Water Supply Networks as Cyber-physical Systems and Controllability Analysis

Cyber-physical systems (CPS) is a system of systems which consists of many subsystems that can stand alone in an individual manner and can be taken as a typical complex network. CPS can be applied in the critical infrastructures such as water supply networks, energy supply systems, and so on. In this paper, we analyze the structure of modern city water supply networks from the view of CPS theory. we use complex network theory to build an undirected and unweighted complex network model for the water supply networks to investigate the structural properties, and present the structure of the water supply networks and detect communities by a spectral analysis of the Laplacian matrix. Then, we analyze the structure and controllability of water supply networks by the structural controllability method. The results show the feasibility and effectiveness of the proposed complex network model. © 2014 Chinese Association of Automation.

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.

Dynamic Analysis of Supply and Demand Coupling of Ecosystem Services in Loess Hilly Region:A Case Study of Lanzhou,China

The relationship between the supply and demand for ecosystem services(ESs)is a key issue for the rational allocation of natural resources and optimisation of sustainable development capacity.This paper investigateed the dynamic evolution features of supply and demand of four ESs in Lanzhou of China,namely,water supply,food supply,carbon fixation and soil retention services.The crosssectional data of 2005 and 2017 were used for calculating ESs value and its supply and demand through ArcGIS software,InVEST model,elastic coefficient model and coupling coordination model.Results showed that:1)from 2005 to 2017,the supply of water supply services increased,the demand of soil retention services decreased,and the supply and demand of food supply and carbon fixation services increased.The high-value areas of service supply were mainly distributed in the rocky mountain areas in the southeast and northwest with high vegetation coverage,while the high-value areas of demand were mainly distributed in the urban areas and surrounding areas with high population density.2)There were five different types of coupling relations.Water supply service was dominated by a negative coupling type D,which means that the decrease in demand for ESs has had a positive response on the supply of ESs.Negative coupling type C was the main type of food supply and carbon fixation services,which means that the increase in demand for ESs has had a negative response on the supply of ESs.All three services were supplemented by a positive coupling type A,which means that the increase in demand for ESs has had a positive response on the supply of ESs.Soil retention service generally exhibits a positive coupling type B,which means that the decrease in demand for ESs has had a negative response on the supply of ESs.3)Over the past 12 yr,the coordination degree of supply and demand of water supply,food supply and soil retention services decreased,and the coordination degree of carbon fixation service increased.Various types of ES had a low degree of coupling and coordination,showing different characteristics of temporal and spatial evolution.The areas with imbalanced ESs supply and demand were mainly distributed in urban areas dominated by construction land.The research results are valuable to the optimisation of urban and rural ecological environments and the sustainable development of territory space under the framework of ecological civilisation,including similar ecologically vulnerable areas in other developing countries.

Evaluation and optimization of secondary water supply system renovation

Due to pollution in second water supply system (SWSS),nine renovation alternative plans were proposed and com-prehensive evaluations of different plan based on Analytical Hierarchy Process (AHP) were presented in this paper. Comparisons of advantages and disadvantages among the plans of SWSS renovations provided solid foundation for selecting the most appro-priate plan for engineering projects. In addition,a mathematical model of the optimal combination of renovation plans has been set up and software Lingo was used to solve the model. As a case study,the paper analyzed 15 buildings in Tianjin City. After simulation of the SWSS renovation system,an optimal scheme was obtained,the result of which indicates that 10 out of those 15 buildings need be renovated in priority. The renovation plans selected for each building are the ones ranked higher in the com-prehensive analysis. The analysis revealed that the optimal scheme,compared with two other randomly calculated ones,increased the percentage of service population by 19.6% and 13.6% respectively,which significantly improved social and economical benefits.

System Dynamics Approach to Urban Water Demand Forecasting—A Case Study of Tianjin

A system dynamics approach to urban water demand forecasting was developed based on the analysis of urban water resources system, which was characterized by multi-feedback and nonlinear interactions among sys-tem elements. As an example, Tianjin water resources system dynamic model was set up to forecast water resources demand of the planning years. The practical verification showed that the relative error was lower than 10%. Fur-thermore, through the comparison and analysis of the simulation results under different development modes pre-sented in this paper, the forecasting results of the water resources demand of Tianjin was achieved based on sustain-able utilization strategy of water resources.

