An Open Source Testing Tool for Evaluating Handwriting Input Methods

This paper presents an open source tool for testing the recognition accuracy of Chinese handwriting input methods. The tool consists of two modules, namely the PC and Android mobile client. The PC client reads handwritten samples in the computer, and transfers them individually to the Android client in accordance with the socket communication protocol. After the Android client receives the data, it simulates the handwriting on screen of client device, and triggers the corresponding handwriting recognition method. The recognition accuracy is recorded by the Android client. We present the design principles and describe the implementation of the test platform. We construct several test datasets for evaluating different handwriting recognition systems, and conduct an objective and comprehensive test using six Chinese handwriting input methods with five datasets. The test results for the recognition accuracy are then compared and analyzed.Comment: 5 pages, 3 figures, 11 tables. Accepted to appear at ICDAR 201

Galangin Alleviates Liver Ischemia-Reperfusion Injury in a Rat Model by Mediating the PI3K/AKT Pathway

Background/Aims: Liver ischemia-reperfusion (I/R) injury is a pathological process that often occurs during liver and trauma surgery. There are numerous causes of liver I/R injury, but the mechanism is unknown. Galangin (GA) is a flavonoid, a polyphenolic compound widely distributed in medicinal herbs that has anti-inflammatory, antioxidant, and antitumor activity. This study evaluated the protective effect of GA on hepatic I/R injury. Methods: An I/R model was created in male Wistar rats by clamping the hepatoportal vein, hepatic artery and hepatic duct for 30 min followed by reperfusion for 2 h. A hypoxia/restoration (H/R) model was established in buffalo rat liver (BRL) cells by hypoxia for 4 h followed by normoxic conditions for 10 h. The extent of liver injury was assayed by serum ALT/AST, hepatic histology, and MPO activity. Oxidative stress was assayed by serum superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA). Expression of apoptosis-related proteins in BRL cells was assayed in western blots. Expression of AKT and p-AKT proteins in vivo and vitro were assayed in western blots. Results: GA significantly decreased ALT/AST expression, reversed changes in oxidative stress markers induced by I/R, and mediated caspase-3 activity expression of apoptosis-related proteins in vivo and in vitro. Methylthiazol tetrazolium (MTT) assay, flow cytometry, and Hoechst 33258 staining confirmed that GA inhibited apoptosis of BRL cells. GA also increased the expression of phosphorylated AKT after H/R. Conclusion: GA reduced liver I/R injury both in vivo and vitro and inhibited BRL cell apoptosis. PI3K/AKT signaling have been involved. GA may protect against liver I/R and be a potential therapeutic candidate

Reconfigurable Intelligent Surface-Assisted Key Generation for Millimetre-Wave Multi-User Systems

Physical layer key generation (PLKG) leverages wireless channels to produce secret keys for legitimate users. However, in millimetre-wave (mmWave) frequency bands, the presence of blockage significantly reduces the key rate (KR) of a PLKG system. To address this issue, we introduce reconfigurable intelligent surfaces (RISs) as a potential solution for constructing RIS-reflected channels, thereby enhancing the KR. Our study focuses on the beam-domain channel model and exploits the sparsity of mmWave bands to enhance the randomness of secret keys. To relieve pilot overhead in multi-user systems, we employ a compressed sensing (CS) algorithm to estimate angular information and propose a channel probing protocol with the full-array configuration for acquiring the beam-domain channel. We derive the analytical expressions for the KR in the case of full-array configuration. To optimize the KR, we design the phase shift and precoding vectors based on the obtained angular information. Furthermore, we employ a water-filling algorithm that relies on the Karush-Kuhn-Tucker (KKT) conditions to optimize power allocation for estimating the beam-domain channel with the same channel variance. When channel variances of the beam-domain channel differ, we design a deep-learning-based power allocation method for a more complex problem. What is more, we design a sub-array configuration scheme that exploits the difference in spatial angles between users to reduce pilot overhead and derive the analytical expression for the KR. Through extensive simulations, we demonstrate that our proposed PLKG schemes outperform existing methods

Joint Precoding and Phase Shift Design in Reconfigurable Intelligent Surfaces-Assisted Secret Key Generation

Physical layer key generation (PLKG) is a promising technique to establish symmetric keys between resource-constrained legitimate users. However, PLKG suffers from a low key rate in harsh environments where channel randomness is limited. To address the problem, reconfigurable intelligent surfaces (RISs) are introduced to reshape the channels by controlling massive reflecting elements, which can provide more channel diversity. In this paper, we design a channel probing protocol to fully extract the randomness from the cascaded channel, i.e., the channels through reflecting elements. We derive the analytical expressions of the key rate and design a water-filling algorithm based on the Karush-Kuhn-Tucker (KKT) conditions to find the upper bound. To find the optimal precoding and phase shift matrices, we propose an algorithm based on the Grassmann manifold optimization methods. The system is evaluated in terms of the key rate, bit disagreement rate (BDR) and randomness. Simulation results show that our protocols significantly improve the key rate as compared to existing protocols. Compared to multiple-antennas systems without a RIS, our proposed method achieves an average 9.51 dB performance gain when the side length of an element is 1/4 wavelength and the Rician factor is 0 dB

Efficient hole abstraction for highly selective oxidative coupling of methane by Au-sputtered TiO2 photocatalysts

Photocatalytic oxidative coupling of methane (OCM) produces C2 molecules that can be used as building blocks for synthesis of fuels and chemicals. However, the yield rate and the selectivity of C2 products are still moderate due to the stable nature of methane molecules. Here we develop a Au nanocluster-loaded TiO2 photocatalyst by a sputtering approach, achieving a high methane conversion rate of 1.1 mmol h−1, C2 selectivity of ~90% and apparent quantum efficiency of 10.3 ± 0.6%. The high C2/C2+ yield rate is on the same order of magnitude as the benchmark thermal catalysts in OCM processes operated at high temperature (>680 °C). Au nanoparticles are shown to prolong TiO2 photoelectron lifetimes by a factor of 66 for O2 reduction, together with Au acting as a hole acceptor and catalytic centre to promote methane adsorption, C–H activation and C–C coupling. This work underscores the importance of multifunctional co-catalysts and mechanistic understanding to improve photocatalytic OCM

Phosphorus-modified Pt@Cu surfaces for efficient electrocatalysis of hydrogen evolution

Robust and efficient platinum (Pt)-based electrocatalysts are pursued for hydrogen evolution reaction (HER). However, the performance of Pt-based HER electrocatalysts needs to be further improved in alkaline and neutral media due to the extra water dissociation step. Moreover, the fabrication process and long-term stability of current Pt-based HER electrocatalysts are unsatisfactory in mild media. Herein, a one-step facile process was developed to fabricate a phosphorus-modified Pt@Cu (Pt/P@Cu) electrocatalyst to realize the feasibility of high-performance HER in neutral media. The HER performance of Pt/P@Cu is further increased with the successful introduction of phosphorus. P exists as oxides on the Pt/P@Cu surface, which was demonstrated by XPS and Raman. The P doping leads to increased surface active sites, lower charge transfer resistance, and enhanced HER performance in neutral media. Pt/P@Cu presents a low overpotential of 24.3 mV at the current density of −10 mA cm−2, along with an excellent stability reaching −1000 mA cm−2 for 1000 cycles of LSV. The successful P doping on the catalyst surface inspires future study on developing simple surface modifications to increase the electrocatalytic activity to develop advanced electrocatalysts