A video monitoring scheme of video was proposed under a heterogeneous network, which included a network condition evaluation method and a video coding method under network with adjustable parameters. Firstly, a model of the video monitoring system for the south-to-north water diversion project under heterogeneous network was proposed. Secondly, a network parameters evaluating method based on the real-time transport protocol/real-time transport control protocol (RTP/RTCP) was presented to improve video coding efficiency with adjustable parameters. Finally, the performance of the video monitoring scheme was proved by the system deployed in the middle route of south-to-north water diversion project. The performance of the video coding in current bandwidth and the video transmission efficiency were improved under heterogeneous network. The video monitoring system met the design requirements of four channel 720P video monitoring.

To address security challenges in software defined networking (SDN) architecture, centered on the security audit aspect of the SDN architecture, the traditional network security audit solutions and the SDN architecture’s centralized control features were combined. A security audit system was designed and implemented based on the Floodlight controller and was operated in the SDN environment, in which the collection, analysis, storage of audit events and other functions were included. A backtracking algorithm against DDoS scenario was designed to detect the attackers and dummy hosts via reviewing and analyzing security audit events retrospectively. Besides, a sliding window segmentation algorithm was proposed which extracted user’s behavior patterns after implementing sequence analysis against security audit events. Based on the Levenshtein algorithm to the similarity of sequence patterns were calculated, then according to the similarity of the current user’s behaviors and historical behaviors, suspected attack behaviors were detected.

Ultrasonic guided waves have been widely applied to the defect inspection of typical waveguide structures including plates and pipes because of their large area inspection capability and high efficiency. As one type of the transducer for ultrasonic guided waves inspection, electromagnetic acoustic transducers (EMAT) attracted wide attention and got rapid development. In this paper, the research progress of EMAT for ultrasonic guided waves inspection in the past twenty years was reviewed. Main contents include the following aspects: the structural design of the single-mode EMAT used in the ultrasonic guided waves inspection of plate-like and pipe structures; the configuration parameters optimization design of coil and magnet for improving the energy and the purity of guided wave modes, the configuration design of new type patch EMAT for non-metallic materials; and the application of array technique on the EMAT performance optimization and defect localization and imaging.

Taking certain CNC camshaft grinder as the subject, its motion error analysis and modeling were studied. The movement forms and types of errors between the moving parts were analyzed, the movement between coordinate systems of the adjacent bodies was used to express the movement between the two adjacent bodies, and the ideal motion equation and actual motion equation in case of errors between the adjacent bodies were set up. Actual motion equation between adjacent bodies was made and further extended to analyze arbitrary low-order body arrays, which provides a theoretical basis for studying the multi-branch CNC camshaft grinding machine error modeling. Complex multi-branch chain CNC camshaft grinder simplified was made as a simple multibody system, and corresponding body coordinate systems and motion reference coordinate systems for moving parts were established to calculate the corresponding transformation matrix between adjacent bodies. Moving parts of the machine were divided into “workpieces-bed” and “wheel-bed” two kinematic chains. The precision constraint equation of the machine is P_w=P_t in case of using errors influence, and the constraint equation was solved. It provides necessary conditions for study of CNC camshaft grinder error compensation. Results show that the machine precision is significantly improved after error compensation.

Facing the structure design problem of fuzzy neural networks (FNNs), this paper proposed a structure design approach based on the recursive clustering and similarity methods. First, a recursive clustering method to identify FNN structure was proposed. Guided by the strength of output variations and using the recursive sub-clustering as the means, the proposed method determined the initial network structure through recursive iterations. Second, maintaining a high accuracy, the method calculated the similarity degree between each pair of fuzzy rules and then merged highly similar rules to simplify the initialized structure of the FNN. Finally, numerical experiments in function approximation and nonlinear system identification were used to verify the feasibility and effectiveness of the proposed approach.

