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New Parallel Interference Cancellation for Convolutionally Coded CDMA Systems

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Wuhan University Journal of Natural Sciences 2004年第1期9卷 78-82页

作者： XuGuo-xiong GanLiang-cai huangtian-xi ＼ SchoolofElectronicInformation.WuhanUniversity Wuhan430072HubeiChina

Based on BCJR algorithm proposed by Bahlet al and linear soft decision feedback, a reduced-complexity parallel interference cancellation (simplified PIC) for convolutionally coded DS CDMA systems is proposed. By computer simulation, we compare the simplified PIC with the exact PIC. It shows that the simplified PIC can achieve the performance close to the exact PIC if the mean values of coded symbols are linearly computed in terms of the sum of initiala prior log-likelihood rate (LLR) and updateda prior LLR, while a significant performance loss will occur if the mean values of coded symbols are linearly computed in terms of the updateda prior LLR only. Meanwhile, we also compare the simplified PIC with MF receiver and conventional PICs. The simulation results show that the simplified PIC dominantly outperforms the MF receiver and conventional PICs, at signal-noise rate (SNR) of 7 dB, for example, the bit error rate is about 10?4 for the simplified PIC, which is far below that of matched-filter receiver and conventional PIC. Key words convolutionally coded CDMA - parallel interference cancellation - BCJR CLC number TN 914 Foundation item: Supported by the National Natural Science Foundation of China (69772015)Biography: Xu Guo-xiong (1967-), male, Ph. D candidate, research direction: wireless communication.

关键词： convolutionally coded CDMA parallel interference cancellation BCJR

New Parallel Interference Cancellation Scheme for DS/CDMA Systems

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Wuhan University Journal of Natural Sciences 2004年第1期9卷 73-77页

作者： XuGuo-xiong GanLiang-cai huangtian-xi SchoolofElectronicInformation WuhanUniversityWuhan430072HubeiChina

This paper proposes a new multi-stage parallel interference cancellation scheme by modifying the conventional multi-stage parallel interference canceller (PIC). At each stage, it first converts the interference-cancelled outputs from previous stage into thea prior information, in terms of which the bit mean values are computed and the multi-access interference (MAI) for each user is evaluated, and then an interference cancellation is performed to obtain further interference suppression. To reduce the implementation complexity, we give an approximation expression for bit mean value. The performance over AWGN channel is analyzed and compared to the conventional PIC. The user numberK=7 and spreading factorN=13 are chosen as simulation parameters. The computer simulation results show that the proposed PIC has better performance than the conventional PIC both with 2 interference cancellation (IC) stages, at bit error rate of 10?3, for example, about 3 dB performance gain is obtained by using the proposed PIC. It is also shown that our proposed PIC with 1-stage is superior to the conventional PIC with 2-stage in performance, which is of practical value because PIC with fewer stages can bring about shorter processing delay. Key words CDMA - parallel interference cancellation - multi-access interference CLC number TN 914 Foundation item: Supported by the National Natural Science Foundation of China (69772015)Biography: Xu Guo-xiong (1967-), male, Ph. D candidate, research direction: wireless communication.

关键词： CDMA parallel interference cancellation multi-access interference

RED-DTB: A Dual Token Bucket Based Queue Management Algorithm

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Wuhan University Journal of Natural Sciences 2003年第2A期8卷 388-392页

作者： YinJian-hua CaoYang LingJun huangtian-xi SchoolofElectronicInformation WuhanUniversityWuhan430072HubeiChina StateKeyLaboratoryofSoftwareEngineering WuhanUniversityWuhan430072HubeiChina

Improving the Quality of Service (QoS) of Internet traffic is widely recognized as a critical issue for the next-generation networks. In this paper, we present a new algorithm for the active queue management, namely RED-DTB. This buffer control technique is used to enforce approximate fairness among a large number of concurrent Internet flows. Like RED (Random Early Detection) algorithm, the RED-DTB mechanism can be deployed to actively respond to the gateway congestion, keep the gateway in a healthy state, and protect the fragile flows from being stolen bandwidth by greedy ones. The algorithm is based on the so-called Dual Token Bucket (DTB) pattern. That is, on the one hand, every flow is rate-limited by its own token bucket, to ensure that it can not consume more than its fair share of bandwidth; On the other hand, to make some compensations to less aggressive flows, such as connections with larger round trip time or smaller sending window, and to gain a relatively higher system utilization coefficient, all flows, depending on their individual behavior, may have a chance to fetch tokens from the public token bucket when they run out of their own share of tokens. The algorithm is analyzed and evaluated by simulations, and is proved to be effective in protecting the gateway buffer and controlling the fair allocation of bandwidth among flows.

关键词： Key words congestion control active queue management Dual Token Bucket fair bandwidth allocation network simulation

Photonic Bandgap Properties of One-Dimensional Photonic Crystal Consisting of Complex Artificial Media

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Wuhan University Journal of Natural Sciences 2005年第3期10卷 534-538页

作者： ZHANGYuan-nong XUGuo-xiong ZHAOZheng-yu huangtian-xi SchoolofElectronicInformation WuhanUniversityWuhan430072HubeiChina SchoolofElectronicInformation ZhongyuanUniversityofTechnologyZhengzhou450007HenanChina

Propagation of electromagnetic waves in one-dimensional (1-D) stratifiedchiral structures is described by the 4X4 transfer-matrix method. The photonic bandgap (PBG)properties in 1-D periodical chiral media are investigated. The relation between PBGand chiralityadmittance has been analyzed. Under proper operating parameters, quite perfect multichannelfiltering properties can be obtained with the periodic structure. The photonic bandgap properties ofone-dimensional layered periodical structures that include of double negative (DNG) medium,so-called backward-wave (BW) medium are investigated. The simulation results show that the width ofthe PBG in the structure composed of chiral medium and BW medium is larger then that composed ofchiral medium and usual medium. Our analysis has shown that the usage of the negative material makesit possible to dramatically widen the band gap of one-dimensional photonic crystal.

