The fateful phoenix: the revival of Al-Qa’ida in Iraq

Although the Islamic State in Iraq and al-Sham (ISIS) is seen as a novel manifestation of Islamic extremism, it is in fact the latest, albeit perhaps the most effective, of a long line of revivalist movements in the Islamic and the Arab worlds. Its motivations – hisba and jihad – differ little from its predecessors and its ambitions – to create a state organised in accordance with the precepts of the Islamic caliphate – reflect a long-standing Islamic ambition. It differs, of course, in terms of the sophistication of its political and military strategies, which mirror the contemporary complexities of the world in which it operates, but its objectives recall long-standing Islamic ideals, even if articulated in radically brutal and extremist ways. More importantly, perhaps, ISIS or Da’ish, to give it its Arabic sobriquet, reflects the enormous degree of resentment inside the Middle East at the ways in which Western powers have intervened in regional affairs over recent years, particularly their support for regimes and economic systems there that have betrayed, in the popular imaginary, the essential principles of social justice that lie at the root of Islamic vision of ideal social order. Indeed, in many respects, its analysis of the world in which it operates and of the objectives it seeks differ little in essence from those any other resistance and rejectionist movement, whether religious or sectarian. More specifically, it has been the sectarian conflict that resulted from the reversal of political order in Iraq as a result of the 2003 American-led invasion that has driven the success of the movement in capturing widespread Sunni support. Whether it can manage the complexities of the administration of a state remains open to question.     

高精度有限体积格式在三维曲线坐标系下的应用

为了构造在光滑区具有较高分辨率并且可以无振荡捕捉激波的高精度有限体积格式,同时降低格式在模板选择上遇到的困难,基于逐维重构方法,发展了结构网格下的高精度有限体积格式,并将这一格式推广到三维曲线坐标系下,从而可以适应相对复杂外形下的计算。为充分验证格式的有效性,选取一系列典型算例进行计算:在等熵涡输运和二维喷管流动中验证了格式的精度可以达到设计精度;在双马赫反射问题中格式也表现出良好的捕捉激波的能力。数值计算表明,上述格式在曲线网格上具有较高的数值精度和鲁棒的激波捕捉能力,适用于流体力学方程的计算。     

E级超级计算机故障预测的数据采集方法

面向未来E级超级计算机,提出用于故障预测的数据采集框架,能够全面采集与计算结点故障相关的状态数据。采用自适应多层分组数据汇集方法,有效解决随着系统规模增长数据汇集过程开销过大的问题。在TH-1A超级计算机上的实现和测试表明,该数据采集框架具有开销小、扩展性好的优点,能够满足未来大规模系统故障预测数据采集的需求。     

Historical and Political Background to the Erosion of the Rule of Law and Human Rights During Sri Lanka’s Civil War and the Way Forward

The Sri Lankan Civil War (1983–2009) is regarded as a violent reflection of deepening divides along political and ethnic lines. During this civil war the Sri Lankan Government and its security forces have been implicated in unlawful killings carried out in a pervasive manner against civilians, whilst at the same time specifically targeting ethnic Tamils, humanitarian workers and journalists. The human rights of all citizens suffered as a result and ultimately led to the weakening of the rule of law. With the end of the civil war, the Sri Lankan Government has made little progress in providing accountability for wartime abuses. Its absence of and reluctance to ensure justice is seen as a logical culmination of decades of impunity. The importance of acknowledging historical behaviour and taking accountability for past violations will be discussed. In an analysis for paving the way to a new democracy in Sri Lanka, the main outcomes of this article are calls for accountability arising out of the government’s actions during the war; an investigation into the present state of human rights, the rule of law and finally; an examination into the political solution going forward to ensure a process of reconciliation and peaceful co-existence.     

动态滑翔运动建模、机理分析与航迹优化

信天翁凭借动态滑翔的飞行技巧从梯度风中获取能量,从而在几乎不拍翅膀的情况下进行长时间、长距离飞行,这种技巧应用于小型无人机上可拓展其完成任务的能力。基于飞行器动力学对梯度风场中的无人机运动方程进行推导和简化处理;利用简化的运动方程,分别从非惯性参考系中的动能定理和机械能变化的角度,对动态滑翔获取能量的机理进行分析;利用微分平坦法,以最小平均控制输入变化率为目标函数,对徘徊模式和平移模式的动态滑翔航迹进行优化计算。分析结果表明:逆风爬升、顺风下滑是动态滑翔基本获能方式。优化结果表明:控制输入变得更加平滑,甚至出现阶段性的常值,使得控制更加简化;徘徊模式下,当风梯度作为决策变量时,优化过程可在[0,0.5 s-1]的区间上找到使得目标函数值最小的风梯度;平移模式下,目标函数值在该区间上单调递减。     

