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Considering the complexity of wireless sensor network (WSN) coverage problems, which include many variables and a large continuous search space, a WSN coverage optimization method based on an improved artificial bee colony (ABC) algorithm with teaching strategy is proposed in this paper. ABC, which is good at exploration but poor at exploitation, is improved by introducing a teaching strategy in teaching-learning-based optimization (TLBO) that has a rapid convergence but is easily trapped in a local optima. Thus, the proposed algorithm combines the advantages of ABC strong global search ability and TLBO rapid convergence. In addition, to retain the diversity and eliminate the parameter limit in ABC, a dynamic search update strategy is introduced instead of the scout bee phase of ABC. In addition to preliminary examinations with a number of benchmark functions, the performance of the algorithm is verified by solving a complicated wireless sensor network coverage problem. The simulation results verify that the proposed algorithm achieves better balance between global and local search compared with other state-of-the-art algorithms.

Two or more wireless sensor networks coexist in the same space while low energy consuming devices mobiles in a secondary network harvest ambient RF energy from transmissions by nearby active transmitters in the primary network. The channels are allocated to the primary network, while the overlaid secondary network can access the idle channel allocated to perform data transmission opportunistically and operate properly. In this paper, with the jammer implanted, we propose a novel solution in which we execute a deception strategy to exhaust the energy of the jammers. As a result, the energy constraint jammers will be challenging to achieve jamming attacks when the secondary transmitters (STs) transmit information. We formulate the problem first to tackle the issue; that is, we regard throughput optimization issues for ST under jamming attacks as a Markov decision process (MDP). Then, since the focus is mainly on the throughput of the secondary network, a learning algorithm is adopted to maximize it. Through the learning process, the STs can adapt to the dynamics of the primary network while executing proper actions to benefit the overall throughput online. Simulations validate the efficiency and the convergence of the algorithm we proposed.

This paper outlines a new procedure for computer modeling and optimum design for the dynamic mechanical and electrical study of a high-speed backplane connector, which is a key electrical interconnection technology in large communications equipment, ultra-high performance servers, supercomputers, industrial computers, high-end storage devices, and so on. The optimum structure design of contact pairs is important for a backplane connector in meeting multiple challenges in terms of minimizing the maximum insertion force and the contact resistance. Current optimization schemes, such as the quadrature method, are relatively complex. Therefore, we designed the connector contact pairs for simultaneously obtaining the proper insertion force and the contact resistance through a multi-objective particle swarm optimization (MCDPSO) method with simpler settings and faster convergence speed. In this paper, the required insertion force was minimized during the entire process, and the minimum contact resistance was maintained after insertion. To this end, an MCDPSO algorithm was proposed for the connector design. A dynamic weight coefficient was developed to calculate the interval values of the reserved solutions for the selection of the operator, and an external archive update based on roulette wheel selection and gbest selection strategies was developed to increase the diversity of the solutions. A set of optimal structure solutions of the contact pairs was obtained for the subsequent design optimization. The feasibility and effectiveness of the proposed method were verified by comparing with the results from ANSYS finite element simulation.

This paper studies how to deploy relay nodes into traditional wireless sensor networks with constraint aiming to simultaneously optimize two important factors; average energy consumption and average network reliability. We consider tackling this multi-objective (MO) optimization problem with three metaheuristics, which employ greatly different evolutional strategies, and aim at an in-depth analysis of different performances of these metaheuristics to our problem. For this purpose, a statistical procedure is employed to analyse the results for confidence, in consideration of two MO quality metrics; hypervolume and coverage of two sets. After comprehensive analysis of the results, it is concluded that NSGA-II provides the best performance.

With the increasing demand to miniaturize electrical connectors and maintaining its high reliability, micro-rectangular electrical connectors are now widely used. Fretting is generally recognized as an essential failure mechanism for an electrical contact. Considerable work has been carried out to understand fretting of connectors and contact metals, by experiments and simulation methods based on a simplified “hemispheric-flat” model. It is difficult to simulate the contact interfaces between a twist pin and a socket for a micro-rectangular electrical connector. Hence, we develop a 3-D finite contact model. In the present investigation, before the fretting process caused by vibration, an additional insertion step was conducted, in order to obtain the initial state of the contact pair at mated contact surfaces when fretting occurs. We validate consistent behavior for the strand component of the twist pin during the insertion and fretting processes in the simulation. A slight stress release was observed during insertion when the bumped part of twist pin was completely inserted into the socket. The performance of the twist pin, including displacement, contact force, contact area and stress state, during the fretting process was periodically changing due to the vibration of the socket.

