Top Read Articles

    Published in last 1 year |  In last 2 years |  In last 3 years |  All
    Please wait a minute...
    Ionic liquid gels
    Juan GAO,Xiao-lin WANG,Heinz HOFFMANN,Jing-cheng HAO
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2019, 54 (1): 1-18.   DOI: 10.6040/j.issn.1671-9352.9.2018
    Abstract1714)   HTML69)    PDF(pc) (20377KB)(424)       Save

    Ionic liquid gels (Ionogels) are the kind of gels formed by using ionic liquids as dispersing media. As new mixed materials, ionogels not only keep the original properties of ionic liquids, but also solve the problems of ionic liquid spillover. The high plasticity in shape meets the needs of special materials and expands the application of ionic liquids. There are many kinds of ionogels, which can be divided into physical and chemical types. Recent years, the structures, properties and applications of ionogels have become one of the hot topics in colloid and interface sciences, as well as the main contents of soft matters. The progress in the construction, structures, properties and applications of ionogels in recent years is reviewed and summarized, which can provide an important theoretical guidance for the construction and applications of ionogels in the future.

    Table and Figures | Reference | Related Articles | Metrics
    Composition and structure on attribute reduction of interval-set concept lattices
    ZHANG En-sheng
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 17-24.   DOI: 10.6040/j.issn.1671-9352.4.2018.052
    Abstract1572)      PDF(pc) (491KB)(407)       Save
    Interval-set provides a research tool for processing partially known concepts and for approximating undefinable or complex concepts. Concept lattices is a powerful tool for data analysis in machine learning, data mining, knowledge discovery, information retrieval, and so on. Interval-set concept lattices is the product of the combination concept lattices and the interval-set theory,which is a powerful tool for data analysis in machine learning, data mining, knowledge discovery and information retrieval on the information systems of partially known concepts or undefinable concepts. The attribute reduction of interval-set concept lattices is a kind of the method which reveals the elementary character of interval-set concept lattices attribute. This paper reveals the composition and structure of the attribute reduction of interval-set concept lattices. The equivalence relative necessary attributes are not in the same attribute reduction; and the intersection of attribute reduction and any relative necessary attribute equivalence class is nonempty. The set of the core attributes and the relative necessary attributes chosen by taking an attribute from each relative necessary attribute equivalence class must be an attribute reduction.
    Reference | Related Articles | Metrics
    BERT-IDCNN-CRF for named entity recognition in Chinese
    Ni LI,Huan-mei GUAN,Piao YANG,Wen-yong DONG
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2020, 55 (1): 102-109.   DOI: 10.6040/j.issn.1671-9352.2.2019.076
    Abstract1477)   HTML42)    PDF(pc) (2001KB)(349)       Save

    The pre-trained language model, BERT (bidirectional encoder representations from transformers), has shown promising result in NER (named entity recognition) due to its ability to represent rich syntactic, grammatical information in sentences and the polysemy of words. However, most existing BERT fine-tuning based models need to update lots of model parameters, facing with expensive time cost at both training and testing phases. To handle this problem, this work presents a novel BERT based language model for Chinese NER, named BERT-IDCNN-CRF (BERT-iterated dilated convolutional neural network-conditional random field). The proposed model utilizes traditional BERT model to obtain the context representation of the word as the input of IDCNN-CRF. At training phase, the model parameters of BERT in the proposed model remain unchanged so that the proposed model can reduce parameters training while maintaining polysemy of words. Experimental results show that the proposed model obtains significant training time with acceptable test error.

    Table and Figures | Reference | Related Articles | Metrics
    Dynamic discovery of authors research interest based on the combined topic evolutional model
    YU Chuan-ming, ZUO Yu-heng, GUO Ya-jing, AN Lu
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 23-34.   DOI: 10.6040/j.issn.1671-9352.1.2017.044
    Abstract1451)      PDF(pc) (4162KB)(349)       Save
    We propose a new combined topic model, i.e. author topic time-latent dirichlet allocation(ATT-LDA)with author ranking(AR), for the of dynamic discovery of researchers' interest, which is based on the academic literature in the financial field. Through the proposed model, we can easily acquire the probability distribution of the authors' interest, as well as the probability distribution of topics on deferent words. The influence of the ranking in the co-author list are fully taken into consideration. The empirical study shows that the proposed method can effectively reveal the dynamic change of interest of the authors in the financial field.
