A branch-and-bound algorithm for fitting anti-robinson structures to symmetric dissimilarity matrices

The seriation of proximity matrices is an important problem in combinatorial data analysis and can be conducted using a variety of objective criteria. Some of the most popular criteria for evaluating an ordering of objects are based on (anti-) Robinson forms, which reflect the pattern of elements within each row and/or column of the reordered matrix when moving away from the main diagonal. This paper presents a branch-and-bound algorithm that can be used to seriate a symmetric dissimilarity matrix by identifying a reordering of rows and columns of the matrix optimizing an anti-Robinson criterion. Computational results are provided for several proximity matrices from the literature using four different anti-Robinson criteria. The results suggest that with respect to computational efficiency, the branch-and-bound algorithm is generally competitive with dynamic programming. Further, because it requires much less storage than dynamic programming, the branch-and-bound algorithm can provide guaranteed optimal solutions for matrices that are too large for dynamic programming implementations.     

Turing redux: Enculturation and computation

Many of our cognitive capacities are shaped by enculturation. Enculturation is the acquisition of cognitive practices such as symbol-based mathematical practices, reading, and writing during ontogeny. Enculturation is associated with significant changes to the organization and connectivity of the brain and to the functional profiles of embodied actions and motor programs. Furthermore, it relies on scaffolded cultural learning in the cognitive niche. The purpose of this paper is to explore the components of symbol-based mathematical practices. Phylogenetically, these practices are the result of concerted organism-niche interactions that have led from approximate number estimations to the emergence of discrete, symbol-based mathematical operations. Ontogenetically, symbol-based mathematical practices are associated with plastic changes to neural circuitry, action schemata, and motor programs. It will be suggested that these practices rely on previously acquired capacities such as subitizing and counting. With these considerations in place, I will argue that computations, understood in the sense of Turing (1936), are a specific kind of symbol-based mathematical practices that can be realized by human organisms, machines, or by hybrid organism-machine systems. In sum, this paper suggests a new way to think about mathematical cognition and computation.     

口碑追加形式对购买意向的影响:口碑方向的调节作用

网络购物越来越成为大众钟爱的购物方式,而网络口碑在网络购物中发挥着重要的作用,是消费者作出决策需要参考的重要因素。本研究以151名大学生为研究对象,通过实验操纵产品网络口碑,探讨不同追加形式(不追加、追加一致和追加不一致)和口碑方向(正向、负向)对购买意向的影响。结果表明:口碑方向调节追加形式对消费者购买意向的影响。正向口碑组中,不追加和追加一致组购买意向显著高于追加不一致组;负向口碑组中,不追加组,追加一致组和追加不一致组没有显著性差异。研究还发现了有中介的调节作用模型,满意度存在部分中介作用。本文最后对商家如何管理追加口碑进行了讨论。     

Approximations to the distribution of a test statistic in covariance structure analysis: A comprehensive study

In structural equation modelling (SEM), a robust adjustment to the test statistic or to its reference distribution is needed when its null distribution deviates from a χ² distribution, which usually arises when data do not follow a multivariate normal distribution. Unfortunately, existing studies on this issue typically focus on only a few methods and neglect the majority of alternative methods in statistics. Existing simulation studies typically consider only non-normal distributions of data that either satisfy asymptotic robustness or lead to an asymptotic scaled χ² distribution. In this work we conduct a comprehensive study that involves both typical methods in SEM and less well-known methods from the statistics literature. We also propose the use of several novel non-normal data distributions that are qualitatively different from the non-normal distributions widely used in existing studies. We found that several under-studied methods give the best performance under specific conditions, but the Satorra–Bentler method remains the most viable method for most situations.     

How our brains reason logically

The aim of this article is to strengthen links between cognitive brain research and formal logic. The work covers three fundamental sorts of logical inferences: reasoning in the propositional calculus, i.e. inferences with the conditional “if...then”, reasoning in the predicate calculus, i.e. inferences based on quantifiers such as “all”, “some”, “none”, and reasoning with n-place relations. Studies with brain-damaged patients and neuroimaging experiments indicate that such logical inferences are implemented in overlapping but different bilateral cortical networks, including parts of the fronto-temporal cortex, the posterior parietal cortex, and the visual cortices. I argue that these findings show that we do not use a single deterministic strategy for solving logical reasoning problems. This account resolves many disputes about how humans reason logically and why we sometimes deviate from the norms of formal logic.

Empirical evaluation of a model of global psychophysical judgments: IV. Forms for the weighting function

Understanding the psychological interpretation of numerals is of both practical and theoretical interest. In classical magnitude estimation, respondents match numerals to sensations and in magnitude production they select sensations that stand in a prescribed numerical ratio to a given standard. The present work focusses on evaluating several possible, and related, forms for the function W formulating the distortion of numerals. The main form, of which a power function is a special case, is the Prelec exponential/power representation. Behavioral equivalents to power and to Prelec functions are formulated, tested, and rejected. It is argued that either the mathematical form or the assumption W(1)=1 is wrong. Whereas, the axiomatic literature has focussed exclusively on the former inference, we explore the alternate that W(1)≠1. Behavioral axioms are formulated in each case and experimentally tested. We conclude that most respondents satisfy a general power function and that those who do not, satisfy the general Prelec function.     

The Internet as Cultural Form: Technology and the Human Condition in China

Raymond Williams’ work on television as a cultural form offers a theoretical basis for overcoming technological determinism in the study of the Internet. The Internet in China exerts social and political influences through the cultural forms it enables and then only when these forms respond to the human condition. Chinese Internet culture consists of new cultural forms that emerge out of the interactions between Internet and society and that are the products of both cultural tradition and innovation.

Good News for the Logical Autonomy of Ethics

Toomas Karmo claims that his taxonomy of ethical sentences has the result that there does not exist a sound argument with all non-ethical premises and an ethical conclusion. In a recent paper, Mark T. Nelson argues against this claim. Nelson presents a sound argument that he takes to be such that (i) Karmo’s taxonomy classifies that argument’s single premise as non-ethical and (ii) Karmo’s taxonomy classifies that argument’s conclusion as ethical. I attempt to show that Nelson is mistaken about (ii). For any possible world at which the premise of Nelson’s argument is true, Karmo’s taxonomy classifies the conclusion of Nelson’s argument as non-ethical.

小学汉语儿童英语口语产出形式的发展

以小学二、四、六年级共82名学生为研究被试, 通过自我介绍、被试主动发问、看图说话和角色扮演4种任务对其英语口语产出形式进行了测查。研究结果发现:(1)在小学汉语儿童英语口语产出形式上, 随着年级的升高, 套语的比例随之减少;其他语法错误句随年级升高而增多;正确的非套语也随年级升高而增多, 在四年级达到一个比较稳定的水平;(2)二年级儿童的英语口语产出形式以套语为主;四年级儿童的口语产出形式中正确非套语比例增加;在六年级儿童的口语产出中, 简化句比例增加, 但套语仍然是主要的一种口语产出形式。