scholarly journals River corridor ventilation analysis and riverfront planning strategy in Tianjin’s urban core area

2021 ◽  
Vol 237 ◽  
pp. 04022
Author(s):  
Tong Ma ◽  
Tian Chen
Keyword(s):  
Core Area ◽  
Frontal Area ◽  
Common Belief ◽  
Development Mode ◽  
Area Index ◽  
Planning Strategy ◽  
Urban Core ◽  
Planning Methods ◽  
River Corridors ◽  
River Corridor

River corridors are important potential wind path in cities. This paper took the river in the core area of Tianjin as the research object. By using two ventilation indicators as frontal area index (FAI) and frontal area density (FAD), the overall ventilation and pedestrian level ventilation of riverfront area were quantitatively analyzed. The result showed that contrary to common belief, due to the high FAI of the riverfront area, river corridor in Tianjin’s core area did not play the role of wind path but obstructed the wind flow. Also the low FAD indicator of the riverfront area lead to a better outdoor comfort in summer but worse comfort in winter. After verified the correlation between planning indicators (floor area ratio, building height and site coverage) and ventilation indicators, a cluster pattern urban riverfront development mode was proposed. Also a ventilation corridor planning methods based on the river direction and dominant wind direction was suggested. These planning strategy will be more conductive to the wind path and cooling island potential of the river corridors in urban core area.

PENGARUH KONDISI EKOSISTEM DARAT KORIDOR SUNGAI TERHADAP DANAU RAWA PENING

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
E. Hanggari Sittadewi
Keyword(s):  
Water Quality ◽  
Water Hyacinth ◽  
River Corridors ◽  
River Corridor ◽  
Environment Degradation

Environment degradation in Rawa Pening’s lake is caused of descend lake’s functions for some potentions and activities around the lake. Some problems in the Rawa Pening’s lake has emerged i.e : decrease water quality of lake, abundance of water hyacinth growth and increase sediment in the bottom lake. A research about infl uences of land ecosystem on Panjang and Galeh river corridors for Rawa Pening’s lake has been done. Two rivers named Galeh and Panjang are the largest water contribution in Rawa Pening’s lake. That caused the land characteristic ecosystem of that river corridors gives infl uences in the Rawa Pening’s lake.Key words: land ecosystem, river corridor, water contribution, Rawa Pening Lake.

scholarly journals A Feedrate Planning Method for the NURBS Curve in CNC Machining Based on the Critical Constraint Curve

2021 ◽  
Vol 11 (11) ◽  
pp. 4959
Author(s):  
Peng Guo ◽  
Yijie Wu ◽  
Guang Yang ◽  
Zhebin Shen ◽  
Haorong Zhang ◽  
...  
Keyword(s):  
Planning Method ◽  
Cnc Machining ◽  
Arc Length ◽  
Kinematic Constraint ◽  
Nurbs Curve ◽  
Planning Strategy ◽  
Feedrate Planning ◽  
Curvature Constraint ◽  
Planning Methods ◽  
The Relationship

The curvature of the NURBS curve varies along its trajectory, therefore, the commonly used feedrate-planning method, which based on the acceleration/deceleration (Acc/Dec) model, is difficult to be directly applied in CNC machining of a NURBS curve. To address this problem, a feedrate-planning method based on the critical constraint curve of the feedrate (CCC) is proposed. Firstly, the problems of existing feedrate-planning methods and their causes are analyzed. Secondly, by considering both the curvature constraint and the kinematic constraint during the Acc/Dec process, the concept of CCC which represents the relationship between the critical feedrate-constraint value and the arc length is proposed. Then the CCC of a NURBS curve is constructed, and it has a concise expression conforming to the Acc/Dec model. Finally, a feedrate-planning method of a NURBS curve based on CCC and the Acc/Dec model is established. In the simulation, a comparison between the proposed method and the conventional feedrate-planning method is performed, and the results show that, the proposed method can reduce the Acc/Dec time by over 40%, while little computational burden being added. The machining experimental results validate the real-time performance and stability of the proposed method, and also the machining quality is verified. The proposed method offers an effective feedrate-planning strategy for a NURBS curve in CNC machining.

A quantitative method to detect the ventilation paths in a mountainous urban city for urban planning: A case study in Guizhou, China

2016 ◽  
Vol 26 (3) ◽  
pp. 422-437 ◽  
Author(s):  
Shi Ling Chen ◽  
Jun Lu ◽  
Wei Wei Yu
Keyword(s):  
Land Use ◽  
Urban Land Use ◽  
Frontal Area ◽  
High Mountain ◽  
Least Cost Path ◽  
Area Index ◽  
Mapping Procedure ◽  
Urban City ◽  
Local Topography ◽  
The Government

In this paper, a new frontal area index (FAI) mapping method is presented to describe the surface roughness of Renhuai, as an example of typical medium high mountain gorge type Karst city. Comparing with the traditional calculating method of FAI, a local topography (hills) factor is added to the calculation of the FAI in each 100 m × 100 m grid cell. The results show that the modified FAI is more strongly related to the mountainous land-use type than traditional, and local topography regions with large podium structure had higher values than other urban land-use types in mountainous city. With the frontal area index mapping procedure and a self-compiled least cost path analysis method, the potential airflow corridors traversing through the study area can be located, and the total computation time is shorter and less than 1 s. Air volume, a significant measurement index of urban ventilation capacity, is then simulated in computational fluid dynamics model (CFD-PHOENICS) to confirm the significance and efficiency of these specific ventilation corridors. Based on our findings, the government and urban planners may use the descendent maps to understand the urban ventilation paths within a mountainous city for urban local renovation decisions.

