JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE)

An improved genetic algorithm in the application of Web spider

ZHANG Jing, XIAO Zhi-bin, RONG Hui, CUI Yi

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 1-6. doi:10.6040/j.issn.1671-9352.3.2014.155

Abstract ( 1437 )

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In order to further raise the information acquisition efficiency of Web spider in the Internet, IoT and industrial real-time control networks, an analysis of the causes that lead Web spider into the local optimum was presented. Meanwhile, the genetic algorithm (GA) for finding the global optimum was introduced in the application of Web spider. To avoid the slow convergence rate and premature convergence of the pure GA, an improved algorithm was proposed, which refined selection, crossover, and mutation of these three basic operators of GA. The experiment results show that this algorithm overcomes the above problems in combination with Web spider. Meanwhile, the recall ratio and retrieval precision are both increased.

Communication rate in the secret reconstruction phase

ZHANG Ben-hui, TANG Yuan-sheng, CHEN Wen-bing

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 7-11. doi:10.6040/j.issn.1671-9352.0.2014.379

Abstract ( 1503 )

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Communication rate is an extremely important concept in the field of secret sharing. It was proved that the communication rate ρ=v/((v+t-l)l) of the ideal (t,n)-threshold secret sharing scheme constructed by the existing solution couldn't meet the bound. Based on this scheme, an improved reconstruction algorithm was proposed and a higher communication rate ρ'=v/((t-l)(t-1)+tv)(≥ρ) was figured out. The result proves that ρ' is greater than the lower bound 1/t and can achieve the upper bound v/(t+v-1) when l=t+v-1.

An authentication protocol based on hybrid Das protocol for wireless sensor networks

WAN Zhi-ping

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 12-17. doi:10.6040/j.issn.1671-9352.0.2014.431

Abstract ( 1539 )

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In order to improve the security of legitimate user access to the node data in the wireless sensor networks(WSNs), an authentication protocol hybrid Das protocol for wireless sensor networks was proposed. This protocol has a dynamic authentication protocol by one-way hash function and XOR operation to achieve the encryption/decryption performance, and it also has a characteristic that Das protocol using only a smart card to authenticate. Compared with Das protocol and dynamic authentication protocol, MDas protocol increases the password change phase, and also increases the mutual verification operation between the login node and sensor nodes during the verification phase of the agreement to enhance the authentication security. The analysis on protocol security features comparison and calculation cost showed that the MDas protocol can resist the attack of camouflage gateway replay,and it has the better security performance.

E-commerce community clustering model based on trust

ZHU Rui

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 18-22. doi:10.6040/j.issn.1671-9352.0.2014.130

Abstract ( 1168 )

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Trust is an important factor affecting the development of E-commerce industry. Aiming at the trust issues of e-commerce community, a clustering model based on trust was proposed. First, the trust value of node relative to other node in network community was computed by indirect and direct trust information between them. And then based on the trust value computed, a clustering algorithm was promoted to form E-commerce clustering community. The simulation result shows that the clustering model based on the trust of high accuracy and convergence can better reflect the trust relationship among the subject of E-commerce community.

An efficient bittable based frequent itemsets mining algorithm

ZHAO Guan-bao, LIU Yun

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 23-29. doi:10.6040/j.issn.1671-9352.0.2014.306

Abstract ( 1389 )

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Fast and accurate mining frequent item set is the key of mining association rules in data mining techniques. The traditional Apriori-like algorithms need to scan the entire transaction database many times and spend too long time for mining frequent itemsets. Based on the efficient bittable, an based frequent itemsets mining algorithm BITXOR was proposed, which uses the bit table and represents item sets with binary sequence. BITXOR judges whether two items can be connected by the sequence of binary XOR. After the connection of item set, BITXOR also carries out pruning operation on the initial candidate sets. The simulation results show, compared with the traditional Apriori algorithm and FP-growth algorithm under the same conditions, BITXOR algorithm scans the entire transaction database only once and significantly reduces the time of mining frequent itemsets. The performances of BITXOR are more significant in conditions of intensive database.

Energy dissipation of granular block under vertical vibration

WANG Ying, KONG Wei-shu, HU Lin, SHI Tong-yang, ZHAO Chuang

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 30-34. doi:10.6040/j.issn.1671-9352.0.2014.263

Abstract ( 1356 )

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The internal energy dissipation of the granular block under the vertical vibrating was studied through the experiment. The average flight time of four granular blocks for different vibrating strength was measured. Dynamic analysis of the experimental results was carried out. The quantitative relationship of the average flight time and the vibrating strength and the internal friction factor was used to fit the relationship for fitting the experimental data, the fitting results are well agreed with the experimental results. Theoretical analysis of the experimental results show that the internal energy dissipation of different internal structure depends on the particle size, particle viscidity and vibrating frequency for a given vibrating strength. The internal energy dissipation character is mainly the collision dissipation of each other.

μ-reduction based on the subset of the objects in inconsistent information systems

QIU Ting-ting, LI Ke-dian

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 35-39. doi:10.6040/j.issn.1671-9352.0.2014.096

Abstract ( 1486 )

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The μ-reduction based on the subsets of the objects in inconsistent information systems is given by the equivalence relation on the set group. Also, some properties of μ-reduction,the judgement theorem and corresponding discernibility matrix with respect to the μ-reduction are obtained. And an approach to calculate μ-reduction is provided. A numerical example is used to illustrate the validity of this method.

