A conceptual database design approach based on rules and heuristics

Conceptual and logical database design are complex tasks for non-expert designers. Currently, the popular data models for conceptual and logical database design are the entity–relationship (ER) and the relational model, respectively. Logical design methodologies for relational databases have relied on mathematically rigorous approaches which are impractical, or textbook approaches which do not provide the rich constructs to capture real applications. Consequently, designers have to use their intuition to develop their own rules and heuristics. There is a need, therefore, to develop practical rules and heuristics that can be used to handle the complexity of design in real applications. This paper proposes a realistic and detailed approach for conceptual design using the ER model for relational databases. The approach is based on four rules that specify the order in which various types of relationships must be modelled, three rules that pertain to detection of derived relationships, and three heuristics based on observation of constructs in real applications. The approach is illustrated by many examples.     

Identifying the relevance of quality dimensions contributing to universal access of social Web applications for collaborative writing on mobile devices: an empirical study

When used in a mobile ecosystem, social Web applications are commonly criticized due to their poor quality. We believe this is accounted for by the inadequacy of current approaches for their evaluation as well as the lack of suitable quality models. With an objective to address the aforementioned issues, this paper introduces a quality model that captures the particularities of social Web applications when used on mobile devices. Drawing on the comprehensive literature review, a finite set of performance variables (items, attributes, and categories) that contribute to the mobile quality of social Web applications was identified and subsequently employed for the purpose of designing a conceptual model in the form of a mobile quality requirements tree. An empirical study was then carried out to assess the reliability and validity of the conceptual model and pertaining measuring instrument. During the study, participants accomplished predefined scenarios of interaction with a representative sample of social Web applications for collaborative writing and evaluated their mobile quality by completing the post-use questionnaire. An analysis of data collected from end users uncovered a relevance of performance variables at different levels of granularity in a mobile quality requirements tree as well as pros and cons of evaluated collaborative editors.     

Linking GIS and water resources management models: an object-oriented method

Many challenges are associated with the integration of geographic information systems (GISs) with models in specific applications. One of them is adapting models to the environment of GISs. Unique aspects of water resource management problems require a special approach to development of GIS data structures. Expanded development of GIS applications for handling water resources management analysis can be assisted by use of an object oriented approach. In this paper, we model a river basin water allocation problem as a collection of spatial and thematic objects. A conceptual GIS data model is formulated to integrate the physical and logical components of the modeling problem into an operational framework, based on which, extended GIS functions are developed to implement a tight linkage between the GIS and the water resources management model. Through the object-oriented approach, data, models and users interfaces are integrated in the GIS environment, creating great flexibility for modeling and analysis. The concept and methodology described in this paper is also applicable to connecting GIS with models in other fields that have a spatial dimension and hence to which GIS can provide a powerful additional component of the modeler’s tool kit.     

Semi-automated buildup and calibration of conceptual sewer models

Building conceptual sewer models can be a time-consuming task, especially for large or complex models or models that require input data that might be difficult/tedious to obtain manually.This paper presents a semi-automated procedure for the buildup and calibration of one conceptual model that requires detailed input data such as throttle dimensions, pump curves or water level-storage relations. The procedure uses a hydrodynamic model as basis for sewer network data to create the model layout. A standardised series of composite rainfall events is applied to the hydrodynamic model in order to obtain the necessary reference data for the automated calibration of the conceptual model.Both model buildup and calibration are illustrated by means of a case study. Comparison of results of the hydrodynamic and conceptual model for a 1 year long-term series shows that the automated buildup and calibration can lead to an accurate conceptual model in short time.     

Best practices for conceptual modelling in environmental planning and management

Conceptual modelling is used in many fields with a varying degree of formality. In environmental applications, conceptual models are used to express relationships, explore and test ideas, check inference and causality, identify knowledge and data gaps, synchronize mental models and build consensus, and to highlight key or dominant processes. Due to their sometimes apparent simplicity, development and use of a conceptual model is often an attractive option when tackling an environmental problem situation. However, we have experienced many examples where conceptual modelling has failed to effectively assist in the resolution of environmental problems. This paper explores development and application of conceptual modelling to environmental problems, and identifies a range of best practices for environmental scientists and managers that include considerations of stakeholder participation and trust, model development and representation, integration of different and disparate conceptual models, model maturation, testing, and transition to application within the problem situation.     

