An effective evaluation system can provide specific and practical suggestions to the deep groundwater management. But such kind of evaluation system has not been proposed in China. In this study, an evaluation index s...An effective evaluation system can provide specific and practical suggestions to the deep groundwater management. But such kind of evaluation system has not been proposed in China. In this study, an evaluation index system is specifically developed to evaluate deep groundwater management efficiency. It is composed of three first-level indicators(law enforcement capability, management ability, and management effectiveness) and eleven second-level indicators. The second-level indicators include seven mandatory indicators and four optional indicators. Piecewise linear function is used to normalize the quantitative indicators, and expert scoring method and questionnaire survey method are used to normalize the qualitative indicators. Then a comprehensive indicator weighting evaluation method is used to evaluate the first-level indicators and the target topic. A case study is carried out to evaluate deep groundwater management efficiency in Tianjin City. According to the evaluation score in each period, the management efficiency of every district in Tianjin City gradually improved. The overall evaluation score in the early deep groundwater extraction period is 0.12. After a series of deep groundwater protection efforts, this score reached to 0.61 in 2007, and met the regulation criteria. The evaluation results also showed that the further groundwater management efforts in Tianjin City should be focused on building a dynamic database to collect comprehensive deep well-log data; and on a reasonable design and distribution of the groundwater monitoring network. It demonstrated that the index system is suitable to locate the deficiencies of current groundwater management systems and to guide further improvements. It can then be used to protect deep groundwater.展开更多
With the completion of South-North Water Transfer Project in China, plenty of high quality water will be transported to Beijing. To restore the groundwater level in Beijing, part of transferred water is planned to be ...With the completion of South-North Water Transfer Project in China, plenty of high quality water will be transported to Beijing. To restore the groundwater level in Beijing, part of transferred water is planned to be used for artificial recharge. Clogging is an unavoidable challenge in the artificial recharge process. Therefore, a test is designed to analyse clogging duration and scope of influence and to test the reinjection properties of different recharge media. The test employs the self-designed sand column system with variable spacing and section monitoring, composed of four parts: Sand column, water-supply system, pressure-test system and flow-test system, to simulate the clogging of artificial recharge of sand and gravel pits. The hydraulic conductivity levels of all sand column sections are obtained to analyse the clogging of the injection of different concentrations in media of different particle sizes. In this experiment, two kinds of media are used–round gravel from sand and gravel pit in Xihuang village and the sand from sand and gravel pit by the Yongding River. The concentrations of recharge fluid are respectively 0.5 g/L and 1 g/L. The results show that clogging usually lasts for 20 hrs., and the hydraulic conductivity drops to the original 10%. Clogging usually occurs at 0–12 cm section of the sand column. The scope of influence is 0–60 cm. In column 3 and 4, whose average particle sizes are larger, section 20–50 cm also suffers from clogging, apart from section 0–12 cm. The effective recharge times are respectively 33 hrs. in column 1, 14 hrs. in column 2, 12 hrs. in column 3 and 12 hrs. in column 4. The larger the average particle size is, the quicker the clogging occurs. In media of larger particles, the change in suspension concentration does not have significant influence on the development of clogging. In conclusion, it is suggested that during artificial recharge, the conditions of reinjection medium should be fully considered and effective method of recharge be employed in order to improve effective recharge time.展开更多
There are many heterogeneous sensing nodes in the sensing layer of the Internet of Things, and the amount of data transmission is huge, which puts high requirements on the allocation of network bandwidth. At the same ...There are many heterogeneous sensing nodes in the sensing layer of the Internet of Things, and the amount of data transmission is huge, which puts high requirements on the allocation of network bandwidth. At the same time, untrusted sensing nodes maliciously invade network resources. Therefore, how to confirm whether a sensing node is trusted and reasonably allocate network resources is an urgent problem to be solved. To resolve this issue, this paper proposes a sensing network resource allocation model based on trusted groups. Through the sensing node computing environment and behavior measurement, we can identify and exclude untrusted nodes, so the trusted group can be built. Then the network resources are distributed from a global perspective. Based on the available bandwidth of the link, a network resource fusion model of IPv4 and IPv6 is proposed. On this basis, a global network resource allocation model is further proposed. Afterwards, real-time monitoring of data transmission behavior ensures data security during transmission. Simulation experiments show that this mechanism can effectively optimize the bandwidth allocation in the data transmission process and has little effect on the running efficiency of existing network applications. At the same time, it can effectively guarantee the trust of nodes and achieve trusted data transmission.展开更多
This paper aims to study the influence of the number and distribution of drill samples on the simulation accuracy of the lithology field. This research mainly applies the variation function method in geo-statistics, a...This paper aims to study the influence of the number and distribution of drill samples on the simulation accuracy of the lithology field. This research mainly applies the variation function method in geo-statistics, and determines important indicators such as the variation, and then the lithology field is simulated by sequence index simulation. It is shown that(1) simulation error decreases with the increase of sampling density;(2) at the scale and complexity of this study, when the sampling density reaches 40/km^2, the average error of the lithology field simulation can be less than 2.0%;(3) in the study mode of examples, the simulation results of random sampling in the whole region are the most ideal, with an average error of 5.4%. The average error of the simulation results of the centralized sampling is about 10 times that of the random sampling method;(4) known from the influence analysis of the degree of study sample unevenness influence on the imitation results, under the same sample size, the simulation error decreases with the increase of the most adjacent index. When the nearest index reaches 1, the simulation error will be less than 6%, and the error variable range is within 3%.展开更多
基金Under the auspices of National Basic Research Program of China(No.2010CB428804)
文摘An effective evaluation system can provide specific and practical suggestions to the deep groundwater management. But such kind of evaluation system has not been proposed in China. In this study, an evaluation index system is specifically developed to evaluate deep groundwater management efficiency. It is composed of three first-level indicators(law enforcement capability, management ability, and management effectiveness) and eleven second-level indicators. The second-level indicators include seven mandatory indicators and four optional indicators. Piecewise linear function is used to normalize the quantitative indicators, and expert scoring method and questionnaire survey method are used to normalize the qualitative indicators. Then a comprehensive indicator weighting evaluation method is used to evaluate the first-level indicators and the target topic. A case study is carried out to evaluate deep groundwater management efficiency in Tianjin City. According to the evaluation score in each period, the management efficiency of every district in Tianjin City gradually improved. The overall evaluation score in the early deep groundwater extraction period is 0.12. After a series of deep groundwater protection efforts, this score reached to 0.61 in 2007, and met the regulation criteria. The evaluation results also showed that the further groundwater management efforts in Tianjin City should be focused on building a dynamic database to collect comprehensive deep well-log data; and on a reasonable design and distribution of the groundwater monitoring network. It demonstrated that the index system is suitable to locate the deficiencies of current groundwater management systems and to guide further improvements. It can then be used to protect deep groundwater.
