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Text abstracting is widely used in search engine, text database, information filtering. In the text extraction method, the mathematical model is usually established first and extracted by the model, but this method is not effective in solving nonlinear problems. Support vector machine (SVM), based on statistical learning theory, converts a certain amount of text into vectorized training text data for extraction. This paper adopts support vector machine (SVM) to study text extraction in telecommunication field, and we obtained good results.

The trajectory tracking precision of quadrotor aircraft is affected by external interference and system parameter perturbation. In order to solve the problems, a robust control method based on improved high-order extended state observer(ESO) and block backstepping sliding mode is proposed in this paper. At first, the system model of quadrotor aircraft is divided into two subsystems of position part and attitude part. Then, the perturbations and external disturbances of the system are the uncertainty term, and an improved ESO is designed to estimate them. The estimated value is compensated timely in controller, thus the position trajectory tracking accuracy is improved efficiency. Moreover, the system structural with strong coupling characteristic, thus a robust controller is designed based on the block backstepping and sliding mode method for the attitude part. The block backstepping is contributed to solve the limitation of the traditional sliding mode method under the unmatched condition effectively, so the control attitude of the system is ensured. Meanwhile, the stability of the system is proved by Lyapunov stability theory. The simulation results demonstrate that the effectiveness of the method in this paper, and it can realize the accurate trajectory tracking for quadrotor.

Social media has been a new platform for emotion expression of individuals or groups in recent years. Millions of textual messages are constantly being generated. People with different emotion perceptions have different reactions to the same emotional event occurring in real life. However, it is hard to measure individual's emotion perception ability in both real world and social networks. This paper deals with online individual's emotion in view of complex system theory, and explores the emotion expression mechanism behind tweets. An concept of emotion bifurcation point is defined to denote the emotion perception ability and a methodological framework is proposed to measure it. Under the fundamental integration of the recognized Chinese emotion dictionaries (25,651 words included in total after reconciliation), new-born emotion words (458 in total) trained from a Sina-weibo corpus with 17 million tweets and commonly used emoticons (298 in total) as full-scale as possible, an emotion element ontology is constructed. Experimental evaluation on several certificated figures on Sina-weibo are implemented and the obtained results illustrate the reliability and validity of the proposed method.

Through the research on business network under cluster environment, the paper determines to explore the influence on SMEs entrepreneurial process within a cluster business network in order to make better use of network resources for entrepreneurial business to achieve great success. Firstly taking the cluster as the background, we describe the concept and composition of a cluster business network, then we analyze chances and resources for SMEs entrepreneurial process as well as the team concept and characteristics based on Timmons' entrepreneurial process model. Also through analyzing the influence of three main factors and processes of SMEs entrepreneurial process under different dimensions of a cluster business network, we propose the function model, expecting it can provide a reference for the SMEs entrepreneurial activities.

This paper investigates the factors which capture the cross-sectional variation in average monthly stock returns on Chinese main board A-share market from 1999 to 2010. Using univariate sorting test, univariate and multivariate cross-sectional regressions methods, we fail to find any relationship between beta and stock returns. However, our empirical result shows that there is no size effect but negative BE/ME (book-to-market equity) effect in Chinese stock market, which is different from the results of most previous researches on Chinese stock market. Additionally, liquidity in our test has the strongest power to explain the stock returns which very few researchers have ever found. Finally, we find no relationship between stock returns and E/P (earning-to-price ratio), C/P (cash flow-to-price ratio), D/P (debt-to-price ratio).

As one of the most controversial topics in international economics, the effect of the exchange rate regimes on economic performance and currency crisis is still in arguments. We find that the previous studies focus on the question without differentiating the periods. Therefore, we analyze the performance under the alternative exchange rate regime by the economic growth and inflation in steady period and the currency crisis with different developing level and exchange rate regimes. The main result include that the each exchange rate regime has its own advantage and disadvantage, and the developing level is significant in the quantity and ratio of currency crisis under the different exchange rate regimes.

In this paper, the conducted EMI paths in PWM rectifier of electromagnetic interference (EMI) in voltage source rectifier (VSR) are investigated, then a novel chaotic space vector pulse width modulation (SVPWM) scheme is applied to PWM rectifier. Such an approach uses chaotic sequence with continuous power spectrum to suppress the peaky switching harmonics, hence it fundamentally restrains EMI caused by harmonics. Compared with the conventional fixed-frequency PWM rectifier, the proposed scheme can not only significantly reduce harmonic peak of output voltage at switching frequencies, but also keep the rectifier operating performances at transient and steady state unaffected. MATLAB / SIMULINK simulation results verify the validity.

Ion-exchange membrane caustic soda technology is the most energy-saving technologies of modern Chlor-alkali, due to its best features on investment saving, lower energy consumption, pollution-free and excellent product quality. However, in its production process there have been accidents such as poison gas leak, fire and explosions, therefore risk assessment and prevention is especially important. This paper has distinguished sources of critical risks in all phases of the process, and identified their risk factors, and propose a comprehensive model with both qualitative and quantitative aspects and selected measures for the risk levels, finally, we established effective risk management and emergency plans. It is a new effective practice in China.