Modeling semantic information in engineering applications: a review

Due to the latest advances of information technology and the increasing complexity of engineering applications, it is becoming more and more important to model semantic information. There are many modeling methodologies to do the work of modeling semantic information instead of natural language processing. Since this field is very broad, the comparison discussed here is not an exhaustive study but rather the partial views of the coauthors from our own perspectives. In the present paper we give a review of the literature of conceptual models especially static one and then classify them into four type models namely structure-based model, object-oriented model, knowledge semantic-based model, and web semantic-based model. Based on the classification given above, a hierarchy structured criteria is given. According to the criteria we pick one or two representative conceptual models from each type to conduct the comparison. We compare the following five aspects of conceptual models: expressivity, clarity, semantics, formal foundation, and application fields. The comparative study shows that different models have different features and fit different fields of engineering applications. The present comparison study is useful for users to understand and choose right conceptual models combining with specific requirements of engineering applications.     

B2B集成技术的体系结构

介绍了B2B集成技术的体系结构和概念上的模型，用来支持统一概念集成模型中并发的A2A和B2B集成。概念集成模型通过设计时仓库完成，集成模型作为元数据存储在设计时仓库。B2B集成技术的执行时范例完成实际的应用和贸易伙伴商务交易遵循编译的方法，根据存储在设计时仓库中的集成模型，执行器完成实际的集成实例。     

An integrated temporal data model incorporating time series concept

Most temporal data models have concentrated on describing temporal data based on versioning of objects, tuples or attributes. The concept of time series, which is often needed in temporal applications, does not fit well within these models. The goal of this paper is to propose a generalized temporal database model that integrates the modeling of both version-based and time-series based temporal data into a single conceptual framework. The concept of calendar is also integrated into our proposed model. We also discuss how a conceptual Extended-ER design in our model can be mapped to an object-oriented or relational database implementation.     

A Method for Developing Component-Oriented Applications: A Use-Context Driven Approach Toward Component Coordination

In this paper, we propose a methodology for the development of component-oriented applications based on the Component Coordination Model (CCM) that is embedded into applications during software architecture design. The method is general enough to support the conceptual level of component-based software development. It provides a set of guidelines that ease developers during analysis and design phases. These guidelines are defined as processes for developing increasingly detailed models of constructing software systems. The CCM is driven by the use-context model, which directly reflects the role model that abstracts system behaviors as a computational organization comprising various role relationships. It then focuses on exposing the design of software components to be separated from their execution contexts. These separate concerns, including computation, coordination, and policies imposed on a given use-context, form the principal concept of our approach. A case study using the proposed method has been demonstrated in order to provide the feasibility of the introduced approach.     

EHR application portfolio and hospital performance: Effects across hospitals with varying administrative scale and clinical complexity

Electronic Health Record (EHR) has the potential to transform the work required to create and deliver healthcare services. This has triggered large-scale adoption across hospitals. However, whether all hospitals obtain a similar effect from their EHR implementations remains an important question because there are significant differences differences in characteristics of hospitals adopting these systems. To examine differences in effects across hospitals, we examine whether the impacts of EHR applications are contingent on work domains, by assessing performance effects across hospitals with varying administrative scale and clinical complexity. Because EHRs constitute a suite of applications with different functionalities, examining the effects of different sets of applications is challenging due to nonlinear interdependencies between applications. Therefore, we use an archetype approach, identifying synergistic EHR (EHRSYN) archetype as an ideal portfolio—a conceptual anchor for a hospital’s EHR portfolio. We test contingencies by combining this technology archetype with the work domains—administrative scale and clinical complexity. We test our hypotheses using empirical data from 137 hospitals in California, hypothesizing the differences in effects of EHRs on financial, operational, and clinical performances across hospitals with different administrative scales (size) and clinical complexities (case-mix) of work. While hospitals gain the most by implementing a portfolio close to the EHRSYN archetype, our nuanced models reveal that the benefits of such portfolios increase for large hospitals and are greater for hospitals treating less complex cases. These findings underscore how variations in applications used and work domains demarcate boundaries related to the performance effects of EHRs. We present a detailed discussion of the theoretical contributions and practical implications of our findings.     