基金supported by National Natural Science Foundation of China(Nos.92166105,52005053,5180052032)High-Tech Industry Science and Technology Innovation Leading Program of Hunan Province,China(No.2020GK2085)+1 种基金Hunan Youth Science and Technology Innovation Talent Project,China(No.2021RC3096)Open Fund of Key Laboratory of New Processing Technology for Nonferrous Metal&Materials Ministry of Education,China(No.20KF-24)。
基金supported by public welfare geological investigation and scientific project of Beijing (2010): The key technology on clogging features analysis of groundwater artificial recharge
文摘With the completion of South-North Water Transfer Project in China, plenty of high quality water will be transported to Beijing. To restore the groundwater level in Beijing, part of transferred water is planned to be used for artificial recharge. Clogging is an unavoidable challenge in the artificial recharge process. Therefore, a test is designed to analyse clogging duration and scope of influence and to test the reinjection properties of different recharge media. The test employs the self-designed sand column system with variable spacing and section monitoring, composed of four parts: Sand column, water-supply system, pressure-test system and flow-test system, to simulate the clogging of artificial recharge of sand and gravel pits. The hydraulic conductivity levels of all sand column sections are obtained to analyse the clogging of the injection of different concentrations in media of different particle sizes. In this experiment, two kinds of media are used–round gravel from sand and gravel pit in Xihuang village and the sand from sand and gravel pit by the Yongding River. The concentrations of recharge fluid are respectively 0.5 g/L and 1 g/L. The results show that clogging usually lasts for 20 hrs., and the hydraulic conductivity drops to the original 10%. Clogging usually occurs at 0–12 cm section of the sand column. The scope of influence is 0–60 cm. In column 3 and 4, whose average particle sizes are larger, section 20–50 cm also suffers from clogging, apart from section 0–12 cm. The effective recharge times are respectively 33 hrs. in column 1, 14 hrs. in column 2, 12 hrs. in column 3 and 12 hrs. in column 4. The larger the average particle size is, the quicker the clogging occurs. In media of larger particles, the change in suspension concentration does not have significant influence on the development of clogging. In conclusion, it is suggested that during artificial recharge, the conditions of reinjection medium should be fully considered and effective method of recharge be employed in order to improve effective recharge time.
基金supported by the National Natural Science Foundation of China Research on Dynamic Trusted Running Mechanism of Io T Heterogeneous Nodes: 61971014The research of the trusted and security environment for high energy physics scientific computing system: 11675199
文摘There are many heterogeneous sensing nodes in the sensing layer of the Internet of Things, and the amount of data transmission is huge, which puts high requirements on the allocation of network bandwidth. At the same time, untrusted sensing nodes maliciously invade network resources. Therefore, how to confirm whether a sensing node is trusted and reasonably allocate network resources is an urgent problem to be solved. To resolve this issue, this paper proposes a sensing network resource allocation model based on trusted groups. Through the sensing node computing environment and behavior measurement, we can identify and exclude untrusted nodes, so the trusted group can be built. Then the network resources are distributed from a global perspective. Based on the available bandwidth of the link, a network resource fusion model of IPv4 and IPv6 is proposed. On this basis, a global network resource allocation model is further proposed. Afterwards, real-time monitoring of data transmission behavior ensures data security during transmission. Simulation experiments show that this mechanism can effectively optimize the bandwidth allocation in the data transmission process and has little effect on the running efficiency of existing network applications. At the same time, it can effectively guarantee the trust of nodes and achieve trusted data transmission.
文摘This paper aims to study the influence of the number and distribution of drill samples on the simulation accuracy of the lithology field. This research mainly applies the variation function method in geo-statistics, and determines important indicators such as the variation, and then the lithology field is simulated by sequence index simulation. It is shown that(1) simulation error decreases with the increase of sampling density;(2) at the scale and complexity of this study, when the sampling density reaches 40/km^2, the average error of the lithology field simulation can be less than 2.0%;(3) in the study mode of examples, the simulation results of random sampling in the whole region are the most ideal, with an average error of 5.4%. The average error of the simulation results of the centralized sampling is about 10 times that of the random sampling method;(4) known from the influence analysis of the degree of study sample unevenness influence on the imitation results, under the same sample size, the simulation error decreases with the increase of the most adjacent index. When the nearest index reaches 1, the simulation error will be less than 6%, and the error variable range is within 3%.