A Study on the Planning Method of Underground Space in Urban Core District - Taking Hangzhou Eastern New City Zone as an Example

2011 ◽  
Vol 71-78 ◽  
pp. 1411-1420
Author(s):  
Cheng Zhang ◽  
Si Wei Wang
Keyword(s):  
Development Project ◽  
Design Concept ◽  
Planning Method ◽  
Core Area ◽  
Underground Space ◽  
Surrounding Area ◽  
The Core ◽  
Railway Construction ◽  
Urban Core ◽  
New City

Nowadays, Underground space exploitation is one of the directions of the main focus in the construction of Hangzhou. This paper comprehensively introduces the schematic design of the underground space exploitation of Hangzhou east station, combined with the underground space development project of the core area in Hangzhou eastern new city zone. Firstly, the background of the surrounding area is discussed to illuminate the important status of the core area of eastern new city zone in Hangzhou’s future construction. Then, the holistic design concept and construction goal of the underground space exploitation of the core area are presented, and its functions and layout are clarified focusing on the railway construction and circumjacent exploitation project of Hangzhou east station. Lastly, the executive plan about the underground space exploitation of the core area of Hangzhou eastern new city zone is expatiated comprehensively.

Open source riverscapes: Analyzing the river corridor of the Naryn River in Kyrgyzstan based on open access data

2021 ◽  
Author(s):  
Florian Betz ◽  
Magdalena Lauermann ◽  
Bernd Cyffka
Keyword(s):  
Remote Sensing ◽  
Open Access ◽  
Large Scale ◽  
Data Sets ◽  
Hierarchical Systems ◽  
Geomorphological Mapping ◽  
Open Access Data ◽  
Access Data ◽  
River Corridors ◽  
River Corridor

<p>In fluvial geomorphology as well as in freshwater ecology, rivers are commonly seen as nested hierarchical systems functioning over a range of spatial and temporal scales. Thus, for a comprehensive assessment, information on various scales is required. Over the past decade, remote sensing based approaches have become increasingly popular in river science to increase the spatial scale of analysis. However, data-scarce areas have been mostly ignored so far despite the fact that most remaining free flowing – and thus ecologically valuable – rivers worldwide are located in regions characterized by a lack of data sources like LiDAR or even aerial imagery. High resolution satellite data would be able to fill this data gap, but tends to be too costly for large scale applications what limits the ability for comprehensive studies on river systems in such remote areas. This in turn is a limitation for management and conservation of these rivers.</p><p>In this contribution, we suggest an approach for river corridor mapping based on open access data only in order to foster large scale geomorphological mapping of river corridors in data-scarce areas. For this aim, we combine advanced terrain analysis with multispectral remote sensing using the SRTM-1 DEM along with Landsat OLI imagery. We take the Naryn River in Kyrgyzstan as an example to demonstrate the potential of these open access data sets to derive a comprehensive set of parameters for characterizing this river corridor. The methods are adapted to the specific characteristics of medium resolution open access data sets and include an innovative, fuzzy logic based approach for riparian zone delineation, longitudinal profile smoothing based on constrained quantile regression and a delineation of the active channel width as needed for specific stream power computation. In addition, an indicator for river dynamics based on Landsat time series is developed. For each derived river corridor parameter, a rigor validation is performed. The results demonstrate, that our open access approach for geomorphological mapping of river corridors is capable to provide results sufficiently accurate to derive reach averaged information. Thus, it is well suited for large scale river characterization in data-scarce regions where otherwise the river corridors would remain largely unexplored from an up-to-date riverscape perspective. Such a characterization might be an entry point for further, more detailed research in selected study reaches and can deliver the required comprehensive background information for a range of topics in river science.</p>

Research and Application of the Power Network Planning Methods Oriented to the Clustered City Planning

2013 ◽  
Vol 448-453 ◽  
pp. 2636-2641
Author(s):  
Hai Long Bao ◽  
Chen Fang ◽  
Jian Lin Yang ◽  
Qiang Yin
Keyword(s):  
Transmission Lines ◽  
City Planning ◽  
Network Planning ◽  
Power Network ◽  
Metropolitan Regions ◽  
Planning Strategy ◽  
Planning Scheme ◽  
Planning Methods ◽  
Functional Orientation ◽  
Power Network Planning

