Vehicle safety and road safety are two important issues. They are related to each other and road accidents are mostly caused by driver distraction. Issues related to driver distraction like eating, drinking, talking to a passenger, using IVIS (In-Vehicle Information System) and thinking something unrelated to driving are some of the main reasons for road accidents. Driver distraction can be categorized into 3 different types: visual distraction, manual distraction and cognitive distraction. Visual distraction is when driver's eyes are off the road and manual distraction is when the driver takes one or both hands off the steering wheel and places the hand/s on something that is not related to the driving safety. Cognitive distraction whereas happens when a driver's mind is not on the road. It has been found that cognitive distraction is the most dangerous among the three because the thinking process can induce a driver to view and/or handle something unrelated to the safety information while driving a vehicle. This study proposes a physiological measurement to detect driver cognitive distraction. Features like lips, eyebrows, mouth movement, eye movement, gaze rotation, head rotation and blinking frequency are used for the purpose. Three different sets of experiments were conducted. The first experiment was conducted in a lab with faceLAB cameras and served as a pilot study to determine the correlation between mouth movement and eye movement during cognitive distraction. The second experiment was conducted in a real traffic environment using faceAPI cameras to detect movement on lips and eyebrows. The third experiment was also conducted in a real traffic environment. However, both faceLAB and faceAPI toolkits were combined to capture more features. A reliable and stable classification algorithm called Dynamic Bayesian Network (DBN) was used as the main algorithm for analysis. A few more others algorithms like Support Vector Machine (SVM), Logistic Regression (LR), AdaBoost and Static Bayesian Network (SBN) were also used for comparison. Results showed that DBN is the best algorithm for driver cognitive distraction detection. Finally a comparison was also made to evaluate results from this study and those by other researchers. Experimental results showed that lips and eyebrows used in this study are strongly correlated and have a significant role in improving cognitive distraction detection.

<p>The aim is to share experience gained when simulating (and doing measurements on) the turbocharged SI-engine as well as describing the limits of current state of the technology. In addition an overview of current boosting systems is provided.</p><p>The target readers of this text are engineers employed in the engine industry as well as academia who will get in contact, or is experienced, with 1D engine performance simulation and/or boosting systems. Therefore the text requires general knowledge about engines.</p><p>The papers included in the thesis are, in reverse chronological order:</p><p>[8] SAE 2005-XX-XXX Calculation accuracy of pulsating flow through the turbine of SI-engine turbochargers - Part 2 Measurements, simulation correlations and conclusions Westin & Ångström</p><p>To be submitted to the 2005 SAE Powertrain and Fluid Systems Conference in San Antonio</p><p>[7] SAE 2005-01-2113 Optimization of Turbocharged Engines’ Transient Response with Application on a Formula SAE / Student engine Westin & Ångström</p><p>Approved for publication at the 2005 SAE Spring Fuels and Lubricants Meeting in Rio de Janeiro</p><p>[6] SAE 2005-01-0222 Calculation accuracy of pulsating flow through the turbine of SI-engine turbochargers - Part 1 Calculations for choice of turbines with different flow characteristics Westin & Ångström</p><p>Published at the 2005 SAE World Congress in Detroit April 11-14, 2005</p><p>[5] SAE 2004-01-0996 Heat Losses from the Turbine of a Turbocharged SI-Engine – Measurements and Simulation Westin, Rosenqvist & Ångström</p><p>Presented at the 2004 SAE World Congress in Detroit March 8-11, 2004</p><p>[4] SAE 2003-01-3124 Simulation of a turbocharged SI-engine with two software and comparison with measured data Westin & Ångström</p><p>Presented at the 2003 SAE Powertrain and Fluid Systems Conference in Pittsburgh</p><p>[3] SIA C06 Correlation between engine simulations and measured data - experiences gained with 1D-simulations of turbocharged SI-engines Westin, Elmqvist & Ångström</p><p>Presented at the SIA International Congress SIMULATION, as essential tool for risk management in industrial product development in Poissy, Paris September 17-18 2003</p><p>[2] IMechE C602/029/2002 A method of investigating the on-engine turbine efficiency