Logic functions

Non-linear system may be used to process information. The implementation of logic functions and computations has been reviewed by Helmfelt and Ress [62]. As a typical example, the logical network built of cyclic enzymatic reactions which are coupled with enzymatic reactions via common reagents has been investigated [63]. 

Field and M. Burger (eds) Oscillations and Chemical Waves in Chemical Systems, WUey, New York, 1985. 

Goldheter, Biochemical Oscillations and CeUnlar Rhythms, The Molecular Phases of Periodic and Chaotic Behaviom, Cambridge University Press, London 1996. 

Chance, E.K. Pye, A.K. Ghosh and B. Hess, Biological and Biochemical OscUlatorys, Academic Press, London and New York, 1973. 

Nicolis and I. Prigogine, Self-Organization in Non-Fquilibrium Systems, John Wiley and Sons, New York, 1977, p. 93. 

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Programmable Logic Controllers The programmable logic controller (PLC) originated as a solid-state replacement for the hardwired relay control panel and was first used in the automotive indus-tiy for discrete manufacturing control. Today, PLCs are used to implement Boolean logic functions, timers, counters, and some math functions and PID control. PLCs are often used with on/off process control valves. 

Consider a logic gate with 3-iiiput and 3-output lines. Edward Fredkin, motivated by a deep conviction in a fundamental connection between a discrete, finite physics and reversible computation [wrightSS], discovered a simple universal 3-input/ 3-output logic function that now bears his name [fredkin82]. 

Since two input/output lines do not suffice to construct an arbitrary reversible logical function (see discussion in section 6.4.2), Feynman also introduces the three-... 

Miiller, F. The Flavin Redox-System and Its P -logical Function. 108, 71-107 (1983). 

The primitive functions These comprise the various mathematical and logical operations that the program may need. They will usually include mathematical functions such as + -, /, and, logical functions, programming constructs, such as loops, and possibly other mathematical functions, such as trigonometric, exponential, and power functions. 

Stadler R, Ami S, Joachim C, Forshaw M (2004) Integrating logic functions inside a single molecule. Nanotechnology 15(4) S115—S121... 

Fig. 22 (a) Model system able to perform six different logic functions depending on its structural parameters e and k. Current intensity passing through this system for e = k = 0 eV, v = 5 meV, and a and [1 going from 0 to 1 eV. The variation of the current respects the XOR truth table a strong current is obtained for = 0=1 and =1 = 0 and a weak one for = 0 = 0 and =1 = 1. Due to the stable plateaux at the comers of the map, this device naturally corrects small deviations in the inputs that lead to even smaller deviations in the output... 

The flat tire example is pictured using a fault tree logic diagram, shown in Figure 11-12. The circles denote basic events and the rectangles denote intermediate events. The fishlike symbol represents the OR logic function. It means that either of the input events will cause the output state to occur. As shown in Figure 11 -12, the flat tire is caused by either debris on the road or tire failure. Similarly, the tire failure is caused by either a defective tire or a worn tire. 

Second, determine the major events that contribute to the top event. Write these down as intermediate, basic, undeveloped, or external events on the sheet. If these events are related in parallel (all events must occur in order for the top event to occur), they must be connected to the top event by an AND gate. If these events are related in series (any event can occur in order for the top event to occur), they must be connected by an OR gate. If the new events cannot be related to the top event by a single logic function, the new events are probably improperly specified. Remember, the purpose of the fault tree is to determine the individual event steps that must occur to produce the top event. 

Now consider any one of the new intermediate events. What events must occur to contribute to this single event Write these down as either intermediate, basic, undeveloped, or external events on the tree. Then decide which logic function represents the interaction of these newest events. 

ESD system performance is measured in terms of reliability and availability. Reliability is the probability a component or system will perform its logic function under stated operating conditions for a defined time period. Availability is the probability or mean fraction of total time that a protective component or system is able to function on demand. Increased reliability does not necessarily increase availability. 

Reliability - The probability that a component or system will perform its defined logic function under the stated conditions for a defined period of time. 

Chemically induced dethreading/rethreading in similar pseudorotaxane systems has been shown to behave according to the XOR logic function.1251... 

A special kind of random noise, pseudo random noise, has the special property of not being really random. After a certain time interval, a sequence, the same pattern is repeated. The most suitable random input function used in CC is the Pseudo Random Binary Sequence (PRBS). The PRBS is a logical function, that has the combined properties of a true binary random signal and those of a reproducible deterministic signal. The PRBS generator is controlled by an internal clock a PRBS is considered with a sequence length N and a clock period t. It is very important to note that the estimation of the ACF, if computed over an integral number of sequences, is exactly equal to the ACF determined over an infinite time. 

Based on the results presented, the basic logic functions NOT, AND, OR can be built using monocyclic or dicyclic enzyme systems. 

A. Hjelmfelt and J. Ross, Implementation of logic functions and computations by chemical kinetics, Physica D Nonlinear Phenomena, 84, 180-193 (1995). 

Verbal, logical functions No clear effects No data... 

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