| 1. |
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| 2. |
- Carling, Kenneth, et al.
(författare)
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Methodological issues in applying Location Models to Rural areas
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Location Models are usedfor planning the location of multiple service centers in order to serve a geographicallydistributed population. A cornerstone of such models is the measure of distancebetween the service center and a set of demand points, viz, the location of thepopulation (customers, pupils, patients and so on). Theoretical as well asempirical evidence support the current practice of using the Euclidian distancein metropolitan areas. In this paper, we argue and provide empirical evidencethat such a measure is misleading once the Location Models are applied to ruralareas with heterogeneous transport networks. This paper stems from the problemof finding an optimal allocation of a pre-specified number of hospitals in alarge Swedish region with a low population density. We conclude that the Euclidianand the network distances based on a homogenous network (equal travel costs inthe whole network) give approximately the same optimums. However networkdistances calculated from a heterogeneous network (different travel costs indifferent parts of the network) give widely different optimums when the numberof hospitals increases. In terms ofaccessibility we find that the recent closure of hospitals and the in-optimallocation of the remaining ones has increased the average travel distance by 75%for the population. Finally, aggregation the population misplaces the hospitalsby on average 10 km.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Alam, Moudud, et al.
(författare)
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Fitting spatial models in the R package: hglm
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present a new version of the hglm package for fittinghierarchical generalized linear models (HGLM) with spatially correlated random effects. A CAR family for conditional autoregressive random effects was implemented. Eigen decomposition of the matrix describing the spatial structure (e.g. the neighborhood matrix) was used to transform the CAR random effectsinto an independent, but heteroscedastic, gaussian random effect. A linear predictor is fitted for the random effect variance to estimate the parameters in the CAR model.This gives a computationally efficient algorithm for moderately sized problems (e.g. n<5000).
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| 7. |
- Alam, Moudud, et al.
(författare)
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High-School Students´ Summer Jobs and their Ensuing Labor Market Achievement : the Long Term Effect
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In part because of high and persistent youth unemployment, adolescent students’ transition from school to work is an important policy and research topic. Many countries have implemented public programs offering summer jobs or work while in high-school as measures to smooth the transition. While the immediate effect of the programs on school attendance, school grades, and disposable income is well documented, their effect on the transition to the labor market remains an open question. Observational studies have shown strong positive effects of summer jobs, but also that the estimated effect is highly vulnerable to selection bias. In this paper, some 3700 high-school students applying for summer jobs in the period 1995-2003,via a program, are followed to 30 years of age. A quarter of the applicants were randomly offered a summer job each year. Among the remaining students, 50% had a (non-program related) summer job while in high-school. We find the income, post high-school, for the offered and non-offered groups to be similar and conclude that the effect of summer jobs on the transition to the labor market is inconsequential.
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| 8. |
- Alam, Moudud, et al.
(författare)
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Likelihood estimate of treatment effects under selection bias
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We consider methods for estimating causal effects of treatment in the situation where the individuals in the treatment and the control group are self selected, i.e., the selection mechanism is not randomized. In this case, simple comparison of treated and control outcomes will not generally yield valid estimates of casual effects. The propensity score method is frequently used for the evaluation of treatment effect. However, this method is based onsome strong assumptions, which are not directly testable. In this paper, we present an alternative modeling approachto draw causal inference by using share random-effect model and the computational algorithm to draw likelihood based inference with such a model. With small numerical studies and a real data analysis, we show that our approach gives not only more efficient estimates but it is also less sensitive to model misspecifications, which we consider, than the existing methods.
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| 9. |
- Alam, Moudud, et al.
(författare)
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The program and treatment effect of summer jobs on girls’ post-schooling incomes
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Public programs (of disputed effect) offering summer jobs or work while in high school to smooth the transition from school to work is commonplace. In this paper, 1447 girls in their first grade of high school between 1997-2003 and randomly allotted summer jobs via a program in Falun (Sweden) are followed 5-12 years after graduation. The program led to a substantially larger accumulation of income while in high school. The causal effect of the high school income on post-schooling incomes was substantial and statistically significant. The implied elasticity of 0.4 is however potentially inflated dueto heterogeneous effects.
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| 10. |
- Alam, Moudud, et al.
