du.sePublications
Change search
Refine search result
12 1 - 50 of 94
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Aghanavesi, Somayeh
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Smartphone-based Parkinson’s disease symptom assessment2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of four research papers presenting a microdata analysis approach to assess and evaluate the Parkinson’s disease (PD) motor symptoms using smartphone-based systems. PD is a progressive neurological disorder that is characterized by motor symptoms. It is a complex disease that requires continuous monitoring and multidimensional symptom analysis. Both patients’ perception regarding common symptom and their motor function need to be related to the repeated and time-stamped assessment; with this, the full extent of patient’s condition could be revealed. The smartphone enables and facilitates the remote, long-term and repeated assessment of PD symptoms. Two types of collected data from smartphone were used, one during a three year, and another during one-day clinical study. The data were collected from series of tests consisting of tapping and spiral motor tests. During the second time scale data collection, along smartphone-based measurements patients were video recorded while performing standardized motor tasks according to Unified Parkinson’s disease rating scales (UPDRS).

    At first, the objective of this thesis was to elaborate the state of the art, sensor systems, and measures that were used to detect, assess and quantify the four cardinal and dyskinetic motor symptoms. This was done through a review study. The review showed that smartphones as the new generation of sensing devices are preferred since they are considered as part of patients’ daily accessories, they are available and they include high-resolution activity data. Smartphones can capture important measures such as forces, acceleration and radial displacements that are useful for assessing PD motor symptoms.

    Through the obtained insights from the review study, the second objective of this thesis was to investigate whether a combination of tapping and spiral drawing tests could be useful to quantify dexterity in PD. More specifically, the aim was to develop data-driven methods to quantify and characterize dexterity in PD. The results from this study showed that tapping and spiral drawing tests that were collected by smartphone can detect movements reasonably well related to under- and over-medication.

    The thesis continued by developing an Approximate Entropy (ApEn)-based method, which aimed to measure the amount of temporal irregularity during spiral drawing tests. One of the disabilities associated with PD is the impaired ability to accurately time movements. The increase in timing variability among patients when compared to healthy subjects, suggests that the Basal Ganglia (BG) has a role in interval timing. ApEn method was used to measure temporal irregularity score (TIS) which could significantly differentiate the healthy subjects and patients at different stages of the disease. This method was compared to two other methods which were used to measure the overall drawing impairment and shakiness. TIS had better reliability and responsiveness compared to the other methods. However, in contrast to other methods, the mean scores of the ApEn-based method improved significantly during a 3-year clinical study, indicating a possible impact of pathological BG oscillations in temporal control during spiral drawing tasks. In addition, due to the data collection scheme, the study was limited to have no gold standard for validating the TIS. However, the study continued to further investigate the findings using another screen resolution, new dataset, new patient groups, and for shorter term measurements. The new dataset included the clinical assessments of patients while they performed tests according to UPDRS. The results of this study confirmed the findings in the previous study. Further investigation when assessing the correlation of TIS to clinical ratings showed the amount of temporal irregularity present in the spiral drawing cannot be detected during clinical assessment since TIS is an upper limb high frequency-based measure. 

  • 2.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Bergquist, Filip
    Gothenburg University.
    Nyholm, Dag
    Uppsala University.
    Senek, Marina
    Uppsala University.
    Memedi, Mevludin
    Örebro University.
    Objective assessment of Parkinson’s disease motor symptoms during leg agility test using motion sensors2018Conference paper (Refereed)
    Abstract [en]

    Title: Objective assessment of Parkinson’s disease motor symptoms during leg agility test using motion sensors

    Objective: To develop and evaluate machine learning methods for assessment of Parkinson’s disease (PD) motor symptoms using leg agility (LA) data collected with motion sensors during a single dose experiment.

    Background: Nineteen advanced PD patients (Gender: 14 males and 5 females, mean age: 71.4, mean years with PD: 9.7, mean years with levodopa: 9.5) were recruited in a single center, open label, single dose clinical trial in Sweden [1].

    Methods: The patients performed up to 15 LA tasks while wearing motions sensors on their foot ankle. They performed tests at pre-defined time points starting from baseline, at the time they received a morning dose (150% of their levodopa equivalent morning dose), and at follow-up time points until the medication wore off. The patients were video recorded while performing the motor tasks. and three movement disorder experts rated the observed motor symptoms using 4 items from the Unified PD Rating Scale (UPDRS) motor section including UPDRS #26 (leg agility), UPDRS #27 (Arising from chair), UPDRS #29 (Gait), UPDRS #31 (Body Bradykinesia and Hypokinesia), and dyskinesia scale. In addition, they rated the overall mobility of the patients using Treatment Response Scale (TRS), ranging from -3 (very off) to 3 (very dyskinetic). Sensors data were processed and their quantitative measures were used to develop machine learning methods, which mapped them to the mean ratings of the three raters. The quality of measurements of the machine learning methods was assessed by convergence validity, test-retest reliability and sensitivity to treatment.

    Results: Results from the 10-fold cross validation showed good convergent validity of the machine learning methods (Support Vector Machines, SVM) with correlation coefficients of 0.81 for TRS, 0.78 for UPDRS #26, 0.69 for UPDRS #27, 0.78 for UPDRS #29, 0.83 for UPDRS #31, and 0.67 for dyskinesia scale (P<0.001). There were good correlations between scores produced by the methods during the first (baseline) and second tests with coefficients ranging from 0.58 to 0.96, indicating good test-retest reliability. The machine learning methods had lower sensitivity than mean clinical ratings (Figure. 1).

    Conclusions: The presented methodology was able to assess motor symptoms in PD well, comparable to movement disorder experts. The leg agility test did not reflect treatment related changes.

  • 3.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Filip, Bergquist
    Gothenburg University.
    Nyholm, Dag
    Uppsala University.
    Senek, Marina
    Uppsala University.
    Memedi, Mevludin
    Örebro University.
    Feasibility of a multi-sensor data fusion method for assessment of Parkinson’s disease motor symptoms2018Conference paper (Refereed)
    Abstract [en]

    Title: Feasibility of a multi-sensor data fusion method for assessment of Parkinson’s disease motor symptoms

    Objective: To assess the feasibility of measuring Parkinson’s disease (PD) motor symptoms with a multi-sensor data fusion method. More specifically, the aim is to assess validity, reliability and sensitivity to treatment of the methods.

    Background: Data from 19 advanced PD patients (Gender: 14 males and 5 females, mean age: 71.4, mean years with PD: 9.7, mean years with levodopa: 9.5) were collected in a single center, open label, single dose clinical trial in Sweden [1].

    Methods: The patients performed leg agility and 2-5 meter straight walking tests while wearing motion sensors on their limbs. They performed the tests at baseline, at the time they received the morning dose, and at pre-specified time points until the medication wore off. While performing the tests the patients were video recorded. The videos were observed by three movement disorder specialists who rated the symptoms using a treatment response scale (TRS), ranging from -3 (very off) to 3 (very dyskinetic). The sensor data consisted of lower limb data during leg agility, upper limb data during walking, and lower limb data during walking. Time series analysis was performed on the raw sensor data extracted from 17 patients to derive a set of quantitative measures, which were then used during machine learning to be mapped to mean ratings of the three raters on the TRS scale. Combinations of data were tested during the machine learning procedure.

    Results: Using data from both tests, the Support Vector Machines (SVM) could predict the motor states of the patients on the TRS scale with a good agreement in relation to the mean ratings of the three raters (correlation coefficient = 0.92, root mean square error = 0.42, p<0.001). Additionally, there was good test-retest reliability of the SVM scores during baseline and second tests with intraclass-correlation coefficient of 0.84. Sensitivity to treatment for SVM was good (Figure 1), indicating its ability to detect changes in motor symptoms. The upper limb data during walking was more informative than lower limb data during walking since SVMs had higher correlation coefficient to mean ratings.  