The Estimation of Water Supply and Demand in Hotan Oasis

[Objective] The purpose of this study is to estimate water supply and demand, which can provide a basis for how to allocate rationally water resources in Hotan Oasis. [Method] The water supply and demand in Hotan Oasis in the next15 years were calculated according to water-soil balance. [Result] When the runoff of Hotan River is at a probability of 50%（P=50 for short）, the total water resource is 50.57×10^8m^3, and there is only 33.13×10^8m^3available for social and economics,but there would be a need of 33.44×10^8and 36.06×10^8m^3, and the water shortage would be 1.31 ×10^8and 2.93 ×10^8m^3in 2020 and 2030 respectively. When P =75,the total water resource is 44.30×10^8m^3, there is only 29.39×10^8m^3water available for social and economics. However, there would be a need of 31.43 ×10^8and33.11×10^8m^3, and the water shortage would be 2.04×10^8and 3.72×10^8m^3in 2020 and 2030, respectively. [Conclusion] The problem of water shortage would be serious over the next 15 years, and the fragile ecosystem would be destroyed dramatically with the large-scale land reclamation against natural laws. Hence, the effective policies and measures should be taken timely to prohibit reclamation and to cope with ongoing water shortage, based on the water supply and demand estimation under the background of climate change.

Developing and introducing of the resourcesaving technologies into the water-supply systems of mining enterprises

The article deals with modeling the tailing ponds influence on water resources. New technology using hydrocyclons of new design has been offered for additional purification of gold dressing mill wastewater. Laboratory and plant test have determined the optimal parameters of hydrocyclon. Introduction of new technology into system of water supply will prevent environment pollution and make it possible to process recoverable resources.

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.

Low Carbon Economic Dispatch of Integrated Energy System Considering Power Supply Reliability and Integrated Demand Response

Integrated energy system optimization scheduling can improve energy efficiency and low carbon economy.This paper studies an electric-gas-heat integrated energy system,including the carbon capture system,energy coupling equipment,and renewable energy.An energy scheduling strategy based on deep reinforcement learning is proposed to minimize operation cost,carbon emission and enhance the power supply reliability.Firstly,the lowcarbon mathematical model of combined thermal and power unit,carbon capture system and power to gas unit(CCP)is established.Subsequently,we establish a low carbon multi-objective optimization model considering system operation cost,carbon emissions cost,integrated demand response,wind and photovoltaic curtailment,and load shedding costs.Furthermore,considering the intermittency of wind power generation and the flexibility of load demand,the low carbon economic dispatch problem is modeled as a Markov decision process.The twin delayed deep deterministic policy gradient(TD3)algorithm is used to solve the complex scheduling problem.The effectiveness of the proposed method is verified in the simulation case studies.Compared with TD3,SAC,A3C,DDPG and DQN algorithms,the operating cost is reduced by 8.6%,4.3%,6.1%and 8.0%.

Geostatistical Studies of Space-Temporal Variation in Selected Quality Parameters in Klodzko Water Supply System （SW Part of Poland）

Selected results of research connected with the development of a （3D） geostatistical hydrogeocbemical model of the Klodzko city area, dedicated to the spatial and time variation in the quality parameters in the Klodzko water supply system （SW part of Poland） have been presented. The research covers the period 2007-2011. Spatial analyses of the variation in three quality parameters, i.e. Fe iron （g/m3） content, Mn manganese （g/m3） content and NI-I4＋ ammonium ion （g/m3） content, were carried out. Spatial and time variation in the parameters was analyzed on the basis of the data （2007-2011）. The input for the studies was the chemical determinations of the quality parameters of water samples taken in the Klodzko water supply system area （also treated water） in different periods of time. These data were subjected to spatial analyses using geostatistical methods. The parameters of the assumed theoretical models of directional semivariograms functions of the studied regionalized variables, were used in the ordinary （block） kriging estimation. Generally, the behaviour of the quality parameters in the Klodzko water supply system has been found to vary in space and time. Thanks to the multivariate spatial analyses some regularities in the variation in the water supply system in the Klodzko city area have been identified. In the considered time interval, the shapes of the directional Fe iron content semivariogram show a tendency to vary periodically. The courses of the directional semivariograms of Mn manganese content and NI-I4＋ ammonium ion content show some tendencies towards directional variation over the passing years. There are visible distinct increasing trends of variability for Mn content and stronger variation are observed for NH4＋ ion content. The kriging estimation results were used to determine the levels of elevated values 2＊ of the water quality parameters in the years 2007-2011 and to forecast these values for the years 2012-2014. The maximum values Z＊ of the quality parameters were stated for the years： 2007, 2008-2009 and 2012 （the decreasing trend in Fe iron content averages Z＊ variation towards the year 2012, the increasing trend in Mn content averages Z＊ variation towards the year 2012 and the increasing trend in NH4＋ ion content averages Z＊ variation towards the years 2008-2009 and then the decreasing trend towards the year 2012）.

