Model-driven development of composite context-aware web applications

Context-awareness constitutes an essential aspect of services, especially when interaction with end-users is involved. In this paper a solution for the context-aware development of web applications consisting of web services is presented. The methodology proposes a model based approach and advocates in favour of a complete separation of the web application functionality from the context adaptation at all development phases (analysis, design, implementation). In essence, context adaptation takes place on top of and is transparent to the web application business functionality. Starting from UML diagrams of independent web services and respective UML context models, our approach can produce a functional composite context-aware application. At execution level this independence is maintained through an adaptation framework based on message interception.     

H: A component-based specification language for heterogeneous applications

This paper presents H, a minimalistic specification language for designing heterogeneous software applications, particularly in the realms of robotics and industria, which takes advantage of a Component-Based Software Engineering (CBSE) approach. H copes with some of the most outstanding characteristics of these systems, like diversity at different levels (hardware platforms, programming languages, programmer skills), network distribution, real time and fault-tolerance. The H specification covers the life-cycle of any heterogeneous application. Its development system offers to the designer and/or builder a set of tools for specifying modules, generating code semiautomatically, debugging, maintenance, and a real time analysis of the system.     

AML: a modeling language for designing adaptive web applications

Modern WWW methodologies focus on developing context-aware data delivery applications on the Web, but very few proposals provide a conceptual modeling of their adaptation specifications. In this paper, we present AML—Adaptation Modeling Language—to specify complex Adaptive Web Applications at the conceptual level. AML models the adaptation process by using a special workflow involving modeling primitives that execute elementary manipulations. The adaptation considers different and orthogonal components of the context and operates over the selection of the most suitable contents, the organization of the hypertext structure of the response, and the layout of the final pages. The language and its design process are fully implemented in a CASE tool, called FAWIS. Specifically, FAWIS is able to access a Web data source and automatically filter and adapt information delivery on the basis of the context of the client. The tool is able to manage heterogeneous contexts, is easy extensible to new coordinates of adaptation, and can integrate different adaptation requirements solving possible conflicts between them. It allows the designer to define the response that better satisfies the requirements of adaptation for a context.     

MIMOSA: context-aware adaptation for ubiquitous web access

The ubiquitous computing scenario is characterized by heterogeneity of devices used to access services, and by frequent changes in the user’s context. Hence, adaptation according to the user’s context and the used devices is necessary to allow mobile users to efficiently exploit Internet-based services. In this paper, we present a distributed framework, named MIMOSA, that couples a middleware for context-awareness with an intermediary-based architecture for content adaptation. MIMOSA provides an effective and efficient solution for the adaptation of Internet services on the basis of a comprehensive notion of context, by means of techniques for aggregating context data from distributed sources, deriving complex contextual situations from raw sensor data, evaluating adaptation policies, and solving possible conflicts. The middleware allows programmers to modularly build complex adaptive services starting from simple ones, and includes tools for assisting the user in declaring her preferences, as well as mechanisms for detecting incorrect system behaviors due to a wrong choice of adaptation policies. The effectiveness and efficiency of MIMOSA are shown through the development of a prototype adaptive service, and by extensive experimental evaluations.     

Adapting web pages using graph partitioning algorithms for user-centric multi-device web browsing

In the era of ubiquitous computing, applications are emerging to benefit from using devices of different users and different capabilities together. This paper focuses on user-centric web browsing using multiple devices, where content of a web page is partitioned, adapted and allocated to devices in the vicinity. We contribute two novel web page partitioning algorithms. They differ from existing approaches by allowing for both, automatic and semi-automatic partitioning. On the one hand, this provides good automatic, web page independent results by utilizing sophisticated structural pre- and postprocessing of the web page. On the other hand, these results can be improved by considering additional semantic information provided through user-generated web page annotations. We further present a performance evaluation of our algorithms. Moreover, we contribute the results of a user study. These clearly show that (1) our algorithms provide good automatic results and (2) the application of user-centric, annotation-based semantic information leads to a significantly higher user satisfaction.     