    Conclusions: The methodology demonstrates good validity, reliability, and sensitivity to treatment. This indicates that it could be useful for individualized optimization of treatments among PD patients, leading to an improvement in health-related quality of life.

  • 4.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Memedi, Mevludin
    Dalarna University, School of Technology and Business Studies, Computer Engineering. Örebro universitet.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Nyholm, Dag
    Uppsala universitet.
    Westin, Jerker
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Verification of a method for measuring Parkinson's disease related temporal irregularity in spiral drawings2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 10, article id E2341Article in journal (Refereed)
    Abstract [en]

    Parkinson's disease (PD) is a progressive movement disorder caused by the death of dopamine-producing cells in the midbrain. There is a need for frequent symptom assessment, since the treatment needs to be individualized as the disease progresses. The aim of this paper was to verify and further investigate the clinimetric properties of an entropy-based method for measuring PD-related upper limb temporal irregularities during spiral drawing tasks. More specifically, properties of a temporal irregularity score (TIS) for patients at different stages of PD, and medication time points were investigated. Nineteen PD patients and 22 healthy controls performed repeated spiral drawing tasks on a smartphone. Patients performed the tests before a single levodopa dose and at specific time intervals after the dose was given. Three movement disorder specialists rated videos of the patients based on the unified PD rating scale (UPDRS) and the Dyskinesia scale. Differences in mean TIS between the groups of patients and healthy subjects were assessed. Test-retest reliability of the TIS was measured. The ability of TIS to detect changes from baseline (before medication) to later time points was investigated. Correlations between TIS and clinical rating scores were assessed. The mean TIS was significantly different between healthy subjects and patients in advanced groups (p-value = 0.02). Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia) were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high-frequency-based measure, it cannot be detected during clinical assessment.

  • 5.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Nyholm, Dag
    Marina, Senek
    Bergquist, Filip
    Memedi, Mevludin
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    A smartphone-based system to quantify dexterity in Parkinson's disease patients2017In: Informatics in Medicine Unlocked, ISSN 2352-9148, Vol. 9, p. 11-17Article in journal (Refereed)
    Abstract [en]

    Objectives: The aim of this paper is to investigate whether a smartphone-based system can be used to quantify dexterity in Parkinson’s disease (PD). More specifically, the aim was to develop data-driven methods to quantify and characterize dexterity in PD. Methods: Nineteen advanced PD patients and 22 healthy controls participated in a clinical trial in Uppsala, Sweden. The subjects were asked to perform tapping and spiral drawing tests using a smartphone. Patients performed the tests before, and at pre-specified time points after they received 150% of their usual levodopa morning dose. Patients were video recorded and their motor symptoms were assessed by three movement disorder specialists using three Unified PD Rating Scale (UPDRS) motor items from part III, the dyskinesia scoring and the treatment response scale (TRS). The raw tapping and spiral data were processed and analyzed with time series analysis techniques to extract 37 spatiotemporal features. For each of the five scales, separate machine learning models were built and tested by using principal components of the features as predictors and mean ratings of the three specialists as target variables. Results: There were weak to moderate correlations between smartphone-based scores and mean ratings of UPDRS item #23 (0.52; finger tapping), UPDRS #25 (0.47; rapid alternating movements of hands), UPDRS #31 (0.57; body bradykinesia and hypokinesia), sum of the three UPDRS items (0.46), dyskinesia (0.64), and TRS (0.59). When assessing the test-retest reliability of the scores it was found that, in general, the clinical scores had better test-retest reliability than the smartphone-based scores. Only the smartphone-based predicted scores on the TRS and dyskinesia scales had good repeatability with intra-class correlation coefficients of 0.51 and 0.84, respectively. Clinician-based scores had higher effect sizes than smartphone-based scores indicating a better responsiveness in detecting changes in relation to treatment interventions. However, the first principal component of the 37 features was able to capture changes throughout the levodopa cycle and had trends similar to the clinical TRS and dyskinesia scales. Smartphone-based scores differed significantly between patients and healthy controls. Conclusions: Quantifying PD motor symptoms via instrumented, dexterity tests employed in a smartphone is feasible and data from such tests can also be used for measuring treatment-related changes in patients.

  • 6.
    Ahmed, Salim Saif Saeed
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Identify the driving behaviour in a parking lot in terms of distance.2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Parking a vehicle can often lead to frustration, air pollution and congestion due to limited availability of parking spaces. With increasing population density this problem can certainly increase unless addressed. Parking lots occupy large areas of scarce land resource therefore it is necessary to identify the driving behaviour in a parking lot to improve it further. This Paper tries study the driving behaviour in the parking lot and for this endeavours it conducted direct observation in three parking lots and used GPS data that was collected prior to this study by the University of Dalarna.

    To evaluate the driving behaviour in the parking lot direct observation was conducted to obtain overall indices of the parking lot vehicles movement. The parking route taken by the driver was compared with the optimal path to identify the driving behaviour in parking lot in terms of distance. The collected data was evaluated, filtered and analysed to identify the route, the distance and the time the vehicle takes to find a parking space.

    The outcome of the study shows that driving behaviour in the parking lots varies significantly among the parking user where most of the observed vehicles took unnecessary long time to complete their parking. The study shows that 56% of the 430 observed vehicles demonstrated inefficient driving behaviour as they took long driving path rather the than the optimal path. The study trace this behaviour to two factors, first, the absent of parking guidance in the parking lots and the second is the selectivity of the drivers when choosing the parking space.

    The study also shows that the ability of GPS data to identify the driving behaviour in the parking lots varies based on the time interval and the type of the device that is being used. The small the time interval the more accurate the GPS data in detecting the driving behaviour in the parking lots.

  • 7.
    Al-Soloh, Mohanad
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Al-Isawi, Arkan
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Robustness in constructing a network of induced emissions based on GPS-tracking data2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The mobility of people, freight and information is fundamental to economic and social activities such as commuting, manufacturing, distributing consumer goods and supplying energy. There are two major problems that arise as a result of mobility. The first is economic cost and the second is environmental impact which is of increasing concern in sustainable development due to emission levels, particularly as a result of car use. This study focuses on constructing a network of induced emissions (NOIEs) by using three models and checking the robustness of NOIEs under varying parameters and models. The three models are Stead’s model, the NAEI model, and Oguchi’s model. This study uses the Swedish city of Borlänge as the case study.

    Calculating CO2 emissions by constructing the NOIEs using Stead’s model appears to give an underestimation when compared to results from a NOIEs which applies Oguchi’s model. Results when applying the NAEI model in constructing a NOIEs also give an underestimation compared to a NOIEs applying Oguchi’s model. Applying the NAEI model is, however, more accurate than applying Stead’s model in constructing a NOIEs.

    The outcomes of this study show that constructing a NOIEs is robust using Oguchi’s model. This model is preferable since it takes into account more important variables such as driving behavior and the length of the road segments which have a significant impact when estimating CO2 emissions.