Original online weighted sample learning tracking assumes that each sample is more independent and its contribution to the package is all the same, and the same weight is given for all the positive samples. Therefore, it does not agree with the fact that the contribution degree of the target is not all the same with the distance between the target position and the sample of package. Additionally, the original algorithm cannot accurately and comprehensively represent the sample of the target package because of single feature, thus, it affects the robustness of the algorithm. Regarding the problem of original algorithm, this paper put forward a type of visual tracking method based on weighted sample learning. The method fused HOG features and Haar features at the same time, trained a classifier under the framework of learning, and gave different weights according to the similarity of the sample features. The experiments were conducted on the image sequence of different scenarios, and compared with a variety of current mainstream algorithms. Results show that the created appearance model has higher ability to distinguish between foreground and background, the algorithm has higher accuracy and stronger adaptability and can effectively overcome the traditional sample classifier degradation problems in learning.

To solve the problems of high model dependence and low accuracy of sound source localization method based on geometric model in unstructured space, a localization method via sound-position fingerprint method was proposed. Position estimation was achieved by comparing the spatial characteristics of sound signal recorded at location point with the positioning database. The method included two stages. At the off-line sampling stage, sound signals of positioning reference nodes were obtained and the feature information was extracted to build the positioning database. While at the online stage, the real-time signal characteristics of pending sites were matched with the positioning database to accomplish the location task. Simulation results show that under the condition of sparse microphones and with large noise, the proposed localization method has rather small sound source position estimation bias, and the positioning performance can meet the demands of practical application.

To design a deep perception structure, an effective method was presented in this paper. By appropriately controlling information loss of training data, the number of neurons in each layer of a deep perception was adaptively determined by layer-wise principal component analysis (LPCA). At first, the number of input neurons and output neurons were taken as the training data dimension and the number of class labels respectively. Then, the number of neurons in the second layer was computed as a principal component analysis (PCA) dimension from the training data. Finally, the number of neurons in a layer between the second and the output layer were repeatedly computed from the activations of neurons in its previous layer followed by a PCA. Experimental results show that this LPCA method has superior performances in deep perception structure designing, such as simplifying the structure of deep perception, decreasing number of parameters, accelerating process of training, saving time for convergence. The idea of LPCA provides a new reference for designing deep perceptions and for applications.

It is very important for crowdsourcing system to analyze crowdsourcing workers’ collaborative behaviors. In this paper, the evolutionary process of crowdsourcing quality was studied based on classic hierarchically-organized mode. By establishing an evolutionary game model for crowdsourcing task collaboration among different virtual organizations, the evolutionary stability of crowdsourcing systems was analyzed and the dynamics of crowdsourcing workers’ behaviors were discussed macroscopically. The key factors affecting the evolution of crowdsourcing system, including the economic benefits, consumer utilities from completing crowdsourcing tasks and risks from insecure participating, were suggested and how the factors work was presented. All these results together provide the theory basis for designing quality control methods of crowdsourcing system.

Traditional level set method is not suitable to non-uniformly distributed human brain segmentation with complex anatomic structures and shapes. Otsu method merge with level set Chan-Vese model, leading to human brain magnetic resonance (MR) image segmentation was presented based on Level Set method. The image information of intraregional distribution was constructed by Heaviside function, and the variance information of interregional distribution was built by maximum between-class variance. In the process of image segmentation, two parts of the information were integrated each other to guide energy function evolution, and the desired results of human brain segmentation was obtained. Experiments based on two datasets that provided human brain image show that the proposed approach has obvious advantages in similarity metrics and success, and lower error rate,can perfectly complete human brain segmentation.

