Ecological water demand:the case of the slope systems in the East Liaohe River Basin

The ecological water demand (EWD) is the least water amount required to maintain the structure and the function of the special eco-system and the temporal scale of a study on the EWD must be a season's time. Based on GIS and RS with the source information of hydrological data of 46 hydrological gauges covering 52 years and the digital images of Landsat TM in 1986, 1996 and 2000, the landscape patterns, precipitation and runoff in the East Liaohe River Basin were analyzed. With the result of the above analysis, the spatial and temporal changes of the ecological water demand in the slope systems (EWDSS) of the East Liaohe River Basin (ELRB) were derived. Landscapes in the ELRB are dispersed and strongly disturbed by human actions. The hydrological regime in ELRB has distinct spatial variations. The average annual EWDSS in the ELRB is 504.72 mm (324.08-618.89 mm), and the average EWDSS in the growth season (from May to September) is 88.29% of the year's total EWDSS .The ultimate guaranteeing ratio of the EWDSS in ELRB is 90%. The scarce EWDSS area in the whole year and in the growth season are 60.47% and 74.01% of the entire basin respectively. The trend of scarce EWDSS area is most serious according to the quantity and area of scarce EWDSS regions.

Modeling and scenario prediction of a natural gas demand system based on a system dynamics method

Based on the study of the relationship between structure and feedback of China’s natural gas demand system, this paper establishes a system dynamics model. In order to simulate the total demand and consumption structure of natural gas in China, we set up seven scenarios by changing some of the parameters of the model. The results showed that the total demand of natural gas would increase steadily year by year and reach in the range from 3600 to 4500 billion cubic meters in 2035. Furthermore, in terms of consumption structure, urban gas consumption would still be the largest term, followed by the gas consumption as industrial fuel, gas power generation and natural gas chemical industry. In addition, compared with the population growth, economic development still plays a dominant role in the natural gas demand growth, the impact of urbanization on urban gas consumption is significant, and the promotion of natural gas utilization technology can effectively reduce the total consumption of natural gas.

Prediction-based Manufacturing Center Self-adaptive Demand Side Energy Optimization in Cyber Physical Systems

Cyber physical systems（CPS） recently emerge as a new technology which can provide promising approaches to demand side management（DSM）, an important capability in industrial power systems. Meanwhile, the manufacturing center is a typical industrial power subsystem with dozens of high energy consumption devices which have complex physical dynamics. DSM, integrated with CPS, is an effective methodology for solving energy optimization problems in manufacturing center. This paper presents a prediction-based manufacturing center self-adaptive energy optimization method for demand side management in cyber physical systems. To gain prior knowledge of DSM operating results, a sparse Bayesian learning based componential forecasting method is introduced to predict 24-hour electric load levels for specific industrial areas in China. From this data, a pricing strategy is designed based on short-term load forecasting results. To minimize total energy costs while guaranteeing manufacturing center service quality, an adaptive demand side energy optimization algorithm is presented. The proposed scheme is tested in a machining center energy optimization experiment. An AMI sensing system is then used to measure the demand side energy consumption of the manufacturing center. Based on the data collected from the sensing system, the load prediction-based energy optimization scheme is implemented. By employing both the PSO and the CPSO method, the problem of DSM in the manufac^ring center is solved. The results of the experiment show the self-adaptive CPSO energy optimization method enhances optimization by 5% compared with the traditional PSO optimization method.

Testing the Adding up Condition in Demand Systems

A test of the adding up condition in demand systems is crucial for determining whether a share format is admissible when the number of sample goods is smaller than the number of commodity choices available to consumers. This test requires the estimation of a demand system in a quantity format. It cannot be performed when a demand system is specified in share format. The share specification of any demand system is like a straight jacket: once worn, it forces the error covariance matrix to be singular and the adding up condition to hold whether or not the data generating process warrants it. The empirical verification of the adding up hypothesis uses a five-commodity sample selected from the Canadian Family Expenditure Survey with 4847 observations. Three specifications are considered: AIDS (Almost Ideal Demand System), QUAIDS (Quadratic AIDS) and EASI (Exact Affine Stone Index). The hypothesis is rejected in all three cases with a high level of confidence.

