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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.
11

Habitat selection by moose (Alces alces) in southwestern Sweden / Älgars habitatval i sydvästra Sverige

Olovsson, Anders January 2007 (has links)
The moose (Alces alces) is very important both economically and ecologically, therefore all knowledge of moose is vital for future management of the moose population. Little is known about moose habitat selection in Sweden. In coastal southwestern Sweden growing human population and new infrastructure projects continuously threaten to fragment and isolate local moose populations. The habitat selection of 22 moose, 8 males and 14 females, in southwestern Sweden was studied from February 2002 until December 2005. The moose were captured and fitted with GPS-collars and positions were collected at 2-hour intervals. The number of moose positions totaled 71103 during the study period of 46 months. Data for individual animals were divided into four seasons: spring, summer, fall and winter based on climate and moose biology. A total of 125 moose seasonal home ranges were generated and habitat use within each of the generated home ranges was studied using Euclidean distance-based analysis. A reclassified digital landcover map was divided into the land use classes agriculture, clear-cut, coniferous forest, deciduous forest, mire and mountain. The results showed that there was a difference in habitat selection between males and females. Males were significantly closer to forest and clear-cuts compared to females. Both males and females selected clear-cuts and avoided agriculture within their home ranges. / Älgen är en viktig art, både ekonomiskt och ekologiskt, och all kunskap är viktig för att även i framtiden kunna sköta en sund älgstam. Trots flertalet studier finns det många frågetecken om älgens habitatval i Sverige. En ökad exploateringstakt och nya infrastrukturprojekt hotar att fragmentera och isolera populationer av älg. Habitatvalet hos 22 älgar, 8 tjurar och 14 kor, i sydvästra Sverige studerades mellan februari 2002 och december 2005. Älgarna sövdes och utrustades med GPS-sändare, deras positioner registrerades varannan timma och det totala antalet positioner under den 46 månader långa studietiden var 71103 stycken. Data från varje älg delades in i 4 säsonger; vår, sommar, höst och vinter, baserat på klimat och älgens biologi. Totalt genererades 125 hemområden baserade på säsong, och valet av habitat inom varje hemområde studerades med hjälp av Euclidean distance-based analysis. En omklassificerad digital marktäckedata användes som var indelad i 6 olika klasser; odlad mark, hygge, barrskog, lövskog, myrmark och berg i dagen. Resultaten visade att det var skillnad mellan könen i hur de väljer habitat. Tjurarna var signifikant närmare barrskog och hyggen än korna, men både tjurar och kor selekterade för hyggen och undvek odlad mark inom deras hemområden.
12

Similarity Search And Analysis Of Protein Sequences And Structures: A Residue Contacts Based Approach

Sacan, Ahmet 01 August 2008 (has links) (PDF)
The advent of high-throughput sequencing and structure determination techniques has had a tremendous impact on our quest in cracking the language of life. The genomic and protein data is now being accumulated at a phenomenal rate, with the motivation of deriving insights into the function, mechanism, and evolution of the biomolecules, through analysis of their similarities, differences, and interactions. The rapid increase in the size of the biomolecular databases, however, calls for development of new computational methods for sensitive and efficient management and analysis of this information. In this thesis, we propose and implement several approaches for accurate and highly efficient comparison and retrieval of protein sequences and structures. The observation that corresponding residues in related proteins share similar inter-residue contacts is exploited in derivation of a new set of biologically sensitive metric amino acid substitution matrices, yielding accurate alignment and comparison of proteins. The metricity of these matrices has allowed efficient indexing and retrieval of both protein sequences and structures. A landmark-guided embedding of protein sequences is developed to represent subsequences in a vector space for approximate, but extremely fast spatial indexing and similarity search. Whereas protein structure comparison and search tasks were hitherto handled separately, we propose an integrated approach that serves both of these tasks and performs comparable to or better than other available methods. Our approach hinges on identification of similar residue contacts using distance-based indexing and provides the best of the both worlds: the accuracy of detailed structure alignment algorithms, at a speed comparable to that of the structure retrieval algorithms. We expect that the methods and tools developed in this study will find use in a wide range of application areas including annotation of new proteins, discovery of functional motifs, discerning evolutionary relationships among genes and species, and drug design and targeting.
13

