Metal-semiconductor contacts have been widely studied in the past 60 years. These structures are of importance in the microelectronics industry. As the scaling down of silicon-based complementary metal-oxide-semiconductor (CMOS) devices becomes more and more challenging, new material and device structures to relax this physical limitation in device scaling are now required. Germanium (Ge) has been proposed as a potential alternative to silicon. In this thesis a systematic study of the thermally induced reaction of transition metals with the n-Ge substrate is outlined. Investigations in the change of the electrical properties of the metal germanide structures is studied in a wide range of temperatures. Current-voltage (I-V), capacitance-voltage (C-V), deep level transient spectroscopy (DLTS) and high-resolution Laplace-DLTS (L-DLTS) techniques have been used for the electrical characterization of the fabricated Schottky contacts. Results obtained indicate the variation of the electrical properties of these Schottky contacts can be attributed to combined effects of interfacial reactions and phase transformation during the annealing process. The barrier height distribution in identically prepared Schottky contacts on n-Ge (100) showed that the barrier heights and ideality factors varied from diode to diode even though they were identically fabricated. The properties of the n-Ge Schottky contacts have revealed a strong dependence on temperature. The current transport mechanism has been shown to be predominantly thermionic emission at high temperatures while at low temperatures, the Schottky contacts have exhibited the dominance of the generation-recombination current mechanism. The variation of the Schottky barrier heights at low temperatures have been attributed to barrier inhomogeneities at the metal-semiconductor (MS) interface. Results from defect characterization by DLTS show that the E-centre is the dominant defect introduced in n-Ge by electron beam deposition during contact fabrication and substitutional related defects are induced during the annealing process. The identification of some of the defects was achieved by using defect properties, defect signature, annealing mechanisms and annealing behaviour and comparing these properties to the results from theoretical defect models. Annealing showed that defects in Ge can be removed by low thermal budget of between 250–350°C. Finally, structural characterization of these samples was performed by scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS) techniques. From the SEM images it can be observed that the onset temperature for agglomeration in the 30 nm Ni/n-Ge (100), and Pt/-, Ir/- and Ru/n-Ge (100) systems occur at 500–600°C and 600–700°C, respectively. / Thesis (PhD)--University of Pretoria, 2010. / Physics / unrestricted

Thesis (M. Sc. (Physiology)) --University of Limpopo, 2019 / Introduction: There is an increased trend in the prevalence of hypertension in children and adolescents in African countries. There are complications in diagnosing hypertension in children and adolescents due to the variation of blood pressure (BP) values with age, gender and height. The progression of the health transition with non-communicable diseases (NCDs) adds significantly to the disease burden, despite infectious diseases and undernutrition remaining persistent in both low and middle-income countries. Metabolic syndrome (MetS) is a global problem associated with the clustering of several cardiovascular risk factors. South African evidence suggests an upsurge of NCDs amidst the existence of communicable diseases (CDs) such as HIV/AIDS and tuberculosis. Moreover, NCDs and CDs in the country are influenced by socio-demographic factors; and thus tend to be more prominent in certain segments of the population. Aim and Objectives: The aim of this study was to perform blood pressure to height ratio and to determine lifestyle risk factors associated with metabolic syndrome among the Ellisras rural population aged 6-30 years, who are part of the ELS. Methods and materials: The current study is based on secondary data analysis of the Ellisras Longitudinal Study (ELS) and was conducted in two phases. Phase 1 included data analysis of all the participants in the ELS. This sample included a total number of 9002 children and adolescents (4678 boys and 4324 girls), aged 6-17 years. Parents or guardians provided written informed consent. Phase 2 consisted of biochemical analysis from a subsample of participants in the ELS. The subsample included 624 participants (306 males and 318 females) aged 18-30 years at the time the study was conducted. All participants underwent a series of anthropometric measurements (waist circumference and height) according to the standard of the International Society for the Advancement of Kinanthropometry (ISAK). The waist circumference (WC) measurements were taken to the nearest 0.1 cm, using a soft measuring tape. Metabolic syndrome was defined according to the International Diabetes Federation (IDF) criteria. Metabolic syndrome risk factors included total cholesterol (TCHOL), triglycerides (TG), high-density lipoprotein cholesterol (HDLC), elevated fasting blood glucose (FBG), elevated blood pressure (BP) and high waist circumference (WC). A dietary intake