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  • 101.
    He, Changli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Teräsvirta, Timo
    Properties of moments of a family of GARCH processes1999In: Journal of Econometrics, ISSN 0304-4076, E-ISSN 1872-6895, Vol. 92, no 1, p. 173-192Article in journal (Refereed)
    Abstract [en]

    This paper considers the moments of a family of first-order GARCH processes. First, a general condition for the existence of any integer moment of the absolute values of the observations is given. Second, a general expression for this moment as a function of lower-order moments is derived. Third, the kurtosis and the autocorrelation function of the squared and absolute-valued observations are derived. The results apply to a number of different GARCH parameterizations. Finally, the existence, or lack thereof, of the theoretical counterpart to the so-called Taylor effect in some members of this GARCH family is discussed. Possibilities of extending the results to higher-order GARCH processes are indicated and potential applications of the statistical theory proposed.

  • 102.
    He, Changli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Teräsvirta, Timo
    Gónzalez, Andrés
    Testing parameter constancy in stationary vector autoregressive models against continuous change2008In: Econometric Reviews, ISSN 0747-4938, E-ISSN 1532-4168, Vol. 28, no 1-3, p. 225-245Article in journal (Refereed)
    Abstract [en]

    In this article we derive a parameter constancy test of a stationary vector autoregressive model against the hypothesis that the parameters of the model change smoothly over time. A single structural break is contained in this alternative hypothesis as a special case. The test is a generalization of a single-equation test of a similar hypothesis proposed in the literature. An advantage here is that the asymptotic distribution theory is standard. The performance of the tests is compared to that of generalized Chow-tests and found satisfactory in terms of both size and power.

  • 103. Husby, Arild
    et al.
    Kawakami, Takeshi
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics. SLU.
    Smeds, Linnéa
    Ellegren, Hans
    Qvarnström, Anna
    Genome-wide association mapping in a wild avian population identifies a link between genetic and phenotypic variation in a life-history trait2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1806Article in journal (Refereed)
    Abstract [en]

    Understanding the genetic basis of traits involved in adaptation is a major challenge in evolutionary biology but remains poorly understood. Here, we use genome-wide association mapping using a custom 50 k single nucleotide polymorphism (SNP) array in a natural population of collared flycatchers to examine the genetic basis of clutch size, an important life-history trait in many animal species. We found evidence for an association on chromosome 18 where one SNP significant at the genome-wide level explained 3.9% of the phenotypic variance. We also detected two suggestive quantitative trait loci (QTLs) on chromosomes 9 and 26. Fitness differences among genotypes were generally weak and not significant, although there was some indication of a sex-by-genotype interaction for lifetime reproductive success at the suggestive QTL on chromosome 26. This implies that sexual antagonism may play a role in maintaining genetic variation at this QTL. Our findings provide candidate regions for a classic avian life-history trait that will be useful for future studies examining the molecular and cellular function of, as well as evolutionary mechanisms operating at, these loci.

  • 104.
    Håkansson, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Statistics.
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Statistics.
    Does euclidian distance work when location models are applied in rural areas?2010Report (Other academic)
  • 105.
    Jia, Tao
    et al.
    Wuhan University.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Trips and their CO2 emissions induced by a shopping center2013Report (Other academic)
    Abstract [en]

    Most previous studies have focused on entire trips in a geographic region, while a few of them addressed trips induced by a city landmark. Therefore paper explores trips and their CO2 emissions induced by a shopping center from a time-space perspective and their usage in relocation planning. This is conducted by the means of a case study in the city of Borlänge in mid-Sweden where trips to the city’s largest shopping mall in its center are examined. We use GPS tracking data of car trips that end and start at the shopping center. Thereafter, (1) we analyze the traffic emission patterns from a time-space perspective where temporal patterns reveal an hourly-based traffic emission dynamics and where spatial patterns uncover a heterogeneous distribution of traffic emissions in spatial areas and individual street segments. Further, (2) this study reports that most of the observed trips follow an optimal route in terms of CO2 emissions. In this respect, (3) we evaluate how well placed the current shopping center is through a comparison with two competing locations. We conclude that the two suggested locations, which are close to the current shopping center, do not show a significant improvement in term of CO2 emissions.

  • 106.
    Jia, Tao
    et al.
    School of Remote Sensing and Information Engineering, Wuhan University.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Trips and their CO2 emissions to and from a shopping center2013In: Journal of Transport Geography, ISSN 0966-6923, E-ISSN 1873-1236, Vol. 33, p. 135-145Article in journal (Refereed)
    Abstract [en]

    Previous studies have focused on entire trips within a geographical region, while only a few have examined trips to and from a city landmark. This paper examines trips (and their CO2 emissions) to and from a shopping center from a time-space perspective, and it further considers how this information can be used in relocation planning. It is a case study in the Borlänge city in mid-Sweden where trips to the city’s largest shopping mall are scrutinized. We use GPS tracking data of car trips starting and ending at the shopping center. Firstly, we analyze the traffic emission patterns from a time-space perspective where the temporal patterns reveal hourly-based traffic emission dynamics. The spatial analysis uncovers a heterogeneous distribution of areal traffic emissions as well as of single street segments. Secondly, we find the observed trips mostly agree with an optimal route in terms of CO2 emissions. Drawing on this finding, we thirdly evaluate the location of the current shopping center by comparing it to two competing locations. We conclude that the two competing locations, being in the vicinity of the current one, would induce an insignificant improvement in terms of CO2 emissions.

