Table of Content

30 August 2016, Volume 22 Issue 4

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Design and experiment of a 915 MHz printed rectifier with adaptive power

LU Jiajun, YANG Xuexia, DI Luqi

2016, 22(4):  381-387.  doi:10.3969/j.issn.1007-2861.2014.05.019

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This paper proposes an adaptive power rectifier at 915 MHz operating in a wide range of low input power. A field effect transistor works as an adaptive switch for changing the working modes of the rectifier according to the input power level. As a result, the rectifier can achieve high MW-DC conversion efficiency over the entire range. A double-stub matching network matches the input impedance of the diode to 50 . A shunted capacitor works as a DC-pass filter to smooth the output DC power. Simulation results show that efficiency is above 40% within an input power range from −16 to 4 dBm, and the maximum efficiency is 66.2%. The measured center frequency shifts a litter and the maximum efficiency is 47.5%. The rectifier is fabricated using a simple planar printed circuit board (PCB) technique, and is easy to be integrated. It can be used to collect ambient electromagnetic energy.

Robust audio watermarking based on eigen-value decomposition

TONG Renting1, CHENG Hang1,2, ZHANG Xinpeng1

2016, 22(4):  388-397.  doi:10.3969/j.issn.1007-2861.2014.05.017

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Common digital signal processing often introduces noise into audio signals and cause high-frequency distort. Meanwhile, both signal processing operations and malicious attacks may change location of watermark information. By making use of robustness of eigen-value decomposition (EVD), a blind audio watermarking algorithm is proposed. The original audio signal is divided into two parts. Binary codes for synchronization are embedded into the first part using quantization index modulation (QIM). The approximation components of discrete wavelet transform (DWT) of the second part is transformed using EVD to generate a diagonal matrix, and the watermark information is embedded into the matrix entries with QIM. Experimental results show that embedding capacity of the proposed method is as high as 172 bit/s, and it still maintains good audio quality and can tolerate a wide range of common attacks.

Design and implementation of FFT/IFFT processors with word-length optimization for OOFDM-PON system

WANG Kai, WU Qi, LI Jiaqi, XUE Ziwei, ZHANG Junjie

2016, 22(4):  398-407.  doi:10.3969/j.issn.1007-2861.2014.05.018

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High-speed parallel fast Fourier transform/inverse fast Fourier transform (FFT/IFFT) module has become one of the most significant obstacle to practically developing realtime high-speed optic orthogonal frequency division multiplexing (OOFDM) system based on field programmable gate array (FPGA) platform due to its high complexity. This paper builds a simulation platform for OOFDM transceivers and realizes joint optimization of the IFFT and FFT module to reduce logic resource usage. The algorithm shortens word-length boundaries to reduce the time for searching optimized word-length and builds a mapping
table of the optimal word-lengths. Error between simulation results and verification results on an offline platform is within 0.5 dB indicating correctness of the proposed optimization algorithm. In addition, the FFT module based on the mapping table saves about 37.2% resource compared to the Spiral design.

LMI based approach for finite-frequency model order reduction of continuous-time linear time-delayed systems

DU Xin1, FAN Peibing1, LIU Fuwei2

2016, 22(4):  408-420.  doi:10.3969/j.issn.1007-2861.2015.04.014

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Model order reduction of continuous-time linear time-delayed systems over limited frequency intervals is discussed in this paper. The approximation performance is characterized by introducing an index associated with the finite-frequency maximum singular value of the error transfer function. With the aid of some fundamental matrix inequality techniques, sufficient criterion for stability of the reduced-order model and optimizing finite-frequency approximation error is derived. The model order reduction problems can be tackled by solving the corresponding linear matrix inequalities (LMIs) based optimization problems. A numerical example is given to show effectiveness of the proposed technique.

Kinect-based object grasping by robot arm hand system

DING Meikun, XU Yulin, JIANG Caijun, RAN Peng

2016, 22(4):  421-431.  doi:10.3969/j.issn.1007-2861.2016.04.008

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To realize automatic object grasping by a robot arm hand system, Kinect is used for real-time detection of the object. The Zhang Zhenyou chessboard method is applied to calibrate the intrinsic and external parameters of the Kinect. Depth segmentation is done to filter out most of the background interference, and identification and location of object are achieved based on the color and shape features. The object’s 3D coordinates is sent to the manipulator console to locate the target position through TCP/IP communication. A changing integration PID algorithm is applied to achieve fast and accurate grasp by controlling pressure on the dexterous hand. An experiment system is developed to verify effectiveness of the proposed methods.

