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1.
本文在现有多活性代理复杂信息系统理论及其方法的研究基础上,进一步阐述了多活性代理理论体系的基本概念、活性代理的内涵;提出了活性度的概念、特性以及表征;基于活性度的研究,讨论了通过代理活性保持、协商协调增强信息系统的活性方法.首先,从组成复杂信息系统的集合、空间等概念出发,明确了多活性代理复杂信息系统理论体系所涉及的基本概念,以及这些基本概念之间的关系;其次,根据复杂信息系统功能层次上特点与活性自组织机理,提出了代理活性度的概念,并详细探讨了代理活性度的特性、表征及应用实例;同时,从活性的丧失、感知、调整以及判断决策等几个方面给出了多活性代理复杂信息系统活性保持策略;最后,本文详细探讨了多活性代理功能保持的协商协调机理、方法.上述研究成果进一步完善了多活性代理理论体系,并初步给出了代理活性和系统活性的定量表征表示方法,为进一步开展多活性代理复杂信息系统的理论和应用研究奠定了基础.  相似文献   

2.
Developments in the application of quantum mechanics to the understanding of the chemical bond are traced with a view to examining the evolving conception of the covalent bond. Beginning with the first quantum mechanical resolution of the apparent paradox in Lewis’s conception of a shared electron pair bond by Heitler and London, the ensuing account takes up the challenge molecular orbital theory seemed to pose to the classical conception of the bond. We will see that the threat of delocalisation can be overstated, although it is questionable whether this should be seen as reinstating the issue of the existence of the chemical bond. More salient are some recent developments in a longstanding discussion of how to understand the causal aspects of the bonding interaction—the nature of the force involved in the covalent link—which are taken up in the latter part of the paper.  相似文献   

3.
供应链网络设计决定了供应链的结构体系,也决定了供应链本身的价值。本文以供应链整体价值最大化为目标,构建网络设计决策框架,用系统的观点全面分析网络设计的影响因素与内容。引入不同市场的响应时间变量,考虑响应时间对销售收入和供应链总成本的影响,建立网络设计优化模型,并通过算例分析表明:不同市场顾客需求的响应时间对供应链价值的边际贡献存在显著差异,网络设计应从供应链整体系统出发,平衡供应链的反应能力与赢利水平。  相似文献   

4.
This paper examines the lead-lag relationship between the spot index and futures price of the Nikkei Stock Average. Using daily data in the post-crash period we investigate the interaction between the spot and futures series through the error correction model. Two versions of error correction models are considered, depending on the postulated long-run equilibrium relationship. It is found that lagged changes in the futures price affect the short-term adjustment in the spot index, but not vice versa. Forecasting models for the spot index are also constructed using the univariate time series approach and the vector autoregressive method. For the post-sample forecast comparison the error correction models produce the best results. The vector autoregressive method performs better than the martingale model, while the univariate time series method gives the poorest forecasts.  相似文献   

5.
6.
The observation of embryonic mammary glands in male and female mice under the electron microscope has shown on one hand that the cellular ultrastructure of the buds is characterized by embryonic tissue only slightly differentiated, and on the other that, under the influence of testicular hormone, the detachment of the anlage from the epidermis in fourteen-day old embryos results in an important modification in the relationship between the ectoderm and the mesenchyme at the level of the neck of the gland rudiment. The basal membrane is destroyed and numerous centers of necrosis can be seen starting from the dense bodies in the ectodermic cells of the ruptured zone.  相似文献   

7.
传统的工作流技术局限于当时的业务需求和技术水平,已不能满足当今业务过程管理的需要。企业运营过程中重要的合同审核业务流程仍由合同管理人员操作完成,浪费人力物力的同时易造成信息传递不及时、不准确,极大影响了企业运作。本文利用面向服务工作流技术解决传统工作流的局限性,并将面向服务的工作流技术应用在合同审核业务中,规范了合同审核的过程,避免了人为干预,实现了合同审核在各系统间的自动传递。  相似文献   

8.
9.
This is the second in a series of three papers that charts the history of the Lenz–Ising model (commonly called just the Ising model in the physics literature) in considerable detail, from its invention in the early 1920s to its recognition as an important tool in the study of phase transitions by the late 1960s. By focusing on the development in physicists’ perception of the model’s ability to yield physical insight—in contrast to the more technical perspective in previous historical accounts, for example, Brush (Rev Modern Phys 39: 883–893, 1967) and Hoddeson et al. (Out of the Crystal Maze. Chapters from the History of Solid-State Physics. Oxford University Press, New York, pp. 489–616, 1992)—the series aims to cover and explain in depth why this model went from relative obscurity to a prominent position in modern physics, and to examine the consequences of this change. In the present paper, which is self-contained, I deal with the development from the early 1950s to the 1960s and document that this period witnessed a major change in the perception of the model: In the 1950s it was not in the cards that the model was to become a pivotal tool of theoretical physics in the following decade. In fact, I show, based upon recollections and research papers, that many of the physicists in the 1950s interested in understanding phase transitions saw the model as irrelevant for this endeavor because it oversimplifies the nature of the microscopic constituents of the physical systems exhibiting phase transitions. However, one group, Cyril Domb’s in London, held a more positive view during this decade. To bring out the basis for their view, I analyze in detail their motivation and work. In the last part of the paper I document that the model was seen as much more physically relevant in the early 1960s and examine the development that led to this change in perception. I argue that the main factor behind the change was the realization of the surprising and striking agreement between aspects of the model, notably its critical behavior, and empirical features of the physical phenomena.  相似文献   

