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The two-grid algorithm of the finite volume element method for second-order indefinite elliptic problems DAI Zhen-xiang J4    Abstract （1922）      PDF（pc） （240KB）（53963）       Save The two-grid algorithm of the finite volume element method for second-order indefinite elliptic problems in R2 was presented ,based on the P1 nonconforming element.The following error estimated in the H1-norm between the solution of the two-grid and the finite volume element appoximation of the elliptic problem were derived::‖uh-uh‖1,h≤CH2‖f‖1,‖u-uh‖1,h≤C(h+H2)‖f‖1. Related Articles | Metrics

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Characterization and structural control of metalbased nanomaterials YANG Jun JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2013, 48 (1): 1-22.   DOI: 10.6040/j.issn.1671-9352.9.2012.001 Abstract （1877）      PDF（pc） （6800KB）（9028）       Save The common analytical and characteristic techniques including UV-visible spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) are briefly introduced in this review article. In addition, in wetchemistry based syntheses, the approaches used to tune the structure of metal-based nanomaterials are categorized and discussed. Related Articles | Metrics

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Research advances of novel nonlinear optical crystals based on second-order Jahn-Teller effects (SOJT) ZHANG Jun-jie, ZHANG Zhong-han, TAO Xu-tang* JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2011, 46 (10): 99-120.   Abstract （3981）      PDF（pc） （5876KB）（7374）       Save Explorations of new inorganic second-order nonlinear optical (NLO) materials is one of the current frontier topics due to their optoelectronics application such as frequency shifting, optical modulating, telecommunications and signal processing. Since 1998, a series of noncentrosymmetric (NCS) and polar oxides containing cations susceptible to second-order Jahn-Teller (SOJT) distortions, specifically, octahedrally coordinated d0 transition metals (TMs: Mo6+,W6+,V5+,Nb5+,etc.) and cations with stereochemically active lone pairs (SCALP, e.g. I5+, Te4+, Se4+, Sn2+, etc.), were successfully synthesized. Many of these materials exhibit large powder second-harmonic generation (SHG) efficiencies (> 400×α-SiO2). This paper reviews the progress on the materials in the past decade, including the search for new materials and crystal growth. The materials are divided into three categories: NCS oxides containing one kind of SOJT cations (d0 or SCALP), NCS oxides containing both kinds of SOJT cations, and NCS oxides containing SOJT cations and other NCS building units such as borate πorbital systems, tetrahedral groups and d10 transition metal cations (Zn2+, Cd2+, Sn4+, etc.). Related Articles | Metrics

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A system of monitoring and protecting Android privacy leakage JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2016, 51 (9): 59-67.   DOI: 10.6040/j.issn.1671-9352.1.2015.293 Abstract （3145）      PDF（pc） （3349KB）（6715）       Save In order to protect the data of Android operating system, we present a system called FlowMonitor to monitor and protect privacy flow based on Android. FlowMonitor adds taint marks and identity tags onto data. Moreover, it is a real-time, dynamic monitoring system. In order to avoid leaking private data by collusion attack, it uses the mechanism of taint's identity authentication based on the idea of RBAC, and finds all probable malicious applications. Based on open and closed policies, labels were designed for each data to control the use of private data. The user can control applications using private data based on their choices. Evaluation results show that Flowmonitor out performs taint Droid. It can not only find out all probable malicious applications which steal private data by collusion attack, but also control applications using each private data. Extensive experimental results demonstrate that FlowMonitor effectively protects the user privacy. Reference | Related Articles | Metrics

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Two mixed conjugate gradient methods based on DY WANG Kai-rong, GAO Pei-ting JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2016, 51 (6): 16-23.   DOI: 10.6040/j.issn.1671-9352.0.2015.267 Abstract （2276）      PDF（pc） （623KB）（6696）       Save Based on DY method, two mixed conjugate gradient methods(GDY1 and GDY2)were proposed. The search directions generated by GDY1 and GDY2 are sufficiently decent directions under some specific conditions, and are global convergence with general wolf line search. Numerical experiments show that the new methods outperform DY conjugate gradient method. Reference | Related Articles | Metrics

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A sentiment analysis method based on a polarity lexicon ZHANG Cheng-gong 1, 2, LIU Pei-yu1, 2*, ZHU Zhen-fang1,2, FANG Ming1,2 J4    2012, 47 (3): 47-50.   Abstract （2461）      PDF（pc） （1026KB）（6667）       Save A polarity lexicon is the foundation of sentiment analysis and orientation analysis. An overall and effective polarity lexicon was constructed, including base lexicon, domain lexicon, network lexicon and modifier lexicon. The influence of modifiers to polarity words was studied. A sentiment analysis method based on a polarity lexicon was proposed, in which the modifiers and polarity words were combined into polarity phrases, and the phrase was used as the basic unit to compute the polarity of sentences and texts. Experimental results showed that the effect of orientation analysis using polarity lexicon raised in this paper was good. Related Articles | Metrics