    Reference | Related Articles | Metrics
    Design and implementation of topic detection in Russian news based on ontology
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 49-54.   DOI: 10.6040/j.issn.1671-9352.0.2017.650
    Abstract1363)      PDF(pc) (661KB)(238)       Save
    Aiming at the problem of topic detection in Russian news, using automatic morphological analysis and named entity recognition as the auxiliary means, a method for describing Russian news elements and calculating their similarities based on ontology was designed. The Single-pass algorithm was used to carry out text clustering experiments for topic detection. By comparing the results of vector space model(VSM)model and ontology model, it is proved that the latter has relatively high accuracy and validity.
    Reference | Related Articles | Metrics
    Research on supply chain decision making of equitable retailers with fair sensitivities
    ZHANG Ke-yong, LI Jiang-xin, YAO Jian-ming, LI Chun-xia
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 83-94.   DOI: 10.6040/j.issn.1671-9352.0.2018.032
    Abstract1347)      PDF(pc) (1177KB)(322)       Save
    In order to study the influence of heterogeneity of subject of fair preference on the decision of supply chain, fair sensitivity was introduced to the decision model of fair preference decision-maker. We build a secondary supply chain consisting of a manufacturer, two competing retailers, one of which has a fair preference and fair sensitivity. Based on the social comparison theory, a supply chain decision model with horizontal equity preference and vertical equity preference was established, and the influence of fair sensitivity coefficient on decision variables and utility of decision makers was obtained. Finally, numerical examples were used to verify the conclusion. The results show that the existence of fair preference and fair sensitivity does not increase the utility value of retailer itself, and it increases the competition between the two retailers under the horizontal equity preference. In the adverse unfair situation, the utility of the retailer increases with the increase of the fair sensitivity coefficient, and decreases with the increase of the fair sensitivity coefficient in the favorable unfair situation. Therefore, in the case of unfair adverse circumstances, the retailer should remain humble inferiority, and should not overestimate his own abilities and status. But in the case of favorable unfair circumstances, the retailer should be confident. Only in this way can he keep the utility maximization.
    Reference | Related Articles | Metrics
    Differential privacy partitioning algorithm based on adaptive density grids
    YAN Yan, HAO Xiao-hong
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 12-22.   DOI: 10.6040/j.issn.1671-9352.0.2017.418
    Abstract1322)      PDF(pc) (1990KB)(295)       Save
    In order to balance the influence of noise error and uniform hypothesis error for the two-dimensional partitioning publishing, a new hierarchical differential privacy partitioning algorithm DP-ADG is proposed. Firstly, the position space is clustered to form the density adaptive grids in the first layer. Then in the second layer, different partitioning methods are adopted for different density blocks. The noise error introduced by a large number of null nodes is avoided while reducing the uniform hypothesis error. While using the hierarchical partitioning strategy, different Laplace noise of different privacy budgets is added to the results of two phases according to the sequential composition of differential privacy, in order to realize the overall ε differential privacy protection for the publishing data. Experimental results show that the algorithm has good effect on improving the accuracy of range counting query, saving unnecessary spatial decomposition process, as well as improving the efficiency of the algorithm.
    Reference | Related Articles | Metrics
    Reader emotion classification with news and comments
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 35-39.   DOI: 10.6040/j.issn.1671-9352.1.2017.003
    Abstract1321)      PDF(pc) (573KB)(191)       Save
    The news and comments are important resources to classify the reader emotion. However, previous studies only used news texts or mixed two types of texts as a general feature, which did not make the best use of the differences and connections between different textual features. Based on it, the paper proposed a new approach named dual-channel LSTM, which treated two types of texts as different features. First, the approach learned a LSTM representation with a LSTM recurrent neural network. Then, it proposed a joint learning method to learn the relationship between the features. Empirical studies demonstrate the effectiveness of the proposed approach to reader emotion classification.
    Reference | Related Articles | Metrics
    Attribute reduction of incomplete contexts based on similarity relations
    LI Tong-jun, HUANG Jia-wen, WU Wei-zhi
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 9-16.   DOI: 10.6040/j.issn.1671-9352.4.2018.100
    Abstract1319)      PDF(pc) (450KB)(270)       Save
    The paper focuses on the attribute reduction of incomplete contexts. First, by comparing the values of the objects on each of the attributes, one kind of similarity relations is proposed in incomplete contexts, based on which decision rules with clear meaning can be revealed via rough approximation operators. Subsequently, one type of attribute reduction of incomplete contexts is defined, under which the similarity relations keep unchanged, some judgment theorems are given for attribute reduction, and different types of attributes for attribute reduction are characterized by the similarity relations. At last, by constructing a Boolean function with discernibility attributes among objects, an approach for attribute reduction is obtained, and an illustration example is taken to show the reliability of approach.
