Individual Travel Knowledge Graph-Based Public Transport Commuter Identification: A Mixed Data Learning Approach

Table 1

Valid fields of multisource PT data.

	Bus	Metro
Smart card transaction data	User card code	User card code
	Boarding/alighting line number	Inbound/outbound line number
	Boarding/alighting station number	Entry/exit station code
	Boarding/alighting time	Inbound/outbound time
GPS data	Line number	—
	Data return time
	Latitude and longitude of return point
Network and station data	Arc start/end number	Entry/exit station code
	Arc length	Inbound/outbound name
	Longitude and latitude of stations	Longitude and latitude of stations
	Station spacing	Station spacing

Note: the card codes of the smart card data are not always identical to the individuals. For example, a smart card can be shared among family members and friends, or a traveler can hold several cards. However, such usage may not be the majority, especially when registered monthly passes belong to the smart cards [9]. With the rapid development of mobile payment, the PT systems apply to the quick response (QR) code payment besides the traditional smart card payment in Beijing. However, the code rules of QR codes are not consistent with those of the smart cards, and the service operators do not provide the number of QR codes in the transaction application software. Therefore, it is infeasible to associate the individual travel data and QR code transaction data that account for about 20% of all transaction data in Beijing. Thus, this study focuses on the smart card transaction data to effectively introduce and match the corresponding individual travel survey data. What is more, smart card data are ticket-dependent methods, and they typically underestimate the travel demand owing to possible fare evaders in many worldwide transit systems [26]. However, no ticketing system can avoid fare evasion, and the percentage of possible fare evaders is relatively low, so this limitation is ignored in the study. The PT operating companies allowed the use of the smart card data only for research purposes; the individual information had been anonymized prior to the analysis to protect the privacy of cardholders throughout this study.