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81.
黄土高原社会-生态系统变化及其可持续性 总被引:4,自引:0,他引:4
在全球变化和人类活动驱动下,社会系统与生态系统均处在不断加剧的动态变化中,揭示二者之间的互馈机制是保持和增强系统弹性以及可持续性的科学基础。黄土高原地区是中国人口、资源、环境矛盾最集中的区域之一,也是黄河重要的产水区和绝大部分泥沙的来源区。合理布局黄土高原土地利用格局,协调黄土高原水土保持和黄河下游水资源利用与泥沙控制,是黄土高原地区和黄河流域可持续发展的重大需求。本文立足于国际社会-生态系统耦合研究前沿和可持续发展与生态建设的国家需求,综述了区域社会系统与生态系统的互馈机制和社会-生态系统的耦合模拟的研究进展,总结了黄土高原社会-生态系统的变化过程和驱动机制,认为发展社会-生态系统动态机制分析方法和稳态转换识别方法,建立耦合社会系统与生态系统的土地利用权衡与优化模型,是推动社会-生态系统耦合研究理论与方法创新、为黄土高原的可持续发展提供科学依据的重要途径。 相似文献
82.
The blockchain is considered to be the potential driver of the digital economy. The Blockchain technology outweighs the challenges associated with the traditional transaction business governed and regulated by the third trusted party. There is a growth in the interest among the researchers, the industry, and the academia to study and leverage the potential of Blockchain. Blockchain provides a decentralized and distributed public ledger for all the participating parties. Though it seems that blockchain is a viable choice and solution for all the centralized governed and regulated transactions (in digital online space), it has potential challenges that need to be resolved; opportunities to be explored, and applications to be studied. This paper utilizes a systematic literature review to study several research endeavors made in the domain of blockchain. To further research on blockchain adoption, the paper theoretically constructs an integrated framework of the blockchain innovation adoption process in an organization considering organizational and user acceptance perspectives. This would facilitate its widespread adoption, thereby achieving sustained leadership solutions. The paper offers 23 propositions to information systems (IS)/information management (IM) scholars with respect to innovation characteristics, organizational characteristics, environmental characteristics, and user acceptance characteristics. Further, the paper explores several areas of future research and directions that can provide deep insights for overcoming challenges and for the adoption of blockchain technology. 相似文献
83.
Jose Alvarez-RamirezGuillermo Fernandez Rodolfo Suarez 《Journal of The Franklin Institute》2002,339(1):29-41
The PI control configuration for stabilization and signal tracking of nonlinear systems is investigated. Semiglobal asymptotic stability and semiglobal practical signal tracking of the controlled system are proven using results from the theory of nonlinear singularly perturbed systems. 相似文献
84.
本文对心理词汇、外语心理词汇、二语心理词汇、双语心理词汇所涉及到的语言与思维关系问题进行了较为深入的分析、阐释和讨论,明确指出:1)在语言习得和外语学习过程中,逻辑思维和形象思维两套系统会因信息输入途径的不同而各自、相继或同时参与着信息加工;2)两种思维系统所参与的信息加工,会以"词条或概念群组"的形式加以储存;3)提出了外语学习信息加工心理词库的假说;4)并对定位论和总体论以及各种类型心理词汇的分类、概念及其信息输入、储存、激活等问题分别进行了简明扼要地阐述、分析和讨论;在此基础上,提出了"人脑信息加工神经网络化体系论"假说。 相似文献
85.
介绍了加气机中基于ARMLPC2131单片机的射频卡的设计方案。针对该射频卡毋须接触、实时快速、稳定性好、工艺精度高的特点,着重介绍了其硬件设计和软件流程。采用该射频卡的加气机在LNG和CNG加气站具有很高的实用价值。 相似文献
86.
严春妹 《浙江教育学院学报》2011,(6):67-71
Murray Bowen家庭系统理论认为,儿童和青少年时确立的"自我"水平可通过自我本人作出长期的努力去改变。《飘》的主人公斯佳丽由于家庭影响而呈现出较低的原生自我分化力,但在经历了三次婚姻、几经努力后,最终实现了自我分化力的转变。 相似文献
87.
王泳 《合肥师范学院学报》2014,32(6):5-8
利用临界点理论研究了Kirchhoff系统的周期解.首先定义Kirchhoff系统的弱解;其次给出一些引理;最后用临界点理论中的极小极大方法得到关于Kirchhoff系统弱解的一个存在性定理. 相似文献
88.
The design problem of collocated feedback controllers is addressed in this paper for a class of semi-linear distributed parameter systems described by parabolic partial differential equation (PDE), where a finite number of local actuators and sensors are intermittently distributed in space. A Lyapunov direct method for the exponential stability analysis of the resulting closed-loop system is first presented for the system, in which the first mean value theorem for integration and the Wirtinger's inequality are employed. The corresponding stabilization condition is then derived through the analysis result. Finally, the proposed design method is implemented on the feedback control of a fisher equation and its effectiveness is evaluated through simulation results. 相似文献
89.
This paper deals with the problem of adaptive output feedback neural network controller design for a SISO non-affine nonlinear system. Since in practice all system states are not available in output measurement, an observer is designed to estimate these states. In comparison with the existing approaches, the current method does not require any information about the sign of control gain. In order to handle the unknown sign of the control direction, the Nussbaum-type function is utilized. In order to approximate the unknown nonlinear function, neural network is firstly exploited, and then to compensate the approximation error and external disturbance a robustifying term is employed. The proposed controller is designed based on strict-positive-real (SPR) Lyapunov stability theory to ensure the asymptotic stability of the closed-loop system. Finally, two simulation studies are presented to demonstrate the effectiveness of the developed scheme. 相似文献
90.
Climate adaptation research increasingly focuses on the socio-cultural dimensions of change. In this context, narrative research is often seen as a qualitative social science method used to frame adaptation communication. However, this perspective neglects an important insight provided by narrative theory as applied in the cognitive sciences and other practical fields: human cognition is organized around specific narrative structures. In adaptation, this means that how we ‘story’ the environment determines how we understand and practice adaptation, how risks are defined, who is authorized as actors in the change debate, and the range of policy options considered. Furthermore, relating an experience through story-telling is already doing ‘knowledge work’, or learning. In taking narrative beyond its use as an extractive social research methodology, we argue that narrative research offers an innovative, holistic approach to a better understanding of socio-ecological systems and the improved, participatory design of local adaptation policies. Beyond producing data on local knowledge(s) and socio-cultural and affective-emotive factors influencing adaptive capacity, it can significantly inform public engagement, deliberation and learning strategies–features of systemic adaptive governance. We critically discuss narrative as both a self-reflective methodology and as a paradigmatic shift in future adaptation research and practice. We explore the narrative approach as a basis for participatory learning in the governance of socio-ecological systems. Finally, we assemble arguments for investing in alternative governance approaches consistent with a shift to a ‘narrative paradigm’. 相似文献