Knowledge co-production for Indigenous adaptation pathways: Transform post-colonial articulation complexes to empower local decision-making

Co-production between scientific and Indigenous knowledge has been identified as useful to generating adaptation pathways with Indigenous peoples, who are attached to their traditional lands and thus highly exposed to the impacts of climate change. However, ignoring the complex and contested histories of nation-state colonisation can result in naïve adaptation plans that increase vulnerability. Here, through a case study in central Australia, we investigate the conditions under which co-production between scientific and Indigenous knowledge can support climate change adaptation pathways among place-attached Indigenous communities. A research team including scientists, Ltyentye Apurte Rangers and other staff from the Central Land Council first undertook activities to co-produce climate change presentations in the local Arrernte language; enable community members to identify potential adaptation actions; and implement one action, erosion control. Second, we reflected on the outcomes of these activities in order to unpack deeper influences. Applying the theory of articulation complexes, we show how ideologies, institutions and economies have linked Indigenous societies and the establishing Australian nation-state since colonisation. The sequence of complexes characterised as frontier, mission, pastoral, land-rights, community-development and re-centralisation, which is current, have both enabled and constrained adaptation options. We found knowledge co-production generates adaptation pathways when: (1) effective methods for knowledge co-production are used, based on deeply respectful partnerships, cultural governance and working together through five co-production tasks—prepare, communicate, discuss, bring together and apply; (2) Indigenous people have ongoing connection to their traditional territories to maintain their Indigenous knowledge; (3) the relationship between the Indigenous people and the nation-state empowers local decision-making and learning, which requires and creates consent, trust, accountability, reciprocity, and resurgence of Indigenous culture, knowledge and practices. These conditions foster the emergence of articulation complexes that enable the necessary transformative change from the colonial legacies. Both these conditions and our approach are likely to be relevant for place-attached Indigenous peoples across the globe in generating climate adaptation pathways.     

多智能体系统分布式事件触发控制综述

随着人工智能以及通信技术的发展,减少通信资源及计算资源的浪费,延长宽带和硬件的使用寿命成为了一个关键的问题.事件触发控制,即当某一变量超过给定阈值时,系统才进行采样,控制器才进行更新,有效地节约了线上通信及计算资源.本文首先分析了连续时间和离散时间下的事件触发控制,讨论了自触发控制、基于边的事件触发控制、动态事件触发控制以及异步事件触发控制的主要思想.其次,分别从一致性、优化以及博弈方面阐述了事件触发的广泛应用.同时,给出了两种常见的稳定性分析方法和两种排除系统中可能存在的Zeno行为的论证方法.最后对本文进行了总结,指出了当前事件触发工作的不足之处并对未来的研究做出展望.     

一类具有输入量化和未知扰动的非线性系统的自适应有限时间动态面控制

本文研究了具有量化输入信号和未知扰动的非线性系统的有限时间自适应输出反馈动态面控制问题.在控制设计过程中,利用模糊逻辑系统对系统中的非线性项进行逼近.然后引入一种滞回量化器来避免量化信号中的抖振,并且构造模糊观测器来估计系统中不可测的状态.为了提出一种有限时间控制策略,首先给出了半全局实际有限时间稳定的判据.在此基础上,将动态面控制技术与反步法相结合,设计了自适应模糊控制器.该控制器不仅能保证跟踪误差在有限时间内收敛到原点的一个小邻域,而且可以保证闭环系统中所有信号的有界性.最后通过一个仿真实例验证了该控制方法的有效性和可行性.     

Social preferences regarding the delivery of ecosystem services in a semiarid Mediterranean region

The valuation of ecosystem services has primarily been conducted within the context of the economic value of these services to society. Ecosystem services research has since advanced to identify conflicts of interest between different sectors of society while prioritizing conservation actions. This approach can be important in semiarid ecosystems, where biodiversity conservation can be hindered by a lack of community awareness. In the south-eastern Iberian Peninsula, conservation is perceived by society as a barrier to the economic development provided by agricultural or tourism activities. We use the contingent valuation method to identify community perception and economic values of different ecosystem services provided by semiarid ecosystems in the south-eastern Iberian Peninsula. This method identifies the perceptions of individuals benefiting from ecosystem services and examines their willingness to pay for the maintaining of these ecosystem services. Results showed that most respondents recognized the importance of services to human well-being and were willing to conserve these services. Preferences for maintaining water and air quality showed that respondents understood the relationship between the conservation of ecosystem services and local well-being. However, responses varied greatly across categories of beneficiaries; this finding highlights a potential conflict of interest that should be considered in any decision-making processes.     

Burial and infilling of a karst in Papua New Guinea by road erosion sediments

The anthropogenic impact on karst in Papua New Guinea is briefly introduced and a specific case is presented detailing the effect of road erosion sediments on a small karst. The karst is in the perennially humid tropics and covered with primary rain forest. The road was placed high above the karst on steep friable rock and traverses several of its catchments. The changes to and the rate of burial of parts of the karst and the infilling of the caves are described. The karst drainage has altered, and there is increased water storage. The sediment build-up ceased in less than a year due to vegetation and stabilization of the road embankments. It is concluded that any construction within a catchment leading to a karst should be assessed as to its impact on the karst.     

On the application of optimization methods to the determination of members of families of periodic solutions

The techniques used for the numerical computation of families of periodic orbits of dynamical systems rely on predictor-corrector algorithms. These algorithms usually depend on the solution of systems of approximate equations constructed from the periodicity conditions of these orbits. In this contribution we transform the root finding procedure to an optimization one which is applied on an objective function based on the exact periodicity conditions. Thus, the determination of periodic solutions and families of such orbits can be accomplished through unconstrained optimization. In this paper we apply and compare some well-known minimization methods for the solution of this problem. The obtained results are promising. This revised version was published online in July 2006 with corrections to the Cover Date.     

Migration of giant planets in planetesimal discs

Planets orbiting a planetesimal circumstellar disc can migrate inward from their initial positions because of dynamical friction between planets and planetesimals. The migration rate depends on the disc mass and on its time evolution. Planets that are embedded in long-lived planetesimal discs, having total mass of 10⁻⁴– 0.01 M_⊙ , can migrate inward a large distance and can survive only if the inner disc is truncated or as a result of tidal interaction with the star. In this case the semimajor axis, a , of the planetary orbit is less than 0.1 au. Orbits with larger a are obtained for smaller values of the disc mass or for a rapid evolution (depletion) of the disc. This model may explain not only several of the orbital features of the giant planets that have been discovered in recent years orbiting nearby stars, but also the metallicity enhancement found in several stars associated with short-period planets.     

On the Chermnykh-Like Problems: I. the Mass Parameter μ = 0.5

Following Papadakis (2005)'s numerical exploration of the Chermnykh's problem, we here study a Chermnykh-like problem motivated by the astrophysical applications. We find that both the equilibrium points and solution curves become quite different from the ones of the classical planar restricted three-body problem. In addition to the usual Lagrangian points, there are new equilibrium points in our system. We also calculate the Lyapunov Exponents for some example orbits. We conclude that it seems there are more chaotic orbits for the system when there is a belt to interact with.