Search results for "BIF"
showing 10 items of 539 documents
Control of a fermentator for the aerobic growth of saccharomyces cerevisiae by an adaptive type-2 fuzzy logic controller
2008
I controllori a logica fuzzy (FLCs) costituiscono una facile alternativa al controllo di sistemi che hanno un comportamento fortemente non lineare, facendo uso di fuzzy sets e di una logica fuzzy del 1° tipo. A dispetto della loro popolarità però, la ricerca ha mostrato come FLCs di 1° tipo, abbiano difficoltà a gestire e a minimizzare le incertezze presenti in un sistema. Una più grande complessità dei sistemi a logica fuzzy di 2° tipo rispetto quelli del 1° tipo, permette di gestire e conseguentemente di minimizzare gli effetti di una varietà di incertezze che non può essere direttamente gestita da FLS del 1° tipo. In questo lavoro si è considerato l’uso di un FLS del 2° tipo per il contr…
Control of a nonlinear continuous bioreactor with bifurcation by a type-2 fuzzy logic controller
2008
The object of this paper is the application of a type-2 fuzzy logic controller to a nonlinear system that presents bifurcations. A bifurcation can cause instability in the system or can create new working conditions which, although stable, are unacceptable. The only practical solution for an efficient control is the use of high performance controllers that take into account the uncertainties of the process. A type-2 fuzzy logic controller is tested by simulation on a nonlinear bioreactor system that is characterized by a transcritical bifurcation. Simulation results show the validity of the proposed controllers in preventing the system from reaching bifurcation and instable or undesirable s…
Control of a non-isothermal continuous stirred tank reactor by a feedback–feedforward structure using type-2 fuzzy logic controllers
2011
A control system that uses type-2 fuzzy logic controllers (FLC) is proposed for the control of a non-isothermal continuous stirred tank reactor (CSTR), where a first order irreversible reaction occurs and that is characterized by the presence of bifurcations. Bifurcations due to parameter variations can bring the reactor to instability or create new working conditions which although stable are unacceptable. An extensive analysis of the uncontrolled CSTR dynamics was carried out and used for the choice of the control configuration and the development of controllers. In addition to a feedback controller, the introduction of a feedforward control loop was required to maintain effective control…
Borderline intellectual functioning and parental stress: An italian case-control study
2016
Introduction: Borderline intellectual functioning (BIF) children comprises a group of subjects whit intelligence quotient (IQ) ranging 71-85, with a prevalence about 13.6%. Several studies pinpointed the role of parenting on BIF management. Aim of present study was evaluating with objective and validated tool the parental stress rate in mothers of an Italian sample of BIF children. Materials and methods: 26 BIF children (20 males and 6 females) aged 6-10 years (mean age 10.36± 2.03), according to DSM-5 criteria, and 53 (42 males and 11 females) typical developing children (mean age 10.58 ± 1.97) were recruited for present study. Mothers of all enrolled children underwent an evaluation with …
Positive and nodal solutions for nonlinear nonhomogeneous parametric neumann problems
2020
We consider a parametric Neumann problem driven by a nonlinear nonhomogeneous differential operator plus an indefinite potential term. The reaction term is superlinear but does not satisfy the Ambrosetti-Rabinowitz condition. First we prove a bifurcation-type result describing in a precise way the dependence of the set of positive solutions on the parameter λ > 0. We also show the existence of a smallest positive solution. Similar results hold for the negative solutions and in this case we have a biggest negative solution. Finally using the extremal constant sign solutions we produce a smooth nodal solution.
COLORECTAL CANCER AND INFLAMMATORY BOWEL DISEASES: EFFECTS ON DIET AND ANTIOXIDANTS
2017
It is well established that oxidative stress is common in inflammatory bowel diseases (IBDs). Accordingly, antioxidants are recommended for treatment. The aim of this study is to compare the effects of antioxidants contained in the various types of tea on symptoms and evolution of IBD and colorectal cancer (CRC). Analysis of the literature revealed that the theaflavin-3, 30-digallate (TFDG) contained in black tea, and epigallocatechin-3-O-gallate (EGCG) contained in green tea have protective effects against oxidative stress. Moreover, these substances are involved in many biochemical processes responsible for inflammation and proliferation of cancer cells. It is documented that both TFDG an…
LE DISRAFIE SPINALI CISTICHE: casistica e attuali orientamenti terapeutici in età neonatale
1990
Gli Autori riportano la loro esperienza sul trattamento delle disrafie spinali cistiche in età neonatale e, dopo una revisione della letteratura, ne sottolineano gli aspetti deontologici, clinici e terapeutici
A proof of bistability for the dual futile cycle
2014
Abstract The multiple futile cycle is an important building block in networks of chemical reactions arising in molecular biology. A typical process which it describes is the addition of n phosphate groups to a protein. It can be modelled by a system of ordinary differential equations depending on parameters. The special case n = 2 is called the dual futile cycle. The main result of this paper is a proof that there are parameter values for which the system of ODE describing the dual futile cycle has two distinct stable stationary solutions. The proof is based on bifurcation theory and geometric singular perturbation theory. An important entity built of three coupled multiple futile cycles is…
Links and Bifurcations in Nonsingular Morse–Smale Systems
1997
Wada's theorem classifies the set of periodic orbits in NMS systems on S3 as links, that can be written in terms of six operations. This characterization allows us to study the topological restrictions that links require to suffer a given codimension one bifurcation. Moreover, these results are reproduced in the case of NMS systems with rotational symmetries, introducing new geometrical tools.
Socioemotional Wealth and Networking in the Internationalisation of Family SMEs
2021
In internationalisation processes, international expansion exposes family SMEs to external networking and the risks such expansion entails, and perceived threats to their socioemotional wealth (SEW) might restrain their willingness to take these actions. However, very few studies measure SEW and associate it with internationalisation. Considering SEW preservation’s prominence in family SMEs and SMEs’ heavy dependence on networking during internationalisation, we hypothesise that SEW preservation has a negative association and networking has a positive association with the family SMEs’ degree of internationalisation (DOI). We reconstruct four SEW constructs that carry significance for family…