Abandonment Rate Research Articles

Human-pet Relationship, Pet Abandonment, and Clinical Correlation for Patients Infected with Dermatophytosis of the Glabrous Skin

Objective: The study on human-pet relationship and pet abandonment among dermatophytosis patients is limited. This study aims to review these correlations. Materials & Methods: A two-year retrospective cross-sectional study was conducted. Case record forms were reviewed for clinical manifestations, fungal identification, human-pet relationships, and changes in the relationships after dermatophytosis diagnosis. Results: A total of 230 dermatophytosis patients from the Dermatology outpatient clinic, Siriraj Hospital, were included. The mean age was 41.9 ± 19.1 years and 51.3% were female. Among 170 cases with positive fungal culture, zoophilic dermatophytosis from M. canis infection was identified in 15.9% which was predominately found in females and manifested as shorter duration of onset, and higher involvement on exposed areas when compared to anthropophilic dermatophytosis. Most (71%%) of patients with M. canis infection classified themselves as pet-lovers. The relationship with pets had changed after the dermatophytosis diagnosis in 41% of them which was statistically different from 8.8% in non-pet lovers (P = 0.001). The overall pet abandonment rate was 26.6%. The abandonment rate was 40.9% among non-pet lovers, while 30.6% was reported among pet lovers. Conclusion: Zoophilic M. canis infection was associated with rapid onset and on predominant-exposed areas. Some pets could be asymptomatic, so identification of the reservoirs of dermatophytosis is important in the treatment process and helps prevent future recurrence. Paying attention to human-pet relationships and pet abandonment is critical. Knowledge about dermatophytosis transmission, and appropriate pet management should be advised to decrease abandonment.

Research on Optimal Ratio of Wind-PV Capacity and Energy Storage Optimization Configuration of Regional Power Grid

Reasonable optimization of the wind-photovoltaic-storage capacity ratio is the basis for efficiently utilizing new energy in the large-scale regional power grid. Firstly, a method of wind-photovoltaic capacity ratio optimization for improving new energy accommodation is proposed, including the evaluation model of new energy accommodation and the model of wind-photovoltaic capacity ratio optimization. An optimal allocation method of Energy Storage for improving new energy accommodation is proposed to reduce the power abandonment rate further. Finally, according to the above method, the optimal ratio of wind-photovoltaic capacity and the optimal allocation of energy storage in the target year of the regional power grid are studied. The results can provide a reference for the subsequent construction of wind and photovoltaic power plants and the region’s allocation of energy storage capacity.

Managing Queues with Reentrant Customers in Support of Hybrid Healthcare

The COVID-19 pandemic has profoundly boosted the use of hybrid healthcare settings, which orchestrate face-to-face services together with virtual ones. The advantages of virtual healthcare services are clear: they are less costly and less disruptive for patients who can receive the service in the comfort of their home and reduce patients’ exposure to illnesses prevalent in healthcare facilities. Nevertheless, there is evidence that patients are likely to require a supplementary in-person service upon completion of their virtual service. Motivated by such settings, we study a multiservice queueing system with face-to-face, virtual, and supplementary service channels. The service operator needs to allocate service capacity among the three classes and decide how to prioritize the patients when a service provider becomes available. The strong dependency between virtual and supplementary visits makes the problem challenging. Based on a fluid relaxation, we develop an index-based policy, the [Formula: see text] rule (or the [Formula: see text] rule in short), which, in addition to the holding cost, service time, abandonment rate, and service reward, also carefully balances the return probability and associated penalty. The theoretical results along with numerical experiments demonstrate the effectiveness of the proposed policy and the importance of capacity coordination when managing hybrid service settings. Our work provides insights on the trade-off between convenience and the value of care when offering virtual healthcare services. Funding: The author was supported in part by an Israel Science Foundation [Grant 277/21] and the Israel National Institute for Health Policy Research [Grant 2021/160/R].

