Terms Of Set-points Research Articles

L’étude ADVANCE en questions

The symptoms of secondary hyperparathyroidism (SHPT) were substantially changed by the availability of cinacalcet (CC). The recent ADVANCE study, which was a prospective randomized trial comparing two treatment strategies—CC plus low doses of calcitriol analogues (CA) versus higher doses of CA without CC—reports the absence of difference in the primary endpoint, i.e. coronary artery calcification score progression after 12months. The progression of coronary calcification was related to the initial hypercalcemia and hyperphosphataemia, and low serum PTH level. What was the rationale for defining SHPT with only serum PTH value of more than 300pg/mL or more than 150pg/mL associated with a high Ca×P product? Why was this coronary score chosen as the primary endpoint and why was a seemingly short observational period used? Is it correct to consider all forms of SHPT equivalent in terms of set point, response to conventional treatment, or vascular and bone consequences? Why are the biological values of patients not provided? Were the CAs, dialysate calcium, and PTH assay values really equal? Why were only calcium-based phosphate binders used? The main controversial point of the study was to consider all HPT cases as equivalent and able to be treated by one fixed strategy. Therefore, the nephrologist community should conduct relevant independent studies in order to improve the diagnosis and treatment of SHPT.

Fuzzy self-tuning of PID controllers

Abstract This paper presents a novel fuzzy self-tuning PID control scheme for regulating industrial processes. The essential idea of the scheme is to parameterize a Ziegler-Nichols-like tuning formula by a single parameter α, then to use an on-line fuzzy inference mechanism to self-tune the parameter. The fuzzy tuning mechanism, with process output error and error rate as its inputs, adjusts α in such a way that it speeds up the convergence of the process output to a set-point y r , and slows down the divergence trend of the output from y r . A comparative simulation study on various processes, including a second-order process, processes with long dead-time and non-minimum phase processes, shows that the performance of the new scheme improves considerably, in terms of set-point and load disturbance responses, over the PID controllers well-tuned using both the classical Ziegler-Nichols formula and the more recent Refined Ziegler-Nichols formula.