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移动图像通信系统卷积码的位交织方案性能研究
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作者 袁东风 王承祥 姚旗 《山东大学学报(自然科学版)》 CSCD 2000年第3期297-304,共8页
采用 (2 ,1 ,3 )卷积码结合一种新的交织方案 :位交织方案作为抗干扰措施 ,模拟并讨论了标准灰度图像的数据在相同调制方式、不同车速的移动衰落信道中的抗干扰问题 ,且与周期交织方案的结果做了比较 .模拟结果表明 :卷积码更适合于快... 采用 (2 ,1 ,3 )卷积码结合一种新的交织方案 :位交织方案作为抗干扰措施 ,模拟并讨论了标准灰度图像的数据在相同调制方式、不同车速的移动衰落信道中的抗干扰问题 ,且与周期交织方案的结果做了比较 .模拟结果表明 :卷积码更适合于快车速环境中图像数据的传输 .周期交织方案不适合于卷积码 ,而采用位交织方案的 (2 ,1 ,3 )卷积码可明显改善图像质量 ,大大提高了快衰落移动信道环境中图像通信系统的可靠性 . 展开更多
关键词 移动衰落信道 图像通信 卷积码 位交织
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基于多级码编码正交频分复用的差分幅度相位调制 被引量:1
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作者 赵光玲 束锋 吴乐南 《通信学报》 EI CSCD 北大核心 2003年第3期64-69,共6页
数字调幅广播(DAMB)需要高速的数据传输率,为此本文提出一种具有高带宽效率的编码调制方案。采用16差分幅度相位(16DAPSK)加正交频分复用(OFDM)调制,采用多级码(MLC)作为纠错编码,其分量码为标准卷积码及其删除型卷积码,系统具有高的带... 数字调幅广播(DAMB)需要高速的数据传输率,为此本文提出一种具有高带宽效率的编码调制方案。采用16差分幅度相位(16DAPSK)加正交频分复用(OFDM)调制,采用多级码(MLC)作为纠错编码,其分量码为标准卷积码及其删除型卷积码,系统具有高的带宽利用率,抗多径传输,接收端可以并行解码,以减小通常逐层解码所带来的大的时延和误差传播,并且由于差分调制的引入,接收端可以采用非相关检测,且毋须均衡器,简化了接收机的设计,本文还比较了短波信道中,采用时域差分和频域差分的效果,并得出了相应的结论。 展开更多
关键词 多级码 差分幅度调制 正交频分复用 TURBO码 位交织 网格码 数字调幅广播
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迭代译码的LDPC-BICM方案在中短波信道中性能分析 被引量:2
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作者 顾品标 吴乐南 《信号处理》 CSCD 北大核心 2014年第1期30-36,共7页
低密度奇偶校验码(LDPC)具有码字构造灵活、译码复杂度低、性能优异以及频谱利用率高等特点。本文简介了LDPC码及位交织编码调制迭代译码(BICM-ID)方案,提出了将LDPC码作为分量码的BICM-ID方案用于多电平正交幅度调制(M-QAM)的OFDM通信... 低密度奇偶校验码(LDPC)具有码字构造灵活、译码复杂度低、性能优异以及频谱利用率高等特点。本文简介了LDPC码及位交织编码调制迭代译码(BICM-ID)方案,提出了将LDPC码作为分量码的BICM-ID方案用于多电平正交幅度调制(M-QAM)的OFDM通信系统中,并给出了多电平正交幅度调制的对数似然比置信传播(LLR-BP)译码算法。最后,根据数字广播信道的特点,比较了基于LDPC-BICM-ID方案与DRM标准中码率匹配的删除卷积码多级编码方案(RCPC/MLC)的OFDM系统在中、短波广播信道中的误码率性能。仿真结果表明,本文所提出的方案的性能优于RCPC/MLC方案。 展开更多
关键词 正交频分复用 低密度奇偶校验码 位交织编码调制迭代译码 多电平一正交幅度调制 数字广播
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瑞利信道下基于Turbo-BICM-ID的DFT-S-OFDM性能研究 被引量:2
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作者 高红山 高凡琪 《无线电工程》 2017年第9期38-43,共6页
为了提升DFT-S-OFDM系统在瑞利信道下的传输性能,采用位交织编码调制迭代译码方案(BICM-ID)、旋转映射(R-QAM)和Turbo码等技术,设计了基于Turbo-BICM-ID的DFT-S-OFDM系统。给出了系统原理框图,对编码调制系统的解调译码迭代算法进行了推... 为了提升DFT-S-OFDM系统在瑞利信道下的传输性能,采用位交织编码调制迭代译码方案(BICM-ID)、旋转映射(R-QAM)和Turbo码等技术,设计了基于Turbo-BICM-ID的DFT-S-OFDM系统。给出了系统原理框图,对编码调制系统的解调译码迭代算法进行了推导,对系统进行了Matlab仿真验证。仿真结果表明,与传统的卷积码设计方案相比,该设计方案在误码率为10-5时,可以获得5.7 d B的增益改善,同时可以获得更低的错误平层,有效地改善了DFT-S-OFDM系统在瑞利信道下的性能。 展开更多
关键词 DFT-S-OFDM 位交织编码调制迭代译码 旋转映射 TURBO码
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移动衰落信道中BICM方案及其与BCM的性能比较
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作者 宋晓飞 袁东风 《山东大学学报(理学版)》 CAS CSCD 北大核心 2004年第1期76-78,83,共4页
用计算机仿真的方法分析了位交织编码调制 (BitInterleavedCodedModulation ,BICM)的关键技术及其与分组编码调制方案的性能比较 .
关键词 移动衰落信道 位交织编码调制 纠错抗干扰
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OFDM系统中新的编码调制算法研究
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作者 余慧敏 王玲 《计算机仿真》 CSCD 2006年第10期312-314,320,共4页
传统位交织编码调制(BICM)算法由于受信道准静止性和频率选择特性的制约,应用范围受限。该文将基于固定门限的子带自适应编码调制方法(AMC)和构造在双正交序列集上的比特交织编码调制方案结合,应用于正交频分复用(OFDM)系统中,提出一种... 传统位交织编码调制(BICM)算法由于受信道准静止性和频率选择特性的制约,应用范围受限。该文将基于固定门限的子带自适应编码调制方法(AMC)和构造在双正交序列集上的比特交织编码调制方案结合,应用于正交频分复用(OFDM)系统中,提出一种AMC—BIC—OFDM级联系统,通过选择子带最低SNR高于门限且吞吐最大的参数作为该子带的调制参数,提高系统频谱利用率,弥补传统BICM由频率选择相关性和信道准静止性带来的编码分集损失,扩展BICM算法的应用。文章在分析系统成对错误概率的基础上,对级联系统的平均信息速率进行了仿真。结果证明,该文级联系统取得高出一般位交织编码调制系统2—6分贝的性能增益。 展开更多
关键词 自适应编码调制 位交织编码调制 正交频分复用
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一种新型亚阈值SRAM单元设计