    Reference | Related Articles | Metrics
    Extraction of Chinese multiword expressions based on Web text
    GONG Shuang-shuang, CHEN Yu-feng, XU Jin-an, ZHANG Yu-jie
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 40-48.   DOI: 10.6040/j.issn.1671-9352.1.2017.060
    Abstract1318)      PDF(pc) (645KB)(253)       Save
    A Multiword Expression is a kind of fixed and semi-fixed collocation in natural language, especially in network text, MWEs appear frequently, which brings a great challenge to the subsequent segmentation and text comprehension. Therefore, we propose a double-layer extraction strategy to achieve the recognition of MWEs in this paper. In the first layer, we use the LRE+EMI algorithm to achieve the initial extraction of MWEs; In the second layer, we use SVM classifier and construct the characteristics of context and word vector to classify the MWEs and non-MWEs, in order to further filter the MWEs candidate list on the basis of the MWEs candidate list got from the first layer. After the experiment, the F value of MWEs reached 84.92% in the first layer and the F value of MWEs reached 89.58% in the second layer, which have greatly improved performance compared with the baseline system. The experimental result shows that the double-layer extraction strategy can availably extract MWEs, and can effectively improve the segmentation results.
    Reference | Related Articles | Metrics
    Anomaly detection model of host group based on graph-evolution events
    YE Xiao-ming, CHEN Xing-shu, YANG Li, WANG Wen-xian, ZHU Yi, SHAO Guo-lin, LIANG Gang
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 1-11.   DOI: 10.6040/j.issn.1671-9352.2.2017.169
    Abstract1309)      PDF(pc) (5937KB)(588)       Save
    Aiming at the communication behavior based on service aggregation and the new collaborative attack mode that is typical of distributed attack in the network environment, the anomaly detection model of host group based on graph-evolution events is proposed. It analyzes the potential socialization of actors, the clustering of host clusters and the dynamics of their group behavior. The model has the characteristics of no parameters and extensible data magnitude. The dynamic evolution events and detection algorithms are defined and proposed to detect abnormal host groups. The model is implemented and deployed on Spark, and the data from the actual computer and network environment is analyzed and verified. The experimental results show that this model can effectively describe group behavior, expose important graph-evolution events, and locate the host group with abnormal occurrence accurately. The detection rate of group members is 95.09%.
    Reference | Related Articles | Metrics
    Local optimal granularity selections in generalized multi-scale decision systems
    GU Shen-ming, LU Jin-lu, WU Wei-zhi, ZHUANG Yu-bin
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 1-8.   DOI: 10.6040/j.issn.1671-9352.4.2018.184
    Abstract1309)      PDF(pc) (489KB)(849)       Save
    People tend to choose the appropriate level of granularity to solve problems in application. In the classical multi-scale decision systems, during the process of constructing the levels of granularity, some fixed levels of granularity are selected manually for attribute values. Aiming at generalized multi-scale decision systems in this paper, the levels of granularity are constructed by using the scale combination of attribute values. Furthermore, the selection problems of local optimal granularity are studied. The concept of generalized multi-scale decision systems is introduced firstly. Then, notions of the optimal granularity and the local optimal granularity in consistent generalized multi-scale decision system are defined, and the algorithms for finding optimal granularities and the local optimal granularities are described. Finally, the generalized decisions are introduced to inconsistent generalized multi-granular decision systems, the generalized optimal granularity and the generalized local optimal granularity are defined, and the algorithms for finding the generalized optimal granularity and the generalized local optimal granularity are also investigated.
    Reference | Related Articles | Metrics
    Block discernibility matrix based on decision classification and its algorithm finding the core
    ZUO Zhi-cui, ZHANG Xian-yong, MO Zhi-wen, FENG Lin
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 25-33.   DOI: 10.6040/j.issn.1671-9352.4.2018.121
    Abstract1260)      PDF(pc) (590KB)(206)       Save
    Attribute reduction is the fundamental approach of rough set theory to implement data mining, and its relevant algorithms are mainly based on the core. For the core, both its representation of the discernibility matrix and its calculation for finding the core exhibit important significance, but the existing discernibility matrix and its core algorithm have time and space limitations. According to the sparsity and large scale of the discernibility matrix, the block discernibility matrix based on the decision classification and its algorithm finding the core are proposed, and thus the decision classification information is directly applied to the form structure and problem solving. At first, the block discernibility matrix is defined by the decision classification, and its calculation algorithm is achieved. Then, based on the block discernibility matrix, the essence and algorithm of the core are provided. Finally, the proposed methods effectiveness is verified by the example and experiment. The block discernibility matrix based on the decision classification effectively implements the information extraction and dimensionality reduction, so its relevant algorithm finding the core well decreases the time and space complexities of the corresponding algorithm based on the discernibility matrix.
