We present an XML format that allows to describe a large class of finite weighted automata and transducers. Our design choices stem from our policy of making the implementation as simple as possible. This format has been tested for the communication between the modules of our automata manipulation platform Vaucanson, but this document is less an experiment report than a position paper intended to open the discussion among the community of automata software writers.

In this paper, we describe systems that were developed for the Open Performance Sub-Challenge of the INTERSPEECH 2009 Emotion Challenge. We participate to both two-class and five-class emotion detection. For the two-class problem, the best performance is obtained by logistic regression fusion of three systems. Theses systems use short- and long-term speech features. This fusion achieved an absolute improvement of 2,6% on the unweighted recall value compared with [6]. For the five-class problem, we submitted two individual systems: cepstral GMM vs. long-term GMM-UBM. The best result comes from a cepstral GMM and produced an absolute improvement of 3,5% compared to [6].

Shared decision diagram representations of a state-space provide efficient solutions for model-checking of large systems. However, decision diagram manipulation is tricky, as the construction procedure is liable to produce intractable intermediate structures (a.k.a peak effect). The definition of the so-called saturation method has empirically been shown to mostly avoid this peak effect, and allows verification of much larger systems. However, applying this algorithm currently requires deep knowledge of the decision diagram data-structures. Hierarchical Set Decision Diagrams (SDD) are decision diagrams in which arcs of the structure are labeled with sets, themselves stored as SDD. This data structure offers an elegant and very efficient way of encoding structured specifications using decision diagram technology. It also offers, through the concept of inductive homomorphisms, flexibility to a user defining a transition relation. We show in this paper how, with very limited user input, the SDD library is able to optimize evaluation of a transition relation to produce a saturation effect at runtime. We build as an example an SDD model-checker for a compositional formalism: Instantiable Petri Nets (IPN). IPN define a <i>type</i> as an abstract contract. Labeled P/T nets are used as an elementary type. A composite type is defined to hierarchically contain instances (of elementary or composite type). To compose behaviors, IPN use classic label synchronization semantics from process calculi. With a particular recursive folding SDD are able to offer solutions for symmetric systems in logarithmic complexity with respect to other DD. Even in less regular cases, the use of hierarchy in the specification is shown to be well supported by SDD. Experimentations and performances are reported on some well known examples.

We present a programming framework for discrete mathematical morphology centered on the concept of genericity. We show that formal definitions of morphological algorithms can be translated into actual code, usable on virtually any kind of compatible images, provided a general definition of the concept of image is given. This work is implemented in Milena, a generic, efficient, and user-friendly image processing library.

This article presents several techniques to combine between Support vector machines (SVM) and Joint Factor Analysis (JFA) model for speaker verification. In this combination, the SVMs are applied on different sources of information produced by the JFA. These informations are the Gaussian Mixture Model supervectors and speakers and Common factors. We found that the use of JFA factors gave the best results especially when within class covariance normalization method is applied in the speaker factors space, in order to compensate for the channel effect. The new combination results are comparable to other classical JFA scoring techniques.

ASTs are commonly used to represent an input/output program in compilers and language processing tools. Many of the tasks of these tools consist in generating and rewriting ASTs. Such an approach can become tedious and hard to maintain for complex operations, namely program transformation, optimization, instrumentation, etc. On the other hand, <i>concrete syntax</i> provides a natural and simpler representation of programs, but it is not usually available as a direct feature of the aforementioned tools. We propose a simple technique to implement AST generation and rewriting in general purpose languages using concrete syntax. Our approach relies on extensions made in the scanner and the parser and the use of objects supporting partial parsing called Text With Embedded Abstract Syntax Trees (TWEASTS). A compiler for a simple language (Tiger) written in serves as an example, featuring transformations in concrete syntax: syntactic desugaring, optimization, code instrumentation such as bounds-checking, etc. Extensions of this technique to provide a full-fledged concrete-syntax rewriting framework are presented as well.

This article reports the results of an ongoing experimental research on the behavior and performance of CLOS, the Common Lisp Object System. Our purpose is to evaluate the behavior and performance of the 3 most important characteristics of any dynamic Object Oriented system: class instantiation, slot access and dynamic dispatch. This paper describes the results of our experiments on instantiation. We evaluate the efficiency of the instantiation process in both C++ and Lisp under a combination of parameters such as slot types or classes hierarchy. We show that in a non-optimized configuration where safety is given priority on speed, the behavior of C++ and Lisp instantiation can be quite different, which is also the case amongst different Lisp compilers. On the other hand, we demonstrate that when compilation is tuned for speed, instantiation in Lisp becomes faster than in C++.

Implementing binary methods in traditional object-oriented languages is difficult: numerous problems arise regarding the relationship between types and classes in the context of inheritance, or the need for privileged access to the internal representation of objects. Most of these problems occur in the context of statically typed languages that lack multi-methods (polymorphism on multiple arguments). The purpose of this paper is twofold: first, we show why some of these problems are either non-issues, or easily solved in Common Lisp. Then, we demonstrate how the Common Lisp Object System (CLOS) allows us not only to implement binary methods in a straightforward way, but also to support the concept directly, and even enforce it at different levels (usage and implementation).

Compiler construction, a course feared by most students, and a competence seldom needed in the industry. Yet we claim that compiler construction is wonderful topic that benefits from virtually all the computer-science topics. In this paper we show in particular why compiler construction is a killer example for Object-Oriented Programming, providing a unique opportunity for students to understand what it is, what it can be used for, and how it works.