Complexity change and space symmetry rupture

Is complexity growth the result of a continuous process or a sudden breakthrough? An increased energy density rate is the effect or the cause of a complexity leap? Should we approach complexity change by the perspective of components behaviour or system's space geometry? In this work we address some of the questions regarding the theoretical approach to complexity change. For this purpose a case study drawn by the productive structure and the transport system is considered. We would like here to propose an example in which the system structure is reshaped in a more energy intensive fashion as to increase the components’ interactions due to a symmetry rupture in the space. Flows throughout the system are thereby incremented in a discontinuous way by a complexity leap. In the case study, we analyze how the productive system evolved its structure, between 1970s and 1990s, to increase interactions among its parts and thus further develop the transport sub-system. A two-stage shift has been considered: the fordian and the post-fordian productive structure. The second structure, given the same amount of parts, has been shown to increase the degree of freedom (path length and path diversity) of the system. The underlying evolutionary pattern is then analyzed. This evolutionary pattern relies on the hypothesis that thermodynamic evolutionary systems are characterized by an ever growing influx of energy driven into the system by self-catalytic processes that must find their way through the constraints of the system. The system initially disposes of the energy by expanding, in extent and in the number of components, up to saturation due to inner or outer constraints. The two counteractive forces, constraints and growing energy flux, expose the system to new gradients. Every new (spatial) gradient upon the system represents a symmetry rupture in the components’ space. By exploring a new gradient, the system imposes further restrictions on its components and increases its overall degree of freedom. The counteractive effects of reduction/increase of degree of freedom concern two different hierarchical levels and occur at two different space and time scales.     

土地利用/土地覆被变化研究范式的转变

土地利用/土地覆被变化(LUCC)研究的形成和发展经历了从前科学(无范式)到科学(以范式为标志)的历史过程.认识LUCC研究范式及其转变的内涵和实质对其理论和应用的发展与完善具有极为重要的意义,并有助于提高解释和预测能力.本文以库恩的“范式”和“范式转变”为基本脉络,剖析了LUCC研究中的实证主义范式、科学人文主义范式、结构功能主义范式以及复杂性范式,并指出范式及其转变主要在本体论、认识论和方法论三个层面表现出来.实证主义范式强调决定论以及主客体分离,认为应把经验与逻辑分析作为客观地认识现实的基础,它贯穿1UCC不同发展阶段,在初期发挥了重要作用,至今仍主导着LUCC研究;科学人文主义在科学主义或实证主义的基础上强调了人的主体性,修正了它们的片面性;结构功能主义为我们提供了一种可资参考的系统分析方法,在宏观层面的许多重要理论见解和研究方法,值得LUCC研究者关注和借鉴;复杂性范式强调土地系统的非线性、自组织、连通性等特征,为LUCC研究提供了一种新的科学世界观、认识论和方法论,利用复杂性理论研究具有非线性特征的复杂土地系统,体现了当前LUCC研究的范式转变.     

影响除雾器带浆量2个因素的三维模拟研究

湿法烟气脱硫系统(WFGD)中除雾器是一个十分关键的设备.我们利用CFD三维软件模拟计算研究最顶端喷淋层与除雾器之间距离(D)以及空塔速度(V)对进入除雾器浆液量(M)的影响.结果表明,M与D成幂指数关系,而与V成线性关系.此外,进入除雾器的浆液粒径分布可以用Rosin-Rammler分布来拟合.     

An Integrated Framework for Public Sector Environmental Management in Developing Countries

/ Achieving successful and well-integrated environmental management depends on principled and orderly assignment of responsibilities within and between public sector organizations. Guidelines for making these assignments can be found by considering different modes of public response in light of a framework based on some distinguishable patterns in the complexity they exhibit. The basic dimensions of environmental problems can be used to identify these patterns. Two examples from current environmental problems in Taiwan are given, illustrating how this framework can be put to use.     

COMPUTATIONAL IMPROVEMENT FOR STOCHASTIC DYNAMIC PROGRAMMING MODELS OF URBAN WATER SUPPLY RESERVOIRS1

ABSTRACT: This paper describes two methods that are introduced to improve the computational effort of stochastic dynamic programming (SDP) as applicable to the operation of multiple urban water supply reservoir systems. The stochastic nature of streamflow is incorporated explicitly by considering it in the form of a multivariate probability distribution. The computationally efficient Gaussian Legendre quadrature method is employed to compute the conditional probabilities of streamflow, which accounts for the serial correlation of streamflow into each storage and the cross correlation between the streamflow into various storages. A realistic assumption of cross correlation of streamflow is introduced to eliminate the need to consider the streamflow combinations which are unlikely to occur in the SDP formulation. A “corridor” approach is devised to eliminate the need to consider the infeasible and/or inferior storage volume combinations in the preceding stage in computing the objective function in the recursive relation. These methods are verified in terms of computational efficiency and accuracy by using a hypothetical example of three interconnected urban water supply reservoirs. Therefore, it can be concluded that these methods allow SDP to be more attractive for deriving optimal operating rules for multiple urban water supply reservoir systems.     

