Study on Different Representation Methods for Subspace Segmentation

Jiangshu Wei,Mantao Wang,Qianqian Wu 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.1

With many engineering and science application problems, we must deal with a lot of high-dimensional data, such as videos, images, web documents, text, etc. In the areas of computer vision, image processing and machine learning, high-dimensional data are widespread. However, it is very hard for obtaining meaningful learning and inference from these high-dimensional data directly, the computational complexity of high-dimensional data is often exponential. However, under many conditions, high-dimensional data lie in low-dimensional data corresponding to some classes of the data. Thus, finding the low-dimensional structure from the high-dimensional data is very important. The aim of subspace segmentation is to cluster data that lie in a union of low-dimensional subspaces. In recent years, based on the research of representation methods, many subspace segmentation algorithms appeared. Although these methods are all effective for handling subspace segmentation problems, they all have advantages and disadvantages. This paper focuses on the performance comparison of different subspace segmentation algorithms currently used in handling subspace segmentation problems and views other conventional methods that can be applied in this field.

Numerical Simulation of the Coalescence Behavior of Intermittent Structures with Fissures

Qianqian Dong,Yulin Wu,Qiyang Chen 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

To further study the failure behavior of the rock-like materials containing intermittent fissures subjected to uniaxial compression, 3D printing technology was adopted to manufacture specimens with prefabricated kinked and straight fissures (K-S fissure). The order of average peak strength was -45o > -90o > +90o > +45o. The influence of different parameters, including the effective length and inclination angle of branch fissure, on the coalescence pattern was discussed. Results showed that two failure modes were observed: Model I represented tensile-shear composite failure in the rock bridge area, while Model II showed non-coalescence occurring. The effective length parameter presented a relatively larger influence than the inclination angle on the failure behavior. Additionally, Model I was discovered to tend to occur in the rock bridge region when the branch fissure turned anticlockwise. Based on numerical simulation using the Realistic Failure Process Analysis (RFPA2D), a quick damage criterion approach was proposed to estimate the coalescence behavior in the rock bridge, which was beneficial to determine coalescence pattern and failure behavior. Based on the curve fitted by the simulation, the coalescence pattern of cracks initiated from pre-existing intermittent fissures occurs in the tensile-shear composite fracture pattern, while non-coalescence occurs in the rock bridge below the curve.

De novo Assembly and Analysis of Amur Sturgeon (Acipenser schrenckii) Transcriptome in Response to Mycobacterium Marinum Infection to Identify Putative Genes Involved in Immunity

( Qianqian Zhang ),( Xiehao Wang ),( Defeng Zhang ),( Meng Long ),( Zhenbing Wu ),( Yuqing Feng ),( Jingwen Hao ),( Shuyi Wang ),( Qian Liao ),( Aihua Li ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.8

Fish mycobacteriosis is a common bacterial disease in many species of freshwater and marine fish and has caused severe loss of fish production. Mycobacterium marinum has been the most prevalent pathogen observed in several outbreaks of mycobacteriosis of farmed sturgeons in China. However, the immune responses and pathology of sturgeons in mycobacterial infection are rarely studied. Therefore, we used the Illumina RNA-seq method to analyze the transcriptome profile of Acipenser schrenckii challenged with Mycobacterium marinum. To begin, 168,220 non-redundant contigs were acquired from the infection and control groups, and among these, 33,225 contigs have acquired annotations. A total of 4,043 differently expressed (DE) contigs between the two groups were identified, and among these, 2479 were upregulated and 1564 were down-regulated in the infected fish. A total of 1,340 DE contigs with acquired annotations in KEGG were enriched for 124 pathways including the TNF signaling pathway, and the Toll-like receptor signaling pathway. The roles of DE genes involved in significant pathways and other processes were discussed. The 2,209 DE contigs that have yet to acquire proper annotation may represent candidate genes associated with infection in sturgeons and are expected to serve as immunogenetic resources for further study. To our best knowledge, this is the first transcriptome study on sturgeons under bacterial infection.

