1. Dynamic Scheduling with the GBT
Results from the Beta Test:
Efficiencies

2. Simulation Results
All Open Sessions for 2006
DSS
Traditional

3. Beta Test: 08B
Based on hours scheduled. Middle number is hours scheduled within this frequency range.
Stringency calculation for high frequencies (K, Ka, and Q-band):
(Based on data with Frequencies: 25, 30, 35, 40, 45 GHz at El=50 deg)
Trimester Stringency Percent Hours A B C

4. Frequency Distribution
Windowed (431 hr/ 15%)
Open (1240 hr/ 44%)
Note: there is more fixed and less windowed than expected, probably because we executed some windowed sessions as fixed for convenience.
Fixed (589 hr/ 21%)
Maintenance (576 hr/ 20%)

5. RA Distribution
The total available time (white) is not representative of demand since there are many B grade hours that have been included. Also, some of the large projects like 8C10 were included. The total executed time (green) is typical with more time near the Galactic Center (17-18 hrs) and near Virgo (12 hrs).

6. Frequency versus Time
Note: the “08” corresponds to the year not the day.

7. Effective Hours
White histogram corresponds to the total available hours scheduled for each band, while the green histogram corresponds to the total “effective” hours for each band.
Trimester 8B should have 2928 hours (although we started a day or so late and ended maybe one day early). We executed hours of Maintenance (not show in plot).

8. Observing Efficiency Blue crosses: TP that were scheduled
Red circles with error bar: “mean” observing efficiency of TP’s within a give frequency bin
Solid curve: minimum observing efficiency. The limit is the solid curve – 0.1

9. Observing Efficiency (Types)
Same as previous plot except we have added additional symbols for TP’s that are below are minimum observing efficiency (curve – 0.1)
Green circles: windowed TP’s
Red triangles: fixed TP’s
Blue squares: open TP’s where more than half of the time was spend below the minimum HA limit. None of these cases had the ignore HA limit flag set!
Open
HA limit
Windowed
Fixed

10. Observing Efficiency (Open)
Only Open TP’s are included.

11. Observing Efficiency (Filtered)
Only open TP’s included with a filter that removed all TP’s that were beyond the HA limit for more than half of the time. We suspect these were manually scheduled.
Ku-band projects: a total of 50 hours; it seems that these were scheduled with low observing efficiencies.
Nissim Kanekar: 8B43, 8B18J
Jeff Mangum: 7A15, 8A21
Jeff Wagg: 8B11

12. Scheduling Issues Observing Efficiency Receiver Availability
Windowed Sessions
Scheduling and Weather
Types: astronomy; commissioning; maintenance
Fixed Sessions
VLBI
Receiver Availability
Overhead Time
Exceptions to the System
Observing Efficiency: restricted sessions will reduce overall observing efficiency. Low frequency sessions (<1 GHz) may be executed under very good weather conditions. This frustrates observers and schedulers.
Windowed Sessions: the window length can extend beyond the weather forecast (few days). What metrics do we use to decide when to schedule a windowed sessions? Currently we just give the windowed session a constant factor increase. Also we may need sub-types (e.g., astronomy, commissioning, maintenance).
VLBI Observations: large projects exist using VLBI and the GBT at high frequency (e.g., megamaser project). How do we incorporate VLBI into the DSS. Is there any reasonable way to do this?
Receiver Availability: since fixed and windowed sessions are restricted and not all receivers are always available the flexibility in the schedule is reduced. How do we determine receiver changes? How do we optimize observing efficiency?
Overhead Time: time spent changing receivers; pointing; calibration. This occurs when changing projects with different receivers. We loose time and therefore we are decreasing the efficiency of the GBT. This is not included into the DSS.
Exceptions to the System: these may be dealt with automatically or manually
Solar system objects (center sky position moves)
Desired minimum duration versus acceptable minimum duration
Horizon to horizon observing
Specifying LST ranges instead of using HA limits
Schedule tied to the phase of a source (e.g., binary phase)

13. Questions?