EVALUATION OF DEM DERIVED BY REPEAT-PASS X-BAND STRIPMAP MODE PAZ DATA

Abstract. This paper, presents the initial results of digital elevation model (DEM) extraction from PAZ Synthetic Aperture Radar (SAR) satellite images using repeat-pass interferometric analysis. We used a multi-temporal high-resolution strip-map mode X-band satellite image that has a single polarization. Five main classes, i.e., volcanic structures, agriculture, settlement, sand dune and plain bareland are considered depending on the structure of the region. Within the category, the coherence value and DEM value are evaluated. In the accuracy assessment analysis, a reference map produced from aerial photogrammetry is used. Additionally, global DEM TanDEM-X data is also tested in the study region. In the analysis, quality metrics, mean error (ME), root means square error (RMSE), standard deviation (STD), and the normalized median absolute deviation (NMAD) are used. The results showed that as the temporal baseline increases the coherence values and the quality of the DEM product decrease. The RMSE values range between 2.36 m to 7.09 m in different classes. The TanDEM-X data provided high accuracies over each class range from 0.88 m to 2.40 m. Since the study area is vulnerable to sinkhole formation, sinkhole-like signals were also observed in the interferograms obtained from different and sequential pairs. The high-resolution repeat-pass PAZ data pointed out its potential for interferometric products generation

MONITORING THE SLOWLY DEVELOPING LANDSLIDE WITH THE INSAR TECHNIQUE IN SAMSUN PROVINCE, NORTHERN TURKEY

Landslides are prominent natural events with high destructive power. Since they affect large areas, it is important to monitor the areas they cover and analyse their movement. Remote sensing data and image processing techniques have been used to monitor landslides in different areas. Synthetic aperture radar (SAR) data, particularly with the Interferometric SAR (InSAR) method, is used to determine the velocity vector of the surface motion. This study aims to detect the landslide movements in Samsun, located in the north of Turkey, using persistent scattering InSAR method. Archived Copernicus Sentinel-1 satellite images taken between 2017 and 2022 were used in both descending and ascending directions. The results revealed surface movements in the direction of the line of sight, ranging between −6 and 6 mm/year in the study area. Persistent Scatterer (PS) points were identified mainly in human structures such as roads, coasts, ports, and golf courses, especially in settlements. While some regions exhibited similar movements in both descending and ascending results, opposite movements were observed in some regions. The results produced in both descending and ascending directions were used together and decomposed into horizontal and vertical deformation components. It was observed that the western coastal part experienced approximately 4.5 cm/year vertical deformation, while the central part there is more significant horizontal deformation, reaching up to approximately 6 cm/year

Efficient production and enhanced tumor delivery of engineered extracellular vesicles

Extracellular vesicles (EV), including exosomes and microvesicles, are nano-sized intercellular communication vehicles that participate in a multitude of physiological processes. Due to their biological properties, they are also promising candidates for the systemic delivery of therapeutic compounds, such as cytokines, chemotherapeutic drugs, siRNAs and viral vectors. However, low EV production yield and rapid clearance of administered EV by liver macrophages limit their potential use as therapeutic vehicles. We have used a hollow-fiber bioreactor for the efficient production of bioactive EV bearing the heterodimeric cytokine complex Interleukin-15:Interleukin-15 receptor alpha. Bioreactor culture yielded ∼40-fold more EV per mL conditioned medium, as compared to conventional cell culture. Biophysical analysis and comparative proteomics suggested a more diverse population of EV in the bioreactor preparations, while serum protein contaminants were detectable only in conventional culture EV preparations. We also identified the Scavenger Receptor Class A family (SR-A) as a novel monocyte/macrophage uptake receptor for EV. In vivo blockade of SR-A with dextran sulfate dramatically decreased EV liver clearance in mice, while enhancing tumor accumulation. These findings facilitate development of EV therapeutic methods. © 201