    Reference | Related Articles | Metrics
    Equilibrium decisions of a two-layer supply chain network considering retailers horizontal fairness
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 69-82.   DOI: 10.6040/j.issn.1671-9352.0.2018.033
    Abstract1211)      PDF(pc) (904KB)(211)       Save
    We extended the vertical fairness research on a supply chain with one manufacturer and one retailer, and considered the horizontal fairness preference in a two-layer supply chain network consisted by an upper tier for a single manufacturer and a lower tier for multiple retailers and demand markets. The retailer chooses his decision based on the horizontal fairness preference comparing the profit of other retailers. Considering retailers horizontal fairness preference, the Nash game model of the retailers and the Stackelberg-Nash game model of the two-layer supply chain network were constructed. The optimal decisions of a two-layer supply chain network were obtained by the penalty function algorithm. The numerical results show that the horizontal fairness preference among retailers lead to different changes in the decisions of the supply chain members, and the maximum profit of manufacturer and the maximum utility of retailers are lower than those of neutral retailers. Finally, some advices are provided to the supply chain members to deal with the horizontal fairness preference.
    Reference | Related Articles | Metrics
    Decomposition for L2(Rn)by subspaces composed of high-dimensional tight framelet packets
    GAI Xiao-hua, GUO Xue-jun, FENG Jin-shun, CHEN Qing-jiang, CHENG Zheng-xing
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 34-42.   DOI: 10.6040/j.issn.1671-9352.0.2018.058
    Abstract1202)      PDF(pc) (454KB)(243)       Save
    The decomposition for space L2(Rn)by subspaces composed of framelet packets are investigated. The characteristics of the high-dimensional wavelet frame packets with a quantity dilation matrix are described by using time-frequency analysis method and functional analysis method. The subspaces from the high-dimensional framelet packets are constructed. Moreover the direct decomposition for space L2(Rn)is obtained from these subspaces composed of framelet packets. The frequency-field formulas for the high-dimensional framelet packets are presented. A sufficient condition is suggested that a Parseval frame constituted from the high-dimensional tight framelet packets of space L2(Rn). These enrich the wavelet frame theory, so that they can be applied to a wider range.
    Reference | Related Articles | Metrics
    Some notes on E2-term of Adams spectral sequence
    LIU Yan-fang, WANG Yu-yu
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 43-48.   DOI: 10.6040/j.issn.1671-9352.0.2017.383
    Abstract1199)      PDF(pc) (358KB)(283)       Save
    The E2-term of the Adams spectral sequence, which is the cohomology of mod p Steenrod algebra A, will be discussed by using the May spectral sequence. In the Adams spectral sequence, the non-triviality of (~overγ)s+3b1hn is given, and it doesnt be hitted by any element. These results are important for the detection of new family of elements in the stable homotopy groups of spheres.
    Reference | Related Articles | Metrics
    Comparison principles for viscosity solution of fully nonlinear parabolic equations with superlinear gradient nonlinearities
    WANG Jun-fang, ZHAO Pei-hao
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 77-83.   DOI: 10.6040/j.issn.1671-9352.0.2017.341
    Abstract1194)      PDF(pc) (399KB)(198)       Save
    A problem of fully nonlinear degenerate parabolic partial differential equations with a superlinear gradient nonlinearity is studied. A comparison result is proved between semicontinuous viscosity subsolutions and supersolutions having superlinear growth. We extend our result to monotone systems of parabolic equations.
    Reference | Related Articles | Metrics
    Design and approximation of SISO three layers feedforward neural network based on Bernstein polynomials
    XIAO Wei-ming, WANG Gui-jun
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 55-61.   DOI: 10.6040/j.issn.1671-9352.0.2017.606
    Abstract1192)      PDF(pc) (627KB)(202)       Save
    A single input single output(SISO)three layers feedforward neural network was designed by using the difference value between adjacent equidistant subdivision points of unary Bernstein polynomial with a Sigmodial transfer function, and a method of selecting the connection weights and thresholds was given. In addition, according to the approximation theorem for unary Bernstein polynomial, we proved that SISO three layers feedforward neural network could also approximate a continuous function. The analytical expression of the neural network was obtained by an example.
