Serial articulated industrial manipulators are increasingly used in machining applications due to their flexibility in application and their cost-effectiveness compared to conventional machinery. However, the use of industrial manipulators in machining processes that subject the robot to high loads such as in drilling is limited. The relatively low mechanical stiffness leads to position offsets from the anticipated position. Efforts have been made in the past to create manipulator calibration methods to compensate for their low stiffness and to increase their pose accuracy. The Department of Production Engineering at KTH Royal Institute of Technology defined a static and quasi-static compliance calibration procedure for industrial manipulators. Contrary to the hypothesis, the two methods produce different results in terms of the measured magnitude of Cartesian deflections. This study compares static and quasi-static compliance measurement procedures on an ABB IRB 6700-300/2.70 and aims at finding causes for the difference in the measured deflection of the manipulator between the two methods. Therefore, a literature review is performed and based on the review a novel quasi-static measurement procedure is presented. Deflections during the application of static and quasi-static loads with a frequency of less than 0.5 Hz on the manipulator are measured and compared. Differences in deflection are seen and potential causes are analyzed in several experiments. Namely, by changing parameters the resulting effects on the manipulator due to kinematic errors and dynamic effects are investigated. The results stress that unlike the expectation based on the theory of mechanics the system shows a dynamic behavior if a periodic loading with a frequency of less than 0.5Hz is applied during the quasi-static experiments. The difference in deflection is thus explained through load dissipation by damping and inertial forces during the quasi-static measurements of the novel method. This does not apply to the quasi-static measurement procedure defined by the Production Engineering department. Moreover, differences in deflection were identified due to friction and backlash acting in the transmissions system of the motors when static loads are applied in certain regions of the task space. Future work in the analysis of differences in compliance measurement procedures is encouraged to find causes for the quasi-static measurement results of the department. / Serieartikulerade industriella manipulatorer används allt mer i bearbetande operationer tack vare dess flexibilitet i användande och dess kostnadseffektivitet jämfört med konventionella maskiner. Dock är användandet av industriella manipulatorer i bearbetningsprocesser som utsätter roboten för höga laster så som borrande begränsat. Den relativt höga mekaniska stelheten leder till positionsförskjutningar från den förväntade positionen. Ansträngningar har tidigare gjorts för att skapa kalibreringsmetoder för manipulatorer som ska kompensera för dess låga stelhet och öka dess position och orienterings-exakthet. Institutionen för industriell produktion vid Kungliga Tekniska Högskolan har definerat en statisk och kvasistatisk efterlevnads-kalibrerings-procedur för industriella manipulatorer. I motsats till hypotesen producerade de två metoderna olika resultat i avseende till den uppmätta magnituden för Kartesiska böjningar. Denna studie jämför statiska och kvasistatiska efterlevnads-mätnings-procedurer hos en ABB IRB 6700-300/2.70 och siktar på att hitta orsaker för skillnaden i den uppmätta böjningen av manipulatorn mellan de två metoderna. Därmed genomförs en litteraturstudie och baserat på en översikt presenteras en ny kvasistatisk mätningsprocedur. Böjningar under påverkan av statiska och kvasistatiska laster på under 0.5 Hz på manipulatorn uppmäts och jämförs. Skillnader i böjningar kan ses och potentiella orsaker analyseras i flera experiment. Genom byte av parametrar kan effekter på den industriella manipulatorn som orsakas av kinematiska fel och dynamiska effekter undersökas. Resultatet understryker att olikt förväntningarna som baserats på teorier från mekaniken uppvisar systemet ett dymaniskt beteende om en periodisk last på mindre än 0.5 Hz appliceras under de kvasistatiska experimenten. Skillnaden i böjningen förklaras därmed genom ett lastminskande som beror på dämpande och tröga krafter under de kvasistatiska mätningarna av den nya metoden. Detta gäller inte den kvasistatiska mätningsproceduren som definerats av Institutionen för industriell produktion. Utöver detta identifieras skillnader i böjningar med avseende på friktion och glapp i överföringssystemet i motorerna när statiska laster appliceras på specifika regioner i arbetsområdet. Framtida arbete i analys av skillnader i efterlevnadsmätnings-procedurerna uppmuntras för att hitta orsaker till institutionens kvasistatiska mätningsresultat.

