Using Landsat 7 ETM+ imagery and Digital Terrain Models for mapping glacial lineaments on former ice sheet beds

In this paper, we consider the application of Landsat 7 ETM+ imagery and Digital Terrain Models (DTM) for mapping glacial lineaments in a formerly glaciated area of Wales. A series of landform interpretation experiments were conducted using different false colour composites (FCC) and a DTM, both individually and in combination. The experiments indicate that the optimal FCC for detection of glacial lineaments at this scale includes the thermal‐infrared (TIR) band. However, by performing the interpretation both in the TIR composite and in a visible and near‐infrared (VNIR, bands 4, 3, and 2) draped over the DTM, we were able to substantially increase the number of lineaments identified. The glacial lineaments consist of fractured bedrock and are defined as rock drumlins. The landform system formed by these rock drumlins is characterized by convergent flow patterns at its head, attenuated lineaments, and abrupt lateral margins, which may indicate formation by fast‐flowing ice.     

Handwritten Chinese character recognition using fuzzy image alignment

The task of handwritten Chinese character recognition is one of the most challenging areas of human handwriting classification. The main reason for this is related to the writing system itself which encompasses thousands of characters, coupled with high levels of diversity in personal writing styles and attributes. Much of the existing work for both online and off-line handwritten Chinese character recognition has focused on methods which employ feature extraction and segmentation steps. The preprocessed data from these steps form the basis for the subsequent classification and recognition phases. This paper proposes an approach for handwritten Chinese character recognition and classification using only an image alignment technique and does not require the aforementioned steps. Rather than extracting features from the image, which often means building models from very large training data, the proposed method instead uses the mean image transformations as a basis for model building. The use of an image-only model means that no subjective tuning of the feature extraction is required. In addition by employing a fuzzy-entropy-based metric, the work also entails improved ability to model different types of uncertainty. The classifier is a simple distance-based nearest neighbour classification system based on template matching. The approach is applied to a publicly available real-world database of handwritten Chinese characters and demonstrates that it can achieve high classification accuracy and is robust in the presence of noise.     

Can the interactive whiteboard support young children’s collaborative communication and thinking in classroom science activities?

Interactive whiteboards (IWBs) have been widely introduced to English primary schools (5–11 years) in the last decade and this has generated much research interest. In the past, research has focused on IWB-use in teacher-led sessions, attending particularly to the nature of teacher-pupil interaction at the IWB and the apparent motivational advantages for children. In contrast, this study focuses on children’s communication and thinking during their semi-autonomous use of the IWB during collaborative groupwork in primary school science lessons, aiming in part to see if the IWB is suited to this type of use. Over the course of one school year, twelve primary teachers of Years 4 and 5 (8–10 years) took part in a professional development and research programme which involved them in devising a sequence of three science lessons incorporating small-group activity at the IWB. The functionality of the IWB is analysed here as means for supporting the children’s joint communication and thinking, using embedded cues and the availability of certain features in the IWB technology. Our observational analysis of two examples of children’s collaborative activity in different classrooms, together with subsequent group interviews, suggests that the IWB can make some identifiable contributions to children’s productive communication and thinking. However the IWB is not seen to be an entirely distinctive or pedagogically transformative learning resource in the primary classroom. In our developing conceptual framework, the children’s knowledge building is closely related to their active engagement in using IWB affordances and their productive dialogue, essentially supported by the teacher’s scaffolding strategies, the establishment and use of “talk rules” in conversation, and the opportunities and constraints applying in classroom participation structures. These conditions help the children to deal with interconnected social, cognitive, and technical problems arising over time. Certain aspects of this form of computer-supported collaborative learning (CSCL) are discussed. These relate to the integration of the IWB with other classroom learning systems and resources, and to the nature of progression in children’s activity and learning with this new type of highly integrated system of CSCL.     

