Nonlinear system modeling based on constrained Volterra series estimates

A simple nonlinear system modeling algorithm designed to work with limited \emph{a priori }knowledge and short data records, is examined. It creates an empirical Volterra series-based model of a system using an $l_{q}$-constrained least squares algorithm with $q\geq 1$. If the system $m\left( \cdot \right)$ is a continuous and bounded map with a finite memory no longer than some known $\tau$, then (for a $D$ parameter model and for a number of measurements $N$) the difference between the resulting model of the system and the best possible theoretical one is guaranteed to be of order $\sqrt{N^{-1}\ln D}$, even for $D\geq N$. The performance of models obtained for $q=1,1.5$ and $2$ is tested on the Wiener-Hammerstein benchmark system. The results suggest that the models obtained for $q>1$ are better suited to characterize the nature of the system, while the sparse solutions obtained for $q=1$ yield smaller error values in terms of input-output behavior

Commutation unit of satellite motor with rotating body

W artykule opisano problematykę konstrukcji rozrządu w silniku z satelitowym mechanizmem roboczym, w którym obraca się obwodnica, a planeta jest nieruchoma. Wykazano, że w płytach rozrządu liczba otworów dopływu i odpływu jest równa liczbie garbów planety. Przedstawiono również dopuszczalne kształty tych otworów i ich rozmieszczenie w płycie rozrządu. Ponadto wykazano, że jest możliwe zbudowanie działającego silnika satelitowego z obracającą się obwodnicą, a tym samym z obracającym się korpusem. W artykule opisano metodę eksperymentalnej weryfikacji poprawności działania rozrządu w takim silniku. Wyniki badań momentu i chłonności silnika przy stałym ciśnieniu zasilającym i małej stałej prędkości obrotowej korpusu (n = 1 obr./min) potwierdziły poprawność działania rozrządu.The article describes the problems of construction of the commutation unit in motor with satellite working mechanism where the curvature rotates and the planet is stationary. It has been shown that in the commutation plates the number of inflow and outflow holes is equal to the number of humps of the planet. Furthermore, it has been shown that it is possible to build the motor with the rotating curvature and thereby with the rotating body. The method of experimental verification of correct operation of commutation unit in the motor is also described. Test results of motor torque and capacity at constant supply pressure and low constalt speed (n = 1 rpm) have confirmed the correctness of commutation unit operation

Autofocusing with the help of orthogonal series transforms

An autofocus algorithm employing orthogonal series expansions is proposed. Several instances of the generic algorithm, based on discrete trigonometric, polynomial and wavelet series, are reviewed. The algorithms are easy to implement in the transform coders used in digital cameras. Formal analysis of the algorithm properties is illustrated in experiments. Some practical issues are also discussed

Comparison of the lubricant property of water, oil-in-water emulsion type HFA-E and oil Total Azolla 46 as working liquids in hydraulic systems

W artykule scharakteryzowano i opisano wyniki badań własności smarnych wody destylowanej, 1% emulsji oleju w wodzie typu HFA-E sporządzonej na bazie koncentratu do tworzenia emulsji Isosynth VH110BF, oleju Total Azolla 46 oraz, w celach porównawczych, samego koncentratu Isosynth VH110BF. Przedstawiono również wyniki badań powierzchniowego zużycia zmęczeniowego (pittingu) dla wyżej wymienionych czynników smarnych. Emulsja oleju w wodzie, olej oraz woda są czynnikami roboczym stosowanymi w układach hydraulicznych.The article characterises and describes the results of research (carried out on four-ball machine) of the lubricant property of distilled water, oil-in-water emulsion type HFA-E (1% oil in water) prepared on base of concentrate Isosynth VX110BF, oil Total Azolla 46 and the pure concentrate Isosynth VX110BF (only in comparison with oil, emulsion and water). In the article, results are shown of research (carried out on four-ball machine) rolling contact fatigue tests for water, emulsion, and oil as a means of lubricant. Oil-in-water emulsion HFA-E, oil and water are the working medium applied in hydraulic systems

On-line wavelet estimation of Hammerstein system nonlinearity

A new algorithm for nonparametric wavelet estimation of Hammerstein system nonlinearity is proposed. The algorithm works in the on-line regime (viz., past measurements are not available) and offers a convenient uniform routine for nonlinearity estimation at an arbitrary point and at any moment of the identification process. The pointwise convergence of the estimate to locally bounded nonlinearities and the rate of this convergence are both established

A simple scheme for semi-recursive identification of Hammerstein system nonlinearity by Haar wavelets

A simple semi-recursive routine for nonlinearity recovery in Hammerstein systems is proposed. The identification scheme is based on the Haar wavelet kernel and possesses a simple and compact form. The convergence of the algorithm is established and the asymptotic rate of convergence (independent of the input density smoothness) is shown for piecewise-Lipschitz nonlinearities. The numerical stability of the algorithm is verified. Simulation experiments for a small and moderate number of input-output data are presented and discussed to illustrate the applicability of the routine

Modeling and strength analysis of a vessel for transporting explosive materials

W pracy przedstawiono obliczenia oraz model rzeczywisty zbiornika do transportu przedmiotów zawierających materiały wybuchowe. Zbiornik wykonano w dwóch wersjach wyposażenia. Na wstępie wyznaczono graniczną wartość ciśnienia na czole fali uderzeniowej, pochodzącą od detonacji we wnętrzu zbiornika ładunku o masie 1 kg TNT. Następnie wykonano analityczne obliczenia wytężenia korpusu pojemnika. W celu weryfikacji poziomu naprężeń, na powierzchniach elementów konstrukcyjnych naklejono czujniki tensometryczne. W kolejnej fazie przeprowadzono badania doświadczalne na poligonie, poprzez zdetonowanie we wnętrzu zbiornika 1 kg TNT. Podczas badań wykonywano pomiary odkształceń. Analizę danych zmierzonych przedstawiono na wykresach w postaci rozkładu naprężeń w funkcji czasu.The paper presents calculations and a real model for a vessel transporting goods with explosive materials. Two options of the vessel were fabricated. An extreme value of pressure at the blast wave-front generated by the explosion of 1 kg TNT inside the vessel was determined at the beginning. Then analytical calculations of stress values for vessel frame were conducted. In order to verify the stress level, strain gauges have been attached to the surface of structural members. In the next stage experimental tests were conducted on the proving ground by explosion of 1 kg of TNT inside the vessel. Deformations were measured at the tests. An analysis of measured data is illustrated in diagrams of stress distribution versus time

Performance Evaluation of Signaling in the IP QoS System

The IP QoS System is based on next generation networks (NGN) and differentiated services (DiffServ) architectures. Its main part is a signaling system, which allows to send a request from a user to the system for establishing new connection with predefined quality of service assurance. In this paper we present trial results of the proposed signalling system. The experiments were performed to measure setup delay utilizing artificial call generator/analyzer. To obtain results we assumed different distributions of interarrival and call holding times based on the literature. The results show that the setup delay strongly depends on access time to network devices, however also on the assumed call holding time models

Deep Level Transient Spectroscopic Studies of MOCVD GaN Layers Grown on Sapphire

The deep level transient spectroscopy of GaN heteroepitaxial layers grown on sapphire was studied. The samples were Mg doped during the growth. The as-grown material is n-type. It becomes p-type after annealing. The samples were measured in the temperature range from 77 K to 420 K. In n-type GaN, one peak (EG1) with activation energy 0.75 eV was detected. In p-type, at least three peaks were observed: AS1 at temperature about 300 K and AS2, AS3 at about 400 K. The dominating one is AS3. It has an activation energy about 1.1 eV