Vision-guidance of agricultural vehicles

A vision guidance system has been designed, built and commissioned which steers a tractor relative to the rows of a crop such as cotton. It was required to be insensitive to additional visual noise from weeds, while tolerating the fading out of one or more rows in a barren patch of the field. The system integrates data from several crop rows, testing for image quality. At the same time, the data processing requirements have been limited by the use of frame-sequential strategies to reduce the image space which must be processed. The design has been developed to the stage where six evaluation prototypes have been installed to test farmer-acceptance. The present prototypes employ a 486 PC motherboard embedded in a custom housing, together with a 68HC11 microcomputer to which the task of closing the steering servo loop is delegated. The system shows great promise for cost effective commercial exploitation.Experimental results are reported and further sensing systems are outlined for performing related guidance tasks when vision is inappropriate.     

Student Proof Exercises Using MathsTiles and Isabelle/HOL in an Intelligent Book

The Intelligent Book project aims to improve online education by designing materials that can model the subject matter they teach, in the manner of a reactive learning environment. In this paper, we investigate using an automated proof assistant, particularly Isabelle/HOL, as the model supporting first year undergraduate exercises in which students write proofs in number theory. Automated proof assistants are generally considered to be difficult for novices to learn. We examine whether, by providing a very specialized interface, it is possible to build something that is usable enough to be of educational value. To ensure students cannot “game the system” the exercise avoids tactic-choosing interaction styles but asks the student to write out the proof. Proofs are written using MathsTiles: composable tiles that resemble written mathematics. Unlike traditional syntax-directed editors, MathsTiles allows students to keep many answer fragments on the canvas at the same time and does not constrain the order in which an answer is written. Also, the tile syntax does not need to match the underlying Isar syntax exactly, and different tiles can be used for different questions. The exercises take place within the context of an Intelligent Book. We performed a user study and qualitative analysis of the system. Some users were able to complete proofs with much less training than is usual for the automated proof assistant itself, but there remain significant usability issues to overcome.     

Software distribution via broadcast television signals

A method is described for the transmission of software and digital data at rates of multiples of 500 baud as part of a broadcast television signal. Unlike teletext-based systems, this method enables signals to be recorded on a domestic video recorder for subsequent decoding. The receiver interface is also much simpler, consisting of low-cost, commonplace components in a configuration which can be assembled by novices.     

Reengineering the corporate culture of hospitals

As we move closer to the turn of the century, the American health care system continues to provide management experts with a wealth of case studies describing the winners and losers in today's business environment. Winners in this cost-conscious era of institutional reengineering, said Senge in his best-selling book The Fifth Discipline (1990), are those organizations that bind together around a common identity, a sense of destiny, and a shared commitment to reconciling the existing threats to their survival. Senge suggests that the organizations that are able to tap people's commitment and capacity to learn at all levels of the structure will overcome the type of maladaptation to business threats so commonly seen in corporate failures today.     

Paraprofessional skill: Maintenance of empathic sensitivity after training.

Investigated changes in empathic sensitivity in paraprofessionals as a result of training and examined the maintenance of changes 6–24 mo after training. Also explored was the relationship of verbal intelligence to changes. 47 students in an associate degree mental health/human service program participated. Each S completed a 10-wk training course in 1 of 4 groups. Each was given the Recognition Assessment—Empathy (RA—E) on completion of the course and 6–24 mo later. Ss in 2 groups were also pretested on the RA—E. Empathetic sensitivity did increase after the course, confirming previous research, and changes were not only maintained but increased over time to a level comparable with a normative group of experienced clinicians. Course drop-out and selection effects were judged to be minimal. No significant relationship emerged between verbal intelligence and empathic sensitivity either before or after training. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induced immunity against the mosquito Anopheles stephensi Liston (Diptera: Culicidae): effects on mosquito survival and fecundity

Mice were immunised three to five times with extracts of Anopheles stephensi heads, midguts, ovaries or fat bodies. At each immunisation the effects of feeding An. stephensi on the mice was determined, and changes in mosquito longevity and fecundity examined as the immune response developed. Although variability was common between control cages, significant and consistent reductions in mosquito longevity were observed when midguts were used as immunogens. Other extracts caused transient reductions in mortality. Fecundity was reduced significantly in mosquitoes fed upon mice immunised with each extract in at least one experiment. Mosquitoes fed upon fat-body-immunised mice showed delayed egg-laying as well as overall reduction in fecundity. The results confirm the feasibility of targeting mosquito antigens for novel vaccine development, but the "shotgun" approach used probably fails to successfully hit a suitable target antigen with any consistency. The natural variation in mosquito mortality can be countered by rigorous statistical analysis which can identify subtle effects in a very "noisy" experimental system. The midgut is the obvious target organ for anti-mosquito vaccine development and future work will focus on targeting components of this tissue for further immunisations.