abstract
Firstly, this paper investigates the water shortage in Beijing from 200 to 2009.
Attribute and other risk processes, the weight of each water shortage influencing factor in Beijing is quantitatively divided by AHP model.
Based on risk factors, risk-taking factors and hazard degree, the risk evaluation index of water resources system is constructed.
And model: the index system consists of 20 indexes in 4 levels, which can better represent the generation and composition of risks; should
The model includes parameter calculation and risk classification, which can easily calculate the classification of risk grade. Secondly, this paper comprehensively considers water.
The results show that Beijing can cope with the risk of water resources system, but it is still limited by binding risks.
We can deal with it by increasing revenue and reducing expenditure, adjusting industrial structure and planning water resources management. Then we do a survey of Beijing 200 1-2009.
The total annual water resources, surface water resources and groundwater resources were investigated. Using Matlab processing system to check the calendar
The annual precipitation is fitted, and the water consumption of ten thousand yuan GDP is fitted by origin processing system, and the water shortage is obtained.
The conclusion that the quantity fluctuates greatly. Finally, this paper upgrades and perfects the established model, and adopts the establishment and modification of grey model.
By solving the unbiased GM( 1, 1) model, the annual risk rate (RBI) and risk acceptance rate (RBI) of 201year and 201year are obtained.
Rate (RSI), vulnerability (CI), risk (ωωDRi) and risk loss (DI), and draw the conclusion of Beijing.
The risk of water shortage in the next two years will be 28.40% and 30.50%, respectively, showing an upward trend and increasing year by year.
But it is basically within the bound risk level. Therefore, it is suggested that management agencies limit the use of water resources to prevent wind.
Risk, by recommending efficient water resources system management, promoting the process of optimal allocation of water resources and other ways to promote water resources system.
Recovery, effectively reduce the occurrence of risks and potential damage.
Keywords: Analytic Hierarchy Process Multiple Regression Fitting Unbiased GM( 1, 1)
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1. Restatement of the problem
Water resources refer to natural water bodies that can be directly utilized by human beings and can be continuously renewed. Mainly including land on land.
Surface water and groundwater. In recent years, the shortage of water resources in China, especially in the northern region, has become increasingly serious, and water resources have become
Focus topic. The risk of water resources system is due to the fluctuation of natural incoming water, insufficient sustainable guarantee capacity of groundwater and water supply lines.
The backwardness of water resources and the heavy social and economic burden are the comprehensive results of negative impacts on society, economy and environment.
There is potential damage. At present, Beijing is one of the metropolises with a serious shortage of water resources in the world, and the per capita water resources are available.
Less than 300m3, it is 1/8 of the national average and 1/30 of the world average, and it is a serious water shortage area in Beijing.
Shortage has become the main factor affecting and restricting the social and economic development of the capital. The government has taken a series of measures, such as south
Construction of South-to-North Water Transfer Project, establishment of sewage treatment plant, adjustment of industrial structure, etc. However, climate change and economy and society remain unchanged.
The risk of development and water shortage always exists. How to identify the main factors of water resources risk and cause the risk
Divide the risk levels and take corresponding effective measures to avoid risks or reduce risks caused by different risk factors.
Harm, which is of great significance to social and economic stability and the implementation of sustainable development strategy.
According to Beijing Statistical Yearbook 2009 and municipal statistical data, the relevant information of water resources in Beijing is provided. profit
Using these data and other data obtained by ourselves, we discussed the main reasons of water shortage in Beijing.
Because it is the contradiction that the supply of water resources is less than the demand, and to solve this problem, we must start with the influencing factors.
Child, so this problem is subdivided into:
What are the main factors of water shortage in Beijing?
What is the contribution of each factor to the degree of risk?
What kind of risk has Beijing reached?
How to deal with the main factors to reduce risks and achieve effective supervision?
To what extent will Beijing face the risk of water shortage in the next few years and how to deal with it?
Finally, through a series of processes such as modeling, analysis and testing, we draw a conclusion and write a letter to the competent department of Beijing.
Proposal report.
2. Problem analysis
Beijing's per capita water resources rank behind the world's 100 capitals. Since the 1970s,
With the large increase of population and economic development, water shortage has become one of the serious problems facing Beijing, and it has been in short supply every year in recent years.
