Feature Generation by Convolutional Neural Network for Click-Through Rate Prediction

Click-Through Rate prediction is an important task in recommender systems, which aims to estimate the probability of a user to click on a given item. Recently, many deep models have been proposed to learn low-order and high-order feature interactions from original features. However, since useful interactions are always sparse, it is difficult for DNN to learn them effectively under a large number of parameters. In real scenarios, artificial features are able to improve the performance of deep models (such as Wide & Deep Learning), but feature engineering is expensive and requires domain knowledge, making it impractical in different scenarios. Therefore, it is necessary to augment feature space automatically. In this paper, We propose a novel Feature Generation by Convolutional Neural Network (FGCNN) model with two components: Feature Generation and Deep Classifier. Feature Generation leverages the strength of CNN to generate local patterns and recombine them to generate new features. Deep Classifier adopts the structure of IPNN to learn interactions from the augmented feature space. Experimental results on three large-scale datasets show that FGCNN significantly outperforms nine state-of-the-art models. Moreover, when applying some state-of-the-art models as Deep Classifier, better performance is always achieved, showing the great compatibility of our FGCNN model. This work explores a novel direction for CTR predictions: it is quite useful to reduce the learning difficulties of DNN by automatically identifying important features

Micro Friction Experimental Study Based on Parallel Cantilever

AbstractIn this paper, the law of micro-friction in meso-scale is studied, one optical testing method of micro friction based on the structure of parallel cantilever is given and the testing system is designed, the composition of test system, testing method, the design of force sensor, the testing method and the calibration of force sensor are introduced. The force sensor is calibrated and the deformation of sensor is measured by light reflection. Then the micro friction is obtained by analyzing data. The results of experiment show the resolution of specification of micro friction testing is 10μN, which could meet the demands of micro friction testing with short stroke and high resolution and realize the precise test of micro friction, and the same time it has been analysed which load is unstable during testing

Study on cutting performance of SiCp/Al composite using textured YG8 carbide tool

Precision machining of SiCp/Al composites is a challenge due to the existence of reinforcement phase in this material. This work focuses on the study of the textured tools’ cutting performance on SiCp/Al composite, as well as the comparison with non-textured tools. The results show that the micro-pit textured tool can reduce the cutting force by 5–13% and cutting length by 9–39%. Compared with non-textured tools, the cutting stability of the micro-pit textured tools is better. It is found that the surface roughness is the smallest (0.4 μm) when the texture spacing is 100 μm, and the residual stress can be minimized to around 15 MPa in the case of texture spacing 80 μm. In addition, the SiC particles with size of around 2–12 μm in the SiCp/Al composite may play a supporting role between the texture and the chips, which results in three-body friction, thereby reducing tool wear, sticking, and secondary cutting phenomenon. At the same time, some SiC particles enter into the micro-pit texture, so that the number of residual particles on the surface is reduced and the friction between the tool and the surface then decreases, which improves the surface roughness, and reduces the surface residual stress.TU Berlin, Open-Access-Mittel - 202

Research on the micro-hole texture forming of PCD tool surface

Based on the research on the forming mechanism of textured PCD tool surface, the nanosecond laser is used to study the influence of laser machining parameters on the size and topography of PCD tool surface micro texture. The micro-hole texture is prepared on the surface of the PCD tool, and a single factor experiment is designed to study the influence of laser power, pulse frequency and defocusing amount on the micro-hole texture. The results show that, the micro-hole diameter increases gradually with the laser power, but decreases with the pulse frequency; the overall micro-hole diameter tends to increase with the defocus. The pulse frequency has the greatest impact on the micro-hole diameter, followed by the defocus amount, and finally the laser power. The influence of different parameters on the surface recast layer is also completely different. As a result, the surface and laser power are the main factors that affect the surface recast layer

Emulsion Electrospinning of Polytetrafluoroethylene (PTFE) Nanofibrous Membranes for High-Performance Triboelectric Nanogenerators

Electrospinning is a simple, versatile technique for fabricating fibrous nanomaterials with the desirable features of extremely high porosities and large surface areas. Using emulsion electrospinning, polytetrafluoro­ethylene/polyethene oxide (PTFE/PEO) membranes were fabricated, followed by a sintering process to obtain pure PTFE fibrous membranes, which were further utilized against a polyamide 6 (PA6) membrane for vertical contact-mode triboelectric nanogenerators (TENGs). Electrostatic force microscopy (EFM) measurements of the sintered electrospun PTFE membranes revealed the presence of both positive and negative surface charges owing to the transfer of positive charge from PEO which was further corroborated by FTIR measurements. To enhance the ensuing triboelectric surface charge, a facile negative charge-injection process was carried out onto the electrospun (ES) PTFE subsequently. The fabricated TENG gave a stabilized peak-to-peak open-circuit voltage (<i>V</i>_oc) of up to ∼900 V, a short-circuit current density (<i>J</i>_sc) of ∼20 mA m^–2, and a corresponding charge density of ∼149 μC m^–2, which are ∼12, 14, and 11 times higher than the corresponding values prior to the ion-injection treatment. This increase in the surface charge density is caused by the inversion of positive surface charges with the simultaneous increase in the negative surface charge on the PTFE surface, which was confirmed by using EFM measurements. The negative charge injection led to an enhanced power output density of ∼9 W m^–2 with high stability as confirmed from the continuous operation of the ion-injected PTFE/PA6 TENG for 30 000 operation cycles, without any significant reduction in the output. The work thus introduces a relatively simple, cost-effective, and environmentally friendly technique for fabricating fibrous fluoropolymer polymer membranes with high thermal/chemical resistance in TENG field and a direct ion-injection method which is able to dramatically improve the surface negative charge density of the PTFE fibrous membranes

