Generating interior search directions for multiobjective linear programming

A new multiobjective linear programming (MOLP) algorithm is presented. The algorithm uses a variant of Karmarkar's interior-point algorithm known as the affine-scaling primal algorithm. Using this single-objective algorithm, interior search directions are generated and used to provide an approximation to the gradient of the (implicitly known) utility function. The approximation is guided by assessing locally relevant preference information for the various interior directions through interaction with a decision maker (DM). The resulting algorithm is an interactive approach that makes its progress towards the solution through the interior of the constraints polytope.     

Using Lexicographic Parametric Programming for Searching a Non-dominated Set in Multiple-Objective Linear Programming

In this paper we propose an approach which makes it possible to search non-dominated and only non-dominated solutions in multiple-objective linear programming. The approach is based on the use of a reference direction and lexicographic parametric programming. The requisite theory is developed in the paper. The use of the approach is illustrated with a numerical example.     

The danger of conflating level-specific effects of control variables when primary interest lies in level-2 effects

In the multilevel modelling literature, methodologists widely acknowledge that a level-1 variable can have distinct within-cluster and between-cluster effects, and that failing to disaggregate these can yield a slope estimate that is an uninterpretable, conflated blend of the two. Methodologists have stated, however, that including conflated slopes of level-1 variables in a model is not problematic if substantive interest lies only in effects of level-2 predictors. Researchers commonly follow this advice and use methods that do not disaggregate effects of level-1 control variables (e.g., grand mean centering) when examining effects of level-2 predictors. The primary purpose of this paper is to show that this is a dangerous practice. When level-specific effects of level-1 variables differ, failing to disaggregate them can severely bias estimation of level-2 predictor slopes. We show mathematically why this is the case and highlight factors that can exacerbate such bias. We corroborate these findings with simulations and present an empirical example, showing how such distortions can severely alter substantive conclusions. We ultimately recommend that simply including the cluster mean of the level-1 variable as a control will alleviate the problem.     

Longitudinal Development of Memory for Temporal Order in Early to Middle Childhood

Abstract

Existing studies examining the development of temporal order memory show that although young children perform above chance on some tasks assessing temporal order memory, there are significant age-related differences across childhood. Yet, the trajectory of children’s ability to retrieve temporal order remains unclear as existing conclusions are drawn from cross-sectional studies. The present study utilized an accelerated longitudinal design in order to characterize the developmental trajectory of temporal order memory in a sample of 200 healthy 4- to 8-year-old children. Specifically, two tasks commonly used in the literature were tested longitudinally: a primacy judgment task and an ordering task. Results revealed that, even after controlling for differences in IQ, linearly increasing trajectories characterized age-related change in performance for both tasks; however, change appeared greater for the temporal ordering task. Further, performance on the two tasks was positively related, suggesting shared underlying mechanisms. These findings provide a more thorough understanding of temporal order memory in early to middle childhood by characterizing the developmental trajectories of two commonly used tasks and have important implications for our understanding of children’s developing memory more broadly.     

时间信息加工与信息加工时间特性双视角下的重要时间参数及其证据

时间既是人类信息加工的对象, 也是(非时间)信息加工的制约因素。数十毫秒至数秒之间的时间加工与人类日常生活关联紧密, 譬如主观计时、演奏及言语等活动。根据以往文献分析可知, 在该时间区域内, 20~ 60 ms、1/3~1 s、2~3 s是研究者关注的重要时间参数, 但是支持这些参数的证据尚存分歧。首先从“时间信息加工”和“信息加工的时间特性”的视角介绍时间参数的基本观点及其提出背景, 然后基于“时间信息加工”视角从行为学研究、脑损伤研究、神经药理学研究, 脑电研究、脑成像研究、经颅磁刺激研究、经颅直流电刺激研究等领域介评了1/3~1 s和2~3 s分界区域的证据, 接着基于“信息加工的时间特性”视角从时序知觉阈限研究、感觉运动同步研究、主观节奏研究、言语行为研究、知觉逆转研究、返回抑制研究及失匹配负波研究等领域介评了20~60 ms和2~3 s时间窗口的证据。未来研究既要注意构建基于分界区域与时间窗口的更强解释力的理论假说, 也要厘清分界区域与时间窗口的联系与区别。     

