ノード classification is a key task in the field of graph-based 機械学習, where the objective is to assign labels or categories to nodes within a graph. A graph consists of nodes (also called vertices) connected by edges, representing relationships or interactions between them. Examples of graphs include social networks, citation networks, and biological networks.
In node classification, each node typically has associated features, which can be numerical or categorical data that describe various attributes of the node. The classification process involves utilizing these features, along with the graph’s structure (i.e., the connections between nodes), to infer the correct category for each node. This task can be performed using various 機械学習技術, including supervised, semi-supervised, and 教師なし学習 方法において重要なタスクです。
教師ありノード分類は ラベル付きデータ, where some nodes come with known categories. The classifier learns from this labeled data to make predictions for unlabeled nodes. 半教師あり学習, on the other hand, leverages both labeled and unlabeled data, which is particularly useful in scenarios where obtaining labels is expensive or time-consuming. Unsupervised methods might cluster nodes based on their features or connectivity without prior labels.
Node classification has numerous applications, such as identifying communities in social networks, classifying products in recommendation systems, 不正行為の検出, and analyzing biological networks to understand disease mechanisms. With the advent of deep learning techniques, particularly グラフニューラルネットワーク (GNNs), node classification has become more effective, enabling the modeling of complex relationships within graphs.