Moving Object Detection in Complex Scene Using Spatiotemporal Structured-Sparse RPCA

Javed, Sajid,Mahmood, Arif,Al-Maadeed, Somaya,Bouwmans, Thierry,Jung, Soon Ki IEEE 2019 IEEE TRANSACTIONS ON IMAGE PROCESSING - Vol.28 No.2

<P>Moving object detection is a fundamental step in various computer vision applications. <I>Robust principal component analysis</I> (RPCA)-based methods have often been employed for this task. However, the performance of these methods deteriorates in the presence of dynamic background scenes, camera jitter, camouflaged moving objects, and/or variations in illumination. It is because of an underlying assumption that the elements in the sparse component are mutually independent, and thus the spatiotemporal structure of the moving objects is lost. To address this issue, we propose a spatiotemporal structured sparse RPCA algorithm for moving objects detection, where we impose spatial and temporal regularization on the sparse component in the form of graph Laplacians. Each Laplacian corresponds to a multi-feature graph constructed over superpixels in the input matrix. We enforce the sparse component to act as eigenvectors of the spatial and temporal graph Laplacians while minimizing the RPCA objective function. These constraints incorporate a spatiotemporal subspace structure within the sparse component. Thus, we obtain a novel objective function for separating moving objects in the presence of complex backgrounds. The proposed objective function is solved using a linearized alternating direction method of multipliers based batch optimization. Moreover, we also propose an online optimization algorithm for real-time applications. We evaluated both the batch and online solutions using six publicly available data sets that included most of the aforementioned challenges. Our experiments demonstrated the superior performance of the proposed algorithms compared with the current state-of-the-art methods.</P>

Electrospun PVDF/ZnO Based Composite Fibers for Oil Absorption and Photocatalytic Degradation of Organic Dyes from Waste Water

Hemalatha Parangusan,Jolly Bhadra,Zubair Ahmad,Ali S. M A Al-Maadeed,Abdulaziz M. A A Al-Mohannadi,Noora Al-Thani 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

Clean drinking water has been a vital topic of research in modern world, this makes efficient water purification asthe latest demand. The research and development in the field of filtration technology has revitalize considerable awareness indifferent engineered methods and nanomaterials. In this work, a hydrophobic composite fibers was successfully prepared byincorporating ZnO nanofiller into polyvinylidene fluoride (PVDF) using an electrospinning method for organic dyedegradation and oil absorption applications. The hydrothermal method was used to prepare pure ZnO. The structuralproperties of PVDF/ZnO composite fibers and pure ZnO were studied using the X-ray diffraction technique (XRD). TheSEM image of pure ZnO shows a flower-like structure and the composites exhibited the structure of the fibers. The averagefiber diameter of the pure PVDF fiber was around 625 nm and the PVDF/ZnO composite fiber was around 485 nm,respectively. Finally, the prepared fibers were tested for oil absorption and the photocatalytic degradation of organic dyes. The photocatalytic activity of PVDF/ZnO was evaluated by the degradation of Azocarmine G (AZG) and Malachite green(MG) dye under sunlight irradiation. The results showed that 85 % of AZG and 90 % of MG dye could be degraded within120 min and 240 min. It was found that the PVDF/ZnO composite fiber was hydrophobic (135 °) under water. Good oilabsorption efficiency (115 %) was achieved using PVDF/ZnO composite fibers. The results shows that the preparedcomposite fibers can be used to absorb oil and degrade organic contaminants. This cost-effective, easy operation, reusability,and efficiency of the PVDF/ZnO fiber mats could be potentially useful for water treatment and oil recovery.

Unveiling the sodium intercalation properties in Na_1.86□_0.14Fe₃(PO₄)₃

Essehli, R.,Ben Yahia, H.,Maher, K.,Sougrati, M.T.,Abouimrane, A.,Park, J.-B.,Sun, Y.-K.,Al-Maadeed, M.A.,Belharouak, I. Elsevier Sequoia 2016 Journal of Power Sources Vol. No.

<P><B>Abstract</B></P> <P>The new compound Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> was successfully synthesized via hydrothermal synthesis and its crystal structure was determined using powder X-ray diffraction data. Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> was also characterized by operando XRD and Mössbauer spectroscopy, cyclic voltammetry, and galvanostatic cycling. Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> crystallizes with the alluaudite-type structure with the eight coordinated Na1 and Na2 sodium atoms located within the channels. The combination of the Rietveld- and Mössbauer-analyses confirms that the sodium vacancies in the Na1 site are linked to a partial oxidation of Fe<SUP>2+</SUP> during synthesis. The electrochemical tests indicated that Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> is a 3 V sodium intercalating cathode. At the current densities of 5, 10, and 20 mA g<SUP>−1</SUP>, the material delivers the specific capacities of 109, 97, and 80 mA h g<SUP>−1</SUP>, respectively. After 100 charge and discharge cycles, Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> exhibited good sodium removal and uptake behavior although no optimizations of particle size, morphology, and carbon coating were performed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> was synthesized via hydrothermal synthesis method. </LI> <LI> Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> crystallizes with the Alluaudite-type structure. </LI> <LI> Operando in situ XRD and Mössbauer spectroscopy studies were carried on. </LI> <LI> The crystal structure of Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> is stable during cycling. </LI> <LI> Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> is a promising 3 V cathode material for sodium ion batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Na1.86□0.14Fe3(PO4)3 was synthesized via hydrothermal synthesis method. Na1.86Fe3(PO4)3 crystallizes with the alluaudite-type structure. Na1.86Fe3(PO4)3 is a 3 V sodium intercalating cathode. At the current densities of 5, 10, and 20 mA g<SUP>−1</SUP>, the material delivers the specific capacities of 109, 97, and 80 mA h g<SUP>−1</SUP>, respectively. After 100 charge and discharge cycles, Na1.86Fe3(PO4)3 exhibited good sodium removal and uptake behavior with a stable crystal structure.</P> <P>[DISPLAY OMISSION]</P>

Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr₂(PO₄)₃, NaNiCr₂(PO₄)₃, and Na₂Ni₂Cr(PO₄)₃

Yahia, H.B.,Essehli, R.,Avdeev, M.,Park, J.B.,Sun, Y.K.,Al-Maadeed, M.A.,Belharouak, I. Academic Press 2016 Journal of solid state chemistry Vol.238 No.-

<P>The new compounds NaCoCr2(PO4)(3), NaNiCr2(PO4)(3), and Na2Ni2Cr(PO4)(3) were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr2(PO4)(3), NaNiCr2(PO4)(3), and Na2Ni2Cr(PO4)(3) crystallize with a stuffed alpha-CrPO4-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr2(PO4)(3), and Na2Ni2Cr(PO4)(3) a statistical disorder Ni2+/Cr3+ was observed on both the 8g and 4a atomic positions, whereas in NaCoCr2(PO4)(3) the statistical disorder Co2+/Cr3+ was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr2(PO4)(3), NaNiCr2(PO4)(3), and Na2Ni2Cr(PO4)(3) delivered specific capacities of 352, 385, and 368 mA h g(-1), respectively, which attests to the electrochemical activity of sodium in these compounds. (C) 2016 Elsevier Inc. All rights reserved.</P>