Conceptual Modeling Method Research Articles

Modeling events as entities in object-oriented conceptual modeling languages

Most current conceptual modeling languages and methods do not model events as entities. We argue that, at least in object-oriented (O-O) languages, modeling events as entities provides substantial benefits. We show that a method for behavioral modeling that deals with event and entity types in a uniform way may yield better behavioral schemas. The proposed method makes extensive use of language constructs such as constraints, derived types, derivation rules, type specializations and operations, which are present in all complete O-O conceptual modeling languages. The method can be adapted to most O-O languages. In this paper we explain its adaptation to the UML.

Ontology based object-oriented domain modelling: fundamental concepts

Understanding the business is an important step in information system (IS) development. Conceptual models are descriptions of the organizational context for which a system is developed, and are used to help understanding this context. However, conceptual modelling methods do not provide well-formalized ways to create domain descriptions. On the other hand, in the area of IS design and software modelling, languages exist (such as UML) that possess a high level of formality. Extending the use of these IS design languages to conceptual modelling, even though they have not been specifically intended for this, can lead to several advantages. In particular, it can enable the use of similar notation in several stages of system development. However, while object-oriented constructs such as “object” and “operation” have clear meaning in the context of software design, it is not clear what they might mean in terms of the application domain, and no rules or guidelines exist for using them to create useful descriptions of such domains. This paper suggests specific semantics for object-oriented constructs based on a mapping between ontologically derived concepts and object-oriented language constructs. The paper also proposes modelling rules to guide the construction of object-oriented conceptual models and to assure that such models describe only ontologically feasible application domain situations. While the results are applicable to object-oriented constructs in general, UML is used as an example. A case study to test the use of the proposed semantics and modelling rules is described.

Research Commentary: Information Systems and Conceptual Modeling—A Research Agenda

Within the information systems field, the task of conceptual modeling involves building a representation of selected phenomena in some domain. High-quality conceptual modeling work is important because it facilitates early detection and correction of system development errors. It also plays an increasingly important role in activities like business process reengineering and documentation of best-practice data and process models in enterprise resource planning systems. Yet little research has been undertaken on many aspects of conceptual modeling. In this paper, we propose a framework to motivate research that addresses the following fundamental question: How can we model the world to better facilitate our developing, implementing, using, and maintaining more valuable information systems? The framework comprises four elements: conceptual-modeling grammars, conceptual-modeling methods, conceptual-modeling scripts, and conceptual-modeling contexts. We provide examples of the types of research that have already been undertaken on each element and illustrate research opportunities that exist.

A Conceptual Model and Rule-Based Query Language for HTML

Most documents available over the Web conform to the HTML specification. Such documents are hierarchically structured in nature. The existing data models for the Web either fail to capture the hierarchical structure within the documents or can only provide a very low level representation of such hierarchical structure. How to represent and query HTML documents at a higher level is an important issue. In this paper, we first propose a novel conceptual model for HTML. This conceptual model has only a few simple constructs but is able to represent the complex hierarchical structure within HTML documents at a level that is close to human conceptualization/visualization of the documents. We also describe how to convert HTML documents based on this conceptual model. Using the conceptual model and conversion method, one can capture the essence (i.e., semistructure) of HTML documents in a natural and simple way. Based on this conceptual model, we then present a rule-based language to query HTML documents over the Internet. This language provides a simple but very powerful way to query both intra-document structures and inter-document structures and allows the query results to be restructured. Being rule-based, it naturally supports negation and recursion and therefore is more expressive than SQL-based languages. A logical semantics is also provided.

Modelling runoff and diffuse pollution loads in urban areas

This paper presents a simple approach for estimating long-term runoff and diffuse pollution loads in urban catchments, and discusses conceptual modelling methods for simulating daily runoff and pollution loads. The modelling results for several catchments in Australian capital cities are presented. The study indicates that long-term and daily runoff can be estimated reasonably accurately using simple approaches. However, the water quality characteristic can vary considerably between catchments, and in the absence of data, the models can only provide a guide to the probable range of diffuse pollution load generated from a catchment.

