Geometric approach to Fletcher's ideal penalty function

Original article can be found at: www.springerlink.com Copyright Springer. [Originally produced as UH Technical Report 280, 1993]In this note, we derive a geometric formulation of an ideal penalty function for equality constrained problems. This differentiable penalty function requires no parameter estimation or adjustment, has numerical conditioning similar to that of the target function from which it is constructed, and also has the desirable property that the strict second-order constrained minima of the target function are precisely those strict second-order unconstrained minima of the penalty function which satisfy the constraints. Such a penalty function can be used to establish termination properties for algorithms which avoid ill-conditioned steps. Numerical values for the penalty function and its derivatives can be calculated efficiently using automatic differentiation techniques.Peer reviewe

Stagnation Point Heat Transfer with Gas Injection Cooling

The present paper deals with an experimental study of the stagnation-point heat transfer to a cooled copper surface with gas injection under subsonic conditions. Test were made with a probe that combined a steady-state water-cooled calorimeter that allows the capability to study convective blockage and to perform heat transfer measurements in presence of gas injection in the stagnation region. The copper probe was pierced by 52 holes, representing 2.4% of the total probe surface. The 1.2 MW high enthalpy plasma wind tunnel was operated at anode powers between 130 and 230 kW and a static pressures from 35 hPa up to 200 hPa. Air, carbon dioxide and argon were injected in the mass flow range 0-0.4 g/s in the boundary layer developed around the 50 mm diameter probe. The measured stagnation-point heat transfer rates are reported and discussed

Theory of phonon-drag thermopower of extrinsic semiconducting single-wall carbon nanotubes and comparison with previous experimental data

A theoretical model for the calculation of the phonon-drag thermopower, $S^{g}$, in degenerately doped semiconducting single-wall carbon nanotubes (SWCNTs) is proposed. Detailed calculations of $S^{g}$ are performed as a function of temperature, tube radius and position of the Fermi level. We derive a simple analytical expression for $S^{g}$ that can be utilized to determine the free carrier density in doped nanotubes. At low temperatures $S^{g}$ shows an activated behavior characteristic of the one-dimensional (1D) character of carriers. Screening effects are taken into account and it is found that they dramatically reduce the magnitude of $S^{g}$. Our results are compared with previous published experimental data in bulk p-doped SWCNT materials. Excellent agreement is obtained in the temperature range 10-200 K for a consistent set of parameters. This is a striking result in view of the complexity of these systems.Comment: 21 pages, 6 figures. This version has been accepted for publication in Phys. Rev.

An Ontology Engineering Approach to User Profiling for Virtual Tours of Museums and Galleries

This paper describes a study of the development of a hierarchical ontology for producing and maintaining personalized profiles to improve the experience of visitors to virtual art galleries and museums. The paper begins by describing some of the features of virtual exhibitions and offers examples of virtual tours that the reader may wish to examine in more detail. The paper then discusses the ontology engineering (OE) approach and domain modelling languages (e.g. KACTUS, SENSUS and METHONTOLOGY). It then follows a basic OE approach to define classes for a cultural heritage virtual tour and to produce a Visitor Profile Ontology that is hierarchical and has static and dynamic elements. It concludes by suggesting ways in which the ontology may be automated to provide a richer, more immersive personalized visitor experience

Seed coat colour development in black beans

Non-Peer ReviewedDry beans come in a wide variety of seed coat patterns and colours and the quality and value of the bean crop is largely determined by appearance and condition of the seed, particularly colour uniformity and stability. In western Canada, black bean is a significant portion of the crop. For some black bean varieties, the seed coat colour does not fully develop until the pod is mature. This may be the result of genotype, or environment, or both. In these cases, harvesting at plant maturity rather than at seed maturity can lead to a non-uniform crop sample in which the black beans are mixed with beans that have a purple or gray tinge. Full expression of seed coat colour is economically important as variable colour development may result in a 2-4 cent per pound discount. Seed coat colour is determined by the presence of anthocyanins and condensed tannins. In this experiment, we examined the timing of pigment deposition in the seed coat in relation to pod maturity for 5 black bean varieties (CDC Expresso, CDC Nighthawk, CDC Jet, AC Black Diamond, and T39) to determine if there is genetic variation for timing of seed coat colour development. If it is under genetic control, we will be able to breed for earlier colour development to ensure full colour expression at plant maturity

Generic model for magnetic explosions applied to solar flares

An accepted model for magnetospheric substorms is proposed as the basis for a generic model for magnetic explosions, and is applied to solar flares. The model involves widely separated energy-release and particle-acceleration regions, with energy transported Alfv\'enically between them. On a global scale, these regions are coupled by a large-scale current that is set up during the explosion by redirection of pre-existing current associated with the stored magnetic energy. The explosion-related current is driven by an electromotive force (EMF) due to the changing magnetic flux enclosed by this current. The current path and the EMF are identified for an idealized quadrupolar model for a flare

e-Tourism and Culture through Virtual Art Galleries: A pilot study of the usability of an interface

Virtual tours of museums and galleries are becoming an increasingly common aspect of e-Tourism marketing. This paper reports on a usability pilot study that analyses the design of icons in a German 3-D virtual art gallery interface. It evaluates the extent to which a sample of typical computer users can interpret the meaning of icons from the interface taken ‘out of context’. This was done by assessing a sample of twenty-one icons representing the ‘action’, ‘information’ and ‘navigation’ functions. An Icon Intuitiveness Test (IIT) was used to measure their Icon Recognition Rate (IRR) and to classify them as ‘identifiable’, ‘mediocre’ or ‘vague’ according to an adapted stereotypy. The IIT results show that the meaning of almost 30% of the icons was misinterpreted or confused, which can seriously compromise the usability of an interface. Based on these findings, recommendations are made for icon redesign and replacement and it is concluded that further research is needed into the ‘learnability’ of icons and users’ understanding of icons in context. It is contended that increased usability leading to an improved user experience can have an economic impact on e-Tourism