Quantum-dot cellular automata (QCA) is a new and promising computation paradigm, which can be a viable replacement for the complementary metal–oxide–semiconductor technology at nano-scale level. This technology provides a possible solution for improving the computation in various computational applications. Two QCA full adder architectures are presented and evaluated: a new and efficient 1-bit QCA full adder architecture and a 4-bit QCA ripple carry adder (RCA) architecture. The proposed architectures are simulated using QCADesigner tool version 2.0.1. These architectures are implemented with the coplanar crossover approach. The simulation results show that the proposed 1-bit QCA full adder and 4-bit QCA RCA architectures utilise 33 and 175 QCA cells, respectively. Our simulation results show that the proposed architectures outperform most results so far in the literature.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/joe.2017.0223

High-performance full adder architecture in quantum-dot cellular automata

This paper outlines low power nano-scale circuit design for even parity generator, as well as, even parity checker circuit using quantum-dot cellular automata (QCA). The proposed even parity generator and even parity checker are achieved by using a new layout of XOR gate. This new XOR gate as a state-of-the-art is much denser and faster than the existing ones. The proposed parity generator has outshined the existing design by reducing the cell count as 10%, area as 5.66%, and latency by 12.5%. The proposed parity checker has also outshined the existing design with an improvement in cell count as 17.94% and in the area as 38.46% having a reduction in latency of 22.22%. The comparison proves that the circuits are denser and faster than the existing one. Nano communication architecture with the proposed circuits also demonstrates the efficiency of this design. Furthermore, the bit-error coverage by the proposed method is described. Besides, the defects in the circuits are explored to facilitate guide to proper implementation. The tests vectors are proposed to identify the defects in the designs and the defect coverage by those test vectors. The estimation of dissipated energy by the layouts establishes a very low energy dissipation nature of the designs. Different parameters like a logic gate, density, and latency are utilized to evaluate the proposed designs that confirm the faster processing speed at nano-scale.

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QCA Based Error Detection Circuit for Nano Communication Network

Despite its important existing challenges, quantum-dot cellular automata (QCA) is one of the promising replacement candidates of the traditional VLSI technology. Practical implementation issues such as fault tolerance and lack of customized CAD tools and algorithms for automatic synthesis of large complex systems are some important instances of QCA circuit design challenges. Currently, most of the research papers focus only on development of individually efficient QCA gates and circuits in terms of only their physical properties such as area and delay. However, throughout this paper, it is demonstrated that these compressed and fast individual QCA gates and circuits cause serious concerns when they are exploited as building blocks in modular design of higher level complex circuits. Some simple but effective design rules are then emphasized to solve this problem by preserving the “modular design efficiency” of the developed underlying QCA gates and circuits. As a case study, two new instances of fault-tole...

A Fault-Tolerant and Efficient XOR Structure for Modular Design of Complex QCA Circuits

Implementation of basic ternary logic gates is more complex than binary gates in quantum-dot cellular automata (QCA) technology. Several models have been presented for designing ternary logic gates. Most of these models are different solutions and are based on manual calculations. It seems that no simulation tool for designing ternary QCA (tQCA) logic gates has been presented. Unlike previous works, this study is an attempt to introduce an alternative model and the related software for tQCA logic gates. Prominent basic ternary logic gates - such as Min gate, Max gate and inverter - are proposed and simulated in the newly designed TQCAsim software which is an accurate simulation and design tool and is based on the algorithm proposed in this study. Unlike QCA designer software, which has been designed for binary QCA, TQCAsim is designed exclusively for tQCA. Thus, this software can be used to verify and implement the proposed tQCA gates and even earlier designs.

Innovative model for ternary QCA gates

Quantum-dot cellular automata (QCA), one of the alternative CMOS technologies at a nano scale, promises to design digital circuits with extra low-power, extremely dense and high speed structures. In this paper, a new QCA gate with three inputs and two outputs is first introduced; this operates on the basis of cell interactions. Then, low complexity and high-speed QCA full-adder and full-subtractor structures are proposed by applying different formulations, which are based on the introduced gate. Finally, a novel QCA full adder/subtractor is presented with the synergy of the proposed QCA full-adder and full-subtractor structures as well as a proposed optimal single layer 2:1 QCA multiplexer. The proposed designs are simulated using the QCA Designer 2.0.3. The simulation results confirm that the proposed circuits work well. A comparative analysis indicates the superiority of the proposed designs compared to the other related designs. Moreover, the QCAPro power estimator tool is utilized to evaluate the power dissipation of the proposed designs.

