsuitable device designs are the two biggest hurdles in theoretical and experimental studies of magnetic attributes produced by molecules in a MSD. This research theoretically studies the MSD by performing Monte Carlo simulations (MCS). The effect of magnetic molecule induced exchange coupling was studied at different temperature and for different device sizes — represented by a 2D Ising model. Our MCS shows that thermal energy of the MSD strongly influenced the molecular coupling effect. We studied the effect of a wide range of molecule-metal electrode couplings on the fundamental properties of MSDs. If molecules induced exchange coupling increased beyond a threshold limit a MSD acquired dramatically new attributes. Our MCS exhibited that the transition points in MSD’s magnetic properties was the interplay of temperature and molecular coupling strength. These simulations will allow the understanding of fundamental device mechanisms behind the functioning of novel MSDs. Our MSD model represents a myriad of magnetic molecules and ferromagnets combinations promising for realizing experimental MSDs. These MCS will also assist in designing new class of MSDs with desired attributes for advanced computers and control systems.
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Pappafotis, Nicholas, Wojciech Bejgerowski, Rao Gullapalli, J. Marc Simard, Satyandra K. Gupta, and Jaydev P. Desai. "Towards Design and Fabrication of a Miniature MRI-Compatible Robot for Applications in Neurosurgery." In ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49587.
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Brain tumors are among the most feared complications of cancer and they occur in 20–40% of adult cancer patients. Despite numerous advances in treatment, the prognosis for these patients is poor, with a median survival of 4–8 months. The primary reasons for poor survival rate are the lack of good continuous imaging modality for intraoperative intracranial procedures and the inability to remove the complete tumor tissue due to its placement in the brain and the corresponding space constraints to reach it. Intraoperative magnetic resonance imaging (MRI) supplements the surgeon’s visual and tactile senses in a way that no other imaging device can achieve resulting in less trauma to surrounding healthy brain tissue during surgery. To minimize the trauma to surrounding healthy brain tissue, it would be beneficial to operate through a narrow surgical corridor dissected by the neurosurgeon. Facilitating tumor removal by accessing regions outside the direct “line-of-sight” of the neurosurgical corridor will require a highly dexterous, small cross section, and MRI-compatible robot. Developing such a robot is extremely challenging task. In this paper we report a preliminary design of 6-DOF robot for possible application in neurosurgery. The robot actuators and body parts are constructed from MRI compatible materials. The current prototype is 0.36” in diameter and weighs only 0.0289 N (2.95 grams). The device was actuated using Flexinol® which is a shape memory alloy manufactured by Dynalloy, Inc. The end-effector forces ranged from 12 mN to 50 mN depending on the robot configuration. The end-effector force to robot weight ratio varied from 0.41 to 1.73. During trials the robot motion was repeatable and the range of motion of the robot was about 90 degrees for the end-effector when one side shape memory alloy (SMA) channel was actuated. The actuation time from the start to finish was about 2.5 s.
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Wang, Lei, Chengying Xu, Zelin Zhang, and Xuhui Xia. "Decision Fusion Method for the Failure Form of Retired Parts Based on Cloud Model Optimization D-S Evidence Theory." In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-89657.
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Abstract The decision-making fusion of multi-source failure information for retired parts is vital to classify the failure forms of retired parts. There are various failure information detection methods for retired parts, however the results obtained by different detection methods are biased, one-sided, and uncertain, resulting in difficulty in decision making. Aiming at improving the classification accuracy and reliability of the failure forms for retired parts, we propose a fusion method for retired parts failure form decision-making based on the cloud-model optimization D-S evidence theory (CM-D-S). The cloud model solves the problem of strong subjectivity in the traditional D-S evidence theory and overcomes the negative effects caused by random factors. Through image processing, magnetic memory, and ultrasonic testing, the multi-source failure information of retired parts can be obtained, and the failure forms of retired parts are divided into fracture, corrosion, wear and deformation. The cloud model parameters are used to characterize different failure feature quantities sequentially, obtain the basic probability assignment matrix in the D-S evidence theory, and substituted into the D-S evidence theory model to combine and optimize multi-source failure information, and output the result of decision fusion, which is the multi-source failure form of the retired parts. The case shows that the CM-D-S decision-making method has high accuracy for failure form recognition, which proves the applicability and feasibility of the method.
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Makowski, M., J. Bomba, M. Sypek, T. Shimobaba, T. Ito, and A. Stupakiewicz. "Ultrafast, Memory-Less Computation and Rewriting of Complex Holograms in the Opto-Magnetic Medium." In Digital Holography and Three-Dimensional Imaging. Optica Publishing Group, 2022. http://dx.doi.org/10.1364/dh.2022.th1a.5.
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The novel scheme of serial, memory-less computation, storing and refreshing of complex computer-generated holograms is demonstrated in transparent ultra-fast opto-magnetic medium exhibiting threshold effect, allowing sub-diffraction limited, point-by-point recording of diffractive fringes with picosecond response.
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Abiko, T., A. Konishi, M. Kagawa, and S. Igarashi. "A New Thermal Response Design for High Recording Density Magneto-Optical Media." In Symposium on Optical Memory. Optica Publishing Group, 1996. http://dx.doi.org/10.1364/isom.1996.owd.6.
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Recent magneto-optical ( MO ) disk systems adopt mark length modulation technique in order to improve linear recording density, in which the mark edges have to be recorded more precisely. In light intensity modulation recording MO system such as ISO standardized format, however, recorded marks are deformed because of thermal interference in write process. One of the most effective method to prevent the thermal interference is to use write compensation technique with elaborated write pulse patterns.[1] From this point of view, the thermal response design of recording layer structure must be serious subject in next generation MO disk media. We have investigated new layer structure suitable for higher density format. By means of a computer simulation, it is shown that the thermal response is improved by using a 6 recording layer structure, which has an extra thermal flow control layer. The improvement of recording characteristics is also confirmed experimentally.
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Ohsawa, S., M. Tusge, A. Takatsu, T. Okunishi, J. Tanaka, and S. Mikami. "A Thermosetting Resin Substrate for Computer-Use Optical Memory Disks." In Optical Data Storage. Optica Publishing Group, 1985. http://dx.doi.org/10.1364/ods.1985.thcc4.
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A thermosetting resin (epoxy resin) substrate for computer-use write-once, phase-change and magneto-optical memory disks has been developed and its optical, physical, thermal and mechanical properties are described in comparison with other plastic substrates.
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Bakhtiyarov, Sayavur I., Geilani M. Panahov, Eldar M. Abbasov, and Chingiz Y. Heydarov. "Rheological Measurements on Viscoelastic Self-Healing Composites Used in Oil Industry." In ASME 2005 Fluids Engineering Division Summer Meeting. ASMEDC, 2005. http://dx.doi.org/10.1115/fedsm2005-77309.
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In this paper we present the results of the rheological property measurements on viscoelastic composite materials used in oil industry. Laboratory experiments were carried out to determine important thermophysical, rheological and mechanical properties of the test materials using both the standard commercial and in-house made equipment. The composites with the paramagnetic particles (γ-iron oxide) are exhibited a significant magnetic memory after magnetic treatment. The measured value of the yield stress after the magnetic treatment increased almost twice in comparison with the yield stress value of the magnetically untreated composite. The yield stress of the composite material exponentially decreases with time and reaches its magnetically untreated value after 15 hours. The yield stress also increases with the amount of the paramagnetic powder additive, and it reaches a maximum value at 8 wt% of this additive. The obtained results provide a valuable information for computer modeling of the viscoelastic fluid flow in pipes of complex geometry.