Guarantee Rate Research Articles

Research on multi-objective optimal allocation of regional water resources based on improved sparrow search algorithm

Abstract Nowadays, the conflict between the supply and demand of water resources in many regions is becoming increasingly prominent. Scientific allocation of regional water resources has become the key to solving the contradiction. In this study, a regional multi-objective water resources optimization allocation model considering social, economic, and ecological objectives is established, and four improvement spots are introduced to the sparrow search algorithm (SSA) to form an improved sparrow search algorithm (ISSA). By testing nine benchmark functions including monotonic and multi-peaked, the search efficiency and average convergence results of ISSA are significantly enhanced compared with other intelligent algorithms. Meanwhile, this research uses Luanchuan County, Henan Province, China, as an example to solve the water resource allocation scheme for 2025 and 2030 in the region using ISSA. The results show that the overall water shortage rate decreases to 3.49 and 2.79%, respectively, under the 75% guarantee rate, resulting in an effective reduction in future water shortages. Simultaneously, the scheme proposed has sound comprehensive benefits and can provide important technical support for the refined management of water resources, which is a reference and guidance for solving the contradiction between water supply and demand at the current stage.

Distribution Features of Deviation and Determination of a Tolerance Method for Prefabricated Concrete Components

According to the current standards for prefabricated buildings, the dimensional tolerances of components are usually determined by experience, lacking a theoretical basis. This work demonstrates the mathematical distribution of the dimensional deviations of precast concrete components by measuring their three-dimensional dimensions. Utilizing the Kolmogorov–Smirnov test, the cumulative distribution function of dimension deviations was evaluated. In response to the fact that the tolerance division principle of equal upper and lower tolerance thresholds for prefabricated components in existing standards does not match the distribution of actual measured deviations of the components, this paper proposed a method for determining the tolerance values of prefabricated components based on the process capability index. The association between the process capability index and the qualification rate was utilized to determine the process capability index at a specified guarantee rate, which, in turn, determines the tolerance threshold values for various components. The results indicate that the range of unqualified random variables for the dimensional geometric parameters of the prefabricated components did not show a significant difference, with all values between 0.99 and 1.02. The coefficients of geometric parameter variation were all less than 0.0061, and the component dimensional deviation adhered to the normal distribution. By linking the process capability index with the pass rate, a process capability index of 0.55 at a guarantee rate of 90% was determined, along with the tolerance for various components.

Application of Photovoltaic Systems in Field Observation and Research Stations: Research on the Relationship between Power Generation Scale and Electricity Consumption to Improve Photovoltaic Application in Field Observation Stations

Most field scientific observation and research stations are located at the end of power grids which are usually not extended to such areas. Consequently, the power supply of equipment in field observation stations cannot be guaranteed. Meanwhile, regions with poor ecosystem stability are relatively sensitive to environmental changes and thus prone to degradation and succession due to external interference. In this paper, the photovoltaic (PV) power generation system of a grassland ecohydrological field scientific observation and research station was taken as the research object. Two kinds of distributed PV power generation systems were simulated and analyzed by use of PVsyst software. The total power of laboratory equipment, PV power generation efficiency, and system cost of the field observation station were calculated and analyzed. The design scheme and scale of PV power generation systems suitable for field observation stations were determined. Finally, a PV power generation test system was set up, and PV power generation data were sorted out. The feasibility of the design scheme of PV power generation systems was verified by analyzing the relationship between the simulated and actual power generation of systems and that between the daily energy use proportions of field observation stations. Besides, the environmental benefits of PV systems were analyzed, and their amount of energy saving and emission reduction was calculated. This study can solve the issue of the low power supply guarantee rate of field observation stations, provide a design basis and beneficial reference for the construction of environment-friendly field laboratory stations, and realize green energy saving and the sustainable use of energy while protecting the ecosystem from being destroyed.