支撑新能源电力系统灵活性需求的用户侧资源应用与关键技术

伴随着传统电力系统向以新能源为主体的新型电力系统转型升级,高比例新能源的接入和传统机组占比下降导致电力系统灵活性产生缺额。电动汽车、数据中心、P2X(power-to-X)等需求侧资源可以在多时间尺度为电力系统提供灵活性,是新型电力系统灵活性的重要组成部分。该文首先描述高比例新能源背景下输电网和配电网在不同时间尺度的灵活性需求,然后对比总结了典型需求侧资源的调节特性与应用实践,研究了需求侧资源在支撑高比例新能源输电网和配电网中运行、规划2个层面多时间尺度灵活性需求的应用场景。最后针对未来需求侧资源的研究重点,从聚合技术、电碳协同优化调控策略、可信调节能力量化和通信与信息交换标准等角度,对支撑新型电力系统需求侧资源应用的关键技术进行了总结与展望。

Demand Elasticity for China's Major Imported Agriculture Textile Material Based on Restricted Version of Source Differentiated Almost Ideal Demand System Model

By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal demand system( RSDAIDS) is used to estimate the income and price elasticity of major imported agriculture textile material from the major sources based on the data from 1992 to 2015. The results are shown as follows.( 1) Although the dependency on imported cotton is lower than wool, the fluctuation of cotton import is much more drastic; China's demand for cotton is relatively price elastic with higher expenditure elasticity compared with wool; besides,the existence of complementarity is proved between imported cotton and wool.( 2) According to the import elasticity of cotton,demand for cotton imported from India shows priority over cotton from other sources; demand for cotton imported from America is the most price-sensitive one; substitution among cotton from different sources is weak.( 3) According to the import elasticity of wool,wool imported from Uruguay has bright market prospects. In addition,wool imported from Australia has irreplaceable advantage than that from New Zealand.

Analyzing Effect of Demand Rate on Safety of Systems with Periodic Proof-tests

Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only system parameters, such as configuration, hazard rate, coverage, repair rate, etc. along with periodic proof-tests （or inspection）. Not considering demand rate will give a pessimistic safety estimate for an application with low demand rate such as nuclear power plants, chemical plants, etc. In this paper, a basic model of IEC 61508 is used. The basic model is extended to incorporate process demand and behavior of electronic- and/or computer-based system following diagnosis or proof-test. A new safety index, probability of failure on actual demand （PFAD） based on extended model and demand rate is proposed. Periodic proof-test makes the model semi-Markovian, so a piece-wise continuous time Markov chain （CTMC） based method is used to derive mean state probabilities of elementary or aggregated state. Method to determine probability of failure on demand （PFD） （IEC 61508） and PFAD based on these state probabilities are described. In example, safety indices of PFD and PFAD are compared.

基于组合赋权与灰云模型的综合能源系统需求响应效益评价

考虑到当前综合能源系统研究缺乏完善的需求响应量化评估方案,难以在优化运行层面综合评估需求响应效益这一问题,提出了一种基于改进AHP群决策—CRITIC组合赋权与灰云模型的综合能源系统需求响应效益评价方法。首先,从综合能效性、社会经济性和需求侧互动性三个维度构建了需求响应效益评价指标体系。其次,采用一致性和权重拟合性更优的指数标度法构造判断矩阵,降低赋值误差,并通过AHP群决策法确定主观权重,从而削弱主观极值偏差对权重的影响;在由CRITIC法确定客观权重后,基于最小欧氏距离建立组合权重模型,并通过非线性规划求取最优组合权重;针对评价等级信息的模糊性与隶属等级的随机性,采用正态灰云白化权模型确定指标分类等级与场景评分。最后,以北方某综合能源系统为例,根据用户参与需求响应方式设置了4种运行场景,分析了不同需求响应对系统运行的影响与作用,算例结果表明所提指标体系与评价方法科学有效。

计及成本和价值的长周期负荷侧调节能力投入策略

随着新型电力系统的发展,负荷侧调节能力建设日益受到关注,对于负荷侧调节能力成本、价值及其投入策略的研究,具有重要意义。基于近10 a来中国电力工业发展的基础数据,结合新型电力系统发展态势,分析了负荷侧调节能力需求的背景,通过对发用电两侧调节能力特点的比较,从电力系统整体角度梳理了负荷侧调节能力的投入所带来的增量价值,分析了负荷侧调节能力的应用价值盈余,进一步结合具体需求提出了3种长周期下负荷侧调节能力投入的优化策略模型,并进行了算例分析。结果显示:负荷侧调节能力的投入有利于降低电力系统的总成本、增加系统调节能力,但是由于其成本曲线的变化以及“非持久特性”等因素,其投入策略需要综合长周期市场发展需求和发用电两侧成本因素进行权衡,所提出的3种优化模型各有其适用场景。

