The demo.m is from the following paper:

Anti-Drift in E-nose: A Subspace Projection Approach with Drift Reduction

This paper can be download from 

1. for DRCA, the DRCA.m is used
2. data1.mat £­£­the data includes three subsets:master data collected 5 years ago is used as source domain data (no drift). The slave 1 and slave 2 data collected now are used as target domain data (with drift and shift).the sensor calibration between slaves and master is made by using linear regression.
3. data2.mat £­£­the data includes three subsets:master data collected 5 years ago is used as source domain data (no drift). The slave 1 and slave 2 data collected now are used as target domain data (with drift).The sensor calibration step is omitted.

rows of each subset are:
Column 1, Column 2, Column 3, Column 4, Column 5, Column 6, Column 7

Empty,   category,  humidity,  temperature, sensor1, sensor2, sensor3, sensor4
   
wherein sensor1 to sensor4 are gas sensors TGS2620, TGS2602, TGS2201a, TGS2201b, respectively

Categories are formaldehyde, benzene, toluene, carbon monoxide, nitrogen dioxide, ammonia, respectively.