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1.
维修保障船能够实现远海受损舰船的现场维修,当其进入舰船维修市场时将与修船厂形成一定程度的竞争。为解决维修保障船模式与修船厂模式维修远海受损舰船的最优定价问题,通过分析这两种维修模式在时空以及成本方面的差异,建立维修保障船与修船厂的定价博弈双层规划模型,并设计迭代算法实现模型的求解。以维修远海船体受损的舰船为例,求得了两者的最优定价、最大收益以及船东对两种维修模式的需求,验证了模型与算法的有效性,并分析了调遣距离、舰船受损程度、海上维修技术难度等因素对维修保障船与修船厂定价博弈的影响。该方法能够为维修保障船与修船厂的经营者提供最优定价策略,为两种维修模式的定价博弈提供理论支持。  相似文献   

2.
准正交基与准正交变换   总被引:12,自引:0,他引:12  
利用内积给出了准正交基,准正交变换与准对合变换的概念,研究了它们的性质及其之间的联系,获得了许多新的结果,推广了正交基,正交变换,对合变换的概念,性质以及张禾瑞,郝新,邹本强等先生的相关结果。  相似文献   

3.
采用投入产出分析法,结合部门能源消费数据,从最终需求的角度评估和计算了中国1997年、2002年和2007年的碳排放量、碳排放系数、直接碳排放系数和完全碳排放系数.研究结果表明,金属冶炼及压延加工业、燃气生产和供应业、非金属矿物制品业、电力、热力的生产和供应业、水的生产和供应业以及煤炭开采和洗选业的直接碳排放系数历年均是最高的,能源强度是影响这些行业直接碳排放系数变化的主要因素;金属冶炼及压延加工业、非金属矿物制品业、金属制品业、化学工业、电力、热力的生产和供应业、水的生产和供应业以及煤炭开采和洗选业的完全碳排放系数历年均居前列,中间产品投入和能源强度是影响完全碳排放系数变化的主要因素.针对实证结果,现阶段我国节能减排的重点方向在于调控金属冶炼及压延加工业、化学工业等高碳排放行业,并通过提高能源效率、调整产业结构及优化能源结构来达到降低碳排放系数的目的.  相似文献   

4.
针对政府与企业资源的异质性,从资源禀赋的视角,对政府与企业互动的不同模式(随机合作型、政策驱动型、技术推动型、协作共赢型)的界定与分析,构建政府与企业互动行为的演化博弈模型,明确政府与企业在不同模式下的互动行为演化路径。研究结果表明:政府与企业不同互动模式存在显著差异,不同类型企业与政府之间的互动对应着某种互动模式;不同互动模式的产生和演化契合政企互动关系的发展历程;协作共赢型互动模式是政府与企业互动行为演化的高级阶段,有利于政府与企业形成紧密的合作,激发政府政策资源与企业技术资源的协同效应。  相似文献   

5.
重建微态连续统理论和偶应力理论的动量和动量矩均衡定律以及能量守恒定律,并由这些定律自然地推导出相应的局部和非局部均衡方程。这些结果可由耦合型微极连续统理论过渡和归结而得到。把推导出的结果和传统的质量和微惯性守恒定律以及熵不等式结合在一起就构成微态连续统理论和偶应力理论的基本均衡定律和方程体系。还弄清了以前的各种连续统理论的不完整性层次。最后,给出了几种特殊情形。  相似文献   

6.
认识非线性随机时滞现象的内在机理、运演性态和掌握其内在规律己成为当今非线性随机动力学理论分析与数值分析的重要主题.基于教学论、自组织理论和非线性随机时滞动力学等理论及其有关研究成果,构建教学系统的非线性随机时滞Logistic模型,寻求教学系统的演化规律,并在此基础上研究教学系统的最优习得策略和提出相应教学建议,期望能促进教学系统有序发展;同时,也期望能促使教学论与非线性随机动力学等理论"联姻",拓展与丰富教学论的研究领域,为教学论研究提供一个新的学科视角的支持与论证.  相似文献   

7.
以武汉为例,以高斯扩散模型为基础研究PM2.5的扩散与衰减规律,充分考虑影响PM2.5扩散的因素,分析地面与建筑物边界反射、干沉积、雨洗湿沉积及湿度的影响,逐步改进高斯扩散模型,并引入时间t,计算当点源持续污染情况下,污染源上风和下风L公里处的浓度.通过数值仿真,得到距污染源下风向距离一定条件下污染扩散浓度的分布规律,预估突发情形下PM2.5的扩散距离及安全区域,结合三维图及平面图分析危险区及安全区.最后,结合小波理论及神经网络理论,提出小波神经网络的结构及算法,并通过Matlab实现了对PM2.5值的预测,并取得较高的预测拟合度.  相似文献   