考虑用户比价行为的综合需求响应低碳优化策略

在我国“双碳”背景下,建立综合能源系统(integrated energy system,IES)已经成为实现“碳达峰”、“碳中和”目标,加快能源结构转型的重要举措,而综合需求响应(integrated demand response,IDR)是综合能源系统减少碳排放、缓解供需双侧不平衡的有效途径。然而,现有关于IDR的研究大多仅考虑其经济效益,未考虑其环境效益,忽略了需求侧用户对不同时段激励价格的比价行为以及不同用户的差异化响应特性。该文提出了基于碳排放因子的IDR碳排放折算模型,并将碳排放成本加入综合能源系统服务商(integrated energy system provider,IESP)的目标函数中;通过建立激励交叉弹性耦合矩阵对用户的比价行为进行了有效建模以提升模型的精确性;同时计及用户的差异化响应特性,通过制定差异化的激励策略以充分挖掘用户的响应潜力。所提模型被建立为一个IESP-用户双层优化模型,并将该模型转化为了一个单层的凸优化模型以实现高效地求解。最后通过仿真算例验证了模型的有效性,不仅减少了碳排放量,同时降低了IESP的响应成本并提升了用户的舒适度,实现了多方共赢。

The 3D simulation and optimized management model of groundwater systems based on eco-environmental water demand

Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.

省域国土空间生态修复规划体系构建的逻辑与实践——基于“规划—设计—治理”的视角

国土空间生态修复是推进国土空间治理的重要手段,厘清其规划体系的构建逻辑对于国土空间生态修复规划的编制实施和作用发挥至关重要。从需求层次出发,阐明国土空间生态修复规划体系构建的基本逻辑,以浙江省为例,探索建立省域国土空间生态修复规划体系构建的理论。研究表明:(1)国土空间生态修复规划在需求层面上可体现为“功能修复—韧性提升—价值实现”3个层次。(2)围绕着“整体规划—深化设计—系统治理”的逻辑,提出国土空间生态修复规划作为专项规划的体系构建逻辑。(3)基于构建逻辑,将省域国土空间生态修复规划梳理形成“编制—实施—支撑”3个体系。国土空间生态修复规划要从需求层次变化的认识入手,以维护生态安全、提升空间价值为目标,在省域范围内通过纵向传导、横向深化及全流程支撑3个维度构建规划体系,为系统化开展国土空间生态修复工作探索实施路径。

计及多重需求响应的综合能源系统多时间尺度低碳运行

为挖掘需求侧资源响应潜力,文中提出一种计及多重需求响应的综合能源系统(integrated energy system,IES)多时间尺度低碳调度策略。首先,考虑到需求侧资源在不同时间尺度下的响应差异性,建立计及价格型和激励型的多重综合需求响应(integrated demand response,IDR)模型。然后,为减少源、荷预测误差对IES运行的影响,分别构建日前低碳经济调度模型和日内双时间尺度滚动优化平抑模型。最后,算例仿真设置不同场景进行对比分析。结果表明,相比传统IDR,多重IDR能有效挖掘用户响应潜力,提升系统经济性。此外,计及多重IDR的多时间尺度调度策略能有效缓解源、荷误差带来的功率波动并降低系统碳排放量,实现IES低碳、经济和稳定运行。

电动车跨临界CO_(2)热系统充注定量需求规律及非适充系统失稳特性

跨临界CO_(2)热系统是解决电动车“低温续航衰减”和“热系统工质温室效应强”主要问题的最佳技术之一,而电动车多变场景耦合跨临界循环复杂性,系统性能及运行稳定性强依赖于充注量。通过仿真研究了跨临界CO_(2)热系统在不同工况下的CO_(2)充注量定量需求变化规律。重点研究了环境温度、室内风量和室外风速这3个关键因素对不同模式下的系统制冷剂需求量的影响机理和定量表征;并探讨了在非适充场景下的系统动态特性。结果表明:热泵模式下,制冷剂需求下限随环境温度的升高、室内风量的降低和室外风速的增加而增大,其定量影响幅度为18.6%、6.16%和18.9%。制冷模式下,制冷剂需求下限则随环境温度的降低、室内风量的降低和室外风速的增加而增大,其定量影响幅度为7.03%、7.85%和2.27%。在非适充工况下,因非适充下的系统控制量与目标量作用关系发生潜在变化,导致系统出现失控,需要通过制冷剂分布调控缓解特殊工况的系统不稳定性。研究结果对于优化电动汽车空调系统储液器设计、提高其能效和舒适性具有重要参考价值。