Recent progress in bio-inspired macrostructure array materials with special wettability—from surface engineering to functional applications

Bio-inspired macrostructure array (MAA, size: submillimeter to millimeter scale) materials with special wettability (MAAMs-SW) have attracted significant research attention due to their outstanding performance in many applications, including oil repellency, liquid/droplet manipulation, anti-icing, heat transfer, water collection, and oil–water separation. In this review, we focus on recent developments in the theory, design, fabrication, and application of bio-inspired MAAMs-SW. We first review the history of the basic theory of special wettability and discuss representative structures and corresponding functions of some biological surfaces, thus setting the stage for the design and fabrication of bio-inspired MAAMs-SW. We then summarize the fabrication methods of special wetting MAAs in terms of three categories: additive manufacturing, subtractive manufacturing, and formative manufacturing, as well as their diverse functional applications, providing insights into the development of these MAAMs-SW. Finally, the challenges and directions of future research on bio-inspired MAAMs-SW are briefly addressed. Worldwide efforts, progress, and breakthroughs from surface engineering to functional applications elaborated herein will promote the practical application of bio-inspired MAAMs-SW

Evolution of blue carbon management policies in China: review, performance and prospects

Since 1982, China’s blue carbon management policies have made significant contributions to blue carbon’s development. Blue carbon is carbon captured and stored by marine ecosystems and it plays an important role in addressing climate change. Analyzing the evolution of blue carbon management policy is necessary to understand its potential to contribute to climate action, and to improve its management and maximize its effectiveness. This paper considers these issues in China. It used content analysis and ROSTCM6 software to empirically analyze 82 blue carbon management policy documents from China. The evolution of relevant policies and their performance is as follows: First, policy focus has gradually shifted from protecting blue carbon ecosystems to increasing blue carbon stocks; second, policy participants became increasingly diversified; and third, the policy approach has changed from simple protection to comprehensive, integrated land use – marine system management. Although the Chinese government has made progress in blue carbon management policies, it still faces many challenges including blue carbon ecosystem protection; legal status; trading mechanisms; and international cooperation. The development of future blue carbon management policy should focus on optimizing the land use structure of coastal zones, on promoting environmental legislation highlighting blue carbon issues, on supporting the establishment of blue carbon trading mechanisms, and on strengthening its international cooperation in this arena. Key policy insightsChina’s blue carbon management approaches shows that relevant policies contribute greatly to addressing climate change and sustainable development. This provides new theoretical support to promote future development of blue carbon management policies.Establishing a blue carbon trading mechanism provides economic incentives for its management.Blue carbon’s property rights, accounting standards, and trading entities need to be further clarified.A detailed legal definition of blue carbon is needed to ensure that appropriate penalties are imposed for the destruction of blue carbon ecosystems. China’s blue carbon management approaches shows that relevant policies contribute greatly to addressing climate change and sustainable development. This provides new theoretical support to promote future development of blue carbon management policies. Establishing a blue carbon trading mechanism provides economic incentives for its management. Blue carbon’s property rights, accounting standards, and trading entities need to be further clarified. A detailed legal definition of blue carbon is needed to ensure that appropriate penalties are imposed for the destruction of blue carbon ecosystems.</p

Study on the tool setting method of micro-milling tool based on in-line holography

Aiming at the various shortcomings of existing tool setting methods, this paper proposes a coaxial holographic tool setting method for tiny tools. Based on the research and analysis of the principle of holographic imaging and the key issues of holographic images, a set of holographic tool setting detection device for micro milling tool was built, and the micro milling tool measurement was carried out on the five-axis machining center using standard tools. experiment. Experimental results show that the tool setting device can efficiently perform tool setting detection of micro-milling tool. Compared with the measurement results of the high-precision external presetting instrument, the relative error of the contact tool setting instrument is 0.033%, and the relative error of the holographic tool setting prototype is 0.007%, which is more effective in realizing the tool setting of tiny tools. Detection. This result verifies the feasibility of the coaxial holographic tool setting method for micro tool, that is, holographic measurement can be used for high-precision tool setting of micro milling tool

Sharpness evaluation of microscopic detection image for micro parts

According to the characteristics of micro parts microscopic detection image, including the image texture is similar, the edge information is too little and the gray distribution Range is limited, based on the basic principles of algorithm, analyzes the traditional sharpness evaluation function. Aiming at the defect that the traditional sharpness evaluation function cannot have both high sensitivity and noise immunity, an algorithm based on local variance information entropy is proposed. The method uses the local variance to weight the self-information of each gray level, on the one hand, it makes up for the lack of spatial information of information entropy and avoids misjudgement of sharpness; on the other hand, it can increase the weights of clear region pixels when they participate in the calculation of information, while reducing the weights of background and noise region pixels, thereby improve the function sensitivity. The experimental results show that compared with the traditional sharpness evaluation function, the local variance information entropy function not only has high sensitivity, but also has better noise immunity and is suitable for actual auto-focusing systems