  • 107.
    Jia, Tao
    et al.
    Högskolan i Gävle.
    Jiang, Bin
    Högskolan i Gävle.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Statistics.
    Bohlin, Magnus
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Ban, Yifang
    KTH.
    An empirical study on human mobility and its agent-based modeling2012In: Journal of Statistical Mechanics: Theory and Experiment, ISSN 1742-5468, E-ISSN 1742-5468, article id P11024Article in journal (Refereed)
    Abstract [en]

    This paper aims to analyze the GPS traces of 258 volunteers for a better understanding of both the human mobility patterns and the mechanism. We report the regular and scaling properties of human mobility from several aspects, and importantly we find its levy flight characteristic which is consistent with the previous studies. We further assume two factors that may govern the levy flight property: (1) the scaling and hierarchical properties of the purpose clusters which serve as the underlying spatial structure, and (2) the individual preferential behavior. To verify the assumptions, we implement an agent-based model with the two factors, and the simulated agents indeed reproduce the same levy flight pattern as the observed one. In order to enable the model to reproduce more mobility patterns, we add the model a third factor, the jumping factor which means the probability that one person may cancel the regular mobility schedule and visit a random place. With this factor, our model could cover a relatively wide range of human mobility patterns with exponent values from 1.55 to 2.05.

  • 108.
    Karim, Hawzheen
    et al.
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Alam, Moudud
    Dalarna University, School of Technology and Business Studies, Statistics.
    Magnusson, Rolf
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Road barrier repair costs and influencing factors2011In: Journal of transportation engineering, ISSN 0733-947X, E-ISSN 1943-5436, Vol. 137, no 5, p. 349-359Article in journal (Refereed)
    Abstract [en]

    This paper presents a study that examines repair costs for different road barrier types and factors that influence these costs. The analyses focused on w-beam and cable barriers used as median barriers. To some extent, pipe barriers, Kohlswa-beam barriers, and concrete barriers were also studied. The influencing factors included in this study were road type, speed limit, barrier type, and seasonal effects. A case study was conducted in four regions of the Swedish Road Administration. Data were collected from 1,625 barrier repairs carried out during 2005 and 2006. The results show that the number of barrier repairs and the average repair cost per vehicle kilometer are higher along collision-free roads than along motorways and 4-lane roads. The results also show that the number of barrier repairs and the average repair cost per vehicle kilometer are higher for cable barrier than for other barrier types. No conclusion can be drawn regarding influence of speed limits on barrier repairs and associated costs as the result from the regions are divergent and not statistically significant. DOI: 10.1061/(ASCE)TE.1943-5436.0000227. (C) 2011 American Society of Civil Engineers.

  • 109. Lee, Youngjo
    et al.
    Alam, Moudud
    Dalarna University, School of Technology and Business Studies, Statistics.
    Noh, M
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Skarin, Anna
    Analyzing spatially correlated counts with excessive zeros: a case of modeling the changes of reindeer distribution2013Report (Other academic)
  • 110. Lee, Youngjo
    et al.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Noh, Maengseok
    Data Analysis Using Hierarchical Generalized Linear Models with R2017Book (Other academic)
  • 111.
    Li, Dao
    Dalarna University, School of Technology and Business Studies, Statistics. Handelshögskolan vid Örebro universitet, Statistik.
    Common Features in Vector Nonlinear Time Series Models2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of four manuscripts in the area of nonlinear time series econometrics on topics of testing, modeling and forecasting nonlinear common features. The aim of this thesis is to develop new econometric contributions for hypothesis testing and forecasting in these area.

    Both stationary and nonstationary time series are concerned. A definition of common features is proposed in an appropriate way to each class. Based on the definition, a vector nonlinear time series model with common features is set up for testing for common features. The proposed models are available for forecasting as well after being well specified.

    The first paper addresses a testing procedure on nonstationary time series. A class of nonlinear cointegration, smooth-transition (ST) cointegration, is examined. The ST cointegration nests the previously developed linear and threshold cointegration. An Ftypetest for examining the ST cointegration is derived when stationary transition variables are imposed rather than nonstationary variables. Later ones drive the test standard, while the former ones make the test nonstandard. This has important implications for empirical work. It is crucial to distinguish between the cases with stationary and nonstationary transition variables so that the correct test can be used. The second and the fourth papers develop testing approaches for stationary time series. In particular, the vector ST autoregressive (VSTAR) model is extended to allow for common nonlinear features (CNFs). These two papers propose a modeling procedure and derive tests for the presence of CNFs. Including model specification using the testing contributions above, the third paper considers forecasting with vector nonlinear time series models and extends the procedures available for univariate nonlinear models. The VSTAR model with CNFs and the ST cointegration model in the previous papers are exemplified in detail,and thereafter illustrated within two corresponding macroeconomic data sets.

  • 112.
    Li, Dao
    Dalarna University, School of Technology and Business Studies, Statistics.
    Residual-based Inference for Common Nonlinear Features2013Report (Other academic)
    Abstract [en]

    This paper investigates common nonlinear features in multivariate nonlinear autore-gressive models via testing the estimated residuals. A Wald-type test is proposed and itis asymptotically Chi-squared distributed. Simulation studies are given to examine thefinite-sample properties of the proposed test.

  • 113.
    Li, Dao
    Dalarna University, School of Technology and Business Studies, Statistics.
    Residual-based test for Nonlinear Cointegration with application in PPPs2008Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Nested by linear cointegration first provided in Granger (1981), the definition of nonlinear cointegration is presented in this paper. Sequentially, a nonlinear cointegrated economic system is introduced. What we mainly study is testing no nonlinear cointegration against nonlinear cointegration by residual-based test, which is ready for detecting stochastic trend in nonlinear autoregression models. We construct cointegrating regression along with smooth transition components from smooth transition autoregression model. Some properties are analyzed and discussed during the estimation procedure for cointegrating regression, including description of transition variable. Autoregression of order one is considered as the model of estimated residuals for residual-based test, from which the test statistic is obtained. Critical values and asymptotic distribution of the test statistic that we request for different cointegrating regressions with different sample sizes are derived based on Monte Carlo simulation. The proposed theoretical methods and models are illustrated by an empirical example, comparing the results with linear cointegration application in Hamilton (1994). It is concluded that there exists nonlinear cointegration in our system in the final results.

