Search

Abstract: In this paper, a novel linear precoding scheme is proposed for downlink multiuser multiple-input multiple-output (MIMO) systems. The new algorithm uses the penalty function method to mitigate the co-channel interference and is formulated as a convex problem with general linear constraints. The constraints can be sum power, per-antenna power or per-antenna-group power constraints, hence the new algorithm is general and can be used in both single-cell and fully cooperative multi-cell scenarios. Moreover, the famous block diagonalization (BD) precoding can be considered as a special case of our method when a very large penalty factor is used. We study the optimal solution of this convex problem and propose an iterative algorithm to obtain the optimum based on the Lagrange dual method. Simulation results show that the proposed method significantly outperforms the BD method at low and moderate SNR values in terms of the weighted sum rate. [Copyright &y& Elsevier]

Abstract: Blind noise variance and SNR estimators based on information theoretic criteria for orthogonal frequency division multiplexing (OFDM) systems are proposed in this paper. By using the redundancy induced by the cyclic-prefix, the unknown channel order is estimated via minimum length description (MDL) or Akaike information criterion (AIC), and the noise variance and SNR can be obtained subsequently. The proposed methods do not require any pilot symbols and therefore improve the spectrum efficiency. Simulation results are presented to highlight the benefit of the proposed algorithms compared with the other existing blind methods. [Copyright &y& Elsevier]

Abstract: This paper addresses the problem of blind source separation (BSS) and presents an optimum step size which makes the nonlinear principal component analysis (NPCA) cost function descend in the fastest way. By applying this step size in the self-stabilized NPCA algorithm, a fast NPCA algorithm is obtained. Computer simulations of online BSS show that the new algorithm works more efficiently than the existing least-mean-square (LMS)-type and recursive least-squares (RLS)-type NPCA algorithms. [Copyright &y& Elsevier]

The measurement accuracy of Brillouin scattering spectra is crucial for ocean remote sensing by Brillouin scattering lidar. Due to the limited resolution of ICCD cameras, the traditional processing methods remain at the pixel or partial sub-pixel level, which cannot meet the requirements of high-performance lidar. In this paper, to extract the frequency shift with high precision from stimulated Brillouin scattering (SBS) lidar, a novel spectral processing method with sub-pixel recognition accuracy is proposed based on the Hessian matrix and Steger algorithm combined with the least square fitting method. Firstly, the Hessian matrix and Frangi filter are used for signal denoising. Then, the center points of SBS spectra at the sub-pixel level are extracted using the Steger algorithm and are connected and classified according to the signal type. On that basis, the frequency shifts of Brillouin scattering are calculated by using the center and radii of interference spectra after through fitting by the least squares method. Finally, the water temperatures are inverted by using the frequency shifts of Brillouin scattering. The results show that the processing method proposed in this paper can accurately calculate the frequency shift of Brillouin scattering. The measured errors of frequency shift are generally at an order of MHz, and the inversion accuracy of water temperature can be as low as 0.14 °C. This work is essential to the application for remote sensing the seawater parameters by using the Brillouin lidar technique. [ABSTRACT FROM AUTHOR]

Rock-like materials and Barton's standard joint curve were used to make filled joint specimens, and the shear characteristics of the filled joints were studied. Discrete element software was used to analyze the failure mechanism during filled joint shearing. Based on the experimental findings, a new theoretical model of joint shear strength was proposed. It was found that joint roughness has a great effect on filled joint shear failure, which is manifested via three different morphologies. The effects of the filler on the shear stress–strain curve are mainly a higher slope in the elastic phase and a lower slope in the plastic phase. The shear failure of the filled joint starts from local small damage of the filling and then progresses to failure of the bonding surface or the filling itself. Based on the proportion of the joint failure surface area to the joint surface area, a new formula for calculating shear strength is proposed. [ABSTRACT FROM AUTHOR]

