A study of vibration and vibration control of ship structures

This paper examines the vibration characteristics and vibration control of complex ship structures. It is shown that input mobilities of a ship structure at engine supports, due to out-of-plane force or bending moment excitations, are governed by the flexural stiffness of the engine supports. The frequency averaged input mobilities of the ship structure, due to such excitations, can be represented by those of the corresponding infinite beam. The torsional moment input mobility at the engine support can be estimated from the torsional response of the engine bed section under direct excitation. It is found that the inclusion of ship hull and deck plates in the ship structure model has little effect on the frequency-averaged response of the ship structure. This study also shows that vibration propagation in complex ship structures at low frequencies can be attenuated by imposing irregularities to the ring frame locations in ships. Vibration responses of ship structures due to machinery excitations at higher frequencies can be controlled by structural modifications of the local supporting structures such as engine beds in ships.     

Are travelers substituting between transportation network companies (TNC) and public buses? A case study in Pittsburgh

Transportation - Transportation network companies (TNC) provide mobility services that are influencing travel behavior in unknown ways due to limited TNC trip-level data. How they interact with...     

Appraisal of rail investment projects: recent British experience

There has long been conflict over the degree to which railways should follow commercial or social investment criteria. This paper outlines the components of a comprehensive social cost‐benefit analysis of railway investment, and then describes the current approach in Britain. British Rail investment proposals are subject to a purely financial appraisal, although in the subsidized sectors of the railway this is subject to the proviso that a ‘broadly comparable’ level of service should be maintained. Local authorities and private operators are able to apply for a central government grant towards the cost of schemes they sponsor. But grant is only payable in respect of external benefits—that is, benefits other than to public transport users. Sponsors are also expected to seek contributions from private developers wherever possible. The difficulties to which this approach leads are discussed, and illustrated with two case studies of actual schemes. In one, it appears that failing to consider disbenefits to bus operators (and in turn to users of bus services) could lead to investments being undertaken which are not justified. In the other, a scheme which yields a high Net Present Value could not go ahead, in the form that we evaluated, because there is no way of recouping enough of the user benefits as revenue. Both are examples of the sort of distorting effect on decision‐making the current regime may have.     

Vehicle aesthetics and their impact on the pedestrian environment

Cars are designed to appeal to the buyer’s self-image, many of them evoking an impression of speed and power. Such an impression conflicts both with the aesthetic language of suburban architecture, and the needs of pedestrians. The research described in this report was conceived as a preliminary investigation of how members of the public view the aesthetic impact of cars in the residential street environment, particularly from the pedestrian’s point of view. The results suggested that people use two distinct sets of criteria when evaluating the motor car and the residential environment in visual terms. When asked to ‘match’ different models of car with different street scenes, respondents avoided referring to abstract visual qualities such as shape, colour and texture, but concentrated instead on the owners: the imagined driver and the imagined householder. The problem of visual harmony was reduced to one of social and cultural harmony. Could the imagined householder be expected to drive this or that car? However, SUVs were singled out as visually intrusive because they blocked the pedestrian’s view. Members of one of the groups, boys aged 11–12, found it difficult to visualise the impact of cars on pedestrians at all, or even to question vehicle design from the pedestrian’s point of view. They just wanted to be in the driving seat.     

雷诺-日产能否打破欧洲人不喜CVT的僵局?

2006年巴黎车展上,日产揭开了一款名为Qashqai的新车面纱.这是一款融合5门掀背运动车和四驱越野车的交叉车型,将在英国日产工厂生产.     

Are we there yet? Assessing smartphone apps as full-fledged tools for activity-travel surveys

Transportation - Given the limitations of traditional methods of data collection and the increased use of smartphones, there is growing attention given to using smartphone apps for activity-travel...     

A dual control approach for repeated anticipatory traffic control with estimation of network flow sensitivity

This paper investigates a strategic signal control, which anticipates travelers' route choice response and determines signal timings to optimize network‐wide objectives. In general traffic assignment models are used for anticipating this route choice response. However, model‐reality mismatch usually brings suboptimal solutions to the real system. A repeated anticipatory control resolves the suboptimality and addresses the modeling error by learning from information on model bias. This paper extends the repeated control approach and focuses on the estimation of flow sensitivity as well as its influence on control, which is a crucial issue in implementation of model bias correction. The main objective of this paper is first to analyze the estimation error in the real flow derivative that is estimated from noisy measurements. A dual control method is then presented, improving both optimization objective function and derivative estimation during the control process. The proposed dual algorithm is tested on a simple network as well as on a midsize network. Numerical examples confirm the reliable performance of the new reality‐tracking control strategy and its ability to identify (local) optimal solutions on real traffic networks. Copyright © 2016 John Wiley & Sons, Ltd.     

Noaa's civil penalty policy: Time for a change

Abstract

This article explores the lack of uniform penalty assessment in the National Oceanic and Atmospheric Administration's (NOAA) civil penalty policy under the Fishery Conservation and Management Act (the Magnuson Act). The author sugests that NOAA's inconsistent penalty assessment invites noncompliance by fishers because they view the penalties as unfair and arbitrary. In particular, deterrence is undermined by the absence of a provision that removes the economic benefits of noncompliance. NOAA's policy is contrasted with the Environmental Protection Agency's (EPA) civil penalty policy, which uniformly assesses penalties while tailoring the penalty to the individual facts of the case and effectively removing the economic incentives of noncompliance. If NOAA implemented a policy similar to EPA's, NOAA would secure increased Magnuson Act compliance and higher penalty amounts.     

r5.5 CHRONOGRAPH

源于内在。自然天成。双重天赋集于一身。纯粹恒久。低调简约。回归本真。瑞士制造整体陶瓷计时表限量版系列"少即是多(Less is More)",是雷达表著称的现代简约风格。这与世界殿堂级设计大师Jasper Morrison崇尚的"平常至极"理念一拍即合。     

European rail reform and passenger services - the next steps

Whilst the emphasis of European Union rail legislation to date has been on freight, measures such as separation of infrastructure from operations, infrastructure charging regimes and regulation have major implications for the passenger sector. But implementation of these measures in many countries has been inadequate. Crucial to overcoming these problems is the establishment of strong independent regulators in all member states. There is currently no requirement for competition in the passenger sector except for international services, but there is experience both of open access for commercial services and of competitive franchising. However, even where permitted open access competition has been very limited and there is evidence that undesirable cream skimming may be a problem. Experience of franchising has generally been positive, but in some cases it has failed to drive down costs. It is concluded that a combination of more sensible risk sharing, a determination not to renegotiate, longer franchises and limited open access competition where justified by benefits is likely to be the best way forward.