The artificial bee colony (ABC) algorithm is a relatively new optimization technique for simulating the honey bee swarms foraging behavior. Due to its simplicity and effectiveness, it has attracted much attention in recent years. However, ABC search equation is good at global search but poor at local search. Some different search equations are developed to tackle this problem, while there is no particular algorithm to substantially attain the best solution for all optimization problems. Therefore, we proposed an improved ABC with a new search equation, which incorporates the global search factor based on the optimization problem dimension and the local search factor based on the factor library (FL). Furthermore, aimed at preventing the algorithm from falling into local optima, dynamic search balance strategy is proposed and applied to replace the scout bee procedure in ABC. Thus, a hybrid, fast, and enhanced algorithm, HFEABC, is presented. In order to verify its effectiveness, some comprehensive tests among HFEABC and ABC and its variants are conducted on 21 basic benchmark functions and 20 complicated functions from CEC 2017. The experimental results show HFEABC offers better compatibility for different problems than ABC and some of its variants. The HFEABC performance is very competitive.

Ultrasonic sparse array can increase the resolution by enlarging the aperture without adding system complexity, and it has characteristics of large scanning range and high detection accuracy, which is one of the most promising applications of ultrasonic nondestructive testing technology. The application of reciprocity theory to scattering of guided waves by flaws was studied. A finite element model of sparse array ultrasonic testing was established, to investigate the scattering field distribution characteristics and the interaction of different typical defects, using the finite element model, analyzes the influence of scattering characteristics of defects for sparse array ultrasonic imaging detection. Based on tomography imaging, proposed a defect recognition method based on the sparse scattering information extracted from defect scattering coefficient matrix, and analyzed the relation between sparse scatting coefficient matrix and full scattering coefficient matrix. Based on the principle of ultrasonic guided wave tomography, a sparse array ultrasonic guided wave imaging technique has been realized. The results show that the method successfully detects and displays defects correctly. Ultrasonic guided wave imaging techniques can potentially be useful in detecting defects in plate-like structures.

Two different hybrid processes which contain the laser–tungsten inert gas (TIG) double-side welding (LTDSW) and the laser–TIG single-side welding (LTSSW) were applied on 5A06 aluminium alloy sheets. The three-dimensional (3D) finite element models are developed to investigate the thermally induced stress field during the hybrid welding. Based on the thermal history data obtained from these combined heat source models, the residual stress distribution in weld metal, heat affected zone and base metal characteristics have been calculated and found to be in reasonable agreement with the X-ray diffraction (XRD) experimentally measured values. The results show that the longitudinal residual stress in the LTDSW welded joints is less (10–12 %) than that of the LTSSW welded joints. Meanwhile, from the mechanical and metallurgical point of view, it could be confirmed that it makes a good sense to use LTDSW instead of LTSSW for the 5A06 aluminium alloy welding structure.

The laser soldering process was introduced in Micro-USB electronic packaging in this paper. Numerical modeling and analysis was used for laser process parameter design, because experimental measurements of peak temperature and soldering stress are expensive and often intractable. Accurate knowledge of the residual stress and distortion is a prerequisite for the reliability of the electric connector. The present work proposes a three-dimensional transient heat transfer model of Micro-USB package laser soldering process. The calculated thermal cycles and distribution are subsequently used to calculate the distortion and thermal stresses. Meanwhile, the effect of process parameters on residual stress and pin distortion was discussed, and the tensile strength, microstructure, and residual stresses of laser soldering were tested. It can be concluded that the proper laser soldering parameters and power can improve the mechanical property of solder joints on Micro-USB connector. Copyright © 2014 John Wiley & Sons, Ltd.

