Hasil untuk "Electronics"

Bing Li, Jiangtao Dong, Xile Wang et al.

To investigate the impact of cross-grained sentiments on user feature representation and address the issue of data sparsity, this paper proposes a Personalized Recommendation Algorithm Integrating Cross-Grained Sentiment and Rating Interaction Features (ICSR). The algorithm begins by employing a pre-trained BERT (Bidirectional Encoder Representations from Transformers) model and a Bi-GRU (Bidirectional Gated Recurrent Units) network to derive feature vectors from user and item reviews. Sentiment dictionaries and attention mechanisms are then applied to assign appropriate weights to the review features of users and items, respectively. To capture a richer set of sentiment features, a cross-grained sentiment feature fusion module is introduced. This module leverages an LDA (Latent Dirichlet Allocation) model and dependency syntactic analysis techniques to extract fine-grained sentiment features, while a word2vec pre-trained model and sentiment dictionaries are used to capture coarse-grained sentiment features. These features are then fused to form comprehensive cross-grained sentiment representations. Finally, rating interaction features are extracted using matrix factorization techniques, and all features are integrated and fed into a DeepFM model for rating prediction. Experimental results on Amazon datasets demonstrate that the proposed ICSR algorithm significantly outperforms baseline algorithms in terms of recommendation performance.

Junchao Yang, Ziyang Peng

Countries worldwide are increasingly focused on addressing the imbalance between the supply and demand for EV charging infrastructure, with the community-shared charging post (CSCP) co-construction project emerging as a promising solution. The broad participation and investment support of the residents are the keys to the success of the CSCP co-construction project. This study, grounded in the theory of planned behavior (TPB) from social psychology, incorporated factors such as community identity, perceived green value, economic benefit, uncivil behaviors, and perceived risk to construct a structural model explaining community residents’ intention to invest in the CSCP co-construction project. This research confirmed that (1) 85.73% of respondents expressed strong recognition of the CSCP co-construction project, with a mean recognition score of 5.56 out of a possible 7; (2) an individual’s social-related perceptions, including the subjective norms and community identity are the strongest determinant of the intention to invest in the CSCP co-construction project; (3) the willingness to invest in CSCP co-construction project differs significantly between the EV group and the non-EV group. Economic benefit was significant only for the non-EV group, while uncivil behaviors were significant only for the EV group. These results provide valuable guidelines for governments and corporations that are promoting or pursuing sharing community for the residents.

Li Wei, Lei Zhao, Xun Zhu et al.

In this study, polylactic acid/graphene oxide/Dopamine (PLA/GO/DA) porous nanofiber membrane was prepared by electrospinning. L _16 (4 ^3 ) orthogonal experiment was designed to investigate the effects of reaction temperature, reaction time, and DA concentration on the adsorption performance of DA oxidized and self-polymerized on the fiber. Based on the characterization of scanning electron microscopy and the determination of the adsorption performance of the fiber membrane to methylene blue (MB) dye, data visualization analysis, variance analysis, and F-test were conducted to determine the optimal process parameters: reaction temperature of 45 °C, reaction time of 30 h, and DA concentration of 2 mg ml ^−1 . PLA/GO/PDA(Polydopamine) nanofiber was prepared and characterized under the optimal process parameters. The results showed that the average diameter of the PDA-loaded nanofiber increased from 737 nm to 996 nm, and a layer of PDA with a thickness of about 129 nm was loaded on the outer surface of the fiber, making the contact angle of the fiber membrane with 0° and becoming a hydrophilic material. In adsorption performance testing of MB, the PLA/GO/PDA nanofiber membrane prepared based on the PLA/GO/DA fiber membrane with an adsorption rate of 98.81 % in 24 h was superior to the PLA/GO/PDA nanofiber membrane prepared based on the PLA/GO fiber membrane.

Wonjun Shin, Ji Ye Lee, Jangsaeng Kim et al.