8.
In this paper an analytical procedure is given to study the free vibration and stability characteristics of homogeneous and non-homogeneous orthotropic truncated and complete conical shells with clamped edges under uniform external pressures. The non-homogeneous orthotropic material properties of conical shells vary continuously in the thickness direction. The governing equations according to the Donnell’s theory are solved by Galerkin’s method and critical hydrostatic and lateral pressures and fundamental natural frequencies have been found analytically. The appropriate formulas for homogeneous orthotropic and isotropic conical shells and for cylindrical shells made of homogeneous and non-homogeneous, orthotropic and isotropic materials are found as a special case. Several examples are presented to show the accuracy and efficiency of the formulation. The closed-form solutions are verified by accurate different solutions. Finally, the influences of the non-homogeneity, orthotropy and the variations of conical shells characteristics on the critical lateral and hydrostatic pressures and natural frequencies are investigated, when Young’s moduli and density vary together and separately. The results obtained for homogeneous cases are compared with their counterparts in the literature.  相似文献   

9.
In finance, the explicit modelling of uncertainty takes on a particularly important role. The values of financial derivatives increase in the return volatility of the underlying security. This notion requires a concept of volatility and hence uncertainty. In addition, the choice between modelling in discrete and continuous time is not arbitrary, since it corresponds to a distinction between incomplete and complete markets, respectively, and this distinction matters for asset pricing, financial risk modelling, and inference. Risk and volatility are closely connected, and implied volatility, volatility forecasting, volatility in term structure models, stochastic volatility, and portfolio analysis are considered and related to a more general interplay between cross-sectional and dynamic aspects in finance. Stocks, bonds, and options are considered and placed in the context of efficiency and separation in inference.  相似文献   

10.
Pareto distributions are very flexible probability models with various forms and kinds. In this paper, a new bivariate Pseudo-Pareto distribution and its properties are presented and discussed. Main variables, order statistics and concomitants of this distribution are studied and their importance for risk and reliability analysis is explained. Joint and marginal distributions, complementing cumulative distributions and hazard functions of the variables are derived. Numerical illustrations, graphical displays and interpretations for the obtained distributions and derived functions are provided. An implementation example on defaultable bonds is performed.  相似文献   

11.
The article surveys the main results on the primitivity and local primitivity of digraphs and matrices from the inception of this research area in 1912 by now. We review the universal and special criteria for primitivity and local primitivity as well as universal and special bounds on the exponents and local exponents of digraphs and matrices. We describe some cryptographic applications of this mathematical apparatus for analyzing the mixing properties of block ciphers and keystream generators. The new promising research directions are formulated in the study of primitivity and local primitivity of digraphs and matrices.  相似文献   

12.
There is a growing interest in applying mathematical theories and methods from topology, computational geometry, differential equations, fluid dynamics, quantum statistics, etc. to describe and to analyze scientific regularities of diverse, massive, complex, nonlinear, and fast changing data accumulated continuously around the world and in discovering and revealing valid, insightful, and valuable knowledge that data imply. With increasingly solid mathematical foundations, various methods and techniques have been studied and developed for data mining, modeling, and processing, and knowledge representation, organization, and verification; different systems and mechanisms have been designed to perform data-intensive tasks in many application fields for classification, predication, recommendation, ranking, filtering, etc. This special focus of Mathematics in Computer Science is organized to stimulate original research on the interaction of mathematics with data and knowledge, in particular the exploration of new mathematical theories and methodologies for data modeling and analysis and knowledge discovery and management, the study of mathematical models of big data and complex knowledge, and the development of novel solutions and strategies to enhance the performance of existing systems and mechanisms for data and knowledge processing. The present foreword provides a short review of some key ideas and techniques on how mathematics interacts with data and knowledge, together with a few selected research directions and problems and a brief introduction to the four papers published in the focus.  相似文献   

13.
随着港航业竞争的加剧,港口间的联盟与合作、港口与航运企业纵向一体化不断发展。尤其是,航运企业以收购或投资模式参与港口间的资源整合,形成了更为复杂的港航混合联盟。针对港口间的资源整合与竞争、航运企业与港口一体化等因素,构建港航混合联盟模式的收益模型,对比分析在区域港口竞争模式和港航混合联盟模式下港口和航运企业的收益变化,揭示地理位置、内陆运输成本、航运企业投资效果等因素的作用。结果表明,港航混合联盟模式能够实现整合港口和航运企业的双赢。同时,当港口与内陆的集疏运基础设施薄弱、航运企业的影响力较大时,非合作港口也会受益,此时港航横纵向混合联盟模式有利于推动整个区域港口经济的发展。  相似文献   

