Just-in-time adaptive disturbance estimation for run-to-run control of semiconductor processes

Run-to-run control is the term used for the application of discrete parts manufacturing control as practiced in the semiconductor industry. This paper presents a new algorithm for use in run-to-run control that has been designed to address some of the challenging issues unique to batch-type manufacturing. Just-in-time adaptive disturbance estimation (JADE) uses recursive weighted least squares parameter estimation to identify the contributions to variation that are dependent upon manufacturing context. The strengths and weaknesses of the JADE algorithm are demonstrated in a series of test cases developed to separate the various disturbances and processing issues a control system would be expected to encounter.     

A studentized permutation test for the non-parametric Behrens-Fisher problem

For the non-parametric Behrens-Fisher problem a permutation test based on the studentized rank statistic of Brunner and Munzel is proposed. This procedure is applicable to count or ordered categorical data. By applying the central limit theorem of Janssen, it is shown that the asymptotic permutational distribution of this test statistic is a standard normal distribution. For very small and very different sample sizes, frequently occurring in medical and biological applications, an extensive simulation study suggests that this permutation test works well for data from several underlying distributions. The proposed test is applied to data from a clinical trial.     

Five traps for consulting psychologists: or, How I learned to take culture seriously.

In this article, the author identifies the major traps that consulting psychologists fall into because they do not take cultural and sociological factors into account when working with complex social systems. Too many of the consulting models coming out of psychology assume that what works at the individual level can be extrapolated to the larger systems level leading to misunderstanding of what is a client system and how to work with groups and organizations (Schein, 1999a, 1999b). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fault tolerant algorithms for heat transfer problems

With the emergence of new massively parallel systems in the high performance computing area allowing scientific simulations to run on thousands of processors, the mean time between failures of large machines is decreasing from several weeks to a few minutes. The ability of hardware and software components to handle these singular events called process failures is therefore getting increasingly important. In order for a scientific code to continue despite a process failure, the application must be able to retrieve the lost data items. The recovery procedure after failures might be fairly straightforward for elliptic and linear hyperbolic problems. However, the reversibility in time for parabolic problems appears to be the most challenging part because it is an ill-posed problem. This paper focuses on new fault-tolerant numerical schemes for the time integration of parabolic problems. The new algorithm allows the application to recover from process failures and to reconstruct numerically the lost data of the failed process(es) avoiding the expensive roll-back operation required in most checkpoint/restart schemes. As a fault tolerant communication library, we use the fault tolerant message passing interface developed by the Innovative Computing Laboratory at the University of Tennessee. Experimental results show promising performances. Indeed, the three-dimensional parabolic benchmark code is able to recover and to keep on running after failures, adding only a very small penalty to the overall time of execution.     

Web networks of the science system: Weighted hubs and authorities

Summary Visualization with the algorithm of BibTechMon provides the out-degree as well as the in-degree. The analysis shows that both frequency and co-occurrences of objects (nodes in the network) support the idea of Kleinberg's algorithm. The analysis of the algorithm shows clearly that strongly linked scores lead the iteration to a convergence and give the highest weights. Therefore BibTechMon visualizes the results well.     

Morphometric assessment of enamel demineralisation from photographs

OBJECTIVES: To investigate the validity and reproducibility of a method of morphometric assessment of enamel demineralisation. METHODS: An in vitro investigation was carried out on 22 human teeth. One investigator coated the crowns of the teeth with an acid-resistant varnish, leaving a small window on the buccal surface. This was incrementally occluded by varnish over a 14-day period, during which the teeth were placed in a demineralising gel at pH 4.5. After varnish removal, a second investigator blindly quantitated the demineralised area by three methods of examination; direct visual, microscopic and from photographs. The microscopic and photographic measurements were carried out using a morphometric assessment with a 121-dot array. Photographs and assessments were repeated after 1 week. The readings were analysed using the kappa statistic, the limits of agreement and the coefficient of repeatability. RESULTS: Photographic assessments demonstrated excellent agreement for grid positioning (kappa > 0.81) and substantial agreement for reading reproducibility (kappa = 0.61-0.80). The coefficients of repeatability were found to be the same for repeat readings of the same slide and the repeated slides (5.0 mm2). They were higher for the microscopic technique (6.8 mm2) and for the direct visual technique (7.8 mm2). The limits of agreement are presented graphically. CONCLUSIONS: The photographic technique used was a reproducible method of measuring artificial enamel demineralisation. Measurement from photographs was more reproducible than direct measurement with the naked eye. Subjectiveness of the index leads to most variation and more objective means of assessing enamel demineralisation need to be found.     

Encapsulation of multi-walled carbon nanotubes with copolymer to disperse in aqueous media

An emulsion-like polymerization technique called admicellar polymerization (AP) was used to encapsulate a thin film of copolymer on the surface of multi-walled carbon nanotubes (MWCNTs). A water-soluble component sodium acrylate and a non-water soluble component methyl methacrylate were used to form thin films of copolymer on multi-walled carbon nanotubes. Various ratios of polymer combinations were formulated on MWCNT’s to understand the stability of polymer composition and surface heterogeneity on MWCNT’s. Encapsulated MWCNTs were characterized using SEM, energy dispersive spectroscopy (EDS), thermal analysis and FT-IR. Analytical studies indicate the formation of copolymer on MWCNTs. Monomer conversion rate and copolymer reactivity ratios were analyzed using high performance liquid chromatography (HPLC) by Fineman-Ross and Kelen-Tüdos methods. The copolymer combination showed an alternating tendency and azeotropic composition at 0.6 acrylate monomer. The encapsulated MWCNTs were stable in aqueous media with onset of aggregate formation beginning at 40 days for the copolymer.     

Combinatorial Particle Patterning

The unique properties of solid particles make them a promising element of micro‐ and nanostructure technologies. Solid particles can be used as building blocks for micro and nanostructures, carriers of monomers, or catalysts. The possibility of patterning different kinds of particles on the same substrate opens the pathway for novel combinatorial designs and novel technologies. One of the examples of such technologies is the synthesis of peptide arrays with amino acid particles. This review examines the known methods of combinatorial particle patterning via static electrical and magnetic fields, laser radiation, patterning by synthesis, and particle patterning via chemically modified or microstructured surfaces.