In this article, we propose a new grid-free and exact solution method for computing solutions associated with an hybrid traffic flow model based on the Lighthill- Whitham-Richards (LWR) partial differential equation. In this hybrid flow model, the vehicles satisfy the LWR equation whenever possible, and have a fixed acceleration otherwise. We first present a grid-free solution method for the LWR equation based on the minimization of component functions. We then show that this solution method can be extended to compute the solutions to the hybrid model by proper modification of the component functions, for any concave fundamental diagram. We derive these functions analytically for the specific case of a triangular fundamental diagram. We also show that the proposed computational method can handle fixed or moving bottlenecks.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21308号 / 工博第4506号 / 新制||工||1701(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 清水 芳久, 教授 伊藤 禎彦 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

In the friction stir welding (FSW) process, heat and mechanical work are coupled to produce a solid state weld. The process variables are pin tool rotation speed, translational weld speed, and downward plunge force. The strain-temperature history of a metal element at each point on the cross-section of the weld is determined by the process variables plus the individual flow path taken by the particular filament of metal flowing around the tool and ending on that point. The strain-temperature history determines the properties of a metal filament on the weld cross-section. To control the mechanical properties, the strain-temperature history must be carefully controlled. Indirect estimates of the flow paths and the strain-temperature histories of filaments comprising friction stir welds can be made from a model, if the model provides sufficient information. This paper describes experimental marker studies designed to trace the metal flow streamlines as influenced by variations in the process parameters.

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no / In this paper, a performance analysis of adaptive routing is presented for packet-switched inter-satellite link (ISL)networks, based on shortest path routing and two alternate link routing forwarding policies. The selected routing algorithm and link-cost function are evaluated for a low earth orbit satellite system, using a demographically weighted traffic flow model. Two distinct traffic flow patterns are modelled: hot spot and regional. Performance analysis, in terms of quality of service and quantity of service, is derived using specifically developed simulation software to model the ISL network, taking into account topology adaptive routing only, or topology and traffic adaptive routing.

Thesis (DPhil (Logistics))--University of Stellenbosch, 2007. / South Africa currently experiences the double jeopardy problem of catching up to global economic competitiveness whilst at the same time feeling the pressures of sustainability management spearheaded by a global agenda. Global sustainability is defined as growth that is shared without depleting natural resources or damaging the environment. Academic disciplines are challenged to make a contribution and economics as such should contribute by providing the lead and lag indicators for the planning and measurement of scarce resources usuage. This integrative view includes economic sub-disciplines, such as logistics. This integrative view is an acknowledged part of the economics discipline, except that the macro-economic context of some sub-disciplines, such as logistics, often receives less attention during the course of academic activities. The distribution of resources and outputs in the economy is a logistics controlled cross-cutting factor, but suffers from a lack of macro-economic perspective, and lead and lag orientated measurement. This state of the affairs is a historic backlog of logistics and its specific position within economics. During the primary economic era the world began to configure networks and markets, which became more pronounced and settled with the dawn and settling of the industrial era. Logistics then was a “given” and did not receive much thought even as industrial, market economies developed. Transport was regarded as an administered cost, i.e. inefficiencies in logistics systems were evenly distributed between competitors, not giving any specific entity an advantage. With the advent of global competition and the diminishing returns on other cost saving measures, companies began to collaborate and integrate logistics functions within value chains, but the administered part of transport costs failed to receive the attention it required. In this way, global competitors did begin to experience disadvantages on a national level as whole economies suffered from inefficiencies in logistics and specifically transport systems.

