Cognitive Fit: A Theory-Based Analysis of the Graphs Versus Tables Literature*

A considerable amount of research has been conducted over a long period of time into the effects of graphical and tabular representations on decision-making performance. To date, however, the literature appears to have arrived at few conclusions with regard to the performance of the two representations. This paper addresses these issues by presenting a theory, based on information processing theory, to explain under what circumstances one representation outperforms the other. The fundamental aspects of the theory are: (1) although graphical and tabular representations may contain the same information, they present that information in fundamentally different ways; graphical representations emphasize spatial information, while tables emphasize symbolic information; (2) tasks can be divided into two types, spatial and symbolic, based on the type of information that facilitates their solution; (3) performance on a task will be enhanced when there is a cognitive fit (match) between the information emphasized in the representation type and that required by the task type; that is, when graphs support spatial tasks and when tables support symbolic tasks; (4) the processes or strategies problem solvers use are the crucial elements of cognitive fit since they provide the link between representation and task; the processes identified here are perceptual and analytical; (5) so long as there is a complete fit of representation, processes, and task type, each representation will lead to both quicker and more accurate problem solving. The theory is validated by its success in explaining the results of published studies that examine the performance of graphical and tabular representations in decision making.     

DEVIL'S ADVOCACY AND DIALECTICAL INQUIRY EFFECTS ON PREDICTION PERFORMANCE: TASK INVOLVEMENT AS A MEDIATING VARIABLE

Critics of previous laboratory experiments comparing devil's advocacy (DA) to dialectical inquiry (DI) have suggested that these experiments produced misleading results because (1) they used subjects who had low levels of task involvement and (2) the DI treatment used was confusing to subjects and required further explanation to be useful. The present study examines the effects of four inquiry methods—expert (E), DA, DI, and DI with explanatory statement (DI+)—on subjects' performance at a financial prediction task. Results show that DA, DI, and DI + were superior to E when the state of the world differed significantly from assumptions underlying the expert's plan. For subjects with high task involvement, DI and DI + were more effective than E and DA. The results support some of the criticisms of previous laboratory research and suggest that future research on these decision aids should include task involvement as a factor.     

快速傅立叶变换在数字信号处理器上的实现研究

结合数字信号处理器的性能特点,对基2、基4、分裂基和Bruun FFT等快速傅立叶变换算法及其在TMS320C30上的实现进行了研究,开发出高效的FFT算法和程序。     

基于EMD的非线性信号自适应分析

根据EMD分解原理,提出通过选择平均包络中的突变点确定自适应滤波器截止分量阶,以此构造时空滤波器组进行非线性信号自适应分析的方法,成功应用于分析波音737飞机涡轮轴振动信号。从噪声中自适应地提取随转速变化的信号分量和低频振动分量,与小波分析方法相比,在轴向位移检测中取得了更为满意的效果。该方法不仅改进了涡轮轴振动信号分析方法,也适用于解决其他非线性信号的分析问题。     

基于虚拟仪器的检测技术创新实验教学平台

文章讨论了对原有的检测技术实验教学体系进行改革,构建了检测技术创新实验教学平台,给出了基于虚拟仪器技术的检测技术创新实验教学平台构建方案。     

近年来《关于正确处理人民内部矛盾的问题》的研究述评

《关于正确处理人民内部矛盾的问题》是毛泽东在社会主义建设时期最重要的理论著作之一.中共十一届三中全会以来对《关于正确处理人民内部矛盾的问题》的研究一直是学术界关注的热点问题,取得了丰硕成果.在其发表50周年之际,文章着重从近年来学术界对该文献研究的成果、研究的新视野、研究中带有争议的热点问题及研究中的不足等方面作一述评,以为纪念.     

C2C网上交易中信号机制的有效性分析

本文应用Berry等(1995)^[2]提出的离散选择需求模型和差异产品的伯川德竞争模型,并利用淘宝网上的交易数据,对声誉、消费者保障计划、保修服务及信息披露四种信号策略在网上交易中的作用进行了实证研究。需求估计结果表明消费者保障计划中的"7天无理由退换货"计划以及保修服务可以作为产品质量的信号;而在其他有效信号策略存在的情况下,消费者保障计划中的"先行赔付"计划以及卖家声誉作为质量信号的作用则被削弱。成本分析表明,信息披露虽然可以提高消费者购买的可能性,但是由于发出信号的成本太低,容易被低质量卖家所模仿,因此并不能作为有效的质量信号。本文首次从供给和需求两个方面分析了信号机制在信息不对称情况下的效应及其作用机制。     

Trend estimation of multivariate time series with controlled smoothness

This paper extends the univariate time series smoothing approach provided by penalized least squares to a multivariate setting, thus allowing for joint estimation of several time series trends. The theoretical results are valid for the general multivariate case, but particular emphasis is placed on the bivariate situation from an applied point of view. The proposal is based on a vector signal-plus-noise representation of the observed data that requires the first two sample moments and specifying only one smoothing constant. A measure of the amount of smoothness of an estimated trend is introduced so that an analyst can set in advance a desired percentage of smoothness to be achieved by the trend estimate. The required smoothing constant is determined by the chosen percentage of smoothness. Closed form expressions for the smoothed estimated vector and its variance-covariance matrix are derived from a straightforward application of generalized least squares, thus providing best linear unbiased estimates for the trends. A detailed algorithm applicable for estimating bivariate time series trends is also presented and justified. The theoretical results are supported by a simulation study and two real applications. One corresponds to Mexican and US macroeconomic data within the context of business cycle analysis, and the other one to environmental data pertaining to a monitored site in Scotland.     

The Peasant World in the Discourse of Generational Sorrow

This article spells out the methodological considerations and various procedural and methodological subtleties developed over the author's quarter century of sociological field studies of Russia's peasant worlds. Particular attention is paid to “voices from below”—peasant discursive formats that capture, in natural and undiluted form, the evolution of peasant practices constituting the core of everyday life. In particular, the phenomenon of generational sorrow and a special chronological nostalgia that functions as a “social gyroscope” is identified and discursively captured. This phenomenon is noteworthy and useful for its ability to retain a record of the productively longed for past in a rural community's collective memory and thereby influence new peasant worlds taking shape today.     

A direct procedure for monitoring the coefficient of variation using a variable sample size scheme

A variable sample size (VSS) scheme directly monitoring the coefficient of variation (CV), instead of monitoring the transformed statistics, is proposed. Optimal chart parameters are computed based on two criteria: (i) minimizing the out-of-control ARL (ARL₁) and (ii) minimizing the out-of-control ASS (ASS₁). Then the performances are compared between these two criteria. The advantages of the proposed chart over the VSS chart based on the transformed statistics in the existing literature are: the former (i) provides an easier alternative as no transformation is involved and (ii) requires less number of observations to detect a shift when ASS₁ is minimized.