Collaborative recommendation of e‐learning resources: an experimental investigation

Repositories with educational resources can support the formation of online learning communities by providing a platform for collaboration. Users (e.g. teachers, tutors and learners) access repositories, search for interesting resources to access and use, and in many cases, also exchange experiences and opinions. A particular class of online services that take advantage of the collected knowledge and experience of users are collaborative filtering ones. The successful operation of such services in the context of real‐life applications requires careful testing and parameterization before their actual deployment. In this paper, the case of developing a learning resources' collaborative filtering service for an online community of teachers in Europe was examined. More specifically, a data set of evaluations of learning resources was collected from the teachers that use the European Schoolnet's learning resource portal. These evaluations were then used to support the experimental investigation of design choices for an online collaborative filtering service for the portal's learning resources. A candidate multi‐attribute utility collaborative filtering algorithm was appropriately parameterized and tested for this purpose. Results indicated that the development of such systems should be taking place considering the particularities of the actual communities that are to be served.     

Towards consistent modes of e‐health implementation: structurational analysis of a telecare programme's limited success

Telecare is the use of information and communication systems to facilitate care delivery to individuals in their homes. Although the expectations of telecare are high, its implementation has proved complex. This case study demonstrates this complexity through a structurational analysis of a telecare implementation process. The paper shows how structuration concepts enable a combined analysis of actors' interactions with a technology and of the interaction among these actors from different institutional contexts. In this example, fragmented multi‐actor agency induced an inconsistent implementation mode, leading to unsuccessful telecare appropriation. This paper concludes with a preliminary proposal for more consistent telecare implementation modes. These modes may better support the actors' reflexive monitoring and dialogue and inform further research.     

Towards a re-programmable DNA computer

Microreactors lend themselves to a relatively simple implementation of DNA computing. Not only is the design of the DNA library critical for the success of the system but also the architecture of the microfluidic structure. Microreactors can be configured as Boolean operators. This paper will show that biomolecular computing can be performed with elementary building blocks, analogous to electronic logic gates. These logical operations will be performed using negative selection. Furthermore, an alternative bead barrier is introduced which can render the computer re-programmable and shows an principle architecture for selection and analysis.     

The Pneumatic Biped “Lucy” Actuated with Pleated Pneumatic Artificial Muscles

This paper reports on the bipedal robot Lucy which is actuated by pleated pneumatic artificial muscles. This novel actuator is very suitable to be used in machines which move by means of legs. Besides its high power to weight ratio the actuator has an adaptable passive behavior, meaning the stiffness of the actuator can be changed on-line. This allows to change the natural frequency of the system while controlling angular joint positions. The main control concept intended for Lucy is joint trajectory control while selecting appropriate actuator compliance characteristics in order to reduce control efforts and energy consumption which is of great importance towards the autonomy of legged robots. Presently Lucy has made her first steps with the implementation of basic control strategies.The pleated pneumatic artificial muscle and its characteristics will be discussed briefly and the design of Lucy which is made modular on mechanical as well as electronic hardware level will be described in detail. To pressurize the muscles, a lightweight valve system has been developed which will be presented together with the fundamental control aspects of a joint actuated with two antagonistically setup artificial muscles. Additionally the first experimental results will be shown and briefly discussed.Björn Verrelst (1972) Study of Mechanical Engineering at the Vrije Universiteit Brussel, graduated in 1996. Since 1998 researcher and teaching assistant at the Vrije Universiteit Brussel. The focus of his research is the use of pneumatic artificial muscles in the walking biped Lucy for dynamically balanced walking.Ronald Van Ham (1976) Study of Electro-Mechanical Engineering at the Vrije Universiteit Brussel, graduated in 1999. Since 1999 researcher and teaching assistant at the Vrije Universiteit Brussel. The focus of his research is the use of adaptable compliance of pneumatic artificial muscles in the walking biped Lucy.Bram Vanderborght (1980) Study of Mechanical Engineeringat the Vrije Universiteit Brussel, graduated in 2003. Since 2003 researcher at the Vrije Universiteit Brussel, supported by the Fund for Scientific Research Flanders (Belgium). The focus of his research is the use of adaptable compliance of pneumatic artificial muscles in the dynamically balanced biped Lucy.Frank Daerden (1966) Study of Mechanical Engineering at the Vrije Universiteit Brussel. Ph.D. in Applied Sciences, Vrije Universiteit Brussel, 1999. Research and teaching assistant at the Vrije Universiteit Brussel, 1991–1999. Doctor-Assistant at the dept. of Mechanical Engineering, Vrije Universiteit Brussel since 1999, visiting Professor since 2003.Dirk Lefeber (1956) Study of Civil Engineering at the Vrije Universiteit Brussel. Ph.D. in Applied Sciences, Vrije Universiteit Brussel, 1986. Professor at the dept. of Mechanical Engineering, head of the Multibody Mechanics Research Group, Vrije Universiteit Brussel.Jimmy Vermeulen (1973) Study of Mechanical Engineering at the Vrije Universiteit Brussel. Ph.D. in Applied Sciences, Vrije Universiteit Brussel, 2004. Research and teaching assistant at the Vrije Universiteit Brussel, 1996–2004. Post-Doctoral researcher at the dept. of Mechanical Engineering, Vrije Universiteit Brussel since 2004. The focus of his research is trajectory generation and control of dynamically balanced legged robots.     

