Nano-texturing of magnetic recording sliders via laser ablation

To increase the storage density of hard disk drives, the flying height of the slider needs to be reduced to <10 nm. This requires super-smooth surfaces of the disk and slider. As the roughness decreases, stiction and adhesion are found to increase substantially leading to failures of the head/disk interface. Texturing the slider surface is a well-known approach to this issue. In this study we investigated laser ablation as a potential process for texturing magnetic recording sliders. It was found that straight laser machining caused unwanted re-deposition of material. These deposits could be significantly reduced by using a chemical etching enhanced laser process.     

State estimation in high-mix semiconductor manufacturing

The traditional way of state estimation in semiconductor manufacturing, known as “threaded” state estimation, segregates the process data into different bins and uses the ones that match the current event of the specific context information (such as tools, layers, products) to update the process state. The limitation of threaded state estimation is that a narrowly defined process stream can result in too many different threads and insufficient data for each thread. This limitation becomes more severe in high-mix manufacturing, where there can be many products and many tools. Hence there is great interest in estimation methods that utilize all available data in the analysis. In this work, the characteristics inherent in state estimation of high-mix semiconductor manufacturing processes are analyzed, and a general framework is introduced for the non-threaded state estimation methods, i.e., state estimation without segregating the process data into different bins. The framework is based on the best linear unbiased estimate (BLUE) of a simplified stationary singular Gauss–Markov process, and non-threaded state estimation methods based on the Kalman filter, least squares and recursive least squares (RLS) are analyzed using the general framework. Simulation examples are presented to illustrate the equivalence between different algorithms. As real processes are rarely stationary, modifications to the Kalman filter and RLS are discussed. We show that in non-threaded state estimation, how to regulate the estimate covariance plays a significant role in estimation performance. To handle nonstationary disturbances that often occur in semiconductor processes, Bayesian-enhanced adaptive versions of the Kalman filter and RLS are proposed. Both simulated and industrial nonstationary processes are used to demonstrate the effectiveness of the proposed adaptive methods.     

A PC-based architecture for parameter analysis of vector-controlled induction motor drive

In this article a methodology for constructing a user interface for system control and data acquisition of a drive which is suitable for three-phase induction motors (3?IM) is presented. The entire hardware implementation is shown, including power and digital stages. Communication between the computer and the controller is engaged in order to enhance an analysis of power quality, adjust the controller parameters for tuning the flux and speed loops, and performance of the embedded algorithm. USB and Ethernet protocols have been put into operation in the user front-end because a high speed sample frequency is required in order to guarantee the real-time operation of the whole system. A software interface is developed using LabVIEW environment enabling features not only as filtering signals of phase voltage and current but also power spectrum measurements. Vector-controlled drive is programmed on a digital signal processor (DSP) in order to ensure efficient use of energy in the power stage and proper tracking of the reference at low and high speeds.     

Seeing size and feeling weight: the size-weight illusion in natural and virtual reality

OBJECTIVE: We experimentally tested the degree that the size-weight illusion depends on perceptual conditions allowing the observer to assume that both the visual and the kinesthetic stimuli of a weight seen and lifted emanate from the same object. We expected that the degree of the illusion depended on the "realism" provided by different kinds of virtual reality (VR) used when the weights are seen in virtual reality and at the same time lifted in natural reality. BACKGROUND: Welch and Warren (1980) reported that an intermodal influence can be expected only if perceptual information of different modalities is compellingly related to only one object. METHOD: Objects of different sizes and weights were presented to 50 participants in natural reality or in four virtual realities: two immersive head-mounted display VRs (with or without head tracking) and two nonimmersive desktop VRs (with or without screening from input of the natural environment using a visor). The objects' heaviness was scaled using the magnitude estimation method. RESULTS: Data show that the degree of the illusion is largest in immersive and lowest in nonimmersive virtual realities. CONCLUSION: The higher the degree of the illusion is, the more compelling the situation is perceived and the more the observed data are in correspondence with the data predicted for the illusion in natural reality. This shows that the kind of mediating technology used strongly influences the presence experienced. APPLICATION: The size-weight illusion's sensitivity to conditions that affect the sense of presence makes it a promising objective presence measure.     