Översvämningar till följd av intensiva nederbördstillfällen har de senaste åren ökat i antal och omfattning. Dessa händelser förväntas bli vanligare i framtiden och skapa fler översvämningar. Med anledning av detta är det intressant att undersöka hur översvämningar i framtiden breder ut sig och vilka vattennivåer som bildas med förväntad nederbörd. Att modellera översvämningar kräver data som i vissa fall kan vara både tidskrävande och omständig att införskaffa. Möjliga avgräsningar och antaganden i modellparametrar kan då vara intressanta att göra som fortfarande ger användbara resultat. En skyfallskartering har genomförts med 2D-hydraulisk modellering i Kumla med programvaran MIKE 21 Flow Model FM. De översvämningskartor som skapades användes för att identifiera områden i Kumla som riskerar att drabbas av höga vattennivåer till följd av skyfall motsvarande 100- och 200-årsregn. En stor osäkerhet vid modellering av översvämningar är att validera resultaten som fås fram. Ofta saknas information om tidigare översvämningar. De nederbördstillfällen som används är ofta så stora att det saknas data om liknande händelser tidigare. Vid översvämningsmodellering anväds data som beskriver olika typer av modellparametrar. Dessa kommer med ytterligare osäkerheter som kan göra valideringen problematisk. För att undersöka hur stor effekt olika modellparametrar har på resultatet genomfördes en känslighetsanalys där differenskartor skapades mellan undersökta scenarion och referenskartor. Skyfallskarteringen visade att stora delar i Kumla drabbas av översvämningar för både ett 100- och 200-årsregn. Området Kumlaby identifierades som känsligt och får höga vattennivåer. Detta beror mest troligt på omgivningens topografi och att Kumlaby underlagras av leror med låg infiltrationskapacitet. I känslighetsanalysen identifierades markens råhet och infiltrationskapacitet vara styrande parametrar för översvämningens utbredning och vattennivåer. Dessa påverkar främst hur höga vattenflöden som uppstår och översvämningens utbredningen och vattennivåer. Kunskap om dessa parametrar är viktigt för att undvika över- eller underskattning av en översvämning. Användningen av avrinningskoefficienter istället för markens råhet, infiltrationskapacitet och evaporation undersöktes. Differensen i översvämningens utbredning och vattennivåer blev stor i och utanför Kumla tätort. På mindre områden kan det vara mer lämpligt att använda en avrinningskoefficient när en mer detaljerad klassning kan göras av de markytor som finns. Ett scenario som undersöktes i känslighetsanalysen var installation av gröna tak på alla byggnader i Kumla. Simuleringarna som genomfördes visade att både utbredningen och vattennivåer minskade. Detta till följd av större lagringskapacitet och motstånd mot vattenflöden som kommer med gröna tak. / Urban floods caused by intense rainfall have occurred more frequently the last couple of years. These rainfall events are expected to become more common in the future and create more floods in urban areas. This makes it important to investigate the extent and water levels from urban floods in the future. In order to simulate floods, different types of data is needed. This data can be both time consuming and difficult to obtain. With this in mind, it is interesting to investigate possible simplifications and assumptions of model parameters. A cloud burst mapping was made with 2D hydraulic modelling in Kumla with the software MIKE 21 Flow Model FM. The flood maps created were used to identify areas in Kumla which have a higher risk of being subject to high water levels. One uncertainty while modelling urban floods is the process of validating the results. There is often a lack of data for the used rainfall events or information from previous floods in the area. In flood modelling data is used which describes different model parameters, these comes with additional uncertainties and can make the validation more difficult. A sensitivity analysis was made to be able to examine effects on the results from variations in model parameters. The cloud burst mapping showed that large parts of Kumla will be affected by water levels which goes up to 1 m. The area Kumlaby was identified as being sensitive for high water levels. This is due to placement of Kumlaby below higher ground which causes water to flow toward Kumlaby. The ground below is mostly made up of clay which has low infiltration capacity. In the sensitivity analysis the bed resistance and infiltration capacity were identified as governing parameters regarding the extent and water levels of urban floods. In order to avoid over- or underestimation of floods it is important to have knowledge about these parameters in the model area. The use of a runoff coefficient instead of bed resistance, infiltration and evaporation were examined. The difference of the resulting flood were large in the whole model area. In smaller areas a runoff coefficient could be used with better results when a more detailed description can be made of the surfaces in the area. A scenario where green roofs were assumed to have been installed on all buildings in Kumla were examined. The simulations showed that both the extent and water levels decreased. This due to the fact that green roofs have a capacity to store water and delay flows of water.