Anti-CD38 monoclonal antibodies (mAbs), daratumumab, and isatuximab have represented a breakthrough in the treatment of multiple myeloma (MM). Recently, CD38-based mAbs were expected to achieve increasing potential beyond MM, which encouraged us to develop new anti-CD38 mAbs to meet clinical needs. In this study, we developed a novel humanized anti-CD38 antibody, FTL004, which exhibited enhanced pro-apoptotic ability and negligible binding to red blood cells (RBCs). FTL004 presented a better ability to induce direct apoptosis independent of Fc-mediated cross-linking against lymphoma and MM cell lines as well as primary myeloma cells derived from MM patients. For instance, FTL004 induced RPMI 8226 cells with 55% early apoptosis cells compared with 20% in the isatuximab-treated group. Of interest, FTL004 showed ignorable binding to CD38 on human RBCs in contrast to tumor cells, even at concentrations up to 30 μg/mL. Furthermore, with an engineered Fc domain, FTL004 displayed stronger antibody-dependent cellular cytotoxicity (ADCC) against CD38+ malignant cells. In vivo MM and non-Hodgkin lymphoma tumor xenograft models showed that FTL004 possessed an effective anti-tumor effect. Cryo-electron microscopy structure resolved two epitope centers of FTL004 on CD38: one of which was unique while the other partly overlapped with that of isatuximab. Taken together, FTL004 distinguishes it from other CD38 targeting mAbs and represents a potential candidate for the treatment of MM and non-Hodgkin lymphoma. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we propose a novel blind adaptive multiuser detector based on the affine projection algorithm (APA) for asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems over a multipath fading channel. Computational complexities of least mean-squares (LMS), Kalman filter and APA-based blind adaptive multiuser detector are compared. The proposed detector is shown to outperform the LMS detector and has similar convergence and detection properties as the Kalman filtering with much reduced computation cost. [Copyright &y& Elsevier]

Abstract: This paper addresses the problem of blind source separation and presents a fixed-point nonlinear principal component analysis (NPCA) algorithm. It is a block-wise batch algorithm and gives an alternative perspective on existing adaptive online NPCA algorithms. Utilizing new activation functions that automatically satisfy a stability condition, the proposed algorithm can separate mixed signals with sub- and super-Gaussian source distributions. The efficiency is confirmed by extensive computer simulations on man-made sources as well as practical speech signals. [Copyright &y& Elsevier]

Abstract: This paper proposes a method for calculating a nonnegative time–frequency distribution (TFD) whose concentration is identical to that of Wigner–Ville distribution (WVD) when instantaneous frequencies (IFs) of the best-matched elementary functions of the signal under analysis are pre-estimated. This method is based on a special class of transformation group, referred to as semi-affine transformation (SAT) group. The essence of this method is to create a joint distribution by translating the values of WVDs of Morlet wavelet to the positions around IFs of the best-matched elementary functions. Theoretical predictions and numerical results indicate that the proposed strategy can result in the most visually appealing TFDs for highly nonstationary signals. [Copyright &y& Elsevier]

Objective: Using network pharmacology and molecular docking methods, this study aimed to elucidate the key targets and molecular mechanisms of the Epimedium–Anemarrhen (EA) combination as a therapeutic approach for osteoporosis (OP). Methods: The TCMSP database was used to identify effective active ingredients and information on targets of EA according to the ADME threshold. An OP target database was established using the GeneCards, OMIM, DrugBank, and DisGeNET databases. The intersection of drug targets and disease targets was used to identify common genes, and protein interaction network, GO function enrichment, and KEGG signal pathway enrichment analyses were performed. A molecular docking analysis of active pharmaceutical ingredients with core genes was also conducted. Results: The analysis identified 30 effective active ingredients in EA and 149 common genes. A total of 20 core genes were identified by constructing a protein–protein interaction network and calculating the network topology parameters. An enrichment analysis revealed that these targets were primarily involved in biological functions and processes such as cell proliferation, apoptosis, inflammation, oxidative stress, and immunity. The signaling pathways associated with OP include the AGE-RAGE signaling pathway in relation to diabetes complications, the IL-17 signaling pathway, and the TNF signaling pathway. Molecular docking showed stable affinity between the core genes and most of the key components. Conclusion: These data provide mechanistic insights into the pharmacological activity of EA in the treatment of OP and provide an essential theoretical basis for clinical practice. [ABSTRACT FROM AUTHOR]