The water volume is about 400 million cubic meters. The exploitation of groundwater resources is increasing rapidly year by year, although the exploitation of groundwater is limited at present.
System, the groundwater level has risen, but it is still in the state of over-exploitation. Overexploitation of groundwater will form a funnel area. So far,
With Chaoyang District as the center, it reaches Shijingshan in the west, Shunyi in the east, Nanyuan in the south and Changping in the north, with an area of about 1600 square meters.
Kilometers of funnel area, causing ground subsidence. As the water level continues to drop, the well is drilled deeper and deeper, forming a vicious circle.
In view of this situation, for many years, Beijing has not only adjusted its industrial structure, but also ensured the safety of water supply in various ways.
Vigorously save water, raise water prices many times, vigorously promote water conservation in agriculture, industry and cities, and close, shut down and transfer high-water-consuming enterprises.
Outside the industry, it has also created a six-water joint regulation mode of surface water, groundwater, reclaimed water, transit water, rain and flood, and external water transfer.
Rational allocation of water resources can improve the city's water supply capacity. Although the method has been exhausted, what is it?
What caused the present situation in Beijing? Is there any reason and how to solve it? After discussion among the members of the group,
Looking for information and intense discussion, we think that from the perspective of water resources system structure, risks come from system attributes and processes.
Weak resistance to potential dangers. The shortage of input subjects, process fluctuation and the output fragility of the system itself are the leading factors.
The important reason of risk is that they are the risk-causing factors of water resources system risk; Risk factors of water resources system
Feedback, guide the system to resist potential risks, so as to reduce risks and harm, we will this kind of anti.
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Feed-in resistance is called risk tolerance; Under the interaction of risk-causing factors and risk-bearing factors, when the risk-causing pressure is greater than the risk-bearing pressure,
Risk ability, risk is generated. Therefore, risk factors are divided into risk-causing factors and risk-bearing factors, and then divided into risk-causing factors and risk-bearing factors.
Risk factors will be subdivided into many articles. Different factors have different contributions to risk. this
Excel or Matlab and origin software can be used to calculate in a modeling way, and then the system can calculate.
Setting a risk level will show the present situation of Beijing and make reasonable regulation on the factors that contribute greatly.
As for the prediction of water shortage in Beijing in the next two years, we can use the idea of regression and then use the grey theory to further.
After the improvement, Beijing is predictable.
3. Assumptions and symbols of the model
Assumption 1: There is little difference between the actual values of water resources collection data in Beijing;
Hypothesis 2: The influencing factors will not change suddenly due to unexpected events;
Hypothesis 3: the data collected by modeling is true and reliable;
Hypothesis 4: the conclusions involved in subjective analysis in modeling are basically consistent with the facts;
Aij- 1-9 The relative importance of item I relative to item J obtained by scaling theory.
μij- measurement judgment value
Ω Ω d-the relative weight vector at the standard level D.
Ci- vulnerability
Ω Ω Si —— the index weight of the occurrence and transmission of system risk to the system damage rate in the relevant evaluation index system.
Redistribution value of
Pi-the potential occurrence probability of risk
Ri-the index value of system risk coefficient.
Risk loss
RBI- risk rate
RSI- risk bearing rate
ωdri- risk
B- regression coefficient;
Bint interval estimation of regression coefficient;
R- residual;
Rint- confidence interval;
Stats- statistical data used to test the regression model, with three values: correlation coefficient r2, F value and F pair.
The closer the correlation coefficient r2 is to 1, the more significant the regression equation is.
F> Reject H0 when F 1-α(k, n-k- 1), and the larger f is, the more significant the regression equation is. Use F.
The corresponding probability p α
The α-significance level is generally 0.05 or 0.0 1, which is 0.05 in this paper.
4. Model establishment and solution
Question 1 4. 1:
We investigated and compared the total annual water resources and the total annual water supply (water consumption) in Beijing, as shown in Table 1.
Show.
four
Table 1
[7]-[9]
200 1 2002 2003 2004 2005 2006 2007 2008 2009
The total annual water resources are19.216.18.421.423.224.523.834.221.8.
