机载鱼雷攻潜方式选择研究

为选择合理的机载鱼雷攻潜方式,依据直升机悬停攻击,建立了鱼雷投放参数解算模型;依据前飞攻击,分析了投雷圆半径,建立了投雷参数解算模型。提出常规法和排除法2种选择方式,仿真不同阵位下2种攻击方式的命中概率。仿真结果表明,与悬停攻击相比,前飞攻击时目标散布区相对缩小,鱼雷命中概率较高;直升机处于敌小舷角时有利提前角较小,避免了鱼雷与潜艇的尾追态势,鱼雷命中概率较高,建议优先采用前飞小舷角攻击方式。实际作战中,还应依据战场态势合理选择攻潜方式。结论对直升机反潜作战使用具有一定指导意义。     

基于复杂网络的集装箱海运系统的鲁棒性研究

基于复杂网络理论,定义集装箱海运网络的稳定鲁棒性和性能鲁棒性,通过数值模拟,计算网络的度分布、簇系数、平均路径长度等指标,并研究集装箱海运网络在随机和蓄意两种攻击方式下的鲁棒性表现。研究结果表明,集装箱海运网络虽体现一些无标度特性,但仍以随机性为主;鲁棒性较好,且遵循一定的变化规律。本研究为集装箱海运系统能够稳定持续运行提供理论依据,也对提高网络的抗干扰能力、增强其鲁棒性提出研究思路。     

An identity-based encryption scheme with compact ciphertexts

This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user's public key. The advantage of an identity-based public key system is that it can avoid public key certificates and certificate management. Our identity-based encryption scheme enjoys short ciphertexts and provable security against chosen-ciphertext attack (CCA).     

Distributed certificateless key encapsulation mechanism secure against the adaptive adversary

This paper proposes an adaptively secure solution to certificateless distributed key encapsulation mechanism from pairings by using Canetti's adaptive secure key generation scheme based on discrete logarithm. The proposed scheme can withstand adaptive attackers that can choose players for corruption at any time during the run of the protocol, and this kind of attack is powerful and realistic. In contrast, all previously presented threshold certificateless public key cryptosystems are proven secure against the more idealized static adversaries only. They choose and fix the subset of target players before running the protocol. We also prove security of this scheme in the random oracle model.     

Influence of Angle of Attack and Lateral Force between Wheel and Rail on Wear of Rail--a Laboratory Study

Angle of attack and lateral force are two important parameters influencing wheel-rail wear. This paper deals with the question of influences of the angle of attack and the lateral force on the wear of rail. A series of experiments are conducted on 1/4 JD-1 Wheel/Rail Tribology Simulation Facility. The angles of attack selected in the tests are 0°16′30″, 0°37′40″ and 1°0′0″ respectively. The lateral forces selected in the tests are 0.694 kN, 1.250 kN and 2.083 kN, respectively corresponding to the lateral forces of 25 kN, 45 kN and 75 kN measured in the field, with the aim of keeping the same ratio of L/V between laboratory and field conditions. It is found that the larger the angle of attack is, the more serious the wear of rail is. The relation of rail wear rate versus angle of attack is non-linear, and the relation of rail wear rate versus lateral force is approximately linear. The influence of angle of attack is more serious than that of lateral force. For the tractive wheelset, the wear index involving linear and quadratic function terms of angle of attack has good agreement with the limited experimental data. Some conclusions are given.     

恐怖袭击情境下地铁车站应急疏散仿真方法改进研究

在梳理分析国内外研究文献与实践状况的基础上,针对恐怖袭击情境下地铁车站的乘客应急疏散仿真,首先建议基于疏散心理和行为特征对乘客群体进行科学分类并差异化地赋予不同类型乘客相应的行为仿真参数,以提高仿真结果的可靠性;其次,在简要分析恐怖袭击情境下地铁车站乘客应急疏散心理与行为响应过程的基础上,重点通过情境问卷调查研究了特定恐怖袭击情境下乘客的典型应急疏散选择行为,并根据乘客不同的应急疏散行为反应模式对乘客群体进行了科学分类;然后,在分析给出乘客应急疏散心理与行为相关主要影响因素的基础上,通过多项logit模型分析,标明了乘客分类的显著影响因素,并利用本次情境问卷调查结果数据和上海市人口普查相关数据,估算了特定恐怖袭击情境下上海地铁车站乘客群体分类比例;最后,运用Massmotion人群疏散仿真软件,基于乘客的科学分类,对照进行了相应的实例疏散仿真,仿真结果的比较分析表明,对乘客群体进行科学分类并对不同类型乘客赋予相应的行为仿真参数会对应急疏散仿真结果产生显著影响。     

抗蚀系数法评价胶凝材料抗硫酸盐侵蚀性能试验研究

通过测试以不同胶凝材料配制的胶砂试件在硫酸盐侵蚀试验条件下的抗蚀系数,对胶凝材料的抗硫酸盐侵蚀性能进行研究和评价。研究结果表明：以90d作为抗蚀系数法评价胶凝材料抗硫酸盐侵蚀性能的侵蚀龄期较为合适,提出了抗蚀系数法评价胶凝材料抗硫酸盐侵蚀性能的方法,将胶凝材料的抗硫酸盐侵蚀能力由弱到强依次划分为“极低”、“低”、“中”、“高”和“极高”5个等级;硅酸盐水泥的抗硫酸盐侵蚀性能优于普通硅酸盐水泥,但两者的抗硫酸盐侵蚀能力均很低;矿物掺合料并不总能改善胶凝材料的抗硫酸盐侵蚀能力,但选择合理的掺量,单掺或复掺矿物掺合料均可大幅度提高胶凝材料的抗硫酸盐侵蚀性能。分析了不同种类胶凝材料的抗硫酸盐侵蚀机理。     

基于最优化理论的机步师联合火力打击目标价值评估

根据信息化条件下机步师城市进攻战斗联合火力打击特点,以最优化理论为基础,对战场联合火力打击目标价值进行了分析和排序,并通过实例对该模型的有效性和实用性进行了验证,为指挥员的决策行为提供了理论依据。     

舰船船底破损后的外载荷和应力研究

以某舰船为例,用符拉索夫法计算了鱼雷在舰船底部非接触爆炸使舰体结构产生破损后由于进水引起的浮态和载荷变化,给出了鱼雷命中破损后波浪弯矩随不同破损部位、不同进水体积的变化规律。在此基础上计算了鱼雷爆炸使舰体结构产生破损后的应力。研究指出,计算破损舰船结构应力时必须同时考虑破损使结构承载力大大下降和由于进水引起的浮态和载荷变化对舰艇生命力的影响。舰体结构的正应力和剪应力都随着进水体积的增大而增大,鱼雷最危险的命中位置是船中和剪力最大处。研究对舰船生命力的评估有重要意义。     

应力和干湿循环共同作用下硫酸根在混凝土中传输试验研究

对混凝土试件施加应力后，按一定周期将其在硫酸钠溶液中浸泡，再风干形成干湿循环作用。采用钻芯、分层切片、研磨提取水泥石粉末样本进行化学分析，测定不同深度处混凝土的硫酸根离子含量；研究在于湿循环作用下，混凝土受到的拉应力、压应力对硫酸根离子在混凝土内传输的影响规律。结果表明：拉应力对硫酸根离子由外部侵蚀溶液向混凝土内的传输具有加速效果，且随拉应力水平的增加而增大；压应力对硫酸根离子在混凝土内的传输具有一定的抑制作用，但与压应力水平没有确切的相关性。