Since many instances of a particular MO class may
exist, and each instance must be accessible and
uniquely distinguishable, names must be assigned to all
instantiated objects. A hierarchical naming structure
has been chosen for rural land use monitoring naming,
The naming structure and events associated with an
rural land MO will be inherited by these specialized
subclasses. The inheritance is primarily a syntactic
mechanism as one could simply include the definitions
of the superclass in the subclass MO definitions to
accomplish the same effect. An MO defining a class of
rural land objects is depicted in Fig. 1. Ellipsoidal
shapes describe data attributes. Rectangular shapes
describe operations to test and use an rural land. Events
are described by triangular shapes.
Uptime x
Name Rural Land
Fig. 1 Example of an MO
4. MONITORING MODEL
There are a number of fundamental problems
associated with monitoring of rural land use. For
example, rural land quality means its ability that it can
be used to provide agricultural products in normal
status. However, it is very difficult to obtain a global,
consistent view of rural land components related to
rural land quality in a rural land system through
collecting event reports. Because estimation errors of
real time quality, use and other variables in the
reporting of events may result in these events being
processed in the incorrect methods. Another problem is
that the monitoring system may itself compete for
limited resources with the rural land use system being
observed and so modify its behavior. To solve these
problems, the monitoring system must provide a set of
general functions for generating, processing,
disseminating, and presenting monitoring information.
A good monitoring model is a framework for design
and implementation of the monitoring system for rural
land use. This model is used to determine the facilities
needed to design and construct the system. Some
important problems related to the model
implementation include its concepts, terminology, and
monitoring means. The object modeling technique
(Rumbaugh, 1991) can be widely used for design and
implementation of monitoring the model.
4.1 Service and Functions
The generic monitoring services built on the model are
important tools for implementing the monitoring
system and for debugging during the system
development. On the other hand, monitoring services
are also essential for process control and management
automation in the monitoring system. Thus, such
monitoring model is based on a set of monitoring
functions and may be used as a practical framework for
the implementation of an advanced rural land
management system. The main functions of
monitoring model can be described as the followings.
(1)Generation of monitored information, including
status, event and trace reports.
(2)Processing of monitored information, including to
validate, combine and filter relevant information.
(3)Dissemination of required information to relevant
objects who have subscribed to the service.
(4)Presentation of monitored information to human
users via flexible graphical facilities.
4.2 Techniques and Tasks
In the model, a managed object in the monitoring
system is defined as any rural land, the monitoring
system hardware or software component whose
behavior can be controlled by the monitoring system.
The object encapsulates its behavior behind an
interface, which hides the internal details that are vital
for monitoring purposes. Monitoring can be performed
on an object or a group of related objects. The behavior
of an object can be defined and observed in terms of its
status and events. Two kinds of monitoring techniques,
time-driven monitoring and event-driven monitoring,
are used respectively for acquiring periodic status
information and information about the occurrence of
events of interest. Further, the monitoring model
performs the following four monitoring tasks.
(l)Generation: when some important events are
detected, the related event and status reports are
generated. These monitoring reports are used to
construct monitoring traces, which represent
current and historical views of activity of rural land
use.
(2)Processing; it converts the raw monitoring data to
the required format.
(3)Dissemination: the monitoring reports are
disseminated to the appropriate users, managers and
processing agents.
(4)Presentation: gathered, processed, and formatted
information is displayed to users.
4.3 Systems and Monitors
Various detection mechanisms can be used to identify
the occurrence of events. According to which
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