  • 8.
    Barcik, Robert
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Assessment of Parkinson gait through digital signal processing and machine learning2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It would be of both patients’ as well as clinicians’ interest, if diagnosis of Parkinson’s disease (PD) as well as following check-up methods were perfectly sensitive, accurate, reproducible and feasible of objectively classifying motor symptoms of PD. This is an arduous task due to the possible subjectivity of clinical evaluations. In the past decade, attention turns into a multitude of technology based measures (TBMs) to address this need, among which the method of this research is positioned. Author hopes to contribute with a motor assessment method that addresses not only the issue of subjectivity of measurement, but also does not require extensive installments and is easy to use. For this study, data from a clinical trial conducted at Uppsala University Hospital, Sweden in 2015 are used. 7 PD patients and 7 healthy controls each performed 7-13 times each the same motoric gait test, which has been was video recorded. These recordings were showed to clinicians, who rated subjects’ gait and possible dyskinesia on the unified Parkinson's disease rating scale (0-4 rating). Thus the aim of this research was to imitate and automate the tasks of clinicians when diagnosing PD and its symptoms through motoric ratings, using various gait features. These gait features were obtained through quantification of signals from different body parts while patient performs walking motoric test, using image processing. Diagnosis of PD and its symptoms was twofold, as to firstly identify whether the subject has PD and to secondly predict the severity of PD patients symptoms. When classifying subjects into healthy controls and PD patients, classification trees and support vector machines have been deployed, while these achieved 76- 85% accuracy depending on features selected. Following focus was to diagnose severity of PD among patients, while using UPDRS ratings by clinicians as a target variable for supervised learning. Herein, linear regression has been deployed, while average absolute prediction error was 0.25 and correlation of UPDRS ratings with predicted values was 0.84.

  • 9.
    Cai, Cai
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    An application of gravity p-median model with different distance decay functions2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The location-allocation problem has been studied over 50 years and recently a

    new method called “gravity p-median model” is introduced to the public. The key

    idea is that the probability of customers visit a facility is based on a distance decay

    function rather than directly choose the nearest one. An empirical test shows that the

    solution of gravity p-median model with exponential distance decay function is

    unstable and of limit use.

    This paper extends the research to apply gravity p-median model with three

    different distance decay functions in Dalecarlia, Sweden. The distance decay

    functions are estimated from a Swedish survey by maximum likelihood estimation.

    The models are optimized by simulated annealing. The result suggests that different

    distance decay functions dominate the solutions of gravity p-median model, and the

    log-normal decay function can provide stable solutions.

  • 10.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    A comment on outlier detection and skewed distributions2017Report (Other academic)
    Abstract [en]

    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).

  • 11.
    Carling, Kenneth
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Meng, Xiangli
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics. HUI Research, Stockholm.
    The effect on CO2 emissions of taxing truck distance in retail transports2017In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 97, p. 47-54Article in journal (Refereed)
    Abstract [en]

    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 competitive retail and transportation markets, 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.

  • 12.
    Carling, Kenneth
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Li, Yujiao
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    The Power of the Synthetic Control Method2016Report (Other academic)
    Abstract [en]

    The synthetic control method (SCM) is a new, popular method developed for the purpose of estimating the effect of an intervention when only one single unit has been exposed. Other similar, unexposed units are combined into a synthetic control unit intended to mimic the evolution in the exposed unit, had it not been subject to exposure. As the inference relies on only a single observational unit, the statistical inferential issue is a challenge. In this paper, we examine the statistical properties of the estimator, study a number of features potentially yielding uncertainty in the estimator, discuss the rationale for statistical inference in relation to SCM, and provide a Web-app for researchers to aid in their decision of whether SCM is powerful for a specific case study. We conclude that SCM is powerful with a limited number of controls in the donor pool and a fairly short pre-intervention time period. This holds as long as the parameter of interest is a parametric specification of the intervention effect, and the duration of post-intervention period is reasonably long, and the fit of the synthetic control unit to the exposed unit in the pre-intervention period is good.

  • 13.
    Chen, Chuandong
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    The effects of shadow banking on bank efficiency:Evidence from China2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study examines the effects of shadow banking on bank efficiency using data onChinese commercial banks during the period 1998–2012. I focus on two aspects: shadowbanking activities inside and outside the commercial banks. Stochastic frontier analysis(SFA) is used to analyze the effects of shadow banking on cost-efficiency. The empiricalresults indicate that the higher relative size of shadow banking inside the commercialbanks, the higher bank cost-efficiency is, while the higher relative size of shadow bankingoutside the commercial banks, the lower cost-efficiency is. This shows that there are gainsfrom shadow banking for the Chinese financial system. It is important for policymakers torealize this but at the same time understand that shadow banking likely implies a tradeoffbetween flexibility for the banking sector and higher risks.

  • 14.
    Cialani, Catia
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis. Dalarna University.
    Mortazavi, Reza
    Dalarna University, School of Technology and Business Studies, Microdata Analysis. Dalarna University.
    Household and industrial electricity demand in Europe2018In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 122, p. 592-600Article in journal (Refereed)
    Abstract [en]

    This paper examines the electricity demand, and its determinants, in 29 European countries during the liberalization of the electricity market. Based on panel data for these countries for the years 1995–2015 and using a dynamic partial adjustment model, price elasticities are estimated for both residential and industrial electricity demand. These elasticities and effects of other variables on electricity consumption are estimated using both GMM (generalized method of moments) and ML (maximum likelihood) approaches. It is found that the price elasticities are very small, especially in the short run, while the income elasticities are relatively large, especially for households and in the long run.

  • 15.
    Daunfeldt, Sven-Olov
    et al.
    Dalarna University, School of Technology and Business Studies, Economics.
    Grek, Åsa
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics.
    Betydelsen av internt genererat kapital för en långsiktigt hållbar företagstillväxt2017In: Perspektiv på kapitalförsörjning – en antologi om företagens finansiering och statens roll / [ed] Jörgen Lithander, Stockholm: Tillväxtanalys , 2017, 1, p. 31-49Chapter in book (Other academic)
    Abstract [sv]

    Ett företags expansion kan finansieras med internt genererat kapital eller med hjälp av extern finansiering. Vi undersöker här hur omsättningstillväxten och överlevnadssannolikheten påverkas av företagets internt uppbyggda kapital. Undersökningen baseras på data över alla Sveriges aktiebolag under perioden 1997–2010.

    Våra resultat indikerar att den initiala tillgången på internt uppbyggt kapital generellt sett inte är förknippad med en högre omsättningstillväxt eller ökade möjligheter att överleva på marknaden. Vi finner däremot att de företag som bygger upp interna medel innan de växer är mer sannolika att uppnå en långsiktigt hållbar tillväxt än de företag som växer innan de byggt upp ett internt kapital.

    Resultaten indikerar också att företag som har varit med om uppköp eller sammanslagningar har både högre tillväxt och bättre chanser att överleva på marknaden.

    Vi kan samtidigt konstatera att de skattade sambanden ofta är svaga trots det omfattande datamaterialet. Det tyder på att företagstillväxt i huvudsak är slumpmässig eller kan förklaras av variabler som är svåra att mäta och inkludera i kvantitativ analys. Detta bekräftas också av tidigare studier.

    Våra resultat implicerar att framtida studier bör fokusera mer på hur företagen växer än på vad som kan förklara hur mycket de växer vid en viss tidpunkt.

  • 16.
    Daunfeldt, Sven-Olov
    et al.
    Dalarna University, School of Technology and Business Studies, Economics.
    Grek, Åsa
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics.
    Hur kapitalstrukturen påverkar den långsiktigt hållbara företagstillväxten2017Report (Other academic)
    Abstract [sv]

    Det antas ofta att det finns ett ”kapitalförsörjningsgap” i ekonomin på grund av asymmetrisk information, vilket leder till att efterfrågan på externt kapital är större än utbudet. De politiska beslutsfattarna vill därför ofta öka tillgången på externt riskkapital genom olika selektiva statliga stödinsatser för att få fler växande företag.

