object types and the class/subclass relationships 
between the types. 
The behavioral component describes the dynamics of 
alarm correlation. [t contains three major components: 
the message class hierarchy, the correlation class 
hierarchy, and correlation rules. The managed object 
classes, message classes, correlation classes, and 
correlation rules are organized into hierarchies. These 
hierarchies are related by “producer/consumer” 
dependencies. Managed objects are producers of alarm 
messages, messages produce correlation, and rules are 
consumers of all the above components. 
Managed classes describe rural lands and rural land 
system equipment types. Managed objects are 
organized into a hierarchy using class/subclass 
relations. The root of the hierarchy contains the most 
general information common to all managed objects. 
The next level of the hierarchy describes the basic 
managed object classes. Each subclass inherits 
parameters, values, and attributes. The managed object 
hierarchy is an abstraction of physical managed objects. 
The hierarchy is specific to an application. 
Configuration model. The configuration model of the 
monitoring system is constructed from the instances of 
individual managed objects. The instances describe the 
actual physical or logical components of the managed 
rural land system. 
Message Class. All alarm messages produced by a 
specific managed object are organized into a message 
class hierarchy using the class/subclass relation. 
Introduction of message classes simplifies the decision- 
making process of rural land use monitoring. Each 
message class in the hierarchy contains a message- 
parsing pattern and a translation schema, common to a 
subset of all messages that belong to this class. 
Correlation class. A correlation class is a generalized 
description of the state of the monitoring system based 
on interpretation of events of the monitoring system. 
The conditions under which the correlation is asserted 
are described in the correlation rules. Each assertion 
creates an instance of a correlation class. A correlation 
class contains components, a message template, and 
parameters. The components may be managed objects, 
alarm messages, or other correlations. Correlation 
components are used to pass information from a 
correlation rule to the asserted correlation. Parameters 
provide information about a correlation to higher-level 
correlations. 
Correlation Rules. Correlation rules recognize events 
and assert correlations. Different correlation rules may 
assert the same type of correlation. The conditional part 
of a rule is a Boolean pattern built upon primary terms 
and relations. The primary terms are messages, 
managed objects, correlations, and tests. The action 
part of the rule contains executable commands. 
6. PERFORMANCE MONITORING 
One of the key elements of performance management is 
performance monitoring of rural land system. Expert 
system can be used to support the performance 
management (Wagenbauer and Nejdl, 1993). In order 
to effectively manage an rural land system, the 
administrator of the rural land system must be able to 
determine when rural land, equipment and facilities 
within the rural land system are operating in a 
degraded mode. The administrator must also be able to 
determine where the rural land is in legal or illegal 
state. 
6.1 Monitoring Forms 
Typically, the performance management of rural land 
system can be divided into monitoring and control 
aspects. Performance monitoring refers to the collection 
of information on the state of rural land use, while 
control refers to actions taken to improve the 
performance of rural land system. The performance 
monitoring system must be flexible enough to satisfy 
current and future performance monitoring needs 
regardless of the technology or type of rural land and 
rural land system equipment being monitored. The 
performance monitoring can take different forms as the 
followings. 
(1)One common use is hunting for a specific problem 
of rural land use. 
(2)Another situation involves global monitoring. The 
administrator will probably want to be advised of 
developing problems before they can affect the 
operation of rural land system. 
(3)A third possible use is the historical analysis of 
trends of rural land use and rural land quality. It 
may be desirable to be able perform statistical 
analysis of various performance data over some 
period of time. 
6.2 Monitoring Methods 
The most elemental level of performance monitoring 
ultimately depends on measuring information about 
rural land system. Measurements may take the form of 
counters. Counters are cumulative indicators that 
measure the occurrences of some event or the total 
number of units of some quantity. A current data of 
managed object class is a collection of counters and 
gauges that are used to monitor the state of rural land 
system. There are different subclasses of current data. 
Each subclass of current data corresponds to the type of 
194 Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998