Metaphor and philosophy: an encounter with Derrida

This paper presents a critical analysis of the central argument of Derrida's paper 'White Mythology'. The crucial claims are that the concept of metaphor presupposes philosophy, that philosophy presupposes the concept of metaphor, and that philosophy cannot accommodate the concept of metaphor. I offer support for the first two claims, explaining the general kind of view of philosophy and of metaphor which they require, but I argue that even if we grant the first two claims, the concept of metaphor only presents a difficulty for a particular conception of philosophy, rather that philosophy as such

The question of idealism in McDowell

John McDowell has attempted to defend himself against the charge that the view presented in his influential book Mind and World is idealist. This paper argues that in spite of that defence, there is a clear way in which the view does depend on a form of idealism. McDowell is committed to the thought that the world is ‘conceptually organized’. I consider what this means, and argue that, although it does not formally imply idealism, it is only defensible from a broadly idealist view—one which is in fact in tension with important claims made by McDowell in other works

The idea of words as signs

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IMPACTS OF INTERNATIONAL MAIZE BREEDING RESEARCH IN DEVELOPING COUNTRIES, 1966-98

This report, which updates and extends the findings of an earlier CIMMYT study published in 1994, documents the impacts of international maize breeding research in the developing world. Covering the period 1966-98, the report reviews public and private investment in maize breeding research, describes the products of public and private maize breeding programs, estimates farm level adoption of modern varieties (MVs), and estimates the gross value of additional grain production attributable to international breeding efforts. Although private companies have greatly increased their investment in maize breeding research in recent years, public maize breeding programs still play an important role, especially in breeding for subsistence-oriented farmers. Seed sales data show that the maize seed industry in many developing countries has effectively been privatized and that hybrid seed sales now dominate sales of all other seed types. The area planted to MVs continues to expand at an impressive rate. Maize MVs are currently grown on at least 58.8 million ha in developing countries, including at least 21.2 million ha planted to MVs that contain CIMMYT germplasm. The gross value of additional grain production attributable to the adoption of maize MVs in developing countries is estimated to range from US$3.7 million to US$ 11.1 billion per year. Analysis of varietal pedigrees shows that breeders in both the public and private sectors have made extensive use of CIMMYT germplasm. Over 54% of publicly bred MVs released in the developing world since 1966 have contained CIMMYT germplasm. The pedigrees of many privately bred cultivars are confidential, but CIMMYT germplasm was present in 58% of MVs developed by private breeding programs being sold in the late 1990s for which pedigree information is available. The gross benefits attributable to CIMMYT's maize breeding program are estimated to range from US$167 million to US$ 1.5 billion per year.Productivity Analysis,

Building a Driving Simulator as an Electric Vehicle Hardware Development Tool

Driving simulators have been used to support the development of new vehicle systems for many years. The rise of electric vehicles (EVs) as a means of reducing carbon emissions has lead to the emergence of a number of new design challenges related to the performance of EV components and the flow of power under a variety of circumstances. In this paper we describe the integration of an EV drive train test system with a driving simulator to allow the performance of EV systems to be investigated while under the control of real drivers in simulated scenarios. Such a system offers several potential benefits. The performance of EV drive trains can be evaluated subjectively by real world users while the electrical and mechanical properties can be tested under a variety of conditions which would be difficult to replicate using standard drive cycles

Existence and uniqueness theorems for massless fields on a class of spacetimes with closed timelike curves

We study the massless scalar field on asymptotically flat spacetimes with closed timelike curves (CTC's), in which all future-directed CTC's traverse one end of a handle (wormhole) and emerge from the other end at an earlier time. For a class of static geometries of this type, and for smooth initial data with all derivatives in $L_2$ on {\cI}^{-}, we prove existence of smooth solutions which are regular at null and spatial infinity (have finite energy and finite $L_2$-norm) and have the given initial data on \cI^-. A restricted uniqueness theorem is obtained, applying to solutions that fall off in time at any fixed spatial position. For a complementary class of spacetimes in which CTC's are confined to a compact region, we show that when solutions exist they are unique in regions exterior to the CTC's. (We believe that more stringent uniqueness theorems hold, and that the present limitations are our own.) An extension of these results to Maxwell fields and massless spinor fields is sketched. Finally, we discuss a conjecture that the Cauchy problem for free fields is well defined in the presence of CTC's whenever the problem is well-posed in the geometric-optics limit. We provide some evidence in support of this conjecture, and we present counterexamples that show that neither existence nor uniqueness is guaranteed under weaker conditions. In particular, both existence and uniqueness can fail in smooth, asymptotically flat spacetimes with a compact nonchronal region.Comment: 47 pages, Revtex, 7 figures (available upon request

Missing Value Imputation With Unsupervised Backpropagation

Many data mining and data analysis techniques operate on dense matrices or complete tables of data. Real-world data sets, however, often contain unknown values. Even many classification algorithms that are designed to operate with missing values still exhibit deteriorated accuracy. One approach to handling missing values is to fill in (impute) the missing values. In this paper, we present a technique for unsupervised learning called Unsupervised Backpropagation (UBP), which trains a multi-layer perceptron to fit to the manifold sampled by a set of observed point-vectors. We evaluate UBP with the task of imputing missing values in datasets, and show that UBP is able to predict missing values with significantly lower sum-squared error than other collaborative filtering and imputation techniques. We also demonstrate with 24 datasets and 9 supervised learning algorithms that classification accuracy is usually higher when randomly-withheld values are imputed using UBP, rather than with other methods