A multilevel sampled‐data approach for resilient navigation and control of autonomous systems

Autonomous systems are rapidly becoming an integrated part of the modern life. Safe and secure navigation and control of these systems present significant challenges in the presence of uncertainties, physical failures, and cyber attacks. In this paper, we formulate a navigation and control problem for autonomous systems using a multilevel control structure, in which the high‐level reference commands are limited by a saturation function, whereas the low‐level controller tracks the reference by compensating for disturbances and uncertainties. For this purpose, we consider a class of nested, uncertain, multiple‐input–multiple‐output systems subject to reference command saturation, possibly with nonminimum phase zeros. A multirate output‐feedback adaptive controller is developed as the low‐level controller. The sampled‐data (SD) design of this controller facilitates the direct implementation on digital computers, where the input/output signals are available at discrete time instances with different sampling rates. In addition, stealthy zero‐dynamics attacks become detectable by considering a multirate SD formulation. Robust stability and performance of the overall closed‐loop system with command saturation and multirate adaptive control are analyzed. Simulation scenarios for navigation and control of a fixed‐wing drone under failures/attacks are provided to validate the theoretical findings.     

基于聚类的数据加权优化在犯罪预测中的应用

近年来，我国传统暴力犯罪与成年人犯罪呈下降态势，但是，犯罪案由层出不穷。为有效提升公安实践工作中犯罪预测能力，打击各类违法犯罪事件,本文针对犯罪数据，提出一种新型犯罪预测模型。利用密度聚类分析方法将犯罪数据分类，然后进行数据降维提取关键属性生成特征数据，继而对特征数据进行加权优化并采用机器学习的方式对特征数据进行学习，从而预测犯罪案由。实验结果表明，与传统方法相比，本文方法具有更好的预测效果，为公安实践工作中类似案件的侦破和预防，提供新的路径支撑。     

Quantitative Analysis of Crime Incidents in Chicago Using Data Analytics Techniques

In this paper we aim to identify certain social factors that influence, and thus can be used to predict, the occurrence of crimes. The factors under consideration for this analytic are social demographics such as age, sex, poverty, etc., train ridership, traffic density and the number of business licenses per community area in Chicago, IL. A factor will be considered pertinent if there is high correlation between it and the number of crimes of a particular type in that community area.     

Packet loss detection in networked control systems

One of the main issues related to the reliable operation of network control systems concerns the design of mechanisms able to detect anomalies in the functioning of the communication network through which the control loops are closed. In this article, we address the problem of detecting the occurrence of packet losses and design a mechanism that can detect the occurrence of packet losses directly from process sensor data. Specifically, we propose a moving‐horizon estimation scheme that permits to detect if the packet‐loss rate exceeds prescribed thresholds, which are representative of stability and performance of the control system. We discuss theoretical properties of the proposed solution along with an approximation scheme with reduced computational burden. A numerical example is discussed to substantiate the analysis.     

基于节点1-邻居图相似性的社会网络匿名技术

利用传统的k匿名技术在社会网络中进行隐私保护时会存在聚类准则单一、图中数据信息利用不足等问题. 针对该问题, 提出了一种利用Kullback-Leibler (KL)散度衡量节点1-邻居图相似性的匿名技术(anonymization techniques for measuring the similarity of node 1-neighbor graph based on Kullback-Leibler divergence, SNKL). 根据节点1-邻居图分布的相似性对原始图节点集进行划分, 按照划分好的类进行图修改, 使修改后的图满足k匿名, 完成图的匿名发布. 实验结果表明, SNKL方法与HIGA方法相比在聚类系数上的改变量平均降低了17.3%, 同时生成的匿名图与原始图重要性节点重合度保持在95%以上. 所提方法在有效保证隐私的基础上, 可以显著的降低对原始图结构信息的改变.     

论以欺诈方式出售已抵押房屋的刑法适用

房地产开发商隐瞒房屋已经抵押的事实、采取欺诈方式销售房屋的行为,侵犯了房屋买受人的合法权益,扰乱了诚实信用的市场秩序.把这种行为引入到刑法的调整范围,通过追究犯罪人的刑事责任,可以增加违法成本,规范开发商以欺诈手段销售已抵押房屋的行为.该种行为符合合同诈骗罪的构成要件,有必要在司法解释中予以明确.     

中关村信息产业专门化街区的建构

通过对中关村“电子一条街”城市空间和景观演化的分析，初步讨论了信息产业专门化街区形成的原因。通过对信息产业专门化街区构成要素以及要素间邻近度的分析，总结了信息产业专门化街区的发展趋势，并在此基础上提出了“电子街区”的规划结构图。     

合理的景观设计抵制城市死角达到犯罪预防——以上海市徐家汇某高架公园环境分析为例

城市化进程不仅改变了传统土地组织结构与社会文化，也导致了日益严重的都市犯罪问题．特别是有些大城市随着城市发展出现了“城市死角”。该文主要探讨以合理的设计手法来倡导符合具体都市功能的环境设计，达到预防犯罪的目的，抵制城市死角。研究选取上海市典型的高架桥底舟固为模型，找出较为合理的设计通用手法来处理高架公园问题，旨在尽可能地使用城市集约空间，消除城市“死角”现象，     

The Impact of Single-family Mortgage Foreclosures on Neighborhood Crime

Foreclosures of single-family mortgages have increased dramatically in many parts of the US in recent years. Much of this has been tied to the rise of higher-risk subprime mortgage lending. Debates concerning mortgage regulation, as well as around other residential finance policies and practices, hinge critically on the social as well as personal costs of loan default and foreclosure. This paper examines the impact of foreclosures of single-family mortgages on levels of violent and property crime at the neighborhood level. Using data on foreclosures, neighborhood characteristics, and crime, the study found that higher foreclosure levels do contribute to higher levels of violent crime. The results for property crime are not statistically significant. A standard deviation increase in the foreclosure rate (about 2.8 foreclosures for every 100 owner-occupied properties in one year) corresponds to an increase in neighborhood violent crime of approximately 6.7 per cent. The policy implications of these findings are discussed.     

军用机场智慧场务保障系统架构

为解决传统场务保障系统因缺乏广泛互联互通互操作而存在协调不充分的问题,建立军用机场智慧场务保障系统架构.将云计算和信息物理系统(cyber-physical systems,CPS)概念引入场务保障系统,对智慧场务保障系统架构进行研究,分析智慧场务保障系统的基本内涵与系统架构建设需求,诠释架构中各层次功能和特点.结果表明:该架构具有强大的信息处理能力、按需弹性的服务模式、高效的协同控制等优势,能提升场务保障系统的智慧化、信息化水平.