An Application of Continuation Method for Electrical Impedance Tomography in Brain Hematoma Case

It is a significative attempt in medical diagnosis that Electrical Impedance Tomography is used to hematoma monitoring. Since there is great difference in physiological parameters among different persons, among varieties of ill cases, and different tissues, it is important to loosen the limits of initial values of reconstruction algorithm. A new approach named Continuation method is proposed in Electrical Impedance Tomography. In addition, simulating calculation results are given to validate the approach effective.     

The Open Software System for Electrical Impedance Computed Tomography

The components of open software system for Electrical Impedance Computed Tomography and their functions under Windows environment are introduced, and the ways to extend system's functions are given.     

Design of converter of DC-AC type contactless power transfer system

A new type of circuit topology for DC-AC type contactless power transfer(CPT) system is proposed, and the asymmetric DC-AC convert is used to imply the new topology. The topology simplifies the circuit and control of DC-AC type CPT system, reduces the power loss of power conversion of secondary circuit, and improves the overall efficiency and power density of the system. This paper presents the topology of the converter and investigated its control strategy. A model of the system has been derived, with which the system is simulated and studied. The measured experimental results have verified the theoretical and simulation results.     

Evolutionary topology optimization of the lower stable of a hydraulic press

It is difficult to obtain the globe optimum solution by applying conventional sizing and geometrical optimization methods. Evolutionary topology optimization is conducted for the lower stable of a hydraulic press using a bi directional evolutionary structure optimization (BESO) method based on ratio of stress changes, and the evolutionary history and index are analyzed. The presented algorithm obtains the simultaneous optimization on both geometry and topology, and a new topology of the lower stable of the press is evolved which possesses a reasonable topological structure. The results of finite element analysis show that the new structure has decreased maximum stress, uniform stress distribution and good material usage.     

Reliability evaluation algorithm for complex electrical distribution networks using the storage structure of adjacency multilist

A section algorithm of reliability evaluation for complex medium voltage Electrical Distribution Networks (EDNs) using adjacency multilist (AM) is proposed. The constructing method for AM is introduced. The AM can be used to store the structure data of EDNs and to solve the problem of space & time complexity. A new power flow algorithm of backward / forward sweep is proposed and a fast algorithm of forming sections in distribution network is put forward. The proposed algorithm makes a perfect combination of the power flow algorithm and the section algorithm of reliability evaluation, which makes efforts to decrease the work of programming and saves the computing time. Applying the proposed algorithm in RBTS-BUS6 system and actual EDNs, the reliability assessment results show that the algorithm has an advantage of saving time and possesses efficiency in engineering practicality.     

Parameter design and simulation for animproved direct current side active power filter

Considering the characteristics of the dc side series active power filter (APF) that the output voltage cannot be adjusted and the control circuit is complex , an improved single phase dc series APF topology is proposed. The improvement of the new circuit topology and fundamental working principle are analyzed. Following the circuit power factor pre regulator principle, the designing method for the main circuit parameters is given. The voltage ring and the current ring are designed by using the zero pole method. The main circuit power switch is controlled with the same frequencies, while the control circuit was simplified further. Compared with the paralleled APF, the main circuit of topology structure is simplified and the number of the active switches is reduced, which show low input current harmonics, high power factor, large voltage output adjustment range and low cost. The simulation results prove that the proposed topology is correct and reliable.     

Topology optimization for constrained layerdamping material in structures using ESO method

Topology optimization for constrained damping material in structures is investigated in order to suppress structural vibration through the optimal placement of constrained damping material in structure. A mathematical model to describe the topology optimization problem is established. In the topology optimization approach, structural modal damping ratio is designed as objection function, while constrained damping material consumption is considered as constraint condition. The sensitivity of modal damping ratio to the place is analyzed. An evolutionary criterion for placement of constrained damping material in a structure is presented. The formula of sensitivity is derived and used to determine the optimized placement of constrained damping material in structure. The topology optimization problem is further solved by evolutionary structural optimization (ESO) method. The numerical examples are given. The results show that a stable and dramatic increase of the modal damping ratio during the course of iterations can be observed. Therefore, an optimal layout of constrained damping material in structure is obtained. The comparison of amplitude frequency characteristics with the optimal and fully covered layout validates the effectiveness of proposed topology optimized approach.     