combining experiments and modelling Westin & Ångström</p><p>Presented at the 7th International Conference on Turbochargers and Turbocharging in London 14-15 May, 2002</p><p>[1] SAE 2000-01-2840 The Influence of Residual Gases on Knock in Turbocharged SI-Engines Westin, Grandin & Ångström</p><p>Presented at the SAE International Fall Fuels and Lubricants Meeting in Baltimore October 16-19, 2000</p><p>The first step in the investigation about the simulation accuracy was to model the engine as accurately as possible and to correlate it against as accurate measurements as possible. That work is covered in the chapters 3 and 5 and in paper no. 3 in the list above. The scientific contribution here is to isolate the main inaccuracy to the simulation of turbine efficiency.</p><p>In order to have anything to compare the simulated turbine efficiency against, a method was developed that enables calculation of the CA-resolved on-engine turbine efficiency from measured data, with a little support from a few simulated properties. That work was published in papers 2 and 8 and is the main scope of chapter 6 in the thesis. The scientific contributions here are several:</p><p>· The application on a running SI-engine is a first</p><p>· It was proven that CA-resolution is absolutely necessary in order to have a physically and mathematically valid expression for the turbine efficiency. A new definition of the time-varying efficiency is developed.</p><p>· It tests an approach to cover possible mass accumulation in the turbine housing</p><p>· It reveals that the common method for incorporating bearing losses, a constant mechanical efficiency, is too crude.</p><p>The next step was to investigate if different commercial codes differ in the results, even though they use equal theoretical foundation. That work is presented in chapter 4, which corresponds to paper 4. This work has given useful input to the industry in the process of choosing simulation tools.</p><p>The next theory to test was if heat losses were a major reason for the simulation accuracy. The scientific contribution in this part of the work was a model for the heat transport within the turbocharger that was developed, calibrated and incorporated in the simulations. It was concluded that heat losses only contributed to a minor part of the inaccuracy, but that is was a major reason for a common simulation error of the turbine outlet temperature, which is very important when trying to simulate catalyst light off. This work was published in paper 5 and is covered in chapter 7.</p><p>Chapter 8, and papers 6 and 8, covers the last investigation of this work. It is a broad study where the impact of design changes of both manifold at turbines on both simulation accuracy as well as engine performance. The scientific contribution here is that the common theory that the simulation inaccuracy is proportional to the pulsation amplitude of the flow is non-valid. It was shown that the reaction was of minor importance for the efficiency of the turbine in the pulsating engine environment. Furthermore it presents a method to calculate internal flow properties in the turbine, by use of a steady-flow design software in a quasi-steady procedure. Of more direct use for the industry is important information of how to design the manifolds as well as it sheds more light on how the turbine works under unsteady flow, for instance that the throat area is the single most important property of the turbine and that the system has a far larger sensitivity to this parameter than to any other design parameters of the turbine. Furthermore it was proven that the variation among individual turbines is of minor importance, and that the simulation error was of similar magnitude for different turbine manufacturers.</p><p>Paper 7, and chapter 9, cover a simulation exercise where the transient performance of turbocharged engines is optimised with help from factorials. It sorts out the relative importance of several design parameters of turbocharged engines and gives the industry important information of where to put the majority of the work in order to maximize the efficiency in the optimisation process.</p><p>Overall, the work presented in this thesis has established a method for calibration of models to measured data in a sequence that makes the process efficient and accurate. It has been shown that use of controllers in this process can save time and effort tenfold or more.</p><p>When designing turbocharged engines the residual gas is a very important factor. It affects both knock sensitivity and the volumetric efficiency. The flow in the cylinder is in its nature of more dimensions than one and is therefore not physically modelled in 1D codes. It is modelled through models of perfect mixing or perfect displacement, or at a certain mix between them. Before the actual project started, the amount of residual gases in an engine was measured and it’s influence on knock was established and quantified. This was the scope of paper 1. This information has been useful when interpreting the model results throughout the entire work.</p>