Abstract The need for understanding the low-frequency noise (LFN) of metal oxide semiconductor thin-film transistors (TFTs) is increasing owing to the substantial effects of LFN in various circuit applications. A focal point of inquiry pertains to the examination of LFN amidst bias stress conditions, known to compromise TFT reliability. In this study, we investigate the effects of hot carrier stress (HCS) on zinc tin oxide (ZTO) TFTs by low-frequency noise (LFN) analysis. Asymmetric damage caused by HCS is analyzed by measuring the power spectral density at the source and drain sides. The excess noise generated by the HCS is analyzed with consideration of trap density of states (DOS). It is revealed that the needle defects are generated during the HCS, significantly affecting the LFN characteristics of the ZTO TFTs. Additionally, we observe a self-recovery behavior in the devices and demonstrate the relevant changes in the LFN characteristics following this phenomenon. This study provides valuable insights into the LFN characteristics of ZTO TFTs under HCS conditions and sheds light on the underlying mechanisms.

Gamze Bilgen, Omer Faruk Altuntas

The amount of waste materials such as dredged materials (DM) and waste glass (WG) have been growing exponentially since the middle of the 20th century. The most important problem created by them is the lack of space to be used for storage beside ecological, economic, and environmental problems. The purpose of the presented study is to contribute to the elimination of the mentioned problems by assessing the re-use of related wastes as pavement material. Therefore initially, DM was treated with additives at various contents that are powdered waste glass (GP) (5 %, 10 %, 15 %, 20 %, 25 %), lime (5 %) and cement (5 %). Following, a series of experimental studies and calculations such as Proctor, California bearing ratio (CBR), resilient modulus (MR) were carried out on the blends to define the geotechnical properties of them. Additionally, a cost analysis was made according to the obtained test results and the design inputs for a typical flexible pavement to determine the effect of the additives on the cost of the road construction. The underlying mechanism process of determined effects was defined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The obtained results indicate that CBR of the DM is 5.6 % which means has sufficient strength and stiffness for being used as a subgrade. Increasing the GP content in the blends contributes to achieving more desired results both geotechnically and indirectly economically. Combined use of cement and GP on DM increases the CBR value up to 83 %. This translates to an 89 % reduction in the structural number (SN) and 170 % decrease in cost index. The results of microstructural analysis indicate that the geotechnical improvement of treated DM was provided by CSH and CAH formations. Consequently, the additives used improve index and stiffness properties of DM which means a decrease in the layer thickness in road construction and therefore a decrease in the cost. The presented study confirms the usability of cement, PG, and lime-treated DM as pavement material, according to criteria specified by the Federal Highway Administration.

Jiaquan Li, Kai Wang, Yijiao Jiang et al.

Single‐atom catalysts (SACs) composed of atomically dispersed metal‐active sites embedded in supporting substrates are attracting increasing attention in liquid‐phase selective oxidation reactions with joint merits of both advanced catalytic efficiency and high stability. Co‐based SACs present superior performance in several model oxidative reactions against many other metals, thus they are recognized as a promising solution to the current high‐cost noble‐metal catalysts required for the synthesis of fine chemicals. In this review, the up‐to‐date research on the synthesized Co–SACs in selective oxidation applications is summarized. The strategies of the preparation of Co–SACs with diverse Co‐loading levels and well‐tuned morphologies and chemical structures are showcased, as well as the characterization techniques of the SACs. The applications of Co–SACs in a series of selective oxidation reactions and the influence of different oxidants on the overall reaction efficiency are discussed. In addition, the progress of the mechanism exploration involving active‐site identification, catalytic activation of oxidants, and oxidation pathway elucidation is highlighted. Meanwhile, the existing challenges and the future efforts for the development of the Co–SAC reaction system in selective oxidation processes are outlined.

Zhen Zhang, Kenan Shi, Pan Ge et al.

This paper proposes a kinesthetic–tactile fusion feedback system based on virtual interaction. Combining the results of human fingertip deformation characteristics analysis and an upper limb motion mechanism, a fingertip tactile feedback device and an arm kinesthetic feedback device are designed and analyzed for blind instructors. In order to verify the effectiveness of the method, virtual touch experiments are established through the mapping relationship between the master–slave and virtual end. The results showed that the average recognition rate of virtual objects is 79.58%, and the recognition speed is improved by 41.9% compared with the one without force feedback, indicating that the kinesthetic–tactile feedback device can provide more haptic perception information in virtual feedback and improve the recognition rate of haptic perception.

