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IEEE International Conference on Information and Automation

作者： Wei Ba Jiasheng Qu Zhimin Zhou Qi Li The Key Laboratory for Underwater Scientific Test and Control Technology Dalian Scientific Test and Control Technology Institute School of Control Science and Engineering Dalian University of Technology

ISBN: (纸本)9781467391054

When the wavelet packet is used to extract signal, the result is greatly affected by the coefficient quantization threshold. It is difficult for the threshold to reflect the current state of the signal accurately, which leads to the failure of signal extraction. A novel method of extracting signal based on fuzzy threshold for wavelet packet is proposed in this paper. The wavelet packet decomposition coefficient is quantified by fuzzy threshold method. The concept of the maximum value of noise to signal ratio is given to characterize the signal's strength compared to the noise in the simulation experiment. The frequency distribution probability is computed. The maximum value of noise to signal ratio and the frequency distribution probability are used as fuzzy input. To make the computing of fuzzy threshold conveniently, the fuzzy output is set by fixed value. The simulation results show that the method can meet the needs of different frequency signals, compared to conventional filtering and matched filtering, the novel method can inhibit the influence of the noise on the signal effectively, enhance the signal extraction ability and improve the detection distance.

关键词： Wavelet packet coefficients Wavelet packet reconstruction Fuzzy threshold Signal extracting

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Software design for theory analysis of underwater electromagnetic field in shallow sea environment

Software design for theory analysis of underwater electromag...

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2014 International Conference on Applied sciences, Engineering and technology, ICASET 2014

作者： Cui, Pei Wu, Liang Jiang, Kai Na Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China Dalian Scientific Test and Control Technology Institute Dalian 116013 China

ISBN: (纸本)9783038351849

The driving sources of the marine environment underwater electromagnetic field are complicated, the environmental parameters working on field source amplitude are numerous. The paper filters out the main respective factor through comparative analysis, on the basis of which composes theoretical analysis software of electromagnetic field underwater and the main environmental factors. The result shows that it is easy to get the variations of field source amplitude and main environmental parameters by setting the main environmental parameter values and field source forms. © (2014) Trans Tech Publications, Switzerland.

关键词： Software design

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Ballast water discharge and the influence of seawater environment

Ballast water discharge and the influence of seawater enviro...

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4th International Conference on Materials science and Information technology, MSIT 2014

作者： Li, Xiao Yan Liu, Sha Zhou, Zhi Min College of Life Science and Technology of Dalian University Liaoning Dalian 116622 China Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

ISBN: (纸本)9783038351733

Ships have carried solid ballast for thousands of years in the form of rocks, sand or metal. In modern times, ships use water as ballast. It is more easier to load on and off a ship and more efficient and economical than solid ones. Ship fills with ballast water when it is empty of cargo, and the ballast water is discharged when it loads cargo. In ballast water, there are hundreds of organisms carried that cause problematic ecological effects outside of their natural range. Preventing the transfer of invasive species and coordinating a timely and effective response to invasions require cooperation and collaboration between governments. Considerable efforts had already made to formulate appropriate standards for ballast water management during the convention development process. © (2014) Trans Tech Publications, Switzerland.

关键词： Ships

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Comparative bioenergetics of diploid and triploid pacific oysters Crassostreas gigas at different temperatures

Comparative bioenergetics of diploid and triploid pacific oy...

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4th International Conference on Materials science and Information technology, MSIT 2014

作者： Li, Xiao Yan Zhou, Zhi Min College of Life Science and Technology of Dalian University Liaoning Dalian 116622 China Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

ISBN: (纸本)9783038351733

The energy budgets, assimilation and conversion efficiency of 1-year-old-triploid Pacific oysters Crassostrea gigas, were compared with those of sibling diploids to clarify the mechanism of energy metabolism. No significant difference was found between diploids and triploids in oxygen consumption. The net growth efficiencies of triploids and diploids were 37.4% and 33.9% respectively, and the gross growth efficiencies of them were 28.8% and 22.7%. The influence of ploidy and temperature on K1 was significant, but the variation of K2 may be attributable to ambient temperature. The ratio of gonad dry weight and dry tissue of triploids was 5% on average, and diploids about 25.6%. Our results showed that triploids, which do not reproduce and only have limited gonadal development, spend more energy for growth and more efficient in using energy than diploids do. © (2014) Trans Tech Publications, Switzerland.

关键词： Molluscs

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Blind source separation of the fractional fourier domain in reverberation background

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Information technology Journal 2013年第7期12卷 1459-1463页

作者： Sun, Shijun Li, Xiukun Li, Wenwen Mu, Lin Science and Technology on Underwater Acoustic Laboratory Harbin Engineering University Harbin 150001 China Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

To resolve the problem that reverberation signal usually seriously affect active sonar's detection performance, Blind Source Separation method of the Fractional Fourier Domain is adopted in this study. First, the Fractional Fourier Transform is used to enhance the signal-to-reverberation ratio. And then the separation condition is analyzed and target echo is separated from the received signal by using the Blind Source Separation method. At last, the highlight characteristic of the underwater target is extracted. Simulation and experiment data processing affirm the effectiveness of the proposed method. © 2013 Asian Network for Scientific Information.

