Multi Directions Research Articles

Segmented disc dynamo with symmetric multidirectional patterns of multiscroll chaotic attractors

Rather than adopting the common approach that the multiscroll attractors are obtained through reconstruction of nonlinear functions, this work presents a systematic mechanism for designing multidirectional symmetric multiscroll patterns of chaotic attractors. The present scheme is based on the multilevel signal that work with the nonlinearities and state variables of chaotic system to generate symmetric multidirectional patterns of multiscroll chaotic attractors (MPMCA). To illustrate the mechanism of this systematic approach, the coefficients of quadratic terms of segmented disc dynamo are modified and designed a chaotic system that generates a chaotic attractor consisting of two pairs of symmetrical attractors. The state variables under the multilevel signal are transformed and then combined the symmetric attractors to generate a complete family of symmetric MPMCA in multi directions (including one directional (1D), two directional (2D) and three directional (3D) symmetric patterns of multiscroll chaotic attractors). Chaotic dynamical characteristics of symmetric MPMCA are analysed​ by means of equilibrium points distribution and phase portraits. Matlab simulations results obtained in this work are consistent well with our theoretical analysis verifying the effectiveness of the presented scheme.

A mosquito-inspired self-adaptive energy harvester for multi-directional vibrations

In this paper, a new concept of direction self-adaptive energy harvesting is put forward for multi-directional vibrations, and a novel direction self-adaptive piezoelectric energy harvester (DSPEH) is explored by introducing a self-adaptive rotation mechanism into the cantilever beam inspired by mosquito wings to validate the new concept. Different from the conventional piezoelectric energy harvester (PEH), the proposed DSPEH has an additional rotation degree of freedom obtained by the rotation unit to realize self-adaptive rotation passively without any manual intervention or power supply. Working principle and theoretical analysis of the proposed DSPEH are conducted and a prototype is fabricated to demonstrate the concept. The energy harvesting performance of the proposed DSPEH is investigated under sweeping frequency and harmonic excitation, and the key parameters affecting the energy harvesting efficiency, such as damping parameters and mass eccentricity coefficient, are analyzed in detail. Simulation and experimental results are in good agreement. Owning to the characteristic of self-adaptive rotation, the most attractive feature of the proposed DSPEH is not simply the ability to realize multi-directional vibration energy harvesting, but the capability of achieving stable and high voltage output levels in multi directions, which is fundamentally distinct from the conventional PEH and other multi-directional energy harvesters. The average output voltage is 30% higher than that of the conventional PEH. Compared with other multi-directional energy harvesters, the proposed DSPEH also has higher energy harvesting efficiency.

Texture Image Analysis Based on Joint of Multi Directions GLCM and Local Ternary Patterns

Texture Image Analysis Based on Joint of Multi Directions GLCM and Local Ternary Patterns

A Prototype Model Design of Wide Band Standard Reference Rod-Dipole antenna for 3-Axis EMC Measurement with hybrid Balun for 0.9 to 3.2GHz

Every electronics equipment must deal with EMC test. The testing laboratory of electronics equipment for radiation emission must have accurate calibrated antennas. The field strength of total radiated radio frequency is average of all incident signals at given point, this incident spinals originates from various directions. In order to measure three components of all electric field vectors, a tripole antenna is most beneficial over conventional antenna because of it responds to signal coming from multi directions. This paper presents novel three axis wide band calculable rod-dipole antenna with hybrid balun for the range of 900MHz to 3.2GHz frequencies, the proposed antenna is small in size and good electrical characteristics, the Important parameters measured and verified with designed values. Return loss S11 more than -10dB within the frequency range 900MHz to 3.2GHz. The result of this articles are evident that, efficient construction of antenna with low cost, light weight module applicable for EMC pre-compliance test at open field site.

Data Reduction of Point Data by using Rendering Images from Multi Directions

Data Reduction of Point Data by using Rendering Images from Multi Directions

Multi-focus Image Fusion Algorithm Based on Motivated Pulse Coupled Neural Networks Using Nonsubsampled Contourlet Transform

In this paper, a multi-focus image fusion algorithm based on motivated pulse coupled neural networks using nonsubsampled contourlet transform (NSCT) is proposed. Firstly, NSCT is used to decompose the source image in multi scale and multi directions to obtain the low frequency coefficients and high frequency coefficients. Secondly, Fourier transform method is used for saliency detection. We choose the coefficients which have larger saliency for high frequency coefficients. In the process of choosing the low frequency, the spatial frequency is used as the input of the Pulse coupled neural network (PCNN) to obtain the firing times of the low frequency. If the firing times of two images are not the same, then we choose coefficients which have larger firing times. Otherwise, coefficients which have larger saliency will be chosen. Lastly, inverse transformation of NSCT is used to obtain the fused image. The proposed method is compared with four other common methods, and the experimental results show that the proposed method performs better on both subjective and objective evaluation indicators.

