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改进的Pattern Matrix算法在图书管理中的应用
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作者 虞智辉 《电脑知识与技术》 2013年第11X期7577-7580,共4页
根据用户的信息和图书借阅所产生的数据,分析用户的需求,利用改进的Pattern Matrix算法,从中挖掘出用户数据间的关联性,自动判断用户可能的借阅需求,从而将相关的图书信息推送给用户,增强图书管理的主动服务功能。
关键词 数据分析 数据挖掘 pattern matrix算法 改进
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Pattern Matrix Design of PDMA for 5G UL Applications 被引量:4
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作者 Bin Ren Yingmin Wang +2 位作者 Xiaoming Dai Kai Niu Wanwei Tang 《China Communications》 SCIE CSCD 2016年第S2期159-173,共15页
Pattern division multiple access(PDMA),which is a novel non-orthogonal multiple access(NOMA),has been proposed to address the challenges of massive connectivity and higher spectral efficiency for fifth generation(5G) ... Pattern division multiple access(PDMA),which is a novel non-orthogonal multiple access(NOMA),has been proposed to address the challenges of massive connectivity and higher spectral efficiency for fifth generation(5G) mobile network.The performance of PDMA mainly depends on the design of PDMA pattern matrix.In this paper,pattern matrix design of PDMA for 5G uplink(UL) applications in massive machine type communication(mMTC) and enhanced mobile broadband(eMBB) deployment scenarios are studied.The design criteria and examples for application in UL mMTC and UL eMBB are investigated.The performance of the PDMA pattern matrix is analyzed with the discrete constellation constrained capacity(CC-Capacity),and verified by Monte Carlo simulation.The simulation results show that the preferred PDMA pattern matrix can achieve good performance with different overloading factors(OF). 展开更多
关键词 5G non-orthogonal multiple access PDMA pattern matrix CC-Capacity SIC
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Sign Patterns That Allow the Given Matrix
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作者 邵燕灵 孙良 《Journal of Beijing Institute of Technology》 EI CAS 2003年第3期316-318,共3页
Let P be a property referring to a real matrix. For a sign pattern A, if there exists a real matrix B in the qualitative class of A such that B has property P, then we say A allows P. Three cases that A allows an M m... Let P be a property referring to a real matrix. For a sign pattern A, if there exists a real matrix B in the qualitative class of A such that B has property P, then we say A allows P. Three cases that A allows an M matrix, an inverse M matrix and a P 0 matrix are considered. The complete characterizations are obtained. 展开更多
关键词 sign pattern M matrix inverse M matrix P 0 matrix
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FUZZY WITHIN-CLASS MATRIX PRINCIPAL COMPONENT ANALYSIS AND ITS APPLICATION TO FACE RECOGNITION 被引量:3
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作者 朱玉莲 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2008年第2期141-147,共7页
