Twin Minimax Probability Machine for Handwritten Digit Recognition

Zhijie Xu,Jianqin Zhang,Hengyou Wang 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.2

Handwritten digit recognition is a task of great importance in many applications. There are different challenges faced while attempting to solve this problem. It has drawn much attention from the field of machine learning and pattern recognition. Minimax probability machine (MPM) is a novel method in machine learning and data mining. In this paper, we present an extension algorithm for MPM, which is named twin minimax probability machine (TWMPM). TWMPM generates two hyperplanes to improve the classification accuracy. Experiment results on several data sets from the UCI repository demonstrate that TWMPM can improve performance of MPM in most cases. The proposed method is used for recognizing the handwritten digits provided in the MNIST data set of images of handwritten digits (0-9). The testing accuracies are improved comparing with MPM.

Discrete Element Study on Mesoscopic Shear Mechanical Behavior of Fully Weathered Coastal Red Sandstone Considering Different Rock Mass Stability Grades

Zhijie Wang,Xiaohao Rui,Haiyan Xu,Mingfan Zhao,Zhihong Qiu,Zengzhao Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

The macro parameters such as cohesion and internal friction angle are usually measured on experimental test. The macro shear mechanical behaviors are determined by mesoscopic shear mechanical behaviors, which are difficult to be measured accurately on experimental test. This paper aims to study the mesoscopic shear mechanical behaviors of fully weathered coastal red sandstone (FWCRS) such as the force and displacement of rock particles, the force chain network, the microcracks and the coordination number, which can be systematically studied by discrete element software such as Particle Flow Code (PFC). This paper established models characterizing FWCRS with different rock mass stability grades by results obtained on experimental tests, and investigated the differences of their mesoscopic shear mechanical behaviors. The results show that the mesoscopic shear mechanical behaviors of FWCRS can be characterized by performing direct shear simulation and the differences among different rock mass stability grades were also revealed. As the stability increases from grade 1 to grade 5, the shear stiffness increases, the number of microcracks reduces by 48.07%, and there are significant differences in properties of shear band, development of microcrack, the coordination number and the force chain network. The research results can provide reference for the related research such as the evolution of mesoscopic shear mechanical behaviors in the failure process of rock mass in FWCRS and similar strata.

Ultrathin Metamaterial for Polarization Independent Perfect Absorption and Band-pass Filter

Xu Zhang,Zhijie Gong 한국광학회 2015 Current Optics and Photonics Vol.19 No.6

We demonstrate an ultrathin metamaterial for polarization independent perfect absorption as well as aband-pass filter (BPF) which works at a higher frequency band compared to the perfect absorption band. The planar metamaterial is comprised of three layers, symmetric split ring resonators (SSRRs) at the frontand structured ground plane (SGP) at the back separated by a dielectric layer. The perfect metamaterialabsorber (MA) can realize near 100% absorption due to high electromagnetic losses from the electric and/ormagnetic resonances within a certain frequency band. The thickness of the structure is only 1/28 of themaximum absorption wavelength

Sub-level Classification and Prediction System of Fully Weathered Red Sandstone Rock Mass Based on Physical Property Indices

Haiyan Xu,Zimeng Shao,Zhijie Wang,Libin Cai,Zhen Li,Xinzheng Jiang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

This paper intends to obtain a sub-level classification of fully weathered red sandstone rock mass during the Cretaceous period based on physical property indices. An automatic prediction system for mechanical properties of rock mass is also established in which the values of rock mass grade and mechanical properties can be returned when physical indices are given. In this study, water content, relative compaction, and fine content, which are relatively easy to measure on tunnel sites, are selected as physical property indices, while cohesion, internal friction angle, and compression modulus, which affect mechanical strength, are taken as mechanical indices. For the convenience of analysis, rock mass of different physical states is divided into 18 different combinations based on the results of lab tests and rock mass stability of each state is evaluated using a stability evaluation criterion we put forward. The numerical simulation of tunnel excavation is further carried out for determining the sub-level classification. A decision tree model is applied for further studying the relationship between physical and mechanical indices to ensure accurate prediction. The result shows that the prediction system works with high accuracy and can be used for engineering reference for fully weathered red sandstone rock mass.

