Search

In the e-procurement platform system, all parties involved in the transaction must not deny their behavior, and a reliable time stamp of the transaction is required to solve a series of business and legal issues. Because it is relatively simple to change the user’s desktop time, the time is not highly reliable. Therefore, it is necessary to provide a time stamp service with a high degree of trust and non-repudiation. The time stamp system binds the confirmed time with specific electronic data, so ensuring node clock synchronization is the basis of fairness in the procurement platform. However, in practical applications, due to the limitations of various factors in wireless networks[1], the performance of clock synchronization will be affected[2]. This article will focus on the influence of noise in wireless networks on clock synchronization and study the observed discrete noise- containing data. Perform Kalman filtering, establish a clock synchronization state space model, and implement a deviation correction for the unbiased optimal estimation of the system deployment. Finally, a 6-node tree and star system are used to perform error correction comparisons to verify the effectiveness of the algorithm.

Cable-driven parallel robots (CDPRs) have attracted extensive attentions in the past few years due to their advantages in both the large workspace and the large payload capacity. Furthermore, CDPRs have potential in reconfiguration. In this research, a re-configurable CDPR is presented, and its modular design is detailed. Then, kinematics of the proposed CDPR is analyzed including the inverse and direct kinematics. Based on the kinematic model, simulation validations are made by using two kinds of trajectories, i.e. a line and a circle. Finally, prototypes are built and preliminary experiments are made, including the alphabetic writing and the Chinese character writing tests. Results show that the performance of the robot is good, which further validates the kinematic modeling and modular design of the proposed reconfigurable CDPR.

For mixed storage with lithium battery and super capacitor energy system, proposed a coordinated control strategy based on state. According to the state of charge and discharge of battery lithium adjusted for super capacitor SOC, Two kinds of storage and coordinate the cooperation in the protection and restriction, combined with the transient simulation model and general steady-state model, analysis in the energy storage system can run mixed storage redundancy configuration condition, compared with the existing control strategy, and analysis the influence strategies on control effect through the operation curve.

The parameters in the control strategy of hybrid energy storage system have certain influences on the control effect, so, quantitative analysis should be performed to optimize the parameters. This paper which is based on the state of the lithium battery charge and discharge control strategy based on hybrid energy storage system has put forward the super capacitor energy storage charged state response margin index and coordination by considering the self-discharge rate and affecting factors, such as charge and discharge efficiency of energy storage system mathematical model. At the same time, this paper has established a hybrid energy storage system based on lithium battery life of quantitative coordination control parameter optimization model in combination with irregular which is suitable for the practical application of the charging and discharging lithium battery life quantitative model. Through example analysis, it shows that the reasonable choice hybrid energy storage system coordination control parameter can prolong the service life of the lithium battery, and thus improving the overall performance of the hybrid energy storage system.

Active distribution network is an effective way to realize the integration of distributed new energy sources in the future. This paper focuses on the coordinated control framework of multi-time scales distributed generation for active distribution network under normal operating conditions, including scales for a long time in active distribution network the optimization control and short time scaleactive distribution network of regional autonomy for control. On this basis, a global optimization algorithm based on optimal power flow is proposed, and a regional autonomous control algorithm for active power distribution network based on power control error is proposed. Through simulation examples to verify the time of active distribution network coordinated control technology of self tendency ute and for the effectiveness of real-time scheduling of distribution network active.

The hybrid FDTD algorithm is proposed for long-range Loran-C ground-wave propagation prediction, especially for the complex path. In this paper, the computational domain is divided into two parts, the ordinary FDTD method with fine-grid and higher-order FDTD with coarse-grid are combined for the prediction. The subgrid technique is introduced to analyze and transfer the electromagnetic fields of different domain. The results show that the proposed algorithm improves computational efficiency greatly while maintaining comparable accuracy with the traditional FDTD using high-grid resolution.

With the developing of distributed clean energy in Photovoltaic and Energy Storage concentrated areas, the lower voltage quality has become a major problem of the distribution network right now. With regard with the lower voltage problem ofPhotovoltaic and Energy Storage concentrated areas, this paper from the perspective of the active distribution network, conducts sensitivityanalysis for reactive power and active power of the radiation distribution network. On the basis of the sensitivity analysis, thebest position to set storage elements is determined and the novel voltage regulation strategy based on the combination of distributed power and on-load tap changer (OLTC) regulator is proposed. Finally, this paper uses numerical examples to verify its effectiveness. The result proves that the integrated regulation means of active distribution network can greatlyimprove penetration levels of distributed generation without the use of specialized reactive power compensation device.

