Forensic Science Database


Crime scene Glass Identification Database

1. Sources:

Creator: B. German, Central Research Establishment, Home Office Forensic Science Service, Aldermaston, Reading, Berkshire RG7 4PN

2. Information

3. Attribute Information

1. Id number: 1 to 214
2. RI: refractive index
3. Na: Sodium (unit measurement: weight percent in corresponding oxide, as are attributes 4-10)
4. Mg: Magnesium
5. Al: Aluminum
6. Si: Silicon
7. K: Potassium
8. Ca: Calcium
9. Ba: Barium
10. Fe: Iron
11. Type of glass: (class attribute)

-- 1 building_windows_float_processed
-- 2 building_windows_non_float_processed
-- 3 vehicle_windows_float_processed
-- 4 vehicle_windows_non_float_processed (none in this database)
-- 5 containers
-- 6 tableware
-- 7 headlamps

4. Database:

Glass Database file has 214 instances. The data required for 100% accuracy is:

100 * 10 variables * 7 classes ==> 7,000 (instances)

This severely limited data can only be used to make an educated guess by the DecisionMaker.

Row 67 - 74 will be used for the question file. The Glass Database file has 206 instances. Below are the first 10 instances:

Glass database file (206 instance):

1,1.52101,13.64,4.49,1.10,71.78,0.06,8.75,0.00,0.00,1
2,1.51761,13.89,3.60,1.36,72.73,0.48,7.83,0.00,0.00,1
3,1.51618,13.53,3.55,1.54,72.99,0.39,7.78,0.00,0.00,1
4,1.51766,13.21,3.69,1.29,72.61,0.57,8.22,0.00,0.00,1
5,1.51742,13.27,3.62,1.24,73.08,0.55,8.07,0.00,0.00,1
6,1.51596,12.79,3.61,1.62,72.97,0.64,8.07,0.00,0.26,1
7,1.51743,13.30,3.60,1.14,73.09,0.58,8.17,0.00,0.00,1
8,1.51756,13.15,3.61,1.05,73.24,0.57,8.24,0.00,0.00,1
9,1.51918,14.04,3.58,1.37,72.08,0.56,8.30,0.00,0.00,1
10,1.51755,13.00,3.60,1.36,72.99,0.57,8.40,0.00,0.11,1

Click here to see the glass database file.
 

Case 67 - 74 will be used as a test.

Question                                                                                 Answer

67,1.52152,13.05,3.65,0.87,72.22,0.19,9.85,0.00,0.17,             1
68,1.52152,13.05,3.65,0.87,72.32,0.19,9.85,0.00,0.17,             1
69,1.52152,13.12,3.58,0.90,72.20,0.23,9.82,0.00,0.16,             1
70,1.52300,13.31,3.58,0.82,71.99,0.12,10.17,0.00,0.03,           1
71,1.51574,14.86,3.67,1.74,71.87,0.16,7.36,0.00,0.12,             2
72,1.51848,13.64,3.87,1.27,71.96,0.54,8.32,0.00,0.32,             2
73,1.51593,13.09,3.59,1.52,73.10,0.67,7.83,0.00,0.00,             2
74,1.51631,13.34,3.57,1.57,72.87,0.61,7.89,0.00,0.00,             2

Click here to see the question file.

5. Results.

Click "Average/+ Integer":

=================== Beginning =====================
 
 

1.52152 13.05 3.65 0.87 72.22 0.19 9.85 0 0.17

1

1.52152 13.05 3.65 0.87 72.32 0.19 9.85 0 0.17

1

1.52152 13.12 3.58 0.9 72.2 0.23 9.82 0 0.16

1

1.523 13.31 3.58 0.82 71.99 0.12 10.17 0 0.03

1

1.51574 14.86 3.67 1.74 71.87 0.16 7.36 0 0.12

Can not make a Prediction.
 
 

1.51848 13.64 3.87 1.27 71.96 0.54 8.32 0 0.32

Can not make a Prediction.
 
 

1.51593 13.09 3.59 1.52 73.1 0.67 7.83 0 0

2

1.51631 13.34 3.57 1.57 72.87 0.61 7.89 0 0

2

=================== End ==========================

6. Analysis

6 out of 8 cases have predictions. The predictions are 100% right on these 6 instances. Despite the severe poverty of the data in this case, the DecisionMaker correctly predicted 6 cases and identified the other 2 cases as "Cannot make a prediction". For 10 variables and 7 classes, 208 training instances are not enough.