    Reference | Related Articles | Metrics
    Quantum secret sharing scheme realizing all hyperstar quantum access structure
    JIAO Hong-ru, QIN Jing
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (9): 62-68.   DOI: 10.6040/j.issn.1671-9352.0.2017.569
    Abstract1188)      PDF(pc) (423KB)(191)       Save
    To realise more quantum access structure, we put forward a new quantum secret sharing scheme by sharing non-objected secret sharing states to some authorised subsets in the hyperstar quantum access structure. Compared with other similar sechems, all partners in our scheme obtain quantum share and our scheme possess unconditional security.
    Reference | Related Articles | Metrics
    Vertex-distinguishing IE-total coloring and general-total coloring of K1,3,p and K1,4,p
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 53-60.   DOI: 10.6040/j.issn.1671-9352.0.2017.240
    Abstract1165)      PDF(pc) (403KB)(167)       Save
    The vertex-distinguishing IE-total coloring and vertex-distinguishing general total coloring of complete tripartite graphs K1,3,p and K1,4,pare discussed by distributing the color sets in advance,constructing the colorings and proving by contradiction. The vertex-distinguishing IE-total chromatic number and vertex-distinguishing general total chromatic number of K1,3,p and K1,4,p have been determined.
    Reference | Related Articles | Metrics
    Order of matching energy and Hosoya index of Q-shape graphs
    LIU Xiao-hua, MA Hai-cheng
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 61-65.   DOI: 10.6040/j.issn.1671-9352.0.2017.280
    Abstract1156)      PDF(pc) (336KB)(151)       Save
    The Q(s,t)(s≥2t≥1)is the graph with s+t+1 vertices. A complete order of matching energy of the Q-shape graphs is given. As a consequence,the order of Hosoya index also be obtained.
    Reference | Related Articles | Metrics
    Inverse spectral problem of Jacobi matrices and its application
    YU Qian-qian, WEI Guang-sheng
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 66-76.   DOI: 10.6040/j.issn.1671-9352.0.2018.109
    Abstract1150)      PDF(pc) (455KB)(241)       Save
    The inverse spectral problem of Jacobi matrices is considered. A new inverse spectral theorem for Jacobi matrices with some rank 1 perturbations of the matrix Jn is proved. And the theorem is applied to the corresponding mass-spring system. The necessary and sufficient conditions for the existence and uniqueness of the solution are derived. Furthermore, the numerical algorithm and some numerical examples are given.
    Reference | Related Articles | Metrics
    Metric model for cloud computing security risk assessment
    RUAN Shu-hua, WENG Jun-hao, MAO Hui, CHEN Xue-lian
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (3): 71-76.   DOI: 10.6040/j.issn.1671-9352.2.2017.380
    Abstract1145)      PDF(pc) (723KB)(290)       Save
    From three aspects related to cloud computing of policies, management and technologies, an indicator system of cloud security risk assessment is established for the security risk assessment problem in cloud computing environment. A metric model of security risk in cloud computing environment is established by fusing Delphi method, fuzzy analytical hierarchy process and fuzzy comprehensive evaluation method. Measurement results of risk instances show that the metric model could provide effective quantitative evaluation for the security risk assessment in cloud computing environment.
    Reference | Related Articles | Metrics
    On homological classification of weakly torsion free Rees factor S-posets
    QIAO Hu-sheng, SHI Xue-qin
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 49-52.   DOI: 10.6040/j.issn.1671-9352.0.2018.004
    Abstract1138)      PDF(pc) (298KB)(214)       Save
    The characterization of pomonoids over which all weakly torsion free Rees factor S-posets have some kind of flatness is given, and the homological classification problem of weakly torsion free Rees factor S-posets are obtained. As applications, the homological classification of torsion free and po-torsion free Rees factor S-posets are got.
    Reference | Related Articles | Metrics
    Existence of periodic solutions of a class of third order delay differential equations in Banach spaces
    CHEN Yu-jia, YANG He
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (8): 84-94.   DOI: 10.6040/j.issn.1671-9352.0.2017.582
    Abstract1094)      PDF(pc) (510KB)(330)       Save
    Applying the monotone iterative method of upper and lower solutions, we discuss the existence of 2π-periodic solutions for the third-order differential equation with delays in ordered Banach space Eu(t)+M0u(t-τ0)=f(t,u(t), u(t-τ1), u(t-τ2)), t∈R,where f:R×E3→E is a continuous function which is 2π-periodic in t, and τ012 are positive constants. By establishing a new maximum principle, a monotone iterative procedure for the equation is constructed. Some existence and uniqueness results of 2π-periodic solutions for this equation are obtained.