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Advances of gene knockout in mice ZHANG Jian, YANG Xiao-mei*, GAO Jian-gang* JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2011, 46 (10): 183-196.   Abstract （2341）      PDF（pc） （1176KB）（6436）       Save With the successful completion of Human Genome Project (HGP),the biological research of postgenome era has a urgent need for an effective gene function analysis. Application of knockout mouse model provides a strong support for the study of gene function and the search for new therapeutic interventions in human disease. As two different techniques, gene targeting and gene trapping are producing knockout mice from embryonic stem cells (ES cells).The characteristic of gene trapping is highthroughput, random, and sequence tagged,while gene targeting is a specific gene knockout. Two decades ago, the first gene targeting and gene trapping mice were generated. In recent years, new tools for gene targeting and gene trapping are emerging, and the related organizations have been formed. These organizations can knock out genes in the mouse genome using these two methods. The international gene trap consortium (IGTC) and the knockout mouse project (KOMP) have begun to create a worldwide resource for research facilities, and plan to knock out all the mouse genes. KOMP organizers consider it as important as the HGP. From conventional gene targeting to high throughput conditional gene targeting, gene targeting methods have changed. The combined advantages of trapping and targeting enhance the gene trapping spectrum and gene targeting efficiency. As a newly developed insertional mutation system, transposons in trapping genes have more advantages than retrovirus. Emergence of the international knockout mouse consortium (IKMC) is the beginning of global cooperation. The organization is committed to systematically knock out all genes in the mouse genome, and then to carry out functional genomics studies. Related Articles | Metrics

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Sentiment classification method of Chinese Micro-blog based on semantic analysis YANG Jia-neng, YANG Ai-min, ZHOU Yong-mei JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2014, 49 (11): 14-21.   DOI: 10.6040/j.issn.1671-9352.3.2014.069 Abstract （2392）      PDF（pc） （1943KB）（6168）       Save By analyzing the structural features of Chinese Micro-blog, a sentiment classification method based on semantic analysis was proposed. For the proposed method, firstly, an emoticons sentiment lexicon and a network language sentiment lexicon were built. Then by using these two lexicons and the dependency parsing results, the sentiment expression Binary Tree was constructed. Finally, the sentiment strength, which was calculated by the established rules, was applied into the sentiment classification. Experimental results show that this method is effective and two built sentiment lexicons can better enhance the performance of the sentiment analysis system. Reference | Related Articles | Metrics

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Granular computing approach for formal concept analysis and its research outlooks LI Jin-hai, WU Wei-zhi JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2017, 52 (7): 1-12.   DOI: 10.6040/j.issn.1671-9352.0.2017.279 Abstract （2777）      PDF（pc） （1118KB）（5760）       Save Formal concept analysis is a useful mathematical method for knowledge representation and processing and its key tool is concept lattice. However, the construction of concept lattice takes exponential time complexity, which to some extent makes data processing inefficient and hinders fast development of this theory and its application. Granular computing is well-known for formation of granule, transformation of granule, and synthesis and decomposition of granule. Granular computing allows to consider problem by granularity in various levels, and strikes a balance between accuracy and time consuming in solving problem based on the practical requirements. The main research aim of granular computing approach for formal concept analysis is to incorporate these advantages of granular computing into traditional formal concept analysis for efficiently solving data analysis and processing. More specifically, this paper shows the main research topics of granular computing approach for formal concept analysis from the perspectives of Galois connection based granular computing model, object granule, attribute granule, relation granule, relation-based concept 山 东 大 学 学 报 (理 学 版)第52卷 - 第7期李金海,等:形式概念分析的粒计算方法及其研究展望 \=-granularity, granular rule, granular reduct, granular concept and learning, and concept granular computing systems. In addition, some challenging problems are also proposed for dealing with big data and cognitive learning. The obtained results will provide some references for the further study of granular computing approach of formal concept analysis. Reference | Related Articles | Metrics

