2. POLICY HIERARCHIES
The generic characteristics of a disaster management
policy can represented as an object. A number of
operations can be performed on it. The main motivation
for understanding hierarchical relationships between
policies is to determine what is required for the
satisfaction of policies. The general concept of policy
hierarchies was discussed in reference (Moffett and
Sloman, 1991). If a high-level policy is defined or
changed, it should be possible to decide what lower-
level policies must be created or changed. Another one
is for analysis to see whether the set of lower-level
policies actually fulfill the higher-level policy, by
providing complete cover over all the target objects and
actually meeting the policy goals. Therefore, there is a
need to be able to formally describe the relationships
between high-level policies, refined lower-level
policies, and the mechanisms, actions, and procedures
which finally implement them. These policy hierarchies
need to be constructed in such a way that a human
manager of management system of environmental
disaster can determine whether the policies for
environmental disaster management are being satisfied.
2.1 Attributes
The attributes of the policy can be shown in Fig 1.
These attributes can be given as the followings.
| Management Action Policy |
|
| | | 2]
| Modality | |. Subjeas d [Objects] | Constrains |
Fig 1 Management Action Policy Attributes
(D)Modality policies: They can be divided into two
different classes of policies.
(a)Imperative policies: An agent has the imperative
power to carry out an action.
(b)Authority policies: An agent has the legitimate
power to carry out an action.
(2)Policy subjects: They are the entities to whom the
policy is directed.
(3)Policy target objects: They are the objects at which
the policy is directed.
(4)Policy objectives: They are expressed as a pair of
goals and target objects. The policy goal defines
either a high-level goal or a procedure. Procedures
are a defined sequence of actions.
(5)Policy constraints: They are a set of predicates which
constrain the applicability of the policy. They may be
774
related to terms of general disaster properties, such
as unavailability, duration, weight and some other
conditions.
2.2 Hierarchy
In environment disaster management, a high-level
policy may be used as the basis from which multiple
lower-level policies are derived. Various methods for
refining the goals, partitioning the targets can be used
for the derivation. These methods can be discussed as
the followings.
(1)Partitioning targets: while the goal is the same, the
target set of the lower-level policy may be a subset of
the target set of the higher-level one. In order to
ensure that the partitioning is complete, the whole
target must be covered by lower-level policies.
(2)Refining goal: The goal of a high-level may be
refined into one or more lower-level goals, referring
to the same target.
(3)Procedures: A policy may be refined by an unordered
set of lower-level ones.
2.3 Action
There is a close relationship between making policies
in a policy hierarchy and giving responsibility for a
task. The subject of a policy can be viewed as the entity
responsible for currying out the goals or actions defined
by the policy. Thus, the specification of management
responsibility can be modeled using the policy objects.
When a manager of environmental disaster
management system is assigned with responsibility for
an objective, there is a need for an imperative policy to
motivate the manager the power to perform the action.
There are three different kinds of policy as the
followings.
(1)Action responsibility: It represents the sense of being
“ responsible for ” an objective.
(2)Reporting responsibility: It can be achieved by the
agent reporting to the manager on completion or at
regular intervals.
(3)Monitoring responsibility: There are two kinds of
monitoring responsibility for environmental disaster
management. Subject monitoring is related to an
action responsibility, where the action subject is the
target of a monitoring policy. Target monitoring
occurs when targets of the action and monitoring
policy are the same.
The accepting responsibility related to environmental
disaster management ensures that a policy subject
accepts responsibility. There are two different kinds of
accepting responsibility as the followings.
(1)Imperatives for automated managers: As soon as
automated managers are made aware of a policy,
they will begin to perform the actions required to
satisfy the policy.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7. Budapest, 1998
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