Exploiting special problem structure when reliably investigating the solution of systems of IVPs and DDEs

2016 ◽  
Author(s):  
W. H. Enright
Author(s):  
J. R. Jagannatha Rao ◽  
Panos Y. Papalambros

Abstract Decomposition strategies are used in a variety of practical design optimization applications. Such decompositions are valid, if the solution of the decomposed problem is in fact also the solution to the original one. Conditions for such validity are not always obvious. In the present article, we develop conditions for two-level parametric decomposition under which: (1) isolated minima at the two levels imply an isolated minimum for the original problem; (2) necessary conditions at the two-levels are equivalent to the necessary conditions for the original problem; and, (3) a descent algorithm for computing Karush-Kuhn-Tucker points in decomposition formulations is globally convergent. Since no special problem structure is assumed, the results are general and could be used to evaluate the suitability of a variety of approaches and algorithms for decomposition strategies.


1967 ◽  
Vol 113 (501) ◽  
pp. 813-822 ◽  
Author(s):  
Örnulv Ödegård

My choice of Kraepelin as a point of departure for this lecture has definite reasons. If one wants to stay within the field of clinical psychiatry (as opposed to psychiatric history), that is as far back as one can reasonably go. By this no slight is intended upon the pre-Kraepelinian psychiatrists. For our topic Henry Maudsley would indeed have been a most appropriate starting point, and by no means for reasons of courtesy. His general point of view is admirably sound as a basis for the scientific study of prognosis in psychiatry. I quote: “There is no accident in madness. Causality, not casualty, governs its appearance in the universe, and it is very far from being a good and sufficient practice simply to mark its phenomena and straightway to pass on as if they belonged not to an order but to a disorder of events that called for no explanation.” On the special problem of prognosis he shows his clinical acumen by stating that the outlook is poor when the course of illness is insidious, but this only means that these cases develop their psychoses on the basis of mental deviations which go very far back in the patient's life, so that in fact they are generally in a chronic stage at the time of their first admission to hospital. Here he actually corrects a mistake which is still quite often made. He shows his dynamic attitude when he says that prognosis is to a large extent modified by external conditions, in particular by the attitude of friends and relatives. Maudsley's dynamic reasoning was limited by the narrow framework of the degeneration hypothesis of those days. He had a sceptical attitude towards classification, which he regarded as artificial and dangerously pseudo-exact. His own classification was deliberately provisional, with very wide groups. He held that a description of various sub-forms of chronic insanity was useless, as it would mean nothing but a tiresome enumeration of unconnected details.


1968 ◽  
Vol 39 (3) ◽  
pp. 698-715 ◽  
Author(s):  
H. W. Israel ◽  
M. M. Salpeter ◽  
F. C. Steward

Cultured carrot explants, stimulated to grow rapidly in a medium containing coconut milk, were labeled with radioactive proline. After an initial period of absorption (8 hr for proline-3H; 24 hr for proline-14C) the tissue was allowed to grow for a further period of 6 days in a similar medium free from the radioactivity. Samples were prepared for electron microscopy and radioautography at the end of the absorption period and also after the further growth. The distribution of the products from the radioactive proline in the cells is shown by high-resolution radioautography and is rendered quantitative for the different regions of the cells. The results show that the combined label, which was present in the form of proline and the hydroxyproline derived from it, was all in the protoplasm, not in the cell walls. Any combined label that appeared to be over the cell walls is shown to be due to scatter from adjacent cytoplasmic sites. Initially the radioactivity was concentrated in nuclei, even more so in nucleoli, but it subsequently appeared throughout the ground cytoplasm and was also concentrated in the plastids. The significance of these observations for the general concept of a plant cell wall protein and for the special problem of growth induction in otherwise quiescent cells is discussed.


