Modeling views in the layered view model for XML using UML

In data engineering, view formalisms are used to provide flexibility to users and user applications by allowing them to extract and elaborate data from the stored data sources. Conversely, since the introduction of Extensible Markup Language (XML), it is fast emerging as the dominant standard for storing, describing, and interchanging data among various web and heterogeneous data sources. In combination with XML Schema, XML provides rich facilities for defining and constraining user-defined data semantics and properties, a feature that is unique to XML. In this context, it is interesting to investigate traditional database features, such as view models and view design techniques for XML. However, traditional view formalisms are strongly coupled to the data language and its syntax, thus it proves to be a difficult task to support views in the case of semi-structured data models. Therefore, in this paper we propose a Layered View Model (LVM) for XML with conceptual and schemata extensions. Here our work is three-fold; first we propose an approach to separate the implementation and conceptual aspects of the views that provides a clear separation of concerns, thus, allowing analysis and design of views to be separated from their implementation. Secondly, we define representations to express and construct these views at the conceptual level. Thirdly, we define a view transformation methodology for XML views in the LVM, which carries out automated transformation to a view schema and a view query expression in an appropriate query language. Also, to validate and apply the LVM concepts, methods and transformations developed, we propose a view-driven application development framework with the flexibility to develop web and database applications for XML, at varying levels of abstraction

Developing a distributed electronic health-record store for India

The DIGHT project is addressing the problem of building a scalable and highly available information store for the Electronic Health Records (EHRs) of the over one billion citizens of India

Conference Web Site Redesign

Sustainable Resources was a non-profit organization based out of Boulder, CO that, at the time of this project hosted yearly conferences to help find solutions to world poverty. Although, the previous web site had a professional appearance, it was not meeting their needs with regards to usability, extensibility, and maintainability, as they had been forced to rely heavily on a transient volunteer IT labor base. The aim of this project was to address their functional and maintenance problems. The application\u27s front-end was built in adherence to the Model -view-Controller (MVC) design pattern and implemented using the Jakarta Struts framework and consisted of, a JSP interface. Hibernate was used as the database persistence layer and the entire data model was completely replaced, as certain data fields were being duplicated in the former system. While giving Sustainable Resources the same functionality they had previously enjoyed, the new application enabled the site\u27s administrators to effectively maintain parts of the application without IT support and supplied them with the necessary documentation to assist future developers with upgrades

A Framework for Executable Systems Modeling

Systems Modeling Language (SysML), like its parent language, the Unified Modeling Language (UML), consists of a number of independently derived model languages (i.e. state charts, activity models etc.) which have been co-opted into a single modeling framework. This, together with the lack of an overarching meta-model that supports uniform semantics across the various diagram types, has resulted in a large unwieldy and informal language schema. Additionally, SysML does not offer a built in framework for managing time and the scheduling of time based events in a simulation. In response to these challenges, a number of auxiliary standards have been offered by the Object Management Group (OMG); most pertinent here are the foundational UML subset (fUML), Action language for fUML (Alf), and the UML profile for Modeling and Analysis of Real Time and Embedded Systems (MARTE). However, there remains a lack of a similar treatment of SysML tailored towards precise and formal modeling in the systems engineering domain. This work addresses this gap by offering refined semantics for SysML akin to fUML and MARTE standards, aimed at primarily supporting the development of time based simulation models typically applied for model verification and validation in systems engineering. The result of this work offers an Executable Systems Modeling Language (ESysML) and a prototype modeling tool that serves as an implementation test bed for the ESysML language. Additionally a model development process is offered to guide user appropriation of the provided framework for model building

Consistency in multi-viewpoint architectural design

This thesis presents a framework that aids in preserving consistency in multi-viewpoint designs. In a multi-viewpoint design each stakeholder constructs his own design part. We call each stakeholder’s design part the view of that stakeholder. To construct his view, a stakeholder has a viewpoint. This viewpoint defines the design concepts, the notation and the tool support that the stakeholder uses. The framework presented in this thesis focuses on architectural multiviewpoint design of distributed systems. A distributed system is a system of which the parts execute on different physical system nodes. Interaction between the system parts plays an important role in such systems. An example of a distributed system is a mobile communication network. In such a network, the parts of the system execute on e.g. the mobile telephones of the clients, the desktops of the employees of the network operator and the mobile access points. Architectural design is the area of design that focuses on higher levels of abstraction in the design process. The lowest level of abstraction that we consider is the level at which the system parts correspond to parts that can be deployed on communication middleware. Using our framework, consistency is preserved through inter-viewpoint relations and consistency rules that must be specified by the stakeholders. The stakeholders use inter-viewpoint relations to specify how one view relates to another and they use consistency rules to specify what rules must at least be satisfied in a consistent design. To aid in preserving consistency, our framework defines: – a common set of basic design concepts; – pre-defined inter-viewpoint relations; – pre-defined consistency rules; – a language to represent inter-viewpoint relations and consistency rules. The basic design concepts that the framework defines have been adopted from earlier work. These concepts were developed by carefully examining the area of distributed systems design. Using our framework, viewpoint-specific design concepts must be defined as compositions or specializations of these basic concepts. Hence, the basic concepts form a common vocabulary that the different stakeholders can use to understand each other’s designs. The framework pre-defines inter-viewpoint relations that can be reused to specify how one view relates to another. The two main types of inter-viewpoint relations that it pre-defines are: refinement relations and overlap relations. Refinement relations exist between views that (partly) consider the same design concerns at different levels of abstraction. Overlap relations exist between views that (partly) consider the same design concerns at the same level of abstraction. We derived the pre-defined relations by examining existing frameworks for multi-viewpoint design and extracting frequently occurring relations between viewpoints in these frameworks. If a pre-defined inter-viewpoint relation exists between two views, this implies that certain consistency rules must be satisfied. Specifically, if two views have a refinement relation, this implies that one must preserve the system properties specified by the other. If two views have an overlap relation, this implies that the two views must be equivalent with respect to the overlap that they have. Our framework pre-defines consistency rules that can be re-used to verify these properties. We define an architecture for tool-support to aid in specifying view relations and consistency rules and to check whether the specified consistency rules hold. The architecture contains the pre-defined relations and consistency rules, such that they can be re-used. As a case study for the framework we define adapted versions of the RM-ODP enterprise, computational and information viewpoints, using our framework. We define the concepts from these viewpoints as compositions of the basic concepts. Also, we define the relations between views from these viewpoints, as well as the corresponding consistency rules, using the relations and consistency rules that are pre-defined by the framework. The results of the case study support the claim that our framework aids in preserving consistency in multi-viewpoint designs