Earticle

Nodes of wireless sensor network (WSN) will appear various faults, because the influence of many unavoidable factors and environment is very complex and harsh. Rough set can deal with incomplete information, especially in the data reduction, and it is easy to realize low energy consumption problem of on-line fault diagnosis based on WSN node energy Co. This paper adopts attribute reduction algorithm by integrate rough set with neural network model to eliminate WSN node failure, so as to achieve data reduction and to improve the accuracy and efficiency of fault diagnosis purpose. The paper makes use of rough set and neural network to the failure phenomenon of WSN node by using knowledge reduction of discernibility matrix and logic operation, eliminating the redundant attribute WSN node fault. Then, fault decision complex table is built by he classified fault, and finally determine the fault location corresponding to fault phenomenon and repair of the final decision table. The experimental results show that this method improves the robustness of the fault diagnosis, and enhances the practicability of WSN limited energy.

Transport layer protocol is used by the majority of the applications in wire and wireless networks. In addition, there are a lot of challenges in testing and applying this protocol in highly dynamic topological Vehicular Ad Hoc Networks (VANET). Quality of Service and reliability of the Transmission Control Protocol in vehicular wireless network is not assured due to frequent link failure, short duration of session, packet drop due to congestion, multipath propagation delay etc. Performances of the Transmission Control Protocol (TCP) are highly depended on congestion control algorithms that limit the amount of data to be transmitted based on the estimated network capacity and receiver’s TCP window. Goal of this paper is to analyze and evaluate TCP congestion control algorithms in VANET environment and suggest the most appropriate of them. Throughput and packet delivery ratio is examined changing the C2C-CA message intervals in order to find out the best solution for VANET environment. Important conclusions are obtained that could be of great use for professionals that work in this area.

For traditional RSS location method has higher requirements of environmental factors, the workload in the design and calibration and operation phase is great and efficiency is lower, so it put forward a kind of wireless sensor network localization algorithm based on online calibration modeling of RSS anchor node. First of all, to filter the anchor nodes with weak signal and large uncertainty by using the standard deviation threshold method, and make on-line modeling on the relationship between the distance of anchor node and the unknown node and received signal strength. Secondly, using the cycle calibration way for real-time correction of the on-line model, then locate the unknown node by using the weighted average method, thus establish adaptive mechanism of the environmental factors to realize the real-time accurate positioning of the node. Finally, through simulation to indicate this method can effectively locate the unknown nodes in wireless sensor network and its precision meets the requirements, algorithm is simple and easy to implement with practical application value.

In allusion to issues that partitioning algorithm of traditional social network community is generally lacking in comprehensive consideration of node and link attributes as well as full expression of model and mechanism using attributes of node and link. This paper presents a social network community partitioning algorithm fusing node and link attributes. The algorithm has blended similarity of node properties, link weights between nodes and link attribute information, making definition of the similar weights, and on this basis, social networking community division is realized combined with condensation algorithms. Experiments show that the algorithm has remarkable effects on community partition with obvious attributes in social network.

The paper provides a simulation model of IEEE 14 bus system for short circuit studies and analysis of symmetrical fault using MiPower software. At the event of a fault occurrence, short circuit studies are performed to obtain current flow magnitude at different time intervals for a power system until steady state condition is achieved. The paper gives simulation result for the current which flows in different parts of the power system immediately after occurrence of a fault. The data obtained is further used to decide switch gear ratings and circuit breakers and also aids in setting and coordination of protective relays. Further the simulation result provides data regarding the contribution of different power system apparatus to the fault located at different buses in the power system and it gives an efficient, accurate and easy way to analyze symmetrical faults in a given power system.

Against the problem that quantitative localization is concentrated on single-source localization, this paper studies the quantitative multi-source localization methods based on wireless sensor network. Firstly, the log-quantization strategy which reflects the characteristics of acoustic source is proposed. The sensor node transmits the quantized information to base station according to the measurements and log-quantization strategy. Secondly the based station estimates the location of the sources according to the proposed method termed as multiple source localization based on possibilistic C means clustering algorithm. Finally the efficient of the proposed method is verified by the simulation under different parameters. The simulation results show that the proposed method could accurately estimate the location of source. And the proposed method is robust to the packet loss rate.