Modelling runoff and diffuse pollution loads in urban areas

This paper presents a simple approach for estimating long-term runoff and diffuse pollution loads in urban catchments, and discusses conceptual modelling methods for simulating daily runoff and pollution loads. The modelling results for several catchments in Australian capital cities are presented. The shidy indicates that long-term and daily runoff can be estimated reasonably accurately using simple approaches. However, the water quality characteristic can vary considerably between catchments, and in the absence of data, the models can only provide a guide to the probable range of diffuse pollution load generated from a catchment.

Grammatical Conversion of Descriptive Narrative - an application of discourse analysis in conceptual modelling

Fact-oriented conceptual modelling begins with the search for facts about a universe of discourse (UoD). These facts may be obtained from many sources, including information systems reports, tables, manuals and descriptive narrative both verbal and written. This paper presents some initial findings that support the use of discourse analysis techniques as an approach to developing elementary fact based sentences for information systems conceptual schema development from written text. Although this discussion paper only considers the NIAM (fact-oriented) conceptual schema modelling method, the IS087 report from which the research case study is taken describes other conceptual methods for which the research contained in this paper could be applicable (e.g. Entity Relationship analysis). The case study could be modelled exactly in the form in which the text is initially found, but grammatical analysis focuses consideration on alternative, potentially better, expressions of a sentence, a theme which is described and demonstrated. As a result of having applied grammatical sentence simplification with co-ordinate clause splitting, each sentence could be expressed as a complete, finite, independent collection of declarative simple statements. The outcome from the application of the techniques described provides at a minimum a discourse analysis of descriptive narrative which will have retained its meaning and contextual integrity while at the same time providing a simplified and independent clause representation for input to the fact-oriented conceptual schema modelling procedure.

Combining Static and Dynamic Modelling Methods: A Comparison of Four Methods

A conceptual model of a system is an explicit description of the behaviour required of the system. Methods for conceptual modelling include entity-relationship (ER) modelling, data flow modelling, Jackson System Development (JSD) and several object-oriented analysis methods. Given the current diversity of modelling methods, it is important for teaching as well as using these methods to know what the relationships between them is and to be able to indicate what the (im)possibilities of integrating different methods are. This paper compares three classical modelling methods (ER, data flow, JSD) on their possibilities for integration and combination. It is shown that there is a common core of these methods, which centres around the concept of system transaction and that unifies the static view of a system taken by ER modelling, with the dynamic view taken by JSD and the functional view taken by data flow modelling. Several object-oriented analysis methods integrate these three views. This paper illustrates how this is done in the analysis stage of Object Modelling Technique. Finally, it is shown that the transaction decomposition table can be used as a pivot around which to combine different methods. The results of this paper can be used in teaching to explain the relationships and differences between the methods analysed here, and in system development practice to ease the transition from structured to object-oriented methods.

FLUID BALANCE AND ELECTROLYTE DISTRIBUTION IN THE HUMAN BODY*

This Memorandum presents a conceptual model and a mathematical method for computing the physiological fluid and electrolyte distribution for selected body compartments of an average, young, 70-kilogram human male. The mathematical procedure simulates the physiological subsystems by incorporating all the known chemical reactions and electrochemical relations which seem necessary to establish the fluid and electrolyte distribution. Because the whole body is being considered, the relatively large number of computations required argues that a computer be employed, The construction of the model and the mathematical background is given in heuristic form only, with reference to earlier papers for rigorous development. However, considerable detail is shown regarding the analysis of the computed results for a standard, steady-state, average, young, resting, 70-kg human male. Finally, the results of validation experiments, consisting of chemical stresses applied to the model, are discussed. In some cases, these results are compared with similar experiments in the biological literature, but in others reference is made to a companion paper by G. B. Bradham, et al. (1), in which particular laboratory validation experiments are described in detail. The results of these experiments indicate that the model is a valid supplementary tool for research in the clinical and the research laboratory as well as in theoretical physiology.