This paper proposed a novel three degree of freedom (DOF) parallel manipulator—two translations and one rotation. The mobility study and inverse kinematic analysis are conducted, and a CAD model is presented showing the design features. The optimization techniques based on artificial intelligence approaches are investigated to improve the system stiffness of the proposed 3-DOF parallel manipulator. Genetic algorithms and artificial neural networks are implemented as the intelligent optimization methods for the stiffness synthesis. The mean value and the standard deviation of the global stiffness distribution are proposed as the design indices. Both the single objective and multi-objective optimization issues are addressed. The effectiveness of this methodology is validated with Matlab.

Many object surfaces involve a number of pieces, expressed by different equations. Previous methods of optimal grasp planning can hardly cope with such cases. Ding et al. solve this problem by characterizing the object surface with convex facets and discrete points, then selecting the eligible ones for force-closure, and finally seeking the optimal contact positions on the selected elements. So far, however, no point contact with friction (PCwF) but only frictionless point contacts (FPC) can be used on the facets, while soft finger contacts (SFC) are excluded at all. In this paper, to the above two surface elements we add line segments. Moreover, the limitations on the contact types are completely removed. A general condition and a quantitative criterion of eligibility are presented, followed by a heuristic algorithm and an iterative algorithm for finding the better eligible elements. Three common examples show: the new advances make the formerly tough problems smoothly solvable.

This article sets out to identify key competencies which language tutors need to develop in order to manage synchronous online teaching. In order to aptly monitor interactions with distant learners, it is proposed that three types of regulation pertaining to socio-affective, pedagogical and multimedia aspects are required. On the one hand, this research aims at specifying these competencies and, on the other hand, it seeks to identify the relevance of reflective analysis for professional development.

The context of this study is a teacher training programme for Masters Degree students in teaching French as a foreign language that provides trainees with the opportunity of teaching online to intermediate-level students of French from a North American university via a desktop videoconferencing platform. This programme first endeavours to put trainees in a professional situation by getting them to prepare and administer sessions in order to confront them with the specific challenges of synchronous online tutoring. Second, it seeks to help them to gain insight into their own activity by developing critical thinking towards their own practice.

The data elicited for this research derive from the tutor trainees’ interpretations of their own practice when confronted with the film of their own situated activity. The episodes chosen by the trainees to feed the self-confrontation process constitute significant units because by being told and commented upon, they elucidate how and to what extent competencies are built. Three discursive strategies have been identified and used to organise the content analysis of the data: description; expression of a difficulty; reflective review of the activity. The strategies used by trainees to verbalise their own activity can inform teacher educators about the constraints of the work situation and about the resources trainees need to deploy to face up to this unknown professional situation.

Results indicate that trainees concentrate particularly on pedagogical aspects that distance and faulty technology have rendered complex. The encountered difficulties are equally distributed between a repertoire of competencies pertaining to language teaching and competencies more directly linked with online teaching. Finally, this study has enabled us to assess the potential of self-confrontation for teacher practice and leads us to propose directions for improving this training device.

Traditional algorithms for description logic (DL) instance retrieval are inefficient for large amounts of underlying data. As DL is becoming more and more popular in areas such as the Semantic Web and information integration, it is very important to have systems which can reason efficiently over large data sets. In this paper we present an approach to transform DL axioms, formalised in the DL language, into a Prolog program under the unique name assumption. This transformation is performed with no knowledge about particular individuals: they are accessed dynamically during the normal Prolog execution of the generated program. This technique, together with the top-down Prolog execution, implies that only those pieces of data are accessed that are indeed important for answering the query. This makes it possible to store the individuals in a database instead of memory, which results in better scalability and helps in using DL ontologies directly on top of existing information sources. The transformation process consists of two steps: (1) the DL axioms are converted to first-order clauses of a restricted form, and (2) a Prolog program is generated from these clauses. Step (2), which is the focus of the present paper, actually works on more general clauses than those obtainable by applying step (1) to a knowledge base. We first present a base transformation, the output of which can be either executed using a simple interpreter or further extended to executable Prolog code. We then discuss several optimisation techniques, applicable to the output of the base transformation. Some of these techniques are specific to our approach, while others are general enough to be interesting for DL reasoner implementors not using Prolog. We give an overview of DLog, a DL reasoner in Prolog, which is an implementation of the techniques outlined above. We evaluate the performance of DLog and compare it to some widely used DL reasoners, such as RacerPro, Pellet and KAON2.

