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Introduction to Knowledge Graphs
A knowledge graph is a large-scale semantic network that represents the real world in a semantic format. It represents entities as nodes, and the properties of entities and the relationships between entities as edges, forming a network structure. This structured form is recognizable by humans and friendly to machines, facilitating machine understanding. The large-scale concepts, attributes, and relationships between entities in the graph provide rich semantic information and associations, inherently possessing various characteristics of graphs, enabling relevant operations and applications. Once constructed, it can also serve as background knowledge for downstream applications. Initially proposed by Google, the knowledge graph was primarily used to improve the capabilities of search engines and enhance search quality. Due to its unique characteristics, the knowledge graph plays an important role in various aspects of artificial intelligence.

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Construction of Subject Knowledge Graphs in Education
The construction of knowledge graphs is typically application-oriented. Before constructing a graph, it is essential to clarify the problems to be solved and the knowledge required to address these problems, and then design the ontology of the knowledge graph to cover this knowledge. First, let’s introduce some common application scenarios and logic of educational knowledge graphs, design the ontology of the educational graph based on these applications, and then further construct the knowledge graph.
(1) Application Logic of Educational Knowledge Graphs
The educational knowledge graph centers around subject knowledge, establishing hierarchical relationships between knowledge points of various subjects, the connections between knowledge points, and the sequential relationships between different knowledge points, forming a subject knowledge graph. This graph can visually display the relationships between knowledge points to students, making it clear and intuitive, and can naturally help students construct a knowledge system, reference key knowledge points, discover associations between knowledge points, and assist students in summarizing and eliminating knowledge blind spots.
After constructing the subject knowledge graph, it can be associated with teaching resources (textbooks, exam questions, handouts, teaching videos, test papers, etc.), and through user information and learning records, establish connections between knowledge points and users. Utilizing the knowledge graph allows for a more precise characterization of students’ knowledge mastery and a more accurate depiction of resources. This enables precise academic assessments of users, learning path planning, and personalized recommendations for learning resources.
It can also help teachers better understand students’ academic situations, optimize teaching methods, and adjust teaching strategies. By associating with teaching research materials, proactively recommending teaching research can enhance the efficiency and quality of teachers’ preparation. A teaching assistance system centered around knowledge graph Q&A can effectively reduce the burden of repetitive questions on teachers and greatly meet students’ inquiry needs.
(2) Construction of Educational Knowledge Resources Based on Subject Knowledge Graphs
The construction of educational knowledge resources centered on knowledge graphs establishes associations between domain knowledge, linking knowledge points with various educational resources such as different versions of textbooks, teaching aids, handouts, videos, and exam questions to form a comprehensive network. These association networks support upper-level applications.
In the subject knowledge graph of the education field, the relationships between knowledge mainly include: hierarchical relationships, primarily between parent and child concepts, and between concepts and entities. The concept graph expresses the relationships between concepts in the education field. There are many conceptual contents in the education field, and the relationships between these concepts form the entire knowledge framework. Inclusion relationships refer to specific sub-topics under a knowledge point, representing the whole and parts. Sequential relationships can be used for learning planning. In different subjects, there are also some special relationships, such as mutual exclusivity and causality, which need to be refined and clarified by domain experts and knowledge engineers during the actual construction of graph resources.
Knowledge in educational graphs also has rich attributes, such as common attributes like “exam points,” “difficult points,” “common mistakes,” and “exam syllabus requirements.” Different subjects have specific fine-grained attributes, such as “definition,” “properties,” “area formula,” and “perimeter formula” in mathematics.

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Applications of Knowledge Graphs in Smart Education
(1) Precision User Profiling Based on Educational Knowledge Graphs
Precision user profiling based on educational graphs extracts key information from user behavior data and their connections with various resource objects to characterize users. User profiles based on knowledge graphs can enhance the data of user profiles, providing a more comprehensive and precise characterization of users.
1. Precision User Profiles
User profiling technology should be quite familiar by now, as it aims to better characterize users for understanding them, essentially “tagging” them. The accuracy of user profiles determines how accurately users can be understood. In practical applications, two main issues need to be addressed: the first is incomplete profile data, and the second is incorrect profile data.
To address these issues, knowledge graphs can be utilized. The nodes in knowledge graphs abstract the knowledge of the education field, covering a sufficient number of entities and concepts, serving as a source of tags for user profiles. The high quality of these tags ensures their accuracy. These tags are interconnected, and the graph contains rich semantic relationships, helping machines understand the meanings of these tags. The user-friendly structure facilitates better human understanding and the intuitive discovery of relationships between tags. Algorithms such as tag propagation and cross-domain recommendations can be used to mine more precise tags to describe users, enriching user tags and enhancing user accuracy. Additionally, when creating user profiles, they can be visualized as products, generating personalized, dynamically changing user knowledge graphs using the relationships in the graph.
2. Precision Academic Situation Analysis
Knowledge graphs can enable more precise analysis of academic situations. Traditional educational experts (teachers’ experiences) rely heavily on experience to assess learners’ knowledge and ability statuses, lacking the integration of educational measurement concepts, which results in significant randomness and subjectivity. Using knowledge graphs and big data analysis methods can objectively mine learners’ learning processes from multiple dimensions. The data can be mined from various dimensions, not limited to test scores, error logs, and learning records, revealing knowledge mastery and weak knowledge as explicit features. It can also extract deeper learning speeds, learning preferences, cognitive levels, and other implicit features, making the analysis results more personalized and objective.
For unmet learning objectives, knowledge graphs can be used for root cause analysis, identifying weak points and related knowledge points, effectively filling gaps in knowledge. The diagnostic process is more adaptive and personalized.
(2) Enhancing Teaching Quality and Efficiency
Knowledge graphs in assisted teaching applications help teachers with lesson preparation, teaching research, question creation, and exam analysis. The system can recommend similar related materials (lesson plans, course explanations, assignments, etc.) to improve teachers’ teaching efficiency, and graph-based searches can return the required content more accurately.
1. Intelligent Lesson Preparation
By utilizing subject knowledge graphs, the system links subject knowledge points with textbooks, handouts, exercises, etc., and continuously pushes suitable lesson preparation resources based on teachers’ teaching progress and textbook versions, allowing for quick and accurate retrieval of required resources to enhance lesson preparation efficiency and quality. In addition to lesson preparation, subject knowledge graphs can also assist in intelligent question creation and exam analysis.


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The Evolution Path of Education Intelligence Centered on Knowledge Graphs
Knowledge graphs are increasingly taking on the mission of assisting the intelligentization of industries. Exploring the evolution path of industry intelligentization based on knowledge graphs is therefore crucial. After years of practice, this path has become clearer, presenting an iterative development model of knowledge resource construction and knowledge application. The fundamental principles for implementation are: overall planning, application-driven, and promoting construction through application. The iterative development path of knowledge resource construction and knowledge application.

(Source: Hexi University)
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