We examine the ML pattern-matching anomalies of useless clauses and non-exhaustive matches. We state the definition of these anomalies, building upon pattern matching semantics, and propose a simple algorithm to detect them. We have integrated the algorithm in the Objective Caml compiler, but we show that the same algorithm is also usable in a non-strict language such as Haskell. Or-patterns are considered for both strict and non-strict languages.

This paper addresses problems to achieve transparency and contact stability for teleoperation that consists of unconstrained and constrained motions. The adaptive bilateral control with a local force compensator is developed, based on adaptive impedance control and contact force driven compensation with auto-switching functions. Without any knowledge about robotic and environment dynamics and with a communication delay, the developed method guarantees good adaptive tracking performance in unconstrained motion and reduction of oscillating contacts in constrained motion. Based on an actual haptic device and a virtual manipulator, haptic simulations are presented to demonstrate adaptive transparency and contact stability in the presence of communication delay.

This paper addresses the views of students of blended language learning (BLL) – a particular learning and teaching environment, that combines face-to-face (f2f) and computer-assisted language learning (CALL). In this instance, the ‘blend’ consisted of learners’ independent self-study phases at a computer, with a CD-ROM, and traditional f2f classroom learning. This paper explores this BLL environment from the participants’ perspective and focuses on three learners who left the class. The aim of the study was to understand the reasons behind those students’ decision to leave, so that ideas might be developed for the successful implementation of BLL environments in the future that would appeal to all learners. The analysis showed that students left the class for three reasons: a perceived lack of support and connection/complementarity between the f2f and computer-assisted components of the ‘blend’; a perceived lack of usage of the paper medium for reading and writing; and the rejection of the computer as a medium of language learning. The paper concludes by pointing out implications for the possible future of BLL.

We present two case studies of two different pedagogical tasks in a Computer Assisted Language Learning environment called Grim. The main design principle in Grim is to support ‘Focus on Form’ in second language pedagogy. Grim contains several language technology-based features for exploring linguistic forms (static, rule-based and statistical), intended to be used while writing. Our question is, in what ways does Grim support Focus on Form in actual classroom use. We have explored this question within sociocultural theory, emphasizing tool mediation and how tools shape the learner’s activity. The first case concerns a text-reconstruction exercise in which students worked in a pair within the Grim environment. The second case was conducted with another group of students, who engaged in collaborative revision of texts, written in advance by one of the students, in student pairs. In both studies, students were instructed and encouraged to use the different features of Grim. Data was collected by recording dialogue during the sessions with Grim. Our results show how learners put the features of Grim into use in their writing tasks. In some instances, the program was used creatively, in combination with external tools such as the users’ own dictionaries, knowledge of other languages, or teachers. In other instances, we note that Grim was used for error correction, rather than as a language resource. The learners’ activities are thus transformed by their use of the program, from the tasks of revision and text-reconstruction into error correction. The application shapes the activity, in conjunction with the pedagogical tasks. We argue for studying the activities of students with CALL tools, in order to find out in detail how tasks and technology concur in use and what view on language and pedagogy they mediate.

English as a Second Language (ESL) teachers in Malaysia, as in many other countries, are anxious to exploit the potential of Information and Communication Technologies (ICT) to enhance the teaching and learning process. Given the increasing pressure exerted by technological developments on language education, it is important to understand the underlying factors behind teachers’ decisions regarding ICT. Egbert et al. (2002) state that few investigations have been conducted on computer-using language teachers’ development. According to BECTA (1999) the learning potential of ICT is not being realised, because many teachers are not familiar with ICT and do not use it in their teaching. This study investigates the present use of ICT among ESL technical school teachers in teaching, factors that affect the use of ICT and perceptions of their skills in ICT. The theory that frames this study is drawn from theories of learning. The model adopted is Davis’ Technology Acceptance Model (TAM) (1989) which provides a basis for determining ICT attitudes and factors affecting the usage of ICT in teaching. Data was collected via a questionnaire survey of ESL technical school teachers in Malaysia, and followed by semi-structured interviews with them. The questionnaire data was analysed using descriptive statistics and later triangulated with the interviews. The findings will be presented and elaborated upon in this paper.