As the urbanization of cities is rapidly developing in China, metropolitan regions establish the clustered power network planning scheme on the background of the clustered city planning of the adjacent areas. Base on the functional orientation and difference of clusters, as well as the theory of hierarchical clustered city planning, the article puts forward the power network planning thoughts and methods. As cluster becomes a planning unit, the load density method is applied in the differential load forecast and the location of substations as well as the path of transmission lines is selected with the thoughts of separation according to different layers and areas. And then, the results will be compared and verified with the planning scheme of the other clustered cities which have the similar function orientation and planning strategy. Finally, the planning methods will be standardized. The application in the power network of Cluster of Livable Education City in Zhengzhou has proved that the methods and steps of the power planning method proposed is able to meet the demand of the network development under the situation of the rapid growth of load.

scholarly journals A PAISAGEM COMO CONDICIONADORA DE BORDAS DE FRAGMENTOS FLORESTAIS

FLORESTA ◽  
2005 ◽  
Vol 35 (1) ◽  
Author(s):  
Bethania Cristiane Herrmann ◽  
Efraim Rodrigues ◽  
André De Lima
Keyword(s):  
Species Composition ◽  
Patch Size ◽  
Nearest Neighbor ◽  
Core Area ◽  
Forest Fragments ◽  
Spatial Structures ◽  
Landscape Index ◽  
Area Index ◽  
Components Analysis ◽  
The Relationship

Fragmentos florestais diferem em sua estrutura espacial afetando a composição de espécies em suas bordas. O objetivo deste trabalho foi analisar a influência dos índices da paisagem sobre as bordas de fragmentos florestais próximos à cidade de Londrina - PR. As características estruturais dos fragmentos aqui consideradas incluem área, forma, área central e índice de área central; e as características estruturais da paisagem: área da classe, tamanho médio e coeficiente de variação do tamanho dos fragmentos de floresta, distância média até o fragmento florestal mais próximo e total de bordas de floresta. A relação entre composição de espécies, fragmentos florestais e índices de paisagem foi estudada através de Análise de Correspondência Canônica. Os índices de maior importância foram: área, forma e área central dos fragmentos. Godoy, fragmento com 2371,14 ha e inclui o Parque Estadual Mata dos Godoy, apresentou maior variação na composição de espécies quando comparado com os demais. The landscape as conditioning of edges of forest fragments Abstract Forests fragments differ in their spatial structure afecting the species composition of edges. The objective of this paper was to analyze the influence of some landscape index over sapling species composition in edges of forests fragments near Londrina - PR. The spatial structures of fragments considered in this paper involved area, shape, core area and core area index; and the spatial structures of landscape: class area, mean patch size, coefficient of variation of the size of the patch (%), mean nearest neighbor distance and total edge of forest. The relationship between sapling species composition, forests fragments and landscape index were evaluated through Principal Components Analysis. Godoy, fragment with 2371,14 ha showed more variation in the species composition when compared with other fragments.

scholarly journals The Influence of Climate Change on River Corridors in Drylands: The Case of the Tehuacán-Cuicatlán Biosphere Reserve

2021 ◽  
Vol 9 ◽  
Author(s):  
Jacinto Elías Sedeño-Díaz ◽  
Eugenia López-López
Keyword(s):  
Climate Change ◽  
Biosphere Reserve ◽  
Warming Trend ◽  
Dry Season ◽  
World Heritage Site ◽  
Landsat 8 ◽  
Temperature Anomalies ◽  
Salado River ◽  
River Corridors ◽  
River Corridor

The Tehuacán-Cuicatlán Biosphere Reserve, Mexico (TCBR) is the southernmost arid or semi-arid zone with the highest biodiversity in North America and is a UNESCO World Heritage site. Two main hydrographic streams cross the TCBR, the Salado River (an endogenous river) and the Grande River (an exogenous river). This study investigated temperature anomalies over the past 40 years. We analyzed potential differences between sub-basins and riparian areas on both streams using various indices, namely the Global Warming Index (GWI), Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Normalized Difference Drought Index (NDDI), and analyzed the potential relationship of these indices with climate change. Time series of satellite-based precipitation (June 2000–December 2020) and air temperature (January 1980–December 2020) were analyzed. A set of Landsat 8 OLI TIRS imagery from the driest and wettest months (2013–2020) was used to estimate NDVI, NDWI, and NDDI. These indices were evaluated separately for the sub-basins and river corridors in the dry and rainy seasons. The precipitation records indicate that in the Grande river sub-basin, precipitation is higher than in the Salado river sub basin. Normalized temperature anomalies and the GWI suggest a warming trend from 1994 to 2020, increasing up to 0.86°C in the Salado River and 0.52°C in the Grande River. The Grande and Salado sub basins showed significant differences between dry and wet seasons for each index (NDVI, NDWI, and NDDI). A Discriminant Analysis showed that the Salado sub-basin and the Salado River corridor are associated with severe drying conditions in the dry season (highest NDDI values). In the wet season, the Grande River corridor showed intermediate values of NDVI and NDWI but low values of NDDI. The Grande River corridor in the dry season was characterized by intermediate values of NDVI, NDWI, and NDDI. These river corridors provide environmental services in a trade-off with the stream and should be considered biodiversity hotspots. Due to the accentuated warming trend and the lowest precipitation, the Salado River sub-basin showed desertification signs associated with climate change. Both the Salado and the Grande River corridors showed resilience strategies to face climatic conditions.

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