scholarly journals Hydrodynamic Measurements of Propagating Waves at Different Nearshore Depths in Hujeong Beach, Korea

2020 ◽  
Vol 8 (9) ◽  
pp. 690
Author(s):  
Jong Dae Do ◽  
Yeon S. Chang ◽  
Jae-Youll Jin ◽  
Weon Mu Jeong ◽  
Byunggil Lee ◽  
...  
Keyword(s):  
Satellite Images ◽  
Data Sets ◽  
Hydrodynamic Conditions ◽  
Future Studies ◽  
Shoreline Evolution ◽  
Propagating Waves ◽  
Storm Duration ◽  
Wave Nonlinearity ◽  
Wave Properties ◽  
Water Depths

This paper reports the results of hydrodynamic measurements at two different water depths to observe wave properties in the course of wave propagation, especially during storm periods, in Hujeong Beach, Korea. In addition to hydrodynamic measurements, video monitoring data and satellite images from Sentinel-II were employed to compare the temporal changes in shoreline positions and shallow water bathymetry during the storms. Through combination of a variety of observational data sets, the accuracy of analysis could be enhanced by preventing possible misinterpretation. Two significant storms were observed from two experiments conducted at different times and locations of the beach. The hydrodynamic conditions were similar in both of the periods in terms of wave and current conditions as well as wave nonlinearity such as skewness. However, the response of shoreline during the two storms was the opposite because it was eroded during the first storm but advanced during the second storm. This suggests that other controlling factors such as storm duration need to be investigated to support the analysis of cross-shore sediment transport and consequent shoreline evolution for future studies.

scholarly journals Influence of the weights in IHS and Brovey methods for pan-sharpening WorldView-3 satellite images

2017 ◽  
Vol 6 (3) ◽  
pp. 71 ◽  
Author(s):  
Claudio Parente ◽  
Massimiliano Pepe
Keyword(s):  
Satellite Images ◽  
Urban Landscape ◽  
Spectral Response ◽  
Rural Landscape ◽  
Spectral Radiance ◽  
Data Sets ◽  
Data Set ◽  
Inertial Moment ◽  
The Impact

The purpose of this paper is to investigate the impact of weights in pan-sharpening methods applied to satellite images. Indeed, different data sets of weights have been considered and compared in the IHS and Brovey methods. The first dataset contains the same weight for each band while the second takes in account the weighs obtained by spectral radiance response; these two data sets are most common in pan-sharpening application. The third data set is resulting by a new method. It consists to compute the inertial moment of first order of each band taking in account the spectral response. For testing the impact of the weights of the different data sets, WorlView-3 satellite images have been considered. In particular, two different scenes (the first in urban landscape, the latter in rural landscape) have been investigated. The quality of pan-sharpened images has been analysed by three different quality indexes: Root mean square error (RMSE), Relative average spectral error (RASE) and Erreur Relative Global Adimensionnelle de Synthèse (ERGAS).

scholarly journals Using an Online Sample to Estimate the Size of an Offline Population

Demography ◽  
2019 ◽  
Vol 56 (6) ◽  
pp. 2377-2392 ◽  
Author(s):  
Dennis M. Feehan ◽  
Curtiss Cobb
Keyword(s):  
Social Sciences ◽  
Digital Divide ◽  
Large Scale ◽  
Empirical Test ◽  
Information Age ◽  
Modern World ◽  
Randomized Experiment ◽  
Data Sets ◽  
Online Data ◽  
Future Studies

AbstractOnline data sources offer tremendous promise to demography and other social sciences, but researchers worry that the group of people who are represented in online data sets can be different from the general population. We show that by sampling and anonymously interviewing people who are online, researchers can learn about both people who are online and people who are offline. Our approach is based on the insight that people everywhere are connected through in-person social networks, such as kin, friendship, and contact networks. We illustrate how this insight can be used to derive an estimator for tracking the digital divide in access to the Internet, an increasingly important dimension of population inequality in the modern world. We conducted a large-scale empirical test of our approach, using an online sample to estimate Internet adoption in five countries (n ≈ 15,000). Our test embedded a randomized experiment whose results can help design future studies. Our approach could be adapted to many other settings, offering one way to overcome some of the major challenges facing demographers in the information age.

scholarly journals Annual and Seasonal Shoreline Evolution of Tainan Gold Coast Using Multiband Satellite Images

