Yanpeng Cai

Development of a web-based decision support system for supporting integrated water resources management in Daegu city, South Korea

Demands on fresh water by human beings have been continuously increasing due to population growth, living standard improvement, and economic development. At the same time, many regions are suffering greatly from floods and droughts. Those are the results of ineffective management of water resources due to the associated complexities. In this study, a decision support system (DSS) was developed for supporting integrated water resources management in Daegu city, Republic of Korea. The developed DSS contained four subsystems including database, modelbase, and knowledgebase, as well as general user interface (GUI). It was then connected with the National Water Management Information System (WAMIS). A flow prediction could be conducted through the incorporated HEC-HMS Version 3.0.1. Also, an urban water demand forecasting model was developed using an artificial neural network (ANN) based model. At the same time, a water resources management model based on genetic algorithm (GA) was developed in the DSS, facilitating efficient allocation of water resources among different regions within a city. The result indicated that the developed DSS is very useful to deal with complex water resources management problems and could be further applied to similar cities in South Korea.

ICCSIP: An Inexact Chance-Constrained Semi-infinite Programming Approach for Energy Systems Planning under Uncertainty

Abstract This article developed an inexact chance-constrained semi-infinite programming (ICCSIP) method for the energy management system under functional interval uncertainties. The approach not only considers the left-hand interval parameters, right-hand distribution information, and the probability of violating constraint, but also deals with functional interval uncertainty, which extends the range of the uncertainties. A regional energy management system is applied to illustrate the applicability of the ICCSIP approach. In consideration of energy sources allocation, fuel prices, and environmental regulations, a systematic planning of the regional energy structure is desired to bring a significant increase of economic benefit and improvement of environmental quality. This problem can be formulated as a programming model with an objective of minimizing the overall system costs subject to a number of environmental, economic and energy sources availability constraints. The programming results indicate that reasonable and useful decision alternatives can be generated under different probabilities of violating the system constraints. The obtained results are useful for decision makers to gain an insight into the tradeoffs among environmental, economic and system reliability criteria.

Coupled planning of water resources and agricultural land-use based on an inexact-stochastic programming model

Water resources are fundamental for support of regional development. Effective planning can facilitate sustainable management of water resources to balance socioeconomic development and water conservation. In this research, coupled planning of water resources and agricultural land use was undertaken through the development of an inexact-stochastic programming approach. Such an inexact modeling approach was the integration of interval linear programming and chance-constraint programming methods. It was employed to successfully tackle uncertainty in the form of interval numbers and probabilistic distributions existing in water resource systems. Then it was applied to a typical regional water resource system for demonstrating its applicability and validity through generating efficient system solutions. Based on the process of modeling formulation and result analysis, the developed model could be used for helping identify optimal water resource utilization patterns and the corresponding agricultural land-use schemes in three sub-regions. Furthermore, a number of decision alternatives were generated under multiple water-supply conditions, which could help decision makers identify desired management policies.

Inexact Optimization Model for Supporting Waste-Load Allocation in the Xiangxi River Basin of the Three Gorges Reservoir Region, China

AbstractIn this study, a large-scale inexact two-stage waste-load allocation (ITS-WLA) model is developed to identify desired decision alternatives for supporting economic development and water quality management. In this model, uncertainties expressed as both probability distributions and discrete intervals are incorporated within a general optimization framework. A two-step interactive solution algorithm is used to generate interval solutions, and four scenarios are developed to examine tradeoffs between system benefits and system-failure risks. The ITS-WLA model applied to a case study in Xingshan County, China. Because of the extensive impacts of the Three Gorges Reservoir (TGR), the largest newly built reservoir worldwide, Xingshan County is facing many challenges in formulating development strategies. It is thus desired to develop effective decision-support tools to help local decision makers identify strategies to balance economic development and water-quality protection. This study represents a fi...

An enhanced export coefficient based optimization model for supporting agricultural nonpoint source pollution mitigation under uncertainty

In this research, an export coefficient based dual inexact two-stage stochastic credibility constrained programming (ECDITSCCP) model was developed through integrating an improved export coefficient model (ECM), interval linear programming (ILP), fuzzy credibility constrained programming (FCCP) and a fuzzy expected value equation within a general two stage programming (TSP) framework. The proposed ECDITSCCP model can effectively address multiple uncertainties expressed as random variables, fuzzy numbers, pure and dual intervals. Also, the model can provide a direct linkage between pre-regulated management policies and the associated economic implications. Moreover, the solutions under multiple credibility levels can be obtained for providing potential decision alternatives for decision makers. The proposed model was then applied to identify optimal land use structures for agricultural NPS pollution mitigation in a representative upstream subcatchment of the Miyun Reservoir watershed in north China. Optimal solutions of the model were successfully obtained, indicating desired land use patterns and nutrient discharge schemes to get a maximum agricultural system benefits under a limited discharge permit. Also, numerous results under multiple credibility levels could provide policy makers with several options, which could help get an appropriate balance between system benefits and pollution mitigation. The developed ECDITSCCP model can be effectively applied to addressing the uncertain information in agricultural systems and shows great applicability to the land use adjustment for agricultural NPS pollution mitigation.