questionnaire was also administered to each participant and self‑administered questionnaire was used to collect data on lifestyle factors, including smoking and alcohol intake. Dietary intake variables used in the linear regression method were log transformed prior to analysis because of their skewed distribution. Receiver-operating characteristic (ROC) curve was used to assess the accuracy of BPHR to screen children with prehypertension and hypertension. The optimal systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) cut-off points for hypertension were determined. Sensitivity/specificity, positive predictive values and negative predictive values were calculated. Results: The optimal thresholds for defining prehypertension was 0.77 in children aged 6-10 years and 0.73 in adolescents aged between 11 and 17 years for systolic BPHR and 0.55 in children and 0.53 in adolescents for diastolic BPHR, respectively. The corresponding values for hypertension stage 1 were 0.76 and 0.73 for SBPHR and 0.50 and 0.58 for DBPHR, respectively. The BPHR is an accurate tool for screening elevated BP in Ellisras children aged 6-17 years. This can help to prevent the misclassification of children and adolescent hypertension. Furthermore, this tool can be used to screen children before the development of prehypertension and hypertension. Moreover, it can be used to manage hypertension in Ellisras children, ultimately reducing the risks of developing hypertension and associated cardiovascular disease in adulthood. Overall, the prevalence of metS was 23.1% (8.6% males and 36.8% females). Females appeared to have higher mean values for WC, FBG, TCHOL and LDL-C than males (82.14, 5.62, 4.62 and 2.97, respectively). The only significant gender difference observed was on WC (p<0.001). Males on the other hand had higher mean values for HDL-C, TG, SBP and DBP than females (1.20, 1.06, 125.91 and 71.44, respectively). The only significant difference observed in this case was on SBP (p<0.001). No significant age group differences were observed in all the metabolic risk factors with the exception of DBP where the older (25-30 years) participants presented with high SBP than the younger age group (18-24 years) (70.96 mmHg vs 68.78 mmHg, p<0.05). While, majority of females had significantly high WC, elevated total cholesterol and LDL-C, and reduced HDL-C; majority of males had elevated BP, SBP and DBP. No significant age and gender differences were observed on dietary intake. However, according to the linear regression analysis, no association between log total energy, log added sugar, log SFA and log MUFA with metabolic risk factors. There was a low and negative significant association between log fibre with SBP and DBP (β:-0.004, p=0.003 and β:-0.004, p=0.046), respectively, crude. After adjusting for the potential confounding factors, log fibre was also associated with FBG (β:-0.028, p=0.046). Log PUFAs was inversely associated with FBG, HDL-C and SBP crude. Log trans fatty acids was inversely associated with WC, HDL-C and SBP crude. Both log PUFAs and log trans fatty acids were not associated with any metabolic risk factors after adjusting for potential cofounding factors. Log protein was inversely associated with SBP both crude and adjusted for potential cofounding factors. On predicting the actual risk using the logistic regression analysis, participants who had high dietary energy intake were significantly less likely to present with larger WC, low HDL-C and high LDL-C (OR: 0.250 95%CI [0.161;0.389], OR: 0.306 95%CI [0.220;0.425] and OR: 0.583 95%CI [0.418;0.812], respectively), but more likely to presents with elevated FBG, high TCHOL, high TG and hypertension (OR: 1.01 95%CI [0.735;1.386], OR: 1.039 95%CI [0.575;1.337], OR: 1.186 95%CI [0.695;2.023], OR: 5.205 95%CI [3.156;8.585], respectively) crude. After adjusting for age, gender, smoking and alcohol status, high energy intake was more likely to increase two times high the large WC and elevated FBG among study participants (OR: 2.766 95%CI [0.863;3.477] and OR: 2.227 95%CI [1.051;3.328], respectively). Furthermore, low dietary fibre intake was nearly four times more likely to increase the low HDL-C, crude (OR: 3.864 95%CI [1.067;13.988]) crude. Those participants who consumed high trans fats were more likely to present with high FBG (OR:1.424 95%CI [0.985;2.060]), but less likely to present with LDL-C (OR: 0.540 95%CI [0.321;0.906]) crude. However, after adding potential cofounding factors, participants with high fatty acid were less likely to present with high FBG (OR: 0.672 95%CI [0.441;1.023]). Conclusions: MetS is prevalent in young adults in Ellisras and is differentiated by age and gender with more females at an increased rate by virtue of their body size status, reduced HDL-C, elevated FBG and high LDL-C and the diet they consume that is in most cases high energy, more carbohydrates, high added sugar and SFA. Therefore, identifying groups that are at an increased risk and those that are in their early stages of MetS will help improve and prevent the increase of the metS in the future. These results have high policy implications. KEY CONCEPTS Metabolic syndrome; risk factors; blood pressure; blood pressure to height ratio; cardiovascular disease; dietary intake; rural South African.

