7659346
Skill Acquisition and the LISP Tutor
An analysis of student learning with the LISP tutor indicates that while LISP is complex, learning it is simple. The key to factoring out the complexity of LISP is to monitor the learning of the 500 productions in the LISP tutor which describe the programming skill. The learning of these productions follows the power-law learning curve typical of skill acquisition. There is transfer from other programming experience to the extent that this programming experience involves the same productions. Subjects appear to differ only on the general dimensions of how well they acquire the productions and how well they retain the productions. Instructional manipulations such as remediation, content of feedback, and timing of feedback are effective to the extent they give students more practice programming, and explain to students why correct solutions work.
22373766
Explorations of an incremental, Bayesian algorithm for categorization
An incremental categorization algorithm is described which, at each step, assigns the next instance to the most probable category. Probabilities are estimated by a Bayesian inference scheme which assumes that instances are partitioned into categories and that within categories features are displayed independently and probabilistically. This algorithm can be shown to be an optimization of an ideal Bayesian algorithm in which predictive accuracy is traded for computational efficiency. The algorithm can deliver predictions about any dimension of a category and does not treat specially the prediction of category labels. The algorithm has successfully modeled much of the empirical literature on human categorization. This paper describes its application to a number of data sets from the machine learning literature. The algorithm performs reasonably well, having its only serious difficulty because the assumption of independent features is not always satisfied. Bayesian extensions to deal with nonindependent features are described and evaluated.
17702751
The Geometry Tutor
The tutor for doing proofs in high school geometry consists of a cot of ideal and buggy rules (IRR), a tutor, and an interface. The IBR is responsible for ehiuertly computing matcher, to all the correct and incorrect rules The interface is responsible for interacting with the student and graphically representing the proof. The tutor is responsible for directing the IBR and interface to achieve a current tutorial strategy. The strategy wo employ involves tracing the student's behavior in terms of what rules in the IBR it instantiates, correcting the student when behavior deviates below a minimum threshold, and helping the student over hurdles. While incomplete, current evidence indicates the geometry tutor is guite effective. 
 
The Advanced Computer Tutoring Project has been working on the development of intelligent computerhased tutors for mathematics and science subjects in the range of senior high-school to junior college. This paper describes the general framework that we have developed and its instantiation in the case of a tutor tor generating proofs in geometry. First, we will describe the general philosophy of out tutoring efforts. Second, we will describe the basic structure of the geometry tutor that we have built. Third, we will describe the ongoing efforts to evaluate the tutor.
1998598
Dynamic Student Modelling in an Intelligent Tutor for LISP Programming
We describe an intelligent tutor for LISP programming. This tutor achieves a set of pedagogical objectives derived from Anderson's (1983) learning theory provide instruction in the context of problem-solving, have the student generate as much of each solution as possible, provide immediate feedback on errors, and represent the goal structure of the problem-solving. The tutorial interface facilitates communication and prevents distracting low-level errors Field tests of the tutor in college classes demonstrate that it is more effective than conventional classroom instruction.
45489934
Usability Assessment of Collaborative Shared-Space Telepresence Shopping Services
This paper describes the methodology and procedure of usability trials undertaken as part of the ACTS Teleshoppe project; it also details and analyses the results of the trials. The aim of the trials was to assess user attitudes to a collaborative shared-space shopping service. Usability data were obtained using a series of Likert-style questionnaires and through a 'focus group' discussion performed with a representative subset of the trial participants. The paper presents this data and draws conclusions relevant to the future direction of research and implementation for such shopping services. In particular, the results of the trials indicate a generally positive attitude towards the collaborative shopping service used. Furthermore, those aspects of the service viewed negatively by the users are for the most part aspects which can be easily rectified and not due to technological limitations.
19285984
Surface Based Hypothesis Verification in Intensity Images Using Geometric and Appearance Data
In this paper we discuss current work concerning Appearance-based and CAD-based vision; two opposing vision strategies. CAD-based vision is geometry based, reliant on having complete object centred models. Appearance-based vision builds view dependent models from training images. Existing CAD-based vision systems that work with intensity images have all used one and zero dimensional features, for example lines, arcs, points and corners. We describe a system we have developed for combining these two strategies. Geometric models are extracted from a commercial CAD library of industry standard parts. Surface appearance characteristics are then learnt automatically by observing actual object instances. This information is combined with geometric information and is used in hypothesis evaluation. This augmented description improves the systems robustness to texture, specularities and other artifacts which are hard to model with geometry alone, whilst maintaining the advantages of a geometric description.
37746133
The Transfer of Text-Editing Skill
Abstract Computer-naive subjects were taught to use either one or two line editors and then a screen editor. Positive transfer was observed both between the line editors and from the line editors to the screen editor. Transfer expressed itself in terms of reductions in total time, keystrokes, residual errors, and seconds per keystroke. A simple two-component model of transfer is proposed that allows for the differential practice of general and specific components when learning a skill.