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Numerical Investigation of the Effects of Shrinkage and Thermal Loading on the Behaviour of Misaligned Dowels in Jointed Concrete PavementLevy, Cyril January 2010 (has links)
Dowel bars in jointed plain concrete pavement (JPCP) have the important function of transferring wheel loads from one slab to the other, hence ensuring that the deflections on each side of the joint are kept almost equal. As well, the dowels should not impede the concrete pavement movements due to environmental effects (temperature and moisture). Dowel bar misalignment, attributed to deficient construction practice, is a major cause of joint distress or faulting by inhibiting the free movement of the slab at the joint. To prevent these issues, tolerance guidelines on misalignment levels are implemented by transportation agencies. Review of previous studies indicate that many researchers analysed the effects of dowel bar misalignment on pavement behaviour using a pull-out test, that is a forcebased opening of the joint. These approaches neglect that joints movements in the field are strain-governed by non-linear temperature and shrinkage actions, leading to combined axial
movements and curling of the slab.
In this study, the fundamental dowel bar behaviour under shrinkage and thermal loading
was determined through detailed 3D finite element modelling (3D-FEM). To that end, models of dowel jointed concrete slabs were developed and subjected to realistic non-linear profiles of shrinkage and thermal strains. Studies were carried out on a single-bar model, taking into account bar-concrete friction and plastic concrete behaviour. The parameters that were investigated included different configurations and levels of bar misalignment and different friction coefficients between the steel and the concrete, simulating the use of bond-breakers. To interpret the results from the numerical analysis, criteria for concrete damage were developed and used in parallel with measures of joint load transfer efficiency; these were obtained by examining the response of the slab under a Falling Weight Deflectometer (FWD) drop at the joint. The results were verified by comparing the outputs of a model consisting
of one half of a slab to published data.
The analysis of the models revealead that none of the models showed signs of significant damage after the application of shrinkage and two thermal cycles. Analyses with up to ten thermal cycles did not indicate progressive accumulation of damage, suggesting that for the chosen parameters there is no the concrete around the dowel bar will not fail. Models with bars placed higher in the slab and bars with angular misalignment exhibited more damage than the non-misaligned models without reaching the damage criteria used in this study. The models did not exhibit the amount of damage reported in the studies on dowel bar misalignment having used pull-out tests. It was found that no significant difference existed between uncoated and coated dowel bars models results with regards to concrete damage at the joint. However, a high coefficient of friction between the dowel and the concrete, simulating dowel bar corrosion, proved to be the most detrimental to joint integrity. All of the models performed very well with respect to joint load transfer efficiency, suggesting that
the plastic strains in the concrete around the dowel did not have a significant impact on joint performance for the realistic range of parameters investigated.
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Computer-aided diagnosis of complications of total hip replacement X-ray imagesAl-Zadjali, Najiba January 2017 (has links)
Hip replacement surgery has experienced a dramatic evolution in recent years supported by the latest developments in many areas of technology and surgical procedures. Unfortunately complications that follow hip replacement surgery remains the most challenging dilemma faced both by the patients and medical experts. The thesis presents a novel approach to segment the prosthesis of a THR surgical process by using an Active Contour Model (ACM) that is initiated via an automatically detected seed point within the enarthrosis region of the prosthesis. The circular area is detected via the use of a Fast, Randomized Circle Detection Algorithm. Experimental results are provided to compare the performance of the proposed ACM based approach to popular thresholding based approaches. Further an approach to automatically detect the Obturator Foramen using an ACM approach is also presented. Based on analysis of how medical experts carry out the detection of loosening and subsidence of a prosthesis and the presence of infections around the prosthesis area, this thesis presents novel computational analysis concepts to identify the key feature points of the prosthesis that are required to detect all of the above three types of complications. Initially key points along the prosthesis boundary are determined by measuring the curvature on the surface of the prosthesis. By traversing the edge pixels, starting from one end of the boundary of a detected prosthesis, the curvature values are determined and effectively used to determine key points of the prosthesis surface and their relative positioning. After the key-points are detected, pixel value gradients across the boundary of the prosthesis are determined along the boundary of the prosthesis to determine the presence of subsidence, loosening and infections. Experimental results and analysis are presented to show that the presence of subsidence is determined by the identification of dark pixels around the convex bend closest to the stem area of the prosthesis and away from it. The presence of loosening is determined by the additional presence of dark regions just outside the two straight line edges of the stem area of the prosthesis. The presence of infections is represented by the determination of dark areas around the tip of the stem of the prosthesis. All three complications are thus determined by a single process where the detailed analysis defer. The experimental results presented show the effectiveness of all proposed approaches which are also compared and validated against the ground truth recorded manually with expert user input.