  • 114.
    Li, Dao
    Dalarna University, School of Technology and Business Studies, Statistics.
    Testing linear cointegration against smooth-transition cointegration2011Report (Other academic)
    Abstract [en]

    This paper studies a smooth-transition (ST) type cointegration. The proposed ST cointegration allows for regime switching structure in a cointegrated system. It nests the linear cointegration developed by Engle and Granger (1987) and the threshold cointegration studied by Balke and Fomby (1997). We develop F-type tests to examine linear cointegration against ST cointegration in ST-type cointegrating regression models with or without time trends. The null asymptotic distributions of the tests are derived with stationary transition variables in ST cointegrating regression models. And it is shown that our tests have nonstandard limiting distributions expressed in terms of standard Brownian motion when regressors are pure random walks, while have standard asymptotic distributions when regressors contain random walks with nonzero drift. Finite-sample distributions of those tests are studied by Monto Carlo simulations. The small-sample performance of the tests states that our F-type tests have a better power when the system contains ST cointegration than when the system is linearly cointegrated. An empirical example for the purchasing power parity (PPP) data (monthly US dollar, Italy lira and dollar-lira exchange rate from 1973:01 to 1989:10) is illustrated by applying the testing procedures in this paper. It is found that there is no linear cointegration in the system, but there exits the ST-type cointegration in the PPP data.

  • 115.
    Li, Dao
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    He, Changli
    Dalarna University, School of Technology and Business Studies, Statistics.
    Forecasting with Vector Nonlinear Time Series Models2013Report (Other academic)
    Abstract [en]

    This work concerns forecasting with vector nonlinear time series models when errorsare correlated. Point forecasts are numerically obtained using bootstrap methods andillustrated by two examples. Evaluation concentrates on studying forecast equality andencompassing. Nonlinear impulse responses are further considered and graphically sum-marized by highest density region. Finally, two macroeconomic data sets are used toillustrate our work. The forecasts from linear or nonlinear model could contribute usefulinformation absent in the forecasts form the other model.

  • 116.
    Li, Dao
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    He, Changli
    Dalarna University, School of Technology and Business Studies, Statistics.
    Testing common nonlinear features in vector nonlinear autoregressive models2012Report (Other academic)
    Abstract [en]

    This paper studies a special class of vector smooth-transition autoregressive (VSTAR) models that contains common nonlinear features (CNFs), for which we proposed a triangular representation and developed a procedure of testing CNFs in a VSTAR model. We first test a unit root against a stable STAR process for each individual time series and then examine whether CNFs exist in the system by Lagrange Multiplier (LM) test if unit root is rejected in the first step. The LM test has standard Chi-squared asymptotic distribution. The critical values of our unit root tests and small-sample properties of the F form of our LM test are studied by Monte Carlo simulations. We illustrate how to test and model CNFs using the monthly growth of consumption and income data of United States (1985:1 to 2011:11).

  • 117. Marjanovic, Jovana
    et al.
    Mulder, Han A
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics. SLU.
    Bijma, Piter
    Modelling the co-evolution of indirect genetic effects and inherited variability2018In: Heredity, ISSN 0018-067X, E-ISSN 1365-2540, Vol. 121, p. 631-647Article in journal (Refereed)
    Abstract [en]

    When individuals interact, their phenotypes may be affected not only by their own genes but also by genes in their social partners. This phenomenon is known as Indirect Genetic Effects (IGEs). In aquaculture species and some plants, however, competition not only affects trait levels of individuals, but also inflates variability of trait values among individuals. In the field of quantitative genetics, the variability of trait values has been studied as a quantitative trait in itself, and is often referred to as inherited variability. Such studies, however, consider only the genetic effect of the focal individual on trait variability and do not make a connection to competition. Although the observed phenotypic relationship between competition and variability suggests an underlying genetic relationship, the current quantitative genetic models of IGE and inherited variability do not allow for such a relationship. The lack of quantitative genetic models that connect IGEs to inherited variability limits our understanding of the potential of variability to respond to selection, both in nature and agriculture. Models of trait levels, for example, show that IGEs may considerably change heritable variation in trait values. Currently, we lack the tools to investigate whether this result extends to variability of trait values. Here we present a model that integrates IGEs and inherited variability. In this model, the target phenotype, say growth rate, is a function of the genetic and environmental effects of the focal individual and of the difference in trait value between the social partner and the focal individual, multiplied by a regression coefficient. The regression coefficient is a genetic trait, which is a measure of cooperation; a negative value indicates competition, a positive value cooperation, and an increasing value due to selection indicates the evolution of cooperation. In contrast to the existing quantitative genetic models, our model allows for co-evolution of IGEs and variability, as the regression coefficient can respond to selection. Our simulations show that the model results in increased variability of body weight with increasing competition. When competition decreases, i.e., cooperation evolves, variability becomes significantly smaller. Hence, our model facilitates quantitative genetic studies on the relationship between IGEs and inherited variability. Moreover, our findings suggest that we may have been overlooking an entire level of genetic variation in variability, the one due to IGEs.

  • 118.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Statistics.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Quality control of waste to incineration: waste composition analysis in Lidköping2005In: Waste Management & Research, ISSN 0734-242X, E-ISSN 1096-3669, Vol. 23, no 6, p. 527-533Article in journal (Refereed)
    Abstract [en]

    In order to decrease environmental impacts in waste management the choice of treatment method must be based on the characteristics of the waste. Present sampling procedures do not provide statistically representative samples of solid waste and this provides difficulties in characterization. The objective of this study was to develop a procedure for waste component analysis and sampling of waste after collection and at plant level. A further objective was to characterize the waste delivered to an incineration plant for physical and chemical properties and to determine the amounts of delivered waste that could be classified as biofuels and fossil fuels. The proportions of recyclables and hazardous waste were also examined. Samples were taken randomly from waste trucks and divided by square implementation. Statistical analysis of the results showed that the number of sub-samples could be decreased with only a moderate increase in the confidence interval. This means that future waste composition analyses could be made more efficient and thereby less expensive. The analysis of the waste delivered to the Lidkoping incineration plant (Central Sweden) showed that 66.4% of the household waste was composed of biofuels and 21.3% of non-renewable combustibles, of which 40.3% were recyclables. In addition, 11.6% of the household waste was non-combustible and 0.6% hazardous waste. The heat value for the biofuels was 18.0-19.7 MJ kg(-1) dry mass (DM) and for the fossil fuels 28.2-33.9 MJ kg(-1) DM. The industrial waste consisted of 35.9% biofuels, 62.0% fossil fuels, 1.6% non-combustible and 0.5% hazardous waste. The heat value was 19.5 MJ kg(-1) DM for the biofuels and 31.4 MJ kg(-1) DM for the fossil fuels.