SerpinB3 Drives Cancer Stem Cell Survival in Glioblastoma

Despite therapeutic interventions for glioblastoma (GBM), cancer stem cells (CSCs) drive recurrence. The precise mechanisms underlying CSC resistance, namely inhibition of cell death, are unclear. We built on previous observations that the high cell surface expression of junctional adhesion molecule-A drives CSC maintenance and identified downstream signaling networks, including the cysteine protease inhibitor SerpinB3. Using genetic depletion approaches, we found that SerpinB3 is necessary for CSC maintenance, survival, and tumor growth, as well as CSC pathway activation. Knockdown of SerpinB3 also increased apoptosis and susceptibility to radiation therapy. SerpinB3 was essential to buffer cathepsin L-mediated cell death, which was enhanced with radiation. Finally, we found that SerpinB3 knockdown increased the efficacy of radiation in pre-clinical models. Taken together, our findings identify a GBM CSC-specific survival mechanism involving a cysteine protease inhibitor, SerpinB3, and provide a potential target to improve the efficacy of GBM therapies against therapeutically resistant CSCs

Assessment of ALOS PALSAR 25-m mosaic data for land cover mapping

9th International Workshop on the Analysis of Multitemporal Remote Sensing Images, MultiTemp 2017 -- 27 June 2017 through 29 June 2017 -- -- 130873In this study, performance of the Global 25m resolution ALOS-PALSAR mosaic and forest/non-forest map generated by Japan Space Exploration Agency's - JAXA was addressed. PALSAR imagery has dual polarimetric data (HH and HV) and these dataset are open and freely available. An additional band applying difference of two polarizations (HH-HV) was added as a third band. For the study area most populated city of Turkey Istanbul is selected due to its rapid and dense expanse. For the evaluation 2010 and 2015 mosaic PALSAR data was classified using k-Nearest Neighbors (k-NN) method as a practical image classification approach. Moreover, an accuracy analysis for the forest/non-forest maps was also investigated to expose its misleading interpretation. A change detection analyses was conducted to estimate the changes from 2010 to 2015. In addition to these, the classified data was compared with 30m GlobeLand30 global data product. Results indicated that high rate classification result as 86% and 89% overall was obtained by k-NN with the three bands of ALOS-PALSAR mosaic data of 2010 and 2015, respectively. © 2017 IEEE.ACKNOWLEDGMENT The research is supported by the Bulent Ecevit University. The ALOS data is provided by JAXA and the GlobeLand30 data set is provided by the National Geomatics Center of China. (DOI:10.11769/GlobeLand30.2010.db)

Assessment of DEMs produced by medium resolution optical sensors considering land cover classes

ATHI TELECOM;e-geos;Thales Alenia Space;TELESPAZIO;SPACEALLIANCE33rd Asian Conference on Remote Sensing 2012, ACRS 2012 -- 26 November 2012 through 30 November 2012 -- Pattaya -- 97670A digital elevation model (DEM) presents immense data proving three dimensional terrain structure of any part of the Earth. DEMs are obtained by two main methods in space-borne remote sensing as stereoscopy using optical or radar imagery and interferometric synthetic aperture radar (InSAR) technology. In fact, the primary product of space-borne remote sensing techniques is a digital surface model (DSM) that contains points located on the top of ground objects. By removing these points that do not belong to the bare ground, the DEM is obtained. In optical imagery, DSMs are generated based on stereo matching using ground control points and co-located clear tie points at stereo image-pair with high correlation. In this case, correlation comes into prominence and affects the success of DSM acquired by stereoscopy. This investigation aims to assess the quality of DEMs produced by medium resolution spatial data derived from optical imagery depending upon the effect of correlation in stereoscopy correspondingly the land cover types. Towards this purpose, land cover classes have been generated such as open, forest, built-up, road network and rocky regions, DSM-DEM conversion was applied by optimal filtering methods and DEM accuracies have been achieved separately. The analyses were realized using actual ASTER GDEM Version 2 with 30m original grid spacing in Zonguldak, Turkey including rugged topography and suitable land cover classes. For the verification, a reference DEM derived from 1/1000 scaled aerial photos was employed

