Major components

The major components of ECliPS are: Data Explorer, Rule (or Knowledge) Explorer, Inference Engine, Graphical Interface, Search and Reporting Facilities. In many respects ECliPS is similar to an typical expert or decision support system, but unlike other commercial expert systems, both the knowledge presentation and inference process in ECliPS are more transparent to the user, and it is much easier to use. In this section we describe the first two components, Data and Rule Explorers, which help to manage the data and knowledge bases, respectively. Other components will be briefly discussed in the next section that explains how the system arrives to its conclusions.

Data explorer

Data explorer

Fig. 1. Data explorer

The Data Explorer (Fig. 1) organizes information about climate variables based on geographical hierarchy. The user can easily create his/her own geographical domain with the necessary level of details. The data for each climate variable is kept in a separate Excel file and the descriptive information in a Word file.

Fig. 2. Edit form for a climate variable.

Fig. 2. Edit form for a climate variable.

Each variable has four attributes: name, region, season/month, and base period against which the anomalies are calculated (Fig. 2). The data can be presented as a set of numerical values and/or classes (categories), including fuzzy sets, with the corresponding degrees of membership (Fig. 3). The Data Explorer also allows the user to see a list of rules, in which the selected variable is used either as predictand or predictor (Fig. 4). This is a quick and convenient way to estimate the role of the variable in the knowledge domain, which in our case is (ultimately) the entire climate system. It also significantly simplifies the construction of a complex forecasting project with multiple links.

Fig. 3. Data template.

Fig. 3. Data template.
Fig. 4. A list of rules that describe factors affecting the timing and magnitude of ENSO.

Fig. 4. A list of rules that describe factors affecting the timing and magnitude of ENSO.


 

Rule explorer

Fig. 5. Rule Template.

Fig. 5. Rule Template.

The domain knowledge in ECliPS is presented as a set of rules. Most commonly, the rules are in the IF-THEN form. For example, a rule may look like

IF ENSO event = warm,
AND Aleutian low circulation type = W1,
THEN winter SAT in the Bering Sea = above normal;
CF = 50.

Here CF is the confidence factor for the rule. Despite the simplicity, this type of rules is very powerful and versatile in expressing  relationships between climate variables.

Fig. 6. Rule edit form.

Fig. 6. Rule edit form.

It is important to note that the data and code for each rule are placed in a separate Excel file. This provides substantial  flexibility in preparing a rule for the knowledge base. In most cases it would be suffice to use a provided template (such as the one in Fig. 5), where the user can simply fill in the table. The advanced users, however, who are familiar with Visual Basic for Excel, can write their own code. Another advantage of this rule information storage is that the user can easily experiment with each rule separately and develop a better feeling of confidence in it.

Fig. 7. Rule Explorer.

Fig. 7. Rule Explorer.

Common management tasks, such as inserting new rule, editing (Fig. 6), deleting, sorting, etc., are performed using the Rule Explorer (Fig. 7). The number of variables in the IF part of a rule is unlimited.