Nathalie Moreno

A survey on web modeling approaches for ubiquitous web applications

Purpose – Ubiquitous web applications (UWA) are a new type of web applications which are accessed in various contexts, i.e. through different devices, by users with various interests, at anytime from anyplace around the globe. For such full-fledged, complex software systems, a methodologically sound engineering approach in terms of model-driven engineering (MDE) is crucial. Several modeling approaches have already been proposed that capture the ubiquitous nature of web applications, each of them having different origins, pursuing different goals and providing a pantheon of concepts. This paper aims to give an in-depth comparison of seven modeling approaches supporting the development of UWAs. Design/methodology/approach – This methodology is conducted by applying a detailed set of evaluation criteria and by demonstrating its applicability on basis of an exemplary tourism web application. In particular, five commonly found ubiquitous scenarios are investigated, thus providing initial insight into the modeling concepts of each approach as well as to facilitate their comparability. Findings – The results gained indicate that many modeling approaches lack a proper MDE foundation in terms of meta-models and tool support. The proposed modeling mechanisms for ubiquity are often limited, since they neither cover all relevant context factors in an explicit, self-contained, and extensible way, nor allow for a wide spectrum of extensible adaptation operations. The provided modeling concepts frequently do not allow dealing with all different parts of a web application in terms of its content, hypertext, and presentation levels as well as their structural and behavioral features. Finally, current modeling approaches do not reflect the crosscutting nature of ubiquity but rather intermingle context and adaptation issues with the core parts of a web application, thus hampering maintainability and extensibility. Originality/value – Different from other surveys in the area of modeling web applications, this paper specifically considers modeling concepts for their ubiquitous nature, together with an investigation of available support for MDD in a comprehensive way, using a well-defined as well as fine-grained catalogue of more than 30 evaluation criteria.

A UML 2.0 profile for WebML modeling

In recent years, we have witnessed how the Web Engineering community considers the use of standard UML notation, techniques and supporting tools for modeling Web systems, including the adaptation of their own modeling languages, representation diagrams and development processes to UML. This interest for being MOF and UML-compliant arises from the increasing need to be able to interoperate with other notations and tools, and to exchange data and models, thus facilitating and improving reuse. WebML, like any other Domain Specific Language (DSL), allows to express in a precise and natural way the concepts and mechanisms of its domain of reference. However, it cannot fully interoperate with other notations, nor can it be integrated with other tools. As a solution to these requirements, in this paper we describe a UML 2.0 profile for WebML which allows WebML models to be used in conjunction with other notations and modeling tools.

An Overview Of Model-Driven Web Engineering and the Mda

1. INTRODUCTION Model-Driven Software Development (MDSD) is becoming a widely accepted approach for developing complex distributed applications. MDSD advocates the use of models as the key artifacts in all phases of development, from system specification and analysis, to design and implementation. Each model usually addresses one concern, independently from the rest of the issues involved in the construction of the system. Thus, the basic functionality of the system can be separated from its final implementation; the business logic can be separated from the underlying platform technology, etc. The transformations between models enable the automated implementation of a system from the different models defined for it. Web Engineering is a specific domain in which MDSD can be successfully applied. Most of the technology is here to implement systems that exploit the Web paradigm, but the effective design of Web applications is still a concern: the complexity and requirements on Web applications are constantly growing, while the supporting technologies and platforms rapidly evolve. Existing model-driven Web engineering (MDWE) approaches already provide excellent methodologies and tools for the design and development of most kinds of Web applications. They address different concerns using

WebML modelling in UML

In recent years, we have witnessed how the Web Engineering community has started using the standard unified modelling language (UML) notation, techniques and supporting tools for modelling Web systems, which has led to the adaptation to UML of several existing modelling languages, notations and development processes. This interest for being MOF and UML-compliant arises from the increasing need to interoperate with other notations and tools, and to exchange data and models, thus facilitating reuse. WebML, like any other domain-specific language, allows one to express in a precise and natural way the concepts and mechanisms of its domain of reference. However, it cannot fully interoperate with other notations, nor be integrated with other model-based tools. As a solution to these requirements, a UML 2.0 profile for WebML which allows WebML models to be used in conjunction with other notations and modelling tools has been described. The paper also evaluates UML 2.0 as a platform for Web modelling and identifies some key requirements for making this version of the standard more usable.

