Community Computing - Advanced Design Approaches to Emerging Software Systems - page 200

services need to be dynamically provided accord-
ing to users' requests, while others, such as public
security services, should be offered continuously.
Besides, some urgent services have to be executed
even though those services are unpredictable or not
prepared. According to the difference of services'
style, we distinguished levels of communities as
follows: static, dynamic, and evolving community.
According to the style of necessary services, we
can decide the level of a community to create.

initiation to termination and one optional stage,
deactivation.

1. Initiation: If a member involved in a
society, called a society member, or com-
munity recognizes a community goal, it is
able to request an initiation of a community
instance from a society manager, an agent to
oversee a whole society, (See section about
computational models regarding society
managers and community managers.) The
society manager then creates a community
manager, and the community manager per-
forms member discovery based on members'
condition. The community manager is able to
decide the suitability of each member using
the member-role binding condition described
in the community type. After all members
are selected, the community manager makes
sure that all members are aware of their goal
and cooperation process. If all members
provide confirmation, an initiation stage is
complete.
2. Activation: Most communities are acti-
vated as soon as they are initiated, which
means that members start their cooperation
process to achieve the community's goal.
In the case of a static community, once a
community is activated, it may be deacti-
vated rather than terminated, because static
communities typically need to exist all the
time. If the deactivated community instance
is reactivated, members restart or continue
their cooperation according to previously
established protocols.
3. Deactivation (optional): After a community
instance is created, sometimes it is required
that the cooperation process stops for a while.
In this situation, the community instance is
deactivated. When a community instance is
deactivated, its community manager stores
the information about an instance, including
community members and the status of the

1. Static community: It is the simplest com-
munity. In this community, all members and
their cooperation are predefined, so static
communities are used to provide permanent
services without replacing providers, such
as a community of temperature sensors or
a community of ambulances in a city.
2. Dynamic community: It dynamically
decides its members and their cooperation,
while its roles and goals are predefined like
static communities. For example, a dynamic
community which consists of nearby neigh-
bors, policemen, and image sensors, can be
used to help a community in finding a lost
child. To find the child effectively, the clos-
est member to the child should be selected
in execution time and then cooperate with
other members in the most efficient way
possible.
3. Evolving community: It is capable of be-
ing built on demand. When a goal arises,
the necessary roles and cooperation among
roles are designed dynamically at request
time and then operated. In urgent cases, an
evolving community's services would be
useful, since the evolving community can
solve the emergent problems even though
a system does not prepare such services at
request time.

In our community computing, each community
has a life cycle from initiation to termination.
The community's life cycle has three stages from