Under the weather: an evaluation of different modes of presenting meteorological information for pilots

Understanding current and forecast weather conditions for a planned route of flight is vital for general aviation (GA) pilots. Weather information can be obtained from multiple sources and in multiple formats, ranging from abbreviated code provided by aviation weather forecasters to animated graphical displays available on TV and the Internet. The present study investigated the effectiveness of graphical displays of meteorological information. A commercially available graphical display was ergonomically redesigned and the original and redesigned displays were compared with an ordinary text statement. Recall of information was significantly affected by display type. Comparisons showed the ergonomically redesigned display to be superior to the ordinary text statement. Performance was affected by participants’ general level of familiarity with evaluating data displays as measured by their area of study (sciences or humanities). The generalizability of the results to the pilot population is discussed.     

Structural identifiability analysis via symmetries of differential equations

Results and derivations are presented for the generation of a local Lie algebra that represents the ‘symmetries’ of a set of coupled differential equations. The subalgebra preserving the observation defined on the model structure is found, thus giving all transformations of the system that preserve its structure. It is shown that this is equivalent to the similarity transformation approach (Evans, Chapman, Chappell, & Godfrey, 2002) for structural identifiability analysis and as such is a method of generating such transformations for this approach. This provides another method for performing structural identifiability analysis on nonlinear state-space models that has the possibility of extension to PDE type models. The analysis is easily automated and performed in Mathematica, and this is demonstrated by application of the technique to a number of practical examples from the literature.     

Corrosion fatigue testing: the combined effect of stress and high temperature corrosion

Abstract

A corrosive environment can have a detrimental effect on the fatigue life of a material due to a change in failure mechanism. Attempts have been made to replicate this change on nickel-base superalloy CMSX-4 cast in the <001> orientation. Fatigue testing in air, of this material typically produces a fracture on an angle of approximately 55° which is consistent with the fracture having propagated on a {111} slip plane. The aim of the research was to fatigue test in a corrosive environment with the purpose of producing a crack/fracture which deviated from the typical angle and thus confirm that the corrosive environment had affected the fatigue mechanism. It was concluded that the change in mechanism to high temperature corrosion fatigue was associated with a reduced load application rate together with precorroding the test specimens to trigger the initiation of the corrosion fatigue mechanism.     

Performance characterization in computer vision: A guide to best practices

It is frequently remarked that designers of computer vision algorithms and systems cannot reliably predict how algorithms will respond to new problems. A variety of reasons have been given for this situation and a variety of remedies prescribed in literature. Most of these involve, in some way, paying greater attention to the domain of the problem and to performing detailed empirical analysis. The goal of this paper is to review what we see as current best practices in these areas and also suggest refinements that may benefit the field of computer vision. A distinction is made between the historical emphasis on algorithmic novelty and the increasing importance of validation on particular data sets and problems.     

Computational complexity via programming languages: constant factors do matter

The purpose of this work is to promote a programming-language approach to studying computability and complexity, with an emphasis on time complexity. The essence of the approach is: a programming language, with semantics and complexity measure, can serve as a computational model that has several advantages over the currently popular models and in particular the Turing machine. An obvious advantage is a stronger relevance to the practice of programming. In this paper we demonstrate other advantages: certain proofs and constructions that are hard to do precisely and clearly with Turing machines become clearer and easier in our approach, and sometimes lead to finer results. In particular, we prove several time hierarchy theorems, for deterministic and non-deterministic time complexity which show that, in contrast with Turing machines, constant factors do matter in this framework. This feature, too, brings the theory closer to practical considerations. The above result suggests that this framework may be appropriate for studying low complexity classes, such as linear time. As an example we give a problem complete for non-deterministic\/ linear time under deterministic linear-time reductions. Finally, we consider some extensions and modifications of our programming language and their effect on time complexity results. Received: 26 October 1998 / 9 June 2000     

Benzophenone reduction using sulphur-based additives

Pyrite and γ-Fe₂S₃ are the best of the mineral promotors tried for the CO—H₂O reduction of benzophenone to diphenylmethane. A mixture of ferrous sulphide and sulphur matches the promotional effect of iron pyrite, which implies that sulphur plays a role in the reaction. Both elemental sulphur and hydrogen sulphide are shown to promote CO—H₂O-induced reductions.