Matrix principal component analysis (MatPCA), as an effective feature extraction method, can deal with the matrix pattern and the vector pattern. However, like PCA, MatPCA does not use the class information of sampl... Matrix principal component analysis (MatPCA), as an effective feature extraction method, can deal with the matrix pattern and the vector pattern. However, like PCA, MatPCA does not use the class information of samples. As a result, the extracted features cannot provide enough useful information for distinguishing pat- tern from one another, and further resulting in degradation of classification performance. To fullly use class in- formation of samples, a novel method, called the fuzzy within-class MatPCA (F-WMatPCA)is proposed. F-WMatPCA utilizes the fuzzy K-nearest neighbor method(FKNN) to fuzzify the class membership degrees of a training sample and then performs fuzzy MatPCA within these patterns having the same class label. Due to more class information is used in feature extraction, F-WMatPCA can intuitively improve the classification perfor- mance. Experimental results in face databases and some benchmark datasets show that F-WMatPCA is effective and competitive than MatPCA. The experimental analysis on face image databases indicates that F-WMatPCA im- proves the recognition accuracy and is more stable and robust in performing classification than the existing method of fuzzy-based F-Fisherfaces. 展开更多
关键词 face recognition principal component analysis (PCA) matrix pattern PCA(MatPCA) fuzzy K-nearest neighbor(FKNN) fuzzy within-class MatPCA(F-WMatPCA)
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PU基体和吸波材料热带海洋大气环境下力学性能变化规律研究
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作者 罗丹 吴欣睿 +5 位作者 任宏宇 李昊瑜 李旭 彭冬 李晗 李鸿飞 《环境技术》 2026年第1期18-22,共5页
为研究PU基体和吸波材料在热带海洋大气环境下的力学性能变化规律。在某试验站采用黑箱暴露贮存方式开展1年的暴露贮存试验,分别通过拉伸强度与断裂伸长率研究其力学性能变化规律。PU基体和吸波材料在1年的黑箱暴露贮存试验下,其力学性... 为研究PU基体和吸波材料在热带海洋大气环境下的力学性能变化规律。在某试验站采用黑箱暴露贮存方式开展1年的暴露贮存试验,分别通过拉伸强度与断裂伸长率研究其力学性能变化规律。PU基体和吸波材料在1年的黑箱暴露贮存试验下,其力学性能呈总体下降趋势,并在贮存1年左右就发生了明显的粉化现象。而吸波材料的防水覆膜对材料具有明显的保护作用,大大降低了对空气中水汽的敏感性。吸波材料在热带海洋大气环境下的力学性能优于PU基体。 展开更多
关键词 PU基体 吸波材料 热带海洋大气环境 力学性能变化规律
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安阳市土地利用景观格局时空演变特征及驱动因素分析
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作者 赵冬 郭兰博 +3 位作者 王业宁 陈心旸 王爱国 闫丽洁 《资源与产业》 2026年第1期118-128,共11页
城市化加速了土地利用景观格局的演变,而合理分析城市生态风险对保护城市生态环境和实现城市可持续发展具有重要意义。论文以河南省安阳市为研究区,采用土地利用转移矩阵、景观格局指数和热点分析等方法,并基于2000—2020年安阳市土地... 城市化加速了土地利用景观格局的演变,而合理分析城市生态风险对保护城市生态环境和实现城市可持续发展具有重要意义。论文以河南省安阳市为研究区,采用土地利用转移矩阵、景观格局指数和热点分析等方法,并基于2000—2020年安阳市土地利用数据,对安阳市土地利用景观格局演变特征进行分析,并利用主成分分析方法确定演化的主要驱动因素。研究结果表明:1)2000—2020年,安阳市土地利用演变格局呈现“三增两减”的趋势,即耕地、林地减少,草地、水域、建设用地增加,以耕地与建设用地之间的相互转化最为明显;2)2000—2020年,安阳市景观生态高风险区面积增加6 170.52 km^(2),景观生态风险等级逐渐升级,热点区域位于安阳市市区;3)2000—2010年,景观生态低风险区转向较高风险区,而2010—2020年景观生态较高风险区转向高风险区;4)景观格局演化是城市化水平指数、经济因子指数和人口密度共同作用的结果,产业结构因子对景观格局演化也有一定的影响。建议安阳市在城市化进程中,既要重视生态保护,又要因地制宜制定适宜区域土地利用良性发展的政策。 展开更多
关键词 转移矩阵 景观格局指数 热点分析 主成分分析 安阳市
