Research on Tagging Recommendation Algorithm Based on Relevance and Diversity

Guo Zheng-Hong,Ma Xinhua,Zhao Kai 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.10

The traditional recommendation algorithms of image tagging ignore the diversity between the visual content information and the tags recommended, which causes the recommended results have the problem of tag ambiguity, tag redundancy and so on. Therefore, this paper proposes the recommendation algorithm of image tagging based on relevance and diversity. The algorithm defines the relevance and diversity of a label set, and selects a label set which can reasonably balance the relevance and diversity to recommend to the user. The experimental results show that this algorithm improves the relevance between the recommended results and the image, and makes the recommended results be able to reflect the image content thoroughly at the same time.

Research of NCS Algorithm in Cloud Demand System

Guo Zheng-Hong,Ma Xinhua 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.6

In order to reduce the bandwidth overhead and the node request rejection rate of the cloud video-on-demand server, this paper builds the cloud auxiliary framework and proposes the neighbors and chunks selection algorithm, which contains the node selection sub-algorithm and the block download sub-algorithm. The buffer-based node selection algorithm treats the download point as the benchmark to effectively find the neighbor nodes that can provide the video data, and the buffer-based block download algorithm calculates the required minimum buffer values of the two different kinds of block download strategies under the framework, which provides the theoretical basis for the download method of the video block. The experimental results show that the algorithm in this paper achieves good effects in the aspects of the bandwidth overhead of the server, the request rejection rate and the download rate.

A SVPWM algorithm based on four‑switch three‑phase inverter for PMSM under the imbalance of bus capacitor voltage

Shoucheng Huang,Xinhua Guo,Rongkun Wang,Yunhui Mei 전력전자학회 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.12

In a four-switch three-phase inverter-powered permanent magnet synchronous motor system, the capacitor voltage fluctuates due to the unequal capacitance and the charging and discharging of the bus capacitor. As such, the accuracy of motor vector control becomes significantly affected and even causes the shutdown of the motor drive system. Therefore, this study proposed a space vector PWM (SVPWM) algorithm that considers capacitor voltage imbalance. In the case of voltage basic vector offset, this algorithm first constructs a new orthogonal voltage basic vector and takes the offset modulation range as the constraint condition to synthesize a new target voltage vector. Compared with the traditional SVPWM algorithm, the proposed SVPWM algorithm controls the capacitor voltage fluctuation range in a reasonable range, simplifies the calculation, improves the three-phase stator current asymmetry, and reduces the current harmonic content. Simulation and experimental results demonstrate the effectiveness and feasibility of the proposed SVPWM algorithm.

Hybrid PWM Modulation Technology Applied to Three-Level Topology-Based PMSMs

Yuanxi Chen,Xinhua Guo,Jiangyu Xue,Yifeng Chen 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of aninverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee highperformance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique thatdetermines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. Inthis paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse widthmodulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybridPWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under lowspeed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the controlsystem. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particularcurrent harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transitionbetween the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed controlmethod.

Hybrid PWM Modulation Technology Applied to Three-Level Topology-Based PMSMs

Chen, Yuanxi,Guo, Xinhua,Xue, Jiangyu,Chen, Yifeng The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of an inverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee high performance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique that determines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. In this paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse width modulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybrid PWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under low speed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the control system. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particular current harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transition between the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed control method.

Purification and Identification of a Novel Antifungal Protein Secreted by Penicillium citrinum from the Southwest Indian Ocean

( Chao Wen ),( Wen Bin Guo ),( Xinhua Chen ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.10

A novel antifungal protein produced by the fungal strain Penicillium citrinum W1, which was isolated from a Southwest Indian Ocean sediment sample, was purified and characterized. The culture supernatant of P. citrinum W1 inhibited the mycelial growth of some plant pathogenic fungi. After saturation of P. citrinum W1 culture supernatants with ammonium sulfate and ion-exchange chromatography, an antifungal protein (PcPAF) was purified. The N-terminal amino acid sequence analysis showed that PcPAF might be an unknown antifungal protein. PcPAF displayed antifungal activity against Trichoderma viride, Fusarium oxysporum, Paecilomyces variotii, and Alternaria longipes at minimum inhibitory concentrations of 1.52, 6.08, 3.04, and 6.08 μg/disc, respectively. PcPAF possessed high thermostability and had a certain extent of protease and metal ion resistance. The results suggested that PcPAF may represent a novel antifungal protein with potential application in controlling plant pathogenic fungal infection.