(författare)
-
Utvärdering av det arbetsmarknadspolitiska projektet "Volvo Cars och dess underleverantörer"
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport är en utvärdering av det arbetsmarknadspolitiska projektet "Volvo Cars och dess underleverantörer", som har genomförts av Arbetsförmedlingen i samarbete med Skolverket och Svenska ESF-rådet. Den 5 juni 2009 ansökte Sveriges regering om medel hos den Europeiska globaliseringsfonen (EGF)2 för att kunna erbjuda åtgärder för personer som blivit uppsagda från Volvo Cars AB och dess underleverantörer. Syftet med projektet var att kunna erbjuda de som blivit uppsagda kompetensutveckling, nya yrkeskunskaper och möjlighet att etablera egna företag.På operativ nivå drevs projektet i samverkan mellan Arbetsförmedlingen och den kom-munala yrkesvuxenutbildningen ("Yrkesvux"). Yrkesvux i Göteborgs kommun fick i upp-drag av Skolverket att samordna den del av verksamheten som berörde kommunal yr-kesvuxenutbildning. Projektet startade 1 januari 2010 och avslutades 31 maj 2011. Enligt kommissionens beslut fick medel även användas retroaktivt för insatser som hade givits till de uppsagda i form av olika arbetsmarknadsutbildningar, det s.k. snabbspåret, under 2009 innan projektet hade startat.Av nästan 5 000 individer i målgruppen som registrerade sig vid Arbetsförmedlingen del-tog knappt en fjärdedel i projektets insatser (exkl. vägledning). Av dessa gick 55 procent i aktiviteter enbart genom Arbetsförmedlingen, 37 procent enbart genom Yrkesvux och åtta procent genom både Arbetsförmedlingen och Yrkesvux. De vanligaste förekommande utbildningsinriktningarna var industri och bygg, fordonsindustri, transport och magasine-ring, omvårdnad och handel.
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| 11. |
- Andersson, Ing-Marie, et al.
(författare)
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Arbetsmiljö vid service- och reparation av skogsbränslemaskiner
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna studie är att ta fram underlag till en arbetsmiljöchecklista för service och reparationsarbete av skogsbränslemaskiner. Däri ingår maskiner för skördning, transport och sönderdelning av sortimenten GROT (grenar och toppar), stubbar respektive klenskog. En avgränsning har gjorts till service och reparationsarbete som görs ute i fält. Tjugotre riktade fallstudier har genomförts i Mellansverige med fokus på service- och reparationsarbete som skett ute i fält. Arbetsmiljöfaktorer har observerats och dokumenterats med foto, samtal har förts med förare och servicemän, och mätningar av buller och damm har genomförts. Vid samtal med förare har efterfrågats hur ofta service och reparationsarbete genomförs, vem som gör det, vilka moment som ingår samt var det vanligtvis utförs. Servicearbete ingår i förarens arbetsuppgifter och förekommer med olika intervall. Vissa arbetsmoment utförs dagligen, såsom byte av huggstål, smörjning av krannipplar och renblåsning av container. Andra sker med längre intervall, såsom byte av oljor och filter. I studien har tillvägagångssätt och arbetsmiljörisker vid omfattande, respektive mindre, service- ochreparationsarbete identifierats. Service- och reparationsarbete är ofta tungt och smutsigt.Arbetsmiljörisker samt goda exempel på lösningar för olika typer av maskiner har sammanställts.Baserat på studiens empiriska resultat, genomförda litteraturstudier och analyser harcheckpunkter som bör ingå i en arbetsmiljöchecklista identifierats. Identifierade checkpunkternahar grupperats utifrån målgrupp och typ av arbetsmoment med syftet att vara praktisktanvändbara. Målgrupperna är maskintillverkare/ägare som modifierar maskiner, respektiveservicemän och förare. Framtagna checkpunkter utgör en grund till en checklista för arbete medservice- och reparationsarbete av skogsbränslemaskiner.
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| 12. |
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| 13. |
- Boluk, Karla, et al.
(författare)
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Exploring the discourses used to sell heritage in Sweden
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Heritage tourism is a form of niche tourism which has emerged as an alternative to mass tourism. However the discourses used to market some heritage products generally appeal to an elite group in society who are demanding. Thus heritage tourism is marketed and packaged in a way to appeal to an exclusive group who are interested in tailor-made products that provide some entertainment value. The aim of this paper is to investigate the marketing strategies and goals for tourism development, from the perspective of two World Heritage Sites (WHS) in Sweden including the Great Copper Mountain in Falun and the Old Church Town in Luleå. Accordingly, the discourses used to sell heritage in the context of Sweden are discussed. A mixed-methods approach was used by the authors to carry out this investigation. The results of the analysis revealed that the heritage presented in the two cases are marketed as exclusive and as such, preclude the participation of some individuals. Furthermore, it was established that enhanced communication between WHS products and Sweden and other tourism products would improve visitation.
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| 14. |
- Bornhäll, Anders, 1984-, et al.
(författare)
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Employment Protection Legislation and Firm Growth : Evidence from a Natural Experiment
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A natural experiment is used to identify the causal relationship between employment protection legislation and fi…rm growth. The natural experiment occurred in Sweden in 2001, when an exemption made it possible for fi…rms with less than eleven employees to exclude two workers from the last-in-fi…rst-out principle when dismissing personnel. The estimated average treatment effect of the reform show that the number of employees increased with 0.135 percent in fi…rms with 5-9 employees relative to fi…rms with 10-15 employees, which corresponds to over 5,000 additional jobs per year created by the reform. Firms with ten employees, just below the size threshold, became 3.4 percent less likely to increase their workforce to a level surpassing the threshold, indicating that the last-in-…first-out rule prevented these …firms from growing. Thus, employment protection legislation seems to act as a growth barrier for small fi…rms.
