Research on output feedback control

In designing fixed order compensators, an output feedback formulation has been adopted by suitably augmenting the system description to include the compensator states. However, the minimization of the performance index over the range of possible compensator descriptions was impeded due to the nonuniqueness of the compensator transfer function. A controller canonical form of the compensator was chosen to reduce the number of free parameters to its minimal number in the optimization. In the MIMO case, the controller form requires a prespecified set of ascending controllability indices. This constraint on the compensator structure is rather innocuous in relation to the increase in convergence rate of the optimization. Moreover, the controller form is easily relatable to a unique controller transfer function description. This structure of the compensator does not require penalizing the compensator states for a nonzero or coupled solution, a problem that occurs when following a standard output feedback synthesis formulation

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Neural network based automatic limit prediction and avoidance system and method

A method for performance envelope boundary cueing for a vehicle control system comprises the steps of formulating a prediction system for a neural network and training the neural network to predict values of limited parameters as a function of current control positions and current vehicle operating conditions. The method further comprises the steps of applying the neural network to the control system of the vehicle, where the vehicle has capability for measuring current control positions and current vehicle operating conditions. The neural network generates a map of current control positions and vehicle operating conditions versus the limited parameters in a pre-determined vehicle operating condition. The method estimates critical control deflections from the current control positions required to drive the vehicle to a performance envelope boundary. Finally, the method comprises the steps of communicating the critical control deflection to the vehicle control system; and driving the vehicle control system to provide a tactile cue to an operator of the vehicle as the control positions approach the critical control deflections

Technical and economic analysis of the reconversion of an existing biogas plant to biomethane production: a case study.

The paper deals with the technical and economic analysis of a project aimed at transforming an existing plant, used for the anaerobic digestion of zoo-technical and agroforest biomass and including a CHP system of about 1 MW of electric capacity, into a facility producing bio-methane for automotive and/or stationary power applications. A comparison of different biogas upgrading technologies is performed, aimed at selecting the technology most appropriate to the size and typology of application under evaluation. Similarly, an analysis is performed to evaluate the opportunity of installing a bio-methane liquefaction facility, to simplify the management and transportation of the fuel, to be used in vehicles. The economic analysis is performed by considering the incentives presently available in Italy for bio-methane producers. Different scenarios are analyzed and discussed, and it was concluded that the conversion of the existing plant into a facility to produce bio-methane to be liquified and sold as fuel for vehicles represents at this moment a very attractive and profitable option

Flettner Rotor Concept for Marine Applications: A Systematic Study

The concept of Flettner rotor, a rotating cylinder immersed in a fluid current, with a top-mounted disk, has been analyzed by means of unsteady Reynolds averaged Navier-Stokes simulations, with the aim of creating a suitable tool for the preliminary design of the Flettner rotor as a ship's auxiliary propulsion system. The simulation has been executed to evaluate the performance sensitivity of the Flettner rotor with respect to systematic variations of several parameters, that is, the spin ratio, the rotor aspect ratio, the effect of the end plates, and their dimensions. The Flettner rotor device has been characterized in terms of lift and drag coefficients, and these data were compared with experimental trends available in literature. A verification study has been conducted in order to evaluate the accuracy of the simulation results and the main sources of numerical uncertainty. All the simulation results were used to achieve a surrogate model of lift and drag coefficients. This model is an effective mathematical tool for the preliminary design of Flettner rotor. Finally, an example of assessment of the Flettner rotor performance as an auxiliary propulsion device on a real tanker ship is reported

Correction to: Diffusion, outcomes and implementation of minimally invasive liver surgery: a snapshot from the I Go MILS (Italian Group of Minimally Invasive Liver Surgery) Registry

A technical error led to incorrect rendering of the author group in this article. The correct authorship is as follows: Luca Aldrighetti, Francesca Ratti, Umberto Cillo, Alessandro Ferrero, Giuseppe Maria Ettorre, Alfredo Guglielmi, Felice Giuliante, Fulvio Calise on behalf of the Italian Group of Minimally Invasive Liver Surgery (I GO MILS) The collaborators are: Raffaele Dalla Valle, AOU Parma, Parma; Vincenzo Mazzaferro, Istituto Nazionale Tumori, Milano; Elio Jovine, Ospedale Maggiore, Bologna; Luciano Gregorio De Carlis, Ospedale Niguarda Ca\u2019 Granda, Milano; Ugo Boggi, AOU Pisana, Pisa; Salvatore Gruttadauria, ISMETT, Palermo; Fabrizio Di Benedetto, AOU Policlinico di Modena, Modena; Paolo Reggiani, Ospedale Maggiore Policlinico, Milano; Stefano Berti, Ospedale Civile S.Andrea, La Spezia; Graziano Ceccarelli, Ospedale San Donato, Arezzo; Leonardo Vincenti, AOU Consorziale Policlinico, Bari; Giulio Belli, Ospedale SM Loreto Nuovo, Napoli; Guido Torzilli, Istituto Clinico Humanitas, Rozzano; Fausto Zamboni, Ospedale Brotzu, Cagliari; Andrea Coratti, AOU Careggi, Firenze; Pietro Mezzatesta, Casa di Cura La Maddalena, Palermo; Roberto Santambrogio, AO San Paolo, Milano; Giuseppe Navarra, AOU Policlinico G. Martino, Messina; Antonio Giuliani, AO R.N. Cardarelli, Napoli; Antonio Daniele Pinna, Policlinico Sant\u2019Orsola Malpighi, Bologna; Amilcare Parisi, AO Santa Maria di Terni, Terni; Michele Colledan, AO Papa Giovanni XXIII, Bergamo; Abdallah Slim, AO Desio e Vimercate, Vimercate; Adelmo Antonucci, Policlinico di Monza, Monza; Gian Luca Grazi, Istituto Nazionale Tumori Regina Elena, Roma; Antonio Frena, Ospedale Centrale, Bolzano; Giovanni Sgroi, AO Treviglio-Caravaggio, Treviglio; Alberto Brolese, Ospedale S.Chiara, Trento; Luca Morelli, AOU Pisana, Pisa; Antonio Floridi, AO Ospedale Maggiore, Crema; Alberto Patriti, Ospedale San Matteo degli Infermi, Spoleto; Luigi Veneroni, Ospedale Infermi AUSL Romagna, Rimini; Giorgio Ercolani, Ospedale Morgagni Pierantoni, Forl\uec; Luigi Boni, AOU Fondazione Macchi, Varese; Pietro Maida, Ospedale Villa Betania, Napoli; Guido Griseri, Ospedale San Paolo, Savona; Andrea Percivale, Ospedale Santa Corona, Pietraligure; Marco Filauro, AO Galliera, Genova; Silvio Guerriero, Ospedale San Martino, Belluno; Giuseppe Tisone, Policlinico Tor Vergata, Roma; Raffaele Romito, AOU Maggiore della Carit\ue0, Novara; Umberto Tedeschi, AOU Integrata Verona, Verona; Giuseppe Zimmitti, Fondazione Poliambulanza, Brescia