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作者 孔得斌 乔树山 袁甲 《航空科学技术》 2020年第2期60-65,共6页
降低电源电压能够大幅降低芯片的功耗,进而减小航空电子设备的能量消耗,为使静态随机存储器能够工作在低电压下,面向亚阈值区设计了一种新型的12T存储单元。该单元通过两个堆叠的访问管完成数据的写入操作,通过一个访问管完成读操作,这... 降低电源电压能够大幅降低芯片的功耗,进而减小航空电子设备的能量消耗,为使静态随机存储器能够工作在低电压下,面向亚阈值区设计了一种新型的12T存储单元。该单元通过两个堆叠的访问管完成数据的写入操作,通过一个访问管完成读操作,这样能够消除半选单元的干扰问题并使单元适用于位交织结构。并且单元的读访问路径被专用管子从真实存储节点隔离,在增加读稳定性的同时保证了充足的电压感知裕量。应用多阈值设计技术提升单元的写能力并降低漏电功耗。仿真结果表明,在0.4V电压下提出的新型12T单元相较于传统6T单元读噪声容限提升80%、写能力提升60%,相较于10T单元电压感知裕量和访问速度都获得了提升。该12T单元更适用于低压操作。 展开更多
关键词 低功耗 SRAM 新单元 位交织 线漏电补偿 多阈值
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丽音技术(三)
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作者 胡瑞海 《今日电子》 1995年第3期100-103,共4页
(四)位交织、扰码及数字调制 1.位交织及处理技术 (1)位交织 所谓“位交织”就是把原来的数据的码序打乱,然后再按一定的规则重新排列。作用是为了减小出现连续多位误码时对所传送数据造成的不良影响,为此对704比特的信号数据“位交织... (四)位交织、扰码及数字调制 1.位交织及处理技术 (1)位交织 所谓“位交织”就是把原来的数据的码序打乱,然后再按一定的规则重新排列。作用是为了减小出现连续多位误码时对所传送数据造成的不良影响,为此对704比特的信号数据“位交织”处理。 在NICSM系统中。 展开更多
关键词 丽音 位交织处理 扰码 数字调制
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Clinicopathologic significance of HER-2/neu protein expression and gene amplification in gastric carcinoma 被引量:35
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作者 Shi-Yan Yan Ying Hu +5 位作者 Jian-Gao Fan Guo-Quan Tao Yong-Ming Lu Xu Cai Bao-Hua Yu Yi-Qun Du 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第11期1501-1506,共6页
AIM:To study the HER-2/neu protein expression and gene amplification in gastric carcinoma and their relation.METHODS:One hundred and forty-five formalin-fixed and paraffin-embedded tumor tissue samples from Chinese ga... AIM:To study the HER-2/neu protein expression and gene amplification in gastric carcinoma and their relation.METHODS:One hundred and forty-five formalin-fixed and paraffin-embedded tumor tissue samples from Chinese gastric carcinoma patients were studied with immunohistochemistry(IHC)and fluorescence in situ hybridization(FISH)methods.Clinicopathologic data about all patients were collected.RESULTS:The levels of HER-2 3+,HER-2 2+and HER21+were measurable in 6.9%,8.3%and 17.2%of the samples,respectively.No HER-2 was stained in 67.6% of the samples.FISH showed that HER-2 gene was amplified in 18 samples,10 HER-2 3+samples,5 HER-2 2+samples,and 3 HER-2 1+samples with IHC staining.HER-2 status was not correlated with the sex and age of patients,and tumor size,location or differentiation,but with the depth of invasion,TNM stage,lymph node and distant metastasis as well as histopathological classification of gastric cancer(P<0.05).CONCLUSION:All samples with IHC as HER-2 expression should be analyzed with FISH.Detection of HER-2 gene amplification can assess the malignant biological behaviors and prognosis of gastric cancer. 展开更多
关键词 Gastric carcinoma HER-2 Clinocopathologic significance IMMUNOHISTOCHEMISTRY Fluorescence in situ hybridization
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HER-2 expression after neoadjuvant chemotherapy of the breast cancers 被引量:1
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作者 Yaojun Feng Xinhong Wu Cuiping Pan Juan Xu Wei Zhong Jun Shao Biao Ma 《The Chinese-German Journal of Clinical Oncology》 CAS 2011年第8期476-479,共4页