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集群天线阵列:从确定性到随机建模
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作者 密铁宾 冯密宇 +2 位作者 邵睿初 曾操 邱才明 《电子科技大学学报》 北大核心 2026年第1期65-76,共12页
集群天线阵列由部署于无人平台的分布式天线单元构成,为无线感知与通信提供了前所未有的灵活性与环境适应性。然而,分布式架构及无人平台位置的随机扰动削弱了多天线单元的协同增益,对实现相干信号合成构成了严峻挑战。集群天线的空间... 集群天线阵列由部署于无人平台的分布式天线单元构成,为无线感知与通信提供了前所未有的灵活性与环境适应性。然而,分布式架构及无人平台位置的随机扰动削弱了多天线单元的协同增益,对实现相干信号合成构成了严峻挑战。集群天线的空间拓扑结构、平台的位置扰动以及天线规模对信号聚合性能的影响机理尚不明确。该文从确定性与随机性双重视角出发,探究集群天线阵列实现波束赋形的可行性。首先,针对多线性形式的集群天线阵列结构,构建了理论分析框架,推导了该类天线拓扑在波束合成过程中产生栅瓣的充要条件。对于双线性天线阵列,在不引入栅瓣的前提下,可放宽经典的半波长间距约束。该结论突破了传统均匀线性阵列设计中关于栅瓣抑制必须满足半波长间距的固有准则。随后,系统研究了天线位置扰动对波束赋形性能的影响。结果表明,天线的位置扰动将导致主瓣增益下降,主瓣增益的衰减无法通过单纯增加天线规模予以有效补偿;相反,增大天线规模的主要作用在于抑制旁瓣电平的波动方差,提升波束方向图的稳定性。最后,基于欧几里得随机矩阵的谱分析方法,研究了大规模无序天线阵列中涌现的确定性行为。当天线位置服从某种完全随机的空间分布时,其对应的欧几里得随机矩阵经验谱分布在天线数量趋于无穷时,几乎必然收敛于一个确定性极限。该结果揭示了无序天线阵列结构中蕴含的内在规律性,为后续大规模无序天线阵的建模与性能分析提供了必要的数学工具。 展开更多
关键词 集群天线阵列 阵列方向图 波束赋形 相位补偿 扰动 欧几里得随机矩阵
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激光微孔化脱细胞支架在组织再生中的应用
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作者 顾健美 袁坤山 +1 位作者 周强 张海军 《中国组织工程研究》 北大核心 2026年第2期499-506,共8页
背景:在组织工程领域,脱细胞支架因生物相容性良好而被广泛应用;然而,由于其结构致密,它们常常面临细胞浸润不足的挑战。采用激光微孔加工技术对脱细胞支架进行结构改性,能够改善细胞的黏附与增殖。目的:总结激光微孔化脱细胞支架在组... 背景:在组织工程领域,脱细胞支架因生物相容性良好而被广泛应用;然而,由于其结构致密,它们常常面临细胞浸润不足的挑战。采用激光微孔加工技术对脱细胞支架进行结构改性,能够改善细胞的黏附与增殖。目的:总结激光微孔化脱细胞支架在组织再生中的研究进展。方法:在中国知网和PubMed数据库中检索相关文献,中文检索词为“脱细胞支架、激光微图技术、激光微孔化脱细胞支架、细胞外基质、激光打孔、组织再生”,英文检索词为“decellularized scaffold、laser micro-patterning technology、laser microporous decellularized scaffold、extracellular matrix、laser drilling、tissue regeneration”。根据纳入与排除标准筛选文献,最终纳入65篇文献进行分析与讨论。结果与结论:①激光微图技术可以选择性去除组织实现支架改性,激光处理对支架的孔隙结构、机械性能、细胞渗透性均会产生影响且影响可控。②为了获得最优的细胞整合与重塑效果,应考虑支架预处理、激光与脱细胞技术工艺顺序、激光参数设定、脱细胞工艺和孔隙结构因素。③目前,激光微孔化脱细胞支架的应用显示其可以促进组织修复,但需要解决组织热损伤的问题,根据组织对不同波长激光的吸收,合理选择激光类型是一种可行的解决方案。④激光微孔化脱细胞支架进行组织损伤修复有望实现临床转化,优化激光工艺、开展更大规模的生物安全性测试是未来的研究方向。 展开更多
关键词 脱细胞支架 激光微图技术 细胞外基质 激光打孔 组织损伤 再细胞化 组织再生 工程化生物材料 组织工程
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THE STRUCTURE OF TRIPOTENT SIGN PATTERN MATRICES 被引量:2
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作者 Li Jiongsheng Gao Yubin Project supported by the National Natural Science Foundation of China (19971086).Dept. of Math., Univ. of Science and Technology of China, Hefei 230026 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2001年第1期1-7,共7页
A matrix whose entries are +,-, and 0 is called a sign pattern matrix. For a sign pattern matrix A , if A 3=A , then A is said to be sign tripotent. In this paper, the characterization of the n by n(n... A matrix whose entries are +,-, and 0 is called a sign pattern matrix. For a sign pattern matrix A , if A 3=A , then A is said to be sign tripotent. In this paper, the characterization of the n by n(n≥2) sign pattern matrices A which are sign tripotent has been given out. Furthermore, the necessary and sufficient condition of A 3=A but A 2≠A is obtained, too. 展开更多
关键词 SIGN pattern matrix.