Feng‐Chang Gu

Abstract Partial discharge (PD) detection is used to evaluate the insulation status of high‐voltage equipment. The most challenging aspect of traditional PD recognition is extracting features from the discharge signal. Accordingly, this study applied the visual geometry group‐19 (VGG‐19) model to gas‐insulated switchgear (GIS) PD image recognition. A high frequency current transformer and an LDP‐5 inductive sensor measured PD electrical signals emitted by 15‐kV GIS. Next, the Hilbert energy spectrum was obtained by Hilbert transform in the time and frequency domains. Compared with a phase‐resolved PD pattern, the Hilbert spectrum can represent the energy and instantaneous frequency with the time variable. Finally, the VGG‐19 model was applied for PD pattern recognition. For validation, its recognition performance was compared with that of a fractal theory by using a neural network method. The VGG‐19 method is straightforward and has a high PD recognition rate, thereby enabling equipment manufacturers to quickly verify the insulation of GIS during assembly or operation.

ZHANG Yi, YANG Qiang, YANG Lin et al.

Combined with the high pressure and high temperature working condition and the characteristics of tooth and sliding ring combined seal, the mathematical model of the rotating slip ring type combined seal is established based on the theory of thermoelastic hydrodynamic lubrication. Furthermore, the elastic deformation of the tooth and sliding ring combined seal under the action of oil film pressure is obtained by the matrix method of deformation influence coefficient based on the theory of small deformation. Combined with the hydrodynamic lubrication equation, the temperature field energy equation and the viscosity temperature equation, the finite difference method is used to solve the thermoelastic flow pressure lubrication model. The oil film thickness distribution and oil film pressure distribution in the working process of the combined seal ring of the toothed slip ring are calculated by MATLAB. The results show that the roughness of the ring has a significant effect on the sealing performance. The film pressure increases first and then decreases in the axial direction, and fluctuates in the stable range in the circumferential direction.Moreover, the oil film thickness and pressure of the sealing ring decrease with the increase of the ambient temperature.

Juan Roberto López Gutiérrez, Pedro Ponce, Arturo Molina

In the science and engineering fields of study, a hands-on learning experience is as crucial a part of the learning process for the student as the theoretical aspect of a given subject. With the COVID-19 pandemic in 2020, educational institutions were forced to migrate to digital platforms to ensure the continuity of the imparted lectures. The online approach can be challenging for engineering programs, especially in courses that employ practical laboratory methods as the primary teaching strategies. Laboratory courses that include specialized hardware and software cannot migrate to a virtual environment without compromising the advantages that a hands-on method provides to the engineering student. This work assesses different approaches in the virtualization process of a laboratory facility, diving these into key factors such as required communication infrastructure and available technologies; it opens a discussion on the trends and possible obstacles in the virtualization of a Real-Time (RT) laboratory intended for Microgrid education in a power electronics laboratory course, exposing the main simulation strategies that can be used in an RT environment and how these have different effects on the learning process of student, as well as addressing the main competencies an engineering student can strengthen through interaction with RT simulation technologies.

Tianli Duan, Kang Xu, Zhihong Liu et al.

A novel facile technique is proposed for fabricating three-dimensional (3D) concave nanolens arrays on a silicon substrate. The technique leverages an inherent characteristic of the polymethyl methacrylate (PMMA) resist during inductively coupled plasma (ICP) etching. The tendency for plasma ions to accumulate at the edge of the PMMA resist helps create a local electric field that causes the ions to etch the sidewall of the PMMA resist. This process progressively increases the uncovered area, resulting in a graded etched depth or a concave structure in the substrate. In addition, using a given ICP etching recipe, the time required for a PMMA resist to be removed by sidewall etching is determined by its width. The use of PMMA resist of different widths enables one to achieve structures of varying etched depths and thus a 3D lens array. Optical characteristics of the fabricated nanolens were simulated using the FDTD (Finite-difference time-domain) method, and focal lengths ranging from 150 nm to 420 nm were obtained. This type of nanolens is very useful in ultraviolet optical devices and CMOS image sensors.