Objective:The aim of this study was to study changes of HER-2 expression after neoadjuvant chemotherapy in the breast cancer cases.Methods:One hundred and thirty-seven female patients with primary breast cancers,who r... Objective:The aim of this study was to study changes of HER-2 expression after neoadjuvant chemotherapy in the breast cancer cases.Methods:One hundred and thirty-seven female patients with primary breast cancers,who received neoadjuvant chemotherapy,underwent core needle puncture and Mammotome biopsy before chemotherapy,and the biopsy results were used as the basis of histological diagnosis,fluorescence in situ hybridization (FISH) was performed to test HER2 status of tumor tissues before and after chemotherapy.All patients underwent FEC,TE,or AC neoadjuvant chemotherapy of 2-6 cycles before surgery.Results:Twenty-two patients were positive according to FISH test among 137 preoperative patients,8 patients achieved pathological complete remission after chemotherapy (three HER-2 positive patients and five negative patients),91 patients achieved partial remission,24 patients were stable,and 14 cases were invalid.Twenty-two patients were positive according to FISH test (8 patients with pathological complete remission did not undergo test),and positive patients still expressed positively after chemotherapy before neoadjuvant chemotherapy.Three negative patients were converted to be positive,and changes before and after chemotherapy had no statistical difference (P>0.05).Conclusion:Neoadjuvant chemotherapy makes no influence on patients with HER-2 positive expression,while patients with negative expression can be converted to be positive,but without significant difference. 展开更多
关键词 breast cancer HER-2 gene neoadjuvant chemotherapy fluorescence in situ hybridization (FISH)
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Expression and localization of a novel phosducin-like protein from amphioxus Branchiostoma belcheri
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作者 萨仁高娃 赵永刚 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第2期324-330,共7页
A full length amphioxus cDNA, encoding a novel phosducin-like protein (Amphi-PhLP), was identified for the first time from the gut cDNA library of Branchiostoma belcheri. It is comprised of 1 550 bp and an open read... A full length amphioxus cDNA, encoding a novel phosducin-like protein (Amphi-PhLP), was identified for the first time from the gut cDNA library of Branchiostoma belcheri. It is comprised of 1 550 bp and an open reading frame (ORF) of 241 amino acids, with a predicted molecular mass of approximately 28 kDa. In situ hybridization histochemistry revealed a tissue-specific expression pattern of Amphi-PhLP with the high levels in the ovary, and at a lower level in the hind grit and testis, hepatic caecum, gill, endostyle, and epipbaryngeal groove, while it was absent in the muscle, neural tube and notochord. In the Chinese Hamster Ovary (CHO) cells transfected with the expression plasmid pEGFP-NI/Amphi-PhLP, the fusion protein was targeted in the cytoplasm of CHO cells, suggesting that Amphi-PhLP is a cytosolic protein. This work may provide a framework for further understanding of the physiological function of Amphi-PhLP in B. belcheri. 展开更多
关键词 amphioxus B. belcheri Amphi-PhLP northern blotting in situ hybridization cellularlocalization
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Study on the protein expression and amplification of HER2 gene in gastric cancer
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作者 Sunan Wang Yingying Li +4 位作者 Zhengshun Xu Wenzhao Zhao Tian Yun Wuling Zhu Yangkun Wang 《The Chinese-German Journal of Clinical Oncology》 CAS 2014年第6期267-272,共6页