    Klassiska teorier om företagstillväxt implicerar dock att det snarare är uppbyggnaden av företagets interna resurser som är av betydelse för att förklara företagens tillväxt och möjligheter att överleva på marknaden. Många företagare vill dessutom behålla kontrollen över sitt företag och kan därmed välja att inte växa med externt kapital, trots att de har tillväxtambitioner. Om detta stämmer är politiska beslut som ökar tillgången till internt kapital av större betydelse för företagens utveckling än politiska beslut som avser att öka tillgången på externt kapital.

    I denna rapport vill vi studera hur betydelsefullt det internt uppbyggda kapitalet har varit för tillväxt och överlevnad hos aktiebolag i Sverige under perioden 1997–2010. Våra resultat indikerar att:

    • Tillgången till internt kapital kan inte förklara den observerade företagstillväxten bland aktiebolag i Sverige under perioden 1997–2010.

    • Det interna kapitalet är inte relaterat till överlevnadssannolikheten för aktiebolag i Sverige under perioden 1997–2010.

    • Företag som växer efter att de har byggt upp internt kapital har större möjligheter att i framtiden kombinera hög tillväxt med hög lönsamhet jämfört med de företag som växer innan de har byggt upp internt kapital.

    Resultaten är delvis motstridiga. De företag som bygger upp ett internt kapital och sedan väljer att expandera har en högre sannolikhet att nå en långsiktigt hållbar position för tillväxt än de företag som växer innan de har byggt upp internt kapital. Detta talar för att uppbyggnaden av internt kapital är av betydelse. Våra regressionsresultat indikerar dock att det inte finns något starkt positivt samband mellan internt uppbyggt kapital och företagens framtida omsättningstillväxt eller möjligheter att överlevna på marknaden.

    Det finns ett antal möjliga förklaringar till våra resultat. Den första förklaringen är helt enkelt att det interna kapitalet inte är av betydelse för företagens framtida tillväxt och överlevnad. Den troliga förklaringen till detta är att vid jämvikt kommer företagarna att värdesätta en expansion med internt eller externt kapital på liknande sätt. Detta implicerar att det snarare är den totala mängden riskkapital som påverkar företagens tillväxt och överlevnad, och inte huruvida kapitalet genereras internt eller externt.

    En annan tolkning är att företagarna fortfarande föredrar att växa med internt uppbyggt kapital eftersom resultaten visar effekten på företagstillväxten och överlevnadssannolikheten, givet den initiala uppbyggnaden av internt kapital i företagen. Den initiala nivån av internt kapital har således ingen effekt på företagsutvecklingen, men en ökning av det interna kapitalet i förhållande till tillgången på externt kapital kan fortfarande leda till att fler företag vill expandera sin verksamhet.

    Många företagare i Sverige väljer också att inte växa trots att de har relativt god lönsamhetsutveckling. Detta kan betyda att vi inte observerar några samband mellan det internt uppbyggda kapitalet och företagens utveckling eftersom många företagare inte vill växa under de rådande institutionella förutsättningarna. Det finns med andra ord utelämnande variabler, till exempel olika tillväxtbarriärer (regelkrångel, strikt anställningsskydd, matchningsproblem, etc.), som kan förklara varför det interna kapitalet inte har någon observerad betydelse för tillväxten och företagens överlevnad i vår studie.

    Slutligen kan en möjlig förklaring vara att företagens tillväxt och överlevnad i mycket hög utsträckning är slumpmässig. Detta innebär att det blir svårt att förklara vad det är som påverkar företagens utveckling, vilket också implicerar att selektiva stödåtgärder för att få fler växande företag är dömda att misslyckas.

    Sammanfattningsvis kan vi konstatera att våra resultat inte ger något stöd för hypotesen att företag med tillgång till internt kapital växer snabbare och har en högre överlevnadssannolikhet än de företag som har tillgång till mindre internt uppbyggt kapital. Resultaten bygger på de rådande institutionella förutsättningarna i Sverige under perioden 1997–2010 och är avgränsade till att studera effekten av det initialt uppbyggda kapitalet i bolagen. Vi undersöker inte företagarnas preferenser, det vill säga om de föredrar mer internt kapital framför externt kapital när de ska expandera verksamheten, eller om en ökning av det internt uppbyggda kapitalet har en större tillväxteffekt än mer externt kapital.

  • 17.
    Daunfeldt, Sven-Olov
    et al.
    Dalarna University, School of Technology and Business Studies, Economics. HUI Research, Stockholm.
    Mihaescu, Oana
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Nilsson, Helena
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics.
    What happens when IKEA comes to town?2017In: Regional studies, ISSN 0034-3404, E-ISSN 1360-0591, Vol. 51, no 2, p. 313-323Article in journal (Refereed)
    Abstract [en]

    The effects of a new IKEA store on retail revenues, employment and inflow of purchasing power in the entry municipalities as well as in neighbouring municipalities were investigated using data from 2000–11. A propensity score-matching method was used to find non-IKEA entry municipalities that were as similar as possible to the entry municipalities based on the situation before entry. The results indicate that IKEA entry increased entry municipality durable goods revenues by about 20% and employment by about 17%. Only small and, in most cases, statistically insignificant effects were found in neighbouring municipalities.

  • 18.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Something old, something new, something borrowed, something blue: Part 3 - An elephant never forgets2017In: Journal of Intelligent Systems, ISSN 0334-1860, E-ISSN 2191-026X, Vol. 26, no 3, p. 433-437Article in journal (Refereed)
    Abstract [en]

    Forgetting is an oft-forgotten art. Many artificial intelligence (AI) systems deliver good performance when first implemented; however, as the contextual environment changes, they become out of date and their performance degrades. Learning new knowledge is part of the solution, but forgetting outdated facts and information is a vital part of the process of renewal. However, forgetting proves to be a surprisingly difficult concept to either understand or implement. Much of AI is based on analogies with natural systems, and although all of us have plenty of experiences with having forgotten something, as yet we have only an incomplete picture of how this process occurs in the brain. A recent judgment by the European Court concerns the "right to be forgotten" by web index services such as Google. This has made debate and research into the concept of forgetting very urgent. Given the rapid growth in requests for pages to be forgotten, it is clear that the process will have to be automated and that intelligent systems of forgetting are required in order to meet this challenge.

  • 19.
    Dutra Calainho, Felipe
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Evaluation of Calibration Methods to Adjust for Infrequent Values in Data for Machine Learning2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The performance of supervised machine learning algorithms is highly dependent on the distribution of the target variable. Infrequent values are more di_cult to predict, as there are fewer examples for the algorithm to learn patterns that contain those values. These infrequent values are a common problem with real data, being the object of interest in many _elds such as medical research, _nance and economics, just to mention a few. Problems regarding classi_cation have been comprehensively studied. For regression, on the other hand, few contributions are available. In this work, two ensemble methods from classi_cation are adapted to the regression case. Additionally, existing oversampling techniques, namely SmoteR, are tested. Therefore, the aim of this research is to examine the inuence of oversampling and ensemble techniques over the accuracy of regression models when predicting infrequent values. To assess the performance of the proposed techniques, two data sets are used: one concerning house prices, while the other regards patients with Parkinson's Disease. The _ndings corroborate the usefulness of the techniques for reducing the prediction error of infrequent observations. In the best case, the proposed Random Distribution Sample Ensemble reduced the overall RMSE by 8.09% and the RMSE for infrequent values by 6.44% when compared with the best performing benchmark for the housing data set.