Measurement of water resources carrying capacity in Gugang Town of Central China based on human-water-agriculture framework

More research has revealed that central China is one of the most vulnerable areas to a water crisis because of limited and unequally distributed water resources as well as rising water demands. Also, climate change is expected to reduce water resources dramatically, resulting in increased competition among users and severe water shortages for irrigated agriculture. The township, the most basic level of the Chinese government system, urgently needs to compare water allocation based on different management strategies to define the most optimized water management plan. The concept of a “human-water-agriculture” evaluation system was proposed in this study to couple and coordinate human well-being, sustainable water resource use, and agricultural development in Gugang Town, China. Within this framework, twenty-five indicators were chosen from the criterion layers to assess and optimize the carrying capacity of water resources for historical periods and the future year 2030. The results showed that the WRCC was bearable in previous years, except for 2018 when the percentage of water shortage reached 19.5 % because of a sharp reduction in dynamic surface water availability. The static surface water, represented by the water restored in hilly ponds in village and town areas, was discovered to account for up to 17 % of the total amount for the dry year. The WRCC would be overburdened in 2030, with 61.6 % and 18.1 % water-deficient underwater supply at 90 % and 75 % guarantee rates, respectively. The WRCC states that effective optimization of agricultural water allocation for crops to maximize economic benefits with limited water consumption could significantly improve human and agricultural systems. This study investigated a route for studying WRCC in village and town areas, providing theoretical and practical guidelines for local water-adapted development.

Study on the seismic influence coefficient of track irregularity on the train dynamic effect of high-speed railway bridge

Track irregularity is an important factor affecting the train-track-bridge system interaction, and for the seismic design of the track-bridge system, the study of the law of the influence of track irregularity on the train dynamic effect is of great theoretical significance. Based on this, the finite element models of China railway track structure (CRTS) II plate high-speed railway simple-supported girder bridge and CRH2C high-speed train model are developed and compared with the shaking table test results to verify their validity. Considering track irregularity and earthquake randomness, a sample library of the train dynamic effect of the track-bridge system under earthquake is established, the probabilistic statistical characteristics of the train dynamic effect are analyzed, and the influence level of track irregularity on the train dynamic effect of the track-bridge system under earthquake is studied, and the standard value of track irregularity influence coefficient of train dynamic effect based on probability guarantee rate is proposed. The results indicate that: the influence of track irregularity on the seismic response of bridge structure is slight, with their greatest impact not exceeding 1%. However, it has a significant impact on the seismic response of track structures. The standard values of the sliding and mortar layers’ track irregularity influence coefficients are 1.49 and 1.71, respectively, at 0.1 g. Under various peak ground acceleration (PGA) settings, the fasteners’ standard values for the track irregularity influence coefficient are less than 1.1. Additionally, the degree of influence of track irregularity on the seismic response of track structure decreases significantly as the PGA increases.

Study on Optimal Operation of Inter-Basin Water Transfer Project Considering Uncertainty of Hydrological Forecast based on Multi-Objective Optimization Method

The shortage of water resources has become an important factor restricting economic and social development, and optimizing the inter-basin water transfer project is the key to solve the shortage of water resources. The purpose of this paper is to study the optimal operation of inter-basin water transfer project based on multi-objective optimization method considering the uncertainty of hydrological forecast. In this paper, a multiple linear regression algorithm is proposed. Based on this study, the experimental results of optimal operation of interbasin water transfer projects based on the uncertainty of hydrological forecast are analyzed. The experimental results in this paper show that the overall change of the forecast optimal dispatch chart considering the uncertainty of hydrological forecast is similar to the traditional optimal dispatch chart, the difference is that it incorporates hydrological data into the forecast, so that the current available water can be more accurately grasped. Therefore, in the flood season, the division of the guaranteed output area and the increased output area is clearer and more reasonable. Moreover, the forecast optimization dispatching chart considering the uncertainty of hydrological forecast can effectively improve the calculation of guarantee rate, which is of great significance to solve the urban water supply problem.

