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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)
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)
In this paper an algorithm to optimize switching sequences for a class of switched linear problems is presented. The algorithm searches for solutions which are arbitrarily close to optimal – finding the optimal solution does often require a much larger search. Both deterministic and stochastic problems are considered.
Long-termmemorymotion-compensated prediction extends the spatial displacement utilized in block-based hybrid video coding by a frame reference parameter permitting the use of decoded frames of some seconds accommodated in a sliding window over time. This extension of the motion search range signi cantly increases the motion-compensated prediction gain.(More)
Heme oxygenase has been considered to be involved in the predominant pathway of heme degradation in vivo. However, alternative pathways involving cytochrome P-450 reductase, and lipid peroxidation, have previously been demonstrated in vitro, and studies with cultured rat hepatocytes were interpreted to show a majority of endogenous hepatic heme breakdown by(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)
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 developed a microassay for heme oxygenase, in which bilirubin (BR) production was measured by HPLC, and compared it to previously reported spectrophotometric methods. The microassay required as little as 5 mg wet human, rat, or chick embryo liver. Using the HPLC assay, values for heme oxygenase activity in extracts (10,000 g supernatant) of normal human(More)