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Electromagnetic Field Released in Collision-Impact Events Generate in the Matrix Interface Fractal Scalable Invariant Geometric Triangular Chiral Hexagonal Structures 被引量:2
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作者 Jairo A. Diaz 《Open Journal of Geology》 2013年第3期187-200,共14页
In biology, cancer is the most beautiful natural model of a chaotic system, which under uncontrolled proliferations, generates extreme disorder that finally causes intercellular collisions. The authors have described ... In biology, cancer is the most beautiful natural model of a chaotic system, which under uncontrolled proliferations, generates extreme disorder that finally causes intercellular collisions. The authors have described and documented fractal self-assembly of geometric triangular chiral hexagonal crystal-like complex organizations (GTCHC) and interface comet tail effect patterns in cancer processes. According to this novel observation cancer incorporates a real visualization world with a great surprising finding in biology, physics, and geology. This visualization platform literally allows us to see what would otherwise remain completely invisible. From theory to practice this irreducible geometric matrix allowed us to identify in geology, real measurable green infrared-electromagnetic stripe line in interface with hexagonal geomorphic pattern, triangular chiral pyramidal rock structures, geology well defined mirror images, template platform to bio signature characterization of ancestral primitive polar head-tail organization, embryoid and human-like shape pattern embedded as giant fossils in rocks that have never been seen before. Electromagnetic field released in collision-impact events generate in the matrix interphase fractal scalable invariant order of geometric triangular chiral hexagonal structures. The laws of biology and geology can finally be redirected to the laws of physics;specifically magnetic fields create a new kind of classification based on these fractal structural similarities of the relationship. Further interdisciplinary collaboration must be carried out to study these geometric self-assembly geological structures, ancient sediments and rocks that could provide insights into antecedents of life. 展开更多
关键词 Electromagnetic Fields Geomorphic patterns IRREDUCIBLE GEOMETRIC matrix
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A complete compilation of matrix metalloproteinase expression in human malignant gliomas 被引量:19
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作者 Carsten Hagemann Jelena Anacker +1 位作者 Ralf-Ingo Ernestus Giles H Vince 《World Journal of Clinical Oncology》 CAS 2012年第5期67-79,共13页
Glioblastomas are characterized by an aggressive local growth pattern, a marked degree of invasiveness and poor prognosis. Tumor invasiveness is facilitated by the increased activity of proteolytic enzymes which are i... Glioblastomas are characterized by an aggressive local growth pattern, a marked degree of invasiveness and poor prognosis. Tumor invasiveness is facilitated by the increased activity of proteolytic enzymes which are involved in destruction of the extracellular matrix of the surrounding healthy brain tissue. Elevated levels of matrix metalloproteinases(MMPs) were found in glioblastoma(GBM) cell-lines, as well as in GBM biopsies as compared with low-grade astrocytoma(LGA) and normal brain samples, indicating a role in malignant progression. A careful review of the available literature revealed that both the expression and role of several of the 23 human MMP proteins is controversely discussed and for some there are no data available at all. We therefore screened a panel of 15 LGA and 15 GBM biopsy samples for those MMPs for which there is either no, very limited or even contradictory dataavailable. Hence, this is the first complete compilation of the expression pattern of all 23 human MMPs in astrocytic tumors. This study will support a better understanding of the specific expression patterns and interaction of proteolytic enzymes in malignant human glioma and may provide additional starting points for targeted patient therapy. 展开更多
关键词 Astrocytic tumor EXPRESSION pattern GLIOBLASTOMA CELL-LINES GLIOBLASTOMA MULTIFORME matrix METALLOPROTEINASE
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INERTIA SETS OF SYMMETRIC SIGN PATTERN MATRICES
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作者 Frank J.Hall +1 位作者 Li 李忠尚 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2001年第2期226-240,共15页
A sign pattern matrix is a matrix whose entries are from the set {+,-,0}. The symmetric sign pattern matrices that require unique inertia have recently been characterized. The purpose of this paper is to more generall... A sign pattern matrix is a matrix whose entries are from the set {+,-,0}. The symmetric sign pattern matrices that require unique inertia have recently been characterized. The purpose of this paper is to more generally investigate the inertia sets of symmetric sign pattern matrices. In particular, nonnegative tri-diagonal sign patterns and the square sign pattern with all + entries are examined. An algorithm is given for generating nonnegative real symmetric Toeplitz matrices with zero diagonal of orders n≥3 which have exactly two negative eigenvalues. The inertia set of the square pattern with all + off-diagonal entries and zero diagonal entries is then analyzed. The types of inertias which can be in the inertia set of any sign pattern are also obtained in the paper. Specifically, certain compatibility and consecutiveness properties are established. 展开更多
关键词 inertia SIGN pattern matrix INERTIA set UNIQUE inertia TOEPLITZ matrix.