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| 15. |
- Bornhäll, Anders, 1984-, et al.
(författare)
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The unseen job creators : Growth potential among non-growing …firms
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Among 104,231 limited liability fi…rms in Sweden with at least two employees during 1997-2010, almost 10 % did not hire new employees in any given 3-year period despite having high profi…ts. Nearly half of these …firms continued to have high or medium pro…fits in the next three-year period, but still no growth. Regression analysis indicates that these fi…rms were not randomly distributed; rather they were small and young, did not belong to an enterprise group, and operated in local markets with high profi…t-opportunities. We conclude that it might be more benefi…cial to focus policy towards these …firms instead of towards a few high-growth fi…rms that, having just grown exponentially, may not be best positioned to grow further.
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| 16. |
- Carling, Kenneth, 1967-
(författare)
-
A comment on outlier detection and skewed distributions
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- It seems that a paper of mine appearing in Computational Statistics & Data Analysis (Carling, 2000) has prompted the development of outlier detection methods for highly skewed data. However, I wrote the paper in the spirit of Exploratory Data Analysis (Tukey, 1977) and I shared Tukey’s opinion, and I still hold it, that skewed data are better to be transformed for approximate symmetry prior to detection of outliers (or other data analyses).
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| 17. |
- Carling, Kenneth, et al.
(författare)
-
Confidence in heuristic solutions?
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Solutions to combinatorial optimization problems frequently rely on heuristics to minimize an objective function. The optimum is sought iteratively and pre-setting the number of iterations dominates in operations research applications, which implies that the quality of the solution cannot be ascertained. Deterministic bounds offer a mean of ascertaining the quality, but such bounds are available for only a limited number of heuristics and the length of the interval may be difficult to control in an application. A small, almost dormant, branch of the literature suggests using statistical principles to derive statistical bounds for the optimum. We discuss alternative approaches to derive statistical bounds. We also assess their performance by testing them on 40 test p-median problems on facility location, taken from Beasley’s OR-library, for which the optimum is known. We consider three popular heuristics for solving such location problems; simulated annealing, vertex substitution, and Lagrangian relaxation where only the last offers deterministic bounds. Moreover, we illustrate statistical bounds in the location of 71 regional delivery points of the Swedish Post. We find statistical bounds reliable and much more efficient than deterministic bounds provided that the heuristic solutions are sampled close to the optimum. Statistical bounds are also found computationally affordable.
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| 18. |
- Carling, Kenneth, et al.
(författare)
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GRASP and statistical bounds for heuristic solutions to combinatorial problems
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The quality of a heuristic solution to a NP-hard combinatorial problem is hard to assess. A few studies have advocated and tested statistical bounds as a method for assessment. These studies indicate that statistical bounds are superior to the more widely known and used deterministic bounds. However, the previous studies have been limited to a few metaheuristics and combinatorial problems and, hence, the general performance of statistical bounds in combinatorial optimization remains an open question. This work complements the existing literature on statistical bounds by testing them on the metaheuristic Greedy Randomized Adaptive Search Procedures (GRASP) and four combinatorial problems. Our findings confirm previous results that statistical bounds are reliable for the p-median problem, while we note that they also seem reliable for the set covering problem. For the quadratic assignment problem, the statistical bounds has previously been found reliable when obtained from the Genetic algorithm whereas in this work they found less reliable. Finally, we provide statistical bounds to four 2-path network design problem instances for which the optimum is currently unknown.
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| 19. |
- Carling, Kenneth, et al.
(författare)
-
Measuring CO2 emissions induced by online and brick-and-mortar retailing
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We develop a method for empirically measuring the difference in carbon footprint between traditional and online retailing (“e-tailing”) from entry point to a geographical area to consumer residence. The method only requires data on the locations of brick-and-mortar stores, online delivery points, and residences of the region’s population, and on the goods transportation networks in the studied region. Such data are readily available in most countries, so the method is not country or region specific. The method has been evaluated using data from the Dalecarlia region in Sweden, and is shown to be robust to all assumptions made. In our empirical example, the results indicate that the average distance from consumer residence to a brick-and-mortar retailer is 48.54 km in the studied region, while the average distance to an online delivery point is 6.7 km. The results also indicate that e-tailing increases the average distance traveled from the regional entry point to the delivery point from 47.15 km for a brick-and-mortar store to 122.75 km for the online delivery points. However, as professional carriers transport the products in bulk to stores or online delivery points, which is more efficient than consumers’ transporting the products to their residences, the results indicate that consumers switching from traditional to e-tailing on average reduce their CO2 footprints by 84% when buying standard consumer electronics products.
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| 20. |
- Carling, Kenneth, et al.
(författare)
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Short Communication: A compelling argument for the gravity p-median model
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The p-median model is used to locate P facilities to serve a geographically distributed population. Conventionally, it is assumed that the population always travels to the nearest facility. Drezner and Drezner (2006, 2007) provide three arguments on why this assumption might be incorrect, and they introduce the extended the gravity p-median model to relax the assumption. We favour the gravity p-median model, but we note that in an applied setting, Drezner and Drezner’s arguments are incomplete. In this communication, we point at the existence of a fourth compelling argument for the gravity p-median model.
