| 1. |
|
|
| 2. |
- Bravo, L, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 3. |
- Tabiri, S, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 4. |
|
|
| 5. |
- Glasbey, JC, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Malek-Mohammadi, Mohammadreza, et al.
(författare)
-
Successive Concave Sparsity Approximation for Compressed Sensing
- 2016
-
Ingår i: IEEE Transactions on Signal Processing. - 1053-587X .- 1941-0476. ; 64:21, s. 5657-5671
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, based on a successively accuracy-increasing approximation of the l(0) norm, we propose a new algorithm for recovery of sparse vectors from underdetermined measurements. The approximations are realized with a certain class of concave functions that aggressively induce sparsity and their closeness to the l(0) norm can be controlled. We prove that the series of the approximations asymptotically coincides with the l(1) and l(0) norms when the approximation accuracy changes from the worst fitting to the best fitting. When measurements are noise-free, an optimization scheme is proposed that leads to a number of weighted l(1) minimization programs, whereas, in the presence of noise, we propose two iterative thresholding methods that are computationally appealing. A convergence guarantee for the iterative thresholding method is provided, and, for a particular function in the class of the approximating functions, we derive the closed-form thresholding operator. We further present some theoretical analyses via the restricted isometry, null space, and spherical section properties. Our extensive numerical simulations indicate that the proposed algorithm closely follows the performance of the oracle estimator for a range of sparsity levels wider than those of the state-of-the-art algorithms.
|
|
| 9. |
- Meghdadi, S., et al.
(författare)
-
Synthesis, X-ray crystal structure, and electrochemistry of copper(II) complexes of a new tridentate unsymmetrical Schiff base ligand and its hydrolytically rearranged isomer
- 2012
-
Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693. ; 385, s. 31-38
-
Tidskriftsartikel (refereegranskat)abstract
- A new unsymmetrical Schiff base ligand HL1, HBacabza, and its copper(II) complexes [Cu2L21(OAc)(2)] (1) and [Cu2L22(N-3)(2)]center dot 2H(2)O (2) with HBacabza = 3-(2- aminobenzylimino)-1-phenylbutan-1-one as HL1 and its hydrolytically rearranged isomer 3-(2-aminomethylphenyleneimino)-1-phenylbutan-1-one as HL2, have been synthesized and characterized by elemental analyses and spectroscopic methods. The rearrangement of HL1 to HL2 occurs in a hydrolysis-recondensation process in the reaction of HL1 with Cu(ClO4)(2)center dot 6H(2)O and NaN3. The crystal structures of the ligand and its complexes have been determined by single crystal X-ray diffraction. The deprotonated Bacabza coordinates to the metal center as a tridentate ligand. The acetate anion coordinates through one oxygen atom in complex 1 leading to a mono-atomic acetate oxygen-bridging dimeric copper(II) complex. Similarly, the azide anion coordinates through one nitrogen atom in complex 2 leading to a mono-atomic azide nitrogen-bridging dimeric copper(II) complex. The copper(II) ions adopt a distorted square pyramidal (4 + 1) coordination in these two complexes. The cyclic voltammetric studies of these complexes in N, N-dimethylformamide indicate that the reduction process corresponding to Cu-II/Cu-I is electrochemically irreversible in complex 1, presumably due to the structural changes during the course of redox reaction, and quasi-reversible in complex 2.
|
|