Framework for context-aware smartphone applications

This paper presents research and development of a dedicated system architecture, designed to enable its users to interact with each other as well as to access information on points of interest that exist in their immediate environment. This is accomplished through managing personal preferences and contextual information in a distributed manner and in real time. The advantage of this system is that it uses mobile devices, heterogeneous sensors and a selection of user interface paradigms to produce a sociotechnical framework to enhance the perception of the environment and promote intuitive interactions. Representation of the real-world objects, their spatial relations and other captured features are visualised on scalable interfaces, ranging from 2D to 3D models and from photorealism to stylised clues and symbols. The conceptual design and implementation of our location and orientation based algorithm for mobile augmented reality is presented in detail. The framework is fit for use in unknown environments and therefore suitable for ubiquitous operation. The presented prototype is multifaceted and capable of supporting peer-to-peer exchange of information in a pervasive fashion, usable in various contexts. The modalities of these interactions are explored and laid out particularly in the context of entertainment and urban navigation.     

Web应用的UML协作图建模与形式化规格说明

针对Web应用的特点,从整体功能层面和交互行为层面用UML协作图构建了Web应用模型,以便精确、有效地描述参与协作对象间的结构关系和交互行为,保证在利用UML形式的规格说明推导测试用例时所需的语义信息.研究了运用Object-Z语言来形式化描述Web应用模型,提出了相应的转换规则.设计了形式化规格说明自动化生成的工具(UMLTOZ)中的主要相关类库.     

A JESS-enabled context elicitation system for providing context-aware Web services

Providing context-aware Web services is an adaptive process of delivering contextually matched Web services to meet service requesters’ needs. We define the term “context” from two perspectives: one from service requesters; and the other from Web services. From the former perspective, context is defined as the surrounding environment affecting requesters’ services discovery and access, such as requesters’ preferences, locations, activities, and accessible network and devices. From the latter perspective, context is defined as the surrounding environment affecting Web services delivery and execution, such as networks and protocols for service binding, devices and platforms for service execution, and so on. This paper presents a Java Expert System Shell (JESS)-enabled context elicitation system featuring an ontology-based context model that formally describes and acquires contextual information pertaining to service requesters and Web services. Based on the context elicitation system, we present a context-aware services-oriented architecture for providing context-aware Web service request, publication, and discovery. Implementation details of the context elicitation system and the evaluation results of context-aware service provision are also reported.     

觉察上下文的Web服务研究与应用

现有的Web服务框架不能适应普适计算的特点,即无法为移动用户提供自定义的个性化的服务.通过对现有Web服务的扩展,提出了一个觉察上下文的自适应的Web服务开发与部署框架.在该框架中,客户端的上下文信息作为SOAP消息的头块被分布式地传递和处理,Web服务可为客户端提供自定义的个性化的服务.同时,上下文是可扩展的,通过自动的上下文处理,Web服务可自适应新的上下文而不需要改变Web服务本身.     

ContextPhone: a prototyping platform for context-aware mobile applications

Smart phones are a particularly tempting platform for building context-aware applications because they're programmable and often use well-known operating systems. There's a gap, however, between the operating systems' functionality and the features that application developers need. To fill this gap, we've designed and developed ContextPhone, a software platform consisting of four interconnected modules provided as a set of open source C++ libraries and source code components. ContextPhone runs on off-the-shelf mobile phones using Symbian OS and the Nokia Series 60 Smartphone platform. ContextPhone was developed using an iterative, human-centered design strategy. It thus helps developers more easily create applications that integrate into both existing technologies and users' everyday lives.     

CARISMA: context-aware reflective middleware system for mobile applications

Mobile devices, such as mobile phones and personal digital assistants, have gained wide-spread popularity. These devices will increasingly be networked, thus enabling the construction of distributed applications that have to adapt to changes in context, such as variations in network bandwidth, battery power, connectivity, reachability of services and hosts, etc. In this paper, we describe CARISMA, a mobile computing middleware which exploits the principle of reflection to enhance the construction of adaptive and context-aware mobile applications. The middleware provides software engineers with primitives to describe how context changes should be handled using policies. These policies may conflict. We classify the different types of conflicts that may arise in mobile computing and argue that conflicts cannot be resolved statically at the time applications are designed, but, rather, need to be resolved at execution time. We demonstrate a method by which policy conflicts can be handled; this method uses a microeconomic approach that relies on a particular type of sealed-bid auction. We describe how this method is implemented in the CARISMA middleware architecture and sketch a distributed context-aware application for mobile devices to illustrate how the method works in practice. We show, by way of a systematic performance evaluation, that conflict resolution does not imply undue overheads, before comparing our research to related work and concluding the paper.     