The pattern of abandoned cropland and its productivity potential in China: A four-years continuous study

The increased requirement of food production with the rising population challenges limited cultivation land in China. The abandoned cropland has high potential in grain production to ensure China's food security. However, the spatial distributions of abandoned cropland in China are understudied and therefore it is difficult to estimate its potential grain production. Our study proposed a new definition of abandoned cropland considering unique multiple cropping systems in China, and estimate the abandoned cropland distribution and grain productivity potential by using Landsat-8 and GF-1 images under deep learning technology. The area of abandoned cropland in three main grain-producing regions was approximately 1.53 million hectares during 2014–2017. The estimated images agreed with the field survey and the national agricultural statistical data with the accuracy larger than 87 %. The spatial distribution of abandoned cropland in China was scattered and a high abandonment rate observed in the Middle-lower Yangtze River Plain. Moreover, the uncultivated cropland accounted for approximately 50 % of the total area of abandoned cropland. The maximum production potential of abandoned cropland could reach 8.5 million tons, including 2.7, 2.5 and 3.3 million tons of maize, wheat and rice, respectively. The exploitation of abandoned cropland is also beneficial for additional soybean production in China. National-scale estimation of abandoned cropland in China is crucial for land use policy making and cropland protection, as well the implementation of national food security strategy.

Monitoring Cropland Abandonment in Southern China from 1992 to 2020 Based on the Combination of Phenological and Time-Series Algorithm Using Landsat Imagery and Google Earth Engine

Cropland abandonment is one of the most widespread types of land-use change in Southern China. Quickly and accurately monitoring spatial-temporal patterns of cropland abandonment is crucial for food security and a good ecological balance. There are still enormous challenges in the long-term monitoring of abandoned cropland in cloud and rain-prone and cropland-fragmented regions. In this study, we developed an approach to automatically obtain Landsat imagery for two key phenological periods, rather than as a time series, and mapped annual land cover from 1989 to 2021 based on the random forest classifier. We also proposed an algorithm for pixel-based, long-term annual land cover correction based on prior knowledge and natural laws, and generated cropland abandonment maps for Guangdong Province over the past 30 years. This work was implemented in Google Earth Engine. Accuracy assessment of the annual cropland abandonment maps for every five years during study period revealed an overall accuracy of 92–95%, producer (user) accuracy of 90–96% (73–87%), and Kappa coefficients of 0.81–0.88. In recent decades, the cropland abandonment area was relatively stable, at around 50 × 104 ha, while the abandonment rate gradually increased with a decrease in the cultivated area after 2000. The Landsat-based cropland abandonment monitoring method can be implemented in regions such as southern China, and will support food security and strategies for maintaining ecological balance.

Spatial Characteristics of the Abandonment Degree of Residential Quarters Based on Data of the Housing Sales Ratio—A Case Study of Kunming, China

The abandonment degree of an urban residential building can reflect the popularity of residential areas. This study uses this idea as a basis for proposing the concept of using residential quarters’ abandonment rate to measure the abandonment degree of an area. The spatial pattern of the abandonment rate and its clustering characteristics were obtained by taking 2517 residential quarters in Kunming’s Main Urban District as research object, and using their listing for sale ratio data. Thereafter, curve estimation was used to explore the influencing factors of abandonment rate. The results are as follows. (1) The abandonment rate of the four circles in Kunming’s Main Urban District increases from inside to outside, showing the pattern of the core area–second ring area–third ring area–new urban district, with evident “core–edge” characteristics. (2) The relationship between distance from the city center, housing ages, and abandonment rate can be well fitted using a quadratic function and shows an inverted “U”-shaped “rising–declining” trend. The relationship between housing prices and abandonment rate is fitted by the inverse function, showing an evident “up” trend. This study is a reference for managers of relevant departments and urban planners in formulating reasonable urban housing development policies.

