Are speed enforcement cameras more effective than other speed management measures? The impact of speed management schemes on 30mph roads.

This paper presents the results of an evaluation of the impact of various types of speed management schemes on both traffic speeds and accidents. The study controls for general trends in accidents, regression-to-mean effects and migration, separately estimating the accident changes attributable to the impact of the schemes on traffic speed and on traffic volume. It was found that, when judged in absolute terms, all types of speed management scheme have remarkably similar effects on accidents, with an average fall in personal injury accidents of about 1 accident/km/year. In terms of the percentage accident reduction, however, engineering schemes incorporating vertical deflections (such as speed humps or cushions) offer the largest benefits: at 44%, the average reduction in personal injury accidents attributable to such schemes, is twice that at sites where safety cameras were used to control speeds (22%) and they were the only type of scheme to have a significant impact on fatal and serious accidents. Other types of engineering scheme (with a fall of 29% in personal injury accidents) were on average less effective in reducing accidents than schemes with vertical features but more effective than cameras. All types of scheme were generally effective in reducing speeds, with the largest reductions tending to be obtained with vertical deflections and the smallest with other types of engineering schemes

Applying the proto-theory of design to explain and modify the parameter analysis method of conceptual design

This article reports on the outcomes of applying the notions provided by the reconstructed proto-theory of design, based on Aristotle’s remarks, to the parameter analysis (PA) method of conceptual design. Two research questions are addressed: (1) What further clarification and explanation to the approach of PA is provided by the proto-theory? (2) Which conclusions can be drawn from the study of an empirically derived design approach through the proto-theory regarding usefulness, validity and range of that theory? An overview of PA and an application example illustrate its present model and unique characteristics. Then, seven features of the proto-theory are explained and demonstrated through geometrical problem solving and analogies are drawn between these features and the corresponding ideas in modern design thinking. Historical and current uses of the terms analysis and synthesis in design are also outlined and contrasted, showing that caution should be exercised when applying them. Consequences regarding the design moves, process and strategy of PA allow proposing modifications to its model, while demonstrating how the ancient method of analysis can contribute to better understanding of contemporary design-theoretic issues

Influence Tactics Employed by High School Assistant Principals in Attempting to Influence their Principals

An important element of success in any managerial position rests in an ability to positively influence superiors. Nowhere in schooling is the need to be able to influence superiors more apparent than in the high school assistant principalship. Despite the similarity in titles, assistant principals are not principals. Their positions do not carry the authority of the principalship, and they-even more than a classroom teacher- are directly dependent upon the principal for job assignments, direction, permission, and support. Success in the assistant principalship requires a positive and mutually influential relationship with the principal. The nature of their work drives assistant principals to practice upward influence. The purpose of this survey study was to (a) identify influence practices employed by high school assistant principals; (b) to assess what impact, if any, gender may have upon tactic selection; (c) to assess what impact, if any, age has upon tactic selection; (d) to assess what impact, if any, the number of assistant principals in a building has upon tactic selection; (e) to assess what impact, if any, experience level has upon tactic selection. An assistant principal’s ability to successfully fulfill the responsibilities of his or her job is, at least in part, tied to the communication line to the principal. This study allows APs to know which upward influence tactics are available and utilized. Performance appraisals may well be tied to an AP’s ability to influence the principal. The perception of whether or not the AP has good communication skills may even be tied to persuasive prowess. This study provides additional knowledge regarding the high school assistant principalship and the work behaviors of those who hold the position. The findings may have implications for pre-service and in-service training for administrators

Method Effects and the Need for Cognition Scale

Individual differences in the need for cognition are typically assessed using the 18-item Need for cognition scale (NCS) developed by Cacioppo and Petty (1982). However, in contrast to the unidimensional model proposed by the scale developers, recent factor analyses have introduced two -and three- dimensional models of the scale. Confirmatory factor analyses were used in this study to evaluate different measurement models based on data provided by 590 (236 males, 354 females) young adult members of the general public. Although some alternative models showed promise, a single factor model with method effects associated with positively and negatively worded items provided best fit. Implications for the asses sment of need for cognition are considered

On the Experimental Estimation of Surface Enhanced Raman Scattering (SERS) Cross Sections by Vibrational Pumping

We present an in-depth analysis of the experimental estimation of cross sections in Surface Enhanced Raman Scattering (SERS) by vibrational pumping. The paper highlights the advantages and disadvantages of the technique, pinpoints the main aspects and limitations, and provides the underlying physical concepts to interpret the experimental results. Examples for several commonly used SERS probes are given, and a discussion on future possible developments is also presented.Comment: To be submitted to J. Phys. Chem.

Improved correction for the tissue fraction effect in lung PET/CT imaging

Recently, there has been an increased interest in imaging different pulmonary disorders using PET techniques. Previous work has shown, for static PET/CT, that air content in the lung influences reconstructed image values and that it is vital to correct for this 'tissue fraction effect' (TFE). In this paper, we extend this work to include the blood component and also investigate the TFE in dynamic imaging. CT imaging and PET kinetic modelling are used to determine fractional air and blood voxel volumes in six patients with idiopathic pulmonary fibrosis. These values are used to illustrate best and worst case scenarios when interpreting images without correcting for the TFE. In addition, the fractional volumes were used to determine correction factors for the SUV and the kinetic parameters. These were then applied to the patient images. The kinetic parameters K1 and Ki along with the static parameter SUV were all found to be affected by the TFE with both air and blood providing a significant contribution to the errors. Without corrections, errors range from 34-80% in the best case and 29-96% in the worst case. In the patient data, without correcting for the TFE, regions of high density (fibrosis) appeared to have a higher uptake than lower density (normal appearing tissue), however this was reversed after air and blood correction. The proposed correction methods are vital for quantitative and relative accuracy. Without these corrections, images may be misinterpreted

Closures and fairness in the semantics of programming logic

AbstractWe use the notions of closures and fair chaotic iterations to give a semantics to logic programs. The relationships between the semantics of individual rules and the semantics of the whole program are established and an application to parallel processing is mentioned. A chaotic fixed point theorem is given, which carries the non-determinism inherent to resolution. Finally, we introduce a general definition of finite failure and the concept of fair SLD resolution, and show that this procedure is sound and strongly complete with respect to both success and finite failure, thus extending a result of Apt and Van Emden (1982)