14.
科技创新是促进经济增长的源泉和转变经济增长方式的关键,那么科技创新投入对经济增长是否存在积极影响?本文运用时间序列方法,在4变量系统内检验了我国科技创新投入与经济增长的内在关系,实证结果显示:①经济增长和固定资本投资、劳动投入、科技创新投入之间存在着长期均衡的协整关系;②科技创新投入对经济增长具有Granger影响,科技创新投入增加会导致经济增长;③在1-15年滞后期内,科技创新投入对经济增长的短期冲击为正向效应。在实证基础上,进一步分析了科技创新投入对经济增长的作用机理和路径依赖,并由此得出相关结论与政策建议。  相似文献   

15.
16.
We characterize the ordered semigroups which are decomposable into simple and regular components. We prove that each ordered semigroup which is both regular and intra-regular is decomposable into simple and regular semigroups, and the converse statement also holds. We also prove that an ordered semigroup S is both regular and intra-regular if and only if every bi-ideal of S is an intra-regular (resp. semisimple) subsemigroup of S. An ordered semigroup S is both regular and intra-regular if and only if the left (resp. right) ideals of S are right (resp. left) quasi-regular subsemigroups of S. We characterize the chains of simple and regular semigroups, and we prove that S is a complete semilattice of simple and regular semigroups if and only if S is a semilattice of simple and regular semigroups. While a semigroup which is both π-regular and intra-regular is a semilattice of simple and regular semigroups, this does not hold in ordered semigroups, in general.  相似文献   

17.
随着当代科学和技术的发展,复杂非线性系统和控制理论研究不断深入,应用领域不断扩大,已影响了科技和社会领域的许多方面.针对当今该领域的研究难点和重点,本文集中讨论了复杂非线性系统控制研究中的3个关键问题,包括非光滑系统控制、网络化系统控制、临界态分析与控制.一方面是对在相关研究领域中的部分科研成果做一个简要的总结;另一方面,想借此机会在自动化学会控制理论专业委员会成立50周年之际向专业委员会表示感谢和祝贺.  相似文献   

18.
小区域科技实力及其评估体系   总被引:3,自引:0,他引:3  
科技实力是运作主体能够进行并完成科技活动的能力。科技实力是一个评估性概念,它反映了科学技术的创新,发展,转移,推广,储备条件以及管理,效果等不同层面的综合性的特征,科技实力由科技潜在能力(科技势能),科技显现能力(科技动能)构成,它包含了对科技资源及分布状态,科技资源保障能力,科技创新能力,科技开发能力,科技转移能力和科技活动运作能力的综合描述。  相似文献   

19.
This is a summary of research, from an information processing perspective, of children's interpretation and use of strategies and representations for place value, subtraction and addition in the first three years of school. Representations are defined broadly to include concrete embodiments of numbers, symbols for numbers and operations, and combinations of the latter in number sentences and algorithms. The objective was to assess the value and limitations of the use of representations in early mathematics learning and teaching and hence to identify, describe and examine critically some of the strategies and representations that children and teachers use in early mathematics. Children generally chose to use verbal and mental strategies in preference to formal algorithms, and did not want to use analogs unless they could not perform the task in any other way. The latter preference is explained on the basis of the extra demand that use of analogs adds to the cognitive process unless they are used automatically.  相似文献   

20.
This study compared the impacts of traditional classroom and outdoor schoolyard instruction on the environmental science content knowledge and attitudes of 285 third‐ and fourth‐grade students. A modified Solomon Four Group design, including control, classroom treatment, and schoolyard treatment groups, was used. Both the indoor classroom and outdoor schoolyard treatments consisted of corresponding 10‐day units focusing on plant and animal ecology. Valid and reliable content knowledge and attitude assessments were administered before and after instruction. Analyses of variance and post hoc analyses of posttest scores and gain scores indicated that elementary students learned significantly more about selected environmental science topics through outdoor schoolyard experiences than through traditional indoor classroom experiences. Both classroom and schoolyard treatment groups developed more positive environmental attitudes as a result of instruction, but the attitude posttest and gain scores of these two groups were not significantly different from each other.  相似文献   

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