946 resultados para minimum order observers
Resumo:
Selleri's arguments that a consideration of noninertial reference frames in the framework of special relativity identify absolute simultaneity as being Nature's choice of synchronization are considered. In the case of rectilinearly accelerating rockets, it is argued by considering two rockets which maintain a fixed proper separation rather than a fixed separation relative to the inertial frame in which they start from rest, that what seems the most natural choice for a simultaneity convention is problem-dependent and that Einstein's definition is the most natural (though still conventional) choice in this case. In addition, the supposed problems special relativity has with treating a rotating disk, namely how a pulse of light traveling around the circumference of the disk can have a local speed of light equal to c everywhere but a global speed not equal to c, and how coordinate transformations to the disk can give the Lorentz transformations in the limit of large disk radius but small angular velocity, are addressed. It is shown that the theory of Fermi frames solves both of these problems. It is also argued that the question of defining simultaneity relative to a uniformly rotating disk does riot need to be resolved in order to resolve Ehrenfest's paradox.
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PURPOSE. To investigate the effect of age on optokinetic nystagmus (OKN) in response to stimuli designed to preferentially stimulate the M-pathway. METHOD. OKN was recorded in 10 younger (32.3 +/- 5.98 years) and 10 older (65.6 +/- 6.53) subjects with normal vision. Vertical gratings of 0.43 or 1.08 cpd drifting at 5 degrees/s or 20 degrees/s and presented at either 8% or 80% contrast were displayed on a large screen as full-field stimulation, central stimulation within a central Gaussian-blurred window of 15 diameter, or peripheral stimulation outside this window. All conditions apart from the high-contrast condition were presented in a random order at two light levels, mesopic (1.8 cdm(-2)) and photopic (71.5 cdm(-2)). RESULTS. Partial-field data indicated that central stimulation, mesopic light levels, and lower temporal frequency each significantly increased slow-phase velocity (SPV). Although there was no overall difference between groups for partial-field stimulation, full-field stimulation, or low-contrast stimulation, a change in illumination revealed a significant interaction with age: there was a larger decrease in SPV going from photopic to mesopic conditions for the older group than the younger group, especially for higher temporal frequency stimulation. CONCLUSIONS. OKN becomes reflexive in conditions conducive to M-pathway stimulation, and this rOKN response is significantly diminished in older healthy adults than in younger healthy adults, indicative of decreased M-pathway sensitivity.
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AMS subject classification: 49J52, 90C30.
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This research is motivated by the need for considering lot sizing while accepting customer orders in a make-to-order (MTO) environment, in which each customer order must be delivered by its due date. Job shop is the typical operation model used in an MTO operation, where the production planner must make three concurrent decisions; they are order selection, lot size, and job schedule. These decisions are usually treated separately in the literature and are mostly led to heuristic solutions. The first phase of the study is focused on a formal definition of the problem. Mathematical programming techniques are applied to modeling this problem in terms of its objective, decision variables, and constraints. A commercial solver, CPLEX is applied to solve the resulting mixed-integer linear programming model with small instances to validate the mathematical formulation. The computational result shows it is not practical for solving problems of industrial size, using a commercial solver. The second phase of this study is focused on development of an effective solution approach to this problem of large scale. The proposed solution approach is an iterative process involving three sequential decision steps of order selection, lot sizing, and lot scheduling. A range of simple sequencing rules are identified for each of the three subproblems. Using computer simulation as the tool, an experiment is designed to evaluate their performance against a set of system parameters. For order selection, the proposed weighted most profit rule performs the best. The shifting bottleneck and the earliest operation finish time both are the best scheduling rules. For lot sizing, the proposed minimum cost increase heuristic, based on the Dixon-Silver method performs the best, when the demand-to-capacity ratio at the bottleneck machine is high. The proposed minimum cost heuristic, based on the Wagner-Whitin algorithm is the best lot-sizing heuristic for shops of a low demand-to-capacity ratio. The proposed heuristic is applied to an industrial case to further evaluate its performance. The result shows it can improve an average of total profit by 16.62%. This research contributes to the production planning research community with a complete mathematical definition of the problem and an effective solution approach to solving the problem of industry scale.