<p>The purpose of this study was to examine the effects of depleted self-regulation on skillful task performance. Participants completed a baseline dart-tossing task (20 tosses), and were instructed to toss as quickly and as close to the bulls-eye as possible when a particular cue light flashed. Participants then underwent a self-regulatory depleting (experimental) or a non-depleting (control) manipulation before completing a second round of dart tossing. Measures of accuracy, reaction time, and myoelectrical activity of the biceps and triceps were collected along with self-report measures of psychological resilience and trait self-control.</p> <p>As hypothesized, participants in the experimental condition had poorer mean accuracy at round two than control condition participants, as well as a significant decline in accuracy from round one to round two. These effects were moderated by trait self-control; experimental group participants with higher trait self-control were more accurate in round two than experimental group participants with lower trait self-control. Experimental group participants also demonstrated poorer consistency in accuracy compared to control group participants at round two, and a significant deterioration in consistency from round one to round two. The only significant finding regarding reaction time was that consistency improved significantly for the control group but not for the experimental group.</p> <p>The results of this study provide evidence that ego depletion effects occur for skill-based physical task performance, especially in regards to accuracy. These findings provide further support for the utility of the limited strength model and suggest that self-regulatory depletion can impact performance on skill-based physical tasks.</p> / Master of Science in Kinesiology

Additive manufacturing (AM) has the ability to fabricate components of high geometric complexity that are difficult or near impossible to be produced by traditional manufacturing technologies. Selective laser melting (SLM) is a commonly used AM technology for metallic fabrications. SLM offers the opportunities to customize the characteristics of the as-build part produced, by adjusting the laser settings. However, high strength aluminum (Al) alloys presents an obstacle for SLM production due to the low alloying content, which increases the alloys’ probabilities to form cracks due to thermal stress induced by the SLM build process. The current study focuses on the study of surface roughness and dimensional accuracy of SLM fabrication of Al6061 and AlSi10Mg. Using design of experiment (DOE), wide ranges SLM process parameters were experimented with, and their individual effect along with their interactive effects on the fabricated parts’ quality were evaluated. The quality characteristics studied are: microstructures, microhardness, tensile strength (ultimate tensile strength, and yield strength), density, surface roughness, and dimensional accuracy. Regression models were created for each quality characteristics, and the combination of density, surface roughness, and dimensional accuracy results was used to create processing window for SLM that ensures the production of high-quality parts. The work aims to not only be used as-is, to help with the selection of SLM process parameters for Al6061 and AlSi10Mg that will reduce the post- processing time, but also to set a foundation for future development for numerical models that could better predict and describe the relations between SLM process parameters and the part’s fundamental qualities. / Thesis / Master of Applied Science (MASc)