Analysis of Impact of Well-Facilitated Farmland Construction—Engineering Measures on Farmland Quality

We studied the influence and correlation of soil improvement, farmland ecological protection, soil fertilization, and field infrastructure construction on the quality grade of well-fertilized farmland in the engineering measures of well-fertilized farmland construction. Taking Xiao County of the Anhui Province as the study area, based on the software platforms of SPSS, ArcGIS10.6, and the county farmland resource management information system, we investigated the farmland quality changes of well-facilitated farmland before and after construction using the fuzzy evaluation method and analytic hierarchy process. We used principal component analysis and the gray relational method to analyze the impact and correlation of various engineering measures on farmland quality. The farmland quality grade in the study area was improved by a 0.59 grade after the construction of the well-facilitated farmland. Well-facilitated farmland construction engineering measures mainly affected the farmland quality through 12 factors, such as the soil bulk density, tillage layer texture, irrigation and drainage guarantee rates, forest network density, and field road accessibility. There is a strong correlation between these factors and the characteristics of farmland quality; the degrees of correlation were 0.865–0.610, respectively. The highest correlation degree was 0.939 between the deep plowing and deep loosening soil improvement project and the improvement of the well-facilitated basic farmland quality; this was followed by soil fertilization with an increased application of organic fertilizer, farmland ecological protection, and the field infrastructure project with correlations of 0.936, 0.857, and 0.563, respectively. Represented by the improvement of farmland fertility, the soil improvement project had the strongest impact on well-facilitated farmland quality. The soil fertility project, farmland ecological protection project, and the field infrastructure project were the second most important, with very close degrees of correlation.

Storage allocation rules to meet shared water demands for optimal operation of reservoir water supply

AbstractThe priority principle of storage allocation rules of serial cascade reservoirs within an interbasin water supply can reduce water loss and reduce water supply times. Reasonable balancing curves for reservoirs in parallel are proposed, and the proportional distribution of water is determined to illustrate the optimal allocation rule for different reservoir scheduling periods. The mutation point and slope are used to describe the segmentation of reservoirs in parallel. Finally, the relative optimal water supply rule is obtained. Taking the reservoir groups in the lower reaches of the Luanhe River basin as the research object, the results show that the water supply obtained by the balancing curve is increased by approximately 4% compared with the compensation regulation, and wasted water is reduced by 10%. The results are close to the largest water supply, the annual average wasted water and the guarantee rate obtained by dynamic programming. The suggested method can achieve the operation goal effectively and improve the operation performance of the shared water demands for the reservoir water supply. This article highlights the superior results obtained compared with the current storage allocation rules to meet shared water demands.

Study on power spectral density curves of track dynamic irregularity caused by earthquake-induced damage

A series of studies on track dynamic irregularity caused by earthquake-induced damage should be conducted in order to guarantee safe operation of high-speed trains. In this study, a nonlinear time history analysis of high-speed railway CRTS Ⅱ track-bridge system under transverse random earthquakes is carried out, and the post-earthquake stiffness degradation degree of main components of track-bridge system is analyzed. A three-dimensional coupled vibration model of train-track-bridge system based on earthquake-induced damage is established, and a sample library of earthquake-induced track dynamic irregularity is constructed. Kolmogorov-Smirnov method is used to test the normal distribution of earthquake-induced irregularity samples. A calculation method of the earthquake-induced dynamic irregularity power spectral density curves based on probability guarantee rate is proposed. The power spectral density curve is fitted by piecewise polynomial, and the influence of train operation speeds and peak ground accelerations (PGAs) on the power spectrum of earthquake-induced dynamic irregularity is analyzed. The results demonstrate that the degradation degree of piers and bearings of the track-bridge system under transverse random earthquake presents the characteristics of large in the middle and small on both sides. The earthquake-induced track directional irregularity samples follow the normal distribution. The shape of the power spectral density curve has obvious segmentation characteristics in the double logarithmic coordinate system. The power spectrum amplitude decreases significantly with the increase in spatial frequency and fluctuates significantly in the high frequency band. There are little influence of the train operation speeds on the power spectrum curves. In contrast, the influence of the PGAs on the power spectrum is significant. The amplitude of the power spectrum increases obviously as the PGA increases.

Study on the performance of an ultra-low energy building in the Qinghai-Tibet Plateau of China

The ultra-low energy building is an effective solution to reduce building energy consumption and CO2 emission in high-cold and high-altitude areas of China. A new ultra-low energy building in the Qinghai-Tibet Plateau was built, and a solar-air source heat pump system was designed to cover the heating needs in winter. The performance of the ultra-low energy building was studied by measurement and simulation methods. The measured results show that the average room temperature is above 18 °C without heating, and the indoor temperature can meet the requirements of 20 °C with the heating system. The indoor VOC concentration can be maintained at a low level. The building's air tightness can meet the requirements of the ultra-low energy building. The heating system ran well, and the average COP was 2.6. The simulation results show that the natural room temperature is between 20 and 23 °C more than 90% of the time under heating conditions. The average COP of the heat pump is 3.6, and the solar energy guarantee rate is 44.8% throughout the heating season. The heating system can save 2490.5 kg of standard coal and 6724.3 kg of CO2 emission per year.

