Carsten Radeck

CapView: functionality-aware visual mashup development for non-programmers

Building mashup applications from existing web resources becomes increasingly popular, and, in theory, accessible even for end users without programming skills. Current proposals for end user development of mashups mainly focus on visual wiring of component interfaces supplemented by recommendations on composition steps and a certain degree of automation. However, it is still a major challenge to provide an appropriate level of functional abstraction in order to visualize the functionality of a mashup and its components, and for composing on a functional level instead of merely assembling structural units. This becomes crucial, especially when non-programmers are the intended target group. In this paper, we propose CapView, a novel functionality-aware development view on running composite applications. CapView is part of the EDYRA platform and provides a functional overview of the mashup by abstracting from interface and wiring details. It enables users to understand mashup development as an assembly process that is centered on the capabilities of components and mashup fragments. We evaluate the concepts in a user study and present lessons learned.

Semantic Mediation Techniques for Composite Web Applications

The mashup paradigm allows end users to build custom web applications by combining data-exchanging components in order to fulfill specific needs. Since such building blocks typically originate from different third party vendors, compatibility issues at component interface level are inevitable. This decreases re-usability and requires skilled users or automatisms to provide the necessary mediation to solve such issues. However, current mashup proposals are very limited in this regard.

Estimating the Functionality of Mashup Applications for Assisted, Capability-centered End User Development

The mashup paradigm allows end users to build their own web applications consisting of several components in order to fulfill specific needs. Thereby, communicating on a non-technical level with non-programmers as end users is crucial. It is also necessary to assist them, for instance, by explaining inter-widget communication and by helping to understand a mashup’s functionality. However, prevalent mashup approaches provide no or limited concepts for these aspects. In this paper, we present our proposal for estimating and formalizing the functionality of mashup compositions based on capabilities of components and their communication links. It is the foundation for our end-user-development approach comprising several assistance mechanisms, like presenting the functionality of mashups and recommended composition steps. The concepts are implemented and evaluated by means of example applications and an expert evaluation.

Helping Non-programmers to Understand the Functionality of Composite Web Applications.

The mashup paradigm allows end users to build their own web applications by combining components in order to fulfill specific needs. Mashup development and usage are still cumbersome tasks for non-programmers, for instance, when it comes to understanding the composite nature of mashups and their functionality. Nonprogrammers may struggle to use components as intended, especially if the latter provide capabilities in combination, and may lack awareness for inter-widget communication (IWC). Prevalent mashup approaches provide no or limited concepts for these aspects, resulting in more or less successful trial and error strategies of users. In this paper, we present our proposal for assisting non-programmers to understand and leverage the functionality of components and their interplay in a mashup. Based on annotated component descriptions, interactive explanations and step-wise instructions are generated and presented directly in context of components’ user interface (UI). In addition, active IWC is visualized to foster awareness of users. We describe the iterative design which led us from early approaches towards our current solution. The concepts are implemented in our mashup platform and evaluated by means of a user study. The results indicate that our solutions help non-programmers to better understand the functionality of composite web application (CWA).

Triple-based Sharing of Context-Aware Composite Web Applications for Non-programmers

Composite web applications are a promising way to support the long tail of user needs. While most mashup platforms only support single-user scenarios, CRUISE enables the reconfiguration of multi-user mashups during runtime. Thereby, synchronizing different parts of an application based on black-box components from different vendors causes special challenges for the rights management system. Cause we additionally focus on non-programmers as target group, an adequate user interface concept is needed. To overcome these challenges, we present a triple-based rights management concept as well as a corresponding user interface support. It supports fine-grained sharing of whole applications, single components or UI parts of components under configurable permissions. Thereby, users can select semantically compatible components during the collaborative session. The practicability of our concept is validated by a prototypically implementation as well as a user acceptance test.

Private Data in Collaborative Web Mashups.

Situational development and utilization of long-tail Web applications often involves scenarios with multiple persons interacting. Keeping private data under control comes into focus when using applications in sensitive domains, such as financial management. Main problems comprise the lack of data restriction capabilities in an adequate granularity, missing awareness on data restricted as well as missing visual representations both on previewing such private data and replacement of non-shared data on the invitee’s side. To this end, we present an innovative sharing process with fine-grained control of private data, sharing awareness and impression management. Further, policy compliance for private data enables corporate use, fostering the utilization of the collaborative Web mashup paradigm in business application scenarios. A user study shows the suitability of the corresponding interaction features for the target group of Web users with no programming skills.

