scholarly journals Understanding Urban Expansion on the Tibetan Plateau over the Past Half Century Based on Remote Sensing: The Case of Xining City, China

2020 ◽  
Vol 13 (1) ◽  
pp. 46
Author(s):  
Xinhao Pan ◽  
Yihang Wang ◽  
Zhifeng Liu ◽  
Chunyang He ◽  
Haimeng Liu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Urban Sprawl ◽  
Satellite Data ◽  
Urban Expansion ◽  
Urban Land ◽  
The Tibetan Plateau ◽  
The Past ◽  
Past Half Century ◽  
Past Half

The Tibetan Plateau (TP) is an important area that affects global sustainable development. Quantifying spatiotemporal patterns of urbanization is crucial for maintaining the sustainability on the TP. This study took Xining City, the largest city on the TP, as an example to understand the urban expansion in this region in the past 50 years. We combined the high-resolution spy satellite data and China’s long-term urban land dataset (CULD) to quantify the urban expansion of Xining City. The object-oriented random forest classification was performed to extract urban land from spy satellite data in 1969, and the inter-annual correction was used to combine urban land information from 1969 to 2017. We found that the proposed approach can accurately quantify the urban expansion of Xining City over the past half century with an overall accuracy of 91% and a kappa coefficient of 0.86. Such high accuracy benefits from the fine resolution of spy satellite data and the consistency of CULD. We also found that Xining City experienced accelerated and fragmented urban sprawl to higher altitude areas, as a result of socioeconomic development and topographical limitations. The acceleration of urban expansion was more obvious, and the urban landscape fragmentation was more serious at high altitude areas. Such urban expansion encroached on cropland and grassland, and caused increased risks of landslides and other geological disasters. Therefore, Xining City urgently needs to promote the development of compact cities to control urban sprawl at higher altitude areas and provide a reference for improving urban sustainability across the TP. In this study, we analyzed the urban expansion of Xining city from 1969 to 2017, and provided a reliable way to understand the long-term spatiotemporal urbanization based on remote sensing, which has the potential for wide applications. In addition, the extracted urban information can help to improve the urban sustainability of Xining City and the entire TP.

scholarly journals Understanding Urban Growth in Beijing-Tianjin-Hebei Region over the Past 100 Years Using Old Maps and Landsat Data

2021 ◽  
Vol 13 (16) ◽  
pp. 3264 ◽  
Author(s):  
Shuang Li ◽  
Zhongqiu Sun ◽  
Yafei Wang ◽  
Yuxia Wang
Keyword(s):  
Remote Sensing ◽  
Urban Area ◽  
Spatial Data ◽  
Urban Expansion ◽  
Remote Sensing Images ◽  
The Past ◽  
Old Maps ◽  
The World ◽  
The City

Studying urban expansion from a longer-term perspective is of great significance to obtain an in-depth understanding of the process of urbanization. Remote sensing data are mostly selected to investigate the long-term expansion of cities. In this study, we selected the world-class urban agglomeration of Beijing-Tianjin-Hebei (BTH) as the study area, and then discussed how to make full use of multi-source, multi-category, and multi-temporal spatial data (old maps and remote sensing images) to study long-term urbanization. Through this study, we addressed three questions: (1) How much has the urban area in BTH expanded in the past 100 years? (2) How did the urban area expand in the past century? (3) What factors or important historical events have changed the development of cities with different functions? By comprehensively using urban spatial data, such as old maps and remote sensing images, geo-referencing them, and extracting built-up area information, a long-term series of urban built-up areas in the BTH region can be obtained. Results show the following: (1) There was clear evidence of dramatic urban expansion in this area, and the total built-up area had increased by 55.585 times, from 126.181 km2 to 7013.832 km2. (2) Continuous outward expansion has always been the main trend, while the compactness of the built-up land within the city is constantly decreasing and the complexity of the city boundary is increasing. (3) Cities in BTH were mostly formed through the construction of city walls during the Ming and Qing dynasties, and the expansion process was mostly highly related to important political events, traffic development, and other factors. In summary, the BTH area, similarly to China and most regions of the world, has experienced rapid urbanization and the history of such ancient cities should be further preserved with the combined use of old maps.

scholarly journals Bioplastics – An Eco-friendly Alternative to Petrochemical Plastics

2019 ◽  
Vol 14 (1) ◽  
pp. 49-59 ◽  
Author(s):  
M. Selvamurugan Muthusamy ◽  
Sivakumar Pramasivam
Keyword(s):  
Public Awareness ◽  
Plastic Pollution ◽  
Daily Lives ◽  
Global Estimate ◽  
The Past ◽  
Past Half Century ◽  
Term Change ◽  
Past Half ◽  
Emission Of Greenhouse Gases

Plastics have varied application and have become an essential part of our daily lives. The use of the plastics has increased twenty-fold in the past half-century and is expected to double again in the next 20 years. As a global estimate, around 330 million tonnes of the plastics are produced per annum. The production, use and disposal of the plastics emerged as a persistent and potential environmental nuisance. The improper disposal of the plastics ends up in our environment, resulting in the deaths of millions of animals annually and also the reduction in fertility status of the soil. The bioplastics products are manufactured to be biodegradable with similar functionality to that of conventional plastics, which has the potential to reduce the dependence on petrochemicals based plastics and related environmental problems. The expansion and development of the bioplastics and their products would lead to the increase in the sustainability of environment and reduction in the emission of greenhouse gases. The bioplastics innovation would be a key to the long-term solution for the plastic pollution. However, a widespread public awareness is also essential in effecting longer-term change against plastic pollution.