  • 119.
    Memedi, Mevludin
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering. Örebro universitet.
    Thomas, Ilias
    Dalarna University, School of Technology and Business Studies, Statistics.
    Nyholm, Dag
    Uppsala University Hospital.
    Westin, Jerker
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Senek, Marina
    Uppsala University Hospital.
    Medvedev, Alexander
    Uppsala University.
    Askmark, Håkan
    Uppsala University.
    Aquilonius, Sten-Magnus
    Uppsala University.
    Bergquist, Filip
    University of Gothenburg.
    Constantinescu, Radu
    Ohlsson, Fredrik
    Acreo AB.
    Spira, Jack
    Sensidose AB.
    Lycke, Sara
    Cenvigo AB.
    Ericsson, Anders
    Acreo AB.
    Construction of a levodopa-response index from wearable sensorsfor quantifying Parkinson’s disease motor functions: Preliminary results2016Conference paper (Other academic)
  • 120.
    Meng, Xiangli
    Dalarna University, School of Technology and Business Studies, Statistics.
    Statistical bound of genetic solutions to quadratic assignment problems2015Report (Other academic)
    Abstract [en]

    Quadratic assignment problems (QAPs) are commonly solved by heuristic methods, where the optimum is sought iteratively. Heuristics are known to provide good solutions but the quality of the solutions, i.e., the confidence interval of the solution is unknown. This paper uses statistical optimum estimation techniques (SOETs) to assess the quality of Genetic algorithm solutions for QAPs. We examine the functioning of different SOETs regarding biasness, coverage rate and length of interval, and then we compare the SOET lower bound with deterministic ones. The commonly used deterministic bounds are confined to only a few algorithms. We show that, the Jackknife estimators have better performance than Weibull estimators, and when the number of heuristic solutions is as large as 100, higher order JK-estimators perform better than lower order ones. Compared with the deterministic bounds, the SOET lower bound performs significantly better than most deterministic lower bounds and is comparable with the best deterministic ones. 

  • 121.
    Meng, Xiangli
    Dalarna University, School of Technology and Business Studies, Statistics.
    Testing for Seasonal Unit Roots when Residuals Contain Serial Correlations under HEGY Test Framework2013Report (Other academic)
    Abstract [en]

    This paper introduces a corrected test statistic for testing seasonal unit roots when residuals contain serial correlations, based on the HEGY test proposed by Hylleberg,Engle, Granger and Yoo (1990). The serial correlations in the residuals of test regressionare accommodated by making corrections to the commonly used HEGY t statistics. Theasymptotic distributions of the corrected t statistics are free from nuisance parameters.The size and power properties of the corrected statistics for quarterly and montly data are investigated. Based on our simulations, the corrected statistics for monthly data havemore power compared with the commonly used HEGY test statistics, but they also have size distortions when there are strong negative seasonal correlations in the residuals.

  • 122.
    Meng, Xiangli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Statistics.
    How to decide upon stopping a heuristic algorithm in facility-location problems?2014In: Web Information Systems Engineering – WISE 2013 Workshops: WISE 2013 International Workshops BigWebData, MBC, PCS, STeH, QUAT, SCEH, and STSC 2013, Nanjing, China, October 13-15, 2013, Revised Selected Papers / [ed] Zhisheng Huang, Chengfei Liu, Jing He, Guangyan Huang, Berlin: Springer Berlin/Heidelberg, 2014, Vol. 8182, p. 280-283Conference paper (Refereed)
    Abstract [en]

    Solutions to combinatorial optimization, such as p-median problems of locating facilities, frequently rely on heuristics to minimize the objective function. The minimum is sought iteratively and a criterion is needed to decide when the procedure (almost) attains it. However, pre-setting the number of iterations dominates in OR applications, which implies that the quality of the solution cannot be ascertained. In this paper we compare the methods proposed previous literate of estimating minimum, and propose some thought of it.

  • 123.
    Meng, Xiangli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Information Systems. Dalarna University, School of Technology and Business Studies, Human Geography.
    Rebreyend, Pascal
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    On administrative borders and accessibility to public services:: The case of hospitals in Sweden.2014Report (Other academic)
    Abstract [en]

    An administrative border might hinder the optimal allocation of a given set of resources by restricting the flow of goods, services, and people. In this paper we address the question: Do administrative borders lead to poor accessibility to public service such as hospitals? In answering the question, we have examined the case of Sweden and its regional borders. We have used detailed data on the Swedish road network, its hospitals, and its geo-coded population. We have assessed the population’s spatial accessibility to Swedish hospitals by computing the inhabitants’ distance to the nearest hospital. We have also elaborated several scenarios ranging from strongly confining regional borders to no confinements of borders and recomputed the accessibility. Our findings imply that administrative borders are only marginally worsening the accessibility.

  • 124.
    Meng, Xiangli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    He, Changli
    Dalarna University, School of Technology and Business Studies, Statistics.
    Testing Seasonal Unit Roots in Data at Any Frequency, an HEGY approach2012Report (Other academic)
    Abstract [en]

    This paper generalizes the HEGY-type test to detect seasonal unit roots in data at any frequency, based on the seasonal unit root tests in univariate time series by Hylleberg, Engle, Granger and Yoo (1990). We introduce the seasonal unit roots at first, and then derive the mechanism of the HEGY-type test for data with any frequency. Thereafter we provide the asymptotic distributions of our test statistics when different test regressions are employed. We find that the F-statistics for testing conjugation unit roots have the same asymptotic distributions. Then we compute the finite-sample and asymptotic critical values for daily and hourly data by a Monte Carlo method. The power and size properties of our test for hourly data is investigated, and we find that including lag augmentations in auxiliary regression without lag elimination have the smallest size distortion and tests with seasonal dummies included in auxiliary regression have more power than the tests without seasonal dummies. At last we apply the our test to hourly wind power production data in Sweden and shows there are no seasonal unit roots in the series.

