Showing papers by "Harbin Engineering University published in 2004"

Research on particle swarm optimization: a review

Abstract: Particle swarm optimization (PSO) explores global optimal solution through exploiting the particle's memory and the swarm's memory. Its properties of low constraint on the continuity of objective function and joint of search space, and ability of adapting to dynamic environment make PSO become one of the most important swarm intelligence methods and evolutionary computation algorithms. The fundamental and standard algorithm is introduced firstly. Then the work on the algorithm improvement during the past years is surveyed, as well as the applications on the multi-objective optimization, neural networks and electronics, etc. Finally, the problems remaining unresolved and some directions of PSO research are discussed.

The research and implementation of intelligent intrusion detection system based on artificial neural network

Abstract: An intrusion detection system is an important component of the computer and information security framework. Its main goal is to differentiate between normal activities of the system and behaviors that can be classified as suspicious or intrusive. The research aims at the design, implementation and evaluation of an intelligent intrusion detection system based on artificial neural network that can promptly detect attacks, no matter they are known or not. In this system, neural network is used to learn about the normal users' behavior to form the network traffic that only contains information about normal users. When the learning is over, the system is tested with the network traffic that contains both attacks and normal data. A simulated computer network is used to test the system performance. In experiments, system performance has been compared with other research works and the results in experiments are very promising.

A hidden Markov models-based anomaly intrusion detection method

Abstract: Intrusion detection has emerged as an important approach to security problems. The existing techniques are analyzed, and then an effective anomaly detection method based on HMMs (hidden Markov models) is proposed to learn patterns of Unix processes. Fixed-length sequences of system calls were extracted from traces of programs to train and test models. The RP (relative probability) value, which uses short sequences as inputs, is computed to classify normal and abnormal behaviors. The algorithm is simple and can be directly applied. Experiments on sendmail and lpr traces demonstrate that the method can construct accurate and concise discriminator to detect intrusive actions.

Scattering of sh-waves by an interacting interface linear crack and a circular cavity near bimaterial interface

Abstract: An analytical method is developed for scattering of SH-waves and dynamic stress concentration by an interacting interface crack and a circular cavity near bimaterial interface. A suitable Green's function is contructed, which is the fundamental solution of the displacement field for an elastic half space with a circular cavity impacted by an out-plane harmonic line source loading at the horizontal surface. First, the bimaterial media is divided into two parts along the horizontal interface, one is an elastic half space with a circular cavity and the other is a complete half space. Then the problem is solved according to the procedure of combination and by the Green's function method. The horizontal surfaces of the two half spaces are loaded with undetermined anti-plane forces in order to satisfy continuity conditions at the linking section, or with some forces to recover cracks by means of crack-division technique. A series of Fredholm integral equations of first kind for determining the unknown forces can be set up through continuity conditions as expressed in terms of the Green's function. Moreover, some expressions are given in this paper, such as dynamic stress intensity factor (DSIF) at the tip of the interface crack and dynamic stress concentration factor (DSCF) around the circular cavity edge. Numerical examples are provided to show the influences of the wave numbers, the geometrical location of the interface crack and the circular cavity, and parameter combinations of different medial upon DSIF and DSCF.

The First Silver(I) Side-On η2-Coordination Network Formed by Self-Assembly of Bis(pyrrol-2-ylmethylene)hydrazine

Abstract: This paper reports the first silver(I) network polymer formed by the self-assembly of bis(pyrrol-2-ylmethylene)hydrazine with silver nitrate, in which the silver centers are bonded to the C−N bonds of the pyrrole rings in an η2-fashion. An X-ray crystal structure analysis revealed that the self-assembly of the bis(pyrrol-2-ylmethylene)hydrazine ligand with AgI gives a 2D sheet, which is further assembled to form a 3D network through weak intermolecular hydrogen bonding between the protons of the pyrrole rings and the oxygen atoms of the nitrate ions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

The experimental study on GPS/INS/DVL integration for AUV

Abstract: To Navigate the Autonomous Underwater Vehicle (AUV) accurately is one of the most important aspects in AUV's study. The paper presents the basic composition and integration method of the AUV's navigation system using Extended Kalman Filtering (EKF) technique. In the specified application, GPS receiver, Strapdown INS and Doppler Velocity Log (DVL) are mounted aboard on the test vessel. The 3-day experiment was carried out in Songhua Lake, nearby Harbin City. The test results show that the system is able to achieve high precision, which is one meter approximately, with GSP and DVL working properly. Without GPS augmentation, which is the usual configuration for AUV application, accurate positioning and navigating results are still available, provided that the DVL satisfies its working requirements. Under this situation, a 3-meter precision could be reached. Besides the theoretical and experimental analysis of the integrated navigation system, the alignment technique in swing base is also discussed in detail.