Evaluation and Analysis of Grain Production Capacity of High-standard Farmland Construction

High-standard farmland construction is an important way to protect the quality of cultivated land and improve grain production capacity in the new era, and also an important starting point for the practical implementation of the new urbanization construction and rural revitalization strategy. The evaluation and identification of grain production capacity depends on the results of farmland grade evaluation and demonstration, while the grading factors selected for designated crops, such as effective soil layer thickness (cm), surface soil texture, soil salinization degree, soil organic matter content (g/kg), drainage conditions, terrain slope, irrigation guarantee rate and irrigation water source, have a significant impact on farmland grade evaluation. This paper analyzes the new grain production capacity generated by the construction of high standard farmland in a county. After the construction of high standard farmland project, the cultivated land grade in the project area can be increased by 1 grade, and the new grain production capacity is estimated to be 3000 tons. The research method can provide necessary reference for the implementation of similar projects.

Analysis of the influence of CA mortar layer void on the dynamic performance of high-speed trains

The void of cement asphalt (CA) mortar layer will aggravate the abnormal vibration of high-speed trains at the void position and threaten the running safety. Few studies have been conducted on the effect of mortar layer void on the dynamic performance of slab track on bridges and the damage limits. Aiming at the practical problem of CA mortar layer void in track-bridge systems, a dynamic response calculation program for the train-track-bridge system is prepared based on the train-track-bridge interaction theory. A sample library of high-speed trains running performance indicators considering random initial track irregularity under CA mortar layer void conditions is constructed. The influence of void length on the dynamic performance of high-speed trains under two different CA mortar layer void conditions is investigated by means of sample upper bounds based on probability guarantee rate. The results show that the wheel load reduction rate and vertical acceleration of high-speed trains are more sensitive to changes in void length than the derailment coefficient. The effect of CA mortar layer void on the running performance index of high-speed trains is significantly enhanced after a certain critical void length value, railway maintenance should pay more attention to critical thresholds. The mid-span void and beam-end void length thresholds of CA mortar layer based on the probability guarantee rate decrease significantly with the increase in running speed while utilizing the wheel load reduction rate as the control index. However, the void position has little influence on the void length threshold. The void length threshold results can provide a basis for the CA mortar void limits.

Cropland: Surplus or Deficit? From the Perspective of Meeting People’s Grain Requirement

The quantity and quality of cropland plays an important role in ensuring food security. In order to explore spatiotemporal patterns of the extent to which cropland satisfies people's grain need, we integrate multi-source heterogeneous data to investigate in which era, and in which region, the cultivated land can meet people's food demands. It turns out that in the past 30 years, with the exception of the late 1980s, the amount of cropland could satisfy people's grain needs at the nation scale. However, more than 10 provinces (municipality/autonomous region), mainly located in western China and southeast coastal areas, have been unable to meet the grain needs of local people. We projected the guarantee rate to the late 2020s. Our study concludes that the guarantee rate of cropland is estimated to be higher than 150% in China. Compared to 2019, except Beijing, Tianjin, Liaoning, Jilin, Ningxia, as well as Heilongjiang in the Sustainability scenario, and Shanghai in the Sustainability and the Equality scenarios, the guarantee rate of cultivated land will increase in every province (municipality/autonomous region) in 2030. This study has reference value for the study of China's cultivated land protection system, as well as important significance for China's sustainable development.

