Qualitative Modelling Approach Research Articles

Modelling Expertise for KBS Development

The benefits of a qualitative modelling approach to building knowledge-based systems include better project control, communication between participants, more accurate validation and easier maintenance. Knowledge acquisition from experts will be more successful if a conceptual model is developed from a knowledge level description, to act as a publicly examinable basis for system design. Analytical tools are available to structure both content and process knowledge on paper, before any commitment is made to implementation. The role of abstraction in developing models of generic tasks as a set of templates for conceptual model development is reviewed, with particular regard to knowledge acquisition tools. Modelling problem-solving methods, especially for constructive tasks such as planning, is more difficult than modelling content knowledge. Epistemological support for conceptual abstraction, particularly at middle levels, remains inadequate.

Optimal Foraging for Complementary Resources

Foraging for complementary resources is widespread in nature. The conventional approaches to optimal foraging are inadequate to describe this phenomenon, since they are predicated on perfect substitution among alternative foods in terms of energy yield per unit time. A more qualitative modeling approach derived from economics is proposed to take explicitly into account the degree of resource substitutability for predators requiring balanced diets. The model yields hypotheses that differ markedly from those derived under the assumptions of perfect resource substitution. First, prey species cannot be ranked (ordinally or cardinally) in terms of their value to predators, since the benefits derived from consumption of one prey type depend on the quantities of complementary resources consumed. Second, prey selectivity is affected by the relative abundance of any potential food source. Third, when food resources are complementary predator fitness is greater on mixed diets than on single species diets.

Qualitative Consequences of Randomness in a Linear Kinetic System

SUMMARY Biological data, either by convenience or necessity, are often characterized by large spread, small sample size, non-stationarity, and other qualities that make it difficult or impossible to apply conventional statistical methods of analysis. This paper presents a qualitative modeling approach to the analysis of such data. The technique is illustrated by the analysis of data representing the uptake of acetylcholine by synaptic vesicles, and it is demonstrated that a number of properties of that biological process can be determined from what would normally be considered rather poor data. In particular, it is shown that a deterministic model in this case appears to be insufficient to represent the system and that at least two types of randomness are involved.