A Cascading Neural Network Ensemble for Locating Faults of Large-scale Information Systems

Chen Zhifeng,Peng Minjing,Li Bo 보안공학연구지원센터 2014 International Journal of Security and Its Applicat Vol.8 No.5

Uncertainty quantification of once-through steam generator for nuclear steam supply system using latin hypercube sampling method

Lekang Chen,Chuqi Chen,Linna Wang,Wenjie Zeng,Zhifeng Li Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

To study the influence of parameter uncertainty in small pressurized water reactor (SPWR) once-through steam generator (OTSG), the nonlinear mathematical model of the SPWR is firstly established. Including the reactor core model, the OTSG model and the pressurizer model. Secondly, a control strategy that both the reactor core coolant average temperature and the secondary-side outlet pressure of the OTSG are constant is adopted. Then, the uncertainty quantification method is established based on Latin hypercube sampling and statistical method. On this basis, the quantitative platform for parameter uncertainty of the OTSG is developed. Finally, taking the uncertainty in primary-side flowrate of the OTSG as an example, the platform application work is carried out under the variable load in SPWR and step disturbance of secondary-side flowrate of the OTSG. The results show that the maximum uncertainty in the critical output parameters is acceptable for SPWR.

An Empirical Study on the Utilization and Performance of the Korea-China FTA in Korean SMEs

Zhifeng Shen,Tae-In Kim,Lifu Chen 한국무역학회 2019 Journal of Korea trade Vol.23 No.4

Purpose - Based on the Korea-China FTA as the starting point, this paper makes an empirical analysis of the main influencing factors of the FTA utilization and performance of SMEs. Design/methodology - Taking into account the relationship between the internal and external environmental factors on FTA activities and performance of Korea’s SMEs, with PLS-SEM and data obtained by the questionnaire, Smart PLS was applied for the analysis. Findings - The recognition of FTA in SMEs has a significant positive effect on FTA utilization and performance, the international marketing orientation factor only has a significant positive effect on the performance, while the inadequate improvement of non-tariff barriers has a significant negative impact on FTA utilization. In addition, FTA activity has a significant mediation effect on two paths. Originality/value - This paper is of great practical relevance as a tool to enable SMEs to make effective utilization of Korea-China FTA and improve their imports and exports. The paper helps grasp the main factors affecting the utilization and performance of FTA for SMEs, also to establish FTA Business Model and FTA utilization plans for specific industries in the future regarding tariff and non-tariffs compatibility.

Design of Type-2 Fuzzy Logic Systems Based on Improved Ant Colony Optimization

Zhifeng Zhang,Tao Wang,Yang Chen,Jie Lan 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

An Improved Ant Colony Optimization (IACO) is proposed to design A2-C1 type fuzzy logic system(FLS) in the paper. The design includes parameters adjustment and rules selection, and the performance of the intelligentfuzzy system, which can be improved by choosing the most optimal parameters and reducing the redundantrules. In order to verify the feasibility of the proposed algorithm, the intelligence fuzzy logic systems based on thealgorithms are applied to predict the Mackey-Glass chaos time series. The simulations show that both the IACO andACO have better tracking performances. The results compared with classical algorithm BP ( back-propagation design)shows the tracking performance of IACO is more precise, the result compared with ACO shows that either thetraining result or the testing result, the tracking performance of IACO is better, and IACO has a faster convergencerate than ACO, the results compared with the Intelligent type-1 fuzzy logic systems show that both the A2-C1 typeFLS based on IACO and ACO have better tracking performance than type-1 fuzzy logic system.