Bifunctional acoustic metamaterial lens designed with coordinate transformation

We propose a method to design bifunctional acoustic lens using acoustic metamaterials that possess separate functions at different directions. The proposed bifunctional acoustic lens can be implemented in practice with subwavelength unit cells exhibiting effective anisotropic parameters. With this methodology, we experimentally demonstrate an acoustic Luneburg-fisheye lens at operational frequencies from 6300 Hz to 7300 Hz. Additionally, a bifunctional acoustic square lens is proposed with different focal lengths for multi directions. This method paves the way to manipulating acoustic energy flows with functional lenses.

Twinning and detwinning behaviors of Mg–3Al–1Zn sheets subjected to different loading paths

Abstract Twinning and detwinning are the important deformation modes in magnesium alloys during different deformation processes. To analyze the interaction of two deformation mechanisms under different loading paths, firstly, compression–tension experiments are performed on rolled sheet along the rolling direction. Quasi in-situ electron backscatter diffraction (EBSD) method is used to track the evolution of twinning fraction and texture at exactly observed region. The influence of Schmid factor (SF) value on choosing of twinning and detwinning variants during the above deformation is analyzed, and it is found that twinning and detwinning behaviors are mainly controlled by the variants with maximum SF value. Then, the twinning and detwinning behaviors under multi passes and directions compression are also investigated, which reveal that the secondary twinning can impede the following detwinning.

Multi-Direction-Tunable Three-Dimensional Meta-Atoms for Reversible Switching between Midwave and Long-Wave Infrared Regimes.

We introduce an electromechanically tunable metasurface composed of an array of three-dimensional nanosplit-rings for reversible and large-range changes of optical characteristics in infrared (IR) regime. When a current is induced or withdrawn, each nanosplit ring in the surface can deform in multi directions and consequently become a closed (OFF) or an open (ON) state. Theoretical and experimental results manifest that, as the metasurface is dynamically manipulated between the ON and OFF states, the corresponding resonance absorption will reversibly switch between the long wave (around 10.4 μm) and midwave (around 6.3 μm) IR regimes, two key IR spectral windows, and the reversible relative reflection changes can reach up to 95%.

Surface Feature Extraction Based on Curvelet Transform from Point Cloud Data

Aiming at multi directions analysis problem of surface feature extraction from point cloud data, Curvelet transform is introduced to multi directions analysis of point cloud data. Based on the preprocessing of location and expansion, second-generation discrete Curvelet transform is used to analyze point cloud data. Curvelet transform coefficients are processed to enhance the contour of point cloud data. Nonlinear function is used to process Curvelet transform coefficients of coarse layer. Compromise for soft and hard thresholds is used to process Curvelet transform coefficients of detail layer. Piecewise nonlinear function is used to process Curvelet transform coefficients of fine layer. The data point is reconstructed from the enhanced Curvelet transform coefficient with Curvelet inverse transformation. Initial surface feature is achieved with edge detection. The precise surface feature is achieved with morphological dilation and erosion to filter edge without real shape significance. Example of part point cloud data of brake shell shows the proposed surface feature extraction method can accurately extract surface feature from data point.

Research and Design of Multi-Angle Car Reversing Auxiliary System

According to the current situation and the market needs, an automotive electronics intelligent auxiliary system was designed based on video segmentation technology and OSD display technology. By installing wide viewing fisheye, the system can get the video image information of environment behind the car from multi directions and relieazed 4 splited screens. Thus, vision of dead zone behind the car is maximized and make driving efficiency, safety and comfort are also improved at the same time.

Modal Testing and Parameters' Identification of Spray Boom

In order to research dynamic characteristics of the spray boom, this paper described a modal testing about a self-designed spray boom, the testing introduced the way that multi points and multi directions exciting, one point and one direction response to obtain the FRFs, after importing the dates to the computer, accorded to the stability diagram which calculated based on STAR7 from the obtained FRFs, four physical poles of the spray boom in the band between 0.25Hz and 30Hz were determined, then, two kinds of curve fitting method (POLYNOMIAL, GLOBAL) were used to identify the modal parameters. The result showed: the modal parameters identified through POLYNOMIAL curve fitting method is more accurate. For the first frequency of spray boom is 8.97Hz, in the band of ground exciting frequency. This may lead to spray booms deformation easily. So, to optimize the spray boom by increase the first frequency is necessary.

