#505
Anomaly Detection
Find unusual transactions: huge amounts, odd hours, bursts and new merchants - with the reason.
Technique: Robust z-score (median / MAD), hour-of-day rarity, velocity window, rolling 3-sigma band
Read the code:
src/main/java/com/study/advlab/anomaly/AnomalyDetector.javasrc/main/java/com/study/advlab/anomaly/AnomalyService.java
Payments checked
2,168
last 90 days
Flagged
30
176,574 THB in total
Confirmed fraud
0
after a person checked
False alarms
0
use them to tune the threshold
Every payment red = flagged · log scale
Flagged payments
| Payment | Amount | Why | Score | Review |
|---|---|---|---|---|
| ACC-1021 · Luxury Watch Boutique
Jewellery · 15 Sep 14:09 |
4,999.27 | • Amount 22.8x the usual (z = 11.7)• First ever payment in "Jewellery" | 3.94 | |
| ACC-1009 · Luxury Watch Boutique
Jewellery · 15 Oct 14:09 |
29,553.06 | • Amount 29.9x the usual (z = 10.1)• First ever payment in "Jewellery" | 3.49 | |
| ACC-1005 · Luxury Watch Boutique
Jewellery · 12 Oct 14:09 |
15,487.61 | • Amount 23.1x the usual (z = 9.2)• First ever payment in "Jewellery" | 3.23 | |
| ACC-1025 · Luxury Watch Boutique
Jewellery · 20 Aug 14:09 |
29,296.07 | • Amount 25.9x the usual (z = 8.3)• First ever payment in "Jewellery" | 2.98 | |
| ACC-1013 · Luxury Watch Boutique
Jewellery · 17 Sep 14:09 |
5,223.00 | • Amount 31.1x the usual (z = 7.8)• First ever payment in "Jewellery" | 2.84 | |
| ACC-1029 · Luxury Watch Boutique
Jewellery · 21 Sep 14:09 |
15,817.97 | • Amount 17.8x the usual (z = 7.6)• First ever payment in "Jewellery" | 2.77 | |
| ACC-1001 · Luxury Watch Boutique
Jewellery · 18 Oct 14:09 |
3,329.47 | • Amount 15.5x the usual (z = 7.6)• First ever payment in "Jewellery" | 2.76 | |
| ACC-1007 · Online Casino Top-up
Gaming · 26 Aug 03:13 |
4,335.85 | • Amount 4.4x the usual (z = 4.6)• Night-time payment (03:13)• First ever payment in "Gaming" | 2.70 | |
| ACC-1022 · Online Casino Top-up
Gaming · 19 Aug 03:10 |
1,716.89 | • Amount 3.9x the usual (z = 4.3)• Night-time payment (03:10)• First ever payment in "Gaming" | 2.64 | |
| ACC-1012 · Online Casino Top-up
Gaming · 09 Aug 03:17 |
6,399.32 | • Amount 3.8x the usual (z = 4.0)• Night-time payment (03:17)• First ever payment in "Gaming" | 2.55 | |
| ACC-1017 · Luxury Watch Boutique
Jewellery · 06 Sep 14:09 |
34,895.13 | • Amount 14.7x the usual (z = 6.8)• First ever payment in "Jewellery" | 2.55 | |
| ACC-1002 · Online Casino Top-up
Gaming · 16 Sep 03:03 |
6,002.12 | • Amount 3.8x the usual (z = 3.7)• Night-time payment (03:03)• First ever payment in "Gaming" | 2.45 | |
| ACC-1027 · Online Casino Top-up
Gaming · 22 Aug 03:31 |
1,723.47 | • Night-time payment (03:31)• First ever payment in "Gaming" | 2.33 | |
| ACC-1017 · Online Casino Top-up
Gaming · 01 Oct 03:38 |
7,754.47 | • Night-time payment (03:38)• First ever payment in "Gaming" | 2.26 | |
| ACC-1010 · Gift Card Hub
Gift cards · 15 Sep 23:14 |
398.14 | • 5 payments within 10 minutes | 1.10 | |
| ACC-1010 · Gift Card Hub
Gift cards · 15 Sep 23:14 |
398.14 | • 5 payments within 10 minutes | 1.10 | |
| ACC-1010 · Gift Card Hub
Gift cards · 15 Sep 23:12 |
398.14 | • 5 payments within 10 minutes | 1.10 | |
| ACC-1010 · Gift Card Hub
Gift cards · 15 Sep 23:11 |
398.14 | • 5 payments within 10 minutes | 1.10 | |
| ACC-1010 · Gift Card Hub
Gift cards · 15 Sep 23:11 |
398.14 | • 5 payments within 10 minutes | 1.10 | |
| ACC-1021 · Tops Market
Grocery · 28 Sep 19:36 |
595.82 | • Amount 2.7x the usual (z = 3.7) | 1.07 | |
| ACC-1024 · Gift Card Hub
Gift cards · 23 Sep 23:15 |
972.79 | • 5 payments within 10 minutes | 1.05 | |
| ACC-1024 · Gift Card Hub
Gift cards · 23 Sep 23:13 |
972.79 | • 5 payments within 10 minutes | 1.05 | |
| ACC-1024 · Gift Card Hub
Gift cards · 23 Sep 23:13 |
972.79 | • 5 payments within 10 minutes | 1.05 | |
| ACC-1024 · Gift Card Hub
Gift cards · 23 Sep 23:11 |
972.79 | • 5 payments within 10 minutes | 1.05 | |
| ACC-1024 · Gift Card Hub
Gift cards · 23 Sep 23:10 |
972.79 | • 5 payments within 10 minutes | 1.05 | |
| ACC-1003 · Gift Card Hub
Gift cards · 23 Oct 23:15 |
518.04 | • 5 payments within 10 minutes | 1.03 | |
| ACC-1003 · Gift Card Hub
Gift cards · 23 Oct 23:14 |
518.04 | • 5 payments within 10 minutes | 1.03 | |
| ACC-1003 · Gift Card Hub
Gift cards · 23 Oct 23:13 |
518.04 | • 5 payments within 10 minutes | 1.03 | |
| ACC-1003 · Gift Card Hub
Gift cards · 23 Oct 23:11 |
518.04 | • 5 payments within 10 minutes | 1.03 | |
| ACC-1003 · Gift Card Hub
Gift cards · 23 Oct 23:10 |
518.04 | • 5 payments within 10 minutes | 1.03 |
Daily total with a rolling 3-sigma band outside the band = unusual day