Over expression of a Chitinase 2 gene from Chinese Wild Strawberry improves resistance to anthracnose disease in transgenic Arabidopsis thaliana

Wen Zhifeng,Bai Jinhui,Wang Lin,Yao Liping,Ahmad Bilal,Hanif Muhammad,Chen Qingxi 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.6

Strawberry (Fragaria×ananassa Duch.) is one of the most widely cultivated fruit crop. Anthracnose caused by Colletotrichum spp. is a devastating disease of strawberry, causing large-scale strawberry losses worldwide. Chitinases act as defence proteins and are crucial for plant response to pathogens. Here, we isolated a class V Chitinase gene (designed as FnCHIT2, GenBank accession number MN709779) from Chinese wild diploid strawberry Fragaria nilgerrensis Schlecht (F. nilgerrensis), a species that exhibits high tolerance to anthracnose. Gene expression analysis showed that FnCHIT2 expression was highly induced after Colletotrichum gloeosporiodes inoculation and salicylic acid (SA) treatment. Subcellular localization analysis revealed the presence of FnCHIT2 in the plasma membrane. Recombinant FnCHIT2 protein was successfully expressed in E. coli Rosetta (DE3). Furthermore, we transformed FnCHIT2 into Col-0 wild type A. thaliana to perform functional analysis and evaluated the functions of Colletotrichum higginsianum and Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). FnCHIT2 overexpression in A. thaliana showed enhanced resistance to C. higginsianum and Pst DC3000. Enhanced disease resistance of FnCHIT2 transgenic plants to C. higginsianum was correlated with pathogenesis-related gene 1 (AtPR1) and plant defensin 1.2 (AtPDF1.2) gene expression levels. These results provide evidence that FnCHIT2 may play an important role in response to fungal pathogens in strawberry. Our study provides an important theoretical reference for future strawberry resistance breeding.

An Optimized MPC Method for Restraining the Midpoint Voltage Fluctuation of 3-Level T-Type Grid-Connected Inverter

Dou Zhifeng,Wang Nan,Chen Zhinan,Zheng Anping,Lu Falong,Lv Zhongbin 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

Conventional Finite Control Set Model Predictive Control (FCS-MPC) suffers from large neutral point voltage fluctuation, cumbersome calculation process, as well as high current Total Harmonic Distortions for 3-level T-type grid-tied inverter. An improved FCS-MPC method is proposed in this paper by directly calculating the switch state’s cost function. This method uses the 3-phase switching state Sx to represent the load current i, the DC side neutral point voltage offset ΔUc, the load current prediction value i(k + 1), and establishes a real-time cost function g through 27 switching vectors. In the loop calculation, the switching vector is selected by minimizing the absolute value of the cost function g, and the output switching state is represented by the switching vector. Thus, the inverter can be switched ON or OFF depending on the stat of the next moment. The FCS-MPC of a 3-level T-type grid-tied inverter is also established by simulation, and the effectiveness of the proposed method is verified by experimental results.

The Mixed Kernel Function SVM-based Point Cloud Classification

Chao Chen,Xiaomin Li,Abdelkader Nasreddine Belkacem,Zhifeng Qiao,Enzeng Dong,Wenjun Tan,Duk Shin 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.5

Measurement and detection of ground information by airborne Lidar are one of the hot topics in the field of intelligent sensing in recent years. This study proposes a new point cloud classification algorithm of Mixed Kernel Function SVM to distinguish different types of ground objects. Firstly, the combined features including the coordinate values, the RGB value, normalized elevation, standard deviation of elevation, and elevation difference of point cloud data were extracted. A mixed kernel function of Gauss and Polynomial was designed. Then, one-versus-rest SVM multiple classifiers was constructed. Finally, the feature of 3D point cloud data was employed to train the SVM classifiers. The overall classification accuracies of test data were 97.69% and 99.13% for two data sets, I and II respectively. In addition, the experimental results have showed that the performance of the proposed method with mixed kernel function SVM was better than standard SVM method with Gaussian kernel function and polynomial kernel function only, which demonstrates the effectiveness of the proposed method.