This paper presents a quadratic programming (QP) form algorithm to realize on-line planning of mobile manipulators with consideration for improving the stability level. With Lie group and screw tools, the general tree topology structure mobile robot dynamics and dynamic stability attributes were analysed. The stable support condition for a mobile robot is constructed not only in a polygonal support region, but also in a polyhedral support region. For a planar supporting region, the tip-over avoiding requirement is formulated as the tip-over prevent constraints with the reciprocal products of the resultant support wrench and the imaginary tip-over twists, which are constructed with the boundaries of the convex support polygon. At velocity level, the optimized resolution algorithm with standard QP form is designed to resolve the inverse redundant kinematics of the Omni-directional Mobile ManipulatorS (OMMS) with stability considerations. Numerical simulation results show that the presented methods successfully improve the stability level of the robot within an on-line planning process.

This paper deals with the computation of the orientation error and the kinematic model of a 3-DOF translational parallel manipulator called the RAF robot. We derived a simple analytical model allowing the computation of the orientation, generated by the deformation of the PKLs, when an external load is applied to the platform. These models allowed us to map the orientation error on the workspace of the robot. We showed in particular that the minimum orientation error can be obtained when the platform is in a certain region of its workspace. Due to its analytical nature, the developed model can also be used for a sensitivity analysis in order to maximize the manipulator precision.

As Japanese uses three writing systems (hiragana, katakana, and the ideograms known as kanji), and as materials in the target language include all three, it is a major challenge to learn to read and write quickly. This paper focuses on interactive multi-media methods of teaching Japanese reading which foster learner autonomy.

As little has been published on interactive multi-media methods of teaching Japanese reading, it seems likely that traditional resources are generally used for this activity. The courseware includes sound files showing the pronunciation of each kana as well as simultaneous animation showing how to write each character. This paper investigates whether interactive courseware, used independently of classroom interaction, results in measurably greater recognition of the hiragana syllabary than more traditional methods. After briefly situating the study in the context of research on the teaching of Japanese reading and learner autonomy, the paper will present the courseware as well as an empirical study comparing the results of the use of the courseware by learners at beginners’ level: one group using the courseware, and the other using paper-based materials. This is followed by an account of learner diaries written by zero-beginner level learners of Japanese using the courseware.

The study indicates that acquisition of a recognition-level knowledge of hiragana is approximately twice as fast using the courseware as using paper-based materials. Learners also learned to write the hiragana without explicit instruction.

A path planning algorithm for a spherical mobile robot rolling on a plane is presented in this paper. The robot is actuated by two internal rotors that are fixed to the shafts of two motors. These are in turn mounted on the spherical shell in mutually orthogonal directions. The system is nonholonomic due to the nonintegrable nature of the rolling constraints. Further, the system cannot be converted into a chained form, and neither is it nilpotent nor differentially flat. So existing techniques of nonholonomic path planning cannot be applied directly to the system. The approach presented here uses simple geometrical notions and provides numerically efficient and intuitive solutions. We also present the dynamic model and derive motor torques for execution of the algorithm. Along the proposed paths, we achieve dynamic decoupling of the variables making the algorithm more suitable for practical applications.

The following paper presents two stages of an action research project involving two oral proficiency courses held in the virtual world Second Life. Course 1 was conducted during the Autumn of 2007. Based on the experiences of this course, we redesigned many aspects of it in order to improve student activity in terms of oral participation and gave the course again in Spring 2008. By analysing the recordings of four 90-minute sessions, two from each course, we were able to measure student participation based on floor space, turn lengths and turn-taking patterns, and in the study we discuss how different changes in design may have contributed to more favourable outcomes. Results seem to indicate that meaning focussed task design, which involves authenticity and collaborative elements, has a direct impact on learner participation and engagement. Furthermore, our results seem to suggest that technical and social initiations into a complex environment such as SL are important factors that have to be worked into the course design.

The present paper proposes a successful application of differential evolution (DE) optimized fuzzy logic supervisors (FLS) to improve the quality of solutions that extended Kalman filters (EKFs) can offer to solve simultaneous localization and mapping (SLAM) problems for mobile robots and autonomous vehicles. The utility of the proposed system can be readily appreciated in those situations where an incorrect knowledge of Q and R matrices of EKF can significantly degrade the SLAM performance. A fuzzy supervisor has been implemented to adapt the R matrix of the EKF online, in order to improve its performance. The free parameters of the fuzzy supervisor are suitably optimized by employing the DE algorithm, a comparatively recent method, popularly employed now-a-days for high-dimensional parallel direct search problems. The utility of the proposed system is aptly demonstrated by solving the SLAM problem for a mobile robot with several landmarks and with wrong knowledge of sensor statistics. The system could successfully demonstrate enhanced performance in comparison with usual EKF-based solutions for identical environment situations.