Distributed PV storage micro grid, which is composed of photovoltaic energy storage and distributed energy and load, not only can effectively use the distributed photovoltaic power supply, but also can improve the power supply reliability level and the energy utilization rate of power system. In order to effectively utilize the distributed photovoltaic power generation, the control strategy of the power grid with distributed optical storage system is studied. To establish the model of each component of the optical micro grid system, the modeling of the control system includes maximum power point tracking control, battery charge and discharge control and inverter power factor control. Application of improved BP neural network algorithm to build short-term forecasting model of power generation. On the basis of the various components of the optical micro grid system, the simulation model of optical micro grid system is built, and the simulation research is carried out on the control of the optical micro grid system under different scheduling strategies.

To improve the harmonic current compensation performance of the active power filter (APF) and reduce its active part ratting, a hybrid active power filter (HAPF) of a lower dc bus voltage is studied, which composes of a passive filter and an active power filter in series. On the basis of mathematical model which includes both the passive filter and an active power filter, a Lyapunov function is constructed, and then an appropriate control law is presented to make its leading function negative definite, so that the steady tracking for harmonic current is realized. The turning range and the optimization goal of the control gain are also given by derivation from the robustness and tracking performance perspective. At last, the simulation analysis and experiment verify the feasibility and the superiority of the proposed control strategy.

Serious overloaded transportation phenomenon exists generally in China. It causes tremendous threat to road traffic safety. Current situation of overloaded and its influence on traffic safety are analyzed in Yu-Chang expressway. Proposals are presented about how to reduce traffic accidents caused by overloaded transportation.

With the development of information technology and high technology innovation, human-computer interaction design is also constantly updated. The rapid development of Intelligence technology shows that the direction of human-computer interaction design is natural interaction that man and machine in great harmony. User-centered design of human-computer interaction will be the ultimate goal. It will effectively help users to complete tasks and make users satisfied during the process.

In this paper, according to the problems existing in current network teaching and the characteristics of intelligent network teaching, network teaching system based on web services is built to support intelligent and cooperative teaching. Intelligent network teaching system is developed which integrates teaching link and teaching management process, and comprehensive analysis is made for the component modules and system function. In addition, the implementation technique is discussed.

Based on node influence, establishes a maximum spread model of single-source influence, defines concepts related to maximum spread of single-source influence, proposes the polynomial time algorithm of maximum influence on single-source, quantifies the largest node set influenced by single-source, computes the most influential node in a social network. Our algorithms significantly out-perform node selection heuristics based on the well-studied notions of degree centrality and distance centrality from the field of social networks. Our framework suggests a special approach for reasoning about the performance guarantees of algorithms for this type of influence problems in social networks. Typical applications show that the optimization problem of selecting the most influential node on single-source has an important practical value.

Average strain of cell of certain length can be measured by long-gauge Fiber Bragg Grating sensors. This article, taking average flexural rigidity of cell EI based on average strain of cell and wide average height of neutral axis of cell Z as damage identification parameters, validates via multiple damage numerical simulation of I-shaped cantilever steel beams and simple-supported steel beams, and proves that structural static multiple damage identification method based on average strain of cell is feasible.

Since the computer and internet were introduced, the time and spatial barriers have been broken by message conveying, and the amount and the speed of information has been increased than before. The aim of information visualization is to convey complex information to the audience more effectively,and visual perception-based interface is considered as the most effective medium for information dissemination. In this essay, through discussion and further understanding of application of human-computer interactive in visualized information design, we clarify the human-oriented theory of interface design and apply it in the whole process of interface design.

In the distributed network environment, delegation is increasingly necessary, so a delegation model based on UCON and Dynamic Fuzzy-Neural-Network (UCONDFNND) is proposed. The model considers the delegation and the credibility. The delegation solves scalability problem of distributed authorization, such as distracted implementation of a task. The delegation based on UCON makes the process of access control with dynamicity, intelligence and security, so it adapts to the need of distributed network. The credibility, which is introduced into UCON, can effectively control the size of rights and make the authorization process flexible. It is accurate and intelligent that the model uses Dynamic Fuzzy-Neural-Network to calculate credibility. This arithmetic not only has strong reasoning ability, but also has good robustness. And the self-learning mechanism of neural network enhances the adaptive function of network.

As the potential of Loran-C in land vehicle tracking, and in marine and aeronautical navigation explored, the importance of employing accurate values of additional secondary factors (ASFs) is increasingly being recognized. A computer method that used to generate ASFs for irregular terrain is developed. In order to determine the prediction accuracy of the method in irregular terrain, during the summer of 2005, a series of tests were conducted in the selected area in Jiangxi Province. Using the set of ASF values obtained by the method above, the time delay correction errors of ground-wave propagation are reduced to less than 200 ns in the land.