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Misalignment of Stakeholder Objectives In Software start-ups : A Qualitative research based on Software start-ups in IndiaGopagoni, Naveen Kumar, Sabbella, Sri Ranganath Reddy January 2020 (has links)
Context: Misalignment of stakeholder objectives generally takes place in any of the software company irrespective of the small, middle, large scale companies if the misalignment takes place then the goal the project doesn't reach and the objective changes. These misalignment's lead to project failure. Failures of the project in start-ups company some times lead to the shutdown of a company permanently. Minimizing the misalignment in a company means to avoid the risk. Mostly it is more critical for the software start-ups. Objectives: The main aim of our research is to know the factors responsible for the misalignment of the stakeholder objectives in software start-ups along with the significant challenges and possible solutions. Methods: In this qualitative research, we conducted the semi-structured interviews from the twelve start-up companies and collected the data for the research questions. The collected information is then thematically analyzed. We referred to many articles from the google scholar to find the significant challenges responsible for the misalignment of the stakeholder objectives. Results: The main findings in our research are as follows RQ1 external sponsor with his focus on return on investment discussed by the ten out of twelve software start-ups. In the twelve companies, ten companies are dependent on the external sponsor. Human factor and the requirements prioritization are the factors discussed by the six and five interviewees of the start-up companies. The remote working, last-minute change of requirements, deadlines are discussed by two interviewees. The one interviewee discusses the technology factor. In the findings from RQ2, we observed that the challenges related to the humans, return on investment, the external sponsor is more dominant compared to others factors like technology factor, deadlines, remote working, a last-minute change of requirements. In the findings of RQ3, about the possible solutions for the challenges with the misalignment of stakeholder objectives. Conclusions: The results of this study may help the furthers researchers who can research on the misalignment of the stakeholder objectives in software start-ups. These solutions may help the software industry people to minimise the general challenges in future in a better way. This results also may use for the people who want to start a software start-up so that they can know the factors, challenges, solutions of the misalignment of the stakeholder objectives in software start-ups.
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The Acute Effects of Whole-Body Corrective Exercise on Postural AlignmentRencher, Nicole Renee 01 March 2014 (has links) (PDF)
This study examined the acute effects of whole-body corrective exercise on postural alignment in a sample of 50 male participants (18-30 y) displaying asymmetrical postural deviations. All participants were randomly assigned to either a non-exercise control (n = 25) or corrective exercise treatment (n = 25) group. A three-dimensional motion analysis Vicon system was employed to quantify standing postural alignment at the beginning and end of a 6 d study. Postural misalignments were determined in degrees of symmetry (tilt) and rotation using horizontal and vertical virtual plumb lines for the following locations: hip (ASIS), leg (greater trochanter), shoulder (acromion process), and head (ear). The treatment group completed five corrective exercise sessions on separate days which included 11 exercises (requiring about 60 min per session to complete). The control group performed no intervention and maintained a normal lifestyle. At the commencement of the study there were no significant differences in the degree of postural misalignment between the control and treatment groups at any of the postural measurements. At the conclusion of the treatment period (following the five sessions of corrective exercise), there were no significant differences in any of the postural alignments of any of the postural measurements between the treatment and control groups. For example, all of the following postural measurements were not significantly different (critical F ≥ 4.24;df = 1,25) between groups: hip (ASIS) tilt (F = 0.05), hip (ASIS) rotation (F = 0.15), greater trochanter tilt (F = 1.58), greater trochanter rotation (F = 0.33), shoulder tilt (F = 2.63), shoulder rotation (F = 0.07), head tilt (F = 2.39), and head rotation (F = 2.79). The results of this study suggest that five sessions of corrective exercise were insufficient to significantly improve standing postural alignment. In addition, this study appears to be the first to document whole-body postural alignment using 3D video analysis.
