Modeling of Covid-19 trade measures on essential products: a multiproduct,multicountry spatial price equilibrium framework

In this paper, we develop a unified variational inequality framework in the context of spatial price network equilibrium problems that handles multiple products with multiple demand and supply markets in multiple countries as well as multiple transportation routes. The model incorporates a plethora of distinct trade measures, which is particularly important in the pandemic, as PPEs and other essential products are in high demand, but short in supply globally. In the model, product flows as well as prices at the supply markets and the demand markets in different countries are variables that allows us to seamlessly introduce various trade measures, including tariffs, quotas, as well as price floors and ceilings. Qualitative properties are analyzed. Numerical examples are provided to illustrate the impacts of the trade measures on equilibrium product path and link flows, and on prices, and demand and supply quantities. Given the relevance of the trade measures in the world today and discussions concerning the impacts, the framework constructed in this paper is especially timely.     

Assessing the impact of urban land development on net primary productivity in the southeastern United States

The southeastern United States (SE-US) has undergone one of the highest rates of landscape changes in the country due to changing demographics and land use practices over the last few decades. Increasing evidence indicates that these changes have impacted mesoscale weather patterns, biodiversity and water resources. Since the Southeast has one of the highest rates of land productivity in the nation, it is important to monitor the effects of such changes regularly. Here, we propose a remote sensing based methodology to estimate regional impacts of urban land development on ecosystem structure and function. As an indicator of ecosystem functioning, we chose net primary productivity (NPP), which is now routinely estimated from the MODerate resolution Imaging Spectroradiometer (MODIS) data. We used the MODIS data, a 1992 Landsat-based land cover map and nighttime data derived from the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) for the years 1992/1993 and 2000 to estimate the extent of urban development and its impact on NPP. The analysis based on the nighttime data indicated that in 1992/1993, urban areas amounted to 4.5% of the total land surface of the region. In the year 2000, the nighttime data showed an increase in urban development for the southeastern United States of 1.9%. Estimates derived from the MODIS data indicated that land cover changes due to urban development that took place during the 1992-2000 period reduced annual NPP of the southeastern United States by 0.4%. Despite the uncertainties in sensor fusion and the coarse resolution of the data used in this study, results show that the combination of MODIS products such as NPP with nighttime data could provide rapid assessment of urban land cover changes and their impacts on regional ecosystem resources.     

Anticipating trade-offs between urban patterns and ecosystem service production: Scenario analyses of sprawl alternatives for a rapidly urbanizing region

Expanding demand for low-density development has restructured the urban-rural frontier throughout North America, shifting the burden of ecosystem provisioning to increasingly fragmented green infrastructure remnants. Planners have responded with approaches to control low-density development (‘sprawl’) that dominates North American exurbia. However, the ability of sprawl alternatives to preserve ecosystem services have not been systematically evaluated. Using a novel integration of land change simulation and ecosystem services modeling, we used proxies to estimate changes in water quality, climate regulation and biodiversity, and returns to landowners associated with sprawl alternatives and business-as-usual trends for the rapidly urbanizing Charlotte (NC) region by 2030. We found no single growth scenario simultaneously reduced pollution, stored additional carbon, and retained sensitive habitat, underscoring trade-offs likely encountered when balancing development and environmental outcomes. Watersheds at the extremes of the urban-rural gradient exhibited significantly different and often opposing responses to policies aimed at reducing environmental impacts. Scenarios of increased land use density yielded stronger financial returns to landowners as concentrated economic activity drove up land rents while minimizing broader pollution costs. Our simulated landscape approach overcame limitations associated with scale and data, and projected regional environmental outcomes emerging from local development events.     

The impact of urbanization and climate change on ecosystem services: A case study of the city belt along the Yellow River in Ningxia,China

Understanding the impacts of climate and land use changes driven by urbanization upon ecosystem services (ESs) has great importance in ES management and policy making. However, knowledge of their impacts on ESs correlation and bundles are still lacking. This study quantified five ESs in a spatially explicit manner for 1989–2017 in the City Belt along the Yellow River in Ningxia, China. Ten scenarios based on two Representative Concentration Pathway (RCP 2.6 and 8.5) and five urban expansion policies, were used to predict the potential change of ESs in 2017–2045. Temporal trade-off and synergy relations among ESs were analyzed using correlation analysis, while ES bundles were delineated and mapped through a self-organizing map. Results indicated that climate change has larger impacts on sand fixation and carbon sequestration, especially in mountain areas. In 2017–2045, RCP 8.5 would result in a larger increase in sand fixation (by 1.75 times to 2045) and a slight decrease in carbon sequestration (by 1.62%) than RCP 2.6. Land use change has a more substantial impact on the other three ESs than climate change, especially in the central plain. Specifically, cropland reclamation during 1989–2017 and urban expansion in 2017–2045 caused the most intense alterations in ESs. Reclamation can increase food production and nutrient retention, but reduce recreational opportunity, while urban expansion has the opposite impacts. Encouraging compact urban growth, creating riparian vegetation buffers and environment protection policies can effectively reduce the trade-offs and simultaneous losses among ESs. Specific recommendations are proposed for different sub-regions indicated by the ES bundle classification. Our results can provide references for urban planning to enhance ESs under future global warming.     