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Perception of simultaneity and temporal order is studied with simultaneity judgment (SJ) and temporal-order judgment (TOJ) tasks. In the former, observers report whether presentation of two stimuli was subjectively simultaneous; in the latter, they report which stimulus was subjectively presented first. SJ and TOJ tasks typically give discrepant results, which has prompted the view that performance is mediated by different processes in each task. We looked at these discrepancies from a model that yields psychometric functions whose parameters characterize the timing, decisional, and response processes involved in SJ and TOJ tasks. We analyzed 12 data sets from published studies in which both tasks had been used in within-subjects designs, all of which had reported differences in performance across tasks. Fitting the model jointly to data from both tasks, we tested the hypothesis that common timing processes sustain simultaneity and temporal order judgments, with differences in performance arising from task-dependent decisional and response processes. The results supported this hypothesis, also showing that model psychometric functions account for aspects of SJ and TOJ data that classical analyses overlook. Implications for research on perception of simultaneity and temporal order are discussed.
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Research on temporal-order perception uses temporal-order judgment (TOJ) tasks or synchrony judgment (SJ) tasks in their binary SJ2 or ternary SJ3 variants. In all cases, two stimuli are presented with some temporal delay, and observers judge the order of presentation. Arbitrary psychometric functions are typically fitted to obtain performance measures such as sensitivity or the point of subjective simultaneity, but the parameters of these functions are uninterpretable. We describe routines in MATLAB and R that fit model-based functions whose parameters are interpretable in terms of the processes underlying temporal-order and simultaneity judgments and responses. These functions arise from an independent-channels model assuming arrival latencies with exponential distributions and a trichotomous decision space. Different routines fit data separately for SJ2, SJ3, and TOJ tasks, jointly for any two tasks, or also jointly for the three tasks (for common cases in which two or even the three tasks were used with the same stimuli and participants). Additional routines provide bootstrap p-values and confidence intervals for estimated parameters. A further routine is included that obtains performance measures from the fitted functions. An R package for Windows and source code of the MATLAB and R routines are available as Supplementary Files.
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Research on the perception of temporal order uses either temporal-order judgment (TOJ) tasks or synchrony judgment (SJ) tasks, in both of which two stimuli are presented with some temporal delay and observers must judge the order of presentation. Results generally differ across tasks, raising concerns about whether they measure the same processes. We present a model including sensory and decisional parameters that places these tasks in a common framework that allows studying their implications on observed performance. TOJ tasks imply specific decisional components that explain the discrepancy of results obtained with TOJ and SJ tasks. The model is also tested against published data on audiovisual temporal-order judgments, and the fit is satisfactory, although model parameters are more accurately estimated with SJ tasks. Measures of latent point of subjective simultaneity and latent sensitivity are defined that are invariant across tasks by isolating the sensory parameters governing observed performance, whereas decisional parameters vary across tasks and account for observed differences across them. Our analyses concur with other evidence advising against the use of TOJ tasks in research on perception of temporal order.
