Measurement: a beginner's guide

This paper provides an introduction to measurement theory for psychometricians. The central concept in measurement theory is that of a continuous quantitative attribute and explaining what measurement is requires showing how this central concept leads on to those of ratio and real number and distinguishing measurements from measures. These distinctions made, the logic of quantification is described with particular emphasis upon the scientific task of quantification, as opposed to the instrumental task. The position presented is that measurement is the estimation of the magnitude of a quantitative attribute relative to a unit and that quantification is always contingent upon first attempting the scientific task of acquiring evidence that the relevant attribute is quantitative in structure. This position means that the definition of measurement usually given in psychology is incorrect and that psychologists' claims about being able to already measure psychological attributes must be seriously questioned. Just how the scientific task of investigating whether psychological attributes are quantitative may be undertaken in psychology is then considered and the corollary that psychological attributes may not actually be quantitative is raised.     

Determination of appropriate RF blocking impedance for MRI surface coils and arrays

Surface and phased array receiving coils in MRI typically require that RF excitation be accomplished using the body coil. This process requires that the receiving coils contain blocking circuitry to increase the overall circuit impedance during RF excitation and withstand the electromotive force induced by the applied electromagnetic field. The aim of this study was to determine the optimal impedance range required during RF excitation based on an assessment of image quality. The experimental results are fit by an exponential model and establish criteria that can be applied for general receiver coil design.     

Investigation of mixed convection in a large rectangular enclosure

This experimental research investigates mixed convection and heat transfer augmentation by gaseous forced jets in a large enclosure, at conditions simulating those of passive containment cooling systems for Gen III+ passively safe reactors. The experiment is designed to measure the key parameters governing heat transfer augmentation by forced jets, and to investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio. The tests cover a variety of injection modes leading to flow configurations of interest for mixing and stratification phenomena in containments under accident conditions. Correlations for heat transfer augmentation by forced jets are developed and compared with experimental data. The characteristic recirculation speed inside the enclosure is introduced and analyzed. Steady stratified temperature distributions are compared with model simulations of the BMIX++ code.     

Stability and variability of affective experience and interpersonal behavior in borderline personality disorder.

This study examined both mean levels and intraindividual variability in the mood and interpersonal behavior of individuals with borderline personality disorder (BPD) and nonclinical control participants over a 20-day event-contingent recording period. Individuals in the BPD group experienced more unpleasantly valenced affect and were less dominant, more submissive, more quarrelsome, and more extreme in overall levels of behavior than control participants. In addition to these mean-level differences, individuals with BPD also reported more intraindividual variability in overall affect valence and in pleasantly valenced affect; displayed greater variability in dominant, quarrelsome, and agreeable behaviors; and exhibited an increased tendency to "spin" among interpersonal behaviors relative to nonclinical control participants. The findings document behavioral and affective manifestations of BPD in the context of naturally occurring interpersonal situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in item manipulation span: The case of letter-number sequencing.

The authors report 2 experiments in which they examined age differences in working memory tasks involving complex item manipulation (i.e., letter-number sequencing). In Experiment 1, age differences on tasks involving item manipulation were not greater than age differences on tasks requiring recall of items in the order in which they appeared, suggesting that older adults do not have difficulty with item manipulation per se. In Experiment 2, slower presentation rates increased age differences in item manipulation spans, although age differences at the fastest rate may be attributed to differences in strategy use. In both experiments, age differences were largest when participants were most likely to be remembering familiar sequences, suggesting that older adults may have difficulties dampening the representations of such sequences once they are activated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nanoporous Gold Bowls: A Kinetic Approach to Control Open Shell Structures and Size‐Tunable Lattice Strain for Electrocatalytic Applications

Controlling sub‐10 nm ligament sizes and open‐shell structure in nanoporous gold (NPG) to achieve strained lattice is critical in enhancing catalytic activity, but it remains a challenge due to poor control of reaction kinetics in conventional dealloying approach. Herein, a ligament size‐controlled synthesis of open‐shell NPG bowls (NPGB) through hetero‐epitaxial growth of NPGB on AgCl is reported. The ligament size in NPGB is controlled from 6 to 46 nm by varying the hydroquinone to HAuCl₄ ratio. The Williamson–Hall analysis demonstrates a higher lattice strain in smaller ligament size. In particular, NPGB with 6 nm (NPGB 6) ligament size possess the highest strain of 15.4 × 10^?3, which is nearly twice of conventional 2D NPG sheets (≈8.8 × 10^?3). The presence of high surface energy facets in NPGBs is also envisaged. The best electrocatalytic activity toward methanol oxidation is observed in NPGB 6 (27.8 μA μg^?1), which is ≈9‐fold and 3‐fold higher than 8 nm solid Au nanoparticles, and conventional NPG sheets. The excellent catalytic activity in NPGB 6 is attributed to the open‐shell structure, lattice strain, and higher electro‐active surface area, allowing efficient exposure of catalytic active sites to facilitate the methanol oxidation. The results offer a potential strategy for designing next generation electrocatalysts.     

Examining Factors Influencing the Disruptiveness of Notifications in a Mobile Museum Context

Ubiquitous computing environments continuously infer our context and proactively offer us context aware services and information, suggested by notifications on our mobile devices. However, notifications come with a cost. They may interrupt the user in the current task and be annoying in the wrong context. The challenge becomes how to notify the user about the availability of relevant services while minimizing the level of disruptiveness. Thus, an understanding of what affects the subjective perception of the disruptiveness of the notification is needed. As yet, most of the research on disruptiveness of notifications focused on stationary, task-oriented environments. In this study, we examine the effect of notifications in a special leisure scenario—a museum visit. In two user studies conducted in a museum setting, participants used a context-aware mobile museum guide to receive information on various museum exhibits while periodically receiving notifications. We examined how the user’s activity, the modality of the notification, and the message content affected the perceived level of disruption that the notifications created. We discuss our results in light of existing work in the desktop and mobile domains and provide a framework and recommendations for designing notifications for a mobile museum guide system.     

An Observational Study of Dual Display Usage in University Classroom Lectures

We report a study of how dual display screens were used in classroom lectures for university-level courses across a variety of disciplines during five academic terms over a 2-year period. Our goal was to understand the pedagogical consequences of using more than a single electronic display screen to support classroom lectures. We deployed an in-house software system (MultiPresenter) in real classrooms. We examined the use of MultiPresenter by 8 university instructors who taught 15 courses with a total of 1,147 students during 13-week regular terms or 6-week summer terms. We observed classroom lectures, interviewed instructors, collected screen images and log files of MultiPresenter usage, and administered questionnaires to students about their subjective impressions. Based on these data, we analyzed how instructors used MultiPresenter in order to identify examples of how multiple display screens might best be used for educational purposes. The analysis revealed that the following practices are beneficial: the ability to keep information persistent for extended periods, the increased flexibility in where and when information is shown, capability for side-by-side comparison of full screens of information, simultaneous visibility of both overview (“roadmap”) and detailed (“content”) information, and extra space to annotate information. Possible hazards include difficulty focusing on specific information amidst a large amount of information and too much information changing too quickly without proper indication of the changes.     

减小电感尺寸,设计纤薄的PFC电源段

功率因数校正（PFC）电路嵌在交流线路与主电源之间，从交流线路汲入正弦电流，从而提供恒定直流电压。这中间段一般是升压转换器，电感是系统中体积最大且昂贵的元器件之一。在对成本和尺寸敏感的应用中，必须将电感的尺寸和成本降至最低。