Active Power Cooperative Control for Wind Power Clusters with Multiple Temporal and Spatial Scales

To improve the control of active power in wind power clusters, an active power hierarchical predictive control method with multiple temporal and spatial scales is proposed. First, the method from the spatial scale divides the wind power clusters into the cluster control layer, sub-cluster coordination layer and single wind farm power regulation layer. Simultaneously, from the temporal scale, the predicted data are divided layer by layer: the 15 min power prediction is deployed for the first layer; the 5 min power prediction is employed for the second layer; the 1 min power prediction is adopted for the third layer. Secondly, the prediction model was developed, and each hierarchical prediction was optimized using MPC. Thirdly, wind farms are dynamically clustered, and then the output power priority of wind farms is established. In addition, the active power of each wind farm is controlled according to the error between the dispatch value and the real-time power with feedback correction so that each wind farm achieves cooperative control with optimal power output. Finally, combined with the simulation of practical wind power clusters, the results show that the wind abandonment rate was reduced by 2.13%, and the dispatch of the blindness was overcome compared with the fixed proportional strategy. Therefore, this method can improve the efficiency of cooperative power generation.

Optimal Scheduling of Multi-Source Combined System with Pumped Storage Based on Improved Black Hole Algorithm

With the high-penetration and large-scale renewable energy sources access to the grid, the supply and demand imbalance caused by their uncertainty is becoming increasingly serious, so a wind-pv-hydropower-thermal-pumped storage joint optimal dispatch model is established to alleviate this problem. The output power of each unit is optimized with the minimum cost of power generation, pollutant treatment and renewable energy abandonment as the optimization objectives. An improved black hole algorithm (IBHA) is proposed by introducing cross operation, mutation operation and inertia parameters into the black hole algorithm (BHA), which is used to obtain the optimal solution and coordinate various energy and energy storage devices. The operation results illustrate that the optimization strategy can effectively reduce the power abandonment rate, the operation cost, and the influence of seasonal variation on the system while suppressing the power fluctuation. Comparing the results of the two cases, the renewable energy abandonment rate of the system has been effectively reduced after adding pumped storage energy, which is kept below 4%, the improved algorithm improves the solution accuracy and shortens the solution time.

Research on the Electricity Market Clearing Model for Renewable Energy

The development of renewable energy in China has made remarkable achievements, but the problem of renewable energy consumption has become increasingly prominent. This paper establishes a power market trading system for renewable energy, with the aim of promoting large-scale renewable energy consumption and increasing the enthusiasm of renewable energy producers and users to participate in market transactions. First, according to the power generation cost, the backup cost of renewable energy power plants and the possible quotation strategies of other renewable energy producers, a quotation model of renewable energy producers is established. In the clearing of the spot market by renewable energy producers, the independent market operator conducts the first-stage clearing of the electricity market with the goal of maximizing social welfare. After the announcement of the clearing results, the renewable energy producers that did not win the bid will revise their quotations and carry out the second stage clearing to realize the consumption of renewable energy. In this paper, the particle swarm algorithm combined with the CPLEX solver is used to solve the problem, and finally, different scenarios are analyzed through example analysis. The results show that, compared with the conventional power market trading mechanism, the energy abandonment rate of the power market trading mechanism for renewable energy proposed in this paper drops from 8.2% to 2.1%, and the profit margin of renewable energy producers increase by 6.6%. It is demonstrated that the proposed electricity market mechanism can effectively promote the consumption of renewable energy and increase the income of renewable energy producers.

Configuration optimization of an off-grid multi-energy microgrid based on modified NSGA-II and order relation-TODIM considering uncertainties of renewable energy and load