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| 21. |
- Carling, Kenneth, et al.
(författare)
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The effects of taxing truck distance on CO2 emissions from transports in retailing
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- To finance transportation infrastructure and to address social and environmental negative externalities of road transports, several countries have recently introduced or consider a distance based tax on trucks. In the competitive retail market such tax can be expected to lower the demand and thereby reduce CO2 emissions of road transports. However, as we show in this paper, such tax might also slow down the transition towards e-tailing. Considering that previous research indicates that a consumer switching from brick-and-mortar shopping to e-tailing reduces her CO2 emissions substantially, the direction and magnitude of the environmental net effect of the tax is unclear. In this paper, we assess the net effect in a Swedish regional retail market where the tax not yet is in place. We predict the net effect on CO2 emissions to be positive, but off-set by about 50% because of a slower transition to e-tailing.
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| 22. |
- Carling, Kenneth, 1967-
(författare)
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The emergence of Microdata Analysis and its intellectual history over the past two decades
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- By 2020, students of Dalarna University had produced some 100 Bachelor and Master’s theses and 25 Licentiate or Doctoral theses in the academic discipline of Microdata Analysis guided by the university’s faculty. While firmly rooted in the tradition and the format of the formal sciences Computer Science and Mathematics, the theses are disparate with regard to area of investigation, research method, and epistemology. The research carried out in these theses is recognized internationally by learned societies and their journals and conferences, yet Dalarna University remains globally unique in labelling an academic discipline Microdata Analysis. This paper attempts to narrate the history of the forming process of Microdata Analysis at the university and grasp its nature.
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| 23. |
- Cialani, Catia
(författare)
-
CO2 Emissions, GDP and trade : a panel cointegration approach
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper examines the relationships among per capita CO2 emissions, per capita GDP and international trade based on panel data sets spanning the period 1960-2008: one for 150 countries and the others for sub-samples comprising OECD and Non-OECD economies. We apply panel unit root and cointegration tests, and estimate a panel error correction model. The results from the error correction model suggest that there are long-term relationships between the variables for the whole sample and for Non-OECD countries. Finally, Granger causality tests show that there is bi-directional short-term causality between per capita GDP and international trade for the whole sample and between per capita GDP and CO2 emissions for OECD countries
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| 24. |
- Cialani, Catia
(författare)
-
Growth and Inequality : A study of Swedish municipalities
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper explores the relationship between the growth rate of the average income and income inequality using data at the municipal level in Sweden for the period 1992-2007. We estimate a fixed effects panel data growth model where the within-municipality income inequality is one of the explanatory variables. Different inequality measures (Gini coefficient, top income shares, and measures of inequality in the lower and upper ends of the income distribution) are also examined. We find a positive and significant relationship between income growth and income inequality, measured as the Gini coefficient and top income shares, respectively. In addition, while inequality at the upper end of the income distribution is positively associated with the income growth rate, inequality at the lower end of the income distribution seems to be negatively related to the growth rate. Our findings also suggest that increased income inequality enhances growth more in municipalities with a high level of average income than in those with a low level of average income.
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| 25. |
- Cialani, Catia, et al.
(författare)
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Growth, migration and unemployment across Swedish municipalities
- 2013
-
Rapport (populärvet., debatt m.m.)abstract
- Fundamental questions in economics are why some regions are richer than others, why their economic growth rates vary, whether their growth tends to converge and the key factors that contribute to the variations. These questions have not yet been fully addressed, but changes in the local tax base are clearly influenced by the average income growth rate, net migration rate, and changes in unemployment rates. Thus, the main aim of this paper is to explore in depth the interactive effects of these factors (and local policy variables) in Swedish municipalities, by estimating a proposed three-equation system. Our main finding is that increases in local public expenditures and income taxes have negative effects on subsequent local income growth. In addition, our results support the conditional convergence hypothesis, i.e. that average income tends to grow more rapidly in relatively poor local jurisdictions than in initially “richer” jurisdictions, conditional on the other explanatory variables.
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| 26. |
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| 27. |
- Fleyeh, Hasan, et al.
(författare)
-
Benchmark Evaluation of HOG Descriptors as Features for Classification of Traffic Signs
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this paper is to analyze the performance of the Histograms of Oriented Gradients (HOG) as descriptors for traffic signs recognition. The test dataset consists of speed limit traffic signs because of their high inter-class similarities. HOG features of speed limit signs, which were extracted from different traffic scenes, were computed and a Gentle AdaBoost classifier was invoked to evaluate the different features. The performance of HOG was tested with a dataset consisting of 1727 Swedish speed signs images. Different numbers of HOG features per descriptor, ranging from 36 features up 396 features, were computed for each traffic sign in the benchmark testing. The results show that HOG features perform high classification rate as the Gentle AdaBoost classification rate was 99.42%, and they are suitable to real time traffic sign recognition. However, it is found that changing the number of orientation bins has insignificant effect on the classification rate. In addition to this, HOG descriptors are not robust with respect to sign orientation.