Error Sources and Post Processing Method for Land Use/cover Change Estimation of Dongguan Citybased on Landsat Remote Sensing Imagery with SVM

Urbanization is the world developing trend in the past century,which significantly changed the land use/cover of the urbanized area,and caused a series negative impacts,such as water shortage,flood increase,environment pollution,ecosystem degradation.How to estimate the land use/cover change more accurately has the prerequisite of studying the urbanization processes and its impacts,and is the research hot and challenge of the remote sensing and application communities.Dongguan city expressed the rapidest urbanization in China since China’s reform and opening door,and transferred from an agriculture county to a modern international metropolitan in less than 30 years,which has made a miracle in the world urbanization process.To prepare a high accuracy land use/cover change dataset for studying Dongguan’s urbanization process and its impacts,this paper first estimated the land use/cover change dataset by employing Support Vector Machine auto\|classification algorithm based on 12 Landsat remote sensing imageries from 1987 to 2015 at an average interval of 3 year.Then the error sources is analyzed by comparing the results estimated by using auto\|classification algorithm and visual interpretation,and a post data processing algorithm is proposed for refining the auto\|classification results.The final dataset of land use/cover change of Dongguan City is produced with the above method with an average accuracy of 86.87% and a Kappa coefficient of 0.83,which implies this product has a very good accuracy for analyzing the urbanization process of Dongguan city and its impacts.     

Supply chain network design under oligopolistic price and service level competition with foresight

In this paper a new bi-level model for designing the network structure of a competitive supply chain (SC) is presented with anticipating variable prices and service levels competition in markets under stochastic price and service level dependent elastic demands with the presence of existing, external rivals. The network structure of the new entrant SC would be designed under the limited production capacity of its producers in a way to maximize its future capturable profit in the competitive markets. The network of the new SC is assumed to be set “once and for all” but further price and service level adjustments are possible. Outer part of this bi-level model deals with strategic decisions of SC network design. Given the SC network structure assigned by the outer model in each iteration, the inner equilibrium model determines the equilibrium retail prices and service levels. Finally, we illustrate the model through several numerical examples.     

Land‐cover change and environmental impact analysis in the Greater Mankato area of Minnesota using remote sensing and GIS modelling

Land use and land‐cover (LULC) data provide essential information for environmental management and planning. This research evaluates the land‐cover change dynamics and their effects for the Greater Mankato Area of Minnesota using image classification and Geographic Information Systems (GIS) modelling in high‐resolution aerial photography and QuickBird imagery. Results show that from 1971 to 2003, urban impervious surfaces increased from 18.3% to 32.6%, while cropland and grassland decreased from 54.2% to 39.1%. The dramatic urbanization caused evident environmental impacts in terms of runoff and water quality, whereas the annual air pollution removal rate and carbon storage/sequestration remained consistent since urban forests were steady over the 32‐year span. The results also indicate that highly accurate land‐cover features can be extracted effectively from high‐resolution imagery by incorporating both spectral and spatial information, applying an image‐fusion technique, and utilizing the hierarchical machine‐learning Feature Analyst classifier. This research fills the high‐resolution LULC data gap for the Greater Mankato Area. The findings of the study also provide valuable inputs for local decision‐makers and urban planners.     

土壤碳素固定及其稳定性对土壤生产力和气候变化的影响研究

土壤碳库是陆地生态系统中最大的碳库,在全球碳循环中起着非常重要的作用。本文论述了土壤有机碳对土壤生产力和气候变化的影响。阐述了影响土壤碳含量的各种自然因素和人为因素。对土壤碳素固定以及影响土壤碳素平衡的物理、化学及生物稳定性的各种机理进行了详细评述,阐明了土壤有机碳调控的方法和途径。为控制和调节土壤有机碳储量提供了理论依据。这对今后提高土壤生产力、利用土壤的固碳潜力来降低大气中二氧化碳的浓度和缓解气候变化有着非常重要的意义。     