OBJECTIVES: The objective was to investigate the accuracy, storage stability, and mechanical properties of 3D-printed polymeric dental materials. MATERIALS AND METHODS: Three completely dentate models, two maxillary and one mandibular each with their respective die, and three implant models were designed using dental CAD software (3SHAPE DENTAL SYSTEM). A horseshoe-shaped solid base with a posterior horizontal bar was utilized. The models were printed based on the manufacturer's instructions for four weeks using six printers with the corresponding recommended resin materials: Carbon M2 (DPR10), HeyGears A2D4K (Model HP UV2.0), Stratasys J5 (MED610), Stratasys Origin One (DM200), Envision One (E-Model LightDLP), and Asiga Pro4K (VeriModel) with a standard layer thickness of 50 μm (N=72). The models were scanned after printing using Sirona inEOS X5 scanner, while the implant models were scanned using a CT scanner (GE Phoenix V|tome|x metrology edition). The full arch models were randomly assigned to three groups of storage conditions: cold environment (LT, 4 ± 1°C), hot and dry environment (HT, 50 ± 2°C), and room temperature (RT , 25 ± 2°C, serving as the control). Each group was kept under the designated conditions and scanned at 1, 2, 3, 4, and 8 weeks. The generated STL files were imported into a 3D inspection software for comparison with the original STL files. Four sets of reference points (central fossa of first premolars and central fossae of second molars) were selected to determine six distances of inter-arch segments, from which the inter-arch distance trueness and precision deviation were measured. For the second part of the study, maxillary Lucitone Digital Print denture base (DB) (N=5), maxillary Lucitone IPN 3D Premium anterior and posterior teeth (N=6), and maxillary Keystone Keysplint Soft Clear occlusal splint (N=5) were printed using two printers (Carbon M2, Asiga Max UV) with a standard layer thickness of 50 μm for denture base and teeth, and 100 μm for the occlusal splint. The tolerance threshold was set to 50 μm for Lucitone IPN and 100 μm for Lucitone DB and Keysplint Soft. In-tolerance percentage and deviation RMS were obtained and analyzed with multivariate least square mean linear regression using JMP Pro 17 (SAS, Cary, NC) to identify significant effects (α=0.05). The third part investigated the mechanical properties of Lucitone DB and IPN using 2 printers (Carbon M2, Asiga Max UV) as follows: flexural strength (N=10) using a threepoint bend test, fracture toughness (N=10), creep (N=5), Vickers hardness test (N=15), surface roughness (N=15), while Shore A hardness (N=15) and tensile strength (N=10) were performed for Keysplint Soft Clear. Data were analyzed using one-way and multivariate least square mean linear regression followed by Tukey’s HSD test using JMP Pro 17 (SAS, Cary, NC) to identify significant effects (α=0.05). RESULTS: The in-tolerance percentage varied significantly among printers, with Carbon M2 (CAB) showing the highest values. Stratasys (J5) displayed the highest accuracy in term of precision, while HeyGears A2D4K (HGS), Carbon M2 (CAB), and Stratasys (J5) exhibited the highest accuracy in term of trueness. The inter-molar segment showed the highest deviation. No significant difference was observed in in-tolerance percentage across different print weeks except for week 2 in one printer (Stratasys Origin1). CAB exhibited a higher in-tolerance percentage for the DB than Asiga Max UV (ASG), with the fitting surface having the highest in-tolerance percentage. IPN anterior teeth had a higher intolerance percentage than posterior teeth, with ASG showing a higher value than CAB. No statistically significant difference was found in the in-tolerance percentage of Keysplint Soft Clear between ASG and CAB. Resin printed using ASG demonstrated higher flexural strength, Vickers hardness, and creep, while resin printer using CAB exhibited higher fracture toughness, with no significant difference in surface roughness between the two printers. Lucitone IPN had higher flexural strength and Vickers hardness, surface roughness , and lower creep and fracture toughness than Lucitone DB. CAB Keysplint Soft had higher tensile strength than ASG, with no statistically significant difference in Shore A hardness between the two printers. CONCLUSION: Model dimension deviations were impacted by storage conditions and the specific printer utilized, with high-temperature storage exhibiting the least stability. However, no significant difference was noted between low and room temperature storage conditions. Carbon M2 exhibited the highest level of accuracy. The of 3D-printed denture bases and denture teeth varied across different printers. Conversely, no significant difference in accuracy was observed for a soft occlusal splint between two printers. Materials printed using different printers showed statistically significant different mechanical properties.

Yes / Huntington’s disease (HD) is associated with impairments in dual-task performance. Despite that, only a few studies have investigated dual-tasking in HD. We examined dual-task performance in 15 participants in the early stages of HD and 15 healthy controls. Participants performed direct circle tracing (able to view arm) and indirect circle tracing (arm obscured) either on their own (single tasks) or paired with serial subtraction by twos or threes (dual tasks). Overall, our results suggested that HD participants were significantly slower and less accurate than controls. Both groups were slower and less accurate when performing indirect circle tracing compared with direct circle tracing. HD participants experienced greater dual-task interference in terms of accuracy when performing direct circle tracing compared with indirect circle tracing. Despite that, controls were more inclined to speed–accuracy trade-offs compared with HD participants. Importantly, unlike controls, HD participants were not disproportionately faster when performing direct circle tracing as a single task compared with the dual-task conditions. Our results suggest that simple tasks place greater attentional demands on HD participants compared with controls. These findings support that impaired automaticity may be responsible for some of the attentional deficits manifested in HD. / Supported by the School of Psychological Sciences, Monash University.

