scholarly journals Refining Urban Built-Up Area via Multi-Source Data Fusion for the Analysis of Dongting Lake Eco-Economic Zone Spatiotemporal Expansion

2020 ◽  
Vol 12 (11) ◽  
pp. 1797 ◽  
Author(s):  
Qianming Li ◽  
Bohong Zheng ◽  
Bing Tu ◽  
Yusheng Yang ◽  
Zhiyuan Wang ◽  
...  
Keyword(s):  
Extraction Methods ◽  
Dongting Lake ◽  
Urban Agglomeration ◽  
Rapid Urbanization ◽  
Distance Method ◽  
Nighttime Light ◽  
Economic Zone ◽  
Objective Basis ◽  
Pattern Index

Rapid urbanization has given rise to serious urban problems. It is crucial to understand the urbanization process to accurately and quickly identify boundary changes in urban built-up areas and implement planning schemes and adjustments in scientific and effective ways. This study proposes a new method to automate and refine the extraction of urban built-up areas by using Landsat and nighttime light (NTL) imagery. The urban agglomeration of Dongting Lake Ecological Economic Zone (UADLEEZ) Landsat data are mapped to NTL data using resampling, superpixel segmentation, and assigning the blank part with the Euclidean distance method. We then compared our findings with those produced via traditional threshold extraction methods. In total, 33 built-up areas of UADLEEZ boundary maps were produced between 1992 and 2018. Thus, we reached the following conclusions: (1) the urban built-up areas obtained via our proposed method are finer than those obtained via other threshold extraction methods; (2) we applied the extraction method to UADLEEZ, and analyzed the expansion of the urban agglomeration based on expansion scale, gravity center offset, and landscape pattern index, the analysis of expansion process is consistent with the actual situation; (3) the proposed method can be used to draw long-term dynamic maps of urban extents in units of years, and the results can be used to update the existing products. This study can serve as a reference for future urban planning, and provide both adjustment programs for relevant departments, and an objective basis for governmental decision-making.

scholarly journals The Construction and Optimization of Ecological Security Pattern in the Harbin-Changchun Urban Agglomeration, China

2019 ◽  
Vol 16 (7) ◽  
pp. 1190 ◽  
Author(s):  
Rong Guo ◽  
Tong Wu ◽  
Mengran Liu ◽  
Mengshi Huang ◽  
Luigi Stendardo ◽  
...  
Keyword(s):  
Urban Agglomeration ◽  
Ecosystem Functions ◽  
Ecological Security ◽  
Least Cost Path ◽  
Rapid Urbanization ◽  
Songhua River ◽  
Urban Agglomerations ◽  
Ecological Corridors ◽  
Ecological Protection ◽  
Security Pattern

Urban agglomerations have become a new geographical unit in China, breaking the administrative fortresses between cities, which means that the population and economic activities between cities will become more intensive in the future. Constructing and optimizing the ecological security pattern of urban agglomerations is important for promoting harmonious social-economic development and ecological protection. Using the Harbin-Changchun urban agglomeration as a case study, we have identified ecological sources based on the evaluation of ecosystem functions. Based on the resistance surface modified by nighttime light (NTL) data, the potential ecological corridors were identified using the least-cost path method, and key ecological corridors were extracted using the gravity model. By combining 15 ecological sources, 119 corridors, 3 buffer zones, and 77 ecological nodes, the ecological security pattern (ESP) was constructed. The main land-use types composed of ecological sources and corridors are forest land, cultivated land, grassland, and water areas. Some ecological sources are occupied by construction, while unused land has the potential for ecological development. The ecological corridors in the central region are distributed circularly and extend to southeast side in the form of tree branches with the Songhua River as the central axis. Finally, this study proposes an optimizing pattern with "four belts, four zones, one axis, nine corridors, ten clusters and multi-centers" to provide decision makers with spatial strategies with respect to the conflicts between urban development and ecological protection during rapid urbanization.

scholarly journals Inferring Long-Term Demand of Newly Established Stations for Expansion Areas in Bike Sharing System

2021 ◽  
Vol 11 (15) ◽  
pp. 6748
Author(s):  
Hsun-Ping Hsieh ◽  
Fandel Lin ◽  
Jiawei Jiang ◽  
Tzu-Ying Kuo ◽  
Yu-En Chang
Keyword(s):  
New York ◽  
Feature Extraction ◽  
Real World ◽  
Extraction Methods ◽  
Real World Data ◽  
Urban Dynamics ◽  
Bike Sharing ◽  
The Government ◽  
Short Time

