Search

To simulate acetate consumption and electricity generation in a cycle of a microbial fuel cell (MFC) treating synthetic acetate-based wastewater with low concentration, nonelectrogenic bacteria (NEB), which had no contribution in electricity generation, was incorporated with methanogen's kinetic parameters into a previous biofilm model proposed by Marcus et al. (Biotechnol Bioeng 98:1171-1182, 2007). However, the Coulombic efficiency was estimated to be 40.1%, whereas the experiment showed 13.6%, as the presence of NEB was obviously underestimated. Thus, the maximum NEB reaction rate (q

This study investigates whether a novel estimation method based on machine learning can feasibly predict the readily biodegradable chemical oxygen demand (RB-COD) and slowly biodegradable COD (SB-COD) in municipal wastewater from the oxidation-reduction potential (ORP) data of anoxic batch experiments. Anoxic batch experiments were conducted with highly mixed liquor volatile suspended solids under different RB-COD and SB-COD conditions. As the RB-COD increased, the ORP breakpoint appeared earlier, and fermentation occurred in the interior of the activated sludge, even under anoxic conditions. Therefore, the ORP decline rates before and after the breakpoint were significantly correlated with the RB-COD and SB-COD, respectively (p 0.05). The two biodegradable CODs were estimated separately using six machine learning models: an artificial neural network (ANN), support vector regression (SVR), an ANN-based AdaBoost, a SVR-based AdaBoost, decision tree, and random forest. Against the ORP dataset, the RB-COD and SB-COD estimation correlation coefficients of SVR-based AdaBoost were 0.96 and 0.88, respectively. To identify which ORP data are useful for estimations, the ORP decline rates before and after the breakpoint were separately input as datasets to the estimation methods. All six machine learning models successfully estimated the two biodegradable CODs simultaneously with accuracies of ≥0.80 from only ORP time-series data. Sensitivity analysis using the Shapley additive explanation method demonstrated that the ORP decline rates before and after the breakpoint obviously contributed to the estimation of RB-COD and SB-COD, respectively, indicating that acquiring the ORP data with various decline rates before and after the breakpoint improved the estimations of RB-COD and SB-COD, respectively. This novel estimation method for RB-COD and SB-COD can assist the rapid control of biological wastewater treatment when the biodegradable organic matter concentration dynamically changes in influent wastewater.

A terminal aimpoint selection algorithm is proposed in this paper for selecting the aimpoint precisely in real time. This approach avoids complicated and time-consuming pattern matching or boundary extraction. Through the image preprocessing and corner detection, the convex hull technique is utilized to cover the target area based on Computation Geometry, where centriod of the convex hull is defined as the aimpoint of the target. The proposed algorithm promotes intelligence, efficiency and accuracy of navigation guidance systems, which is proved in the simulation.

The wireless channel model, which was suitable with the complex environment of battlefield, was built by analyzing the digital image of wireless transmission channel, the transmission characteristics and the fading type. The error correction of coding for the compressed code stream of image was carried out specifically with Turbo code, and the Simulink simulation model was designed. The system simulation analysis was carried out for the performance parameters that affect the Turbo code and the BER performance of as-built wireless channel model. The results showed that the Turbo code is a kind of error correction one, which is anti-fading and strong interference among codes. It can not only reach higher peak signal to noise ratio, but also transmit more steadily and more reliably in the changeable channel environment under noise interference. Furthermore, the turbo can be applied for code correction and controlling.

In order to improve the degree and real-time of the vehicle image detection, a background extraction method based on the probability mean value method and the background update based on the weighted coefficient method through divided area are proposed through the acquisition of real-time traffic information and processing of video images for intelligent transportation systems. Finally a prototype of background extraction and background update is got, and it achieves the detection of moving vehicles. The experimental results show that this method is simple, small amount of calculation and it has a good robustness; it can extract a good background image quickly and detect a complete shadow of vehicles. So this method can meet the requirements of real-time detection of multiple moving targets.

To get accurate frequency information from doppler signal is very difficult. In order to improve accuracy of doppler radio fuze, a design scheme which is not only using doppler signal amplitude information but also using doppler frequency information, and comprehensive and these two aspects of information give out the fuze work distance. The solution we give out in this paper is that we realize the STFT by application of parallel process mass on FPGA and together with quick frequency selection mechanism. Then we could get the frequency information from the doppler signal. Test results show that by using short time window Fourier transform, we could realize time-frequency analysis of doppler signal in allow system time delay.

The giant magneto-impedance (GMI) effect of amorphous wire and its affecting factors were analyzed. Magnetic impedance (MI) element was designed with a special structure. So the difficulties of complex negative feedback circuit and winding double circuits on amorphous wire were solved. High frequency current pulse generator, signal preprocessing circuit and digital signal processing module were designed. Thus a low magnetic field detector was realized. The sensor and the detector were tested in laboratory. The experiment results proved that the sensor had good linearity at the magnetic field range from -3 Oe to +3 Oe. The sensitivity reached 65 mv/Oe and the sensor had well temperature stability. The magnetic field resolution can reach 50 μOe and small magnetic target can be detected.