考虑载荷作用次数的多失效模式扭力轴灵敏度分析

机械构件的不同的失效模式之间具有一定的相关性,而且随机载荷作用次数对机械构件的可靠性有一定程度的影响。因此对机械构件进行可靠性灵敏度分析时,需要充分考虑其不同失效模式和载荷作用次数的影响。通过运用顺序统计量理论考虑载荷多次作用以及多种失效模式条件下机械构件可靠性及可靠性灵敏度的变化规律,运用随机摄动理论和四阶矩技术,建立一种考虑载荷作用次数的多失效模式机械构件可靠性灵敏度分析数值方法的应力强度干涉模型。在随机变量前四阶矩已知的情况下,结合灵敏度分析的梯度算法,推导出关于随机变量均值和方差的灵敏度计算公式。以某履带车辆底盘扭力轴为例进行计算,得到其可靠度随载荷作用次数、随机变量均值和方差而改变的可靠性灵敏度变化曲线,为扭力轴的可靠性优化提供一定的理论依据。研究成果可以推广到相关机械可靠性灵敏度设计和结构优化领域,具有非常重要的实用意义。     

敷设气囊的充水圆柱壳的声辐射特性

为降低充水圆柱壳受内部点声源激励时的水下辐射噪声,在其外壳上敷设气囊,形成气囊圆柱壳。为指导气囊圆柱壳的设计,将充水裸圆柱壳和充水气囊圆柱壳分别简化为单、双层无限长隔板。比较隔板、气体与水的波阻抗,分析气体声速与层厚对双层无限长隔板在平面声波入射时的低频声辐射的影响机理。分析表明,声速小的气体和适当的气层厚度可以降低双层障板的辐射噪声。采用声无限元法计算气囊圆柱壳的水下声辐射,结论与对隔板的机理分析吻合。优化设计出的充水CO2气囊圆柱壳的水下辐射声功率与远场辐射声压明显低于充水裸圆柱壳。     

基于ADC方法的复杂武器系统效能评估方法

ADC方法是武器装备效能评估的重要方法之一。传统ADC方法一般将武器系统各个分系统简化为串联系统计算。针对复杂武器系统中各个分系统组成繁多、串并联关系复杂、对作战影响程度不一等特点,对ADC方法进行了优化,使得ADC方法可以针对多并联系统更客观地评估。通过某型武器装备的实际验证,改进后的ADC方法合理可行,可以对复杂武器系统拥有更客观和更全面地评价,可作为其他复杂武器系统效能评估方法的参考。     

武器装备体系能力矩阵评估方法

针对武器装备体系能力难以客观、定量评估的问题,引入复杂网络理论,提出了基于矩阵运算的武器装备体系能力评估方法。分析了武器装备体系能力的概念,建立了武器装备体系的复杂层次网络模型,描述了装备网络的组成、运行过程,定义了装备网络的矩阵描述方法和矩阵运算规则,提出了装备网络作战能力描述参数,给出了装备网络能力的矩阵计算方法,进行了影响因素分析,最后通过实例验证了方法可行性、有效性和灵活性。     

连续发射脉冲功率电源用水冷模拟负载研究

针对脉冲功率电源连续循环放电吸能需求,本文提出了一种1.9MA级循环脉冲功率水冷模拟负载方案。首先,考虑水冷负载与实际电磁发射负载的相似性要求,提出了4×8钢管阵列组成的电阻网络,可方便的实现电源不同组合方式的放电考核;其次,针对1.9MA级电流产生的脉冲电磁力可能引起水冷模拟负载损坏的问题,建立了水冷模拟负载三维有限元分析模型,进行了电磁力计算和结构分析,保证了水冷模拟负载稳定性;最后,利用热网络法对模拟负载在循环脉冲模式下的强迫风冷、自然冷却和去离子水冷却等方式进行了温升分析,结果表明：模拟负载采用钢管内通去离子水冷却效果最好,循环放电时温度可以恢复到初始状态,最高温度62.5℃,满足连续放电实验的需求。利用提出的方法设计了一台水冷模拟负载样机并进行了连续2次1.9MA放电研究,试验结果与理论分析吻合较好,负载结构运行稳定,验证了本文理论分析的正确性。