The purpose of the dissertation is to study, describe and analyses which comparative measurement activities preschool children construct and use, and how they solve problems and communicate when they use the comparative measurement activities whilst playing with Lego (“the Lego play”). The measurement activities chosen are length/height, quantity and time. The empirical material is based on data from two preschool classes with children aged 2 – 5 year, It was collected through participant observation (video captures) of the children’s Lego play. The theoretical starting points in this study are grounded in childhood sociology and the sociocultural perspective. The study assumes the childhood sociology perspective by viewing the children as competent and active in creating meaning as well as controlling and influencing their own and others’ social environment. The sociocultural perspective gives prominence to development and learning, and its related tools and concepts are used to analyses the results of the study. That is, the Lego play is studied in a social context from the child’s perspective, and the sociocultural perspective describes and analyses the child’s use of mathematics and the acquisition of knowledge in the Lego play in a sociocultural context. The results show that children measuring length/height and quantity explored a store of measurement tools in order to make comparisons, and adapted these to the context in question. These were own body, other body, artefacts, numbers and counting. The measurements were used individually and with others, and the solving of the own or shared problems constituted a large share of the time spent constructing models during Lego play. By contrast, the time concept was used mainly as a tool when the children played with their finished Lego models. Thus, a time perspective was added to the child’s finished model, which inspired thoughts and reflections about time used in the Lego play. The children used the time concepts of the present, the past and the future, and also considered the concept of velocity in the context of the timescale. The children’s communication had a large impact on the Lego play, and they expressed their ideas verbally, physically and through action. The children’s use of mathematics was prominent and meaningful during the Lego play.

Long-range communication proves to be a challenge due to the Earth’s curvature, since electromagnetic waves propagate away from the Earth’s surface in a free atmosphere. A possible solution to beyond line-of-sight communication is the atmospheric phenomenon known as the evaporation duct. Ducting occurs when the refractive index of the atmosphere rapidly decreases with height, which leads to ray trajectories bending inward towards the surface of the Earth, effectively creating a waveguide and enabling long-distance communication. In this work, the models by Paulus-Jeske and Babin-Young-Carton are investigated and implemented in MATLAB for calculation of the evaporation duct height and for modelling the refractive index of the atmosphere. The rapid decrease in refractive index giving rise to evaporation ducts occurs due to evaporation of water within the atmosphericsurface layer (&lt;100 m over the surface), which is the domain of turbulent mixing in the atmosphere. With atmospheric data from a Weather API by Meteomatics, Monin-Obukhov similarity theory for the atmospheric surface layer