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A Minimum Essential Standard of Living (MESL) is derived from a negotiated consensus on what people believe is a minimum standard. It is a standard of living that meets an individual’s or a household’s physical, psychological and social needs. This is calculated by identifying the goods and services required by different household types in order to meet their needs. While an MESL is based on needs, not wants, it is a standard of living below which nobody should be expected to live. This report focuses on food, one of the 16 elements of the Minimum Essential Standard of Living (MESL) data. It is based on a methodology called Consensual Budget Standards (CBS). The report is presented in the context of increasing concerns about the issue of food poverty in the Republic of Ireland (ROI) and an increase in the number of people reporting that they do not have enough money to buy food. Recent data from The Organisation for Economic Co-operation and Development (OECD) have shown that the number of people believing they cannot afford food doubled from 4.2% in 2008 to 9% in 2014. Data from Eurostat show that in 2013, food and non-alcoholic beverage prices in Ireland were 17% higher than the EU average. Moreover, research by Carney and Maitre, using data from the Survey on Income and Living Conditions (SILC), found that one in ten people are living in food poverty in Ireland. Food poverty is defined as the inability to have an adequate and nutritious diet due to issues of affordability and access to food. This has related effects on health, culture and social participation. The 2013 data from the Survey on Income and Living Conditions (SILC) show that 1.4 million people, almost 31% of the population, suffer from deprivation. This means that they are unable to afford two items from a list of 11 very basic items (of which one is not being able to eat a meal with meat, chicken, fish or a vegetarian equivalent every second day). The highest levels of deprivation are experienced by lone parents (63%), unemployed people (55%) and people not at work because of illness or disability (53%). The experience of the Vincentian Partnership for Social Justice (VPSJ) is that expenditure on food tends to be one of the least important considerations when households are dealing with competing demands on an inadequate income. A Minimum Essential Standard of Living (MESL) is derived from a negotiated consensus on what people believe is a minimum standard. It is a standard of living that meets an individual’s or a household’s physical, psychological and social needs. This is calculated by identifying the goods and services required by different household types in order to meet their needs. While an MESL is based on needs, not wants, it is a standard of living below which nobody should be expected to live. This report focuses on food, one of the 16 elements of the Minimum Essential Standard of Living (MESL) data. It is based on a methodology called Consensual Budget Standards (CBS). The report is presented in the context of increasing concerns about the issue of food poverty in the Republic of Ireland (ROI) and an increase in the number of people reporting that they do not have enough money to buy food. Recent data from The Organisation for Economic Co-operation and Development (OECD) have shown that the number of people believing they cannot afford food doubled from 4.2% in 2008 to 9% in 2014. Data from Eurostat show that in 2013, food and non-alcoholic beverage prices in Ireland were 17% higher than the EU average. Moreover, research by Carney and Maitre, using data from the Survey on Income and Living Conditions (SILC), found that one in ten people are living in food poverty in Ireland. Food poverty is defined as the inability to have an adequate and nutritious diet due to issues of affordability and access to food. This has related effects on health, culture and social participation. The 2013 data from the Survey on Income and Living Conditions (SILC) show that 1.4 million people, almost 31% of the population, suffer from deprivation. This means that they are unable to afford two items from a list of 11 very basic items (of which one is not being able to eat a meal with meat, chicken, fish or a vegetarian equivalent every second day). The highest levels of deprivation are experienced by lone parents (63%), unemployed people (55%) and people not at work because of illness or disability (53%). The experience of the Vincentian Partnership for Social Justice (VPSJ) is that expenditure on food tends to be one of the least important considerations when households are dealing with competing demands on an inadequate income. - See more at: http://www.safefood.eu/Publications/Research-reports/The-cost-of-a-healthy-food-basket.aspx#sthash.RiBpj5no.dpuf A Minimum Essential Standard of Living (MESL) is derived from a negotiated consensus on what people believe is a minimum standard. It is a standard of living that meets an individual’s or a household’s physical, psychological and social needs. This is calculated by identifying the goods and services required by different household types in order to meet their needs. While an MESL is based on needs, not wants, it is a standard of living below which nobody should be expected to live. This report focuses on food, one of the 16 elements of the Minimum Essential Standard of Living (MESL) data. It is based on a methodology called Consensual Budget Standards (CBS). The report is presented in the context of increasing concerns about the issue of food poverty in the Republic of Ireland (ROI) and an increase in the number