Water Leakages in Public Water Supply System and How to Prevent Them

The article addresses the results of effective water losses prevention in public water supply systems, focusing on procedures for monitoring hidden leaks as the main part of losses and as the first step to control and prevent them. The described methodology has been applied based on a cross-border cooperation between twin capital cities Vienna and Bratislava in the Central Europe Region within the project deWaloP （Developing Water Loss Prevention） and adopted in Bratislava Water Company （BVS） in the Slovak Republic. The paper provides a complex of simple and easily available practices for analyses of water distribution measurements bringing essential information as to the necessity to use advanced procedures to actively reduce leakage. These practices involve minimum night flows analyses, hydrodynamic pressures analyses, pinpointing of water leakages by working with valves in the water network, the methodology of setting alarm limits for measured data, as well as use of advanced practices to obtain missing topologic data. As the water infrastructure in former socialistic countries are in bad technical condition and the lack of pertinent operational data is a significant obstacle to the application of a more sophisticated methodology based on GIS and other information systems, the procedures focus on using the most simple way to evaluate and control water losses. Finally, the introduction of described methodology in Bratislava Water Company after many years of unsuccessful effort even with expensive sophisticated leakage equipment brought positive outputs and the graph line of water losses level is finally going down. The use of expensive multi-correlating equipment together with human resources on the basis of implementing the above described leakage monitoring will subsequently become more effective, as it shall pinpoint major leakages, disclosure and removal of that shall significantly contribute to the effective reduction of water losses.

The Demand Investigation and Suggestions of the Supply System of Preschool Education in Western Areas of China

Nowadays, preschool education has become the weak part of eduction. Thus, the supply system of preschool education has been heatedly discussed accordingly.This thesis makes some suggestions for the supply system innovation of preschool education in western areas, based on the sampling surveys in Yibin.

Energy efficiency performance of multi-energy district heating and hot water supply system

A district heating and hot water supply system is presented which synthetically utilizes geothermal energy,solar thermal energy and natural gas thermal energy.The multi-energy utilization system has been set at the new campus of Tianjin Polytechnic University(TPU),A couple of deep geothermal wells which are 2 300 m in depth were dug,Deep geothermal energy cascade utilization is achieved by two stages of plate heat exchangers(PHE) and two stages of water source heat pumps(WSHP).Shallow geothermal energy is used in assistant heating by two ground coupled heat pumps(GCHPs) with 580 vertical ground wells which are 120 m in depth.Solar thermal energy collected by vacuum tube arrays(VTAs) and geothermal energy are complementarily utilized to make domestic hot water.Superfluous solar energy can be stored in shallow soil for the GCHP utilization.The system can use fossil fuel thermal energy by two natural gas boilers(NGB) to assist in heating and making hot water.The heating energy efficiency was measured in the winter of 2010-2011.The coefficients of performance(COP) under different heating conditions are discussed.The performance of hot water production is tested in a local typical winter day and the solar thermal energy utilization factor is presented.The rusults show that the average system COP is 5.75 or 4.96 under different working conditions,and the typical solar energy utilization factor is 0.324.

Analysis on water supply and demand of North China Plain

A water supply model and a water demand model are developed to exercise resources budgets of the North China Plain with a planning horizon of the year 2030. The budgets indicate that the North China Plain would face serious water stress from 1993 to 2000, and water resources available in the region can not meet the needs of the socioeconomic development and environment from 2000 to 2030. The south/north Water transfer project is the only option to solve the emerging water crisis.

Energy efficiency in a water supply system:Energy consumption and CO_2 emission

This paper presents important fundamentals associated with water and energy efficiency and highlights the importance of using renewable energy sources. A model of multi-criteria optimization for energy efficiency based on water and environmental management policies, including the preservation of water resources and the control of water pressure and energy consumption through a hybrid energy solution, was developed and applied to a water supply system. The methodology developed includes three solutions： （1） the use of a water turbine in pipe systems where pressures are higher than necessary and pressure-reducing valves are installed, （2） the optimization of pumping operation according to the electricity tariff and water demand, and （3） the use of other renewable energy sources, including a wind turbine, to supply energy to the pumping station, with the remaining energy being sold to the national electric grid. The use of an integrated solution （water and energy-） proves to be a valuable input for creating benefits from available hydro energy in the water supply system in order to produce clean power, and the use of a wind source allows for the reduction of energy consumption in pumping stations, as well as of the CO2 emission to the atmosphere.

