超奈奎斯特的频谱效率与参数优化分析

对超奈奎斯特(faster than Nyquist, FTN)和奈奎斯特系统的频谱效率进行了对比分析。在绝对带宽的前提下,首先证明了基于根升余弦函数脉冲的单载波FTN可达速率大于奈奎斯特可达速率,并推导了有子载波间干扰的多载波FTN的频谱效率公式。本文证明了单载波FTN的频谱效率大于奈奎斯特系统的频谱效率,并且证明了单载波FTN的频谱效率随着滚降因子的减小而增大。基于频谱效率公式和数值仿真,本文给出了多载波FTN对于不同滚降因子的最优子载波间隔。结果表明,即使存在子载波间干扰,基于最优子载波间隔的多载波FTN频谱效率也高于正交系统(奈奎斯特)的频谱效率。     

国防大数据概论

给出国防大数据的定义,归纳提炼国防大数据的特征,分析国防大数据所面临的挑战,并提出国防大数据研发和应用所需解决的科学问题及关键技术,最后给出发展建议。通过对国防大数据的研究,建立巨型国防大数据平台、货柜式国防大数据平台以及嵌入式国防大数据系统的概念,以便全面提升军队核心战斗力,在未来智能化战争中取得军事优势。     

A partial robust optimization approach to inventory management for the offline-to-online problem under different selling prices

This study examines an optimal inventory strategy when a retailer markets a product at different selling prices through a dual-channel supply chain, comprising an online channel and an offline channel. Using the operating pattern of the offline-to-online (O2O) business model, we develop a partial robust optimization (PRO) model. Then, we provide a closed-form solution when only the mean and standard deviation of the online channel demand distribution is known and the offline channel demand follows a uniform distribution (partial robust). Specifically, owing to the good structural properties of the solution, we obtain a heuristic ordering formula for the general distribution case (i.e., the offline channel demand follows a general distribution). In addition, a series of numerical experiments prove the rationality of our conjecture. Moreover, after comparing our solution with other possible policies, we conclude that the PRO approach improves the performance of incorporating the internet into an existing supply chain and, thus, is able to adjust the level of conservativeness of the solution. Finally, in a degenerated situation, we compare our PRO approach with a combination of information approach. The results show that the PRO approach has more “robust” performance. As a result, a reasonable trade-off between robustness and performance is achieved.     

A Class of Second-Order Consensus Protocol in Multi-Agent Systems with Multiple Input Delays

This paper is concerned with the consensus problems for second-order multi-agent systems with multiple input delays. Different from all standard consensus algorithms with uniform delays, the authors aim to find the largest input-delay margin which can guarantee the consensus for the case when delays are nonuniform. Based on frequency domain analysis and matrix theory, an upper bound for maximum tolerable input-delay is given in terms of the relationship with scaling strengths and largest eigenvalue of the Lapalician matrix. Simulation results are provided to illustrate the obtained results.     

Optimal Switching Integrity Attacks on Sensors in Industrial Control Systems

In this article, an optimal switching integrity attack problem is investigated to study the response of feedback control systems under attack. The authors model the malicious attacks on sensors as additive norm bounded signals. The authors consider an attacker who is only capable of launching attacks to limited number of sensors once a time and changing the combinations of attacked sensors all over the time. The objective of this paper is to find the optimal switching sequence of these combinations and the optimal attack input. The authors solve this problem by transforming it into a traditional optimal control problem with new control variables vary continuously in the range [0, 1]. The optimal solutions of the new control variables are of bang-bang-type. Therefore, an algebraic switching condition and an optimal attack input can be obtained. Finally, numerical results are provided to illustrate the effectiveness of the methods.     

Attack and Defense Strategies in Complex Networks Based on Game Theory

To investigate the attack and defense strategies in complex networks, the authors propose a two-player zero-sum static game model with complete information which considers attack and defense strategies simultaneously. The authors assume that both the attacker and defender have two typical strategies: Targeted strategy and random strategy. The authors explore the Nash equilibriums of the attacker-defender game and demonstrate that when the attacker's attack resources are not so significantly abundant as the defender's resources, there exists a pure-strategy Nash equilibrium in both model networks and real-world networks, in which the defender protects the hub targets with large degrees preferentially, while the attacker prefers selecting the targets randomly. When the attack resources are much higher than defense resources, both the attacker and the defender adopt the targeted strategy in equilibriums. This paper provides a new theoretical framework for the study of attack and defense strategies in complex networks.     

机构投资者羊群行为的演化博弈分析

进行股票市场上机构投资者羊群行为的演化博弈分析,研究结果发现:机构投资者做出投资决策时相互模仿产生的羊群行为不仅受到声誉、报酬等传统因素的影响,而且受到不同投资策略所带来的相对收益、机构投资者被对手跟随所遭受的损失等因素的影响,且随其支付结构的变化而变化.     

有限使用寿命情形下局内设备的赁购决策

局内设备赁购模型(RBP)是局内问题中被广泛研究和应用的经典模型。但在该模型以往的研究中,都假设设备的使用寿命无限长,这导致了模型本身的一些不足。为此,提出了有限使用寿命情况下的局内设备赁购模型。研究意外地发现,考虑设备寿命后,最优策略组合中可能不存在购买行为(M<2 N时),这在经典设备赁购模型中是不可能的;在考虑了设备寿命之后,租赁方的最优决策将与出租方的利润有关,这也是经典模型所忽略的。最后,对有限寿命设备赁购模型的经济意义和具体应用进行了说明。     

Homologous fault monitoring technology of redundant INS in airborne avionics systems

Redundant technology plays an important role in improving the reliability and fault-tolerance of the airborne avionics systems. A Markov state transition model is introduced to the reliability analysis of the redundant inertial navigation system （RINS） in airborne navigation systems. An information processing mechanism based on difference filtering is put forward to strengthen the consistency between the outputs of the equal-precision inertial navigation system （INS）. On this basis, the homologous fault monitoring algorithm is designed to realize the homologous fault monitoring of RINS. The simulation is carried out based on the above algorithms, and the results verify the effectiveness of the proposed fault monitoring algorithm based on difference filtering. Research results have good reference value for the configuration and design of RINS in airborne integrated avionics systems.     

Isogeometric Analysis-Based Topological Optimization for Heterogeneous Parametric Porous Structures

Porous structures widely exist in nature and artifacts, which can be exploited to reduce structural weight and material usage or improve damage tolerance and energy absorption. In this study,the authors develop an approach to design optimized porous structures with Triply Periodic Minimal Surfaces(TPMSs) in the framework of isogeometric analysis(IGA)-based topological optimization.In the developed method, by controlling the density distribution, the designed porous structures can achieve the opt...