In-depth analysis of the characteristics of the battlefield on the basis of ferromagnetic targets, according to the problems of magnetic fuse detection system, such as low detection resolution and poor status of target recognition, the new type of magnetic sensors based on Giant Magneto-Impedance(GMI) effect, because of the sensitivity, power consumption, etc. natural advantages, with its fuse detection system for the magnetic core components, combined with fuzzy neural networks, can guarantee that probe nano-Tesla(nT) accurately identify the target within the scope. Then, equable magnetization rotation elliptic is used to simulate the tank and military truck, taking the magnetic moments and semi-focal length, that are Mx, My, Mz and c, as recognition characteristic quantity, and the FNN is used to recognize the tank and military truck including the categories and motion directions. The method achieved good recognition results through experimental verification, and it has great significance to improve detection range and recognition accuracy.

The structure and aerodynamic performance of inlet pipe which is the key component of turbine generator have direct and significant influences on the input characteristic and safety reliability of fuze turbine generator. A kind of inlet pipe structure was designed by applying the variable cross section pipe and simulated based on the inlet pipe type and application analysis of turbine generator. The results showed that the air flow pressure which the turbine generator obtained from the ballistic can be controlled in a certain range by adjusting the relative structure parameters of inlet pipe to guarantee the stable output characteristics of generator, which can completely meet the technical requirements of fuze.

Aiming at the movement characteristics of trajectory correction projectile, the characteristics, installation configuration and error processing algorithm of gyroscope free strapdown equipment were analyzed for gyroscope free strapdown inertial navigation measurement unit(GFSINMU) by utilizing “current” statistical model combined with the outliers processing method. The results showed that the cumulative errors of GFSINMU can be decreased in a certain range by selecting the installation method of accelerometer and utilizing reasonable error analysis method. Thereby, the measurement accuracy of adjusting GFSINMU can be increased, which can adapt to inertial navigation calculation of high dynamic command correction projectile.

Magnetic detection and localization is becoming a hot point in the past twenty years. Amorphous wire is a promising material to produce high performance magnetic sensor for GMI effect. A high sensitivity micro magnetic sensor is designed and a processing circuit is presented in this paper. Based on the processor TMS320F28335, the magnetic signal of ferromagnetic target can be sampled and processed.

Image segmentation is an important technique for image processing and computer vision. The principles of 1-D Otsu’s algorithm and thresholding through index of fuzziness are described. Since the infrared images of tank have low object-background contrasts and blurred boundaries in the complex background condition, an adaptive algorithm for image thresholding through index of fuzziness, which is combined with the spatial correlative information, is proposed. The new method makes full use of the spatial correlation of pixels, so that it can extract the detail of the image from the complex background effectively, and improve the accuracy of the segmentation. The results of experiments prove that the presented algorithm has better performance and better robustness against noise.

Laser imaging techniques have advantages for EMI (Electro Magnetic Interference) immunity and abundant image information. This contribution describes the research activity on the scannerless laser imaging detection technique using direct detection aimed at laser fuze applications. The technique using a pulsed laser to illuminate the target and a focal plane array can be used as a receiver. The range information is achieved by means of a direct time of light measurement. Information about the reflectivity of the target is gathered by recording the amplitude of the received pulse. In this paper a high-repetition-frequency, narrow pulse semiconductor laser floodlight emitting system is designed; corresponding optics is used to generate the homogenously illuminated FOI (field of illumination). The echo of laser is collected by receiving optical system fed to focal plane array. Some experiments were done with the emitting and receiving systems that had been designed. Experiments show the validity and rationality of this method. The scannerless structure is robust and provides instantaneous snapshot-type imaging. Avoiding any moving mechanical parts, scannerless laser imaging system have distinct characteristics such as small, compact, high frame rate, wide field of view and high reliability. It is an optimal approach to realize laser imaging fuze.

Ballistic missile defense system (BMDS) is a weapon system for intercepting enemy ballistic missiles. It includes ballistic-missile warning system, target discrimination system, anti-ballistic-missile guidance systems, and command-control communication system. Infrared imaging detection and laser imaging detection are widely used in BMDS for surveillance, target detection, target tracking, and target discrimination. Based on a comprehensive review of the application of target-detection techniques in the missile defense system, including infrared focal plane arrays (IRFPA), ground-based radar detection technology, 3-dimensional imaging laser radar with a photon counting avalanche photodiode (APD) arrays and microchip laser, this paper focuses on the infrared and laser imaging detection techniques in missile defense system, as well as the trends for their future development.

