Novel low power reversible binary incrementer design using quantum-dot cellular automata

This paper demonstrates the design of n-bit novel low power reversible binary incrementer in Quantum-Dot Cellular Automata (QCA). The comparison of quantum cost in quantum gate based approach and in QCA based design agreed the cost efficient implementation in QCA. The power dissipation by proposed circuit is estimated, which shows that the circuit dissipates very low heat energy suitable for reversible computing. All the circuits are evaluated in terms of logic gates, circuit density and latency that confirm the faster operating speed at nano scale. The reliability of the circuit under thermal randomness is explored which describes the efficiency of the circuit.     

Towards modular binary to gray converter design using LTEx module of quantum-dot cellular automata

A modular approach to realize the ultra-fast quantum-dot cellular automata (QCA) generic binary to gray converter is presented in this paper. The novel designs here validated fully exploit the intrinsic repetitive capabilities of the Layered T Exclusive OR (LTEx) module in the QCA domain. An efficient logic formulation of QCA design metrics like O-Cost and delay is proposed for the n-bit QCA binary to gray converter designs. The QCA implementation of n-bit LTEx binary to gray converter is compared with the conventional converters. An attempt has been made to enhance the speed of modular binary to gray converter designs. The proposed 4, 8, 16, 32, 64-bit binary to gray converters need 4.35, 15.88, 15.96, 15.7, 16.68% less O-cost and 11.57, 2.61, 9.32, 12.64, 29.25% less effective area, respectively. Thus the proposed layouts offer the smaller feature size, reduced circuit complexity exploiting the modular based design approach. The simulation results have been carried out in the renowned computer aided design tool, namely QCADesigner 2.0.3 with gallium arsenide heterostructure based parameter environment.

     

A novel design of 8-bit adder/subtractor by quantum-dot cellular automata

Application of quantum-dot is a promising technology for implementing digital systems at nano-scale. QCA supports the new devices with nanotechnology architecture. This technique works based on electron interactions inside quantum-dots leading to emergence of quantum features and decreasing the problem of future integrated circuits in terms of size. In this paper, we will successfully design, implement and simulate a new full adder based on QCA with the minimum delay, area and complexities. Also, new XOR gates will be presented which are used in 8-bit controllable inverter in QCA. Furthermore, a new 8-bit full adder is designed based on the majority gate in the QCA, with the minimum number of cells and area which combines both designs to implement an 8-bit adder/subtractor in the QCA. This 8-bit adder/subtractor circuit has the minimum delay and complexity. Being potentially pipeline, the QCA technology calculates the maximum operating speed.     

Design and simulation of nano-arbiters using quantum-dot cellular automata

Arbiters are the essential components of the Network-On-Chip (NOC) systems and are used to resolve the contention problem where multiple requests must be handled for shared resources. On the other hand, with the ever-increasing downsizing trend in the fabrication technology, Quantum-dot Cellular Automata (QCA) with its nano scales and very low power consumption is a promising candidate for implementing future NOCs. In the current work, we design and simulate nano-arbiters using QCA with the following contributions: i) The 2-bit Basic Round Robin Arbiter (RRA) and the 2-bit Ping Pong Arbiter (PPA) are designed and simulated; ii) A solution for an erroneous condition found in the original circuit of RRA is reported and fixed; iii) We use Cartesian Genetic Programming (CGP) approach to simplify the RRA and PPA designs; iv) In order to leverage our QCA designs, we apply a more realistic clock distribution (2-DW clocking) and report the results. At the end, a one-to-one comparison of the two arbiters designed with QCA will be presented using such benchmarks as area, latency, etc. Our results show that in the 2-bit input mode, the PPA arbiter has the best overall performance.     

Operational efficiency of novel SISO shift register under thermal randomness in quantum-dot cellular automata design

Microsystem Technologies - For nano scale logic circuit, device area and power consumption are the major concerns. In this paper, the design of an optimized SISO shift register is explored based on...     