2018 ◽  
Vol 10 (1) ◽  
pp. 52-56
Author(s):  
Hsien-Kuo Chang ◽  
◽  
Wei-Wei Chen ◽  
Feng-Chun Tsai ◽  
Jing-Chen Liou ◽  
...  
Keyword(s):  
Satellite Images ◽  
Gold Coast ◽  
Shoreline Evolution

scholarly journals An Analysis of the Street Tree Population of Greater Melbourne at the Beginning of the 21st Century

2006 ◽  
Vol 32 (4) ◽  
pp. 155-163
Author(s):  
Stephen Frank ◽  
Glenn Waters ◽  
Russell Beer ◽  
Peter May
Keyword(s):  
Data Sets ◽  
Botanical Composition ◽  
Future Studies ◽  
Prunus Cerasifera ◽  
Tree Population ◽  
Tree Inventory ◽  
Street Tree ◽  
The Family ◽  
Family Level ◽  
Prunus Spp

An audit of the street tree population of Melbourne, Victoria, Australia, was undertaken to establish its size and botanical composition as a reference point for future studies. The 31 independent municipalities that comprise metropolitan Melbourne were approached to provide information on their respective street tree populations. Where available, data from individual municipalities on population, area, and total street length were also collected. Of the 31 municipalities surveyed, 23 had undertaken some form of street tree inventory or audit. These individual data sets were combined into a single database. Data queries were then undertaken to obtain a range of information. A total of 922,353 trees, comprising 1127 taxa, were captured in this superset of data. Australian native plants made up the majority of the trees with 60% of the total. Of the Australian native taxa, wattles (Acacia spp.), gums or eucalypts (Eucalyptus spp.), paperbarks (Melaleuca spp.), bottlebrush (Callistemon spp.), and Queensland brush box (Lophostemon confertus [R. Br.] Peter G. Wilson and Waterhouse) comprised 394,730 individuals (43% of all trees). Of the exotic taxa, Prunus spp. were the most common with 86,227 individuals (9% of the total). Queensland brush box was the most common taxon surveyed with 61,959 individuals. Purple-leaf cherry plum (Prunus cerasifera Ehrh. ‘Nigra’) was the most common exotic taxon with 35,402 individuals. An analysis of the diversity of this population showed that it meets a set of minimum diversity criteria apart from the dominance of the Myrtaceae at the family level.

scholarly journals Shoreline Extraction from WorldView2 Satellite Data in the Presence of Foam Pixels Using Multispectral Classification Method

2020 ◽  
Vol 12 (16) ◽  
pp. 2664 ◽  
Author(s):  
Audrey Minghelli ◽  
Jérôme Spagnoli ◽  
Manchun Lei ◽  
Malik Chami ◽  
Sabine Charmasson
Keyword(s):  
Spatial Resolution ◽  
Satellite Images ◽  
High Spatial Resolution ◽  
False Negative ◽  
Tohoku Earthquake ◽  
Validation Dataset ◽  
Support Vector ◽  
Spectral Angle Mapper ◽  
Shoreline Evolution ◽  
Before And After

Foam is often present in satellite images of coastal areas and can lead to serious errors in the detection of shorelines especially when processing high spatial resolution images (<20 m). This study focuses on shoreline extraction and shoreline evolution using high spatial resolution satellite images in the presence of foam. A multispectral supervised classification technique is selected, namely the Support Vector Machine (SVM) and applied with three classes which are land, foam and water. The merging of water and foam classes followed by a segmentation procedure enables the separation of land and ocean pixels. The performance of the method is evaluated using a validation dataset acquired on two study areas (south and north of the bay of Sendaï—Japan). On each site, WorldView-2 multispectral images (eight bands, 2 m resolution) were acquired before and after the Fukushima tsunami generated by the Tohoku earthquake in 2011. The consideration of the foam class enables the false negative error to be reduced by a factor of three. The SVM method is also compared with four other classification methods, namely Euclidian Distance, Spectral Angle Mapper, Maximum Likelihood, and Neuronal Network. The SVM method appears to be the most efficient to determine the erosion and the accretion resulting from the tsunami, which are societal issues for littoral management purposes.

scholarly journals Comparison of 3D Coral Photogrammetry and Coral Video Transect for Coral Lifeform Analysis Using Low-cost Underwater Action Camera

2020 ◽  
Vol 37 (1) ◽  
Author(s):  
Zuhairi Bin Ahmad ◽  
Muhammad Idzham Helmi Bin Mohd Jinah ◽  
Shahbudin Bin Saad
Keyword(s):  
Statistical Analysis ◽  
Survey Methods ◽  
Low Cost ◽  
Scientific Research ◽  
Data Sets ◽  
Percentage Cover ◽  
Future Studies ◽  
Scuba Divers ◽  
Coral Morphology ◽  
Video Transect

