Construction Of Logic Circuits Research Articles

Optimizing fault tolerance of RAM cell through MUX based modeling and design using symmetries of QCA cells

Extensive research is now being conducted on the design and construction of logic circuits utilizing quantum-dot cellular automata (QCA) technology. This area of study is of great interest due to the inherent advantages it offers, such as its compact size, high speed, low power dissipation, and enhanced switching frequency in the nanoscale domain. This work presents a design of a highly efficient RAM cell in QCA, utilizing a combination of a 3-input and 5-input Majority Voter (MV) gate, together with a 2 × 1 Multiplexer (MUX). The proposed design is also investigated for various faults such as single cell deletion, single cell addition and single cell displacement or misalignment defects. The circuit under consideration has a high degree of fault tolerance. The functionality of the suggested design is showcased and verified through the utilization of the QCADesigner tool. Based on the observed performance correlation, it is evident that the proposed design demonstrates effectiveness in terms of cell count, area, and latency. Furthermore, it achieves a notable improvement of up to 76.72% compared to the present configuration in terms of quantum cost. The analysis of energy dissipation, conducted using the QCAPro tool, is also shown for various scenarios. It is seen that this design exhibits the lowest energy dispersion, hence enabling the development of ultra-low power designs for diverse microprocessors and microcontrollers.

Construction of logic circuit with modular molecular switching strategy based on DNA strand displacement

SummaryAt present, many DNA logic circuits have been successfully constructed. However, advanced complex DNA computing tasks with simple structure, fast response, and modularization still remain a huge challenge. In this paper, molecular switch circuits (MSCs) are constructed based on DNA strand displacement to improve above problems. At first, molecular switch is constructed, which is the basic element for building logic circuits. Next, the functions of AND, OR, Fan‐in, and Fan‐out are realized through switches cascading in series or parallel. Furthermore, switch canvas strategy is explored to obtain the shortest reaction path and highest output concentration for circuits. Finally, a novel strategy of integrating computing module using molecular switches is proposed. Here, we construct a half‐adder, half‐subtractor, and a 9‐bit parity checking circuits to verify its feasibility. Compared with the classical monorail and dual‐track logic circuits, the structure scale is reduced by more than two times, and the DNA strands are decreased by more than four times, which effectively reduces the circuit complexity and raises the reaction speed. The above results show that MSC strategy has a great potential to construct large‐scale DNA circuits and provides a development model for the scalability and modularity of biological computing.

A peculiarity of solving problems of minimization of Boolean functions

Minimization of Boolean functions is mandatory for the construction of logic circuits of digital automata. The result of minimization, in general, can be not one, but several equivalent images of the Boolean function with the smallest number of variables and logical operations with them. However, a possible set of images of the minimal form of a Boolean function is not always are taken i nto account when solving minimization problems. Quite often, the result of minimization results in only one image, while considering that the problem is finally solved. Of course, such a solution is far from complete, it does not provide an opportunity to choose the optimal logic scheme of the digital automaton to be created. The purpose of the work is to justify the need to find all possible representations of the minimal form of the Boolean function. The task was solved by analyzing the minimization of an arbitrary Boolean function. The minimization was carried out analytically according to the Quine algorithm and coordinate using the Veitch diagram. In both cases, matching sets of images of the minimal form of the Boolean function are obtained, regardless of the chosen method of minimization. This testifies to the correctness of the solution to the minimization problem, the purpose of which is to find a set of images of the Boolean function to ensure the possibility of choosing the optimal solution when constructing a logic circuit of a digital automaton. It has been confirmed that the correct solution to the minimization problem is a mandatory image of not one possible function, but a set of images of all possible minimal forms of the Boolean function.

Multifunctional Exo III-assisted scalability strategy for constructing DNA molecular logic circuits.

The construction of logic circuits is critical to DNA computing. Simple and effective scalability methods have been the focus of attention in various fields related to constructing logic circuits. We propose a double-stranded separation (DSS) strategy to facilitate the construction of complex circuits. The strategy combines toehold-mediated strand displacement with exonuclease III (Exo III), which is a multifunctional nuclease. Exo III can quickly recognize an apurinic/apyrimidinic (AP) site. DNA oligos with an AP site can generate an output signal by the strand displacement reaction. However, in contrast to traditional strand displacement reactions, the double-stranded waste from the strand displacement can be further hydrolysed by the endonuclease function of Exo III, thus generating an additional output signal. The DSS strategy allows for the effective scalability of molecular logic circuits, enabling multiple logic computing capabilities simultaneously. In addition, we succeeded in constructing a logic circuit with dual logic functions that provides foundations for more complex circuits in the future and has a broad scope for development in logic computing, biosensing, and nanomachines.

Electrochemical-Based DNA Logic Devices Regulated by the Diffusion and Intercalation of Electroactive Dyes.

