Baigiamajame magistro darbe nagrinėjama geležinkelio pagrindo, tai yra žemės sankasų įrengimų technologija įvertinant vietos sąlygas. Sukuriami du žemės sankasų modeliai ant sauso pagrindo iš molingųjų ir drenuojančių gruntų, taip pat du modeliai durpynuose iš drenuojančių ir dulkingųjų gruntų, kurių gylis 4 m. Remiantis šiuo metu egzistuojančiais įkainiais buvo įvertintos pylimų iš skirtingų gruntų įrengimo kainos. Pylimams ant sauso pagrindo buvo sudarytas daugiakriteris sprendimo priėmimo uždavinys ir išspręstas 4 būdais: SAW, AHP, TOPSIS, MCDM-23. Naujausi darbai esantys mokslinių duomenų bazėse, Lietuvos institucijų pateikiama informacija, bei kita medžiaga internete tiriama analizės būdu; alternatyvų rodiklių reikšmės nustatomos remiantis praktika, bei kokybiniais mokslinio tyrimo metodais. Atlikus tyrimus priėita išvada, kad žemės sankasas 1 – o tipo geležinkeliams ant tvirto pagrindo arba pelkėse ekonomiškiau įrenginėti i�� dulkingųjų ar molingųjų gruntų. Darbą sudaro 7 dalys: 1) įvadas, 2) geležinkelių sankasų įrengimo reikšmė, 3) sankasų įrengimo technologinės alternatyvos, 4) skirtingų sankasų įrengimo technologijų modeliavimas, 5) daugiakriterių sprendimų priėmimo metodų aptarimas ir parinkimas, 6) išvados, 7) literatūros sąrašas. Darbo apimtis – 101 puslapių. / The master thesis covers the analysis of technology regarding the rail foundation or rail bed mounting in consideration of local conditions. Two rail bed models are designed over the dry foundation made of clayey and drained soil as well as two models in peatery made of drained and dusty soil at a depth of 4 m. The prices for mounting of embankment by using various soils were estimated with reference to the current prices. The thesis defined a multiple criteria task concerning the embankments over the dry foundation, which was solved in four ways: SAW, AHP, TOPSIS, MCDM-23. The new articles in academic databases, the information provided by Lithuanian institutions, and other material found in the Internet were examined with a help of analysis: the values of alternative indexes are determined in accordance to the practice and qualitative research methods. Research revealed that it is more efficient to mount the rail beds by utilizing drained and dusty soil over the solid foundation or in the peatery in case of the rails of the 1st type. The thesis consist of 7 sections: 1) introduction, 2) the importance of rail beds mounting, 3) technological alternatives for the rail beds mounting, 4) modeling of technologies for the different beds, 5) selection and consideration of multiple criteria solutions, 6) conclusions, 7) reference list. Thesis consist of 101 pages.

A Hamilton cycle in a graph is a cycle that passes through every vertex of the graph. A graph is called Hamiltonian if it contains such a cycle. In this thesis we investigate two classes of graphs, defined by local criteria. Graphs in these classes, with a simple set of exceptions K, were proven to be Hamiltonian by Asratian, Broersma, van den Heuvel, and Veldman in 1996 and by Asratian in 2006, respectively. We prove here that in addition to being Hamiltonian, graphs in these classes have stronger cyclic properties. In particular, we prove that if a graph G belongs to one of these classes, then for each vertex x in G there is a sequence of cycles such that each cycle contains the vertex x, and the shortest cycle in the sequence has length at most 5; the longest cycle in the sequence is a Hamilton cycle (unless G belongs to the set of exceptions K, in which case the longest cycle in the sequence contains all but one vertex of G); each cycle in the sequence except the first contains all vertices of the previous cycle, and at most two other vertices. Furthermore, for each edge e in G that does not lie on a triangle, there is a sequence of cycles with the same three properties, such that each cycle in the sequence contains the edge e.

