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This page only presents some of the projects I work on.

Sample CPS

It is always useful to start with a simple example that exhibits the properties that we want to focus on. On this airbag video:

it is possible to see two airbags: one that inflates at the right time and another that deploys late. This represents the character of a Cyber-Physical System that needs to execute the steps correctly (infate the airbag) and execute them at the proper time in sync with the physical process (the driver traveling towards the steering wheel in a crash).

Below are some of the projects we work on.

Zero-Slack Scheduling

Zero-Slack Scheduling is a scheduling framework for real-time mixed-criticality systems. Specifically, it targets systems where the utilization-based scheduling priorities are not aligned with the criticality of the tasks. With this framework we implemented a family of schedulers, resource allocation protocols, and synchronization protocols to support the scheduling of mixed-criticality systems.

Mixed-Criticality Scheduling and Safety Standards

Safety standards like the DO-178B for avionics and the ISO 26262 in automotive include safety levels that map to criticality levels. For a discussion of the use of Mixed-Criticality scheduling in automotive systems with AutoSAR and ISO 26262 please look at the paper: Applying the AUTOSAR timing protection to build safe and efficient ISO 26262 mixed-criticality systems

Zero-Slack QRAM

Zero-Slack Q-RAM combines ZS-RM and Q-RAM to enable overbooking (cycles allocated to more than one task) not only between tasks of different criticality but also to task with different utility to the mission of the system.

We implemented three version of the ZS-QRAM scheduler: a modification to the Linux/RK kernel (and kernel module), an independent kernel module implementation, and a daemon-based implementation.

We developed a number of experiments to showcase the effects of the scheduler in a drone mission. In particular, first we demonstrate how the wrong scheduling can actually crash a drone. This is shown in this video.

Secondly, we showcase how in a full mission ZS-QRAM not only preserve the saftey of the flight but also maximizes the utility of the mission. In particular, the demo shows a surveillance mission where a video-streaming task and an object recognition tasks are dynamically adjusted according to their utility to the mission. This video shows this case.

Download Scheduler Implementations

To access both the kernel and kernel module implementations, please go to our Drone RK site.

Multiple variations of the ZSRM/ZSQRAM scheduler and analysis tools had been developed. Some of these implementation can be accessed by selecting the appropriate tab below.

A library implementation for VxWorks can be downloaded from the ECE WISE Lab website.

To access the software click here.