期刊文献+
共找到31篇文章
< 1 2 >
每页显示 20 50 100
基于多碱基组合映射编码和DNA计算的一次一密算法 被引量:4
1
作者 彭维平 程丹华 宋成 《计算机应用研究》 CSCD 北大核心 2019年第7期2190-2194,共5页
为增强密码方案安全性,利用多碱基组合映射编码,采用模拟DNA生物操作的方式,提出了一种一次一密加/解密方案。方案主要采用分段加密的机制,利用多碱基组合映射编码规则编码明文信息,通过logistic逻辑映射系统生成随机数构造一次一密密钥... 为增强密码方案安全性,利用多碱基组合映射编码,采用模拟DNA生物操作的方式,提出了一种一次一密加/解密方案。方案主要采用分段加密的机制,利用多碱基组合映射编码规则编码明文信息,通过logistic逻辑映射系统生成随机数构造一次一密密钥本,为每一个明文段选择不同的密钥。加/解密算法运用DNA碱基运算规则,并将部分参数和最终密文经过处理后通过安全信道传送给解密方。对图像仿真和安全性的分析表明,密钥本的制作基于混沌映射和多碱基DNA编码规则两层操作,密钥空间足够大,并且攻击者在密文图像中得不到任何有用的统计数据。另外,随着需要加密的明文数据量增加,攻击者完全破解所需计算的密钥空间量呈指数级增长,增强了算法安全性。 展开更多
关键词 DNA密码 LOGISTIC映射 多碱组合映射 一次一密密钥本 图像加密
下载PDF
基亚紧映射与基中紧映射 被引量:1
2
作者 王荣欣 王尚志 牟磊 《河北师范大学学报(自然科学版)》 CAS 北大核心 2009年第1期25-27,共3页
引入了基亚(中)紧空间和基亚(中)紧映射的概念,并研究了完备映射、闭Lindel f映射、基仿紧映射、基亚紧映射、基中紧映射对基亚紧性和基中紧性的保持问题.
关键词 亚紧空间 中紧空间 亚紧映射 中紧映射
下载PDF
基-中紧映射性质和基-可数中紧乘积性质 被引量:1
3
作者 纪广月 《广州大学学报(自然科学版)》 CAS 2012年第1期10-12,共3页
引入了基-中紧映射,并证明了如下结果:①设f:X→Y是闭Lindelff映射,若X为正则空间,则f:X→Y是基-中紧映射;②若X和Y都为基-可数中紧的,Y为局部紧的,则X×Y为基-可数中紧的.
关键词 闭Lindelsff映射 一中紧映射 一可数中紧
下载PDF
基-可数亚紧映射
4
作者 纪广月 《西南民族大学学报(自然科学版)》 CAS 2011年第6期873-874,共2页
引入了基-可数亚紧映射,证明了在ω(X)≥ω(Y)下,基-可数亚紧映射f:X→Y逆保持基-可数亚紧性;在既开又闭的有限到一的映射下,基-可数亚紧具有保持性.
关键词 -可数亚紧空间 -可数亚紧映射
下载PDF
格值Fuzzifying连续映射的若干性质 被引量:1
5
作者 王书臣 张杰 《哈尔滨师范大学自然科学学报》 CAS 2003年第4期26-28,共3页
本文讨论了L -fuzzifying连续映射 ,L -fuzzifying基连续映射和L -fuzzifying子基连续映射的若干性质及等价刻划 .