The rolling element bearing is one of the most extensively used components in various rotating machinery, and it is therefore critical to develop a suitable online rolling element bearing fault-diagnostic framework to improve a rolling element bearing system’s failure protection during conditional operations. In this paper, a hybrid fault-feature extraction method by detecting localized defects and analyzing vibration signals of rolling element bearings via customized multi-wavelet packet transform is proposed, in which the swarm fish algorithm has been utilized for the minimization of signal residual to determine the adaptive prediction operator. With good properties of concurrent symmetry, orthogonality, short support and high-order vanishing moment, the multiple wavelet functions and scaling functions are defined for the hybrid fault-feature extraction, which match the diverse characteristics of hybrid fault and extract coupling features, and the proposed lifting scheme-based multi-wavelet packet transform is highly effective. Then, the proposed method is validated by rolling element bearing experimental results, which show that this approach can effectively extract the hybrid fault features of inner race and rolling element.

We introduce an internet based crossover robot remote control competition project that is an international cooperative program based in Japan, China, Thailand, and Taiwan. This competition is an important component of a long-term higher education reform project aiming to develop a practice based innovative educational methodology jointly promoted by the Ministry of Education, Culture, Sports, Science & Technology of Japan and the University of Electro-Communications. The competition project includes two subjects: the competition itself and the communication and cooperation between students in two countries. The basic mode of the competition is a locally controlled robot and a remotely controlled robot cooperate with each other to complete some tasks. As a unique feature of the project, the student–student communication and cooperation are increased through a specially designed team organization structure that each team consists of two groups from different universities in different countries and the team members are required to cooperate through the internet to complete the competition. The competition has been successfully held four times and the results show it greatly benefits the students, and is expected to promote the development of the practice based educational methodology in the near future.

A kind of ultrasonic motor, whose rotor is driven by stator’s inner circumferential surface, has been designed and fabricated. The paper has analyzed the stator deformation characteristics under bending mode by using finite element method, identified the motor’s working mechanism with two-phase voltage drive, and studied the different functions of tangential and radial displacements of the stator’s inner circumference small teeth under bending mode and pointed that the above mentioned displacements along two directions of small teeth could drive the rotor continuously with single-phase voltage. The paper has discussed the motor’s rotary direction reversing and put forward a concrete scheme of reversing with single-phase voltage drive. The mode of the stator was obtained by experiment. Under two-phase and single-phase voltages, running experiments of the motor have been accomplished and the corresponding characteristics curves have been drawn. Taken above analysis result as driving mechanism, a kind of thin-type standing ultrasonic motor can be developed further.

Discontinuous welding is the most common welding type used in the fabrication of structural members in shipbuilding, automobile and other industries. Fillet-welded joints usually suffer from various welding deformation patterns, such as longitudinal shrinkage, transverse shrinkage, angular distortion and longitudinal bending. Welding deformation has negative effects on fabrication accuracy, external appearance and various strengths of the welded structures. This study describes the thermal elasto-plastic analysis using finite element techniques to analyze the thermo-mechanical behavior and evaluate the residual stresses and distortion of 5A06 aluminum alloy structure in discontinuous welding. Furthermore, this work employs the technique of submodeling and substructure to guarantee the simulation accuracy and improve computational efficiency. Also discussed are the effects of welding sequence and weld length on the residual stresses and distortions. In addition, the generation mechanism of angular distortion is clarified through numerical simulation.

The magnetic flux leakage (MFL) method has established itself as the most widely used inline inspection technique for the evaluation of pipelines. The MFL signal is usually contaminated by various noise sources This paper presents the empirical mode decomposition (EMD) for enhancing signal-to-noise ratio. Experiments are conducted on the pipeline steel samples with different depth artificial defects. The MFL signal is decomposed into several intrinsic mode functions by EMD. Some modes are selected to reconstruct a new signal considering their frequencies and energy. The reconstructed signal has a better signal-to-noise ration. The results show that EMD technology is efficient in eliminating noise in the MFL signal.

Micro-D electrical connectors are extremely crucial, highly reliable industrial devices in the fields of aerospace, military, and medicine. The geometry and size of the twisted wire contacts of micro-D electrical connector are vital for its mechanical properties and structural stability. In this investigation, dynamics modeling, numerical simulation and experimental tests of the insertion-extraction processes were applied on the twisted wire contacts of micro-D electrical connector. The computer aided design and engineering (CAD-CAE) parameterized models of the twisted-wire contacts were developed, and the theoretical models were also built on the basis of the mechanics of the materials. Nonlinear dynamics simulation was performed by ANSYS/LS-DYNA finite element software to analyze the force and stress distribution of the insertion-extraction processes. The results showed that the insertion force (~0.34 N) was higher than the extraction force (~0.32 N), and the stress concentration occurred on the clamping end and the convex hull of the pin. The mechanical model and numerical simulation were then verified by the experimental tests. By the orthogonal test and the sequential quadratic programming optimization method, the insertion-extraction forces could be reduced to obtain the optimal contacts structural parameters. This theoretical study will help researchers in the design, manufacture, and employment of micro-D electrical connectors.