An encoding scheme for indexing XML data

Abstract: E-services are becoming a promising technology for the effective automation of application integration across the Web. They build upon XML, as data format for exchanging messages between applications. Accompanied with WSDL, UDDI, and SOAP, XML has clearly influenced positively the development of applications running on the Web. As the basic technology, indexing scheme for XML data have been studied in recent years to optimize path query processing by summarizing path information. However, most of these schemes based on tree traversals may not meet the processing requirements under heavy access requests. In this paper, we proposed a new scheme for indexing XML data using encoding elements, termed ES-index, and its algorithms. This encoding scheme quickly determines the siblings-siblings and ancestor-descendant relationship in hierarchy of XML data. Our experiment results over a wide range of XML documents demonstrate that ES-index structure is efficient for data access.

The design of underwater hull-cleaning robot

Abstract: The research on underwater ship-hull cleaning robot was conducted on the purpose of realizing the automation of cleaning underwater ship hull so that service life of ship will be prolonged and ship speed will raised. Moreover, fuel consumption and the work intensity of divers will be reduced. In this paper, the current situation and the latest technology in China and abroad were analyzed; meanwhile, the typical characteristics of the underwater cleaning robot were introduced. According to the work principle of the underwater cleaning robot, the emphasis was put on the analysis and study of permanent-magnetic absorption, magnetic wheel, airproof and anticorrosion, underwater cleaning equipment and control system. The robot is easy in rotation and simple in control.

Nonlinear parabolic equations with critical initial conditions J(u0)=d OR I(u0)=0

Abstract: In this paper we study the initial boundary value problem of nonlinear parabolic equation ∂ u ∂ t = ∑ i=1 N ∂ ∂ x i ∂ u ∂ x i p−2 ∂ u ∂ x i +u 1+α , x∈Ω, t>0, u(x,0)=u 0 (x), x∈Ω, u(x,t)=0, x∈ ∂ Ω, t⩾0, where Ω⊂ R N is a bounded domain, p α p ⩾ N ; p Np N−p if p N . By using potential well method we prove that if 0⩽u 0 (x)∈W 0 1,p (Ω) , J ( u 0 )= d , I ( u 0 )>0 or I ( u 0 )=0, 0 J ( u 0 )⩽ d , then the problem admits a global solution u(t)∈L ∞ (0,∞;W 0 1,p (Ω)) with u t (t)∈L 2 (0,∞;L 2 (Ω)) and u(t)∈ W for 0⩽ t

Multidimensional viscoelasticity equations with nonlinear damping and source terms

Abstract: In this paper we study the initial boundary value problem of multidimensional viscoelasticity equations u tt − Δ u t − ∑ i=1 N ∂ ∂x i σ i (u x i )+f(u t )=g(u), x∈Ω, t>0, u(x,0)=u 0 (x), u t (x,0)=u 1 (x), x∈Ω, u(x,t)=0, x∈∂Ω, t⩾0, where Ω⊂ R N is a bounded domain, (σi(s1)−σi(s2))(s1−s2)>0, f(s)s⩾0, g(s)s⩾0 and satisfy some growth conditions. First we introduce a family of potential wells by using a new method. Then using it we obtain some new existence theorems of global solutions and behaviour of vacuum isolation of solutions.

Wet Compression System Stability Analysis: Part II — Simulations and Bifurcation Analysis

Abstract: In this part, wet compression system stability performances are theoretical analyzed with bifurcation theory, and a basic wet compression system stability bifurcation model is established. Numerical simulations are carried out with MATLAB SIMULINK to verify the wet compression effects on the stabilities of compression system. The results indicate that wet compression can not only restrain the rotating stall, but also can diminish the surge, except for some extreme mismatching cases. Therefore, wet compression can be another useful method to help improving the stability performance and increase the stable working range of gas turbine.© 2004 ASME

The measurement and evaluation of distribution transformer losses under nonlinear loading

Abstract: Harmonic currents, generated by nonlinear electronic loads, produce 'penalty losses' in every element of an electrical distribution system. These harmonic-related losses reduce system efficiency, cause apparatus overheating, and increase power and air conditioning costs. Harmonic currents effectively de-rate existing systems and, when accommodated, add substantially to the capital cost of new distribution systems. The measurement and evaluation of transformer losses under linear and nonlinear load conditions will be discussed. In addition, typical financial benefits that result from the application of high efficiency harmonic mitigating distribution transformers, under nonlinear loading, will be calculated.

A new intrusion detection method based on behavioral model

Abstract: Intrusion detection has emerged as an important approach to network security. A new method for anomaly intrusion detection is proposed based on linear prediction and Markov chain model. Linear prediction is employed to extract features from system calls sequences of the privileged processes which are used to make up of the character database of those processes, and then the Markov chain model is founded based on those features. The observed behavior of the system is analyzed to infer the probability that the Markov chain model of the norm profile supports the observed behavior. A low probability of support indicates an anomalous behavior that may result from intrusive activities. The experiments show this method is effective and efficient, and can be used in practice to monitor the computer system in real time.