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| 28. |
- Fleyeh, Hasan
(författare)
-
Traffic sign recognition without color information
- 2015
-
Ingår i: Colour and Visual Computing Symposium (CVCS), 2015. - Borlänge : Högskolan Dalarna. ; , s. 1-6
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Color represents an important attribute in the field of traffic sign recognition. However, when the color of the traffic sign fades or the traffic scene is collected in gray as in the case of Infrared imaging, then color based recognition systems fail. Other problems related to color are simply that different countries use different colors. Even within the European Union, colors of traffic signs are not the same.This paper aims to present a new approach to detect traffic signs without color attributes. It is based a two-stage sliding window which detects traffic signs in the multi-scale image. Histogram of Oriented Gradients (HOG) descriptors are computed as a quality function which are evaluated by two SVM classifier; the coarse and the fine detectors. Different objects detected by the coarse detectors are clustered and a fine search is conducted in the areas where traffic signs are more probable to exist. Experiments conducted to detect traffic signs under different light conditions such as sunny, cloudy, fog and snow fall have showed a performance of 98% and very low false positive rate. The proposed approach was tested on the Yield traffic signs because it has a simple triangular shape which can be found in many places other than the traffic signs and represent a challenge to the proposed approach.
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| 29. |
- Han, Mengjie, et al.
(författare)
-
A review of reinforcement learning methodologies on control systems for building energy
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The usage of energy directly leads to a great amount of consumption of the non-renewable fossil resources. Exploiting fossil resources energy can influence both climate and health via ineluctable emissions. Raising awareness, choosing alternative energy and developing energy efficient equipment contributes to reducing the demand for fossil resources energy, but the implementation of them usually takes a long time. Since building energy amounts to around one-third of global energy consumption, and systems in buildings, e.g. HVAC, can be intervened by individual building management, advanced and reliable control techniques for buildings are expected to have a substantial contribution to reducing global energy consumptions. Among those control techniques, the model-free, data-driven reinforcement learning method seems distinctive and applicable. The success of the reinforcement learning method in many artificial intelligence applications has brought us an explicit indication of implementing the method on building energy control. Fruitful algorithms complement each other and guarantee the quality of the optimisation. As a central brain of smart building automation systems, the control technique directly affects the performance of buildings. However, the examination of previous works based on reinforcement learning methodologies are not available and, moreover, how the algorithms can be developed is still vague. Therefore, this paper briefly analyses the empirical applications from the methodology point of view and proposes the future research direction.
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| 30. |
- Han, Mengjie, et al.
(författare)
-
How do different densities in a network affect the optimal location of service centers?
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The p-median problem is often used to locate p service centers by minimizing their distances to a geographically distributed demand (n). The optimal locations are sensitive to geographical context such as road network and demand points especially when they are asymmetrically distributed in the plane. Most studies focus on evaluating performances of the p-median model when p and n vary. To our knowledge this is not a very well-studied problem when the road network is alternated especially when it is applied in a real world context. The aim in this study is to analyze how the optimal location solutions vary, using the p-median model, when the density in the road network is alternated. The investigation is conducted by the means of a case study in a region in Sweden with an asymmetrically distributed population (15,000 weighted demand points), Dalecarlia. To locate 5 to 50 service centers we use the national transport administrations official road network (NVDB). The road network consists of 1.5 million nodes. To find the optimal location we start with 500 candidate nodes in the network and increase the number of candidate nodes in steps up to 67,000. To find the optimal solution we use a simulated annealing algorithm with adaptive tuning of the temperature. The results show that there is a limited improvement in the optimal solutions when nodes in the road network increase and p is low. When p is high the improvements are larger. The results also show that choice of the best network depends on p. The larger p the larger density of the network is needed.
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| 31. |
- Han, Mengjie, et al.
(författare)
-
How do neighbouring populations affect local population change over time?
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study covers a period when society changed from a pre-industrial agricultural society to a post-industrial service-producing society. Parallel with this social transformation, major population changes took place. In this study, we analyse how local population changes are affected by neighbouring populations. To do so we use the last 200 years of local population change that redistributed population in Sweden. We use literature to identify several different processes and spatial dependencies in the redistribution between a parish and its surrounding parishes. The analysis is based on a unique unchanged historical parish division, and we use an index of local spatial correlation to describe different kinds of spatial dependencies that have influenced the redistribution of the population. To control inherent time dependencies, we introduce a non-separable spatial temporal correlation model into the analysis of population redistribution. Hereby, several different spatial dependencies can be observed simultaneously over time. The main conclusions are that while local population changes have been highly dependent on the neighbouring populations in the 19th century, this spatial dependence have become insignificant already when two parishes is separated by 5 kilometres in the late 20th century. Another conclusion is that the time dependency in the population change is higher when the population redistribution is weak, as it currently is and as it was during the 19th century until the start of industrial revolution.