基于多Agent的碳排放权交易机制建模与仿真

以供应链的视角建立不同的碳排放权交易机制模型,研究不同机制的指标对企业运营决策的影响。采用Repast实验仿真平台进行建模,模型中考虑了供应链上原材料供应商、制造商、零售商和消费者等主体,分别研究了不同主体行为下制造商利润和产品价格变化情况。仿真结果表明了碳排放有偿分配机制以及公开拍卖机制对碳排放价格和企业决策的有效影响,初步验证了模型的有效性。     

Modeling different urban change trajectories and their trade-offs with food production in Jiangsu Province,China

Urban areas in China have expanded rapidly in recent decades, which mainly resulted in the conversion of fertile cropland. As the growth of urban areas is likely to continue in the next decades, there is a need for detailed assessments of urbanization impacts on food production. However, most land use models cannot simulate different types of urban change trajectories, such as expansion and densification, which constrains their capacity to inform such assessments with sufficient detail on the patterns of urbanization. In this paper, we present a land use model that represents multiple types of settlements, which allows to simulate multiple different urban change trajectories. We applied this model to Jiangsu Province, China, and assess the impact of projected urban development between 2015 and 2030 on cropland area and crop production. Results show that population growth is accommodated by different urban change trajectories, depending on the absence or presence of land use policies to maintain food security. In the absence of policies, population growth mainly leads to urban expansion, yielding losses in both cropland area and crop production. Implementing strict cropland protection policies leads to more urban densification and all population can be accommodated without a net loss of cropland. Yet, crop production decreases in this scenario as the most productive croplands are still converted and compensated by less productive areas. Protecting crop production instead leads to a small loss in cropland area combined with cropland intensification and different types of urban change, but maintains the total crop production. These results show the relevance of more nuanced representation of urban development in land use models in order to inform land use policies.     

The consequences of urban land transformation on net primary productivity in the United States

We use data from two satellites and a terrestrial carbon model to quantify the impact of urbanization on the carbon cycle and food production in the US as a result of reduced net primary productivity (NPP). Our results show that urbanization is taking place on the most fertile lands and hence has a disproportionately large overall negative impact on NPP. Urban land transformation in the US has reduced the amount of carbon fixed through photosynthesis by 0.04 pg per year or 1.6% of the pre-urban input. The reduction is enough to offset the 1.8% gain made by the conversion of land to agricultural use, even though urbanization covers an area less than 3% of the land surface in the US and agricultural lands approach 29% of the total land area. At local and regional scales, urbanization increases NPP in resource-limited regions and through localized warming “urban heat” contributes to the extension of the growing season in cold regions. In terms of biologically available energy, the loss of NPP due to urbanization of agricultural lands alone is equivalent to the caloric requirement of 16.5 million people, or about 6% of the US population.     

Detecting war‐induced abandoned agricultural land in northeast Bosnia using multispectral,multitemporal Landsat TM imagery

The use of satellite technology by military planners has a relatively long history as a tool of warfare, but little research has used satellite technology to study the effects of war. This research addresses this gap by applying satellite remote sensing imagery to study the effects of war on land‐use/land‐cover change in northeast Bosnia. Although the most severe war impacts are visible at local scales (e.g. destroyed buildings), this study focuses on impacts to agricultural land. Four change detection methods were evaluated for their effectiveness in detecting abandoned agricultural land using Landsat Thematic Mapper (TM) data from before, during and after the 1992–95 war. Ground reference data were collected in May 2006 at survey sites selected using a stratified random sampling approach based on the derived map of abandoned agricultural land. Fine‐resolution Quickbird imagery was also used to verify the accuracy of the classification. Results from these analyses show that a supervised classification of the Landsat TM data identified abandoned agricultural land with an overall accuracy of 82.5%. The careful use of freely available Quickbird imagery, both as training data for the supervised classifier and as supplementary ground reference data, suggests that these methods are applicable to other civil wars too dangerous for researchers' fieldwork.     

考虑公平关切和制造商竞争的平台型供应链定价、低碳水平和服务水平决策

随着网络购物的普及和消费者低碳偏好的增强,同时考虑到公平关切对制造商竞争最优决策的影响,构建一种由普通制造商、低碳制造商及电商平台组成的平台型供应链决策模型,分析普通制造商在不具有公平关切、具有有利不公平厌恶和不利不公平厌恶情形下的均衡决策,并在不利不公平厌恶下提出服务成本共担契约来改进供应链.研究发现:1)低碳制造商...     

