A 1-bit Synchronization Algorithm for a Reduced Complexity Energy Detection UWB Receiver

This work investigates the possibility of performing synchronization in a reduced complexity Energy Detection receiver. A new receiver scheme employing a single comparator only is defined and the related synchronization algorithm is presented. The possibility of synchronizing has been analyzed both for an idealized Dirac Delta input signal and for realistic UWB signals obtained through the TG4a channel model. The matlab simulations show that it is possible to obtain coarse synchronization using a simple maximum detection algorithm computed on collected energies for the ideal case of Dirac Delta pulses. For realistic UWB signals better synchronization performances are possible by employing a searchback algorithm. Due to the low complexity of the receiver scheme, the synchronization algorithm requires a long locking time

Influence of post-cyclic loading on hemic peat

Construction on peat soils has proven to be a challenging task to civil engineers since this soil type has a significant issue that arises from common problems construction of roads, housing and embankment construction with regard to peat are stability, settlements and major problems were encountered especially on deep peat. For many years, in road design as an example, static loading method was applied in road designed by considering soil shear strength through static load and do not take into account the vehicular dynamic loading and shear strength thereafter. This fact is related to the shear strength of peat soil after dynamically loaded. The aim of this research is to establish the post-cyclic behaviour of peat soil after cyclically loaded and to assess the effect of parameters changes on static and post-cyclic behaviour of peat soil. 200 specimens are tested, and prepared under consolidated undrained triaxial with effective stresses at 25kPa, 50 kPa, and 100 kPa with different location from Parit Nipah, Johor, Parit Sulong, Batu Pahat, Johor and Beaufort, Sabah. These specimens tested using GDS Enterprise Level Dynamic Triaxial Testing System (ELDYN) apparatus. Whereas, dynamic load tests are carried out in different frequencies to simulate the loading type such as vibration of machineries, wind, traffic load and earthquake in field from 1.0 Hz, 2.0 Hz and 3.0 Hz with 100 numbers of loading cycles. Post-cyclic monotonic shear strength results and then compared to the static monotonic results. Significantly, showed some vital changes that leads to the changes of stress-strain behaviour. Apparently, the result shows that post-cyclic shear strength decreases with the increase of frequencies. Prior to critical yield strain level, the peat specimen experience a significant deformation. The deformation of peats triggers changes in soil structures that causes reduction in stress-strain behaviour. Thus, it can be concluded that the stress-strain behaviour of peat soil decreased after 100 numbers of cyclic loading in post-cyclic test as compared to the static tests, and it decreased substantially when frequencies were applied. The post-cyclic specimen had a lower undrained parameters than did the static. Reduction of cohesion value in postcylic compared to static almost 70% and reduction of friction angle is about 46.34%

Non-parametric linear time-invariant system identification by discrete wavelet transforms

We describe the use of the discrete wavelet transform (DWT) for non-parametric linear time-invariant system identification. Identification is achieved by using a test excitation to the system under test (SUT) that also acts as the analyzing function for the DWT of the SUT's output, so as to recover the impulse response. The method uses as excitation any signal that gives an orthogonal inner product in the DWT at some step size (that cannot be 1). We favor wavelet scaling coefficients as excitations, with a step size of 2. However, the system impulse or frequency response can then only be estimated at half the available number of points of the sampled output sequence, introducing a multirate problem that means we have to 'oversample' the SUT output. The method has several advantages over existing techniques, e.g., it uses a simple, easy to generate excitation, and avoids the singularity problems and the (unbounded) accumulation of round-off errors that can occur with standard techniques. In extensive simulations, identification of a variety of finite and infinite impulse response systems is shown to be considerably better than with conventional system identification methods.Department of Computin

A partial Fourier transform method for a class of hypoelliptic Kolmogorov equations

We consider hypoelliptic Kolmogorov equations in $n+1$ spatial dimensions, with $n\geq 1$, where the differential operator in the first $n$ spatial variables featuring in the equation is second-order elliptic, and with respect to the $(n+1)$st spatial variable the equation contains a pure transport term only and is therefore first-order hyperbolic. If the two differential operators, in the first $n$ and in the $(n+1)$st co-ordinate directions, do not commute, we benefit from hypoelliptic regularization in time, and the solution for $t>0$ is smooth even for a Dirac initial datum prescribed at $t=0$. We study specifically the case where the coefficients depend only on the first $n$ variables. In that case, a Fourier transform in the last variable and standard central finite difference approximation in the other variables can be applied for the numerical solution. We prove second-order convergence in the spatial mesh size for the model hypoelliptic equation $\frac{\partial u}{\partial t} + x \frac{\partial u}{\partial y} = \frac{\partial^2 u}{\partial x^2}$ subject to the initial condition $u(x,y,0) = \delta (x) \delta (y)$, with $(x,y) \in \mathbb{R} \times\mathbb{R}$ and $t>0$, proposed by Kolmogorov, and for an extension with $n=2$. We also demonstrate exponential convergence of an approximation of the inverse Fourier transform based on the trapezium rule. Lastly, we apply the method to a PDE arising in mathematical finance, which models the distribution of the hedging error under a mis-specified derivative pricing model