Objective: The aim of the study was to investigate the human epidermal growth factor receptor 2(HER2) gene amplification and protein expression and interpretation points in the stomach mixed carcinomas. Methods: Immun... Objective: The aim of the study was to investigate the human epidermal growth factor receptor 2(HER2) gene amplification and protein expression and interpretation points in the stomach mixed carcinomas. Methods: Immunohistochemistry(IHC) and fluorescence in situ hybridization(FISH) technique were used to detect HER2 gene amplification and expression of HER2 protein in 442 cases of gastric mixed carcinoma. Results: The expression rate of HER2 protein was 41.2%(182/442): the HER2 protein expression IHC 3+ extensive type in 18 cases, partial type in 21 cases, focal type in 8 cases, accounting for 10.6%(47/442); the HER2 protein expression IHC 2+ extensive type in 23 cases, partial type in 28 cases, focal type in 11 cases, accounting for 14.0%(62/442); the HER2 protein expression IHC 1+ extensive type in 27 cases, partial type in 31 cases, focal type in 15 cases, accounting for 16.5%(73/442). HER2 gene amplification rate of 442 cases was 16.1%(71/442). In 182 cases of HER2 protein positive expression, the HER2 gene cluster amplification rate was 14.8%(27/182), large granular amplification rate 11.0%(20/182), punctate amplification rate 6.0%(11/182) and high polysomy 7.1%(13/182). In 71 cases of HER2 gene amplification, there was 42 cases of HER2 protein expression IHC 3+, 22 cases of HER2 protein expression IHC 2+, and 7 cases of IHC 1+. Conclusion: HER2 detection of gastric mixed carcinoma has great heterogeneity, HER2 protein positive expression is divided into extensive type, partial type and focal type, and HER2 gene positive amplification is divided into cluster amplification, large granular amplification, punctate amplification and high polysomy. These typing of HER2 protein expression and HER2 gene amplification provide reference index to quantify for targeted therapeutic effect of anticancer drugs. 展开更多
关键词 stomach neoplasms mixed tumor human epidermal growth factor receptor 2 (HER2) gene HER2 proteinfluorescence in situ hybridization (FISH) immunohistochemistry (IHC)
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Increased expression of neuropeptide Y and its mRNA in STZ-diabetic rats 被引量:1
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作者 傅茂 李秀钧 +1 位作者 鲜杨 张敏 《Chinese Medical Journal》 SCIE CAS CSCD 2002年第5期690-695,149,共6页
OBJECTIVE: To study the relationship between neuropeptide Y (NPY) and diabetes by examining the content and distribution of NPY and its mRNA expression in the hypothalamus and pancreas of STZ-diabetic rats. METHODS: T... OBJECTIVE: To study the relationship between neuropeptide Y (NPY) and diabetes by examining the content and distribution of NPY and its mRNA expression in the hypothalamus and pancreas of STZ-diabetic rats. METHODS: Thirty Wistar rats were randomly divided into 3 groups (diabetic group, diabetic insulin treatment group, and control group). After feeding for 24 weeks, the rats were sacrificed. The expression of NPY in the hypothalamus and pancreas was detected with immunohistochemistry and in situ hybridization. RESULTS: (1) The hypothalamic content of NPY and its mRNA were significantly increased in STZ-diabetic rats in comparison with normal controls. Increased expression of NPY mRNA was found only in the arcuate nucleus and not