Non-recursive equivalent of the conjugate gradient method without the need to restart

A simple alternative to the conjugate gradient(CG) method is presented; this method is developed as a special case of the more general iterated Ritz method (IRM) for solving a system of linear equations. This novel algorithm is not based on conjugacy, i.e. it is not necessary to maintain overall orthogonalities between various vectors from distant steps. This method is more stable than CG, and restarting techniques are not required. As in CG, only one matrix-vector multiplication is required per step with appropriate transformations. The algorithm is easily explained by energy considerations without appealing to the A-orthogonality in n-dimensional space. Finally, relaxation factor and preconditioning-like techniques can be adopted easily.Comment: 9 page

Dynamic analysis of the tramcar & track interaction

Prikazan je numerički model gibanja tramvajskog vozila. Tračnica je modelirana kao Euler-Bernullijev kontinuirani nosač s diskretno raspodijeljenom masom. Vozilo je diskretizirano s tri koncentrirane mase i prijenosom opterećenja preko jednog kotača. Ležajevi nosača i veze među masama modelirane su Kelvinovim reološkim elementima. Sustav diferencijalnih jednadžbi gibanja riješen je metodom prediktor-(re)korektor, a kontakt kotača i tračnice proračunan je primjenom metoda sila.The numerical model of tramcar motion is presented. The rail is modelled as an Euler-Bernoulli continuous beam with the discretely distributed mass. The vehicle is discretized with three concentrated masses, and with load transfer via one wheel. Beam bearings and mass links are modelled by means of Kelvin rheological elements. The differential equation system for motion was solved by the predictor - (re)corrector method, and the wheel and rail contact was calculated by means of the force methods

Dynamic analysis of the tramcar & track interaction

Prikazan je numerički model gibanja tramvajskog vozila. Tračnica je modelirana kao Euler-Bernullijev kontinuirani nosač s diskretno raspodijeljenom masom. Vozilo je diskretizirano s tri koncentrirane mase i prijenosom opterećenja preko jednog kotača. Ležajevi nosača i veze među masama modelirane su Kelvinovim reološkim elementima. Sustav diferencijalnih jednadžbi gibanja riješen je metodom prediktor-(re)korektor, a kontakt kotača i tračnice proračunan je primjenom metoda sila.The numerical model of tramcar motion is presented. The rail is modelled as an Euler-Bernoulli continuous beam with the discretely distributed mass. The vehicle is discretized with three concentrated masses, and with load transfer via one wheel. Beam bearings and mass links are modelled by means of Kelvin rheological elements. The differential equation system for motion was solved by the predictor - (re)corrector method, and the wheel and rail contact was calculated by means of the force methods

EuReCa ONE—27 Nations, ONE Europe, ONE Registry A prospective one month analysis of out-of-hospital cardiac arrest outcomes in 27 countries in Europe

AbstractIntroductionThe aim of the EuReCa ONE study was to determine the incidence, process, and outcome for out of hospital cardiac arrest (OHCA) throughout Europe.MethodsThis was an international, prospective, multi-centre one-month study. Patients who suffered an OHCA during October 2014 who were attended and/or treated by an Emergency Medical Service (EMS) were eligible for inclusion in the study. Data were extracted from national, regional or local registries.ResultsData on 10,682 confirmed OHCAs from 248 regions in 27 countries, covering an estimated population of 174 million. In 7146 (66%) cases, CPR was started by a bystander or by the EMS. The incidence of CPR attempts ranged from 19.0 to 104.0 per 100,000 population per year. 1735 had ROSC on arrival at hospital (25.2%), Overall, 662/6414 (10.3%) in all cases with CPR attempted survived for at least 30 days or to hospital discharge.ConclusionThe results of EuReCa ONE highlight that OHCA is still a major public health problem accounting for a substantial number of deaths in Europe.EuReCa ONE very clearly demonstrates marked differences in the processes for data collection and reported outcomes following OHCA all over Europe. Using these data and analyses, different countries, regions, systems, and concepts can benchmark themselves and may learn from each other to further improve survival following one of our major health care events

Nonrecursive Equivalent of the Conjugate Gradient Method without the Need to Restart

A simple alternative to the conjugate gradient (CG) method is presented; this method is developed as a special case of the more general iterated Ritz method (IRM) for solving a system of linear equations. This novel algorithm is not based on conjugacy; i.e., it is not necessary to maintain overall orthogonalities between various vectors from distant steps. This method is more stable than CG, and restarting techniques are not required. As in CG, only one matrix-vector multiplication is required per step with appropriate transformations. The algorithm is easily explained by energy considerations without appealing to the A-orthogonality in n-dimensional space. Finally, relaxation factor and preconditioning-like techniques can be adopted easily

Influence of Multiple-Support Excitation on Seismic Response of Reinforced Concrete Arch Bridges

Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the influence of multiple-support excitation accounting for coherency loss and wave-passage effects on the seismic response of reinforced concrete deck arch bridges of long spans founded on rock sites. Parametric numerical study was conducted using the time-history method, the response spectrum method, and a simplified procedure according to the European seismic standards. Results showed that multiple-support excitation had a detrimental influence on response of almost all analyzed bridges regardless of considered arch span. Both considered spatial variation effects, acting separately or simultaneously, proved to be very important, with their relative significance depending on the response values and arch locations analyzed and seismic records used. Therefore, it is suggested that all spatially variable ground-motion effects are taken into account in seismic analysis of similar bridges