  • 125.
    Meng, Xiangli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Rebreyend, Pascal
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    From the road network database to a graph for localization purposes2014Report (Other academic)
    Abstract [en]

    The problems of finding best facility locations require complete and accurate road network with the corresponding population data in a specific area. However the data obtained in road network databases usually do not fit in this usage. In this paper we propose our procedure of converting the road network database to a road graph which could be used in localization problems. The road network data come from the National road data base in Sweden. The graph derived is cleaned, and reduced to a suitable level for localization problems. The population points are also processed in ordered to match with that graph. The reduction of the graph is done maintaining most of the accuracy for distance measures in the network.

  • 126.
    Meng, Xiangli
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Rebreyend, Pascal
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    On transforming a road network database to a graph for localization purpose2016In: International Journal of Web Services Research, ISSN 1545-7362, E-ISSN 1546-5004, Vol. 13, no 2, p. 46-55Article in journal (Refereed)
    Abstract [en]

    The problems of finding best facility locations require complete and accurate road networks with the corresponding population data in a specific area. However the data obtained from road network databases usually do not fit in this usage. In this paper we propose a procedure of converting the road network database to a road graph which could be used for localization problems. Several challenging problems exist in the transformation process which are commonly met also in other data bases. The procedure of dealing with those challenges are proposed. The data come from the National road data base in Sweden. The graph derived is cleaned, and reduced to a suitable level for localization problems. The residential points are also processed in ordered to match the graph. The reduction of the graph is done maintaining the accuracy of distance measures in the network.

  • 127. Mischenko, Kateryna
    et al.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Holmgren, Sverker
    Mishchenko, Vladimir
    Assessing a multiple QTL search using the variance component model2010In: Computational biology and chemistry (Print), ISSN 1476-9271, E-ISSN 1476-928X, Vol. 34, no 1, p. 34-41Article in journal (Refereed)
    Abstract [en]

    Development of variance component algorithms in genetics has previously mainly focused on animal breeding models or problems in human genetics with a simple data structure. We study alternative methods for constrained likelihood maximization in quantitative trait loci (QTL) analysis for large complex pedigrees. We apply a forward selection scheme to include several QTL and interaction effects, as well as polygenic effects, with up to five variance components in the model. We show that the implemented active set and primal-dual schemes result in accurate solutions and that they are robust. In terms of computational speed, a comparison of two approaches for approximating the Hessian of the log-likelihood shows that the method using an average information matrix is the method of choice for the five-dimensional problem. The active set method, with the average information method for Hessian computation, exhibits the fastest convergence with an average of 20 iterations per tested position, where the change in variance components <0.0001 was used as convergence criterion.

  • 128. Mishchenk, Kateryna
    et al.
    Holmgren, Sverker
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Newton-type methods for REML estimation in genetic analysis of quantitative traits.2008In: Journal of Computational Methods in Sciences and Engineering, ISSN 1875-8983, Vol. 8, no 1,2, p. 53-67Article in journal (Refereed)
  • 129. Mulder, Han A.
    et al.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Fikse, W Freddy
    Veerkamp, R F
    Strandberg, E
    Estimation of genetic variance for macro- and micro-environmental sensitivity using double hierarchical generalized linear models2013In: Genetics Selection Evolution, ISSN 0999-193X, E-ISSN 1297-9686, Vol. 45, article id 23Article in journal (Refereed)
    Abstract [en]

    Background: Genetic variation for environmental sensitivity indicates that animals are genetically different in their response to environmental factors. Environmental factors are either identifiable (e.g. temperature) and called macro-environmental or unknown and called micro-environmental. The objectives of this study were to develop a statistical method to estimate genetic parameters for macro- and micro-environmental sensitivities simultaneously, to investigate bias and precision of resulting estimates of genetic parameters and to develop and evaluate use of Akaike’s information criterion using h-likelihood to select the best fitting model.

    Methods: We assumed that genetic variation in macro- and micro-environmental sensitivities is expressed as genetic variance in the slope of a linear reaction norm and environmental variance, respectively. A reaction norm model to estimate genetic variance for macro-environmental sensitivity was combined with a structural model for residual variance to estimate genetic variance for micro-environmental sensitivity using a double hierarchical generalized linear model in ASReml. Akaike’s information criterion was constructed as model selection criterion using approximated h-likelihood. Populations of sires with large half-sib offspring groups were simulated to investigate bias and precision of estimated genetic parameters.

    Results: Designs with 100 sires, each with at least 100 offspring, are required to have standard deviations of estimated variances lower than 50% of the true value. When the number of offspring increased, standard deviations of estimates across replicates decreased substantially, especially for genetic variances of macro- and micro-environmental sensitivities. Standard deviations of estimated genetic correlations across replicates were quite large (between 0.1 and 0.4), especially when sires had few offspring. Practically, no bias was observed for estimates of any of the parameters. Using Akaike’s information criterion the true genetic model was selected as the best statistical model in at least 90% of 100 replicates when the number of offspring per sire was 100. Application of the model to lactation milk yield in dairy cattle showed that genetic variance for micro- and macro-environmental sensitivities existed.

    Conclusion: The algorithm and model selection criterion presented here can contribute to better understand genetic control of macro- and micro-environmental sensitivities. Designs or datasets should have at least 100 sires each with 100 offspring.

  • 130. Mulder, Herman A
    et al.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Veerkamp, Roel
    Prediction of breeding values for mean and environmental variance with an iterative BLUP-procedure2010In: 9th World Congress on Genetics Applied to Livestock Production. WCGALP 2010 conference., Leipzig, Germany, 2010Conference paper (Refereed)
  • 131. Nelson, Ronald M.
    et al.
    Shen, Xia
    Dalarna University, School of Technology and Business Studies, Statistics.
    Carlborg, Örjan
    qtl.outbred: Interfacing outbred line cross data with the R/qtl mapping software2011In: BMC Research Notes, ISSN 1756-0500, E-ISSN 1756-0500, Vol. 4, no 154Article in journal (Refereed)
    Abstract [en]

    Background

    qtl.outbred is an extendible interface in the statistical environment, R, for combining quantitative trait loci (QTL) mapping tools. It is built as an umbrella package that enables outbred genotype probabilities to be calculated and/or imported into the software package R/qtl.