Epigenetically Modified Bone Marrow Stromal Cells in Silk Scaffolds Promote Craniofacial Bone Repair and Wound Healing

Han, Qianqian,Yang, Pishan,Wu, Yuwei,Meng, Shu,Sui, Lei,Zhang, Lan,Yu, Liming,Tang, Yin,Jiang, Hua,Xuan, Dongying,Kaplan, David L.,Kim, Sung Hoon,Tu, Qisheng,Chen, Jake Mary Ann Liebert 2015 Tissue engineering. Part A Vol.21 No.15

<P>Epigenetic regulation of gene expression is a central mechanism that governs cell stemness, determination, commitment, and differentiation. It has been recently found that PHF8, a major H4K20/H3K9 demethylase, plays a critical role in craniofacial and bone development. In this study, we hypothesize that PHF8 promotes osteoblastogenesis by epigenetically regulating the expression of a nuclear matrix protein, special AT-rich sequence-binding protein 2 (SATB2) that plays pivotal roles in skeletal patterning and osteoblast differentiation. Our results showed that expression levels of PHF8 and SATB2 in preosteoblasts and bone marrow stromal cells (BMSCs) increased simultaneously during osteogenic induction. Overexpressing PHF8 in these cells upregulated the expression of SATB2, Runx2, osterix, and bone matrix proteins. Conversely, knockdown of PHF8 reduced the expression of these genes. Furthermore, ChIP assays confirmed that PHF8 specifically bound to the transcription start site (TSS) of the SATB2 promoter, and the expression of H3K9me1 at the TSS region of SATB2 decreased in PHF8 overexpressed group. Implantation of the BMSCs overexpressing PHF8 with silk protein scaffolds promoted bone regeneration in critical-sized defects in mouse calvaria. Taken together, our results demonstrated that PHF8 epigenetically modulates SATB2 activity, triggering BMSCs osteogenic differentiation and facilitating bone formation and regeneration in biodegradable silk scaffolds.</P>

Performance of Rock-like Materials Containing Filled Kinked Fissures under Uniaxial Tension at Failure

Yulin Wu,Qianqian Dong,Jian He,Qiyang Chen 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

To investigate the tensile failure phenomenon of rock masses with filled natural defects, the mechanical behavior of 3D printed rock-like materials containing filled kinked fissures under uniaxial tension was identified. Different inclination angles of branch fissure were considered, and cement and gypsum slurry were selected as the infilling materials. It was found that filling materials enhanced the strength of the specimen, which presented to be cement filling > gypsum filling > no filling. The change of inclination angle of branch fissure had significant influence on the strength and failure mode of the specimen and the strength order was -135o> -45o > 90o and +45o > 90o > +135o. Two types of failure pattern, namely tip failure and non-tip failure, were observed in the experiment. Three types of newborn cracks were identified using a high-speed camera. The result achieved by using the digital image correlation technology indicated that different filling conditions led to the position change of high-strain zone. The displacement field of the filled specimen developed from being continuous to being discontinuous. Furthermore, the extended finite element method was adopted to simulate the filled and unfilled specimens, consistent with the experimental results. This study can provide a reliable reference for studying the tensile stress zones in rock exploration.

Investigation of the impact of splitter blades on a low specific speed pump for fluid-induced vibration

Guitao Zeng,Qianqian Li,Peng Wu,Bo Qian,Bin Huang,Shiyang Li,Dazhuan Wu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

Low specific speed centrifugal pumps are widely applied in the chemical industry and agricultural irrigation fields. The vibration characteristics are of great importance for centrifugal pumps. Apart from rotor installation, fluid-induced vibrations caused by internal flow also play an important role in the vibration performance, and special attention should be paid to low specific speed centrifugal pumps for long and narrow meridian flow channels where secondary flows are easy to generate. In this paper, splitter blades were studied for decreasing the pressure and radial force fluctuations of a low specific speed centrifugal pump at the design point, both numerically and experimentally. Numerical simulations based on the Reynolds averaged Navier–Stokes (RANS) turbulent model were performed for fluid-field analysis. The steady state and unsteady simulations were computed based on ANSYS Fluent. Here, the circumferential location, leading edge location, and the deflection angle of the splitter blades were considered to suppress the secondary flow and to reduce vibration. The experiments show the effectiveness of splitter blades for decreasing fluid-induced vibrations.

