• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 1
  • Tagged with
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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.
1

Using SNPs to study complex genetic disease : a population and evolutionary genetics perspective /

Sawyer, Sarah Lynn, January 2004 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.
2

Demographic Evolution Modeling System for Activity-Based Travel Behavior Analysis and Demand Forecasting

January 2014 (has links)
abstract: The activity-based approach to travel demand analysis and modeling, which has been developed over the past 30 years, has received tremendous success in transportation planning and policy analysis issues, capturing the multi-way joint relationships among socio-demographic, economic, land use characteristics, activity participation, and travel behavior. The development of synthesizing population with an array of socio-demographic and socio-economic attributes has drawn remarkable attention due to privacy and cost constraints in collecting and disclosing full scale data. Although, there has been enormous progress in producing synthetic population, there has been less progress in the development of population evolution modeling arena to forecast future year population. The objective of this dissertation is to develop a well-structured full-fledged demographic evolution modeling system, capturing migration dynamics and evolution of person level attributes, introducing the concept of new household formations and apprehending the dynamics of household level long-term choices over time. A comprehensive study has been conducted on demography, sociology, anthropology, economics and transportation engineering area to better understand the dynamics of evolutionary activities over time and their impacts in travel behavior. This dissertation describes the methodology and the conceptual framework, and the development of model components. Demographic, socio-economic, and land use data from American Community Survey, National Household Travel Survey, Census PUMS, United States Time Series Economic Dynamic data and United States Center for Disease Control and Prevention have been used in this research. The entire modeling system has been implemented and coded using programming language to develop the population evolution module named `PopEvol' into a computer simulation environment. The module then has been demonstrated for a portion of Maricopa County area in Arizona to predict the milestone year population to check the accuracy of forecasting. The module has also been used to evolve the base year population for next 15 years and the evolutionary trend has been investigated. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2014
3

Evolutionary dynamics, topological disease structures, and genetic machine learning

Gryder, Ryan Wayne 06 October 2021 (has links)
Topological evolution is a new dynamical systems model of biological evolution occurring within a genomic state space. It can be modeled equivalently as a stochastic dynamical system, a stochastic differential equation, or a partial differential equation drift-diffusion model. An application of this approach is a model of disease evolution tracing diseases in ways similar to standard functional traits (e.g., organ evolution). Genetically embedded diseases become evolving functional components of species-level genomes. The competition between species-level evolution (which tends to maintain diseases) and individual evolution (which acts to eliminate them), yields a novel structural topology for the stochastic dynamics involved. In particular, an unlimited set of dynamical time scales emerges as a means of timing different levels of evolution: from individual to group to species and larger units. These scales exhibit a dynamical tension between individual and group evolutions, which are modeled on very different (fast and slow, respectively) time scales. This is analyzed in the context of a potentially major constraint on evolution: the species-level enforcement of lifespan via (topological) barriers to genomic longevity. This species-enforced behavior is analogous to certain types of evolutionary altruism, but it is denoted here as extreme altruism based on its potential shaping through mass extinctions. We give examples of biological mechanisms implementing some of the topological barriers discussed and provide mathematical models for them. This picture also introduces an explicit basis for lifespan-limiting evolutionary pressures. This involves a species-level need to maintain flux in its genome via a paced turnover of its biomass. This is necessitated by the need for phenomic characteristics to keep pace with genomic changes through evolution. Put briefly, the phenome must keep up with the genome, which occurs with an optimized limited lifespan. An important consequence of this model is a new role for diseases in evolution. Rather than their commonly recognized role as accidental side-effects, they play a central functional role in the shaping of an optimal lifespan for a species implemented through the topology of their embedding into the genome state space. This includes cancers, which are known to be embedded into the genome in complex and sometimes hair-triggered ways arising from DNA damage. Such cancers are known also to act in engineered and teleological ways that have been difficult to explain using currently very popular theories of intra-organismic cancer evolution. This alternative inter-organismic picture presents cancer evolution as occurring over much longer (evolutionary) time scales rather than very shortened organic evolutions that occur in individual cancers. This in turn may explain some evolved, intricate, and seemingly engineered properties of cancer. This dynamical evolutionary model is framed in a multiscaled picture in which different time scales are almost independently active in the evolutionary process acting on semi-independent parts of the genome. We additionally move from natural evolution to artificial implementations of evolutionary algorithms. We study genetic programming for the structured construction of machine learning features in a new structural risk minimization environment. While genetic programming in feature engineering is not new, we propose a Lagrangian optimization criterion for defining new feature sets inspired by structural risk minimization in statistical learning. We bifurcate the optimization of this Lagrangian into two exhaustive categories involving local and global search. The former is accomplished through local descent with given basins of attraction while the latter is done through a combinatorial search for new basins via an evolution algorithm.
4