is combined with a bulk flux parameterization scheme from the COARE experiment to determine the air-sea fluxes in the lower troposphere. The surface layer variables with stability functions from Businger-Dyer, Beljaars-Holtslag, Cheng-Brutsaert, and the SHEBA experiment are used in the evaporation duct models proposed by Paulus-Jeske and Babin-Young-Carton to calculate the evaporation duct height, finding that the latter is a valid method with Monin-Obukhov stability functions based on the SHEBA experiment. The modelled refractive index is inserted into an already existing wave propagation model to investigate and validate the findings. / Långdistanskommunikation är en utmaning på grund av jordens krökning, eftersom elektromagnetiska vågor sprider sig bort från jordens yta vid propagering i fri atmosfär. En möjlig lösning för kommunikation bortom siktlinjen är det atmosfäriska fenomenet som kallas avdunstningskanal. Det uppstår när atmosfärens brytningsindex snabbt minskar med höjden, vilket leder till att strålbanorna böjer sig inåt mot jordens yta, vilket i praktiken skapar en vågledare och möjliggör långdistanskommunikation. I detta arbete undersöks och implementeras modeller beskrivna av Paulus-Jeske och Babin-Young-Carton i MATLAB för beräkning av avdunstningskanalens höjd och för modellering av atmosfärens brytningsindex. Den snabba minskningen av brytningsindexet som ger upphov till avdunstningskanaler beror på avdunstning avvatten i det atmosfäriska ytskiktet (&lt;100 m över ytan), som är det område där den turbulenta blandningen i atmosfären sker. Med atmosfäriska data från Weather API av Meteomatics kombineras Monin-Obukhovs likvärdighetsteori för det atmosfäriska ytskiktet med ett parametriseringsschema för bulkflöden från COARE-experimentet för att bestämma luft- och havsflödena i den nedre troposfären. Variablerna för ytskiktet med stabilitetsfunktioner från Businger-Dyer, Beljaars-Holtslag, Cheng-Brutsaert och SHEBA-experimentet används i de modeller för avdunstningskanaler som föreslagits av Paulus-Jeske och Babin-Young-Carton för att beräkna avdunstningskanalens höjd, varvid det konstateras att den sistnämnda metoden är en giltig metod med Monin-Obukhovs stabilitetsfunktioner baserade på SHEBA-experimentet. Det modellerade brytningsindexet införs i en redan befintlig vågutbredningsmodell för att undersöka och validera resultaten.

Despite the obvious importance attached to the psychological significance of height and weight in everyday life, few researchers have studied the relationship of these variables to the sales performance of ordinary life insurance salesmen. In the present study, it was hypothesized that (1) taller and/or heavier ordinary life insurance salesmen are more successful than shorter and/or lighter ordinary life insurance salesmen; (2) those who possess more "ideal statures" are more successful than those who do not; and, secondarily, (3) life insurance companies tend to hire taller and/or heavier applicants for life insurance sales positions. The results of this study offer further support for the view that many sales managers and recruiters tend to believe that "the bigger they are, the better," and to select applicants accordingly, with the qualification that in this sample, female agents were taller, but lighter than average. These findings are discussed in terms of their implications for the life insurance industry and future investigations.

