Presentation of a fault tolerance algorithm for design of quantum-dot cellular automata circuits

A novel algorithm for working out the Kink energy of quantum-dot cellular automata (QCA) circuits and their fault tolerability is introduced. In this algorithm at first with determining the input values on a specified design, the calculation between cells makes use of Kink physical relations will be managed. Therefore, the polarization of any cell and consequently output cell will be set. Then by determining missed cell(s) on the discussed circuit, the polarization of output cell will be obtained and by comparing it with safe state or software simulation, its fault tolerability will be proved. The proposed algorithm was implemented on a novel and advance fault tolerance full adder whose performance has been demonstrated. This algorithm could be implemented on any QCA circuit. Noticeably higher speed of the algorithm than simulation and traditional manual methods, expandability of this algorithm for variable circuits, beyond of four-dot square of QCA circuits, and the investigation of several damaged cells instead just one and special cell are the advantages of algorithmic action

Improving the reliability in bio-nanosensor modules using hardware redundancy techniques

A nano-robot is a controlled robotic system at the nanoscale. Nowadays, nanorobotics has become of particular interest in medicine and pharmacy. The accurate diagnosis of the diseases as well as their rapid treatment will make everyone surprised and will significantly reduce the associated risks. The modeling of reliability in biosensors is studied for the first time in this paper. The use of practical hardware redundancy has turned into the most cost-effective to improve the reliability of a system. Additionally, the Markov model is used to design fault-tolerant systems in nanotechnology. The proposed method is compared with some existing methods, such as triple modular redundancy and non-fault-tolerant systems; it is shown that using this method, a larger number of faults between 3-5 can be tolerated. Using the proposed method, the number of modules can be increased to nine. However, a larger number than 9 MR is not recommended because of an increased delay and requiring more hardware. As the scale of components used in digital systems has gotten smaller, the use of hardware redundancy has become cost-effective. But there is a trade-off between the amount of used hardware and fault tolerance, which can also be investigated

Novel Design for Quantum Dots Cellular Automata to Obtain Fault-Tolerant Majority Gate

Quantum-dot Cellular Automata (QCA) is one of the most attractive technologies for computing at nanoscale. The principle element in QCA is majority gate. In this paper, fault-tolerance properties of the majority gate is analyzed. This component is suitable for designing fault-tolerant QCA circuits. We analyze fault-tolerance properties of three-input majority gate in terms of misalignment, missing, and dislocation cells. In order to verify the functionality of the proposed component some physical proofs using kink energy (the difference in electrostatic energy between the two polarization states) and computer simulations using QCA Designer tool are provided. Our results clearly demonstrate that the redundant version of the majority gate is more robust than the standard style for this gate

New method for decreasing the number of quantum dot cells in QCA circuits

A method for decreasing the number of Quantum Dot Cells in Quantum Dot Cellular Automata (QCA) circuits is presented. The proposed method is based on physical relation and computing physical forces between electrons. Correctness of our method is proved using some simple physical proofs. Our method is useful when the QCA circuit has many inverter gates. It should be noted that in order to achieve more stability, electrons of QCA arrange in such a manner that their potential energy reaches the minimum level. From physical terms it could be simply proven that calculation of resultant of forces and moment of forces and also calculation of potential energy will have equal result. Therefore one can claim that the final inverter has the minimum potential energy and therefore is in its most stable state

Five-input majority gate, a new device for quantum-dot cellular automata

Quantum-dot Cellular Automata (QCA) is one of the most attractive technologies for computing at nano-scale. The principle logic element in QCA is majority gate. In this paper, a novel design for 5-input majority gate is presented. A 5-input majority gate study has been proposed; however this study has changed the scheme of basic QCA cells. The new proposed device reduces cell counts and area and uses conventional form of QCA cells. Accuracy of this design is proven by applying some simple physical substantiation and QCADesigner tool is used for verifying majority circuit layout and functionality. Furthermore, a QCA Full-Adder is constructed using the new proposed design. Simulation results demonstrate that the proposed design of majority gates and Full-Adder resulted in significant improvements in designing logical circuits