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Person-borne improvised explosive devices (PBIEDs) are often used in terrorist attacks in Western countries. This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people exposed to this hazard. An explosive field test with a typical PBIED composed of a plastic explosive charge and steel nut enhancements was performed to record initial fragment behaviour, including positions, velocity, and trajectory angles. These data were used to predict the full trajectory of PBIED fragments using a probabilistic analysis. In the probabilistic analyses a probability of fatality or serious injury was computed. Based on the results presented, many practical conclusions can be drawn, for instance, regarding safe evacuation distances if a person were exposed to a suspected PBIED.  相似文献   
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The F‐35 Joint Strike Fighter (JSF) programme is important for innovation in the Dutch economy and also contributes to other programmes in the aerospace industry (spin‐off) and other industries (spillover). On top of the expected value of US$9.2 billion in development and production, based on interviews with 10 companies and research institutes, an expected spin‐off of US$1.1 billion and an expected spillover of US$120 million will result. In addition, over 23,000 man‐years are associated with the activities in the development and production of the JSF. This study excludes the large and labour‐intensive Maintenance, Repair and Overhaul (MRO) activities. Further validation of data and an update of current results is planned for 2006.  相似文献   
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The original Olson and Zeckhauser model of alliance burden‐sharing was based on the following four assumptions: (1) alliance defence is a pure public good; (2) allied nations make their security contribution decisions without consulting the other allies; (3) alliances produce only a single public good; and (4) alliance defence is produced with equal degrees of efficiency in all alliance nations. But while the first of these assumptions has received a great deal of attention in the alliance literature, the remaining ones have received comparatively less attention, particularly in terms of empirical analyses. This paper synthesizes a varied literature developed around these four assumptions, both substantively and theoretically, and shows that when these assumptions are brought closer to real world approximations, hypotheses regarding the potential for security cooperation with less free‐riding result. This article also provides a simple test of Western alliance burden‐sharing in the areas of military spending, development resources spending, and research and development spending that supports the hypothesis positing more equitable burden‐sharing.  相似文献   
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Pastoralist groups in Eastern Africa are extremely vulnerable as a result of inter-community conflicts, the harsh terrain, and unfavourable climatic conditions. They have been neglected by successive regimes on matters of socio-economic development. At present pastoralist areas in Eastern Africa have the lowest literacy rates and insufficient health care facilities. This article interrogates the historical relationship between governments, humanitarian groups and pastoralists. It notes with great concern that pastoralists have been branded as hunger-stricken populations with insignificant economic potential that can be harnessed from their day-to-day livelihood. They are treated as sedentary populations who need a constant supply of relief food to keep going. In order to reverse these misconceptions, the article places emphasis on mitigating the threats of intra-community conflicts, diseases and natural disasters through investment in social schemes and infrastructure in order to open up the areas for service provision. Indeed, for a majority of the pastoralists, insecurity comes not so much from traditional security concerns, but from human insecurity concerns about their survival, preservation of their lifestyle and well-being in a day-to-day context.  相似文献   
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