The annual total water supply (water consumption) is 38.9 34.6 35.8 34.6 34.5 34.3 34.8 35.135.5.
Total annual water resources and annual water supply (water consumption) in Beijing
Comparison of
19.2
16. 1
18.4
2 1.4 23.2 24.5 23.8
34.2
2 1.8
38.9 34.6 35.8 34.6 34.5 34.3 34.8
35. 1 35.5
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
200 1 2002 2003 2004 2005 2006 2007 2008 2009
Total annual water resources
Total annual water supply (water consumption)
Billion cubic meters
The 3D orthographic map processed by Origin software is shown in figure 1.
Figure 1
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As shown in the figure, the total annual water supply in Beijing is higher than the total water resources. Since Beijing hosted the Olympic Games in 2008,
In order to ensure the timely supply of water resources in Beijing, there is little difference between the water supply and the total water resources.
noodle The data of other years reflect the water shortage in Beijing all year round.
We characterize the system presentation layer by specific system attributes and system potential damage indicators. Through the water
The research on the circulation mechanism of cultural water resources fully considers the risk generation and transmission mechanism of water resources system. Through layer-by-layer screening,
So as to get the following 20 evaluation indicators (as shown in Figure 2).
[ 1]
.
Fig. 2 risk assessment index system diagram of water resources system
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Description:
A represents the target layer, that is, the target of water resources system risk assessment, that is, water resources system risk assessment.
Count.
B represents the risk attribute layer, that is, the generation and transmission of the risk tolerance of the hidden danger elimination system.
Cheng. The risk attribute layer is short, volatile, fragile and risk-bearing. The risk tolerance of the system depends on water.
The risk of resource system is expounded.
C stands for the presentation layer of risk attribute system, that is, the comprehensive presentation layer of water resources system facing risks, but it cannot
Clearly characterize the risk of the system, so it is necessary to evaluate the potential risk and damage degree of the system.
To perfect the characterization. The index system reflects the risk attribute layer through 12 index.
D stands for evaluation index layer, that is, the system table is evaluated through specific system attributes and system potential damage indicators.
Feature layer for characterization. Through the research on the circulation mechanism of hydrology and water resources, the wind of water resources system is fully considered.
The mechanism of risk generation and transmission, through layer-by-layer screening, draws the following 20 evaluation indicators. These indicators
The risk of water resources system is not only manifested in quantity and quality, but also in social, economic,
The influence of ecological environment, and comprehensively consider people's active adaptation to risks and people's emergency treatment.
Subjective initiative.
We believe that from the perspective of water resources system structure, the risk comes from the system attributes and the process's resistance to potential hazards.
Fatigue. Kaplan and others defined risk from a quantitative perspective [2]
, the system itself lacks input subjects, process waves.
Dynamic vulnerability and output vulnerability are important causes of system risk, and they are the risk causes of water resources system risk.
Son; The water resources system feeds back risk factors and guides the system to resist potential risks, thus reducing risks.
Health and harm, we call this feedback and resistance nature risk tolerance; The system is in the relationship between risk-causing factors and risk-bearing factors.
Under the influence, when the risk-causing pressure is greater than the risk tolerance, the risk arises. The elements of water resources system risk also include losses.
The risk process under the comprehensive action of damage degree, hazard pressure, risk tolerance and damage degree is shown in Figure 3 [1].
.
Figure 3 Risk process and attribute characterization of water resources system
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System risk factors (as shown in Figure 2) can be summarized as risk-causing factors and risk-bearing factors. The former refers to system changes.
The change of system structure and external interference make the probability of risk become risk rate; And the latter is
Refers to the elements that can cope with hazards through full feedback from the system or self-adjustment and adaptation after historical accidents.
The ability to reduce risks is the risk-taking rate. Let's discuss risk factors and risk-taking factors.
Risk factors of water resources system:
① Shortage: refers to the nature that the input subject of water resources system is easily damaged during its own operation.
It represents the incompleteness of the input subject of the system to resist risks. The shortage is reflected in the fact that the supply and demand of system operation are not met.