    Findings

    Using qtl.outbred, the genotype probabilities from outbred line cross data can be calculated by interfacing with a new and efficient algorithm developed for analyzing arbitrarily large datasets (included in the package) or imported from other sources such as the web-based tool, GridQTL.

    Conclusion

    qtl.outbred will improve the speed for calculating probabilities and the ability to analyse large future datasets. This package enables the user to analyse outbred line cross data accurately, but with similar effort than inbred line cross data.

  • 132. Nelson, Ronald M
    et al.
    Temnykh, Svetlana V
    Johnson, Jennifer L
    Kharlamova, Anastasiya V
    Vladimirova, Anastasiya V
    Shepeleva, Darya V
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Trut, Lyudmila N
    Carlborg, Örjan
    Kukekova, Anna V
    Genetics of interactive behavior in silver foxes (Vulpes vulpes)2017In: Behavior Genetics, ISSN 0001-8244, E-ISSN 1573-3297, Vol. 47, no 1, p. 88-101Article in journal (Refereed)
    Abstract [en]

    Individuals involved in a social interaction exhibit different behavioral traits that, in combination, form the individual's behavioral responses. Selectively bred strains of silver foxes (Vulpes vulpes) demonstrate markedly different behaviors in their response to humans. To identify the genetic basis of these behavioral differences we constructed a large F2 population including 537 individuals by cross-breeding tame and aggressive fox strains. 98 fox behavioral traits were recorded during social interaction with a human experimenter in a standard four-step test. Patterns of fox behaviors during the test were evaluated using principal component (PC) analysis. Genetic mapping identified eight unique significant and suggestive QTL. Mapping results for the PC phenotypes from different test steps showed little overlap suggesting that different QTL are involved in regulation of behaviors exhibited in different behavioral contexts. Many individual behavioral traits mapped to the same genomic regions as PC phenotypes. This provides additional information about specific behaviors regulated by these loci. Further, three pairs of epistatic loci were also identified for PC phenotypes suggesting more complex genetic architecture of the behavioral differences between the two strains than what has previously been observed.

  • 133.
    Nelson, Ronald Michael
    et al.
    Swedish University of Agricultural Sciences.
    Nettelblad, Carl
    Uppsala University.
    Pettersson, Mats E
    Swedish University of Agricultural Sciences.
    Shen, Xia
    Swedish University of Agricultural Sciences; Uppsala University;.
    Crooks, Lucy
    Swedish University of Agricultural Sciences.
    Besnier, Francois
    Swedish University of Agricultural Sciences.
    Alvarez-Castro, José
    Swedish University of Agricultural Sciences.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Ek, Weronica
    Swedish University of Agricultural Sciences.
    Carlborg, Örjan
    Swedish University of Agricultural Sciences.
    MAPfastR: quantitative trait loci mapping in outbred line crosses2013In: G3: Genes, Genomes, Genetics, ISSN 2160-1836, E-ISSN 2160-1836, Vol. 12, no 3, p. 2147-2149Article in journal (Refereed)
    Abstract [en]

    MAPfastR is a software package developed to analyze QTL data from inbred and outbred line-crosses. The package includes a number of modules for fast and accurate QTL analyses. It has been developed in the R language for fast and comprehensive analyses of large datasets. MAPfastR is freely available at: http://www.computationalgenetics.se/?page_id=7.

  • 134.
    Rebreyend, Pascal
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Human Geography.
    How does different algorithm work when applied on the different road networks when optimal location of facilities is searched for in rural areas?2014In: Web Information Systems Engineering – WISE 2013 Workshops: WISE 2013 International Workshops BigWebData, MBC, PCS, STeH, QUAT, SCEH, and STSC 2013, Nanjing, China, October 13-15, 2013, Revised Selected Papers / [ed] Zhisheng Huang, Chengfei Liu, Jing He, Guangyan Huang, Berlin: Springer Berlin/Heidelberg, 2014, Vol. 8182, p. 284-291Conference paper (Refereed)
    Abstract [en]

    The p-median problem is often used to locate P service facilities in a geographically distributed population. Important for the performance of such a model is the distance measure. The first aim in this study is to analyze how the optimal location solutions vary, using the p-median model, when the road network is alternated. It is hard to find an exact optimal solution for p-median problems. Therefore, in this study two heuristic solutions are applied, simulating annealing and a classic heuristic. The secondary aim is to compare the optimal location solutions using different algorithms for large p-median problem. The investigation is conducted by the means of a case study in a rural region with a. asymmetrically distributed population, Dalecarlia. The study shows that the use of more accurate road networks gives better solutions for optimal location, regardless what algorithm that is used and regardless how many service facilities that is opt for. It is also shown that the Simulating annealing algorithm not just is much faster than the classic heuristic used here, but also in most cases gives better solutions.

  • 135.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics.
    Selection, Maternal Effects and Inbreeding in Reindeer Husbandry2003Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In extensive grazing systems where several owners’ flocks are allowed to mix, selection strategies will also interact, due to gene flow between flocks. The aim of the thesis was to analyse breeding schemes in terms of genetic gain and rate of inbreeding (?F), given the complexity of ownership and interaction of selection strategies within a mixing reindeer population. The data, collected between 1986 and 1997 in the reindeer herding district of Ruvhten Sijte, Sweden, comprised 12,500 records of autumn calf weights. The mean phenotypic difference in calf weights between selected and non-selected flocks was 0.67 kg after 11 years of selection in Ruvhten Sijte. The genetic difference was 0.35 kg and the realized heritability was 0.2. Based on the realized heritablility, it was shown that if all owners had applied selection, the genetic response would have been 2 kg (corresponding to an annual genetic gain of 0.4% of the phenotypic mean, including the initial lag due to age structure). The relationships between life-time patterns of female weight, calving incidence and offspring weight were examined. A female rearing a calf was shown to weigh 3.1 kg less in winter than one not rearing a calf. The regression coefficient of calf autumn weight on female weight the previous winter was 0.26. Detailed life-history patterns were obtained for females aged 1 – 15 years. The expected long-term genetic contribution method to predict genetic gain and ?F in selected populations was developed to include maternal effects. It was shown that variation in inherited maternal effects influences ?F more than does variation in non-inherited maternal effects. Furthermore, population structures affect ?F much more when there are maternal effects, than direct genetic effects alone, especially in populations with large family size. This method was used to evaluate different selection schemes in reindeer husbandry, with different proportions of a population included in each scheme. It was shown that for reindeer population sizes greater than 2,000 there is no risk of inbreeding effects.