Mechanical scheme design of a humanoid facial expressions robot

LU Kongbi, KE Xianxin, SHANG Yufeng

2016, 22(4):  432-439.  doi:10.3969/j.issn.1007-2861.2014.04.011

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To give richer facial expressions to humanoid countenance robot therefore achieve more harmonious interaction with people, a mechanical design of humanoid expressions is proposed by analyzing the generation of basic expressions and muscle movements, providing a hardware platform support for further study. The robot head consists of the mechanisms of eyebrows, eyelids, eyeballs, and neck, as well as the mechanism of jaw for mastication movement. Their working principles are described in detail, and several design choices are compared. The choice of mechanical design is finally made, and the required further research is specified.

Data editing techniques of ternary optical adder implementing M+B

SHEN Yunfu, ZHANG Kaikai, JIANG Benpeng

2016, 22(4):  440-448.  doi:10.3969/j.issn.1007-2861.2015.01.001

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Due to carry propagation, efficiency of addition for data with large number of bits has not been significantly improved in the existing computers. Optical approaches have advantages in parallel and carry free addition with a large number of data bits. Based on the computing principle of M+B and the three ternary transforms of C, P and R as proposed in previous works, this paper studies related data editing techniques in which M is an MSD number, B is binary number. A data editing technique for this type of addition is proposed. Simulation is carried out on the three ternary transforms C, P and R for addition, data truncation and data concatenation. The results validate correctness of the proposed data editing technique.

Design of parallel photosensitive array in ternary optical computer decoder

SHI Yeqiang, JIN Yi, OUYANG Shan, ZHAN Haojun

2016, 22(4):  449-460.  doi:10.3969/j.issn.1007-2861.2015.01.004

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This paper discusses the design of a parallel photosensitive array for a decoder in a thousand-bit ternary optical computer. The strategy is to make a parallel module with 16 photosensitive pixels and circuits, and joint some modules into a utility parallel photosensitive array. Each module transforms 16 three-state optical signals from a ternary optical processor into 16 two-state electoral signals concurrently. A parallel photosensitive array then transforms thousands of three-state optical signals into electoral signals concurrently. Thus the module becomes a low-cost, maintainable and replaceable parallel photoelectric device. Experiments are performed to verify stability and correctness of the photosensitive pixels and their circuits. A test on four samples of the module outline shows that splicing a large-scaled photosensitive array with lots of modules is convenient.

A class of extension of the Young inequality

WU Shujun1,2, SHI Zhongrui1

2016, 22(4):  461-468.  doi:10.3969/j.issn.1007-2861.2015.01.014

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The proof of a revise for Theorem 1.10 in Geometry of Orlicz Spaces is presented. A class of extension of the Young inequality is then established based on the revision to improve the Young inequality.

New exact solutions of some nonlinear fractional partial differential equation

LIU Yinlong, XIA Tiecheng, LIU Zeyu

2016, 22(4):  469-476.  doi:10.3969/j.issn.1007-2861.2014.05.021

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By using an improved method of fractional sub-equation, some nonlinear fractional evolution equations are solved including fractional Burgers equation, coupled fractional Burgers equation and fractional Klein-Gordon equation. New exact solutions of these nonlinear fractional nonlinear evolution equations are obtained.

Semi-parametric ordinal variable regression model

XIONG Di, HE Youhua

2016, 22(4):  477-485.  doi:10.3969/j.issn.1007-2861.2014.04.010

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Based on a proportional odds model, the ordinal variable regression model is generalized, a semi-parametric ordinal regression model is established, and consistency of the estimators both in linear and nonlinear parts are proved in this paper. Simulation is conducted to analyze the correct rate and mean square error in the semi-parametric ordinal variable regression model with different sample sizes. The result shows that the semi-parametric ordinal regression model has high accuracy even with small samples. Compared to the number of observation points, the repeat number of experimental points has greater influence on accuracy. Calculation of the grain price warning problem shows that the semi-parametric ordinal regression model provides better extrapolation results than the proportional odds model.

Dynamic analysis of electro-active polymer cylindrical shells

WANG Chengmin1, REN Jiusheng2,3

2016, 22(4):  486-496.  doi:10.3969/j.issn.1007-2861.2014.05.022

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Based on the theory of finite elasto-dynamics, motion and destruction of an electro-active polymer cylindrical shell subject to suddenly applied internal pressure and an electric field are studied. A nonlinear differential equation describing the motion of the shell’s inner surface is developed. Numerical computation and qualitative dynamic analysis are conducted. It is shown that nonlinear periodic oscillation exists when the internal pressure is less than a critical value. When the pressure exceeds the value, the shell is destroyed. The effects of electric field, internal pressure and thickness of the shell on oscillation are discussed by examining vibration amplitudes, phase diagrams and periods.