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| 32. |
- Han, Mengjie, et al.
(författare)
-
How does data quality in a network affect heuristic solutions?
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- To have good data quality with high complexity is often seen to be important. Intuition says that the higher accuracy and complexity the data have the better the analytic solutions becomes if it is possible to handle the increasing computing time. However, for most of the practical computational problems, high complexity data means that computational times become too long or that heuristics used to solve the problem have difficulties to reach good solutions. This is even further stressed when the size of the combinatorial problem increases. Consequently, we often need a simplified data to deal with complex combinatorial problems. In this study we stress the question of how the complexity and accuracy in a network affect the quality of the heuristic solutions for different sizes of the combinatorial problem. We evaluate this question by applying the commonly usedp-median model, which is used to find optimal locations in a network of p supply points that serve n demand points. To evaluate this, we vary both the accuracy (the number of nodes) of the network and the size of the combinatorial problem (p).The investigation is conducted by the means of a case study in a region in Sweden with an asymmetrically distributed population (15,000 weighted demand points), Dalecarlia. To locate 5 to 50 supply points we use the national transport administrations official road network (NVDB). The road network consists of 1.5 million nodes. To find the optimal location we start with 500 candidate nodes in the network and increase the number of candidate nodes in steps up to 67,000 (which is aggregated from the 1.5 million nodes). To find the optimal solution we use a simulated annealing algorithm with adaptive tuning of the temperature. The results show that there is a limitedimprovement in the optimal solutions when the accuracy in the road network increase and the combinatorial problem (lowp) is simple. When the combinatorial problem is complex (large p) the improvements of increasing the accuracy in the road network are much larger. The results also show that choice of the best accuracy of the network depends on the complexity of the combinatorial (varying p) problem.
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| 33. |
- Han, Mengjie, et al.
(författare)
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How does the use of different road networks effect the optimal location of facilities in rural areas?
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.Distance measure can vary if the accuracy of the road network varies. The rst 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 nd 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 dierent algorithms for large p-median problem. The investigation is conducted by the means of a case study in a rural region with an 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 optimized for. It is also shown that the simulated annealing algorithm not just is much faster than the classic heuristic used here, but also in most cases gives better location solutions.
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| 34. |
- Heldt, Tobias, 1972-, et al.
(författare)
-
Samhällsekonomiska effekter av hästnäringen : Skattningar baserat på en B.I. – modell av hästnäringen för 2016
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport presenterar skattningar av den svenska hästnäringens samhällsekonomiska effekter på nationell och regional nivå. År 2016 uppskattades hästnäringen i Sverige generera en direkt omsättning på 31,3 miljarder kronor motsvarande en sysselsättning om ca 16 900 helårsarbetskrafter. Skattningarna bygger på en modell för hästnäringens samhällsekonomi som har sin utgångspunkt i summering av total konsumtion av hästrelaterade varor och tjänster i Sverige under ett år. Rapporten presenterar även den Business Intelligence (BI) lösning som ligger till grund samt hur bakgrundsdata har samlats in, lagrats och paketerats för att slutligen presenteras med hjälp av ett BI-verktyg (https://hastnaringen-i-siffror.se).
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| 35. |
- Heldt, Tobias, 1972-, et al.
(författare)
-
Svenska Skidspelen 2012 : Förstudie kring ekonomisk effekt- och konsumtionsmätning inför Skid-VM i Falun 2015
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport ska ses som en förstudie kring metoder för insamling av information över besökarna vid Svenska Skidspelen samt för att uppskatta Skidspelens ekonomiska betydelse. Resultaten baseras på insamlat material via enkäter till besökare till Skidspelen 2012. Totalt 404 svar i enkätform från besökare inom området samt från bil och bussåkande besökare har använts i analysen. Därutöver intervjuades 718 besökare vid entrén om ålder, bostadsort, vistelselängd samt färdmedel till evenemanget. Rapporten innehåller uppskattningar av Skidspelens ekonomiska betydelse med hjälp av flera typer av modeller; turism-, boende- samt ålderssegmenteringsmodell. Resultat från studien visar att engångskostnader för boende, resor och biljett kunde uppskattas relativt bra, medan konsumtion under dagen inte fångades tillräckligt bra i någon modell. Resultaten från studien visar också att en försiktig uppskattning av Skidspelens ekonomiska betydelse mätt som direkt konsumtion kan sägas ligga mellan 14 - 18 miljoner kr för år 2012. För att få ett mer korrekt resultat vid eventuella vidare studier eller vid studier av Skid-VM 2015 i Falun så bör en samhällsekonomisk välfärds analys göras för att inkludera samtliga effekter. Beräkningen av Skidspelens ekonomiska effekt skulle kunna göras mer precis genom att tillfråga ett större urval av besökare samt utveckla insamlingen av data över besökarnas totala konsumtion kopplat till besöket vid Svenska Skidspelen.
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| 36. |
- Huq, Asif M, et al.
