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41.
This article introduces integro-differential equations as a new technique to study terrorism dynamics. An integro-differential equation is a mathematical expression that contains derivatives of the required function and its integral transforms. The technique is applied to two different dynamic models in terrorism: terrorism and tourism, and terrorist innovations. In the first model the number of tourists that appears in an integral term and also in a derivative term is impacted by the number of terrorists. In the second model the integro-differential equation for terrorist innovations relates them to terrorist attacks. The article shows how to solve, analyze, interpret, and deal with integro-differential equations. Integro-differential equations shed light on aspects of the models ignored when other techniques are used. This is particularly important for the evaluation of current counterterrorist policies, as well as to the formulation of new ones.  相似文献   
42.
ABSTRACT

In March 2015, the South Australian state government established a royal commission to investigate the financial, social, technical, diplomatic, and nonproliferation benefits and risks of expanding its nuclear industry, including activities related to uranium mining; enriching, reprocessing, and fabricating nuclear fuels for both domestic use and export; producing nuclear power; and storing radiological waste, including foreign spent reactor fuel. Given its enormous uranium reserves and current mining activities, some Australians have argued that Australia could benefit financially by expanding the mining sector and by adding value to its uranium exports by enriching the material and fabricating it into reactor fuel assemblies. Others have maintained that Australia can realize significant economic benefits by recycling and storing foreign spent fuel and producing carbon-free nuclear power. In the end, the commission recommended that Australia consider opening up a high-level waste repository to take in foreign spent fuel. It did not recommend any other nuclear activities at this time. The following viewpoint is based on testimony I delivered to the commission on the nuclear weapon proliferation implications of the proposed activities. If Australia wants to avoid the temptation of selling nuclear goods to states that might use these goods to make bombs, it should only consider new nuclear activities that can be entirely financed by the private sector and turn a profit without having to resort to foreign sales. This policy would also enable Australia to set an important, new international nonproliferation standard.  相似文献   
43.
石河子市作为新疆第三大城市,其体育产业的发展明显滞后。本文通过对石河子市体育产业现状的调查分析,阐述了该市体育产业发展的不足之处,旨在为石河子市体育产业向健康、可持续的方向发展提供参考。  相似文献   
44.
针对全国各地石化工业园区不断新建,化学灾害事故风险增大,以及灾害事故处置难度大的问题,以天津滨海新区石化工业园区为例,对石化工业园区灾害事故风险进行了全面分析,有针对性地提出了石化工业园区灾害事故处置的对策与建议。  相似文献   
45.
MDI一体化项目排污口对长江水质影响的预测   总被引:1,自引:0,他引:1  
以MDI一体化项目排污口为研究对象,采用二维水质数学模型,预测了不同水位条件下,MDI一体化项目各企业排放的废水污染物对长江下游水体水质的影响。预测结果表明,在达标排放前提下,除挥发酚、硝基苯外,各污染物对排污口下游长江水体水质影响较小,长江水体水质基本满足GB 3838—2002《地表水环境质量标准》中Ⅲ类标准要求;挥发酚、硝基苯在排污口下游会产生一定的超标污染带,岸边5 m以外,下游120 m以远即满足《地表水环境质量标准》中Ⅲ类标准要求,不会对下游水质安全造成影响。  相似文献   
46.
人员的优化配置对于提高装备制造效率具有重要意义。针对经典匈牙利算法不能解决具有并联环节的人员指派问题的不足,提出利用虚拟工作代替并联环节,将问题转化为典型的指派问题;通过判断虚拟工作的可实现性,迭代搜索得到最优解。以某多技能人员任务指派系统为例,详细介绍了该优化方法的步骤。优化结果很好地验证了改进算法的有效性。  相似文献   
47.
As the most knowledge-intensive industrial sectors, China’s defense industries are developing very fast. The present paper will explore the contribution of China’s defense innovation to its economic growth. Cobb–Douglas production function, integrating defense and non-defense stock in knowledge, is applied during the course. In addition, an input–output analysis of defense equipment procurement was done. Positive effect of China’s defense innovation on economic growth has been revealed by comparing the results from the two methods. And some suggestions are made to strengthen the effect.  相似文献   
48.
Controversy has long surrounded the role and profitability of US defense contractors. From a financial perspective the question becomes whether defense contractors earn greater profits and investor returns than other companies during military conflicts. We explore this question by examining the accounting profitability and investor returns of US aircraft manufacturers before, during, and after World War II and compare them to a sample of non-defense firms. We also examine the reactions of aircraft stock prices to important political and military events of the time. We find that (1) aircraft stocks exhibited positive abnormal returns around events associated with defense buildups and outbreaks of hostile action and negative returns around events signaling an end to hostilities, (2) the company’s accounting returns improved during the war but these higher accounting returns did not translate into higher stock returns for the shareholders, and (3) investors could have earned higher stock returns had they switched out of aircraft stocks after Pearl Harbor and reinvested the proceeds in the overall market.  相似文献   
49.
机床智能加工的体系结构   总被引:5,自引:0,他引:5       下载免费PDF全文
智能制造技术是近年来兴起的一种新型制造工程,是机械制造的发展方向。由于其研究尚处于起步阶段,其体系结构尚未形成,其精确内涵也正在发展之中。本文就智能制造中的一个重要组成部分──智能加工,探讨了单台机床智能加工的基本概念与基本研究内容,提出了机床智能加工系统的基本结构,论述了各组成模块的基本功能与作用。  相似文献   
50.
地震是引发石化企业火灾的重要潜在罪魁,且多造成惨重损失,鉴于罕见研究,本文着意对石化企业地震火灾的产生、特点及预防和初期火灾扑救对策作以探讨,以望减少该类火灾危害。  相似文献   
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