Kinetics of emitted mass—A study with three dry powder inhaler devices

The purpose of this study was to understand the kinetics of emptying of micronised salbutamol sulphate (SS) and lactohale 300 (LH300) under varying air flow rates (30–180 L min⁻¹) from three dry powder inhaler devices, Rotahaler^® (RH), Monodose Inhaler^® (MI) and Handihaler^® (HH). Aerosol concentration vs. time profiles, determined through real-time laser diffraction particle sizing, demonstrated that the majority of the powder from RH was emitted within one second while a more prolonged aerosolisation was observed from MI and HH. Peak aerosol concentrations were achieved more rapidly from RH compared to MI for both SS and LH300. Calculated cumulative emitted mass (CCEM) vs. time profiles were obtained from the aerosol concentration vs. time profiles and the emitted mass and the rate of CCEM (k_CCEM), estimated from a modelling approach, increased with increasing air flow rates. The k_CCEMvs. air flow rate profiles of SS and LH300 were significantly different at high air flow rates. The k_CCEM was highest from RH and lowest from MI. Differences in k_CCEM between the devices were related to capsule aperture size while the differences between the materials were due to the powder bed structure. This approach provided an understanding of the rate at which powder mass emptied from dry powder inhaler devices and was proposed to be a powerful development tool for the future powder inhalers.     

Inhibitory effects of flavonoid glycosides isolated from the peel of Japanese persimmon (Diospyros kaki Fuyu) on antigen-stimulated degranulation in rat basophilic leukaemia RBL-2H3 cells

We found that two distinct flavonoid glycosides isolated from the peel of Japanese persimmon (Diospyros kaki Fuyu), isoquercitrin (Isq) and hyperin (Hyp), are capable of inhibiting antigen-stimulated degranulation in rat basophilic leukaemia RBL-2H3 cells. In order to elucidate the underlying mechanisms, we examined effects of Isq and Hyp on cellular responses induced by antigen stimulation. Treatment with both Isq and Hyp markedly inhibited antigen-stimulated elevation of intracellular free Ca²⁺ concentration and reactive oxygen species (ROS). Isq and Hyp did not affect NADPH oxidase (NOX) activity, but they possessed DPPH radical-scavenging activity similar to that of epigallocatechin gallate, a potent anti-oxidant, Finally, Isq and Hyp showed little or no effects on Ag-stimulated Syk activation or phosphorylation of signalling molecules. These results indicate that inhibition of antigen-stimulated degranulation by Isq and Hyp is mainly due to suppression of intracellular Ca²⁺ elevation, which is caused by direct scavenging of ROS that are generated by NOX. Our findings suggest that Isq and Hyp, isolated from the peel of persimmon, would be beneficial for alleviating symptoms of type I allergy.     

基于WLAN智能管道平台的精细化网络优化研究

提出了一种基于WLAN智能管道平台的网络优化手段,借助WLAN智能管道用户可识别、业务可区分能力,分析制定策略,应对WLAN网络规模持续增长可能导致的部分热点信道利用率恶化问题,从而改善用户感知以及提升网络容量。     

星载计算机软硬件协同验证技术的研究

在星载计算机LYRA的设计和验证过程中,采用System Verilog的DPI建立了完整的、低成本的、高效的SOC系统软硬件协同验证的系统仿真平台;利用这种技术使得可以在实际硬件可用前进行C/C++代码的开发和测试,同时又可以利用真实的软件对硬件进行验证;在早期软硬件可以公用测试平台进行并行开发,不仅大大减少软硬件开发的重复工作,加快了验证速度,还能对软硬件之间的边角情况进行完整的验证;验证方法已经成功的应用于星载计算机LYRA的开发中,取得了良好的效果。     

Comparison among emission and susceptibility reduction techniques for electromagnetic interference in digital integrated circuits

This paper presents a comparative study of susceptibility reduction techniques for electromagnetic interference (EMI) in digital integrated circuits (ICs). Both direct power injection (DPI) and very-fast transmission-line pulsing (VF-TLP) methods are used to inject interference into the substrate of a single test chip. This IC is built around six functionally identical cores, differing only by their EMI protection strategies (RC protection, isolated substrate, meshed power supply network) which were initially designed for low emission design rules. The ranking of three of these cores in terms of electromagnetic immunity is then compared with the one of their radiated emission, thanks to near-field scanning (NFS) measurements. This leads to the establishing of design guidelines for low EMI in digital ICs.     