  • 20.
    Eriksson, Per Erik
    et al.
    Dalarna University, School of Humanities and Media Studies, Moving Image Production.
    Swenberg, Thorbjörn
    Dalarna University, School of Humanities and Media Studies, Moving Image Production.
    Zhao, Xiaoyun
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Eriksson, Yvonne
    Mälardalens Högskola / IPR.
    How gaze time on screen impacts the efficacy of visual instructions2018In: Heliyon, ISSN 2405-8440, Vol. 4, no 6, article id e00660Article in journal (Refereed)
    Abstract [en]

    This article explores whether GTS (gaze time on screen) can be useful as an engagement measure in the screen mediated learning context. Research that exemplifies ways of measuring engagement in the on-line education context usually does not address engagement metrics and engagement evaluation methods that are unique to the diverse contemporary instructional media landscape. Nevertheless, unambiguous construct definitions of engagement and standardized engagement evaluation methods are needed to leverage instructional media's efficacy. By analyzing the results from a mixed methods eye-tracking study of fifty-seven participants evaluating their visual and assembly performance levels in relation to three visual, procedural instructions that are versions of the same procedural instruction, we found that the mean GTS-values in each group were rather similar. However, the original GTS-values outputted from the ET-computer were not entirely correct and needed to be manually checked and cross validated. Thus, GTS appears not to be a reliable, universally applicable automatic engagement measure in screen-based instructional efforts. Still, we could establish that the overall performance of learners was somewhat negatively impacted by lower than mean GTS-scores, when checking the performance levels of the entire group (N = 57). When checking the stimuli groups individually (N = 17, 20, 20), the structural diagram group's assembly time durations were positively influenced by higher than mean GTS-scores.

  • 21.
    Espegren, Yanina
    et al.
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Carling, Kenneth
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Olsmats, Carl
    Dalarna University, School of Technology and Business Studies, Industrial Engineering and Management.
    Smart online grocery delivery and peri-urbanconsumers’ attitudes2018Report (Other academic)
    Abstract [en]

    Purpose: To explore consumers’ attitudes towards e-commerce, in particular online grocery shopping, and its delivery in non-dense areas for the purpose of designing smart last-mile solutions.

    Approach: The state-of-the-art of smart e-commerce delivery in dense areas was identified by a review of the literature. It was expected that this knowledge could be transferred to non-dense areas. This prediction was examined and explored further by making use of four focus groups recruited in a Swedish mid-sized town.

    Findings: Respondents were generally positive towards e-commerce, although mixed attitudes were found with regard to online grocery shopping. Further, the willingness to pay for flexible, smart and sustainable delivery was low, with a notable exception for local produce.

    Originality: The knowledge acquired and solution developed in dense areas is not readily transferred to non-dense areas. There is scope for developing new Business Models for the supply chain of local produce. For the prototype testing and roll-out of smart e-commerce delivery platforms, the online local produce market is recommended.

  • 22.
    Fahlström, Magnus
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Mathematics teachers’ conceptions of the classroom environment2017In: Teaching and Learning in Maths Classrooms: Emerging Themes in Affect-related Research: Teachers' Beliefs, Students' Engagement and Social Interaction / [ed] Chiara Andrà, Domenico Brunetto, Esther Levenson, Peter Liljedahl, Springer, 2017, p. 141-151Chapter in book (Refereed)
    Abstract [en]

    This study explores mathematics teachers’ conceptions of how the physical environment in classrooms affects their students’ chances for learning. Semi structured interviews were performed with a few Swedish teachers with experience from tackling different physical settings when teaching mathematics. When analysing the interview transcripts preliminary findings are that: teachers appreciate flexibility and control over the physical settings in the classroom; inadequate acoustics are extra problematic in mathematical activities involving verbal interactions between students in small groups; mathematics task solving in peace and quiet is a common part of mathematics lessons and it easily gets disturbed by external noise.

  • 23.
    Fahlström, Magnus
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Sumpter, Lovisa
    Stockholm University.
    A model for the role of the physical environment in mathematics education2018In: Nordisk matematikkdidaktikk, ISSN 1104-2176, Vol. 3, no 1Article in journal (Refereed)
    Abstract [en]

    In this paper, we develop an analytical tool for the role of the physical environment in mathematics education. We do this by extending the didactical triangle with the physical environment as a fourth actor and test it in a review of literature concerning the physical environment and mathematics education. We find that one role played by the physical environment, in relation to mathematical content, is to portray the content in focus, such as geometry and scale. When focusing on teachers, students, and the interaction between them, the role of the physical environment appears to be a precondition, either positive (enabling) or negative (hindering). Many of the findings are valid for education in general as well, such as the importance of building status.

  • 24.
    Fahlström, Magnus
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Teledahl, Anna
    Dalarna University, School of Education, Health and Social Studies, Mathematics Education.
    Students’ use of images for documenting their problem solving2017Conference paper (Other academic)
  • 25.
    Ferreira Uchoa, Marina
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Detecting Fake Reviews with Machine Learning2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Many individuals and businesses make decisions based on freely and easily accessible online reviews. This provides incentives for the dissemination of fake reviews, which aim to deceive the reader into having undeserved positive or negative opinions about an establishment or service. With that in mind, this work proposes machine learning applications to detect fake online reviews from hotel, restaurant and doctor domains. In order to _lter these deceptive reviews, Neural Networks and Support Vector Ma- chines are used. Both algorithms' parameters are optimized during training. Parameters that result in the highest accuracy for each data and feature set combination are selected for testing. As input features for both machine learning applications, unigrams, bigrams and the combination of both are used. The advantage of the proposed approach is that the models are simple yet yield results comparable with those found in the literature using more complex models. The highest accuracy achieved was with Support Vector Machine using the Laplacian kernel which obtained an accuracy of 82.92% for hotel, 80.83% for restaurant and 73.33% for doctor reviews.

  • 26.
    Golkhari Baghini, Amir
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Daily individuals’ accessibility to other individuals and the impact of changes in intra-travel time on changes in daily accessibility in Sweden2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The overall aim of this study is to understand how average daily individuals’ accessibility to other individuals has changed in Sweden and what the impact of changes in intra-travel time is on changes in daily individuals’ accessibility in Dalarna County.

    This thesis was conducted by applying quantitative research method via secondary data collection method. The required data for the purpose of this study were collected from Official Statistic of Sweden (SCB), Swedish Road Administration (NVDB) and Swedish National Travel Survey (RVU). Research population or target population for this study is all Swedish workforce population, aged 20-64. For the first part of the aim, the entire research population has been investigated and for the second part of the aim, non-probability sampling method (purposive sampling method) has been applied. The datasets have been applied to compute different variables. The variables were computed by using formulas extracted from previous empirical studies and with help of GIS and R software. The relationship between response and predictors variables has been statistically analyzed by multiple linear regression.

    The findings indicate that average daily individuals’ accessibility increased within the Swedish context between the years 1990 and 2008. It was found that the most increment was related to years 1995 to 2000. Also the statistical analysis showed that the relationship between the changes in average intra-travel time and changes in average daily individuals’ accessibility was not significant in municipalities in Dalarna County. Meanwhile, it was concluded that among predictor variables, changes in average daily mobility had a significant relationship with the changes in average daily individuals’ accessibility to other individuals within municipalities in Dalarna County.

  • 27.
    Grek, Åsa
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Nonresponse issues when analysing business survey data2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Data issues due to nonresponse or missing data arises often in company surveys or in firm data. Missing data and nonresponse causes bias. Another problem that causes bias is omitted variables. Accordingly, it will lead to wrong conclusions. The idea behind this licentiate thesis is to address these problems. The aim is to develop an insight into how common problems can be solved by transforming the data and changing the statistical method. There is no claim that the method suggested in the papers is always optimal. Rather, the goal of the papers is to give an awareness of problems that occurs in quantitative business research.