A Multiple Criteria Sorting Approach Based On Distance Functions

Celik, Bilge 01 July 2011 (has links) (PDF)
Sorting is the problem of assignment of alternatives into predefined ordinal classes according to multiple criteria. A new distance function based solution approach is developed for sorting problems in this study. The distance to the ideal point is used as the criteria disaggregation function to determine the values of alternatives. These values are used to sort them into the predefined classes. The distance function is provided in general distance norm. The criteria disaggregation function is determined according to the sample preference set provided by decision maker. Two mathematical models are used in order to determine the optimal values and assign classes. The method also proposes an approach for handling alternative opt imal solutions, which are widely seen in sorting problems. Probabilities of belonging to each class for an alternative are calculated using the alternative optimal solutions and provided as the outputs of the model. Decision maker assigns the alternatives into classes according to these probabilities. The method is applied to five data sets and results are provided for different performance measures. Different distance norms are tried for each data set and their performances are evaluated for each data set. The probabilistic approach is also applied to UTADIS. The performance of the distance based model and modified UTADIS are compared with the previous sorting methods such as UTADIS and classification tree. The developed method has new aspects such as using distances to ideal point for sorting purpose and providing probabilities of belonging to classes. The handling of alternative optimal solutions within the method instead of a post-optimality analysis is another new and c ritical aspect of the study.
14

Projeções multidimensionais para a análise de fluxos de dados / Multidimensional projections for data stream analysis

Tácito Trindade de Araújo Tiburtino Neves 17 November 2016 (has links)
As técnicas de projeção multidimensional tornaram-se uma ferramenta de análise importante. Elas buscam mapear dados de um espaço multidimensional para um espaço visual, de menor dimensão, preservando as estruturas de distância ou de vizinhança no mapa visual produzido. Apesar dos recentes avanços, as técnicas existentes ainda apresentam deficiências que prejudicam a sua utilização como ferramentas exploratórias em certos domínios. Um exemplo está nos cenários streaming, nos quais os dados são produzidos e/ou coletados de forma contínua. Como a maioria das técnicas de projeção necessitam percorrer os dados mais de uma vez para produzir um layout final, e fluxos normalmente não podem ser carregados por completo em memória principal, a aplicação direta ou mesmo a adaptação das técnicas existentes em tais cenários é inviável. Nessa tese de doutorado é apresentado um novo modelo de projeção, chamado de Xtreaming, no qual as instâncias de dados são visitadas apenas uma vez durante o processo de projeção. Esse modelo é capaz de se adaptar a mudanças nos dados conforme eles são recebidos, atualizando o mapa visual para refletir as novas estruturas que surgem ao longo do tempo. Os resultados dos testes mostram que o Xtreaming é muito competitivo em termos de preservação de distâncias e tempo de execução se comparado com técnicas do estado-da-arte. Também é apresentada uma nova técnica de projeção multidimensional, chamada de User-assisted Projection Technique for Distance Information (UPDis), que foi projetada para permitir a intervenção do usuário exigindo apenas informações de distância entre as instâncias, e que é utilizada como parte do Xtreaming. Os resultados também mostram que a UPDis é tão rápida, precisa e flexível quanto as técnicas do estado-da-arte. / Multidimensional Projection techniques have become an important analytics tool. They map data from a multidimensional space into a visual space preserving the distance or neighborhood structures on the produced layout. Despite the recent advances, existing techniques still present drawbacks that impair their use as exploratory tools on certain domains. An example is the streaming scenario, in which data are captured or produced continuously. Since most projection techniques need to traverse the data more than once to produce a final layout, and streaming data typically cannot be completely loaded into the main memory, the direct use or even adaptation of the existing techniques in such scenarios is infeasible. In this dissertation, we present a novel projection model, called Xtreaming, wherein the data instances are visited only once during the projection process. This model is able to adapt itself to the changes in data as data is received, updating the visual layout to reflect the new structures that emerge over time. The tests show that Xtreaming is very competitive regarding distance preservation and running time when compared with state-of-the-art projection techniques. We also present a new multidimensional projection technique, called User-assisted Projection Technique for Distance Information (UPDis), that was designed to allow user intervention requiring only distance information between data instances. UPDis is used as part of the Xtreaming model. The results show that UPDis is as fast, accurate and flexible as state-of-the-art techniques.
15