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Effects of Exchange Rate Misalignment on Agricultural Producer Support Estimates: Empirical Evidence from India and ChinaCheng, Fuzhi 31 October 2005 (has links)
There have been different degrees of exchange rate disequilibrium in the developing countries during recent transition or reform periods. The level of the exchange rate and its misalignment can have significant impacts on agricultural policy measures such as the Producer Support Estimates (PSEs). However, little efforts have been made to explicitly take into account the issue of exchange rate misalignment. In the conventional PSE studies the prevailing actual (nominal) exchange rates are usually used. There is general agreement that the use of actual exchange rates may introduce a bias in the PSE calculations, and that this bias can be substantial when the actual rates are significantly out of equilibrium, but there is much less agreement on the most appropriate alternative.
This dissertation proposes a theoretical and an empirical model for estimating equilibrium exchange rates. Within the context of these models, the equilibrium exchange rates are argued to be determined by a group of real economic fundamentals. These fundamentals within this study include technological progress (Balassa-Samuelson effect), levels of government expenditure, world interest rate, net capital inflows, terms of trade, and openness of the economy. Base on various time series techniques and using data from India and China, sensible long-run relationships are identified between the real exchange rate and these economic fundamentals. The long-run co-integrating relationships are used to derive the equilibrium exchange rates and to gauge corresponding misalignments for the currencies in the two countries.
The relevance and usefulness of the exchange rate equilibrium and disequilibrium in the calculation of the PSEs for India and China are then discussed. Results from the commodity-specific measures including the Market Price Support (MPS) and the PSE show that agricultural support levels are quite sensitive to alternative exchange rate assumptions. Specifically, exchange rate misalignments have either amplified or counteracted the direct effect on agriculture from sectoral-specific policies. With a few commodity exceptions such an indirect effect in both countries is relatively small in magnitude and dominated by the direct effect. This is also the case when the indirect effect rises substantially as a result of more misaligned exchange rates. Counterfactual MPS measure calculated assuming the exchange rate is in equilibrium with different exchange rate pass-through is also presented. It is shown that when no exchange rate pass-through to domestic prices occurs, the transfer of the indirect effect of exchange rate misalignment into the counterfactual MPS is full. But when there is exchange rate pass-through, even though partially, the transfer of indirect effect is significantly smaller.
Results based on the commodity-specific PSE show that the exchange rate effect also depends on the relative importance of different PSE components. In addition to a positive impact on the direct effects measured by commodity-specific PSE compared to those measured by commodity-specific MPS, the increasing share of budgetary expenditures in India's agricultural support in recent years has resulted in more pronounced indirect effects. For China, the exchange rate effects are more similar between the PSE and the MPS measures at the commodity level because of the dominance of the MPS component relative to the budgetary payments in the PSEs.
Moving from commodity-specific to aggregate measures, one can observe a similar pattern of agricultural support. However, the exchange rate effect measured by the total PSE appears to be more important: it becomes several times larger in magnitude than the direct effect in periods of severe exchange rate misalignment. The exchange rate effect when the PSE is "scaled up" from covered commodities to an estimate for the total agricultural sector is also demonstrated even though the assumption imposed by scaling-up may be unrealistic if price support is concentrated among those products included in the analysis. Since the commodity coverage in both countries tends to be incomplete and the scaling-up procedure leads to a total MPS component of greater magnitude, larger exchange rate effects are found in the scaled-up than the non-scaled-up version of the total PSEs. The impact of scaling-up on the indirect effect is proportional to the share of covered commodities in the total value of agricultural production. Again for the PSEs at both the commodity and aggregate levels, the counter factual measures indicate a full transfer of indirect effect of exchange rate when no exchange rate pass-through is assumed. A large portion of the indirect effect disappears when incomplete exchange rate pass-through is assumed resulting in a smaller transfer of the effect to the counter factual PSEs. / Ph. D.
