Akira Asano

Study on Formal Specification of Automatic Train Protection and Block System for Local Line

This paper presents a formal specification of an Automatic Train Protection and Block (ATPB) model for local line railway system in Japan proposed by the author [12], and validates the model by internal consistency proving and systematic testing. The system consists of two parts, the on-board subsystem and ground subsystem. The former is to detect the basic state of train, such as position, speed and integrity, monitor the speed, communicate with ground equipment and record the relative events. And the latter is responsible for communicating with train, controlling the route and interlocking, and decision-making for train operation adjustment. The main purpose of this project is to improve the efficiency and guarantee that there is no collision, no derailment and no over speeding at the same. The formal language used in this project is VDM++. And the state and specification of operation are all checked and validated using VDMTools. The results confirm the correctness of this system and the model throws new light on practical system design.

Formal verification of Communication based Train Control system

In the CBTC (Communication-based Train Control) system, the wireless terminals (repeaters) are the communication bridges between the control-center and the on-board system. This paper presents a formal analysis of the train-to-ground communication link verification (TCLV) system. Firstly, this paper lists the requirements and analyzes the necessary system state and operations, then transforms the natural language describing system into a rigorous mathematical described model. At last, for the formal model, the proof obligations are proved to verify its internal consistency, and the validations are proved to verify the states and operations satisfying the expected requirements. The result of proof denotes that the actual system designed as the specification described in this paper would satisfy the requirements under the premise of safety and reliability.