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The application of flame combustion synthesis in the preparation of metal oxide and supported noble metal catalysts LI Jia-qi, DENG Yu-zhou, LIU Gang, YUE Ren-liang, YANG Jun, CHEN Yun-fa JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2016, 51 (1): 1-13.   DOI: 10.6040／j.issn.1671.9352.5.2015.004 Abstract （1345）      PDF（pc） （2388KB）（5614）       Save Flame combustion synthesis (FCS) is widely used to produce nanoparticles on a large scale, and has been applied in the preparation of carbon black and fumed silica. FCS is a versatile technique to be used but not limited in the specific field of catalyst preparation, gas sensor fabrication, luminant materials and antibacterial materials. In the review, we focus on the recent advances in using FCS for the catalyst preparation, including metal oxides and supported noble metals, and in the last section, we make some perspetives for the future developments of this promising synthetic technique. Related Articles | Metrics

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Survey on application of data mining via differential privacy KANG Hai-yan, MA Yue-lei JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2017, 52 (3): 16-23.   DOI: 10.6040/j.issn.1671-9352.2.2016.053 Abstract （2278）      PDF（pc） （932KB）（5263）       Save The latest results of differential privacy in data mining were surveyed. The basic concepts of differential privacy were introduced. It analyzes the differential privacys research in pattern mining, classification and cluster. It was focused that on the analysis of the principle of some important technology to achieve. And also it was made that comparative analysis of its strengths and weaknesses and algorithm complexity. Finally, the future research of difference privacy under the dynamic data publication and big data environments was discussed. Reference | Related Articles | Metrics

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Elliptic curves in cryptography: past, present and future… ZHANG Fang-guo J4    2013, 48 (05): 1-13.   Abstract （2241）      PDF（pc） （1139KB）（5100）       Save  From the beginning of the nineteenth century, mathematicians have put the elliptic curves as a research objective of algebra, geometry and number theory to study in-depth. So far, the theory of elliptic curves applied not only in the field of mathematics, and also widely in computing science, information security, physics and other fields. In this paper, we reviewed the application of elliptic curves in cryptography, from the primality testing, integer factorization to elliptic curve cryptosystem, bilinear pairing based cryptosystem and the quantum-resistant cryptosystems from elliptic curve isogenies. We introduced the basic principles and the status of these applications. Finally, we briefly discussed some open questions and possible future progress in this area. Related Articles | Metrics

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Short text clustering based on word embeddings and EMD HUANG Dong, XU Bo, XU Kan, LIN Hong-fei, YANG Zhi-hao JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2017, 52 (7): 66-72.   DOI: 10.6040/j.issn.1671-9352.1.2016.123 Abstract （2113）      PDF（pc） （1207KB）（4650）       Save Short text clustering plays an important role in data mining. The traditional short text clustering model has some problems, such as high dimensionality、sparse data and lack of semantic information. To overcome the shortcomings of short text clustering caused by sparse features、semantic ambiguity、dynamics and other reasons, this paper presents a feature based on the word embeddings representation of text and short text clustering algorithm based on the moving distance of the characteristic words. Initially, the word embeddings that represents semantics of the feature word was gained through training in large-scale corpus with the Continous Skip-gram Model. Furthermore, use the Euclidean distance calculation feature word similarity. Additionally, EMD(Earth Movers Distance)was used to calculate the similarity between the short text. Finally, apply the similarity between the short text to Kmeans clustering algorithm implemented in the short text clustering. The evaluation results on three data sets show that the effect of this method is superior to traditional clustering algorithms. Reference | Related Articles | Metrics

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Superconvergence and extrapolation of a lower order mixed finite method for nonlinear fourth-order hyperbolic equation ZHANG Hou-chao, ZHU Wei-jun, WANG Jun-jun JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2015, 50 (12): 35-46.   DOI: 10.6040/j.issn.1671-9352.0.2014.424 Abstract （1739）      PDF（pc） （688KB）（4511）       Save With the help of the bilinear element Q11 and the Q01×Q10 element, a lower order conforming mixed finite element approximation scheme is proposed for nonlinear fourth-order hyperbolic equation. Firstly, the existence and uniqueness of approximation solution are proved. Secondly, Based on the known high accuracy results of the about two elements, by use of derivative delivery techniques, the superclose with order O(h2) for both scalar unknown u and the diffusion term v=-Δu in H1-norm and the flux p=-∇u in L2-norm are derived, respectively. Moreover, the global superconvergence is obtained through interpolation post-processing technique. Finally, throught constructing a new asymptotic expansion formula of Q01×Q10 element and a suitable extrapolation scheme, the extrapolation solutions with order O(h3) are derived. Here, h is the subdivision parameter for the space. Reference | Related Articles | Metrics