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Aerodynamic Investigation of Upstream Misalignment over the Nozzle Guide Vane in a Transonic CascadeLee, Yeong Jin 06 June 2017 (has links)
The possibility of misalignments at interfaces would be increased due to individual parts' assembly and external factors during its operation. In actual engine representative conditions, the upstream misalignments have effects on turbines performance through the nozzle guide vane passages. The current experimental aerodynamic investigation over the nozzle guide vane passage was concentrated on the backward-facing step of upstream misalignments. The tests were performed using two types of vane endwall platforms in a 2D linear cascade: flat endwall and axisymmetric converging endwall. The test conditions were a Mach number of 0.85, Re_ex 1.5*10^6 based on exit condition and axial chord, and a high freestream turbulence intensity (16%), at the Virginia tech transonic cascade wind tunnel. The experimental results from the surface flow visualization and the five-hole probe measurements at the vane-passage exit were compared with the two cases with and without the backward-facing step for both types of endwall platforms.
As a main source of secondary flow, a horseshoe vortex at stagnation region of the leading edge of the vane directly influences other secondary flows. The intensity of the vortex is associated with boundary layer thickness of inlet flow. In this regard, the upstream backward-facing step as a misalignment induces the separation and attachment of the inlet flow sequentially, and these cause the boundary layer of the inlet flow to reform and become thinner locally. The upstream-step positively affects loss reduction in aerodynamics due to the thinner inlet boundary layer, which attenuates a horseshoe vortex ahead of the vane cascade despite the development of the additional vortices. And converging endwall results in an increase of the effect of the upstream misalignment in aerodynamics, since the inlet boundary layer becomes thinner near the vane's leading edge due to local flow acceleration caused by steep contraction of the converging endwall. These results show good correlation with many previous studies presented herein. / Master of Science
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Misalignment Effects of the Self-Tracking Laser Doppler VibrometerZima, Andrew David Jr. 12 May 2001 (has links)
There are many limitations to the current methods used to measure vibration on rotating structures. These limitations include physical flow blockages, relating the measurement spot to the structure rotation, data processing issues, and having to physically alter the engine. This work further describes aspects of a self-tracking laser vibrometry system that can be used to measure the vibrations of rotating structures. This method, if setup correctly, has the capability to overcome many of the limitations listed above. A study of all misalignment effects is presented in this thesis. The study consists of a parametric sensitivity analysis of misalignment variables, a parametric Monte Carlo analysis of misalignment variables, and a full interaction Monte Carlo analysis of misalignment variables. In addition, the results of the misalignment variable analyses were used to develop a self-tracker test rig for obtaining fan vibration from a Pratt and Whitney JT15D turbofan engine. A prototype this test rig was designed, built, and tested on the turbofan. It was found that in order to achieve acceptable amounts of position and velocity error using the self-tracker LDV system, very strict alignment of the optical equipment is necessary. Additionally, the alignment criteria can likely be achieved with the use of digitally controlled high precision linear motion equipment. / Master of Science
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Organizational Learning and Project Portfolio Success : An Empirical Study in a Multinational Oil and Gas CompanyPutri, Autie Minati, Al Hadla, Mostafa January 2016 (has links)
This study aims to understand the impact of organizational learning on project portfolio success in a multinational Oil and Gas company operated in Indonesia. The Organizational Learning and Project Portfolio Success have been proven to have contribution to business performance and they might possess a relationship where enhancing one of them will strengthen the other. Exploring on this relationship might give beneficial input to the organization in order to maximize their success. Thus, our research question is formulated as: To what extent does Organizational Learning impact the Project Portfolio Success? We developed the study’s conceptual model based on the relevant previous literature. The conceptual model depicted the aim of the study to test the potential positive impact of each Learning Stocks (Individual, Group, and Organizational) on Project Portfolio Success, as well as the aim to test the potential negative impact of the misalignment between Learning Stocks