A Novel Solution to Test Face Recognition Methods on the Training Data Set

Weiwei Wu 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.9

In modern life, we need better techniques based on biometric features recognition such as face recognition, fingerprint recognition and iris recognition. We present a method which can be used for face recognition or verification applications. The method can solve the problem that when the number of data categories is large and each number of the category used for training is small. As the conventional four stages, face detection, face alignment, face representation and face classification, we propose a Siamese architecture especially for the representation stage and use a one-against-one support vector machine for the classification stage. LFW dataset is used for training and testing which gets a considerable result. And we also test our system on other face dataset, which has a high accuracy on the recognition.

Coexistence of OSCR-Based IR-UWB System with IEEE 802.11a WLAN

Weiwei Wu,Han Huang,Huarin Yin,Weidong Wang,Dongjin Wang 한국전자통신연구원 2006 ETRI Journal Vol.28 No.1

Impulse radio (IR) is a competitive candidate for ultra-wideband (UWB) systems. In this letter, we evaluated the coexistence of an IR-UWB system based on an orthogonal sinusoidal correlation receiver (OSCR) with an IEEE 802.11a WLAN through a detailed simulation. The coexistence performance of the two systems is characterized in terms of the receiver’s bit-error rates. Then, some approaches to interference mitigation are discussed.

Let-7c miRNA Inhibits the Proliferation and Migration of Heat-Denatured Dermal Fibroblasts Through Down-Regulating HSP70

Shifeng Wu,Tao Jiang,Xingang Wang,Weiwei Wu,Fan Zhang 한국분자세포생물학회 2016 Molecules and cells Vol.39 No.4

Wound healing is a complex physiological process necessitating the coordinated action of various cell types, signals and microRNAs (miRNAs). However, little is known regarding the role of miRNAs in mediating this process. In the present study, we show that let-7c miRNA is decreased in heat-denatured fibroblasts and that inhibiting let-7c expression leads to the increased proliferation and migration of dermal fibroblasts, whereas the overexpression of let-7c exerts an opposite effect. Further investigation has identified heat shock protein 70 as a direct target of let-7c and has demonstrated that the expression of HSP70 in fibroblasts is negatively correlated with let-7c levels. Moreover, down-regulation of let-7c expression is accompanied by up-regulation of Bcl-2 expression and down-regulation of Bax expression, both of which are the downstream genes of HSP70. Notably, the knockdown of HSP70 by HSP70 siRNA apparently abrogates the stimulatory effect of let-7c inhibitor on heat-denatured fibroblasts proliferation and migration. Overall, we have identified let-7c as a key regulator that inhibits fibroblasts proliferation and migration during wound healing.

Enhancement of Thermal Stability and Bending Ductility of Fe–Si–B Amorphous Ribbons with Minor Y Addition

Weiwei Dong,Xiaowei Wu,Mi Yan 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

The influences of minor Y addition on the thermal stability, crystallization behavior, magnetic property and bending ductilityof Fe–Si–B amorphous ribbons have been systematically investigated. The results show that all the ribbons with Y additionare fully amorphous structure, and the introduction of Y can enhance the glass forming ability of Fe–Si–B amorphous alloy. With Y addition, crystallization temperature of the first and second phase shift to high temperature side, the temperatureinterval between the two crystallization peaks are enlarged, the third phase transitions process of Fe–Si–B amorphous alloywith Y addition corresponds to the precipitation of Fe3Bphase. The activation energy of the first and second phase calculatedby Kissinger’s formula increased with Y addition. Appropriate Y addition is beneficial for Ms. The measured coercivity Hcgradually decreased with the Y addition increased. The amorphous alloys exhibit good bending ductility in the quenchedstate. The ductile to brittle temperature increase to 300 °C with 1 at% Y addition. Furthermore, the mechanism of ductile tobrittle for amorphous alloy was discussed.

Effect of Cu-Coated Short Carbon Fibers on the Mechanical and Electrical Properties of the Epoxy Composites

Weiwei Li,Lei Liu,Bin Shen,Yating Wu,Wenbin Hu 한국고분자학회 2012 Macromolecular Research Vol.20 No.4

In this study, short carbon fiber (SCF)-reinforced epoxy composites were prepared through changing of the fiber content (0.1-0.7 wt%). An electrodeposition process was used to produce Cu-coated SCFs. To investigate the effect of Cu-coated SCFs on the composite mechanical and electrical properties, we prepared two kinds of reinforcements:SCFs treated by 400 oC (400 oC-treated SCFs) and Cu-coated SCFs (Cu-SCFs). Fracture characteristics of the composites revealed that the Cu coating and the epoxy matrix had a better interface, meaning that the tensile and bending strength results were better in epoxy/Cu-SCFs composites than those in epoxy/400 oC-treated SCFs composites. The 400 oC-treated SCFs decreased the electrical resistivity of the epoxy composites compared to the pure epoxy. However the epoxy/Cu-SCFs composites had lower electrical resistivity than epoxy/400 oC-treated SCFs with the same fiber content.

Facile Synthesis of CdTe Nanorods from the Growth of Te Nanorods

Weiwei Xu,Jinzhong Niu,Guimin Tian,Xinghui Wu,Yongguang Cheng,Xiaoyang Hu,Haoshan Hao 대한화학회 2017 대한화학회지 Vol.61 No.4

One-dimensional CdTe nanorods (NRs) are obtained by the reaction of various Cd precursors with single crystalline Te nanorod templates, which are pre-synthesized from Te precursors by a simple and reproducible solvothermal method. Throughout the process, the diffraction intensity of different crystal facets of single crystalline Te NRs varied with reaction times. Finally, by alloying Cd ions along the axial direction of Te NRs, polycrystalline cubic phase CdTe NRs with diameters of 80–150 nm and length up to 1.2–2.4 μm are obtained. The nucleation and growth processes of Te and CdTe NRs are discussed in details, and their properties are characterized by XRD, SEM, TEM, Raman scattering, and UV-vis absorption spectra. It was found that the key elements of synthesizing CdTe NRs such as reaction temperatures and Cd sources will strongly influence the final shape of CdTe NRs.