  • 28.
    Grek, Åsa
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Growing profitable or growing from profits: A commentManuscript (preprint) (Other academic)
  • 29.
    Grek, Åsa
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Auxiliary variables for nonresponse adjustment in business surveysManuscript (preprint) (Other academic)
  • 30.
    Grek, Åsa
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Determinants of debt leverage ratios in Swedish listed companiesManuscript (preprint) (Other academic)
  • 31. Gu, Yaxiu
    et al.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Chen, Xiangjie
    Yuan, Yanping
    Techno-economic analysis of a solar photovoltaic/thermal (PV/T) concentrator for building application in Sweden using Monte Carlo method2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 165, p. 8-24Article in journal (Refereed)
    Abstract [en]

    The solar energy share in Sweden will grow up significantly in next a few decades. Such transition offers not only great opportunity but also uncertainties for the emerging solar photovoltaic/thermal (PV/T) technologies. This paper therefore aims to conduct a techno-economic evaluation of a reference solar PV/T concentrator in Sweden for building application. An analytical model is developed based on the combinations of Monte Carlo simulation techniques and multi energy-balance/financial equations, which takes into account of the integrated uncertainties and risks of various variables. In the model, 11 essential input variables, i.e. average daily solar irradiance, electrical/thermal efficiency, prices of electricity/heating, operation &amp; management (OM) cost, PV/T capital cost, debt to equity ratio, interest rate, discount rate, and inflation rate, are considered, while the economic evaluation metrics, such as levelized cost of energy (LCOE), net present value (NPV), and payback period (PP), are primarily assessed. According to the analytical results, the mean values of LCOE, NPV and PP of the reference PV/T connector are observed at 1.27 SEK/kW h (0.127 €/kW h), 18,812.55 SEK (1881.255 €) and 10 years during its 25 years lifespan, given the project size at 10.37 m2 and capital cost at 4482–5378 SEK/m2 (448.2–537.8 €/m2). The positive NPV indicates that the investment on the selected PV/T concentrator will be profitable as the projected earnings exceeds the anticipated costs, depending on the NPV decision rule. The sensitivity analysis and the parametric study illustrate that the economic performance of the reference PV/T concentrator in Sweden is mostly proportional to solar irradiance, debt to equity ratio and heating price, but disproportionate to capital cost and discount rate. Together with additional market analysis of PV/T technologies in Sweden, it is expected that this paper could clarify the economic situation of PV/T technologies in Sweden and provide a useful model for their further investment decisions, in order to achieve sustainable and low-carbon economics, with an expanded quantitative discussion of the real economic or policy scenarios that may lead to those outcomes.

  • 32.
    Guo, Shengqiang
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Computation and application of the spatial zero inflated count response2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Generalized linear models and its extensions are widely used for analyzing non-normal data. But Poisson mixed model may exhibit inadequate fitting and inference when encounter excessive zero counts. Mixed hurdle model is a preferable method to solve the problem. Nevertheless, it is still a challenge to use the mixed hurdle model to deal with correlated data. There are a few computational procedure for hurdle model can be used to calculate, particularly for the model with random effects being correlated between non-zero and zero response parts. In our paper we display a method to fit the hurdle model with conditionally autoregressive random effects for the spatial data. Based on the extended algorithm, some modifications are made to the existing procedure in R to help us to fit the data. We conduct Monte-Carlo simulation to study the finite sample properties of our model. The result shows that the new procedure fit the model well. The estimation becomes better with the increase of measurement in each subject. At last, we apply the new procedure to a real problem. The dataset is about reindeer spatial distribution related to the wind power establishments at Storliden Mountain in North Sweden. The new procedure gives a better fit of the real problem than a usual Poisson mixed model

  • 33.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Mihaescu, Oana
    HUI Research, Sweden.
    Li, Yujiao
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics. HUI Research, Sweden.
    Comparison and one-stop shopping after big-box retail entry: a spatial difference-in-difference analysis2018In: Journal of Retailing and Consumer Services, ISSN 0969-6989, E-ISSN 1873-1384, Vol. 40, p. 175-187Article in journal (Refereed)
    Abstract [en]

    This paper empirically measures the potential spillover effects of big-box retail entry on the productivity of incumbent retailers in the entry regions, and investigates whether the effects differ depending on 1) if the entry is in a rural or urban area, and 2) if the incumbent retailers are within retail industries selling substitute or complement goods to those found in IKEA. To identify the IKEA-entry effect, a difference-in-difference model is suitable, but traditionally such estimators neglect the possibility that firms’ sales are determined by a process with spatially interactive responses. If ignored, these responses may cause biased estimates of the IKEA entry effect due to spatial heterogeneity of the treatment effect. One objective of this paper is thus to propose a spatial difference-in-difference estimator accounting for possible spatial spillover effects of IKEA entry. Particular emphasis is placed on the development of a suitable weight matrix accounting for the spatial links between firms, where we allow for local spatial interactions such that the outcome of observed units depends both on their own treatment as well as on the treatment of their neighbors. Our results show that for complementary goods retailers (or one-stop shopping retailers) in Haparanda and Kalmar, productivity increased by 35% and 18%, respectively, due to IKEA entry. No statistically significant effects were found for the entries in Karlstad and Gothenburg, indicating that it is mainly incumbents in smaller entry regions that benefit from IKEA entry. Also, for incumbent retailers selling substitute (or comparison shopping) goods no significant effects were found in any of the entry regions, indicating that it is mainly retailers selling complementary goods that benefit from IKEA entry. Finally, our results also show that ignoring the possibility of spatially correlated treatment effects in the regression models reduces the estimated impact of the IKEA entries in Haparanda and Kalmar on productivity in one-stop shopping retail firms with 3% and 0.1% points, respectively. © 2017 Elsevier Ltd

  • 34.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Xu, Liguo
    May, Ross
    Pan, Song
    Wu, Jinshun
    A review of reinforcement learning methodologies on control systems for building energy2018Report (Other academic)
    Abstract [en]

    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.

  • 35.
    Hozzánková, Hana
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Modelling S shaped hazard function: A case of evaluating Volvo Cars training project2014Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study is to introduce a new S-shaped hazard function, derive its corre-

    sponding likelihood function and then apply it to a real dataset to show advantages of

    such method. We dened an inovative S-shaped hazard function based on arctangent

    with three additional parameters. Our hazard function opens new possibilities for the

    measurement of the lock-in e ect directly using one of its parameters. Its signicance is

    further tested by a standard Wald test. We derive a log-likelihood function and apply

    it on a data from Volvo Cars Project. According to our results we conclude that the

    program was unsuccessful. Surprising shapes of nal hazard functions lead us to closer

    examination of possible limitations. We conclude that our results could be a ected

    by several aspects such as data quality, computational methods and possible violation

    of independency assumption. Nevertheless, this study works as a useful summary of

    the newly-dened S-shaped hazard function and highlights its innovative possibility to

    estimate lock-in e ect together with its signicance testing.

