改革开放以来党对军队绝对领导的理论与实践

坚持党对军队的绝对领导是人民军队建军治军的根本原则和根本制度.伴随改革开放伟大历史进程的不断推进,党的历代领导集体毫不动摇地坚持党对军队的绝对领导,并在各个历史时期的国防和军队建设中丰富发展了这一根本原则的理论与实践.改革开放初期,党对军队绝对领导原则在拨乱反正中得以强调和坚持;改革深化时期,党对军队绝对领导原则在继承发扬中得以丰富和发展;新世纪新阶段,党对军队绝对领导原则在开拓创新中得以巩固和完善.     

谈奥巴马时代美国的联合国政策

奥巴马对联合国政策的调整，反映出奥巴马政府全球外交和安全战略的需要，体现了实用主义外交风格。较之于其前任，奥巴马将更加重视联合国维和行动，并让联合国更多地参与解决包括伊拉克和阿富汗在内的热点问题。奥巴马的联合国政策面临挑战，联合国仅仅是奥巴马实现美国国家利益的手段之一。     

宋代商标及其使用研究

宋代商业分工细致，竞争激烈，商人为了招揽顾客，推销自家商品，开始用“新颖”、“文雅”的名称命名自家商品，逐渐形成文字、图形或实物等不同类别的商品标识。宋代商标的使用，既维护了生产者和经营者的利益，也有利于商业经济的正常秩序；既提高了商品的信誉，保证了商品的质量，又扩大了商品服务的范围，增加了商品在市场中的竞争力。     

Balancing a one‐way corridor capacity and safety‐oriented reliability: A stochastic optimization approach for metro train timetabling

In urban rail transit systems of large cities, the headway and following distance of successive trains have been compressed as much as possible to enhance the corridor capacity to satisfy extremely high passenger demand during peak hours. To prevent train collisions and ensure the safety of trains, a safe following distance of trains must be maintained. However, this requirement is subject to a series of complex factors, such as the uncertain train braking performance, train communication delay, and driver reaction time. In this paper, we propose a unified mathematical framework to analyze the safety‐oriented reliability of metro train timetables with different corridor capacities, that is, the train traffic density, and determine the most reliable train timetable for metro lines in an uncertain environment. By employing a space‐time network representation in the formulations, the reliability‐based train timetabling problem is formulated as a nonlinear stochastic programming model, in which we use 0‐1 variables to denote the time‐dependent velocity and position of all involved trains. Several reformulation techniques are developed to obtain an equivalent mixed integer programming model with quadratic constraints (MIQCP) that can be solved to optimality by some commercial solvers. To improve the computational efficiency of the MIQCP model, we develop a dual decomposition solution framework that decomposes the primal problem into several sets of subproblems by dualizing the coupling constraints across different samples. An exact dynamic programming combined with search space reduction strategies is also developed to solve the exact optimal solutions of these subproblems. Two sets of numerical experiments, which involve a relatively small‐scale case and a real‐world instance based on the operation data of the Beijing subway Changping Line are implemented to verify the effectiveness of the proposed approaches.