网络背景流量的分类与识别研究综述

互联网流量分类是识别网络应用和分类相应流量的过程,这被认为是现代网络管理和安全系统中最基本的功能。与应用相关的流量分类是网络安全的基础技术。传统的流量分类方法包括基于端口的预测方法和基于有效载荷的深度检测方法。在目前的网络环境下,传统的方法存在一些实际问题,如动态端口和加密应用,因此采用基于流量统计特征的机器学习（ML）技术来进行流量分类识别。机器学习可以利用提供的流量数据进行集中自动搜索,并描述有用的结构模式,这有助于智能地进行流量分类。起初使用朴素贝叶斯方法进行网络流量分类的识别和分类,对特定流量进行实验时,表现较好,准确度可达90%以上,但对点对点传输网络流量（P2P）等流量识别准确度仅能达到50%左右。然后有使用支持向量机（SVM）和神经网络（NN）等方法,神经网络方法使整体网络流量的分类准确度能达到80%以上。多项研究结果表明,对于多种机器学习方法的使用和后续的改进,很好地提高了流量分类的准确性。     

一种基于DPI的OTT盒子智能分析方案

互联网上OTT终端规模已达到亿级的规模,这对公司的"和TV"业务带来了巨大的竞争影响。另一方面,如此庞大的业务需求对宽带质量的要求更高,OTT盒子使用的感知体验直接影响用户家宽满意度评价。基于此,文章特提出一种基于DPI的OTT盒子智能分析方案,该方案采用统一DPI自定义识别库加载,新增单据的终端类型字段,实现终端的识别;另一方面引入智能图片识别技术,实现盒子资源和质量的探测。     

基于VP技术的星载智能计算机虚拟原型机的构建

作为新技术和新生产力水平基础上涌现出来的产物,以全新设计理念研制的现代小卫星相较于传统大卫星在功能密度上有了显著提升,得到了广泛的应用。针对目前现代小卫星技术面临的设计复杂度提高和研发周期缩短的双重压力,提出了一种基于虚拟原型（Virtual Platform, VP）技术来构建星载智能计算机的虚拟原型机的设计,利用SystemVerilog的直接编程接口（Direct Programming Interface, DPI）技术在仿真验证平台上对C语言的调用,实现不同硬件平台间的通信,模拟星载计算机在轨运行的数据流向。该设计能缩短卫星的研发周期,降低卫星研制的成本。通过工程实例中虚拟原型机中的构建流程展示,结果证明,基于VP技术构建的虚拟原型机能够模拟星载计算机的部分工作流程,实现星载计算机的功能仿真,满足了商业小卫星快速迭代的研发需求,为小卫星的研制提供新的思路。     

A new trust-based mechanism for detecting intrusions in MANET

Providing security to Mobile Ad-hoc Networks (MANET) is a challenging and demanding task. It is important to secure the network against intrusions in MANET for assuring the development of services. For this purpose, some intrusion-detection systems (IDSs) have been developed in traditional works. However, these have some drawbacks, such as that there is no assurance for public key authentication, certificate validation between two nodes is not possible, and they require a large amount of time for processing. To overcome all these issues, a Trust-Based Authentication Routing with Bio-Inspired Intrusion Detection System (TRAB-IDS) is developed in this article. The main aim of this article is to provide security to the network against harmful intrusions. Here, the trust and deep packet inspection (DPI) concepts are integrated for improving the security. Moreover, the certificate authority generates a public and private key pair for initiating the route agent and authenticating the neighboring nodes. Based on the trust of the node, the packet is forwarded to the intermediate node by calculating a bogus key. Then, the DPI is initiated for extracting the packet features and the similarity between the features is estimated. If the packet is matched with the attacker, an error report will be forwarded to the certificate authority; otherwise, the packet will be forwarded to the other node. The experimental results evaluate the performance of the proposed TRAB-IDS in terms of delivery ratio, delay, security cost, and misdetection ratio.     

基于HASH-TCAM算法的高速模式匹配研究*

针对基于硬件的模式匹配算法处理长模式串时吞吐率不高的问题,提出了基于将哈希压缩与TCAM查表相结合的算法——HASH-TCAM算法。通过哈希算法将待匹配的关键字预处理,减少其长度,解决了40 Gbps线速下的长模式串匹配问题,并通过40 Gbps测试仪验证了该算法的可行性。分析表明,该算法在查询的固定关键字长度为72 Byte,模式集数目为5000,哈希压缩后地址的编码宽度为46 bit时,模式识别模块以牺牲冲突的代价实现了51.2 Gbps的吞吐率,可以满足40 Gbps链路中DPI算法的逐包线速的需求