iTETRIS Platform Architecture for the Integration of Cooperative Traffic and Wireless Simulations

The use of cooperative wireless communications can support driving through dynamic exchange of Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages. Traffic applications based on such systems will be able to generate a safer, faster, cheaper and cleaner way for people and goods to move. In this context, the iTERIS project aims at providing the framework to combine traffic mobility and wireless communication simulations for large scale testing of traffic management solutions based on cooperative systems. This paper addresses the description and explanation of the implementation choices taken to build a modular and interoperable architecture integrating heterogeneous traffic and wireless simulators, and application algorithms supporting traffic management strategies. The functions of an “in-between” control system for managing correct simulation executions over the platform are presented. The inter-block interaction procedures identified to ensure optimum data transfer for simulation efficiency are also introduced

Verifying Real-Time Systems using Explicit-time Description Methods

Timed model checking has been extensively researched in recent years. Many new formalisms with time extensions and tools based on them have been presented. On the other hand, Explicit-Time Description Methods aim to verify real-time systems with general untimed model checkers. Lamport presented an explicit-time description method using a clock-ticking process (Tick) to simulate the passage of time together with a group of global variables for time requirements. This paper proposes a new explicit-time description method with no reliance on global variables. Instead, it uses rendezvous synchronization steps between the Tick process and each system process to simulate time. This new method achieves better modularity and facilitates usage of more complex timing constraints. The two explicit-time description methods are implemented in DIVINE, a well-known distributed-memory model checker. Preliminary experiment results show that our new method, with better modularity, is comparable to Lamport's method with respect to time and memory efficiency

Implementation and evaluation of the sensornet protocol for Contiki

Sensornet Protocol (SP) is a link abstraction layer between the network layer and the link layer for sensor networks. SP was proposed as the core of a future-oriented sensor node architecture that allows flexible and optimized combination between multiple coexisting protocols. This thesis implements the SP sensornet protocol on the Contiki operating system in order to: evaluate the effectiveness of the original SP services; explore further requirements and implementation trade-offs uncovered by the original proposal. We analyze the original SP design and the TinyOS implementation of SP to design the Contiki port. We implement the data sending and receiving part of SP using Contiki processes, and the neighbor management part as a group of global routines. The evaluation consists of a single-hop traffic throughput test and a multihop convergecast test. Both tests are conducted using both simulation and experimentation. We conclude from the evaluation results that SP's link-level abstraction effectively improves modularity in protocol construction without sacrificing performance, and our SP implementation on Contiki lays a good foundation for future protocol innovations in wireless sensor networks