Fuzzy Mashup Quality Requirements Specification for Web Users

Up to now, specification and evaluation of quality requirements is neglected in current approaches for developing composite Web mashups. Important, yet missing concepts are quality requirements models and tool support for user-centered requirements specification. Therefore, it is cumbersome and unsatisfactorily for Web users, to express quality requirements on mash up components and select suitable ones for their self-made applications. In this paper, we present a novel approach of modelling quality requirements for composite Web mashups using colloquial terms, which augment a tailored property model. To this end, we introduce a quality requirements metamodel for Web mashups and show, how the mash up platform can meet the target groups skills and expectations by specifying quality requirements with fuzzy expressions. A user study underlines the benefit of employed modelling concepts and the implemented requirements composer, when performing common composition tasks.

Assisted End User Development for Non-programmers: Awareness, Exploration and Explanation of Composite Web Application Functionality.

Mashing up existing components allows end users to build custom web applications in order to fulfill situation-specific needs. However, creating and even using mashup applications still turn out to be complicated tasks for non-programmers. Main challenges include understanding the composite nature of mashups and their functionality. Non-programmers typically lack awareness for inter-widget communication and understanding of the functionality individual components and especially a set of combined components provide. Thus, they may struggle to use components as intended. Prevalent mashup approaches provide no or limited concepts and assistance tools in this regard, resulting in more or less successful trial and error strategies of users. In this paper, we introduce novel techniques for exploration, explanation and awareness of mashup functionality. These concepts assist non-programmers to better understand and to be aware of the capabilities that components and their interplay in a mashup provide. Based on annotated component descriptions, interactive explanations and stepwise tutorials are generated and presented directly in the components’ user interface. Additionally, mashup functionality can be explored and active inter-widget communication is visualized to foster awareness of non-programmers. We present our iterative design process which led us from early concepts towards our current solution. The proposed approach is validated with the help of a prototypical implementation within our mashup platform and evaluated by means of a user study. The results indicate that our concepts helps non-programmers to better understand and leverage the functionality of composite web applications.

Enabling End-Users to Individually Share Parts of Composite Web Applications

Support for collaborative work by software or web applications is well studied for years, but yet no approach exists which allow end-users with no or limited programming skills to build custom groupware applications for individual collaboration needs. Due to an increasing number of resources, APIs, and services within the web, creating new web applications nowadays can be simplified by just combining these atomic building blocks. Meanwhile, an increasing number of mashup platforms enable non-programmers to build situational web applications by their own by facilitating recommendation techniques and visual abstraction layers. But, none of these approaches cover sufficient support for multi-user scenarios. As one major foundation for collaboratively building and using composite web application (CWAs), we propose a triple-based permission management concept in line with a target group specific UI support. Thereby, users are empowered to share either applications, components or parts of them in the form of single application features or data. Additionally, previously selected private data can be excluded from being shared. We implemented the approach within our distributed runtime environment for CWAs and proved by two user studies that the basic concepts as well as the UI guidance work as expected.

Modeling and Calculating Capabilities of Composite Web Applications for Assisted End User Development

Based on an increasing number of web resources and services, the mashup paradigm enables end users to create custom web applications consisting of several components in order to fulfill specific needs. End user development of such composite web applications poses tough challenges to composition platforms, especially with non-programmers as end users. For instance, communicating on a non-technical level is crucial. Furthermore, assistance is essential throughout the entire process, ranging from composition to usage of mashups. Amongst others, users should be supported by explaining inter-widget communication, by helping to understand a mashup’s functionality and by identifying mashups providing desired functionality. However, prevalent mashup solutions provide no or limited concepts regarding these aspects. In this paper, we introduce our proposal for formalizing and calculating the functionality of mashup compositions based on capabilities and communication relations of mashup components as well as semantic domain knowledge. It serves as a foundation for our assisted, capability-centered end user development approach within the CRUISE platform. The latter features several assistance mechanisms, like presenting the functionality of mashups and recommending composition steps. We describe a prototypical implementation of the proposed algorithm and discuss its usage in our platform. Additionally, we evaluate our modeling and algorithmic concepts by means of example applications and an expert evaluation.