Electrochemical-based logic gates are simple to operate, sensitive, controllable, and easy to integrate with silicon-based semiconductor logic devices, showing great application prospects and remaining largely unexplored. Herein, an immobilization-free dual-output electrochemical molecular logic system based on the different diffusivity of electroactive dyes ferrocene (Fc) and methylene blue (MB) toward an indium tin oxide (ITO) electrode under different DNA hybridization reactions was developed. In this system, the hybridization of the catalytic strand IN1 with Fc-modified hairpin DNA H1 triggered an exonuclease III (Exo III) cleavage cycle to obtain free Fc and produce a large number of long double-stranded DNAs via the hybridization chain reaction for intercalating MB, which was previously in the free state. Such a hybridization reaction caused a significant change in the diffusion capacity of MB and Fc toward the ITO electrode, resulting in two electrochemical signals with opposite changes. On this basis, a contrary logic pair library, a parity generator/checker system for differentiating the erroneous bits during data transmission, a parity checker to identify the even/odd natural numbers from 0 to 9, and a series of concatenated logic circuits for meeting the needs of computational complexity were developed. The proposed electrochemical-based molecular logic system greatly expanded the application of the electrochemical method in the construction of logic circuits and provided a conceptual prototype for the development of more advanced and complicated logic devices.

Novel Diarylethene-Based Fluorescent Switching for the Detection of Al3+ and Construction of Logic Circuit.

A novel photochromic diarylethene was synthesized successfully containing a phthalazine unit. Its multistate fluorescence switching properties were investigated by stimulating with UV/vis lights and Al3+/EDTA. The synthesized diarylethene displayed excellent selectivity to Al3+ with a distinct fluorescence change, revealing that it could be used as a sensor for fluorescence identification of Al3+, and a logic circuit was constructed by utilizing this diarylethene molecular platform. Moreover, it also exhibited a high accuracy for the determination of Al3+ in practical water samples.

ASCGP - Automatic System for Construction of Logical Circuits in FPGA using CGP

In this article is introduced a novel framework for the development of an automatic system using a Cartesian Genetic Programming based approach to construct combinational and sequential logic circuits in FPGAs. The paper is comprised of two parts: the first one is based on a hybrid evolutionary algorithm that by means of parameters provided by the user looks for a logical circuit solution, and the second one is a flexible architecture developed in Verilog-HDL language that converts the solution given in the first part into a hardware implementation inside the FPGA. Good results using this hybrid evolutionary approach have been obtained in all the studied cases in relation to others similar studies in the literature. In addition, the generated hardware is able to manage sequential circuits, being this an innovation of the present project in relation to other projects found in the literature, in which almost all of them can only simulate the automatic generation of combinational circuits.

Reconfigurable DNA Nano-Tweezer for the Construction of Logic Circuits

Reconfigurable DNA Nano-Tweezer for the Construction of Logic Circuits

Logic gates based on G-quadruplexes: principles and sensor applications

This review (with 139 refs.) gives a fundamental introduction into the sensors and logic gates based on G-quadruplexes (G4s). G4 characterizes vibrant binding activities and topology diversity, which contribute to the multiple signal output modes (including labeled moieties based on distance changes, label-free outputs by employing fluorescent ligands, G4/hemin DNAzyme with catalyzing activity and colorimetric readout using gold nanoparticles) and versatile design strategies (including target-induced G4 formation/disruption, liberation of blocked G4, split G4 probes, polymerase-assisted amplification and G4/hemin enrichment on sensor surface) of G4s-based methods. Following two important trends in logic gates (application of intelligent detection schemes and logic circuit constructions), specific sections review logic sensors and logic circuits based on G4s with several representative examples. We close this review with conclusions and give a perspective that employment of DNA technologies (such as aptamers, DNA junctions/origami, toehold-mediated strand displacement, enzyme-assisted amplification, metal ion-dependent DNAzymes) and various nanomaterials in G4s-based methods results in quite a large potential in terms of logic detection and construction of logic circuits.

A novel FPGA-programmable switch matrix interconnection element in quantum-dot cellular automata

The Quantum-dot cellular automata (QCA) is a novel nanotechnology, promising extra low-power, extremely dense and very high-speed structure for the construction of logical circuits at a nanoscale. In this paper, initially previous works on QCA-based FPGA’s routing elements are investigated, and then an efficient, symmetric and reliable QCA programmable switch matrix (PSM) interconnection element is introduced. This element has a simple structure and offers a complete routing capability. It is implemented using a bottom-up design approach that starts from a dense and high-speed 2:1 multiplexer and utilise it to build the target PSM interconnection element. In this study, simulations of the proposed circuits are carried out using QCAdesigner, a layout and simulation tool for QCA circuits. The results demonstrate high efficiency of the proposed designs in QCA-based FPGA routing.

Pattern formation in a reaction-advection model with delay: a continuum approach to myxobacterial rippling

We study a one-species-diffusion equation supplemented by a nonlinear saturation term. If this term includes temporal delay, a rich spatio-temporal behavior already at the critical point where the steady homogeneous solution gets unstable is expected. Normal form transformation into a complex Ginzburg-Landau equation shows that the condition for phase turbulence is always fulfilled. As a secondary instability of these chaotic states well ordered spiral waves and targets are found numerically. Here the system shows features well-known from excitable media. Finally we propose the construction of logical circuits by means of a network built up by one-dimensional excitable media.

Formation and propagation of localized states in extended systems

AbstractWe study a one‐species‐diffusion equation supplemented by a nonlinear saturation term. If this term includes temporal delay, a rich spatio‐temporal behavior already at the critical point where the steady homogeneous solution gets unstable is expected. Normal form transformation into a complex Ginzburg‐Landau equation shows that the condition for phase turbulence is always fulfilled. As a secondary instability of these chaotic states well ordered spiral waves and targets are found numerically. Here the system shows features well‐known from excitable media. Finally we propose the construction of logical circuits by means of a network built up by one‐dimensional excitable media.