Socio-economic Impact of Fiber to the Home in Sweden

Xiong, Ziyi January 2013 (has links)
Fiber-to-the-Home (FTTH) has been talked about since the introduction of fiberin the 1970s. It is nowadays shaping up to be the foundation of our newdigital society, bringing economic prosperity and a multitude of business,social, and entertainment opportunities to its users. The increased consumerdemand for high-speed network accessibility is being taken more and moreseriously and a fiber-based network is able to cope with these growing demandsdue to its wide bandwidth and reliability. Today there is a practical need forquantitative analysis regarding the socio-economic impacts of fiber-basedaccess networks. This analysis could be used as an indicator/reference for allthe stakeholder entities as they consider future investments anddevelopments. Sweden is a suitable target country for this analysis since ithas adopted fiber for some years and the benefits that FTTH has brought seemto already be tangible. The primary value of this thesis lies ininvestigation of its quantified evidence of the socio-economic impacts of FTTHdeployment in Sweden. This has been achieved based on data from the SwedishPost and Telecommunications Authority (PTS), Statistics Sweden (SCB), previousrelated studies, and information collected on-line from operators involved inthe fiber market, along with empirical analysis based on multivariateregression models. The results of the study show that fiber penetrationhas had a significant impact on the population’s evolution, specially the netamount of migration into a municipality, which indicates the attractiveness ofmunicipalities per se. It is therefore reasonable to suggest that localgovernment and local authorities take fiber deployment into consideration, ifthey want to attract people to stay for further local development. The studyalso analyzed the competition in fiber-based open networks and the prices ofsubscribing for 10/10 Mbps symmetrical Internet Service. Study findingsrevealed that networks with multiple competing service providers have a widerrange of services and a lower price: the more ISPs competing in a fibernetwork, the lower consumer prices. Specifically, for each new serviceprovider present in the network, there will be 5 SEK per month decrease of theaverage price of the Internet services, and an approximately 7 SEK per monthreduction in the lowest price. Nevertheless, a number of socio-economicimpacts remain unquantifiable as of the current time and due to the limitedavailable data. It is recommended to incorporate more socio-economic effectsin future research in order to draw a more complete picture for all theinterested sectors, and to supplement the data with recent figures for 2012and 2013. / Fiber till hemmet (Fiber-to-the-Home, FTTH) har talats om sedan fiberintroducerades på 1970-talet. Det håller numera på att bli grunden för vårtnya digitala samhälle, och bidra till ekonomiskt välstånd och medföra en mängdaffärsmässiga, sociala och underhållningsmässiga möjligheter tillslutanvändare. Den ökade efterfrågan på höghastighetsnät tas mer och mer påallvar och ett fiberbaserat nät kan hantera dessa ökade krav på grund av dessbreda bandbredd och tillförlitlighet. Idag finns ett praktiskt behov avkvantitativ analys av de socioekonomiska effekterna av fiberbaseradeaccessnät. Denna analys kan användas som en indikator och referens för allaintressenter när de överväger framtida investeringar. Sverige är ett lämpligtmålland för denna analys eftersom den har antagit fiber i några år och defördelar som FTTH har fört verkar redan vara synliga. Det huvudsakligavärdet av denna avhandling ligger i utredningen av kvantifierade bevis för desocioekonomiska effekterna av FTTH utbyggnad i Sverige. Detta har uppnåtts pågrundval av uppgifter från den Post- och telestyrelsen (PTS), Statistiskacentralbyrån (SCB), tidigare liknande studier och information som samlats inpå nätet från aktörer inom fiber, tillsammans med empirisk analys baserad påmultivariate regressionsmodeller. Resultatet visat att fiber har haft enbetydande inverkan på befolkningens utveckling, speciellt netto in- ochutflyttning till en kommun, vilket indikerar attraktionskraft kommunerna isig. Det är därför rimligt att föreslå att kommunerna och de lokalamyndigheterna överväger fiber driftsättning på allvar om de vill lockainvånare att stanna för ytterligare lokal utveckling. Studien analyserar ocksåkonkurrensen på fiberbaserade öppna nät och priserna på 10/10 Mbps symmetriskInternet-tjänst. Resultaten visar att nätverk med flera konkurrerandetjänsteleverantörer har ett bredare utbud av tjänster och ett lägre pris: jufler Internetleverantörer i ett fibernät, desto lägre konsumentpriser. Merspecifikt, för varje ny tjänsteleverantör som finns i nätverket, minskar detgenomsnittliga priset med 5 kronor per månad, och det lägsta priset med cirka7 kronor per månad. Ändå förblir ett antal socioekonomiska effekteromätbara på grund av begränsade tillgängliga data. Rekommendationen är attinförliva fler socioekonomiska effekter i framtida forskning för att dra enmer komplett bild för alla berörda sektorer, och att komplettera data medfärska siffror för 2012 och 2013.

Page generated in 0.1395 seconds