Exogenous Indole Regulates Lipopeptide Biosynthesis in Antarctic Bacillus amyloliquefaciens Pc3

( Lianshuai Ding ),( Song Zhang ),( Wenbin Guo ),( Xinhua Chen ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.5

Bacillus amyloliquefaciens Pc3 was isolated from Antarctic seawater with antifungal activity. In order to investigate the metabolic regulation mechanism in the biosynthesis of lipopeptides in B. amyloliquefaciens Pc3, GC/MS-based metabolomics was used when exogenous indole was added. The intracellular metabolite profiles showed decreased asparagine, aspartic acid, glutamine, glutamic acid, threonine, valine, isoleucine, hexadecanoic acid, and octadecanoic acid in the indole-treated groups, which were involved in the biosynthesis of lipopeptides. B. amyloliquefaciens Pc3 exhibited a growth promotion, bacterial total protein increase, and lipopeptide biosynthesis inhibition upon the addition of indole. Besides this, real-time PCR analysis further revealed that the transcription of lipopeptide biosynthesis genes ituD, fenA, and srfA-A were downregulated by indole with 22.4-, 21.98-, and 26.0-fold, respectively. It therefore was speculated that as the metabolic flux of most of the amino acids and fatty acids were transferred to the synthesis of proteins and biomass, lipopeptide biosynthesis was weakened owing to the lack of precursor amino acids and fatty acids.

In Situ Growth of Plasmonic Gold Nanoparticles for the Direct and Sensitive Colorimetric Assay of Glucose

Shaohuang Weng,Feng Feng,Honghui Guo,Namei Wu,Yanjie Zheng,Zhen Lin,Xinhua Lin 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.3

Gold nanoparticles (Au NPs)-based colorimetric assay for the highly sensitive and selective detection of glucose has been conducted. The sensing, which was based on the in situ growth of Au NPs in the presence of glucose, was developed with the solution changing from colorless to red. This change could be observed with the naked eye or a ultraviolet–visible (UV–vis) spectrophotometer. Moreover, adding trace amounts of Tween-20 kept Au NPs well spaced. Under the optimal assay conditions, the absorbance of Au NPs at 550 nm was proportional to glucose concentration within 400–1800 μM with a linear regression equation, and the detection limit was 6.28 μM. Some common interfering compounds in beverages, including other sugars, food additives, and amino acids, did not affect glucose sensing. Therefore, the proposed Au NP-based colorimetric assay could be successfully used to determine glucose in beverages.

Seroprevalence of Dirofilaria immitis in Cats from Liaoning Province, Northeastern China

Honglie Hou,Lili Cao,Wenzhi Ren,Dansheng Wang,He Ding,Juan You,Xinhua Yao,Hang Dong,Yanbing Guo,Shuxian Yuan,Xi-Chen Zhang,Pengtao Gong 대한기생충학ㆍ열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.6

The present study was performed to investigate the seroprevalence and risk factors for Dirofilaria immitis infection in cats from Liaoning province, northeastern China. From October 2014 to September 2016, sera of 651 cats, including 364 domestic cats and 287 feral cats (332 females and 319 males) were assessed. They were tested for the presence of D. immitis antigen using SNAP Heartworm RT test kit. In this population, the average prevalence was 4.5%. Age and rearing conditions (feral or domestic) were found to be associated with the prevalence of D. immitis. The prevalence was significantly higher in feral cats compared with domestic cats (8.4% vs 1.4%, P<0.01). There was no significant difference between males and females (4.7% vs 4.2%, P>0.05), but older cats (≥3 years old) showed a statistically higher prevalence compared with younger cats (<3 years old) in feral populations (16.8 vs 2.4%, P<0.01), while the difference between the age groups was not statistically significant in domestic cats (2.4% vs 0.51%, P>0.05), all these results suggest that outdoor exposure time may be one of the most important factors for D. immitis prevalence in cats. Results reveal that D. immitis are prevalence in domestic and feral cats in northeastern China, which indicates that appropriate preventive measures should be taken to decrease the incidence of feline heartworm disease in Liaoning province, northeastern China.

A Novel Anti-Microbial Peptide from Pseudomonas, REDLK Induced Growth Inhibition of Leishmania tarentolae Promastigote In Vitro

Yanhui Yu,Panpan Zhao,Lili Cao,Pengtao Gong,Shuxian Yuan,Xinhua Yao,Yanbing Guo,Hang Dong,Weina Jiang 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.2

Leishmaniasis is a prevalent cause of death and animal morbidity in underdeveloped countries of endemic area. However, there is few vaccine and effective drugs. Antimicrobial peptides are involved in the innate immune response in many organisms and are being developed as novel drugs against parasitic infections. In the present study, we synthesized a 5-amino acid peptide REDLK, which mutated the C-terminus of Pseudomonas exotoxin, to identify its effect on the Leishmania tarentolae. Promastigotes were incubated with different concentration of REDLK peptide, and the viability of parasite was assessed using MTT and Trypan blue dye. Morphologic damage of Leishmania was analyzed by light and electron microscopy. Cellular apoptosis was observed using the annexin V-FITC/PI apoptosis detection kit, mitochondrial membrane potential assay kit and flow cytometry. Our results showed that Leishmania tarentolae was susceptible to REDLK in a dose-dependent manner, disrupt the surface membrane integrity and caused parasite apoptosis. In our study, we demonstrated the leishmanicidal activity of an antimicrobial peptide REDLK from Pseudomonas aeruginosa against Leishmania tarentolae in vitro and present a foundation for further research of anti-leishmanial drugs.