Online Hop Timing Detection and Frequency Estimation of Multiple FH Signals

Zhi-Chao Sha,Zhang-Meng Liu,Zhi-Tao Huang,Yi-Yu Zhou 한국전자통신연구원 2013 ETRI Journal Vol.35 No.5

This paper addresses the problem of online hop timing detection and frequency estimation of multiple frequencyhopping (FH) signals with antenna arrays. The problem is deemed as a dynamic one, as no information about the hop timing, pattern, or rate is known in advance, and the hop rate may change during the observation time. The technique of particle filtering is introduced to solve this dynamic problem, and real-time frequency and direction of arrival estimates of the FH signals can be obtained directly, while the hop timing is detected online according to the temporal autoregressive moving average process. The problem of network sorting is also addressed in this paper. Numerical examples are carried out to show the performance of the proposed method.

Synthesis and Evaluation O-Benzyl Oxime-ether Derivatives Containing β-Methoxyacrylate Moiety for Insecticidal and Fungicidal Activities

Zhi-Bin Hu,He-An Luo,Xiao-Guang Wang,Ming-Zhi Huang,Lu Huang,Huai-Lin Pang,Chun-Hui Mao,Hui Pei,Chao-Qun Huang,Jiong Sun,Ping-Le Liu,Ai-Ping Liu 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

In attempt to lead compounds exhibiting both insecticidal and fungicidal activities, a series of O-benzyl oximeether derivatives were designed and synthesized by introducing β-methoxyacrylate pharmacophore into a scaffold. The insecticidal activity against Aphis fabae and the fungicidal activity against Erysiphe graminis were screened. The title compounds exhibited remarkable insecticidal and fungicidal activities. The most potent compound 6d was identified. Its insecticidal LC50 against A. fabae is 6.4 mg/L, which is lower than that of chlorfenapyr (19.4 mg/L) and even close to the level of imidacloprid (4.8 mg/L). Its fungicidal EC90 in preventive and curative treatment against E. graminis are 2.2 and 4.8 mg/L, respectively, which are lower than azoxystrobin (7.0 and 5.9 mg/L). These results indicate that compound 6d can be considered as a lead for further developing new O-benzyl oxime-ether typed candidates with both fungicidal and insecticidal activities.

Hybrid machine learning with mode shape assessment for damage identification of plates

Zhi Chao Ong,Pei Yi Siow,Shin Yee Khoo,Kok-Sing Lim,Bee Teng Chew 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.31 No.5

Machine learning-based structural health monitoring (ML-based SHM) methods are researched extensively in the recent decade due to the availability of advanced information and sensing technology. ML methods are well-known for their pattern recognition capability for complex problems. However, the main obstacle of ML-based SHM is that it often requires precollected historical data for model training. In most actual scenarios, damage presence can be detected using the unsupervised learning method through anomaly detection, but to further identify the damage types would require prior knowledge or historical events as references. This creates the cold-start problem, especially for new and unobserved structures. Modal-based methods identify damages based on the changes in the structural global properties but often require dense measurements for accurate results. Therefore, a two-stage hybrid modal-machine learning damage detection scheme is proposed. The first stage detects damage presence using Principal Component Analysis-Frequency Response Function (PCA-FRF) in an unsupervised manner, whereas the second stage further identifies the damage. To solve the cold-start problem, mode shape assessment using the first mode is initiated when no trained model is available yet in the second stage. The damage identified by the modal-based method would be stored for future training. This work highlights the performance of the scheme in alleviating the cold-start issue as it transitions through different phases, starting from zero damage sample available. Results showed that single and multiple damages can be identified at an acceptable accuracy level even when training samples are limited.