Unattended laser target designator (ULTD) was designed to partly take the place of conventional LTDs for accurate positioning and laser marking. Analyzed the precision, accuracy and errors of acoustic sensor array, the requirements of laser generator, and the technology of image analysis and tracking, the major system modules were determined. The target’s classification, velocity and position can be measured by sensors, and then coded laser beam will be emitted intelligently to mark the excellent position at the excellent time. The conclusion shows that, ULTD can not only avoid security threats, be deployed massively, and accomplish battle damage assessment (BDA), but also be fit for information-based warfare. Keywords: information process, unattended ground sensor , laser target designato r, accurate positioning 1. INTRODUCTION Nowadays semi-active laser (SAL) guided munitions are of prime importance to accomplish precision strike pinpoint targets, the man-in-the-loop mode is very useful to achieve target recognition, intelligent control, and battle damage assessment (BDA). For SAL guided munitions, the laser target designator (LTD) is absolutely necessary. The munitions have an internal semi-active guidance system that detects laser energy and guides the weapon to the target illuminated by an external LTD. Before the munition exploded, about 10 s econds, LTD radiate a narrow beam of pulsed energy in the infrared wavelength spectrum, that are semi-active illuminators used to tag the desired spot. These can be aimed such that laser energy precisely designates the chosen spot on the target. LTDs can be located in the delivery aircraft, another aircraft or on a ground source. But the obvious shortcoming of this battle mode is LTDs must be carried by platforms which are controlled by soldiers, that means we have to invade opponent fire range to mark our targets and to face to titanic threats all the time. So, a novel unattended laser target designator (ULTD) was design ed to solve this problem partly; and we trust it is fit in with the foreseeable future information-based warfare. The previous work includes argumentation, system design, modular design and application analysis , they will be discussed as follows. 1.1 Existing threats With the development of components and parts, integrated circuit, new approaches and correlation techniques, precision strike weapons were improving rapidly in the past years. On one hand, it is an available method to damage pinpoint targets, hard targets and armored targets effectively; on the other hand, minimum collateral damage must be considered in earnest, especially in urban warfare, anti-terrorist war and asymmetric warfare situations, which may be the major patterns of battle in the future. The conventional guided munitions always cause serious additional damage to ordinary people. From the several anti-terrorist wars, underground cave s, buildings in urban and moving vehicles were becoming the major targets; actually most of which were destroyed by precision guided munitions. At the same time, the opponents use a variety of means to protect high-value targets, including full spectrum obstruction, decoy target, underground command center, armored layer, etc. To follow the two factors mentioned before, the circular error probable (CEP) of modern precision munitions are requested to be 3m or lower, SAL guidance and combined guidance based on it will be the suitable selection. Normally, the effective range of portable LTDs is 3km~5km, and the airborne is more than 10km for tanks. For this reason, most of the munitions can not be launched safely; th e carriers and LTD operators must notice the counterattack.

A line imaging ladar sensor using linear diode laser array and linear avalanche photodiode (APD) array is developed for precise terminal guidance and intelligent proximity fuzing applications. The detection principle of line imaging ladar is discussed in detail, and design method of the line imaging ladar sensor system is given. Taking military tank target as example, simulated tank height and intensity images are obtained by the line imaging ladar simulation system. The subsystems of line imaging ladar sensor including transmitter and receiver are designed. Multi-pulse coherent algorithm and correlation detection method are adopted to improve the SNR of echo and to estimate time-of-flight, respectively. Experiment results show that the power SNR can be improved by N (number of coherent average) times and the maximum range error is 0.25 m. A few of joint transform correlation (JTC) techniques are discussed to improve noncooperative target recognition capability in height image with complex background. Simulation results show that binary JTC, non-zero-order modified fringe-adjusted JTC and non-zero-order amplitude-modulated JTC can improve the target recognition performance effectively.

This paper presents that software radio technique is applied to laser target detection system with the pseudo-random code modulation. Based on the theory of software radio, the basic framework of the system, hardware platform, and the implementation of the software system are detailed. Also, the block diagram of the system, DSP circuit, block diagram of the pseudo-random code generator, and soft flow diagram of signal processing are designed. Experimental results have shown that the application of software radio technique provides a novel method to realize the modularization, miniaturization and intelligence of the laser target detection system, and the upgrade and improvement of the system will become simpler, more convenient, and cheaper.

The standard detecting model of the laser radar is given, and the forms of the detecting model for different detecting conditions are analyzed at first. On the base of foregoing analyses, the detecting range models reflecting the main parameters relationship of the laser detector are set up. On the other hand, the detection probability and the false probability are the important indices of overall design for the laser detector, and they are also the important parameters for appraising the reliability of the laser detector. So the mathematical models reflecting the interaction relationship of the detection probability, the false probability, the single-noise ratio and the detecting threshold value are built at the same time, and the Monte Carlo method is adopted to simulate the statistic distributed rules of the detection probabilities, the false probabilities, the single-noise ratio and the detecting threshold values for the laser detector based on the pulse system and the pseudorandom code system. The simulation results show that the ability of the laser detector using pseudorandom code system is better than that using single pulse system. It is proved by design and experiments that the theoretic foundations are provided by the range models and the simulation results for designing scientifically the laser detector.