The differentiation of cellular structure during encystment in the soil hypotrichous ciliate Australocirrus cf. australis (Protista, Ciliophora)

Qili Li,Xinpeng Fan,Qianqian Sun,Na Wu,Bing Ni,Fukang Gu 한국통합생물학회 2017 Animal cells and systems Vol.21 No.1

Ciliates are able to form resting cysts as a survival strategy in response to stressful environmental factors. Studies on the characteristics of cellular structure during encystment may provide useful information for further understanding of the regulatory mechanism of cellular patterns and supply new clues regarding the phylogeny of ciliates. Scanning and transmission electron microscopies were used to observe the ultrastructure of cells during encystment of the soil ciliate Australocirrus cf. australis. The dedifferentiation of ciliature was revealed for the first time. Ciliary shafts first shortened, and the remaining ciliature, including basal bodies and the fibrillar cirral basket, retracted into the cytoplasm and was surrounded by the autophagic vacuoles and then gradually digested. A large number of autophagic vacuoles were observed in mature resting cysts. Autophagy might not only be necessary for the differentiation of cellular structures during encystment but might also be important to sustain the basic life activities in the resting stage. Australocirrus cf. australis formed a kinetosome-resorbing cyst and contained four layers in the cyst wall: the ectocyst, mesocyst, endocyst and granular layer. The ciliature resorbing state and the number of layers in the cyst wall were consistent with those found in other oxytrichous ciliates. However, the phenomenon wherein the two macronuclear nodules are not fused during encystment is not commonly observed among oxytrichids. Additionally, the octahedral granules in the mesocyst of this species exhibit different morphology from the congeners.

Heat transfer characteristics of single-ring closed PHP

Lipeng Wang,Yue Cai,Qianqian Zhang,Sheng Shi,Lin Wu,Hongren Zhan 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.4

In order to solve the problem of heat dissipation in the current industry, a single ring closed pulsating heat pipe (PHP) was simulated in this paper. Firstly, the geometry model and numerical simulation model of single ring closed cycle PHP were established to obtain the temperature change rule of PHP and the position motion state of the vapor-plug and liquidcolumn in the tube. At the same time, a test bench was set up to verify the accuracy of the simulation results. The time series data of temperature and position of vapor-plug and liquidcolumn in PHP are extracted, and the chaotic characteristics of PHP are obtained. The results show that with the increase of the heating power, the motion state of the working fluid, the chaotic attractor and Lyapunov index have all changed significantly. The results provide a foundation for further research on the features and mechanism of PHP.

A Novel Action Recognition Method Based on Improved Spatio-Temporal Features and AdaBoost-SVM Classifiers

Xiaofei Ji,Lu Zhou,Qianqian Wu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.5

Most of existed action recognition methods based on spatio-temporal descriptors have ignored their spatial distribution information. However the spatial distribution information usually is very useful to improve the discriminative ability of the motion representation. An improved spatio-temporal is proposed in this paper by combining local spatio-temporal feature and global positional distribution information (FEA) of interest points. Furthermore, in order to improve the classifier’s performance, an Adaboost-SVM method is utilized to recognize the human actions by using the proposed motion descriptor. The proposed recognition method is tested on the public dataset of KTH. The test results verified the proposed representation and recognition method can more accurately describe and recognize the human motion.

Genome-wide identification and comparative analysis of Alfin-like transcription factors in maize

Wei Zhou,Jiandong Wu,Qianqian Zheng,Yingli Jiang,Min Zhang,Suwen Zhu 한국유전학회 2017 Genes & Genomics Vol.39 No.3

Members of the Alfin-like (AL) transcription factor family, which contain a highly conserved DUF3594 domain and a PHD-finger motif, play important roles in the responses of plants to abiotic stress during various metabolic and physiological processes. To date, no systematic, comprehensive study of this family has been reported in maize. In this study, we identified 18 nonredundant ZmAL genes and classified them into four groups. These genes are unevenly distributed among all ten maize chromosomes except chromosome 9. Our results suggest that segmental duplication has played an important role in the expansion of the AL family in maize. Ka/Ks ratio analysis showed that most duplicated ZmALs have undergone large-scale purifying selection in the maize genome. We detected interspecies microsynteny among three graminaceous species, suggesting that there were independent duplication events in addition to the whole-genome duplication of the maize genome. Furthermore, microarray analysis showed that most ZmALs are differentially expressed in diverse tissues and stages. We also performed expression profiling of the ZmALs under salt, cold and drought stress conditions using quantitative reverse-transcription PCR (qRT-PCR). The results of this study provide useful clues for further functional analysis of the AL gene family in maize.