Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-31 Cooperative journals: 《农业图书情报学报》
Abstract： [Purpose/Significance] Mining college student data and constructing studnet profiles is conducive to in-depth understanding of students' needs, improving management level, and promoting intelligent service. [Method/Process] Based on the multi-source data mainly generated by the management and service process of colleges and universities, student profiles were developed by focusing on consumption, academic and social indicators, analyzing the characteristics of students, using the Scikit-Learn tool of Python, and applying the K-means clustering algorithms. Empirical research was carried out and representativeness of student portraits from individual and group perspectives was studied. [Results/Conclusions] First, this paper attempts to utilize a new data fusion perspective, by fusing explicit data with implicit data, and generating three-dimensional indicators of consumption behavior, academic behavior, and social behavior. Secondly, in order to solve the problem of single application scenario in previous research, the method of user profile construction is used to realize the fusion of multiple scenarios. Finally, based on the real student data, this study uses K-means clustering algorithm to select groups of students with different characteristics on the basis of previous research. The data of college students is analyzed, and further empirical research is carried out to describe the "consumption-academic-social" profiles of college students. Constructing student profiles from the perspective of multi-source data fusion can effectively provide a basis for decision-making by different units in colleges and universities, such as academic affairs,. Especially in the post-epidemic era, the profiles of college students can detect potential risks in time. The study found that at the individual level, by interpreting the label information of students' portraits, it is possible to understand the 3 aspects of students' consumption, academics and social interaction, and realize dynamic monitoring of individual students. At the group level, through cluster analysis, students with different characteristics can be selected, especially in terms of consumption behavior, and the characteristics of students' activity and stability can be deeply analyzed, which can not only provide a basis for the macro-level observation of students, but also provide new ideas for exploring the correlation between different behavioral elements of students. At the application level, the integration of multi-scenario student profiles can simultaneously realize abnormal identification and early warning, group attention and guidance, and resource planning and adjustment, which greatly broadens the application scenarios of research and improves the energy efficiency of education and teaching management in colleges and universities. However, due to the limitations of data and algorithms, the accuracy and ease of use of student portraits still need to be improved. There are both constraints from practical conditions and insufficient research methods. In future research, more extensive research should be used to improve college student profile construction system, and constantly develop more suitable techniques.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-19 Cooperative journals: 《金属学报》
Abstract： The crystal structure, phase transformations and magnetic properties for Ni50- xCoxMn39Sn11 (x=0, 2, 4, 6) Heusler alloys have been systematically studied by means of structure and magnetism measurements. The results show that with increase of Co concentration, the martensitic transformation temperatures are obviously decreased, while the Curie temperatures of austenite are gradually increased, and they present different structures at room temperature. At the same time, with increasing Co content, the austenitic magnetism rapidly enhances, while the martensitic magnetism almost keeps unchanged. This leads to a significant improvement of difference magnetization (ΔM) between two phases. For Co content added to x=4, the value of ΔM between two phases achieves about 40 Am2/kg and exhibits magnetic field- induced martensitic transformation. Using strain measurement, the strain behavior related to martensitic transition in Ni50-xCoxMn39Sn11 (x=0, 2, 4) samples was studied. It is found that the phase transition strain reaches 0.17% in Ni46Co4Mn39Sn11 sample. Within the magnetic cycles of 3 T, this sample displays a reproducible magnetostrain in temperature range of 215~235 K. Such a reproducible strain could be ascribed to the fact that a partial martensitic transformation of this sample can be driven by isothermal magnetic field.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-08-13 Cooperative journals: 《计算机应用研究》
Abstract： In this paper the system performance of decode-and-forward relay coorperative system under Rayleigh channel and Nakagami-m channel are investigated. combing with the average data packet error rate, formulas for end-to-end spectrum efficiency expression and the stability of system are deduced in double relays system based on source-relay modulation levels. Meanwhile, the effects of different channel parameters m on link spectrum efficiency and system stability are analyzed then the higher order variables of formulas for spectrum efficiency and stability of system under multiple relays system are deduced. Numerical results show that the proposed formulas has better performance than some of the traditional adaptive algorithm.
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