of people reporting that they do not have enough money to buy food. Recent data from The Organisation for Economic Co-operation and Development (OECD) have shown that the number of people believing they cannot afford food doubled from 4.2% in 2008 to 9% in 2014. Data from Eurostat show that in 2013, food and non-alcoholic beverage prices in Ireland were 17% higher than the EU average. Moreover, research by Carney and Maitre, using data from the Survey on Income and Living Conditions (SILC), found that one in ten people are living in food poverty in Ireland. Food poverty is defined as the inability to have an adequate and nutritious diet due to issues of affordability and access to food. This has related effects on health, culture and social participation. The 2013 data from the Survey on Income and Living Conditions (SILC) show that 1.4 million people, almost 31% of the population, suffer from deprivation. This means that they are unable to afford two items from a list of 11 very basic items (of which one is not being able to eat a meal with meat, chicken, fish or a vegetarian equivalent every second day). The highest levels of deprivation are experienced by lone parents (63%), unemployed people (55%) and people not at work because of illness or disability (53%). The experience of the Vincentian Partnership for Social Justice (VPSJ) is that expenditure on food tends to be one of the least important considerations when households are dealing with competing demands on an inadequate income. - See more at: http://www.safefood.eu/Publications/Research-reports/The-cost-of-a-healthy-food-basket.aspx#sthash.RiBpj5no.dpuf A Minimum Essential Standard of Living (MESL) is derived from a negotiated consensus on what people believe is a minimum standard. It is a standard of living that meets an individual’s or a household’s physical, psychological and social needs. This is calculated by identifying the goods and services required by different household types in order to meet their needs. While an MESL is based on needs, not wants, it is a standard of living below which nobody should be expected to live. This report focuses on food, one of the 16 elements of the Minimum Essential Standard of Living (MESL) data. It is based on a methodology called Consensual Budget Standards (CBS). The report is presented in the context of increasing concerns about the issue of food poverty in the Republic of Ireland (ROI) and an increase in the number of people reporting that they do not have enough money to buy food. Recent data from The Organisation for Economic Co-operation and Development (OECD) have shown that the number of people believing they cannot afford food doubled from 4.2% in 2008 to 9% in 2014. Data from Eurostat show that in 2013, food and non-alcoholic beverage prices in Ireland were 17% higher than the EU average. Moreover, research by Carney and Maitre, using data from the Survey on Income and Living Conditions (SILC), found that one in ten people are living in food poverty in Ireland. Food poverty is defined as the inability to have an adequate and nutritious diet due to issues of affordability and access to food. This has related effects on health, culture and social participation. The 2013 data from the Survey on Income and Living Conditions (SILC) show that 1.4 million people, almost 31% of the population, suffer from deprivation. This means that they are unable to afford two items from a list of 11 very basic items (of which one is not being able to eat a meal with meat, chicken, fish or a vegetarian equivalent every second day). The highest levels of deprivation are experienced by lone parents (63%), unemployed people (55%) and people not at work because of illness or disability (53%). The experience of the Vincentian Partnership for Social Justice (VPSJ) is that expenditure on food tends to be one of the least important considerations when households are dealing with competing demands on an inadequate income. - See more at: http://www.safefood.eu/Publications/Research-reports/The-cost-of-a-healthy-food-basket.aspx#sthash.RiBpj5no.dpuf
Resumo:
The selection of the optimal operating conditions for an industrial acrylonitrile recovery unit was conducted by the systematic application of the response surface methodology, based on the minimum energy consumption and products specifications as process constraints. Unit models and plant simulation were validated against operating data and information. A sensitivity analysis was carried out in order to identify the set of parameters that strongly affect the trajectories of the system while keeping products specifications. The results suggest that energy savings of up to 10% are possible by systematically adjusting operating conditions.
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This thesis focuses on the investigation and the implementation of different observers for the estimation of the roll angle of a motorbike. The central core of the activity is applying a Model-Based design in order to outline, simulate and implement the filters with the aim of a final comparison of the performances. This approach is crucially underlined among the chapters that articulate this document: first the design and tuning of an Extended Kalman Filter and a Complementary Filter in a pure simulation environment emphasize the most accurate choice for the particular problem. After this, several steps were performed in order to move from the aforementioned simulation environment to a real hardware application. In conclusion, several sensor configurations were tested and compared in order to highlight which sensor suite gives the best performances.
