Discovering stages in web navigation for problem-oriented navigation support

Users of web sites often do not know exactly which information they are looking for nor what the site has to offer. The purpose of their interaction is not only to fulfill but also to articulate their information needs. In these cases users need to pass through a series of pages before they can use the information that will eventually answer their questions. Current systems that support navigation predict which pages are interesting for the users on the basis of commonalities in the contents or the usage of the pages. They do not take into account the order in which the pages must be visited. In this paper we propose a method to automatically divide the pages of a web site on the basis of user logs into sets of pages that correspond to navigation stages. The method searches for an optimal number of stages and assigns each page to a stage. The stages can be used in combination with the pages’ topics to give better recommendations or to structure or adapt the site. The resulting navigation structures guide the users step by step through the site providing pages that do not only match the topic of the user’s search, but also the current stage of the navigation process.     

Classification accuracy is not enough

We argue that an evaluation of system behavior at the level of the music is required to usefully address the fundamental problems of music genre recognition (MGR), and indeed other tasks of music information retrieval, such as autotagging. A recent review of works in MGR since 1995 shows that most (82 %) measure the capacity of a system to recognize genre by its classification accuracy. After reviewing evaluation in MGR, we show that neither classification accuracy, nor recall and precision, nor confusion tables, necessarily reflect the capacity of a system to recognize genre in musical signals. Hence, such figures of merit cannot be used to reliably rank, promote or discount the genre recognition performance of MGR systems if genre recognition (rather than identification by irrelevant confounding factors) is the objective. This motivates the development of a richer experimental toolbox for evaluating any system designed to intelligently extract information from music signals.     

SMALL-SCALE RECOVERY AND SEPARATION OF ACTINIDES USING TRI-n-BUTYL PHOSPHATE EXTRACTION CHROMATOGRAPHY

The small-scale recovery and separation of the actinides U, Np, Pu and Am using the commercial product, Lewatit OC 1023. has been studied. Conditions under which these actinides may be extracted or eluted and methods for separation of any combination of these elements are presented. A separation scheme for all four actinides achieved complete separation of Np from U and Am from Pu and U. Good separation of U, Np and Pu was achieved. Quantitative separation is possible by repeating the procedure.

Since Np and Am follow one another in the above scheme, a further procedure for their quantitative separation is presented.

Reductants investigated for separation of Pu from U were ferrous sulfamate and hydroxylamraonium nitrate. The latter is only effective if small amounts of U are present.

The behaviour of Ru and Zr under the conditions for the separation of U, Np, Pu and Am was also investigated The behaviour of these two troublesome elements was shown to be similar to that in the purex process.     

The impact of barley straw conditioning on the inhibition of Scenedesmus using chemostats

The current paper investigates the role of barley straw conditioning on inhibiting the alga Scenedesmus. Fresh, pre-rotted and white rot fungi (WRF) augmented straw was tested in a series of chemostat experiments over 15 weeks. All three systems were effective at inhibiting the alga with differences observed in the lag time before inhibition occurred and the rate of alga decline. Lag times of 8, 4 and 1 week(s) were recorded for the fresh, rotted and fungi-treated straws, respectively, with a maximum inhibition rate of >7 × 10⁴ cells week⁻¹ observed for the fungi pre-treated system. Overall, the results indicate that pre-treatment is a viable method to enable barley straw to be used in a more reactive manner. Explanation is postulated that during pre-treatment no alternative sources of nitrogen are available, thereby leading to greater bacterial decomposition of straw lignin to release inhibitory substances. The principle of utilising an engineered pre-treatment by inoculating barley straw with WRF to enhance the impact of the straw on algal inhibition has been clearly demonstrated. Further work is required to understand how the straw pre-treatment stage can be reduced to minimise its duration while maximising the inhibitory effect of adding barley straw.     

Ubiquitous Computing in the Biology Laboratory

Our objective is to eliminate the digital divide that persists between the physical and information spaces of wet-lab based enterprises by embedding computational resources into the shared laboratory environment. Our first challenge is to enable individual lab workers to contribute to a fine-grained formal representation of ongoing lab activities - to build the database by doing the work, without having to stop and write things down in a notebook or to enter information into a computer. By eliminating the redundancy of doing the work and then recording it, accuracy and completeness will be improved. And, by capturing information at a finer detail than is practical for manual entry systems, unanticipated applications can be supported.