10.
The objectives of this study were to evaluate the effect of diet on the colonisation by Campylobacter jejuni of the chick caeca, and to determine whether the viscosity of the intestinal contents and mucin carbohydrates were altered by the diet. The diets investigated were maize based, wheat-based or wheat-based supplemented with xylanase. The xylanase-supplemented diet reduced the viscosity and lowered the numbers of Camp. jejuni. Feeding the enzyme-supplemented diet increased the amount of neutral and sulphated mucins in the goblet cells of the small and large intestines and caecum. An abundance of sulphated and carboxylated mucins was seen in the surface goblet cells of the large intestine with the maize- and wheat-based diets. Both the diet supplemented with xylanase and the maize diets increased crypt-surface glycosylation of the sialic acid residues. The analysed data from the combined sites showed significant differences in the amount of neutral and acidic mucins when comparing the wheat and the wheat plus xylanase diets. However, no changes were shown in the staining intensity of sulphated mucins between the three diets. Significant differences in the glycosylation of sialic acid and in the N-acetylglucosamine residues were shown between dietary groups. These results provide evidence that the wheat diet supplemented with xylanase leads to greater changes in the mucin composition and carbohydrate expression of goblet cell glycoconjugates, which are associated with a reduction in intestinal viscosity and decreased numbers of Camp. jejuni.  相似文献   

11.
针对批量钻削工序质量的快速监测和分析问题,利用批量钻削加工过程主轴功率信号和声信号的时域统计特征和频域能量特征构造了批量工序钻削过程特征矩阵。应用K均值聚类技术从时域统计、频域能量和时频域综合特征三个角度依据钻孔本身的质量特征对钻孔进行分类,分析批量工序过程特征分布状况,间接反映批量钻削工序质量。对比人工质量检测结果,分析批量钻削过程监控信号时频域特征矩阵聚类纯净度,结果显示其工序质量分布状况检测准确率高达94.19%  相似文献   

12.
The Smith's Prize competition was established in Cambridge in 1768 by the will of Robert Smith (1689-1768). By fostering an interest in the study of applied mathematics, the competition contributed towards the success in mathematical physics that was to become the hallmark of Cambridge mathematics during the second half of the nineteenth century. Perceptions of Smith's intentions were to play a part in discussions about the content and balance of the mathematics curriculum, as may be seen in the Airy quotation in the title. In the twentieth century the competition acted to stimulate the formalization of Cambridge postgraduate research in mathematics. Throughout its existence the competition has played a significant role by providing a springboard for graduates considering an academic career and the majority of prize-winners have gone on to become professional mathematicians or physicists. In seeking the reasons behind the competition's success, attention has been paid to the life and work of Robert Smith, the intention behind his bequest, and the history of the competition from its origins until 1940.  相似文献   

13.
运载火箭全箭动特性三维建模技术   总被引:5,自引:0,他引:5  
目前国内运载火箭动力学特性建模以梁模型为主,但梁模型是对运载火箭三维结构的一种简化,存在若干弊端.采用三维建模方法可以克服这些弊端.总结了作者近几年开展的运载火箭三维建模的研究工作,提出了运载火箭三维建模方法,包括硬壳与半硬壳结构建模方法、夹芯结构建模方法、发动机架及发动机建模方法、燃料液体建模方法、非结构质量建模方法以及连接建模方法.尤其针对液体建模,提出了燃料液体杆单元建模方法,使液体建模工作大为简化.通过工程实例应用以及和试验的对比,证明了建模方法的适用性.同时也提出了运载火箭建模当中的不确定因素.  相似文献   

14.
文中提出基于随机发送参考的多天线系统传输算法,用于保障物理层信息安全传输.该算法将授权用户的信道分解为多个独立并行的信道,并在其中的一个信道中发送随机化的导频信息,同时对其他信道加密.由于窃听方信道与授权用户不同,很难通过自身的信道分解出独立的随机化导频信道,从而无法正常解调、还原信息.通过理论分析及算法仿真表明,随机发送参考算法可使窃听方的误码率稳定在较高水平,并且在同等发送功率的情况下性能优于现有加性人工方法.  相似文献   