Research on flourishing public bike-sharing systems has been widely discussed in recent years. In these studies, many existing works focus on accurately predicting individual stations in a short time. This work, therefore, aims to predict long-term bike rental/drop-off demands at given bike station locations in the expansion areas. The real-world bike stations are mainly built-in batches for expansion areas. To address the problem, we propose LDA (Long-Term Demand Advisor), a framework to estimate the long-term characteristics of newly established stations. In LDA, several engineering strategies are proposed to extract discriminative and representative features for long-term demands. Moreover, for original and newly established stations, we propose several feature extraction methods and an algorithm to model the correlations between urban dynamics and long-term demands. Our work is the first to address the long-term demand of new stations, providing the government with a tool to pre-evaluate the bike flow of new stations before deployment; this can avoid wasting resources such as personnel expense or budget. We evaluate real-world data from New York City’s bike-sharing system, and show that our LDA framework outperforms baseline approaches.

scholarly journals Multiperiod Hierarchical Location Problem of Transit Hub in Urban Agglomeration Area

2017 ◽  
Vol 2017 ◽  
pp. 1-15
Author(s):  
Ting-ting Li ◽  
Rui Song ◽  
Shi-wei He ◽  
Ming-kai Bi ◽  
Wei-chuan Yin ◽  
...  
Keyword(s):  
Travel Time ◽  
Urban Population ◽  
Location Problem ◽  
Clonal Selection ◽  
Urban Agglomeration ◽  
Population Migration ◽  
Clonal Selection Algorithm ◽  
Rapid Urbanization ◽  
Transportation Demand ◽  
Hierarchical Location

With the rapid urbanization in developing countries, urban agglomeration area (UAA) forms. Also, transportation demand in UAA grows rapidly and presents hierarchical feature. Therefore, it is imperative to develop models for transit hubs to guide the development of UAA and better meet the time-varying and hierarchical transportation demand. In this paper, the multiperiod hierarchical location problem of transit hub in urban agglomeration area (THUAA) is studied. A hierarchical service network of THUAA with a multiflow, nested, and noncoherent structure is described. Then a multiperiod hierarchical mathematical programming model is proposed, aiming at minimizing the total demand weighted travel time. Moreover, an improved adaptive clonal selection algorithm is presented to solve the model. Both the model and algorithm are verified by the application to a real-life problem of Beijing-Tianjin-Hebei Region in China. The results of different scenarios in the case show that urban population migration has a great impact on the THUAA location scheme. Sustained and appropriate urban population migration helps to reduce travel time for urban residents.

scholarly journals Long-term psychological outcomes of flood survivors of hard-hit areas of the 1998 Dongting Lake flood in China: Prevalence and risk factors

PLoS ONE ◽  
2017 ◽  
Vol 12 (2) ◽  
pp. e0171557 ◽  
Author(s):  
Wenjie Dai ◽  
Atipatsa C. Kaminga ◽  
Hongzhuan Tan ◽  
Jieru Wang ◽  
Zhiwei Lai ◽  
...  
Keyword(s):  
Risk Factors ◽  
Dongting Lake ◽  
Psychological Outcomes

scholarly journals Incubation methods for assessing mineralizable nitrogen in soils under sugarcane

2013 ◽  
Vol 37 (2) ◽  
pp. 450-461 ◽  
Author(s):  
Eduardo Mariano ◽  
Paulo Cesar Ocheuze Trivelin ◽  
José Marcos Leite ◽  
Michele Xavier Vieira Megda ◽  
Rafael Otto ◽  
...  
Keyword(s):  
N Mineralization ◽  
Standard Technique ◽  
Extraction Methods ◽  
N Fertilization ◽  
Chemical Extraction ◽  
Net N Mineralization ◽  
Anaerobic Incubation ◽  
Aerobic Incubation ◽  
Mineralizable N

