A Survey on Personal Data Cloud

Table 1

Multidimensional classification of personal data.

Dimension	Categories	Examples	References
Format	(1) Document	DOC, PPT, spreadsheets, and so forth	[3–5, 9, 10, 12, 13, 18]
	(2) Multimedia	Images, videos, audio, and so forth
	(3) Web page and fragment	Search keywords, visited links, cookies, and so forth
	(4) Email	Gmail, Yahoo! Mail, and so forth
	(5) Database	Business data stored in domain-specific services, such as orders, calendars, wish lists, and so forth
Source	(1) Personal devices	PC, smart phones, mobile devices, tablet, and so forth	[5–8, 14, 19–22]
	(2) Services	Web applications, and so forth
	(3) Social network	Facebook, Twitter, blogs, and so forth
	(4) Sensors	GPS, thermometer, wearable devices, and so forth
	(5) The person himself	Email, work schedule, documents, pictures, video, audio
Abstraction level	(1) Metadata	The descriptions of personal data	[11, 14–17]
	(2) Instance data	The contents (instances) of the metadata
Semantics and functions	(1) Preference data	Preferences on books, music, cities, friends, wish list, and so forth	[19, 23–32]
	(2) Communication record	SMS text, phone records, address book, and so forth
	(3) Web footprints	Visited websites, search keywords, social comment logs and social graph, and so forth
	(4) Personal profile	Height, weight, published papers, education/career experiences, exam performance, and so forth
	(5) Consumption service record	Bank account and transaction records, flight and hotel orders, car rental orders, supermarket records, e-commerce transaction record, and so forth
	(6) Public service record	Personal salary records, household energy record, personal credit, and so forth
Storage location	(1) Local/desktop storage	Files located on personal computers and devices	[20, 33–36]
	(2) Distributed cloud storage	Data stored in the cloud of a service
	(3) Centralized cloud storage	Many personal data centralized stored in a public cloud