Vision-Based Defect Detection for Mobile Phone Cover Glass using Deep Neural Networks

Zhi-Chao Yuan,Zheng-Tao Zhang,Hu Su,Lei Zhang,Fei Shen,Feng Zhang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.6

The emergency of surface defect would significantly influence the quality of MPCG (Mobile Phone Cover Glass). Therefore, efficient defect detection is highly required in the manufacturing process. Focusing on the problem, an automatic detection system is developed in this paper. The system adopts backlight imaging technology to improve the signal to noise ration and imaging effect. Then, a modified segmentation method is presented for defect extraction and measurement based on deep neural networks. In the method, a novel data generation process is provided, with which the drawback that huge amount of data is required for training deep structured networks can be overcome. Finally, experiments are well conducted to verify that satisfactory performance is achieved with the proposed method.

An experimental investigation on the effects of exponential window and impact force level on harmonic reduction in impact-synchronous modal analysis

Ong Zhi Chao,Lim Hong Cheet,Khoo Shin Yee,Abdul Ghaffar Abdul Rahman,Zubaidah Ismail 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

A novel method called Impact-synchronous modal analysis (ISMA) was proposed previously which allows modal testing to be performed during operation. This technique focuses on signal processing of the upstream data to provide cleaner Frequency response function (FRF) estimation prior to modal extraction. Two important parameters, i.e., windowing function and impact force level were identified and their effect on the effectiveness of this technique were experimentally investigated. When performing modal testing during running condition, the cyclic loads signals are dominant in the measured response for the entire time history. Exponential window is effectively in minimizing leakage and attenuating signals of non-synchronous running speed, its harmonics and noises to zero at the end of each time record window block. Besides, with the information of the calculated cyclic force, suitable amount of impact force to be applied on the system could be decided prior to performing ISMA. Maximum allowable impact force could be determined from nonlinearity test using coherence function. By applying higher impact forces than the cyclic loads along with an ideal decay rate in ISMA, harmonic reduction is significantly achieved in FRF estimation. Subsequently, the dynamic characteristics of the system are successfully extracted from a cleaner FRF and the results obtained are comparable with Experimental modal analysis (EMA).

A Study on C2B2C Business Integration Model Design Focusing On the Fashion Clothes Business

Cheng, Zhi-Chao,Kwon, Donghwoon,Jin, Chang-Hai,Kwon, YoungJik Korea Multimedia Society 2016 The journal of multimedia information system Vol.3 No.3

We firstly tried to understand consumers' purchasing tendencies and mainly focused on designing a platform model that offers integrated support. C2B (Customer to Business) orders integrate with a consumption platform of a B2C (Business to Customer) model, and integrated support aims at design, supply, processing, and distribution of a fashion business. All the information such as orders, sales, production, supply, and settlement of accounts is synchronized under the C2B, B2C, and O2O (Online to Offline) environment so that accurate information can be shared in real time. Our platform automatically handles with a net income of a product designer, manufacturer, and shipping company once shipping is confirmed.

Computational modeling of buried blast-induced ground motion and ground subsidence

Zhang, Zhi-Chao,Liu, Han-Long,Pak, Ronald Y.S.,Chen, Yu-Min Techno-Press 2014 Geomechanics & engineering Vol.7 No.6

To complement the method of field-scale seismic ground motion simulations by buried blast techniques, the application and evaluation of the capability of a numerical modeling platform to simulate buried explosion-induced ground motion at a real soil site is presented in this paper. Upon a layout of the experimental setup at a level site wherein multiple charges that were buried over a large-diameter circle and detonated in a planned sequence, the formulation of a numerical model of the soil and the explosives using the finite element code LS-DYNA is developed for the evaluation of the resulting ground motion and surface subsidence. With a compact elastoplastic cap model calibrated for the loess soils on the basis of the site and laboratory test program, numerical solutions are obtained by explicit time integration for various dynamic aspects and their relation with the field blast experiment. Quantitative comparison of the computed ground acceleration time histories at different locations and induced spatial subsidence on the surface afterwards is given for further engineering insights in regard to the capabilities and limitations of both the numerical and experimental approaches.