And the extent to which the system was destroyed. Specifically, the shortage of water resources system is reflected in the underutilization,
Insufficient water storage and environment, namely water shortage rate, groundwater overexploitation and water pollution.
Damage.
② Volatility: Relative to the stability of normal operation of water resources system for many years, volatility refers to water resources.
The essence of unbalanced operation of the system caused by system fluctuation or factor fluctuation. System fluctuation comes from the system.
The imbalance of the system for many years and the variability of input and output of the system. Fluctuations can be expressed by average state and extreme difference.
At the same time, the stability of system input and output is also very important. Therefore, the fluctuation of water resources system is transformed from years of fluctuation.
Dynamic, extreme fluctuation and water source fluctuation.
(3) Vulnerability: indicates the potential damage degree of the risks faced by the system, that is, the vulnerability of the potential output of the system to resist risks.
Weakness.
Vulnerability index can measure the degree of damage caused by risk, which is reflected in the coupling degree between water resources and social economy.
In the integrated system, it mainly causes the decline of social, economic and ecological ability to cope with risks. Social losses are reflected in per capita potential.
The loss of utilization ability and economic loss represent the damage to production activities, while ecological damage is reflected in the ecological environment.
Damage to the environment.
Risk factors of water resources system:
The water resources system itself is a dynamic and open system, which can cope with risks through its own feedback adjustment.
The system itself has formed a set of risk-taking factors system to take risks and prevent them from being destroyed. The resources of the water resources system itself
The resource endowment, the adaptability of the system to the formation of risk events, and the emergency of manual scheduling when risks occur.
It is a powerful guarantee for the system to cope with risks, and it is also a risk-taking factor for the water resources system. Resource endowment is embodied in the water resources system itself.
Have resource conditions, such as water resources guarantee and water resources regeneration conditions; Adaptability refers to human production in a long period of time.
Measures and methods to deal with risks formed in activities, including water-saving measures and the formation of water-saving consciousness, as well as water
Strive to optimize resource management and improve efficiency; And emergency is formed by human beings in response to risks.
Ability of emergency management and dispatching measures [1]
.
To sum up, we judge that the main risk factors of water shortage risk in Beijing include risk-causing factors and risk-bearing factors.
The risk factors of water resources system are embodied in three aspects: utilization, water storage and environment, namely water shortage rate and groundwater.
Over-exploitation of water and water pollution cause damage. Risk-taking factors are reflected in the resource endowment of the system itself and the internal risks of the system.
The adaptability of event formation and the emergency of manual scheduling when risks occur.
4.2 For Question 2:
We believe that in order to distinguish the main influencing factors of water shortage and plan and manage Beijing in a targeted manner,
We use analytic hierarchy process (AHP) model for quantitative analysis.
Analytic Hierarchy Process (AHP) is a decision-making method combining quantitative and qualitative methods.
Method. Analytic Hierarchy Process (AHM) is a simplification and improvement of analytic hierarchy process. Relatively speaking.
Speaking of it, AHP has higher requirements for consistency. The core of AHM is to judge the scale matrix in AHP.
(aiji) n * n is converted into a measure judgment matrix (μ ij) n * n, and the conversion formula is:
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Where: aij is the scaling theory according to 1-9, and the relative importance of item I relative to item J; Generally take β=2. AHM
The method for determining the weight mainly comprises the following steps:
① According to the scaling theory of 1 ~ 9, the pairwise comparison matrix is constructed, that is, the judgment matrix A = (μ ij) n * n
② According to the conversion formula, construct the measure judgment matrix of AHM, and check the consistency line by line.
③ attribute AHM replication method: compare the relative importance of n indexes Dj(j= 1, 2, …n) and determine each one.
The weight of each index can be realized by constructing the judgment matrix of relative attribute measure. Let μij mean that the i-th index is relative.
The importance of j index; μji indicates the importance of the j-th indicator relative to the i-th indicator. μii means.
Comparison of the i-th index itself. According to the requirements of attribute mathematics, μii=0, μij+μji= 1. The structure is as follows.