Formation Control of Multi-Agent Systems

Mukherjee, Srijita 08 1900 (has links)
Formation control is a classical problem and has been a prime topic of interest among the scientific community in the past few years. Although a vast amount of literature exists in this field, there are still many open questions that require an in-depth understanding and a new perspective. This thesis contributes towards exploring the wide dimensions of formation control and implementing a formation control scheme for a group of multi-agent systems. These systems are autonomous in nature and are represented by double integrated dynamics. It is assumed that the agents are connected in an undirected graph and use a leader-follower architecture to reach formation when the leading agent is given a velocity that is piecewise constant. A MATLAB code is written for the implementation of formation and the consensus-based control laws are verified. Understanding the effects on formation due to a fixed formation geometry is also observed and reported. Also, a link that describes the functional similarity between desired formation geometry and the Laplacian matrix has been observed. The use of Laplacian matrix in stability analysis of the formation is of special interest.
16

Metody statistické inference založené na matici vzdáleností / Distance-based testing

Solnický, Radek January 2011 (has links)
When analyzing ecological data, one considers traditional multivariate techniques to be unsuitable. The use of dissimilarity coefficients and distance matrices is a way, how to solve this problem. In this work we present some of these coefficients and distance-based tests: Mantel test, several versions of ANOSIM and MRPP tests and distance-based test for homogeneity of multivariate dispersions. We focus on relationships among these tests and illustrate the use with an example. We also discuss the difficulties of interpretation of the results of these tests.
17

A projection of motor fuel tax revenue and analysis of alternative revenue sources in Georgia

Cherry, Phillip Warren 06 April 2012 (has links)
Transportation funding is critical to maintaining the assets that provide mobility for the movement of Georgia's people and goods. Currently, most of Georgia's transportation revenue is provided by the motor fuel tax. Inflation and recent increases in fuel economy have decreased fuel tax revenue in Georgia and weakened the Georgia Department of Transportation's (GDOT)'s ability to maintain and expand its transportation network. This thesis synthesizes factors from literature that affect motor fuel tax revenue. These include demographic, economic, technological, and environmental forces that influence travel behavior and vehicle fuel economy. A model was then created that incorporated these factors to model GDOT's 2009 fuel tax revenue and then project revenue in 2020 and 2030. The model uses an input/output structure that segments the fleet into personal, freight, and transit categories. User inputs, historical data, and projections are linked via relationships and feedback loops to project travel and fuel tax revenue forward. Because a near-infinite number of scenarios exist, conservative and aggressive scenarios were created for 2020 and 2030 scenarios that output revenue on an absolute, per-mile, and per-capita basis for comparison with more recent revenues. The model outputs predict marginal declines in revenue by 2020 and significant declines by 2030. In response to these declines, the thesis evaluates methods of increasing transportation revenue. These methods include increasing the fuel tax, incorporating a VMT-fee, and widespread tolling measures. After evaluation, a policy recommendation is provided for how to best implement revenue strategies.
18

Projektledning för kreativitet : En fallstudie om hur projektledare skapar förutsättningar för kreativitet i ett distansbaserat datorspelsutvecklingsprojekt / Project Management for Creativity : A Case Study on how Project Managers Promote Creativity in a Virtual Based Computer Game Development Project

