Volume Two - Academic Conferences

Cristina Wanzeller and Orlando Belo
sufficient processes’ descriptions, properly structured and applicable, according to the organization’s
own needs. If we have such description, we will ask for an effective and flexible mechanism to help
the matching of the current problem with the most promising mining processes. Knowledge
management systems focus on knowledge and experience sharing. They enhance organization
capabilities by externalizing knowledge of its employees and combine them in novel forms. It breaks
up rigid processes and enables much richer interaction possibilities and creativity.
3. Representing usage analysis experience
Case representation is a key issue in CBR. The case based representation model must support a
comprehensive description of WUM experiences, regarding the nature and requirements of such
process development. A case is defined as a WUM process, corresponding to a successful usage
analysis example. The case description is structured according to the domain problem and the
applied solution (Table 1). We also defined a set of fundamental dimensions (D, T, P, A and K) to
organize items of case’s description. The P dimension contains general attributes of WUM process
description, involving problem (Pp) and solution aspects (Ps).
Table 1: WUM process main item descriptors
Case representation
Problem Dataset and variables metadata (D)
Problem type (T): activity, analysis goals and application areas
Process date and requisites (Pp)
Solution Mining Activities (A): DM tool and modelling and transformation stages
Knowledge (K): Discoveries and general and specific facts
Process general information (Ps)
The case problem description comprises: metadata characterizing the data (D), at dataset and
individual variables level; categorizations of the WUM problem type (T), mainly in terms of
abstractions such as Web site main activity, analysis goals and application areas; and process data
and evaluation criteria (Pp). The site activity may be “higher education” or something more detailed.
An analysis goal reflects a kind of WUM problem, for example some general like “determine access
order of pages and items”. The application areas are meant as the possible uses of the discoveries
(e.g. “impact analysis”). To allow several levels of subdivision in more sub-areas, the application
areas are organized in a dynamic hierarchy. This hierarchy provides a flexible way to define more
subtle and refined application areas concerning the eLearning domain. The process requisites
respects to criteria desired for the process results (e.g. level of precision).
The applied solution is essentially defined by: a sequence of activities (A), including transformation
and modelling stages, the involved data items and the model parameter settings; prior and derived
knowledge (K), concerning to facts that affected the analysis, the extracted knowledge and the
relations to such facts; and general information about the WUM process (Ps). The most important
aspects of the solution description are the details which may be used to reproduce with fidelity the
WUM process. Such details are usually the main ingredients of the DM activity success.
We also have a context description item to organize cases in terms of a site or particular sections
(e.g. curse). This item is a logic container for cases description features. The context may be
associated with some aspects, namely dataset, activity, specific fact and general fact. Besides CBR
principles (Kolodner 1993; Aamodt and Plaza 1994; Richter 1995; Mantaras et al. 2005), the
Predictive Model Markup Language (PMML) standard was an important orientation. PMML is a XML
based standard to define and share statistical and DM models across compliant applications The
DM/KD/WUM domains are complex, the respective vocabulary is diverse, even at basic aspects,
hindering the knowledge modelling. So, PMML provided accepted vocabulary to adopt and insights on
how to represent DM processes.
4. Acquiring and reusing experience
A straight reuse of one solution is quite possible in the WUM domain, since recurrent problems are
common. Still, becomes necessary to enable to help users on identifying the most plausible strategies
to address the problem at hands. We also need simple ways for acquiring items of problem and
solution description, in order to submit easily new problems and gather efficiently the relevant know
how of successful processes. The CBR paradigm brings a key opportunity to our knowledge base,
providing inherently a proper way for attending these demands. Coupling CBR intrinsic functionalities
with components to attend additional needs, we devised an integrated system to fulfil our intents.
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