<p>In this paper, the forecast performance of an unrestricted Vector Autoregressive (VAR) model was compared against the forecast accuracy of a Vector error correction (VECM) model when computing out-of-sample forecasts for Swedish exports. The co-integrating relation used to estimate the error correction specification was based upon an economic theory for international trade suggesting that a long run equilibrium relation among the variables included in an export demand equation should exist. The results obtained provide evidence of a long run equilibrium relationship between the Swedish export volume and its main determinants. The models were estimated for manufactured goods using quarterly data for the period 1975-1999 and once estimated, the models were used to compute out-of-sample forecasts up to four-, eight- and twelve-quarters ahead for the Swedish export volume using both multi-step and one-step ahead forecast techniques. The main results suggest that the differences in forecasting ability between the two models are small, however according to the relevant evaluation criteria the unrestricted VAR model in general yields somewhat better forecast than the VECM model when forecasting Swedish exports over the chosen forecast horizons.</p>

Drawing upon the writing literature and the task-based language teaching literature, the study examined two cognitive complexity dimensions of L2 writing tasks: rhetorical task varying in reasoning demand and topic familiarity varying in the amount of direct knowledge of topics. Four rhetorical tasks were studied: narrative, expository, expo-argumentative, and argumentative tasks. Three topic familiarity tasks were investigated: personal-familiar, impersonal-familiar, and impersonal-less familiar tasks. Specifically, the study looked into the effects of these two cognitive complexity dimensions on L2 writing quality scores, their effects on complexity, accuracy, and fluency (CAF) of L2 production, and the predictive power of the CAF features on L2 writing scores for each task. Three hundred and seventy five Chinese university EFL students participated in the study, and each student wrote on one of the six writing tasks used to study the cognitive complexity dimensions. The essays were rated by trained raters using a holistic scale. Thirteen CAF measures were used, and the measures were all automated through computer tools. One-way ANOVA tests revealed that neither rhetorical task nor topic familiarity had an effect on the L2 writing scores. One-way MANOVA tests showed that neither rhetorical task nor topic familiarity had an effect on accuracy and fluency of the L2 writing, but that the argumentative essays were significantly more complex in global syntactic complexity features than the essays on the other rhetorical tasks, and the essays on the less familiar topic were significantly less complex in lexical features than the essays on the more familiar topics. All-possible subsets regression analyses revealed that the CAF features explained approximately half of the variance in the writing scores across the tasks and that writing fluency was the most important CAF predictor for five tasks. Lexical sophistication was however the most important CAF predictor for the argumentative task. The regression analyses further showed that the best regression models for the narrative task were distinct from the ones for the expository and argumentative types of tasks, and the best models for the personal-familiar task were distinct from the ones for the impersonal tasks.

Nombreuses sont les situations où notre mémoire nous fait défaut. A qui n’est-il jamais arrivé de se retrouver face à une personne sans se rappeler son prénom ? Pourtant vous savez que vous connaissez ce visage et que vous êtes même capables de resituer la dernière fois où vous l’avez déjà vu. A l’inverse, vous pouvez être sûr d’avoir déjà rencontré une personne alors que c’est la première fois que vous la voyez… Pour autant, dans ces deux situations, vous n’avez jamais oublié ce qu’était un visage. Tout en étant faillible dans certaines situations, l’efficacité de notre mémoire reste bien souvent inaperçue. Cette thèse propose de traiter la question de l’efficacité mnésique dans une modélisation particulière de la mémoire : les modèles à traces multiples. Nous