Risk based resilient network design

This paper presents a risk-based approach to resilient network design. The basic design problem considered is that given a working network and a fixed budget, how best to allocate the budget for deploying a survivability technique in different parts of the network based on managing the risk. The term risk measures two related quantities: the likelihood of failure or attack, and the amount of damage caused by the failure or attack. Various designs with different risk-based design objectives are considered, for example, minimizing the expected damage, minimizing the maximum damage, and minimizing a measure of the variability of damage that could occur in the network. A design methodology for the proposed risk-based survivable network design approach is presented within an optimization model framework. Numerical results and analysis illustrating the different risk based designs and the tradeoffs among the schemes are presented. © 2011 Springer Science+Business Media, LLC

A risk management approach to resilient network design

This paper considers the problem of where a survivability technique should be deployed in a network based on managing risk given a limited financial budget. We formulate three novel risk management resilient network design techniques: (1) minimize the maximum damage that could occur in the network, (2) minimize the maximum risk in the network and (3) minimize the root mean squared damage. The first two approaches try to minimize the damage/risk from the worst case failure scenario, where as the third technique minimizes the variability of damage across all failure scenarios. Numerical results for a sample network show the tradeoffs among the schemes. ©2010 IEEE

The use of non-standard motorcycle helmets in low- and middle-income countries: a multicentre study

Background The use of non-standard motorcycle helmets has the potential to undermine multinational efforts aimed at reducing the burden of road traffic injuries associated with motorcycle crashes. However, little is known about the prevalence or factors associated with their use. Methods Collaborating institutions in nine low- and middle-income countries undertook cross-sectional surveys, markets surveys, and reviewed legislation and enforcement practices around non-standard helmets. Findings 5563 helmet-wearing motorcyclists were observed; 54% of the helmets did not appear to have a marker/sticker indicating that the helmet met required standards and interviewers judged that 49% of the helmets were likely to be non-standard helmets. 5088 (91%) of the motorcyclists agreed to be interviewed; those who had spent less than US$10 on their helmet were found to be at the greatest risk of wearing a non-standard helmet. Data were collected across 126 different retail outlets; across all countries, regardless of outlet type, standard helmets were generally 2–3 times more expensive than non-standard helmets. While seven of the nine countries had legislation prohibiting the use of non-standard helmets, only four had legislation prohibiting their manufacture or sale and only three had legislation prohibiting their import. Enforcement of any legislation appeared to be minimal. Interpretation Our findings suggest that the widespread use of non-standard helmets in low- and middle-income countries may limit the potential gains of helmet use programmes. Strategies aimed at reducing the costs of standard helmets, combined with both legislation and enforcement, will be required to maximise the effects of existing campaigns