Development of silver nanorod array based fiber optic probes for SERS detection

The development of intrinsic SERS fiber optic sensors, i.e., fiber optical sensors that also serve as SERS active platforms, is challenging in that an easy, robust method that integrates the SERS active platform with fiber optics is still largely missing. There is a trade-off between implementing optimal morphology of SERS active nanostructures for best enhancement effect and preserving optical transparency that allows maximum transmission of the excitation radiation and the detected signals. In the present work, highly sensitive and reproducible silver nanorod arrays (AgNRs) have been integrated to a fiber optic probe for SERS detection. The films underlying the AgNR coating have been tailored to allow maximum light transmission while maintaining optimal SERS activity. The intense spectral background from the probe fiber core is largely eliminated by using a GRIN lens to produce a tight focus of the incident radiation at the AgNR coating. The performance of the AgNR fiber optic probes has been evaluated in a forward scattering optical configuration using BPE and adenine. The low detection limit of BPE and adenine is 10⁻⁷ M. Reproducibility and sampling methods are also discussed.     

Large-area Raman enhancement substrates using spontaneous dewetting of gold films and silver nanoparticles deposition

We present a cost-effective method for making large-area surface enhanced Raman scattering (SERS) substrates by using spontaneous dewetting of ultrathin gold film. The dewetting of 5-nm-thick gold film formed high-density gold islands ranged from 40 nm to 80 nm. The measured SERS signal was 5 times stronger than synthesised gold nanoparticles. The SERS signals can be further increased by depositing small silver nanoparticles on the dewetted film. The experimental results showed 5-nm-thick silver coating increased SERS signals up to 10 times. The calculations by finite-difference time-domain method verified such SERS enhancement originated from enhanced electric fields between gold islands and silver nanoparticles. In the application, we demonstrated an all-optical measurement of pH values in microfluidic devices by using SERS signals of para-mercaptobenzoic acid.     

Prospects and research issues in multi-dimensional all optical networks多维全光网技术研究与展望

Research into all optical network (AON) technology has been ongoing over the past decade, and new features are constantly being developed. The advantages of AON include large-bandwidth provisioning, lowlatency transmission and low energy consumption. The basic concept underlying AON is transmission of data signals entirely through the optical domain from source to destination nodes, with no optical-electrical-optical (O-E-O) conversion at intermediate nodes. The technologies used to implement AON have undergone a series of evolutions, which encompass time division multiplexing (TDM), frequency division multiplexing (FDM), and space division multiplexing (SDM). Multi-dimensional AON (MD-AON), which leads the trend of AON’s future architecture, provides a vibrant state for emerging applications such as cloud computing and Internet of Things (IoT). In this article, we review the evolution of AON architectures based on the different all optical switching and multiplexing technologies (i.e., TDM, FDM, and SDM), which is one of the main areas of focus in this article. The other main area is detailed discussion of implementations such as data plane and control plane technologies as well as resource optimization technologies for realizing AON. We also introduce several AON testbeds with their compositions and functions, and some potential application scenarios that can be implemented based on these testbeds     

Optofluidic SERS: synergizing photonics and microfluidics for chemical and biological analysis

Surface enhanced Raman spectroscopy (SERS) leverages the specificity of Raman scattering and the sensitivity provided by localized plasmonic effects for applications in chemical and biomolecular detection. However, nearly four decades after the first report of SERS, practical uses of the technique remain limited. Optofluidic SERS??the synergistic use of microfluidics to improve the performance of SERS??may finally lead to practical devices for chemical and biomolecular detection. In this review, we describe recent advances in optofluidic SERS microsystems that have been developed to improve the performance and applicability of SERS. These techniques include designs that improve the light?Canalyte interaction, that perform active or passive concentration of metal nanoparticles and/or analyte molecules, and that utilize microfluidic techniques to improve functionality. In addition, we present optofluidic SERS techniques that enable new applications that have not been possible before the advent of optofluidics. Finally, we project future advances in optofluidic SERS and present a vision for the disruptive technologies that will enable the translation of SERS from the research lab to practical uses.     