(författare)
-
Friedman doctrine prevails! Or does it? : Evidence from the views of practitioners on corporate sustainability in their firms
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this paper is to provide insights on the views of firms regarding corporate sustainability (CS) and how the structure of the board affects this. We surveyed the CEOs, CFOs, and Environment Officers of about 850 Swedish firms (response rate 21%) affected by mandatory sustainability reporting after the implementation of the EU Directive 2014/95/EU. The six-transcending ambition levels (namely: pre-CS, compliance-driven, profit-driven, caring, synergistic, and holistic) of corporate sustainability proposed by van Marrewijk & Werre (2003) were used to classify the views of key officers on the sustainability agenda of their respective firms. We find that the drive by firms for higher CS ambition levels is positively influenced by a diverse board (i.e., representation of female board members), and the effect is more pronounced if the board is constituted with a female top executive. Moreover, younger top executives are more likely to have a higher CS ambition level. On the other hand, external CEOs, external board members, and forceful disclosure of sustainability activity (e.g., EU Directive 2014/95/EU) do not significantly influence CS ambition levels, whereas firm size and industry affiliation do. Our findings are useful for top managers and regulators interested in corporate governance issues and influencing the sustainability efforts of their firms. Methodologically, the use of a survey method is an extension to an otherwise high reliance on archival research in the field of CS. Furthermore, the dataset is unique, and the results are robust to various sensitivity analyses.
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| 37. |
- Huq, Asif M, et al.
(författare)
-
Measuring accountable information in CSR reports : A new operationalization and analysis applied to GHG disclosures
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The paper contributes to the debate if voluntary nonfinancial disclosures, such as greenhouse gas disclosures in corporate social responsibility reporting, exhibit accountability or are merely greenwashing. If firms exhibit accountability, does their actions translate into observable impacts, e.g., as country-level real changes in GHG emissions? How do contextual factors affect accountable disclosures in CSR reporting? To answer these questions, we develop a novel measure to classify accountable information of GHG disclosures in CSR reporting. We operationalize the measure using natural language processing tools, such as collocation analysis, regular expressions, and text mining. Statistical models were used to carry out aggregate analysis to detect real effects in GHG emissions reductions and firm-level analysis to investigate how institutional factors affect accountable GHG disclosures. We find that firms headquartered or reporting in a civil-law legal-environment disclose significantly higher accountable information compared to those in a common-law legal-environment. However, there is a negative trend in accountability worldwide, and firm-level accountability in GHG disclosures is not detectable in a country-level reduction of GHG emissions. The results are robust for various alternative model specifications, and operationalization of the developed measure achieved high concordance when investigated on random samples manually. Compared to most past studies, we work with a significantly larger sample of 4459 reports across 82 countries, thereby dealing with greater complexity and leading to better generalizability. In addition, developing an approach that is many folds scalable and makes replicability straightforward. This is also one of the few studies to move beyond the usual “bag-of-words” approach in classifying voluminous corporate disclosure using NLP techniques.
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| 38. |
- Håkansson, Johan, et al.
(författare)
-
Extended local labor markets due to high speed trains : Visualization of estimations in the Swedish national travel demand forecasting tool, SAMPERS
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Wider economic benefits resulting from extended geographical mobility is one argument for investments in high-speed rail. More specifically, the argument for high-speed trains in Sweden has been that they can help to further spatially extend labor market regions which in turn has a positive effect on growth and development. In this paper the aim is to cartographically visualize the potential size of the labor markets in areas that could be affected by possible future high-speed trains. The visualization is based on the forecasts of labor mobility with public transport made by the Swedish national mobility transport forecasting tool, SAMPERS, for two alternative high-speed rail scenarios. The analysis, not surprisingly, suggests that the largest impact of high-speed trains results in the area where the future high speed rail tracks are planned to be built. This expected effect on local labor market regions of high-speed trains could mean that possible regional economic development effects also are to be expected in this area. However, the results, in general, from the SAMPERS forecasts indicaterelatively small increases in local labor market potentials.
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| 39. |
- Håkansson, Johan, et al.
(författare)
-
How does employment density influence individuals’ wages? : A micro data approach.
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We estimate the effect of employment density on wages in Sweden in a large geocoded data set on individuals and workplaces. Employment density is measured in four circular zones around each individual’s place of living. The data contains a rich set of control variables that we use in an instrumental variables framework. Results show a relatively strong but rather local positive effect of employment density on wages. Beyond 5 kilometers the effect becomes negative. This might indicate that the effect of agglomeration economies falls faster with distance than the effects of congestion.
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| 40. |
- Håkansson, Johan, et al.
(författare)
-
Is the spatial scope of agglomeration economies on wages the same across the wage earnings distribution?
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We investigate the spatial scope of employment density across the wage distribution within four distance bands around each individual’s place of work. Observable and unobservable individual and workplace characteristics are controlled for. Remaining endogeneity in the wage model framework is assessed with an IV approach. Results indicate a positive effect of employment density on wages within 5 kilometres. The effect is negative beyond 50 kilometres. The spatial scope of employment density is larger at the higher end of the wage distribution but the effect closest to the establishment seems larger at the lower end of the wage distribution.
