Showing papers by "Harbin Engineering University published in 2000"

Preparation of CdS Single‐Crystal Nanowires by Electrochemically Induced Deposition

Abstract: CdS is one of the most important II-VI semiconductors, with applications in solar cells, optoelectronics. and electronic devices. Here a new process for the preparation of CdS single-crystal nanowires (see Figure) is presented, in which the nanowires are prepared by electrochemically induced deposition into the pores of anodic aluminum oxide templates.

Quasi-distributed strain sensing with white-light interferometry: a novel approach.

Abstract: An optical fiber ring is used to generate multiple reference waves in a multiplexed fiber-optic Michelson-type sensor array. The array consists of N sensing segments connected in series along a single optical fiber path and is interrogated with a white-light interferometric technique. Experimental results with a two-sensor array are presented.

Logistic-map chaotic spread spectrum sequences under linear transformation

Abstract: A typical chaotic system, Logistic Map, is studied under linear transformation. A model, LT-Logistic-Map, is proposed, and its statistical property is derived. The result shows that the model statistical properties are identical with those of white noise. LT-Logistic-Map chaotic sequences are suited for spread spectrum address codes. Using the new model, more chaotic sequences can be generated and the privacy of transmission in the spread spectrum communication system can be enhanced. The experimental results are very close to the theoretical values, which demonstrate that the derivations are effective and reliable.

Fiber optic temperature sensor with duplex Michleson interferometric technique

Abstract: An interferometric fiber optic temperature sensing system employing a light emitting diode (LED) as the broadband optical source and a single mode fiber coil, which was fabricated in definite length as the sensor head, is described. The fiber transmitting line back and forth along the same path is used, so the changing caused by the environmental temperature fluctuation of the fiber path can automatically be compensated. The sensitivity of the sensing system can be easily improved by using the long length of the sensing fiber. The experimental result of the sensing gauge length vs. the sensitivity is given. A typical wavelength 1300-nm LED source is used in the experiments. The experimental curve of the resolution characteristic of the system related with the length of sensing fiber coil is also discussed.

Application of the zero-crossing rate, LOFAR spectrum and wavelet to the feature extraction of passive sonar signals

Abstract: In this paper, the features extraction of passive sonar signals and classification recognition of underwater target are introduced. Due to the complexity and non-stationary of underwater signals, the zero-cross ratio is first used to initially classify the noise signal; then the LOFAR spectrum reflecting non-stationary signal is extracted, and during which the wavelet transform is carried out for some classes of signals. Finally, a fuzzy ART neural network is constructed to carry out the classification. Results of the experiment show that, for six-class target 147 running environments, 5000 realistic data of ship, the mean correct ratio achieves 89%. The result obtained is satisfactory.

Applications of angled-mirror in fiber-optic sensors

Abstract: An angled-mirror as fiber-optic sensor's reflective modulator is introduced. This paper reports two optical-fiber sensors based on the angled-mirror reflective modulator. One is fiber-optic sliding sensor, the other is called fiber-optic three-states-position sensor.

Fiber optic differential interferometer

Abstract: Based on low-coherence interferometry in standard single-mode fibers, a differential interferometer has been proposed. A twin-reflective mirror demodulator was used in the differential interferometer. This interferometer can be used as a fiber optic sensor to measure the elongation of the fiber or strain substressed on the fiber and has the advantage that it can automatically compensate for temperature-induced variations in the refractive index and thermal expansion of the silica fibers.

Neural network based online self-learning adaptive PID control

Abstract: An improved backpropagation neural network (BPNN) based online self-learning adaptive PID control strategy is presented. A feedback PID controller tuned by the critical proportion method works at the beginning of the control process. With the learning of a BPNN controller, it gradually compensates the deficiency of the feedback together perfectly. The design of the controller is independent on the empirical knowledge of the system, and the parameters are tuned based on the testing information and error feedback learning algorithm. The results of the simulation show that the structure of this method is simple and its performance is substantially outperform the normal PID controllers.

Research on reinforcement learning of the intelligent robot based on self-adaptive quantization

Abstract: The concept of the reinforcement learning comes from behavior psychology that takes behavior learning as trial and error, by which the states of the environment are mapped into corresponding actions. There is a question of how can the behaviourism be used to learn the actions in interaction with the environment in designing an intelligent robot. In the paper, the actions that the robot takes to avoid obstacles are taken as one class of behaviors and the reinforcement learning is used to realize behavior learning of obstacle avoidance. The quantization of the state space is very important in improving the robot's learning speed. The SOM neural network is adopted to get self-adaptive quantization of the state space. The self-organization characteristic of the SOM neural network makes it possible to solve the adaptation problem and is flexible in space quantization. The reinforcement learning is used to settle the robot learning of collision avoidance behavior based on quantization of the state space and satisfying results are obtained.