入侵检测技术的研究与进展

入侵检测系统(IDS)作为一门新兴的安全技术，是网络安全系统中的重要组成部分。该文阐述了入侵检测系统的基本原理和功能模块，从数据源、检测方法和检测定时三个方面描述了入侵检测系统的分类，并对目前国内外入侵检测技术的研究现状作了介绍和分析。随着计算机技术和网络技术的高速发展，海量存储和高带宽的传输技术，都使得集中式的入侵检测越来越不能满足系统需求。由此指出，分布式入侵检测(DID)必将逐渐成为入侵检测乃至整个网络安全领域的研究重点，为进行入侵检测技术的研究提供一定的技术和理论依据。     

Optofluidic waveguides: I. Concepts and implementations

We review recent developments and current status of liquid-core optical waveguides in optofluidics with emphasis on suitability for creating fully planar optofluidic labs-on-a-chip. In this first of two contributions, we give an overview of the different waveguide types that are being considered for effectively combining micro and nanofluidics with integrated optics. The large number of approaches is separated into conventional index-guided waveguides and more recent implementations using wave interference. The underlying principle for waveguiding and the current status are described for each type. We then focus on reviewing recent work on microfabricated liquid-core antiresonant reflecting optical (ARROW) waveguides, including the development of intersecting 2D waveguide networks and optical fluorescence and Raman detection with planar beam geometry. Single molecule detection capability and addition of electrical control for electrokinetic manipulation and analysis of single bioparticles are demonstrated. The demonstrated performance of liquid-core ARROWs is representative of the potential of integrated waveguides for on-chip detection with ultrahigh sensitivity, and points the way towards the next generation of high-performance, low-cost and portable biomedical instruments.     

基于．NET气门尺寸检测系统软件架构设计

光学非接触检测是随着机械制造技术、计算机视觉技术、图像处理技术等发展而出现的新兴检测技术。传统人工手段对气门尺寸的检测往往存在效率低、可靠性差、检测精度不高、成本高、容易出错等弊端,采用光学非接触检测技术不仅可以提高检测的效率、精度和可靠性,同时可以降低成本和出错率。文中在阐述了系统的硬件结构和基本工作原理的基础上,通过分析实际生产需求,结合．NET技术框架,提出了符合实际需求的检测系统总体架构,并开发了汽车发动机气门尺寸自动检测系统,实现了系统各个功能模块并合理地解决了模块之间的联系,通过高精度算法检测出零件参数。该系统已应用于实际生产中,取得不错的效果。     

Tracing Malicious Relays in Cooperative Wireless Communications

A cooperative communication system explores a new dimension of diversity in wireless communications to combat the unfriendly wireless environment. While this emerging technology is promising in improving communication quality, some security problems inherent to cooperative relay also arise. This paper investigates the security issues in cooperative communications under the context of multiple relay nodes using decode-and-forward strategy, where one of the relay nodes is adversarial and tries to corrupt the communications by sending garbled signals. We show that the conventional physical-layer signal detector will lead to a high error rate in signal detection in such a scenario, and the application-layer cryptography alone will not be able to distinguish the adversarial relay from legitimate ones. To trace and identify the adversarial relay, we propose a cross-layer tracing scheme that uses adaptive signal detection at the physical layer, coupled with pseudorandom tracing symbols at the application layer. Analytical results for tracing statistics as well as experimental simulations are presented to demonstrate the effectiveness of the proposed tracing scheme     

模糊测试技术研究综述

随着人们对软件系统安全问题关注度的不断提升,模糊测试作为一种用于安全漏洞检测的安全测试技术,具有自动化程度高、误报率低等优点,其应用越来越广泛,地位也越来越重要。经过近些年的不断改进,模糊测试无论在技术发展上还是在应用创新上,都取得了诸多成就。首先,对模糊测试的相关概念和基本理论进行简要说明,总结了模糊测试在各领域的应用情况,针对不同领域的漏洞挖掘需求,分析得出相应的模糊测试解决方案。其次,重点总结了近几年来模糊测试的重要发展成果,包括测试工具、框架、系统及方法的改进与创新,并分析总结了各发展成果所采用的创新方法,提出的理论以及各工具、系统的优点与不足。最后,分别从协议逆向工程应用、云平台建设、新兴技术结合、模糊测试对抗技术研究及模糊测试工具集成的角度,为模糊测试下一步的研究提供了方向参考。     