Cancer ◽  
1956 ◽  
Vol 9 (4) ◽  
pp. 837-841 ◽  
Author(s):  
Orliss Wildermuth ◽  
John C. Evans
Keyword(s):  

2021 ◽  
Vol 1 (2) ◽  
pp. 1-23
Author(s):  
Arkadiy Dushatskiy ◽  
Tanja Alderliesten ◽  
Peter A. N. Bosman

Surrogate-assisted evolutionary algorithms have the potential to be of high value for real-world optimization problems when fitness evaluations are expensive, limiting the number of evaluations that can be performed. In this article, we consider the domain of pseudo-Boolean functions in a black-box setting. Moreover, instead of using a surrogate model as an approximation of a fitness function, we propose to precisely learn the coefficients of the Walsh decomposition of a fitness function and use the Walsh decomposition as a surrogate. If the coefficients are learned correctly, then the Walsh decomposition values perfectly match with the fitness function, and, thus, the optimal solution to the problem can be found by optimizing the surrogate without any additional evaluations of the original fitness function. It is known that the Walsh coefficients can be efficiently learned for pseudo-Boolean functions with k -bounded epistasis and known problem structure. We propose to learn dependencies between variables first and, therefore, substantially reduce the number of Walsh coefficients to be calculated. After the accurate Walsh decomposition is obtained, the surrogate model is optimized using GOMEA, which is considered to be a state-of-the-art binary optimization algorithm. We compare the proposed approach with standard GOMEA and two other Walsh decomposition-based algorithms. The benchmark functions in the experiments are well-known trap functions, NK-landscapes, MaxCut, and MAX3SAT problems. The experimental results demonstrate that the proposed approach is scalable at the supposed complexity of O (ℓ log ℓ) function evaluations when the number of subfunctions is O (ℓ) and all subfunctions are k -bounded, outperforming all considered algorithms.


PEDIATRICS ◽  
1952 ◽  
Vol 9 (4) ◽  
pp. 494-500
Author(s):  
VICTOR A. NAJJAR ◽  
IRVINE MCQUARRIE ◽  
L. EMMETT HOLT ◽  
LYTT I. GARDNER ◽  
RUTH BAKWIN ◽  
...  

The administration of ACTH or 11-oxygenated steroids to animals results in: (a) increased blood sugar and liver glycogen concentrations, partially as a result of decreased glucose oxidation; (b) increased urinary N excretion; (c) increased total body fat, and (d) tendency toward Na retention and K deficit. In clinical studies these findings have been largely confirmed, using indirect technics. Children on long-term treatment with full doses of adrenal hormones present a special problem, since the foregoing metabolic abnormalities cause inhibition of somatic growth. Periodic clinical appraisal of these patients with careful longitudinal measurements, body weight and x-rays for bony maturation are suggested. The importance of a food intake adequate to offset a negative N balance is stressed, as well as the provision of added K to prevent chronic K deficiency. Question: How soon after you start treatment does K deficiency develop? That is. if you are using cortisone. Dr. Gardner: Compared with desoxycorticosterone, cortisone is a relatively weak K depleting agent, and the development of clinically measurable K deficiency on full doses of cortisone may take several weeks or even longer. This variability of K depleting effect may depend to a great extent upon the dietary intake of Na, since K deficit appears to develop much more readily in the presence of adequate or more than adequate Na intake. Chairman Najjar: In bringing this discussion to an end, I would like to repeat some of the highlights presented here. We know now that some cases of hypoglycemia show absence of the alpha cells of the islet tissue of the pancreas. When pancreatic tissue is obtained under circumstances requiring surgical exploration, one must look for the alpha cells. These cells excrete a hormone, heretofore unsuspected, the hyperglycemic hormone. This is in the process of being produced commercially and should be available in the future. This hormone may well have the therapeutic potentialities for those cases, as insulin has for diabetic patients. Cases with glycogen disease may show severe and irreversible hypoglycemia. Some cases show abnormal glycogen and there is a good possibility that a defect in the enzyme system is responsible. Hormones play a significant role in carbohydrate metabolism and, when uncontrolled, may have a deleterious effect as witnessed by the development of Cushing's syndrome following ACTH therapy.


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