Viewpoint co-evolution through coarse-grained changes and coupled transformations

Multi-viewpoint modeling is an effective technique to deal with the ever-growing complexity of large-scale systems. The evolution ofmulti-viewpoint system specifications is currently accomplished in terms of fine-grained atomic changes. Apart from being a very low-level and cumbersome strategy, it is also quite unnatural to system modelers, who think of model evolution in terms of coarse-grained high-level changes. In order to bridge this gap, we propose an approach to formally express and manipulate viewpoint changes in a high-level fashion, by structuring atomic changes into coarse-grained composite ones. These can also be used to formally define reconciling operations to adapt dependent views, using coupled transformations. We introduce a modeling language based on graph transformations and Maude for expressing both, the coarse-grained changes and the coupled transformations that propagate them to reestablish global consistency. We demonstrate the applicability of the approach by its application in the context of RM-ODP.

Tool support for model checking of web application designs

In this work we report our experience in applying model checking techniques to the analysis of static and dynamic properties of Web application models. We propose a mix of tools that facilitate model driven design of Web applications, automatic code generation, and automatic property verification. As recommended by current tendencies in the academic field, we bridge the gap between the tools by devising a set of MDA transformations between the different models. We show that such approach is feasible although we also highlight how current state-of-the-art industrial tools are still partially inadequate for providing seamless support to MDA approaches for industrial Web applications.

A model-based approach for integrating third party systems with web applications

New Web applications are rapidly moving from stand-alone systems to distributed applications that need to interoperate with third party systems, such as external Web services or legacy applications. In most cases, this integration is not properly addressed by current Web Engineering proposals, that either achieve it only at one single level (user interface, process, code or data), or assume the existence of a central conceptual model, something which is not always true in a service-oriented scenario. This paper presents a model-based framework that provides concepts and mechanisms for facilitating the high-level integration of Web applications with third party systems, allowing the manipulation of the external entities of such systems as native elements of our models.

Addressing New Concerns in Model-Driven Web Engineering Approaches

In the last few years, almost all model-driven Web Engineering approaches have evolved in response to the new challenges of Web systems design, which are due to new requirements and implementation technologies in the Web domain. The evolution implies the extension and adaptation of current approaches, in terms of new models, transformations and processes in order to incorporate new concerns or aspects. Such changes in a methodology are a risky and error-prone process. In this paper, we analyze different alternatives to address the evolution and in particular, the addition of a new concern in a Model-Driven Web Engineering approach: (a) extending the original method with an additional modeling concern, (b) merging the original proposal with another approach covering the specific concern and, (c) finally, we propose a an interoperable and architectural-centric approach that aims to reduce the impact of adding a new concern. We discuss the main advantages and drawbacks of each alternative.

From programming to modeling: our experience with a distributed software engineering course

Distributed Software Engineering (DSE) concepts in Computer Science (or Engineering) Degrees are commonly introduced using a hands-on approach mainly consisting of teaching a particular distributed and component-based technology platform (such as Java Enterprise Edition or Microsoft .NET) and proposing the students to develop a small distributed software application with it. Though this approach provides the students with some relevant practical knowledge, we believe that it is not the most appropriate way of teaching all the concepts and particularities of DSE. Thus, in this paper we report on our experience of redesigning an initial DSE course following a model-based approach. By raising the level of abstraction we gained modularity, separation of concerns and technology independence, while making the course evolve according to the latest trends in software development methods.

Managing Uncertain Complex Events in Web of Things Applications

A critical issue in the Web of Things (WoT) is the need to process and analyze the interactions of Web-interconnected real-world objects. Complex Event Processing (CEP) is a powerful technology for analyzing streams of information about real-time distributed events, coming from different sources, and for extracting conclusions from them. However, in many situations these events are not free from uncertainty, due to either unreliable data sources and networks, measurement uncertainty, or to the inability to determine whether an event has actually happened or not. This short research paper discusses how CEP systems can incorporate different kinds of uncertainty, both in the events and in the rules. A case study is used to validate the proposal, and we discuss the benefits and limitations of this CEP extension.