Enhancing the impact of ergonomics interventions

The aim of this paper was to provide recommendations for ergonomists involved in project design and evaluation. Twelve research and consultancy projects involving ergonomics interventions in a variety of settings in The Netherlands were analysed to identify factors important to success. Projects included participatory and non-participatory cases. Eight factors were identified for successful project design and for demonstrating project effectiveness.     

Analyzing existing customers’ websites to improve the customer acquisition process as well as the profitability prediction in B-to-B marketing

We investigate the issue of predicting new customers as profitable based on information about existing customers in a business-to-business environment. In particular, we show how latent semantic concepts from textual information of existing customers’ websites can be used to uncover characteristics of websites of companies that will turn into profitable customers. Hence, the use of predictive analytics will help to identify new potential acquisition targets. Additionally, we show that a regression model based on these concepts is successful in the profitability prediction of new customers. In a case study, the acquisition process of a mail-order company is supported by creating a prioritized list of new customers generated by this approach. It is shown that the density of profitable customers in this list outperforms the density of profitable customers in traditional generated address lists (e.g. from list brokers). From a managerial point of view, this approach supports the identification of new business customers and helps to estimate the future profitability of these customers in a company. Consequently, the customer acquisition process can be targeted more effectively and efficiently. This leads to a competitive advantage for B2B companies and improves the acquisition process that is time- and cost-consuming with traditionally low conversion rates.     

Development of constrained control allocation for ship berthing by using autonomous tugboats

International Journal of Control, Automation and Systems - In this paper, we propose a new approach to ship berthing by using autonomous tugboats. This approach overcomes the nominal effectiveness...     

Splines from a Bayesian point of view

Summary Procedures using splines for estimating values of linear functionals of an unknown function based on finitely many possibly noisy observations of function values are reviewed taking a Bayesian point of view. Interpolation with splines is emphasized as an example of Bayesian numerical analysis, smoothing with splines is presented as interpolation in estimated function values. Extensions of the approach to estimating values of non-linear functionals applied to the unknown function and to estimation subject to linear constaints on the unknown function are discussed. Furthermore, invariance of Bayesian inference to modifications of the prior distribution, resulting from alternative choices of an appropriate function space for estimation, is addressed, too.     

Comparative study of the surface oxidation behaviour of amorphous and crystallized Fe67Co18B14Si1 metallic glass

The oxidation of amorphous and crystallized specimens of the metallic glass Fe₆₇Co₁₈B₁₄Si₁ were studied under controlled conditions using Auger electron spectroscopy and X-ray photo-electron spectroscopy. The different oxides were characterized as boron and iron oxide forming in that sequence for both the amorphous and crystalline specimens. No cobalt oxide was detected. A higher oxygen uptake was measured for the amorphous than for the crystalline specimens. Comparison with the literature shows that the difference in oxygen uptake is heavily composition dependent. The oxidation of the amorphous specimens constitutes a driving force for boron to segregate to the surface and causes a boron enriched layer. Segregation of boron and cobalt occurs during annealing and the sequence of the enriched layers is influenced by environmental conditions.     

A variational approach to magnetoelastic buckling problems for systems of superconducting tori

A variational principle for the magnetoelastic stability problem of superconductors is constructed. Independently, a pair of integral equations is derived, from which the initial and the perturbed field can be computed. The integral equations are solved for in-plane buckling of a slender pair of concentric tori, and out-of-plane buckling of a slender pair of equal coaxial tori. By using the variational principle, it is shown that both cases can become unstable when the currents on the two tori are equally directed, and the pertinent buckling values are calculated. The thus obtained buckling values are compared with the results of an alternative, mathematically less rigorous, method. A good correspondence between the two methods is found (at least as long as the two tori are not too near).