Yes / The aim of this study was to investigate age-related differences in dual task performance by using an upper limb proprioceptive task. Twenty-eight younger (18–30 years) and 28 older (>60 years) healthy adults performed circle tracing and serial subtraction tasks separately and concurrently. The tasks had two levels of difficulty: easy and hard. The circle tracing task included direct (easy) and indirect (hard) visual feedback conditions, and it was paired with serial subtraction by twos (easy) or threes (hard). We found that older adults were significantly slower than younger adults across all conditions and had significantly greater dual task costs when they performed circle tracing with easy serial subtraction. Higher levels of task difficulty were associated with slower speed in both groups. We found no age differences in accuracy. Participants either traded speed for accuracy or accuracy for speed regardless of age group. Overall, the findings suggest that speed and accuracy may be affected differently during dual tasking. In addition, older adults may rely more extensively on proprioceptive feedback to guide upper limb movement compared with younger adults. / Financial support for this study was obtained from the School of Psychology and Psychiatry, Monash University.

A detailed code verification study of an unstructured finite volume Computational Fluid Dynamics (CFD) code is performed. The Method of Manufactured Solutions is used to generate exact solutions for the Euler and Navier-Stokes equations to verify the correctness of the code through order of accuracy testing. The verification testing is performed on different mesh types which include triangular and quadrilateral elements in 2D and tetrahedral, prismatic, and hexahedral elements in 3D. The requirements of systematic mesh refinement are discussed, particularly in regards to unstructured meshes. Different code options verified include the baseline steady state governing equations, transport models, turbulence models, boundary conditions and unsteady flows. Coding mistakes, algorithm inconsistencies, and mesh quality sensitivities uncovered during the code verification are presented. In recent years, there has been significant work on the development of algorithms for the compressible Navier-Stokes equations on unstructured grids. One of the challenging tasks during the development of these algorithms is the formulation of consistent and accurate diffusion operators. The robustness and accuracy of diffusion operators depends on mesh quality. A survey of diffusion operators for compressible CFD solvers is conducted to understand different formulation procedures for diffusion fluxes. A patch-wise version of the Method of Manufactured Solutions is used to test the accuracy of selected diffusion operators. This testing of diffusion operators is limited to cell-centered finite volume methods which are formally second order accurate. These diffusion operators are tested and compared on different 2D mesh topologies to study the effect of mesh quality (stretching, aspect ratio, skewness, and curvature) on their numerical accuracy. Quantities examined include the numerical approximation errors and order of accuracy associated with face gradient reconstruction. From the analysis, defects in some of the numerical formulations are identified along with some robust and accurate diffusion operators. / Ph. D.

This study identified the accuracy with which local career and technical education (CTE) administrators perceive the stereotypes of CTE students, teachers, and programs held by Virginia Department of Education administrators. In order to measure the aforementioned meta-accuracy: (a) the stereotypes of CTE students, teachers, and programs held by (VDOE) administrators were determined, (b) the meta-stereotypes of local CTE administrators regarding the stereotypes of CTE programs, students, and teachers held by VDOE administrators were established, and (c) the stereotypes and the meta-stereotypes were compared. Data analyzed revealed that some of the traditional stereotypical descriptors of CTE teachers, students, and programs were held by VDOE administrators. Some stereotypes of note were: (a) CTE students do not plan to go to college, (b) CTE students are good with concrete concepts, (c) CTE students enjoy nonacademic classes more than academic ones, (d) CTE students are not from middle to upper socioeconomic class, (e) CTE teachers have lots of on-the-job experience, and (f) CTE programs are isolated from the rest of the school. Local CTE administrators possessed meta-stereotypes that indicated that VDOE administrators would stereotype CTE students as: (a) not being leaders in school, (b) not having college-educated parents, (c) being motivated by material rewards, (d) enjoying nonacademic classes more than academic ones, (e) being easily influenced by peers, and (f) not being from middle to upper socio-economic class. Local CTE administrators had meta-stereotypes that indicated VDOE administrators would stereotype CTE teachers as: (a) being more of a practitioner than a theorist, (b) being good with concrete concepts, and (c) not possessing master's degrees. Local CTE administrators had meta-stereotypes that indicated VDOE administrators would stereotype CTE programs as: (a) being a good return on investment, (b) providing for the education of the whole person, (c) being beneficial to all students, (d) being expensive to maintain, (e) having enrollment typically of students from blue-collar or agriculture background, and (f) being for students who work better with their hands. Local CTE administrators were accurately able to predict the way VDOE administrators would respond to the statements depicting stereotypes of CTE students, teachers, and programs for 45 of the 62 items. Conversely, they were not able to accurately predict 17 out of the 62 statements. Overall, the accuracy of the meta-stereotypes (meta-accuracy) of local CTE administrators varied depending upon what was being measured. The meta-accuracy in relation to CTE teachers was highest (11 out of the 12 items) and the meta-accuracy was lowest in relation to CTE programs (10 out of 17 items). In relation to CTE students, local CTE administrators were accurate in predicting 24 out of the 33 items. / Ph. D.

