Combinatorial Optimization of the piecewise constant Mumford-Shah functional with application to scalar/vector valued and volumetric image segmentation

Front propagation models represent an important category of image segmentation techniques in the current literature. These models are normally formulated in a continuous level sets framework and optimized using gradient descent methods. Such formulations result in very slow algorithms that get easily stuck in local solutions and are highly sensitive to initialization.In this paper, we reformulate one of the most influential front propagation models, the Chan-Vese model, in the discrete domain. The graph representability and submodularity of the discrete energy function is established and then max-flow/min-cut approach is applied to perform the optimization of the discrete energy function. Our results show that this formulation is much more robust than the level sets formulation. Our approach is not sensitive to initialization and provides much faster solutions than level sets. The results also depict that our segmentation approach is robust to topology changes, noise and ill-defined edges, i.e., it preserves all the advantages associated with level sets methods.     

Broadband Transmitarray for Satellite Applications in Ku Band

Wireless Personal Communications - This paper focuses on the user-pair association for multi-tier relay-based dual-hop heterogeneous networks (HetNets) and proposes a novel min–max user-pair...     

Importance of the Long-Chain Fatty Acid Beta-Hydroxylating Cytochrome P450 Enzyme YbdT for Lipopeptide Biosynthesis in Bacillus subtilis Strain OKB105

Bacillus species produce extracellular, surface-active lipopeptides such as surfactin that have wide applications in industry and medicine. The steps involved in the synthesis of 3-hydroxyacyl-coenzyme A (CoA) substrates needed for surfactin biosynthesis are not understood. Cell-free extracts of Bacillus subtilis strain OKB105 synthesized lipopeptide biosurfactants in presence of l-amino acids, myristic acid, coenzyme A, ATP, and H(2)O(2), which suggested that 3-hydroxylation occurs prior to CoA ligation of the long chain fatty acids (LCFAs). We hypothesized that YbdT, a cytochrome P450 enzyme known to beta-hydroxylate LCFAs, functions to form 3-hydroxy fatty acids for lipopeptide biosynthesis. An in-frame mutation of ybdT was constructed and the resulting mutant strain (NHY1) produced predominantly non-hydroxylated lipopeptide with diminished biosurfactant and beta-hemolytic activities. Mass spectrometry showed that 95.6% of the fatty acids in the NHY1 biosurfactant were non-hydroxylated compared to only ～61% in the OKB105 biosurfactant. Cell-free extracts of the NHY1 synthesized surfactin containing 3-hydroxymyristic acid from 3-hydroxymyristoyl-CoA at a specific activity similar to that of the wild type (17 ± 2 versus 17.4 ± 6 ng biosurfactant min(-1)·ng·protein(-1), respectively). These results showed that the mutation did not affect any function needed to synthesize surfactin once the 3-hydroxyacyl-CoA substrate was formed and that YbdT functions to supply 3-hydroxy fatty acid for surfactin biosynthesis. The fact that YbdT is a peroxidase could explain why biosurfactant production is rarely observed in anaerobically grown Bacillus species. Manipulation of LCFA specificity of YbdT could provide a new route to produce biosurfactants with activities tailored to specific functions.     

Novel anticorrosive emulsion-type paints containing organic/inorganic nanohybrid particles

Novel anticorrosive emulsion-type paints were prepared by utilizing organic/inorganic nanohybrid particles (nHPs) of composition (1:1) based on polyaniline (PANI) and nanosilica. Polyaniline (PANI) and nanosilica were synthesized via chemical oxidative and sol–gel polymerization techniques respectively. The prepared materials were characterized via (gel permeation chromatography (GPC), infra red (FT-IR), transmission electron microscope (TEM) and differential scanning calorimetry (DSC)). The binder used in this context is polyvinyl acetate (PVAc). Nanohybrid particles/PVAc emulsion composites (nHPs ECs) were simply formed by individual mixing of the prepared neat PANI and nHPs of composition (1:1) with PVAc to produce the corresponding nanohybrid particles/PVAc emulsion composites EC₁ and EC₂ respectively. The chemical and basic properties including (acid and alkali resistance, adhesion, washability, gloss, opacity, whiteness, hardness, impact, and weathering) as well as the anticorrosion properties of the blank paint films and the paint films containing neat PANI and nHPs of different concentrations (5%, 10%, and 15%) were investigated and evaluated. The obtained experimental results revealed that the presence of nHPs in the blank paint are highly enhanced both basic and anticorrosion properties of the coated films.     

New insights in structural characterization of transparent ZnS ceramics hot-pressed from nanocrystalline powders synthesized by combustion method

Zinc sulfide transparent ceramics have been fabricated by hot pressing (HP) powders prepared by a newly developed combustion method. Chemical, structural and microstructural properties of powders and ceramics were characterized using different experimental techniques (XRD, SEM-EDS, laser granulometry, TEM, BET, FT-IR spectroscopy). ZnS powders were densified to full density by HP under vacuum atmosphere. The ceramics exhibit highly dense microstructure with mean grain size of 1 μm. TEM characterization identified, both in powders and ceramics, twins and simple stacking faults due to the aperiodic distribution of hexagonal domains. With optical transmission of the theoretical level (～75%), without absorption band (at 6 μm) and with negligible optical loss, in the 4–12 μm region, the ceramics exhibit better optical performances than standard grade CVD ZnS, and unprecedented performances for hot-pressed ZnS.     

Dual-Band Antenna Array with Reduced Mutual-Coupling for Wearable Wireless Communication Applications

In this paper, dual-band wearable microstrip patch antenna printed on FR4-substrate is designed and fabricated for wearable wireless communications. A star-shaped monopole Ω antenna connected to 50 Ω transmission line, backed by partial ground plane is used. The antenna dimensions are optimized for wideband radiation characteristics. Different types of dielectric substrates are investigated for wideband wearable applications. The proposed antenna printed on jeans textile substrate introduces an impedance matching bandwidth of 7.3 GHz with maximum gain of 5 dBi. The effect of mutual coupling between two parallel patches, two opposite patches and two orthogonal patches on their radiation characteristics are investigated. High isolation is achieved for two orthogonal patches placed away from each other by 0.3λ with a rectangular strip etched between them and cutting in the ground plane. The isolation is below ? 29 dB within the frequency band. The structure achieves impedance matching bandwidth of 1.8 GHz in 1st-band and 4.8 GHz in 2nd-band with maximum gains of 8.5 dBi and 5.3 dBi, respectively. A prototype element is fabricated, measured and the radiation characteristics coincide with the simulated results. The structure is simple, light-weight, and is suitable for WAN applications in the frequency band from 2 GHz to 7 GHz. The effect of human body tissue on the radiation characteristics of the antenna array is investigated. 

     

通过FPGA设计安全的高级辅助驾驶系统

正随着道路上汽车数量的增加,我们需要更多的技术来进一步减少交通事故。过去几年,基于雷达和摄像机的新系统功能的出现使驾驶更加安全。很多高级辅助驾驶系统(ADAS)应用,如自动巡航控制、道路偏离报警、交通信号标志识别等,已经成为车辆上非常方便的功能,但对车辆行为没有影响或影响很小。然而,现在这些技术开始在车辆控制中扮演积极主动的角色,如车道辅助保持     

Prediction of water and protein contents and quality classification of Spanish cooked ham using NIR hyperspectral imaging

This study was carried out to investigate the ability of hyperspectral imaging technique in the NIR spectral region of 900–1700 nm for the prediction of water and protein contents in Spanish cooked hams. Multivariate analyses using partial least-squares regression (PLSR) and partial least squares-discriminant analysis (PLS-DA) were applied to the spectral data extracted from the images to develop statistical models for predicting chemical attributes and classify the different qualities. Feature-related wavelengths were identified for protein (930, 971, 1051, 1137, 1165, 1212, 1295, 1400, 1645 and 1682 nm) and water (930, 971, 1084, 1212, 1645 and 1682 nm) and used for regression models with fewer predictors. The PLS-DA model using optimal wavelengths (966, 1061, 1148, 1256, 1373 and 1628 nm) successfully classified the examined hams in different quality categories. The results revealed the potentiality of NIR hyperspectral imaging technique as an objective and non-destructive method for the authentication and classification of cooked hams.     

Effect of combining Al,Mg, Ce or La oxides to extracted rice husk nanosilica on the catalytic performance of NiO during COx-free hydrogen production via methane decomposition

Amorphous nanosilica powder was extracted from rice husk and used as a catalyst support as well as a starting material for the preparation of different binary oxides, i.e., SiO₂Al₂O₃, SiO₂MgO, SiO₂CeO₂ and SiO₂La₂O₃. A series of supported nickel catalysts with the metal loading of 50 wt % were prepared by wet impregnation method and evaluated in methane decomposition to “CO_x-free” hydrogen production. The fresh and spent catalysts were extensively characterized by different techniques. Among the evaluated catalysts, both Ni/SiO₂Al₂O₃ and Ni/SiO₂La₂O₃ catalysts were the most active with an over-all H₂ yield of ca. 80% at the initial period of the reaction. This distinguishable higher catalytic activity is mainly referred to the presence of free mobile surface NiO and/or that NiO fraction weakly interacted with the support easily reducible at low temperatures. The Ni/SiO₂CeO₂ catalyst has proven a great potential for application in the hydrogen production in terms of its catalytic stability. The formation of Mg_xNi_(1?x)O solid solution caused the Ni/SiO₂MgO catalyst to lose its activity and stability at a long reaction time. Various types of carbon materials were formed on the catalyst surface depending on the type of support used. TEM images of as-deposited carbon showed that multi-walled carbon nanotubes (MWCNTs) and graphene platelets were formed on Ni/SiO₂, while only MWCNTs were deposited on all binary oxide supported Ni catalysts.