Marco Antonio Contreras-Cruz, Juan Pablo Ramirez-Paredes, Uriel Haile Hernandez-Belmonte et al.

One of the essential abilities in animals is to detect novelties within their environment. From the computational point of view, novelty detection consists of finding data that are different in some aspect to the known data. In robotics, researchers have incorporated novelty modules in robots to develop automatic exploration and inspection tasks. The visual sensor is one of the preferred sensors to perform this task. However, there exist problems as illumination changes, occlusion, and scale, among others. Besides, novelty detectors vary their performance depending on the specific application scenario. In this work, we propose a visual novelty detection framework for specific exploration and inspection tasks based on evolved novelty detectors. The system uses deep features to represent the visual information captured by the robots and applies a global optimization technique to design novelty detectors for specific robotics applications. We verified the performance of the proposed system against well-established state-of-the-art methods in a challenging scenario. This scenario was an outdoor environment covering typical problems in computer vision such as illumination changes, occlusion, and geometric transformations. The proposed framework presented high-novelty detection accuracy with competitive or even better results than the baseline methods.

Rajavel Dhandabani, Shantharajah S. Periyasamy, Padma Theagarajan et al.

This paper deals with the novel approach to generate cubical key that symbolises the message and key in six‐face cubical structure. The cubical message is hybridised to generate the cipher in the encryption. Hybridisation of cubes is performed by using the XOR operation to the six‐face cubical original message and six‐face random sequence which is a part of Key‐Cube. Key‐Cube consists of Rotation Type (RT‐Cube), Rotation Angle (RA‐Cube) and Random Sequence (R‐Cube). As a product cipher technique we generate the S‐Cube and P‐Cube in each of the iterations and it symbolises the substitution and permutation, respectively. Here, total 36 round phase is carried out to generate the final cipher. To guarantee the randomness in each phase of hybridization, cubical message and cubical form of random sequence are shuffled in each of the iterations based on RA‐Cube and RT‐Cube. Cubical message representation, cube hybridisation and shuffling the message using Rubik Cube technique ensure the security hardness in the final cipher. We analysed the strength of our proposed approach by compared the cipher variance with the original message and analysed our encryption technique with well‐known block cipher attaches. The results and analysis show betterment in our proposed approach.

常文治, 毕建刚, 刘姝嫔 et al.

气体绝缘金属封闭开关设备（gas insulated switchgear,GIS）是电力系统中的重要设备,盆式绝缘子作为GIS设备核心绝缘组件,对于GIS设备的安全稳定运行至关重要。盆式绝缘子故障是导致GIS无法正常运行的主要原因,文中设计了气隙缺陷、嵌件毛刺缺陷、单金属颗粒缺陷以及金属颗粒群缺陷四种典型放电缺陷类型,利用有限元静电场数值计算方法建立了252 kV盆式绝缘子的仿真模型。研究了不同典型缺陷模型的电场分布情况,分析了不同缺陷对电场的畸变情况。根据仿真结果设计了四种典型模型的缺陷尺寸参数,为GIS内部缺陷的模拟和试验提供了参考。

Abu ul Hassan Sarwar Rana, Ji Young Lee, Areej Shahid et al.

It is time for industry to pay a serious heed to the application and quality-dependent research on the most important solution growth methods for ZnO, namely, aqueous chemical growth (ACG) and microwave-assisted growth (MAG) methods. This study proffers a critical analysis on how the defect density and formation behavior of ZnO nanostructures (ZNSs) are growth method-dependent. Both antithetical and facile methods are exploited to control the ZnO defect density and the growth mechanism. In this context, the growth of ZnO nanorods (ZNRs), nanoflowers, and nanotubes (ZNTs) are considered. The aforementioned growth methods directly stimulate the nanostructure crystal growth and, depending upon the defect density, ZNSs show different trends in structural, optical, etching, and conductive properties. The defect density of MAG ZNRs is the least because of an ample amount of thermal energy catered by high-power microwaves to the atoms to grow on appropriate crystallographic planes, which is not the case in faulty convective ACG ZNSs. Defect-centric etching of ZNRs into ZNTs is also probed and methodological constraints are proposed. ZNS optical properties are different in the visible region, which are quite peculiar, but outstanding for ZNRs. Hall effect measurements illustrate incongruent conductive trends in both samples.

