自适应空域矩阵滤波器设计和目标方位估计

针对在强干扰背景中检测弱目标信号时被动声信号处理技术的性能会严重降低的问题,提出了一种自适应空域矩阵滤波器的设计方法。该方法是在保证滤波器通带响应与期望响应误差和阻带响应低于某设定值的条件下,最小化滤波后基阵的输出功率,使得滤波器能尽量保证让通带扇面的信号无失真通过,同时抑制阻带扇面的干扰和噪声。将滤波器的优化设计问题表达成二阶锥规划的形式,利用已有的内点方求出其数值解。最后将设计的自适应空域矩阵滤波器用于强干扰背景中弱目标信号的方位估计。计算机仿真结果说明,所提方法能在干扰方位形成零陷,有效地抑制阻带区域的强干扰,提高了后续方位估计方法的性能。     

基于子空间的后验稀疏约束迭代DOA估计方法

子空间波达方向 (DOA)估计方法的一个缺点是在子空间分解过程中难以利用信号的相关信息或有关DOA估计的先验信息改善DOA估计的性能。结合子空间方法和协方差矩阵拟合方法 ,利用信号相关信息和DOA估计的稀疏约束信息 ,研究了一种新的不相关窄带信号DOA估计方法。理论分析和仿真实验结果表明 ,这种迭代DOA估计方法一般经过几次迭代就能获得稳定的高分辨率DOA估计。     

A Non-Convex Optimization Approach to Dynamic Coverage Problem of Multi-agent Systems in an Environment with Obstacles

In this paper, a cooperative region reconnaissance problem is investigated where a group of agents are required to fly across and detect events occur in an environment with static obstacles until an effective coverage is achieved. First, the region reconnaissance is formulated as a non-convex optimization problem. A coverage performance index with additional collision and obstacle avoidance constraints is given. Since the optimization index is an implicit function of state variables and cannot be used to compute gradients on state variables directly, an approximate optimization index is selected.Then, a non-convex optimization-based coverage algorithm is proposed to find the optimal reconnaissance location for each agent and guarantee no collisions trajectories among agents and obstacles.Finally, simulation experiments are performed to verify the effectiveness of the proposed approach.     

具有估计误差方差约束的连续时间卡尔曼滤波新方法

在状态估计应用领域。指标要求常常表现为估计误差稳态方差的上界形式。本文考虑连续系统在动态特性及稳态误差方差约束下的卡尔曼滤波问题，即设计滤波增益，使滤波矩阵具有给定的稳定裕度，同时各状态分量的估计误差稳态方差不大于各自预先给定值。基于代表方法，文中给出了期望滤波增益的存在条件及其解析表达式，并提供了说明性的数值算例。     

A Theory of the Risk for Empirical CVaR with Application to Portfolio Selection

When decisions are based on empirical observations, a trade-off arises between flexibility of the decision and ability to generalize to new situations. In this paper, we focus on decisions that are obtained by the empirical minimization of the Conditional Value-at-Risk(CVa R) and argue that in CVa R the trade-off between flexibility and generalization can be understood on the ground of theoretical results under very general assumptions on the system that generates the observations. The results have implications on topics related to order and structure selection in various applications where the CVa R risk-measure is used. A study on a portfolio optimization problem with real data demonstrates our results.     

Fuzzy Filter Design for Affine Systems with Sensor Faults: A Dynamic Event-Triggered Approach

This study addresses the issue of dynamic event-triggered-based filtering for fuzzy affine systems. To alleviate the utilization of constraint bandwidth resources and improve the efficiency of the signals exchange, a dynamic event-triggered protocol is forwarded to regulate the trigger instants with objective system states. Meanwhile, the nonhomogeneous Markov process is proposed to characterize the dynamic behaviors of sensor faults, where the time-varying transition probabilities belong to a c...     

Redesigning a Large Supply Chain Management System to Reduce the Government Administration: A Socio-Functional Systems Approach

Redesigning managerial structure and redefining managerial processes in a large supply chain network in national scale is the main focus in this study. The considered supply chain is mainly under governmental management. Reducing the role of the government in managing the supply chain is a strategy pursued in this study. The supply chain is approached as a socioeconomic system and a methodology is designed to address important aspects of the system. The methodology is divided into two streams addressing two main aspects of a socioeconomic system—functional and social. Organizational cybernetics is the core of functional stream. The SCOR model has been used as a well-accepted supply chain management tool alongside the viable system model. The Social stream benefits from ideas of the methods which are used in the soft systems methodology and interactive planning. The methodology is applied in the considered supply chain network in which the final product is chicken meat. While supply chain management is mostly approached from a functional viewpoint, this study also considers its social aspects. Using soft methods as well as functional methods result in a systemic design which is functionally and socially desirable.     

Method of Generating Strategic Guidance Information for Driving Evacuation Flows to Approach Safety-Based System Optimal Dynamic Flows: Case Study of a Large Stadium

In previous evacuation flow planning, a system optimal dynamic traffic assignment(SODTA) did not consider the exogenous costs caused by potential traffic accidents. A traffic accident,which might occur as a result of traffic congestion, will impact an evacuation process because of accidentrelated delays experienced by the downstream vehicles. This paper establishes a safety-based SO-DTA linear programming model in which the generalized system cost incorporates both the travel time and the accident-related delay. The goal is to minimize the generalized system cost under the cell transmission setup. Furthermore, the authors provide strategic guidance information that considers both the objective of the decision maker and the route choice behavior of the evacuees. Mathematically,the authors propose an unconstrained non-linear programming model aimed at minimizing the gap between the safety-based flows and the stochastic real-world evacuation flows, to provide strategic travel time information to be published on variable message signs(VMS). In the case study, the authors found that the safety-based SO-DTA model can reduce congestion and improve the evacuation efficiency; the stochastic real-world evacuation flows, guided by strategic information, can approach the safety-based flows.     

Analytic and Dynamic Approach to Collaboration: A Transdisciplinary Case Study on Sustainable Landscape Development in a Swiss Prealpine Region

The involvement of stakeholders and the public in societal decision processes has lately received increased attention. We suggest that appropriate and tailored techniques should be selected and integrated to provide the prerequisites for inclusive involvement depending on the issue, type, goals and phase of the decision process in question, i.e. an analytic, systematic and dynamic approach to collaboration. In a transdisciplinary case study design we integrate diverse analytical methods whereby a process of mutual learning between science and people from outside academia is strived for. Our framework for collaboration is illustrated by a case study on sustainable landscape development in the Swiss prealpine region of Appenzell Ausserrhoden.

Yeperenye Dreaming in Conceptual,Geographical, and Cyberspace: A Participatory Action Research Approach to Address Local Governance Within an Australian Indigenous Housing Association

Systemic Practice and Action Research - This paper discusses work in progress with an Indigenous housing association in Central Australia. It builds on and extends a 2-year policy and planning...