An augmented lagrangian method for sparse SAR imaging

In this paper, we present a solution to the constrained l1-norm minimization problem for sparse SAR imaging. The technique we present relies on recent advances in the solution of optimization problems, based on Augmented Lagrangian Methods (ALMs), namely the Alternating Direction Method of Multipliers. Here, we present an application of C-SALSA (an ALM for constrained optimization problems) to SAR imaging, and introduce a new weighting scheme to improve the sparsity of the reconstructions. We then compare the performances of several techniques to understand the effectiveness of ALMs in the context of SAR imaging

An augmented Lagrangian method for image reconstruction with multiple features

We present an Augmented Lagrangian Method (ALM) for solving image reconstruction problems with a cost function consisting of multiple regularization functions with a data fidelity constraint. The presented technique is used to solve inverse problems related to image reconstruction, including compressed sensing formulations. Our contributions include an improvement for reducing the number of computations required by an existing ALM method, an approach for obtaining the proximal mapping associated with p-norm based regularizers, and lastly a particular ALM for the constrained image reconstruction problem with a hybrid cost function including a weighted sum of the p-norm and the total variation of the image. We present examples from Synthetic Aperture Radar imaging and Computed Tomography

Autofocused compressive SAR imaging based on the alternating direction method of multipliers

We present an alternating direction method of multipliers (ADMM) based autofocused Synthetic Aperture Radar (SAR) imaging method in the presence of unknown 1-D phase errors in the phase history domain, with undersampled measurements. We formulate the problem as one of joint image formation and phase error estimation. We assume sparsity of strong scatterers in the image domain, and as such use sparsity priors for reconstruction. The algorithm uses l(p)-norm minimization (p <= 1) [8] with an improvement by integrating the phase error updates within the alternating direction method of multipliers (ADMM) steps to correct the unknown 1-D phase error. We present experimental results comparing our proposed algorithm with a coordinate descent based algorithm in terms of convergence speed and reconstruction quality

Detection of 13th chromosome deletion frequency by fluorescent in situ hybridization method in patients with multiple myeloma

INTRODUCTION: Multiple myeloma (MM) is a malignant hematological disease characterized by malignant proliferation of a single plasma cell clone leading to monoclonal protein in plasma or urine. Presence of monoallelic loss of chromosome 13 (del13) or loss of long arm (del13q) indicates poor prognostic outcome in patients treated with standard chemotherapy. Del13/del13q is detected by FISH method in approximately half of newly diagnosed MM patients. METHODS: 42 patients diagnosed with MM according to the criteria of the International myeloma working group and treated at research and education hospital, were included in this study. Clinical, laboratory, pathological data were analyzed retrospectively and genetic data obtained by FISH method. RESULTS: 26 patients were female (61.9%) and 16 were male (38.1%). The mean age was 62. Del13 results were obtained in 30 of 42 patients, while positive in 6 patients (20%) negative in 24 patients (80%). Among the 30 patients with chromosome 13 results, 4 had IgA, 19 had IgG type monoclonal protein. All of the 6 patients with del13 were IgG myeloma (2 kappa, 3 lambda). DISCUSSION AND CONCLUSION: Compared to the recent studies, del13 is lower in our study. In many studies, del13 has been found in rates ranging from 30-50%. Although the rate of 20% we found is lower than the data in the literature, it is valuable in terms of reflecting the frequency of del13 in myeloma patients. Therefore, we strongly recommend that conventional karyotyping and FISH analysis of common chromosomal abnormalities be performed in newly diagnosed MM patients

An augmented Lagrangian method for autofocused compressed SAR imaging

We present an autofocus algorithm for Compressed SAR Imaging. The technique estimates and corrects for 1-D phase errors in the phase history domain, based on prior knowledge that the reflectivity field is sparse, as in the case of strong scatterers against a weakly-scattering background. The algorithm relies on the Sparsity Driven Autofocus (SDA) method and Augmented Lagrangian Methods (ALM), particularly Alternating Directions Method of Multipliers (ADMM). In particular, we propose an ADMM-based algorithm that we call Autofocusing Iteratively Re-Weighted Augmented Lagrangian Method (AIRWALM) to solve a constrained formulation of the sparsity driven autofocus problem with an ℓp-norm, p ≤ 1 cost function. We then compare the performance of the proposed algorithm's performance to Phase Gradient Autofocus (PGA) and SDA [2] in terms of autofocusing capability, phase error correction, and computation time

A fast augmented Lagrangian approach for compressed SAR imaging

In this paper we present an accelerated Augmented Lagrangian Method for the solution of constrained convex optimization problems in the Basis Pursuit De-Noising (BPDN) form. The technique relies on on Augmented Lagrangian Methods (ALMs), particularly the Alternating Direction Method of Multipliers (ADMM). Here, we present an application of the Constrained Split Augmented Lagrangian Shrinkage Algorithm (C-SALSA) to SAR imaging, while introducing a method to handle complex SAR imagery in the constrained Total Variation Minimization formulation. In addition, we apply acceleration schemes to C-SALSA to obtain faster convergence of the method; such as used in Fast ADMM methods proposed by Goldstein et al., in the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) proposed by Beck and Teboulle, and in NESTA proposed by Becker et al. We present examples to illustrate the effectiveness of Accelerated C-SALSA in the context of SAR imaging

An alternating direction method of multipliers for sparse SAR imaging (Seyrek SAR görüntüleme için yön değiştiren çarpanlar yaklaşımı)

In this paper, we present a solution to the constrained 1-norm minimization problem for sparse SAR imaging. The technique we present relies on recent advances in the solution of optimization problems, based on Augmented Lagrangian Methods (ALMs), in particular the Alternating Direction Method of Multipliers. Here, we present an application of C-SALSA (an ALM for constrained optimization problems) to SAR imaging. We then compare the performances of several techniques to understand the effectiveness of ALMs in the context of SAR imaging

Nonomuraea basaltis sp. nov., a siderophore-producing actinobacteria isolated from surface soil of basaltic parent material

A Gram-stain-positive, aerobic, spore-forming actinobacterial strain, designated 160415(T), was isolated from a surface soil sample, which was formed on basaltic parent material, collected from Samsun, Turkey. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 160415(T) clustered closely with species of the genus Nonomuraea, and showed the highest sequence similarity to Nonomuraea zeae NEAU-ND5(T), Nonomuraea candida HMC10(T) and Nonomuraea turkmeniaca DSM 43926(T) with 99.1%, 98.9% and 98.7%, respectively. Chemotaxonomic properties including major menaquinones, diaminopimelic acid, sugar and phospholipid profiles also confirmed the affiliation of the strain to the genus Nonomuraea. The DNA G+C content of strain 160415(T) was 69.6 mol%. DNA-DNA hybridization and average nucleotide identity values between the strain and closely related type strains were less than the recommended cut-off values. On the basis of phylogenetic relationships, genotypic and phenotypic characterizations, strain 160415(T) represents a novel species of the genus Nonomuraea, for which the name Nonomuraea basaltis sp. nov. is proposed. The type strain is 160415(T) (= KCTC 39875(T) = DSM 104309(T))

Active control of focal length and beam deflection in a metallic nano-slit array lens with multiple sources

We propose a surface plasmon-polariton based nano-rod array lens structure that incorporates two additional lateral input channels, with the ability to control the focal length and the deflection of the transmitted beam through the lens actively by the intensity of the channel sources. We demonstrate by numerical simulations that, applying the sources with the same intensity can change the focal point and the beam waist, whereas unequal intensities generate an asymmetric field profile in the nano-rod array inducing an off-axis beam deflection.Comment: 4 pages, 5 figure