Organisations going virtual

This paper deals with the different meanings given to the concept of virtual organisation. A typology developed by Campbell, consisting of four forms of virtual organisation, is presented. We illustrate this categorisation with practical examples. We will explain why we use the term virtual organising rather than virtual organisation. Our conclusion is that organisations planning to go virtual have to make technological and organisational decisions that are intertwined at a strategic level, resulting in a specific sociotechnical configuration of virtual organising.     

Posture-based motion planning: Applications to grasping.

This article describes a model of motion planning instantiated for grasping. According to the model, one of the most important aspects of motion planning is establishing a constraint hierarchy—a set of prioritized requirements defining the task to be performed. For grasping, constraints include avoiding collisions with to-be-grasped objects and minimizing movement-related effort. These and other constraints are combined with instance retrieval (recall of stored postures) and instance generation (generation of new postures and movements to them) to simulate flexible prehension. Dynamic deadline setting is used to regulate termination of instance generation, and performance of more than one movement at a time with a single effector is used to permit obstacle avoidance. Old and new data are accounted for with the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biometric perils and patches

Biometrics authentication offers many advantages over conventional authentication systems that rely on possessions or special knowledge. With conventional technology, often the mere possession of an employee ID card is proof of ID, while a password potentially can be used by large groups of colleagues for long times without change. The fact that biometrics authentication is non-repudiable (hard to refute) and, yet, convenient, is among its most important advantages. Biometrics systems, however, suffer from some inherent biometrics-specific security threats. These threats are mainly related to the use of digital signals and the need for additional input devices, though we also discuss brute-force attacks of biometrics systems. There are also problems common to any pattern recognition system. These include “wolves” and “lambs”, and a new group we call “chameleons”. An additional issue with the use of biometrics is the invasion of privacy because the user has to enroll with an image of a body part. We discuss these issues and suggest some methods for mitigating their impact.     

Generating cancelable fingerprint templates

Biometrics-based authentication systems offer obvious usability advantages over traditional password and token-based authentication schemes. However, biometrics raises several privacy concerns. A biometric is permanently associated with a user and cannot be changed. Hence, if a biometric identifier is compromised, it is lost forever and possibly for every application where the biometric is used. Moreover, if the same biometric is used in multiple applications, a user can potentially be tracked from one application to the next by cross-matching biometric databases. In this paper, we demonstrate several methods to generate multiple cancelable identifiers from fingerprint images to overcome these problems. In essence, a user can be given as many biometric identifiers as needed by issuing a new transformation "key". The identifiers can be cancelled and replaced when compromised. We empirically compare the performance of several algorithms such as Cartesian, polar, and surface folding transformations of the minutiae positions. It is demonstrated through multiple experiments that we can achieve revocability and prevent cross-matching of biometric databases. It is also shown that the transforms are noninvertible by demonstrating that it is computationally as hard to recover the original biometric identifier from a transformed version as by randomly guessing. Based on these empirical results and a theoretical analysis we conclude that feature-level cancelable biometric construction is practicable in large biometric deployments     

Positive Affect as Implicit Motivator: On the Nonconscious Operation of Behavioral Goals.

Recent research has revealed that nonconscious activation of desired behavioral states--or behavioral goals--promotes motivational activity to accomplish these states. Six studies demonstrate that this nonconscious operation of behavioral goals emerges if mental representations of specific behavioral states are associated with positive affect. In an evaluative-conditioning paradigm, unobtrusive linking of behavioral states to positive, as compared with neutral or negative, affect increased participants' wanting to accomplish these states. Furthermore, participants worked harder on tasks that were instrumental in attaining behavioral states when these states were implicitly linked to positive affect, thereby mimicking the effects on motivational behavior of preexisting individual wanting and explicit goal instructions to attain the states. Together, these results suggest that positive affect plays a key role in nonconscious goal pursuit. Implications for behavior-priming research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transgenic studies of pain

A revolution in molecular biological technology has allowed, for the first time, the study of pain at the level of the gene. The molecular genetic technique currently garnering the most interest is the use of transgenic mice that either overexpress, or do not express, presumably pain-related proteins. This paper reviews the findings of investigations in which a transgenic mouse has been assessed for nociceptive or analgesic sensitivity. As of this writing, 25 different kinds of mutant mice--lacking neurotrophins and their receptors, peripheral mediators of nociception and hyperalgesia, opioids and their receptors, non-opioid transmitter receptors, and intracellular molecules participating in signal transduction--have been produced and tested on behavioral assays of nociception. Results of these studies have been variously confirmatory, contradictory and enlightening compared to conventional investigations. The advantages and limitations of this approach to pain research are discussed.     

Ground-based zenith sky abundances and in situ gas cross sections for ozone and nitrogen dioxide with the Earth Observing System Aura Ozone Monitoring Instrument

High-accuracy spectral-slit-function calibration measurements, in situ ambient absorption gas cell measurements for ozone and nitrogen dioxide, and ground-based zenith sky measurements with the Earth Observing System Aura Ozone Monitoring Instrument (OMI) flight instrument are reported and the results discussed. For use of high-spectral-resolution gas absorption cross sections from the literature in trace gas retrieval algorithms, accurate determination of the instrument's spectral slit function is essential. Ground-based measurements of the zenith sky provide a geophysical determination of atmospheric trace gas abundances. When compared with other measurements, they can be used to verify the performance of the OMI flight instrument. We show that the approach of using published high-resolution absolute absorption cross sections convolved with accurately calibrated spectral slit functions for OMI compares well with in situ gas absorption cell measurements made with the flight instrument and that use of these convolved cross sections works well for reduction of zenith sky data taken with the OMI flight instrument for ozone and nitrogen dioxide that are retrieved from measured spectra of the zenith sky with the differential optical absorption spectroscopy technique, the same method to be used for the generation of in-flight data products. Finally, it is demonstrated that the spectral stability and signal-to-noise ratio performance of the OMI flight instrument, as determined from preflight component and full instrument tests, are sufficient to meet OMI mission objectives.     

On D-optimality based trust regions for black-box optimization problems

Various sequential derivative-free optimization algorithms exist for solving black-box optimization problems. Two important building blocks in these algorithms are the trust region and the geometry improvement. In this paper, we propose to incorporate the D-optimality criterion, well known in the design of experiments, into these algorithms in two different ways. Firstly, it is used to define a trust region that adapts its shape to the locations of the points in which the objective function has been evaluated. Secondly, it is used to determine an optimal geometry-improving point. The proposed trust region and geometry improvement can both be implemented into existing sequential algorithms.