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A FINITE DIFFERENCE/FINITE VOLUME METHOD FOR SOLVING THE FRACTIONAL DIFFUSION WAVE EQUATION
Sun, Yinan,Zhang, Tie Korean Mathematical Society 2021 대한수학회지 Vol.58 No.3
In this paper, we present and analyze a fully discrete numerical method for solving the time-fractional diffusion wave equation: ∂<sup>β</sup><sub>t</sub>u - div(a∇u) = f, 1 < β < 2. We first construct a difference formula to approximate ∂<sup>β</sup><sub>t</sub>u by using an interpolation of derivative type. The truncation error of this formula is of O(△t<sup>2+δ-β</sup>)-order if function u(t) ∈ C<sup>2,δ</sup>[0, T] where 0 ≤ δ ≤ 1 is the Hölder continuity index. This error order can come up to O(△t<sup>3-β</sup>) if u(t) ∈ C<sup>3</sup> [0, T]. Then, in combinination with the linear finite volume discretization on spatial domain, we give a fully discrete scheme for the fractional wave equation. We prove that the fully discrete scheme is unconditionally stable and the discrete solution admits the optimal error estimates in the H<sup>1</sup>-norm and L<sub>2</sub>-norm, respectively. Numerical examples are provided to verify the effectiveness of the proposed numerical method.
The Molecular Characterization of Serogroup C Neisseria meningitidis Strains Circulating in Beijing
Tie-gang Zhang,Jing-guo He,Xiong He,Li-Juan Chen,Zhu-jun Shao,Mei-ping Sun 한국미생물학회 2006 The journal of microbiology Vol.44 No.6
The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.
Laboratory Confirmation of A Suspicious Meningococcal Meningitis Death Case
Tie-gang Zhang,Li-juan Chen,Jie Yang,Zhu-jun Shao,Xiong He,Jing-guo He,Ming Luo,Mei-ping Sun 한국미생물학회 2006 The journal of microbiology Vol.44 No.4
A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.
Wei Sun,Tie-qiang MA,Yu-jun Huang 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.1
Data exchange between heterogeneous CAD systems is the key problem in the field of CAD, and the popular solution to this problem is a feature-based method. Aiming at keeping the consistency of design intent in data exchange between heterogeneous CAD systems, this research focuses on the method of constraint conversion. First, two kinds of basic feature transformation ways are summarized, and this is the foundation of constraint conversion. Second, a novel identification of geometric elements based on the improved geometric certificate is proposed, and the identifier of geometric element is used to recognize the acting object of constraint. Third, the principles of constraint conversion are put forward, and the method of constraint conversion for a single feature is proposed according to the principles. Fourth, an algorithm of constraint conversion for the whole process of CAD data exchange is designed. Finally, the contrast experiment of CAD data exchange is completed, and the result of the experiment shows that the approach mentioned above is effective.
The Molecular Characterization of Serogroup C Neisseria meningitidis Strains Circulating in Beijing
Zhang, Tie-Gang,He, Jing-Guo,He, Xiong,Chen, Li-Juan,Shao, Zhu-Jun,Sun, Mei-Ping The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.6
The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.
Laboratory Confirmation of A Suspicious Meningococcal Meningitis Death Case
Zhang Tie-Gang,He Xiong,Chen Li-Juan,He Jing-Guo,Luo Ming,Yang Jie,Shao Zhu-Jun,Sun Mei-Ping The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.4
A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.
Study on Property of Diamond Mobile Telephone Windows
Liu Tie-Lin,Yang Guang-Sheng,Zhou Jian-Wu,Sun Yi-Ning 한국진공학회(ASCT) 2002 Journal of Korean Vacuum Science & Technology Vol.6 No.2
a-C:H films were coated on windows of mobile telephone by RF plasma chemical vapor deposition equipment made in our company. Thickness of the coatings is about 0.7 micrometers and they have high hardness, low friction coefficient, good adhesion, high optical transparency and chemical inertness. Knoop hardness of the diamond-like carbon films on glass substrate is 2328 ㎏/㎣. The adherence between films and substrate is good and shows to be 69 N by scratching test. The optical performance is improved obviously owing to coat the film on it. The index of the coated windows is 2.5, transmission of visible light is larger than 90%, and transmission of ultraviolet light decreases by 30% and the ultraviolet light can be obstructed obviously. The coated glass also has self-clean effect and decontamination ability. The films have hydrophobic character and the soakage angle of water drop is larger than 90 degrees. The windows have fog-proof ability owing to eliminate the capillary phenomena in the inner surface. The physics and chemical properties of the coated windows are steady. Study indicates that the performance of a-C:H coated mobile phone windows are improved notably on wear-resistance, corrosion-proof and optical properties and it is excellent mobile windows protective coatings.
Research on Recognition Method of Electrical Components Based on FEYOLOv4-tiny
Gao Jilong,Sun Haoran,Han Jiarui,Sun Qian,Zhong Tie 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.6
Recently, electrical component recognition technology is of great signifi cance for fault identifi cation and stable operation of the modern power grids. With the rapid improvement of smart grids, higher requirements are put forward to the recognition methods in detection accuracy and real-time performance. However, the conventional recognition methods are fail to meet the demands since they always have drawbacks in detection performance. To improve the electrical component identifi cation capability, a novel detection method based on Feature Enhanced You Only Look Once v4-tiny (FEYOLOv4-tiny) is proposed in this study. Here, YOLOv4-tiny is employed as the prototype of the proposed network, whereas enhancement module is designed to improve the feature extraction capability. Moreover, frequency channel attention and spatial attention module are utilized to capture the informative and discriminatory features. Experimental results indicate that our proposed method outperforms other lightweight networks in detection accuracy with almost the same real-time performance, especially for the small targets with complex background. Over all, FEYOLO v4-tiny is effi cient in electrical component identifi cation and has signifi cant application prospects in power inspection.
A Pattern-based Query Strategy in Wireless Sensor Network
( Yanhong Ding ),( Tie Qiu ),( Weifeng Sun ),( He Jiang ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.6
Pattern-based query processing has not attracted much attention in wireless sensor network though its counterpart has been studied extensively in data stream. The methods used for data stream usually consume large memory and much energy. This conflicts with the fact that wireless sensor networks are heavily constrained by their hardware resources. In this paper, we use piece wise representation to represent sensor nodes` collected data to save sensor nodes` memory and to reduce the energy consumption for query. After getting data stream`s and patterns` approximated line segments, we record each line`s slope. We do similar matching on slope sequences. We compute the dynamic time warping distance between slope sequences. If the distance is less than user defined threshold, we say that the subsequence is similar to the pattern. We do experiments on STM32W108 processor to evaluate our strategy`s performance compared with naive method. The results show that our strategy`s matching precision is less than that of naive method, but our method`s energy consumption is much better than that of naive approach. The strategy proposed in this paper can be used in wireless sensor network to process pattern-based queries.