Vilken transportväg är den miljövänligaste för att ta sig från plats A till plats B? För att ta reda på detta krävs det någon form av modell för vägnätet som gör det möjligt att beräkna den totala bränsleförbrukningen för en viss resväg. Ett sätt att skapa en sådan kostnadsmodell är genom att applicera vägnätet på en höjdmodell med mål att vägnätet ska få höjddata. Problemet med denna metod är dock att stora plötsliga höjdskillnader genereras vilket inte motsvarar verkligheten. Syfte med detta arbete är därför att undersöka orsaken eller orsaker till varför stora höjdskillnader uppstår vid en direkt applikation av vägnät på en höjdmodell. I denna studie motsvaras vägnätet av NVDB (Sveriges nationella vägdatabas) som innehåller Sveriges vägar, och höjdmodellen av en höjdmodell framtagen med hjälp av Lantmäteriets laserskanning. Rapporten delas in i två delar - en teoridel och en databearbetning. Den första delen, teoridelen, ska ge en inblick i hur NVDB och Lantmäteriets höjdmodell är framtagna. I denna del finns även information om de tre studieområdena Göteborg, Kiruna och Värnamo. Den andra delen som är databearbetning handlar istället om att slå ihop de två dimensionerna för att senare kunna identifiera eventuella problemområden. För att åstadkomma detta används bland annat Extract By Mask och Focal Statistics i programmet ArcGIS. Resultatet från denna studie visar att den vanligaste orsaken till att problemområden uppstår är att vägnätet i NVDB hamnar utanför den fysiska och verkliga vägen på höjdmodellen. Andra orsaker som kunde identifieras är kritiska punkter såsom tunnlar och broar. Att vägnätet hamnar utanför beror på att generaliseringsregler tillämpas vid framtagning av NVDB. För att lösa problemet med plötsliga höjdförändringar skulle exempelvis interpolation kunna användas för att jämna ut skillnaden. / Which transport route from point A to point B is the most environmentally friendly? To determine it, a model of the road network is needed to calculate the total fuel consumption for a specific route. One way to create this type of cost model is to apply the road network to a height model, intending to assign height data for the road network. However, the problem with this method is that large, sudden height differences occur which do not correspond to reality. The motive of this work is to investigate the cause or causes of why these height differences appear with the direct application of a road network onto a height model. In this report, the road network is NVDB (National Road Database of Sweden) which contains all roads of Sweden, and the height model is a height model produced by the laser scanning of Lantmäteriet. The report is divided into two parts - literature study and data processing. The first part, the literature study, is supposed to give an insight into how NVDB and the height model are created. This part also contains information about the three study areas Göteborg, Kiruna and Värnamo. In the second part, which is the data processing, the two dimensions are merged and are later analyzed to identify any problem areas. To achieve this, the software program ArcGIS is used, and Extract By Mask and Focal Statistics are some used functions. The results from this study indicate that the most common source of problem areas where height differences occur is that the road network in NVDB is placed incorrectly and therefore does not correspond to the physical world whereas often is the road on the height model. Another common source are critical points such as tunnels and bridges. When producing the NVDB, rules of generalization are applied, resulting in the road network placed outside the physical road. A potential solution for the sudden height change is using interpolation between points to level out the height difference.

Bridge abutments are designed to withstand lateral pressures from thermal expansion and seismic forces. Current design curves have been seen to dangerously over- and under-estimate the peak passive resistance and corresponding deflection of abutment backfills. Similar studies on passive pressure have shown that passive resistance changes with different types of constructed backfills. The effects of changing the length to width ratio, or including MSE wingwalls determine passive force-deflection relationships. The purpose of this study is to determine the effects of the wall heights and of the MSE support on passive pressure and backfill failure, and to compare the field results with various predictive methods. To compare the effects of backfill geometries, three large-scale tests with dense compact sand were performed with abutment backfill heights of 3 ft (0.91 m), 5.5 ft (1.68 m), and 5.5 ft (1.68 m) confined with MSE wingwalls. Using an existing pile cap 11 ft (3.35 m) wide and 5.5 ft (1.68 m) high, width to height ratios for the abutment backfills were 3.7 for the 3ft test, and 2.0 for the 5.5ft and MSE tests. The failure surface for the unconfined backfills exhibited a 3D geometry with failure surfaces extending beyond the edge of the cap, increasing the "effective width", and producing a failure "bulb". In contrast, the constraint provided by the MSE wingwalls produced a more 2D failure geometry. The "effective width" of the failure surface increased as the width to height ratio decreased. In terms of total passive force, the unconfined 5.5ft wall provided about 6% more resistance than the 5.5ft MSE wall. However, in terms of passive force/width the MSE wall provided about 70% more resistance than the unconfined wall, which is more consistent with a plane strain, or 2D, failure geometry. In comparison with predicted forces, the MSE curve never seemed to fit, while the 3ft and 5.5ft curves were better represented with different methods. Even with optimizing between both the unconfined curves, the predicted Log Spiral peak passive forces were most accurate, within 12% of the measured peak resistances. The components of passive force between the unconfined tests suggest the passive force is influenced more by frictional resistance and less by the cohesion as the height of the backwall increases.

