Joel André Ferreira dos Santos

XTemplate 3.0: spatio-temporal semantics and structure reuse for hypermedia compositions

The use of declarative languages in digital TV systems, as well as IPTV systems, facilitates the creation of interactive applications. However, when an application becomes more complex, with many user interactions, for example, the hypermedia document that describes that application becomes bigger, having many lines of XML code. Thus, specification reuse is crucial for an efficient application development process. This paper proposes the XTemplate 3.0 language, which allows the creation of NCL hypermedia composite templates. Templates define generic structures of nodes and links to be added to a document composition, providing spatio-temporal synchronization semantics to it. The use of hypermedia composite templates aims at facilitating the authoring work, allowing the reuse of hypermedia document common specifications. Using composite templates, hypermedia documents become simpler and easier to be created. The 3.0 version of XTemplate adds new facilities to the XTemplate language, such as the possibility of specifying presentation information, the attribution of values to variables and connector parameters during template processing time and the template ability to extend other templates. As an application of XTemplate, this work extends the NCL 3.0 declarative language with XTemplate, adding semantics to NCL contexts and providing document structure reuse. In addition, this paper also presents two authoring tools: the template processor and the wizard to create NCL documents using templates. The wizard tool allows the author to choose a template included in a template base and create an NCL document using that template. The template processor transforms an NCL document using templates into a standard NCL 3.0 document according to digital TV and IPTV standards.

NCL4WEB: translating NCL applications to HTML5 web pages

Testing Digital TV applications is not a simple task. DTV applications either need to be transmitted by a TV broadcaster or someone with an equipment capable of generating a DTV signal with the application embedded. Alternatively, an interactive TV application developer may use a virtual execution environment, like a virtual set-top box installed in a computer, which implements the digital TV middleware standard. In both cases, the application usually does not reach a large number of final users, and developers may not be motivated to continue working with digital TV interactive content. On the other hand, HTML5 support for multimedia content will certainly attract multimedia authors to web development. Considering this scenario, this work proposes an alternative way of presenting a digital TV application developed in NCL for the Ginga declarative middleware, translating it into HTML5 web pages, so it can be presented using a common web browser. The translation tool is called NCL4WEB. Like HTML, NCL is XML-based, so NCL4WEB is based on XSLT stylesheets. It transforms NCL elements into HTML5 elements and a set of JavaScript functions that implement synchronization relationships among media objects, including user interaction. Using NCL4WEB, NCL developers are able to publish their interactive TV applications on the web. It is transparent for final users to access HTML5 or NCL content using a web browser.

EDITEC: hypermedia composite template graphical editor for interactive tv authoring

This paper presents EDITEC, a graphical editor for hypermedia composite templates that can be used for authoring interactive TV programs. EDITEC templates are based on the XTemplate 3.0 language. EDITEC was designed for offering a user-friendly visual graphical approach. It provides several options for representing iteration structures and a graphical interface for creating basic XPath expressions. The editor provides a multiple-view environment, giving the user a complete control of the composite template during the authoring process. Composite templates can be used in NCL programs for embedding spatio-temporal semantics into NCL contexts. NCL is the standard declarative language used for the production of interactive applications in the Brazilian digital TV system and ITU H.761 IPTV services.

XTemplate 3.0: adding semantics to hypermedia compositions and providing document structure reuse

Hypermedia composite templates define generic structures of nodes and links that can be reused in different document compositions. The XTemplate language is an XML-based solution for defining composite templates for hypermedia documents in order to embed semantics into a composition that does not have it in prior. The use of templates intend to facilitate the authoring of interactive applications in Digital TV systems, as long as IPTV systems. XTemplate 3.0 extends the previous XTemplate versions, incorporating new features to the language and increasing its expressiveness. As an application of XTemplate, this work extends NCL (Nested Context Language) with XTemplate, adding semantics to NCL contexts and providing document structure reuse.

