Home Page of XESTT

A Unified Employee Scheduling Data Format

This site is under construction, and will be for some time yet. If you are interested and can't wait, please contact me (Jeff Kingston) by email.

XESTT is an XML data format for defining instances and solutions of employee scheduling problems. It is based on XHSTT, which has become the standard format for expressing instances and solutions of high school timetabling problems. Indeed, it is the same as XHSTT except for some extensions.

Although the term used here is `employee scheduling', for the foreseeable future the project will be limited to nurse rostering.

For an overview of this project, including a technical exposition of how instances in other formats are mapped into XESTT, read this draft paper. For an in-depth discussion of modelling history, read this draft paper. For more on XHSTT, consult the home page of Gerhard Post. For a technical specification of both XHSTT and XESTT, consult the specification pages of the HSEval timetable evaluator.

The XESTT project is led by Jeff Kingston.

The First International Nurse Rostering Competition

You can find all the instances from the First International Nurse Rostering Competition , converted into GZipped XESTT archive files, in this directory. An XESTT archive file contains any number of instances and any number of sets of solutions. Each of these archive files contains one set of instances from the competition. You can download all of these archive files at once, as a GZipped tar file, by clicking here. These are working versions and will probably change before this project is completed.

The Second International Nurse Rostering Competition

You can find all the instances from the Second International Nurse Rostering Competition, converted into XESTT archive files, in this directory (I haven't done these yet). These instances have to make a stab at what is wanted to express the long-term constraints. If you don't like how they do it, please let me know. Or you could grab the nrconv converter (see below) and modify it to do it your way.

Other Instances

It is my intention to convert instances in one or two other formats before taking a break. If you have an opinion about what those other formats should be, please let me know. I will be looking at the recent Curtois and Qu instances.

The nrconv converter

This is my program for converting nurse rostering instances and solutions from (potentially) any format to XESTT. It is an ANSI C program stored in a gzipped tar file in this directory. Just grab the version with the most recent date.