  • 36.
    Huq, Asif
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    How does accounting and auditing regulations affect firm growth and cost of capital?2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis provides an understanding of how new audit regulation affect firm growth and how audits affect the cost of capital. To investigate the effect of audit reforms on employment growth, we exploited a Swedish reform made in November 2010 that gave certain firms the option to opt out of previously imposed statutory audits. We find that firms which fulfilled the requirements for voluntary auditing, compared to a control group of similar firms that did not, increased their employment growth rate by 0.39%. Furthermore, the reform was also exploited to investigate if audited financial statements add value for firms in the private debt market. We find that firms with audited financial statements, on average, save 1.26 percentage points on cost of debt compared to firms with unaudited financial statements. Thus, the reform creates a possibility for firms that have the ambition to grow in employment to do so by not auditing, and those who want to grow by investments in capital to do so by reducing the cost of such investments by auditing. However, the current ceiling of the reform is also likely to force some firms to operate at sub-optimal levels, those without having the option to opt out of audit even though they might not accrue any benefit from auditing, at least in the short-run. One can argue that is partly due to how institutions evolve, generally slower than other actors in the society do.

  • 37.
    Huq, Asif
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Daunfeldt, Sven-Olov
    Dalarna University, School of Technology and Business Studies, Economics.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management. Högskolan i Gävle.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics.
    Does voluntary audit increase small firm growth?: Evidence from a natural experiment2017In: EAA 2017 Abstracts, 2017Conference paper (Refereed)
    Abstract [en]

    Many European countries have abolished mandatory audits for small firms, but we still lack knowledge on whether this affects small firm growth. A Swedish reform in 2010 made audits voluntary for small firms fulfilling certain requirements, while firms that did not meet these requirements still had mandatory audits. We argue that this regulatory change created an almost perfect natural experiment, which can be exploited to evaluate the effects of the reform on employment growth using a difference-in-difference estimator. Our results show that firms who fulfil the requirements for voluntary auditing, as compared to a control group of firms that does not, increased their employment growth rates by on average 0.39%, corresponding to 5 500 jobs being created in the three years following the reform. It thus seems that voluntary audits are reducing the regulatory burden for small firms, making resources available that can be used to increase the number of employees. The current threshold levels for mandatory audits are still significantly lower in Sweden than in most other European countries, which implies that the policymakers in Sweden could create more jobs in small and medium-sized firms if they increased the size threshold levels for mandatory audits.

  • 38.
    Huq, Asif
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Daunfeldt, Sven-Olov
    Dalarna University, School of Technology and Business Studies, Economics. HUI Research.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management. Högskolan i Gävle.
    Rudholm, Niklas
    HUI Research.
    Free to choose: Do voluntary audit reforms increase employment growth?2018Report (Refereed)
    Abstract [en]

    Many European countries have abolished mandatory audits for small firms to reduce the regulatory and administrative burden for these firms. However, we still lack knowledge on whether such legislative changes affect employment growth for those firms that become free to choose to have external audits. We investigate this question using a Swedish reform that made audits voluntary for small firms fulfilling certain requirements. The reform created an almost ideal natural experiment, which we use to evaluate the effects of voluntary audits on employment growth for small firms using a difference-in-difference estimator. We find that firms which fulfilled the requirements for voluntary auditing, compared to a control group of similar firms that did not, increased their employment growth rate by 0.39%. This corresponds to 1,830 jobs being created in the year following the reform, suggesting that mandatory audits act as a growth barrier for small firms.

  • 39.
    Huq, Asif
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Daunfeldt, Sven-Olov
    Dalarna University, School of Technology and Business Studies, Economics.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Rudholm, Niklas
    Dalarna University, School of Technology and Business Studies, Economics.
    The effect of audit reform on the employment growth of small Swedish limited companies: A natural experiment2017Conference paper (Refereed)
    Abstract [en]

    Reducing the regulatory burden for firms will free resources that can be used for productive investments. In this paper, we investigate the effect of a change in regulations, in effect abolishing statutory audits for Swedish micro firms in November 2010, on employment growth in the affected micro firms. The changes in regulations created what we argue is an almost perfect natural experiment that can be exploited to evaluate the effects of the reform on employment growth using a difference-in-difference estimator. Our results show that employment growth is higher in firms which fulfil the requirements for voluntary auditing as compared to a control group of firms of similar sizes that does not, and the positive treatment effect is found for micro firms in all Swedish counties and in all types of industries. We estimate that the reform created 1276 jobs in the three years following the reform. We thus suggest that the current threshold for statutory audits should be increased in Sweden, whose threshold levels for statutory audits are significantly lower than in most other European countries even after the 2010 changes in regulations. Such a regulatory change would, in all likelihood, lead to employment growth in the affected firms. 

  • 40.
    Huq, Asif
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management. Högskolan i Gävle.
    Rudholm, Niklas
    Handelns utredningsinstitut.
    Do Audited Firms Have Lower Cost of Debt?2018Conference paper (Refereed)
  • 41.
    Huq, Asif
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Hartwig, Fredrik
    Dalarna University, School of Technology and Business Studies, Business Administration and Management. Högskolan i Gävle.
    Rudholm, Niklas
    HUI Research.
    Do audited firms have lower cost of debt?2018Report (Other academic)
    Abstract [en]

    The purpose of this study is to investigate if audited financial statements add value for firms in the private debt market. Using an instrumental variable method, we find that firms with audited financial statements, on average, save 1.26 percentage points on cost of debt compared to firms with unaudited financial statements. We also find that using the big, well-known auditing firms does not yield additional cost of debt benefits. Lastly, we find that the effect of audit on cost of debt varies between industries. As such, we find that firms in industries that have been identified in previous studies to have a more complex information structure, and therefore more complex auditing process, also save more on cost of debt relative to other industries when audited.

  • 42.
    Håkansson, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Lagin, Madelen
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Wennström, Johanna
    Town centre cooperation: Changing perception of property owners2017In: International Journal of Retail & Distribution Management, ISSN 0959-0552, E-ISSN 1758-6690, Vol. 45, no 11, p. 1200-1212Article in journal (Refereed)
    Abstract [en]

    Purpose – The purpose of this paper is to investigate if, and how, different stakeholders perceive property owners (PO) have changed their activities in a town centre after increased competition, and if this has led to a different perception of the PO' stakeholder group. Design/methodology/approach – A comparative follow-up case study is conducted through semi-structured interviews on changes in the town centre management (TCM) stakeholders' perceptions of the role, benefit, and contribution of PO. The interviews are carried out before and after the establishment of a big-box retailer, which makes it possible to analyse possible changes in the perceptions in relation to the overall role of the PO when retail competition increases. Findings – A limited number of PO and local authorities have started working more strategically and proactively by creating a time-restricted alliance that goes beyond the work of the TCM organisation. Although the activities of the PO have increased, this is not fully understood by everyone in the town centre, especially the retailers. Research limitations/implications – In comparison with other studies, this study clearly indicates that the property owner plays a key strategic role in enabling town centre development. This role is broader than what the original TCM literature suggests and is based on the aspects of resource coordination and distribution. Practical implications – In order to create the opportunity to develop a town centre in the long run, it is of strategic importance that the PO are in agreement with the development plans. In addition, it is necessary to consider those members who should be part of the strategic alliance. Originality/value – By conducting a comparative follow-up case study, the authors are able to contribute with a deeper understanding of how stakeholders' perceptions change over time. The authors extend the current literature by showing that the PO are a key stakeholder due to their organisational resources and their ability to facilitate town centre development. © 2017 Emerald Publishing Limited.

  • 43.
    Håkansson, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Li, Yujiao
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Mihaescu, Oana
    HUI Research, Stockholm.
    Rudholm, Niklas
    HUI Research, Stockholm.
    Big-box retail entry in urban and rural areas: Are there productivity spillovers to incumbent retailers?Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper empirically measures the potential spillover effects of big-box retail entry on the productivity of incumbent retailers in the entry regions, and investigates whether the effects differ depending on the size of the new establishment relative to the size of the local market. The results indicate that big-box entry increases the productivity of incumbent firms in two of three rural entry regions where the IKEA is large relative to the local retail market, while no productivity spillover effects could be found in the case of the urban IKEA entry in Gothenburg.

