Single step micro‐patterned liquid crystal photoalignment by patterned quarter‐wave plate

In this article, a method for fabricating the patterned liquid crystal photoalignment structures, in a single step, is proposed. A patterned quarter‐wave plate formed by a photoaligned liquid crystalline polymer film is used as a photomask to generate photoaligned micro‐patterns. Whereas other existing alternatives include complicated fabrication scheme, the proposed method provides an edge with simple one‐step alignment. Moreover, the proposed method offers highly accurate, high resolution, multi micro‐pattern alignment with great repeatability and therefore could find application in wide range of photonic and display devices demanding the micro‐patterned, single of multi domain, alignment. In addition, the structure could be used for optical polarization information storage and patterned alignment structure storage, which could easily be reproduced.     

适于软硬件实现的安全轻量S盒的设计

随着物联网的发展,轻量级分组密码算法的设计显得尤为重要。S盒是对称密码算法的关键部件。许多加密算法的硬件实现过程易受侧信道攻击,门限实现是一种基于秘密共享和多方计算的侧信道攻击对策。通过简单地对三次布尔函数中的变量进行循环移位,构建密码性质最优的4×4安全轻量S盒,并且为所构造的S盒设计了门限实现方案来抵御侧信道攻击,该方案是可证安全的。该方法构造的S盒的四个分量函数的实现电路相同,极大地降低了硬件实现的复杂度。给定S盒的一个分量,其余的三个分量可通过该分量的循环移位获得,这样大大降低硬件实现成本,易于快速软件实现。     

Dependability enhancing mechanisms for integrated clinical environments

In this article, we present a set of lightweight mechanisms to enhance the dependability of a safety-critical real-time distributed system referred to as an integrated clinical environment (ICE). In an ICE, medical devices are interconnected and work together with the help of a supervisory computer system to enhance patient safety during clinical operations. Inevitably, there are strong dependability requirements on the ICE. We introduce a set of mechanisms that essentially make the supervisor component a trusted computing base, which can withstand common hardware failures and malicious attacks. The mechanisms rely on the replication of the supervisor component and employ only one input-exchange phase into the critical path of the operation of the ICE. Our analysis shows that the runtime latency overhead is much lower than that of traditional approaches.     

Static characterization of microstructures using AOMSI and temporal phase-shifting (TPS) methods

Temporal phase shifting interferometry is the most common method for characterization of surface, profile and displacement properties of micro devices. Common methods of phase shifting require piezoelectric material based devices that have inherent errors due to non-linearity. To avoid these errors during phase shifting, a new phase shifting technique is presented in this work. This technique utilizes the advantage of stroboscopic interferometry to create phase shifted images without requiring any additional component for phase shifting. The proposed method was used for surface profiling and static characterization of the microstructures. Static characterization was performed to identify the tip deflection and profile variation of the microcantilever in response to various DC voltages. A capacitor-based cantilever was tested under varied electrostatic loads and the deflection of the cantilever was extracted using the proposed method. The deflection of the cantilever was predicted using energy method. Static characterization results from the proposed technique were found to be in good agreement with the predicted results.     

Crashworthiness design of multi-component tailor-welded blank (TWB) structures

Crashworthiness of tailor-welded blank (TWB) structures signifies an increasing concern in lightweight design of vehicle. Although multiobjective optimization (MOO) has to a considerable extent been successfully applied to enhance crashworthiness of vehicular structures, majority of existing designs were restricted to single or uniform thin-walled components. Limited attention has been paid to such non-uniform components as TWB structures. In this paper, MOO of a multi-component TWB structure that involves both the B-pillar and inner door system subjected to a side impact, is proposed by considering the structural weight, intrusive displacements and velocity of the B-pillar component as objectives, and the thickness in different positions and the height of welding line of B-pillar as the design variables. The MOO problem is formulated by using a range of different metamodeling techniques, including response surface methodology (RSM), artificial neural network (ANN), radial basis functions (RBF), and Kriging (KRG), to approximate the sophisticated nonlinear responses. By comparison, it is found that the constructed metamodels based upon the radial basis function (RBF, especially multi-quadric model, namely RBF-MQ) fit to the design of experiment (DoE) checking points well and are employed to carry out the design optimization. The performance of the TWB B-pillar and indoor panel system can be improved by optimizing the thickness of the different parts and height of the welding line. This study demonstrated that the multi-component TWB structure can be optimized to further enhance the crashworthiness and reduce the weight, offering a new class of structural/material configuration for lightweight design.     