    Reference | Related Articles | Metrics
    Semilattice-ordered completely regular periodic semigroups
    SHAO Yong
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 1-5.   DOI: 10.6040/j.issn.1671-9352.0.2017.506
    Abstract1008)      PDF(pc) (315KB)(347)       Save
    It is proved that the multiplicative reducts of semilattice-ordered completely regular periodic semigroups are regular orthocryptogroups through the research of semilattice-ordered completely regular periodic semigroups. Semilattice-ordered completely regular periodic semigroups are equivalent characterizations of semilattice-ordered regular band and distributive lattices are obtained by using partial orders.
    Reference | Related Articles | Metrics
    Privacy preservation for location-based services
    Hai-yan KANG,Wan-xiang ZHU
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (11): 35-50.   DOI: 10.6040/j.issn.1671-9352.0.2018.128
    Abstract944)   HTML27)    PDF(pc) (1792KB)(559)       Save

    The disclosure of privacy involves not only the users' locations and queries data, but also the users' identities, interests, social habits, behavior patterns and privacy hidden in these data. A review of privacy preserving for location-based services (LBS) is provided. The application scenarios of location services is introduced, the method of location privacy attack is given. The existing research on the privacy protection system structure and protection technology is summarized. Finally, future research is prospected, and a cache-based spatiotemporal disturbance method and LBS privacy protection metric hypothesis scheme are proposed.

    Table and Figures | Reference | Related Articles | Metrics
    Judgement of Weyls theorem for bounded linear operators
    ZHANG Ying, CAO Xiao-hong, DAI Lei
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 82-87.   DOI: 10.6040/j.issn.1671-9352.0.2018.134
    Abstract937)      PDF(pc) (374KB)(198)       Save
    Let H be an infinite dimensional separable complex Hilbert space and B(H) be the algebra of all bounded linear operators on H. T∈B(H) satisfies Weyls theorem if σ(T)\σw(T)=π00(T), where σ(T) and σw(T) denote the spectrum and the Weyl spectrum respectively, π00(T)={λ∈iso σ(T):0<n(T-λI)<∞}. An operator T∈B(H) is said to have the single-valued extension property, if for every open set U⊆C, the only analytic solution of the equation (T-λI)f(λ)=0(for all λ∈U)is zero function on U. Using the single-valued extension property, we give a new judgement for Weyls theorem.
    Reference | Related Articles | Metrics
    Characterization of monoids by C(P')acts
    LIANG Xing-liang, WU Su-peng, REN Jun
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 9-13.   DOI: 10.6040/j.issn.1671-9352.0.2017.512
    Abstract931)      PDF(pc) (343KB)(305)       Save
    Let S be a monoid. By using ring theory and module theory, C(P')right S-acts in the category of S-acts are introduced, and some important monoids, such as P(P')monoids, periodic monoids and so on, are characterized by C(P')property of S-acts. Further, some important results on C(P)right S-acts are extended. Meanwhile, an important significance to the application of regularity in S-acts is presented.
    Reference | Related Articles | Metrics
    Preinvexity of n-dimensional fuzzy number-valued functions
    GONG Zeng-tai, GAO Han
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 72-81.   DOI: 10.6040/j.issn.1671-9352.0.2017.631
    Abstract924)      PDF(pc) (486KB)(194)       Save
    By means of the partial order relation in n-dimensional fuzzy number space, some preinvexity of n-dimensional fuzzy number-valued functions are defined, including preinvexity, weakly preinvexity, strictly preinvexity, weakly strictly preinvexity, prequasiinvexity, weakly prequasiinvexity, strictly prequasiinvexity, weakly strictly prequasiinvexity, and so on. In addition, their interrelation of the preinvexity of n-dimensional fuzzy number-valued functions are discussed, and some examples are given to illustrate the interrelation of the preinvexity.
