A constrained optimization approach to preserving prior knowledge during incremental training

In this paper, a supervised neural network training technique based on constrained optimization is developed for preserving prior knowledge of an input-output mapping during repeated incremental training sessions. The prior knowledge, referred to as long-term memory (LTM), is expressed in the form of equality constraints obtained by means of an algebraic training technique. Incremental training, which may be used to learn new short-term memories (STMs) online, is then formulated as an error minimization problem subject to equality constraints. The solution of this problem is simplified by implementing an adjoined error gradient that circumvents direct substitution and exploits classical backpropagation. A target application is neural network function approximation in adaptive critic designs. For illustrative purposes, constrained training is implemented to update an adaptive critic flight controller, while preserving prior knowledge of an established performance baseline that consists of classical gain-scheduled controllers. It is shown both analytically and numerically that the LTM is accurately preserved while the controller is repeatedly trained over time to assimilate new STMs.     

Self-monitoring: Appraisal and reappraisal.

Theory and research on self-monitoring have accumulated into a sizable literature on the impact of variation in the extent to which people cultivate public appearances in diverse domains of social functioning. Yet self-monitoring and its measure, the Self-Monitoring Scale, are surrounded by controversy generated by conflicting answers to the critical question, Is self-monitoring a unitary phenomenon? A primary source of answers to this question has been largely neglected—the Self-Monitoring Scale's relations with external criteria. The authors propose a quantitative method to examine the self-monitoring literature and thereby address major issues of the controversy. Application of this method reveals that, with important exceptions, a wide range of external criteria tap a dimension directly measured by the Self-Monitoring Scale. The authors discuss what this appraisal reveals about what self-monitoring is and is not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis of metatungstate pillared layered double hydroxides with variable layer composition. Effect of the Mg:Al ratio on the microporous structure

A series of layered double hydroxides (LDHs) pillared with the Keggin ion H₂W₁₂O₄₀⁶⁻ has been synthesized with final Mg:Al ratios of 1.75:1, 2.31:1 and 3.51:1 by ion exchange reaction of the LDH-hydroxide and LDH-adipate precursors. In each case, the pillared product was characterized by specific BET N₂ surface areas of more than 110 m² g⁻¹ and micropore volumes in excess of 0.026 ml g⁻¹. The micropore size distribution plots obtained from the argon adsorption isotherms indicate that the micropore diameters become smaller as the surface charge density of the LDH increases. A study was also performed on each of the LDH precursors in order to determine any problematic steps in the overall synthesis. Significant differences were noticed in the POXRD patterns of the LDH-adipate precursor; these are believed to be due to differences in the orientation and degree of order of the adipate anions in the gallery space of the LDH. It was found that adipate anions orientated with the long axis perpendicular to the inorganic layers were easier to exchange than those where the long axis was aligned parallel to the inorganic layers.     

Individual goals in evolving organizations.

Comments on S. M. Colarelli's (see record 1998-10886-003) discussion of the social-evolutionary perspective of psychological interventions in organizations. The authors clarify and elaborate on Colarelli's argument that the nature of organizational goals makes the relationships between interventions and organizational outcomes problematic and that what may work on one level of hierarchy may not be functional at others. The authors argue that this is true, but it fails to specify a social-evolutionary insight that has profound consequences: Inventions intended to promote organizational goals will be successful only when these interventions also promote the goals of the individuals working within the organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creation of graphene allotropes using patterned defects

Monolithic structures can be built into graphene by the addition and subsequent re-arrangement of carbon atoms. To this end, ad-dimers of carbon are a particularly attractive building block because a number of emerging technologies offer the promise of precisely placing them on carbon surfaces. In concert with the more common Stone-Thrower-Wales defect, repeating patterns can be introduced to create as yet unrealized materials. The idea of building such allotropes out of defects is new, and we demonstrate the technique by constructing two-dimensional carbon allotropes known as haeckelite. We then extend the idea to create a new class of membranic carbon allotropes that we call dimerite, composed exclusively of ad-dimer defects.     

The Decline Of The Political Consensus For Urban Growth: Evidence from Los Angeles

This article explores growth politics in the United States by examining the case of Los Angeles. Recent observers of Los Angeles have noted that growth interests in the city increasingly lack the political coordination to effectively accomplish their projects. One writer has even announced the collapse of the growth machine in the region. Such an assertion is extraordinary, given the power most authors ascribe to growth coalitions and given Los Angeles' strong pro‐growth history. The article presents evidence that the machine has not collapsed, but the political consensus for growth has eroded severely over the past 15 years by a variety of factors. The article then argues that the same general processes that have caused the demise of the growth consensus in Los Angeles are in place in other cities and will likely have similar effects on growth politics there. The article ends by detailing some implications that the end of the growth consensus might have for local politics in the United States.     

Progression into and out of binge drinking among high school students.

The current study examined binge drinking among high school students over an academic year. Adolescent drinkers (N?=?621; 58% female) were grouped into 4 trajectories: drinkers (35%), increasers (14%), decreasers (16%), and persistent binge drinkers (35%). Prospective analyses indicated several factors that predicted escalation and de-escalation of binge drinking. Increasers were more likely to regularly use alcohol and cigarettes at a younger age than drinkers. Compared with decreasers, persistent binge drinkers reported regular alcohol and marijuana use at younger ages. Lower levels of perceived student drinking appeared to be a protective factor for onset of binge drinking. The results highlight the need to study precursors to the naturally occurring fluctuations in binge drinking and suggest factors that may accentuate the risk of binge drinking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)