At present, lack of teaching effectiveness has become a serious problem in college, especially in the public mathematics courses. This paper attempts to study the effectiveness of mathematics classroom teaching through the network survey, as the Internet becomes popular media, Internet survey will become a mainstream form of investigation. The results show that teachers are more inclined to lecture style and question type teaching in mathematics course, while students prefer to explore cooperative learning mode. At the same time, 28% students never participate in course interaction, and 22% students only participate in course interaction which he thinks important. So that, how to mobilize the enthusiasm of the students is the main factor to improve the efficiency of classroom teaching. Generally speaking, effective teaching is comprehensive, dynamic and comprehensive, it should not only let the students get the basic knowledge, but also teach them the corresponding learning methods.

A large number of pilots are utilized to acquire channel information in traditional channel estimation for Orthogonal Frequency Division Multiplexing (OFDM) system, which leads to lower spectrum efficiency. For exploiting the sparse channel characteristics of 3GPP multipath channels, we employ the Compressed Sensing (CS) approach for channel estimation. Two CS-based recovery algorithms, Orthogonal matching pursuit (OMP) algorithm and Compressive sampling matching pursuit (CoSaMP) algorithm, are considered in this paper. The Bit error rate (BER) and Mean squared error (MSE) performance using traditional least square(LS), and two CS-based algorithms are given. Simulation results demonstrate that the CoSaMP algorithm achieves best performance with fewer pilots among three algorithms under 3GPP channels.

When making wood board production, defects on board will influence the machining process automation degree. Therefore, how to fast, accurately remove of wood defects and realize optimal combination cutting stock problem has always been a research hotspot in the field of wood processing. According to the decayed wood board, the paper designed the one dimensional optimization cutting stock combined scheme and mathematical model, adopted the adaptive genetic algorithm imitating the biology evolution to code some optimization scheme initialized by chance, and improved these schemes by selection, crossover and mutation operation. At last these schemes converged to the optimum. The results showed that the adaptive genetic algorithm can achieve a good one dimensional wood board optimization cutting stock problem, through the realization of genetic algorithm in MATLAB, and makes the wood board utilization rate reached 98.9%.

Development of an efficient routing protocol is one of the major key challenges in the design of Mobile ad hoc networks (MANETs). DSR reactive routing protocol is the most preferred routing protocol in MANETs due its capability to store already discovered routes in the node’s cache. In DSR routing protocol, in order to find a route to the destination, the source node broadcasts RREQ (Route Request) packets to its all neighbouring nodes and this broadcasting of RREQ packets results in more overhead. In this paper, we propose a multicasting technique to enhance the performance of DSR routing protocol and to reduce the broadcasting overhead. The performance analysis of DSR and enhanced DSR (EDSR) is carried out by varying number of nodes under different traffic conditions with different packet sizes and different network sizes. Also the performance analysis of DSR and enhanced DSR is carried out under different propagation models. The performance metrics used for the performance analysis of DSR and Enhanced DSR are Packet Delivery Ratio (PDR), Average End-to-End Delay, Throughput, Normalized Routing Load (NRL) and Energy Consumption.

In consideration of the characteristics of visible light communication (VLC) and orthogonal frequency division multiplexing (OFDM) signal modulation mode, this paper presents some improvements from two aspects of timing metric function and training sequence structure on the basis of the traditional algorithms. In order to solve the problem of the correlation peak plateau and achieve the symbol accurate positioning, the power of the improved algorithm is normalized on the principle of maximum sliding auto-correlation (SAC). The simulation results show that the improved algorithm can obtain a more excellent timing synchronization performance and a lower symbol error rate (SER) in both the additive white Gaussian noise (AWGN) channel and the multipath frequency selective fading (MFSF) channel. Especially under the environment of a low signal noise ratio (SNR), the improved algorithm has overwhelming advantages over other three traditional algorithms.

A novel metal-only reflectarray element with double split square ring slot laser cut into a metallic thick stainless steel plate is proposed in this paper. By using this unified slot structure, the dielectric substrate usually used in traditional reflectarray designs can be removed. The proposed technique can provide a more than 400° phase range with relatively smoother slope. In order to verify the phase data, a 25°-beam-steering metal-only reflectarray operating at 12.5 GHz is designed and simulated. A 1-dB gain bandwidth of 12% is achieved, which is slightly wider than that of reflectarray designs consisting of conventional patch elements. The proposed metal-only structure can better withstand the extreme outer space environment and effectively reduce the antenna cost.

