  Robertson's 2-poisson information retrieve model does not use location and
category information. We constructed a framework using location and category
information in a 2-poisson model. We submitted two systems based on this
framework to the IREX contest, Japanese language information retrieval contest
held in Japan in 1999. For precision in the A-judgement measure they scored
0.4926 and 0.4827, the highest values among the 15 teams and 22 systems that
participated in the IREX contest. We describe our systems and the comparative
experiments done when various parameters were changed. These experiments
confirmed the effectiveness of using location and category information.