This case study investigated the ways pre-major and pre-minor students of Spanish interacted with a grammar application from four perspectives. Firstly, using the computer’s tracking ability to collect learners’ behaviors, the study set out to uncover the different ways learners approached the application. Secondly, the study assessed the influence of two learner variables on learning behaviors: language abilities determined by a placement test and personality preferences measured by Jung-Myers-Briggs-Typology based approach. Thirdly, the study assessed whether the frequency of various behaviors resulted in different knowledge increases. Finally, the study categorized the uncovered behaviors into the learning strategies covered in the Strategy Inventory for Language Learning (SILL) (Oxford 1990). The study concludes with implications for software improvement, as well as with indications of likely directions for future research.

If some readers are surprised to receive a copy of ReCALL at this early stage in the year,let me remind you that we are now moving from two to three issues a year, for publication in January, May and September instead of May and November. The changeover has proved rather difficult, in terms of allowing time for authors to make revisions in the light of reviewers’ comments, which is why this issue is rather late.

In this issue, as well as regular papers from Dermot Campbell, Fenfang Hwu and Elke Stracke, we have included two papers from the EUROCALL 2006 conference in Granada. Melor Md Yunus discusses Malaysian ESL Teachers’ Use of ICT in Their Classrooms, whilst Petter Karlström and colleagues explore Tool mediation in focus-on-form activities. Having received 39 conference paper submissions, so far 13 have been rejected (but some of these have been advised to submit a version of their paper to the EUROCALL Review) and the remainder are at various stages in the process of bringing them to publication. Tony Harris, organiser of the Granada conference, will have more to say about conference submissions in the next issue of ReCALL, where the bulk of the selected papers will be published.

This paper outlines the ongoing construction of a speech corpus for use by applied linguists and advanced EFL/ESL students. In the first part, sections 1–4, the need for improvements in the teaching of listening skills and pronunciation practice for EFL/ESL students is noted. It is argued that the use of authentic native-to-native speech is imperative in the teaching/learning process so as to promote social inclusion. The arguments for authentic language learning material and the use of a speech corpus are contextualised within the literature, based mainly on the work of Swan, Brown and McCarthy. The second part, section 5, addresses features of native speech flow which cause difficulties for EFL/ESL students (Brown, Cauldwell) and establishes the need for improvements in the teaching of listening skills. Examples are given of reduced forms characteristic of relaxed native speech, and how these can be made accessible for study using the Dublin Institute of Technology’s slow-down technology, which gives students more time to study native speech features, without tonal distortion. The final part, sections 6–8, introduces a novel Speech Corpus being developed at DIT. It shows the limits of traditional corpora and outlines the general requirements of a Speech Corpus. This tool – which will satisfy the needs of teachers, learners and researchers – will link digitally recorded, natural, native-to-native speech so that each transcript segment will give access to its associated sound file. Users will be able to locate desired speech strings, play, compare and contrast them – and slow them down for more detailed study.

In this paper, a Neural-Network- (NN) based guidance methodology is proposed for the high-precision docking of autonomous vehicles/platforms. The novelty of the overall online motion-planning methodology is its applicability to cases that do not allow for the direct proximity measurement of the vehicle's pose (position and orientation). In such instances, a guidance technique that utilizes Line-of-Sight- (LOS) based task-space sensory feedback is needed to minimize the detrimental impact of accumulated systematic motion errors. Herein, the proposed NN-based guidance methodology is implemented during the final stage of the vehicle's motion (i.e., docking). Systematic motion errors, which are accumulated after a long-range motion are reduced iteratively by executing corrective motion commands generated by the NN until the vehicle achieves its desired pose within random noise limits. The proposed guidance methodology was successfully tested via simulations for a 6-dof (degree-of-freedom) vehicle and via experiments for a 3-dof high-precision planar platform.