High speed, high precision digital phase sensitive detector design for electrical impedance tomography

Electrical impedance tomography (EIT) system must have the properties of high precision and speed, thus the digital phase sensitive detector (DPSD) based on the field programmable gate array(FPGA) is developed for data collection of EIT. Based on the principle of DPSD, the relationship between signal to noise ratio (SNR) and sample resolution as well as total number of samples is deduced. An implementation scheme of this system and a method of designing analog to digital converter (ADC) clock based on direct digital synthesis (DDS) technology are provided. The system adopts high speed multi channel ADC and low jitter clock conditioner for ADC. Real time DPSD is implemented with FPGA. The experiments show that the measurement accuracy reaches 0.03% and the SNR reaches 85 dB. The agar phantom experiments prove that the performance of the DPSD meet the designing requirement for EIT.     

Relationship Between Electrical Property and Microstructure of Mineral Admixtures-Cement Paste

The electrical properties of fly ash, slag and limestone powder-cement paste were studied by the methods of Cyclic Voltammetry and AC Impedance Spectroscopy. The results of electrical test were fitted by equivalent circuit. The correlations between electrical parameters of paste and unevaporable water content, pore structure by mercury porosimetry were compared. The results show that there is a positive relation between the unevaporable water content and the electrical resistivity of paste. If the unevaporable water content is higher, the hydration degree is higher and the electrical resistivity of paste is higher. The electrical resistivity of paste is increased with fly ash and slag, and it is unaffected with limestone powder of 5% dosage. The resistance Rs of pore solution of paste is increased with the prolongation of hydration, and the changes of resistance Rs and the electrical resistivity are unanimous. The resistance Rp and electrical capacitance C of gel are related to C-S-H content, and there is a negative relation between the resistance Rp and electrical capacitance C of gel. The complexity of pore structure of paste is increased with the prolongation of hydration. The constant phase angle exponent P by AC Impedance Spectroscopy is decreased and the value of fractal dimension by mercury porosimetry is increased.     

The research in processing fMRI data using temporal-spatial model based on CCA

In the analysis of cognition of human brain,the fMRI is often used.Corelation is a common method in fMRI data detecting,but its ability should be improved.Based on the Canonical Correlation Analysis(CCA),the temporal correlation and spatial correlation are used together to detect the activated area in the fMRI data.By the application of the method in simulation data and fMRI data,it shows that this method is effective in the detecting.     

CALCULATING APPROACH FOR SOLVING LARGE-SCALE POWER SYSTE WITH TOPOLOGY AND PARAMETER GHANGES

A straightforward and unified approach for solving the large-scale, faulted power systems is presented in this paper. In contrast .with conventional algorithms, the various changes of topology and impedance of the systems and its boundary conditions of fault can be handled flexibility and effectively in one-step procedure by proposed method, and it is convenient to choose the computational procedure more resonable according to the situation of power systems. One of the noteworthy features of the proposed method is the natural manner to handle mutual effects, and it is easy to design programs. The calculating technique for easy-to-program is given in this paper. It shows that effectiveness of calculating large-scale faulte power systems with topology and impedance changes by the modified current sources.     

面向植物生长智能监控的叶颜色特征提取

根据植物生长智能监控的需求,设计了叶颜色特征提取方法：首先提取叶整体颜色特征,根据特征数据能够判断植物叶是健康、存在整体颜色变异还是存在局部颜色变异;如果存在局部颜色变异,进行局部颜色变异部分分割、颜色特征提取和空间分布特征提取。将一组具有不同程度颜色变异的植物叶的阳面和阴面图像作为两个系列进行了对比测试。测试数据表明：特征参数能够区分健康的叶和存在变异的叶,能够区分不同类型和不同程度的颜色变异,能够为后续决策处理提供数据支持,特征提取方法适合植物生长智能监控。     

The edge element method in the forward problem of magnetic inductiontomography with homogeneous sinusoidal magnetic excitation

The edge finite element method and the imaging visualization have been studied in the forward problem of magnetic induction tomography MIT with homogeneous sinusoidal magnetic excitation. The definite equations of the forward problem were established using the electric field intensity as the vector variable. The edge FE method for solving the definite equations was introduced in detail and realized as the MATLAB program. In order to realize the visualization of MIT in imaging the intracranial hemorrhage, a real human brain finite element model was created with the human head MRI data. On the basis of this model, we realized the 3D visualization of MIT imaging in MATLAB. The research results demonstrated the validity of the definite equations and the edge FE method in calculating the forward problem. And the 3D visualization of MIT imaging with real human brain model established a foundation for the application study of MIT in imaging intracranial hemorrhage.     