In our previous work, a novel force control actuator, called series damper actuator (SDA), has been proposed. This paper proposes a general design procedure for the SDA system. From design requirements, several key parameters of the SDA plant can be determined. Based on these parameters, the selection or design of the series damper and the motor can be carried out. A case study is included to illustrate the effectiveness of the procedure. As there could be more than one feasible solutions from the procedure, the mechatronic design quotient (MDQ) method can be adopted to select the best solution from a feasible solution space.

The paper introduces fuzzy linguistic logic programming, which is a combination of fuzzy logic programming, introduced by P. Vojtáš, and hedge algebras in order to facilitate the representation and reasoning on human knowledge expressed in natural languages. In fuzzy linguistic logic programming, truth values are linguistic ones, e.g., VeryTrue, VeryProbablyTrue and LittleFalse, taken from a hedge algebra of a linguistic truth variable, and linguistic hedges (modifiers) can be used as unary connectives in formulae. This is motivated by the fact that humans reason mostly in terms of linguistic terms rather than in terms of numbers, and linguistic hedges are often used in natural languages to express different levels of emphasis. The paper presents: (a) the language of fuzzy linguistic logic programming; (b) a declarative semantics in terms of Herbrand interpretations and models; (c) a procedural semantics which directly manipulates linguistic terms to compute a lower bound to the truth value of a query, and proves its soundness; (d) a fixpoint semantics of logic programs, and based on it, proves the completeness of the procedural semantics; (e) several applications of fuzzy linguistic logic programming; and (f) an idea of implementing a system to execute fuzzy linguistic logic programs.

This paper presents a snapshot of what has been investigated in terms of the relationship between machine translation (MT) and foreign language (FL) teaching and learning. For this purpose four different roles of MT in the language class have been identified: MT as a bad model, MT as a good model, MT as a vocational training tool (especially in the form of translation memories, pre-editing and post-editing), and MT as a “CALL tool”. Subsequently, some of the implications of the use of MT and of free online MT for FL learning are outlined and discussed along with practical examples for language teaching purposes. Finally, qualitative data, drawn from our empirical investigation are presented as synthesized findings pertaining to the perceptions of language learners and tutors in relation to the use of MT and, in particular, free online MT as a language tool.

This paper presents a polar-space kinematics control method to achieve simultaneous tracking and stabilization for an omnidirectional wheeled mobile robot with three independent driving omnidirectional wheels equally spaced at 120° from one another. The kinematic model of the robot in polar coordinates is presented. With the kinematic model, a kinematic control method based on feedback linearization is proposed in order to achieve simultaneous tracking and stabilization. The proposed method is easily extended to address the path following problem. Computer simulations and experimental results are presented to show the effectiveness and usefulness of the proposed control method at slow speeds.

In order to make optimal educational use of social spaces offered by thousands of international communities in the second generation web applications termed Web 2 or Social Web, ICT competences as well as social skills are needed for both teachers and learners. The paper outlines differences in competence structures of Net Natives (who came of age in the 21st century) and the Net Generation of the 1980s and 1990s who evolve in response to changes between Web 1 and Web 2 technologies.

Virtual educational environments in the age of the Social Web represent a perfect embodiment of the Constructionist paradigm: they offer shared discussion and work spaces instead of presentation tools, coaching utilities instead of help desks, and digital learning resource repositories instead of ready-made learning materials. LRE, the European Learning Resource Exchange, and several collaborative web based services and applications will be presented, to illustrate the interrelated change in educational software design and use.

New teaching and learning aids require and at the same time inspire new educational theories. The trialogical learning paradigm that invites all educational stakeholders to work on shared objects of inquiry and development and thus develop epistemic agency will be offered as a foundation for a ‘social CALL’.

An exact formula for the expected length of the minimum spanning tree of a connected graph, with independent and identical edge distribution, is given, which generalizes Steele's formula in the uniform case. For a complete graph, the difference of expected lengths between exponential distribution, with rate one, and uniform distribution on the interval (0, 1) is shown to be positive and of rate ζ(3)/n. For wheel graphs, precise values of expected lengths are given via calculations of the associated Tutte polynomials.