An improved method for integrated water security assessment in the Yellow River basin, China

Water is a major limiting factor of human survival and social economic development. Water security is also important for the ecological system. In this paper, the water security assessment index system of the Yellow River basin was developed based on three subsystems: the water resources subsystem, the water environment subsystem and the social economic subsystem. The integrated assessment of water security was developed based on the combination of set pair analysis (SPA) and fuzzy analytical hierarchy process (FAHP) as well as technique for order preference by similarity to ideal solution (TOPSIS), gray relational analysis (GRA), vague sets (VS) and matter element (ME) models. First, fuzzy cluster analysis method was used to check the consistency of all the models before and after implementing the integrated assessment. Secondly, the ranking values of four single assessment models (i.e., TOPSIS, GRA, VS and ME models) were analyzed by SPA method to get the consistency connection degree. Then FAHP was constructed to describe the relative importance of the four different single models when determining the weight coefficient in the integrated assessment model. And lastly, the integrated assessment model of water security was developed based on the ranking values and weight coefficients of the selected single assessment models. The conclusion of the developed integrated assessment model which was applied in the Yellow River basin showed that Sichuan province was at security level; Henan, Shandong, Qinghai and Shaanxi provinces were at the threshold security level; Shanxi, Gansu and Inner Mongolia provinces were at the relative insecurity level; Ningxia province was water no secure. The integrated assessment results showed that the improved integrated model presented in this paper had relatively better performance than single assessment models. The intention of this paper was to provide an integrated assessment model, propose potential countermeasures, and achieve sustainable water utilization in the Yellow River basin.

Analysis of relationships between NDVI and climatic/hydrological parameters in the Yellow River basin

NDVI is a key factor for describing variations of vegetation covers. In this research, NDVI values from 15 subregions and the main stream of the Yellow River basin during 1982-1998 were obtained and analysed. The results indicated that their peak values were observed in July or August annually. Annual mean values of NDVI increased across the basin except in the San-Hua and Upper-long subregions, implying that vegetation covers in most of the Yellow River basin were increasing over the 17 years. Moreover, significant positive correlations existed between NDVI values and climatic factors except a certain degree of time lags.

AN INTEGRATED GAME-THEORY BASED MODEL FOR TRANS-BOUNDARY WATER RESOURCES MANAGEMENT IN NORTH CHINA: A CASE STUDY IN THE GUANTING RESERVOIR BASIN (GRB), BEIJING

Water is a fundamental resource in our daily lives and for social development. Currently, water resources are under stressed conditions in north China due to the ongoing growth of demand for water and the frequent occurrences of natural disasters in this area. This problem is further intensified by the deterioration of water quality, which is a side effect of economic development, industrial expansion, and agricultural growth. These problems interconnect with each other, leading to a variety of conflicts over water resources. To resolve such conflicts, a two-person game-theory based model is developed for water resource management in the trans-boundary regions of a river basin. The model is tested on a river basin within this area of China in which water resources are contested. Through the developed model, potential policy alternatives can be generated for water resource management and pollution control within the context of a river basin. Cooperative and/or competitive mechanisms can thus be formulated through competition and cooperation over issues of water quantity and quality among different levels of jurisdictions in the same river basin. Then, Nash Solution is used to solve scenarios of competition and cooperation between the upstream and downstream based on the integration of optimization and simulation models. The developed model and the solution process is then applied to resolve water conflicts between Beijing and Hebei province, which are in the upstream and downstream of the Guanting Reservoir Basin (GRB), respectively, representing two major stakeholders in the contest over water quantity and quality. Non-cooperative and cooperative scenarios for the two-player game scenarios are developed to investigate and compare potential economic benefits of these scenarios. Results indicate that the developed model can be effectively and flexibly employed to resolve water conflicts between upstream and downstream stakeholders in the same river basin. The results can also be used to help formulate economic compensation mechanisms within these jurisdictions.

An Integrated Approach of System Dynamics, Orthogonal Experimental Design and Inexact Optimization for Supporting Water Resources Management under Uncertainty

An integrated approach of system dynamics (SD), orthogonal experimental design (OED) and inexact optimization modeling was proposed for water resources management under uncertainty. The developed method adopted a combination of SD and OED to identify key scenarios within multiple factors, through which interval solutions for water demands could be obtained as input data for consequential optimization modeling. Also, optimal schemes could be obtained in the combination of inexact two-stage stochastic programming and credibility constrained programming. The developed method was applied to a real-world case study for supporting allocation of multiple-source water resources to multiple users in Dalian city within a multi-year context. The results indicated that a lower credibility-satisfaction level would generate higher allocation efficiency, a higher system benefit and a lower system violation risk. The developed model could successfully reflect and address the variety of uncertainties through provision of credibility levels, which corresponds to the decision makers’ preference regarding the tradeoffs between system benefits and violation risks.

Urban energy consumption and related carbon emission estimation: a study at the sector scale

With rapid economic development and energy consumption growth, China has become the largest energy consumer in the world. Impelled by extensive international concern, there is an urgent need to analyze the characteristics of energy consumption and related carbon emission, with the objective of saving energy, reducing carbon emission, and lessening environmental impact. Focusing on urban ecosystems, the biggest energy consumer, a method for estimating energy consumption and related carbon emission was established at the urban sector scale in this paper. Based on data for 1996–2010, the proposed method was applied to Beijing in a case study to analyze the consumption of different energy resources (i.e., coal, oil, gas, and electricity) and related carbon emission in different sectors (i.e., agriculture, industry, construction, transportation, household, and service sectors). The results showed that coal and oil contributed most to energy consumption and carbon emission among different energy resources during the study period, while the industrial sector consumed the most energy and emitted the most carbon among different sectors. Suggestions were put forward for energy conservation and emission reduction in Beijing. The analysis of energy consumption and related carbon emission at the sector scale is helpful for practical energy saving and emission reduction in urban ecosystems.