  • 136.
    Rönnegård, Lars
    Dalarna University, School of Technology and Business Studies, Statistics. Swedish University of Agricultural Sciences.
    The evolution of peer-reviewed papers.2019In: Journal of Animal Breeding and Genetics, ISSN 0931-2668, E-ISSN 1439-0388, Vol. 136, no 2, p. 77-78Article in journal (Other academic)
  • 137.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Al-Sarraj, Razaw
    von Rosen, Dietrich
    Non-iterative variance component estimation in QTL analysis.2009In: Journal of Animal Breeding and Genetics, ISSN 0931-2668, E-ISSN 1439-0388, Vol. 126, no 1, p. 110-116Article in journal (Refereed)
    Abstract [en]

    In variance component quantitative trait loci (QTL) analysis, a mixed model is used to detect the most likely chromosome position of a QTL. The putative QTL is included as a random effect and a method is needed to estimate the QTL variance. The standard estimation method used is an iterative method based on the restricted maximum likelihood (REML). In this paper, we present a novel non-iterative variance component estimation method. This method is based on Henderson's method 3, but relaxes the condition of unbiasedness. Two similar estimators were compared, which were developed from two different partitions of the sum of squares in Henderson's method 3. The approach was compared with REML on data from a European wild boar × domestic pig intercross. A meat quality trait was studied on chromosome 6 where a functional gene was known to be located. Both partitions resulted in estimated QTL variances close to the REML estimates. From the non-iterative estimates, we could also compute good approximations of the likelihood ratio curve on the studied chromosome.

  • 138.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Besnier, Francois
    Carlborg, Örjan
    An improved method for QTL detection and identification of within-line segregation in F2 intercross designs2008In: Genetics, ISSN 0016-6731, E-ISSN 1943-2631, Vol. 178, no April, p. 2315-2326Article in journal (Refereed)
  • 139.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Besnier, Francois
    Carlborg, Örjan
    Modelling dominance in a flexible intercross analysis2009In: BMC Genetics, ISSN 1471-2156, E-ISSN 1471-2156, Vol. 10, article id 30Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to develop a flexible model for analysis of quantitative trait loci (QTL) in outbred line crosses, which includes both additive and dominance effects. Our flexible intercross analysis (FIA) model accounts for QTL that are not fixed within founder lines and is based on the variance component framework. Genome scans with FIA are performed using a score statistic, which does not require variance component estimation.

    RESULTS: Simulations of a pedigree with 800 F2 individuals showed that the power of FIA including both additive and dominance effects was almost 50% for a QTL with equal allele frequencies in both lines with complete dominance and a moderate effect, whereas the power of a traditional regression model was equal to the chosen significance value of 5%. The power of FIA without dominance effects included in the model was close to those obtained for FIA with dominance for all simulated cases except for QTL with overdominant effects. A genome-wide linkage analysis of experimental data from an F2 intercross between Red Jungle Fowl and White Leghorn was performed with both additive and dominance effects included in FIA. The score values for chicken body weight at 200 days of age were similar to those obtained in FIA analysis without dominance.

    CONCLUSION: We have extended FIA to include QTL dominance effects. The power of FIA was superior, or similar, to standard regression methods for QTL effects with dominance. The difference in power for FIA with or without dominance is expected to be small as long as the QTL effects are not overdominant. We suggest that FIA with only additive effects should be the standard model to be used, especially since it is more computationally efficient.

  • 140.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Carlborg, Ö.
    A new efficient method for QTL mapping in divergent intercrosses incorporating within line variation2006In: 8th World Congress on Genetics Applied to Livestock Production, Brazil, 2006Conference paper (Other academic)
  • 141.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Carlborg, Örjan
    Separation of base allele and sampling term effects gives new insights in variance component QTL analysis2007In: BMC Genetics, ISSN 1471-2156, E-ISSN 1471-2156, Vol. 8, no 1Article in journal (Refereed)
    Abstract [en]

    Background Variance component (VC) models are commonly used for Quantitative Trait Loci (QTL) mapping in outbred populations. Here, the QTL effect is given as a random effect and a critical part of the model is the relationship between the phenotypic values and the random effect. In the traditional VC model, each individual has a unique QTL effect and the relationship between these random effects is given as a covariance structure (known as the identity-by-descent (IBD) matrix). Results We present an alternative notation of the variance component model, where the elements of the random effect are independent base generation allele effects and sampling term effects. The relationship between the phenotypic vales and the random effect is given by an incidence matrix, which results in a novel, but statistically equivalent, version of the traditional VC model. A general algorithm to estimate this incidence matrix is presented. Since the model is given in terms of base generation allele effects and sampling term effects, these effects can be estimated separately using best linear unbiased prediction (BLUP). From simulated data, we showed that biallelic QTL effects could be accurately clustered using the BLUP obtained from our model notation when markers are fully informative, and that the accuracy increased with the size of the QTL effect. We also developed a measure indicating whether a base generation marker homozygote is a QTL heterozygote or not, by comparing the variances of the sampling term BLUP and the base generation allele BLUP. A ratio greater than one gives strong support for a QTL heterozygote. Conclusion We developed a simple presentation of the VC QTL model for identification of base generation allele effects in QTL linkage analysis. The base generation allele effects and sampling term effects were separated in our model notation. This clarifies the assumptions of the model and should also enhance the development of genome scan methods.