Partial pressure and diffusion flux of dissolved carbon dioxide in mainstream and tributary (Zhuyi River) of the Three Gorges Reservoir in summer

WEI Haobin1, WU Xueqian1, CAO Man1, FU Jianan1, JIA Xiaobin1, DENG Bing2, WANG Fushun1

2016, 22(4):  497-504.  doi:10.3969/j.issn.1007-2861.2015.01.011

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The mainstream and tributary of the Three Gorges Reservoir were investigated from May 2013 to July 2013 to understand the distribution of the partial pressure of carbon dioxide. The results show that, along the water column of the tributary (Zhuyi River), the lowest value of the partial pressure of carbon dioxide appears in surface water, and increases rapidly with depth. Below 10 meters in depth, the partial pressure of carbon dioxide becomes stable. There are significant differences of the partial pressure of carbon dioxide in surface water between mainstream and tributaries. During the period of investigation,
the partial pressure of carbon dioxide in the surface water of the mainstream is 220.8~268.0 Pa, with an average CO₂ emission fluxes of 51.05 mmol·m⁻²·d⁻¹. The partial pressure of carbon dioxide in the surface water of tributary (Zhuyi River) is 14.9~190.3 Pa. Emission flux of CO₂ in the three months are 0.42, −0.12 and 20.83 mmol·m⁻²·d⁻¹. The result indicates that the tributary Zhuyi River emits less CO₂ than the mainstream.

Experiments on loess as intermediate cover in landfills in northwest China

SHI Wei1, CHAI Xiaoli2

2016, 22(4):  505-514.  doi:10.3969/j.issn.1007-2861.2015.03.019

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The functions of intermediate covering layer of landfill include temporary enclosure of garbage, control of rainfall infiltration, reducing mosquito breeding, etc. High density polyethylene (HDPE) film is easy to pierce to cause rain infiltration, but the cost is high. The northwest area of China is dry, with loess widely distributed. It is convenient to be used as a landfill intermediate cover. Experimental studies are carried out on tamping construction, impervious performance and impervious performance deterioration after wetting and drying cycles. The results show that the saturated permeability coefficient of loess increases with increasing dry density. Dry density reaches 1.60 g/cm³ when its permeability is from 10⁻⁷ cm/s to 10⁻⁶ cm/s. The field double ring in situ experimental permeability coefficient is 8.37×10⁻⁸ cm/s, about double as in the indoor test. With the natural drying wetting cycle condition of saturated infiltration coefficient being 1.18×10⁻⁶ cm/s, it is 14 times greater than the condition without crack. Adding a soil vegetation layer with thickness of 15 cm, cracking of loess is suppressed.

Synthesis of organism-based zinc-iron bimetallic catalyst by sol-gel and its visible photocatalytic activity to dyeing effluents

RUAN Xiuxiu, ZUO Jianwei, CHEN Hua, XU Nannan, YANG Erwei

2016, 22(4):  515-523.  doi:10.3969/j.issn.1007-2861.2015.04.009

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Zinc acetylacetonate and iron acetylacetonate are used as sources of organic zinc and organic iron to successfully synthesize a new type of organism-based zinc-iron bimetallic material using the sol-gel method. This organic material has wonderful photocatalytic performance for degrading organic contaminants in water. Several techniques including X-ray diffraction (XRD), elemental analysis (EA), UV-Vis diffuse reflection spectrum(UVPC), inductively coupled plasma emission spectrometry (ICP-AES) and Fourier transform infrared spectroscopy (FT-IR) are used to analyze its structure and composition. It is found that this organism-based zinc-iron bimetallic material has a layered structure with a layer distance of about 8.74 nm. Contents of iron, zinc and carbon of the material are 8.39%, 25.73% and 39.64%, respectively. The material contains metal-oxygen bond and acetylacetone. Photo-catalytic activity and selectivity of the photocatalysts are evaluated by visible photo-catalytic degradation of Congo Red, Rhodamine B and aniline, respectively standing for anion organic, cationic organic and non-ionic organic. The photocatalytic degradation rate of anion organic Congo Red reaches 99 mg/g by the catalyst under sunshine, the cationic organic Rhodamine B reaches 36 mg/g, and the non-ionic organic aniline is only 32 mg/g. Therefore, its selective photocatalysis performance of anionic
dyes is the best.

Dynamic pricing of conspicuous goods

WEN Xiaoqin, HAN Guangyao

2016, 22(4):  524-532.  doi:10.3969/j.issn.1007-2861.2016.02.002

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This paper studies the pricing strategy of luxury goods in a strong market and a weak market with the revenue management theory. Optimal pricing models are first established in a two-stage sales period. Based on theoretical and numerical analysis of the models, with unlimited production capacity, the vendors choose to set a higher price in the first phase and a lower price in the second phase in a strong market. A strong market has a positive impact on the expected revenue of the sellers. However, a weak market is quite different. It has a negative effect on the expected revenue of the sellers. To make maximum gains, the vendors cannot have a too high price tag in a weak market.