Relationship between consumer’s preference and service attributes in mobile telecommunication service

The mobile telecommunication sector is increasing, thus becoming a key area for economic development in global and local markets. One of potential ways to promote competition among service providers is to introduce a mobile number portability (MNP) service. Consumer preferences are estimated using conjoint analysis. Results indicate that subscribers do not consider the MNP service an import attribute, while price and service quality are the most valuable attributes. The results of this study provide important information to implement the first service launch in mobile telecommunication and other similar information and communication technology (ICT) services.     

Towards the development of a regional version of MOD17 for the determination of gross and net primary productivity of oil palm trees

Conducting quantitative studies on the carbon balance or productivity of oil palm is important for understanding the role of this ecosystem in global climate change. The MOD17 algorithm is used for processing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to generate the values of gross primary productivity (GPP) and net primary productivity for input to global carbon cycle modelling. In view of the increasing importance of data on carbon sequestration at regional and national levels, we have studied one important factor affecting the accuracy of the implementation of MOD17 at the sub-global level, namely the database of MODIS land cover (MOD12Q1) used by MOD17. By using a study area of approximately 7 km × 7 km (49 MODIS pixels) in semi-rural Johor in Peninsular Malaysia and using Google Earth 0.75 m resolution images as ground data, we found that the land-cover type for only 16 of these 49 MODIS pixels was correctly identified by MOD12Q1 using its 1 km resolution land-cover database. This leads to errors of 24% to 50% in the maximum light use efficiency, leading to corresponding errors of 24% to 50% in the GPP. We show that by using the Finer Resolution Observation and Monitoring – Global Land Cover (FROM-GLC) land-cover database developed by Gong et al., this particular error can be essentially eliminated, but at the cost of using extra computing resources.     

成像光谱技术在土地利用动态遥感监测中的应用研究

随着数字化调查技术的发展，国土资源管理对土地利用动态遥感监测提出了更高的要求，目前主要采用的多光谱数据由于受光谱分辨率限制以及“同谱异物，同物异谱”现象的影响，难以满足管理需要。成像光谱数据具有较高光谱分辨率。在类别细分方面具有一定的优势，在当前土地利用动态遥感监测中具有一定的应用潜质。该文针对成像光谱数据特点，探索了与成像光谱数据相适应的土地利用动态遥感监测方法，提出了异常光谱检测法，该方法在试验区应用中取得了良好效果。     

Nash equilibrium solution in a vendor–buyer supply chain model with permissible delay in payments

In practice, vendors (or sellers) often offer their buyers a fixed credit period to settle the account. The benefits of trade credit are not only to attract new buyers but also to avoid lasting price competition. On the other hand, the policy of granting a permissible delay adds not only an additional cost but also an additional dimension of default risk to vendors. In this paper, we will incorporate the fact that granting a permissible delay has a positive impact on demand but negative impacts on both costs and default risks to establish vendor–buyer supply chain models. Then we will derive the necessary and sufficient conditions to obtain the optimal solution for both the vendor and the buyer under non-cooperative Nash equilibrium. Finally, we will use two numerical examples to show that (1) granting a permissible delay may significantly improve profits for both the vendor and the buyer, and (2) the sensitivity analysis on the optimal solution with respect to each parameter.     

Price suppression stimulation in a local market

In the paper, we study possible organization of a free multi-agent multi-commodity local market that stimulates price suppression. Market participants (agents) produce different commodities and services sold both in the local and external markets. Agents are interdependent: produce of one agents is a product of industrial consumption of other agents. Agents independently make decisions about shares of a product sent to external and internal markets and about prices that they fix in the local market. Prices of sale and purchase in the external market are fixed and do not depend on actions of the agents of the local market. Commodities of industrial consumption required for the agents cam be bought both in the local or external markets. We study a mechanism of price suppression based on the priority of access to resources granted to more compliant agents. It is shown that at sufficiently soft conditions of “valid competition,” all agents of the local market can obtain an increase in profitability concerning the strategy of purchase and sale in the external market only. Small and low-profitable enterprises obtain the highest relative gains in profitability.     

基于ARIMA和BP神经网络的生态系统服务价值预测仿真

针对现有生态系统服务价值预测体系误差大、研究不足等问题,本文构建了面向未来生态服务价值的预测机制。该机制采用主成分分析法和Person相关系数法,建立了以GDP、人口、土地利用率、土地管理政策和城市人口密度为驱动力的生态系统服务价值关联矩阵,提出了基于ARIMA和BP神经网络的生态系统服务价值的时间序列预测机制。为验证预测机制有效性,本文选取中国主要土地利用类型代表省份的真实土地数据集进行分析,研究结果表明本文建立的预测模型平均绝对误差仅为0.023,且从预测结果来看,未来草地生态会向较好趋势发展,林地生态发展不容乐观。