Adaptive digital self-interference cancellation based on fractional order LMS in LFMCW radar

Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.

ORDER OF MEAN APPROXIMATION BY MIXED QUASI HERMITE-FEJER INTERPOLATION

In this paper we introduce a new kind of the mixed Hermite--Fejér interpolation with boundary condi- tions and obtain the mean approximation order.Our results include a new theorem of Varma and Prasad.Be- sides,we also get some other results about the mean approximation.

Target reliability index for serviceability limit state of single piles

The objective is to develop an approach for the determination of the target reliability index for serviceability limit state(SLS) of single piles. This contributes to conducting the SLS reliability-based design(RBD) of piles. Based on a two-parameter,hyperbolic curve-fitting equation describing the load-settlement relation of piles, the SLS model factor is defined. Then, taking into account the uncertainties of load-settlement model, load and bearing capacity of piles, the formula for computing the SLS reliability index(βsls) is obtained using the mean value first order second moment(MVFOSM) method. Meanwhile, the limit state function for conducting the SLS reliability analysis by the Monte Carlo simulation(MCS) method is established. These two methods are finally applied to determine the SLS target reliability index. Herein, the limiting tolerable settlement(slt) is treated as a random variable. For illustration, four load test databases from South Africa are compiled again to conduct reliability analysis and present the recommended target reliability indices. The results indicate that the MVFOSM method overestimates βsls compared to that computed by the MCS method. Besides, both factor of safety(FS) and slt are key factors influencing βsls, so the combination of FS and βsls is welcome to be used for the SLS reliability analysis of piles when slt is determined. For smaller slt, pile types and soils conditions have significant influence on the SLS target reliability indices; for larger slt, slt is the major factor having influence on the SLS target reliability indices. This proves that slt is the most key parameter for the determination of the SLS target reliability index.

A NUMERICAL METHOD FOR SECOND ORDER MEAN FORCES AND SLOWLY VARYING FORCES ON A FLOATING STRUCTURE

Existing far field expressions of second order potentials are by no means complete.Hence there has been no exact far field expression of second order potentials.In this paper the far field expression for Φ_d^((2)) is purposely avoided in deducing the formulae of second order forces and a series of functions Φ_(dRn)^((?)) are used.The far field expression of is given,which for (x,U,z)∈Σ,φ_(dRn)^((2))(?) φ_d^((2)).Using these properties formulae for calculating second order diffraction forces are obtained.To calculate the integral ∫∫_(?)1/g f_(?)Ψ_(?)ds it is divided into two parts.One is the integral over a finite domain and the function under the integral is continuous,so the usual approximate integration formulae may be used. The other is the integral over an infinite domain.Using the far field expression of first order potentials,formulae for calculating the integral to meet given accuracies are given. The mooring force in surge direction is used for comparison between numerical predictions and experimental measurements.The predicted results are checked against the measured value in a specially designed test.In the low frequency domain of interest,the mooring forces in surge,for calculated and experimental spectra are in good consistency so long as the damping coefficients is choosen appropriately.

[ℓ_(p)]_(e.r) Euler-Riesz Difference Sequence Spaces

Bas¸ar and Braha[1],introduced the sequence spaces˘ℓ_(∞),c˘and c˘0 of EulerCesaro bounded,convergent and null difference sequences and studied their some´properties.Then,in[2],we introduced the sequence spaces[ℓ_(∞)]_(e.r),[c]_(e.r)and[c_(0)]_(e.r)of Euler-Riesz bounded,convergent and null difference sequences by using the composition of the Euler mean E1 and Riesz mean Rq with backward difference operator∆.The main purpose of this study is to introduce the sequence space[ℓ_(p)]_(e.r)of Euler-Riesz p−absolutely convergent series,where 1≤p<∞,difference sequences by using the composition of the Euler mean E1 and Riesz mean Rq with backward difference operator∆.Furthermore,the inclusionℓ_(p)⊂[ℓ_(p)]_(e.r)hold,the basis of the sequence space[ℓ_(p)]_(e.r)is constucted andα−,β−andγ−duals of the space are determined.Finally,the classes of matrix transformations from the[ℓ_(p)]_(e.r)Euler-Riesz difference sequence space to the spacesℓ_(∞),c and c0 are characterized.We devote the final section of the paper to examine some geometric properties of the space[ℓ_(p)]_(e.r).