跨期选择中的年龄差异及其机制

随着老龄化形势日益严峻, 老年人的跨期选择受到越来越多学者的关注。目前关于跨期选择的年老化研究尚存分歧:有研究发现老年人比年轻人更偏好未来获得更大收益; 也有研究发现老年人的选择偏好和年轻人一样, 甚至比年轻人更偏好近期收益。从时间表征和结果价值表征两个维度上的加工过程去分析其对老年人跨期选择的影响, 并进一步阐述认知、动机和情绪因素对两个维度加工过程的影响, 这对于理解当前老年人跨期选择领域研究的分歧有重要科学意义。     

时间任务需求对无关情绪面孔注意捕获的影响

注意捕获是指与任务无关的刺激能够不自觉地吸引注意的现象。实验一采用视觉搜索任务,考察与主任务无关的情绪面孔的注意捕获水平及其机制,实验二进一步探究时间任务需求对无关情绪面孔注意捕获的影响。结果发现:与其他情绪面孔相比,愤怒的情绪面孔捕获了更多的注意,且受到整体情绪加工的影响;时间任务需求影响了目标刺激的注意选择,但愤怒优势效应不受到时间任务需求的影响,因此可能是一种较为自动化的加工过程。     

逻辑训练对不同理性思维方式大学生三段论推理的影响

采用理性—经验思维方式量表对105名大学生进行测量,选出高、低理性思维方式各35名大学生进行实验,探讨了逻辑训练对不同理性思维方式大学生三段论推理的影响。结果表明：(1)高理性思维方式个体三段论推理的平均反应时快于低理性思维方式个体;非冲突类型题目推理的平均正确率高于冲突类型题目;逻辑训练可以提高个体三段论推理的平均反应时和正确率;(2)逻辑训练后非冲突任务类型题目的平均正确率高于冲突任务类型题目;(3)逻辑训练对低理性思维方式个体冲突任务类型题目平均正确率的提高效果更明显。这意味着逻辑训练可以显著提升个体的推理成绩,但不能完全消除信念偏差对推理的影响,而且逻辑训练对低理性思维方式个体推理成绩的提升效果更加明显。     

On normal theory based inference for multilevel models with distributional violations

Data in social and behavioral sciences are often hierarchically organized though seldom normal, yet normal theory based inference procedures are routinely used for analyzing multilevel models. Based on this observation, simple adjustments to normal theory based results are proposed to minimize the consequences of violating normality assumptions. For characterizing the distribution of parameter estimates, sandwich-type covariance matrices are derived. Standard errors based on these covariance matrices remain consistent under distributional violations. Implications of various covariance estimators are also discussed. For evaluating the quality of a multilevel model, a rescaled statistic is given for both the hierarchical linear model and the hierarchical structural equation model. The rescaled statistic, improving the likelihood ratio statistic by estimating one extra parameter, approaches the same mean as its reference distribution. A simulation study with a 2-level factor model implies that the rescaled statistic is preferable.This research was supported by grants DA01070 and DA00017 from the National Institute on Drug Abuse and a University of North Texas faculty research grant. We would like to thank the Associate Editor and two reviewers for suggestions that helped to improve the paper.     

On the Consistency of the Δ1 1-CA Fragment of Frege's Grundgesetze

It is well known that Frege's system in the Grundgesetze der Arithmetik is formally inconsistent. Frege's instantiation rule for the second-order universal quantifier makes his system, except for minor differences, full (i.e., with unrestricted comprehension) second-order logic, augmented by an abstraction operator that abides to Frege's basic law V. A few years ago, Richard Heck proved the consistency of the fragment of Frege's theory obtained by restricting the comprehension schema to predicative formulae. He further conjectured that the more encompassing ¹ ₁-comprehension schema would already be inconsistent. In the present paper, we show that this is not the case.