Most of touchable surfaces in MERS units were contaminated by patients and health care workers and the viable virus could shed through respiratory secretion from clinically fully recovered patients. These results emphasize the need for strict environmental surface hygiene practices, and sufficient isolation period based on laboratory results rather than solely on clinical symptoms.

Predispositions and orientation toward cooperation or competition with other jurisdictions can play a critical role in implementing regional collaboration. By examining collaboration at the micro level, this article investigates how individual factors, including perceptions of cooperation and competition, as well as institutional and environmental factors, are related to regional collaboration. In particular, the authors assert that competitive motivation may support the emergence of regional governance mechanisms. Th is article explores the relationships between competitive/cooperative motivations and interlocal collaboration networks based on a network survey conducted in the Orlando, Florida, metropolitan area. Th e authors apply a quadratic assignment procedure regression analysis to examine how dyadic conceptual ties of cooperation and competition, along with the eff ect of community characteristics, aff ect policy network structures for economic development. By comparing estimated coeffi cients with sampling distributions of coeffi cients from all of the permuted data sets, the regression results indicate the infl uences of perceived competition/cooperation on the network exchange.

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Magnetorheological (MR) dampers are one of the most promising control devices for civil engineering applications to earthquake hazard mitigation, because they have many advantages such as small power requirement, reliability, and low price to manufacture. To reduce the responses of the controlled structure by using MR dampers, a control system including a power supply, controller, and sensors is needed. However, when a lot of MR dampers are applied to large-scale civil structures, such as cable-stayed bridges and high-rise buildings, the control system becomes complex. Thus, it is not easy to install and to maintain the MR damper-based control system.In this paper, to resolve the above difficulties, a smart passive system is proposed, which is based on an MR damper system. The smart passive system consists of an MR damper and an electromagnetic induction (EMI) system that uses a permanent magnet and a coil. According to the Faraday law of induction, the EMI system that is attached to the MR damper produces electric energy. The produced energy is applied to the MR damper to vary the damping characteristics of the damper. Thus, the smart passive system does not require any power at all. Furthermore, the output of electric energy is proportional to input loads such as earthquakes, which means the smart passive system has adaptability by itself without any controller or corresponding sensors. Therefore, it is easy to build up and maintain the proposed smart passive system.To verify the effectiveness of the proposed smart passive system, the performance is compared with that of the normal MR damper-based control system. The numerical results show that the smart passive system has comparable performance to the normal MR damper-based control system.

SUMMARYA semi-active fuzzy control strategy for seismic response reduction using a magnetorheological (MR) damper is presented. When a control method based on fuzzy set theory for a structure with a MR damper is used for vibration reduction of a structure, it has an inherent robustness, and easiness to treat the uncertainties of input data from the ground motion and structural vibration sensors, and the ability to handle the non-linear behavior of the structure because there is no longer the need for an exact mathematical model of the structure. For a clipped-optimal control algorithm, the command voltage of a MR damper is set at either zero or the maximum level. However, a semi-active fuzzy control system has beneÿt to produce the required voltage to be input to the damper so that a desirable damper force can be produced and thus decrease the control force to reduce the structural response. Moreover, the proposed control strategy is fail-safe in that the bounded-input, bounded-output stability of the controlled structure is guaranteed. The results of the numerical simulations show that the proposed semi-active control system consisting of a fuzzy controller and a MR damper can be beneÿcial in reducing seismic responses of structures.

Spatio-temporal characteristics of wall pressure fluctuations in separated and reattaching flows over a backward-facing step were investigated through an extensive pressure-velocity joint measurement with an array of microphones. The experiment was performed in a wind tunnel with a Reynolds number of 33 000 based on the step height and the free-stream velocity. Synchronized wavelet maps showed the evolutionary behaviour of pressure fluctuations and gave further insight into the modulated nature of large-scale vortical structures. To see the relationship between the flow field and the relevant spatial mode of the pressure field, a new kind of wavenumber filtering, termed ‘spatial box filtering’ (SBF), was introduced and examined. The vortical flow field was reconstructed using every single-point velocity measurement by means of the conditional average based on the SBF second mode of pressure fluctuations. The flow field showed a well-organized spanwise vortical structure convected with a speed of 0.6U0 and a characteristic ‘sawtooth’ pattern of the unsteady trace of reattachment length. In addition to the coherent vortical structures, the periodic enlargement/shrinkage process of the recirculation region owing to apping motion was analysed. The recirculation region was found to undergo an enlargement/shrinkage cycle in accordance with the lowpass-filtered component of pressure fluctuations. In addition, such modulatory behaviour of the vortical structure as the global oscillation phase was discussed in connection with the conditionally averaged flow field.

This paper investigates the effectiveness of the MR damper‐based control systems for seismic protection of base‐isolated building structures employing some semi‐active control algorithms, such as the modified clipped‐optimal control, the maximum energy dissipation, the modulated homogeneous friction, and fuzzy logic‐based control algorithms, by examining the Phase I smart base‐isolated benchmark building problem. The results of the numerical simulations showed that most of the control systems considered herein could be beneficial in reducing seismic responses, especially the base displacement or the isolator deformation, of the base‐isolated building. If the base displacement is to be primarily reduced without regard to variation of the floor acceleration, the original clipped‐optimal control algorithm could be recommended. On the other hand, if it may be required to reduce the base displacement without increasing the floor acceleration, the modified clipped‐optimal control algorithm proposed in this study could be considered as one promising candidate for the linear benchmark base‐isolated system. Copyright © 2005 John Wiley & Sons, Ltd.

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