refactor data structure
refactor data structure

MLR-au/pdsc-olac-visualisation,MLR-au/olac-visualisation,MLR-au/pdsc-olac-visualisation,MLR-au/olac-visualisation,MLR-au/pdsc-olac-visualisation,MLR-au/olac-visualisation,MLR-au/olac-visualisation,MLR-au/pdsc-olac-visualisation