This study develops a two-stage hybrid decision framework to configure an off-grid multi-energy microgrid (MEMG) while considering uncertainties in renewable energy resources and load demand. In the first stage, a non-dominated sorting genetic algorithm (NSGA)-II modified by reinforcement learning is employed to obtain Pareto solutions. Its three objectives are minimum total annual cost (TAC), loss of energy supply possibility (LESP), and energy abandonment rate (EAR). In the second stage, the weights for TAC, LESP, and EAR are obtained using the order relation method, and the best solution is chosen from Pareto solutions using a ranking method. Then, a case study is carried out to validate the rationality and feasibility of the proposed framework. The results show that when uncertainties and electricity storage are simultaneously considered, the respective values of TAC, LESP, and EAR are 81.148 million ¥, 16.146%, and 1.486%, respectively. A comparative analysis illustrates how the proposed method is better than NSGA-II, because the values of spacing metric and diversity are 0.0004 and 2.3546 obtained with the proposed method, and the former is smaller than 0.0013 and the latter is larger than 2.2713 obtained by employing NSGA-II. Therefore, the proposed framework is helpful to construct an off-grid renewable MEMG.

Confirmed cases of tuberculosis in Brazil between 2015 and 2019

Tuberculosis (TB) is a communicable disease considered serious. The time difference between obtaining test results from a patient and starting treatment increases the chance of transmitting tuberculosis. The purpose of this article was to verify the number of confirmed cases of tuberculosis in Brazil between 2015 and 2019 according to the notification region, age group, form of the disease and closure situation. For this, a qualitative and quantitative research was carried out. Quantitative data were taken from the IT department of the Brazilian Unified Health System (DATASUS)[7]. Regions of the country with the highest HDI seem to deal better with the transmission, treatment and cure of tuberculosis. The economically active population, with greater exposure to other people, are the most affected group due to the type of transmission. The pulmonary type of tuberculosis affects the largest number of people due to the form of airborne transmission and also the performance of the body’s immune system, with the fight being maintained at the cavity level. The high rate of success in the treatment (cure) reflects that there is a real possibility of combating the bacillus. Unfortunately, the abandonment rate demonstrates how bad a social imbalance can do to public health.

Research on Multiobjective Optimal Operation Strategy for Wind-Photovoltaic-Hydro Complementary Power System

To address the problems of wind and solar generation volatility and lose of wind and photovoltaic resources, on the basis of the complementary property of wind-solar-water, the topology structure of the wind-solar-water synergy power generation system is constructed. Taking the minimum grid fluctuation index, the minimum wind-photovoltaic-hydro discard rate and the greatest economic effectiveness of the power station as the goal functions and considering various constraints of the wind, photovoltaic, and hydrostation units, a triobjective optimization running model of the wind-photovoltaic-water synergy system is established. Meanwhile, this essay suggests an IMOSSA on the basis of tent chaotic sequence and random wandering strategy to settle the described triobjective optimization issue. Taking Hubei Pankou as an example for simulation analysis, after choosing the best scheme, IMOSSA compared with MOSSA, MOGWO, and NSGA-II, the volatility of sunny days is reduced by 12.39%, 19.5%, and 36.71%, respectively; the wind-photovoltaic abandonment rate is reduced by 11.17%, 22.5%, and 38.03%, respectively, while in the rainy days the volatility is reduced by 8.09%, 18.34%, and 47.03%, respectively; the wind-photovoltaic abandonment rate is reduced by 14.84%, 16.86%, and 40%, respectively. Therefore, it is possible to demonstrate the validity of the proposed three-objective model and the efficiency of the IMOSSA in solving the issue. The efficiency of the optimization operation approach suggested in this research is confirmed by the case study, providing a new idea for the large-scale consumption of new energy in high-proportion hydropower grids.

Reveal the severe spatial and temporal patterns of abandoned cropland in China over the past 30 years