Design of dual-edge triggered flip-flops based on quantum-dot cellular automata

Quantum-dot cellular automata (QCA) technology has been widely considered as an alternative to complementary metal-oxide-semiconductor (CMOS) due to QCA’s inherent merits.Many interesting QCA-based logic circuits with smaller feature size,higher operating frequency,and lower power consumption than CMOS have been presented.However,QCA is limited in its sequential circuit design with high performance flip-flops.Based on a brief introduction of QCA and dual-edge triggered (DET) flip-flop,we propose two original QCA-based D and JK DET flip-flops,offering the same data throughput of corresponding single-edge triggered (SET) flip-flops at half the clock pulse frequency.The logic functionality of the two proposed flip-flops is verified with the QCADesigner tool.All the proposed QCA-based DET flip-flops show higher performance than their SET counterparts in terms of data throughput.Furthermore,compared with a previous DET D flip-flop,the number of cells,covered area,and time delay of the proposed DET D flip-flop are reduced by 20.5%,23.5%,and 25%,respectively.By using a lower clock pulse frequency,the proposed DET flip-flops are promising for constructing QCA sequential circuits and systems with high performance.     

On the impact of the synchronization constraint and interconnections in quantum-dot cellular automata

Quantum-dot Cellular Automata (QCA) is an emerging nanotechnology with remarkable performance and energy efficiency. Computation and information transfer in QCA are based on field forces rather than electric currents. As a consequence, new strategies are required for design automation approaches in order to cope with the arising challenges. One of these challenges is the transport of information, which is affected by two particularities of the QCA technology. First, information flow in QCA is controlled by external clocks, and second, QCA is a planar technology in which gates, as well as interconnections, are mostly located in the same layer. The former demands proper synchronization already during the circuit design phase, while the latter results in high area costs for interconnections. This work focuses on both constraints and discusses its impact on the implementation of QCA circuits. Further, the concept of local and global synchronicity in QCA circuits is explored. The obtained results indicate that relaxing the global synchronicity constraint can reduce design size by about 70% while the throughput performance declines by similar values. Additionally, it can be shown that the impact of interconnections in QCA, like wires, fan-outs, and crossovers, is indeed substantial. That means, up to 75% of the total area is occupied by interconnections.     

Design and implementation of multiplication algorithm in quantum-dot cellular automata with energy dissipation analysis

The Journal of Supercomputing - QCA is an emerging nanotechnology for the design of digital system circuits based on electron interactions. QCA is used to design nanoscale circuits. Multiplier...     

A genetic strategy to design cellular automata based block ciphers

We propose an evolutionary computation approach to design a fast and secure block cipher using non-uniform second-order cellular automata. We build a flexible block ciphering model that permit the construction of a huge space of possible instances defined each one by a finite set of elementary transition rules. The constructed space is explored using a genetic algorithms strategy in order to find an optimal solution with respect to the strict avalanche criterion used as fitness measurements. The genetically designed cipher is benchmarked experimentally using conventional statistical tests, and shown to have very admissible characteristics leading to a very acceptable level of cryptographic security. Moreover, performances analysis shows that the designed cipher permit to achieve a high encryption/decryption speed, and compete many of the existing standardized ciphers.     

Z-Voter: a novel high-impedance voter for efficient realization of tristate logic in quantum-dot cellular automata technology

The Journal of Supercomputing - Regardless of the technology, the tristate logic is a crucial concept which facilitate bidirectional shared media access as an essential requirement for development...     

Progresses in the analysis of stochastic 2D cellular automata: A study of asynchronous 2D minority

Cellular automata are often used to model systems in physics, social sciences, biology that are inherently asynchronous. Over the past 20 years, studies have demonstrated that the behavior of cellular automata drastically changes under asynchronous updates. Still, the few mathematical analyses of asynchronism focus on 1D probabilistic cellular automata, either on single examples or on specific classes. As for other classic dynamical systems in physics, extending known methods from 1D to 2D systems is a long lasting challenging problem.In this paper, we address the problem of analyzing an apparently simple 2D asynchronous cellular automaton: 2D Minority where each cell, when fired, updates to the minority state of its neighborhood. Our simulations reveal that in spite of its simplicity, the minority rule exhibits a quite complex response to asynchronism. By focusing on the fully asynchronous regime, we are however able to describe completely the asymptotic behavior of this dynamics as long as the initial configuration satisfies some natural constraints. Besides these technical results, we have strong reasons to believe that our techniques relying on defining an energy function from the transition table of the automaton may be extended to the wider class of threshold automata. ²     

