Читать книгу Handbook of Intelligent Computing and Optimization for Sustainable Development - Группа авторов - Страница 51

The activity of the brain resembles the computer as it functions as an input-output device. The basic design of digital computer follows Boolean algebra. McCulloch and Pitts [1] presented their view on the possibility of the brain to use Boolean algebra. As the input and output of the neural model are binary numbers, thus the researcher do proposed that multilayer neural network can implement the basic logic gates, i.e., AND, OR, and NOT. This can be achieved by appropriately choosing the weights. Complex Boolean circuits can be constructed by designing properly connected architecture by neurons.

 • AND Gate: The truth table for AND gate is represented by Table 2.1.Table 2.1 Truth table for AND gate.Input (ix)Input (iy)Output (y)000100010111The function for implementation of AND gate is represented by Equation (2.16).(2.16)where b ≡ bias value and 1 < b < 2;g(.) ≡ step function;ix, iy ≡ input values and ix, iy ∈ {0, 1};y ≡ output value and y ∈ {0, 1}.

 • OR Gate: The truth table for OR gate is represented by Table 2.2.Table 2.2 Truth table for OR gate.Input (ix)Input (iy)Output (y)000011101111The function for implementation of OR gate is represented by Equation (2.17).(2.17)where b ≡ bias value and 0 < b < 1;g(.) ≡ step function;ix, iy ≡ input values and ix, iy ∈ {0, 1};y ≡ output value and y ∈ {0, 1}.

 • NOT Gate: The truth table for NOT gate is represented by Table 2.3.Table 2.3 Truth table for NOT gate.Input (ix)Output (y)0110The function for implementation of NOT gate is represented by Equation (2.18).(2.18)where b ≡ bias value and 0 < b < 1;g(.) ≡ step function;ix ≡ input value and ix ∈ {0, 1};y ≡ output value and y ∈ {0, 1}.

In this section, we focus on the design strategy of logic gates which has been developed using the secondary structures of DNA molecules. These DNA logic gates are the pillars of logic circuits which are needed to design a competent DNA computer in near future.