Dynamic generation of stretching-shrinking data and data submerging and hiding

LU Sheng-rong, TANG Ji-hua

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 40-44. doi:10.6040/j.issn.1671-9352.0.2014.303

Abstract ( 1424 )

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Using dynamic structure of packet sets, the concepts, discrete stretching, shrinking and stretching-shrinking data are introduced, and then their dynamic generation and existing are given. Their existence theorems are proposed, and then the attribute shrinking theorem of discrete stretching data, the attribute stretching theorem of discrete shrinking data and the attribute theorem of discrete stretching-shrinking data are put forward. Using these results, the application of discrete stretching-shrinking data in data submerging and hiding is shown.

Existence of nonoscillatory solutions to second order forced neutral dynamic equations with time delay on time scales

FAN Jin-jun, LU Xiao-dong

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 45-50. doi:10.6040/j.issn.1671-9352.0.2014.361

Abstract ( 1454 )

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The existence of nonoscillatory solutions to a calss of second order forced neutral dynamic equations with time delay on time scales is discussed. The main tool is the Krasnoselskii's fixed point theorem.

Multiple homoclinic solutions for second order nonlinear difference equations

SUN Guo-wei, MAI A-li

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 51-54. doi:10.6040/j.issn.1671-9352.0.2014.241

Abstract ( 1287 )

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We study the existence of homoclinic solutions for a class of second order nonlinear difference equations. Under more general superlinear conditions, we prove the multiplicity results of the equations by using critical point theory.

Blow-up of a weakly dissipative μ-Hunter-Saxton equation

LÜ Hong-jie, LIU Jing-jing, QI Jing, LIU Shuo

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 55-59. doi:10.6040/j.issn.1671-9352.0.2014.275

Abstract ( 1113 )

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We study the Cauchy problem of the weakly dissipative μ-Hunter-Saxton equation. The present work is mainly concerned with blow-up phenomena of the equation. We first present a new blow-up result for strong solutions to the equation. Then, we drive the precise blow-up rate for strong solutions to the equation.

Regularity criteria for weak solutions to the 3D magneto-micropolar fluid equations

LI Feng-ping, CHEN Guang-xia

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 60-67. doi:10.6040/j.issn.1671-9352.0.2014.214

Abstract ( 1664 )

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We consider the regularity criteria of the weak solutions for the 3D magneto-micropolar fluid equations by energy method and Littlewood-Paley decomposition, and prove some regularity criteria involving the pressure or pressure gradient for weak solutions in Lebegue, Lorentz, BMO and Besov spaces.

Existence of nontrivial solutions for boundary value problems of fractional differential equations

MA Yan, ZHANG Ke-yu

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 68-73. doi:10.6040/j.issn.1671-9352.0.2014.317

Abstract ( 1568 )

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By applying the theory of Leray-Schauder degree, the existence of nontrivial solutions for the boundary value problems of fractional differential equations

is considered under some conditions concerning the first eigenvalue corresponding to the relevant linear operator.Here α∈(2,3]is a real number, D₀₊^α is the standard Riemann-Liouville fractional derivative of order α.

On a periodic dividend problems in the Brownian motion model with investment

WANG Cui-lian, LIU Xiao

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 74-81. doi:10.6040/j.issn.1671-9352.0.2014.316

Abstract ( 1101 )

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Assume that the dividends can only be paid at some randomized observation times and dividends were paid according to a barrier strategy, the differential equations for the moment-generating function, the n-th moment function and the Laplace transform of ruin time were derived. The explicit expressions for the expected discounted dividends until ruin and the Laplace transform of ruin time were also obtained.

Stability of neutral stochastic differential equations with some variable delays

WANG Chun-sheng, LI Yong-ming

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 82-87. doi:10.6040/j.issn.1671-9352.0.2014.237

Abstract ( 1612 )

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We consider a class of linear scalar neutral stochastic differential equation with some variable delays and give conditions to ensure that the zero solution is asymptotically stable in mean square by means of Banach fixed point method. Previously, when almost all the experts and scholars study the stability of stochastic differential equations by means of Banach fixed point, it is usually achieved and accomplished by introducing appropriate functions. Being different from most other study methods, we will split the introduced functions when studying the stability of stochastic differential equations with some variable delays to construct the operator in this paper. Then, study its stability by ways of Banach fixed point, promote and improve the previous studies. Also an example was given to illustrate the results in the paper.

Environmental factors influence on phosphorus removal of three halophilic phosphate accumulating bacteria strains

ZHANG Pei-yu, SUN Meng, ZHANG Chen

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2015, 50(05): 88-94. doi:10.6040/j.issn.1671-9352.0.2014.208

Abstract ( 1561 )

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Three halophilic phosphate accumulating bacterial strains qdp01, qdp03, qdp05 were separated and screened from the biological phosphorus removal sludge which was supplied with domestic sewage as carbon source under steady operation. The strain qdp01 were identified as Alcaligenes sp. by analyzing the morphology, physiology, biochemical features and 16S rDNA sequence. The strain qdp03 and qdp05 was identified as Enterobacter sp. Through researching their phosphorus removal by changing the temperature, pH, carbon sources and salinity, we get best environmental conditions for phosphorus removal. The results were as follows: when sodium acetate was used as carbon sources, temperature 30 ℃, pH 7.5-9, salinity 2%, the removal rates of the PO₄^3- by the three strains were all over 80%. We especially researched the effect of different salinity on strains growth and phosphorus removal, so that the three strains have great application value for phosphorus removal of hyperhaline wastewater.

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