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Research progress of corneal stromal wound healing FAN Ting-jun, BAI Su-ran JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2016, 51 (3): 1-10.   DOI: 10.6040/j.issn.1671-9352.0.2016.079 Abstract （1542）      PDF（pc） （1139KB）（4106）       Save Corneal stroma wound healing is a complex process involving cell apoptosis, migration, proliferation, differentiation, and extracellular matrix remodeling. Transforming growth factor β(TGF-β)system plays central roles in regulating the transformation of stromal cells and the fibrosis of stroma, and its dysregulation might be the main cause of stromal haze, scar formation and vision damage. Recently, great progress has been made in the study of corneal stromal wound healing, and various new therapies to attenuate stromal scar have also been developed. The process of corneal stromal wound healing, cellular phenotype transformation and its regulating factors, and strategies of excessive healing control are reviewed. Reference | Related Articles | Metrics

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Study and application of CAD technology in grade crossing vertical design WANG Gui-Jie, WANG Wen-De, TAO De-Li J4    2009, 44 (11): 79-82.   Abstract （1680）      PDF（pc） （1883KB）（4098）       Save he advantages and disadvantages are analysed on the basis of the grade crossing vertical design. Based on these design methods and computer aided design(CAD)technology,grid and contour line construction drawings are given by auto draft.Design results could be checked by the threedimensional Surface model based on the grids data and the threedimensional panoramic dynamic perspective picture.Finally, as certification, some road grade crossing engineering cases which are designed by these methods and CAD technology are presented. Related Articles | Metrics

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New methods for extracting emotional words based on distributed representations of words YANG Yang, LIU Long-fei, WEI Xian-hui, LIN Hong-fei JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2014, 49 (11): 51-58.   DOI: 10.6040/j.issn.1671-9352.3.2014.255 Abstract （2364）      PDF（pc） （3225KB）（4004）       Save Word-level sentiment analysis is a hot research interest in the field of affective computing. How to recognize and analyze these new emotional words automatically becomes an urgent problem. Firstly, statistics-based approach was used to identify the new words in Micro-blog corpus and then distributed representation of new words was trained by using neural network in order to get the correlation between words in corpus. Finally three vector-based methods to find new emotional words were introduced. The experimental results indicate that the proposed methods in this paper can be effectively used in discovery of new emotional words. Reference | Related Articles | Metrics

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The analysis of stock index sequence based on timing series model CUI Yu-quan, LI Pei-pei, LI Lin-lin J4    2013, 48 (8): 68-77.   Abstract （1372）      PDF（pc） （1320KB）（3962）       Save According to econometric time series model, the paper creatively proposed combing econometric model and fractal dimension based on Shanghai and Shenzhen stock market data system of great wisdom and statistical software EVIEWS during 2005-2009.It uses a high-dimensional chaotic characteristics of the stock index, using LP algorithm to determine the fractal dimension, using vector autoregressive VAR model to test unit root on the two stock markets in Shanghai and Shenzhen. According to AIC and SC information criterion, it determine the number of lags, predict the future trend of the stock market in dynamic and static state and obtain more reasonable results. Related Articles | Metrics

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Novel synthesis of C-terminal polypeptides by ISPPS method CHEN Lei, JIN Zhi, LIU Qiang, WANG Ming, WANG Pu* JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2014, 49 (1): 31-35.   DOI: 10.6040/j.issn.1671-9352.0.2013.235 Abstract （1707）      PDF（pc） （1456KB）（3921）       Save A facile approach for the preparation of polypeptide C-terminal derivatives by inverse solid phase peptide synthesis (ISPPS) was developed. This novel method combines both advantages of Fmoc-SPPS and TAEC technology, utilizes fewer functional group protection steps. In addition, the reaction can be carried out at room temperature under mild conditions and be easily monitored, and the working-up is simple and efficient. This method is complementary to the direct solid phase peptide synthesis. Several polypeptides as well as their C-terminal derivatives were efficiently prepared by this novel ISPPS method. Related Articles | Metrics

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A LBS privacy-preserving method for geo-fencing services YANG Song-tao, MA Chun-guang, ZHOU Chang-li, ZHANG Zong-li JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2014, 49 (09): 69-73.   DOI: 10.6040/j.issn.1671-9352.2.2014.065 Abstract （2217）      PDF（pc） （1753KB）（3844）       Save Geo-fencing technology is widely used in recommender systems, advertising push and other services. It has serious risk of personal privacy leakage threat. Focus on triggered query in Geo-fencing, the theories of the secure tripartite computation were applied in the research of the LBS privacy-preserving model, which follows the concept of location obfuscation and location k-anonymity and reaches the target of user's identity unlink-ability and location's untraced-ability. Location anonymity hidden problem and secret authentication problem were solved by computational geometry techniques and principles of cryptography in the triggered queries scenario. Theoretical analysis shows the model is security. From the perspective of privacy-preserving, the attackers do not get new knowledge from LBS system. Experiments demonstrate the computational efficiency and communication loads of this medel are superior to the traditional spatial-temporal cloaking methods. Reference | Related Articles | Metrics