traiterons de l’apport de cette notion à l’approche développée par Versace et collaborateurs (2002 ; 2009). Cette dernière suppose que les connaissances émergent d’un système unique de mémoire à partir de l’activation et de l’intégration de traces mnésiques épisodiques multimodales et distribuées.Suivant cette approche, il apparaît que l’efficacité dans les activités catégorielles s’explique par une relation de similarité entre un indice à traiter et un grand nombre de traces en mémoire, alors que l’efficacité dans les tâches discriminantes implique que l’indice à traiter active non seulement une quantité restreinte de traces mais surtout que celles-ci soient suffisamment intégrées. L’étude de l’efficacité nous a permis de mettre en évidence deux types d’intégration : une intégration qui participe directement à l’émergence des connaissances (à la conscience), et une intégration qui participe au maintien des propriétés de l’expérience perceptive et motrice au sein d’une trace. De plus, il semblerait que, quel que soit le traitement, l’efficacité dépend de ce que l’indice active à la fois des propriétés au sein et entre les traces.A l’issue de cette thèse, nous sommes arrivés à la conclusion que l’efficacité mnésique dépend du type de tâche, de la force du liage entre les éléments de la trace et d’une relation interactive entre l’indice à traiter et les traces en mémoire. / There are many situations where our memory fails us. Who is it ever happened to meet face to one and not remember his name? Yet you are sure that you know this face and you're even able to retrieve the last time you've seen it. Conversely, you can be sure you have already met one person while it is the first time you see it... However, in both situations, you have never forgotten what a face is. While being fallible in some situations, the memory accuracy is often overlooked. This thesis proposes to address the issue of memory accuracy in a particular model of memory: multi-traces theory. We discuss the contribution of this question to the approach developed by Versace and collaborators (2002, 2009). This implies that knowledge emerging from a single memory from the activation and integration of distributed multimodal episodic memory traces.According to this approach, it appears that the accuracy in the categorical tasks is due to a similarity relationship between a cue and a large number of memory traces. While accuracy in discriminating tasks involves that a cue activate a limited number of traces, but also these ones need to be sufficiently integrated. Studying accuracy has allowed us to identify two kinds of integration: integration directly involved in the emergence of the knowledge (to the consciousness), and integration which ensures that former perceptivo-motor experience is encoded within a trace. Moreover, it seems that each kind of processing depends on the probability that a cue activates features within and between the traces.Finally, we can say that the accuracy depends on the type of memory task, the strength of binding between the trace components, and an interactive relationship between the cue and memory traces.

Collective memory is a socially shared representation of the past. History, contrastingly, strives to be an unbiased, objective, and critical account of the past. Many researchers have argued that the so-called “history” found in school textbooks and curriculums align more with collective memory; however, many individuals do not know of the pervasiveness of collective memory in supposed “history” texts. To examine perceptions of accuracy and preference of American “history” textbook passages, individuals from Amazon’s Mechanical Turk (n= 404) participated in an online study where they were randomly assigned to read one passage that was either negatively biased, neutral, or positively biased regarding the U.S. dropping the atomic bombs over Hiroshima and Nagasaki during World War II. Participants rated their emotional valence of the event and their perceptions of accuracy and preference for the passage. The results suggest that individuals perceive negatively biased passages as less accurate and less preferable, even if their emotional valence matches the bias within the text. Individuals also showed the hypothesized interaction for preference; those who perceived the event as not negative preferred the positive text to the neutral and negative texts. The findings support evidence that individuals are motivated to prefer history passages consistent with their attitudes and rate higher accuracy among positive and neutral texts. The results have broader implications on reporting or dismissing human rights violations within collective memory.

