PIO I-II tendencies case study. Part 1. Mathematical modeling

In the paper, a study is performed from the perspective of giving a method to reduce the conservatism of the well known PIO (Pilot-Induced Oscillation) criteria in predicting the susceptibility of an aircraft to this very harmful phenomenon. There are three interacting components of a PIO – the pilot, the vehicle, and the trigger (in fact, the hazard). The study, conceived in two parts, aims to underline the importance of human pilot model involved in analysis. In this first part, it is shown, following classical sources, how the LQG theory of control and estimation is used to obtain a complex model of human pilot. The approach is based on the argument, experimentally proved, that the human behaves “optimally” in some sense, subject to his inherent psychophysical limitations. The validation of such model is accomplished based on the experimental model of a VTOL-type aircraft. Then, the procedure of inserting typical saturation nonlinearities in the open loop transfer function is presented. A second part of the paper will illustrate PIO tendencies evaluation by means of a grapho-analytic method

On the synthesis of the pilot optimal control model

The study continues some work of the authors, this time performing a synthesis of optimal control model of the human pilot in systems with input delay, by removing the Padé or Hess approximations characterizing the pilot structural central nervous block and their introduction as a pure delay block. On the one hand, the method ensures a better accuracy of synthesis and on the other hand is advantageous with respect to general results to date for time delay systems since: a) the optimal control law is given explicitly and b) the Riccati equations for the gain matrices do not contain any time advanced or delayed arguments. The approach is stimulated by recent works of M. Basin and his collaborators

Diagnosticul și tratamentul chirurgical al bolii Crohn perianale

Background. Perianal Crohn's disease (pCD) is a marker of severe CD, associating with multiple relapses and operations. Can evolve in isolation (25%) or strike intestinal CD (75%). Correct early diagnosis, timed surgical implications constitute preconditions for success in the treatment of pCD. Objective of the study. Study of clinical, diagnostic and curative peculiarities of perianal Crohn’s disease with the argumentation of surgical indications and performed intervences, analysis of the early and late postoperative results. Material and Methods. Retrospective study (2000-2019), based on the analysis of clinical observation files, results of paraclinical explorations and treatment of 52 patients with pCD. The investigation program was included: examination under anesthesia; endoscopy; imaging modalities (MRI, CT, fistulography, endorectal USG); histological explorations (biopsy, operatory specimens). Results. Based on clinical, radiological, endoscopic and histological data, the definite diagnosis of pCD was possible in 72.7% of cases. Conservative treatment was according to ECCO Protocol (2012) and assured recovering of 31 (59.6%) of assisted patients. Were operated 21 (40.4%) of patients with pCD – drainage of perianal abscess (2), closure of the transphincterian fistula on Seton (6), fistulotomy (2), fistulectomy (3), closure of the recto-vaginal (2) or extrasphincterian (3) fistula with "advancement mucous flap", ileostomy (1), rectal resection with anastomosis (1), procectomy (1). Conclusion. The surgical attitude, individualized in each case, associated with biological therapy (infliximab), allows the essential reduction of relapses (23.8%), postoperative complications (14.3%) and lethality (4.8%). Introducere. Boala Crohn perianală (BCp) constituie un marker al BC severe, asociindu-se cu recidive și operații multiple. Poate evolua izolat (25%) sau greva BC intestinală (75%). Diagnosticul precoce corect, implicațiile chirurgicale oportune constituie premizele succesului în tratamentul BCp. Scopul lucrării. Studierea particularităților clinice, de diagnostic și tratament conservator cu argumentarea indicațiilor operatorii și operației selectate, analiza rezultatelor postoperatorii precoce și tardive în BCp. Material și Metode. Studiul retrospectiv (2000-2019), bazat pe analiza fișelor de observație clinică, al rezultatelor explorărilor paraclinice și tratamentului medico-chirurgical al 52 de bolnavi cu BCp. Programul de investigații a inclus: examinare sub anestezie; endoscopie; modalități imagistice (RMN, TC, fistulografie, USG endorectală); examen histologic (bioptate, piese operatorii). Rezultate. În baza datelor clinice, radiologice, endoscopice și histologice, diagnosticul cert al BCp a fost posibil în 72.7% cazuri. Tratamentul conservator a fost conform ECCO Protocol (2012) și s-a dovedit a fi efectiv în 31 (56.6%) cazuri. Au fost operați 21 (40.4%) bolnavi cu BCp – drenajul abcesului perianal (2), închiderea fistulei transfincteriene pe Seton (6), fistulotomie (2), fistulectomie (3), închiderea fistulei recto-vaginale (2) sau extrasfincteriene (3) cu lambou mucos «de avansare», ileostomie (1), rezecție rectală cu anastomoză (1), proctectomie (1). Concluzii. Atitudinea medicochirurgicală, individualizată la fiecare caz, asociată cu terapie biologică (infliximab), permite reducerea esențială a recidivelor (23.8%), a complicațiilor (14.3%) și a letalității postoperatorii (4.8%)

Intelligent control of HVAC systems. Part I: Modeling and synthesis

This is the first part of a work on intelligent type control of Heating, Ventilating and Air-Conditioning (HVAC) systems. The study is performed from the perspective of giving a unitary control method to ensure high energy efficiency and air quality improving. To illustrate the proposed HVAC control technique, in this first part it is considered as benchmark problem a single thermal space HVAC system. The construction of the mathematical model is performed only with a view to obtain a framework of HVAC intelligent control validation by numerical simulations. The latter will be reported in a second part of the study

Studies regarding production and use of organic medicinal and spice plants

Romania has tradition and a great potential to improve its production of medicinal and spice plants. Whether this important potential is used within the organic farming system, this will create new opportunities for small farmers. Medicinal and spice plants grown within the organic farming system could have a significant contribution to the following aspects: clean agriculture, new technologies, healthy products, environmental protection and conservation of the natural resources. In Romania, there are possibilities to produce and obtained organic medicinal and spice plants products