  • 44.
    Iasonidou, Sofia
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Estimating the effect of the 2008 financial crisis on GNI in Greece and Iceland: A synthetic control approach2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to conduct a comparative study in order to estimate the impact of the financial crisis to the GNI of Greece and Iceland. By applying synthetic control matching (a relatively new methodology) the study intends to compare the two countries, thus deducting conclusions about good or bad measures adopted. The results indicate that in both cases the adopted measures were not the optimal ones, since the synthetic counterfactual appear to perform better than the actual Greece and Iceland. Moreover, it is shown that Iceland reacted better to the shock it was exposed. However, different characteristics of the two countries impede the application of Icelandic actions in the Greek case.

  • 45.
    Jia, Siqi
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    How fair is the so called fair method for resetting the targetin the interrupted men’s one-day international cricket matches?2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Duckworth-Lewis (DL) method is used in the One Day International (ODI) cricketmatches when the matches are interrupted. However, all information we have about thismethod is the Duckworth-Lewis calculator, which leads us to suspect the fairness of it.This thesis quantified the effect of the DL method on the result of the matches, whichmeans if teams have the same winning chance under DL method or not. The effect oflikely influential factors, including the use of DL method, on the winning odds areestimated by using the Generalized Linear Mixed Model. The results indicates that theDL method does not have any significant effect on the winning odds, nor does the DLmethod change the effects of other factors. The results also confirm that homeadvantage exists and that winning the coin toss does not affect the outcome of match.

  • 46. Johansson, D.
    et al.
    Ericsson, A.
    Johansson, A.
    Medvedev, A.
    Nyholm, D.
    Ohlsson, F.
    Senek, M.
    Spira, J.
    Thomas, Ilias
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Westin, Jerker
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Individualization of levodopa treatment using a microtablet dispenser and ambulatory accelerometry2018In: CNS Neuroscience & Therapeutics, ISSN 1755-5930, E-ISSN 1755-5949, Vol. 24, no 5, p. 439-447Article in journal (Refereed)
    Abstract [en]

    Aim

    This 4‐week open‐label observational study describes the effect of introducing a microtablet dose dispenser and adjusting doses based on objective free‐living motor symptom monitoring in individuals with Parkinson's disease (PD).

    Methods

    Twenty‐eight outpatients with PD on stable levodopa treatment with dose intervals of ≤4 hour had their daytime doses of levodopa replaced with levodopa/carbidopa microtablets, 5/1.25 mg (LC‐5) delivered from a dose dispenser device with programmable reminders. After 2 weeks, doses were adjusted based on ambulatory accelerometry and clinical monitoring.

    Results

    Twenty‐four participants completed the study per protocol. The daily levodopa dose was increased by 15% (112 mg, < 0.001) from period 1 to 2, and the dose interval was reduced by 12% (22 minutes, P = 0.003). The treatment adherence to LC‐5 was high in both periods. The MDS‐UPDRS parts II and III, disease‐specific quality of life (PDQ‐8), wearing‐off symptoms (WOQ‐19), and nonmotor symptoms (NMS Quest) improved after dose titration, but the generic quality‐of‐life measure EQ‐5D‐5L did not. Blinded expert evaluation of accelerometry results demonstrated improvement in 60% of subjects and worsening in 25%.

    Conclusions

    The introduction of a levodopa microtablet dispenser and accelerometry aided dose adjustments improve PD symptoms and quality of life in the short term.

  • 47.
    Jomaa, Diala
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Yella, Siril
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Automatic trigger speed for vehicle activated signs using Adaptive Neuro fuzzy system and Random ForestIn: International Journal on Advances in Intelligent Systems, ISSN 1942-2679, E-ISSN 1942-2679Article in journal (Refereed)
  • 48.
    Jomaa, Diala
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Yella, Siril
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Predicting automatic trigger speed for vehicle-activated signs2018In: Journal of Intelligent Systems, ISSN 0334-1860, E-ISSN 2191-026XArticle in journal (Refereed)
    Abstract [en]

    Vehicle-activated signs (VAS) are speed-warning signs activated by radar when the driver speed exceeds a pre-set threshold, i.e. the trigger speed. The trigger speed is often set relative to the speed limit and is displayed for all types of vehicles. It is our opinion that having a static setting for the trigger speed may be inappropriate, given that traffic and road conditions are dynamic in nature. Further, different vehicle classes (mainly cars and trucks) behave differently, so a uniform trigger speed of such signs may be inappropriate to warn different types of vehicles. The current study aims to investigate an automatic VAS, i.e. one that could warn vehicle users with an appropriate trigger speed by taking into account vehicle types and road conditions. We therefore investigated different vehicle classes, their speeds, and the time of day to be able to conclude whether different trigger speeds of VAS are essential or not. The current study is entirely data driven; data are initially presented to a self-organising map (SOM) to be able to partition the data into different clusters, i.e. vehicle classes. Speed, time of day, and length of vehicle were supplied as inputs to the SOM. Further, the 85th percentile speed for the next hour is predicted using appropriate prediction models. Adaptive neuro-fuzzy inference systems and random forest (RF) were chosen for speed prediction; the mean speed, traffic flow, and standard deviation of vehicle speeds were supplied as inputs for the prediction models. The results achieved in this work show that RF is a reliable model in terms of accuracy and efficiency, and can be used in finding appropriate trigger speeds for an automatic VAS. 

  • 49.
    Jomaa, Diala
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Yella, Siril
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    A comparative study between vehicle activated signs and speed indicator devices2017In: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 22, p. 115-123Article in journal (Refereed)
    Abstract [en]

    Vehicle activated signs and Speed indicator devices are safety signs used to warn and remind drivers that they are exceeding the speed limit on a particular road segment. This article has analysed and compared such signs with the aim of reporting the most suitable sign for relevant situations. Vehicle speeds were recorded at different test sites and the effects of the signs were studied by analyzing the mean and standard deviation. Preliminary results from the work indicate that both types of signs have variable effects on the mean and standard deviation of speed on a given road segment. Speed indicator devices were relatively more effective than vehicle activated signs on local roads; in contrast their effectivity was only comparable when tested on highways.

  • 50.
    Kogo, Gloria
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Analyzing automatic cow recordings to detect the presence of outliers in feed intake data recorded from dairy cows in Lovsta farm2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Outliers are a major concern in data quality as it limits the reliability of any data. The

    objective of our investigation was to examine the presence and cause of outliers in the system

    for controlling and recording the feed intake of dairy cows in Lovsta farm, Uppsala Sweden.

    The analyses were made on data recorded as a timestamp of each visit of the cows to

    the feeding troughs from the period of August 2015 to January 2016. A three step

    methodology was applied to this data. The first step was fitting a mixed model to the

    data then the resulting residuals was used in the second step to fit a model based

    clustering for Gaussian mixture distribution which resulted in clusters of which 2.5% of

    the observations were in the outlier cluster. Finally, as the third step, a logistic

    regression was then fit modelling the presence of outliers versus the non-outlier

    clusters. It appeared that on early hours of the morning between 6am to 11.59am, there

    is a high possibility of recorded values to be outliers with odds ratio of 1.1227 and this

    is also the same time frame noted to have the least activity in feed consumption of the

    cows with a decrease of 0.027 kilograms as compared to the other timeframes. These

    findings provide a basis for further investigation to more specifically narrow down the

    causes of the outliers.

12 1 - 50 of 94
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf