Recently, researchers in the artificial neural network field have focused their attention on connectionist models composed by several hidden layers. In fact, experimental results and heuristic ...considerations suggest that deep architectures are more suitable than shallow ones for modern applications, facing very complex problems, e.g., vision and human language understanding. However, the actual theoretical results supporting such a claim are still few and incomplete. In this paper, we propose a new approach to study how the depth of feedforward neural networks impacts on their ability in implementing high complexity functions. First, a new measure based on topological concepts is introduced, aimed at evaluating the complexity of the function implemented by a neural network, used for classification purposes. Then, deep and shallow neural architectures with common sigmoidal activation functions are compared, by deriving upper and lower bounds on their complexity, and studying how the complexity depends on the number of hidden units and the used activation function. The obtained results seem to support the idea that deep networks actually implements functions of higher complexity, so that they are able, with the same number of resources, to address more difficult problems.
•DFT and molecular docking studies were realized on synthesized novel Chalcone-DIM hybrids and Pirazoline-DIM hybrids compounds.•The title compounds were fully characterized by spectroscopy and ...spectrometric techniques (FT-IR 1H NMR, 13C NMR and HRMS-DART).•Some compounds showed antibacterial activity against Staphilococcus aureus ATCC6538 strain.•Theoretical studies revealed good π-cation, π-π and hydrogen bonding interactions with both catalytic and allosteric sites with PBP2 enzyme of S. aureus strain.
In this research we present the synthesis of a novel series of Pyrazoline-DIM hybrids compounds using microwave irradiation as activation energy, derived from their corresponding parent Chalcone-DIM hybrid, both with potential biological activity and not related to β-lactam antibiotics. The antibacterial activity of these compounds, against Staphylococcus aureus, has been investigated by means of in-vitro radial growth inhibition technique and supported by in-silico DFT methods, as well as molecular docking studies on the allosteric and catalytic sites of Penicillin-Binding Protein 2a. Biological activity seems to be correlated with HOMO location in the molecular structure, the HOMO-LUMO gap, softness and electrophilicity index. Docking studies reveal π-cation interactions as well as hydrogen bonds. These interactions and their frequency suggest that the biological activity of the synthetized molecules can be attributed mainly to interactions with the allosteric site instead of the catalytic one.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The detection of dim and small targets in the complex sea background poses new challenges to automatic target search and interception by infrared air-to-air missiles at sea. To solve the problems of ...low detection rate of dim targets and massive suspected targets caused by the shadow region of clutter on the sea surface, this paper proposes a detection method for dim and small targets with spatio-temporal features and background prior information. Firstly, by combining the ideas of local energy factor and multi-scale patch contrast measure, an improved dim target detection method is proposed, which can effectively enhance the contrast of dim targets and suppress background clutter. Then, according to the grayscale probability distribution difference between the background and the target, a double-Gaussian model is established for the residual background and the target region and a background suppression method based on the spatial prior information is proposed to further suppress the residual background. Finally, a dim target detection method is proposed by combining the above dim target detection, background suppression, and dynamic pipeline filtering methods. The results indicate the average detection rate of the detection method proposed in this study is 91.44%. Also, the average number of false alarms in a single frame is reduced to 9.89, which is more than 80% lower than that of other algorithms.
•Based on the local energy factor, an improved multi-scale patch contrast measure detection method is proposed for dim targets, which utilizes local dissimilarity and local brightness difference to effectively enhance dim targets and extract salient regions.•A background suppression method based on spatial prior information is proposed. The residual background is suppressed according to the difference of the grayscale probability distribution between the target and the background.•By considering the characteristics of the dynamic pipeline filter to correlate the motion trajectories, a spatio-temporal saliency detector MPCM-LEF fused with sea background prior information is proposed to effectively improve the detection rate of dim targets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In rheumatoid arthritis(RA) pathogenesis, activated RA fibroblast-like synoviocytes (RA-FLSs) exhibit similar proliferative features as tumor cells and subsequent erosion to cartilage will eventually ...lead to joint destruction. Therefore, it is imperative to search for compounds, which can effectively inhibit the abnormal activation of RA-FLSs, and retard RA progression.3'3-Diindolylmethane (DIM), the major product of the acid-catalyzed oligomerization of indole-3-carbinol from cruciferous vegetables, has been reported to be functionally relevant to inhibition of migration, invasion and carcinogenesis in some solid tumors. In this study, we explored the anti-proliferation, anti-metastasis and anti-inflammation effects of DIM on RA-FLSs as well as the underlying molecular mechanisms. To do this, primary RA-FLSs were isolated from RA patients and an animal model. Cell proliferation, migration and invasion were measured using CCK-8, scratch, and Transwell assays, respectively. The effects of DIM on Matrix metalloproteinases (MMPs) and some inflammatory factors mRNA and key molecules such as some inflammatory factors and those involved in aberrantly-activated signaling pathway in response to tumor necrosis factor α(TNF-α), a typical characteristic mediator in RA-FLS, were quantitatively measured by real-time PCR and western blotting. Moreover, the effect of DIM on adjuvant induced arthritis(AIA) models was evaluated with C57BL/6 mice
. The results showed that DIM inhibited proliferation, migration and invasion of RA-FLS
. Meanwhile, DIM dramatically suppressed TNF-α-induced increases in the mRNA levels of
, and
; as well as the proinflammatory factors
, and
β. Mechanistic studies revealed that DIM is able to suppress phosphorylated activation not only of p38, JNK in MAPK pathway but of AKT, mTOR and downstream molecules in the AKT/mTOR pathway. Moreover, DIM treatment decreased expression levels of proinflammatory cytokines in the serum and alleviated arthritis severity in the knee joints of AIA mice. Taken together, our findings demonstrate that DIM could inhibit proliferation, migration and invasion of RA-FLSs and reduce proinflammatory factors induced by TNF-α
by blocking MAPK and AKT/mTOR pathway and prevent inflammation and knee joint destruction
, which suggests that DIM might have therapeutic potential for RA.
Massive MIMO is a variant of multiuser MIMO (Multi-Input Multi-Output) system, where the number of basestation antennas M is very large and generally much larger than the number of spatially ...multiplexed data streams. Unfortunately, the front-end A/D conversion necessary to drive hundreds of antennas, with a signal bandwidth of 10 to 100 MHz, requires very large sampling bit-rate and power consumption. To reduce complexity, Hybrid Digital-Analog architectures have been proposed. Our work in this paper is motivated by one of such schemes named Joint Spatial Division and Multiplexing (JSDM), where the downlink precoder (resp., uplink linear receiver) is split into product of a baseband linear projection (digital) and an RF reconfigurable beamforming network (analog), such that only m ≪ M A/D converters and RF chains is needed. In JSDM, users are grouped according to similarity of their signal subspaces, and these groups are separated by the analog beamforming stage. Further multiplexing gain in each group is achieved using the digital precoder. Therefore, it is apparent that extracting the signal subspace of the M-dim channel vectors from snapshots of m-dim projections, with m ≪ M, plays a fundamental role in JSDM implementation. In this paper, we develop efficient subspace estimation algorithms that require sampling only m = O(2√M) antennas and, for a given p ≪ M, return a p-dim beamformer (subspace) that has a performance comparable with the best p-dim beamformer designed from the full knowledge of the exact channel covariance matrix. We assess the performance of our proposed estimators both analytically and empirically via numerical simulations.
Dim and small target detection in complex background is considered a difficult and challenging problem. Conventional algorithms using the local difference/mutation possibly produce high missed or ...mistaken detection rates. In this paper, we propose an effective algorithm for detecting dim and small infrared targets. In order to synchronously enhance targets and suppress complex background clutters, we adopt an adaptive entropy-based window selection technique to construct a novel local difference measure (LDM) map of an input image, which measures the dissimilarity between the current region and its neighboring ones. In this way, the window size can be adaptively regulated according to local statistical properties. Compared with the original image, the LDM map has less background clutters and noise residual. This guarantees the lower false alarm rates under the same probability of detection. Subsequently, a simple threshold is used to segment the target. More than 600 dim and small infrared target images against different complex and noisy backgrounds were utilized to validate the detection performance of the proposed approach. Extensive experimental results demonstrate that the proposed method not only works more stably for different target movements and signal-to-clutter ratio values, but also has a better performance compared with classical baseline methods. The evaluation results suggest that the proposed method is simple and effective with regard to detection accuracy.
•We present an adaptive entropy-based window selection scheme.•The novel local difference measure map can keep low false alarm rates under the same probability of detection.•The proposed method is simple and effective with regard to detection accuracy.
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Since their introduction, dye-sensitized solar cells (DSCs) have achieved huge success at a laboratory level. Recently, research is concentrated to visualize large DSC modules at the commercial ...platform. In that aspect, we have tested structurally simple porphyrin-based dye SK6 and anthracene-based dye CW10 for DSCs application under simulated 1 sun (AM 1.5G) and indoor light sources. These two dyes can be easily synthesized and yet are efficient with cell performances of ca. 5.42% and ca. 5.75% (without coadsorbent/additive) for SK6 and CW10, respectively, under AM 1.5G illumination. The power conversion efficiency (PCE) of SK6 reported in this work is the highest ever reported; this is achieved by optimizing the adsorption of SK6 on TiO2 photoanode using the most suitable solvent and immersion period. Cosensitization of SK6 with CW10 on TiO2 surface has boosted cell performance further and achieved PCE of ca. 6.31% under AM 1.5G illumination. Charge-transfer properties of individual and cosensitized devices at TiO2/dye/electrolyte interface were examined via electrochemical impedance spectroscopy. To understand the cell performances under ambient light conditions, we soaked individual and cosensitized devices under T5 and light-emitting diode light sources in the range of 300–6000 lx. The PCE of ca. 22.91% under T5 light (6000 lx) with J SC = 0.883 mA cm–2, V OC = 0.646 V, and FF = 0.749 was noted for the cosensitized device, which equals a power output of 426 μW cm–2. These results reveal that DSCs made of structurally simple dyes performed efficiently under both 1 sun (AM 1.5G) and indoor light conditions, which is undoubtedly a significant achievement when it comes to a choice of commercial application.
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IJS, KILJ, NUK, PNG, UL, UM
Robust detection of infrared dim and small target contributes significantly to the infrared systems in many applications. Due to the diversity of background scene and unique characteristic of target, ...the detection of infrared targets remains a challenging problem. In this paper, a novel approach based on total variation regularization and principal component pursuit (TV-PCP) is presented to deal with this problem. The principal component pursuit model only considers the low-rank feature of background images, which will result in poor detection ability in non-uniform and non-smooth scenes. We take into account the total variation regularization term to thoroughly describe background feature, which can achieve good detection result as well as good background estimation result. Firstly, the input infrared image is transformed to a patch image model. Secondly, the TV-PCP model is presented on the patch image. An effective optimization algorithm is proposed to solve this model. Experiments on six real datasets show that the proposed method has superior detection ability under various backgrounds, especially with good background suppression performance and low false alarm rate.
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•An infrared dim target detection method based on total variation regularization and principal component pursuit is proposed.•An optimization solver based on alternating direction method is proposed to solve the TV-PCP model.•By utilizing the total variation regularization, the TV-PCP performs well in target detection and background estimation.
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Abstract Security postulates of visible light communication (VLC) is a paramount area of consideration due to its deployment in military, businesses, and residential establishments. Optical code ...division multiplexing (OCDMA) is prominent multiples access technique to serve multiple users and offer better security as compared to other available techniques such as wavelength and time division multiplexing (TDM). Wavelength conversion, multicode keying, optical logic gates, and quantum key distribution are some of the widely used security enhancement techniques but come at high cost and greater complexity. Zero cross correlation codes (ZCC) with integration of time dimension is an ultimate solution to the complex security improvement techniques but conventional two dimensional (2D) ZCC codes has an utmost issue of adjacent weights (W) and time (t) in the code which can be easily decoded by eavesdropper. Therefore, in this work, a novel weight managed ZCC (WMZCC) OCDMA code is presented with the non-adjacent W and t in the code matrix for making authentic information decoding difficult. Proposed 2D-WMZCC codes are investigated for 5 users at 100 Gbps over VLC link length of 5 m using polarization division multiplexed (PDM) quadrature phase shift keying (QPSK) and digital signal processing in terms of log symbol error rate (log SER), Q factor and bit error rate (BER). Further, a detailed comparison of 2D-WMZCC codes is performed with existing 2D diagonal identity matrix (DIM) codes and results revealed that former one exhibits better security than later OCDMA code.
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