in the paraventricular nucleus in diabetic rats, suggesting that NPY was produced in the arcuate nucleus. (2) The hypothalamic content of NPY and its mRNA in STZ-diabetic rats were visibly reduced after insulin treatment compared with that in untreated diabetic rats. This supports the hypothesis that insulin deficiency in the brain may be responsible for increased hypothalamic NPY gene expression in diabetic rats. (3) The increase of hypothalamic NPY in STZ diabetic rats associated with hyperphagia and polydipsia could be reversed by insulin replacement, suggesting that increased hypothalamic NPY contributes to the pathophysiological progress of the diabetic state. (4) The present study demonstrated for the first time that the content of NPY and its mRNA in the pancreas was increased in STZ-diabetic rats, and that the distribution of NPY-positive cell in islets was changed from the periphery to the whole islet. The content and distribution of NPY and its mRNA in islets were not changed by insulin treatment. CONCLUSION: Increased NPY in the hypothalamus results in hypophagia and polydipsia, while the implication of increased NPY in the pancreas of diabetic rats is not clear. 展开更多
关键词 Animals Blood Glucose Diabetes Mellitus Experimental Drinking EATING Female Gene Expression Regulation HYPOTHALAMUS Immunohistochemistry In Situ Hybridization Insulin Neuropeptide Y Pancreas RNA Messenger RATS Rats Wistar Research Support Non-U.S. Gov't
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In situ localization of procollagen gene expression on cryosections of undecalcified fracture callus
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作者 史炜镔 杜宁 +3 位作者 符诗聪 张昊 程枫 柴本甫 《Chinese Journal of Traumatology》 CAS 2000年第1期26-29,共4页
To analyze the expression of procollagen gene in fracture callus, and to search for the technique of in situ hybridization for undecalcified skeletal tissue. Methods: In situ hybridization of procollagen gene expres... To analyze the expression of procollagen gene in fracture callus, and to search for the technique of in situ hybridization for undecalcified skeletal tissue. Methods: In situ hybridization of procollagen gene expression was performed on the undecalcified cryosections of rat fracture callus at 7, 14, and 28 d. Results: The hybridization signals achieved were clear and easy to be localized with high specificity. On the 7th day, the expressions of pro α1(Ⅲ) in fibroblasts and some chondrocyte like cells were dominant; and at the end of second week high expression of type Ⅱ procollagen mRNA was observed in chondrocytes. At the end of fourth week, the cartilaginous callus was almost all replaced by woven bone tissue, and some type Ⅰ procollagen mRNA positive osteoblasts and hypertrophic chondrocytes were found scattering in the woven bone and remnants of cartilaginous callus.Conclusions: The modified method employed in this study is easier, quicker, and more sensitive with high specificity than the conventional technique for in situ hybridization of procollagen gene expression of decalcified rat fracture callus. The phenomenon of shared phenotype expression, which was demonstrated among cells engaged in fracture healing, indicates an important approach to reveal the mechanism of the origin, differentiation, and orientation of cells. 展开更多
关键词 FRACTURES CALLUS In situ hybridization PROCOLLAGEN Gene expression
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