KL-trä är ett stommaterial som blir allt intressantare på marknaden. Kunskapen är hos mångakonstruktörer idag begränsad. Genom att utgå från en betongstomme, där många konstruktörer har goderfarenhet av projektering och dimensionering, kan en jämförelse mellan dessa två stommaterial vara relevant. Frågan som då kan ställas är hur en KL-trästomme dimensioneras enligt Eurokoderna och vadskillnaderna och dess konsekvenser på boarea och byggnadshöjd, i jämförelse med en betongstomme. Genom att för en byggnad göra om dess betongstomme till en KL-trästomme så kunde dessa skillnader undersökas. KL-trä eller korslimmat trä är ett skivmaterial av sammanlimmade brädor, där vartannat lager liggerkorslagt mot föregående lager. Denna uppbyggnad ger KL-träskivan bärförmåga i två riktningar ochkan användas som vägg- och bjälklagselement. KL-trä är ett stommaterial med låg vikt, jämfört medexempelvis betong, och har precis som andra lätta konstruktioner utmaningar med att uppfylla ljudkrav. Trä som utsätts för brand brinner med en konstant hastighet. Då kolskiktet som bildas har enisolerande effekt, brinner det med en låg hastighet. Detta gör det enkelt att dimensionera för brand. KL-trä har mindre fuktbetingade rörelser jämfört med konstruktionsvirke. Handlingar för en referensbyggnad med betongstomme erhölls av Kåver &amp; Mellin. Med målet attbehålla byggnadens ursprungliga arkitektoniska kvaliteter utformades en ny byggnad i KL-trä därhänsyn togs till krav för bärighet, ljud, värmeisolering, brand och fukt. Resultatet som presenteras är en metod för dimensionering av KL-träväggar och -bjälklag. Därefterföljer en uppställning av typdetaljer för väggar och bjälklag, dess ingående material och till vilken gradkraven uppfyllts. Förslag till anslutningar mellan utvalda byggnadsdelar visas. Boarean minskade iförhållande till referensbyggnaden. Byggnadhöjden alternativt rumshöjden påverkas negativt. KL-träbyggnaden visades väga 118 ton mindre än referensbyggnaden. Vid val av KL-trästomme måste hänsyn tas till den ökade tjockleken av lägenhetsskiljande bjälklagväggar som kan leda till minskad area och ökad byggnadshöjd, och dess ekonomiska konsekvenser. Den påtagliga skillnaden i vikt är betydelsefull vid grundläggning och hantering av vindlaster.

The purpose of this project was to track the posture of a person sitting by a desk, and then use the information to adjust the desk to achieve an optimal height for the user. The solution was to track the angle of the users forearm relative to the desk’s horizontal plane, which should be around zero degrees for an ergonomic posture. Two Light Emitting Diodes (LEDs) in different colours were attached to the user, one at the elbow and one at the wrist. The LEDs were tracked with a camera connected to a laptop running Open Source Computer Vision Library (OpenCV). Window tinting was placed on the camera lens so that only the LEDs and other strong light sources were visible. By using OpenCV, coordinates for the two LEDs were given. With the coordinates found, the angle of the users arm could be calculated and the height of the desk evaluated. Information about necessary height adjustments were sent from the laptop to an Arduino via Bluetooth. The Arduino then controlled a stepper motor by sending signals to a stepper driver, making the motor rotate, thus adjust the height of the desk. The desk was a single leg laptop desk. The leg consists of two tubes. The lower, outer tube was connected to the foot while the upper inner tube, which ran freely in the outer tube, was connected to the tabletop. The height was adjusted with a lead screw positioned parallel to the leg.The nut on the lead screw was connected to the outer lowertube. When the motor rotated so did the lead screw, lifting the table top up or lowering it. / Syftet med detta project var att undersöka om det är möjligt att i realtid spåra en persons hållning vid ett skrivbord, och använda den informationen för att justera skrivbordet höjd och nå en optimal höjd för användaren. Lösningen var att spåra vinkeln på användarens underarm relativt skrivbordets horisontalplan, som bör vara runt noll grader för en ergonomisk ställning. Två lysdioder i olika färger placeras på användaren, en på armbågen och en på handleden. Med hjälp av OpenCV spårades lysdioderna med en kamera kopplad till en dator. Solfilm sattes på kameralinsen så att endast lysdioderna och andra starka ljuskällor var synliga. Genom att använda OpenCV togs koordinaterna för lysdioderna fram. Med koordinaterna kunde vinkeln på användarens underarm beräknas och skrivbordets höjd utvärderas. Information om nödvändiga höjdändringar skickades från laptopen till en Arduino via Bluetooth. Arduinon kontrollerade en stegmotor genom att skicka signaler till en stegmotordrivare, vilket fick motorn att rotera och justera skrivbordets höjd. Skrivbordet var ett enbent laptopställ. Benet bestod av två rör. Det nedre yttre röret satt fast i foten och det övre inre röret satt fast i bordsskivan, och löpte fritt i det yttre röret. Höjden justerades med en gängstav som satt parallellt med benet. Muttern satt ihop med det nedre röret. När motorn roterade gjorder också gängstaven det, vilket antingen pressade upp bordsskivan eller sänkte den.