Background Pain and dysfunction in the temporomandibular region (Temporomandibular Disorders, TMD) are common conditions in the general population with an estimated treatment need of 5-15% in the general population. However, in Sweden, traceable performed treatments are significantly lower. The reasons for this indicated under-treatment are not known. To easily detect patients with a potential TMD related condition, three screening questions, 3Q/TMD, have been introduced. The aim with this project was to evaluate the validity and outcome of the 3Q/TMD with the objective to recognize individuals with TMD and potential treatment need in the Public Dental Health service (PDHS). Methods The thesis is based on four study samples; three from the PDHS in the county of Västerbotten, Sweden and one sample from the specialized orofacial pain clinic at the Academic Centre for Dentistry, ACTA, Amsterdam, the Netherlands. The bases for all studies are individuals’ answers to the 3Q/TMD and quantitative approaches were used in the analyses. The prevalence of affirmative answers was evaluated in a large cross-sectional study over the lifespan. The validity of the 3Q/TMD in relation to the Diagnostic Criteria for TMD (DC/TMD) as reference standard was established in two case-control studies. The outcome of the 3Q/TMD on TMD treatment within general practice was evaluated in a cohort study. Results Affirmative answers to the 3Q/TMD increased during adolescence. Women answered affirmatively to the 3Q/TMD significantly more often compared to men for all age groups expect for the first and last parts of a one hundred-year lifespan. The highest prevalence was reported by women during their fertile period in life. In a general population sample, 74% of individuals with an affirmative answer qualified for a DC/TMD pain or dysfunctional diagnosis, as compared to 64% in a specialist patient sample. In the general population sample, for the individual 3Q/TMD questions, as well as combinations of questions, the negative predictive values were high (0.92-0.99). For the specialist sample, when at least one question was answered affirmatively the negative predictive value was high (0.90). The positive predictive value was high (0.89) when all three questions were positive. There was significantly more treatment performed or recommended for 3Q-positives (21.5%) compared to 3Q-negatives (2.2%) (P&lt;0.001). The odds ratio for TMD-related treatment for 3Q-positives versus 3Q-negatives was 12.1 (95% CI: 6.3-23.4). Conclusion The 3Q/TMD is a convenient and valid tool to recognize individuals who would benefit from a further TMD examination within an adult, general population. Within specialized orofacial pain clinics, the questions are useful as guidance for further diagnostics. Although the 3Q/TMD was a factor related to TMD treatment, the majority of individuals with self-reported symptoms of TMD still did not receive traceable assessment or treatment. Factors associated with dentists’ clinical decision-making in relation to TMD warrants further research. The utilization of the 3Q/TMD as a part of a decision tree for the clinician can improve the health care for patients with TMD and is therefore recommended within dentistry. / Bakgrund Smärta och funktionsstörningar i käksystemet (TMD) är vanligt förekommande och de flesta av dessa patienter kan behandlas framgångsrikt i tandvården. Tidigare studier har visat att det kan finnas en skillnad mellan det skattade vårdbehovet och utförd behandling för patienter med TMD i tandvården. Anledningen till detta är inte känt och har identifierats som en kunskapslucka av Socialstyrelsen. Den vanligaste orsaken till akut smärta i ansiktsregion är tandvärk medan kronisk smärta oftast är relaterat till smärttillstånd i muskulatur och käkled (TMD). Att leva med smärta har en negativ påverkan på livskvaliteten oavsett om smärtan är orsakad av tandvärk eller TMD. Kvinnor uppger symtom på TMD ungefär två gånger så ofta som män och förekomsten är som högst bland kvinnor i arbetsför ålder. Smärtan är ofta relaterad till stress och långvarig smärta ökar risken för såväl spridning till andra lokalisationer som till sömnbesvär och nedstämdhet. Tidig intervention har visat sig betydelsefull för att minska risken för negativa konsekvenser relaterat till kroniska besvär. Sammantaget visar detta på vikten av ett system inom tandvården för att tidigt identifiera patienter som är i möjligt behov av fördjupad utredning och eventuellt behandling. Därför har tre screeningfrågor för TMD, 3Q/TMD införts inom tandvården. I Folktandvården i Västerbotten infördes frågorna i maj 2010 som en obligatorisk del av den digitala hälsodeklarationen för samtliga patienter. Syfte Syftet med avhandlingen har varit att synliggöra patienter med smärta och käkfunktionsstörning i befolkningen och att därmed förbättra omhändertagandet av patienter med TMD inom Folktandvården. De specifika målen var att: i) beskriva förekomst av frekvent smärta och dysfunktion i ansikte, käke och käkled för män och kvinnor för olika åldersgrupper baserat på tre screeningfrågor ii) bedöma de tre screeningfrågornas validitet i förhållande till en diagnos enligt Diagnostic Criteria for TMD, DC/TMD i två olika populationer iii) utvärdera utfallet av 3Q/TMD på klinisk beslutsprocess inom Folktandvården i Västerbotten, Sverige. Studiepopulation och metod Avhandlingen baserades på fyra olika urval av patientpopulationer, tre från Folktandvården i Västerbotten, Sverige och en från Specialistkliniken från Academish Centrum Tandheelkunde Amsterdam, ACTA, Amsterdam, Nederländerna. Underlaget för samtliga studier var baserade på individuella svar på de tre screeningfrågorna. Förekomsten av de som svarat ja på någon av frågorna utvärderades i en tvärsnittsstudie bland nästan 140 000 individer och över ett helt livsspann. Validiteten för 3Q/TMD i relation till en diagnos enligt DC/TMD utvärderades i två fall-kontroll studier. Först undersöktes en studiepopulation från Folktandvården i Västerbotten, Sverige för att representera allmän befolkningen. Därefter utvärderades screeningfrågorna bland de patienter som remitterats till en specialistklinik i Amsterdam, Nederländerna på grund av TMD relaterade besvär. Dessa representerar remitterade patienter. Utfallet av 3Q/TMD på TMD behandling i Folktandvården utvärderades i en prospektiv kohort studie. Resultat Förekomsten av de som svarat ja på någon av frågorna ökar under tonåren. Kvinnor svarar ja på någon av frågorna signifikant oftare än män i alla åldrar, utom i början och slutet av livsspannet. Den högsta prevalensen noterades för kvinnor i fertil ålder. I allmänbefolkningen kvalificerar 74% av de som svarat ja på någon av frågorna även för en DC/TMD diagnos. Motsvarande siffra för urvalet från specialistkliniken var 64%. I urvalet från allmänbefolkningen var det negativa prediktiva värdet högt för såväl alla enskilda frågor som för kombinationer av frågor (0.92-0.99). Bland de remitterade patienterna, var negativt prediktivt värde högt när individen svarade ja på minst en fråga (0.90). Positivt prediktivt värde var högt när individen svarat ja på alla tre frågorna (0.89). Behandling hade utförts eller rekommenderats signifikant oftare till de som svarat ja på någon av frågorna (21.5%) jämfört med de som svarat nej på alla tre frågor (2.2%) (P&lt;0.001). Odds ratio för TMD behandling för 3Q-positiva jämfört med 3Q-negativa var 12.1 (95% CI:6.3-23.4). Slutsats Sammanfattningsvis visar resultaten att en betydande andel av befolkningen, framför allt kvinnor i arbetsför ålder, har smärta och/eller funktionsstörningar i käksystemet. Frågorna är lämpliga för att screena patienter i behov av en fördjupad utredning. De som svarat nej kommer med stor sannolikhet inte att kvalificera för en diagnos enligt DC/TMD. Bland remitterade patienter kommer majoriteten att svara ja på någon av frågorna. I allmäntandvården får två tredjedelar av det som svarat ja på minst en fråga, inte ett synliggjort omhändertagande baserat på vad som är angivet i deras tandvårdsjournal. Detta kan tyda på brister bland allmäntandläkare och tandhygienister i kliniskt beslutsfattande för patienter med TMD.

The purpose of this research is to investigate current company business process from sales forecasting perspective and provide potential improvements of how to deal with unstable market demand and increase overall precision of forecasting. The problem which company face is an unstable market demand and not enough precision in sales forecasting process. Therefore the research questions are:  How current forecasting process can be improved?  What methods, can be implemented in order to increase the precision of forecasting? Study can be described as an action research using an abductive approach supported by combination of quantitative and qualitative analysis practices. In order to achieve high degree of reliability the study was based on verified scientific literature and data collected from the case company while collaborating with company’s COO. Research exposed the current forecasting process of the case company. Different forecasting methods were chosen according to the existing circumstances and analyzed in order to figure out which could be implemented in order to increase forecasting precision and forecasting as a whole. Simple exponential smoothing showed the most promising accuracy results, which were measured by applying MAD, MSE and MAPE measurement techniques. Moreover, trend line analysis was applied as well, as a supplementary method. For the reason that the case company presents new products to the market limited amount of historical data was available. Therefore simple exponential smoothing technique did not show accurate results as desired. However, suggested methods can be applied for testing and learning purposes, supported by currently applied qualitative methods.

