首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
On current network actuality and development trend, it is necessary to put traffic engineering in practice in IP backbone network on IP/MPLS. The essential demand in actualizing traffic engineering is traffic matrix measurement. After analyzing the defect of current measurement method, traffic engineering model and traffic matrix on LSP in IP backbone network based on MPLS, or relevant routing algorithm are researched. The merit of the traffic matrix's measurement method is that implement of measurement is only located in the edge node; therefore, network resource's cost is lower and it offers a new train of thoughts for resolving the flaw of current main measurement methods, moreover, and condition for actualizing traffic engineering.  相似文献   

2.
Nowadays the network of high-speed and broadband is required in the application of multimedia technology and information community. Many methods, such as network layering design, address design and routing are introduced to design Enterprise Backbone Network VPN's interrelation protocol is disposed and VPN tunnel is cut to establish virtual private network. Server and run plane design, bowels IP address distribution and network security advisement to design Intelligent Residential Area Network are given. It is pointed out that the method of modern network designs satisfies high-speed, intelligent and broadband for the developments of network technology.  相似文献   

3.
According to the simulation results, the factors causing the forming of self-similarity in IP network is presented. Through analysis based on ON/OFF model, we show the influence of traffic source integration level on self-similarity degree. Using the above results, an IP network traffic generator is implemented. Tests in real environment show that the generator can better reflect the relationship of file sizes, protocol types, ON/OFF residence time, traffic source integration levels and self-similarity degrees.  相似文献   

4.
5.
How to make use of computer network in teaching becomes the focus of concern for the computer engineers and teachers.The remote video consultation classroom can be used in teaching by using internet and NGN server to improve the instruction and stimulate the students' interest in study.As the IP network is widely used in campus,connection could be set up for student dormitory,office or even the teacher's home.On the computer network teacher and student can discuss face to face online and make best use of their time.This paper discusses the problem about how to construct a network-video class room based on computer network including VOIP and NGN(new generation network) switch server.  相似文献   

6.
VPN is a technology that realizes the security transmission of private information through the public network. As one of key technologies, tunnel technology resolves the mobility problem of mobile nodes. Firstly, L2TP and IPSec have been compared based on these two tunnel principles introduction of VPN. Secondly the advantages of IPSec in security have been introduced. Then, the problems of mobile host and two models of tunnel in VPN have been introduced. Lastly, the advantages of utilizing the mobile IP to resolve the problem of mobile host have been analyzed, and this technology has been compared with VPDN.  相似文献   

7.
The response of a wide range of Brassica juncea accessions to 14 isolates of Peronospora parasitica, 12 from India (IP00A, IP02, IP03, IP04, IP04A, IP05, IP05B, IP33 and IP33A were derived from B. juncea; IP09, IP14 and IP13A from B. rapa) and two from B. napus in the UK (R1 and P003), was screened. Sixteen differential host response groups to these isolates (classified as groups A‐P) were identified. Groups‘A’and‘B’expressed the widest resistance profiles to these isolates. Group‘A’was susceptible to isolates IP05 and IP05B, moderately resistant to isolate IP33 and resistant to all other isolates. Group‘B’was susceptible to isolates IP03, IP04 and IP04A, and resistant to the other isolates. Putative homozygous lines resistant to all 14 isolates were selected from the F4 progeny of crosses involving lines RESBJ‐200 from group‘A’(selection from cv. Kranti) and RESBJ‐190 from group‘B’(selection from cv. Krishna). Both selections were selfed and tested for uniformity of reactions to all isolates for three generations. The resistance of RESBJ‐200 to isolates IP00A, IP04A and IP33A seems to be conditioned by single dominant genes. The resistance of RESBJ‐190 to isolates IP00A, IP05B and IP33A was also conditioned by single dominant genes. The gene for resistance to IP00A and IP33A in RESBJ‐200 seems to be independent of the genes for resistance to the same isolates in RESBJ‐190. The new genes for differential resistance to P. parasitica will be of value in future studies of the genetics of the host‐pathogen interaction and for breeding for disease resistance.  相似文献   

8.
基于ISSR和AFLP标记开发甜菜 SSR 引物的研究   总被引:1,自引:1,他引:0  
本研究以ISSR-PCR和AFLP标记原理为基础,介绍一种新的分离甜菜基因组微卫星引物的方法。首先对甜菜基因组DNA进行酶切并连接已知序列的接头,构建基因组DNA酶切文库,同时用一个或两个ISSR引物,扩增文库中两端含微卫星序列片段并进行克隆测序,根据测序结果设计微卫星序列间的IP1引物和IP1与微卫星序列间IP2 引物;再根据侧翼序列克隆原理,采用巢式PCR进行基因组步移,扩增IP2引物下游序列,根据巢式PCR产物测序结果,设计微卫星序列另一侧的引物IP3 ,IP2和IP3即为SSR标记引物,对获得的SSR引物进行PCR验证,结果表明SSR引物产率为16%,本研究获得的SSR引物具有较高的多态性,对于后续的遗传多样性检测和遗传连锁图构建具有重要意义。  相似文献   

