A Binary Integer Program to Maximize the Agreement Between Partitions

This research note focuses on a problem where the cluster sizes for two partitions of the same object set are assumed known; however, the actual assignments of objects to clusters are unknown for one or both partitions. The objective is to find a contingency table that produces maximum possible agreement between the two partitions, subject to constraints that the row and column marginal frequencies for the table correspond exactly to the cluster sizes for the partitions. This problem was described by H. Messatfa (Journal of Classification, 1992, pp. 5–15), who provided a heuristic procedure based on the linear transportation problem. We present an exact solution procedure using binary integer programming. We demonstrate that our proposed method efficiently obtains optimal solutions for problems of practical size. We would like to thank the Editor, Willem Heiser, and an anonymous reviewer for helpful comments that resulted in improvements of this article.     

Loss of the SKI proto-oncogene in individuals affected with 1p36 deletion syndrome is predicted by strain-dependent defects in Ski-/- mice.

Experiments involving overexpression of Ski have suggested that this gene is involved in neural tube development and muscle differentiation. In agreement with these findings, Ski-/- mice display a cranial neural tube defect that results in exencephaly and a marked reduction in skeletal muscle mass. Here we show that the penetrance and expressivity of the phenotype changes when the null mutation is backcrossed into the C57BL6/J background, with the principal change involving a switch from a neural tube defect to midline facial clefting. Other defects, including depressed nasal bridge, eye abnormalities, skeletal muscle defects and digit abnormalities, show increased penetrance in the C57BL6/J background. These phenotypes are interesting because they resemble some of the features observed in individuals diagnosed with 1p36 deletion syndrome, a disorder caused by monosomy of the short arm of human chromosome 1p (refs. 6-9). These similarities prompted us to re-examine the chromosomal location of human SKI and to determine whether SKI is included in the deletions of 1p36. We found that human SKI is located at distal 1p36.3 and is deleted in all of the individuals tested so far who have this syndrome. Thus, SKI may contribute to some of the phenotypes common in 1p36 deletion syndrome, and particularly to facial clefting.     

Integer Programming Methods for Seriation and Unidemensional Scaling of Proximity Matrices: A Review and Some Extensions

L ₁-norm are also presented. I conclude that the computational scaling problems depends largely on the criterion of interest, with unidimensional scaling problems depends largely on the criterion of interest, with unidimensional scaling in the L ₁-norm being especially challenging.     

The international electrical units: a failure in standardisation?

The ‘international’ electrical units, initially defined by the International Electrical Congress of Chicago in 1893, represented a major step forward in international electrical standardisation. Yet they were flawed both theoretically and technically, were adopted inconsistently in different countries and were soon subject to criticism and revision. This paper addresses the extent to which the international units—notwithstanding their flaws—were in fact adequate for the needs of engineering, commerce and science at the time, and concludes that the practical position was actually very satisfactory. It also addresses how the international electrical units came in to being, in the context of alternative philosophies of the nature of the standardisation process—that it can be essentially central or local. The central influence on the international units was the series of international electrical congresses of the late nineteenth century, which I conclude were a highly unsatisfactory mechanism, responsible for many of the weaknesses in the resulting standards. In contrast, I argue that it was local influences, the networks of scientists and standards laboratories that defined and maintained the standards, which gave them their strength.     

Time-series forecasting of the German unemployment rate

The purpose of the paper is to investigate the accuracy of forecasts derived from univariate and multivariate time-series models. An iterative method to adjust for impact assessment in univariate ARIMA models is discussed and illustrated for the German unemployment rate. Finally, we also examine the pros and cons of the impact assessment model in comparison with VAR models.