Heuristic approaches to the design of a cybernetic electroanalytical instrument

Abstract

The design of a "cybernetic" electroanalytical instrument requires consideration of both heuristic and deterministic procedures. The former brings to bear expert knowledge to obtain a solution at minimum cost. Heuristic knowledge is most conveniently represented in an expert system structure where the knowledge base is separated from the inference procedure. A system design based on PROLOG is described that obtains a solution by a heuristic depth-first search of an AND/OR graph.

Deterministic control in knowledge-based systems: application to the development of a cybernetic analytical instrument

“…The external devices used for a pHstat include a pH meter, a thermistor, and two solenoid-actuated valves for the addition of acid or base. > ie' «i ia' ¡e lee iiia seconds Chart II frame( 1 .control,delay, [v(delay,300)]) frame (2,alarm,red, [v(beep, 102)]) frame (3,alarm,pink,[v(beep, 102)]) frame (4,alarm,green, [v(beep, 102)]) frame (5,alarm,yellow, [v(beep, 102)]) frame(20,control,solenoidO, [v(add_rate, 1) ]) / # solenoidO assign for control #/ frame(21,control,solenoidO,[v(add_rate,3)]) /# of acid #/ frame (22,control,solenoidO, [v(add_rate,5]) frame (23,control,solenoidO, [v(add_rate, 10]) frame(24,control,solenoidO,[v(add_rate,30]) frame(30,control,solenoid 1, [v(add_rate, 1) ]) / # solenoid 1 assign for control #/ frame(31,control,solenoidl,[v(add_rate,3)]) /# of base #/ frame(32, control, solenoid l,[v(add_rate, cond ( 10,anticipated acidic) cond(l 1,temperature >50) cond(12,pH <3.0) cond(14,pH between 3 and 5) cond(15,pH between 5 and 6) cond(16,pH between 6 and 6.5) rulefl,pHstat,actuate acid solenoid with 45 pulses,[22,23,24], [5]) rule(4,pHstat,actuate acid solenoid with 3 pulses,[21], [5]) rule(5,pHstat,actuate acid solenoid with 3 pulses,[21], [6]) rule(6,pHstat,actuate acid solenoid with 3 pulses,[21], [7]) rule(7,pHstat,delay titration,[1,1,1], [7]) rule (8,pHstat,delay rule(20,pHstat,actuate red alarm-acidic, [2], [2,10]) rule(21,pHstat,actuate pink alarm-neutral, [3], [8,16]) rule(22,pHstat,actuate green alarm-alkaline, [4], [1,3]) rule(23,pHstat,actuate yellow alarm-temperature high, [5],[11]) Figure 3a gives the experimental response where the rules (Chart I) for the addition of acid or base are not optimized.…”

“…In a previous paper we discussed the design of a cybernetic instrument, conceived as a knowledge-based (K-B) system in closed-loop interaction with the experimental control functions. 3 The functional parts of the instrument were partitioned into plan, execute, analyze, and refine phases. The plan and refine phases were considered to be heuristic; the execute phase considered to be deterministic and the analyze phase both heuristic and deterministic.…”

“…Scheduling, queuing, and network theories have been devised to maximize the efficiency of one or more procedures by sequencing tasks and allocating resources. [1][2][3] Programming robotic systems to run laboratory procedures efficiently is often both tedious and time-consuming. Furthermore, once an operating robot program is obtained, the programmer is often reluctant to modify it.…”

Chemometrics

“…The second is a development of a cybernetic electroanalytical instrument by Gunasingham which evaluates the results from a given experiment. If unsatisfactory results occur, the instrument will redesign the experimental strategy by performing a heuristic depth-first search of an AND/OR graph (045).…”