关键词： photonic bandgap transfer-matrix chiral medium negative refraction medium

Research on Digital Watermark Using Pre-Processing Technology

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Wuhan University Journal of Natural Sciences 2003年第03A期8卷 842-846页

作者： FluGuo-bao NiuHui-fang YangRui SunHong ShiHong-ling huangtian-xi SchoolofElectronicInformation WuhanUniversityWuhan430072HubeiChina MathematicsDepartment LuoyangTeacherCollegeLuoyang471022HenanChina

We have realized a watermark embedding system based on audio perceptual masking and brought forward a watermark detection system using pre\|processing technology. We can detect watermark from watermarked audio without original audio by using this method. The results have indicated that this embedding and detecting method is robust, on the premise of not affecting the hearing quality, it can resist those attacks such as MPEG compressing, filtering and adding white noise.

关键词： digital watermark audio perceptual masking DFT(Discrete Fourier Transform) RLS adaptive filter

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甜玉米新品种双色1424的选育

中国蔬菜 2021年第4期 101-103页

作者：王莹王晓玲席晓飞乔智辉王海旭陈辅志张正洁甘肃省酒泉市农业科学研究院甘肃酒泉735000 甘肃省酒泉市金辉农业开发有限公司甘肃酒泉735000 甘肃省酒泉市肃州区种子管理站甘肃酒泉735000

双色1424是以自交系黄甜3148为母本,以自交系白甜2110为父本配制而成的鲜食甜玉米一代杂种。生育期90 d(天)左右,株型半紧凑,株高209.5 cm,穗位高77.5 cm;果穗筒型,穗长21.0 cm,穗粗5.1 cm,穗行数15.3行,行粒数37.3粒,籽粒黄白相间,可... 详细信息

双色1424是以自交系黄甜3148为母本,以自交系白甜2110为父本配制而成的鲜食甜玉米一代杂种。生育期90 d(天)左右,株型半紧凑,株高209.5 cm,穗位高77.5 cm;果穗筒型,穗长21.0 cm,穗粗5.1 cm,穗行数15.3行,行粒数37.3粒,籽粒黄白相间,可溶性糖含量10.0%,支链淀粉占总淀粉含量的98.5%;中抗瘤黑粉病,每667 m^(2)鲜穗产量960 kg左右,适宜甘肃省河西地区(酒泉、张掖、武威)、中东部地区(兰州、白银)及相似生态区域种植。

关键词：甜玉米双色1424 一代杂种

甲硝唑联合克林霉素对母牛细菌性阴道炎的疗效观察

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中国牛业科学 2022年第4期48卷 25-29页

作者：吴宽林严业广刘家力张玉西广西贺州市八步区桂岭镇农业农村服务中心广西贺州542806 广西贺州市八步区南乡镇农业农村服务中心广西贺州542805 广西贺州市平桂区黄田镇农业农村服务中心广西贺州542807 广西贺州市八步区畜牧饲料与草地监理站广西贺州542800

[目的]探讨甲硝唑联合克林霉素治疗母牛细菌性阴道炎的临床效果。[方法]将确诊患有细菌性阴道炎的病牛25头,分为3组。Ⅰ组为观察组,患病母牛11头,用甲硝唑和克林霉素治疗;Ⅱ组为对照组1,患病母牛6头,用甲硝唑治疗;Ⅲ组为对照组2,患病母... 详细信息

[目的]探讨甲硝唑联合克林霉素治疗母牛细菌性阴道炎的临床效果。[方法]将确诊患有细菌性阴道炎的病牛25头,分为3组。Ⅰ组为观察组,患病母牛11头,用甲硝唑和克林霉素治疗;Ⅱ组为对照组1,患病母牛6头,用甲硝唑治疗;Ⅲ组为对照组2,患病母牛8头,用克林霉素治疗。甲硝唑注射液,5~6 g/头,24 h/次,连用5 d,静脉滴注;克林霉素,1.5~2 g/头,24 h/次,连用5 d,静脉滴注。治疗1个疗程后,对治愈母牛进行发情观察和人工授精配种。[结果]①观察组临床治疗有效率为90.91%,显著高于对照组1(80.33%)和对照组2(75.00%)(P<0.05);②观察组平均治疗效果为72.25%,显著高于对照组1(64.92%)和对照组2(57.89%)(P<0.05);③观察组、对照组1、对照组2和健康对照组牛发情率分别为81.82%,83.33%,75.00%和87.50%,观察组、对照组1和健康对照组显著优于对照组2,观察组、对照组1和健康对照组无显著差异;配种受胎率分别为72.72%,66.67%,62.50%和75.00%,观察组、健康对照组显著优于对照组1和对照组2(P<0.05);产活犊率分别为100%,75%,80%和100%,观察组、健康对照组显著优于对照组1和对照组2(P<0.05)。[结论]甲硝唑联合克林霉素治疗母牛细菌性阴道炎疗效显著,药物安全性高,不影响母猪的繁殖性能,具有临床推广价值;甲硝唑、克林霉素次之。

关键词：甲硝唑克林霉素细菌性阴道炎疗效观察

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