关键词： Blind source separation

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Simulation for range prediction of active sonar in shallow water

Simulation for range prediction of active sonar in shallow w...

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2013 International Conference on Mechanical and Electronics Engineering, ICMEE 2013

作者： Zhang, Liang Meng, Chun Xia Na, Jian Science and Technology on Underwater Test and Control Laboratory Dalian 11601 China

ISBN: (纸本)9783037858103

In shallow water the acoustic wave from ambient noise sources carries a large number of environment information based on the complicated reflection both on the surface and seabed interface. The sound speed profile is one of the influencing factors of sound propagation characteristic, while for a long distance the sound absorption coefficient of water medium has an important significance to propagation range. The simulation results show that in shallow water sound absorption of seabed, sound speed profile and sound absorption of water were taken into account, then range prediction of active sonar can be exactly obtained using normal-mode propagation. © (2013) Trans Tech Publications, Switzerland.

关键词： Forecasting

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High voltage triggered spark gap with repeatable gas filling structure

High voltage triggered spark gap with repeatable gas filling...

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International Symposium on Mechatronics and Applied Mechanics, ISMAM 2013

作者： Tian, Z.X. Science and Technology on Underwater Test and Control Laboratory Dalian 116013 China

ISBN: (纸本)9783037858875

To resolve the problems of short working life and narrow operating voltage range of the spark gap with one-offin gas filling structure, a spark gap with repeatable gas filling structure was designed. The spark gap was composed of three electrodes and two gaps as well as gas filling devices. Electrodes structures adopted the form of field aberration three-electrode gas spark switch forming two discharge gaps between three electrodes of anode, cathode and triggering electrode. Gas filling devices were composed of fast connector, gas pipe, barometer and air valve, by which the gaps could be repeatedly charged and deflated from a hole at the center of anode. Working life is lengthened by exchanging gas, and operating voltage range is widened by changing gas pressure in a certain range. The spark gap was manufactured and applied successfully in a TEA CO2 laser with pulse energy 170J. The results prove the designs feasible. © (2013) Trans Tech Publications, Switzerland.

关键词： Anodes

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Geo-acoustic parameters inversion from vertical coherence characteristic of ambient noise

Geo-acoustic parameters inversion from vertical coherence ch...

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2013 International Conference on Mechanical and Electronics Engineering, ICMEE 2013

作者： Meng, Chun Xia Li, Gui Juan Zhang, Liang Science and Technology on Underwater Test and Control Laboratory Dalian 11601 China

ISBN: (纸本)9783037858103

In shallow sea the wave of ambient noise contains the information of environment acoustic field. In theory, vertical coherence, which is one of the numerous ambient noise field characters, can be used to invert geo-acoustic parameters because of its relative stability. The ambient noise data were collected in two different seasons using two vertical-laid hydrophones in shallow water. Then acoustic parameters of semi-infinite space seabed are inversed from the vertical coherence of measured ambient noise in the frequency range of 100Hz~3 kHz. The predicted vertical coherence curve of ambient noise, which is computed using inversed parameters, agrees with the measured curve by comparison. The experiment results show that geo-acoustic parameters can be inversed effectively by the vertical coherence of ambient noise. © (2013) Trans Tech Publications, Switzerland.

关键词： Acoustic fields

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Research on algorithm for blind source separation based on negentropy maximization

Research on algorithm for blind source separation based on n...

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2nd International Conference on Mechanical Engineering, Industrial Electronics and Informatization, MEIEI 2013

作者： Sun, Bo Qiu Tian, Zuo Xi National Key Laboratory of Science and Technology on Underwater Test and Control Dalian 116013 China

ISBN: (纸本)9783037858905

To detect week signal of underwater magnetic fields, we designed a negentropy maximization blind source separation algorithm based on the stochastic gradient descent algorithm by bring in a penalty factor. The simulation study demonstrates that the new algorithm is effective to separate the mixed-signal with high precision, to decrease the iterative calculation and to enhance the convergence rate. © (2013) Trans Tech Publications, Switzerland.

关键词： Blind source separation

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High Voltage Triggered Spark Gap with Repeatable Gas Filling Structure

High Voltage Triggered Spark Gap with Repeatable Gas Filling...

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2013 International Symposium on Mechatronics and Applied Mechanics(ISMAM 2013)

作者： Z.X.Tian Science and Technology on Underwater Test and Control Laboratory

To resolve the problems of short working life and narrow operating voltage range of the spark gap with one-offin gas filling structure,a spark gap with repeatable gas filling structure was *** spark gap was composed of three electrodes and two gaps as well as gas filling *** structures adopted the form of field aberration three-electrode gas spark switch forming two discharge gaps between three electrodes of anode,cathode and triggering *** filling devices were composed of fast connector,gas pipe,barometer and air valve,by which the gaps could be repeatedly charged and deflated from a hole at the center of *** life is lengthened by exchanging gas,and operating voltage range is widened by changing gas pressure in a certain *** spark gap was manufactured and applied successfully in a TEA CO2 laser with pulse energy *** results prove the designs feasible.

关键词： Spark gap Working life Gas filling structure Operating voltage Envelope

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