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The paper presents two recently developed, MATLAB-based analysis tools for real-time control systems. The first tool, called JITTERBUG, is used to compute a performance criterion for a control loop under various timing conditions. The tool makes it easy to quickly judge how sensitive a controller is to implementation effects such as slow sampling, delays,(More)
—This note considers offline optimization of a switching sequence for a given finite set of linear control systems, together with joint optimization of control laws. A linear quadratic full information criterion is optimized and dynamic programming is used to find an optimal switching sequence and control law. The main result is a method for efficient(More)
The article presents two MATLAB-based tools for analysis and simulation of real-time control systems: JITTERBUG and TRUETIME. JITTERBUG allows the user to compute a quadratic performance criterion for a linear control system under various timing conditions. The control system is described using a number of continuous-and discrete-time linear systems. A(More)
Based on recent advances in control theory, we propose the notion of jitter margin for periodic control tasks. The jitter margin is defined as a function of the amount of constant delay in the control loop, and it describes how much additional time-varying delay can be tolerated before the loop goes unstable. Combined with scheduling theory, the jitter(More)
We describe a rapid, reverse-phase HPLC procedure for separating and quantifying tetrapyrroles of biological interest. This procedure uses a 5-micron C18 column and the mobile phase is ammonium phosphate (pH 3.5) with a methanol gradient that is increased from 61 to 100%. Detection is by absorbance at 405 nm or by fluorescence. Porphyrins, heme, and the(More)
We studied drug- and metal-mediated increases in activity of haem oxygenase, the rate-controlling enzyme for haem breakdown, in chick-embryo hepatocytes in ovo and in primary culture. Phenobarbitone and phenobarbitone-like drugs (glutethimide, mephenytoin), which are known to increase concentrations of an isoform of cytochrome P-450 in chick-embryo(More)