A non-contact optical-electric measuring principle is introduced that is based on pulsed laser light source and high-precision CCD imaging technology. The diameter- measuring device design framework and some basic structure units are given. Meanwhile, the FPGA (Field Programmable Gate Array)-based devices of the linear array CCD data acquisition and signal-processing system including various functional modules are discussed emphatically.

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is a devastating disease of rice worldwide. Among the 85 mapped resistance (R) genes against blast, 13 have been cloned and characterized. However, how these genes originated and how they evolved in the Oryza genus remains unclear. We previously cloned the rice blast R-genes Pi2, Pi9, and Piz-t, and analyzed their genomic structure and evolution in cultivated rice. In this study, we determined the genomic sequences of the Pi2/9 locus in four wild Oryza species representing three genomes (AA, BB and CC). The number of Pi2/9 family members in the four wild species ranges from two copies to 12 copies. Although these genes are conserved in structure and categorized into the same subfamily, sequence duplications and subsequent inversions or uneven crossing overs were observed, suggesting that the locus in different wild species has undergone dynamic changes. Positive selection was found in the leucine-rich repeat region of most members, especially in the largest clade where Pi9 is included. We also provide evidence that the Pi9 gene is more related to its homologues in the recurrent line and other rice cultivars than to those in its alleged donor species O. minuta, indicating a possible origin of the Pi9 gene from O. sativa. Comparative sequence analysis between the four wild Oryza species and the previously established reference sequences in cultivated rice species at the Pi2/9 locus has provided extensive and unique information on the genomic structure and evolution of a complex R-gene cluster in the Oryza genus.

Inspection of welding precision is important to ensure the quality of High Voltage Ceramic Capacitor (HVCC). The purpose of this paper is to propose an automatic inspection method which is used to check the parallelism and position after welding. The method is, firstly, capture images with the help of a CCD camera. Next, detect edge with Canny operator. Thirdly, use modified Hough transform to find circles for parallelism checking. Fourthly, execute the parallelism inspection in the way of comparing distance. Fifthly, use the least square method to ascertain circles for position checking. Last, execute position inspection in the way of intersecting circles. In experiments of three different sizes HVCC, the proposed method is proved to be very effective.

The collaboration modeling and simulation with software interfaces based on high level architecture (HLA) is presented. According to the data exchange standard in CAD domain, research the sharing of simulation model, simulation model reuse and simulation model transformation on the collaboration simulation platform. After analyzing the function of the mechatronic systems, the logical structure of a mechatronic simulation system based on HLA was given. The relevant key technologies were also detailed. Through a secondary development of commercial simulation software interfaces, HLA federation was developed with the support of object-oriented approach. Different function of software interfaces were developed as different federates. In the system simulation practice of electronics manufacture equipment (The automatic assembly machine of surface mount high voltage ceramic capacitors) virtual prototype, connecting 3D entity model, dynamic model and finite model with control model through simulation federation by system platform, the multi-disciplinary integrated model of the assembly machine multi-body dynamics and system control collaborating was established.

In order to realize the test visualization process, we have done research and development on gas turbine engine test visualizations. In this paper, a set of aircraft engine test visible plan is introduced, which has used the object-oriented thought to build basic module, and the three dimensional (3D) module of gas turbine engine and two dimensional (2D) graph of dynamic data tested has been applied fully, which show the data coming from the data processing module. And the gas turbine engine model classes and data processing computation class were programmed with VC++ language. The relations have been given between software module structures and the software processing flow have been expressed. Finally, we have reached the effect of high quality and speed by integrating some popular numerical analysis and cartography Software. The system shows that the gas turbine engine test visualizations is effective in making the gas turbine engine test data visualizing and is helpful to understand the performance of tested object to the engine designer.