Background: Previous studies show that recommendations accuracy partly can be explained by numerous variables. Prior research leave out several variables, which based on theoretical support, may have a connection with accuracy, such as the cash flows’ volatility. Based on the DCF-model’s structure, accuracy of target prices is assumed to have a positive relationship with companies that have stable cash flows. Purpose: The purpose of this thesis is to analyze the accuracy of stock analysts' target prices and their connection with stable cash flows. The purpose of the study is also to analyze the role of less highlighted variables’ relationship with the accuracy of target prices, in combination with earlier investigated variables. Completion: Including less highlighted variables is supported by theory about corporate valuation, where cash flows’ volatility is the main focus of this study. The accuracy of the target prices is analyzed by regression analysis for three time horizons, where the dependent variable is the absolute margin of error and the dependent variables are represented by the explanatory factors that the study examines. The relationships are estimated by OLS, due to the fact that data are unbalanced. Conclusion:  Stock analysts’ target prices present relationships with numerous of the variables examined in the study. The strongest relationships with the accuracy of target prices are shown by cash flows’ variation, the number of stock analysts, goodwill in terms of total capital and companies’ size. The results show that companies with stable cash flow have a positive relationship with the accuracy of target prices, which supports the theories of the DCF-model for valuation of companies with stable cash flow. The estimations show that the accuracy of target prices also is explained by other factors than those this very study investigates. The results show that the accuracy is higher for shorter time horizons. / Bakgrund: Tidigare studier finner att prognosers träffsäkerhet delvis kan förklaras av flertalet variabler. De variabler som studeras i tidigare forskning visar bitvis på tvetydigheter och utelämnar flertalet variabler som utifrån teoretiskt stöd kan ha ett samband med träffsäkerheten, som exempelvis kassaflödens volatilitet. Utifrån DCF-modellens uppbyggnad antas riktkursers träffsäkerhet ha ett positivt samband med bolag som har stabila kassaflöden. Syfte: Studiens syfte är att ekonometrisk analysera träffsäkerheten i aktieanalytikers riktkurser och söka systematiska förklaringsfaktorer till avvikelser mellan riktkurser och de faktisk realiserade kurserna. Fokus ligger på att, i kombination med tidigare undersökta variabler, analysera tidigare mindre uppmärksammade variablers så som kassaflödens samband med riktkursers precision.   Genomförande: Från teori kring bolagsvärdering hämtas stöd för mindre belysta faktorer som kan tänkas påverka riktkursers träffsäkerhet, där kassaflödens volatilitet är studiens huvudsakliga fokus. Riktkursernas träffsäkerhet analyseras via regressionsanalys för tre olika tidshorisonter, där beroendevariabeln är den absoluta felmarginalen i riktkursen och de oberoende variablerna representeras av företagens kassaflöden och övriga påverkansfaktorer som identifierats i tidigare forskning. Studien bygger på data från den amerikanska aktiemarknaden. Slutsats: Aktieanalytikers riktkurser uppvisar samband med flertalet av de variabler studien undersöker. Starkast samband med riktkursers träffsäkerhet visar kassaflödens variation, antalet aktieanalytiker, goodwill i termer av totalt kapital och bolags storlek. Resultaten visar att bolag med stabila kassaflöden har ett positivt samband med riktkursers träffsäkerhet. Detta ger stöd åt DCF-modellens teorier vid värdering av bolag med stabila kassaflöden. Skattningarna visar att riktkursers träffsäkerhet även förklaras av andra faktorer än de som studien undersöker. Resultaten visar att träffsäkerheten är högre för kortare tidshorisonter.

