Resistance to change: Developing an individual differences measure.

The Resistance to Change Scale was designed to measure an individual's dispositional inclination to resist changes. In Study 1, exploratory analyses indicated 4 reliable factors: Routine Seeking, Emotional Reaction to Imposed Change, Cognitive Rigidity, and Short-Term Focus. Studies 2, 3. and 4 confirmed this structure and demonstrated the scale's convergent and discriminant validities. Studies 5. 6. and 7 demonstrated the concurrent and predictive validities of the scale in 3 distinct contexts. The scale can be used to account for the individual-difference component of resistance to change and to predict reactions to specific change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cause of the grey discoloration of PET prepared by the use of antimony-catalysts

Heating three antimony catalysts with several glycols and other model compounds in open and sealed vessels with various degrees of oxygen availability was followed by analyses of the volatile products in the head-space and of the nonvolatile products. Bis(hydroxyethylene terephthalate)(Bis-HET) and terephthalic acid (TA) plus ethylene glycol (EG) were separately polymerized to poly(ethylene terephthalate)(PET) and TA plus triethylene glycol (TEG) was polymerized to poly(triethyleneglycol terephthalate) (PTEGT). Analyses of the polymers and of the model compounds revealed that: (1) Free glycols or the glycolate moieties in polyesters degrade upon heating in the presence of oxygen to produce equal amounts of CO and CO₂. (2) In the presence of Sb(III) species, the CO oxidizes to CO₂ at elevated temperatures with the concomitant reduction of Sb(III) to very fine black particles of the elemental Sb(O). This is the cause for the grey discoloration of PET made with Sb-catalysts. The redox reaction starts at about 200°C and is fully dominant at about 235°C and above. (3) At temperatures lower than ?200°C, the Sb(III) usually converts to the white Sb₂O₃ and the CO does not oxidize the CO₂.     

Exploration Strategies for Model-based Learning in Multi-agent Systems: Exploration Strategies

An agent that interacts with other agents in multi-agent systems can benefit significantly from adapting to the others. When performing active learning, every agent's action affects the interaction process in two ways: The effect on the expected reward according to the current knowledge held by the agent, and the effect on the acquired knowledge, and hence, on future rewards expected to be received. The agent must therefore make a tradeoff between the wish to exploit its current knowledge, and the wish to explore other alternatives, to improve its knowledge for better decisions in the future. The goal of this work is to develop exploration strategies for a model-based learning agent to handle its encounters with other agents in a common environment. We first show how to incorporate exploration methods usually used in reinforcement learning into model-based learning. We then demonstrate the risk involved in exploration—an exploratory action taken by the agent can yield a better model of the other agent but also carries the risk of putting the agent into a much worse position.We present the lookahead-based exploration strategy that evaluates actions according to their expected utility, their expected contribution to the acquired knowledge, and the risk they carry. Instead of holding one model, the agent maintains a mixed opponent model, a belief distribution over a set of models that reflects its uncertainty about the opponent's strategy. Every action is evaluated according to its long run contribution to the expected utility and to the knowledge regarding the opponent's strategy. Risky actions are more likely to be detected by considering their expected outcome according to the alternative models of the opponent's behavior. We present an efficient algorithm that returns an almost optimal exploration plan against the mixed model and provide a proof of its correctness and an analysis of its complexity.We report experimental results in the Iterated Prisoner's Dilemma domain, comparing the capabilities of the different exploration strategies. The experiments demonstrate the superiority of lookahead-based exploration over other exploration methods.     

LEARNING OF RESOURCE ALLOCATION STRATEGIES FOR GAME PLAYING

Human chess players exhibit a large variation in the amount of time they allocate for each move. Yet, the problem of devising resource allocation strategies for game playing has not received enough attention. In this paper we present a framework for studying resource allocation strategies. We define allocation strategy and identify three major types of strategies: static, semi-dynamic, and dynamic. We then describe a method for learning semi-dynamic strategies from self-generated examples. We present an algorithm for assigning classes to the examples based on the utility of investing extra resources. The method was implemented in the domain of checkers, and experimental results show that it is able to learn strategies that improve game-playing performance.     

Novel low refractive index self-cross-linking fluoroterpolymers with very low surface tension and good adhesion to substrates

A novel family of fluoroterpolymers was prepared, containing perfluoroalkylethyl methacrylate (PFAEM), methacrylic acid (MAA), and 2-hydroxyethyl methacrylate (2-HEM) residues. The refractive index of the fluoroterpolymers is in the range of 1.3675 ≤ n ≤ 1.4275. The surface tension of cured thin films falls in the interval from 15 mN/m to as low as 8 mN/m. Upon heating, these polymers undergo thermally initiated self-crosslinking and develop tenacious bonding to substrates. The associated chemical reactions and products were identified by IR spectroscopy and some thermogravimetric scans. The spectra indicate that the reaction products are ester and anhydride groups. In general, the formation of esters occurs more rapidly and requires lower temperatures (≥ 110°C) than does the formation of anhydrides. Prolonged heating, especially at higher temperatures (≤ 150°C), favors the formation of anhydrides. When the molar ratio of MAA to 2-HEM is substantially larger than 1.0, the formation of anhydride is favored; when the ratio is 1 : 1, the formation of ester is favored; and when the molar ratio is much smaller than 1.0, the rate of formation of both esters and anhydrides is greatly reduced. In the case of the fluoroterpolymers, the formed esters and anhydrides essentially originate exclusively from the MAA and 2-HEM and seem not to involve any attack on the PFAEM residues. Only after very long heating at the higher temperatures employed, some loss of C? F band intensity was noted. In a copolymer of PFAEM and MAA, a substantial and rapid attack by the acid on the ester group in the PFAEM residues takes place under relatively mild conditions. Such and more drastic conditions appear not to affect at all a homopolymer of PFAEM alone. This suggests that in the fluoroterpolymers the more polar MAA and 2-HEM tend to aggregate close together, so that, when heated, they preferentially react with each other, forming both esters and anhydrides. In the absence of 2-HEM, the MAA may react with itself or with PFAEM, producing only anhydride groups. Both esters and anhydrides may be intermolecular and/or intramolecular, resulting in a cross-linked system in which the cross-link concentration is directly related to the combined amount of ester and anhydride groups. © 1993 John Wiley & Sons, Inc.     

Providing consumers with information about the quality of health plans: the Consumer Assessment of Health Plans demonstration in Washington State

BACKGROUND: In 1995 the Agency for Health Care Policy and Research began a five-year project, Consumer Assessment of Health Plans (CAHPS), to create instruments to collect data from consumers about their health care experiences, to develop sophisticated methods to convey these data to consumers, and to evaluate the value of these data to consumers who are selecting health plans. Results were obtained from one of the first CAHPS demonstration sites, the Washington State Health Care Authority. METHODS: The survey was distributed in May-June 1997 to 15,885 enrollees in 20 health plans; 8,204 (51.6%) surveys were completed. Survey results were summarized in a report that described the performance of plans, which was distributed to 97,000 enrollees, and reactions to the report were obtained from more than 1,500 individuals. RESULTS: Nearly everyone who was mailed the report said they saw it. A large proportion said they read most or all of it, and most thought the report was easy to understand, contained information needed to rate plans, and was helpful to learning about differences between plans. Those who used the CAHPS performance report were more likely to switch plans and to report that they were confident they had selected the best plan for their situation. DISCUSSION: The study was unique in that it attempted to evaluate whether employees read the performance report, how they reacted to it, and whether reading it influenced their decision to switch plans or their confidence that they had selected a suitable plan. Choosing a new plan probably stimulated more intense scrutiny of the report than not anticipating switching.