Spatio-temporal Validation of Multimedia Documents

A multimedia document authoring system should provide analysis and validation tools that help authors find and correct mistakes before document deployment. Although very useful, multimedia validation tools are not often provided. Spatial validation of multimedia documents may be performed over the initial position of media items before presentation starts. However, such an approach does not lead to ideal results when media item placement changes over time. Some document authoring languages allow the definition of spatio-temporal relationships among media items and they can be moved or resized during runtime. Current validation approaches do not verify dynamic spatio-temporal relationships. This paper presents a novel approach for spatio-temporal validation of multimedia documents. We model the document state, extending the Simple Hypermedia Model (SHM), comprising media item positioning during the whole document presentation. Mapping between document states represent time lapse or user interaction. We also define a set of atomic formulas upon which the authors expectations related to the spatio-temporal layout can be described and analyzed.

Automating the analysis of NCL documents with a model-driven approach

This paper presents a model-driven approach for the analysis of NCL documents. Structural and behavioral properties of NCL documents are verified guaranteeing its well-formedness and conformance with respect to the NCL language semantics. Document structural properties are verified using invariant validation and document behavioral properties are verified through model checking. The model-driven approach proposed is based on a formal and simplified model for representing the NCL document presentation behavior called Simple Hypermedia Model (SHM), used for the verification of document properties. In addition, this paper presents a prototype implementation of the proposed approach.

Adaptive layouts for authoring NCL programs

This paper presents a layout module that incorporates the facility of specifying adaptive spatial layouts, providing automatic creation of regions and descriptors for NCL documents. Two types of adaptive spatial layouts are provided: flowLayout and gridLayout. Adaptive layouts are very useful for defining generic templates for hypermedia documents, where the number of components will be specified by the final NCL application. Therefore this proposal facilitates the authoring of hypermedia documents used for interactive content creation in the Brazilian Digital TV System.

Modeling sensory effects as first-class entities in multimedia applications

Multimedia applications are usually composed by audiovisual content. Traditional multimedia conceptual models, and consequently declarative multimedia authoring languages, do not support the definition of multiple sensory effects. Multiple sensorial media (mulsemedia) applications consider the use of sensory effects that can stimulate touch, smell and taste, in addition to hearing and sight. Therefore, mulsemedia applications have been usually developed using general-purpose programming languages. In order to fill in this gap, this paper proposes an approach for modeling sensory effects as first-class entities, enabling multimedia applications to synchronize sensorial media to interactive audiovisual content in a high-level specification. Thus, complete descriptions of mulsemedia applications will be made possible with multimedia models and languages. In order to validate our ideas, an interactive mulsemedia application example is presented and specified with NCL (Nested Context Language) and Lua. Lua components are used for translating sensory effect high-level attributes to MPEG-V SEM (Sensory Effect Metadata) files. A sensory effect simulator was developed to receive SEM files and simulate mulsemedia application rendering.

A rewriting logic semantics for NCL

The Nested Context Language (NCL) is a multimedia authoring language that is part of the standard for digital television in Brazil and in Latin America and the ITU standard for IPTV services. To properly support authors in the development of NCL applications, it is important to provide tools with validation capabilities. The validation of multimedia documents indicates to the author possible inconsistent points in a given document. Thus the author has the possibility of correcting those inconsistencies before making the multimedia document available for the final user. The validation approach presented in this work considers a set of desirable document properties based on related work published in the literature. Since NCL applications may be understood as finite transition systems, standard model-based validation techniques directly apply. This paper discusses a formalization of NCL semantics with rewriting theory. Two theories are given to represent (i) NCLs static semantics and (ii) NCLs dynamic semantics. In the former, NCL structural properties are validated through equational reduction, while in the latter, NCL expected behaviors are validated through searching.

JNS: An alternative authoring language for specifying NCL multimedia documents

This paper presents JNS - JSON NCL Script, a declarative authoring language for describing NCL multimedia documents. NCL (Nested Context Language) is a standard language used in the Brazilian Digital Television System and in the ITU H.761 IPTV services recommendation for specifying interactive multimedia applications. Once NCL is XML-based, even simple NCL documents have several lines of code. JNS provides a new way of writing an NCL document, offering a more compact textual representation and providing more expressiveness to NCL. JNS is based on the Java Script Object Notation (JSON) instead of the XML standard. This work presents an overview of the JNS language and the new functionalities it brings to NCL document specification. In addition, comparisons between JNS and NCL specifications are shown.