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Distribution network reconfiguration using feasibility-preserving evolutionary optimization

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Journal of Modern Power Systems and Clean Energy 2019年第3期7卷 589-598页

作者： alberto LANDEROS Slawomir KOZIEL Mohamed FABDEL-FATTAH School of Science and Engineering Reykjavik University101 ReykjavikIceland Faculty of Electronics Telecommunications and InformaticsGdansk University of Technology80-233Gdan′skPoland

Distribution network reconfiguration(DNR) can significantly reduce power losses, improve the voltage profile, and increase the power quality. DNR studies require implementation of power flow analysis and complex optimization procedures capable of handling large combinatorial problems. The size of distribution network influences the type of the optimization method to be applied. Straightforward approaches can be computationally expensive or even prohibitive whereas heuristic or meta-heuristic approaches can yield acceptable results with less computation cost. In this paper, a customized evolutionary algorithm has been introduced and applied to power distribution network reconfiguration. The recombination operators of the algorithm are designed to preserve feasibility of solutions(radial structure of the network) thus considerably reducing the size of the search space. Consequently, improved repeatability of results as well as lower overall computational complexity of the optimization process have been achieved. The optimization process considers power losses and the system voltage profile, both aggregated into a scalar cost function. Power flow analysis is performed with the Open Distribution System Simulator,a simple and efficient simulation tool for electric distribution systems. Our approach is demonstrated using several networks of various sizes. Comprehensive benchmarking indicates superiority of the proposed technique over state-of-the-art methods from the literature.

关键词： Distribution network reconfiguration(DNR) Feasibility-preserving evolutionary optimization Power loss reduction Radial networks Voltage profile

Perturbed initial orbit determination

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Astrodynamics 2024年第3期8卷 401-416页

作者： alberto Fossà Matteo Losacco Roberto Armellin Institut Supérieur de l’Aéronautique et de l’Espace Toulouse31400France Te PūnahaĀtea-Space Institute The University of AucklandAuckland1010New Zealand

An algorithm for robust initial orbit determination (IOD) under perturbed orbital dynamics is presented. By leveraging map inversion techniques defined in the algebra of Taylor polynomials, this tool returns a highly accurate solution to the IOD problem and estimates a range centered on the aforementioned solution in which the true orbit should lie. To meet the specified accuracy requirements, automatic domain splitting is used to wrap the IOD routines and ensure that the local truncation error, introduced by a polynomial representation of the state estimate, remains below a predefined threshold. The algorithm is presented for three types of ground-based sensors, namely range radars, Doppler-only radars, and optical telescopes, by considering their different constraints in terms of available measurements and sensor noise. Finally, the improvement in performance with respect to a Keplerian-based IOD solution is demonstrated using large-scale numerical simulations over a subset of tracked objects in low Earth orbit.

关键词： initial orbit determination(IOD) range radar Doppler radar optical telescope differential algebra(DA)

Synthesis of palladium-rhodium bimetallic nanoparticles for formic acid dehydrogenation

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Journal of Energy Chemistry 2021年第1期30卷 301-309,I0010页

作者： Ilaria Barlocco Sofia Capelli Elisa Zanella Xiaowei Chen Juan JDelgado alberto Roldan Nikolaos Dimitratos alberto Villa Dipartimento di Chimica Universitàdegli Studi di MilanoMilan I-20133Italy Departamento de Ciencia de los Materiales Ingeniería Metalúrgica y Química InorgánicaFacultad de CienciasUniversidad de CádizCampus Río San PedroPuerto Real(Cádiz)E-11510Spain School of Chemistry Cardiff UniversityMain BuildingPark PlaceCF103AT CardiffUnited Kingdom Dipartimento di Chimica Industriale e dei Materiali Alma Mater Studiorum Universitàdi BolognaViale Risorgimento 4I-40136 BolognaItaly

Herein,we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios(nominal molar ratio:80-20,60-40,40-60,20-80) and the corresponding Pd and Rh monometallic ones by sol immobilization using polyvinyl alcohol(PVA) as protecting agent and NaBH4 as reducing agent,using carbon nanofibers with high graphitization degree(HHT) as the desired *** synthesized catalysts were characterized by means of Transmission Electron Microscopy(TEM) and inductively coupled plasma optical emission spectroscopy(ICP-OES).TEM shows that the average particle size of the Pd-Rh nanoparticles is the range of 3-4 nm,with the presence of few large agglomerated *** bimetallic catalysts,EDX-STEM analysis of individual nanoparticles demonstrated the presence of random-alloyed nanoparticles even in all cases Rh content is lower than the nominal one(calculated Pd:Rh molar ratio:90-10,69-31,49-51,40-60).The catalytic performance of the Pd-Rh catalysts was evaluated in the liquid phase dehydrogenation of formic acid to *** was found that Pd-Rh molar ratio strongly influences the catalytic ***-rich catalysts were more active than Rh-rich ones,with the highest activity observed for Pd90:Rh10(1792 h^(-1)),whereas Pd69:Rh31(921 h^(-1)) resulted the most stable during recycling ***,Pd90:Rh10 was chosen as a representative sample for the liquid-phase hydrogenation of muconic acid using formic acid as hydrogen donor,showing good yield to adipic acid.

