A vibrotactile approach to tactile rendering

While moving our fingertip over a fine surface we experience a sensation that gives us an idea of its properties. A satisfactory simulation of this feeling is still an unsolved problem. In this paper, we describe a rendering strategy based on vibrations that play an important role in the tactile exploration of fine surfaces. To produce appropriate excitation patterns we use an array of vibrating contactor pins. Similar to the colour model in computer graphics, we simulate arbitrary vibrations as a superposition of only two sinewaves. Each sinewave is intended for the excitation of a specific population of mechanoreceptors. We carried out first tests of our rendering strategy on Brownian surfaces of different fractal dimensions.     

The Importance of Income and Housing Wealth Constraints for Future Residential Mobility

This paper investigates to what extent the mark-up on the lending rate for mortgages depends on expected prepayment. It identifies the effect of the risk of expected prepayment by using a unique dataset of Dutch borrowers insured against default. It is argued that expected prepayment is mainly caused by expected residential mobility of the borrower, which might be due to a change of the value of the collateral or because of a change of income of the borrower. The estimates indicate that lenders require a higher mark-up on the lending rate from households with a lower liquidity constraint, while the collateral constraint has a very limited influence on the mark-up. Thus, it appears that lenders take into account of the possibility that future income shocks may improve the relative position of households in the housing market.     

Mechanical Characterization of Thin Films by Use of Atomic Force Acoustic Microscopy

The atomic force acoustic microscopy (AFAM) technique has been used to determine elastic properties of films with thicknesses decreasing from several hundreds of nanometers to several nanometers. It has been shown that metal films as thin as 50 nm can be characterized directly without the need to consider the influence of the substrate. For films with thicknesses ranging from about 30 to 50 nm, measurement parameters can be chosen such as to allow characterization of the elastic properties of either the film or the film–substrate interface. This attribute has been combined with the ability of the method to obtain qualitative stiffness images to show variations in the film–substrate adhesion. The AFAM technique has been also used to determine the indentation modulus of thin films of silicon oxide with thicknesses ranging from 7 to 28 nm. In this case, elastic properties of the substrate had to be considered. The examples of the applications of the AFAM method reported here for characterization of elastic properties of very thin films have shown that this technique has the lateral and depth resolution required to characterize the very thin films used nowadays in microelectronics industry.     

The CPLEAR electromagnetic calorimeter

A large-acceptance lead/gas sampling electromagnetic calorimeter (ECAL) was constructed for the CPLEAR experiment to detect photons from decays of π⁰s with momentum p_π⁰ ≤ 800 MeV/c. The main purpose of the ECAL is to determine the decay vertex of neutral-kaon decays K⁰ → π⁰π⁰ → 4γ and K⁰ → π⁰π⁰π⁰ → 6γ. This requires a position-sensitive photon detector with high spatial granularity in r−, −, and z−coordinates. The ECAL - a barrel without end-caps located inside a magnetic field of 0.44 T - consists of 18 identical concentric layers. Each layer of 1/3 radiation length (X₀) contains a converter plate followed by small cross-section high-gain tubes of 2640 mm active length which are sandwiched by passive pick-up strip plates. The ECAL, with a total of 6X₀ has an energy resolution of and a position resolution of 4.5 mm for the shower foot. The shower topology allows separation of electrons from pions. The design, construction, read-out electronics, and performance of the detector are described.     

An Input/Output Control System For The Dynamic Job Shop

A combined input/output control system is presented for periodically determining the set of jobs to be released (input variables) and the capacities of processing centers (output variables) in the dynamic job shop, so that a composite cost function is minimized. An interactive heuristic optimizing algorithm incorporating a 0-1 linear mixed integer program is formulated. The resulting control system is compared by simulation with an alternate system for which only input is subject to control. Significant improvements are obtained for most performance measures evaluated.