The life expectancy of people is increasing and related to that is an increase in the elderly population. The idea is to ensure that the elderly stay longer in their homes. A lot of projects work on ways allowing elderly persons to stay at home, these projects has focused to assess how a person copes by continuous monitoring of his/her activities through sensors measurements. The objective of this paper is to design a multimodal software system for managing two services of ambient assistance for elderly and/or disabled person in intelligent habitat health: Symptom Detection Service and Comfort Service. These services use several sensors installed in the home and on the persons, to collect information at any time about location and state of the person, and to ensure his comfort in the home. For helping decision maker choose appropriate assistance for these persons. This multimodal software platform is modeled by Colored Timed and Stochastic Petri nets (CTSPN) simulated in CPNTools.