Using ArcticDEM to analyse the dimensions and dynamics of debris-covered glaciers in Kamchatka, Russia

On the Kamchatka Peninsula, a number of glaciers are covered by thick volcanic debris, which makes their margins difficult to delineate from satellite imagery. Fortunately, high resolution, multi-temporal digital surface models (DSMs) covering the entire peninsula have recently become freely available (i.e., ArcticDEM). We use these DSMs to analyse the dimensions and dynamics of debris-covered glaciers in the northern Kluchevskoy Volcanic Group, central Kamchatka. This approach demonstrates that between 2012 and 2016, some of the region’s glaciers advanced despite regional and local climate warming. These glacial advances are part of a long-term trend, presumed to reflect the role of extensive supraglacial debris in limiting ice ablation, though there is also evidence for local ice melt due to supraglacial lava/debris flows. Glacier surface velocities during the period 2012–2015 were typically 5–140 m yr−1. Velocities for the major outlets of the region’s central icefield were typically higher than for other extensively debris-covered glaciers globally, likely reflecting the influence of ice supply from the high altitude Ushkovsky caldera. In all, we find ArcticDEM useful for analysing debris-covered glaciers in Kamchatka, providing important information on flow dynamics and terminus change that is difficult to derive from satellite imagery

Multiscale approach of retinal blood vessels segmentation based on vessels segmentation with different scales

In this work, the authors developed retinal blood vessels segmentation approach using contrast limited adaptive histogram equalization, morphological filtering, k-means clustering, matched filtering for thin and thick vessels selection. The authors also applied matched filtering for thin vessels selection using the kernels which were built in order to determine the existence of line segments with different length and orientatio

Walkability: Implementation Challenges in the Suburbs of North Central Texas

This thesis focuses on walkability efforts and implementation challenges in one of the suburbs of North Central Texas, the City of Plano, by exploring two mixed-use walkable developments and conducting interviews with local planners, developers, and academics. While the city has recognized the need for improved development patterns and has allowed higher-density, mixed-use development in designated Urban Centers, there is still a disconnect between the city's objectives and the actual implementation. Site visits to Shops at Legacy and Downtown Plano identified discrepancies including path context and connectivity, segregated uses, quality of the pedestrian realm, continued prioritization of vehicles and minimal density increases. Interviews revealed that one the biggest challenges in the City of Plano is, and will continue to be, the city's urban form. Observations and interviews presented in this thesis reveal that the City of Plano will most likely never be able to achieve walkability on a citywide level, nor would that be the desired outcome. Recommendations are made for potential retrofits throughout one of the sites in order to improve walkability and ultimately create cohesive livability

Analysis of thick and thin vessel pixel clustering for retinal blood vessel image segmentation

In this work, we revealed that digital image processing is an actual topic at present and it is widely used in various fields of medicine, including diagnosis of the eye fundus. An analysis of the dependence of the blood vessel segmentation results on the image of the eye fundus from various partitions to pixel classes corresponding to thick and thin vessels obtained by k-means clustering was mad

Impact of being evergreen or deciduous on the wood anatomy of the trees in polar regions during the warm geological period : case study from Upper Cretaceous of the James Ross Island (Antarctic Peninsula)

Změny prostředí v důsledku globálního oteplovaní a jejich následky jsou podstatnou a široce studovanou otázkou. Křídové polární ekosystémy nemají v dnešní době obdobu. Proto takové ekosystémy představují unikátní možnost pro studium extrémních prostředí a organizmů se specifickými adaptacemi na ně. Příslušné ekosystémy mohou mít klíčový význam pro pochopení možných budoucích změn na naší planetě. Diplomová práce se věnuje otázce strategie adaptace suchozemských rostlin v období pozdní křídy: stálezeleností a opadavostí. Studovaný materiál pochází z oblasti Brandy Bay a Crame Col na ostrově Jamese Rosse u Antarktického poloostrova a byl sbírán v souvislém sledu profilů od souvrství Kotick Point po souvrství Santa Marta (cenonam až kampán). Ze studovaných 55 vzorků fosilních dřev bylo vybráno a systematicky popsáno pět typických taxonů jehličnanů pro dané geologické období a oblast: Agathoxylon kellerense, Agathoxylon antarcticus, Araucarioxylon chapmanae, Podocarpoxylon multiparenchymatosum a Phoroxylon sp. Agathoxylon kellerense (vzorek číslo AN34) byl vybrán pro detailní analýzu a zjištění strategie adaptace jehličnanů na základě anatomické stavby letokruhů. Metodou stanovení strategie adaptace rostliny (procentuální zmenšení buněk; procentuální zastoupení letního dřeva; RMI; náklon CSDM křivky)...Global warming and its influence on the environment has become a popular and widespread issue. Nowadays, an analogy of a high latitude ecosystem during the greenhouse type of climate does not exist. The Cretaceous polar ecosystem gave us a unique possibility of understanding these extreme ecosystems and the specific adaptations of organisms to these conditions. Such types of ecosystem are crucial for a better understanding of possible future climate changes. This thesis focusses on the adaptation strategies of land plants during the Late Cretaceous in the Arctic peninsula. The land plants responded to these specific solar conditionals in two different ways: evergreen or deciduous. The fossil material for this study comes from Brandy Bay and Crame Col, James Ross Island, Antarctic. The material was collected in a continuous sequence from Kotic point to Santa Marta Formation (Cenomanian - Companian). A detailed and systematic analysis was performed on five out of fifty-five samples that well represented the studied region and age: Agathoxylon kellerense, Agathoxylon antarcticus, Araucarioxylon chapmanae, Podocarpoxylon multiparenchymatosum and Phoroxylon sp. Based on the detailed study of Agathoxylon kellerense (sample number AN34) wood anatomy and growth rings structure, adaptation strategies were...Institute of Geology and PaleontologyÚstav geologie a paleontologiePřírodovědecká fakultaFaculty of Scienc

SEA SURFACE IMAGE SUB-BAND ANALYSIS BASED ON COSINE TRANSFORM

Subject of Research. We propose an approach to the research of the frequency properties of the sea surface images sequence (video frames) on the basis of sub-band analysis within the cosine transform. The study of frequency properties makes it possible to solve the problem of object detection on the agitated sea surface. Method. The main theoretical propositions of the sub-band analysis within the cosine transform are given. The paper presents the method of formation of the cosine transform sub-band matrices used in data analysis and method of calculation of the analyzed vector energy parts in different frequency intervals. The sub-band approach to the analysis of the image component energy distribution in the frequency domain is described. Realization of separate components of the sea surface image sequence (video frames) in the vector form is shown. The vectors contain the pixel values with the same coordinates in the image set and give the possibility to calculate the energy parts in specified frequency intervals. Main Results. Video of the sea surface with various agitation levels were used in computing experiments. The distribution analysis of the energy part values of the matching components in the used video records showed that different sea surface agitation corresponds to different distributions of the matching component energy in the frequency domain. It has been found that at low agitation, the energy of the image components is concentrated in the low-frequency region and with the increase of the sea surface agitation, the energy part values of the corresponding image components increase in the high-frequency region. Practical Relevance. The obtained distribution features of the sea surface image component energy parts can be used when solving the detection problems for objects, floating on the sea surface, based on the analysis of their frequency characteristics

Subband analysis and synthesis of signals

Currently, a wide class of modern wireless telecommunications systems is based on the use of broadband signals. The problems of synthesis for their formation and processing algorithm are extremely important for such systems, especially under the conditions of various types of disturbances, which is impossible without scientifically based analysis of signal propertie