The features of two forward looking sonars for ROV/UUV and their experimental results

Abstract: In this paper, the features of two new forward looking sonars for remotely operated vehicle/unmanned underwater vehicle (ROV/UUV) are described. These two sonars have different system structures: one is composed of a rectangular acoustic array and parallel DSP central processing unit; and the other one is composed of a cross-line array and single fast DSP board as a central processing unit. Both of them include other common and necessary components which have been modularized. The new software for high resolution acoustic imaging developed for both sonars are also presented. A comparison and analysis of experimental results from these two sonars is presented. Finally, conclusions based on a number of imaging experiments are given.

Influence of couple-stresses on stress concentrations around the cavity

Abstract: The complex function method was used in the solution of micropolar elasticity theory around cavity in an infinite elasticity plane. In complex plane, the general solution of two dimension micropolar elasticity theory is given. The solution comes from analytic function and “Zonal Function”. The boundary conditions of non-circular cavity are satisfied by using the conformal mapping method. Based on the method, a general approach solving the stress concentration in micropolar elasticity theory is established. Finally, the numerical calculation is carried out to the stress concentration coefficient of circular cavity.

A Design Methodology for Robust Two-Degree-of-Freedom Digital Preview Tracking Controllers

Abstract: This paper presents a design method for digital tracking control systems in which the plant has structured uncertainties. A two-degree-of-freedom control system configuration is utilized to achieve the desired feedback and input-output performances independently. First, sampleddata H∞ control and linear matrix inequality approaches are used to design a static state feedback controller and a reduced-order output feedback controller. Then, the parameterization of a feedforward controller is carried out based on the feedback controller, in which the free parameter is chosen to achieve the desired transient response using a preview strategy.

Research on Cooling Schedule Selecting Method in Simulated Annealing Algorithm

Abstract: Cooling schedule is the key to simulated annealing algorithm that is effective means to solvs combination optimal problem. In this paper. some selecting criteria are given about cooling schedule including initial temperature. temperature dropping strategy. Markov chain length and stopping criterion, especiallv about stopping criterion of simulated annealing algorithm. a new criterion is presented similar to the one in tabu search. The above conclusions are successfully applied in the traveling salesman problem of 31 cities in China and in the dithering pattern problem.

The study of flapped fin service system of main/flapped fin stabilizer

Abstract: The paper studies the control law of flapped fin service system in the joint control system of main/flapped fin stabilizer. LQ inverse design based on pole placement method is used by means of state feedback inverse design. /spl Hscr//sup /spl infin// control theory is also adopted to design flapped fin service system. Both the simulation results are given and contrasted with result designed by classical control theory. So the two modern control theory advantages are concluded.

Image-based recognition of the chip shape

Abstract: According to the profile characteristics of the extracted chip form and the number of nodes between profile and * line which have the same gravity, chip species are discerned. The chip types near the critical joint are judged exactly through the standard tolerance of all direction nodes. It was tested to have a high accordant rate.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The study of flapped fin service system of main/flapped fin stabilizer

Abstract: The paper studies the control law of flapped fin service system in the joint control system of the main/flapped fin stabilizer. An LQ inverse design based on the pole placement method is used by means of the state feedback inverse design. The H/sup /spl infin// control theory is also adopted to design the flapped fin service system. The simulation results are given and contrasted with the result designed by the classical control theory. The advantages of the modern control theory are validated.

A research of signal processing in wideband passive radar goniometer system

Abstract: The rationale of a wideband antimissile radar receiver is briefly introduced in this paper. Signal processing of the radar goniometer system has been discussed in detail. The least squares technique is used to remove the errors which are introduced by the asymmetry of the receiver's two channels. The experimental results confirm that it has good performance.

Structured-light based on shaped depth-image capturing system

Abstract: At first, this paper introduces the structure of the design- image capturing system using the single-stripe pattern. At second, its operating principle is introduced, its mathematical model is established and the calibrating method for it is put forward. At last, its prototype is produced and calibrated.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

AUV global path planning allowing for ocean current

Abstract: Proposes a paradigm, which uses the activity propagation algorithm for autonomous underwater vehicle (AUV) global path planning. According to the information of the environment structure, the paradigm effectively combines the grid algorithm with the basic idea of configuration space and solves the problem of pole-like robot path planning under the influence of ocean current. In the process of heuristic search, the evaluation function takes into account both the energy cost and the length of paths. The paradigm proves to be flexible and practicable, and improves the autonomy of the AUV greatly.

