2019, 8(2):1-10. DOI: 10.12146/j.issn.2095-3135.20181226001
Abstract:With the rapid development of Internet online shopping, automatic classification of product images has become an interesting research topic. In this paper, an accurate classification method for women dress images are investigated. Firstly, 40 000 product images were crawled from the Vipshop online shopping websites, which all are annotated by several experts. Then, several baselines using deep convolutional networks were provided. Finally, a new loss function was introduced and the multi-task learning method was used to improve the classification accuracy. With the comparison of different strategies, the experimental results show that the proposed method can obtain higher classification accuracy.
2019, 8(2):11-22. DOI: 10.12146/j.issn.2095-3135.20180717001
Abstract:Laser lidar and vision sensors are the two mainstream three-dimensional sensing techniques in the applications of robot location and navigation. However, existing low-cost laser lidar usually has low location accuracy and cannot achieve loop closure detection in large areas. In this paper, an indoor robot equipped with low-cost laser lidar and camera was used for experiment. And a novel localization and mapping method was introduced by combing both lidar and image information. An optimization method based on sparse pose adjustment was used to optimize the robot pose by fusing laser points cloud and image feature points as constraints. At the same time, the bag of words model based on visual features was used for loop closure detection. The grid map was optimized by loop closure constraints. Real experimental results show that, the proposed method has better localization accuracy than either laser lidar or vision sensors, and loop closure detection also can be realized.
2019, 8(2):23-36. DOI: 10.12146/j.issn.2095-3135.20180907001
Abstract:There are several problems such as potential security issues, poor transmission performance, low reliability, and heavily dependent on service providers in existing enterprise net-disk based on public cloud. To address these problems, this paper aimes designs a secure enterprise net-disk system, named SkyDisk, based on the multi-cloud servers. SkyDisk provides a full control of files, high-speed data accesses, confidentiality, and reliability for storing the files. Before stored, all files have been encrypted with 256 bit advanced encryption standard, and encoded with Reed-Solomon codes. Each cloud server saves a piece of cipher text of original files, and the files can be recovered even if some servers fail. In addition, parallel transfer of data between local net disk servers and multiple cloud servers can achieve high-speed of upload and download. Finally, SkyDisk implements a Web service, maintains file metadata and user information, and provides users with web access. The test results show that the system can achieve secure and reliable file storage management. At the same time, it can satisfy the functional requirements such as quick upload, download and, convenient file sharing, to reduce the cost of file management and improve production efficiency.
2019, 8(2):37-42. DOI: 10.12146/j.issn.2095-3135.20181008002
Abstract:In this paper, the process steps of plasma-assisted wafer destaticization after plasma etching and destaticization were studied and optimized. Through the data simulation and experimental design, the effects of plate spacing, reaction chamber pressure, radio frequency (RF) power supply and RF power off mode on the residual charge of the wafer were studied. Firstly, the plasma distribution of the reaction chamber in the destaticization process was simulated by Monte Carlo random number method based on software Pegasus. The plasma energy distribution map was studied and the plate spacing and plasma distribution uniformity were analyzed. The relationship had been obtained with the best range of plate spacing. Secondly, the reaction chamber pressure, RF power and plate spacing were used as experimental variables, and the experimental obtained. The results of this paper could be used to optimize the wafer destaticization step and improve process reliability and product yield. group with the lowest residual charge was obtained through experimental design. Finally, based on the experimental group, the RF power supply shutdown mode was optimized. By detecting the potential difference when the wafer was detached from the adsorption device, the optimal RF power supply shutdown mode was
2019, 8(2):43-52. DOI: 10.12146/j.issn.2095-3135.20181211001
Abstract:In this research, a compressible electrode of polypyrrole/carbonized melamine foam (PPy/CMF) based on commercial melamine foam and pyrrole monomer was fabricated by high temperature carbonization and in-situ polymerization. The electrochemical property of compressible PPy/CMF electrode material was investigated by three-electrode system in 1 mol/L sodium perchlorate electrolyte. The volumetric capacitance MFof compressible electrode material can achieve 3 168 mF/cm3 at 2 mA/cm3 and preserve 86.88% of initial capacitance after 1 000 charge and discharge cycles. Furthermore, cyclic voltammetry and galvanostatic charge-discharge curves of compressible electrode material did not change significantly under different compressions, indicating that PPy/CMF is an appropriate compressible electrode with high compressive stability for supercapacitor. These results demonstrate that PPy/CMF is an excellent candidate for compressible supercapacitor.
2019, 8(2):53-65. DOI: 10.12146/j.issn.2095-3135.20181116001
Abstract:The dual-ion battery (DIB) system has attracted great attention owing to its merits of low cost, high energy, and environmental friendliness. However, the DIB based on sodium-ion electrolytes is seldom reported due to the lack of appropriate anode materials for reversible sodium-ion insertion/extraction. Herein, a new sodium-ion based DIB named as SnO2/GF//EG DIB using composite of SnO2 loading on graphene as anode and expanded graphite as cathode is constructed and optimized for the first time. The flexible graphene provides a robust porous structure and proper pore size to accommodate the large volume change of SnO2 nanoparticles, and the continuous graphene network of electrode material also provides better electrical conductivity and more effective lithium ion diffusion path. The material shows excellent cycling stability with high reversible specific capacity (69.9% capacity retention, ca. 279 mAhg－1 after 300 cycles at 1 Ag－1, capacity remains at around 97.4 mAhg－1, 88.5 mAhg－1, 75.5 mAhg－1, 70.4 mAhg－1 and 67.2 mAhg－1 at current densities of 200 mAg－1, 500 mAg－1, 1 000 mAg－1, 1 500 mAg－1 and 2 000 mAg－1, respectively). In a word, we study the electrochemical performance of Tin dioxide composite in the sodium ion based dual ion battery for the first time and the battery with excellent rate capability and cycling stability.
2019, 8(2):66-75. DOI: 10.12146/j.issn.2095-3135.20181114001
Abstract:Noninvasive blood glucose monitoring technology has advantages of painlessness, no infection, and continuous detection, which is an important direction for the development of blood glucose monitoring technology. In order to explore the effects of frequency and glucose concentration on the dielectric properties, the dielectric-frequency characteristics of aqueous solutions with different glucose concentrations are investigated in the frequency range of 500 kHz to 5 MHz. The results show that when the glucose concentration is constant, the real and imaginary parts of the complex permittivity of the aqueous solution decrease in this frequency band as the frequency increases. When the frequency is constant, the real and imaginary parts of the complex permittivity of the aqueous solution decrease as the glucose concentration increases. The results are different from that in high frequency. In addition, the second-order Debye model fitting of the complex permittivity of aqueous solution and the quadratic polynomial fitting of the parameters in the Debye model are studied in this paper. The determination coefficient of all fitting is higher than 0.93, indicating that the model can better represent the dielectric-frequency response characteristics of glucose solution with different concentrations. Finally, a noninvasive blood glucose monitoring model which consists of skin, blood and muscle, was established and the simulation was carried out through finite-difference time-domain. The results indicate that the voltage difference between receiving electrode 2 and 3 increases linearly with the increasing of glucose concentration. We therefore suggest that the proposed frequency between 500 kHz and 5 MHz is feasible in the applications of noninvasive blood glucose monitoring.