To obtain specifications for a tactile display that would be effective in virtual reality and tele-existence systems, we have developed two types of matrix-type experimental tactile displays. One is for virtual figures (display A) and the other is for virtual textures (display B). Display A's pad has a 4 × 6 array of stimulus pins, each 0.8 mm in diameter. Three pad configurations, in which distances between any two adjacent pins (pin pitch) are 1.2, 1.9, or 2.5 mm, were developed to examine the influence of distance on a human operator's determination of virtual figures. Display B has an 8 × 8 array of stimulus pins, each 0.3 mm in diameter and with 1-or 1.8-mm pin pitch, because presentation of virtual textures was presumed to require a higher pin density. To establish a design method for these matrix-type tactile displays, we performed a series of psychophysical experiments using displays A and B. By evaluating variations in the correct answer percentage and threshold caused by different pin arrays and different pin strokes, we determined under what conditions the operator could best feel the virtual figures and textures. The results revealed that the two-point threshold should be adopted as the pitch between pins in the design of the tactile display, that a pin stroke should exceed 0.25 mm, and that the adjustment method is the most appropriate to evaluate the capabilities of tactile displays. Finally, when we compared the virtual texture with the real texture, we found that the threshold for the real texture is almost 1/3rd that of the virtual texture. This result implies that it is effective to present variations in patterns caused by rotation and variation in shearing force, itself produced by relative motion between the finger surface and object surface.

Up to now, most people are still cooking in the kitchen, which makes them feel fatigued and also makes the air polluted. With the development of the numerical control technology, it becomes more and more urgent to apply the related technology to the automatic cooking field. In this paper, the cooking technique for the Chinese dishes is introduced and China's first cooking robot, named AI Cooking Robot (AIC), is presented. The robot mainly consists of four parts: the wok mechanism, the stirring-fry and dispersing mechanism, the feeding mechanism, and the mechanism of leaving the material in the middle process. In order to adjust the temperature, the fire control system is also given in this paper. Experiments show that the new robot will be a milestone in the cooking automation science because of its cooking technique.

This paper describes the development of a novel compact magneto-rheological (MR) fluid brake with high transmitted torque and a simple structure. The MR fluid brake has two shearing disks with an electromagnetic coil located between them. Such a structure enables the brake to have a small radial dimension and a large torque transmission capacity. In the design process, a Bingham viscoplastic model is used to predict the transmitted torque. Electromagnetic finite element analysis (FEA) is performed to assist the magnetic circuit design and structural parameters' optimization. The novel brake design is prototyped and studied. Experimental results show that a compact MR fluid brake with high transmitted torque is successfully achieved.

We extend the work of A. Ciaffaglione and P. di Gianantonio on the mechanical verification of algorithms for exact computation on real numbers, using infinite streams of digits implemented as a co-inductive type. Four aspects are studied. The first concerns the proof that digit streams correspond to axiomatised real numbers when they are already present in the proof system. The second re-visits the definition of an addition function, looking at techniques to let the proof search engine perform the effective construction of an algorithm that is correct by construction. The third concerns the definition of a function to compute affine formulas with positive rational coefficients. This is an example where we need to combine co-recursion and recursion. Finally, the fourth aspect concerns the definition of a function to compute series, with an application on the series that is used to compute Euler's number e. All these experiments should be reproducible in any proof system that supports co-inductive types, co-recursion and general forms of terminating recursion; we used the COQ system (Dowek et al. 1993; Bertot and Castéran 2004; Giménez 1994).

Large scale real number computation is an essential ingredient in several modern mathematical proofs. Because such lengthy computations cannot be verified by hand, some mathematicians want to use software proof assistants to verify the correctness of these proofs. This paper develops a new implementation of the constructive real numbers and elementary functions for such proofs by using the monad properties of the completion operation on metric spaces. Bishop and Bridges's notion (Bishop and Bridges 1985) of regular sequences is generalised to what I call regular functions, which form the completion of any metric space. Using the monad operations, continuous functions on length spaces (which are a common subclass of metric spaces) are created by lifting continuous functions on the original space. A prototype Haskell implementation has been created. I believe that this approach yields a real number library that is reasonably efficient for computation, and still simple enough to verify its correctness easily.

The Coq system is a Curry–Howard based proof assistant. Therefore, it contains a full functional, strongly typed programming language, which can be used to enhance the system with powerful automation tools through the implementation of reflexive tactics. We present the implementation of a cylindrical algebraic decomposition algorithm within the Coq system, whose certification leads to a proof producing decision procedure for the first-order theory of real numbers.

The title Constructive analysis, types and exact real numbers covers the wide field of research dealing with ‘precise’ computationson continuous structures. The adjective ‘precise’ is used here in an informal way, referring to computations where the rounding off of the output and the approximative nature of the input are explicitly taken nto account in some way.