This master report studies structural design methods for ice loads and the impact of local conditions. Ice loads occur due to ice movements or expansion of the ice sheet. Specifically, this study analyses ice loads on piled structures and ten different design methods and handbooks to calculate the ice load. There are five Swedish methods among these, and the remaining are developed in Denmark, Finland, Norway, and Germany. The methods are developed for different types of structures. For example, dams, bridge supports, traffic piers, ports and piles The ice loads have been divided into different categories; vertical ice loads and horizontal loads caused by thermal expansions, water level changes, or drifting ice. Some methods depend on local conditions parameters for the input data. These methods have been investigated in a parametric study to shed light on how different inputs affect the ice load. Some input data from local conditions have been developed and are presented to facilitate the design. Temperature and ice thickness are the parameters where most data are accessible. Furthermore, an evaluation has been performed on whether the methods are applicable for piles, if local conditions are considered, and if the method is practically applicable for ice load design. The size of the ice load is reported for different ice load types for three Swedish cities, namely Halmstad, Mora and Umeå. The overall result was that Mora generated the highest ice load magnitudes and Halmstad the lowest. A Finite Element (FE) analysis has been performed to address the affect that ice loads have on the dimensions of the piles. In general, more knowledge is needed about ice loads and their magnitude. Studies on what safety factors are included in each method need to be carried out to counteract unnecessarily applied safety factors in several stages. In addition, studies from a statistical perspective are required, where the return period of the input data used in the methods is studied. A statistical study would evaluate which values are justified in relation to the return period of the ice load. / I denna masteruppsats studeras dimensioneringsmetoder för islaster och hur lokala förhållanden inverkar på dessa. Islaster uppstår till följd av isens rörelser och expansion. Specifikt studeras islaster på pålade konstruktioner och tio olika handböcker och dimensioneringsmetoder för att bestämma islasten. Av dessa metoder är fem svenska metoder och de återstående är utvecklade i Danmark, Finland, Norge och Tyskland. Metoderna är anpassade för olika typer av konstruktioner; till exempel dammar, brostöd, trafikbryggor, hamnar och pålar. De studerade metoderna och dess tillvägagångssätt för att bestämma islast presenteras i examensarbetet. Islasterna har delats in i olika kategorier, vertikala islaster och de horisontella lasterna från termiska expansioner, vattenståndsförändringar och drivande is. En parameterstudie har genomförts för att belysa hur olika indata påverkar islasten storlek för de metoder som beaktar lokala förhållanden. Viss indata från lokala förhållanden har tagits fram samt presenteras för att underlätta islastberäkningar där temperatur och istjocklek är de parametrar där mest data finns att tillgå. Vidare har en utvärdering gjorts huruvida metoderna är applicerbara för pålade konstruktioner, om lokala förhållanden beaktas såväl som om metoderna är praktiskt tillämpbara vid islastdimensionering. Islastens storlek redovisas för olika islasttyper för de svenska städerna Halmstad, Mora och Umeå. Det övergripande resultatet av detta var att Mora genererade den största islasten och Halmstad den lägsta lasten. En Finita Element (FE) analys har genomförts för att belysa islastens påverkan på pålarnas dimensioner. Generellt behövs mer kunskap om islaster och dess storlek. Närmare studier skulle behöva genomföras gällande de säkerhetsfaktorer som inkluderas i respektive metod för att inte använda onödigt mycket säkerhetsfaktorer i fler led. Utöver detta behövs studier från ett statistiskt perspektiv där återkomstperioden av den indata som används i metoderna studeras och vilka värden som är befogade att använda i förhållande till islastens återkomstperiod.

Le paysage des rivières en tresses est constitué d’une riche mosaïque d’habitats diversifiés, déterminée par un ensemble de facteurs biophysiques qui interagissent à différentes échelles spatiales et temporelles.A partir d’une sélection de 53 tronçons en tresses, nous avons réalisé une analyse comparative à l’échelle régionale du bassin du Rhône et en fonction de plusieurs échelles temporelles, en mobilisant les techniques de télédétection.Premièrement, nous avons étudié la variabilité de la structure des habitats aquatiques et du patron des chenaux. Nous montrons que le patron de tressage et des habitats aquatiques n’est pas uniquement lié au débit, mais aussi aux conditions locales liées aux apports sédimentaires et à la présence de la nappe phréatique.Deuxièmement, nous avons abordé une approche diachronique afin de comprendre l’évolution à moyen terme du paysage fluvial de ces tronçons, depuis la moitié du siècle dernier. Les résultats montrent que toutes les tresses du bassin rhodanien ne sont pas déliquescentes et que certains tronçons sont encore très actifs. Cela dépend d’un ensemble de facteurs : la position géographique du tronçon, son évolution à court terme liée aux épisodes de crues et l’histoire des conditions anthropiques environnantes.Enfin nous avons analysé les trajectoires évolutives suivies par un sous-ensemble de 12 sites, analysés à une échelle temporelle plus fine (5 observations par site sur 50 ans). Nous observons que les tronçons suivent des trajectoires différentes, en fonction des conditions hydrologiques observables à un moment donnée (ex. crues), de la position géographique du tronçon et du contexte anthropique. De plus, certaines conditions locales (topographie et humidité relative) semblent aussi nécessaire à la compréhension du patron biogéomorphologique des tronçons étudiés.A partir de ces résultats des éléments de perspectives pour une gestion intégrée des rivières en tresses du district rhodanien sont proposés. / The landscape of the braided rivers is characterised by a rich and diversified mosaic of habitats. The variability of the braided riverscape depends upon the combination of bio-physical factors, which interact at the different spatial and temporal scales.We did a comparative analysis at the regional scale of 53 braided reaches selected in the Rhône basin district. We used a remote sensing-based approach.At first, we analysed the aquatic habitat and the river channel pattern. We showed that the braiding and aquatic habitat patterns do not depend only on the flow regime but also on some local scale conditions, such us the sediment regime and the presence of the “near-floor” groundwater.Secondly, we moved on the overall riverscape corridor, and we applied a diachronic analysis comparing the present state of reaches with their state at the mid of the last century. The results show that not all studied braided reaches are narrower today compared to the 1950s and that some reaches are even wider. It is linked to a combination of several factors, such as the geographical position of a reach in its catchment and the short-term evolution ruled by recent large floods, as well as the history of the catchment linked to human settlements.Then we focused on the evolutionary trajectories followed by a sub-set of 12 braided reaches through time, and we increased the temporal resolution, for a total of five dates per reach. The results show that reaches follow different trajectories depending on: the hydrological conditions at a given period (e.g. floods), the geographical position of a reach at the regional scale and the anthropic context. Additionally, it seems that also local conditions (in terms of topography, sedimentation, and soil moisture), play an important role in determining the biogeomorphological pattern of the studied reaches.From these results, we discussed some perspectives for the braided river management in the Rhône basin district.