The abandonment phenomenon is familiar in China. It threatens food security and seriously affects the sustainable development of society, the economy, and the natural environment. However, monitoring and mapping abandoned cropland on a large scale remains a challenge because of its complex land-use change process. According to the World Food and Agriculture Organization, cropland not used for agricultural production for more than 5 years is defined as abandoned cropland. This study uses the Landsat high-precision long-time series product to detect cropland nationwide from 1990 to 2019 by using the sliding window method on Google Earth Engine to profile the spatial distribution, intensity, trend, frequency, and recultivation of abandoned cropland. Between 1992 and 2015, the results illustrate that the total area of abandoned cropland in China was 559,170.26 km2, 18.59 % of the cropland area. Excluding the recultivated cropland area, China's abandoned cropland area amounted to 392,156.24 km2, 13.03 % of the total cropland. Cropland abandonment is mainly distributed in the second terrain gradient in midwestern and southwestern regions such as Inner Mongolia and Gansu. It rarely happens in western and eastern coastal areas. A high abandonment rate area usually has high elevation and slope. The light index is negatively correlated with the abandonment rate in suburban areas. This study is the first to map the spatiotemporal distribution of abandoned cropland in China with high precision at 30 m resolution. It provides an important basis for policies regarding the recultivation of abandoned cropland.

A Capacity Optimization Method for a Hybrid Energy Storage Microgrid System Based on an Augmented ε- Constraint Method

In general, microgrids have a high renewable energy abandonment rate and high grid construction and operation costs. To improve the microgrid renewable energy utilization rate, the economic advantages, and environmental safety of power grid operation, we propose a hybrid energy storage capacity optimization method for a wind–solar–diesel grid-connected microgrid system, based on an augmented ε- constraint method. First, the battery is coupled with a seasonal hydrogen energy storage system to establish a hybrid energy storage model that avoids the shortcomings of traditional microgrid systems, such as a single energy storage mode and a small capacity. Second, by considering the comprehensive cost and carbon emissions of the power grid within the planning period as the objective function, the abandonment rate of renewable energy as the evaluation index, and the electric energy storage and seasonal hydrogen energy storage system operating conditions as the main constraints, the capacity allocation model of the microgrid can be constructed. Finally, an augmented ε- constraint method is implemented to optimize the model above; the entropy–TOPSIS method is used to select the configuration scheme. By comparative analysis, the results show that the optimization method can effectively improve the local absorption rate of wind and solar radiation, and significantly reduce the carbon emissions of microgrids.

What are the reasons for abandonment of low vision devices prescribed in a large tertiary eye care centre?

To investigate abandonment rates of near-vision low vision devices (LVDs) and factors that influence abandonment among patients attending a tertiary low vision rehabilitation centre in South India. Two hundred and eighty-six adults with low vision completed the modified device abandonment survey 1 year following device prescription. The survey included six questions: possession of device, timing of last use, reasons for abandonment, tasks for which the device was used, payment type and change in quality of life (QoL) from device use. The primary outcome measure was abandonment. Multivariate logistic regression analysis was used to investigate factors for abandonment. Three hundred and twelve near-vision devices were prescribed (mean, 1.09 device per patient.) Stand magnifiers (35%) followed by hand-held magnifiers (24%) were most frequently prescribed. Mean logMAR visual acuity (Snellen) in the better-seeing eye was 0.80 (6/38). Of the prescribed near-vision devices, 22% (95% CI, 17 to 27) were abandoned. Patients who abandoned the device were significantly older than those who did not (49.3 ± 17.2 vs. 43.5 ± 18.1 years; p=0.03). In multivariable analysis, patients reporting no change in their QoL from device use had higher odds of abandoning the device (OR: 63.97; 95% CI, 23.77 to 172.12). Device-related (31%) and psychological (30%) factors were the most frequent reasons for abandonment. Among device-related issues, the most frequent reason was that patients felt the device was too complex to use (50%) followed by being too cumbersome to use (25%). The abandonment rate for near-vision LVDs in South India was comparable with that reported in high-income countries. Patients reporting no change in their QoL had a higher likelihood of abandoning the device compared with those who reported some change. Device-related and psychological factors were the most frequent reasons for abandonment. These results can be used to develop strategies to improve compliance with use of devices.