Battery Energy Storage System and Demand Response Based Optimal Virtual Power Plant Operation

With certain controllability of various distribution energy resources (DERs) such as battery energy storage system (BESS), demand response (DR) and distributed generations (DGs), virtual power plant (VPP) can suitably regulate the powers access to the distribution network. In this paper, an optimal VPP operating problem is used to optimize the charging/discharging schedule of each BESS and the DR scheme with the objective to maximize the benefit by regulating the supplied powers over daily 24 hours. The proposed solution method is composed of an iterative dynamic programming optimal BESS schedule approach and a particle swarm optimization based (PSO-based) DR scheme approach. The two approaches are executed alternatively until the minimum elec-tricity cost of the whole day is obtained. The validity of the proposed method was confirmed with the obviously decreased supplied powers in the peak-load hours and the largely reduced electricity cost.

公办园非在编教师人事制度改革:利益相关主体的诉求及对策建议

高质量学前教育体系是高质量教育体系建设的基础,学前教师是实现学前教育普及普惠与优质发展的关键力量。公办园非在编教师人事制度改革有助于为占学前教师近八成的非在编教师的人事制度改革提供重要参考。充分考虑多元利益相关者的诉求有助于减少改革的阻力,提升改革的可行性与有效性。本研究运用问卷法和访谈法,着重探讨公办园非在编教师、园长、举办者、教育行政部门四类核心与重要利益相关主体对公办园非在编教师人事制度改革的主要诉求,并基于以上诉求,从创新编制管理机制、健全待遇经费保障机制、建立同工同酬制度、保障专业发展机会等方面提出改革完善公办园非在编教师人事制度的对策建议。

四维水资源供需混沌系统的自适应滑模同步

研究了水资源供需混沌系统的自适应滑模同步,根据李雅普诺夫稳定性理论和同步控制相关理论给出了同步控制的研究结论,并用Matlab仿真技术画出了吸引子相图和系统的误差曲线,并用仿真算例给出了系统参数的选取以及初始值的设置,对所得结果进行了数值验证.

草地培育的内涵和方法

草地培育在草业科学理论指导下,通过一系列草地管理措施,解决草-畜供需季节性不平衡这一根本性矛盾,提高和完善草业系统的结构与功能。根据草地培育的作用目标或其尺度与属性、实施主体有5种划分方法。主要包括封育、休牧、划破、补播、施肥、灌溉、火烧、放牧、人工增雨、研学旅游、智慧管理、政策法规等,这些方法通过改变草业系统或其组分而融入草畜反馈机制。草地培育遵循产业化、慎重改造、综合性和尺度对应等原则,集成技术之间协同或叠加,效果达到超饱和或盈饱和,关键是确定生态系统对培育措施的适应期、响应期和饱和期3组阈值。草地培育建立以放牧为基础的边牧边育的模式,重视“有害”生物作为生态系统不可替代的组分及其资源属性,建设以草地健康水平为基础的标准化的草地培育流程,推动智能化、机械化、规模化作业,提高培育效率和效益。

Time-variant fragility analysis of the bridge system considering time-varying dependence among typical component seismic demands

This paper presents a copula technique to develop time-variant seismic fragility curves for corroded bridges at the system level and considers the realistic time-varying dependence among component seismic demands. Based on material deterioration mechanisms and incremental dynamic analysis, the time-evolving seismic demands of components were obtained in the form of marginal probability distributions. The time-varying dependences among bridge components were then captured with the best fitting copula function, which was selected from the commonly used copula classes by the empirical distribution based analysis method. The system time-variant fragility curves at different damage states were developed and the effects of time-varying dependences among components on the bridge system fragility were investigated. The results indicate the time-varying dependence among components significantly affects the time-variant fragility of the bridge system. The copula technique captures the nonlinear dependence among component seismic demands accurately and easily by separating the marginal distributions and the dependence among them.

考虑需求响应及不确定性的综合能源优化调度

如何在区域综合能源系统中建立有效的需求侧模型,对于需求响应政策的实施至关重要。为提高用户参与需求响应积极性,引入实时定价机制,同时考虑系统的经济低碳性和电气热用户的用能满意度,构建兼顾系统和用户利益的综合需求响应主从博弈模型。针对用户参与需求响应的不确定性,引入贝叶斯方法更新负荷曲线。算例分析表明,所提博弈模型及贝叶斯方法能够有效平衡系统和用户之间的利益,提高了综合需求响应的可靠性。