Subsidence induced by groundwater lowering in construction is one of the major risks in the geotechnical engineering currently, which is particularly prominent in Beijing area, whose hydrogeology is characteristized by multi-layered aquifers.In order to predict the problems accurately and conveniently,firstly, based on seepage theory and effective stress principle, the main influencing factors on the compaction of individual layers during groundwater lowering in construction through multi-layered aquifer were analyzed, and the corresponding coupled mathematical model of seepage and compression of subsidence was established. According to the principle of groundwater occurrence and movement, combined with the hydrogeological characteristics of Beijing area, a novel method to determine the bottom boundary of coupled model with major aquifer was proposed, which made the two physical & mechanical processes of seepage and compression coupled under the specific geological conditions, ensured that the that model was scientific and had engineering precision, reduced the difficulty of the actual work of analysis, and improved the practicability of the model analysis. In the aspect of specific storage value of interbed,which was an key paramerter in the model,with hydraulics of groundwater and measured data,the error and its main reason of existing calculation formula was studied, and was combined with the local experience in Beijing area. The correction formula for the specific storage of interbed was introduced, which improved the accuracy of model analysis. Finally, taking a practical project in Beijing area as an example, the detailed simulation of subsidence induced by groundwater lowering in construction through multi-layered aquifer was carried out, and the rationality of the numerical results was analyzed.

In order to study the pylon inclination’s appropriate range of single inclined pylon earth-anchored prestressed concrete (PC) cable-stayed bridge, an approximate formula about minimum inclination of pylon was obtained by the nonlinear regression analysis methods and stress analysis of inclined pylon. The equations for material amounts of the cables, anchor, main beam and pylon were derived. The approximate formula about economical inclination of pylon was obtained by introducing the cost of per unit weight or volume of each material and the relationship between the cost of the entire bridge and the factors (the inclination of pylon and the inclination of earth-anchored cables) was analyzed. Results show that firstly, as for single inclined pylon earth-anchored cable-stayed bridge, the minimum inclination of pylon increases when the inclination of side cables at main span increases, and decreases when the allowable compression stress absolute value under the action of axial force increases. Secondly, the economical inclination of pylon is influenced by the inclination of earth-anchored cables and the allowable compression stress under the action of axial force. The economical inclination of pylon increases when the inclination of earth-anchored cables and the allowable compression stress absolute value under the action of axial force decrease. Thirdly, when the inclination of earth-anchored cables is within a given range, the cost of the entire bridge initially decreases, but then turns to increase with the decline of inclination of pylon. Decreasing the inclination of earth-anchored cables is beneficial to reducing the cost of the entire bridge. Finally, the inclination of pylon should be greater than 60° and the inclination of earth-anchored cables should be greater than 43°.

In order to get more suitable hydraulic lime materials for stone and earthen historical relics reinforcement conservation, the slag, admixtures and polyvinyl alcohol fiber modified hydraulic lime mixture proportion optimization design, physical mechanical properties, mechanism of hydration hardening and durability were studied in this paper. The researches show that adding slag, admixtures and polyvinyl alcohol fiber can significantly improve the samples’ physical mechanical properties and durability. The flexural strength, compressive strength and pull strength of the modified hydraulic lime sample D had reached at 3.27, 15.45 and 0.61MPa, respectively. Moreover, after the water, salt and dry-wet cycle tests, the sample D still keeps high mechanical properties, which have important implications for conservation and restoration of the stone and earthen historical relics.

In order to modify the electrochemical properties of Si anode for lithium ion batteries, a series of porous Si/Si-Fe alloy composites with different amounts of Fe doping were prepared by magnesium reduction process. The morphology and microstructure of the as-prepared composites were investigated. The electrochemical performance of the composites as anode materials for lithium-ion batteries were evaluated by galvanostatical charge-discharge testing.The composites show a porous structure with the uniform distribution of Si-Fe alloy inside the pores and possess remarkable cycle stability with a capacity of 1133.5mA·h/g at 0.1C after 100 cycles, a capacity retention ratio of 66% and a reversible capacity of 776.9mA·h/g at 1C.