The effects of source resolution on resolution enhancement through shifted superimposition projection

Resolution in a projected display is traditionally defined by the number of pixels in the projector's spatial light modulator (SLM). In recent years, different techniques that increase the resolution on the screen above the number of SLM pixels have gained popularity. In one such technique, called pixel‐shifting or shifted‐superimposition, the display physically shifts every n^th frame on the projected screen, and the overlapping pixel grids forms a finer subpixel grid with a higher pixel count. There is still an open question how much this method increases the resolution and how to quantify it. The resolution on the screen also depends upon the resolution of the input image fed to the projector. In this work, we experimentally investigate how the projector performs with resolution enhancement through pixel‐shifting and how this method relates to the source resolution. We also investigate some known methods of resolution measurement and evaluate how these methods perform for the shifted‐superimposition case. We find that the resolution enhancement through shifted‐superimposition enhances the resolution to about 40% over native resolution, and we also find two different measurement methods (grille contrast and least resolvable line pair method) that is relevant for effectively measuring resolution within such systems.     

基于轻量级网络的人脸检测及嵌入式实现

尽管基于卷积神经网络(CNN)的人脸检测器在精度上已经有了很大提升,但所需的计算量和模型复杂度越来越高,如何在计算能力有限的嵌入式设备上应用人脸检测模型是一个很大的挑战.针对320×240分辨率输入图像的人脸检测在嵌入式系统上的应用问题,提出了一种基于轻量级网络的低分辨率人脸检测算法.该算法使用注意力机制、结合了Dis...     

用轻量级组件解决传统组件的性能问题的方法

提出了一种新的组件设计方法－轻量级组件架构，介绍了它的主要思想和具体实现方法，轻量级组件的方法克服了传统组件在构造大通信量的信息管理系统时的种种不足，有着广泛的应用前景。     

A lightweight framework for dynamic GUI data verification based on scripts

Runtime verification (RV) provides essential mechanisms to enhance software robustness and prevent malfunction. However, RV often entails complex and formal processes that could be avoided in scenarios in which only invariants or simple safety properties are verified, for example, when verifying input data in Graphical User Interfaces (GUIs). This paper describes S‐DAVER, a lightweight framework aimed at supporting separate data verification in GUIs. All the verification processes are encapsulated in an independent layer and then transparently integrated into an application. The verification rules are specified in separate files and written in interpreted languages to be changed/reloaded at runtime without recompilation. Superimposed visual feedback is used to assist developers during the testing stage and to improve the experience of users during execution. S‐DAVER provides a lightweight, easy‐to‐integrate and dynamic verification framework for GUI data. It is an integral part of the development, testing and execution stages. An implementation of S‐DAVER was successfully integrated into existing open‐source applications, with promising results. Copyright © 2015 John Wiley & Sons, Ltd.     

基于VD-MobileNet网络的WebAR生活垃圾分类信息可视化方法

随着我国垃圾分类制度的加速推行,基于虚拟/增强现实技术的垃圾分类应用大量涌现。受识别设备平台及居民应用习惯等方面的影响,针对目前该类应用在便捷性、实用性上存在较大不足,提出了一种基于轻量化神经网络并融合移动增强现实及可视化技术的垃圾分类应用方案。首先,提出了基于深度学习的垃圾分类可变扩张卷积VD-MobileNet模型方法能够解决移动设备中存在的计算能力有限、网络庞大等问题,通过在MobileNet模型中引入空洞卷积增加感受野、扩大垃圾的特征信息以提升分类精度,引入LeakyReLU激活函数优化网络的表达能力;其次,将该模型与WebAR技术结合,设计了一款面向移动设备的轻量级垃圾分类信息可视化系统,该系统具备跨平台特性,实现了对分类信息的多元化可视呈现,提供了灵活的交互方式。实验及评估表明,该VD-MobileNet模型在垃圾分类数据集中分类效果良好,能够在参数量不变的前提下有效减少计算量,此外结合该模型所设计的WebAR应用系统可为用户的垃圾处理事务提供合理有效地协助。     

深度可分离卷积和标准卷积相结合的高效行人检测器

行人检测器对算法的速度和精确度有很高的要求.虽然基于深度卷积神经网络(DCNN)的行人检测器具有较高的检测精度,但是这类检测器对硬件设备的计算能力要求较高,因此,这类行人检测器无法很好地部署到诸如移动设备、嵌入式设备和自动驾驶系统等轻量化系统中.基于此,提出了一种更好地平衡速度和精度的轻量级行人检测器(EPDNet)....     