With an intensification of heavy rain events in a changing climate and a rapid urbanization the risk for pluvial flooding is increasing in our societies. Pluvial flooding, which is formed when the rainfall rate exceeds the infiltration or drainage rate, can occur rapidly and cause great damages, large economic losses and possibly risk human lives. This kind of flooding is difficult to predict since it is caused by short-term and often local processes, but preventive measures and more robust infrastructure developed over the last decades have decreased the risk of the most severe damages. One way to prevent damage is to map risk areas and take measures by performing a cloudburst modelling, which can be done as a 2D hydraulic modelling. Common practice in cloudburst modelling today is to use a uniform design storm, often the Chicago Design Storm (CDS), with the same hyetograph applied evenly over the whole model area. Even though rain is not spatially uniform this assumption might be valid for more stratiform frontal rain. Intense rain events however have a higher spatial variation in rain intensity, and an assumption like this might significantly affect the results. This study aimed to investigate the effect of the spatial variation in rain intensity on the modelled hydraulic response from an intense rain event. It was performed through a case study of the cloudburst in Gävle, Sweden, in August 2021. A 2D hydraulic model of the city was prepared in the software MIKE 21 Flow Model FM and the cloudburst event was simulated with a spatially varied rainfall input, based on radar data from the event with a 2x2 km resolution, and with spatially uniform rainfall input both with the temporal variation in rain intensity from the event and with a Chicago Design Storm, all with the same total volume. The scenarios were evaluated in terms of proportion of the model area being flooded, the average maximum flooding depth and by mapping the difference in flooding depth over the whole area. The results showed that the spatial variation of rainfall input had a significant effect on the hydraulic response in the city and that assuming a uniform rainfall might lead to an underestimation of the flooding depths in parts of the model area compared to a varied one. The average flooding depth was only a few percent higher for the spatially varied rain compared to the uniform rain with a similar time variation, but in large central areas of the city the model with the uniform rain underestimated the maximum flooding depth by 5-35%. The uniform CDS rain was seen to both over- and underestimate the flooding depth, but in the central and flooded parts of the city underestimation dominated. This points out a risk of using uniform design storms in cloudburst modelling, since a spatially varied rain of the same volume could give more severe effects than the simulated response and that using a uniform design storm potentially introduces an uncertainty in the modelled results that could be important to point out and further quantify. / Med en intensifiering av häftiga regnväder i ett förändrat klimat och en allt snabbare urbanisering ökar risken för pluviala översvämningar i våra samhällen. Pluviala översvämningar, som skapas av att regnintensiteten är högre än infiltrations- eller dräneringshastigheten, kan uppstå plötsligt och orsaka stora skador, ekonomiska förluster och även i värsta fall riskera människoliv. Denna typ av översvämning är svår att förutse eftersom den orsakas av snabba och ofta lokala processer, men förebyggande åtgärder och mer robust infrastruktur som har utvecklats de senaste decennierna har minskat risken för de allvarligaste skadorna. Ett sätt att förebygga skador är att kartera riskområden genom skyfallsmodellering, till exempel med en tvådimensionell hydraulisk modell. Praxis idag är att använda spatialt uniforma typregn vid skyfallsmodellering, där samma hyetograf appliceras jämnt över hela modellområdet. Detta antagande kan ge giltiga resultat för mer stratiforma frontregn, men intensiva regn, skyfall, har generellt sett en hög spatial variation i intensiteten vilket gör att antagandet skulle kunna påverka resultatet signifikant. Denna studie syftade till att undersöka effekten av den spatiala variationen i regnintensitet på den simulerade hydrauliska responsen från ett intensivt regn och den utfördes som en fallstudie av skyfallet i Gävle 17-18 augusti 2021. En 2D hydraulisk modell av Gävle förbereddes i programmet MIKE 21 Flow Model FM och simuleringar utfördes med en spatialt varierad regnindata, baserad på radardata från tillfället med en 2x2 km upplösning, och med spatialt uniforma regnindata både med den verkliga tidsvariationen och med en Chicago Design Storm (CDS), alla med samma totala volym. Skillnaden mellan scenarierna utvärderades genom att jämföra andel översvämmat modellområde, medel av maximala översvämningsdjupet och en kartering av skillnaden i översvämningsdjup över hela modellområdet. Resultaten visade att den spatiala variationen i regnindatan hade en signifikant effekt på den simulerade hydrauliska responsen i staden och att antagande om uniform regnintensitet kan leda till en underskattning av översvämningsdjupen i modellområdet jämfört med ett varierat regn. Medelvärdet av översvämningsdjupet var endast några procent högre  för det spatialt varierade regnet, men i stora centrala områden underskattade modellen med det uniforma regnet det maximala översvämningsdjupet med 5-35 %. Det uniforma CDS-regnet både under- och överskattade översvämningsdjupet, men i centrala och översvämmade områden var det större delar som underskattades. Detta visar på en risk med att använda uniforma typregn i skyfallsmodellering, då ett spatialt varierat regn med samma volym skulle kunna ge betydligt allvarligare effekter än de som modellen har visat och att användandet av uniforma testregn potentiellt inför en osäkerhet i resultaten som är viktig att poängtera och även att vidare undersöka och kvantifiera.

Life insurance policies are not equally profitable is sense of expected value. In practice, profitability is an output of complex cash flow models, which need utilizing special systems and the run time of such calculation can be significant if number of policies is high. Therefore we consider variables, which change most frequently, stimulate the profitability model with several values of these variables and then we search for a regression model to explain the changes. We apply Gamma regression on the data. But what if there exist some policies which are negative? Then we determine these policies with logistic regression applied on data censored to the binary form. Loss of these policies is modelled using symmetrical Gamma model. These three models, when considered together, can be viewed as a single model, which is a generalization of the well known zero inflated count model. The most interesting part of inference in such model is diagnostics. We show that the basic types of residuals - Pearson, deviance and quantile - can be defined. We also build an ordinary linear model and we compare utility of these two approaches. While building models, we meet various statistical issues like dimension reduction of yield curve or dispersion proportional to sum insured. 1