Regional Brain Activity During Rest and Gastric Water Load in Subtypes of Functional Dyspepsia: A Preliminary Brain Functional Magnetic Resonance Imaging Study

Yanwen Chen,Ruifeng Wang,Bo Hou,Feng Feng,Xiucai Fang,Liming Zhu,Xiaohong Sun,Zhifeng Wang,Meiyun Ke 대한소화기 기능성질환∙운동학회 2018 Journal of Neurogastroenterology and Motility (JNM Vol.24 No.2

Background/Aims Functional dyspepsia (FD) remains a great clinical challenge since the FD subtypes, defined by Rome III classification, still have heterogeneous pathogenesis. Previous studies have shown notable differences in visceral sensation processing in the CNS in FD compared to healthy subjects (HS). However, the role of CNS in the pathogenesis of each FD subtype has not been recognized. Methods Twenty-eight FD patients, including 10 epigastric pain syndrome (EPS), 9 postprandial distress syndrome (PDS), and 9 mixed-type, and 10 HS, were enrolled. All subjects underwent a proximal gastric perfusion water load test and the regional brain activities during resting state and water load test were investigated by functional magnetic resonance imaging. Results For regional brain activities during the resting state and water load test, each FD subtype was significantly different from HS (P < 0.05). Focusing on EPS and PDS, the regional brain activities of EPS were stronger than PDS in the left paracentral lobule, right inferior frontal gyrus pars opercularis, postcentral gyrus, precuneus, insula, parahippocampal gyrus, caudate nucleus, and bilateral cingulate cortices at the resting state (P < 0.05), and stronger than PDS in the left inferior temporal and fusiform gyri during the water load test (P < 0.05). Conclusions Compared to HS, FD subtypes had different regional brain activities at rest and during water load test, whereby the differences displayed distinct manifestations for each subtype. Compared to PDS, EPS presented more significant differences from HS at rest, suggesting that the abnormality of central visceral pain processing could be one of the main pathogenesis mechanisms for EPS.

Fast Result Enumeration for Keyword Queries on XML Data

Zhou, Junfeng,Chen, Ziyang,Tang, Xian,Bao, Zhifeng,Ling, TokWang Korean Institute of Information Scientists and Eng 2012 Journal of Computing Science and Engineering Vol.6 No.2

In this paper, we focus on efficient construction of tightest matched subtree (TMSubtree) results, for keyword queries on extensible markup language (XML) data, based on smallest lowest common ancestor (SLCA) semantics. Here, "matched" means that all nodes in a returned subtree satisfy the constraint that the set of distinct keywords of the subtree rooted at each node is not subsumed by that of any of its sibling nodes, while "tightest" means that no two subtrees rooted at two sibling nodes can contain the same set of keywords. Assume that d is the depth of a given TMSubtree, m is the number of keywords of a given query Q. We proved that if d ${\leq}$ m, a matched subtree result has at most 2m! nodes; otherwise, the size of a matched subtree result is bounded by (d - m + 2)m!. Based on this theoretical result, we propose a pipelined algorithm to construct TMSubtree results without rescanning all node labels. Experiments verify the benefits of our algorithm in aiding keyword search over XML data.

Observation of multi-channel non-local transport in J-TEXT plasmas

Shi, Yuejiang,Chen, Zhongyong,Yang, Zhoujun,Shi, Peng,Zhao, Kaijun,Diamond, Patrick H.,Kwon, JaeMin,Yan, Wei,Zhou, Hao,Pan, Xiaoming,Cheng, Zhifeng,Chen, Zhiping,Yang, SeongMoo,Zhang, Chi,Li, Da,Dong, IOP 2018 Nuclear fusion. Fusion nucléaire. &n.Illiga Vol.58 No.4

<P>In cold pulse experiments in J-TEXT, not only are rapid electron temperature increases in the core observed, but also steep rises in the inner density are found. Moreover, some evidence of acceleration of the core toroidal rotation is also observed during the non-local transport process of electron temperature. These new findings of cold pulse experiments in J-TEXT suggest that turbulence spreading is a possible mechanism for the non-local transport dynamics.</P>