Applied Mechanics and Materials Vols. 128-129

Abstract: An image hided-data detection method is proposed combining 2-D Markov chain model and Support Vector Machines (SVM) by the paper, in which image pixels are predicted with their neighboring pixels, and the prediction-error image is generated by subtracting the prediction value from the pixel value. Support vector machines are utilized as classifier. As embedding data rate being 0.1 bpp, experimental investigation utilizing spread spectrum (SS) and a Quantization Index Modulation (QIM) method data hiding method respectively , correction detection rates are all above 90% . For optimum LSB method ,the method achieves a detection rate from 50% to 90% above with 0.01bpp-0.3bpp various embedding data rates.

Abstract: An imaging processing method for the linear array antenna ISAR (LAA ISAR) was concerned in this paper. Range-Doppler algorithm was adopted to realize the image of each echo first; then the cross-correlation method was used for rough registration. On the basis of it, the method based on image entropy was used for precise registration. Simulations based on this method showed that the image registration was realized finely, and the target resolution was enhanced effectively.

Abstract: A Robert operator edge detection algorithm based on Bidimensional Empirical Mode Decomposition (BEMD) to detect medical liquid opacity is proposed. This method can effectively resolve the problem that traditional Robert operator edge detection can be easily effected by noise, and it also has certain effects on restraining external environment influence. The simulation results show that, compare with traditional medical liquid opacity detection methods, the proposed method could achieve higher detection accuracy, and has a certain theory and application value.

Abstract: Wireless Ad Hoc Network is a distributed self-organizing networking with no infrastructure and central control. To probe the unknown environment and obtain the associated data, this paper offers a Multi-Strategy Data Transmission Scheme (MSDTS) for Ad-hoc network based on link queue, alternate node and ferry transmission. This kind of scheme has good performance on building link Ad-hoc network, data drop rate, average throughput of network.

Abstract: The detection of buried targets in shallow water is a tough task in the presence of sea-bottom reverberation. Because both target echo and reverberation are caused by the transmitted signal, they are mixed together in both time domain and frequency domain, which makes traditional signal processing methods inefficient. Blind Source Separation (BSS) is expected to isolate the reverberation from the target echo. However, the feasibility should be proved before separation. In this paper, a method based on spatial correlation is proposed to determine whether reverberation and target echo can be separated as different sources. Then, considering the nonstationarity of the reverberation, SONS (Second Order Nonstationary Source Separation) is applied to separate the original received signals. The sea experiment result shows that BSS is not only feasible but also valid to separate target echo and reverberation, and the target echo after BSS is of higher SRR which makes further process more credible.

Abstract: In order to eliminate the negative effect of temperature to automobile pressure sensor whose environment temperature changes from-40°C to 130°C, a calibration circuit is designed based on ZMD chip. The temperature characters of this pressure sensor are: zero point linearly change with temperature at the rate-0.07mV/20°C; strain coefficient linearly change with temperature at the rate 3.27e-4/°C. After calibrated, the output of pressure sensor change only with pressure and the deviation value is from-0.48%FSO to +0.84%FSO，in the designing range ±2%FSO.

Abstract: This paper presents our initial studies on comparing properties of two laser scanners. The research mainly consists of two parts: tests on measurement characteristics of laser scanners and performances of them under different environments. Through the tests on measurement characteristics, we deeply understand the measurement drift over time and measuring stability of the two scanners. From comparing their performances under different environments, we found the suited application environment for the two scanners. The conclusion from the whole research provides a support for subsequent studies on intelligent vehicles.

Abstract: Limitation of synchronizing speed is a key feature for finite time synchronization of complex networks. We studied such limitations as coupling strength tends to infinity for networks with Lorenz oscillator as nodes under conditions that nodes were coupled in different ways. It was found that if nodes are coupled by only one state variable, coupling by second variable has the highest synchronizing speed. If nodes are coupled by two state variables, coupling by second and third variables has the highest synchronizing speed. If nodes are coupled by all three variables, the limitation of synchronizing speed will approach infinity.

Abstract: As for the problem that component gas characteristic spectrum lines overlaps seriously in the identification of Mixed Gas, Support Vector Machine is introduced for the identification, and an one-by-one identification methods for Mixed Gas classification based on the binary category identification model based on the support vector machine is proposed in this article. One-by-one category identification is carried out for each mixed gas when the characteristic spectrum lines are overlapped seriously and is transformed in high dimensional space into linear by SVM kernel function transformation. In the experiment for gas component identification of a natural gas, we compare the recognition results affected by different kernel functions, data preprocessing, feature extraction, numbers of training samples and other conditions. The results show that the method has the correct recognition rate of over 97% for the natural gas whose concentration is over 1%, and it has a great promotional value both in theory and practical application.

Abstract: With the rapid development of virtual instrument technology and network technology, the networked virtual instruments appear great potential in remote measuring and diagnosing field. This paper first presents a measuring and diagnosing system for complicated electric equipments based on PXI/VXI networked virtual instruments, then analyze the architecture of the network and the hardware, software configurations. Currently, the system has been successfully implemented in a large, complicated electric equipment for measuring and diagnosing, and achieved good results.