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1.
设H是一实Hilbert空间,首先给出了H空间中的一个变分不等式问题,由变分不等式与投影间的关系(张石生.变分不等式和相补问题理论及应用.上海:科学技术文献出版社,1991.)将变分不等式问题化为一个有关投影的问题,然后给出了在H空间中的一个带误差的三步投影方法.最后将该三步投影方法应用于求解变分不等式问题,给出了此方法在变分不等式中的应用.  相似文献   

2.
极小化问题可以转化为变分不等式,因此,变分不等式是解决极小化问题的一类重要方法.当变分不等式模型中的集合无界时,许多学者研究了各种各样的强制条件,以保证变分不等式的解存在.比较了几种主要强制性条件之间的关系,并在映射具有变分不等式性质时,给出了广义变分不等式解存在的证明,并且用Tikhonov正则化方法解决了不适定广义变分不等式解的存在性问题.广义混合变分不等式是比广义变分不等式更一般的模型,将广义变分不等式的Tikhonov正则化方法推广到广义混合变分不等式,以使Tikhonov正则化方法具有更加广泛的应用范围.为此,主要建立广义混合变分不等式的Tikhonov正则化理论.首先,在更弱的强制条件下,证明了广义混合变分不等式解的存在性,然后给出了广义混合变分不等式的Tikhonov正则化结果.  相似文献   

3.
首先在Banach空间中给出了分离变分不等式的Levitin-Polyak-α适定性的概念.然后讨论了分离变分不等式解集的等价表述.最后,给出了分离变分不等式的Levitin-Polyak-α适定性的Furi-Vignoli型度量刻画.  相似文献   

4.
在本文中,我们引入和研究了一类新的变分不等式.给出了找这种类型变分不等式解的算法,并讨论了这类变分不等式的几种特殊情况.  相似文献   

5.
文章定义了四种集值变分不等式组,即分别具有强解和弱解的集值向量变分不等式组和集值数量化变分不等式组。通过运用Konnov的数量化方法,研究将一个集值向量变分不等式组转化为一个集值数量化变分不等式组,并给出了两种集值变分不等式组的等价条件。  相似文献   

6.
首先在Banach空间中给出了半变分不等式(HVI)的Levitin-Polyak适定性的概念.然后,给出了半变分不等式的Levitin-Polyak适定性的度量刻画.最后,讨论了半变分不等式HVI(A,f,j,K)的Levitin-Polyak适定性和该半变分不等式的gap函数所确定的优化问题的Levitin-Polyak适定性之间的关系.  相似文献   

7.
研究了实可分自反Banach 空间中的广义随机混合似变分不等式问题,经典变分不等式及其各种各样的推广,都是这种变分不等式问题的特例.利用随机算子和Hanson 的技巧给出了这类广义随机混合似变分不等式问题的解  相似文献   

8.
利用狄尼下导数,构造了一类关于Stampacchia变分不等式的间隙函数,并在此基础上对Stampacchia变分不等式和Minty变分不等式问题的解集的性质进行讨论,给出了一些重要的结论.  相似文献   

9.
利用狄尼下导数,构造了一类关于Stampacchia变分不等式的间隙函数,并在此基础上对Stampacchia变分不等式和Minty变分不等式问题的解集的性质进行讨论,给出了一些重要的结论.  相似文献   

10.
介绍和考虑了一类新的非凸变分不等式,这类变分不等式包括了一些已知的和新的非凸变分不等式作为特例.利用一致r-近似正规集的概念,建立了这类变分不等式和不动点问题的等价关系.利用该等价关系,给出了一个求解此类非凸变分不等式的近似点算法,并证明了该算法在适当的条件下收敛.  相似文献   