Synthesis, 2D NMR, electrochemistry and luminescence of ruthenium(II) complexes with 2,2 '-bipyridine and 5-(omega-bromoalkylamido)-1,10-phenanthroline

Abstract: The efficient synthesis of 5-(5-bromovaleramido)-1,10-phenanthroline, 5-(6-bromohexanamido)-1,10-phenanthroline, and 5-(11-bromoundecanamido)-1,10-phenanthroline are described, which reacted with cis-Ru(bpy)(2)Cl-2. 2H(2)O and sodium hexafluorophosphate to form Ru(bpy)(2)[phen-NHCO(CH2)(n)Br](PF6)(2) (n = 4, 5 or 10; phen = 1,10-phenanthroline). The intricate H-1 NMR spectra at low field of these complexes were completely assigned in virtue of H-1-H-1 COSY technique. Cyclic voltammetry was used to study electrochemical behaviours of these complexes, and their luminescent properties were investigated with fluorescent spectra.

Estimation of boundary parameters and prediction of transmission loss based upon ray acoustics

Abstract: We present an estimation of boundary parameters and prediction of transmission loss using a sound propagation channel model based on ray acoustics, and sound propagation data collected in field experiments are presented. Comparison between the predicted results and the experiment data indicates that the adopted sound propagation channel model is effective, both the selection and estimation methods on boundary parameters are reasonable, and the prediction performance of transmission loss is favorable.

The study of H/sup /spl infin// controller of flapped fin service system

Abstract: This paper proposes a method to design the flapped fin service system using the H/sup /spl infin// control theory. The problems are solved that the flapped fin service system doesn't match the H/sup /spl infin// control theory because of the characteristics of flapped fin service system. At the same time, a new method is proposed to solve the problem of H/sup /spl infin// disturbance restrain.

Making and using multimedia timer

Abstract: The shortage of the general timer and the advantage of the multimedia timer in Windows when developing a large application program are analyzed in this paper .The method of making and using the multimedia timer is also researched in it. The program example by VC++ is presented in the end.

Filter algorithm of Bayesian state estimation using FFT

Abstract: In the paper, a filter algorithm of Bayesian state estimation using fast Fourier transforms (FFTs)is proposed. The computation is reduced by using FFTs. The simulation result shows that the algorithm is a very robust nonlinear filter algorithm.

Localized and distributed fiber optic strain sensors based on white light interferometric techniques

Abstract: Strain, deformation and temperature measurements constitute the most interesting parameters to be monitored in smart structures White-light interferometry offers these performances even for long-term measurements Based on the Michelson interferometer, a fiber optic localized strain sensor and multiplexing strain-sensing techniques are demonstrated in this paper Related problem about the spatial division limitation of fiber optic sensors is discussed Finally, application examples such as cable strain measuring of cable-stayed bridge model, inside strain measurements for concrete specimens and temperature monitoring are also given

The complementary property of lindelöf’s work and chaplygin’s work

Abstract: Lindelof' s equation is derived by using the Vakonomic model, which shows that Lindelof' s work coincides with Vakonomic model. Chaplygin' s equation is derived by using Chetaev' s model, which shows that Chaplygin' s work coincides with Chetaev' s model. On basis of these, by improving the expressions of Chaplygin' s equation and Lindelof' s equation, the reasonable transition from Chaplygin' s equation to Lindelof's equation is realized, the reasonable transition from Lindelof's equation to Chaplygin' s equation is realized too. Finally, a typical example is given. The work of this paper shows that, just as the Vakonomic model and Chetaev's model are complementary to each other, Lindelof' s work and Chaplygin' s work are complementary to each other too.

An application of theoretical solutions about cylindrical shells with small openings

Abstract: Stress concentrations about thin cylindrical shells with small openings are reconsidered from a new angle. There is a sort of special internal relation between theoretical solutions about cylindrical shells with large openings and one with small openings. Using this relation, the extent of applying the theory about small openings to engineering practice is estimated again, thus an idea of how to use this theory and a new appraisal of the application of theoretical solutions about cylindrical shells with small openings to engineering practice are given.

A new method for design of fuzzy logic systems

Abstract: In order to improve the accuracy of a chaotic optimization method, the paper describes a hybrid algorithm called chaos-simplex search by combining a chaotic optimization method and a simplex search. Then this new algorithm is used for design of a fuzzy logic system. Simulation results show that the chaos-simplex search algorithm can avoid a great deal of adjusting work of the design process and is a more effective and simple method for design of a fuzzy logic system.