关键词： Palladium Rhodium Alloy Formic acid Hydrogen Muconic acid

Therapeutic approaches for portal biliopathy: A systematic review

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World Journal of Gastroenterology 2016年第45期22卷 9909-9920页

作者： Irene Franceschet alberto Zanetto alberto Ferrarese Patrizia Burra Marco Senzolo Gastroenterology Unit Department of Surgery Oncology and Gastroenterology University Hospital of Padua Multivisceral Transplant Unit Department of Surgery Oncology and Gastroenterology University Hospital of Padua

Portal biliopathy(PB) is defined as the presence of biliary abnormalities in patients with non-cirrhotic/nonneoplastic extrahepatic portal vein obstruction(EHPVO) and portal cavernoma(PC). The pathogenesis of PB is due to ab extrinseco compression of bile ducts by PC and/or to ischemic damage secondary to an altered biliary vascularization in EHPVO and PC. Although asymptomatic biliary abnormalities can be frequently seen by magnetic resonance cholangiopancreatography in patients with PC(77%-100%), only a part of these(5%-38%) are symptomatic. Clinical presentation includes jaundice, cholangitis, cholecystitis, abdominal pain, and cholelithiasis. In this subset of patients is required a specific treatment. Different therapeutic approaches aimed to diminish portal hypertension and treat biliary strictures are available. In order to decompress PC, surgical porto-systemic shunt or transjugular intrahepatic porto-systemic shunt can be performed, and treatment on the biliary stenosis includes endoscopic(Endoscopic retrograde cholangiopancreatography with endoscopic sphincterotomy, balloon dilation, stone extraction, stent placement) and surgical(bilioenteric anastomosis, cholecystectomy) approaches. Definitive treatment of PB often requires multiple and combined interventions both on vascular and biliary system. Liver transplantation can be considered in patients with secondary biliary cirrhosis, recurrent cholangitis or unsuccessful control of portal hypertension.

关键词： Portal biliopathy Portal cavernoma Magnetic resonance cholangiopancreatography Endoscopic retrograde cholangiopancreatography Porto-systemic shunt

Helicobacter pylori infection in older people

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World Journal of Gastroenterology 2014年第21期20卷 6364-6373页

作者： alberto Pilotto Marilisa Franceschi Geriatrics Unit Azienda ULSS 16 PadovaSt. Antonio Hospital71-35127 PadovaItaly Endoscopic Unit Department of SurgeryULSS 4 AltoVicentino36014 - SantorsoItaly

Since the discovery of Helicobacter pylori(***)infection as the major cause of gastroduodenal disorders three decades ago,*** has been the focus of active research and debate in the scientific *** linkage to several diseases,such as peptic ulcer disease,gastritis and gastric malignancy is *** particular,it has been noticed that,as the aged population is increasing worldwide,older people are at increased risk of developing several gastroduodenal diseases and related *** the same time,gastric cancer is definitely more frequent in elderly than in adult and young *** addition,it has been showed that peptic ulcer and related complications occur much more commonly in aged individuals than in young people,resulting in a significantly higher *** this infection plays a crucial role in gastrointestinal disorders affecting all age groups and in particular older people,only a few studies have been published regarding the *** article presents an overview of the epidemiology,diagnosis,clinical manifestations and therapy of *** infection in elderly people.

关键词： Elderly Helicobacter pylori Diagnosis Clinical features Treatment

Looking for stability in proof-of-stake based consensus mechanisms

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Blockchain(Research and Applications) 2024年第4期5卷 41-50页

作者： alberto Leporati Lorenzo Rovida Department of Informatics Systems and CommunicationUniversity of Milano-BicoccaViale Sarca 336Milan 20126Italy

The Proof-of-Stake(PoS)consensus algorithm has been criticized in the literature and in several cryptocurrency communities,due to the so-called compounding effect:who is richer has more coins to stake,therefore a higher probability of being selected as a block validator and obtaining the corresponding rewards,thus becoming even *** this paper,we present a PoS simulator written in the Julia language that allows one to test several variants of PoS-based consensus algorithms,tweak their parameters,and observe how the distribution of cryptocurrency coins among users evolves over *** a tool can be used to investigate which combinations of parameter values allow to obtain a“fair”and stable consensus algorithm,in which,over the long term,no one gets richer or poorer by the mere act of validating *** on this investigation,we also introduce a new PoS-based consensus mechanism that allows the system to keep the wealth distribution stable even after a large number of epochs.