Influence of damping on seismic-induced track geometric irregularity spectrum in high-speed railway track-bridge system

Track irregularities are an important factor affecting the safety, smoothness, comfort, and lifespan of high-speed railway track structures. Damping greatly affects the seismic response, and the influence of damping on seismic-induced track geometric irregularities is of significant interest. In this study, the simple-supported beam bridge of the CRTS-II ballastless track high-speed railway was adopted as the research object. A power spectral density curve spectrum of seismic-induced track geometric irregularity based on guarantee rate was established, and the influence of structural damping ratio on the power spectral density curve under different earthquake intensities was analysed. A simplified calculation method for power spectral density curve of seismic-induced track geometric irregularity was proposed. The main findings of this work are as follows: (1) Seismic-induced track irregularities of high-speed railway bridges are dominated by alignment irregularity, and a segmented polynomial function can be fitted to the power spectral density curve of the seismic-induced track irregularity based on guarantee rate; (2) Seismic-induced track irregularities of high-speed railway bridges worsen as structural damping decreases and peak ground acceleration increases; (3) More spikes are observed in the high-frequency waveband of the power spectral density curve, and seismic-induced track irregularity results in more high frequency periodic components.

Analysis and Prediction of Poyang Lake’s Navigable Conditions under a New Hydrological Regime

Human activities have profoundly changed the hydrological regime and trends of rivers and lakes, which, in turn, has affected the utilization of their navigable conditions. However, few studies have focused on the effects of changes in hydrological regimes and trends of rivers and lakes on navigable conditions. Thus, this study intensively analyzes and investigates the navigable depth at the major control sections in the lake area during the dry season in the period before 2002, when the Three Gorges Reservoir was not yet constructed, and the period from 2003 to 2019, when the Three Gorges Project was put into operation with impoundment based on the dry-season water level curve in the Poyang Lake area since the operation of the Three Gorges Reservoir. This study also further analyzes the influence of the change in the hydrological regime on the navigable depth in the lake area. The results show that the waterway depth and width could meet the navigation requirements before 2002. From 2003 to 2019, whereas the water level with a 98% guarantee rate of duration at the Xingzi Hydrometric Station decreased, that at the Hukou Hydrometric Station increased. The waterway depth and width at both the Hukou and Xingzi hydrometric stations could meet the requirements of the size of Grade II waterways. This study also performs a simulation prediction of the water regime of Poyang Lake under a new hydrological regime using the mathematical model of water and sediment of the Changjiang River Scientific Research Institute. The results reveal that in 2030 and 2050, after the Three Gorges Reservoir has been in operation for 30–50 years, the water levels at the Hukou, Xingzi, and Wucheng hydrometric stations (Hukou) of Poyang Lake will decline by approximately 0.18–0.66 and 0.10–0.24 m, respectively. Although the overall navigable depth can basically meet the navigation requirements for a period of time, the trend of the long-term declining water level may cause unsafe navigation risks.

Pollution prevention strategies of SMEs in a green supply chain finance under external government intervention.

Small- and medium-sized enterprises (SMEs) are an important force in the promotion of economic development. However, SMEs in the supply chain are often severely punished by the government for polluting the environment through their production processes. Therefore, it is crucial to solve the environmental pollution problem of SMEs. To compensate for the "common knowledge" assumption of participants in traditional game theory, this study constructs an evolutionary game model of a green supply chain composed of SMEs, core enterprises, and commercial banks. The strategic decisions of the supply chain members are analyzed in relation to external interventions of the government. Subsequently, the impact of government incentives and penalties on these strategic choices is considered. The results show that government incentives can promote SMEs' choice to use pollution control strategies, and government penalties can reduce the risk of an SME defaulting, thus promoting the healthy development of a green supply chain finance system. Furthermore, increasing the new income of SMEs, raising the guarantee rate of core enterprises, and reducing the cost of green loans reviewed by banks and the guarantee cost of core enterprises can effectively promote the equilibrium of the tripartite evolutionary game. These findings indicate that the game model introduced here can effectively solve the environmental pollution problems of SMEs and promote the healthy development of a green supply chain finance system.

노인 빈곤 대응 정책의 우선순위 탐색에 관한 연구

The purpose of this study is to establish a strategy to explore the priorities of elderly poverty policies by analyzing the core of the system related to elderly poverty and to derive the priorities of policies with strategic implementation ability. In other words, in order to combat poverty for the elderly, the cause of poverty was identified, and a solution was suggested by finding the priority of policies through the social security system (the 2nd basic social security plan task). As a result of the study, first, it was found that it was urgent to prepare a management plan for health hazards for the elderly. To solve this problem, it is necessary to minimize temporary or post-response methods and first establish a professional management system that finds and actively responds to health risk factors. Second, it is necessary to cultivate manpower and strengthen quality to provide social services. Third, system improvement should be prepared for this, such as increasing the income guarantee rate of the unemployment benefit system and eliminating blind spots of benefits. In addition, it is necessary to strengthen policies by applying policy priority search strategies at the same time as establishing institutional solutions for elderly poverty. First, application to resource concentration, second, emphasis on education and issue symbolism, and third, use of mass media.

