On techniques for angle compensation in nonideal iris recognition.

The popularity of the iris biometric has grown considerably over the past two to three years. Most research has been focused on the development of new iris processing and recognition algorithms for frontal view iris images. However, a few challenging directions in iris research have been identified, including processing of a nonideal iris and iris at a distance. In this paper, we describe two nonideal iris recognition systems and analyze their performance. The word "nonideal" is used in the sense of compensating for off-angle occluded iris images. The system is designed to process nonideal iris images in two steps: 1) compensation for off-angle gaze direction and 2) processing and encoding of the rotated iris image. Two approaches are presented to account for angular variations in the iris images. In the first approach, we use Daugman's integrodifferential operator as an objective function to estimate the gaze direction. After the angle is estimated, the off-angle iris image undergoes geometric transformations involving the estimated angle and is further processed as if it were a frontal view image. The encoding technique developed for a frontal image is based on the application of the global independent component analysis. The second approach uses an angular deformation calibration model. The angular deformations are modeled, and calibration parameters are calculated. The proposed method consists of a closed-form solution, followed by an iterative optimization procedure. The images are projected on the plane closest to the base calibrated plane. Biorthogonal wavelets are used for encoding to perform iris recognition. We use a special dataset of the off-angle iris images to quantify the performance of the designed systems. A series of receiver operating characteristics demonstrate various effects on the performance of the nonideal-iris-based recognition system.     

Novel combination of orientation measurements and transmission microscopy for experimental determination of grain boundary miller indices in silicon and other semiconductors

The determination of grain boundary planes in multicrystalline material has only been restricted to transmission electron microscope investigations (Jang et al., 1992; Elgat et al., 1985) or to metallograpical investigations of the grain boundary (Randle et al., 1993). The first method is expensive, and both are complex and time consuming in grain boundary preparation. This paper proposes the determination of grain boundary planes in semiconductor wafer by a combined application of Electron Back Scatter Diffraction and Infrared Transmission Microscopy. In particular, the new method is demonstrated with directional solidificated multicrystalline silicon.     

Upper-bound modelization of an ironed three-layered polymer-coated steel strip

Global beverage can and food container consumption is very high, with billions of cans produced annually worldwide. There are several steps in can manufacturing, but ironing is the most crucial. In a previous work (Sellés et al., J Mater Process Technol 202:7–14, 2008), a series of ironing experiments were reported using a new material and an ironing simulator. This material was a three-layered polymer-coated steel, and it was seen that under some process conditions, it survived the ironing process with no damage in any of the three layers. The critical die angle was determined as well as specimen quality surface tests. In this paper, an associated theoretical ironing model is described, using the upper-bound theorem and considering the cases of successful ironing or shaving. It is possible to give insight into how to design a material that irons well. For example, the optimal layer thicknesses are also found.     

Modelling and characterization of AlN-actuated microcantilevers vibrating in the first in-plane mode

The characterization of the first in-plane mode of aluminum nitride-actuated piezoelectric microcantilevers was carried out by using electrical and optical techniques. The top electrode of the cantilever was specifically designed to allow for an efficient electrical actuation of these in-plane modes. In order to confirm the in-plane nature of the modal vibration, the detection of the electrically induced movement was performed optically with the help of a stroboscopic microscope. In parallel, resonances were also measured electrically by means of an impedance analyzer. The quality factor and the resonant frequencies of the in-plane modes were estimated from the corresponding measurement data when applying both detection techniques. Our results show quality factor values as high as 3,000 for the first in-plane mode in air.     

Cover Picture: Closing the Gap Between Self‐Assembly and Microsystems Using Self‐Assembly,Transfer, and Integration of Particles (Adv. Mater. 20/2005)

The cover shows 100 μm diameter glass spheres covered by a grid of hexagonally packed polystyrene beads. Wolf and co‐workers placed the 500 nm diameter polystyrene beads onto the larger spheres using the self‐assembly, transfer, and integration (SATI) process that they report on p. 2438. The cover illustrates the capability of SATI to process uneven surfaces in addition to the planar substrates discussed in the article. The carrier that holds the smaller beads deforms during their transfer onto the larger spheres, so that on the larger spheres patterned “caps” are formed. Using this process, which is compatible with standard microfabrication techniques, a variety of particle assemblies can be achieved.     

Calculating ROI for software product lines

Product line engineering has become an important and widely used approach for efficiently developing portfolios of software products. The idea is to develop a set of products as a single, coherent development task from a core asset base (sometimes called a platform), a collection of artifacts specifically designed for use across a portfolio. This approach produces order-of-magnitude economic improvements compared to one-at-a-time software system development. Because the product line approach isn't limited to specific technical properties of the planned software but rather focuses on economic characteristics, high return on investment has become the anthem of the approach's protagonists. Our software product line cost model can calculate the costs and benefits (and hence the ROI) that we can expect to accrue from various product line development situations. It's also straightforward and intuitive.     

Multisensor approach to determine changes of wetland characteristics in semiarid environments (central Spain)

Saline wetlands in the semiarid environment of Central Spain are fragile and highly dynamic ecosystems that are affected by degradation processes as a result of anthropological influences. An increase in agricultural production has led to the development of large-scale irrigation schemes with overexploitation of groundwater, and with consequent effects on the complex hydrology and associated land use. In this work, data from field, hyperspectral airborne, and multispectral satellite sensors are used in order to determine changes of wetland characteristics over time. The spectra of surface components (soil, vegetation, and salt crusts) were selected from the hyperspectral data and identified as endmembers using a site-specific spectral library. The spectral information contained in these endmembers was extrapolated to a temporal series of broadband multispectral imagery on which spectral unmixing analysis was performed in order to detect changes in the wetland over time. Results showed that the selected wetland components have undergone important changes in both their total area as well as their spatial distribution. These changes are mainly associated with the anthropogenic impact; however, natural influences due to seasonal fluctuations may coincide with the overall changes, although this in general is difficult to determine. Water regulation and agricultural practices directly influence the salinity of the soils and therefore the nature of the hygrophytic vegetation.