This paper presents an ecosystem for personal knowledge graphs (PKGs), commonly defined as resources of structured information about entities related to an individual, their attributes, and the relations between them. PKGs are a key enabler of secure and sophisticated personal data management and personalized services. However, there are challenges that need to be addressed before PKGs can achieve widespread adoption. One of the fundamental challenges is the very definition of what constitutes a PKG, as there are multiple interpretations of the term. We propose our own definition of a PKG, emphasizing the aspects of (1) data ownership by a single individual and (2) the delivery of personalized services as the primary purpose. We further argue that a holistic view of PKGs is needed to unlock their full potential, and propose a unified framework for PKGs, where the PKG is a part of a larger ecosystem with clear interfaces towards data services and data sources. A comprehensive survey and synthesis of existing work is conducted, with a mapping of the surveyed work into the proposed unified ecosystem. Finally, we identify open challenges and research opportunities for the ecosystem as a whole, as well as for the specific aspects of PKGs, which include population, representation and management, and utilization.

翻译：本文提出了个人知识图谱（PKGs）的生态系统框架。个人知识图谱通常被定义为关于个体相关实体、实体属性及其关系的结构化信息资源。PKGs是实现安全、复杂个人数据管理与个性化服务的关键支撑技术。然而，在PKGs获得广泛采纳之前，仍存在若干亟待解决的挑战。其中一个基础性挑战在于PKG本身的定义——该术语存在多种解读。我们提出PKG的定义，强调以下两个核心维度：（1）数据由单一主体所有；（2）提供个性化服务为首要目的。我们进一步论证，要充分释放PKG的潜力，需要采用全局视角，并提出PKG统一框架：将PKG定位为更大生态系统中的组成部分，与数据服务和数据源之间建立清晰的接口。本文对现有研究进行了系统性综述与综合，并将已有工作映射至所提出的统一生态系统中。最后，我们识别了该生态系统整体层面以及PKG具体方面（包括构建、表示与管理、应用）的开放挑战与研究机遇。