패턴 합성을 통한 단일 곡면 구조에서의 RCS 감소 기술에 관한 연구

This paper discusses the singly curved phased reflector for reduced RCS pattern, which has minimized RCS level at boresight with a null by phase cancelation and the lowered RCS level of main beam by splitting the main beam into multi directions. Considering the reduced level of boresight and main beam compared to the same sized reference PEC, this proposed multi-beam reflector can be adopted in the mono-static radar and the bi-static radar environment. The proposed reflector is a multi-beam reflector, which has different phase distributions at each row for different steering angle. It is designed through an intermediate stage of a single and dual-beam reflector. The behaviors of the designed reflectors are verified through full-wave simulation and experiment. The reflectors are designed in the frequency of 10 GHz and it has a size () with the curvature k

Emission Spectral Tomography With Optical Fiber Bundle

The real time acquisition of the optical radiation information of multi points in free space is a difficult problem for the optical fluid fields testing. Traditional data acquisition systems are based on multichannel charge coupled device (CCD), with which the optical radiation information from multi directions can be obtained. However these systems are hard to fit the requirement of parallel beam imaging, and hence bring great errors of inverse computations. A multichannel real time data acquisition system based on a digital signal processor (DSP) and a number of optical fiber bundles (OFBs) is proposed in this paper for fluid field reconstructions. Each OFB unit can acquire the optical radiation information that transmits into its entrance aperture via a sensor unit consisting of an optical fiber coupler and a phototransistor. The DSP acts as a main controller that switches on the exposure of all phototransistors synchronously based on the mechanism of electronic shutter. The synchronous sensed signals are locked by a peak hold circuit and then outputted to analog-to-digital converters (ADCs), and therefore the real time acquisition of the optical radiation information of multi points in free space can be realized, which offers the original parallel beam imaging data for the fluid field reconstructions.

1D n–p Heterojunctions of Zinc Oxide on Gallium Nitride: A Structural Characterization

Recently, we showed lateral growth of ZnO nanowires and nanowalls on single crystal GaN and formation of bi- and tridirectional assembly of nanowires and nanowalls using a surface-directed vapor–liquid–solid process (SVLS). Taking advantage of this growth technique, planar arrays of electrically addressable n–p heterojunctions were fabricated. Each n–p heterojunction is formed at the interface of a nanowire or nanowall with the underlying substrate. In the present work, we further investigated the coherency of the crystal structure of the heterojunctions both along their width and length using focused-ion beam microscopy and high-resolution transmission electron microscopy (HRTEM). We explain the anisotropic growth of ZnO in multi directions using a SVLS mechanism, whereas conventional crystal growth techniques only anticipate an isotropic island formation of ZnO on GaN. During the SVLS process, a ZnO nanocrystal forms inside a Au nanodroplet, and elongates via a sequential ZnO island formation during whi...

Penerapan Model Pembelajaran Berlandaskan Pengembangan Kepribadian pada Program Studi Pendidikan Matematika

This classroom action research applied personality based learning which increase students' condition as subject of progressing their personality. The aims of the research were involving personality based learning model for students as mathematics teacher candidate, increasing students' affection, study result based personality, dynamics of students' activities and students' learning process were followed multi directions interactions among students. The main finding of this study, the average of first cycle test was 50,2 and the post-test was 57, difference between them was 6,8. The average of activities and competence performance during first cycle was 6,8 this value was more than success standard i.e. 6,5. The habits of study based personality was not enough planted in themselves, but this was decreased in next cycles. The average of teaching lecturer's performance during first cycle was good enough i.e. 7,1 so that was more than success indicator i.e. 6,5. The average of second cycle was good enough i.e. 72,94 and the difference between them was 5,02 it was more than 5 so standard of success was attained. The average of individual score in team work was 66,67 it was more than minimum success indicator i.e. 6,5. The average of teaching lecturer's performance in second cycle was 8,07 more than first one i.e. 7,33 maybe caused the lecturer was more familiar with this method. Keywords: personality based learning, mathematics teacher candidate

An Interferometric CT for Three-Dimensional Shock Waves Discharged from Two Circular Open Ends.

An interferometric CT (computed tomography) technique is developed to investigate three dimensional phenomena of shock waves in shock tube experiments. Interferograms of shock waves discharged from a pair of circular open ends are taken in the multi directions, and analyzed by the computer aided fringe pattern analysis and CT reconstruction technique. The resultant density distributions show that the present system of the interferometric CT technique is effective for the unsteady shock wave phenomena.

The evaluation of a ?mean? NMR enhancement factor in multidirectional spin systems

In magnetic systems the radio frequency fieldH 1 seen by the nuclei is often enhanced by a factor η. If the atomic spins are distributed in multi directions, as in Bloch walls or spin glasses, one has to consider a spatial distribution η(r) of enhancement factors. The usual way to define a “mean” enhancement factor $$\hat \eta $$ is shown to lead to inconsistent results giving rise to errors up to more than 100%. One has to distinguish between two mean factors, $$\hat \eta (\tau _1 )$$ and $$\hat \eta (H_1 )$$ , depending on measuring conditions. Their deviations from the true value $$\hat \eta _w $$ are discussed.