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Algorithms of finite difference domain decomposition for two-heat equation LI Wan-shan, WANG Wen-qia* J4    2011, 46 (12): 1-5.   Abstract （1627）      PDF（pc） （1316KB）（3787）       Save Considering algorithms of finite difference domain decomposition for twodimensional heat equation, a new kind of explicitimplicit difference schemes which is of unconditional stability is developed. The corresponding schemes consist of one explicit difference schemes at the interface point and fully implicit schemes in the subdomains. The stability and error estimates of the schemes are derived. Finally, the numerical experiment is presented which confirm the results and conclusions. Related Articles | Metrics

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Asymptotics for the LASSO estimator for partially linear models LI Feng1, LU Yi-qiang2 J4    2012, 47 (3): 93-97.   Abstract （1694）      PDF（pc） （908KB）（3782）       Save  Based on the profile least squares method, the LASSO penalty profile least squares estimator is constructed, and the choices of penalty parameter and bandwidth are also discussed. Because the optimization problem is linear, it can be easily implemented. Under some regular conditions, the consistency and asymptotic normality of the estimator for parameter component are investigated. Finally, Monte Carlo simulation studies are conducted to assess the finite sample performance of the proposed variable selection procedures. Related Articles | Metrics

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Research on self-supervised pre-training for recommender systems Jiyuan YANG,Muyang MA,Pengjie REN,Zhumin CHEN,Zhaochun REN,Xin XIN,Fei CAI,Jun MA JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2024, 59 (7): 1-26.   DOI: 10.6040/j.issn.1671-9352.1.2023.043 Abstract （836）   HTML （5）    PDF（pc） （7266KB）（3772）       Save Plenty of recent studies explores the application of pre-training techniques within the context of recommendation scenarios and the design of pre-training tasks in order to enhance the overall performance of recommendation. This paper extensively reviews the progress in research of recommendation models based on pre-training, classifies and compares different pre-training methods, and conducts extensive experiments and analyses on some representative models using three benchmark datasets for recommendation systems. The datasets and codes have been made open source. Finally, we summarize and prospect the future development trend of recommendation models based on pre-training. Table and Figures | Reference | Related Articles | Metrics

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Ambidextrous innovation of brand community members' resource endowment Wen-yuan MA,Qiu-tong LI,Yao-yao ZHANG,Jin ZHU JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2020, 55 (1): 77-85.   DOI: 10.6040/j.issn.1671-9352.0.2019.596 Abstract （1593）   HTML （9）    PDF（pc） （1008KB）（3766）       Save Based on the ability-motivation-opportunity (AMO) theory, the mechanism of ambidextrous innovation motivation of brand community members were studied using structural equation modeling. The moderating role of community commitment to the innovation processes was explored. It was found that (1) brand knowledge positively influences the exploitative innovation, while social capital has a positive impact on exploratory innovation; (2) the community innovation opportunity partially mediates the negative influence of members' brand knowledge on exploitative innovation and positive influences of members' social capital on exploratory innovation; (3)member's community commitment negatively moderates the influence of community innovation opportunities to the exploitative innovation. Table and Figures | Reference | Related Articles | Metrics

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Progress in basic and technological research of enzyme system for lignocellulosics biodegradation QU Yin-bo JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2011, 46 (10): 160-170.   Abstract （1726）      PDF（pc） （875KB）（3667）       Save Research on cellulose biodegradation has been carried out for more than 50 years in Shandong University. Based on the mechanism studies on microbial degradation of lignocellulosics, a Penicillium decumbens strain, which can hydrolyze lignocellulose efficiently, was isolated from natural samples, and several catabolite repressionresistant mutants were obtained. Genome sequencing of the strains were carried out, and the composition of their enzyme system and the mechanism for regulation of enzyme synthesis were studied by systems biotechnological methods. The cellulase-overproducing mutants has been used for cellulase production in industrial scale, and for cellulosic ethanol production in biorefinery of corncobs. Related Articles | Metrics