Multifunctional nanozyme‑reinforced copper‑coordination polymer nanoparticles for drug‑resistance bacteria extinction and diabetic wound healing

Jiahui Zhao,Tengfei Xu,Jichao Sun,Haitao Yuan,Mengyun Hou,Zhijie Li,Jigang Wang,Zhen Liang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Drug-resistant bacterial infections in chronic wounds are a persistent issue, as they are resistant to antibiotics and can cause excessive inflammation due to generation of reactive oxygen species (ROS). An effective solution would be to not only combat bacterial infections but also scavenge ROS to relieve inflammation at the wound site. Scaffolds with antioxidant properties are attractive for their ability to scavenge ROS, and there is medical demand in developing antioxidant enzyme-mimicking nanomaterials for wound healing. Methods In this study, we fabricated copper-coordination polymer nanoparticles (Cu-CPNs) through a self-assembly process. Furthermore, ε-polylysine (EPL), an antibacterial and cationic polymer, was integrated into the Cu-CPNs structure through a simple one-pot self-assembly process without sacrificing the glutathione peroxidase (GPx) and superoxide dismutase (SOD)-mimicking activity of Cu-CPNs. Results The resulting Cu-CPNs exhibit excellent antioxidant propertiesin mimicking the activity of glutathione peroxidase and superoxide dismutase and allowing them to effectively scavenge harmful ROS produced in wound sites. The in vitro experiments showed that the resulting Cu-CPNs@EPL complex have superior antioxidant properties and antibacterial effects. Bacterial metabolic analysis revealed that the complex mainly affects the cell membrane integrity and nucleic acid synthesis that leads to bacterial death. Conclusions The Cu-CPNs@EPL complex has impressive antioxidant properties and antibacterial effects, making it a promising solution for treating drug-resistant bacterial infections in chronic wounds. The complex’s ability to neutralize multiple ROS and reduce ROS-induced inflammation can help relieve inflammation at the wound site.

Current progress on gold recovery from refractory ore and waste electrical and electronic equipment

Ji Xuran,Shen Zhijie,Xu Wenping,Yao Shimiao,Zhang Hairong,Xiong Lian,Li Hailong,Guo Haijun,Chen Xuefang,Chen Xinde 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

The physical and chemical properties of gold promote its application, such as in the high-tech, electronic products, and aerospace industries. The easily leachable ore is gradually depleted. Thus, it becomes necessary to extract gold from other resources such as refractory ore and electrical and electronic equipment. The normal method of leaching for gold is cyanide leaching, but it is very dangerous for both environment and operator. Non-cyanide leaching methods, including thiourea leaching, halide leaching, and sulfate leaching have been developed to substitute cyanide leaching. A variety of methods to enrich gold from leaching solutions are described in this paper, including solvent extraction, electrowinning, activated carbon adsorption, and ion exchange resins. Among those methods, ion exchange resins can adsorb gold with high adsorption efficiency and regenerate easily as well. This paper focuses on the research progress of the recovery of gold from non-cyanide leachates by ion exchange resins, summarizes the existing resin types and elution processes, points out the limitations in the application of current ion exchange resins, and discusses possible solutions.