AHM model in which n*n elements μij form a relative attribute measure evaluation matrix (μ ij) n * n
④ Each column of the normalized measure judgment matrix:
⑤ Find the sum of the elements in each row of the judgment matrix:
⑥ Normalization of corresponding vectors:
Ω I is the relative weight of each factor at this level relative to a factor at the previous level. In the specific application, under a certain standard D,
The relative weight vector between elements is expressed as:
D ω =( 1
f
ω , 2
f
ω，…，f
n ω)
Where [1]
：
nine
The transmission of risk follows the transmission principle of system science [3]
The transfer function of parallel system is the transfer function of two subsystems.
That is, the sum of numbers
ωs= ωs 1 ﹢ωs2
Where ωs 1 and ωs2 are subsystems 1 and 2, respectively.
We combine the risk function, that is, the above formula, and according to the evaluation index system, this paper will establish the results based on system attributes and transmission.
The risk assessment parameters of water resources system include risk rate, risk acceptance rate, vulnerability and risk loss.
Tobin and Montz proposed to measure risk by the product of risk probability (Pi) and system vulnerability. This model
It is found that this kind of risk result is an important embodiment of risk loss in construction, so this method is adopted to establish comprehensive
The combined risk damage parameter DI represents the risk, as shown in the following formula:
Through the index system, it will reflect the risk rate of the system facing risk factors and risk-taking factors.
(RBI)
And RSI are calculated as follows:
14
1
Di I
I
RBI R ω
=
=∑ ?
20
15
Di I
I
RSI R ω
=
=∑ ?
After calculation, the index value Ri of the system risk factor (see Table 2), the contribution of the system risk factor to the system,
That is, the system risk weight ωD (see Table 3).
Table 22001-Risk Index Value (Ri) of Beijing Water Resources System in 2009
Indicator d1d2d3d4d5d6dD7 d8 d9d10
Li1.0000 0.3500 0.1751.0000 0.49291.0000 0.1917 0.6923 0.7300 0 0.
Indicator d112d13d14d15d16d17d19d20.
Li 0.1039 0.0493 0.7586 0.4020 0.6684 0.210.1086 0.8700 0.2354 0.3000
In the risk assessment index system of water resources system, the vulnerability factor of water resources system not only represents the occurrence of risk.
Risk factors reflect the damage degree of water resources system. Therefore, when characterizing the degree of damage, it is necessary to construct.
The damage characterization parameters, namely vulnerability and index weight, which are different from disaster tolerance are established.
Index weight ωD of insurance system.
10
14
nine
Si i
I
CI R ω
=
=∑ ?
Among them, ωsi refers to the occurrence and transmission of system risk to system damage rate in relevant evaluation index system.
Redistribution value of bid weight (see ωS in Table 3).
Table 3 Weight of Risk Assessment Indicators of Beijing Water Resources System
Indicator d1d2d3d4d5d6dD7 d8 d9d10
ωD 0.2440 0.6609 0. 1567 0.0267 0.0457 0.0770 0.0 164 0.07 10 0 0.0468 0.0300
ωS 0.2606 0.0963
Indicator d112d13d14d15d16d17d19d20.
ωD 0. 1090 0. 1690 0.0 130 0.0890 0.3880 0. 1935 0.2576 0.05 15 0.09 10.0 19 1
ωS 0.254 1 0.0958 0.07 15 0.22 14
When calculating risk, the product of risk potential probability (Pi) and vulnerability (CI) is used.
The square root ωDRi (risk index) represents risk [1]
：
00
Data input (British) Defence Inteligence)? Density Indicator (density indicator)
Didi
rare
Defense intelligence department
ω
& gt？
= ?
≤
Combined with the situation of Beijing water resources system, the risk assessment index of Beijing water resources system in 200 1- 2009 is obtained.
According to the index value, the risk rate (RBI) and risk bearing rate of Beijing water resources system can be obtained by using the above formula and Excel software.
(RSI), vulnerability (CI), risk (ωωDRi) and risk loss (DI) were 57.63%, 40.05% and 42.46% respectively.
27.3%、7.46% 。
Refer to American military standard (MIL-STD-882)[4]
According to the risk definition in this paper, the qualitative analysis method provided in
The relationship between risk factors and system risk tolerance is fully considered, and the risk of water resources system is divided.
Level 5 represents different risk levels, as shown in Table 4.