Space-Time Transmit-Receive Design for Colocated MIMO Radar

This chapter deals with the design of multiple input multiple-output (MIMO) radar space-time transmit code (STTC) and space-time receive filter (STRF) to enhance moving targets detection in the presence of signal-dependent interferences, where we assume that some knowledge of target and clutter statistics are available for MIMO radar system according to a cognitive paradigm by using a site-specific (possible dynamic) environment database. Thus, an iterative sequential optimization algorithm with ensuring the convergence is proposed to maximize the signal to interference plus noise ratio (SINR) under the similarity and constant modulus constraints on the probing waveform. In particular, each iteration of the proposed algorithm requires to solve the hidden convex problems. The computational complexity is linear with the number of iterations and polynomial with the sizes of the STTW and the STRF. Finally, the gain and the computation time of the proposed algorithm also compared with the available methods are evaluated

Caractérisation et traitement potentiel de la dégénérescence rétinienne dans quatre modèles de souris de ciliopathies emblématiques

Les ciliopathies rétiniennes sont un groupe de maladies rares causés par des mutations de gènes ciliaires. Les défauts des gènes ciliaires peuvent causer des défauts de trafic de protéines et induit l'apoptose des cellules photoréceptrices causés par le stress du réticulum endoplasmique (RE). On a étudié ciliopathies rétiniennes par modèle mourin, amaurose congénitale de Leber, rétinopathie pigmentaire liée à l’X, syndrome de Bardet-Biedl, syndrome d’Alström. Les souris Bbs1-/- , Bbs10-/- et CEP290-/- ont monté une diminution de la fonction rétinienne et sont causée par ER stress. Les souris Rd9/y et Alms1foz/foz présentent une apparition tardive et avec un faible taux de dégénérescence rétinienne et ils pourrait être causée par d'autres mécanismes. Le traitement GV-Ret basé sur le stress du RE pourrait sauver à la fois la fonction de et la morphologie de la rétine dans souris BBS.Retinal ciliopathies are a group of rare diseases caused by mutations of ciliary genes. Defects in ciliary genes can cause defects in proteins traffics and induces apoptosis of photoreceptor cells caused by stress of the endoplasmic reticulum (ER) .We studied retinal ciliopathies by mice models, Leber congenital amaurosis, Xlinked retinitis pigmentosa, Bardet-Biedl syndrome and Alström Syndrome. The Bbs1-/-, Bbs10-/- and CEP290-/- mice exhibited a decrease in retinal function caused by ER stress. Rd9/y and Alms1foz/foz mice showed a late onset and a low rate of retinal degeneration and they could be caused by other mechanisms. The GV-Ret treatment based on ER stress could save both the function and morphology of the retina in BBS mice

Interplay between miRNAs and lncRNAs: Mode of action and biological roles in plant development and stress adaptation

Plants employ sophisticated mechanisms to control developmental processes and to cope with environmental changes at transcriptional and post-transcriptional levels. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs), two classes of endogenous noncoding RNAs, are key regulators of gene expression in plants. Recent studies have identified the interplay between miRNAs and lncRNAs as a novel regulatory layer of gene expression in plants. On one hand, miRNAs target lncRNAs for the production of phased small interfering RNAs (phasiRNAs). On the other hand, lncRNAs serve as origin of miRNAs or regulate the accumulation or activity of miRNAs at transcription and post-transcriptional levels. Theses lncRNA miRNA interplays are crucial for plant development, physiology and responses to biotic and abiotic stresses. In this review, we summarize recent advances in the biological roles, interaction mechanisms and computational predication methods of the interplay between miRNAs and lncRNAs in plants

A Sequential Optimization Calibration Algorithm for Near-Field Source Localization

This paper considers the near-field source location problem for a nonuniform linear array (non-ULA) in the presence of sensor gain and phase errors. A sequential optimization calibration method is proposed to simultaneously estimate the gain and phase errors as well as the locations of calibration sources involving the ranges and the azimuths by exploiting some imprecise a-priori knowledge of calibration sources. At each iteration of the proposed method, the source locations, and the gain and phase errors are obtained iteratively. Finally, at the analysis stage, we evaluate the effectiveness of the proposed technique using some numerical simulations. Results show that the proposed algorithm shares the capability to jointly estimate the source locations and the errors

Robust Design of Constant Modulus Sequence and Receiver Filter in the Presence of Signal-dependent Clutter

In this paper, we focus on the detection of a moving point-like target embedded in uncertain signal-dependent clutter and develop robust transmit-code and receive-filter designs in slow-time. First, based on the Worst-case Signal-to-Interference-plus-Noise Ratio (W-SINR) when the second-order clutter statistics are uncertain, we establish a high-dimensional transmit-receive optimization model that considers the constant modulus constraint with non-convexity. Next, we propose an Iterative Sequential Optimization (ISO) algorithm. At each iteration, it converts a high-dimensional optimization into multiple one-dimensional fractional programming problems that can be efficiently solved using Dinkelbach’s method. Finally, we use numerical examples to confirm that the ISO can resist the uncertain knowledge of signal-dependent clutter, which enables the radar system to adapt to complicated environments. Moreover, compared to Semi-Definite Relaxation (SDR)-related and randomization methods, the proposed algorithm is superior with respect to both optimized W-SINR and computational time

Optimization of Sparse Planar Arrays with Minimum Spacing and Geographic Constraints in Smart Ocean Applications

Sparse arrays can fix array aperture with a reduced number of elements to maintain resolution while reducing cost. However, grating lobe suppression, high peak side-lobe level reduction (PSLL), and constraints on the location of the array elements in the practical deployment of arrays are challenging problems. Based on simulated annealing, the element locations of a sparse planar array in smart ocean applications with minimum spacing and geographic constraints are optimized in this paper by minimizing the sum of PSLL. The robustness of the deployment-optimized spare planar array with mis-calibration is further considered. Numerical simulations show the effectiveness of the proposed solution