    Reference | Related Articles | Metrics
    A survey of visual saliency and salient object detection methods
    Jia XU,Peng JIANG
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2019, 54 (3): 28-37.   DOI: 10.6040/j.issn.1671-9352.0.2018.601
    Abstract922)   HTML17)    PDF(pc) (7152KB)(138)       Save

    Saliency detection aims to locate the most attractive areas in image or video data, as the basic task of computer vision field, has receive intensive attentions. Many methods have been proposed recently, these methods usually can be classified into two branches: visual saliency detection and salient object detection. Tough the methods of two branches usually share the similar features and even the frameworks, their performances on datasets of different branch have large gap, seldom works have compared and analyzed them. In this work, we will provide a detailed review and analysis of main works in two branches, including their mechanism, metrics and datasets. Besides, in this work, we summarized approaches to boost visual saliency detection methods for the task of salient object detection. With these approaches, visual saliency detection methods can be applied to detect the salient object and show superior performance that even outperform some specialized state-of-the-art salient object detection methods, thus reduce the performance inconsistence in different specialized datasets.

    Table and Figures | Reference | Related Articles | Metrics
    Fusion of pointwise and deep learning methods for passage ranking
    PANG Bo, LIU Yuan-chao
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (3): 30-35.   DOI: 10.6040/j.issn.1671-9352.1.2017.012
    Abstract919)      PDF(pc) (914KB)(253)       Save
    Intelligent question answering is an important way to make information acquisition more intelligent and convenient. Intelligent Q&A oriented passage ranking is very important for accurately grasping the user's query intention, improving the user experience and the accuracy of feedback. We use deep learning techniques to capture semantic information about query and passages, and build the mapping model to the tag. Then the training model is used to predict the correlation between new query and the passage. Finally, we use the predicted correlation index of the passages and the query to sort the multiple answers of the same question. The experimental results show that our method can reach 3.979 on DCG@3 and 5.396 for DCG@5.
    Reference | Related Articles | Metrics
    Commutators of multilinear Calderón-Zygmund operator on Herz-type Hardy spaces with variable exponent
    ZHAO Huan, ZHOU Jiang
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 42-50.   DOI: 10.6040/j.issn.1671-9352.0.2017.567
    Abstract847)      PDF(pc) (397KB)(207)       Save
    Using the atomic decomposition theorem, we obtain the boundedness of a commutator generated by multilinear Calderón-Zygmund operator and BMO functions in Herz-type Hardy spaces with variable exponent. The proof is based on the boundedness of multilinear Calderón-Zygmund operator on variable exponent Lebesgue spaces.
    Reference | Related Articles | Metrics
    Graded version of Enochs theorem
    WU Xiao-ying, WANG Fang-gui
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 22-26.   DOI: 10.6040/j.issn.1671-9352.0.2018.147
    Abstract842)      PDF(pc) (405KB)(165)       Save
    It is shown that graded version of Enochs theorem is proved. Let B be a finitely generated graded R-module and let A be a graded submodule of B. If every graded homomorphsim f: A→E can be extended to B for any FP-gr-injective R-module E, then A is finitely generated. It follows that a finitely generated graded R-module M is finitely presented if and only if EXT1R(M,E)=0 for any FP-gr-injective module E.
    Reference | Related Articles | Metrics
    Lexical and semantic relevance matching based neural document ranking
    ZHANFG Fang-fang, CAO Xing-chao
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (3): 46-53.   DOI: 10.6040/j.issn.1671-9352.1.2017.001
    Abstract818)      PDF(pc) (758KB)(317)       Save
    A deep neural network based on lexical correlation matching and semantic correlation matching is proposed, which can be used to calculate the matching score of a query and a document in the information retrieval task. The lexical relevance matching model is based upon the word co-occurrence matrix of a query and a document, which takes the word matching information into consideration, so as to consider the position information of the matching word. The semantic relevance matching model is grounded in pre-trained word vector, then the convolution network extracts the semantic matching information between a query and different positions of the documents, where the final matching score is the superposition of the two sub-models. Model parameters are updated in the training process by maximizing the fractional difference between positive and negative samples. Experimental results indicate that the NDCG@3 and NDCG@5 of the model can attain to 0.790 4 and 0.818 3 respectively on the validation set. which significantly outperforms the baselines, verifying the importance of word and semantic matching for information retrieval.