RFID复杂事件处理关键技术的研究与改进

RFID复杂事件处理是一个新兴的技术领域,它用来处理大量的简单事件,并从中整理出有价值的事件。RFID事件和传统的事件相比较具有海量性、空间性和时间性、数据不准确性等特征。文中在分析RFID数据特点的基础上,对RFID复杂事件处理的关键技术进行研究和改进,主要介绍RFID数据的清洗和事件检测技术。对于RFID数据清洗部分,提出了多层次过滤的方法使得到的数据更接近真实情况,而事件检测方面则提出了局部检测和全局检测相结合的方法对相关数据进行检测以得到更有意义的数据供上层应用使用。最后,对RFID复杂事件处理的发展趋势做出展望。     

光声显微成像技术的研究进展

光声成像作为一种兼具高光学对比度和大超声探测深度的新兴成像方法,突破了传统光学成像技术分辨率与成像深度相互制约的壁垒,获得了空前快速的发展,其中,光声显微成像技术继承了光声成像技术的优点,采用声学或光学聚焦的成像模式,可以实现高对比度、高分辨率的生物组织结构、分子与功能成像,在神经学、眼科、血管生物学和皮肤学等研究领域具有潜在应用价值。为此,首先介绍了光声成像技术的原理和分类,然后围绕光声显微成像(Photoacoustic microscopy, PAM)技术这一主题,重点综述了新型PAM技术的发展情况、PAM焦深（Depth of focus, DoF）延拓技术以及PAM的生物医学应用。最后,总结了PAM技术发展存在的挑战,并对未来发展方向进行了展望。     

Cyber Security Intrusion Detection for Agriculture 4.0: Machine Learning-Based Solutions,Datasets, and Future Directions

In this paper, we review and analyze intrusion detection systems for Agriculture 4.0 cyber security. Specifically, we present cyber security threats and evaluation metrics used in the performance evaluation of an intrusion detection system for Agriculture 4.0. Then, we evaluate intrusion detection systems according to emerging technologies, including, Cloud computing, Fog/Edge computing, Network virtualization, Autonomous tractors, Drones, Internet of Things, Industrial agriculture, and Smart Grids. Based on the machine learning technique used, we provide a comprehensive classification of intrusion detection systems in each emerging technology. Furthermore, we present public datasets, and the implementation frameworks applied in the performance evaluation of intrusion detection systems for Agriculture 4.0. Finally, we outline challenges and future research directions in cyber security intrusion detection for Agriculture 4.0.      

Real-time optical markerless tracking for augmented reality applications

Augmented reality (AR) technology consists in adding computer-generated information (2D/3D) to a real video sequence in such a manner that the real and virtual objects appear coexisting in the same world. To get a realistic illusion, the real and virtual objects must be properly aligned with respect to each other, which requires a robust real-time tracking strategy—one of the bottlenecks of AR applications. In this paper, we describe the limitations and advantages of different optical tracking technologies, and we present our customized implementation of both recursive tracking and tracking by detection approaches. The second approach requires the implementation of a classifier and we propose the use of a Random Forest classifier. We evaluated both approaches in the context of an AR application for design review. Some conclusions regarding the performance of each approach are given.     

工业铸件缺陷无损检测技术的应用进展与展望

高端装备制造业是国民经济的支柱产业,是推动工业转型升级的引擎,发挥着举足轻重的作用.而铸造产业一直是人类现代生产生活中重要的、不可替代的产业,铸件产品既是工业制造产品,也是大型机械的组成部分.随着经济水平和工业自动化程度的不断提升,人们对于铸件的需求量呈指数爆炸式增长,铸件价值辐射到各行各业.与此同时,铸件在铸造、服役...     