Au cours des dernières années, il a été démontré que la façon dont la douleur est communiquée, par l’entremise de comportements de douleur, est associée à l’incapacité auto-rapportée et à la trajectoire de chronicité des individus souffrant de douleur persistante. Cependant, très peu de recherches ont investigué le lien entre la perception de la douleur dans le couple et la trajectoire de chronicité des individus souffrant de douleur persistante. Dans le cadre de cette thèse, trois études ont été réalisées afin de mieux comprendre les facteurs impliqués dans la communication de la douleur au sein de couples dont l’un des partenaires souffrait de douleur persistante. Une première étude a été réalisée afin de valider une version francophone du « Pain Disability Index (PDI) », un questionnaire développé pour évaluer l’incapacité reliée à la douleur persistante. Comme attendu, les résultats indiquent que cette version du PDI reproduit la structure factorielle de la version originale du PDI et présente une bonne fidélité et validité. Une autre étude a été réalisée auprès de couples dont l’un des partenaires souffre de douleur persistante afin d’évaluer les corrélats de la justesse empathique, d’explorer la relation entre la justesse empathique reliée à la douleur et différentes variables associées à l’adaptation du patient et du conjoint et enfin d’explorer la relation entre la justesse empathique reliée à la douleur et des variables relationnelles. Les résultats suggèrent que de façon générale, la justesse empathique est associée à des résultats négatifs chez les patients souffrant de douleur persistante et ne semble pas un corrélat important de la satisfaction conjugale. Enfin, une dernière étude a été réalisée afin de comprendre l’influence de la concordance des pensées catastrophiques dans le couple sur l’émission de comportements de douleur et sur la perception de la douleur et de l’incapacité lors d’une tâche physiquement exigeante. Il a été trouvé que les participants ayant un niveau élevé de pensées catastrophiques, qui étaient en relation avec un conjoint ayant un faible niveau de pensées catastrophiques, ont émis plus de comportements de douleur que tous les autres groupes. Ces résultats suggèrent que les personnes souffrant de douleur persistante ayant un niveau élevé de pensées catastrophiques peuvent avoir besoin d’augmenter le « volume » de la communication de la douleur afin de compenser pour la tendance des conjoints ayant un faible niveau de pensées catastrophiques à sous-estimer les signaux de douleur. En résumé, puisque l’émission de comportements de douleur est associée à l’incapacité auto-rapportée des individus souffrant de douleur persistante, il est possible que toute situation qui contribue à une augmentation des comportements de douleur, contribuera également à un niveau d’incapacité plus élevé. Ainsi, d’un point de vue clinique, les interventions qui amènent le conjoint à faire de l’écoute active et à valider la personne souffrante, pourraient réduire la présence des comportements de douleur et potentiellement avoir un impact sur le niveau d’incapacité des personnes souffrant de douleur persistante. / In the past, it has been shown that pain communication, through the display of pain behaviours, is related to self-reported disability and pain chronicity. However, few studies have investigated the link between pain perception in couples and the chronic trajectory of individuals suffering from persistent pain. In the current thesis, three studies were conducted in order to understand the factors that are involved in pain communication in couples where one partner suffers from persistent pain. The first study aimed to validate a francophone version of the Pain Disability Index (PDI), a questionnaire, developed to assess disability associated with persistent pain. As expected, the results showed that this version of the PDI replicate the factorial structure of the original version of the PDI and showed a good reliability and validity. Another study was conducted with couples where one partner suffers from persistent pain to investigate the correlates of empathic accuracy, explore the relation between pain-related empathic accuracy and different variables associated with adaptational outcomes for chronic pain patients and their spouses, and explore the relation between pain-related empathic accuracy and relational variables. The results generally suggest that empathic accuracy is associated with negative outcomes for the patient, and might not be an important correlate of marital satisfaction. Finally, a last study was conducted to understand the influence of couple concordance of catastrophizing on the display of pain behaviours and on the perception of pain and disability in a physically demanding task. Results revealed that high catastrophizing pain participants, who were in a relationship with a low catastrophizing spouse, displayed more pain behaviours than all other groups. These findings suggest that high catastrophizing chronic pain persons might need to increase the ‘volume’ of pain communication in order to compensate for low catastrophizing spouses’ tendency to underestimate the severity of their pain experience. In brief, since the display of pain behaviours is related to self-reported disability of chronic pain persons, it is possible that any situation that contributes to the increase of pain behaviours, will also contribute to a higher disability level. Therefore, from a clinical perspective, interventions that lead the spouse to engage in active listening and to respond with validating statements, could reduce the amount of pain behaviours and possibly have an impact on the disability level of chronic pain persons.