15.
Summary Cyclic monomers polymerizable stereospecifically can be divided into two classes: monomers in which the polymerizable double bond is situated outside the ring and those in which the polymerizable group is in the ring itself.For the first group it is shown how the ring and its substituents influence the rate, stereospecificity and the polymerization mechanism as well as the crystallizability and the crystalline structure of the tactic polymers formed.With regard to the 2nd group the possible polymerization mechanisms are indicated that can on the whole occur through cleavage of the ring or opening of the double bond, for numerous typical representatives of this class of monomers and the criteria are explained on which stereospecificity depends.  相似文献   

16.
G D Guex  P S Chen 《Experientia》1986,42(11-12):1205-1218
The intrauterine nourishment of the viviparous alpine salamander, Salamandra atra, has been demonstrated to consist of two phases: oophagy - after hatching from the jelly membrane, the developing embryo ingests the remaining disintegrated, unfertilized egg mass. Epitheliophagy - a special cranial portion of the uterus wall, the zona trophica, is stimulated by the presence of the embryo. After the yolk mass has been exhausted, the developing embryo is supplied with epithelial cells as nourishment until the end of pregnancy. The epithelial cells of the zona trophica are released into the uterus lumen by partial necrosis of the underlying connective tissue. Regeneration and detachment of the uterine epithelium occur simultaneously in different regions of the zona trophica. A special dentition enables the embryo, according to its position in the uterus, to feed directly on the zona trophica.  相似文献   

17.
M Gadea-Ciria 《Experientia》1976,32(7):889-890
Studying the effects that removal of the cerebellum and the frontal lobes had upon the phasic activities (PGO waves) of paradoxical sleep in the cat, it is shown that in this phase of the sleep-wakefulness cycle the cerebellum exerts an inhibitory action upon the amplitude of the GPO, while the frontal lobes influences the pattern of their discharges.  相似文献   

18.
一种高速铁路无砟轨道混凝土结构疲劳损伤模型   总被引:1,自引:0,他引:1  
基于连续损伤力学理论和边界面概念,建立了高速铁路无砟轨道混凝土结构在循环荷载作用下的疲劳损伤模型.模型在主坐标系中采用了拉压两个边界面,根据加载面与极限断裂面、边界面之间的位置关系来计算高速铁路无砟轨道混凝土结构在复杂应力状态下的损伤,并由累积损伤与应变能释放率之间的关系确定循环加载中极限断裂面的变化规律.通过将该理论模型嵌入有限元软件ABAQUS的用户材料子程序UMAT,与同类模型进行比较验证了模型的可行性.最后对高速铁路双块式无砟轨道支承层进行了循环动荷载作用下的疲劳累积损伤分析.结果表明该模型不仅能够较好地反映支承层在循环荷载作用下疲劳损伤非线性演变规律,还可以展现其疲劳损伤分布形态的全过程,为研究高速铁路无砟轨道混凝土结构的疲劳损伤与寿命预测,提供了可行的理论分析方法.  相似文献   

19.
Summary In dogs anæsthetized with morphine-chloralosane, the cerebral ventricles are perfused with artificial solutions. After having been warmed up to body temperature, these solutions are allowed to flow into a lateral ventricle by a needle inserted laterally through the skull, the outflow taking place through a second needle placed suboccipitally in the cisterna. An excess of potassium in the cerebral ventricles increases the vasomotor tonus and the vasomotor responses produced by faradization of the central end of the vagus in the neck and by changing the pressure in the isolated carotid sinuses. An excess of calcium depresses the tonus of the vasomotor center and its reflex responses. An excess of calcium may be neutralized by an excess of potassium. Perfusion with a solution containing no calcium increases the tonus and the responses of the vasomotor center, while the absence of potassium does not seem to have any influence on the vasomotor system. A solution without potassium and calcium produces an increase of the tonus and the responses of the vasomotor center, these effects being due to the absence of calcium.  相似文献   

20.
主要研究了机器人系统的鲁棒控制。介绍了机器人的鲁棒控制模型后,利用最优控制问题求解鲁棒控制,这种方法降低的构造Liapunov函数的难度。只需要求解一个代数的黎卡提方程,便可得到最优控制器,而且证明了这个最优控制器也是鲁棒控制器。但又由于基于这种方法得到的控制器较复杂而难以实现,而且能得到渐近稳定的定性结果,而不能得到其平衡点的衰减速率以及平衡点的吸引域的估计。因此在本文的第三部分中应用了算子非线性测废理论。基于非线性测度方法求解的鲁棒控制器,不仅简单易求,而且克服了压缩映像原理估计压缩常数的困难,在得到系统渐近稳定性的同时得到了系统平衡点的衰减速度和吸引域的估计。最后给出了两关节机器人鲁棒控制的的实例。由于控制器设计与f(X)无关,相关结果会比较保守,可为相关设计研究提供一些参考。  相似文献   

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