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Extremal eigenvalues of a class of tridiagonal interval matrices JIAN Yuan, LIU Ding-you JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2015, 50 (12): 15-22.   DOI: 10.6040/j.issn.1671-9352.0.2014.549 Abstract （1619）      PDF（pc） （619KB）（3642）       Save A class of tridiagonal interval matrices is studied by the recursive characteristic polynomials and Chebyshev polynomials where some results on eigenvalues are involved. The sharp (lower and upper) bound for the eigenvalues of this class of tridiagonal interval matrices is presended, and the realization matrices whose smallest (largest) eigenvalues reach the lower(upper) bound is characterized. Reference | Related Articles | Metrics

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Semi-supervised classification based on the Markov random field and robust error function LIANG Jun1,2, CHEN Long2, ZHOU Wei-qi2, TAO Wen-qian1, YAO Ming2, XU Zheng-chuan3 J4    2010, 45 (11): 1-4.   Abstract （1898）      PDF（pc） （979KB）（3524）       Save A model of semi-supervised classification was proposed to overcome the problem induced by mislabeled samples. A decision rule was learned from labeled and unlabeled data,and a new energy function based on robust error function was used in the Markov random field. Also two algorithms based on the iterative condition mode and the Markov chain Monte Carlo were designed to infer the label of both labeled and unlabeled samples. Experimental results demonstrated that the proposed methods were efficient for a real-world dataset. Related Articles | Metrics

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Generalized interval-valued fuzzy rough sets and axiomatic characterizations ZHANG Hai-dong1, HE Yan-ping 2 J4    2013, 48 (09): 56-63.   Abstract （1066）      PDF（pc） （718KB）（3517）       Save A general framework is presented for the study of generalized interval-valued fuzzy rough sets integrating the rough set theory with the interval-valued fuzzy set theory by using constructive approach. Firstly, through employing an interval-valued fuzzy residual implicator and its dual operator, generalized upper and lower interval-valued fuzzy rough approximation operators with respect to an arbitrary interval-valued fuzzy approximation space are first defined. Based on properties of interval-valued fuzzy residual implicator on LI,  some interesting properties of interval-valued fuzzy rough approximation operators are then examined. In the axiomatic approach, interval-valued fuzzy rough approximation operators are further defined by axioms. And different axiom sets can characterize the essential properties of interval-valued fuzzy rough approximation operators. Related Articles | Metrics

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The quantitative analysis of the impact of financial news on stock market ZHAO Li-li, ZHAO Xi-qian, YANG Juan, WANG Tie-jun, LI Qing* J4    2012, 47 (7): 70-75.   Abstract （2097）      PDF（pc） （1192KB）（3462）       Save  Text mining and support vector regression techniques were adopted to quantify the impact of financial news on Chinese stock market. Then  the multiple regression of econometrics was used to analyze how the online financial news affected stock market returns systematically. It focused on the impact intensity and time of online news on the stock market, and its impact on listed firms with different scales. Experimental results show that firms with Shenzhen Stock Exchange are more affected by the Internetbased financial news than those of Shanghai Stock Exchange and firms with smaller size tend to have a stronger impact on the movements of Chinese stock market. Our findings include that Internet-based financial news contains hard-to-quantify information of firms, which investors incorporate into stock prices timely. Related Articles | Metrics

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Growth and physiological changes during plant senescence of ancient Pinus tabulaeformis Carr. WANG Qiao, ZHU Hong, WANG Hua-tian, MENG Xian-Peng,CAO Gui-ping, LI Jian, HUANG Chang-bao JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2016, 51 (5): 29-35.   DOI: 10.6040/j.issn.1671-9352.0.2015.265 Abstract （1597）      PDF（pc） （963KB）（3462）       Save In order to provide scientific basis of the vigor diagnosis and their rejuvenation and management to anti-aging, the growth and physiological diagnosis indices of the young healthy trees and senescence ancient pines were investigated. The annual pine needles from healthy and weak pines with different ages in the Taishan National Park were used as materials. The shoot length, needle length and coarseness, chlorophyll content, membrane permeability, net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs), intercellular CO2 concentration(Ci), mineral elements content of C, N, P, K and Mg, abscisic acid(ABA)content of pine needles were measured. The results showed that, comparing with healthy pines, the ancient ones had thinner, shorter needles and weaker photosynthetic capacity, lower growth of shoots, chlorophyll content and light use efficiency. Membrane permeability creased with membrane lipid peroxidation. There were no remarkable changes in P content and increased mineral elements content of C, 山 东 大 学 学 报 (理 学 版)第51卷 - 第5期王巧,等:油松古树衰老过程中的生长与生理变化 \=-N, Mg and K in senescing and weak ancient pines. Higher ABA content led to weakness of vigor. The correlation between morphological changes and physiological indexes were significant. It was summarized that growth and physiological indexes could be used as bases to diagnose the senescence and weakness of ancient pines. Reference | Related Articles | Metrics