The O*NET was built to replace the Dictionary of Occupational Titles (DOT) and form a highly accessible, on-line (through the World Wide Web), common language occupational information center (Dye & Silver, 1999). This study tested the relevance of the self-rating choice and unconventional BARS format to be used by the O*NET system for occupational ratings. In addition, a new rating scale format named NBADS, was tested for improved ratings. Fifty three Incumbent raters in two occupations (Graduate teaching assistants and Secretaries) and 87 laypeople raters who have never worked in these occupations, rated 21 item-pairs (Importance and Level type questions) picked randomly from the 52 items on the original O*NET Ability questionnaire. Participants rated each of the 21 item-pairs three times, with the Level question being presented in the O*NET BARS, a Likert GRS and the NBADS formats; The importance type question was always rated using a 1-5 Likert scale. Hypothesis 1a was supported, showing a significant leniency bias across formats for self-ratings. Hypothesis 1b was mostly supported, failing to show significant leniency, elevation error or interrater agreement improvement over laypeople ratings; only the overall-error measure showed a significant improvement for incumbent raters. Hypothesis 2 was not supported, failing to show that the GRS format had any improvement on leniency, accuracy or interrater agreement over the O*NET BARS format. Hypothesis 3a was supported, showing significant leniency reduction, accuracy error reduction and higher interrater agreement using the NBADS format over the GRS format. In a similar sense, hypothesis 3b was partially supported, showing reduction in leniency effect and higher agreement using the NBADS format over the O*NET BARS format. Finally, hypothesis 4 was mostly supported, showing hardly any significant differences in the ratings of the Importance type question across the three format sessions, strengthening the idea that no other interfering variables have caused the format sessions' differences. Implications of the results are discussed. / Master of Science

Analytiker innehar en viktig roll som en informationsintermediär på den finansiella marknaden. Begränsat informationsunderlag samt subjektiva tolkningar kan däremot påverka analytikers träffsäkerhet. Därmed blir det relevant att studera dessa tillkortakommanden.  Syftet med denna uppsats är att förklara hur närhet och kulturell kontext påverkar analytikers riktkursträffsäkerhet. Studien har en deduktivt ansats och ett systemorienterat angreppsätt där närhetsteori, kulturdimensionsteori, institutionell teori och intressentteori är i fokus. Studien har en tvärsnittsdesign, där data från Infront och Refinitiv använts för perioden Q3 2022 till Q3 2023.  Studien kom fram till att svenska analytiker har mer optimistiska men mindre träffsäkra riktkurser på den svenska aktiemarknaden än utländska analytiker. Kunskapsbidraget är att analytiker blir starkt påverkade av sin geografiska omgivning. Utav de valda systemorienterade teorierna kunde endast intressentteorin förklara studiens samband. / Analysts have an important role in the financial market as an information intermediary. Limited information and subjective interpretations do however affect accuracy. Because of that it is relevant to study these shortcomings. The purpose of this essay is to explain how proximity and cultural context effects the analyst´s target price accuracy. The essay has a deductive approach with a system-oriented perspective where proximity theory, cultural dimension theory, institutional theory and stake holder theory is in focus. The study uses a cross-sectional design where data has been gathered from Infront and Refinitiv for period Q3 2022 until Q3 2023. Our essay concluded that Swedish analysts have more optimistic but less accurate target prices in the Swedish stock market then foreign analysts. The research contribution is that analyst is strongly affected by its geographical surroundings. Out of the selected system-oriented theories, only stakeholder-theory could predict the results of the study.