关键词： Blockchain Proof-of-stake Compounding effect Wealth distribution Tokenomics

An Optimization Model for Reliability Improvement and Cost Reduction Through EV Smart Charging

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 608-620页

作者： Jinping Zhao Ali Arefi alberto Borghetti Gerard Ledwich School of Engineering and Energy Murdoch UniversityPerthAustralia Department of Electrical Electronicand Information EngineeringUniversity of BolognaBologna40126Italy School of Electrical Engineering and Robotics Queensland University of TechnologyBrisbaneQLD 4000Australia

There is a general concern that the increasing penetration of electric vehicles(EVs)will result in higher aging failure probability of equipment and reduced network *** electricity costs may also increase,due to the exacerbation of peak load led by uncontrolled EV *** paper proposes a linear optimization model for the assessment of the benefits of EV smart charging on both network reliability improvement and electricity cost *** objective of the proposed model is the cost minimization,including the loss of load,repair costs due to aging failures,and EV charging *** proposed model incorporates a piecewise linear model representation for the failure probability distributions and utilizes a machine learning approach to represent the EV charging *** two different test systems(a 5-bus network and the IEEE 33-bus network),this paper compares aging failure probabilities,service unavailability,expected energy not supplied,and total costs in various scenarios with and without the implementation of EV smart charging.

关键词： Aging failure electric vehicle(EV) EV charging power system reliability expected energy not supplied distribution network.

Post-liver transplant hepatitis C virus recurrence: An unresolved thorny problem

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World Journal of Gastroenterology 2014年第32期20卷 11095-11115页

作者： alberto Grassi Giorgio Ballardini Internal Medicine and Hepatology Division Department of Internal Medicine "Infermi" Hospital Internal Medicine and Hepatology Division Department of Internal Medicine "Infermi" Hospita

Hepatitis C virus (HCV)-related cirrhosis represents the leading cause of liver transplantation in developed, Western and Eastern countries. Unfortunately, liver transplantation does not cure recipient HCV infection: reinfection universally occurs and disease progression is faster after liver transplant. In this review we focus on what happens throughout the peri-transplant phase and in the first 6-12 mo after transplantation: during this crucial period a completely new balance between HCV, liver graft, the recipient’s immune response and anti-rejection therapy is achieved that will deeply affect subsequent outcomes. Nearly all patients show an early graft reinfection, with HCV viremia reaching and exceeding pre-transplant levels; in this setting, histological assessment is essential to differentiate recurrent hepatitis C from acute or chronic rejection; however, differentiating the two patterns remains difficult. The host immune response (mainly cellular mediated) appears to be crucial both in the control of HCV infection and in the genesis of rejection, and it is also strongly influenced by immunosuppressive treatment. At present no clear immunosuppressive strategy could be strongly recommended in HCV-positive recipients to prevent HCV recurrence, even immunotherapy appears to be ineffective. Nonetheless it seems reasonable that episodes of rejection and over-immunosuppression are more likely to enhance the risk of HCV recurrence through immunological mechanisms. Both complete prevention of rejection and optimization of immunosuppression should represent the main goals towards reducing the rate of graft HCV reinfection. In conclusion, post-transplant HCV recurrence remains an unresolved, thorny problem because many factors remain obscure and need to be better determined.

关键词： Hepatitis C virus Liver transplantation Hepatitis C antigens Graft rejection Immunosuppression

The marine Jurassic of Argentina： a biostratigraphic framework

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Episodes 2008年第3期31卷 326-335页

作者： alberto C. Riccardi Facultad de Cieneias Naturales y Museo Universidad Nacional de La Plata Paseo del Bosque s/n 1900 La Plata Argentina

In Argentina the best and most complete marine Juras- sic succession is exposed between 32° and 39° S, along a N-S belt roughly coincident with the border with Chile. Here all stages, except the Kimmeridgian, are represented by marine facies. Ammonites have provided a biostratigraphic framework to date and correlate lithostratigraphic units and sequences, to reconstruct the history of the marine fill, and allow the development of other palaeontological and geological studies. Recent studies on the systematics and/or biostratigra- phy of Andean ammonites have provided the basis for the presentation of a summary of the 45 ammonite zones of the Jurassic of west-central Argentina and to stress its significance in reconstructing the palaeogeographic evolution of that region.

关键词：侏罗纪海洋阿根廷生物地层学