Metacomputing across intercontinental networks

An intercontinental network of supercomputers spanning more than 10 000 miles and running challenging scientific applications was realized at the Supercomputing ’99 (SC99) conference in Portland, OR using PACX-MPI and ATM PVCs. In this paper, we describe how we constructed the heterogeneous cluster of supercomputers, the problems we confronted in terms of multi-architecture and the way several applications handled the specific requirements of a metacomputer.     

The Braun-Falco-Marghescu syndrome, contribution to congenital poikiloderma

Braun-Falco together with Marghescu described 1965 for the first time the clinical picture of bullous congenital poikilodermia. In reviewing 15 cases of the literature and one own case this disease is discussed here as an own nosological entity within the congenital poikilodermias and it is suggested to use the designation "Braun-Falco-Marghescu-Syndrome" according to the first describers.     

The interplay of memory and judgment processes in effects of aging on hindsight bias.

Hindsight bias is the phenomenon that after people are presented with the correct answer to a question, their judgment regarding their own past answer to this question is biased toward the correct answer. In three experiments, younger and older adults gave numerical responses to general-knowledge questions and later attempted to recall their responses. For some questions, the correct answer was provided during recall (Experiment 1) or before recall (Experiments 2 and 3). Multinomial model-based analyses show age differences in both recollection bias and reconstruction bias when the correct judgment was in working memory during the recall phase. The authors discuss implications for theories of cognitive aging and theories of hindsight bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Material Control System for the Manufactured Housing Industry

A manufactured home is a factory-built house constructed in a controlled factory environment according to federal standards known as the Department of Housing and Urban Development (HUD) code. The manufactured home shares approximately 20% of the total housing units in the United States and plays an important role in providing affordable housing. However, in terms of material engineering, advanced techniques are scarcely used in the manufactured housing (MH) industry. The current material flow and control systems are characterized as independent demand systems that are based on the personal experience of the material managers. Although independent inventory control systems are widely used in many manufacturing industries, these systems lead to a large amount of inventory and have many drawbacks for the MH industry. On the other hand, dependent inventory systems can reduce unfavorable inventory levels using new techniques and present substantial benefits for the MH industry. This paper applies lean inventory control systems and supply chain management techniques to the current systems of the MH industry and proposes a new framework of material control systems as one of the system management tools.     

Towards Efficient Execution of MPI Applications on the Grid: Porting and Optimization Issues

The message passing interface (MPI) is a standard used by many parallel scientific applications. It offers the advantage of a smoother migration path for porting applications from high performance computing systems to the Grid. In this paper Grid-enabled tools and libraries for developing MPI applications are presented. The first is MARMOT, a tool that checks the adherence of an application to the MPI standard. The second is PACX-MPI, an implementation of the MPI standard optimized for Grid environments. Besides the efficient development of the program, an optimal execution is of paramount importance for most scientific applications. We therefore discuss not only performance on the level of the MPI library, but also several application specific optimizations, e.g., for a sparse, parallel equation solver and an RNA folding code, like latency hiding, prefetching, caching and topology-aware algorithms.     

Probabilistic proximity search: Fighting the curse of dimensionality in metric spaces

Proximity searches become very difficult on “high dimensional” metric spaces, that is, those whose histogram of distances has a large mean and/or a small variance. This so-called “curse of dimensionality”, well known in vector spaces, is also observed in metric spaces. The search complexity grows sharply with the dimension and with the search radius. We present a general probabilistic framework applicable to any search algorithm and whose net effect is to reduce the search radius. The higher the dimension, the more effective the technique. We illustrate empirically its practical performance on a particular class of algorithms, where large improvements in the search time are obtained at the cost of a very small error probability.