11.
N Itoh  K Obata  N Yanaihara  H Okamoto 《Nature》1983,304(5926):547-549
Vasoactive intestinal polypeptide (VIP), a 28-amino acid peptide originally isolated from porcine duodenum, is present not only in gastrointestinal tissues but also in neural tissues, possibly as a neurotransmitter, and exhibits a wide range of biological actions (for example, relaxation of smooth muscle, stimulation of intestinal water and electrolyte secretion and release of insulin, glucagon and several anterior pituitary hormones). As the structure of porcine and bovine VIP shows several similarities to those of mammalian glucagon, secretin and gastric inhibitory peptide (GIP), VIP is considered to be a member of the glucagon-secretin family. Recently, we have found that VIP is synthesized from a precursor, pro-VIP (molecular weight (Mr) 17,500), in human neuroblastoma cells and that the primary translation product of the mRNA encoding VIP is prepro-VIP (Mr 20,000). In an attempt to elucidate the primary structure of the precursor, we have now cloned the DNA sequence complementary to the mRNA coding for human VIP and analysed the nucleotide sequence. The entire amino acid sequence of the precursor, deduced from the nucleotide sequence, indicates that the precursor protein contains not only VIP but also a novel peptide of 27 amino acids. The peptide, designated PHM-27, differs by only 2 amino acids from PHI-27, a peptide recently isolated from porcine intestine, and is also closely related in sequence to VIP.  相似文献   

12.
A Giachetti  S I Said 《Nature》1979,281(5732):574-575
Dense plexuses of neurones containing immunoreactive vasoactive intestinal peptide (VIP) have been found in discrete areas of the central nervous system and in peripheral organs, including the gastrointestinal tract, pancreas and urogenital system. In many of these locations VIP is concentrated in nerve endings, where it can be released by high K+ concentrations in a Ca2+-dependent manner. VIP release may also be provoked by electrical stimulation of nerves, for example the vagus. VIP thus shows some of the features of neurotransmitter or neuromodulator substances. The presence of immunoreactive VIP in the fine terminal varicosities as well as in the cell bodies of neurones suggests that it might be transported from the perikaryon, where it is presumably formed, to the nerve endings, through the axonal transport system. Such transport would be in keeping with a role for the peptide as a neurohumor or neurohormone. We report here that VIP accumulates in constricted rat sciatic nerves in a manner suggesting fast, anterograde axonal flow.  相似文献   

13.
命名数据网络(named data networking,NDN)是信息中心网络(information centric network,ICN)的一个典型实例,是未来网络一种可能的架构.为优化NDN的转发性能,要求转发平面能根据不同的网络环境自适应地调整转发策略、选出最优的转发接口.“虚拟兴趣分组”(virtual interest packet,VIP)架构是一种基于NDN的联合动态转发与缓存的网络架构,通过VIP架构对转发方案进行了性能优化.VIP架构的转发方案使用了背压算法,该算法在网络处于轻负载状态时时延较大,为此引入偏差函数进行优化.为检测优化效果,对原始VIP架构和优化后的VIP架构的转发性能进行了仿真实验对比.实验结果显示,优化后的转发方案相比原方案在转发时延上有一定降低.且由于偏差函数的引入不会增加原转发方案的时间复杂度,因此提出的方法可以优化VIP转发方案的性能.  相似文献   

14.
从人的胎脑cDNA文库中克隆到一条犬凝集素基因VIP36的人类同源基因,此cDNA序列全长2430bp,拟编码一个382个氨基酸残基的蛋白,它编码的蛋白与犬VIP36有52%的同源性,因此将其命名为人类VIP36L基因,应用辐射杂交方法,钭该基因定位在人2号染色体的分子标记D2S388和D2S113之间,采用基因芯片杂交的方法研究其表达谱情况,发现该基因在胎皮和肝癌组织中表达量较高。  相似文献   

15.
考虑了单调变分不等式的一种扰动,通过扰动变单调不等式为强单调变分不等式.利用广义的D-间隙函数提出一种无需计算函数梯度的算法,进一步证明此算法产生的每一聚点都是原变分不等式的解.  相似文献   