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ELECTRON DIFFRACTION PATTERNS ANALYSIS OF PRECIPITATES IN LD_(10) ALLOY
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作者 Jin, Tounan Yin, Zhimin(Department of Materials Science and Engineering,Central South University of Technology, Changsha 410083) 《中国有色金属学会会刊:英文版》 CSCD 1995年第3期119-123,共5页
ELECTRONDIFFRACTIONPATTERNSANALYSISOFPRECIPITATESINLD_(10)ALLOY¥Jin,Tounan;Yin,Zhimin(DepartmentofMaterialsS... ELECTRONDIFFRACTIONPATTERNSANALYSISOFPRECIPITATESINLD_(10)ALLOY¥Jin,Tounan;Yin,Zhimin(DepartmentofMaterialsScienceandEngineer?.. 展开更多
关键词 PRECIPITATE SIMULATED DIFFRACTION pattern TRANSFORMATION matrix
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LANDSCAPE PATTERN CHANGES IN WEST SUBURBS OF SHENYANG
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作者 肖笃宁 赵羿 郭林海 《Chinese Geographical Science》 SCIE CSCD 1994年第3期277-288,共12页
Spatial pattern of landscape is a central issue in landscape ecology study. The main reason of landscape patten change owes to the external disturbance. In this article, retrospective sequential airphotoanalysis and s... Spatial pattern of landscape is a central issue in landscape ecology study. The main reason of landscape patten change owes to the external disturbance. In this article, retrospective sequential airphotoanalysis and statistical analysis of information on landscape development were used and two remarkable changes of landscape pattern in west Shenyang were identified: (a) one landscape element becomes a new matrix in place of the former one; (b) landscape proportions among several constiting elements changed significantly. This paper studied spatial pattern of the landscape using following quanta indices: (1) number and size of patches, (2) transition matrix of patches, (3) priority index of each kind of patch and (4) diversity and evenness indices of landscape.The results show that the landscape of west Shenyang has been more and more disturbed by human activities, so it becomes fragmentary throughout 30 years, and many blocky and island-like patches emerged. 展开更多
关键词 SUBURB LANDSCAPE spatial pattern PRIORITY index transition matrix human DISTURBANCE
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Analysis of Land Cover and Landscape Pattern Change in Beijing-Tianjin-Hebei Region Based on Globeland30 Data
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作者 Yimeng Shi Hongli Song +2 位作者 Ming Shang Mingchao Shao Haimei Lei 《Journal of Geographic Information System》 2020年第3期241-255,共15页
With the rapid economic development and urbanization process in Beijing-Tianjin-Hebei region, land use and landscape pattern have been changed. In order to reveal the temporal and spatial changes and provide scientifi... With the rapid economic development and urbanization process in Beijing-Tianjin-Hebei region, land use and landscape pattern have been changed. In order to reveal the temporal and spatial changes and provide scientific basis for the local land use planning and landscape pattern optimization made by government, based on the classification results of Globeland 30 land cover data in 2000 and 2010, this paper quantitatively analyzed the land use transfer status and the dynamic change of landscape pattern in Beijing-Tianjin-Hebei by adopting the method of land use transfer matrix and landscape index. The results show that the land use and landscape patterns in Beijing-Tianjin-Hebei have been changed significantly from 2000 to 2010. Overall, land use in Beijing-Tianjin-Hebei region has been changed greatly, which shows that the cultivated land area has been decreased by 3721.67 km<sup>2</sup>, while the artificial