Considering nitrogen mineralization (N) of soil organic matter is a key aspect for the efficient management of N fertilizers in agricultural systems. Long-term aerobic incubation is the standard technique for calibrating the chemical extraction methods used to estimate the potentially mineralizable N in soil. However, the technique is laborious, expensive and time-consuming. In this context, the aims of this study were to determine the amount of soil mineralizable N in the 0-60 cm layer and to evaluate the use of short-term anaerobic incubation instead of long-term aerobic incubation for the estimation of net N mineralization rates in soils under sugarcane. Five soils from areas without previous N fertilization were used in the layers 0-20, 20-40 and 40-60 cm. Soil samples were aerobically incubated at 35 ºC for 32 weeks or anaerobically incubated (waterlogged) at 40 ºC for seven days to determine the net soil N mineralization. The sand, silt and clay contents were highly correlated with the indexes used for predicting mineralizable N. The 0-40 cm layer was the best sampling depth for the estimation of soil mineralizable N, while in the 40-60 cm layer net N mineralization was low in both incubation procedures. Anaerobic incubation provided reliable estimates of mineralizable N in the soil that correlated well with the indexes obtained using aerobic incubation. The inclusion of the pre-existing NH4+-N content improved the reliability of the estimate of mineralizable N obtained using anaerobic incubation.

scholarly journals Satellite Imaging and Long-Term Mosquito Surveillance Implicate the Influence of Rapid Urbanization on Culex Vector Populations

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 269
Author(s):  
Eleanor N. Field ◽  
Ryan E. Tokarz ◽  
Ryan C. Smith
Keyword(s):  
Land Use ◽  
Disease Transmission ◽  
Culex Pipiens ◽  
Management Practices ◽  
Mosquito Species ◽  
Land Use Changes ◽  
Mosquito Vector ◽  
Rapid Urbanization ◽  
Mosquito Surveillance

The ecology and environmental conditions of a habitat have profound influences on mosquito population abundance. As a result, mosquito species vary in their associations with particular habitat types, yet long-term studies showing how mosquito populations shift in a changing ecological landscape are lacking. To better understand how land use changes influence mosquito populations, we examined mosquito surveillance data over a thirty-four-year period for two contrasting sites in central Iowa. One site displayed increasing levels of urbanization over time and a dramatic decline in Culex pipiens group (an informal grouping of Culex restuans, Culex pipiens, and Culex salinarius, referred to as CPG), the primary vectors of West Nile virus in central Iowa. Similar effects were also shown for other mosquito vector populations, yet the abundance of Aedes vexans remained constant during the study period. This is in contrast to a second site, which reflected an established urban landscape. At this location, there were no significant changes in land use and CPG populations remained constant. Climate data (temperature, total precipitation) were compiled for each location to see if these changes could account for altered population dynamics, but neither significantly influence CPG abundance at the respective site locations. Taken together, our data suggest that increased landscape development can have negative impacts on Culex vector populations, and we argue that long-term surveillance paired with satellite imagery analysis are useful methods for measuring the impacts of rapid human development on mosquito vector communities. As a result, we believe that land use changes can have important implications for mosquito management practices, population modeling, and disease transmission dynamics.

Phycocyanin: A Natural Antioxidant to Combat Free Radicals

2021 ◽  
Vol 18 ◽  
Author(s):  
Dingling Zhuang ◽  
Doris Ying Ying Tang ◽  
Kit Wayne Chew ◽  
Tau Chuan Ling
Keyword(s):  
Free Radicals ◽  
Industry 4.0 ◽  
Extraction Process ◽  
Extraction Methods ◽  
Natural Antioxidant ◽  
High Demand ◽  
Advanced Technologies ◽  
Ultrasonic Assisted ◽  
Clinical Trial Results

: Various research showed that antioxidants can effectively overcome the damage caused by free radicals to the human health. Therefore, antioxidants are identified as one of the main directions in the development of health care and cosmetics products due to high demand in the market. This review mainly focuses on the phycocyanin, a type of natural antioxidant mainly found in cyanobacteria. This mini review summarizes the phycocyanin sources and numerous extraction methods of phycocyanin along with the analytical methods in determining its ability to suppress free radicals. Phycocyanin has been proven to play an important role in scavenging free radicals and enhancing the body’s antioxidant capacity. However, there are lack of long-term randomized clinical trial results that can be used as evidence in showing the benefits of phycocyanin. The existing phycocyanin extraction methods using solvents, ultrasonic-assisted, freeze-thaw and etc. can extract high-quality phycocyanin efficiently and quickly. Scientists are also trying to incorporate advanced technologies such as "Industry 4.0" to optimize and enhance the industrial production of phycocyanin. Lastly, this review also describes the difficulties faced during the phycocyanin production or extraction process and financial obstacles in order to achieve the popularization of phycocyanin.

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