Albonius, Jonas, Hagbok, Monica January 2014 (has links)
Companies and projects often face the challenge of creating something new to increase their competitiveness. In this process of creating something new creativity is an important factor. By using a creative approach and utilizing creative processes new innovations emerges. An industry that has grown in recent years is the computer games industry. Competition is fierce and for the companies to succeed, the product need that extra something to make it stand out among all the produced games. The project manager's role in the creative process and the ability to be creative within a distance based company is not something highlighted by previous research. This formed the basis of our research question: How do project managers act to create conditions for creativity among employees in a remotely organized computer game company? To answer our question, we chose to make a descriptive case study. The project is based in the Nordic countries with employees worldwide. It is altogether a distance based project with no shared workspace. We interviewed the projects two project managers, and supplemented with a qualitative survey amongst the employees. The collected material was analyzed with a methodology inspired by Grounded Theory and previous research results. Three approaches of how the project managers act to promote creativity are evident in their stories. These approaches are trust, availability and tolerance. They form the basis of our model on how the project managers in this case act to promote employee creativity. Besides the three approaches, two concepts emerged as important tools for creativity in the project: motivation and communication. Our conclusion can be described as follows: Motivation provides the conditions for creative thinking. By building an organization where project leaders show trust in the ability of employees, and allows tolerance to be a watchword for collaboration, project managers work to improve employee motivation. This will create opportunities for creativity among the employees in this distance based project. Communication is essential for creative work in the project and virtual means of communication a way to increase availability. / Företag och projekt ställs ofta inför utmaningen att skapa något nytt för att till exempel öka sin konkurrenskraft. I processen att ta fram denna nya produkt är kreativitet en viktig faktor. Med hjälp av ett kreativt förhållningssätt och en kreativ process kan nya innovationer växa fram. En bransch som växt mycket de senaste åren är datorspelsbranschen. Konkurrensen är hård och om företagen ska lyckas krävs det att produkten har något extra som gör att det sticker ut bland alla spel som produceras. Projektledarens roll i kreativitetsprocessen är ett område som tidigare forskning inte har belyst särskilt mycket. Inte heller har möjligheten att skapa förutsättningar för kreativitet inom ett distansbaserat företag behandlats särskilt mycket. Studiens forskningsfråga är: Hur agerar projektledare för att skapa förutsättningar för kreativitet hos projektmedarbetare i ett distansbaserat datorspelsutvecklingsprojekt? För att besvara vår frågeställning valde vi att göra en deskriptiv fallstudie. Projektet har sin bas i Norden med medarbetare över hela världen. Det är helt och hållet ett distansbaserat projekt på så sätt att ingen delar arbetsplats. Vi djupintervjuade projektets två projektledare och kompletterade med en kvalitativ enkät till medarbetarna. Med en utgångspunkt i Grounded Theory och tidigare forskningsresultat analyserades materialet. Ur projektledarnas berättelser framträdde tre förhållningssätt. Dessa är tillit, tillgänglighet och tolerans. De ligger till grund för vår modell om hur projektledarna i det undersökta fallet agerar för att främja kreativiteten hos medarbetarna. Dessutom visade det sig att motivation och kommunikation var två viktiga verktyg för att skapa förutsättningar för kreativitet hos medarbetarna. Vår slutsats kan beskrivas på följande sätt: Motivation ger förutsättningar för kreativt tänkande. Genom att bygga en organisation där projektledarna visar tillit till medarbetarnas förmåga, och låter tolerans vara ett ledord för kollaboration, arbetar projektledarna för att höja medarbetarnas motivation. Därmed skapas förutsättningar för kreativitet hos medarbetarna i detta distansbaserade projekt. Kommunikation är en förutsättning för kreativt skapande i projektet och virtuella kommunikationsmedel ett sätt att öka tillgängligheten.
19

Thriving towards extreme openness : A way of facilitating Fuzzy front-end activities by using communication technology