Facile Synthesis of CdTe Nanorods from the Growth of Te Nanorods

Xu, Weiwei,Niu, Jinzhong,Zheng, Shuang,Tian, Guimin,Wu, Xinghui,Cheng, Yongguang,Hu, Xiaoyang,Liu, Shuaishuai,Hao, Haoshan Korean Chemical Society 2017 대한화학회지 Vol.61 No.4

One-dimensional CdTe nanorods (NRs) are obtained by the reaction of various Cd precursors with single crystalline Te nanorod templates, which are pre-synthesized from Te precursors by a simple and reproducible solvothermal method. Throughout the process, the diffraction intensity of different crystal facets of single crystalline Te NRs varied with reaction times. Finally, by alloying Cd ions along the axial direction of Te NRs, polycrystalline cubic phase CdTe NRs with diameters of 80-150 nm and length up to $1.2-2.4{\mu}m$ are obtained. The nucleation and growth processes of Te and CdTe NRs are discussed in details, and their properties are characterized by XRD, SEM, TEM, Raman scattering, and UV-vis absorption spectra. It was found that the key elements of synthesizing CdTe NRs such as reaction temperatures and Cd sources will strongly influence the final shape of CdTe NRs.

A management strategy for solar panel - battery - super capacitor hybrid energy system in solar car

Bin Wu,Fang Zhuo,Fei Long,Weiwei Gu,Yang Qing,YanQin Liu 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents an application of solar energy - battery - super-capacitor hybrid energy storage system in solar electric vehicles. The key point is the proposed energy management control algorithm. The entire system consists of a solar panel, a boost converter, a battery, a super capacitor, a bi-directional DC/DC converter, and a brushless DC motor. This paper gives the details of the control strategy to cooperate the three energy sources or storage devices: solar panel, battery and super capacitor. A hysteretic control algorithm for battery charging by solar panel is given. A novel control method for bi-directional DC/DC is proposed to keep the battery discharging current within a certain limit and make full use of super capacitor. The switching transient between super-capacitor charging mode and discharging mode is also presented. Both simulation and experimental results demonstrate the effectiveness of the proposed strategy.

Characteristic profiles of biofilm, enterotoxins and virulence of Staphylococcus aureus isolates from dairy cows in Xinjiang Province, China

Yehui Wu,Jing Li,Mengfan Qiao,Dan Meng,Qingling Meng,Jun Qiao,Xingxing Zhang,Lixia Wang,Kuojun Cai,Jinsheng Zhang,Zaichao Zhang,Weiwei Yu,Xuepeng Cai 대한수의학회 2019 Journal of Veterinary Science Vol.20 No.6

As an important zoonotic pathogen, Staphylococcus aureus (S. aureus) infection has led to serious mastitis and endometritis in infected dairy cows. HereIn this study, a total of 164 strains of S. aureus were isolated from dairy cows in Xinjiang Province, China, and subjected to assays to determine of drug susceptibility and biofilm (BF) formation ability. The eEnterotoxin-related genes were detected, and then the transcription levels of genes related to BF formation were also determined by using reverse transcription-quantitative polymerase chain reactionPCR. Moreover, the pathogenicity of these isolates with different BF formation abilities was determined via by measuring their hemolysis activity, half lethal dose (LD50) and organ bacterial load, respectively. The results showed that 83.4 % of S. aureus isolates could form BF. Among them, 40.8 % of the strains had weak BF formation ability, and most strains with a strong BF formation ability were ica gene carriers. The S. aureus isolates displayed multidrug resistance and their drug resistance was positively correlated with their BF formation ability. Moreover, 96.3 % of the S. aureus isolates carried enterotoxin genes. Among them, the detection rates of the novel enterotoxin genes were higher than thoseat of conventional enterotoxin genes. Furthermore, the isolates with a strong BF formation ability had higher LD50 but lower hemolysis ability and organ bacterial load than thoseat of the isolates with weak or no BF ability. However, those isolates without BF ability caused produced more severe pathological changes than thoseat of the isolates with strong BF formation ability. These findings suggested that higher frequencies of BF ability and presence of novel enterotoxin genes were are important characteristics of S. aureus isolates from dairy cows in Xinjiang Province, China, and such isolateswhich may posed potential threats to food safety.

Two New Bibenzyl Glucosides from Dendrobium chrysotoxum

Fa-Wu Dong,Huai-Rong Luo,Qin-Li Wan,Feng-Qing Xu,Weiwei Fan,Kai-Jin Wang,Ning Li,Jiang-Miao Hu 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.7

Two new bibenzyl glucosides, 3,3',4',5-tetramethoxybibenzyl-4-O-β-D-glucopyranoside (1) and 3,4,4',5- tetramethoxybibenzyl-3'-O-β-D-glucopyranoside (2), together with five known ones, chrysotobibenzyl (3), erianin (4), chrysotoxine (5), gigantol (6) and tristin (7) were isolated from the stems of Dendrobium chrysotoxum. The structures of those compounds were elucidated by extensive spectroscopic analysis. Moreover, compounds 1-7 were assessed for inhibitory activity of two enzymes-AChE (acetylcholine esterase) and BChE (butyrylcholine esterase).