Demo Examples

Case study We present the graph-based model through a case study that may occur during a Crisi Mmanagement Sitution-like activity.

CMS architecture
CMS architecture
  1. General description of the case study

For CMS-like activities, cooperation is based on information exchanges between mobile participants collaborating for the achievement of a common mission. This information consists in different kinds of data, including observation data and analysis data, that can be produced periodically or immediately after a particular event.

These data are supported by different kinds of media, namely text, audio, video and any combination between themselves. Such media are supported by different codec such as H263 or MPEG4, inducing different QoS requirements on the end-to-end data transport. QoS requirements may be expressed in terms of minimal bandwidth, error sensitivity, intra/inter media synchronization constraints. They may also deal with temporal constraints depending on the required interactivity between participants.

CMS participants carry mobile or fixed devices and interact using wired or wireless communications. Depending on their role in the mission, each participant provides a set of services. Services to be performed are dynamically assigned to the participants according to the evolution of the mission, considering their skills and their location.

A CMS team may thus be constituted of participants having different roles, for instance: a controller of the mission, several coordinators, and several teams of field investigators, each one being supervised by a coordinator. Each participant has to perform different functions:

  • controllerís functions include supervising and authorizing actions to be done by coordinators and investigators;
  • in relationship with the controller and the other coordinators, a coordinator has to manage his/her investigators including their tasks assignment. It also has to collect, interpret, summarize and diffuse information from and towards his investigators;
  • investigatorsí functions include exploring the operational field, observing, analyzing, and reporting about of the situation. Investigators also act for helping, saving and repairing.
  1. Scenario description

We assume a CMS team composed of a fixed controller, say C, and two investigators, say A and B, moving within the exploration field. For simplifying the model explanation, controller and coordinator roles are merged into a unique role: controller.

Functions performed by investigators include Observing the exploration field and Reporting feedbacks to the controller. Two kinds of feedbacks are distinguished:

  • feedbacks D are Descriptive data; they are transmitted by means of audio/video (a,v);
  • feedbacks P are Produced data; they express the analysis of the situation by an investigator. They are transmitted by means of audio (a).

The controllerís function includes Supervising the whole mission, i.e. deciding actions to be performed from the analysis of the observation feedbacks D transmitted by investigators. For taking decision, the controller may also use the produced feedback P transmitted by the investigators. Finally, each participant is supposed to carry a single mobile machine provided with wireless communication capacities.

The scenario is divided into two successive steps.

Step 1. The first step is the investigation step:

  • investigators A and B provide continuous feedbacks D to the controller C; they also provide periodical feedbacks P;
  • there is no priority difference between communications A-C and B-C, but transmissions of feedbacks D are more important than those of feedbacks P.
investigation step
Figure 10: Case study: investigation step

The first step ends when a critical situation is discovered by an investigator, say A for instance.

Step 2. The second step is the action step:

  • having discovered a critical situation, A conserves the same functions (O, R) as in the exploration step but provides feedbacks D to both controller C and investigator B. A also provides feedbacks P to C;
  • B reports now only feedback P to controller C on the basis of the feedback D transmitted by investigator A;
  • due to the criticism of the situation reported by A, communication A-C is more important than A-B and B-C. Moreover, exchanges of feedbacks D between A and C are of the highest importance; feedbacks P between A and C are of a medium importance; feedbacks D between A and B, and feedback P between B and C are of the lowest importance.
action step
Figure 11: Case study: action step

Input Graph: #0#{{1,0,0},{2,0,0},{3,0,0}}#{{-1,1,-1},{-1,-1,-1},{-1,1,-1}}#$

Graph rule: #1#{{{var,m0,const,0,const,0},{const,2,const,0,const,0}};{};{};{{const,n2,const,0,const,0}}}

            #{{-1,1,-1},{-1,-1,-1},{-1,2,-1}}#$

Output Graph: #0(1)#{{1,0,0},{2,0,0},{3,0,0},{n2,0,0}}#{{-1,1,-1,-1},{-1,-1,-1,-1},{-1,1,-1,-1},{-1,2,-1,-1}}#$