Application of LINGO to the Solution of the Water Supply System′s Optimal Operation Model

In this research, LINGO is used successfully to solve the water supply system′s optimal operation model. Firstly, the language of LINGO and the using method were studied intensively, on the basis of which the model was transformed to LINGO form and solved successfully. Secondly, the research on the interface between LINGO and the popular office software was made. The optimization software was developed, which had Excel as the workspace and LINGO as the core of computation. Through practice, this software was found stable, easy to use and suitable for the application to the water supply corporations.

Technical System Construction in the Market Trading System for Demand Response Based on the Energy Internet

With the explosive growth of variable renewable energy,the balance between the supply and demand of the power grid is faced with new challenges.Based on the development experience from typical countries and the state quo in China,this paper further analyzes the system architecture and development trend of demand response under the background of Energy Internet.Five dimensions are considered:Energy Internet platform,demand response application scenarios,system architecture,information technology system construction,and demand response development trend.The results show that the application of the Energy Internet platform can effectively solve the problems of data acquisition and processing,“terminal-edge-network-cloud”cooperation of demand response,etc.The system architecture of the demand response platform that supports user resource management,user information access,control instruction receiving,control strategy issuing,and response process monitoring is proposed in this paper.It is also helpful to provide a feasible technical choice for expanding the application services of Energy Internet towards government and society.

Households＇ Assessment of the Water Quality and Services of Multi-model Urban Water Supply System in the Informal Settlements of Dar es Salaam, Tanzania

In the global south wide range of studies highlight the limitations of the single-modelled public urban water system to meeting the endogenous water preferences of the urban population. Studies also touched on the complementary roles of private water actors to the single-modelled public water supply system in the urban water supply network. Multiple of urban water supply systems （multi-model） co-exist in the urban landscape of global south. However, it is unclear and largely inconclusive on the suitable and satisfactory urban water supply model that meets the water consumption needs of informal settlement dwellers in the global south. This study draws the experiences of households in the informal settlements using a case-study with cross-sectional survey strategy to assess the suitability of the multi-model urban water supply system for sustainable urban water supply in the informal settlements. A total of 292 households were randomly sampled alongside 35 purposively sampled private water actors and public water departments. The data were collected through face to face interviews. Findings show that water supply services of the multi-model water supply system are inevitably suitable for the water consumption needs of informal settlements’s dwellers. The operation of the multi-model water supply system is flexible and able to accommodate the diverse water consumption preferences and choices of the different socio-economic groups in the informal settlements. We observed that multiplicity of urban water supply system increases households’ access to water but does not necessarily improve the quality of water serve in the informal settlements. The paper recommended for the formalisation and adoption of the multi-model urban water supply system to meet the growing demand for improved water supply and services in the informal settlements.

System dynamics model of Suzhou water resources carrying capacity and its application

A model of Suzhou water resources carrying capacity （WRCC） was set up using the method of system dynamics （SD）. In the model, three different water resources utilization programs were adopted： （1） continuity of existing water utilization, （2） water conservation/saving, and （3） water exploitation. The dynamic variation of the Suzhou WRCC was simulated with the supply-decided principle for the time period of 2001 to 2030, and the results were characterized based on socio-economic factors. The corresponding Suzhou WRCC values for several target years were calculated by the model. Based on these results, proper ways to improve the Suzhou WRCC are proposed. The model also produced an optimized plan, which can provide a scientific basis for the sustainable utilization of Suzhou water resources and for the coordinated development of the society, economy, and water resources.

Ecosystem Service Flow Insights into Horizontal Ecological Compensation Standards for Water Resource: A Case Study in Dongjiang Lake Basin, China

Water supply services(WSSs) are critical for the regional water balance and water circulation, but relevant studies have not established the relationship between WSSs and human well-being. This research identifies the scope of areas that benefit from WSSs from an ecosystem service flow perspective. Moreover, the path and quantity of the flow of WSSs are simulated to provide a scientific theoretical basis for ecosystem service management and ecological compensation. The Dongjiang Lake Basin is a national priority river basin in China where ecological compensation pilot programmes concerning water resources are top priorities. Dongjiang Lake Basin experienced an increase and then a decrease in the overall supply of water, with an average net water supply of 1096–1500 mm for the years 1995, 2000, 2005 and 2010. The water demand increased each year in service beneficiary areas(SBAs), varying from 387 to 580 mm. Overall, Dongjiang Lake Basin met the net water demands of the actual SBAs in the lower reaches, but a gap in the water supply and demand emerged gradually. This research provides an understanding of the functional mechanisms for the provision, demand and flow of WSSs and provides a scientific theoretical basis for ecosystem service management and ecological compensation.