An assessment of urban area extraction using ALOS-2 data

Airbus;Aselsan;et al.;Roketsan;STM Engineering Technology Consultancy;Turkish Aerospace9th International Conference on Recent Advances in Space Technologies, RAST 2019 -- 11 June 2019 through 14 June 2019 -- -- 149874Urbanization has a dynamic structure especially in megacities and therefore rapid detection of the urban is vital for sustainable management of the city. In this work, we apply a multi-source feature data approach to investigate the urban area of Istanbul, Turkey which is a megacity with an approximate 15 million inhabitant, and under strong both anthropogenic and natural pressures. In order to analyse and compare the spatial pattern of the urban footprint, different techniques are applied. Speckle divergence, backscatter and repeat pass interferometric coherence values are considered for the analysis. To this aim, L-band HH and HV polarized ALOS-2 Synthetic Aperture Radar (SAR) data were acquired from Japan Space Exploration Agency's (JAXA). Pixel based Random Forest Classification method was used for the urban mapping. During the classification, different scenarios have been applied using speckle divergence, backscatter and coherence information. Overall, user and producer accuracies were calculated from the error matrix. While comparing HH and HV polarimetry, in each scenario HH provided much higher accuracies than HV results. Speckle divergence and backscatter values yielded similar accuracies which is around 88% for urban class. However, coherence gave approximately 69% while it is classified individually. The contribution of coherence was extracted while coherence was stacked with speckle divergence, and the result was improved to 91%. The urban areas was extracted with a maximum accuracy of maximum 93% while all information was combined. The preliminary results allow us to obtain a comprehensive image of urban structure, and indicate that the results may reference address for further analysis of multi-temporal SAR data over large and complicated mega cities. © 2019 IEEE

Data acquisition through the model aircraft for mapping purposes

2011 ISPRS Hannover Workshop on High-Resolution Earth Imaging for Geospatial Information -- 14 June 2011 through 17 June 2011 -- -- 111096Photogrammetry and remote sensing have become indispensable in today's surveying with the emerging technologies. Some difficulties are being experienced in applications due to the incredible advances in imaging systems and increasing complexity of carrier platforms, used, in parallel with them. In this context, the most agreeable approach is the achievement of desired precision proportional with the requirements in shorter time span and the reduction of cost utilizing the most suitable mapping platform with basic systems. Towards these aims, a model aircraft, containing a non-metric camera, capturing images for mapping purposes, is considered to be employed in this study. Thus, this will lead to emerge a low cost imaging system. Within the study, besides using a high resolution digital non-metric camera and a carrier model aircraft, the previously produced maps of test field, derived from aerial photos, were used to conduct the analysis. The scope of this study is the integration of a model aircraft and a non-metric camera for mapping purposes to reduce very costly and time consuming photogrammetric map production for narrower areas. Also this will give rise to a method for the achievement of high cost aims with lower budgets. Using a model aircraft, instead of a real one, gives us an upper hand in repeating measurements anytime, desired, so that analyses can be made for the works that undergoes temporal changes. According to the aims of the study, a stereo model has been generated for the extraction of details from aerial photos, taken by the non-metric camera. Estimated results have been compared with 1/1000 scaled maps from photogrammetry and figured out their validity for using in narrower areas with high accuracy

DATA ACQUISITION THROUGH THE MODEL AIRCRAFT FOR MAPPING PURPOSES

Photogrammetry and remote sensing have become indispensable in today's surveying with the emerging technologies. Some difficulties are being experienced in applications due to the incredible advances in imaging systems and increasing complexity of carrier platforms, used, in parallel with them. In this context, the most agreeable approach is the achievement of desired precision proportional with the requirements in shorter time span and the reduction of cost utilizing the most suitable mapping platform with basic systems. Towards these aims, a model aircraft, containing a non-metric camera, capturing images for mapping purposes, is considered to be employed in this study. Thus, this will lead to emerge a low cost imaging system. Within the study, besides using a high resolution digital non-metric camera and a carrier model aircraft, the previously produced maps of test field, derived from aerial photos, were used to conduct the analysis. The scope of this study is the integration of a model aircraft and a non-metric camera for mapping purposes to reduce very costly and time consuming photogrammetric map production for narrower areas. Also this will give rise to a method for the achievement of high cost aims with lower budgets. Using a model aircraft, instead of a real one, gives us an upper hand in repeating measurements anytime, desired, so that analyses can be made for the works that undergoes temporal changes. According to the aims of the study, a stereo model has been generated for the extraction of details from aerial photos, taken by the non-metric camera. Estimated results have been compared with 1/1000 scaled maps from photogrammetry and figured out their validity for using in narrower areas with high accuracy