Hydrocarbon field size distributions: a case study in mixed integer nonlinear programming

Of key importance to oil and gas companies is the size distribution of fields in the areas that they are drilling. Recent arguments suggest that there are many more fields yet to be discovered in mature provinces than had previously been thought because the underlying distribution is monotonic not peaked. According to this view the peaked nature of the distribution for discovered fields reflects not the underlying distribution but the effect of economic truncation. This paper contributes to the discussion by analysing up-to-date exploration and discovery data for two mature provinces using the discovery-process model, based on sampling without replacement and implicitly including economic truncation effects. The maximum likelihood estimation involved generates a high-dimensional mixed-integer nonlinear optimization problem. A highly efficient solution strategy is tested, exploiting the separable structure and handling the integer constraints by treating the problem as a masked allocation problem in dynamic programming.

On Hamilton cycles in locally connected graphs with vertex degree constraints

It is shown that every connected, locally connected graph with the maximum vertex degree Δ(G)=5 and the minimum vertex degree δ(G)3 is fully cycle extendable. For Δ(G)4, all connected, locally connected graphs, including infinite ones, are explicitly described. The Hamilton Cycle problem for locally connected graphs with Δ(G)7 is shown to be NP-complete

Narrating the archive and archiving narrative: the electronic book and the logic of the index

The creation of my hypermedia work Index of Love, which narrates a love story as an archive of moments, images and objects recollected, also articulated for me the potential of the book as electronic text. The book has always existed as both narrative and archive. Tables of contents and indexes allow the book to function simultaneously as linear narrative and non-linear, searchable database. The book therefore has more in common with the so-called 'new media' of the 21st century than it does with the dominant 20th century media of film, video and audiotape, whose logic and mode of distribution are resolutely linear. My thesis is that the non-linear logic of new media brings to the fore an aspect of the book - the index - whose potential for the production of narrative is only just beginning to be explored. When a reader/user accesses an electronic work, such as a website, via its menu, they simultaneously experience it as narrative and archive. The narrative journey taken is created through the menu choices made. Within the electronic book, therefore, the index (or menu) has the potential to function as more than just an analytical or navigational tool. It has the potential to become a creative, structuring device. This opens up new possibilities for the book, particularly as, in its paper based form, the book indexes factual work, but not fiction. In the electronic book, however, the index offers as rich a potential for fictional narratives as it does for factual volumes. [ABSTRACT FROM AUTHOR]