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This thesis work has been motivated by an internal benchmark dealing with the output regulation problem of a nonlinear non-minimum phase system in the case of full-state feedback. The system under consideration structurally suffers from finite escape time, and this condition makes the output regulation problem very hard even for very simple steady-state evolution or exosystem dynamics, such as a simple integrator. This situation leads to studying the approaches developed for controlling Non-minimum phase systems and how they affect feedback performances. Despite a lot of frequency domain results, only a few works have been proposed for describing the performance limitations in a state space system representation. In particular, in our opinion, the most relevant research thread exploits the so-called Inner-Outer Decomposition. Such decomposition allows splitting the Non-minimum phase system under consideration into a cascade of two subsystems: a minimum phase system (the outer) that contains all poles of the original system and an all-pass Non-minimum phase system (the inner) that contains all the unavoidable pathologies of the unstable zero dynamics. Such a cascade decomposition was inspiring to start working on functional observers for linear and nonlinear systems. In particular, the idea of a functional observer is to exploit only the measured signals from the system to asymptotically reconstruct a certain function of the system states, without necessarily reconstructing the whole state vector. The feature of asymptotically reconstructing a certain state functional plays an important role in the design of a feedback controller able to stabilize the Non-minimum phase system.
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Latency can be defined as the sum of the arrival times at the customers. Minimum latency problems are specially relevant in applications related to humanitarian logistics. This thesis presents algorithms for solving a family of vehicle routing problems with minimum latency. First the latency location routing problem (LLRP) is considered. It consists of determining the subset of depots to be opened, and the routes that a set of homogeneous capacitated vehicles must perform in order to visit a set of customers such that the sum of the demands of the customers assigned to each vehicle does not exceed the capacity of the vehicle. For solving this problem three metaheuristic algorithms combining simulated annealing and variable neighborhood descent, and an iterated local search (ILS) algorithm, are proposed. Furthermore, the multi-depot cumulative capacitated vehicle routing problem (MDCCVRP) and the multi-depot k-traveling repairman problem (MDk-TRP) are solved with the proposed ILS algorithm. The MDCCVRP is a special case of the LLRP in which all the depots can be opened, and the MDk-TRP is a special case of the MDCCVRP in which the capacity constraints are relaxed. Finally, a LLRP with stochastic travel times is studied. A two-stage stochastic programming model and a variable neighborhood search algorithm are proposed for solving the problem. Furthermore a sampling method is developed for tackling instances with an infinite number of scenarios. Extensive computational experiments show that the proposed methods are effective for solving the problems under study.
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Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y=0) are reported in sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton dv1/dy|y=0 changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.
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Harmony is one of the main objectives in surgical and orthodontic treatment and this harmony must be present in the smile, as well as in the face. The aim of the present study was to assess the perceptions of professionals and laypersons in relation to the harmony of the smile of patients with or without vertical maxillary alterations. Sixty observers (oral and maxillofacial surgeons, orthodontists and laypersons) reported the degree of harmony of six smiles using an objective questionnaire and the participants indicated if there was a need for corrective surgery or not. The classification of observers was recorded on a Likert scale from 1 to 5. Mixed regression was used to determine differences between the three groups. Statistically significant differences were found only for the harmony of the smile between the oral and maxillofacial surgeons and laypersons, with laypersons being more critical when assessing the smile. There was no statistical difference between the other groups for the harmony of the smile or the indication of corrective surgery. The patterns of greater or lesser harmony determined by observers during the smile were similar to those found in the literature as the ideal standard in relation to vertical maxillary positioning. Laypersons had a tendency to be more critical in relation to facial harmony than surgeons, although no statistical differences were found in the other groups in relation to the harmony of the smile or indication for the corrective surgery. In addition, the patterns of greater or lesser harmony of the smile determined by the participants were similar to those found in the literature as the ideal standard in relation to vertical maxillary positioning. Overall, the present study demonstrates that adequate interaction between surgeons, orthodontists and laypersons is essential in order to achieve facial harmony with orthodontic and/or surgical treatment. Opinion of specialists and laypersons about the smile in relation to the vertical positioning of the maxilla.