This research analysed the use of 3D Coral Photogrammetry (CP) and Coral Video Transect (CVT) images collected from SCUBA divers using a low-cost underwater action camera to examine the coral lifeform. A comparison was made between data sets obtained using both methods on nine transects with different coral lifeform compositions and percentage cover within an area of 4 × 7 m. The comparison of the statistical analysis for CPCe revealed that there were no significant differences (p < 0.05) between CP and CVT photos where dead corals (p = 0.006), sand (p = 0.011), and unknown (p = 0.002) are present. Additionally, the coral value (p = 0.131) between CP and CVT was not significant. CP was capable of producing prominent branching, massive, and plate coral morphology results. This suggests that survey methods using low-cost action cameras for 3D Coral Photogrammetry would yield appropriate results in terms of coral lifeform detection. Hypothetically, by improving camera quality, it will yield a higher accuracy of 3D coral images that are suitable for use in scientific research and management. Other benefits of using CP include the possibilities for future studies with 3D coral surveys using remotely operated vehicles, less field time, and 3D coral seabed information.

Combined neutron powder and X-ray single-crystal diffraction refinement of the atomic structure and hydrogen bonding of goslarite (ZnSO4·7H2O)

2005 ◽  
Vol 69 (3) ◽  
pp. 259-271 ◽  
Author(s):  
J. L. Anderson ◽  
R. C. Peterson ◽  
I. P. Swainson
Keyword(s):  
Hydrogen Bonding ◽  
Single Crystal ◽  
Atomic Structure ◽  
Data Sets ◽  
Crystal Data ◽  
Single Crystal Diffraction ◽  
Future Studies ◽  
X Ray ◽  
Hydration And Dehydration ◽  
Phase Relationships

AbstractThe atomic structure of synthetic, deuterated goslarite (ZnSO4·7D2O), a = 11.8176(6) Å, b = 12.0755(7) Å, c = 6.8270(4)Å, space group P212121, Z = 4, has been refined in a combined neutron powder diffraction and X-ray single-crystal data refinement to wRp 1.92%, Rp 1.45% and R(F2) 12.66% for the neutron powder data contribution and R(F2) 8.72% for the X-ray single-crystal data contribution. Both data sets were necessary to achieve the best overall fit agreement in the Rietveld refinement and reasonable geometry within structural units. The results of this study confirm that the H-bonding scheme for goslarite is the same as that of the other epsomite group minerals. Small but significant variations of the Zn–O bond lengths can be attributed to details of the H bonds to the O atoms of the Zn octahedra. This investigation of the atomic structure and hydrogen bonding of goslarite is groundwork for future studies into phase relationships and the mechanisms of hydration and dehydration in the ZnSO4–H2O system.

Coral bleaching and elevated sea-water temperature in Milne Bay Province, Papua New Guinea, 1996

1997 ◽  
Vol 48 (6) ◽  
pp. 513 ◽  
Author(s):  
Jocelyn M. Davies ◽  
Richard P. Dunne ◽  
Barbara E. Brown
Keyword(s):  
Papua New Guinea ◽  
Coral Bleaching ◽  
Sea Water ◽  
New Guinea ◽  
Data Sets ◽  
Positive Trend ◽  
Annual Maximum ◽  
Sea Temperature ◽  
Water Depths

A coral bleaching event began in February 1996 on reefs in Milne Bay Province, Papua New Guinea. Corals were affected on the shallow fringing reef and to water depths of greater than 20 m on the reef slope. Bleaching was extensive and in the survey area 54% of all corals were bleached. Branching corals (particularly Acropora and Pocillopora) were more severely affected than massive species. Bleaching occurred at the time of the annual maximum monthly sea temperature when long-term sea temperature data sets recorded an anomaly of + 1.29°C. Analysis of the anomalies over the previous 40 years shows a positive trend of 0.09°C per decade.

Using a transect-focused approach to interpret satellite images and analyze shoreline evolution in Haiyang Beach, China

2021 ◽  
pp. 106526
Author(s):  
Xiaodong Zhang ◽  
Xiawei Tan ◽  
Rijun Hu ◽  
Longhai Zhu ◽  
Chuang Wu ◽  
...  
Keyword(s):  
Satellite Images ◽  
Shoreline Evolution
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