On‐line algorithms for minimizing makespan on batch processing machines

We consider problem of scheduling jobs on‐line on batch processing machines with dynamic job arrivals to minimize makespan. A batch machine can handle up to B jobs simultaneously. The jobs that are processed together from a batch, and all jobs in a batch start and complete at the same time. The processing time of a batch is given by the longest processing time of any job in the batch. Each job becomes available at its arrival time, which is unknown in advance, and its processing time becomes known upon its arrival. In the first part of this paper, we address the single batch processing machine scheduling problem. First we deal with two variants: the unbounded model where B is sufficiently large and the bounded model where jobs have two distinct arrival times. For both variants, we provide on‐line algorithms with worst‐case ratio (the inverse of the Golden ratio) and prove that these results are the best possible. Furthermore, we generalize our algorithms to the general case and show a worst‐case ratio of 2. We then consider the unbounded case for parallel batch processing machine scheduling. Lower bound are given, and two on‐line algorithms are presented. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 241–258, 2001     

片上多核处理器的非阻塞环设计与物理实现

针对少量强核构成的片上多核处理器,设计了一种非阻塞双向环结构。该结构包含5层3种不同类型的环链路层,分别用于传输命令、大量数据以及小量数据;采用源路由方式,设计专门的拥塞控制网络,防止报文的相互覆盖;路由器采用无缓冲无阻塞结构,单节拍通过环的每个跳步,以降低环的传输延迟并实现可预知的确定延迟传输。针对环的链路距离长、位宽大的挑战,通过实验选择了合理的中继器插入方法,并采用相邻导线交替插入反相器以及信号线反向交错排布等串扰优化方法,对环进行物理设计和长链路进行延时优化。最终实现结果表明,所设计的环达到了1 GHz的工作主频,并具备高达256 GByte/s的链路带宽,完全满足高性能数字信号处理的需求。     

Brinkmanship,not COIN,in Pakistan’s post-9/11 Internal War

Politics is critical to making sense of Pakistani successes and failures in dealing with non-state armed groups. This includes domestic political currents; regional political currents; and the global impetus of the post-9/11 era. How these currents overlap renders to any reading of insurgency in Pakistan real complexity. This article engages with this complexity rather than shirking from it. Its hypothesis is that while the insurgency bordering Afghanistan has been an epicentre of Pakistani military efforts to fight the Taliban, this theatre is in of itself insufficiently inclusive to grasp the nature of Pakistan’s security challenges and its consequent responses.     

Rendezvous search when marks are left at the starting points

Leaving marks at the starting points in a rendezvous search problem may provide the players with important information. Many of the standard rendezvous search problems are investigated under this new framework which we call markstart rendezvous search. Somewhat surprisingly, the relative difficulties of analysing problems in the two scenarios differ from problem to problem. Symmetric rendezvous on the line seems to be more tractable in the new setting whereas asymmetric rendezvous on the line when the initial distance is chosen by means of a convex distribution appears easier to analyse in the original setting. Results are also obtained for markstart rendezvous on complete graphs and on the line when the players' initial distance is given by an unknown probability distribution. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 722–731, 2001     

含缺陷管道评价标准及方法研究

为提高含缺陷管道剩余寿命预测的精确程度,系统阐述了国内外含缺陷管道的评价标准及评价方法,介绍了AGA NG-18标准、ASME B31G标准以及缺陷的具体评价方法,分析了各自的特点,针对评价方法提出了以有限元分析为研究方向的结论。     

Birth of a norm champion: how South Africa came to support the NPT’s indefinite extension

In 1995, South Africa was in a special position. It was: a new party to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), the first country to voluntarily renounce nuclear weapons, led by a charismatic leader, and seen as a champion of disarmament principles. Yet South Africa’s new leaders were also interested in affirming their position within the Non-Aligned Movement, which was adamantly opposed to the NPT’s indefinite extension. Why, then, did South Africa decide to support the indefinite extension of the NPT in 1995? Existing scholarship has ascribed too much credit to pressure from the United States, overlooking domestic debates in South Africa and the bifurcation between professional diplomats and political elites. This article, building on new archival sources and in-depth oral-history interviews with major actors, demonstrates that South African diplomats opposed indefinite extension while South African policy elites allocated little attention to the topic until late in the game. The findings contribute to our understanding of South Africa’s norm entrepreneurship, as well as the politics of global nonproliferation.     

Dynamic modeling and parameter identification of a gun saddle ring

In this study, a theoretical nonlinear dynamic model was established for a saddle ring based on a dynamic force analysis of the launching process and the structure according to contact-impact theory. The ADAMS software was used to build a parameterized dynamic model of the saddle ring. A parameter identification method for the ring was proposed based on the particle swarm optimization algorithm. A loading test was designed and performed several times at different elevation angles. The response histories of the saddle ring with different loads were then obtained. The parameters of the saddle ring dynamic model were identified from statistics generated at a 50° elevation angle to verify the feasibility and accuracy of the proposed method. The actual loading history of the ring at a 70° elevation angle was taken as the model input. The response histories of the ring under these working conditions were obtained through a simulation. The simulation results agreed with the actual response. Thus, the effectiveness and applicability of the proposed dynamic model were verified, and it provides an effective method for modeling saddle rings.     

微型导弹柔性充气翼结构设计与力学变形仿真

以NACA2412为基准翼型设计充气弹翼,采用柔性蒙皮应力分析理论并根据弹翼蒙皮材料强度极限理论建立考虑分布质量影响的改进应力表达模型,据此得到柔性薄膜弹翼允许充气压力范围。分析结果发现:柔性弹翼充气单元尺寸越小,相应的充气压力允许范围越大。采用ABAQUS/CAE软件以不可压缩壳单元仿真柔性充气弹翼在不同充气压力条件下的变形情况,发现非对称翼型充气后中间下凹的翘曲方式并确定柔性蒙皮的危险点,利用翼面典型线分析了充气翼局部力学变形特性。进一步对充气弹翼进行表面覆膜改进分析,获得了良好的结构力学性能改进效果。     

加工中心用触发式测头系统监测方法研究

主要研究了在数控加工中心ARROW500上使用触发式测头(英国Renishaw的MP12测头)实现零件加工的自动监测,通过深入研究用触发式测头在加工中心上实现在线监测的方法,使加工零件的序前调整、找正,序中监控及序后测量等可自动完成,实现了加工中心高效率、高自动化的监测。     

非接触爆炸作用下舰船动力系统生命力的研究方法

分析非接触爆炸作用下舰船动力系统中主要设备的破坏模式 ,建立了动力设备的冲击响应模式 ,并给出了在非接触爆炸作用下用于舰船动力系统生命力评估的系统破坏概率计算机仿真计算方法。