WPM在TD四期无线网络参数管理中的重点应用

本文首先介绍了无线网络参数管理软件WPM的架构及主要模块,同时结合项目组的实际技术支持经验,阐述了WPM 2.0在TD-SCDMA四期建设中的重点应用,主要包括WPM在场景管理、报告生成和智能天线权值管理,并介绍了无线参数工单派发相关功能。     

网络测量方法和关键技术

网络性能测量和评价是从事网络理论研究、网络管理和网络工程开发的重要手段。首先,简要回顾了网络测量的发展历程。然后,介绍了IP网络测量的概念并归纳了各种测量方法。接下来,详细论述了网络测量的若干关键技术,包括网络性能测量、网络流量测量和网络推测技术等。最后,对论文进行了小结。     

在PCB中埋置有源元件

摘要文章概述了埋置有源元件的重要意义和主要埋嵌方法。它较详细地评述了三种埋嵌有源元件方法——“先”埋嵌有源元件、“中间”埋嵌有源元件和“最后”埋嵌有源元件,而“最后”埋嵌有源元件是较好的方法。文章提供了“最后”埋置有源元件的样品与效果。     

一种基于基波磁通补偿的改进型有源滤波器

提出了一种基于基波磁通补偿的改进型串联混合型有源滤波器,此滤波器具有滤波和单位功率因数校正两种功能。详细分析了其工作原理并进行了仿真实验,仿真结果表明此滤波器具有较好的滤波效果,能进行单位功率因数校正,并且在负载突变时有很快的响应速度,大约在两个基波周期之内就达到稳态。     

新型电控可重构天线阵全向单元设计

该文提出了一种性能良好的新型方向图可重构天线阵全向印刷单元天线。该天线由两对半波振子背靠背印刷在介质板上构成,结构简单紧凑。相对带宽达50%(VSWR<2),在工作频带内,增益6.44 dBi,不圆度小于2.0 dB。文中给出了仿真设计结果和实测的电参数数据,两者有较好地一致性。本天线适用于WiMax(802.16)终端及WLAN基站或中继站天线。     

Asymmetric Semi‐Supervised Boosting Scheme for Interactive Image Retrieval

Support vector machine (SVM) active learning plays a key role in the interactive content‐based image retrieval (CBIR) community. However, the regular SVM active learning is challenged by what we call “the small example problem” and “the asymmetric distribution problem.” This paper attempts to integrate the merits of semi‐supervised learning, ensemble learning, and active learning into the interactive CBIR. Concretely, unlabeled images are exploited to facilitate boosting by helping augment the diversity among base SVM classifiers, and then the learned ensemble model is used to identify the most informative images for active learning. In particular, a bias‐weighting mechanism is developed to guide the ensemble model to pay more attention on positive images than negative images. Experiments on 5000 Corel images show that the proposed method yields better retrieval performance by an amount of 0.16 in mean average precision compared to regular SVM active learning, which is more effective than some existing improved variants of SVM active learning.     

Novel Shorted Meander‐Line USB Dongle Antenna with a Compact Ground Plane

This letter presents the design of a novel multiband USB dongle antenna with a compact ground plane. The radiating patch is composed of a modified meander‐line monopole and a shorted loop to generate a dual‐broadband resonance. The proposed antenna supports WiBro, Bluetooth, WLAN, WiMAX, and S‐DMB services. The total dimensions of the fabricated antenna are 10 mm × 45 mm × 1 mm, the most compact size among multiband USB dongle antennas reported to date. The measured 10 dB reflection loss bandwidths are 20.8% (2.24 GHz to 2.76 GHz) and 20.2% (4.86 GHz to 5.95 GHz). The measured peak gain is 2.97 dBi, and efficiency is higher than 58%. In addition, the radiation pattern approximates an omnidirectional pattern.     

Joint Channel Coding Based on Principal Component Analysis

This paper proposes a new joint channel coding algorithm based on principal component analysis. A conventional joint channel coder using passive downmixing undergoes a reduction of both the primary‐to‐ambient energy ratio (PAR) of the downmix signal and the panning gain ratio of the primary source. The proposed system preserves the PAR of the downmix signal by using active downmixing which reflects spatial characteristic. The proposed system also improves the accuracy of the panning gain ratio estimation. Computer simulations and subjective listening tests verify the performance of the proposed system.     

Design of an Internal Antenna with Near‐Omnidirectional H‐Plane Radiation Pattern over Ultra‐wide Bandwidth

In this paper, an ultra‐wideband internal antenna for use in mobile applications is proposed. The proposed antenna has symmetrical bi‐arm structures printed on the top and bottom of the substrate, and it occupies a compact area of 10 mm × 10 mm × 1 mm. The designed antenna has an impedance bandwidth from 3 GHz to 12 GHz and near omnidirectional radiation patterns over the frequency band of interest. The group delay between two antennas fabricated using the proposed design is less than 0.8 ns, and the maximum gain variation is about 3.16 dB.     

并联型有源电力滤波器直流侧电压柔性控制策略

针对并联型有源电力滤波器的直流侧电压控制特点,提出了一种对直流侧电压进行柔性控制的并联型有源电力滤波器控制策略。该策略中,在直流侧电压控制部分引入反馈低通滤波器,削弱直流侧固有谐波对输出电流控制的影响;在电流控制的输出部分通过增加直流侧电压前馈系数,抵制在变换桥中可能引入的直流侧电压谐波影响。仿真结果表明直流侧电压柔性控制策略能够降低APF系统补偿后的电源电流总谐波畸变率,从而改善并联型有源电力滤波器的谐波补偿性能。