光纤传感技术在物联网中的应用

现如今,物联网已经发展成为了一个研究热点,而光纤传感技术在物联网的发展中也得到了广泛的应用,并引起了广泛的关注。物联网的核心部件为传感器,特别是光纤传感器,它和其它的类型的传感器所不具有的优势,而物联网主要有四个技术构层,它们是应用接口、数据处理技术、数据传输网络和传输网络,在物联网中我们将会看到有大量的各种各样的传感器的存在,这些传感器可以用来感知不同的环境参数,比如温度、重力、光电、声音、震动和位移,这些传感器为物联网提供最原始的数据信息。当前,光纤传感技术在物联网中的应用引起社会各界的高度关注。本文主要对物联网的界定、构成以及光纤传感器的原理和发展现状进行了深入的探讨和分析,并且重点是对光纤传感技术在物联网中的应用加以详细阐述。希望可以通过本文的论述,能够对今后光纤传感技术在物联网中的应用产生一些积极影响。     

Information systems and uncertainty: a conspiracy of misplaced confidence

Abstract. Information technology is becoming an increasingly important factor in contemporary management. Information systems are being set up in business explicitly to accommodate the new opportunities of this technology, and these are having a lasting effect on managerial practice. The full implications of this technology-driven development have not been appreciated by organizations, which in absorbing technological systems, are tolerating a great drain on their resources.
The efficacy of computers is predicated on the acceptance of some very specific perspectives. A growing discontent and disappointment with their limited achievements is our reason for advocating a different point of view. We will discuss how a shift in perspective, particularly in respect to the perception of uncertainty, will affect thinking and practice in the field of management support systems. We will render our view of the application of computerized decision support systems (DSS), and especially, we will focus on the beliefs and assumptions that have shaped this technology thus far. To this end we will discuss the concept of uncertainty, by juxtaposing current thinking and practice with our understanding of the context of its application. Finally, we will place our understanding of uncertainty in a managerial context and explain the implications this would have for strategists.     

SAR图像道路网提取方法综述

SAR图像道路网提取具有重要的遥感应用价值.20多年来,随着SAR成像技术的不断发展以及遥感应用的迫切需求,涌现出大量道路网提取方法.本文回顾了SAR图像道路网提取研究的发展历程,从道路提取流程阶段出发,将其分为局部检测和全局连接这两大步骤,在每个步骤中分析比较了现有算法的适用范围及相对优缺点,指出了当前研究中存在的问题,展望了SAR图像道路网提取的发展趋势.     

Optical mapping and nanocoding approaches to whole-genome analysis

Recent application of microfluidic and nanofluidic approaches to genomics has enabled rapid analysis of whole human and other large genomes. Here, we present a review of optical mapping and nanocoding, two single-molecule whole-genome analysis systems, which are used for physical mapping of genomes. Optical mapping employs a microfluidic device, fabricated using soft lithography approaches, to achieve DNA presentation via DNA flow in microchannels. On the other hand, nanocoding leverages DNA confinement in nanoscale devices to achieve DNA presentation. In this review, we focus on the physical principles underlying DNA presentation in both of these systems and the application of these approaches towards better understanding of genomic structure and structural variation.     

微流控芯片技术在心肌标志物检测中的应用综述

心肌标志物的检测异常,是急性心肌梗死的重要诊断指标之一。对心肌标志物的监测可直接影响心血管疾病患者的临床诊断、危险分层、治疗方案选择和预后判断。微流控芯片集进样、预处理、分离和检测于一体,具有样品需求量小、便携、分析快速等特点,是理想的心肌标志物检测平台。文章根据检测方法的不同,综述了近年来利用微流控芯片平台对心肌标志物的检测。已有检测方法中主要是光学和电学方法。随着传感器技术的发展,更多检测方法被采用。通过及时的综述概括,既可对已有技术和方法起到归纳作用,又可促进微流控芯片在心肌标志物即时诊断领域的发展。     

On-road vehicle detection: a review

Developing on-board automotive driver assistance systems aiming to alert drivers about driving environments, and possible collision with other vehicles has attracted a lot of attention lately. In these systems, robust and reliable vehicle detection is a critical step. This paper presents a review of recent vision-based on-road vehicle detection systems. Our focus is on systems where the camera is mounted on the vehicle rather than being fixed such as in traffic/driveway monitoring systems. First, we discuss the problem of on-road vehicle detection using optical sensors followed by a brief review of intelligent vehicle research worldwide. Then, we discuss active and passive sensors to set the stage for vision-based vehicle detection. Methods aiming to quickly hypothesize the location of vehicles in an image as well as to verify the hypothesized locations are reviewed next. Integrating detection with tracking is also reviewed to illustrate the benefits of exploiting temporal continuity for vehicle detection. Finally, we present a critical overview of the methods discussed, we assess their potential for future deployment, and we present directions for future research.