Analytical Solution for Interaction between Tunnel Surrounding Rock and Supports in Red Sandstone Stratum

Zhen Li,Haiyan Xu,Zhijie Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

Improving the flexibility of the support system is an effective measure to prevent structural failure caused by large deformation of the surrounding rock in tunnels passing through red sandstone stratum. By utilizing the staged support installation method, the initial install location of the supports can be adjusted to control the flexibility of the support system. However, there is currently no corresponding analytical solution available to accurately predict the mechanical behavior of the surrounding rock and supports. This paper proposes an analytical solution for the whole process of interaction between the surrounding rock and supports. Firstly, based on the improved unified strength criterion and non-associated flow rule, an elastoplastic analysis of the surrounding rock of a circular tunnel in red sandstone stratum is conducted, which takes into account intermediate principal stress, dilatancy, and nonlinear strain-softening properties. Next, six types of interaction between the surrounding rock and supports are proposed, along with corresponding judge theorems. Furthermore, an analytical solution for the mechanical response of the surrounding rock and supports during the whole construction process are presented. After verifying its effectiveness, a parametric analysis is performed to investigate the influence of design parameters on the supporting effect. Finally, the application effect of the staged support installation method is compared with that of the traditional method, and the cost savings advantage of the former is demonstrated.

Optimization and simulation of the operational motion of a pantograph: Uplift and retraction

Fang Jia,Fengyu Xu,Hang Zhou,Defeng Zhang,Zhijie Xia 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

A single-arm pantograph of metro train was studied in this work. The mathematical model of a single-arm pantograph was first established and an optimal design method to obtain the geometric parameters of the pantograph was proposed. The 3D model for the pantograph was then built and the simulation was performed by using virtual prototyping technology to ensure superior performance of the optimized pantograph. The fatigue test of pantograph-insulator system was performed under two operating conditions: Electric pantograph lifting and real train operation. Fatigue test results validated the stability of the optimized pantograph system.

Fatigue properties of the pantograph–insulator system of metro trains: Experiments and the design for improvement

Fang Jia,Fengyu Xu,Zhijie Xia,Hang Zhou,Defeng Zhang 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

The power of a metro vehicle is supplied by the pantograph on the vehicle roof. During pantograph lifting, the insulator set of the pantograph is prone to fracture caused by the impact load. In this work, a Single-arm pantograph–insulator system (SPIS) of metro vehicles was studied for the fatigue fracture of the insulator set induced by impact load. The basic structure of the SPIS was first introduced. The dynamic axial force test and fatigue and fracture damage experiments was then conducted on SPIS for both simulation experiment platform and real vehicles to analyze the causes of the insulator fracture. A method to improve the design structure of the back-end insulator set was proposed to resolve the problems of both the impact failure of the insulator steel core and the stress concentration on the interface between a steel core and an epoxy resin. The finite element analysis results indicated that the improved insulator set shows a much smaller stress concentration. Therefore, the improved insulator set has a greatly reduced fatigue damage subjected to shear effect, which validated the feasibility of the improved structure design.

Beyond Canonical PROTAC: Biological targeted protein degradation (bioTPD)

Huifang Wang,Runhua Zhou,Fushan Xu,Kongjun Yang,Liuhai Zheng,Pan Zhao,Guangwei Shi,Lingyun Dai,Chengchao Xu,Le Yu,Zhijie Li,Jianhong Wang,Jigang Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Targeted protein degradation (TPD) is an emerging therapeutic strategy with the potential to modulate disease associated proteins that have previously been considered undruggable, by employing the host destructionmachinery. The exploration and discovery of cellular degradation pathways, including but not limited toproteasomes and lysosome pathways as well as their degraders, is an area of active research. Since the conceptof proteolysis-targeting chimeras (PROTACs) was introduced in 2001, the paradigm of TPD has been greatlyexpanded and moved from academia to industry for clinical translation, with small-molecule TPD being particularlyrepresented. As an indispensable part of TPD, biological TPD (bioTPD) technologies including peptide-, fusionprotein-, antibody-, nucleic acid-based bioTPD and others have also emerged and undergone significantadvancement in recent years, demonstrating unique and promising activities beyond those of conventional small molecule TPD. In this review, we provide an overview of recent advances in bioTPD technologies, summarize theircompositional features and potential applications, and briefly discuss their drawbacks. Moreover, we present somestrategies to improve the delivery efficacy of bioTPD, addressing their challenges in further clinical development.