关键词 L-fuzzifying拓扑空间 L-fuzzifying连续映射 L-fuzzifying子连续映射 L-fuzzifying连续映射 拓扑
下载PDF
基-可数中紧空间的闭逆象 被引量:1
6
作者 贾永进 《湖北民族学院学报(自然科学版)》 CAS 2007年第3期260-262,共3页
引入了基-可数中紧映射,并且获得了如下主要结果:(i)设X,Y为T2空间,ω(X)≥ω(Y),f∶X→Y是基-可数中紧映射,如果Y是正则的基-可数中紧空间,那么X是基-可数中紧空间.(ii)设f∶X→Y是闭Lindelf映射,若X为正则空间,则f∶X→Y是基-可数... 引入了基-可数中紧映射,并且获得了如下主要结果:(i)设X,Y为T2空间,ω(X)≥ω(Y),f∶X→Y是基-可数中紧映射,如果Y是正则的基-可数中紧空间,那么X是基-可数中紧空间.(ii)设f∶X→Y是闭Lindelf映射,若X为正则空间,则f∶X→Y是基-可数中紧映射.(iii)设f∶X→Y是Lindelf闭映射,若Y为正则的基-可数中紧空间,X为正则空间,并且ω(X)≥ω(Y),则X为基-可数中紧空间. 展开更多
关键词 中紧 -可数中紧 -仿紧映射 -可数中紧映射
下载PDF
基-meso紧空间的若干性质
7
作者 耿妮 张玮琳 +1 位作者 王宪 周兴 《佳木斯大学学报(自然科学版)》 CAS 2013年第1期142-143,146,共3页
着重证明了:(1)设X是meso紧空间,X=∪i∈NFi,Fi为相对于X的基-meso紧闭子集,则X是基-meso紧的.(2)X是基-meso紧空间,若MX是Fσ集,且ω(M)=ω(X),则M为基-meso紧空间的.(3)设f:X→Y是基-meso紧映射,ω(X)≥ω(Y),如果Y是正规的基-meso... 着重证明了:(1)设X是meso紧空间,X=∪i∈NFi,Fi为相对于X的基-meso紧闭子集,则X是基-meso紧的.(2)X是基-meso紧空间,若MX是Fσ集,且ω(M)=ω(X),则M为基-meso紧空间的.(3)设f:X→Y是基-meso紧映射,ω(X)≥ω(Y),如果Y是正规的基-meso紧空间,那么X是基-meso紧空间. 展开更多
关键词 紧有限 -meso紧 -meso紧映射
下载PDF
基-可数亚紧空间
8
作者 唐永帅 高绍娟 康素玲 《四川理工学院学报(自然科学版)》 CAS 2011年第4期399-401,共3页
文章引入了基-可数亚紧空间,获得了如下主要结果:(1){Fi}i∈N是空间X的点有限闭覆盖,每一闭集Fi(i∈N)是相对于X的基-可数亚紧闭子空间,则X是基-可数亚紧空间。(2)设f:X→Y是基-可数亚紧映射,ω(X)≥ω(Y),如果Y是正则的基-可数亚紧空间... 文章引入了基-可数亚紧空间,获得了如下主要结果:(1){Fi}i∈N是空间X的点有限闭覆盖,每一闭集Fi(i∈N)是相对于X的基-可数亚紧闭子空间,则X是基-可数亚紧空间。(2)设f:X→Y是基-可数亚紧映射,ω(X)≥ω(Y),如果Y是正则的基-可数亚紧空间,那么X是基-可数亚紧空间。 展开更多
关键词 点有限 -可数亚紧空间 -可数亚紧映射
下载PDF
基—可数次亚紧空间
9
作者 王宪 周兴 耿妮 《四川理工学院学报(自然科学版)》 CAS 2012年第6期86-88,共3页
引入了基-可数次亚紧空间,获得了如下主要结果:(1){Fi}i∈N是空间X的闭覆盖,每一闭集Fi(i∈N)是相对于X的基-可数次亚紧闭子空间,则X是基-可数次亚紧空间。(2)设f:X→Y是基-可数次亚紧映射,ω(X)≥ω(Y),如果Y是正则的基-可数次亚紧空间... 引入了基-可数次亚紧空间,获得了如下主要结果:(1){Fi}i∈N是空间X的闭覆盖,每一闭集Fi(i∈N)是相对于X的基-可数次亚紧闭子空间,则X是基-可数次亚紧空间。(2)设f:X→Y是基-可数次亚紧映射,ω(X)≥ω(Y),如果Y是正则的基-可数次亚紧空间,那么X是基-可数次亚紧空间。 展开更多
关键词 -可数次亚紧空间 -可数次亚紧映射
下载PDF
基-可次数仿紧空间
10
作者 周兴 王宪 孙文 《四川理工学院学报(自然科学版)》 CAS 2013年第2期98-100,共3页
文章研究基-可数次仿紧空间,得出:①如果{Fi}i∈N是空间X的一个δ-离散闭覆盖,对于任意一个相对于X的闭集Fi(i∈N)是闭的基-可数次仿紧子空间,则称X是基-可数次仿紧空间;②令g:X→Y是基-可数次仿紧的一个映射,ω(X)≥ω(Y),若Y是基-可... 文章研究基-可数次仿紧空间,得出:①如果{Fi}i∈N是空间X的一个δ-离散闭覆盖,对于任意一个相对于X的闭集Fi(i∈N)是闭的基-可数次仿紧子空间,则称X是基-可数次仿紧空间;②令g:X→Y是基-可数次仿紧的一个映射,ω(X)≥ω(Y),若Y是基-可数次仿紧空间并且是正则的,则X是基-可数次仿紧空间。将拓扑空间的仿紧性质的一个结果推广到拓扑空间的次仿紧性质领域,使得关于拓扑空间的次仿紧性质应用起来更方便,该结果使得次仿紧性质和仿紧性质之间的关系更加清楚。 展开更多
关键词 闭空间 一可数次仿紧映射 艿一离散空间 -可数次仿紧空间
下载PDF
模糊化拟阵的最新进展 被引量:1
11
作者 史福贵 修振宇 《聊城大学学报(自然科学版)》 2015年第2期1-11,共11页
本文拟对模糊化拟阵理论做一个简短的介绍和评述,试图使读者了解模糊化拟阵理论的最新研究成果.
