Modelling the Latent Semantics of Diffusion Sources in Information Cascade Prediction

Predicting the information spread tendency can help products recommendation and public opinion management. The existing information cascade prediction models are devoted to extract the chronological features from diffusion sequences but treat the diffusion sources as ordinary users. Diffusion source, the first user in the information cascade, can indicate the latent topic and diffusion pattern of an information item to mine user potential common interests, which facilitates information cascade prediction. In this paper, for modelling the abundant implicit semantics of diffusion sources in information cascade prediction, we propose a Diffusion Source latent Semantics-Fused cascade prediction framework, named DSSF. Specifically, we firstly apply diffusion sources embedding to model the special role of the source users. To learn the latent interaction between users and diffusion sources, we proposed a co-attention-based fusion gate which fuses the diffusion sources’ latent semantics with user embedding. To address the challenge that the distribution of diffusion sources is long-tailed, we develop an adversarial training framework to transfer the semantics knowledge from head to tail sources. Finally, we conduct experiments on real-world datasets, and the results show that modelling the diffusion sources can significantly improve the prediction performance. Besides, this improvement is limited for the cascades from tail sources, and the adversarial framework can help.

Grain Boundary Diffusion Sources and Their Coating Methods for Nd-Fe-B Permanent Magnets

Nd-Fe-B magnets containing no heavy rare earth (HRE) elements exhibit insufficient coercivity to withstand the demagnetization field at elevated temperatures. The grain boundary diffusion (GBD) process provides the best route to fabricate high-coercive Nd-Fe-B magnets with low consumption of expensive HRE resources. Here we give a special review on the grain boundary diffusion sources and their coating methods. Up to now, various types of grain boundary sources have been developed, starting from the earliest Tb or Dy metal. The HRE-M eutectic alloys were firstly proposed for reducing the cost of the diffusion source. After that, the diffusion sources based on light rare earth and even non rare earth elements have also been proposed, leading to new understanding of GBD. Now, the diffusion sources including inorganic compounds, metals, and alloys have been employed in the industry. At the same time, to coat the diffusion source on the magnets before diffusion treatment, various methods have been developed. Different from the previous review articles for GBD, this review gives an introduction of typical types of diffusion sources and their fabrication approaches. The effects of diffusion source on the microstructure and magnetic properties are summarized briefly. In particular, the principles and applicability of different coating approaches were discussed in detail. It is believed that this review can provide a technical guidance for the industry for designing the diffusion process and products meeting specific requirements.

Influence of Hydrostatic Pressure and Cationic Type on the Diffusion Behavior of Chloride in Concrete

The durability of the concrete in underground and marine engineering is affected by the underground and ocean environment. Chloride diffusion coefficient under hydrostatic pressure is a key parameter of concrete durability design under corresponding conditions. Therefore, this paper studies the diffusion behavior of chloride in different diffusion source solutions by experiment and simulation. Based on the experimental results, this paper proposes a new chloride diffusion model under the coupling effect of diffusion and convection. The interaction of ions and compounds in the diffusion source solutions, concrete pore fluid, and concrete material are considered in the new chloride diffusion model. The experimental results show that chloride diffusion rate is significantly affected by hydrostatic pressure, which increases with the increase of hydrostatic pressure. The chloride diffusion coefficient shows a certain difference in difference diffusion source solutions. The chloride diffusion coefficient in divalent cationic diffusion source solutions is the largest, the chloride diffusion coefficient in the divalent and monovalent cationic compound ones is in the middle, and the chloride diffusion coefficient in the monovalent cationic ones is the smallest. There is a linear relationship between the chloride diffusion coefficient and the hydrostatic pressure whether in single or combined cationic diffusion source solutions.

Development Of A Calibration Source For Measurement Of Gaseous Oxidized Mercury In Ambient Air

A HgCl₂ containing diffusion source was evaluated for its potential usefulness as a calibration source for gaseous oxidized mercury (GOM) measurements. Unlike previous calibration sources described in the literature, this source made use of a flow rate of at least 1 L min-¹, and was maintained at a temperature of as low as - 15oC. Under these conditions, the source was found to emit GOM at an environmentally relevant level of 0.0905 pg s-¹, with a GOM fraction of approximately 78%. The source was found to have a consistent response to temperature, a steady state emission level of Hg could be rapidly established and the source was temporally stable. Duplicate sources were compared with one another and found to emit similar levels of Hg under identical sampling conditions. Various methods of cleaning HgCl₂ contaminated items were tested, with the most successful method using a stannous chloride wash solution.

Development Of A Calibration Source For Measurement Of Gaseous Oxidized Mercury In Ambient Air

A HgCl₂ containing diffusion source was evaluated for its potential usefulness as a calibration source for gaseous oxidized mercury (GOM) measurements. Unlike previous calibration sources described in the literature, this source made use of a flow rate of at least 1 L min-¹, and was maintained at a temperature of as low as - 15oC. Under these conditions, the source was found to emit GOM at an environmentally relevant level of 0.0905 pg s-¹, with a GOM fraction of approximately 78%. The source was found to have a consistent response to temperature, a steady state emission level of Hg could be rapidly established and the source was temporally stable. Duplicate sources were compared with one another and found to emit similar levels of Hg under identical sampling conditions. Various methods of cleaning HgCl₂ contaminated items were tested, with the most successful method using a stannous chloride wash solution.

Limitations in the Grain Boundary Processing of the Recycled HDDR Nd-Fe-B System

Fully dense spark plasma sintered recycled and fresh HDDR Nd-Fe-B nanocrystalline bulk magnets were processed by surface grain boundary diffusion (GBD) treatment to further augment the coercivity and investigate the underlying diffusion mechanism. The fully dense SPS processed HDDR based magnets were placed in a crucible with varying the eutectic alloys Pr68Cu32 and Dy70Cu30 at 2–20 wt. % as direct diffusion source above the ternary transition temperature for GBD processing followed by secondary annealing. The changes in mass gain was analyzed and weighted against the magnetic properties. For the recycled magnet, the coercivity (HCi) values obtained after optimal GBDP yielded ~60% higher than the starting recycled HDDR powder and 17.5% higher than the SPS-ed processed magnets. The fresh MF-15P HDDR Nd-Fe-B based magnets gained 25–36% higher coercivities with Pr-Cu GBDP. The FEG-SEM investigation provided insight on the diffusion depth and EDXS analysis indicated the changes in matrix and intergranular phase composition within the diffusion zone. The mechanism of surface to grain boundary diffusion and the limitations to thorough grain boundary diffusion in the HDDR Nd-Fe-B based bulk magnets were detailed in this study.

An observer deployment algorithm for information source positioning based on Naive Bayes

The accurate positioning of the propagation and diffusion source points of personal information is of great practical significance for the protection of personal information security. Currently, a popular method is to locate the data diffusion source point by deploying a certain number of observers and collecting the data propagation information from observers. In view of the deployment of observers, it was found that there is an important correlation between the observer deployment location and the data propagation time delay by analyzing the relationship between the positioning accuracy of information sources and the deployment location of observers, and then an optimal deployment strategy based on Naive Bayes model (NBM) was proposed. At last, it was verified that the proposed deployment strategy can significantly improve the positioning accuracy of information source by comparing the model network with the actual network, which is of great significance for the security control of personal information propagation.