scholarly journals Meandering Process and Migration Architecture: Based on the Nowitna River

2017 ◽  
Vol 6 (2) ◽  
pp. 76 ◽  
Author(s):  
Le Chen ◽  
Zhipeng Lin ◽  
Taiju Yin ◽  
Jingfu Shan ◽  
Qianjun Sun ◽  
...  
Keyword(s):  
Deflection Angle ◽  
Google Earth ◽  
Channel Structure ◽  
Quantitative Characterization ◽  
Meandering River ◽  
Meandering Channel ◽  
Original Definition ◽  
The Difference ◽  
And Migration

The meandering process has always been the topic through years and still remains a lot of unsolved mysteries. One of the most important focus is the migration architectures and models that the meandering channels follow. This article chooses the Nowitna River as the study object of the typical meandering river with high migratory processes. Though the high-resolution historical satellite images by the techniques of Google Earth and ACME Mapper, 50 meanders in the river is studied and 6 of which are chosen for meticulous characterization. During the process, the planform structure of meandering channel is re-examined and 29 kinds of architecture elements are systematically established. More importantly, in order to make a fine quantitative characterization of the channel structure of meandering river, 5 kinds of characterization parameters are proposed, extraordinarily, the parameters of the difference of along-current deflection angle, a difference of counter-current deflection angle, and expansion coefficient, these three are firstly brought forward and applied introduction. In addition, the conception of sinuosity index and curvature are also different from the original definition. Though these architectures elements the meandering process and migration structure of the Nowitna River is demonstrated. 6 kinds of planform migration structures is revealed with the quantitative characterization of characterization parameters and 9 species of meandering channel migration patterns are concluded and discussed.

scholarly journals Channel Migration of the Meandering River Fan: A Case Study of the Okavango Delta

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3319
Author(s):  
Xue Yan ◽  
Jinliang Zhang ◽  
Yang Li ◽  
Long Sun
Keyword(s):  
Sedimentary Facies ◽  
Google Earth ◽  
Okavango Delta ◽  
River Channels ◽  
Fluvial System ◽  
Channel Migration ◽  
Sinuosity Index ◽  
Meandering River ◽  
The Difference ◽  
River Migration

Okavango delta is a typical distributive fluvial system, which is composed of a series of sand island-river-swamp networks. River migration in the Okavango delta is analyzed by using satellite images from Google Earth and Alaska Satellite Facility (ASF). Four configuration characterization parameters are selected to depict and measure the meandering river. These four parameters are sinuosity index (S), curvature (C), the difference of along-current deflection angle (Δθ) and expansion coefficient (Km). In the fan, the channel migration is mainly asymmetric. According to geomorphic elements and associated features, Okavango Delta can be subdivided into three zones: axial zone, median zone and distal zone. Under the influence of slope, climate and vegetation, different migration modes are developed in different zones. As the river moves downstream, the sinuosity index of the river on the Okavango Delta decreases downstream. Based on the characteristics of different zones, the sedimentary facies model of a single source distributive fluvial system of a meandering river is proposed. The models of channel migration and sedimentary facies have wide application. This research will not only provide a basis for the prediction of future river channels but will also provide important theoretical guidance for the study of the sedimentary morphology of underground reservoirs.

scholarly journals The constants to measure the differences between Birkhoff and isosceles orthogonalities

Filomat ◽  
2016 ◽  
Vol 30 (10) ◽  
pp. 2761-2770 ◽  
Author(s):  
Hiroyasu Mizuguchi
Keyword(s):  
Normed Space ◽  
Inner Product ◽  
Product Spaces ◽  
Normed Spaces ◽  
Isosceles Orthogonality ◽  
Quantitative Characterization ◽  
Inner Product Spaces ◽  
The Difference ◽  
Geometric Constant

The notion of orthogonality for vectors in inner product spaces is simple, interesting and fruitful. When moving to normed spaces, we have many possibilities to extend this notion. We consider Birkhoff orthogonality and isosceles orthogonality, which are the most used notions of orthogonality. In 2006, Ji and Wu introduced a geometric constant D(X) to give a quantitative characterization of the difference between these two orthogonality types. However, this constant was considered only in the unit sphere SX of the normed space X. In this paper, we introduce a new geometric constant IB(X) to measure the difference between Birkhoff and isosceles orthogonalities in the entire normed space X. To consider the difference between these orthogonalities, we also treat constant BI(X).

Analisis Karakterisasi Teknologi Direct Sequence Spread Spectrum Dan Frequency Hopping Spread Spectrum

2019 ◽  
Vol 2 (2) ◽  
pp. 129-138
Author(s):  
Fawzan Galib Abdul Karim Bawahab ◽  
Elvan Yuniarti ◽  
Edi Kurniawan
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Multiple Access ◽  
Frequency Hopping ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Frequency Hopping Spread Spectrum ◽  
Two Systems ◽  
The Difference

Abstrak. Pada penelitian ini, telah dilakukan analisa karakterisasi pada teknologi Direct Sequence Spread Spectrum dan Frequency Hopping Spread Spectrum, sebagai salah satu teknik multiple-access pada sistem komunikasi. Karakterisasi dilakukan untuk mencari bagaimana cara meningkatkan keoptimalan kedua sistem tersebut, dalam mengatasi masalah interferensi dengan sistem dan channel yang sama. Dan juga untuk menentukan veriabel apa yang mempengaruhi keoptimalan kedua sistem tersebut. Karakterisasi dilakukan dengan menentukan variabel-variabel yang mempengaruhi keoptimalan keduanya. Hasil dari karakterisasi, diketahui variabel-variabel yang mempengaruhi kemampuan sistem DSSS yaitu nilai frekuensi spreading (). Sedangkan untuk sistem FHSS yaitu nilai frekuensi spreading ( dan ) dan selisih antara frekuensi hopping data dengan frekuensi hopping interferensi . Kata Kunci: BER, DSSS, FHSS, Interference, Spread spectrum. Abstract. In this study, characterization of Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum technologies have been done, as one of the multiple-access techniques in communication systems. Characterization is done to find out how to improve the ability of the two systems, in solving interference problems with the same system and channel. And also to determine what veriabel affects the ability of the two systems. Characterization is done by determining the variables that affect the ability of both. The results of the characterization, known variables that affect the ability of the DSSS system are the spreading frequency value (). As for the FHSS system, the spreading frequency value ( and ) and the difference between frequency hopping data with frequency hopping interference .

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