  • 142.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Danell, Ö
    Genetic response to selection on reindeer calf weights.2003In: Rangifer, ISSN 1890-6729, Vol. 23, no 1, p. 1-13Article in journal (Refereed)
  • 143.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Danell, Ö.
    Hjordstrukturering och urval vid slakt2002In: Boazudiehtu - Nyhetsblad om forskning och utveckling i renskötseln, no 3Article in journal (Other academic)
  • 144.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Danell, Öje
    Gene flow and potential selection response in age-structured subpopulations having a common male pool.2001In: Animal Science, ISSN 0261-698X, Vol. 72, no 3, p. 427-440Article in journal (Refereed)
  • 145.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Felleki, Majbritt
    Dalarna University, School of Technology and Business Studies, Statistics.
    Fikse, Freddy
    Mulder, Herman A.
    Strandberg, Erling
    Genetic heterogeneity of residual variance: estimation of variance components using double hierarchical generalized linear models2010In: Genetics Selection Evolution, ISSN 0999-193X, E-ISSN 1297-9686, Vol. 42, article id 8Article in journal (Refereed)
    Abstract [en]

    Background: The sensitivity to microenvironmental changes varies among animals and may be under genetic control. It is essential to take this element into account when aiming at breeding robust farm animals. Here, linear mixed models with genetic effects in the residual variance part of the model can be used. Such models have previously been fitted using EM and MCMC algorithms.

    Results: We propose the use of double hierarchical generalized linear models (DHGLM), where the squared residuals are assumed to be gamma distributed and the residual variance is fitted using a generalized linear model. The algorithm iterates between two sets of mixed model equations, one on the level of observations and one on the level of variances. The method was validated using simulations and also by re-analyzing a data set on pig litter size that was previously analyzed using a Bayesian approach. The pig litter size data contained 10,060 records from 4,149 sows. The DHGLM was implemented using the ASReml software and the algorithm converged within three minutes on a Linux server. The estimates were similar to those previously obtained using Bayesian methodology, especially the variance components in the residual variance part of the model.

    Conclusions: We have shown that variance components in the residual variance part of a linear mixed model can be estimated using a DHGLM approach. The method enables analyses of animal models with large numbers of observations. An important future development of the DHGLM methodology is to include the genetic correlation between the random effects in the mean and residual variance parts of the model as a parameter of the DHGLM.

  • 146.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics. Swedish Univ Agr Sci, Dept Anim Breeding & Genet, S-75007 Uppsala, Sweden.
    Felleki, Majbritt
    Dalarna University, School of Technology and Business Studies, Statistics. Swedish Univ Agr Sci, Dept Anim Breeding & Genet, S-75007 Uppsala, Sweden.
    Fikse, W. F.
    Mulder, H. A.
    Strandberg, E.
    Variance component and breeding value estimation for genetic heterogeneity of residual variance in Swedish Holstein dairy cattle2013In: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 96, no 4, p. 2627-2636Article in journal (Refereed)
    Abstract [en]

    Trait uniformity, or micro-environmental sensitivity, may be studied through individual differences in residual variance. These differences appear to be heritable, and the need exists, therefore, to fit models to predict breeding values explaining differences in residual variance. The aim of this paper is to estimate breeding values for micro-environmental sensitivity (vEBV) in milk yield and somatic cell score, and their associated variance components, on a large dairy cattle data set having more than 1.6 million records. Estimation of variance components, ordinary breeding values, and vEBV was performed using standard variance component estimation software (ASReml), applying the methodology for double hierarchical generalized linear models. Estimation using ASReml took less than 7 d on a Linux server. The genetic standard deviations for residual variance were 0.21 and 0.22 for somatic cell score and milk yield, respectively, which indicate moderate genetic variance for residual variance and imply that a standard deviation change in vEBV for one of these traits would alter the residual variance by 20%. This study shows that estimation of variance components, estimated breeding values and vEBV, is feasible for large dairy cattle data sets using standard variance component estimation software. The possibility to select for uniformity in Holstein dairy cattle based on these estimates is discussed.

  • 147.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Fikse, Freddy
    Mulder, Herman
    Strandberg, E
    Breeding Value Estimation for Environmental Sensitivity on a Large Dairy Cattle Data Set2011In: Interbull Meeting, Stavanger, Norway, 2011Conference paper (Other academic)
    Abstract [en]

    Animal robustness, or environmental sensitivity, may be studied through individual differences in re-sidual variance. These differences appear to be heritable, and there is therefore a need to fit models having breeding values explaining differences in residual variance. The aim of this report is to study whether breeding value estimation for environmental sensitivity (vEBV) can be performed on a large dairy cattle data set having around 1.6 million records. Two traits were analyzed separately, somatic cell score and milk yield. Estimation of variance components, ordinary breeding values and vEBVs was performed using standard variance component estimation software (ASReml), applying the me-thodology for double hierarchical generalized linear models. Converged estimates were obtained by running ASReml iteratively 20 times, which took less than 10 days on a Linux server. The genetic coefficients of variation for environmental variance were 0.45 and 0.52, for somatic cell score and milk yield, respectively, which indicate a substantial genetic variance for environmental variance. This study shows that estimation of variance components, EBVs and vEBVs, is feasible for large dairy cattle data sets using standard variance component estimation software.

  • 148.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Forslund, Pär
    Danell, Öje
    Lifetime patterns in adult female mass, reproduction and offspring mass in semidomesticated reindeer (Rangifer tarandus tarandus).2002In: Canadian Journal of Zoology, ISSN 0008-4301, E-ISSN 1480-3283, Vol. 80, no 12, p. 2047-2055Article in journal (Refereed)
  • 149.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Hannu, U
    Urval ökar renhjordens produktivitet.2003In: Boazudiehtu - Nyhetsblad om forskning och utveckling i renskötseln, no 1Article in journal (Other academic)
  • 150.
    Rönnegård, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics. Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Lee, Y
    Seoul National University, Seoul, Korea.
    Exploring the potential of hierarchical generalized linear models in animal breeding and genetics2013In: Journal of Animal Breeding and Genetics, ISSN 0931-2668, E-ISSN 1439-0388, Vol. 130, no 6, p. 415-416Article in journal (Refereed)
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