The routing protocol transport the best connection, creating during message in the network. The router can work with the help of routing protocols. The various routing protocols can be present, but the most famous routing protocols are Routing Information protocol (RIP) and the Open Shortest Path First (OSPF). Smart Open Shortest Path First (S-OSPF), which offers the extended representations for conventional OSPF gives less congestion ratio by allocating traffic. Multicast Open Shortest Path First (MOSPF), it offers the facility to forward multicast datagram from one network to another. In this paper, we are defining the two protocols and the related worked on them. In this each link provides the autonomous system to create the shortest path to makes and creates the destination tables. Both logical and hardware address play the important roles, responsible for getting packet and forward through a correct destination host.

With the explosive growth of the web information, acquiring the target information quickly, precisely and effectively in a large number of network information is restricted by many factors. In response to it, this paper analyzed the key technician part in the network information search engine-web crawler technology and proposed a network information target search model based on the web vertical crawler system with discussion on the implementation of the corresponding search strategy. Firstly, it builds the structure of the web crawler system and analyzes different function models. Next, it discusses some crucial problems including the options of deleting duplicated URL, the strategies to choose duplicated URL deletion method and the control model of error probability estimate model to acquire the closest network information to the target information. Finally, it verifies and discusses the operability and effectiveness of the model and the implementation strategy through case study.

The estimation error of the least square method in traditional Distance Vector-Hop (DV-Hop) algorithm is too large and the Particle Swarm Optimization (PSO) algorithm is easy to trap into local optimum. In order to overcome the problems, a fusion algorithm of improved particle swarm algorithm and DV-Hop algorithm was presented. Firstly, PSO algorithm was improved from aspects of particle velocity, inertia weight, learning strategy and variation, which enhanced the ability to jump out of local optimum of the algorithm and increased the search speed of the algorithm in later iterative stage. Then, the node localization result was optimized by using the improved PSO algorithm in the third stage of the DV-Hop algorithm. The simulation results show that compared with the traditional DV-Hop algorithm, the improved DV-Hop based on chaotic PSO algorithm and the DV-Hop algorithm based on improved PSO, the proposed algorithm has higher positioning accuracy and better stability, which is suitable for high positioning accuracy and stability requirements scenes.

Optical wireless communication (OWC) system is considered as a promising solution to meet the increasing demands of high data transmission rates and channel bandwidth over a long link distance. The Optical wireless communication system can be used in various applications such as inter-satellite links, inter-aircraft links, terrestrial links etc. In this paper, the performance of an optical wireless communication link with varying number of transmitters and receivers is evaluated. The performance of the system has been analyzed on the basis of BER, Q Factor, SNR, and total power of the received signal. The results show that by using multiple transceiver technologies, the quality of the received signal is enhanced for long distance links operating at high data transmission rates.

Network survey is a new kind of social investigation method, which is developed with the development of network technology, especially in the field of Social Science. In this paper, the author analyzes the performance of body language teaching in physical education by using network data, the result shows that students’ attention, confidence and energy has increased in body language teaching. At the same time, by comparing the control group and the experimental group data, we find that movement proficiency of experience group students has increased more significant. The total score of experience group is 86.10 5.24, while control group is 80.03 6.33. Also, we find that the classroom atmosphere is active in the experimental group, students showed active response, high emotion, thinking more sensitive and focused attention. So that, effective use of Body language teaching will have a positive influence in physical education

As a new branch of location-based query, space keyword query has gained extensive attention from researchers and become a new hotspot of database filed. Able to comprehensively consider the distance between query object and query point as well as similarity degree of keywords, such query can better satisfy specific requirements of location-based services. In this paper, a space keyword index structure is designed, so as to effectively organize keyword information, location information and index information of objects on various sides in road network. Besides, keyword k-nearest neighbor query of road network under wireless broadcast environment is proposed. Finally, performance of the proposed index structure and algorithm is verified through simulation experiment.

In order to explore the Influencing Factors of Switching Intention by Mobile Number Portability .We build up a structural equation model for Chinese mobile customers’ influence factors on MNP intention. Including competitive attraction, subjective norm, and policy perception, customer satisfaction, switching barriers, network quality, awareness rates, perceived service quality, usage habits and switching cost. According to empirical analysis, we find that customers with different perceive levels in MNP polices have significant differences in switching intention. And through the analysis and comparison, we find that the influence factors and the path coefficients of the customers’ switching intention are also different when they have different perceive levels in MNP policy.