Examination of Spatial Causes of Housing Abandonment Problem in the Historic Environment

Tarihi çevrelerin korunması, mekânsal bilgiyi gelecek nesillere aktarma araçlarından birisidir. Tarihi yapıların kullanılarak yaşatılması ise kentsel koruma açısından önemli bir politika olarak karşımıza çıkmaktadır. Ancak tarihi doku ya da kentsel sit alanlarında yer alan ve zengin geçmişe sahip konutlar, yasalarla korunmalarına rağmen sahipleri tarafından terk edilmektedir. Bu çalışmanın amacı, tarihi çevrede yer alan konutların terk edilmelerinin mekânsal nedenlerini ortaya koymaktır. Çalışma alanı olarak zengin tarihi yapı stoku ve korunmakta olan kentsel dokusuyla İzmir ilinin Bayındır ilçe merkezi belirlenmiştir. Bayındır kentsel sit alanında yer alan yapıların terk edilme oranı %19’dur. Çalışmanın yöntemi üç aşamadan oluşmaktadır. İlk olarak konutların terk edilmesine neden olan mekânsal faktörler belirlenmiştir. Ardından bu mekânsal faktörlere dair veriler saha çalışması ile toplanmıştır. Son aşamada ise istatistiksel analizler ile mekânsal faktörler ile terk edilme arasındaki ilişki irdelenmiştir. Ki-kare ve t-testi sonuçlarına göre, konutun komşuluğunda terk edilmiş konutların varlığı (p<0,05), tuvaletin avluda ya da konutun içinde olması (p<0,05), avlu ya da konut girişinde erişimi zorlaştıran merdiven ya da kot farkı olup olmaması (p<0,10) ve konut içinde erişimi zorlaştıran merdiven ya da kot farkı olup olmaması (p<0,05) faktörleri ile terk edilme arasında ilişki tespit edilmiştir. Terk edilmeye neden olan mekânsal faktörlerin incelenmesi, kentsel sit alanlarındaki özellikli kent dokusunun sürdürülebilirliğinin sağlamasına yönelik politikaların geliştirilebilmesi açısından önemlidir. Bu çalışma kentsel sit alanlarında terk edilmeyi tetikleyen sosyal ve diğer mekânsal faktörlerle genişletilerek geliştirilebilecektir.

Understanding Determinants of End-User’s Continuance Intention on Fitness Wearable Technology

With more and more people adopting wearable fitness devices to help them carry out physical activities more regularly, the market analysis reports a relatively high abandonment rate after six months of usage. This article aims to contribute to consumer study in fitness wearable technology by understanding the underlying determinants of consumer’s continuance intention to use wearable fitness devices (e.g., fitness trackers), and proposing a few suggestions to fitness wearable companies and designers for further product development. This research article consists of two empirical studies. In the first study, we propose a research model that is based on the expectation-confirmation model and integrates two extra factors, which are 'technology innovativeness’ and 'eHealth literacy’. The data collection is done via online surveys. The second study is intended to design upon the findings from the first study, during which we did arrange an offline education intervention for student participants and conduct a 2 × 2 experimental study. For both studies, we use quantitative methods to analyse data and draw conclusions. From the first study, we found that users’ technology innovativeness and eHealth literacy will indirectly influence their continuous intention to use wearable fitness devices. The second study reveals that male consumers tend to increase their continuance intention to use wearable fitness devices when their eHealth literacy has been enhanced by training. To sum up, the value of this article lies in two aspects. First, it is the first study in the field of fitness wearable technology (FWT) to learn how consumer behaviour will be influenced by a person’s eHealth literacy. Second, our study goes further to investigate to what extent the improvement of eHealth literacy will influence consumer’s continuous intention.

