Video Object Segmentation with Weakly Temporal Information

( Yikun Zhang ),( Rui Yao ),( Qingnan Jiang ),( Changbin Zhang ),( Shi Wang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.3

Video object segmentation is a significant task in computer vision, but its performance is not very satisfactory. A method of video object segmentation using weakly temporal information is presented in this paper. Motivated by the phenomenon in reality that the motion of the object is a continuous and smooth process and the appearance of the object does not change much between adjacent frames in the video sequences, we use a feed-forward architecture with motion estimation to predict the mask of the current frame. We extend an additional mask channel for the previous frame segmentation result. The mask of the previous frame is treated as the input of the expanded channel after processing, and then we extract the temporal feature of the object and fuse it with other feature maps to generate the final mask. In addition, we introduce multi-mask guidance to improve the stability of the model. Moreover, we enhance segmentation performance by further training with the masks already obtained. Experiments show that our method achieves competitive results on DAVIS-2016 on single object segmentation compared to some state-of-the-art algorithms.

Toward Understanding the Differences of PM2.5 Characteristics Among Five China Urban Cities

Zhang Kaiyang,Zhao Chuanfeng,Fan Hao,Yang Yikun,Sun Yue 한국기상학회 2020 Asia-Pacific Journal of Atmospheric Sciences Vol.56 No.4

Characteristics of PM2.5 are investigated and compared based on observations from 2008 to 2017 in Beijing, Shenyang, Shanghai, Chengdu, and Guangzhou, which cover five different climate regions of China. Significant seasonal variations of PM2.5 are found for all five cities, with the largest values in winter and the smallest in summer. The differences of PM2.5 among the five cities are most likely associated with the emission sources, meteorology and topography. The strong emissions with surrounded mountains in Beijing make PM2.5 high, particularly in winter. The basin topography surrounding by mountains in Chengdu makes the pollution hard to disperse and then causes high PM2.5. By contrast, the sea-land breeze helps disperse the air pollution in coastal cities such as Guangzhou and Shanghai by mixing and transport and makes PM2.5 in those cites relatively low. Moreover, the population shows high values in Beijing and Shanghai, and the vehicle amount shows high values in Beijing and Chengdu, contributing to their high PM2.5. Similar monthly variations of PM2.5 are found for the five cities, while the magnitude of variations are different. The five cities demonstrate more different diurnal variations of PM2.5. Associated with the sea-land breeze, there are very weak diurnal variations of PM2.5 in Shanghai and Guangzhou. Differently, significant diurnal variations exist for Beijing, Shengyang and Chengu, with the minimum values in the afternoon and high values at night.

Research on Stress Reduction Model Based on Transformer

Xin Xu,Yikun Zhao,Ruhao Zhang,Tingting Xu 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.12

People are constantly exposed to stress and anxiety environment, which could contribute to a variety of psychological and physical health problems. Therefore, it is particularly important to identify psychological stress in time and to find a feasible and universal method of stress reduction. This research investigated the influence of different music, such as relaxation music and natural rhythm music, on stress relief based on Electroencephalogram signals. Mental arithmetic test was implemented to create a stressful environment. 23 participants performed the mental arithmetic test with and without music respectively, while their Electroencephalogram signal was recorded. The effect of music on stress relief was verified through stress test questionnaires, including Trait Anxiety Inventory (STAI-6) and Self-Stress Assessment. There was a significant change in the stress test questionnaire values with and without music according to paired t-test (p<0.01). Furthermore, a model based on Transformer for stress level classification from Electroencephalogram signal was proposed. Experimental results showed that the method of listening to relaxation music and natural rhythm music achieved the effect of reducing psychological stress and the proposed model yielded a promising accuracy in classifying the Electroencephalogram signal of mental stress.

An improved bearing fault diagnosis method based on variational mode decomposition and adaptive iterative filtering (VMD-AIF)

Lei Fu,Zepeng Ma,Yikun Zhang,Sinian Wang,Libin Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Rolling bearings are widely applied in rotary machines. Bearing failures can lead to long machine downtime and costly maintenance. To reduce the maintenance time and cost, this article proposes a new denoising approach to remove heavy noise and extract weak bearing fault vibration features. The first step proposes a global variational mode decomposition (VMD) optimization algorithm that adaptively matches the optimal decomposition parameters based on kurtosis. In the second step, an adaptive selection criterion for IMF is developed by kurtosis theory. Meanwhile, an adaptive termination criterion is established based on sample entropy (SampEn), and the fault features are extracted with a Butterworth band-pass filter (BBF). Finally, actual fault-bearing experiments are performed using the proposed denoising approach. The comparison with respect to EEMD and WPD is illustrated in detail. The experimental result shows that the proposed approach is a validated tool for the diagnosis of bearings.

Magnetic domain observations of (Tb0.3Dy0.7)Fe1.95 alloys

Li Kuoshe,Fang Yikun,Zhang Shirong,Yu Dunbo,Han Baoshan 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.2

The magnetic domain structures of (Tb0.3Dy0.7)Fe1.95 alloys were investigated using scanning probe atomic and magnetic force microscopies. Results demonstrate that the specimen surface presented corrugated and spiked domain configurations interpreted in terms of surface closure domains in cubic magnetic materials after the specimen was annealed at 673 K for 2 h in an ultra-high vacuum of 5×10−5 Pa. However, a thin soft magnetic Fe layer appeared on the specimen surface after annealing at 723 K for 2 h in a relatively high vacuum of 5×10−3 Pa. As a result, the demagnetized energy in the specimen surface is largely reduced and the interior magnetic domain configurations of the specimen are observed. The results maybe provide an approach for detecting the interior magnetic domain structures of TbDyFe alloys or other cubic magnetic materials.

Numerical and experimental analysis of coupled transverse and longitudinal vibration of a marine propulsion shaft

Qianwen Huang,Xinping Yan,Yikun Wang,Cong Zhang,Yong Jin 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

An appropriate assessment of the dynamic behavior of marine propulsion shaft in ships is essential to enable optional delivery of power to the propeller and to minimize unnecessary vibration. Various vibrations coupling with each other can significantly influence the dynamical behavior of the shaft and threaten the reliability of ships. This paper presents a finite element analysis model with multiple constraint conditions to analyze the coupled transverse and longitudinal vibrations of a marine propulsion shaft. Based on this model, in addition to the coupled natural frequencies of each direction, the maximum acceleration are also determined. Furthermore, the simulation of an idling and loading vibration analysis is discussed and validated against experimental results, over a range of rotational speeds. The output of numerical simulation is found to agree with the corresponding results from experimental tests. Finally, an accurate and applicative FEA model for coupled transverse-longitudinal vibration of shaft has been obtained.