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Measuring user influence of a microblog based on information diffusion GUO Hao, LU Yu-liang, WANG Yu, ZHANG Liang J4    2012, 47 (5): 78-83.   Abstract （1417）      PDF（pc） （832KB）（3457）       Save Information diffusion and influence modeling are hot topics in microblog research. To do research on influence quantitatively, a concept based on the message diffusion was introduced and complied with how to count it out. The proposed approach was validated on real world datasets, and the result of experiments shows that our method is both effective and stable, especially in condition of limited dataset and time span. Related Articles | Metrics

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Study on xylem structure and histochemistry in Aquilaria sinensis ZHANG Xing-li1,2,3, LIU Yang-yang2,4, CHEN Hong-jiang2,4, XU Yan-hong2, ZHANG Zheng2, YANG Yun2,4, WEI Jian-he 2, 4*, LIU Yu-jun1* J4    2012, 47 (7): 1-5.   Abstract （1712）      PDF（pc） （2738KB）（3452）       Save  To study the morphological and quantitative characteristics of the xylem and histochemistry of differentaged stems in Aquilaria sinensis, the anatomical structure of the stem was analyzed using the Jeffery method, histochemical staining, and microscopic observation. The results showed that the xylem was composed of 5 parts: pith, included phloem, xylem rays, vessels, and fiber tracheids. A transverse section showed that the included phloem (foraminate type) evenly distributed in the xylem. The xylem rays belonged to heterogeneous Ⅲ. The vessel pores were generally arranged as follows: radial pore clusters (2 to 4), multiple pores, pore chains (5 to 10), or a single pore; vestured pits were alternately arranged in the vessels′ lateral walls. Acclivitous simple vestured pits were present in the lateral walls of the fiber tracheid. Trabeculae were present in the neighboring fiber tracheids of the pith. Embolisms were present in the vessels and the fiber tracheids. Trabeculae and embolisms were firstly observed in A. sinensis. The levels and storage tissues of starch, reducing sugars, and volatile constituents were significantly different in the differentaged xylem. This study provides basic anatomical evidence for agarwood formation. Related Articles | Metrics

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Dimensionality reduction and retrieval algorithms for high dimensional data Wei SHAO,Gaoyu ZHU,Lei YU,Jiafeng GUO JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2024, 59 (7): 27-43.   DOI: 10.6040/j.issn.1671-9352.1.2023.062 Abstract （991）   HTML （12）    PDF（pc） （1007KB）（3376）       Save At present, most studies use some dimensionality reduction methods to convert high-dimensional vectors into low-dimensional vector representations, and then apply related vector retrieval optimization technology to achieve fast similarity retrieval, thereby improving the application performance of large models. Currently, there are many and scattered dimensionality reduction methods for high-dimensional data, and the dimensionality reduction methods used in different research backgrounds are different. Similarly, there are also many different retrieval ideas and optimization methods in vector retrieval technology. By reviewing the main ideas and optimization methods of recent dimensionality reduction and retrieval algorithms, this paper helps to generate inspiring connections between the two and support the development and in-depth research of subsequent high-dimensional vector retrieval optimization algorithms. Table and Figures | Reference | Related Articles | Metrics

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Schur factorization and normal matrices factorization of row (column) symmetric matrices YUAN Hun-ping J4    Abstract （2584）      PDF（pc） （186KB）（3347）       Save The concept of row (column) transposed matrix and row (column) symmetric matrix are given, and their basic properties are also studied. The formula for the Schur factorization and normal matrix factorization of row (column) symmetric matrix are obtained, which all can dramatically reduce the amount of calculation and Schur factorization and normal matrix factorization of row (column) symmetric matrix can save dramatically the CPU time and memory without losing any numerical precision. Related Articles | Metrics

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Chaos particle swarm optimization based on the adaptive inertia weight ZHOU Yan1,2, LIU Pei-yu 1,2, ZHAO Jing1,2, WANG Qian-long1,2 J4    2012, 47 (3): 27-32.   Abstract （1834）      PDF（pc） （1570KB）（3338）       Save Aiming at the premature convergence problem which the particle swarm optimization algorithm suffers from, a chaos particle swarm optimization based on adaptive inertia weight is proposed. Firstly, chaotic sequence generated by cube map is used to initiate individual position, which strengthens the diversity of global searching. Secondly, adaptive inertia weight is adopted to improve the convergence rate. Furthermore, chaos perturbation is utilized to avoid the premature convergence. The results of the simulation experiment show that the convergence rate and the precision of the improved algorithm are obviously enhanced, and the algorithm can effectively avoid the premature convergence problem. Related Articles | Metrics