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| 41. |
- Håkansson, Johan, et al.
(författare)
-
Stayers and movers : Understanding the sorting dynamics that cause socio-economic residential segregation
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Although many argue that residential segregation is related to selective migration, certainly in Sweden, this view has recently been somewhat challenged when a broader demographic analysis, the so-called demographic conveyer approach, has been used to study the segregation process. However, the number of studies and cases using the demographic conveyer approach to study segregation is limited. In this paper, we apply an elaborated demographic conveyer approach in a new context to describe and analyse the underlying sorting dynamics that over time cause residential segregation. To do so, we follow the individual’s socio-economic carriers, between 1990 and 2008 in three neighbourhoods that have become socio-economically weak. We compare the career outcomes of stayers, in-migrants and out-migrants, and by doing so, we draw conclusions about the underlying dynamics that cause socio-economic segregation. The analysis is conducted in a medium-sized Swedish city which has rapidly become highly segregated since the early 1990s, making it possible to basically follow the evolution of the current segregated situation. Our main conclusion is that the segregation process is due to migration, however, not to internal migration, but rather external immigration. The degree of segregation is highly related to institutional circumstances, since immigrants basically settle in dwellings owned by the public housing company. In our case, the public housing apartments are highly concentrated to the studied area. We also find a general improvement in socio-economic situations regarding both educational levels and unemployment levels for in-migrants, out-migrants and stayers. However, the relationship between the inflows and outflows changes essentially from a situation when the inflows improved the population’s socio-economic status to a situation where the reverse is true. This is accentuated when income is taken into account. The paper also shows that individuals moving away from a segregated neighbourhood, who do not end up in similar neighbourhoods in the city, have better socio-economic carriers than those who stay in one of the three neighbourhoods during the period.
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| 42. |
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| 43. |
- Jomaa, Diala, 1978-, et al.
(författare)
-
Speed prediction for triggering vehicle activated signs
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Accurate speed prediction is a crucial step in the development of a dynamic vehcile activated sign (VAS). A previous study showed that the optimal trigger speed of such signs will need to be pre-determined according to the nature of the site and to the traffic conditions. The objective of this paper is to find an accurate predictive model based on historical traffic speed data to derive the optimal trigger speed for such signs. Adaptive neuro fuzzy (ANFIS), classification and regression tree (CART) and random forest (RF) were developed to predict one step ahead speed during all times of the day. The developed models were evaluated and compared to the results obtained from artificial neural network (ANN), multiple linear regression (MLR) and naïve prediction using traffic speed data collected at four sites located in Sweden. The data were aggregated into two periods, a short term period (5-min) and a long term period (1-hour). The results of this study showed that using RF is a promising method for predicting mean speed in the two proposed periods.. It is concluded that in terms of performance and computational complexity, a simplistic input features to the predicitive model gave a marked increase in the response time of the model whilse still delivering a low prediction error.
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| 44. |
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| 45. |
- Lee, Youngjo, et al.
(författare)
-
Estimating zones of influence using threshold regression
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In environmental impact assessments, it is important to be able to estimate influence of anthropogenic activities on animal populations. To quantify the influence, it is common to estimate how far, in distance, from a given disturbance source there is an influence on the animals’ habitat selection through estimating a zone of influence (ZOI). Usually, ZOI is estimated for one disturbance source at a time. In this work, we demonstrate how threshold regression modelling can be used for estimating ZOI from several possible sources of disturbances, simultaneously. Based on the theoretical properties of different estimation methods for the estimation of threshold regression we select a set of estimation methods and compare their merits through a simulation study and a real data example. The simulation results revealed that Adaptive Lasso, and Hierarchical likelihood (HL) methods, are two reasonable methods for dealing with the problem. HL performed better than Adaptive Lasso in that it had much higher success rate in identifying correct threshold with small sample size whereas Adaptive Lasso requires large sample to assure good performance. While Adaptive lasso needed to be aided with suitable weights, which are not easy to find, HL method did not require any prior weights. These two methods were applied to estimate the ZOI around 40 wind turbines and surrounding public roads on reindeer habitat selection in winter, by using GPS positioning data from 42 reindeer in north of Sweden in December to March (2012-2015). The results showed that both the disturbance sources have a negative effect on reindeer habitat selection in winter. The HL approach showed that the negative ZOI from the nearest wind turbine was 1.8 km (approx.), however the trend of higher selection of areas further away from the wind turbines was evident up to 4 km (approx.) from the active wind turbines.
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| 46. |
- Li, Dao, et al.
(författare)
-
Forecasting with Vector Nonlinear Time Series Models
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 47. |
- Li, Dao
(författare)
-
Residual-based Inference for Common Nonlinear Features
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 48. |
- Li, Dao, et al.
(författare)
-
Testing common nonlinear features in vector nonlinear autoregressive models
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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).
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| 49. |
- Li, Dao
(författare)
-
Testing linear cointegration against smooth-transition cointegration
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 50. |
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