An improved YOLOX approach for low-light and small object detection: PPE on tunnel construction sites

Wang Zijian,Cai Zixiang,Wu Yiming 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.3

Tunnel construction sites pose a significant safety risk to workers due to the low-light conditions that can affect visibility and lead to accidents. Therefore, identifying personal protective equipment (PPE) is critical to prevent injuries and fatalities. A few researches have addressed the challenges posed by tunnel construction sites whose light conditions are lower and images are captured from a distance. In this study, we proposed an improved YOLOX approach and a new dataset for detecting low-light and small PPE. We modified the YOLOX architecture by adding ConvNeXt modules to the backbone for deep feature extraction and introducing the fourth YOLOX head for enhancing multiscale prediction. Additionally, we adopted the CLAHE algorithm for augmenting low-light images after comparing it with eight other methods. Consequently, the improved YOLOX approach achieves a mean average precision of 86.94%, which is 4.23% higher than the original model and outperforms selected state-of-the-art. It also improves the average precision of small object classes by 7.17% on average and attains a real-time processing speed of 22 FPS (Frames Per Second). Furthermore, we constructed a novel dataset with 8285 low-light instances and 6814 small ones. The improved YOLOX approach offers accurate and efficient detection performance, which can reduce safety incidents on tunnel construction sites.

Effective time-frequency characterization of Lamb wave dispersion in plate-like structures with non-reflecting boundaries

Wang, Zijian,Qiao, Pizhong,Shi, Binkai Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.2

Research on Lamb wave-based damage identification in plate-like structures depends on precise knowledge of dispersive wave velocity. However, boundary reflections with the same frequency of interest and greater amplitude contaminate direct waves and thus compromise measurement of Lamb wave dispersion in different materials. In this study, non-reflecting boundaries were proposed in both numerical and experimental cases to facilitate time-frequency characterization of Lamb wave dispersion. First, the Lamb wave equations in isotropic and laminated materials were analytically solved. Second, the non-reflecting boundaries were used as a series of frames with gradually increased damping coefficients in finite element models to absorb waves at boundaries while avoiding wave reflections due to abrupt property changes of each frame. Third, damping clay was sealed at plate edges to reduce the boundary reflection in experimental test. Finally, the direct waves were subjected to the slant-stack and short-time Fourier transformations to calculate the dispersion curves of phase and group velocities, respectively. Both the numerical and experimental results suggest that the boundary reflections are effectively alleviated, and the dispersion curves generated by the time-frequency analysis are consistent with the analytical solutions, demonstrating that the combination of non-reflecting boundary and time-frequency analysis is a feasible and reliable scheme for characterizing Lamb wave dispersion in plate-like structures.

Technologies Supporting Hazard Assessment of Chemicals in China

Zijian Wang 환경독성보건학회 2014 한국독성학회 심포지움 및 학술발표회 Vol.2014 No.11

Effective time-frequency characterization of Lamb wave dispersion in plate-like structures with non-reflecting boundaries

Zijian Wang,Pizhong Qiao,Binkai Shi 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.21 No.2

Research on Lamb wave-based damage identification in plate-like structures depends on precise knowledge of dispersive wave velocity. However, boundary reflections with the same frequency of interest and greater amplitude contaminate direct waves and thus compromise measurement of Lamb wave dispersion in different materials. In this study, non-reflecting boundaries were proposed in both numerical and experimental cases to facilitate time-frequency characterization of Lamb wave dispersion. First, the Lamb wave equations in isotropic and laminated materials were analytically solved. Second, the non-reflecting boundaries were used as a series of frames with gradually increased damping coefficients in finite element models to absorb waves at boundaries while avoiding wave reflections due to abrupt property changes of each frame. Third, damping clay was sealed at plate edges to reduce the boundary reflection in experimental test. Finally, the direct waves were subjected to the slant-stack and short-time Fourier transformations to calculate the dispersion curves of phase and group velocities, respectively. Both the numerical and experimental results suggest that the boundary reflections are effectively alleviated, and the dispersion curves generated by the time-frequency analysis are consistent with the analytical solutions, demonstrating that the combination of non-reflecting boundary and time-frequency analysis is a feasible and reliable scheme for characterizing Lamb wave dispersion in plate-like structures.

A comprehensive study on active Lamb wave-based damage identification for plate-type structures

Zijian Wang,Pizhong Qiao,Binkai Shi 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.6

Wear and aging associated damage is a severe problem for safety and maintenance of engineering structures. To acquire structural operational state and provide warning about different types of damage, research on damage identification has gained increasing popularity in recent years. Among various damage identification methods, the Lamb wave-based methods have shown promising suitability and potential for damage identification of plate-type structures. In this paper, a comprehensive study was presented to elaborate four remarkable aspects regarding the Lamb wave-based damage identification method for plate-type structures, including wave velocity, signal denoising, image reconstruction, and sensor layout. Conclusions and path forward were summarized and classified serving as a starting point for research and application in this area.

Energy-Efficient Traffic Grooming in Bandwidth Constrained IP over WDM Networks

( Bin Chen ),( Zijian Yang ),( Rongping Lin ),( Mingjun Dai ),( Xiaohui Lin ),( Gongchao Su ),( Hui Wang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.6

Minimizing power consumption in bandwidth limited optical traffic grooming networks is presented as a two-objective optimization problem. Since the main objective is to route a connection, the network throughput is maximized first, and then the minimum power consumption solution is found for this maximized throughput. Both transparent IP over WDM (Tp-IPoWDM) and translucent IP over WDM (Tl-IPoWDM) network may be applied to examine such bi-objective algorithms. Simulations show that the bi-objective algorithms are more energy-efficient than the single objective algorithms where only the throughput is optimized. For a Tp-IPoWDM network, both link based ILP (LB-ILP) and path based ILP (PB-ILP) methods are formulated and solved. Simulation results show that PB-ILP can save more power than LB-ILP because PB-ILP has more path selections when lightpath lengths are limited. For a Tl-IPoWDM network, only PB-ILP is formulated and we show that the Tl-IPoWDM network consumes less energy than the Tp-IPoWDM network, especially under a sparse network topology. For both kinds of networks, it is shown that network energy efficiency can be improved by over-provisioning wavelengths, which gives the network more path choices.