Mohammed, Leila, Lidén, Matilda January 2020 (has links)
Purpose – This study has two different purposes. First, we aim to understand and describe the new phenomenon of extreme openness within the area of open innovation by answering the following question: How can this new concept of extreme openness within the Fuzzy front-end be understood and described? The second purpose of this study is to investigate how Fuzzy front-end activities can be held at a distance by answer the following question: Which technology-based communication can facilitate distance-based Fuzzy front-end activities? Method – This study was conducted as an abductive single case-study of the Fuzzy front-end process where extreme openness is performed at a multinational conglomerate company. Interviews have been held with both employees at the case company as well as external actors.  In total, 41 interviews were conducted, where 35 were unique respondents. The results were generated through the use of thematic analysis.  Findings – The findings from the study are summarized in two different frameworks in which the first framework explains the phenomenon of extreme openness and gives insight into why and how large companies provide innovation power to external actors. The second framework illustrates which communication technologies to use in the Fuzzy front-end process and provide necessary information about needed functionality and criteria when having Fuzzy front-end activities distance-based.  Theoretical and practical implications – The study provides implications for research on open innovation by empirically explicating the new phenomenon of extreme openness and connect the open innovation literature with the social exchange theory. Our findings reveal that business-to-business relational exchange can result in future benefits and that top managers can use this strategy to build long-term relationships and achieve financial improvements. Further, we also provide implications into the research on the Fuzzy front-end by empirically clarifying functionality and criteria that are specifically needed when having these activities distance-based. Our result provides implications relevant to both top managers and project managers. Limitations and future research – The study is limited by a single case study of the new phenomenon of extreme openness and which communication technology to use in distance-based Fuzzy front-end activities. We recommend future research to validate and extend findings from this study in new contexts.
20

Non-centralized distributed algorithm to locate nearby servers based on player positions for a MMOG server cluster

Östman, Alexander January 2015 (has links)
In this thesis a non-centralized algorithm is proposed to locate nearby servers based on their players’ positions in a massive multiplayer online game server cluster. The purpose of this is to enable that players can visually see each other even though they are connected to different servers. By utilizing peer to peer connection between the servers the algorithm is tolerant against possible hardware failures. The algorithm simplifies the data sent over the network with a new concave polygon creation algorithm which works in linear execution time, enabling fast computations for real-time games. The algorithm works by finding colliding polygons from other servers and the closest polygons based on distance to find nearby servers which information should be shared with. Those two algorithms at this time work in quadratic execution time which is a point of improvement, which could require the concave polygon to be converted into one or several convex polygons. The algorithm is designed to give the user good access on the amount of network traffic sent over the cluster which gives better control and understanding on how much network traffic that will be sent in the cluster. It shows that the algorithm is dependent on how players in the world are distributed over the servers. By having players nearby each other on the same server improves the result of the algorithm. It is shown that compared to having a centralized server, the network traffic on every single node have reduced network traffic than compared to a centralized server. / In den här uppsatsen presenteras en icke-centraliserad algoritm som hittar närliggande servrar baserat på deras spelares positioner i ett massivt multi-spelare online spel med flera servrar. Syftet är att möjliggöra att spelare från olika servrar kan se varandra visuellt även fast de är uppkopplade till olika servrar. Genom att använda sig av ”peer-to-peer” kommunikation i klustret blir algoritmen tolerant mot hårdvarufel. Algoritmen simplifierar data som skickas genom en ny typ av konkav polygon algoritm vilken fungerar i linjär exekveringstid, vilket möjliggör snabba beräkningar för realtidsspel. Algoritmen fungerar genom att hitta kolliderande polygoner från andra servrar och även de mest närliggande baserat på distans för att lokalisera närliggande servrar att dela information med. De här två algoritmerna arbetar i kvadratisk tid vilket skulle kunna förbättras. Detta kan kräva att konkava polygonen konverteras till en eller flera konvexa polygoner. Algoritmen är designad för att ge användaren bra tillgång till hur mycket nätverkstrafik som bör skickas inom klustret vilket ger en bättre kontroll och förståelse över hur mycket data som kommer att skickas totalt. Det visas att algoritmen är beroende av hur spelarna är distribuerade över servrarna. Genom att ha närliggande spelare i världen på samma server förbättras resultatet av algoritmen. Det visas även att jämfört med en centraliserad server så förbättras nätverkstrafiken på varje enskild nod jämfört med trafiken som mottogs av den centraliserade servern.

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