    Reference | Related Articles | Metrics
    Improvement on the solution of pressure equation based on alternating direction in chemical flooding model
    CAO Wei-dong, DAI Tao, YU Jin-biao, WANG Xiao-hong, SHI An-feng
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 88-94.   DOI: 10.6040/j.issn.1671-9352.0.2018.103
    Abstract814)      PDF(pc) (626KB)(213)       Save
    Based on the general chemical flooding mathematical model for numerical simulation at home and abroad, an improved alternating direction iterative algorithm for solving phase pressure equation is proposed. An alternating direction iterative scheme for three dimensional parabolic equations is constructed, and a new calculation method for the iterative parameters is proposed with the second kind boundary condition and strong heterogeneous condition which is common in reservoir simulation model and practical geological model. The numerical algorithm is realized with SLCHEM, which is a simulation software of Shengli oilfield with independent intellectual property rights. Examples tests of actual field models show that the new structure of the alternating direction iterative algorithm improves the computational speed by more than 16% compared to the original preconditioned conjugate gradient algorithm, and the calculation accuracy could meet the application demand.
    Reference | Related Articles | Metrics
    Differential invariants and exact solutions of variable coefficients Benjamin-Bona-Mahony-Burgers equation
    LI Hui-hui, LIU Xi-qiang, XIN Xiang-peng
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 51-60.   DOI: 10.6040/j.issn.1671-9352.0.2017.607
    Abstract809)      PDF(pc) (1544KB)(222)       Save
    The Lie symmetry method is performed for the variable coefficients Benjamin-Bona-Mahony-Burgers(BBMB)equation and the continuous equivalence transformations are obtained. Starting with the equivalent algebra, the differential invariants of order one are constructed. It is found that there is no zero-order differential invariant for this equation, but there are eight first-order invariants that are independent of each other. Using the obtained first-order differential invariants, we make the group classification. Finally, the general variable coefficient BBMB equations are mapped to the constant coefficient BBM equation or Burgers equation or BBMB equation by the given equivalent transformation. And then a series of new exact solutions of those variable coefficient equations are obtained. The images of the exact solution of the special BBM equation with variable coefficients and Burgers equation of the exact solution are made.
    Reference | Related Articles | Metrics
    k-frugal list coloring of planar graphs without 4 and 5-cycles
    FANG Qi-ming, ZHANG Li
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 35-41.   DOI: 10.6040/j.issn.1671-9352.0.2017.648
    Abstract793)      PDF(pc) (603KB)(138)       Save
    For a graph G, c is a proper vertex coloring of G. If every color appears at most k-1 times in the neighbors of each vertex v, then c is called a k-frugal coloring of G. There are two conclusions on the k-frugal list coloring of planar graphs without 4 and 5-cycles:(1)For each planar graph without 4 and 5-cycles, if its maximum degree is Δ and Δ≥3k+8, then the k-frugal list chromatic number is less than or equal to 「(Δ)/(k-1)+2; (2)For each planar graph without 4 and 5-cycles, its k-frugal list chromatic number is no more than 「(Δ)/(k-1)+5.
    Reference | Related Articles | Metrics
    Text feature extraction method for sentiment analysis based on order-preserving submatrix and frequent sequential pattern mining
    CHEN Xin, XUE Yun, LU Xin, LI Wan-li, ZHAO Hong-ya, HU Xiao-hui
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (3): 36-45.   DOI: 10.6040/j.issn.1671-9352.1.2017.093
    Abstract790)      PDF(pc) (676KB)(219)       Save
    Feature extraction is one of the key steps in text sentiment analysis, which is also the main factor that affects the result. According to the variant expression of online review, the synonyms TF-IDF(term frequency-inverse document frequency)weight vector is obtained based on the semantic similarity. Then in view of the different length of online review, the local patterns of the feature vectors are identified with OPSM(order-preserving submatrix)biclustering algorithm. We improve PrefixSpan algorithm to detect the frequent classification phrase feature, which contain word order information. Furthermore some important factors, such as the separation of word, are also employed to improve the discriminative ability of sentiment orientation. Finally, the proposed method is applied to the sentiment analysis task experiment of the product reviews, and the results show that the text feature extraction has a better performance.
    Reference | Related Articles | Metrics
    The number of tilting modules over Gorenstein algebras
    CHEN Wen-qian, ZHANG Xiao-jin, ZAN Li-bo
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)    2018, 53 (10): 14-16.   DOI: 10.6040/j.issn.1671-9352.0.2017.654
    Abstract787)      PDF(pc) (297KB)(196)       Save
    For a Gorenstein algebra A, the number of tilting right A-modules is equal to the number of tilting left A-modules. A counter-example is given to show that for a Gorenstein algebra B with self-injective dimension no less than 2, the number of classical tilting left B-modules is not necessary to be equal to that of classical tilting right B-modules.
    Reference | Related Articles | Metrics