采用3电平非均匀量化的脉冲编码策略

作为全数字发信机系统中广泛应用的一种脉冲编码技术,Delta-Sigma调制(Delta-Sigma Modulation, DSM)通过增加量化电平,能够实现调制性能的提升。但限于全数字发信机系统开关功放的具体结构,多电平DSM序列无法直接驱动后级功放电路。在传统3电平DSM基础上,通过引入面积等效原理和非均匀量化技术,提出了适用于开关功放的一种新的脉冲编码策略。理论分析和仿真结果表明,相比常规2电平DSM序列,采用该策略获得的调制脉冲序列具有更优的带内SNR和编码效率性能。     

MABAC method for multiple attribute group decision making under q-rung orthopair fuzzy environment

As the generalization of intuitionistic fuzzy set (IFS) and Pythagorean fuzzy set (PFS), the q-rung orthopair fuzzy set (q-ROFS) has emerged as a more meaningful and effective tool to solve multiple attribute group decision making (MAGDM) problems in management and scientific domains. The MABAC (multi-attributive border approximation area comparison) model, which handles the complex and uncertain decision making issues by computing the distance between each alternative and the bored approximation area (BAA), has been investigated by an increasing number of researchers more recent years. In our article, consider the conventional MABAC model and some fundamental theories of q-rung orthopair fuzzy set (q-ROFS), we shall introduce the q-rung orthopair fuzzy MABAC model to solve MADM problems. at first, we briefly review some basic theories related to q-ROFS and conventional MABAC model. Furthermore, the q-rung orthopair fuzzy MABAC model is built and the decision making steps are described. In the end, An actual MADM application has been given to testify this new model and some comparisons between this novel MABAC model and two q-ROFNs aggregation operators are provided to further demonstrate the merits of the q-rung orthopair fuzzy MABAC model.     

It Takes Two to Tango: Autocratic underbalancing,regime legitimacy and China’s responses to India’s rise

What factors do autocracies evaluate when responding to perceived threats and why might they fail to balance appropriately? I posit that autocratic leaders may choose greater exposure to an external threat if, by doing so, it preserves regime legitimacy. Specifically, the desire to promote a positive image to one’s domestic public creates incentives to publicly downplay a rival’s military progress, which then affects the state’s ability to mobilize resources to respond to the growing threat. I test this theory in the case of China’s response to India’s military rise. This research contributes to balancing theory and empirical work on East Asian security.     

Nash bargaining over allocations in inventory pooling contracts

When facing uncertain demand, several firms may consider pooling their inventories leading to the emergence of two key contractual issues. How much should each produce or purchase for inventory purposes? How should inventory be allocated when shortages occur to some of the firms? Previously, if the allocations issue was considered, it was undertaken through evaluation of the consequences of an arbitrary priority scheme. We consider both these issues within a Nash bargaining solution (NBS) cooperative framework. The firms may not be risk neutral, hence a nontransferable utility bargaining game is defined. Thus the physical pooling mechanism itself must benefit the firms, even without any monetary transfers. The firms may be asymmetric in the sense of having different unit production costs and unit revenues. Our assumption with respect to shortage allocation is that a firm not suffering from a shortfall, will not be affected by any of the other firms' shortages. For two risk neutral firms, the NBS is shown to award priority on all inventory produced to the firm with higher ratio of unit revenue to unit production cost. Nevertheless, the arrangement is also beneficial for the other firm contributing to the total production. We provide examples of Uniform and Bernoulli demand distributions, for which the problem can be solved analytically. For firms with constant absolute risk aversion, the agreement may not award priority to any firm. Analytically solvable examples allow additional insights, e.g. that higher risk aversion can, for some problem parameters, cause an increase in the sum of quantities produced, which is not the case in a single newsvendor setting. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

Noncooperative cost spanning tree games with budget restrictions

We extend the noncooperative game associated with the cost spanning tree problem introduced by Bergantiños and Lorenzo (Math Method Oper Res 59(2004), 393–403) to situations where agents have budget restrictions. We study the Nash equilibria, subgame perfect Nash equilibria, and strong Nash equilibria of this game. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008     

基于证据熵对不确定性度量的决策表约简

知识约简是粗糙集理论的核心内容之一,产生的粗糙决策规则往往具有一定的不确定性.在变精度粗糙集的基础上,本文构造了符合证据理论框架的一组焦元,利用基本概率分配函数计算了证据的总体信息熵,度量了决策表的不确定性;以该度量作为启发信息,给出了决策表的启发式知识约简算法.计算实例表明了本文方法的有效性.     

Hybrid warfare through the lens of strategic theory

Hybrid warfare is the latest of the terms/concepts that have been used within the defence community in the last three decades to label contemporary warfare. It has been officially adopted in the core strategic documents of NATO, EU and national governments and has already inspired many articles, policy papers and books; however, this paper is unique in the sense that it analysis the hybrid warfare concept through the lens of strategic theory. It is argued that hybrid warfare does not merit the adoption as a doctrinal concept. Strategic theory instead, which lies at the nexus of all dimensions of warfare, provides a better viewpoint to approach contemporary warfare. It concludes that efforts should be directed towards exploring warfare under the light of eternal principles instead of proving the emergence of new types of warfare.     

燃气发生器低频非稳态燃烧统计分析

针对冲压发动机地面试验需求,设计燃气发生器,通过试验统计研究其燃烧稳定性特征。结果表明:该燃气发生器发生低频非稳态燃烧的概率为32.7%,存在两种振荡形态。一种存在振荡主频,即低频不稳定燃烧;另一种没有主频,燃烧形态为粗暴燃烧。粗暴燃烧发生概率高且与余氧系数存在较强的相关性,低频不稳定燃烧发生概率低。两种形态的振荡能量分布位置不同。     

基于纯方位理论的运动舰船长度测量方法

获得运动舰船的船体长度对于航海避碰和目标识别具有重要的参考价值。然而,由于诸多因素的限制,现有视觉技术难以精确测量。为此,引入了纯方位目标运动分析理论结合双目视觉技术实现对运动舰船长度的测量。首先就所研究问题建立运动模型,推导了基于目标舰船方位、距离参数的舰船长度测量方法,针对该方法测量误差大的问题提出了基于航向、距离、方位的舰船长度测量方法。目标航向无法直接获取,为此引入基于纯方位理论的目标航向视觉估计方法,并进行了仿真验证。最后对两种舰船长度测量模型的误差进行了仿真比较分析,结果表明采用本文提出的"距离航向"法,当观测点位于目标舰船正横左右范围内时误差可以控制在10%内,"方位距离"法误差更小,适用的舷角范围更大。     

一种基于证据间距离和信息熵的证据组合方法?

针对改进的基于证据间距离的组合方法,首先计算证据间距离并求出各个证据的支持度和可信度,选取支持度高的作为较可信证据,其次引入证据信息熵,计算修正系数,对这些证据的可信度进行修正,将可信度作为权重,进行证据的加权平均,再利用Dempster组合规则对所有证据进行融合。算例表明,该方法比现有的方法更加有效。