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Search Results: 1 - 10 of 167594 matches for " E. Matsinos "
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Analysis of the Low-Energy π±p Elastic-Scattering Data  [PDF]
E. Matsinos, G. Rasche
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.310174
Abstract: We report the results of a phase-shift analysis (PSA) of the low-energy π±p elastic-scattering data. Following the method which we had set forth in our previous PSA [1], we first investigate the self-consistency of the low-energy π±p elastic-scattering databases, via two separate analyses of (first) the π+p and (subsequently) the π-p elastic-scattering data. There are two main differences to our previous PSA: 1) we now perform only one test for the acceptance of each data set (based on its contribution to the overall 2) and 2) we adopt a more stringent acceptance criterion in the statistical tests. We show that it is possible to obtain self-consistent databases after removing a very small amount of the data (4.57% of the initial database). We subsequently fit the ETH model [38] to the truncatedπ±p elastic-scattering databases. The model-parameter values show reasonable stability when subjected to different criteria for the rejection of single data points and entire data sets. Our result for the pseudovector πNN coupling constant is 0.0726±0.0014. We extract the scattering lengths and volumes, as well as the s- and p-wave hadronic phase shifts up to T = 100 MeV. Large differences in the s-wave part of the interaction can be seen when comparing our hadronic phase shifts with the current SAID solution (WI08); there is general agreement in the p waves, save for the ~1/21- hadronic phase shift.
The low-energy constants of the pion-nucleon system
E. Matsinos
Physics , 1998,
Abstract: Recent analyses of low-energy pion-nucleon experimental data have provided clear evidence for the violation of the isospin symmetry of the strong interaction. In the present work, it is shown that the single-charge-exchange reaction is the culprit for the effect. Given the present experimental uncertainties, no evidence for isospin breaking was found in the two elastic-scattering processes for pion laboratory kinetic energies between 20 and 100 MeV. In agreement with most of the recent determinations, the value for the charged-pion coupling constant, extracted herein, is `small'. The energy dependence of the s- and p-wave hadronic phase shifts, obtained from low-energy elastic-scattering data exclusively, as well as their values in tabular form (including meaningful uncertainties), are provided. Discrepancies with two `standard' phase-shift solutions in the s-wave part of the interaction are seen; small differences may be observed in three of the p-wave channels.
A method for the determination of nuclear cross sections of proton beams by the collective model and extended nuclear-shell theory
W. Ulmer,E. Matsinos
Physics , 2010,
Abstract: A recapitulatory analysis of total nuclear cross sections of various nuclei is presented, which yields detailed knowledge on the different physical processes such as potential/resonance scatter and nuclear reactions. The physical base for potential/resonance scatter and the threshold energy resulting from Coulomb repulsion of nuclei are collective/oscillator models. The part pertaining to the nuclear reactions can only be determined by the microscopic theory (Schr\"odinger equation and strong interactions). The physical impact is the fluence decrease of proton beams in different media and the scatter behavior of secondary particles.
On using the Microsoft Kinect$^{\rm TM}$ sensors to determine the lengths of the arm and leg bones of a human subject in motion
M. J. Malinowski,E. Matsinos
Physics , 2015,
Abstract: The present study is part of a broader programme, exploring the possibility of involving the Microsoft Kinect$^{\rm TM}$ sensor in the analysis of human motion. We examine the output obtained from the two available versions of this sensor in relation to the variability of the estimates of the lengths of eight bones belonging to the subject's extremities: of the humerus (upper arm), ulna (lower arm, forearm), femur (upper leg), and tibia (lower leg, shank). Large systematic effects in the output of the two sensors have been observed.
Comparative study of the two versions of the Microsoft Kinect$^{\rm TM}$ sensor in regard to the analysis of human motion
M. J. Malinowski,E. Matsinos
Computer Science , 2015,
Abstract: The present paper is part of a broader programme, exploring the possibility of involving the Microsoft Kinect$^{\rm TM}$ sensor in the analysis of human motion. In this study, the output obtained from the two available versions of this sensor is critically examined. We demonstrate that the two outputs differ in regard to the variation of the physical quantities involved in the modelling of the human motion. As the original sensor has been found unsuitable for applications requiring high precision, the observed differences in the output of the two sensors call for the validation of the upgraded sensor on the basis of a marker-based system.