How general the ATS (automatic test system) is influences the application range and the maintenance cost of test systems directly. However, it is the reuse of software that will make the ATS more general. Herein this paper adopts a method of developing software based on software bus; a reconfigurable model of automatic test system is researched and designed. And the interchangeable instrument technology is combined in this paper to realize the reconfiguration of the test functions and the architecture of ATS. Thus the extent of reusing test software will be toned up, which will also enhance the general-purpose of ATS.

In view of the underground moving target localization question, a solution has been proposed which is based on the integration of RFID and GIS. This paper presents relevant concepts of the RFID and GIS; analyzes the working principle, RFID reader positioning error and its installation methods as well, which are on the basis of the RFID and GIS moving target positioning system. In the paper, each of the moving targets carries an RFID tag which has the property information of the moving target. The distances from every RFID readers to their laneway entry have been stored in the database in order that the underground reader calculates and locates the position of moving target. Therefore, the system can realize the localization and track on underground moving targets, and thus can increase aid effectiveness by locating the affected staffs quickly and accurately. Moreover, the system is convenient for maintenance and ease to manage.

With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage (MFL) method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. This paper presents the typical three dimensional (3D) defects were accurately modeled and detail MFL signal in test surface were calculated by 3D finite element method (FEM). At the same time, the experimental investigation on defect inspect in steel pipeline using MFL were carried. The results show that the 3D FEM is an effective analysis method for steel pipeline MFL inspect.

Networked control systems are one type of distributed real-time control systems where sensors, actuator and controllers are interconnected by communication networks. The insertion of the communication network makes the analysis and design of a networked control system complex. So the performance of the control loops not only depends on the design of the control algorithms, but also on the scheduling of the shared network resource. A co-design method based on the integrated Earliest Deadline First (EDF) scheduling algorithm and the Integral of the Absolute Error (IAE) is proposed in order that the communication medium is more efficiently used and control performance is improved. The presented method can adjust the sampling period, handle three types of message and guarantees real-time transmission of periodic and aperiodic message, and non-real time message. The simulation results show that the proposed co-design method is available and improve the system resources efficiency.

An efficient approach is proposed to develop the efficient expert system for intelligent instrument fault diagnosis. According to the characteristics of intelligent instrument faults, the hybrid inference method combined with the rule-based reasoning and the case-based reasoning is adopted. In the rule-based reasoning, a hierarchical search method is proposed, and the diagnostic priority of each rule in a specified search level is determined based on a fuzzy multi-attribute group decision making method. According to such an inference strategy, the knowledge base in this expert system is optimally designed in SQL server database technology, and an efficient expert system for intelligent instrument fault diagnosis is developed in VS.Net. In actual use, the expert system shows higher diagnosis efficiency than its first version.

With the rapid developments of Internet technologies, remote access and control via Internet is becoming a reality. A realization of the web-based laboratory (the W-LAB) was presented. The main target of the W-LAB was to allow users to easily access and conduct experiments via the Internet. While realizing the remote communication, a system, which adopted the double client-server architecture, was introduced. It ensures the system better security and higher functionality. The experimental environment implemented in the W-Lab was integrated by both virtual lab and remote lab. The embedded technology in the W-LAB system as an economical and efficient way to build the distributed infrastructural network was introduced. Furthermore, by introducing the user authentication mechanism in the system, it effectively secures the remote communication.

The commonly used and cost effective corrosion inspection tools for the evaluation of pipelines utilize the magnetic flux leakage (MFL) technique. The MFL signal is usually contaminated by various noise sources. In this paper, we propose that the pipeline flaw MFL signal is extracted using the ensemble empirical mode decomposition (EEMD) and the sparsity. At first, we introduce the EEMD method. The EEMD defines the true intrinsic mode function (IMF) components as the mean of an ensemble of trials, each consisting of the signal plus a white noise of finite amplitude. Moreover, sparsity selection restriction was defined. Then, The MFL signal is decomposed into several IMFs used for signal reconstruction. Some modes are selected to reconstruct a new signal considering their sparsity. Finally, the comparison is made with the empirical mode decomposition. At the same time, the comparison of the selection restriction between the sparsity and the energy is described. The results show that the EEMD and the sparsity is an efficient technology with the pipeline flaw extraction.