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为了获取HL-2A等离子体的离子温度、旋转速度及其分布等重要参数,首次在HL-2A装置上开展了CXRS诊断。通过利用能有效探测微弱光的EMCCD和特殊设计的光学采集系统,获得了具有足够信噪比的诊断信号。实验得到的测量信号分析表明,设计是切实可行的。     

A wrapper‐based feature selection for improving performance of intrusion detection systems

Along with expansion in using of Internet and computer networks, the privacy, integrity, and access to digital resources have been faced with permanent risks. Due to the unpredictable behavior of network, the nonlinear nature of intrusion attempts, and the vast number of features in the problem environment, intrusion detection system (IDS) is regarded as the main problem in the security of computer networks. A feature selection technique helps to reduce complexity in terms of both the executive load and the storage by selecting the optimal subset of features. The purpose of this study is to identify important and key features in building an IDS. To improve the performance of IDS, this paper proposes an IDS that its features are optimally selected using a new hybrid method based on fruit fly algorithm (FFA) and ant lion optimizer (ALO) algorithm. The simulation results on the dataset KDD Cup99, NSL‐KDD, and UNSW‐NB15 have shown that the FFA–ALO has an acceptable performance according to the evaluation criteria such as accuracy and sensitivity than previous approaches.     

温室大棚环境监测及控制系统的设计

我国是农业种植大国,针对传统温室大棚人工成本高、管理效率低下的问题,本文设计了一种温室大棚环境监测及控制系统,实现了对温室大棚内环境的实时监测和远程管理。该系统以STM32L4为主控芯片,通过NB-IOT无线通信模块入网,设备对接华为OceanConnect物联网开发平台,管理人员通过登录平台实现对监测终端的远程管理。测试表明,该系统系统工作稳定、可靠性较强、性价比优势更为明显,对农作物的信息化种植提供了较好的参考。     

Adaptive Speech Streaming Based on Packet Loss Prediction Using Support Vector Machine for Software‐Based Multipoint Control Unit over IP Networks

An adaptive speech streaming method to improve the perceived speech quality of a software‐based multipoint control unit (SW‐based MCU) over IP networks is proposed. First, the proposed method predicts whether the speech packet to be transmitted is lost. To this end, the proposed method learns the pattern of packet losses in the IP network, and then predicts the loss of the packet to be transmitted over that IP network. The proposed method classifies the speech signal into different classes of silence, unvoiced, speech onset, or voiced frame. Based on the results of packet loss prediction and speech classification, the proposed method determines the proper amount and bitrate of redundant speech data (RSD) that are sent with primary speech data (PSD) in order to assist the speech decoder to restore the speech signals of lost packets. Specifically, when a packet is predicted to be lost, the amount and bitrate of the RSD must be increased through a reduction in the bitrate of the PSD. The effectiveness of the proposed method for learning the packet loss pattern and assigning a different speech coding rate is then demonstrated using a support vector machine and adaptive multirate‐narrowband, respectively. The results show that as compared with conventional methods that restore lost speech signals, the proposed method remarkably improves the perceived speech quality of an SW‐based MCU under various packet loss conditions in an IP network.     

探针体耐尔蓝(NB)与DNA结合反应研究

应用微相吸附-光谱修正（MPASC）新技术研究DNA与耐尔蓝（NB）探针分子间的相互作用,分析生物大分子内静电场的形成与Langmuri吸附的关联性,测定了结合产物结合比、平衡常数等。通过在pH=10.38介质中对DNA-NB反应的光谱分析,结果表明产物结合比NB：DNA-P=3：1、平衡常数K=3.33×10^5,摩尔吸收系数ε^660nm=4.81×10^3L/mol cm。样品分析表明DNA回收率95.6%-108%,相对标准偏差RSD=2.8%。     

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对EAST中性束反向注入过程中等离子体加热和电流驱动进行了实验研究,并采用了美国普林斯顿大学等离子体物理实验室开发的TRANSP程序对高功率中性束注入过程中能量热输运进行了分析.结果表明,中性束注入可有效提高本底等离子体温度,产生束驱动非感应电流,提高等离子体旋转以及有效改善等离子体约束.     

浅谈NB-IoT关键技术及应用

NB-IoT终端支持超低功耗、超大覆盖、超大连接。在广域网蜂窝数据网络下,也被称之为低功耗广域网;NB-IoT终端待机时间长、对网络连接要求较低。NB-IoT设备电池寿命长,最高可以延长使用10年,同时还能为室内提供全面的蜂窝数据连接覆盖系统。     

硒化壳聚糖对NB4细胞作用的实验研究

应用MTT法、AO/EB荧光染色法和NBT还原法观察硒化壳聚糖对NB4肿瘤细胞株生长的影响。结果发现,硒化壳聚糖可有效地抑制NB4细胞生长,并呈量效、时效关系。经100 mg/L及以上剂量硒化壳聚糖作用后的细胞可明显出现核固缩、碎裂等凋亡形态改变。而经100 mg/L以下剂量硒化壳聚糖作用后,细胞可出现诱导分化成熟的表现。     

Figure of merit for narrowband,wideband and multiband LNAs

In software defined radio, the same radio front end is used to accommodate different wireless standards operating in different frequency bands. The use of wideband or multiband low noise amplifiers (LNAs) is mandatory in such situations. There are several figures of merit (FoMs) proposed for narrowband LNAs. These FoMs are modified for wideband/multiband LNAs just by the inclusion of 3?dB bandwidth, and designers tend to use the one that favours their own design. In this article, a review of the existing FoMs for narrowband LNAs is presented. Based on this analysis, we propose two different FoMs for fair comparison of improvement in LNA parameters due to complementary metal oxide semiconductor (CMOS) technology advancement and circuit optimisation (irrespective of transistor technology), separately. The empirical technology scaling factor for gain, noise figure (NF), f _T and linearity is used to differentiate between these FoMs for different types of LNAs.     

移动用户行为模型的研究与应用

中国移动用户对通话质量的要求越来越高,通话区域也日益广泛和复杂。识别用户通话中的具体场景,建立有效的用户行为模型,进行针对性的网络优化,是挽留客户的重要手段。本文研究的内容,首先在Nb/Mc接口以镜像的方式采集信令和媒体,分析数据所包含的用户位置信息;然后运用统计的方法建立不同用户场景的行为模型;最后使用该模型对全网的移动用户进行场景分类,进行通话质量的分析。