On using the Microsoft Kinect$^{\rm TM}$ sensors in the analysis of human motion
M. J. Malinowski,E. Matsinos,S. Roth
Physics , 2014,
Abstract: The present paper aims at providing the theoretical background required for investigating the use of the Microsoft Kinect$^{\rm TM}$ (`Kinect', for short) sensors (original and upgraded) in the analysis of human motion. Our methodology is developed in such a way that its application be easily adaptable to comparative studies of other systems used in capturing human-motion data. Our future plans include the application of this methodology to two situations: first, in a comparative study of the performance of the two Kinect sensors; second, in pursuing their validation on the basis of comparisons with a marker-based system (MBS). One important feature in our approach is the transformation of the MBS output into Kinect-output format, thus enabling the analysis of the measurements, obtained from different systems, with the same software application, i.e., the one we use in the analysis of Kinect-captured data; one example of such a transformation, for one popular marker-placement scheme (`Plug-in Gait'), is detailed. We propose that the similarity of the output, obtained from the different systems, be assessed on the basis of the comparison of a number of waveforms, representing the variation within the gait cycle of quantities which are commonly used in the modelling of the human motion. The data acquisition may involve commercially-available treadmills and a number of velocity settings: for instance, walking-motion data may be acquired at $5$ km/h, running-motion data at $8$ and $11$ km/h. We recommend that particular attention be called to systematic effects associated with the subject's knee and lower leg, as well as to the ability of the Kinect sensors in reliably capturing the details in the asymmetry of the motion for the left and right parts of the human body. The previous versions of the study have been withdrawn due to the use of a non-representative database.
Collimator effects in proton planning
Evangelos Matsinos
Physics , 2008,
Abstract: The present paper pertains to corrections which are due to the presence of beam-limiting and beam-shaping devices in proton planning. Two types of corrections are considered: those which are due to the nonzero thickness of such devices (geometrical effects) and those relating to the scattering of beam particles off their material. The application of these two types of corrections is greatly facilitated by decomposing the physical effects (i.e., the contribution to the fluence) of two-dimensional objects (i.e., of the apertures of the devices) into one-dimensional, easily-calculable contributions. To minimise the time requirements in the derivation of the scattering corrections, a two-step process is introduced. The first step occurs at beam-configuration phase and comprises the analysis of half-block fluence measurements and the extraction of the one parameter of the model which is used in the description of the beamline characteristics; subsequently, a number of Monte-Carlo runs lead to the determination of the parameters of a convenient parameterisation of the relevant fluence contributions. The second step involves (at planning time) the reconstruction of the parameters (which are used in the description of the scattering contributions) via simple interpolations, performed on the results obtained during the beam-configuration phase. It is shown that the inclusion of the scattering effects leads to substantial improvement in the reproduction of the experimental data. The contributions from the block-thickness and block-scattering effects have been presented separately in the case of a simple water phantom. In this example, the maximal contribution of the block-relating effects amounts to a few percent of the prescribed dose.
Steady-state cracking in brittle substrates beneath adherent films: revisited
Evangelos Matsinos
Physics , 2011,
Abstract: This is a technical note aiming at the re-examination of the phenomenon of the steady-state cracking in the two-layer system. The method of Suo and Hutchinson, as introduced in their 1989 paper, is followed. Our solution is compared with the one appearing in that paper for the substrate-to-film thickness ratio $\lambda_0=10$. We obtain results at three $\lambda_0<10$ values. Combined with the results for $\lambda_0=10$, the new sets of values cover thickness ratios between 1 and 10, sufficient for determining crack initiation and propagation in almost every relevant problem. We present our results in tables (and figures), thus facilitating their implementation and use.
Modelling of the motion of a Mecanum-wheeled vehicle
Evangelos Matsinos
Physics , 2012,
Abstract: The present document aims at developing the formalism needed in order to describe the two-dimensional motion of a vehicle with Mecanum wheels, including the effects of resistive friction. The description of recently-acquired experimental data, on the basis of this model, is found satisfactory.
Processing of acoustical signals via a wavelet-based analysis
Evangelos Matsinos
Computer Science , 2015,
Abstract: In the present paper, details are given on the implementation of a wavelet-based analysis tailored to the processing of acoustical signals. The family of the suitable wavelets (`Reimann wavelets') are obtained in the time domain from a Fourier transform, extracted in Ref.~\cite{r1} after invoking theoretical principles and time-frequency localisation constraints. A scheme is set forth to determine the optimal values of the parameters of this type of wavelet on the basis of the goodness of the reproduction of a $30$-s audio file containing harmonic signals corresponding to six successive $A$ notes of the chromatic musical scale, from $A_2$ to $A_7$. The quality of the reproduction over about six and a half octaves is investigated. Finally, details are given on the incorporation of the re-assignment method in the analysis framework, as the means a) to determine the important contributions of the wavelet transforms and b) to suppress noise present in the signal.
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