Examinando por Materia "Neo4j"
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- Artículo de Publicación PeriódicaA model and query language for temporal graph databases(2021-09) Debrouvier, Ariel; Parodi, Eliseo; Perazzo, Matías; Soliani, Valeria; Vaisman, Alejandro Ariel"Graph databases are becoming increasingly popular for modeling different kinds of networks for data analysis. They are built over the property graph data model, where nodes and edges are annotated with property-value pairs. Most existing work in the field is based on graphs were the temporal dimension is not considered. However, time is present in most real world problems. Many different kinds of changes may occur in a graph as the world it represents evolves across time. For instance, edges, nodes, and properties can be added and/or deleted, and property values can be updated. This paper addresses the problem of modeling, storing, and querying temporal property graphs, allowing keeping the history of a graph database. This paper introduces a temporal graph data model, where nodes and relationships contain attributes (properties) timestamped with a validity interval. Graphs in this model can be heterogeneous, that is, relationships may be of different kinds. Associated with the model, a high-level graph query language, denoted T-GQL, is presented, together with a collection of algorithms for computing different kinds of temporal paths in a graph, capturing different temporal path semantics. T-GQL can express queries like “Give me the friends of the friends of Mary, who lived in Brussels at the same time than her, and also give me the periods when this happened”. As a proof-of-concept, a Neo4j-based implementation of the above is also presented, and a client-side interface allows submitting queries in T-GQL to a Neo4j server. Finally, experiments were carried out over synthetic and real-world data sets, with a twofold goal: on the one hand, to show the plausibility of the approach; on the other hand, to analyze the factors that affect performance, like the length of the paths mentioned in the query, and the size of the graph."
- Proyecto final de GradoTemporal graph visualizer(2020-11-17) Orlando, Diego; Ormachea, Joaquín; Vaisman, Alejandro Ariel; Aizemberg, Diego Ariel"Real world scenarios are increasingly being represented with graph databases. Networks in general, and social networks in particular, can be represented as node in a graph, linked through edges. When relationships and node include temporal information, the graphs are called temporal. Temporal graphs are then, graphs that keep track of the history of their nodes and edges. Although these scenarios are normally found in real-world scenarios, there is no tool in the market that can handle appropriately the temporal dimension in graphs. The present work introduces a platform to address this problem. The framework presented here allows displaying temporal graphs and navigating them across time. The result of queries expressed in a high level temporal query language can also be captured and navigated using this tool."