9.
Previous studies showed that the yellow seed color gene of a yellow mustard was located on the A09 chromosome. In this study, the sequences of the molecular markers linked to the yellow seed color gene were analyzed, the gene was primarily mapped to an interval of 23.304 to 29.402M. Twenty genes and eight markers’ sequences in this region were selected to design the IP and SCAR primers. These primers were used to screen a BC8S1 population consisting of 1256 individuals. As a result, five IP and five SCAR markers were successfully developed. IP4 and Y1 were located on either side of the yellow seed color gene at a distance of 0.1 and 0.3 cM, respectively. IP1, IP2 and IP3 derived from Bra036827, Bra036828, Bra036829 separately, co-segregated with the target gene. BLAST analysis indicated that the sequences of newly developed markers showed good collinearity with those of the A09 chromosome, and that the target gene might exist between 27.079 and 27.616M. In light of annotations of the genes in this region, only Bra036828 is associated with flavonoid biosynthesis. This gene has high similarity with the TRANSPARENT TESTA6 gene, Bra036828 was hence identified as being the gene possibly responsible for yellow seed color, in our research.  相似文献   

10.
In this paper, the encapsulation of ICMP packets and the specifications of IP packet, ICMP packet and UDP packet are introduced. At the angle of the protocol analysis, a ICMP attack case is described the characters of attack are abtained and the corresponding countermeasures are presented.  相似文献   

11.
为了研究池塘流水槽循环水黑鲷养殖模式(IP)和传统池塘黑鲷养殖模式(EP)菌群结构特征,运用高通量测序技术,比较分析2种养殖模式黑鲷肠道和养殖水体中菌群组成结构与功能。结果显示:黑鲷肠道和养殖水体中主要由变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、蓝藻细菌(Cyanobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)和绿弯菌门(Chloroflexi)组成,其丰度之和为98.32%~99.22%;在属水平上,菌属差异明显,IP模式下黑鲷肠道显著增加的菌属包括鲁杰氏菌属Ruegeria(14.84%)、聚球藻属Synechococcus(14.24%)、Marivita(3.58%)、norank_o__PeM15(2.97%)、norank_C__KD4-96(2.56%)(P<0.05) (IP>EP);而EP模式下,黑鲷肠道中肠杆菌属Enterobacter(10.31%)、分支杆菌属Mycobacterium(10.30%)、Romboutsia(7.37%)、肠球菌属Enterococcus(6.29%)、乳球菌属Lactococcus(5.38%)显著增加(P<0.05) (IPP<0.05);IP养殖模式水体菌群丰富度和多样性显著高于EP养殖模式(P<0.05),而黑鲷肠道之间无显著性差异(P>0.05)。2种养殖模式条件下菌群结构存在差异,且存在较多丰度差异显著的菌属。IP模式下黑鲷肠道中具有差异显著的优势菌属大多为有益菌,而EP模式黑鲷肠道多为慢性致病菌或条件致病菌属。  相似文献   

12.
J. R. Baggett 《Euphytica》1978,27(2):593-599
Summary Internal anthocyanin pigmentation (IP) in otherwise normally green cabbage occurs in a number of Oregon State University breeding lines. Extracted pigment, tested for spectral absorption and for color reactions with lead acetate and aluminium chloride, was similar but not necessarily identical to pigment extracted from red cabbage cultivar Redman. When IP line R52 was crossed with normal green line C70, the F1, F2 and backcross progenies indicated that IP at the intensity found in R52 was determined by a single factor in homozygous condition, with intermediate levels of IP expressed by the heterozygous genotypes. Modifying factors also appear to influence the level of IP. In the cross R52 (IP)×R51 (normal green), expression of IP in the F1 was much reduced. The F2 failed to fit the expected 3 IP: 1 green ratio due to an excess of green plants, but instead, closely fit a 9:7 ratio. This may have resulted from incomplete expression of IP because of modifiers, rather than from the effects of a second major gene. An allele at the A (anthocyanin) locus of B. oleracea is tentatively proposed and designated A IP or a IP pending further identification.Oregon Agricultural Experiment Station Technical Paper No. 4690.  相似文献   

13.
In accordance with the requirements of industrial mechanical vibration field data real-time transmission in the condition of multi-survey-point and mass data acquisition, an Ethernet data transmission method based on Ethernet controller RTL8019AS and TMS320C5402 DSP is presented. Packing data from A/D into UDP and IP package and controlling RTL8019AS through I/O mapped registers, high-speed DSP makes real-time communication high performance. Ethernet frame protocol and TCP/IP protocol are simplified for the specific purpose. And the interface technology between Ethernet controller RTL8019AS and DSP is solved. The system evaluation and debugging are made.  相似文献   