A Novel Full Adder/Subtractor in Quantum-Dot Cellular Automata

Among all basic arithmetic operations, the division is the most complex one. On the other hand, working on post-complementary metal–oxide–semiconductor (CMOS) technology attracts attention of many researchers, while the progress of miniaturisation in CMOS technology faced physical limits. Therefore, in this study, the authors propose a non-restoring divider in quantum-dot cellular automata (QCA), as one of the most promising technology. To achieve an efficient divider, they propose a novel 1 bit full-adder and take advantage of improved design of XOR gate. This design has considerable improvements in terms of cell numbers, delay and area, compared with other dividers. The suggested design is simulated in QCADesigner software and acceptable results are achieved.

Design of non-restoring divider in quantum-dot cellular automata technology

This experimental study aims to investigate the ability of the ultrasonic method (UM) by using critically refracted longitudinal (LCR) wave for measuring stress in both elastic and plastic limits. In so doing, nine tensile test specimens are used. In order to send and receive the LCR wave into the specimens, the investigation led to design two different types of ultrasonic fixtures (constant fixture and variable fixture). The constant fixture, used to evaluate and compare the results of variable fixture. Three initial distances (0, 30, 50 mm) employed for variable fixture to detect the accurate results and compare with the constant fixture. To determine acoustoelastic and acoustoplastic constants different amounts of stress are applied to the specimens using uniaxial tensile testing machine. Measurement of longitudinal applied stress by UM is done by using 2 MHz probes based on Acoustoelasticity. The results of the study indicated that there is a significant relation between stress and time of flight wave in both elastic and plastic limits. For the first time, this study shows that entering the plastic limit takes tremendous sensitivity. By using variable fixture (without initial distance) enable the process to evaluate stress in the plastic limit accurately. The outcome of the study provides three acoustoplastic and three acoustoelastic constants. All of these constants, by increasing the initial distance between two parts of the variable fixture will reduce. In other words, the comparison between different initial distance tests indicates that increasing initial distance caused to less accuracy of measuring stress.

Determination of acoustoelastic/acoustoplastic constants to measure stress in elastic/plastic limits by using LCR wave

Determination of an optimal location for plant installation over water transmission lines leads not only to reduction in the cost of construction and energy transmission, but also to enhancement of...

Optimal location for installing small hydropower plant on water supply pipelines

In recent years, the limitations of the physical dimensions and high consumption of energy in electronic systems have been a major challenge. In order to decrease the physical size and energy consumption, various technologies have been investigated at the nano-scale. One of which is quantum cellular automata (QCA). This paper elaborates on the advantages of molecular QCA (MQCA) and proposes a new idea based on particle wave duality of free electron in QCA for energy dissipation analysis. The first stage is to calculate the dissipation of the internal dynamical and statically power of the cells considering the inner interaction of molecules. In return, by elaborating the inner calculation and consideration the distances and real size of the cells, energy dissipation values of MQCAs is calculated. Then, energy dissipation values for MQCA circuits consisting of binary wire and a majority gate are calculated. The achieved results show that in MQCA circuits, energy dissipation is very low. In addition, most of the energy dissipation in such circuits is related to the dynamical dissipation of the system. Our new concept proposes the separate use of classical physics and quantum mechanics properties in the calculation. Cell polarization changes simulated stage by stage based on current situation of electron and in each stage, the best conditions for calculations considered. The main innovation of this work is to introduce a new model based on particle wave duality for free electrons in MQCAs. In addition we presented equations to calculate total dissipation consisting dynamical and statically dissipation of MQCA circuits.

Introducing a novel model based on particle wave duality for energy dissipation analysis in MQCA circuits

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/pdf/study-of-labyrinth-spillways-with-curved-planform-5chbgyz1r6.pdf

Mohammad Mohammadi

Papers

Design of non-restoring divider in quantum-dot cellular automata technology

Determination of acoustoelastic/acoustoplastic constants to measure stress in elastic/plastic limits by using LCR wave

Optimal location for installing small hydropower plant on water supply pipelines

Introducing a novel model based on particle wave duality for energy dissipation analysis in MQCA circuits

Study of Labyrinth Spillways with Curved Planform