雷达视频回波信号实时采集、压缩转发装置

介绍了一种基于FPGA和DSP的六通道雷达视频回波实时信号采集、压缩转发装置,该装置单通道采样率为20MSPS,采样精度为12bit,采集后的数据经过DSP压缩处理后再转化为2Mbps的PCM码流,实时发送给遥测发射机进行遥测下传和实时检测;并对相位一致性控制、基于流水线的数据处理方法等关键技术做了详细介绍;该装置已成功应用于某飞行器综合匹配试验,其性能和指标均优于应用要求。     

Stable local dimensionality reduction approaches

Dimensionality reduction is a big challenge in many areas. A large number of local approaches, stemming from statistics or geometry, have been developed. However, in practice these local approaches are often in lack of robustness, since in contrast to maximum variance unfolding (MVU), which explicitly unfolds the manifold, they merely characterize local geometry structure. Moreover, the eigenproblems that they encounter, are hard to solve. We propose a unified framework that explicitly unfolds the manifold and reformulate local approaches as the semi-definite programs instead of the above-mentioned eigenproblems. Three well-known algorithms, locally linear embedding (LLE), laplacian eigenmaps (LE) and local tangent space alignment (LTSA) are reinterpreted and improved within this framework. Several experiments are presented to demonstrate the potential of our framework and the improvements of these local algorithms.     

A decision support system for fisheries management using operations research and systems science approach

In this paper, we present a general framework, using a systems science approach, for developing a decision support system (DSS) for fisheries management. Decision support systems are quantitative tools for managers to evaluate outcomes of their policies prior to implementation. Our fishery model considers multiple stocks and fisheries simultaneously in balancing catch among targeted and protected fish abundances. Since in the Northeastern US multispecies fishery the distribution of abundance, catch-per-unit-effort and bycatch vary geographically, we focus on a spatial management approach to address their spatial variability. The core component of this DSS applies operations research techniques of simulation and optimization to determine the optimal inter-annual and intra-annual fishing plans in terms of fishing efforts in each sub-area and the time period. The result is the recommended amount to catch from each fish species at each sub-area at any time period so that while management objectives for sustainability of fish stocks are satisfied, the value of landings is maximized. The graphical user interface of the proposed DSS helps users to define inputs, to set constraints and sub-area boundaries, and to visualize the outcomes.     

高速电磁阀的动态特性

高速电磁阀是重要的液压执行元件,因此其响应速度尤为重要.首先分析高速电磁阀的原理结构,再对电学、磁学、运动学进行建模,研究不同参数下系统的响应速度与时间的关系.研究结果表明:采用的控制变量仿真法可以清晰地看出不同参数对系统动态参数的影响,其中起励电压、线圈匝数与占空比对响应的影响比较明显,为项目研究提供参考.     

智能磁致伸缩液位测量仪设计

针对当前液位测量监测系统中存在的多种问题,设计了一种高精度的智能磁致伸缩液位测量仪.系统采用ARM Cortex-M4系列的EK-TM4C1294NCPDTI芯片作为核心控制处理器,包含电源模块、时钟模块、激励信号模块、信号检测模块、以太网接口模块、故障报警模块、数据存储模块等.实现了测量精度高、稳定性好、人机交互友好,具有网络化通信功能的智能液位测量仪.     

基于混合聚类的城市道路多时段控制研究*

多方案控制具有简单实用、可靠性好,稳定性高,性价比高等的优点,在城市交通控制中得到了广泛应用。本研究在利用指数平滑异同移动平均法对缺失交通数据进行修补的基础上,运用快速聚类与系统聚类相结合的混合聚类方法对交通数据进行分析,并以经典的Silhouttte评价指标作为聚类终止条件,同时兼顾/考虑了交通数据时序性,消除聚类结果中的三类“奇异点”,最后利用交通信号配时软件SYNCHRO制定了相应时段的控制方案。相关的案例分析显示,优化后的多时段控制方案可以更好地适应交通流的波动,车均延误减少9.79%,其中时序性考虑可以有效改善控制方案频繁切换对交通流的扰动,避免其负效应对混合聚类改善效果的影响。     

基于小波滤波背景预测的红外弱小目标检测方法

红外弱小目标检测是红外图像研究领域的热点与难点。有效地从背景中检测出弱小目标对于后续的跟踪、识别工作具有十分重要的意义。针对现有检测方法的不足,提出了一种基于小波滤波背景预测的红外弱小目标检测方法。该方法利用小波滤波去噪的优良特性将目标作为噪声滤除,然后构建近似的前景分布图与背景分布图,最后基于连通体筛选与对比度门限完成弱小目标的提取。采用实测光电图像对该方法进行了验证,结果表明,提出的方法能够有效抑制噪声,完成背景预测以及红外弱小目标的检测。     

An interactive approach based on a discrete differential evolution algorithm for a class of integer bilevel programming problems

This paper presents an interactive approach based on a discrete differential evolution algorithm to solve a class of integer bilevel programming problems, in which integer decision variables are controlled by an upper-level decision maker and real-value or continuous decision variables are controlled by a lower-level decision maker. Using the Karush--Kuhn–Tucker optimality conditions in the lower-level programming, the original discrete bilevel formulation can be converted into a discrete single-level nonlinear programming problem with the complementarity constraints, and then the smoothing technique is applied to deal with the complementarity constraints. Finally, a discrete single-level nonlinear programming problem is obtained, and solved by an interactive approach. In each iteration, for each given upper-level discrete variable, a system of nonlinear equations including the lower-level variables and Lagrange multipliers is solved first, and then a discrete nonlinear programming problem only with inequality constraints is handled by using a discrete differential evolution algorithm. Simulation results show the effectiveness of the proposed approach.     

A commentary and correction on the article “Pansharpening by exploiting sharpness of the spatial structure”

This study clarifies the implicit potential deficiency caused by the sparse cardinality parameter k in Rong et al. (2014). In addition, k = β × W × M × N (0.9 ≤ β < 1) is suggested to avert this potential deficiency, where β is a ratio controlling the amount of sparse cardinality, W is the number of multispectral bands and M × N is the size of panchromatic image. With the choice of k suggested in this study, the low rank matrix L and sparse matrix S obtained by Go Decomposition (Zhou and Tao 2011) can be iteratively optimized and solved. Thus, instead of choosing k as W × M × N in Rong et al. (2014), the potential deficiency that L is directly obtained as an analytic solution can be averted.