STANDARDS FOR USER-DRIVEN APPLICATIONS DEVELOPMENT

Users may now be more proficient in developing their own applications, but they aren't equally knowledgeable about the importance of using and following computer standards. Creating these standards is still the job of IS staff members, who should keep in mind that users are willing to use standards if they meet the particular needs of the various user departments.     

Solving #SAT using vertex covers

We propose an exact algorithm for counting the models of propositional formulas in conjunctive normal form. Our algorithm is based on the detection of strong backdoor sets of bounded size; each instantiation of the variables of a strong backdoor set puts the given formula into a class of formulas for which models can be counted in polynomial time. For the backdoor set detection we utilize an efficient vertex cover algorithm applied to a certain “obstruction graph” that we associate with the given formula. This approach gives rise to a new hardness index for formulas, the clustering-width. Our algorithm runs in uniform polynomial time on formulas with bounded clustering-width. It is known that the number of models of formulas with bounded clique-width, bounded treewidth, or bounded branchwidth can be computed in polynomial time; these graph parameters are applied to formulas via certain (hyper)graphs associated with formulas. We show that clustering-width and the other parameters mentioned are incomparable: there are formulas with bounded clustering-width and arbitrarily large clique-width, treewidth, and branchwidth. Conversely, there are formulas with arbitrarily large clustering-width and bounded clique-width, treewidth, and branchwidth.     

Molecular dynamics-based refinement of nanodiamond size measurements obtained with dynamic light scattering

The determination of particle size by dynamic light scattering uses the Stokes–Einstein relation, which can break down for nanoscale objects. Here, we employ a molecular dynamics simulation of fully solvated 1–5 nm carbon nanoparticles for the refinement of the experimental data obtained for nanodiamonds in water by using dynamic light scattering. We performed molecular dynamics simulations in differently sized boxes and calculated nanoparticles diffusion coefficients using the velocity autocorrelation function and mean-square displacement. We found that the predictions of the Stokes–Einstein relation are accurate for nanoparticles larger than 3 nm while for smaller nanoparticles the diffusion coefficient should be corrected and different boundary conditions should be taken into account.     

Integrating IS Disciplines into End-User Training

Abstract

In addition to software training, users need to learn systems analysis concepts and development techniques that will enable them to develop better and more reliable end-user applications. IS managers should realize that this type of IS-sponsored training not only improves the users’ productivity but the IS staffs as well.     

Stabilization of symmetric formations to motion around convex loops

We provide a cooperative control algorithm to stabilize symmetric formations to motion around closed curves suitable for mobile sensor networks. This work extends previous results for stabilization of symmetric circular formations. We study a planar particle model with decentralized steering control subject to limited communication. Because of their unique spectral properties, the Laplacian matrices of circulant graphs play a key role. We illustrate the result for a skewed superellipse, which is a type of curve that includes circles, ellipses, and rounded parallelograms.     

Computations with quasiseparable polynomials and matrices

In this paper, we survey several recent results that highlight an interplay between a relatively new class of quasiseparable matrices and univariate polynomials. Quasiseparable matrices generalize two classical matrix classes, Jacobi (tridiagonal) matrices and unitary Hessenberg matrices that are known to correspond to real orthogonal polynomials and Szegö polynomials, respectively. The latter two polynomial families arise in a wide variety of applications, and their short recurrence relations are the basis for a number of efficient algorithms. For historical reasons, algorithm development is more advanced for real orthogonal polynomials. Recent variations of these algorithms tend to be valid only for the Szegö polynomials; they are analogues and not generalizations of the original algorithms.     

Synaptic proteome changes in the superior frontal gyrus and occipital cortex of the alcoholic brain

Cognitive deficits and behavioral changes that result from chronic alcohol abuse are a consequence of neuropathological changes that alter signal transmission through the neural network. To focus on the changes that occur at the point of connection between the neural network cells, synaptosomal preparations from post‐mortem human brain of six chronic alcoholics and six non‐alcoholic controls were compared using 2‐D differential in‐gel electrophoresis (DIGE). Functionally affected and spared regions (superior frontal gyrus, SFG, and occipital cortex, OC, respectively) were analyzed from both groups to further investigate the specific pathological response that alcoholism has on the brain. Forty‐nine proteins were differentially regulated between the SFG of alcoholics and the SFG of controls and 94 proteins were regulated in the OC with an overlap of 23 proteins. Additionally, the SFG was compared to the OC within each group (alcoholics or controls) to identify region‐specific differences. A selection was identified by MALDI‐TOF mass spectrometry revealing proteins involved in vesicle transport, metabolism, folding and trafficking, and signal transduction, all of which have the potential to influence synaptic activity. A number of proteins identified in this study have been previously related to alcoholism; however, the focus on synaptic proteins has also uncovered novel alcoholism‐affected proteins. Further exploration of these proteins will illuminate the mechanisms altering synaptic plasticity, and thus neuronal signaling and response, in the alcoholic brain.     

Nonlinear gliding stability and control for vehicles with hydrodynamic forcing

This paper presents Lyapunov functions for proving the stability of steady gliding motions for vehicles with hydrodynamic or aerodynamic forces and moments. Because of lifting forces and moments, system energy cannot be used as a Lyapunov function candidate. A Lyapunov function is constructed using a conservation law discovered by Lanchester in his classical work on phugoid-mode dynamics of an airplane. The phugoid-mode dynamics, which are cast here as Hamiltonian dynamics, correspond to the slow dynamics in a multi-time-scale model of a hydro/aerodynamically-forced vehicle in the longitudinal plane. Singular perturbation theory is used in the proof of stability of gliding motions. As an intermediate step, the simplifying assumptions of Lanchester are made rigorous. It is further shown how to design stabilizing control laws for gliding motions using the derived function as a control Lyapunov function and how to compute the corresponding regions of attraction.     

Parent-Infant Synchrony and the Social-Emotional Development of Triplets.

To study the social-emotional development of triplets, 23 sets of triplets, 23 sets of twins, and 23 singleton infants (N=138) were followed from birth to 2 years. Maternal depression and social support were assessed in the postpartum period, mother-infant and father-infant interaction and the home environment were observed at 3 months, a separation-reunion episode and a maternal interview were conducted at 12 months, and infant behavior problems were evaluated at 24 months. Lower parent-infant synchrony was observed for triplets. Triplets showed less distress during maternal separation and less approach at reunion. Mothers reported lower adjustment and differentiation among siblings for triplets than for twins. Higher internalizing problems were reported for triplets, and the triplet with intrauterine growth retardation showed the poorest outcomes. Behavior problems were predicted by medical risk, maternal depression, parent-infant synchrony, infant approach, and mother adjustment. Discussion focuses on developmental risk when the exclusivity of the parent-infant relationship is compromised. (PsycINFO Database Record (c) 2010 APA, all rights reserved)