In the high bit-rate data compression, the filterbanks that match the statistical properties of inputs have been widely researched. For orthonormal uniform filterbanks and biorthogonal filterbanks without order constraints, the design problems have been solved on the whole. However, for biorthogonal FIR filterbanks, an efficient method associated with an algorithm for the design still needs to be developed. In this paper, two-channel adaptive biorthogonal filterbanks via lifting scheme are investigated. Starting from an arbitrary filterbank (orthonormal or biorthogonal), two-channel biorthogonal filterbanks are designed by the adaptive lifting scheme, which is a general form of our previous work. Two adaptive lifting algorithms are developed, namely, the sequential adaptive lifting and the joint adaptive lifting. Further, it is proved that starting from a linear-phase filterbank, the optimal filterbank by the sequential adaptive lifting preserves the linear-phase property. Experimental results show that the subband coding gains can be markedly improved when an appropriate initial filterbank is chosen. [Copyright &y& Elsevier]

Proposes a multistage decomposition algorithm for blind source separation. Derivation of single independent component; Comparison between the algorithm and jointly approximated diagonalization of eigen matrices; Estimation of unitary matrix.

Abstract: Low rank approximations of matrices have been widely used in pattern recognition and machine learning. Based on a sequence of matrices, a generalized low rank approximation problem was presented and an iterative scheme was given by Liang and Shi recently proposed an analytical scheme for this approximation problem. In this paper, we identify the weakness in their scheme and prove that their algorithm is incorrect. [Copyright &y& Elsevier]

• The viscoelastic behavior for rock mass of a circular tunnel supported with rock bolts was studied. • Focus on the distribution of rock mass stress and displacement of the coupled rheological model. • Discuss the coupled behavior of rock mass-rock bolts under a non-hydrostatic stress field. The stress and deformation characteristics of the rock mass and the rock bolt reinforcement structure change over time, as a result, it is of significance to understand the coupled rheological behavior of these two systems. In this paper, we first develop viscoelastic solutions for the rock mass reinforced by rock bolts under non-hydrostatic stresses based on the distributed force model. Subsequently, the Maxwell-Maxwell (M−M) and the Maxwell-Burgers (M−B) constitutive models are applied to the rock bolts and the rock mass, respectively, and the corresponding viscoelastic analytical solutions are then obtained. Finally, the numerical software FLAC3D is used to verify the fidelity of the mechanistic model. Our results show that the lateral pressure coefficient is positively correlated with the radial stress and the radial displacement. The radial stress in the rock mass reaches a stable value with time. Furthermore, the lateral pressure coefficient has a positive correlation with the axial force in the rock bolts in elastic analysis. However, as the creep in the rock mass develops, the axial forces under different lateral pressure coefficients gradually reach a stable value. Moreover, the lateral pressure coefficient mainly affects the distribution of axial force and the slope of the axial force in the rock bolts. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a genetic clustering algorithm is described that uses a new similarity measure based message passing between data points and the candidate centers described by the chromosome. In the new algorithm, a variable-length real-value chromosome representation and a set of problem-specific evolutionary operators are used. Therefore, the proposed GA with message-based similarity (GAMS) clustering algorithm is able to automatically evolve and find the optimal number of clusters as well as proper clusters of the data set. Effectiveness of GAMS clustering algorithm is demonstrated for both artificial and real-life data set. Experiment results demonstrated that the GAMS clustering algorithm has high performance, effectiveness and flexibility. [Copyright &y& Elsevier]