基于深度神经网络的移动端人像分割

针对现有的人像分割算法大多忽略移动设备的硬件限制，盲目追求效果，以致无法满足移动端对于分割速度要求的问题，提出了一种可在移动设备上高效运行的人像分割网络。首先，基于编码器-解码器的轻量级U型架构来构建网络；其次，为了克服全卷积网络（FCN）受制于较小的感受域，无法充分捕获长距离信息的缺陷，引入期望最大化注意力块（EMAU）置于编码器之后、解码器之前；然后，在训练阶段添加多层边界辅助损失，有助于提高人物边界轮廓的准确度；最后，对模型进行量化和压缩。在Veer数据集上将所提网络与PortraitFCN+、ENet和BiSeNet等网络进行对比实验。实验结果表明，所提网络可以提高图像推理速度和分割效果，并能够以95.57%的准确率处理分辨率为224×224的RGB图像。     

基于深度神经网络的移动端人像分割

针对现有的人像分割算法大多忽略移动设备的硬件限制，盲目追求效果，以致无法满足移动端对于分割速度要求的问题，提出了一种可在移动设备上高效运行的人像分割网络。首先，基于编码器-解码器的轻量级U型架构来构建网络；其次，为了克服全卷积网络（FCN）受制于较小的感受域，无法充分捕获长距离信息的缺陷，引入期望最大化注意力块（EMAU）置于编码器之后、解码器之前；然后，在训练阶段添加多层边界辅助损失，有助于提高人物边界轮廓的准确度；最后，对模型进行量化和压缩。在Veer数据集上将所提网络与PortraitFCN+、ENet和BiSeNet等网络进行对比实验。实验结果表明，所提网络可以提高图像推理速度和分割效果，并能够以95.57%的准确率处理分辨率为224×224的RGB图像。     

可外包解密和成员撤销的身份基加密方案

针对可撤销成员的身份基加密（RIBE）方案中密钥更新效率较低,且解密的工作量较大,难以应用于轻量级设备的问题,提出了一个可外包解密和成员撤销的身份基加密方案（RIBE-OD）。首先,生成一个完全二叉树,为这棵树的每个节点指定一个一次多项式。然后,将基于指数逆模式构造的身份基加密（IBE）方案和完全子树方法相结合,利用该一次多项式计算所有用户的私钥和未撤销用户的更新密钥,撤销用户因不能获得与之匹配的更新密钥而失去解密能力。其次,利用外包解密技术修改密钥生成算法,增加密文转换算法,从而将大部分解密运算量安全外包给云服务器,轻量级设备仅需少量运算即可解密密文。最后,基于判定双线性Diffie-Hellman逆转（DBDHI）假设,证明了所提方案的安全性。与BGK方案相比,该方案的密钥更新效率提高了85.7%,轻量级设备的解密过程减少到一个椭圆曲线指数运算,非常适合于轻量级设备解密密文。     

Depth‐enhanced integral‐imaging 3D display using different optical path lengths by polarization devices or mirror barrier array

Abstract— Depth‐enhanced integral three‐dimensional (3D) imaging using different optical path lengths by using a polarization selective mirror pair or mirror barrier array is proposed. In the proposed approach, the enhancement of image depth is achieved by repositioning two types of elemental image planes, thus effectively two central depth planes are obtained. One of the two implementation methods makes use of the two‐arm structure that has different optical path lengths and polarization‐selective mirrors. The other utilizes the mirror barrier array. The primary advantage of the method with polarization devices is that we can observe 3D images that maintain some level of viewing resolution with a large depth difference without any mechanical moving part. The mirror barrier array has the advantage of the compact thickness. We demonstrated and verified our proposals experimentally.     