In this paper, the analysis, design, and implement- tation of a novel rotor position estimator for the control of switched reluctance generator(SRG) are presented. The rotor position is obtained by the improved minimal neural networks (NNs) whose inputs are the average phase current and the flux linkage. The flux linkage is calculated by flux integrator. Compared with the traditional NNs, it is demonstrated that a minimal NNs is easy to operate and attainable on a low-cost DSP. Experimental verification of the proposed control system applied to a wind energy conversion system is provided to demonstrate that the motor drive system has a small error of location observation and a good performance in generating operation. The control system of sensorless switched reluctance generator is simple, reliable and applicable to some harsh environments such as wind energy.

This paper presents a control strategy of multi-level PWM rectifier based on a novel virtual flux observer, which can control without grid voltage sensors as well as restrain harmonic and interference effectively. The conventional method has problems such as the error of amplitude, the shift of phase angle, so in the thesis two one-stage low-pass filters are adopted instead of the pure integrator in the virtual line-flux-linkage observer, which can steady the phase and amplitude. Furthermore, a novel method of voltage estimate at the three-level rectifier terminals is advanced based on the simplified SVPWM algorithm. The good dynamic and static performance under the proposed control strategy is verified by experiment.

The Internet shows more about information sharing, communication and freedom from Web to Web 2.0. However, there are challenges on the monitoring the influence structure of the negligible individuals on the web. This paper defines the “close relationship” between social individuals hidden in variety of communication medias of Internet, designs a novel intelligent association relation mining mechanism for removing the fault influence of non-valuable high frequency to improve the information quality measure of the “close relationship”; also, this paper introduces Interpretive Structural Model (ISM) to explore the power of the influence, the central figures and their close relationships, to discover the pattern and channel for information flow between the social individuals in the network. The model is suitable to relation structure mining in many kinds of networks and medias and to reveal the important relations and their influences in the virtual networks. The experiments on the original data show that the feasibility of the whole model in this paper is satisfactory.

This paper designs a framework for the new media services platform in China. By analyzing the functions of key modules, we establish an ontology semantic framework for description and organizing the heterogeneous new media resources of data, data flows, streams, and rules of the services detected from the user interactions context and node trust evaluation. Also we establish an optimal model for RSS content aggregation warehouse and the subscriber stubs warehouse. Be aimed at monitoring and analyzing the interaction pattern of users for optimal services in the platform, we put forward new service algorithms, and tested the result. Finally, we establish ontology top level description and reasoning logic metadata model for coordinating the whole system and supporting the service system at the core of all warehouses and modules. This result could provide a reference model for the new media services.

The stator-flux-oriented vector control strategy for double-fed induction motor was investigated in this paper. Three phase three-level rectifier was used as AC/DC block. This rectifier works with low harmonic distortion in the grid side. Besides, it maintains a high power factor while the energy flows in bidirectional way. For the DC/AC converter, three-level inverter was adopted. Using stator-flux oriented vector control, the double-fed induction gains a high dynamic performance when the stator side was controlled operating in a unite power factor condition. In this paper a novel simplified space vector pulse width modulation(SVPWM) method was proposed to simplify the calculation. The neutral-point potential balance can be easily realized with this method. The control strategy was verified by experiments.

This paper proposes an ontology-based information content security analysis framework, which adopts artificial intelligent system designing theory and ontology engineering method to improve information content security surveillance. This framework introduces ICSO (information content security ontology), by which we incorporate disparate and heterogeneous data sources into surveillance system , and an novel reasoning subsystem to utilize ICSO knowledge to support information content security surveillance in interpreting surveillance data and improving surveillance decision making. The ICSO is not only a knowledge base but also a SNA (social network analysis) model, thus we could easily implement relative SNA methods to focuses on individualpsilas computer mediated communication (CMC) networks to effectively spot harmful characters. And we test our system on Enron Email Dataset and web pages, the result shows this framework is an efficient and effective solution in information content security and can be spread to other knowledge-based systems.

As digital resources increasingly growing and the economic benefit of digital intellectual property rights being increasingly important, people has been increasingly emphasis on information security issues brought by the data remnants in storage devices. They try their best to prevent the potential risks. In this paper, we survey comprehensively related technologies, standards and trends of erasure, discuss the shortcomings of techniques on adding secure deletion to file systems and on cryptographic to prevent deleted data from being accessible. We focus on secure deletion mechanism in the NTFS file system, combining the asynchronous I/O multi-threading technology. Finally we present a novel data erasing algorithm, Quick Erase, which not only greatly exceeds the speed of the existing international data erasing algorithms but also can be easily combined with a variety of standard algorithms to form various high-speed mixed erase algorithms. It can be used to erase file data and metadata to ensure the security and reliability of data erasing. The test result of Quick Erase indicates that the erasure speed of one big file has reached 10-12 s/100 MB, faster than that of existing secure deletion tools (60-80 s/100 MB). The algorithm has good application prospects for practical applications.