Concrete strength monitoring based on the variation of ultrasonic waveform acquired by piezoelectric aggregates

Li Wei,Zijian Wang,Maosen Cao,Ronghua Fu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.5

Ultrasonic waves provide a non-destructive and sensitive way to monitor the concrete hydration. However, limited works are reported to monitor the evolution of the mechanical parameter at early ages. In this study, modified piezoelectric aggregates are embedded inside a concrete beam to excite and receive primary waves. A hydration index, namely, the variation of ultrasonic waveform (VUW) is developed to characterize the variation of the transmitted waves during the hydration process. The recorded hydration indices are compared with the compressive strength measured by destructive test at different ages. The results show that the VUW is closer to the compressive strength than the other two traditional hydration indices, ultrasonic velocity and wave packet energy. The proposed VUW provides a simple and accurate way to monitor the concrete hydration at early ages.

Optimization of Powder Impregnation Process Parameters of Carbon Fiber Reinforced Polyether-ether-ketone Prepreg Tape by Response Surface Methodology

Tianyun Wan,Huihuang Ma,Zijian Wang,Chuanjie Fan,Xiaodong Zhou 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

Carbon fiber reinforced polyether-ether-ketone (CF/PEEK) composite materials had a wide range of applicationsin the aerospace, electronics and electrical fields, etc. The composite materials were generally prepared from prepregs. Commonly used prepreg tape preparation methods had disadvantages of uneven resin distribution and inadequate fiberimpregnation, resulting in high porosity and poor mechanical properties. In this research, a combined process of the doublepowder impregnation method and the melt homogenization method was used to prepare the CF/PEEK prepreg tape to solvethe previous problems. Using this method, the porosity of the prepreg tape was reduced by 56.30 % and the tensile strengthwas increased by 43.35 % compared with the traditional powder impregnation method. At the same time, the prepreg tapewas widened and thinned and the uniformity of resin distribution was improved. Besides, based on the single factorexperiment, the response surface method was used to construct the impregnation model of the quadratic polynomialregression equation between the process parameters (powder impregnation temperature, traction speed and melthomogenization temperature) and the porosity of the CF/PEEK prepreg tape. According to this model, the process parametersfor the porosity of the prepreg tape were calculated to reach the minimum, namely, the powder impregnation temperature was380 ℃, the traction speed was 1 m/min, and the melt homogenization temperature was 380 ℃. As a result of these processparameters, the porosity of the prepreg tape could be reduced to 7.39 %. Subsequently, the model was verified throughexperiments, which could provide a reference for the process parameters setting of the impregnation process.

A Survey of Remote Data Integrity Checking: Techniques and Verification Structures

Yu Chen,Feng Wang,Liehuang Zhu,Zijian Zhang 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.4

Cloud storage offers clients great convenience to relieve them from heavy burden of storage and management, so an increasing number of clients choose to outsource their data to remote cloud providers. However, for clients, this entails a sacrifice of actual control of these files. Remote servers may suffer from disk failure for uncertain reasons or even delete rarely accessed data to sell these storages to other clients. Therefore, there’s a great necessity for clients to make sure that their data are well stored in remote servers. Numbers of remote integrity checking (RIC) schemes are proposed to solve issues above, including following up work Provable Data Possession (PDP) and Proofs of Retrievability (PoR), which can be applied in cloud auditing. This paper presents state-of-the-art RIC schemes and makes a classification from the perspective of whether they support dynamic verifications, i.e., whether they can still be used to make verifications after clients modify, insert or delete files. In static verification schemes, we delve into the mechanisms and techniques used for integrity checking. For dynamic ones, we discuss the authentication structures that support dynamic operations. We also present several remarks to guide readers to a wide vision of data checking as conclusions and future work.

Human Intersectin 2 (ITSN2) binds to Eps8 protein and enhances its degradation

( Xiao Feng Ding ),( Zijian Yang ),( Fang Liang Zhou ),( Xiang Huchang ),( Zhou Chang Luo ),( Zhi Cheng He ),( Qian Liu ),( Hong Li ),( Feng Yan ),( Fang Mei Wang ),( Shuang Lin Xiang ),( Jian Zhang ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2012 BMB Reports Vol.45 No.3

Participates in actin remodeling through Rac and receptor endocytosis via Rab5. Here, we used yeast two-hybrid system with Eps8 as bait to screen a human brain cDNA library. ITSN2 was identified as the novel binding factor of Eps8. The interaction between ITSN2 and Eps8 was demonstrated by the in vivo co-immunoprecipitation and colocalization assays and the in vitro GST pull-down assays. Furthermore, we mapped the interaction domains to the region between amino acids 260-306 of Eps8 and the coiled-coil domain of ITSN2. In addition, protein stability assays and immunofluorescence analysis showed ITSN2 overexpression induced the degradation of Eps8 proteins, which was markedly alleviated with the lysosome inhibitor NH4Cl treatment. Taken together, our results suggested ITSN2 interacts with Eps8 and stimulates the degradation of Eps8 proteins. [BMB reports 2012; 45(3): 183-188]