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HPLC separation of enantiomers of dracocephins A LI Chao, ZHAO Li-juan, ZHANG Yao, REN Dong-mei* JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2014, 49 (1): 36-38.   DOI: 10.6040/j.issn.1671-9352.0.2013.419 Abstract （1667）      PDF（pc） （1255KB）（3305）       Save To establish a direct enantioseparation method by HPLC on immobilized amylose-based chiral stationary phase for the chiral separation of the enantiomers of dracocephins A. The separation was carried out using a Chiralpak IA column (4.6mm×250mm, 5μm) in combination with n-hexane-ethyl acetate (10∶90) as mobile phase. The flow rate was 1.0mL·min-1 and detection wavelength was 290nm, whilst the column temperature was room temperature. The established chromatographic method was effective for the simultaneous separation of the two pairs of enantiomers of dracocephins A. The elution order was determined by coupling HPLC-CD detection and comparison with each single enantiomer. Immobilized amylosebased chiral stationary phase is suitable for the enantioseparation of dracocephins A. Related Articles | Metrics

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Population characteristics and seasonal variations of  phytoplankton in Nansi Lake LIU Qian-hui1, PEI Hai-yan1, 2,*, HU Wen-rong1,2, XIE Jun3 J4    2010, 45 (5): 12-18.   Abstract （1651）      PDF（pc） （1037KB）（3291）       Save Phytoplankton are an important biological indicator for water quality assessment. To investigate the water quality of Nansi Lake, the population composition, quantity and dominant species of phytoplankton were studied from June 2008 to May 2009. 8 phyla, 59 genera and 117 species have been identified from 5 monitoring stations based on a monthly sampling. The species numbers of Chlorophyta and Bacillariophyta accounted for the total species number were 48.7％ and 23.9％, respectively. There were many more species in summer and autumn than that in winter and spring. The seasonal variations of phytoplankton density were the same as that of species number. The predominant indices were not high, ranging from 0.04 to 0.35, and there were 23 predominant species including Chlorella vulgaris, Scenedesmus dimorphus and  Aulacoseira granulata. The phytoplankton diversity and evenness indices varied from 1.56 to 2.36, and 0.59 to 0.84, respectively. It could be concluded that the phytoplankton population structure in Nansi Lake is complex, and the stability of the phytoplankton population composition and quantitative distribution showed a high degree in Nansi Lake. The phytoplankton population characteristics changed significantly compared with the data in 1980s.   Related Articles | Metrics

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An Upper Bound on the Sum of the k Largest Eigenvalues of  the Signless Laplacian Matrix of a Graph JIN Guang-qing, ZUO Lian-cui* J4    2013, 48 (8): 1-4.   Abstract （1718）      PDF（pc） （671KB）（3253）       Save The sum of the k largest eigenvalues of the signless Laplacian matrix of a simple connected graph is studied and an upper bound is obtained in terms of the degree sequence and the order of the graph. Related Articles | Metrics

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Security analysis of fast public key cryptosystem on matrix ring GU Chun-sheng1,2, WU Fang-sheng2, JING Zheng-jun2,3, YU Zhi-min2 J4    2013, 48 (09): 22-28.   Abstract （1239）      PDF（pc） （750KB）（3187）       Save It is very important to analyze the security of fast public key cryptosystem suitable for computing devices with limited resources. By applying lattice reduction algorithm, it is not more difficult than the integer factorization problem to break the fast public key cryptosystem based on matrix ring. That is, given an oracle of factoring integers, there exists a polynomial time algorithm which solves the secret key from the public key. The correctness of security analysis is demonstrated by computational experiments. Related Articles | Metrics

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Short text classification based on word embedding similarity MA Cheng-long, JIANG Ya-song, LI Yan-ling, ZHANG Yan, YAN Yong-hong JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2014, 49 (12): 18-22.   DOI: 10.6040/j.issn.1671-9352.3.2014.295 Abstract （1832）      PDF（pc） （2161KB）（3183）       Save As the short length of the Web short text and less shared words, a lot of out of vocabulary (OOV) words would appear, and these words make the task of text classification more difficult. To solve this problem, a new general framework based on word embedding similarity was proposed. First, get the word embedding file with unsupervised learning method based on unlabeled data. Second, extend the OOVs with the similar words in training data through computing the similarities of different word embeddings. The comparison with the baseline system shows that the proposed method gets better 1%-2% rate and outperforms more 10% rate on small training data set. Reference | Related Articles | Metrics