scholarly journals Mapping the Rapid Decline of the Intertidal Wetlands of China Over the Past Half Century Based on Remote Sensing

2020 ◽  
Vol 8 ◽  
Author(s):  
Song Song ◽  
Zhifeng Wu ◽  
Yuefeng Wang ◽  
Zheng Cao ◽  
Zhenyu He ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Rapid Decline ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
Intertidal Wetlands ◽  
Past Half

Afghanistan-US Relations

2019 ◽  
Author(s):  
Paul D. Miller
Keyword(s):  
Strategic Partnership ◽  
Terrorist Attacks ◽  
Short Term ◽  
Global Response ◽  
The Past ◽  
Thrust Front ◽  
Past Half Century ◽  
Partnership Agreement ◽  
Past Half

Afghanistan has twice been thrust front and center of US national security concerns in the past half-century: first, during the Soviet-Afghan War, when Afghanistan served as a proxy for American efforts to combat Soviet influence; and second, as the frontline state and host for America’s global response to al-Qaida’s terrorist attacks of 2001. In both instances, American involvement swung from intensive investment and engagement to withdrawal and neglect. In both cases, American involvement reflected US concerns more than Afghan realities. And both episodes resulted in short-term successes for American security with long-term consequences for Afghanistan and its people. The signing of a strategic partnership agreement between the two countries in 2012 and a bilateral security agreement in 2013 created the possibility of a steadier and more forward-looking relationship—albeit one that the American and Afghan people may be less inclined to pursue as America’s longest war continues to grind on.

Bacterial responses to environmental change on the Tibetan Plateau over the past half century

2015 ◽  
Vol 18 (6) ◽  
pp. 1930-1941 ◽  
Author(s):  
Yongqin Liu ◽  
John C. Priscu ◽  
Tandong Yao ◽  
Trista J. Vick-Majors ◽  
Baiqing Xu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Environmental Change ◽  
The Tibetan Plateau ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
Past Half

The empirical trend

2013 ◽  
Vol 18 (2) ◽  
pp. 281-289 ◽  
Author(s):  
Geoffrey Sampson
Keyword(s):  
Sampling Technique ◽  
Literature Survey ◽  
Turn Of The Century ◽  
Systematic Sampling ◽  
The Past ◽  
Past Half Century ◽  
Term Change ◽  
Scientific Standards ◽  
Past Half

Linguistic science of the past half-century has often been distorted through neglect of normal scientific standards of empirical falsifiability. An earlier paper in this journal used a quantitative literature survey to examine how far in practice the newer trend towards use by linguists of corpora and other empirical data sources had progressed. The result was ambiguous: a trend towards greater empiricism had occurred since about 1970, but around the turn of the century it appeared to have reversed, and the end of the period surveyed (2002) fell so soon thereafter that it was hard to guess whether this reversal was a blip or a long-term change. With a further decade of linguistic literature to examine, the present paper repeats the survey using a more systematic sampling technique, and this yields results that are much more clearcut than those of the earlier paper.

EDITORIAL: Migration and competitiveness: Japan and the United States

2013 ◽  
Vol 10 (2) ◽  
pp. 115-124
Author(s):  
Philip L. Martin
Keyword(s):  
United States ◽  
The United States ◽  
Variable Cost ◽  
Fixed Cost ◽  
Special Issue ◽  
Science And Engineering ◽  
The Past ◽  
Past Half Century ◽  
Key Sectors ◽  
Past Half

Japan and the United States, the world’s largest economies for most of the past half century, have very different immigration policies. Japan is the G7 economy most closed to immigrants, while the United States is the large economy most open to immigrants. Both Japan and the United States are debating how immigrants are and can con-tribute to the competitiveness of their economies in the 21st centuries. The papers in this special issue review the employment of and impacts of immigrants in some of the key sectors of the Japanese and US economies, including agriculture, health care, science and engineering, and construction and manufacturing. For example, in Japanese agriculture migrant trainees are a fixed cost to farmers during the three years they are in Japan, while US farmers who hire mostly unauthorized migrants hire and lay off workers as needed, making labour a variable cost.

Reframing the Sciences of the Long Eighteenth Century

2020 ◽  
Vol 50 (1-2) ◽  
pp. 58-66
Author(s):  
Giuliano Pancaldi
Keyword(s):  
Eighteenth Century ◽  
History Of Science ◽  
Science Policy ◽  
Special Issue ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
History Of ◽  
Long Eighteenth Century ◽  
Past Half

Here I survey a sample of the essays and reviews on the sciences of the long eighteenth century published in this journal since it was founded in 1969. The connecting thread is some historiographic reflections on the role that disciplines—in both the sciences we study and the fields we practice—have played in the development of the history of science over the past half century. I argue that, as far as disciplines are concerned, we now find ourselves a bit closer to a situation described in our studies of the long eighteenth century than we were fifty years ago. This should both favor our understanding of that period and, hopefully, make the historical studies that explore it more relevant to present-day developments and science policy. This essay is part of a special issue entitled “Looking Backward, Looking Forward: HSNS at 50,” edited by Erika Lorraine Milam.

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