surface area and grassland area have increased by 2721.29 km<sup>2</sup> and 657.09 km<sup>2</sup>, respectively. From the six partitions of Beijing-Tianjin-Hebei, it can be seen that the subareas with significant changes are Sand Control Farmland Protection Zone in Yellow River Flood Plain, Water Conservation Area for Sand Control in Mountain and Hilly Areas of Northwest Taihang Mountains, and Human Settlement Environment Maintenance and Farmland Protection Zone of Beijing-Tianjin-Hebei Urban Agglomeration. The arable land area of these three zones has decreased 572.77 km<sup>2</sup>, 1553.94 km<sup>2</sup> and 1359.53 km<sup>2</sup>, respectively. From the perspective of landscape pattern change, patch density and fragmentation degree in the southeast and northwest of Beijing-Tianjin-Hebei region increase;and the dominant patches in the southeast of Beijing-Tianjin-Hebei region have formed a good connectivity;the whole Beijing-Tianjin-Hebei region shows irregular shape and discontinuous enhancement of landscape types, the landscape patch types increase and enrich, and the dominance shows a downward trend. 展开更多
关键词 Land Use Transfer matrix Landscape pattern Landscape Index Globeland30
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Landscape pattern change of a typical region in the Kubuqi Desert, Northwestern China
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作者 CUI Bu-li CHANG Xue-li LI Xiao-yan 《地球环境学报》 2012年第6期1165-1173,共9页
Spatial pattern analysis is the core component in landscape ecology research.We analyzed the landscape pattern and dynamic process of the Kubuqi Desert by using a typical region as a study area.This study area include... Spatial pattern analysis is the core component in landscape ecology research.We analyzed the landscape pattern and dynamic process of the Kubuqi Desert by using a typical region as a study area.This study area includes four towns;ShuLinZhao,WangAiZhao,BaiNiJing and JiGeSiTai.The area of cropland,fixed sand dune,woodland,residential area and wetland increased and centralized gradually,while the area of semi-fixed sand dune,drifting sand dune,meadow and washland decreased and dispersed gradually from 1987 to 2003.On the landscape level,the patch shape tended to be regular,and the landscape pattern tended to be simple,causing the fragmentation degree,heterogeneity and diversity of the landscape to decrease.Fixed sand dune.Semi-fixed sand dune,drifting sand dune,meadow and river flood plains were the five main export classes,and residential area,cropland and wetland were the three main import classes.The classes that had a relatively large total area and large average patch area had a smaller extent of gravity center migration,whereas the classes with small total area and small average patch area had a larger extent of gravity center migration;this is because the small patches are easily influenced by human activities or natural factors.In addition,the desertification area and desertification degree reduced gradually in the study area during the period from 1987 to 2003. 展开更多
关键词 Landscape pattern gravity center migration transfer matrix landscape index the Kubuqi Desert
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基于ChaffMatrix的光载声音声纹变化识别系统设计
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作者 白曦龙 冯佳 《激光杂志》 CAS 北大核心 2022年第1期174-178,共5页
采集光载声音时会受到激光传输信道噪声的干扰,传统声纹变化识别系统对于信道噪声的去噪效果不好,影响最终的声纹识别准确性,因此,设计一种基于ChaffMatrix的光载声音声纹变化识别系统。系统沿用传统系统的硬件设计,主要对于软件方面进... 采集光载声音时会受到激光传输信道噪声的干扰,传统声纹变化识别系统对于信道噪声的去噪效果不好,影响最终的声纹识别准确性,因此,设计一种基于ChaffMatrix的光载声音声纹变化识别系统。系统沿用传统系统的硬件设计,主要对于软件方面进行详细研究。首先对一段语音端点进行检测,采用单门限阈值法来检测能量端点,排除噪声优化计算量,提高检测准确度,设计基于ChaffMatrix的声纹模板转换成伪矩阵的音频信号尺度来反映频谱系数的频率范围,作为系统后端识别部分的输入,最后通过改变人工神经网络的结构来优化声纹识别算法,将原有的单层结构改变成多层结构,模拟生物神经元的互联过程,完成声纹降噪。仿真实验的结果表明,设计的系统相对于ANN-VQ系统、CS算法系统、改进谱减法系统三个原有系统来说,具有更好的去噪性能。 展开更多