The purpose of this project was to track the posture of aperson sitting by a desk, and then use the information toadjust the desk to achieve an optimal height for the user.The solution was to track the angle of the users forearm relativeto the desk’s horizontal plane, which should be aroundzero degrees for an ergonomic posture. Two Light EmittingDiodes (LEDs) in different colours were attached tothe user, one at the elbow and one at the wrist. The LEDswere tracked with a camera connected to a laptop runningOpen Source Computer Vision Library (OpenCV). Windowtinting was placed on the camera lens so that only theLEDs and other strong light sources were visible. By usingOpenCV, coordinates for the two LEDs were given. Withthe coordinates found, the angle of the users arm couldbe calculated and the height of the desk evaluated. Informationabout necessary height adjustments were sent fromthe laptop to an Arduino via Bluetooth. The Arduino thencontrolled a stepper motor by sending signals to a stepperdriver, making the motor rotate, thus adjust the height ofthe desk.The desk was a single leg laptop desk. The leg consistsof two tubes. The lower, outer tube was connected to thefoot while the upper inner tube, which ran freely in theouter tube, was connected to the tabletop. The height wasadjusted with a lead screw positioned parallel to the leg.The nut on the lead screw was connected to the outer lowertube. When the motor rotated so did the lead screw, liftingthe table top up or lowering it. / Syftet med detta project var att undersöka om det är möjligtatt i realtid spåra en persons hållning vid ett skrivbord, ochanvända den informationen för att justera skrivbordet höjdoch nå en optimal höjd för användaren.Lösningen var att spåra vinkeln på användarens underarmrelativt skrivbordets horisontalplan, som bör vara runt nollgrader för en ergonomisk ställning. Två lysdioder i olikafärger placeras på användaren, en på armbågen och en påhandleden. Med hjälp av OpenCV spårades lysdioderna meden kamera kopplad till en dator. Solfilm sattes på kameralinsenså att endast lysdioderna och andra starka ljuskällorvar synliga. Genom att använda OpenCV togs koordinaternaför lysdioderna fram. Med koordinaterna kunde vinkelnpå användarens underarm beräknas och skrivbordets höjdutvärderas. Information om nödvändiga höjdändringar skickadesfrån laptopen till en Arduino via Bluetooth. Arduinonkontrollerade en stegmotor genom att skicka signalertill en stegmotordrivare, vilket fick motorn att rotera ochjustera skrivbordets höjd.Skrivbordet var ett enbent laptopställ. Benet bestod av tvårör. Det nedre yttre röret satt fast i foten och det övre inreröret satt fast i bordsskivan, och löpte fritt i det yttre röret.Höjden justerades med en gångstav som satt parallellt medbenet. Muttern satt ihop med det nedre röret. När motornroterade gjorder också gångstaven det, vilket antingen pressadeupp bordsskivan eller sänkte den.