Random vibration analysis of the maglev vehicle-guideway system using a probability density evolution method with uncertain parameters

Random dynamic analyses of maglev vehicle-guideway coupled systems are of significant interest but have yet been comprehensively performed. This paper presents a time-dependent coupled random model of a maglev vehicle-controller-guideway-pier to investigate random vibration characteristics of the dynamic system. In the study, a 12-degree-of-freedom vehicle model is considered, a three-dimensional detailed guideway model is established using the finite element method, and the electromagnetic levitation force is controlled with a current feedback controller. Then, the generalized F-discrepancy representative point set selection strategy and probability density evolution method, which can consider multiple random parameters, are combined to analyze the dynamic system. Random vehicle parameters and irregularity are introduced and the mean value, standard deviation, limits satisfying different probability guarantee rates, and probabilistic information are calculated. The model was validated with field measurement data from an electromagnetic suspension (EMS) maglev line. In addition, the Monte Carlo method was used to assess the accuracy and efficiency of the proposed method. The results demonstrate that the proposed method has good accuracy and efficiency. The effects of vehicle running speed, random irregularity, and random vehicle loads on the dynamic vibration of the system are discussed.

Research on the Impact of Water Conservancy Projects on Downstream Floodplain Wetlands—Taking Yimin River as an Example

Continued construction of reservoirs around the world promotes socio-economic development and severely affects the ecological and hydrological processes of rivers and floodplain wetlands. In this study, the Yimin River in Inner Mongolia, China, was taken as the research area. The water inundation guarantee rate (WIGR) was used as the model basis to characterize the inundation probability of the floodplain area. The comparative study of the remote sensing data of the 38 periods before the construction of the reservoir, and the 14 periods after the construction of the reservoir, shows that: due to the impact of the reservoir construction, the submerged area of the water body (WIGR greater than zero) decreased from 49.03 km2 to 39.32 km2, a total reduction of 9.71 km2; the very low water inundation guarantee rate area (WIGR value of 0–20%) was the most affected, with a decrease of 12.14 km2, while the area of other areas with a WIGR value greater than 20% increased by 3.43 km2. In addition, the affected floodplain wetlands have significant spatial distribution characteristics: first, they are mainly distributed in the high-curvature river reach areas, and in this study 77.96% of the three high-curvature river reach areas accounted for 26.04% of the area, with area loss in very low WIGR areas; the second is that it is distributed far from the outside of the river channel, while the WIGR value in some areas near the river channel is increased. This study provides a technical reference for downstream wetland protection based on the WIGR model.

Investigating the impact of typical bridge transverse dislocations on the running performance of high-speed trains

Bridge dislocations are hard to be voided in the operation of high-speed trains, which will lead to abnormal vibration of trains. In this study, the train–track–bridge interaction theory was adopted to develop and validate a three-dimensional coupled train–track–bridge vibration model using the finite element method. Thereafter, the influence of the dislocation amplitude on the dynamic performance of high-speed trains under five typical bridge additional transverse dislocation modes was investigated utilizing the overrun probability analysis approach. The results showed that the dislocation amplitude significantly affects the transverse dynamic behavior of high-speed trains, but it has a considerably smaller impact in the vertical direction when exposed to five typical bridge transverse dislocation modes. Moreover, under constant dislocation amplitude, the transverse parallel misalignment of the girders has the greatest influence on the running performance of high-speed trains. Although all the running performance indicators did not exceed the limit in the transverse unilateral cornering condition of the girder, speed control was suggested to guarantee operational stability. At various vehicle speeds, dislocation thresholds for the transverse symmetrical cornering, transverse parallel cornering, transverse misalignment, and transverse parallel misalignment were provided based on probabilistic guarantee rates utilizing the transverse Sperling index as the control index.