关键词 光载声音 声纹变化识别 系统设计 伪矩阵
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天基ISAR空间目标重构算法
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作者 王勇 周奕辰 《哈尔滨工业大学学报》 北大核心 2025年第12期283-293,共11页
面向在轨目标的天基逆合成孔径雷达(ISAR)成像是空间态势感知(SSA)的一项关键支撑技术。传统的二维距离-多普勒(RD)图像虽可部分揭示目标的散射特性,但其本质缺乏预测轨道机动和实现非合作目标识别所必需的三维几何信息。而现有基于图... 面向在轨目标的天基逆合成孔径雷达(ISAR)成像是空间态势感知(SSA)的一项关键支撑技术。传统的二维距离-多普勒(RD)图像虽可部分揭示目标的散射特性,但其本质缺乏预测轨道机动和实现非合作目标识别所必需的三维几何信息。而现有基于图像序列的多视角重构方法在天基应用场景下存在固有局限:天基平台与目标卫星间的相对轨道运动会造成有效观测时间受限与成像投影平面不稳定的问题。为应对上述挑战,提出一种可变观测模式的目标重构算法。首先,该算法直接利用各特显点距离徙动(RM)轨迹中蕴含的目标结构信息,规避了易引入误差的图像配准过程。其次,推导了二维与三维旋转模式下距离徙动轨迹的表征模型,并提取了用于旋转模式分类的判别特征。最后,提出一种基于高阶多普勒系数估计的高精度距离徙动估计技术;对于不同的旋转模式,结合截断核范数正则化的因式分解方法可实现受观测误差影响时的二维或三维目标重构。仿真结果表明,所提空间目标重构算法可有效实现散射点提取以及距离徙动矩阵重建,进一步实现距离徙动矩阵的正则化收敛,从而获得不同旋转状态下空间目标重构结果,验证了所提算法的有效性与灵活性。 展开更多
关键词 空间态势感知 天基ISAR 目标重构 旋转模式判决 矩阵正则化
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基于RSCM与黎曼空间的运动想象脑电分类研究 被引量:1
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作者 廉小亲 刘春权 +2 位作者 高超 邓子谦 吴叶兰 《电子测量技术》 北大核心 2025年第9期84-93,共10页
近年来,运动想象(MI)在辅助医疗和人机交互领域备受关注。然而,经典的共空间模式(CSP)特征提取方法主要基于时域信号计算协方差矩阵(CM),易受噪声和伪迹干扰,且无法充分利用脑电信号(EEG)的频谱信息,导致分类精度与稳定性不足。为了解... 近年来,运动想象(MI)在辅助医疗和人机交互领域备受关注。然而,经典的共空间模式(CSP)特征提取方法主要基于时域信号计算协方差矩阵(CM),易受噪声和伪迹干扰,且无法充分利用脑电信号(EEG)的频谱信息,导致分类精度与稳定性不足。为了解决这一问题,本研究提出了一种基于正则化频谱协方差矩阵(RSCM)与黎曼空间的MI-EEG分类算法。首先,对预处理后的EEG信号进行快速傅里叶变换,计算频谱协方差矩阵,并进行岭正则化;然后,将正则化矩阵映射到切空间中进行平滑滤波,并将结果映射回黎曼空间以提取CSP特征;最后,采用支持向量机(SVM)完成分类任务。实验结果表明,在BCI竞赛IV数据集1和2a上,本研究方法的二分类平均准确率分别达到了86.95%和81.48%,较传统CSP分别提升了7.44%和9.57%;在BCI竞赛IV数据集2a上,本研究方法的四分类平均准确率达到了74.23%,较传统CSP方法提升了14.10%。实验结果表明,本研究方法在MI-EEG分类中具有有效性。 展开更多
关键词 运动想象 脑电信号 频谱协方差矩阵 黎曼空间 共空间模式
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Assessment of Structural Damage Condition Based on Fuzzy Pattern Recognition
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作者 WU Zi-yan ZHANG Yu 《International Journal of Plant Engineering and Management》 2008年第1期10-19,共10页
This paper presents a new method of damage condition assessment that allows accommodating other types of uncertainties due to ambiguity, vagueness, and fuzziness that are statistically nondescribable. In this method, ... This paper presents a new method of damage condition assessment that allows accommodating other types of uncertainties due to ambiguity, vagueness, and fuzziness that are statistically nondescribable. In this method, healthy observations are used to construct a fury set representing sound performance characteristics. Additionally, the bounds on the similarities among the structural damage states are prescribed by using the state similarity matrix. Thus, an optimal group fuzzy sets representing damage states such as little, moderate, and severe damage can be inferred as an inverse problem from healthy observations only. The optimal group of damage fuzzy sets is used to classify a set of observations at any unknown state of damage using the principles of fitzzy pattern recognition based on an approximate principle . This method can be embedded into the system of Structural Health Monitoring (SHM) to give advice about structural maintenance and life predictio comes from Reference [ 9 ] for damage pattern recognition is presented n. Finally, a case and discussed. The study, which compared result illustrates our method is more effective and general, so it is very practical in engineering. 展开更多
关键词 damage condition assessment fuzzy pattern recognition state similarity matrix approximate principle structural health monitoring
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