Developing secure data warehouses with a UML extension

Data Warehouses (DWs), Multidimensional (MD) Databases, and On-Line Analytical Processing Applications are used as a very powerful mechanism for discovering crucial business information. Considering the extreme importance of the information managed by these kinds of applications, it is essential to specify security measures from the early stages of the DW design in the MD modeling process, and enforce them. In the past years, some proposals for representing main MD modeling properties at the conceptual level have been stated. Nevertheless, none of these proposals considers security issues as an important element in its model, so they do not allow us to specify confidentiality constraints to be enforced by the applications that will use these MD models. In this paper, we will discuss the specific confidentiality problems regarding DWs as well as present an extension of the Unified Modeling Language for specifying security constraints in the conceptual MD modeling, thereby allowing us to design secure DWs. One key advantage of our approach is that we accomplish the conceptual modeling of secure DWs independently of the target platform where the DW has to be implemented, allowing the implementation of the corresponding DWs on any secure commercial database management system. Finally, we will present a case study to show how a conceptual model designed with our approach can be directly implemented on top of Oracle 10g.     

Design of statistical databases: A methodology for the conceptual step

The aim of the conceptual step in database design is to describe data involving in the application in a formal and abstract way, without any concern to the specific model and language chosen for the implementation. In statistical applications, data are described at different levels of aggregation, from elementary facts of the reality to complex aggregations such as classifications, time series, indexes. The paper describes a methodology for conceptual design of statistical databases that provides the designer suitable strategies for defining such different levels of aggregation starting from user requirements, and checking the completeness, coherence and minimality of the conceptual schema at the different levels. The methodology makes use of two data models for the representation of data: for elementary data the Entity-Relationship model, widely used in database applications, and for summary data a new model is proposed, designed to be an effective trade-off between expressive power and simplicity of use.     

Integrated assessment modelling for water resource allocation and management: A generalised conceptual framework

Nodal network approaches are a common framework for considering water allocation in river basins. In this type of model framework, a river basin is represented as a series of nodes, where nodes generally represent key points of extraction or instream use. When considering water allocation, agricultural production and other water use decisions generally interact with the stream system in two ways: they can affect the generation of runoff and thus the volume of water reaching the stream; or, they may involve direct extraction or use of water once it has reached the stream. Models are generally required to consider the influence of these decisions on flows and downstream water availability, as well as the influence of flows on the productive, passive use and environmental values of water. This paper provides a generalised conceptual framework for considering these types of interactions and their representation in integrated water allocation models. Applications of this framework to three very different case studies are outlined.     

Estimation of water and salt generation from unregulated upland catchments

Water and salt export to rivers is of particular importance in large catchments, such as Australia’s Murray-Darling Basin, where there are multiple users of the water resource. Comparing estimates of water and salt generated from upland catchments across large areas is difficult due to the lack of a comparable, consistent approach. River routing models are currently used to model water and salt movement along regulated reaches. However methods are still required to predict the individual contributions of water and salt from unregulated upland catchments to feed into these river routing models. The 2CSalt model has been developed to predict monthly water and salt export from these upland catchments. 2CSalt makes use of existing regional data sets such as topography (digital elevation models) and hydrogeology/salinity (Groundwater Flow Systems). 2CSalt was developed using the “TIME” modelling framework which allowed for a rapid development cycle through the reuse of existing and tested components. The results from current applications of the model show a strong match with measured data.     

Flood regulation using nonlinear model predictive control

In this paper the flood problem of the river Demer, a river located in Belgium, is discussed. First a simplified model of the Demer basin is derived based on the conceptual reservoir modeling concept. This model was calibrated to simulations results with a more detailed full hydrodynamic model. Afterwards, the focus is shifted to a nonlinear model predictive controller (NMPC) which is based on a new semi-condensed optimization procedure combined with a line search approach. Finally, simulations are performed based on historical data in which the NMPC is compared with the current control strategy used by the local water administration. Uncertainties are added to the rainfall predictions in order to assess the robustness of the NMPC.     

A Method for Conceptualising Legal Domains. An Example from the Dutch Unemployment Benefits Act

There has been much talk of the need to build intermediate models of the expertise required preparatory to constructing a knowledge-based system in the legal domain. Such models offer advantages for verification, validation, maintenance and reuse. As yet, however, few such models have been reported at a useful level of detail. In this paper we describe a method for conceptualising legal domains as well as its application to a substantial fragment of the Dutch Unemployment Benefits Act (DUBA).We first discuss the intermediate models (called expertise models), then present a three-stage method for their construction, drawing on the CommonKADS work in knowledge acquisition, conceptual models of statute law, and the KANT method of knowledge analysis. Subsequently, we describe how these techniques were applied to the DUBA, and provide detailed examples of the resulting model. Finally, conclusions on the framework and guidelines are given as well as means of recording and presenting the various design choices.