A study on learning robustness using asynchronous 1D cellular automata rules

Numerous studies can be found in literature concerning the idea of learning cellular automata (CA) rules that perform a given task by means of machine learning methods. Among these methods, genetic algorithms (GAs) have often been used with excellent results. Nevertheless, few attention has been dedicated so far to the generality and robustness of the learned rules. In this paper, we show that when GAs are used to evolve asynchronous one-dimensional CA rules, they are able to find more general and robust solutions compared to the more usual case of evolving synchronous CA rules.     

Design and simulation of quantum-dot cellular automata serial decimal pipelined processor based on Turing machine model

The quantum-dot cellular automata (QCA) nanoscale computer technology is promising to overcome the limits of the microelectronic CMOS technology. Because the leading role of QCA wires, the serial data transfer/processing is preferable. The financial, Internet of Things, and control computer applications require direct processing of decimal information without representation and conversion errors. Because a QCA wire can be considered as a virtual tape with written binary symbols, a special version of Turing machine model can be used for a QCA computer implementation. Design of a novel QCA serial decimal pipelined processor based on the Turing machine model is presented. The processor uses the run-time tape reconfiguration for arithmetic processing of decimal operands encoded in the 5-bit Johnson-Mobius code. The proposed design demonstrates significant hardware simplification.     

Correction to: Novel design and simulation of reversible ALU in quantum dot cellular automata

The Journal of Supercomputing -     

Structure and reversibility of 2D hexagonal cellular automata

Cellular automata are used to model dynamical phenomena by focusing on their local behavior which depends on the neighboring cells in order to express their global behavior. The geometrical structure of the models suggests the algebraic structure of cellular automata. After modeling the dynamical phenomena, it is sometimes an important problem to be able to move backwards in order to understand it better. This is only possible if cellular automata is reversible. In this paper, 2D finite cellular automata defined by local rules based on hexagonal cell structure are studied. Rule matrix of the hexagonal finite cellular automaton is obtained. The rank of rule matrices representing the 2D hexagonal finite cellular automata via an algorithm is computed. It is a well known fact that determining the reversibility of a 2D cellular automata is a very difficult problem in general. Here, the reversibility problem of this family of 2D hexagonal cellular automata is also resolved completely.     

m-Asynchronous cellular automata: from fairness to quasi-fairness

A new model for the study of asynchronous cellular automata dynamical behavior is introduced with the main purpose of unifying several existing paradigms. The main idea is to measure the set of updating sequences to quantify the dependency of the properties under investigation from them. We propose to use the class of quasi-fair measures, namely measures that satisfy some fairness conditions on the updating sequences. Basic set properties like injectivity and surjectivity are adapted to the new setting and studied. In particular, we prove that they are dimensions sensitive properties (i.e., they are decidable in dimension 1 and undecidable in higher dimensions). A first exploration of dynamical properties is also started, some results about equicontinuity and expansivity behaviors are provided.     

Non-uniform cellular automata based associative memory: Evolutionary design and basins of attraction

This paper presents the synthesis and analysis of a special class of non-uniform cellular automata (CAs) based associative memory, termed as generalized multiple attractor CAs (GMACAs). A reverse engineering technique is presented for synthesis of the GMACAs. The desired CAs are evolved through an efficient formulation of genetic algorithm coupled with the reverse engineering technique. This has resulted in significant reduction of the search space of the desired GMACAs. Characterization of the basins of attraction of the proposed model establishes the sparse network of GMACAs as a powerful pattern recognizer for memorizing unbiased patterns. Theoretical analysis also provides an estimate of the noise accommodating capability of the proposed GMACA based associative memory. An in-depth analysis of the GMACA rule space establishes the fact that more heterogeneous CA rules are capable of executing complex computation like pattern recognition.