关键词 模糊化拟阵 模糊化次模函数 基映射 映射 模糊化幼阵 模糊化对偶 模糊化自由积
下载PDF
Cardinal Numbers of Fuzzy Sets 被引量:8
12
作者 李洪兴 罗承忠 +1 位作者 汪培庄 袁学海 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第3期101-107,共7页
Up to now, the study on the cardinal number of fuzzy sets has advanced at on pace since it is very hard to give it an appropriate definition. Althrough for it in [1], it is with some harsh terms and is not reasonable ... Up to now, the study on the cardinal number of fuzzy sets has advanced at on pace since it is very hard to give it an appropriate definition. Althrough for it in [1], it is with some harsh terms and is not reasonable as we point out in this paper. In the paper, we give a general definition of fuzzy cardinal numbers. Based on this definition, we not only obtain a large part of results with re spect to cardinal numbers, but also give a few of new properties of fuzzy cardinal numbers. 展开更多
关键词 Fuzzy relations Fuzzy mappings the cardinal numbers of fuzzy sets
下载PDF
关于相对拓扑压的一个注记
13
作者 张强 历智明 王延庚 《西北大学学报(自然科学版)》 CAS CSCD 北大核心 2015年第2期186-192,共7页
通过引入映射的基的概念,运用分离集在非紧系统中定义并研究了相对拓扑压,给出了相对拓扑压的若干基本性质,并且证明了相对拓扑压是一致拓扑共轭下的不变量。
关键词 映射 非紧系统 相对拓扑压 一致拓扑共轭
下载PDF
Spaces with σ-locally Countable Weak Bases
14
作者 夏省祥 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第2期37-41,共5页
In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to A... In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to Alexandroff’s problems. 展开更多
关键词 msss_mapping sequence_covering mapping cs_network weak base
下载PDF
Ontology mapping approach based on set & relation theory and OCL 被引量:1
15
作者 钱鹏飞 张申生 刘英华 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第4期498-504,共7页
An ontology mapping approach based on set & relation theory and OCL is introduced,then an ontology mapping meta-model is established which is composed of ontology related elements,mapping related elements and defi... An ontology mapping approach based on set & relation theory and OCL is introduced,then an ontology mapping meta-model is established which is composed of ontology related elements,mapping related elements and definition rule related elements.This ontology mapping meta-model can be regarded as a unified mechanism to realize different kinds of ontology mappings.The powerful computation capability of set and relation theory and the flexible expressive capability of OCL can be used in the computation of ontology mapping meta-model to realize the unified mapping among different ontology models.Based on the mapping meta-model,a general mapping management framework is developed to provide a common mapping storage mechanism,some mapping APIs and mapping rule APIs. 展开更多
关键词 ONTOLOGY mapping meta-model set and relation theory OCL mapping management
下载PDF
A MODIS Time Series Data Based Algorithm for Mapping Forest Fire Burned Area 被引量:4
16
作者 YANG Wei ZHANG Shuwen +3 位作者 TANG Junmei BU Kun YANG Jiuchun CHANG Liping 《Chinese Geographical Science》 SCIE CSCD 2013年第3期344-352,共9页
Burned area mapping is an essential step in the forest fire research to investigate the relationship between forest fire and cli- mate change and the effect of forest fire on carbon budgets. This study proposed an alg... Burned area mapping is an essential step in the forest fire research to investigate the relationship between forest fire and cli- mate change and the effect of forest fire on carbon budgets. This study proposed an algorithm to map forest fire burned area using the Moderate-Resolution Imaging Spectroradiameter (MODIS) time series data in Heilongjiang Province, China. The algorithm is divided into two steps: Firstly, the 'core' pixels were extracted to represent the most possible burned pixels based on the comparison of the tem- poral change of Global Environmental Monitoring Index (GEMI), Burned Area Index (BAI) and MODIS active fire products between pre- and post-fires. Secondly, a 15-km distance was set to extract the entire burned areas near the 'core' pixels as more relaxed conditions were used to identify the fire pixels for reducing the omission error as much as possible. The algorithm comprehensively considered the thermal characteristics and the spectral change between pre- and post-fires, which are represented by the MODIS fire products and the spectral index, respectively. Tahe, Mohe and Huma counties of Heilongjiang Province, China were chosen as the study area for burned area mapping and a time series of burned maps were produced from 2000 to 2011. The results show that the algorithm can extract burned areas more accurately with the hiehest accuracy of 96.61%. 展开更多
关键词 Burned area mapping Moderate Resolution Imaging Spectroradiameter (MODIS) Global Environmental Monitoring Index(GEMI) Burned Area Index (BAI)
下载PDF
The Pointwise Characterizations of Fuzzy Mappings and Fuzzy Cardinal Numbers 被引量:2
17
作者 张诚一 党平安 《Chinese Quarterly Journal of Mathematics》 CSCD 1999年第1期78-81, ,共4页
In this paper,the pointwise characterizations of fuzzy mappings are given. Based of this definition,we give a few of new properties of fuzzy cardinal numbers.
