A discounted integrated inspection-maintenance model for a single deteriorating production facility

In this paper, we address the problem of determining optimum inspection schedules for a single deteriorating production system with a predetermined replacement cycle. It is assumed that, at different discrete points in time over the fixed planning horizon, the facility is inspected to detect its operating state and then it goes over an imperfect preventive maintenance routine to enhance its operating performance. Moreover, the facility undergoes minimal repair once detected in an “out‐of‐control” state. We also adopt the concept of discounted cash flow analysis to account properly for the effect of time value of money on the inspection policies. Under these settings, we formulate the discounted integrated inspection‐maintenance problem as a dynamic programming model with general time to failure distribution. After illustrating the model with a numerical example, we perform sensitivity analysis to investigate the effects of some input parameters on the expected present worth and the number of inspections.     

Laboratory and self-report assessments of impulsive behavior in adolescent daily smokers and nonsmokers.

This research compared adolescent daily smokers (n = 25) and nonsmokers (n = 26) on different measures of impulsivity. Assessments included question-based measures of delay (DDQ) and probability (PDQ) discounting, a measure of behavioral disinhibition (go-stop task), and a self-report measure of impulsivity (Barratt Impulsiveness Scale-Adolescent). Adolescent smokers were more impulsive on the DDQ and Barratt Impulsiveness Scale--Adolescent but not on the PDQ or the go-stop task. However, there was a significant interaction between smoking status and gender on the go-stop task, with male smokers performing less impulsively on this measure than male nonsmokers--an effect not observed with the female adolescents. These findings indicate that adolescents who smoke cigarettes are more impulsive with respect to some, but not all, types of impulsivity than are adolescents who do not smoke. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

信息完整性缓解权力差距对建议表面采纳的影响

目的本研究根据内隐态度是否改变,将建议采纳(Advice Taking)区分为表面采纳和真实采纳,从权力差距入手探讨其对表面采纳的影响,并考查信息完整性如何降低表面采纳提高真实采纳。方法实验以在校大学生为被试(N=170),将权力差距设为被试内变量,信息完整性为组间变量,随机将被试分为高信息完整性组和低信息完整性组,通过五个决策情境来探讨两个变量对表面采纳的影响。结果分析发现,决策者权力小于建议者时,决策者的建议采纳程度较高,但存在表面采纳现象;决策者与建议者权力接近时,建议采纳程度较低,表面采纳也较低;当信息完整性提高时,表面采纳程度显著降低,真实采纳提高。结论权力差距增大会导致表面采纳;提高信息完整性可降低表面采纳。     

Differential effects on effort discounting induced by inactivations of the nucleus accumbens core or shell.

The authors investigated the contribution of the nucleus accumbens (NAc) core and shell to effort-based decision making using a discounting procedure. Selection of 1 lever delivered a smaller, 2-pellet reward immediately, whereas the other lever delivered a 4-pellet reward after a fixed ratio of presses (2, 5, 10, or 20) that increased over 4 blocks of 10 discrete choice trials. Subsequent testing employed an equivalent delays procedure, whereby the relative delay to reward delivery after selection of either option was equalized. In well-trained rats, inactivation of the core, but not the shell, via infusion of GABA A/B agonists muscimol/baclofen reduced preference for the high-effort option under standard conditions and also when rats were tested using an equivalent delays procedure. However, inactivation of the core did not alter preference for 4-pellet versus 2-pellet rewards when the relative costs of each option were the same (1 press). Thus, the NAc core, but not the shell, appears to be part of a neural circuit that biases choice toward larger rewards associated with a greater effort cost. Furthermore, the contributions by the NAc core to this form of decision making can be dissociated from its role in delay discounting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impulsivity and rapid discounting of delayed hypothetical rewards in cocaine-dependent individuals.

In this study, crack/cocaine-dependent (CD) and non-drug-using matched control (MC) participants were presented with hypothetical immediate and delayed rewards, with 16 delay conditions ranging from 5 min to 25 years. All participants were presented with hypothetical monetary rewards; however, the CD group was also presented with hypothetical crack/ cocaine rewards. The objective value of the rewards ranged from $1 to $1,000. Hyperbolic discounting functions provided a good fit of the data. The CD group discounted monetary rewards at a higher rate than the MC group did, and the CD group discounted crack/cocaine rewards at a higher rate than it did monetary rewards. Moreover, scores on self-report measures indicated greater impulsivity in the CD group when compared with the MC group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal Discounting When the Choice Is Between Two Delayed Rewards.

The present experiments extend the temporal discounting paradigm from choice between an immediate and a delayed reward to choice between 2 delayed rewards: a smaller amount of money available sooner and a larger amount available later. Across different amounts and delays, the data were consistently well described by a hyperbola-like discounting function, and the degree of discounting decreased systematically as the delay to the sooner reward increased. Three theoretical models (the elimination-by-aspects, present-value comparison, and common-aspect attenuation hypotheses) were evaluated. The best account of the data was provided by the common-aspect attenuation hypothesis, according to which the common aspect of the choice alternatives (i.e., the time until the sooner reward is available) receives less weight in the decision-making process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solving the Neoclassical Growth Model with Quasi-Geometric Discounting: A Grid-Based Euler-Equation Method

The standard neoclassical growth model with quasi-geometric discounting is shown elsewhere (Krusell, P. and Smith, A., CEPR Discussion Paper No. 2651, 2000) to have multiple solutions. As a result, value-iterative methods fail to converge. The set of equilibria is however reduced if we restrict our attention to the interior (satisfying the Euler equation) solution. We study the performance of a grid-based Euler-equation methods in the given context. We find that such a method converges to an interior solution in a wide range of parameter values, not only in the “test” model with the closed-form solution but also in more general settings, including those with uncertainty. JEL Classification: C73, D90, E21     

基于服务质量和恶意结点消除的云计算环境信任模型分析

云计算环境下如何为应用程序选择可靠的服务是一个关键问题。论文借鉴人类社会建立推荐信任模型的方法,考虑云计算服务结点之间推荐信息的不确定性,提出基于服务提供的QoS属性为参考元素建立基本可信度函数,将历史交互信息转化为结点之间的推荐偏好意见,并采用衰减算子和融合算子综合不同云计算结点的推荐信息;针对推荐结点中的恶意结点,采用基于三角模糊数的方法对推荐结点进行分类,并采用不同的衰减算子计算每个推荐结点的推荐信任空间。分析和仿真实验证明该模型的有效性。     

Dimensions of impulsive behavior in adolescents: Laboratory behavioral assessments.

Impulsivity is a multifaceted construct that defines a range of maladaptive behavioral styles. The present research aimed to identify different dimensions of impulsive behavior in adolescents from a battery of laboratory behavioral assessments. In one analysis, correlations were examined between two self report and seven laboratory behavioral measures of impulsivity. The correlation between the two self report measures was high compared to correlations between the self report and laboratory behavioral measures. In a second analysis, a principal components analysis was performed with just the laboratory behavioral measures. Three behavioral dimensions were identified--"impulsive decision-making", "impulsive inattention", and "impulsive disinhibition". These dimensions were further evaluated using the same sample with a confirmatory factor analysis, which did support the hypothesis that these are significant and independent dimensions of impulsivity. This research indicates there are at least three separate subtypes of impulsive behavior when using laboratory behavioral assessments with adolescent participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)