16.
Tzfira T  Vaidya M  Citovsky V 《Nature》2004,431(7004):87-92
Genetic transformation of plant cells by Agrobacterium represents a unique case of trans-kingdom DNA transfer. During this process, Agrobacterium exports its transferred (T) DNA and several virulence (Vir) proteins into the host cell, within which T-DNA nuclear import is mediated by VirD2 (ref. 3) and VirE2 (ref. 4) and their host cell interactors AtKAP-alpha and VIP1 (ref. 6), whereas its integration is mediated mainly by host cell proteins. The factors involved in the uncoating of T-DNA from its cognate proteins, which occurs before integration into the host genome, are still unknown. Here, we report that VirF-one of the few known exported Vir proteins whose function in the host cell remains unknown-is involved in targeted proteolysis of VIP1 and VirE2. We show that VirF localizes to the plant cell nucleus and interacts with VIP1, a nuclear protein. VirF, which contains an F-box motif, significantly destabilizes both VIP1 and VirE2 in yeast cells. Destabilization of VIP1 in the presence of VirF was then confirmed in planta. These results suggest that VIP1 and its cognate VirE2 are specifically targeted by the VirF-containing Skp1-Cdc53-cullin-F-box complex for proteolysis. The critical role of proteasomal degradation in Agrobacterium-mediated genetic transformation was also evident from inhibition of T-DNA expression by a proteasomal inhibitor.  相似文献   

17.
J McCulloch  P A Kelly 《Nature》1983,304(5925):438-440
Vasoactive intestinal polypeptide (VIP) is present in high concentrations in the cerebral cortex, where it is the putative neurotransmitter of a major intracortical neuronal system. Homogenates of cortical tissue contain high-affinity, specific binding sites for VIP as well as an adenylate cyclase system which is sensitive to this peptide. As with many of the other peptidergic systems which have been identified in the central nervous system (CNS), it has proved extremely difficult to elucidate the nature and extent of the functional role of VIP in specific brain areas. Here, using the quantitative autoradiographic 14C-deoxyglucose technique in rats to provide insight into functional processes, we describe the increases in glucose utilization which occur locally in anterior cingulate cortex following the unilateral injection of VIP (20 pmol) into this key brain area and, additionally, the focal alterations in glucose use in CNS regions having known neuronal connections with the injected region (for example, ipsilateral mediodorsal thalamus, ventral tegmental area, nucleus accumbens, caudate nucleus and contralateral cingulate cortex). These data provide evidence that VIP may modify the processing of afferent and efferent information within the anterior cingulate cortex in the conscious rat.  相似文献   

18.
70只35日龄SPF鸡随机分成对照组和攻毒组.攻毒组经腹腔接种鸡新城疫病毒后,分别取腺胃,并用免疫组织化学方法检测组织中NDV、P物质和VIP的分布及动态变化.结果表明:P物质和VIP在两组鸡的腺胃中都有存在,且三种物质的表达量呈现正相关性,其含量在感染后有增加,证明了P物质和VIP在感染NDV后有调节动物防御系统的作用.  相似文献   

19.
交通线路要人安保是大型政治活动及重要外事活动安保任务的重要组成部分,其重要性非同小可。随着社会经济高速发展,要人安保工作面临的风险与挑战与日俱增,传统的依靠全警力投入与全交通封闭管制模式,不仅造成警力及社会资源浪费,且无法保证安保对象绝对安全。从技术视角,结合武汉第七届世界军人运动会智慧交通线路警卫安保系统的成功运用效果,阐述如何运用信息化手段进行交通线路要人安保,重点论述北斗高精定位与智能视频接力技术在要人安保中的创新应用,并结合要人安保实际需求进行关键技术设计研发,实现智慧化精细化交通线路要人安保。  相似文献   

20.
应用EndNote和维普期刊库实现中文文献管理   总被引:6,自引:0,他引:6  
维普期刊库是中国最大的文献数据库之一,EndNote是美国ISI开发的科研文献管理软件。通过设计制作格式转换软件和导入模板,将从维普期刊网上检索获得的中文文献导入EndNote,构建了个人中文文献数据库;同时设计制作了符合中文学术论文参考文献格式要求的word格式模板,用于学术论文的撰写,以提高论文的写作效率。  相似文献   

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