Search

A two-stage scheme is introduced to find the large-scale globally optimal model of an interconnected steady-state system having a structure described by an interconnection matrix. Numerical realization of the scheme by using the standard optimization techniques is discussed, and an analysis of the identification accuracy is conducted.

In this paper an attempt is made to combine the problems of the control and modelling of large-scale systems. Starting from the idea of the model-based (open-loop) solution of the two-layer steady-state optimization problem for the noiseless large-scale system, or one corrupted by slow-varying disturbances, an appropriate two-level identification scheme is derived and discussed. The problems connected with its numerical realization are also stated. The considerations are confined to systems with the cascade structure - typical of most production processes - and to the case when the observations of system input/output signals, from which the system model is determined, are noise-free.

The paper deals with time-optimal control of a complex of independent operations having concave models, when the maximum level of total usage of renewable continuously divisible resource is time-variable and piece-wise constant. In the case considered, neither the moments of a step change of the maximum level of resource, nor their amounts in the consecutive time intervals determined by those moments, are known before starting the control, but they become known in the course of control. An algorithm for the solution of this problem (local optimization of a complex of operations) is proposed. For control determined by this algorithm the performance time of a complex of operations is, in general, greater than the minimum performance time of a complex of operations determined for the same problem, assuming that the maximum level of total usage of resource is at every moment known a priori (global optimization of a complex of operations). The concept of a set of reachable states, and convex analysis, are used to formulate a necessary and sufficient condition that local optimization of a complex of operations ensures a global optimization of this complex. Then, using the theory of function equations a full class of models of operations, for which this condition is satisfied, is determined. These are power models with identical exponents. Some properties of the globally optima! control are given.

It is shown that the Anderson - Moore iterative algorithm can be eliminated in the approach used by Eitelberg and Rode (1982) to the optimal output feedback design by the appropriate choice of the reduced model.

The paper deals with the problem of the optimal reduction of linear constant system description. The idea consists in determining a simplified model for which the open-loop model-based control is the best for the real system in the least-squares sense. The necessary conditions for optimal reduced model parameters are derived.

The article presents an overview of the Avalon Pride variety of peach, which is a hardy, disease resistant variety of peach that was initially discovered in the 1980s in a forest in Washington state by Margaret Proud, the daughter of a horticulturist. A discussion of the variety's attributes and growth and care requirements is presented.

The author focuses on cos lettuce, also known as romaine lettuce, which is said to be the oldest lettuce variety in cultivation. According to the author, cos lettuce is known for its flavor and high concentration of vitamins. The author discusses a trial of cos lettuce held by the Royal Horticultural Society (RHS) and also provides information on sowing and planting cos lettuce.

Chiral carbonyl compounds can easily be enantiodifferentiated by the dirhodium method. The rhodium atoms reveal a remarkable selectivity in binding to oxygen atoms, which is of great advantage for discriminating chiral polyoxygenated natural products. Amides are the strongest ligands followed by ketones and esters; ethers and alcohols/phenols are even less effective. This sequence is rationalized by electronic charges at the oxygen atoms, as obtained from density functional calculations.