15 research outputs found
Quantum-dot Cellular Automata: Review Paper
Quantum-dot Cellular Automata (QCA) is one of the most important discoveries that will be the successful alternative for CMOS technology in the near future. An important feature of this technique, which has attracted the attention of many researchers, is that it is characterized by its low energy consumption, high speed and small size compared with CMOS. Inverter and majority gate are the basic building blocks for QCA circuits where it can design the most logical circuit using these gates with help of QCA wire. Due to the lack of availability of review papers, this paper will be a destination for many people who are interested in the QCA field and to know how it works and why it had taken lots of attention recentl
Fault and Defect Tolerant Computer Architectures: Reliable Computing With Unreliable Devices
This research addresses design of a reliable computer from unreliable device technologies. A system architecture is developed for a fault and defect tolerant (FDT) computer. Trade-offs between different techniques are studied and yield and hardware cost models are developed. Fault and defect tolerant designs are created for the processor and the cache memory. Simulation results for the content-addressable memory (CAM)-based cache show 90% yield with device failure probabilities of 3 x 10(-6), three orders of magnitude better than non fault tolerant caches of the same size. The entire processor achieves 70% yield with device failure probabilities exceeding 10(-6). The required hardware redundancy is approximately 15 times that of a non-fault tolerant design. While larger than current FT designs, this architecture allows the use of devices much more likely to fail than silicon CMOS. As part of model development, an improved model is derived for NAND Multiplexing. The model is the first accurate model for small and medium amounts of redundancy. Previous models are extended to account for dependence between the inputs and produce more accurate results
Multiple bit error correcting architectures over finite fields
This thesis proposes techniques to mitigate multiple bit errors in GF arithmetic circuits. As GF arithmetic circuits such as multipliers constitute the complex and important functional unit of a crypto-processor, making them fault tolerant will improve the reliability of circuits that are employed in safety applications and the errors may cause catastrophe if not mitigated.
Firstly, a thorough literature review has been carried out. The merits of efficient schemes are carefully analyzed to study the space for improvement in error correction, area and power consumption.
Proposed error correction schemes include bit parallel ones using optimized BCH codes that are useful in applications where power and area are not prime concerns. The scheme is also extended to dynamically correcting scheme to reduce decoder delay. Other method that suits low power and area applications such as RFIDs and smart cards using cross parity codes is also proposed. The experimental evaluation shows that the proposed techniques can mitigate single and multiple bit errors with wider
error coverage compared to existing methods with lesser area and power consumption. The proposed scheme is used to mask the errors appearing at the output of the circuit irrespective of their cause.
This thesis also investigates the error mitigation schemes in emerging technologies (QCA, CNTFET) to compare area, power and delay with existing CMOS equivalent. Though the proposed novel multiple error correcting techniques can not ensure 100% error mitigation, inclusion of these techniques
to actual design can improve the reliability of the circuits or increase the difficulty in hacking crypto-devices. Proposed schemes can also be extended to non GF digital circuits
Light in correlated disordered media
The optics of correlated disordered media is a fascinating research topic
emerging at the interface between the physics of waves in complex media and
nanophotonics. Inspired by photonic structures in nature and enabled by
advances in nanofabrication processes, recent investigations have unveiled how
the design of structural correlations down to the subwavelength scale could be
exploited to control the scattering, transport and localization of light in
matter. From optical transparency to superdiffusive light transport to photonic
gaps, the optics of correlated disordered media challenges our physical
intuition and offers new perspectives for applications. This article reviews
the theoretical foundations, state-of-the-art experimental techniques and major
achievements in the study of light interaction with correlated disorder,
covering a wide range of systems -- from short-range correlated photonic
liquids, to L\'evy glasses containing fractal heterogeneities, to hyperuniform
disordered photonic materials. The mechanisms underlying light scattering and
transport phenomena are elucidated on the basis of rigorous theoretical
arguments. We overview the exciting ongoing research on mesoscopic phenomena,
such as transport phase transitions and speckle statistics, and the current
development of disorder engineering for applications such as light-energy
management and visual appearance design. Special efforts are finally made to
identify the main theoretical and experimental challenges to address in the
near future.Comment: Submitted to Reviews of Modern Physics. Feedbacks are welcom
Analysis of field usage failure rate data for plastic encapsulated solid state devices
Survey and questionnaire techniques were used to gather data from users and manufacturers on the failure rates in the field of plastic encapsulated semiconductors. It was found that such solid state devices are being successfully used by commercial companies which impose certain screening and qualification procedures. The reliability of these semiconductors is now adequate to support their consideration in NASA systems, particularly in low cost systems. The cost of performing necessary screening for NASA applications was assessed
Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields
Innovations in Road, Railway and Airfield Bearing Capacity – Volume 1 comprises the first part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field
The status and use of computer network attacks in international humanitarian law.
The information revolution has transformed both modern societies and the way in which they conduct warfare. This thesis analyses the status of computer network attacks in international law and examines their treatment under the laws of armed conflict. A computer network attack is any operation designed to disrupt, deny, degrade or destroy information resident in computers and computer networks, or the computers and networks themselves. The first part of the thesis deals with a States right to resort to force and uses the U.N. Charter system to analyse whether and at what point a computer network attack will amount to a use of force or an armed attack, and examines the permitted responses against such an attack. The second part of the thesis addresses the applicability of international humanitarian law to computer network attacks by determining under what circumstances these attacks will constitute an armed conflict. It concludes that the jus in bello will apply where the perceived intention of the attacking party is to cause deliberate harm and the foreseeable consequence of the acts includes injury, death damage or destruction. In examining the regulation of these attacks under the Jus in bello the author addresses the legal issues associated with this method of attack in terms of the current law and examines the underlying debates which are shaping the modern laws applicable in armed conflict. Participants in conflicts are examined as increased civilianisation of the armed forces is moving in lock-step with advances in technology. Computer network attacks also present new issues for the law relating to targeting and precautions in attack which are addressed; objects subject to special protections, and their digital counterparts are also examined. Finally the thesis addresses computer network attacks against the laws relating to means and methods of warfare, including the law of weaponry, perfidy and the particular issues relating to digital property