A statistical analysis has been made on 969 two-syllabic words in Uyghur Acoustical Database. The major part of this paper concentrates on the basic acoustic features of two-syllabic harmonious words including formant frequency, resonance peak value, vowel duration, vowel pitch and the sound intensity. And we have summarized certain rules and conclusions of great importance for adjusting vowel harmony in parametric speech synthesis or waveform concatenated speech synthesis system.

Coded structured light measurement is the important method of modern non-contact optical measurement, restricted by the camera field of view, the surfaces to be measured can complete a single perspective measurement, this is the 3 d point cloud registration, point cloud registration can reflect three-dimensional topography on the surface of the object, and it has reached the requirement of comprehensiveness.This paper has built coded structured light 3 d measurement system, to explore 3 d point cloud registration method based on regular hexahedron color targets with high accuracy, fast registration, which can be applied to industrial components comprehensive measuring characteristics.

A compact planar monopole antenna with standard band-notched characteristic suitable for ultra wideband (UWB) applications is presented. This microstrip-fed antenna, consisting of an inverted U-shaped slot on the radiating patch with defected ground structure. The designed antenna has a small size of 12×18×1.6 mm3 and operates over the frequency band between 3.7 and 10.4 GHz for VSWR < 2, while showing the band rejection performance in the frequency band of 5.1 to 5.9 GHz (WLAN) and is suitable for applications of communication systems, wireless communications, various kinds of antenna test ranges, and high resolution microwave imaging systems. The proposed UWB antenna is simulated by using the CST Microwave studio.

For the connection problems of VANETs, the paper analyzes the link connection model. Existing studies on multi-hop connection assume that the link is independent and identically distributed and did not consider the non-independence between continuous links. For this purpose, this paper presents a multi-hop connection probability model based on non independent links. By the relative distance between vehicles, combined with the vehicle movement model, the vehicle distribution is derived and the probability of multi-hop connection is deduced. The simulation data show that the connection probability varies with the relative distance of the vehicles and the probability of the connection decreases with the increase of relative distance, consistent with the results of the theoretical derivation.

In-network caching is an important feature of Information Centric Networking (ICN). All routers in ICN will maintain caching ability, and, for each request, contents are cached at routers along the delivery path. This kind of on-path caching can reduce overall retrieval time. However, the same contents may end up to be cached all over the network causing wastes of caching space and decrease content diversity. Coordinated caching policy decides which contents to be stored at which routers cooperatively for better utilizing cache space. Nevertheless, with limited storage, most of coordinated caching policies use all the caching capacity to store popular contents. It may raise a fairness issue in which unpopular contents can not access caching space and thus lower overall performance. In this paper we propose a hybrid coordinated caching algorithm. By splitting cache space into two parts running different mechanisms respectively, it provides accessibility for both popular and unpopular contents. The evaluation results show that fairness is uplifted while maintaining high hit ratio and minimized latency.

With the growth of increasingly complex in wireless ad-hoc networks, performance modeling and evaluation play a crucial part in their design process to ensure successful deployment and exploitation in practice. Compared with the actual implementation (testbeds), simulation has become a valuable tool, which allows studying large scale systems that cannot be built practically. However, most simulators currently used for such networks are intended to evaluate individual routing protocol, which should be extracted from the source code and rewritten in accordance with the simulator’s requirements. Thus, in this paper, we design a new wireless ad-hoc network simulator, called Time Step-based Wireless Ad-hoc Network Simulator (TimSim). It is intended to facilitate the migration of simulation code to real devices via providing useful APIs with real device driver. We use a discrete event processor with time step-based feature as the simulating engine, and the data can be transmitted in bit-level. A unique feature of TimSim is its ability to support the simulation of multi-thread programming. Additionally, we import database access to store the simulation information. Extensive experiments have been conducted to evaluate the efficiency of TimSim. Furthermore, a case study on a real system has been presented to illustrate its practicability.

Frequency-hopping communication has the capability to resist narrowband interference, which is in direct proportion to the hopping rate. In frequency-hopping system, interference signals exist in partial de-hopping frequency-hopping signals, equivalent to time-varying interference signals existed in the frequency-hopping signals. Through integrating the diversity combining techniques of fast frequency-hopping communication with singular value decomposition method, this paper detects the frequency-hopping points, masks them, and then combines with undisturbed frequency-hopping signals. MATLAB simulation shows that narrowband interference is well restrained and the system BER is obviously improved.