Perturbed quantization steganography

In this paper, we use the recently proposed wet paper codes and introduce a new approach to passive-warden steganography called perturbed quantization. In perturbed quantization, the sender hides data while processing the cover object with an information-reducing operation that involves quantization, such as lossy compression, downsampling, or A/D conversion. The unquantized values of the processed cover object are considered as side information to confine the embedding changes to those unquantized elements whose values are close to the middle of quantization intervals. This choice of the selection channel calls for wet paper codes as they enable communication with non-shared selection channel. Heuristic is presented that indicates that the proposed method provides better steganographic security than current JPEG steganographic methods. This claim is further supported by blind steganalysis of a specific case of perturbed quantization for recompressed JPEG images.     

Nitsche Type Mortaring for some Elliptic Problem with Corner Singularities

The paper deals with Nitsche type mortaring as a finite element method (FEM) for treating non-matching meshes of triangles at the interface of some domain decomposition. The approach is applied to the Poisson equation with Dirichlet boundary conditions (as a model problem) under the aspect that the interface passes re-entrant corners of the domain. For such problems and non-matching meshes with and without local refinement near the re-entrant corner, some properties of the finite element scheme and error estimates are proved. They show that appropriate mesh grading yields convergence rates as known for the classical FEM in presence of regular solutions. Finally, a numerical example illustrates the approach and the theoretical results. Received July 5, 2001; revised February 5, 2002 Published online April 25, 2002     

Security in the wild: user strategies for managing security as an everyday,practical problem

Ubiquitous and mobile technologies create new challenges for system security. Effective security solutions depend not only on the mathematical and technical properties of those solutions, but also on people’s ability to understand them and use them as part of their work. As a step towards solving this problem, we have been examining how people experience security as a facet of their daily life, and how they routinely answer the question, “is this system secure enough for what I want to do?” We present a number of findings concerning the scope of security, attitudes towards security, and the social and organizational contexts within which security concerns arise, and point towards emerging technical solutions.     

Semiautomated depositor for infrared microspectrometry

The measurement of minute samples is desirable in many areas of research and analysis, including biological, environmental, and forensic sciences. The use of manual solution direct deposition, combined with surface evaporation, is a very useful and convenient method for the transfer of many analytes to a spectroscopic sampling window. For Fourier transform infrared (FT-IR) spectrometric analysis, high quality attenuated total reflection (ATR) and transmission analyses are possible with suitable solution deposits. If the sample area is very small, placement of the analyte deposit on the active area of the sampling accessory must be done carefully. To achieve this, a novel direct deposition system has been developed. This system, a series of valves attached to a glass nebulizer, generates deposits that are reproducible, and placement of the deposits is precise. The valves allow the sample to be loaded, helium airflow to expel the sample, and the nebulizer to be cleaned after deposition. To help contain the sample to a small area once deposition has taken place, a vacuum line is attached to the nebulizer. This simple semiautomated deposition system allows for higher sensitivity and run-to-run reproducibility for minute sample analysis.     

Local anesthetic treatment significantly attenuates acute pain responding but does not prevent the neonatal injury-induced reduction in adult spinal behavioral plasticity.

Recent findings indicate that neonatal injury results in decreased spinal plasticity in adult subjects (E. E. Young, K. M. Baumbauer, A. E. Elliot, & R. L. Joynes, 2007). Previous research has shown that acute manipulations of pain processing (i.e., administration of formalin, carrageenan, capsaicin) result in a loss of spinal behavioral plasticity (A. R. Ferguson, E. D. Crown, & J. W. Grau, 2006). Moreover, neonatal injury results in a lasting reduction in adult spinally mediated plasticity resembling the deficit seen following acute manipulations in adults (E. E. Young et al., 2007). The present study was designed to determine whether the effects of neonatal injury could be prevented by lidocaine administration during the initial healing period. Subjects (injured or uninjured) received lidocaine or saline on 1 of 4 administration schedules (preinjury only, postinjury only, for 24 hr postsurgery, or for 72 hr postsurgery). Results demonstrated that lidocaine administration did not prevent the hypersensitivity and reduced spinal plasticity associated with neonatal injury. This suggests that (a) the mechanisms underlying neonatal injury are independent of peripheral input in the initial healing period and (b) lidocaine is ineffective at preventing long-term spinal plasticity changes following neonatal injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fluoxetine, smoking, and history of major depression: A randomized controlled trial.

The study was a randomized placebo-controlled trial testing whether fluoxetine selectively enhances cessation for smokers with a history of depression. Euthymic smokers with (H+, n = 109) or without (H-, n = 138) a history of major depression received 60 mg fluoxetine or placebo plus group behavioral quit-smoking treatment for 12 weeks. Fluoxetine initially enhanced cessation for H+ smokers (p = .02) but subsequently impaired cessation regardless of depressive history. Six months after quit date, fluoxetine-treated participants were 3.3 times more likely to be smoking (p = .02). Further research is warranted to determine why high-dose fluoxetine produces continuing effects that oppose tobacco abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Treating another's actions as one's own: Children's memory of and learning from joint activity.

Children often overestimate their contribution to collaborative activities. Across 2 studies, the authors investigated whether this memory bias supports internalization of the actions of others in the context of joint exchanges. After taking turns with (high collaborative condition; Studies 1 and 2) or working independently of (low collaborative condition; Study 2) an adult experimenter to create a series of novel toys, children's agent memory and reconstruction ability were assessed. Children in the high collaborative condition but not the low collaborative condition systematically overclaimed the actions of their social partner, more frequently reporting having completed steps performed by the experimenter than vice versa. This "I did it" bias was related to learning performance: high collaborative children outperformed low collaborative children both during an immediate reconstruction task and 4 months later, and the strength of the bias predicted children's independent toy-building accuracy. It is argued that the "I did it" bias may emerge as part of a general process of learning from others and is supported by a common framework for representing self-actions and other actions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Practical and ethical assessment issues in rural, impoverished, and managed care settings.

The rising costs of new psychological tests, increased frequency of test revisions, and difficulty receiving authorization and reimbursement from managed care companies make it increasingly difficult for practitioners to provide the best standard of care to clients when conducting psychological and neuropsychological assessments. Practitioners, especially those in low-income and rural areas, may struggle with handling these practical realities while maintaining ethical standards in conducting psychological assessment. Suggestions for how to manage practical challenges faced by practitioners who provide psychological assessments, such as selecting tests when authorization or reimbursement by a third-party payer is restricted or denied, purchasing psychological tests on a budget, and providing assessments with a limited number of qualified staff are discussed. The authors also provide recommendations for the future prevention of these challenges through work with test developers, test publishing corporations, third-party payers, political action groups, and the psychology profession itself. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optical Frequency Metrology of an Iodine-Stabilized He-Ne Laser Using the Frequency Comb of a Quantum-Interference-Stabilized Mode-Locked Laser

We perform optical frequency metrology of an iodine-stabilized He-Ne laser using a mode-locked Ti:sapphire laser frequency comb that is stabilized using quantum interference of photocurrents in a semiconductor. Using this technique, we demonstrate carrier-envelope offset frequency fluctuations of less than 5 mHz using a 1 s gate time. With the resulting stable frequency comb, we measure the optical frequency of the iodine transition [¹²⁷I₂ R(127) 11-5 i component] to be 473 612 214 712.96 ± 0.66 kHz, well within the uncertainty of the CIPM recommended value. The stability of the quantum interference technique is high enough such that it does not limit the measurements.