15,564 research outputs found
Event by Event Analysis of High Multiplicity Events Produced in 158 A GeV/c 208 Pb- 208 Pb Collisions
An extensive analysis of individual high multiplicity events produced in 158
A GeV /c 208Pb- 208Pb collisions is carried by adopting different methods to
examine the anomalous behavior of these rare events. A method of selecting the
events with densely populated narrow regions or spikes out of a given sample of
collision events is discussed.Employing this approach two events with large
spikes in their eta- and phi- distributions are selected for further analysis.
For the sake of comparison, another two events which do not exhibit such spikes
are simultaneously analyzed. The findings suggest that the systematic studies
of particle density fluctuations in one- and two-dimensional phase-spaces and
comparison with those obtained from the studies of correlation free Monte Carlo
events, would be useful for identifying the events with large dynamical
fluctuations. Formation of clusters or jet like phenomena in multihadronic
final states in individual events is also discussed and the experimental
findings are compared with the independent particle emission hypothesis by
carrying out Monte Carlo simulations
Modelling and control of a wheelchair on two wheels
Wheelchairs on two wheels are needed for disabled
persons to perform some of the essential tasks in their
living and work environments. In fact it offers great
advantages and efficiency for the user. Besides
allowing a disabled to lead independent life, it is
expected not to take much space during mobility as
compared to when it is on four wheels and thus a
wheelchair on two wheels has associated design and
development challenges. These include modelling and
controller design for the system to perform comparably
similar to normal four-wheeled wheelchair. In this
paper physical model of a wheelchair on two wheels
that mimics double inverted pendulum is designed and
a novel fuzzy logic control mechanism is developed
and tested with control of the two-wheeled wheelchair
Forward and backward motion control of wheelchair on two wheels
The challenge in designing wheelchair on two wheels involves the design and implementation of suitable control
strategies for a two wheeled wheelchair to perform comparably similar to a normal four wheeled wheelchair. It is important to note that a wheelchair on two wheels is expected not to take much space during mobility as compared to when it is on four wheels. Moreover, disabled people are encouraged and expected to perform most activities that others can do and hence lead an independent life. Thus, wheelchairs on two wheels are needed for disabled persons to perform some of the essential tasks in their living and work environments. In this research a model of the standard wheelchair is developed as a test and verification platform using Visual Nastran software. Novel fuzzy logic control strategies are designed for lifting up the chair transforming a four-wheeled wheelchair to a two-wheeled
wheelchair) and maintaining stability and balance while on two wheels. Furthermore, position control for forward
and backward mobility of the wheelchair on two wheels is
developed using fuzzy logic control. Simulation results of the proposed control strategy are presented and discussed
Error Estimation of Numerical Integration Methods
We compare the accuracy of numerical integral methods like Newton-Cotes method and Gaussian Quadrature Rule (GQR) for the model problem and tested for another problem to verify the results. From results we notice that error of GQR is about 10 times less than Newton-Cotes formulas. For this reason we prefer GQR over other methods. But GQR uses nodes and weights which is a tedious work. This di๏ฌculty can overcome by using the idea of ย โthree-term recurrenceโ relation. We can transform the problem of ๏ฌnding the nodes and weights for GQR to one of ๏ฌnding eigenvalues and eigenvectors of a symmetric tridiagonal matrix. Keywords: Numerical integration; Gaussian Quadrature rules; error estimate; convergence rate
Spectral Efficiency Maximization of a Single Cell Massive MU-MIMO Down-Link TDD System by Appropriate Resource Allocation
This paper deals with the problem of maximizing the spectral efficiency in a massive multi-user MIMO downlink system, where a base station is equipped with a very large number of antennas and serves single-antenna users simultaneously in the same frequency band, and the beamforming training scheme is employed in the time-division duplex mode. An optimal resource allocation that jointly selects the training duration on uplink transmission, the training signal power on downlink transmission, the training signal power on uplink transmission, and the data signal power on downlink transmission is proposed in such a way that the spectral efficiency is maximized given the total energy budget. Since the spectral efficiency is the main concern of this work, and its calculation using the lower bound on the achievable rate is computationally very intensive, in this paper, we also derive approximate expressions for the lower bound of achievable downlink rate for the maximum ratio transmission (MRT) and zero-forcing (ZF) precoders. The computational simplicity and accuracy of the approximate expressions for the lower bound of achievable downlink rate are validated through simulations. By employing these approximate expressions, experiments are conducted to obtain the spectral efficiency of the massive MIMO downlink time-division duplexing system with the optimal resource allocation and that of the beamforming training scheme. It is shown that the spectral efficiency of the former system using the optimal resource allocation is superior to that yielded by the latter scheme in the cases of both MRT and ZF precoders
A PLS-SEM Neural Network Approach for Understanding Cryptocurrency Adoption
ยฉ 2013 IEEE. The majority of previous research on new technology acceptance has been conducted with single-step Structural Equation Modeling (SEM) based methods. The primary purpose of the study is to enhance the new technology acceptance based research with the Artificial Neural Network (ANN) method to enable more precise and in-depth research results as compared to the single-step SEM method. This study measures the relation between technology readiness dimension (optimism, innovativeness, discomfort, insecurity) and the technology acceptance (perceived ease of use and perceived usefulness) - and the intention to use cryptocurrency, such as bitcoin. The contribution of this study include the use of a multi-analytical approach by combining Partial Least Squares- Structural Equation Modeling (PLS-SEM) and Artificial Neural Network (ANN) analysis. First, PLS-SEM was applied to assess which factor has significant influence toward intention to use cryptocurrency. Second, an ANN was employed to rank the relative influence of the significant predictor variables attained from the PLS-SEM. The findings of the two-step PLS-SEM and ANN approach confirm that the use of ANN further verifies the results obtained by the PLS-SEM analysis. Also, ANN is capable of modelling complex linear and non-linear relationships with high predictive accuracy compared to SEM methods. Also, an Importance-Performance Map Analysis (IPMA) of the PLS-SEM results provides a more specific understanding of each factor's importance-performance
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