Nabil Layaïda | Institut National de Recherche en Informatique et Automatique (INRIA) (original) (raw)

Papers by Nabil Layaïda

In this paper, we discuss the effect of the uncertainty in the duration of some multimedia object... more In this paper, we discuss the effect of the uncertainty in the duration of some multimedia objects on the quality of the presentation of multimedia scenarios. This uncertainty can be due to external factors such as the access delay over internet or the user interaction. An uncertain duration is often followed by a period of desynchronization during which the presentation deviates from the desired scenario. To solve this problem, we present in this paper a solution that integrates two complementary approaches which reduce the desynchronization and limit its propagation in the rest of the presentation. These approaches are non-blocking and use the flexibility in the duration of multimedia objects in order to resynchronize the presentation as rapidly as possible.

Lecture Notes in Computer Science, 2004

In this paper we present a general framework for document production that covers generic document... more In this paper we present a general framework for document production that covers generic document model needs and adaptation needs. We define a multimedia document model called Madeus that describes multimedia scenarios. We show how this model is used for the generation of adaptable presentations. This presentation process is based on XSLT transformation techniques and constraint technologies for document formatting.

Proceedings of the sixth ACM international conference on Multimedia - MULTIMEDIA '98, 1998

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In this paper, we present our contribution to meet the main requirements for providing an authori... more In this paper, we present our contribution to meet the main requirements for providing an authoring environment for interactive multimedia documents. The particularity of our approach is to consider multimedia authoring as a whole, from speci cation issues to execution requirements. The results of these theoretical works are validated into a real running application called Madeus.

IEEE International Conference on Mobile Data Management, 2004. Proceedings. 2004, 2004

This paper discusses the problem of content adaptation for mobile devices. The adaptation conside... more This paper discusses the problem of content adaptation for mobile devices. The adaptation considers the context of the client and also the environment where the client request is received. A device independent model is defined and used in order to achieve automatic adaptation of the content based on its semantic and the capabilities of the target device. Our system includes a context description model and a client repository and offers device contexts management and querying functions. The proposed system uses the XQuery language to query the profiles and delivers the results in the form of SOAP services.

2003 Symposium on Applications and the Internet, 2003. Proceedings., 2003

In this paper, we present a framework which allows adapted content delivery for different target ... more In this paper, we present a framework which allows adapted content delivery for different target contexts. This framework is based on a Universal Profiling Schema UPS for describing the environment characteristics and on an profile exchange protocol. In the server and the proxy side, we give a strategy for matching the different constraints (clients, servers, content, etc.) in order to find an agreement between the server adaptation capabilities and the client preferences and constraints. Usually such environments are subject to frequent changes. To tackle this difficulty, we propose a dynamic adaptation approach based on XSLT for structural transformation and resource aware transcoders for the media adaptation.

Lecture Notes in Computer Science, 2004

Proceedings of the eleventh international conference on World Wide Web - WWW '02, 2002

In this paper, we present an incremental transformation framework called incXSLT. This framework ... more In this paper, we present an incremental transformation framework called incXSLT. This framework has been experimented for the XSLT language defined at the World Wide Web Consortium. For the currently available tools, designing the XML content and the transformation sheets is an inefficient, a tedious and an error prone experience. Incremental transformation processors such as incXSLT represent a better alternative

Proceedings of the 2007 international workshop on Semantically aware document processing and indexing - SADPI '07, 2007

The multiplication of presentation contexts (such as mobile phones, PDAs) for multimedia document... more The multiplication of presentation contexts (such as mobile phones, PDAs) for multimedia documents requires the adaptation of document specifications. In an earlier work, a semantic framework for multimedia document adaptation was proposed. This framework deals with the semantics of the document composition by transforming the relations between multimedia objects. However, it was lacking the capability of suppressing multimedia objects. In this paper, we extend the proposed adaptation with this capability. Thanks to this extension, we present a method for summarizing multimedia documents. Moreover, when multimedia objects are removed, the resulted document satisfies some properties such as presentation contiguity. To validate our framework, we adapt standard multimedia documents such as SMIL documents. Abstract {m} P oster {m,Abstract {m,mi,b,bi} y y t t t t t t t t t t t t t t t t t t t t {m,mi,b,bi} ) ) T railer Characters {m,Abstract R y y t t

Proceedings of the 2014 ACM symposium on Document engineering - DocEng '14, 2014

ABSTRACT Cascading Style Sheets (CSS) is a standard language for stylizing and formatting web doc... more ABSTRACT Cascading Style Sheets (CSS) is a standard language for stylizing and formatting web documents. Its role in web user experience becomes increasingly important. However, CSS files tend to be designed from a result-driven point of view, without much attention devoted to the CSS file structure as long as it produces the desired results. Furthermore, the rendering intended in the browser is often checked and debugged with a document instance. Style sheets normally apply to a set of documents, therefore modifications added while focusing on a particular instance might affect other documents of the set. We present a first prototype of static CSS semantical analyzer and optimizer that is capable of automatically detecting and removing redundant property declarations and rules. We build on earlier work on tree logics to locate redundancies due to the semantics of selectors and properties. Existing purely syntactic CSS optimizers might be used in conjunction with our tool, for performing complementary (and orthogonal) size reduction, toward the common goal of providing smaller and cleaner CSS files.