Responses of birds to vineyard abandonment in Slovakia

Vineyards are semi-natural, human-modified ecosystems where the extent of natural elements is determined primarily by the type of management and by the abandonment rate. In this study, we analyzed bird assemblages in 40 vineyard plots in six wine-growing regions of Slovakia. We examined bird communities on managed and abandoned vineyards to identify possible patterns. Environmental and spatial predictors of species richness and abundance were analyzed using partial redundancy analysis (pRDA) and a generalized additive model (GAM). Bird communities were influenced by both environmental and spatial factors. As expected, elevation explained most of the variation in bird assemblages. Tree coverage was found to be more important than the vineyard abandonment rate in explaining the observed variability. Only a portion of the variance in the species data reported by pRDA was accounted for by the difference in vineyard abandonment degree. Our results show that the species richness of all birds was positively correlated to vegetation density (captured by NDVI). Herb and shrub cover had less effect on bird species richness than tree cover and the presence of traditional agricultural vineyard landscapes. However, shrub density emerged as a key explanatory factor for the abundance of habitat specialists. Our study shows that, depending on whether the goal is to promote the diversity and abundance of farmland or non-farmland bird species, different conservation biology approaches should be used. Increasing the landscape diversity and avoiding large vineyard abandonment are necessary if we are to stem the decline of valuable farmland species. • The area of managed vineyards in Slovakia continues to decrease. • The species richness of all birds positively correlated to NDVI. • Tree coverage was found to be one of the most important factors in explaining bird species variation. • The shrub density turned out to be a key explanatory factor of habitat specialist abundance. • Bird abundance and species richness increased continuously with the presence of the traditional agricultural landscape.

Study on Spatio-Temporal Pattern Changes and Prediction of Arable Land Abandonment in Developed Area: Take Pingyang County as an Example

The problem of arable land abandonment has become increasingly prominent in China as an important hidden danger of regional and national grain security. Therefore, it is necessary to fully understand its developmental mechanism in order to improve land protection policies and maintain the sustainable use of arable land. This study took Pingyang County in the Yangtze River Delta Economic Zone as an example. Based on remote sensing image data in 2000, 2010, and 2018, the landscape pattern index was used to reveal the changes in the landscape pattern of abandoned land in the study area, and the FLUS model was used to simulate the spatial and temporal distribution changes in abandoned land in the study area in 2028. The results showed that the abandoned areas in the study area spread rapidly from 2000 to 2018, the area of abandoned land increased nearly 12 times in the past 18 years, and the areas with a high abandonment rate were concentrated in the western and northwestern mountainous areas of the study area. In the view of the landscape pattern, the areas with a high fragmentation degree of abandoned land gradually shifted to the western mountainous areas from 2000 to 2018, and the areas with high landscape complexity of abandoned land gradually shifted from the middle to the northern and western areas. The simulation results of abandoned land showed that the high-value areas of abandoned land rate in the study area would be more concentrated by 2028. Among them, the abandoned land rate of arable land in the northwest would increase to 15.76~24.89%, while the landscape fragmentation and complexity of abandoned land would be slightly lower than that in 2018. Finally, some countermeasures were proposed for the protection and sustainable utilization of cultivated land resources.

Capacity configuration and economic evaluation of a power system integrating hydropower, solar, and wind

Determining the economic feasibility and optimal capacity scheme of a hybrid system is the premise of its development. This study proposed a framework for capacity configuration and economic evaluation of the hydro-solar/photovoltaic-wind power system. First, a hydro-solar-wind power system capacity configuration and economic evaluation mathematical model aiming at the maximum net present value was presented. Then, an economic dispatch model of cascade hydropower plants considering flood control level and water supply demand was established, and its target is to maximize the hydropower annual electricity revenues. Finally, the framework was examined by a practical project in China. The results indicated that (1) the hydro-solar-wind power system in Qinghai Province is economically feasible; (2) the hydro-solar-wind complementation leads to the increase of multi-year average water abandonment rate and transmission line utilization hours. Through the regulation of cascade reservoirs, the multi-year average water abandonment rate can be obviously reduced and the hydropower annual electricity revenues can be increased; (3) the hydro-solar-wind power system capacity configuration and economic evaluation model is most sensitive to feed-in tariff, social discount rate, and annual average utilization hours of solar/wind. Thus, this study has important guiding value for the economic development of the hydro-solar-wind power system.