Surgical Approach for Long-term Survival of Patients With Intrahepatic Cholangiocarcinoma: A Multi-institutional Analysis of 434 Patients.

OBJECTIVES To examine the outcomes of a hepatectomy for intrahepatic cholangiocarcinoma (IHC) and to clarify the prognostic impact of a lymphadenectomy and the surgical margin. Large series of patients who were surgically treated for IHC are scarce. Thus, prognostic factors and long-term survival after resection of IHC remain uncertain. DESIGN Prospective study of patients who were surgically treated for IHC. Clinicopathologic, operative, and long-term survival data were analyzed. SETTING Prospectively collected data of all consecutive patients with pathologically confirmed IHC who had undergone liver resection with a curative intent at 1 of 16 tertiary referral centers were entered into a multi-institutional registry. PATIENTS All consecutive patients who underwent a hepatectomy with a curative intent for IHC (1990-2008) were identified from a multi-institutional registry. RESULTS A total of 434 patients were included in the analysis. Most patients underwent a major or extended hepatectomy (70.0%) and a systematic lymphadenectomy (62.2%). The incidence of lymph node metastases (overall, 36.9%) increased with increased tumor size, with 24.4% of patients with a small IHC (diameter 643 cm) having N1 disease. Almost one-third of patients required an additional major procedure to obtain a R0 resection in 84.6% of the cases. In these patients, the median time of survival was 39 months, and the 5-year survival rate was 39.8%. Lymph node metastases (hazard ratio, 2.21; P < .001), multiple tumors (hazard ratio, 1.50; P = .009), and an elevated preoperative cancer antigen 19.9 level (hazard ratio, 1.62; P = .006) independently predicted an adverse prognosis. Conversely, survival was not influenced by the width of a negative resection margin (P = .61). The potential survival benefit of a lymphadenectomy was assessed with the therapeutic value index, which was calculated to be 5.9 points. CONCLUSIONS Survival rates after a hepatectomy with a curative intent for IHC at tertiary referral centers exceed the survival rates reported in most study series in single institutions, which strengthens the value of an aggressive approach to radical resection. Lymph node metastases and multiple tumors are associated with decreased survival rates, but they should not be considered selection criteria that prevent other patients from undergoing a potentially curative resection. Lymphadenectomy should be considered for all patients

Hydrogel Cross-Linking via Thiol-Reactive Pyridazinediones

Thiol-reactive Michael acceptors are commonly used for the formation of chemically cross-linked hydrogels. In this paper, we address the drawbacks of many Michael acceptors by introducing pyridazinediones as new cross-linking agents. Through the use of pyridazinediones and their mono- or dibrominated analogues, we show that the mechanical strength, swelling ratio, and rate of gelation can all be controlled in a pH-sensitive manner. Moreover, we demonstrate that the degradation of pyridazinedione-gels can be induced by the addition of thiols, thus providing a route to responsive or dynamic gels, and that monobromo-pyridazinedione gels are able to support the proliferation of human cells. We anticipate that our results will provide a valuable and complementary addition to the existing toolkit of cross-linking agents, allowing researchers to tune and rationally design the properties of biomedical hydrogels

Evaluación del target strength de juveniles de atún rojo (Thunnus thynnus) en jaulas marinas

En los últimos años, el Instituto Español de Oceanografía (IEO) ha maximizado sus esfuerzos en desarrollar mecanismos para la cría en cautividad del atún rojo (Thunnus thynnus), cuyo ciclo completo está a punto de cerrarse. Este trabajo presenta los resultados obtenidos tras realizar mediciones acústicas con una ecosonda científica y un transductor split-beam en jaulas marinas donde los atunes, nacidos en cautividad, se separan en tres tamaños. La combinación de los datos acústicos y de los muestreos biométricos (obtenidos ópticamente) permite establecer una relación entre la longitud de los peces y el valor del target stregth (TS) devuelto por dichos peces.In recent years, the Spanish Institute of Oceanography (IEO) has maximized its efforts on developing mechanisms for the breeding of bluefin tuna (Thunnus thynnus), whose complete cycle is near to be closed. In this paper, acoustic measurements performed on young tuna cages (with scientific echosounder and split-beam transducer) are presented. Tuna housed in the cages were born in captivity and they are divided in three cages according to their size. The combination of the acoustic and biometric data (obtained with stereoscopic system) allow to establish a relationship between representative tuna length in each cage and the target strength (TS)