A CFD based explosion risk analysis methodology using time varying release rates in dispersion simulations

A full probabilistic Explosion Risk Analysis (ERA) is commonly used to establish overpressure exceedance curves for offshore facilities. This involves modelling a large number of gas dispersion and explosion scenarios. Capturing the time dependant build up and decay of a flammable gas cloud size along with its shape and location are important parameters that can govern the results of an ERA. Dispersion simulations using Computational Fluid Dynamics (CFD) are generally carried out in detailed ERA studies to obtain these pieces of information. However, these dispersion simulations are typically modelled with constant release rates leading to steady state results. The basic assumption used here is that the flammable gas cloud build up rate from these constant release rate dispersion simulations would mimic the actual transient cloud build up rate from a time varying release rate. This assumption does not correctly capture the physical phenomena of transient gas releases and their subsequent dispersion and may lead to very conservative results. This in turn results in potential over design of facilities with implications on time, materials and cost of a project.In the current work, an ERA methodology is proposed that uses time varying release rates as an input in the CFD dispersion simulations to obtain the fully transient flammable gas cloud build-up and decay, while ensuring the total time required to perform the ERA study is also reduced. It was found that the proposed ERA methodology leads to improved accuracy in dispersion results, steeper overpressure exceedance curves and a significant reduction in the Design Accidental Load (DAL) values whilst still maintaining some conservatism and also reducing the total time required to perform an ERA study.     

考虑道路状况的应急配发站启用以及配送优化问题*

为了研究应急物资配发站启用及配送方案优化问题,综合考虑灾难事件下的道路损毁状况、道路复杂程度、需求不确定以及物资拆分配送等特点,以应急物资配发站启用成本、车辆启动成本、运输成本之和最小化为目标,建立应急物资配发站启用及配送模型,设计头脑风暴优化算法,结合算例,对该问题进行仿真,并将结果与遗传算法进行对比,验证模型的可行性和算法的有效性。结果表明,在决策时考虑道路状况能够有效降低系统成本,提高救援效率。     

芳香型偶氮污染物紫外光谱量子力学指认及不同共轭态偶氮键电子激发研究

偶氮化合物是重要的工业化学品,也是常见的环境污染物,其紫外激发特征及"分子结构-紫外吸收"的构效关系暂未完全明确.本研究借助量子化学计算,通过对波函数与激发态"电子-空穴"的分析,描述偶氮化合物紫外吸收光谱和激发态特征.结果表明:反式偶氮苯实验紫外光谱的第一主要吸收峰应指认为π→π^*跃迁,对应其S₀→S₂激发,电子从最高占据轨道(HOMO)跃迁到最低未占据轨道(LUMO);它的第一激发过程(S₀→S₁)振子强度很小(f=0.031),对光谱贡献可以忽略.反式偶氮苯吸收峰位置与顺式相比普遍红移,表明反式结构中偶氮键通过"桥接效应"形成全局共轭,降低了激发能,对偶氮化合物的紫外吸收产生显著影响;在水溶液中,钠离子对偶氮键的电荷分布存在显著扰动,因此,孤立阴离子模型计算得到的甲基橙光谱与实验存在较大误差."推拉"电子官能团促使甲基橙分子高度极化,与钠离子和水分子作用较强,正确处理偶氮键附近的阳离子扰动是建立预测模型的关键.通过量子化学计算指认偶氮污染物紫外可见吸收光谱能为污染修复、环境工程技术开发、光学材料合成提供理论依据,具有重要意义.     

An improved grey wolf optimizer algorithm for identification and location of gas emission

Identification of the leakage of hazardous gases plays an important role in the environment protection, human health and safety of industry production. However, lots of current optimization algorithms, such as particle swarm optimization (PSO) and Grey Wolf Optimizer (GWO), suffer from poor global optimization capability and estimation accuracy. In this work, a hybrid differential evolutionary and GWO (DE-GWO) algorithm is proposed. Tested by simulation cases and Prairie Grass emission experimental data, DE-GWO shows higher estimation accuracy than GWO. Compared with the other four optimization algorithms, DE-GWO exhibits finer robust stability under different population sizes, fewer iterations, as well as higher estimation accuracy with fewer search agents. Importantly, simulation results demonstrate that DE-GWO is more suitable to apply in the scene with a small number of sensors. Therefore, the proposed in this paper outperforms other optimization algorithms for the gas emission inverse problem. DE-GWO can provide reliable estimation towards gas emission identification and positioning, which shows huge potential as the data analysis module of real-time monitoring and early warning system.