The window cracks is one of the important passageway that atmospheric fine particulate matter (PM_2.5) get through into the indoor environment and then causing the indoor personal PM_2.5 exposure. In order to evaluate the characteristics of air infiltration through the window cracks, a longitudinal monitoring regarding both indoor and outdoor PM_2.5 mass concentrations and meteorological parameters (e.g. temperature, wind speed and relative humidity) were carried out in an unoccupied office located in Beijing from September 2013 to August 2014, with the condition of no mechanical ventilation and no indoor PM_2.5 pollution sources. Additionally, a mathematical model of air infiltration rate based on a large number of measured data combined with mass conservation theorem and the method of mathematical statistics was developed. The results show that the outdoor weather conditions and atmospheric PM_2.5 concentrations is the important factor of the air infiltration rate in a room which has a certain window structure (the PM_2.5 penetration factor (P) is 0.93±0.01 and deposition rate (k) is 0.10±0.03 for the sampling site). Influenced by the change of the outdoor wind speed, the average air infiltration rate is about 0.10h^-1 at static stability days, and it is about 0.22h^-1 at gentle breeze days, as well as 0.39h^-1 at moderate breeze days.

Integrating carbon nanotubes(CNTs) into micro- and nano- devices is a critical step for applying CNTs in many fields. The high contact resistance of assembled CNTs is an important factor influencing the performance of CNT-based devices. It is possible to reduce the contact resistant of CNTs by using high temperature annealing. First, CNTs were assembled by dielectrophoresis; Second, the effects of annealing temperature, annealing time, and heating rate of reducing the contact resistance of CNTs were investigated by using orthogonal experiment design and variance analysis, and the optimal parameter combination for reducing the contact resistance was obtained; Finally, the I-V characteristic before and after annealing were measured respectively. Results show that the contact resistant of CNTs can be reduced efficiently by using high temperature annealing, and the annealing temperature is the leading factor causing the reduction of the resistance. After annealing, the contact resistance can be reduced at the most by 91.59%. The I-V curves of assembled CNTs are both linear before and after annealing.

To study the electromagnetic properties of the ferrite and the influences of the ferrite addition and the thickness of samples on the properties of the materials, foam wave absorbing materials were fabricated by introducing some ferrite and using glass and ceramic granulated material as base materials and carbon black as vesicant, with the processes of ball milling, sintering, foaming and annealing. The electromagnetic properties of ferrite had no significant change after the heat treatment at 900℃. The wave absorbing performance of materials with 5% and 10% ferrite were better than that of the materials with 15% and 20% ferrite contents, which was attributed to the fact that the incorporation of the ferrite influenced the porous structure of foam materials. Moreover, when content of ferrite was 10%, the wave absorption of the material increased with increasing samples’ thickness. The effective absorption bandwidth (reflectivity < -10dB) of 50mm thick material reached 18GHz, and its lowest reflectivity was -23.4dB.

The research progress of the laser beam welding process and the properties of joints between glass, ceramic, polymer, bulk metallic glass (bulk metallic glass, BMG) and metal were reviewed in this paper. The effects of laser welding power, welding speed, defocusing amount and the pressure on the performance of the joint were analyzed. The influence of femtosecond and nanosecond laser on the shear strength of metal-glass joints was compared with each other. The bonding mechanism and key factors influencing the reliable bonding of glass and metal, ceramic and metal & ceramic and polymer were also explored. The cracking problems of the high boron silicon glass on the surface of were solved by adding the intermediate layer. The pre-oxidation of metal surface can promote interface bonding and improve joints performance. At the same time, the weld preheat and the postweld heat treatment were adopted to reduce stress and cracks.

To improve the robustness of an estimator, based on the covariate balancing propensity score and the augmented inverse probability weighted methods, a robust estimator of the population mean was obtained for the partially linear model, when the responses were missing at random. It is proved that the proposed estimator is asymptotically normal, and hence it can be applied to constructing the confidence region of the population mean.

A model of inhomogeneous three-dimensional Navier-Stokes equations was studied in this paper. By using the energy method, Littlewood-Paley paraproduct decomposition techniques and Sobolev embedding theorem study of the global regularity of solutions were adopted. The dissipative term Δu in the classical inhomogeneous Navier-Stokes equations is replaced by -D²u and a new Navier-Stokes equations model was obtained, where D was a Fourier multiplier whose symbol is m(ξ)=|ξ|^5/4. Blow-up criterion and global regularity of this model were proved for the initial data (ρ₀,u₀)∈H^3/2+ε×H^δ, where ε and δ are arbitrary small positive constants.