and Learning Flows on Project Portfolio Success in the studied company. We adopted quantitative research method due to the nature of research question and the ontological and epistemological assumptions we hold toward the studied phenomena. Accordingly, we used a questionnaire as an instrument to collect the required data to test the hypotheses. The questionnaire was subject to a pilot test to ensure the clarity of statements before it was distributed to the targeted respondents which are the managers and the Project Management Office personnel in the studied company. The research hypotheses were tested by applying single and multi-regression analyses using SPSS software. Our findings showed that, independently, each learning stock type (Individual, Group and organizational) has a significant positive impact to project portfolio success. When we looked for the best model that gives the highest explanatory power, the result showed that the combination of all three learning stocks in one model can explain project portfolio success construct the most. Lastly, the study proved that the misalignment between learning stocks and flows gives negative impact to the project portfolio success. We concluded the study by stating the theoretical contribution and practical recommendations based on the results such as the need to have a balanced investment in the individual, group and organizational learning stocks; ensure the alignment between the organizational units’ strategies and goals; develop an “Internal Strategy Awareness Index”; and conduct a revision of the alignment between the company’s strategy and the project portfolio.
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Směnné kurzy během globální krize: role fundamentálních ukazatelů / Exchange Rates in the Global Crisis: the Role of FundamentalsRůžičková, Pavla January 2011 (has links)
This thesis studies the equilibrium real effective exchange rates and the degree of misalignment of currencies. It focuses on the real effective exchange rates of Icelandic króna and Chinese renminbi, with special attention paid to the evolution of these exchange rates in the period of crisis. It identifies key factors influencing the real effective exchange rates of króna and renminbi, calculates their equilibrium level and confirms that these currencies were misaligned in the pre-crisis period. It stresses the impact of real interest rate differential in the case of króna and of sterilization operations applied by the People's Bank of China in the case of renminbi. It further examines whether the relationship between real exchange rates and economic fundamentals was distorted in the crisis. Finally, the thesis provides an insight into whether the crisis led to narrowing the degree of misalignment of renminbi and króna.
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Anomaly Detection for Machine Diagnostics : Using Machine learning approach to detect motor faults / Anomalidetektion för maskindiagnostikMeszaros, Christopher, Wärn, Fabian January 2019 (has links)
Machine diagnostics is usually done via conditioned monitoring (CM). This approach analyses certain thresholds or patterns for diagnostic purposes. This approach can be costly and time consuming for industries. A larger downside is the difficulty in generalizing CM to a wider set of machines.There is a new trend of using a Machine learning (ML) approach to diagnose machines states. An ML approach would implement an autonomous system for diagnosing machines. It is highly desirable within industry to replace the manual labor performed when setting up CBM systems. Often the ML algorithms chosen are novelty/anomaly based. It is a popular hypothesis that detecting anomalous measurements from a system is a natural byproduct of a machine in a faulty state.The purpose of this thesis is to help CombiQ with an implementation strategy for a fault detection system. The idea of the fault detection system is to make prediction outcomes for machines within the system. More specifically, the prediction will inform whether a machine is in a faulty state or a normal state. An ML approach will be implemented to predict anomalous measurements that corresponds to a faulty state. The system will have no previous data on the machines. However, data for a machine will be acquired once sensors (designed by CombiQ) have been set up for the machine.The results of the thesis proposes an unsupervised and semi-supervised approach for creating the ML models used for the fault detection system. The unsupervised approach will rely on assumptions when selecting the hyperparameters for the ML. The semi-supervised approach will try to learn the hyperparameters through cross validation and grid search. An experiment was set up check whether three ML algorithms can learn optimal hyperparameter values for predicting rotational unbalance. The algorithm known as OneClassVM showed the best precision results and hence proved more useful for CombiQ’s criterium.
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