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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Uncertainty Analysis : Severe Accident Scenario at a Nordic Nuclear Power Plant

Hedly, Josefin, De Young, Mikaela January 2023 (has links)
Nuclear Power Plants (NPP) undergo fault and sensitivity analysis with scenario modelling to predict catastrophic events, specifically releases of Cesium 137 (Cs-137). The purpose of this thesis is to find which of 108 input-features from Modular Accident Analysis Program (MAAP)simulation code are important, when there is large release of Cs-137 emissions. The features are tested all together and in their groupings. To find important features, the Machine learning (ML) model Random Forest (RF) has a built-in attribute which identifies important features. The results of RF model classification are corroborated with Support Vector Machines (SVM), K-Nearest Neighbor (KNN) and use k-folds cross validation to improve and validate the results, resulting in a near 90% accuracy for the three ML models. RF is successful at identifying important features related to Cs-137 emissions, by using the classification model to first identify top features, to further train the models at identifying important input-features. The discovered input-features are important both within their individual groups, but also when including all features simultaneously. The large number of features included did not disrupt RF much, but the skewed dataset with few classified extreme events caused the accuracy to be lower at near 90%.
122

An in-core grid index for transferring finite element data across dissimilar meshes

Scrimieri, Daniele, Afazov, S.M., Ratchev, S.M. January 2015 (has links)
The simulation of a manufacturing process chain with the finite element method requires the selection of an appropriate finite element solver, element type and mesh density for each process of the chain. When the simulation results of one step are needed in a subsequent one, they have to be interpolated and transferred to another model. This paper presents an in-core grid index that can be created on a mesh represented by a list of nodes/elements. Finite element data can thus be transferred across different models in a process chain by mapping nodes or elements in indexed meshes. For each nodal or integration point of the target mesh, the index on the source mesh is searched for a specific node or element satisfying certain conditions, based on the mapping method. The underlying space of an indexed mesh is decomposed into a grid of variable-sized cells. The index allows local searches to be performed in a small subset of the cells, instead of linear searches in the entire mesh which are computationally expensive. This work focuses on the implementation and computational efficiency of indexing, searching and mapping. An experimental evaluation on medium-sized meshes suggests that the combination of index creation and mapping using the index is much faster than mapping through sequential searches.
123

Comparing Text Similarity Functions For Outlier Detection : In a Dataset with Small Collections of Titles

Rabo, Vide, Winbladh, Erik January 2022 (has links)
Detecting when a title is put in an incorrect data category can be of interest for commercial digital services, such as streaming platforms, since they group movies by genre. Another example of a beneficiary is price comparison services, which categorises offers by their respective product. In order to find data points that are significantly different from the majority (outliers), outlier detection can be applied. A title in the wrong category is an example of an outlier. Outlier detection algorithms may require a metric that quantify nonsimilarity between two points. Text similarity functions can provide such a metric when comparing text data. The question therefore arises, "Which text similarity function is best suited for detecting incorrect titles in practical environments such as commercial digital services?" In this thesis, different text similarity functions are evaluated when set to detect outlying (incorrect) product titles, with both efficiency and effectiveness taken into consideration. Results show that the variance in performance between functions generally is small, with a few exceptions. The overall top performer is Sørensen-Dice, a function that divides the number of common words with the total amount of words found in both strings. While the function is efficient in the sense that it identifies most outliers in a practical time-frame, it is not likely to find all of them and is therefore deemed to not be effective enough to by applied in practical use. Therefore it might be better applied as part of a larger system, or in combination with manual analysis. / Att identifiera när en titel placeras i en felaktig datakategori kan vara av intresse för kommersiella digitala tjänster, såsom plattformar för filmströmning, eftersom filmer delas upp i genrer. Också prisjämförelsetjänster, som kategoriserar erbjudanden efter produkt skulle dra nytta. Outlier detection kan appliceras för att finna datapunkter som skiljer sig signifikant från de övriga (outliers). En titel i en felaktig kategori är ett exempel på en sådan outlier. Outlier detection algoritmer kan kräva ett mått som kvantifierar hur olika två datapunkter är. Text similarity functions kvantifierar skillnaden mellan textsträngar och kan därför integreras i dessa algoritmer. Med detta uppkommer en följdfråga: "Vilken text similarity function är bäst lämpad för att hitta avvikande titlar i praktiska miljöer såsom kommersiella digitala tjänster?”. I detta examensarbete kommer därför olika text similarity functions att jämföras när de används för att finna felaktiga produkttitlar. Jämförelsen tar hänsyn till både tidseffektivitet och korrekthet. Resultat visar att variationen i prestation mellan funktioner generellt är liten, med ett fåtal undantag. Den totalt sett högst presterande funktionen är Sørensen-Dice, vilken dividerar antalet gemensamma ord med det totala antalet ord i båda texttitlarna. Funktionen är effektiv då den identiferar de flesta outliers inom en praktisk tidsram, men kommer sannolikt inte hitta alla. Istället för att användas som en fullständig lösning, skulle det därför vara fördelaktigt att kombinera den med manuell analys eller en mer övergripande lösning.
124

Predicting Bridge Deck Condition Ratings Using K-Nearest Neighbors Algorithm for National Bridge Inventory

Pallepogu, Avinash January 2022 (has links)
No description available.
125

An Application of the Nearest Neighbour Technique: Patterns of Urban Places in Southern Saskatchewan

Ingram, David Richard 05 1900 (has links)
The patterns of certain groups of urban places, selected on the basis of population size and area location, in southern Saskatchewan are classified by the use of the nearest neighbour technique. Through a study of the variations within the overall pattern, which are revealed by differences in the derived pattern statistic, a partial contribution is made to the understanding of the distributive process that underlies the observed settlement pattern. Explanations for the variations in the nature of the spatial arrangement of the various groups of places are suggested through the use of multivariate analysis, and by reference to theoretical and empirical works in the field of Central Place Theory. / Thesis / Master of Arts (MA)
126

The effect of FORTIFIED home designation on property value

Gould, Leslie 07 August 2020 (has links)
Due to the serious impact wind damage has on homes in the Gulf Coast region, policy makers, community developers, and homeowners are seeking ways to lessen impacts. One potential tool to increase properties’ resiliency in the event of a periodic and catastrophic event is wind mitigation, the process of adding features to a building, i.e. a house, to increase the strength of the structure amid a storm such as a hurricane. In this research, I evaluate the tiers of FORTIFIED homes as the mitigation strategies. I use Zillow ZTRAX and Institute of Business and Home Safety data to estimate how each level of FORTIFIED home designation affects property value. The results show FORTIFIED Gold designation on a new home has a 0%-8.4% increase on property value. I place my finding into a BCA of FORTIFIED designation to evaluate how this one benefit fits into the greater picture.
127

Hierarchical Statistical Models for Large Spatial Data in Uncertainty Quantification and Data Fusion

Shi, Hongxiang January 2017 (has links)
No description available.
128

NEAREST NEIGHBOR SEARCH IN DISTRIBUTED DATABASES

KUMAR, SUSMIT 11 June 2002 (has links)
No description available.
129

AN ALL-ATTRIBUTES APPROACH TO SUPERVISED LEARNING

VANCE, DANNY W. January 2006 (has links)
No description available.
130

Identifying Interesting Posts on Social Media Sites

Seethakkagari, Swathi, M.S. 21 September 2012 (has links)
No description available.

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