社会网络分析法在城镇工程基础设施健康评价中的应用

针对工程性基础设施网络拓扑结构不合理导致的全局性破坏问题,将社会网络分析(SNA)方法的密度、凝聚子群、K-核、Lambda集合、切点和中心度等计算概念引入基础设施网络拓扑结构评价,提出了由网络完备度、层级边关联度、局部稳定成份比例、节点脆弱性、荷载运行均衡度等指标构成的评价体系。通过对重庆长寿城区的电力基础设施实例研究发现,社会网络分析方法能够对设施网络拓扑结构与电网运行过程中的稳定性进行客观评价,能够找出电网过载点、对设施网络拓扑结构的紧凑程度和完整程度进行评价以及对网络整体的性能做出评价。     

An improved HEED clustering algorithm for Wireless Sensor Network

In wireless sensor network, routing protocols which based on clustering have the advantages of energy consumption, topology management and data fusion. The HEED protocol, which generates cluster heads based on distributed algorithm, drives up the rate of clustering and creates well distributed cluster heads. However, it does not consider the mobility of nodes in the network. When the distance between neighbor nodes has changed, the AMRP method which decides the node belongs to different cluster heads would cause problems such as high energy consumption, short lifetime of network and so on. Responding to these problems, the paper proposes the S HEED, a clustering algorithm based on stability, which chooses the stability as a parameter of nodes when choosing a cluster head. With S HEED algorithm, the high energy consumption problem among cluster nodes and cluster heads caused by the mobility is tackled. The simulation experiment demonstrates that the S HEED algorithm lower the energy consumption of cluster heads and prolongs the network lifetime.     

Research Methods of Brain-computer Interface Technology

Brain computer interface(BCI) is an EEG based communication and control system between human and computer or other electric devices, which does not depend on the brain's normal output channels of peripheral nerves and muscles. It is a novel kind of human interface, may have applications in rehabilitation, control and other fields. The developming speed of brain computer research in recent years is high. Methods of how to use P300, SSVEP, ERS/ERD, SCP, spontaneous EEG and implanted electrode to realize BCI are introduced. Characteristic and limitation of different methods are discussed. Status, problems and application prospects of BCI technology are also included.     

Dynamic Imaging for 3 - D Brain Hematoma

Based on disturbance method of electrical current field, numerical calculation about dynamic imaging for brain hematomas have been studied on a 3 - D sphere model. With current injected, we have found the law of the brain boundary potentials'change while the volume of brain hematoma changed. Some studies about the effect of brain skull with poor electrical conductivity to the brain boundary potentials. The results show that we can know the change of brain hematomas in terms of the measurement for the change of boundary potentials. The injected current can penetrate through the skull. These results are valuable to help doctor to accurately diagnose the brain hematoma and realize the noninvasive monitoring the brain hematoma.     

Image Watermarking Technique Based on the DCT Transform and the Edge Detection

As a main application of information hiding technique to multimedia copyright protection, the digital watermarking technique, which embeds an invisible signal (watermark) to the original multimedia data (image, audio, and video), has been proposed as a viable solution for the copyright protection and authentication of multimedia data in a networked environment since it makes it possible to identify the author, owner, distributor or authorized consumer of multimedia data. So it has drawn extensive attention in recent years and has been widely applied. A new image watermarking scheme is proposed by incorporating the DCT transform and an edge detection technique. Experimental results show that this method is more robust against the common signal processing attacks than the traditional Cox's method.     

Power transfer regulation mode for current fed CPT system

For the drawback of the power regulation in the existing current fed CPT system, a novel circuit topology and control method is presented, which can realize either Buck or Boost mode and can extend the power regulation scope. The improved topology is modeled, while the relations between the duty cycle and the output power for the two modes are derived for system analysis and design. Simulink and PLECS are used to simulate the PP type CPT system. The simulation results prove the theory analysis.     

A dual-boost three-phase DC link active power filter based on coupled impedance

A three-phase DC link active power filter (APF)based on coupled impedance and its control strategy are proposed in order to eliminate the input current harmonics of the three-phase diode rectifier. The presented APF is composed of impedance network and two asymmetric dual Boost converters. Average current control is adopted to control the DC link APF. The switch signals of the two asymmetric Boost converters are obtained respectively by leading and trailing edge modulation methods. Compared with the normal DC link active power filter,this topology reduces an active switch and a capacitance. So it can reduce costs,and there is no voltage imbalance in the DC link. Simulation results verify the correctness of the proposed topology and the corresponding control method.