14.
In this paper, the temperature field, stress, critical crack size and expenditure rate of life of HP and IP rotors of 200MW Chinese-built steam turbines in eight typital patterns of cold start of Chongqing Power Plant was calculated by finite element method. Some problems in speed-up process have been discussed, and advanced that it is better to appraise start-up process by Fracture Mechanics Mechod in the period when the temperature of rotor is low. The discussion are useful for the start of steam turbines.  相似文献   

15.
The intensity and efficiency are two centrally technical indicator of the firewall. The function of state checking of network's fire wall is to check the coming data pack, to judge if those connected entities are accordant with the rule of TCP/IP exchange. Attacks of DoS/DDoS send large numbers of short data packs to firewall in a short time. Those attacks may make firewall's iptables overflow and refuse new connection. The traditional solutions often increase the burden of the firewall. This paper puts a new temporary way to solution this problem in emergent state.  相似文献   

16.
RS-232 serial communication has to be adopted in the communication between computers and some equipments without TCP/IP enclosed. First, the main properties and events of MSCOMM32.ocx component are discussed in this paper. And then we expatiate on the method of using the MSCOMM32.ocx component to obtain serial communication under Delphi environment via a real application example of Telecommunication industry. In the mean time the designing framework implementing the serial communication is presented. At last we discuss the problems that should be considered in the communication control program.  相似文献   

17.
稻田套播和氮素对中筋小麦产量和品质的调节效应   总被引:1,自引:0,他引:1  
采用稻田套播与传统条播两种栽培方式系统比较的方法,研究不同氮肥运筹下稻田套播方式对中筋小麦扬麦10号籽粒产量和品质的调节效应。结果表明:稻田套播方式对中筋小麦籽粒产量和品质影响显著。与传统条播方式相比,在同一氮肥运筹下套播方式中筋小麦除籽粒总淀粉及其组分含量显著高于条播方式外,籽粒产量、蛋白质含量、蛋白质产量、磨粉品质和面粉品质以及淀粉糊化特性的主要指标低于传统条播,且差异显著。稻田套播方式不利于中筋小麦扬麦10号优质的形成,在江苏淮南地区中筋专用小麦采用稻田套播方式宜适当增加施氮量且追氮适度后移。  相似文献   

18.
为了验证外源性Ca2+影响沉积物中制约初级生产的生物活性磷的赋存形态的科学假说,在充气的条件下,将沉积物暴露于不同浓度的外源性Ca2+ 30天,测定并分析其生物活性磷的赋存形态的差异。浓度0、50、200、500 mg/L的外源性Ca2+暴露下的表层沉积物Ex-P含量为0.08±0.02、0.05±0.00、0.05±0.01、0.06±0.01 μmol/g,50 mg/L的外源性Ca2+暴露下的表层沉积物Ex-P含量低于0 mg/L的外源性Ca2+暴露下的(P<0.05);相同浓度外源性Ca2+暴露下的表层沉积物IP含量为0.37±0.10、0.46±0.16、0.41±0.06和0.69±0.05 μmol/g,0 mg/L的外源性Ca2+暴露下的表层沉积物的IP含量低于500 mg/L的外源性Ca2+暴露下的(P<0.05);底层沉积物Ex-P和IP含量不受外源性Ca2+的影响。故外源性Ca2+影响表层沉积物中生物活性磷含量,对沉积物Ex-P含量有双重阈值作用,并可将水体中的磷转化为可以缓释的沉积物磷。  相似文献   

19.
基于深度卷积神经网络的玉米病害识别   总被引:8,自引:2,他引:6  
为了提高玉米病害的识别率,本文提出了一种在自然环境条件下基于深度卷积神经网络的玉米病害识别方法。该方法以玉米常见的10类病害为研究对象。算法模型是先将图像预处理,应用Triplet loss双卷积神经网络结构学习玉米图像特征,再使用SIFT算法提取图像纹理细节,最后通过Softmax对图像进行标签分类。训练集采用正常玉米图像与玉米病害图像相结合的方式,使用深度相似性网络学习正常玉米图像特征表示,再使用迁移学习方法学习玉米病害图像的特征,最后对特征进行分类识别。研究结果表明,该方法可准确识别10种常见玉米病害,正确率可达90%以上,为玉米病害的防治提供了有效的技术支持。  相似文献   

20.
辽宁省松毛虫发生面积气象预报方法研究   总被引:1,自引:1,他引:0  
为了利用气象因子预测松毛虫的发生面积,基于辽宁省阜新县1983—2008年气象资料与松毛虫发生面积等资料进行相关分析,将筛选出的气象因子作为预报因子,通过多元回归法和人工神经网络法对松毛虫发生面积进行模拟和预测。结果表明,与松毛虫发生面积显著相关的5个气象因子包括:上一年12月平均最低温度、上一年11月平均相对湿度、上一年9月降水量、本年2月降水量和本年3月降水量;人工神经网络法的模拟和预测精度均优于多元回归法,多元回归法的预测精度58.2%,人工神经网络法的预测精度为83.6%;人工神经网络法更适用于辽宁地区松毛虫发生面积的预报。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号