Pengfei SHAO, Yanwei ZHAO, Zhaoxi FANG

In wireless multicast networks，it is rarely concerned that there may be certain receiving nodes which have better quality links both to the source node and to the other receiving nodes. A novel hash-neighborhoodsearch-network-coding based opportunistic relay retransmission approach was proposed. According to the packet reception status and channel quality，this novel approach dynamically selected the best suitable receiving node whose channel quality was better than the source node as a relay，then hash-neighborhood-search-network-coding strategy was used for the relay to retransmit other receiving nodes’ lost packets. Simulation results show that this novel approach can effectively reduce the number of retransmissions to improve the transmission efficiency with respect to the existing algorithms，especially when one or more of the receiving nodes are interfered and the quality of the channel between receiving nodes and source node continues to decline，this approach can achieve a high retransmission gain.

Javier Ruiz-del-Solar, Rodrigo Verschae, Mauricio Correa

The aim of this work is to carry out a comparative study of face recognition methods that are suitable to work in unconstrained environments. The analyzed methods are selected by considering their performance in former comparative studies, in addition to be real-time, to require just one image per person, and to be fully online. In the study two local-matching methods, histograms of LBP features and Gabor Jet descriptors, one holistic method, generalized PCA, and two image-matching methods, SIFT-based and ERCF-based, are analyzed. The methods are compared using the FERET, LFW, UCHFaceHRI, and FRGC databases, which allows evaluating them in real-world conditions that include variations in scale, pose, lighting, focus, resolution, facial expression, accessories, makeup, occlusions, background and photographic quality. Main conclusions of this study are: there is a large dependence of the methods on the amount of face and background information that is included in the face's images, and the performance of all methods decreases largely with outdoor-illumination. The analyzed methods are robust to inaccurate alignment, face occlusions, and variations in expressions, to a large degree. LBP-based methods are an excellent election if we need real-time operation as well as high recognition rates.

Érica Elisa Dani Wilkens, Luiz Felipe Ferreira

O objetivo deste trabalho consiste em identificar o regime juríco aplicável aos bens digitais no Brasil. Para chegar a tal objetivo busca-se classificar os bens digitais e conceituá-los no âmbito jurídico e no comércio eletrônico. E, por fim, apresentar uma análise sobre os aspectos tributários referentes ao ICMS (Imposto Sobre Circulação de Mercadorias e Serviços) e ao ISSQN (Imposto Sobre Serviços de Qualquer Natureza) em relação aos bens digitais. O estudo caracteriza-se como exploratório, utilizando-se de pesquisa bibliográfica e documental, sendo a abordagem do problema qualitativa. Os resultados da pesquisa apontam que, pela intangibilidade, os bens digitais comercializa dos no meio virtual, isto é, pela Internet, são equiparados aos pro gramas de computador e tributados como serviços. Em relação a não incidência do ICMS ela se dá pelo fato dos bens digitais serem incorpóreos e a noção de mercadoria exigir a materialidade.<br>The objective of this study is to identify the legal regulations which can be applied todigital goods in Brazil. To achieve such objective, the digital goods were classified andconceptualized in the legal field and electronics commerce. Finally, an analysis ispresented, following the taxing aspects of ICMS (stands for ‘Imposto Sobre Circulaçãode Mercadorias e Serviços’ – Service and Goods Circulation Tax) and ISSQN (stands for‘Imposto Sobre Serviços de Qualquer Natureza’ – Services of Any Nature Tax). This studyis considered exploratory once it makes use of a bibliographic and documental research.At the same time, the approach to the problem is qualitative. The results of this researchpoint out the intangibility of digital goods commercialized on the Internet which areconsidered as if they were softwares and are taxed as services. In relation to ICMS, sincethe digital goods are seen as incorporeal, it is not incident because the goods notionrequires a material characteristic.