Design of a distributed intrusion detection system based on independent agents

Abstract: The common problems of current intrusion detection systems are analyzed in this paper. Based on these, a distributed IDS framework model based on independent agents is proposed. This paper describes the function of entities, and defines the communication mechanism. The proposed model is an open system, which has good scalability. Agents are independent individually, while they can communicate and cooperate one another to take actions. In the end, directions for future work are discussed.

A Fuzzy Set Based Trust and Reputation Model in P2P Networks

Abstract: Trust plays an important role in making collaborative decisions, so the trust problem in P2P networks has become a focus of research. In this paper, a fuzz set based model is proposed for building trust and reputation in P2P collaborations based on observations and recommendations, and using fuzzy set a peer can present differentiated trust and combine different aspects of trust in collaborations. Depending on fuzzy similarity measure, a good recommenders set can be maintained. The evaluation of the model using simulation experiments shows its effectiveness.

Long-gauge length embedded fiber optic ultrasonic sensor for large-scale concrete structures

Abstract: A fiber optic ultrasonic sensor based on Fizeau interferometer has been developed and demonstrated. A helium–neon laser light source with wavelength 0.6328 μm is used in our experiment. A special feature is its Fizeau configuration, which enables one to eliminate much undesirable noise by combining both the reference arm and the sensing arm within the same length of fiber. The dynamic response model of photo-elastic effect of ultrasonic wave and optical fiber is established. The fiber optic ultrasonic sensor experimental results are obtained and compared with the convenient PZT transducer.

An induction learning approach for building intrusion detection models using genetic algorithms

Abstract: Building and updating an effective intrusion detection system is complex engineering knowledge. A method of learning the intrusion detection rules based on Genetic Algorithms is presented in order to realize the automation of the detection models. The same attributes of an intrusion can be found through the heuristic search in the network data space. In our experiments the characters of an attack, such as smurf, are summarized inductively through the datasets of the 1998 DARPA Intrusion Detection Evaluation Program. The effectiveness and robustness of the approach are proved.

Wet Compression System Stability Analysis: Part I — Wet Compression Moore Greitzer Transient Model

Abstract: Wet compression Moore-Greitzer stability model is established in this paper. Transient performances of wet compression system are investigated and discussed. The model can be used for instabilities analyses of wet compression gas turbine, and be used for active control of compression system instabilities. The simulation results indicate that water injection is not only a technique to improve the thermodynamic performance of gas turbine, but also be an effective method to stabilize the instabilities of the compression system, surge and rotating stall.Copyright © 2004 by ASME

Research of the inertial navigation system with variable damping coefficients horizontal damping networks

Abstract: This work discusses the choice principles and methods of optimal 2-order horizontal damping network (HDN) in inertial navigation system, gives out optimal 2-order horizontal damping networks in various damping coefficients, and reduces the integrated inertial mathematic model of navigation system. By simulation, it shows that the inertial navigation system with variable coefficients horizontal damping networks has higher precision in motion voyage.

Applications of Fuzzy Data Mining Methods for Intrusion Detection Systems

Abstract: Two data mining methods (association rule mining and frequent episode mining) have been proved to fit to the intrusion detection problem. But the normal and the intrusions in computer networks are hard to predict as the boundaries between them cannot be well defined. This prediction process may generate false alarms in many anomaly based intrusion detection systems. This paper presented a method to realize that the false alarm rate in determining intrusive activities can be reduced with fuzzy logic. A set of fuzzy rules can be used to define the normal and abnormal behavior in a computer network, and fuzzy data mining algorithms can be applied over such rules to determine when an intrusion is in progress. In this paper, we have introduced modifications of these methods that mine fuzzy association rules and fuzzy frequent episodes and have described off-line methods that utilize these fuzzy methods for anomaly detection from audit data. We describe experiments that explore their applicability for intrusion detection. Experimental results indicate that fuzzy data mining can provide effective approximate anomaly detection.

Research on beamforming of wide nulling algorithm

Abstract: The adaptive beamforming algorithm can place the null in the direction of the jammer. When the interferer moves quickly or the antenna platform vibrates, it is possible that the weight mismatches the data of measurement due to the perturbation of the interferer location.Proposed is an algorithm that broadens the null width and is independent of the direction of the interferer by the rotation of the steering vector. When the data mismatch is smaller, the broadening null technology can effectively suppress interference, which increases the robustness of the algorithm. The results of computer simulation verify the efficiency of the proposed method and shows that it can work robustly when the interferer moves quickly or the antenna platform vibrates slightly.

Landmine Feature Extraction and Classification of GPR Data Based on SVM Method

Abstract: In this paper, the problem of detecting buried landmine is tackled in the feature extraction and classification Determining the likelihood set of an unknown pattern (feature vector), extracted from ground penetrating radar data by using SVM method The advantage of SVM method in feature extraction and classification of image processing is: A classifier works well both on the training samples and on previously unseen samples; In addition, the SVM provides, enable a classification performance improvement based on from high feature dimensions to two or three feature dimensions Finally, SVM method has a standard theory and a good implementation algorithm