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This paper introduces and illustrates an approach to automatically detecting and selecting “critical” road segments, intended for application in circumstances of limited human or technical resources for traffic monitoring and management. The reported study makes novel contributions at three levels. At the specification level, it conceptualizes “critical segments” as road segments of spatially prolonged and high traffic accident risk. At the methodological level, it proposes a two-stage approach to traffic accident clustering and selection. The first stage is devoted to spatial clustering of traffic accidents. The second stage is devoted to selection of clusters that are dominant in terms of number of accidents. At the implementation level, the paper reports on a prototype system and illustrates its functionality using publicly available real-life data. The presented approach is psychologically inspired to the extent that it introduces a clustering criterion based on the Gestalt principle of proximity. Thus, the proposed algorithm is not density-based, as are most other state-of-the-art clustering algorithms applied in the context of traffic accident analysis, but still keeps their main advantages: it allows for clusters of arbitrary shapes, does not require an a priori given number of clusters, and excludes “noisy” observations.

Summary A new method for synchronous generator static excitation control is proposed in this paper, based on the PI controller and stabilizing feedback action. Compared with the existing solutions, this paper introduces improvements in the system's dynamic performance, robustness, and sensitivity in relation to noise, based on simplified control system structure modification. By introducing the stator voltage stabilizing feedback action, an improved level of dynamic performance is achieved, which also introduces an increased level of robustness. Furthermore, compared with sequential PID and lead–lag compensator based controllers proposed in related standards and technical papers, the system sensitivity in relation to the measurement noise is not compromised, since the differential control action is not included in the proposed controlling structure. The controller design procedure is performed by means of a frequency domain based technique, while its performance is verified by means of simulation and experimental test runs. Copyright © 2015 John Wiley & Sons, Ltd.