WebSpec: a visual language for specifying interaction and navigation requirements in web applications

Web application development is a complex and time-consuming process that involves different stakeholders (ranging from customers to developers); these applications have some unique characteristics like navigational access to information, sophisticated interaction features, etc. However, there have been few proposals to represent those requirements that are specific to Web applications. Consequently, validation of requirements (e.g., in acceptance tests) is usually informal and as a result troublesome. To overcome these problems, we present WebSpec, a domain-specific language for specifying the most relevant and characteristic requirements of Web applications: those involving interaction and navigation. We describe WebSpec diagrams, discussing their abstraction and expressive power. With a simple though realistic example, we show how we have used WebSpec in the context of an agile Web development approach discussing several issues such as automatic test generation, management of changes in requirements, and improving the understanding of the diagrams through application simulation.     

Accessible user interface support for multi-device ubiquitous applications: architectural modifiability considerations

The market for personal computing devices is rapidly expanding from PC, to mobile, home entertainment systems, and even the automotive industry. When developing software targeting such ubiquitous devices, the balance between development costs and market coverage has turned out to be a challenging issue. With the rise of Web technology and the Internet of things, ubiquitous applications have become a reality. Nonetheless, the diversity of presentation and interaction modalities still drastically limit the number of targetable devices and the accessibility toward end users. This paper presents webinos, a multi-device application middleware platform founded on the Future Internet infrastructure. Hereto, the platform’s architectural modifiability considerations are described and evaluated as a generic enabler for supporting applications, which are executed in ubiquitous computing environments.     

Towards a programming model for context-aware applications

In mobile computing scenarios, users move in different environments and applications can automatically explore their surroundings. This type of context-aware application is an emerging trend, so far not widely disseminated. We believe that the proposal of a programming model specifically designed for the specification of context-aware applications, using general abstractions, will foster a rapidly widespread of such kind of software. In this article, we propose the use of the Holoparadigm (in short Holo) to fill this gap. We created a programming language based on Holo (called HoloL) to demonstrate the strengths of Holoparadigm to develop context-aware applications. The article uses a sample scenario to show the Holo's practical aspects related to implementation of context-aware applications. We also present a platform to HoloL (called HoloEnv), composed of a compiler, a virtual machine, and a distributed execution environment. Finally, different performance aspects of the HoloEnv's components were evaluated through experimental results.     

An adaptive middleware framework for context-aware applications

We describe a middleware framework for the adaptive delivery of context information to context-aware applications. The framework abstracts the applications from the sensors that provide context. Further applications define utility functions on the quality of context attributes that describe the context providers. Then, given multiple alternatives for providing the same type of context, the middleware applies the utility function to each alternative and choose the one with maximum utility. By allowing applications to delegate the selection of context source to the middleware, our middleware can implement autonomic properties, such as self-configuration when new context providers appear and resilience to failures of context providers.

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Modechart: a specification language for real-time systems

Present a specification language for real-time systems called Modechart. The semantics of Modechart is given in terms of real-time logic (RTL), which is especially amenable to reasoning about the absolute (real-time clock) timing of events. The semantics of Modechart has an important property that the translation of a Modechart specification into RTL formulas results in a hierarchical organization of the resulting RTL assertions. This gives us significant leverage in reasoning about properties of a system by allowing us to filter out assertions that concern lower levels of abstraction. Some results about desirable properties of Modechart specifications are given. A graphical implementation of Modechart has been completed     

Spectra: a specification language for reactive systems

We introduce Spectra, a new specification language for reactive systems, specifically tailored for the context of reactive synthesis. The meaning of Spectra is defined by a translation to a kernel language. Spectra comes with the Spectra Tools, a set of analyses, including a synthesizer to obtain a correct-by-construction implementation, several means for executing the resulting controller, and additional analyses aimed at helping engineers write higher-quality specifications. We present the language in detail and give an overview of its tool set. Together with the language and its tool set, we present four collections of many, non-trivial, large specifications, written by undergraduate computer science students for the development of autonomous Lego robots and additional example reactive systems. The collected specifications can serve as benchmarks for future studies on reactive synthesis. We present the specifications, with observations and lessons learned about the potential use of reactive synthesis by software engineers.