Proceedings of the 32nd ACM/IEEE International Conference on Software Engineering - ICSE '10, 2010

One of the challenges in web software development is to help achieving a good level of quality in... more One of the challenges in web software development is to help achieving a good level of quality in terms of code size and runtime performance, for increasingly popular domain specific languages such as XQuery. We present an IDE equipped with static analysis features for assisting the programmer. These features are capable of identifying and eliminating dead code automatically. The tool is based on newly developed formal programming language verification techniques , which are now mature enough to be introduced in the process of software development.

Proceedings of the 14th ACM SIGPLAN international conference on Functional programming - ICFP '09, 2009

During the life cycle of an XML application, both schemas and queries may change from one version... more During the life cycle of an XML application, both schemas and queries may change from one version to another. Schema evolutions may affect query results and potentially the validity of produced data. Nowadays, a challenge is to assess and accommodate the impact of these changes in evolving XML applications. Such questions arise naturally in XML static analyzers. These analyzers often rely on decision procedures such as inclusion between XML schemas, query containment and satisfiability. However, existing decision procedures cannot be used directly in this context. The reason is that they are unable to distinguish information related to the evolution from information corresponding to bugs. This paper proposes a predicate language within a logical framework that can be used to make this distinction. We present a system for monitoring the effect of schema evolutions on the set of admissible documents and on the results of queries. The system is very powerful in analyzing various scenarios where the result of a query may not be anymore what was expected. Specifically, the system is based on a set of predicates which allow a fine-grained analysis for a wide range of forward and backward compatibility issues. Moreover, the system can produce counterexamples and witness documents which are useful for debugging purposes. The current implementation has been tested with realistic use cases, where it allows identifying queries that must be reformulated in order to produce the expected results across successive schema versions.

Proceedings of the 21st international conference on World Wide Web - WWW '12, 2012

Proceedings of the 19th international conference on World wide web - WWW '10, 2010

We present a tool for helping XML schema designers to obtain a high quality level for their speci... more We present a tool for helping XML schema designers to obtain a high quality level for their specifications. The tool allows one to analyze relations between classes of XML documents and formally prove them. For instance, the tool can be used to check forward and backward compatibilities of recommendations. When such a relation does not hold, the tool allows one to identify the reasons and reports detailed counter-examples that exemplify the problem. For this purpose, the tool relies on recent advances in logic-based automated theorem proving techniques that allow for efficient reasoning on very large sets of XML documents. We believe this tool can be of great value for standardization bodies that define specifications using various XML type definition languages (such as W3C specifications), and are concerned with quality assurance for their normative recommendations.

2010 IEEE 26th International Conference on Data Engineering (ICDE 2010), 2010

We present a tool for the static analysis of XPath queries and XML Schemas. The tool introduces t... more We present a tool for the static analysis of XPath queries and XML Schemas. The tool introduces techniques used in the field of verification (such as binary decision diagrams) in order to efficiently solve XPath query satisfiability, containment, and equivalence, in the presence of real-world XML Schemas. The tool can be used in query optimizers, in order to prove soundness of query rewriting. It can also be used in type-checkers and optimizing compilers that need to perform all kinds of compile-time analyses involving XPath queries and XML tree constraints.

ACM SIGPLAN Notices, 2007

We present an algorithm to solve XPath decision problems under regular tree type constraints and ... more We present an algorithm to solve XPath decision problems under regular tree type constraints and show its use to statically typecheck XPath queries. To this end, we prove the decidability of a logic with converse for finite ordered trees whose time complexity is a simple exponential of the size of a formula. The logic corresponds to the alternation free modal µ-calculus without greatest fixpoint, restricted to finite trees, and where formulas are cycle-free.

Proceedings of IEEE International Conference on Multimedia Computing and Systems, 1997

We present Madeus, an authoring environment for interactive multimedia documents. Madeus 'aim can... more We present Madeus, an authoring environment for interactive multimedia documents. Madeus 'aim can be sumed up in the following statement : high temporal expressivity must not be reached to the detriment of a user-friendly interjace editing approach. We provide the author with a declarative and hierarchic speciJication language based on an extension of Allen's algebra. Static temporal checking and dynamic scheduling are based on an extension of temporal constraint networks.

Proceedings of the 2006 ACM symposium on Document engineering - DocEng '06, 2006

XPath is the standard declarative language for navigating XML data and returning a set of matchin... more XPath is the standard declarative language for navigating XML data and returning a set of matching nodes. In the context of XSLT/XQuery analysis, query optimization, and XML type checking, XPath decision problems arise naturally. They notably include XPath comparisons such as equivalence (whether two queries always return the same result), and containment (whether for any tree the result of a