Maximizing the length of a success run for many-armed bandits

One of a number of Bernoulli processes is selected at each of a number of stages. A success at stage i is worth α_i and the problem is to maximize the expected payoff before the first failure. Results of Berry and Viscusi (1981) are generalized. In particular, we show that there is always an optimal strategy that uses a single process exclusively and indefinitely whenever the arms are independent and the discount sequence (α₁, α₂,…) is superregular. There is not always a similar reduction in the number of strategies when the discount sequence is not superregular.     

Vibration of cylindrical shells of bimodulus composite materials

A theory is formulated for the small amplitude free vibration of thick, circular cylindrical shells laminated of bimodulus composite materials, which have different elastic properties depending upon whether the fiber-direction strain is tensile or compressive. The theory used is the dynamic, shear deformable (moderately thick shell) analog of the Sanders best first approximation thin shell theory. By means of tracers, the analysis can be reduced to that of various simpler shell theories, namely Love's first approximation, and Donnell's shallow shell theory. As an example of the application of the theory, a closed form solution is presented for a freely supported panel or complete shell. To validate the analysis, numerical results are compared with existing results for various special cases. Also, the effects of the various shell theories, thickness shear flexibility, and bimodulus action are investigated.     

Transformation of “Masked” 1,3-Diols of 1,2-O-Isopropylidene-α-D-Erythro-Hexofuranose into Acyclic Forms. Chirons for Amphotericin B

3,5-Dideoxy-1,2-O-isopropylidene-α-D-erythro-hexofuranose 1 was readily converted to dithianyl amide 8, which is a convenient acyclic form of 1,3-diol, in high yield.     

Direct measurement of attractive van der Waals' forces between regenerated cellulose surfaces in an aqueous environment

The interaction between cellulose surfaces is of fundamental interest in various natural and industrial systems. In this study, we describe the first direct measurements of an attractive van der Waals-type interaction between cellulose surfaces under aqueous conditions. An atomic force microscope, operating in colloidal probe mode, has been used to measure these interactions. The interaction between the cellulose surfaces is monotonically attractive at all surface separations. This long-range attractive interaction can be satisfactorily fitted with a Hamaker constant of 3.5 x 10-21 J.     

CYBERLAB: today’s technology building the future

The availability of a large number of Internet connections creates a new attitude of the users toward society in general and information accessibility and supply in particular. This also includes medical services, especially those that are thriving on measurements such as diagnostic services. Medical laboratories and biometrical departments are suited very well to data/information exchange through web-based technologies. First of all, the location of the actual measurement does not correlate with the location of use of such information (virtual laboratory). Secondly, the time and number of people interested in the data/information obtained are not well defined and vary over time (knowledge factory). So the Internet and web-based technologies are supposed to help out in the order entry, report, and consultation stages of diagnostic services request and provision. Here we describe a pilot study to implement and evaluate such a future-directed tool (i.e, CyberLab from MIPS).Presented at the 8th Conference on Quality in the Spotlight, 17–18 March 2003, Antwerp, Belgium