Designing novel proxy-based access control scheme for implantable medical devices

Implantable medical devices (IMDs) are small medical devices implanted within the human body, performing diagnostic, monitoring, and therapeutic functions. Modern IMDs are equipped with a radio transmitter and can communicate with a specialized external programmer device (i.e., IMD programmer) through the wireless channel. IMDs are extremely limited in computation power, storage and battery capacity, hence can only afford lightweight cryptographic operations. This makes IMDs vulnerable to adversarial attacks especially on the wireless interface. In this paper, we propose a novel proxy-based fine-grained access control scheme for IMDs, which can prolong the IMD’s lifetime by delegating the heavy cryptographic computations to a proxy device (e.g., smartphone). Additionally, we use the ciphertext-policy attribute-based encryption (CP-ABE) to enforce fine-grained access control so that only the qualified and/or authorized individuals can access the IMDs. The proposed scheme is implemented on real emulator devices. The experimental results show that the proposed scheme is lightweight and effective.     

The yoking-proof-based authentication protocol for cloud-assisted wearable devices

Along with the development of IoT applications, wearable devices are becoming popular for monitoring user data to provide intelligent service support. The wearable devices confront severe security issues compared with traditional short-range communications. Due to the limitations of computation capabilities and communication resources, it brings more challenges to design security solutions for the resource-constrained wearable devices in IoT applications. In this work, a yoking-proof-based authentication protocol (YPAP) is proposed for cloud-assisted wearable devices. In the YPAP, a physical unclonable function and lightweight cryptographic operators are jointly applied to realize mutual authentication between a smart phone and two wearable devices, and yoking-proofs are established for the cloud server to perform simultaneous verification. Meanwhile, Rubin logic-based security formal analysis is performed to prove that the YPAP has theoretical design correctness. It indicates that the proposed YPAP is flexible for lightweight wearable devices in IoT applications.     

改进ShuffleNet V2的轻量级农作物病害识别方法

针对目前有关深度学习的农作物病害识别方法中存在模型较为复杂,部署在计算资源有限的边缘设备和移动终端上适应性不强,实时准确识别作物病害较差的问题,提出一种改进ShuffleNet V2的轻量级农作物病害识别方法。以ShuffleNet V2单元为基础,引入ECA（efficient channel attention）注意力模块,使用H-Swish激活函数以便减少网络结构每个Stage模块中ShuffleNet V2单元使用个数,使用轻量化网络设计组件深度可分离卷积。在PlantVillage病害数据集上进行实验。结果表明,模型的参数量约为2.95×105,计算量为3.388×107（FLOPs）和6.674×107（MAdd）,病害识别平均准确率达到了99.24%,为农作物病害识别方法在移动终端等资源受限设备上部署应用提供参考。     

Formal apparatus for measurement of lightweight protocols

Lightweight protocols are an important topic in the area of computer communications. With the proliferation of security services not only ordinary communication protocols, but also cryptographic protocols, i.e. security services, have become a subject of research into possible appropriate lightweight solutions. At first glance it may seem surprising, but the evidence suggests that there is a permanent need for lightweight protocols. And this need is ever increasing, due to the gap between desktop (and other ordinary computing devices) and mobile wireless devices that have inherently limited resources. However, the notion of lightweight protocol has not been formally addressed in the literature, which is the purpose of this paper. A formal model that can be used to evaluate lightweight properties of protocols is presented and the appropriate metrics are introduced. Despite the fact that the model and the metrics target weak processing devices, they can be deployed for ordinary computing environments and may present a methodology for evaluation of lightweight cryptographic protocols in standardization processes.     

Three-dimensional histogram shifting for reversible data hiding

Histogram shifting is an important method of reversible data hiding. However, every pixel, difference, or prediction-error is respectively changed to hide a data bit in the traditional histogram shifting, which constrains the capacity-distortion embedding performance. An efficient three-dimensional histogram shifting is proposed for reversible data hiding in this paper. Take H.264 videos as covers to show this method. In a 4 × 4 quantized discrete cosine transform luminance block, which is not inferred by others, three alternating current coefficients are selected randomly as an embeddable group. According to the different values of the selected coefficient groups, they could be divided into different sets. Data could be hidden according to these sets. In the traditional histogram shifting, only one information bit could be hidden with at most one modification of one coefficient, whereas two data bits could be hidden at the same cost by using the proposed scheme. The superiority of the presented technique is verified through experiments.