In this paper, we represent a novel approach for detecting multi-relations among network community related activities. By using semantic information and social network analysis (SNA). We can mining various features of groups of people through their network text inter-communications, such as E-mail or BBS and the like. Our method also differentiates and labels distinct relations between people from different aspects of their works, which may help security or management officers to be objective through analyzing the framework of the semantic communities distribution, to extract the clues they need to support the early preventions or controls. The dataset used to validate this study is a collection of Email data from one of Chinese research unit, and the E-mail records from Enron corp., which is retrieved freely from the Internet. This method could be applied to many similar researches for some given purposes.

Nowadays, the task of security monitoring for vast Internet content has the problem of time efficiency. In improving the efficiency, we have studied and compared several typical Multi-pattern searching algorithms such as AC and Wu-Manber algorithms both in English and Chinese environment. Testing results show that the classic Multi-pattern matching algorithms are less efficient in the Chinese environment than in English. And we analyze the factors that cause this: Chinese characters are much bigger a set than English 26 letters, which repeat much but Chinese dose not in a text, and Chinese key word is much shorter than English. According to these factors, this paper presents a novel fast multi-pattern matching algorithm, Byte-Coding algorithm (BC) and a fast semantic content filtering algorithm based on the simple semantic characteristics. By adding the weights of different sizes to the key words, we can improve the accuracy and the speed of filtering system. We thoroughly compare our algorithm with the conventional ones in the speed of filtering. The results show that in multi-pattern mode its speed is at least ten times faster than the traditional AC, WM algorithm and more scaleable with the number of patterns increasing; in simple semantic with frequency calculations mode, this algorithm is still suitable and much faster. The algorithm can also apply to multi-languages environment and rapid parallel or distributed monitoring system as a core module.

A conventional video file contains a single temporally-ordered sequence of video frames. Clients requesting on-demand streaming of such a file receive (all or intervals of) the same content. For popular tiles that receive many requests during a file playback time, scalable streaming protocols based on multicast or broadcast have been devised. Such protocols require server and network bandwidth that grow much slower than linearly with the file request rate. This paper considers "nonlinear" video content in which there are parallel sequences of frames. Clients dynamically select which branch of the video they wish to follow, sufficiently ahead of each branch point so as to allow the video to he delivered without jitter. An example might be "choose-your-own-ending" movies. With traditional scalable delivery architectures such as movie theaters or TV broadcasting, such personalization of the delivered video content is very difficult or impossible. It becomes feasible, in principle at least, when the video is streamed to individual clients over a network. This paper analyzes the minimal server bandwidth requirements, and proposes and evaluates practical scalable delivery protocols, for on-demand streaming of nonlinear media

In an e-commerce system, the database server performance is crucial. A dynamic cache is often used to reduce the load on the database server, which reduces the need for scalability. A good understanding of the workload characteristics of the database server in an e-commerce environment is important to the design, tuning, and capacity planning of the database server. We characterize the database server workloads in a benchmark e-commerce system. We focus on the response time, CPU utilization, the database page reference characteristics, and disk I/Os of the database server. We find that using a dynamic cache can substantially reduce the CPU utilization but not always the number of disk I/Os of the database server. In most cases, using a dynamic cache reduces the temporal locality in database page references, but to a smaller degree than that reported in file servers and Web proxies. Interestingly, in certain e-commerce workloads, using a dynamic cache results in better temporal locality.

Previously proposed streaming protocols using broadcast or multicast are able to deliver multimedia files on-demand with required server bandwidth that grows much slower than linearly with request rate, or with the inverse of client start-up delay. The same efficiencies can be achieved for network bandwidth if delivery is over a true broadcast channel. This paper considers the required network bandwidth for on-demand streaming over multicast delivery trees. We consider both simple canonical delivery trees, and more complex cases in which delivery trees are constructed using both existing and new algorithms for randomly generated network topologies and client site locations. Results in this paper quantify the potential savings from use of multicast trees that are configured to minimize network bandwidth rather than the latency to the content server. Further, we determine the network bandwidth usage of particular immediate service and periodic broadcast on-demand streaming protocols. The periodic broadcast protocol is able to simultaneously achieve close to the minimum possible network and server bandwidth usage.

The Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) has made great efforts in the developments of high power microwave technologies for the purposes of plasma current driving and plasma heating, and also in the developments of millimeter-wave techniques for plasma diagnostics. In 1994, the HT-7 superconducting tokamak that is used for experiments of magnetically controlled high temperature plasmas was constructed in ASIPP. After the establishment of the machine, we have developed a megawatt grade of a microwave system for driving of the plasma current and a megawatt grade of a radio frequency (RF) wave system for the heating of plasma ions. We are just developing a 200 kW-level of millimeter wave system for the heating of plasma electrons. For the diagnostics of plasma properties, we have developed two millimeter-wave systems to detect the radiated millimeter-wave from the magnetically controlled plasmas and a multi-channel far-infrared interferometer system for the measurement of the plasma electron density profile.