关键词 Fuzzy mappings the cardinal numbers of fuzzy sets
下载PDF
Configurable ontology mapping based on multi-feature 被引量:1
18
作者 钱鹏飞 王英林 张申生 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第6期781-788,共8页
A configurable ontology mapping approach based on different kinds of concept feature information is introduced in this paper. In this approach, ontology concept feature information is classified as five kinds, which r... A configurable ontology mapping approach based on different kinds of concept feature information is introduced in this paper. In this approach, ontology concept feature information is classified as five kinds, which respectively corresponds to five kinds of concept similarity computation methods. Many existing ontology mapping approaches have adopted the multi-feature reasoning, whereas not all feature information can be com- puted in the real ontology mapping and only fractional feature information needs to be selected in the mapping computation. Consequently a eonfigurable ontology mapping model is introduced, which is composed of CMT model, SMT model and related transformation model. Through the configurable model, users can conveniently select the most suitable features and configure the suitable weights. Simultaneously, a related 3-step ontology mapping approach is also introduced. Associated with the traditional name and instance learner-based ontology mapping approach, this approach is evaluated by an ontology mapping application example. 展开更多
关键词 ontology mapping CONFIGURABLE concept feature
下载PDF
Implementation technology of Kirchhoff demigration 被引量:1
19
作者 XU Yangyang SUN Jianguo +3 位作者 SUN Hui SUN Huiqiu JIANG Panpan ZHAO Sihang 《Global Geology》 2015年第4期252-257,共6页
Demigration refers to directly applying a specific imaging technique to a migrated section. It is applied primarily to seismic data mapping. In a previous research study, a time-efficient implementation technology of ... Demigration refers to directly applying a specific imaging technique to a migrated section. It is applied primarily to seismic data mapping. In a previous research study, a time-efficient implementation technology of demigration was expounded. In the present study, the Fast Marching Method (FMM) used for traveltime computation in the isochrone-staek demigration, is developed. Furthermore, other key techniques ( such as selection of aperture and antialiasing filtering factor) are analyzed in detail. Besides, the detail implementation method and program flow are given, which is shown their good computational efficiency and high-quality demi- gration effect. This implementation technique is illustrated with both the V(z) model and Marmousi model. It provides a basic method for implementing demigration in the application of seismic data mapping. 展开更多
关键词 DEMIGRATION travel-time computation APERTURE antialiasing
下载PDF
AN IMPROVED RADIAL BASIS FUNCTION BASED METHOD FOR IMAGE WARPING
20
作者 NieXuan ZhaoRongchun +1 位作者 ZhangCheng ZhangXiaoyan 《Journal of Electronics(China)》 2005年第4期422-426,共5页
A new image warping method is proposed in this letter, which can warp a given image by some manual defined features. Based on the radial basis interpolation function algorithm, the proposed method can transform the or... A new image warping method is proposed in this letter, which can warp a given image by some manual defined features. Based on the radial basis interpolation function algorithm, the proposed method can transform the original optimized problem into nonsingular linear problem by adding one-order term and affine differentiable condition. This linear system can get the steady unique solution by choosing suitable kernel function. Furthermore, the proposed method demonstrates how to set up the radial basis function in the target image so as to achieve supports to adopt the backward re-sampling technology accordingly which could gain the very slippery warping image. Theexperimental result shows that the proposed method can implement smooth and gradual image warping with multi-anchor points' accurate interpolation. 展开更多
关键词 Image warping Radial basis function Pixel mapping Affine map
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部