Evaluation of insecticidal activity of the essential oil of Allium chinense G. Don and its major constituents against Liposcelis bostrychophila Badonnel

Xin Chao Liu,Xiao Nan Lu,Qi Zhi Liu,Zhi Long Liu 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.4

Water-distilled essential oil from the dried bulbs of Allium chinense (Liliaceae) was analyzed by gaschromatography–mass spectrometry (GC–MS). Eighteen compounds, accounting for 98.4% of the total oil,were identified and the main components of the essential oil of A. chinense were methyl allyl trisulfide(30.7%), dimethyl trisulfide (24.1%), methyl propyl disulfide (12.8%) and dimethyl disulfide (9.6%) followed bymethyl allyl disulfide (3.4%) and methyl propyl trisulfide (3.6%). The essential oil exhibited contact toxicityagainst the booklice (Liposcelis bostrychophila) with an LC50 value of 441.8 μg/cm2 while the two major constituents,dimethyl trisulfide and methyl propyl disulfide had LC50 values of 153.0 μg/cm2 and 738.0 μg/cm2 againstthe booklice, respectively. The essential oil of A. chinense possessed strong fumigant toxicity against the booklicewith an LC50 value of 186.5 μg/l while methyl allyl trisulfide (LC50=90.4 μg/l) and dimethyl trisulfide (LC50=114.2 μg/l) exhibited stronger fumigant toxicity than methyl propyl disulfide (LC50= 243.4 μg/l) and dimethyldisulfide (LC50= 340.8 μg/l) against the booklice. The results indicated that the essential oil and itsmajor constituentshave potential for development into natural insecticides or fumigants for control of insects in stored grains.

Synthesis and Evaluation O-Benzyl Oxime-ether Derivatives Containing β-Methoxyacrylate Moiety for Insecticidal and Fungicidal Activities

Hu, Zhi-Bin,Luo, He-An,Wang, Xiao-Guang,Huang, Ming-Zhi,Huang, Lu,Pang, Huai-Lin,Mao, Chun-Hui,Pei, Hui,Huang, Chao-Qun,Sun, Jiong,Liu, Ping-Le,Liu, Ai-Ping Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

In attempt to lead compounds exhibiting both insecticidal and fungicidal activities, a series of O-benzyl oximeether derivatives were designed and synthesized by introducing ${\beta}$-methoxyacrylate pharmacophore into a scaffold. The insecticidal activity against Aphis fabae and the fungicidal activity against Erysiphe graminis were screened. The title compounds exhibited remarkable insecticidal and fungicidal activities. The most potent compound 6d was identified. Its insecticidal $LC_{50}$ against A. fabae is 6.4 mg/L, which is lower than that of chlorfenapyr (19.4 mg/L) and even close to the level of imidacloprid (4.8 mg/L). Its fungicidal $EC_{90}$ in preventive and curative treatment against E. graminis are 2.2 and 4.8 mg/L, respectively, which are lower than azoxystrobin (7.0 and 5.9 mg/L). These results indicate that compound 6d can be considered as a lead for further developing new O-benzyl oxime-ether typed candidates with both fungicidal and insecticidal activities.

플랫폼기반 ERP<SUP>+</SUP> 시스템 설계에 관한 연구

승지초(Zhi-Chao Cheng),김창해(Chang-Hai Jin),권영직(Young-Jik Kwon) 한국데이타베이스학회 2015 Journal of information technology applications & m Vol.22 No.4

In this paper, we designed a platform-based ERP<SUP>+</SUP> system, which integrates ERP system and SCM system. With platform-based technology we can connect online and offline platforms, enterprise management systems, and government systems. In our research, first we examined the problems of the existing ERP systems, and second we discussed all basic tasks of our ERP<SUP>+</SUP> system. We also designed several modules for this platform-based system and system network. Our results showed that a platform-based ERP<SUP>+</SUP> system can effectively manage the information and the human/material resources, by using O2O (online to offline) technic. Even different systems can be integrated effectively. It can reduce the costs of enterprise management activities, enhance the enterprise competitiveness.