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This handbook describes a framework for development, validation, and integration of multipurpose simulation models. The presented methodology enables reuse of models in different applications with different purposes. The scope is simulation models representing physical environment, physical aircraft systems or subsystems, avionics equipment, and electronic hardware. The methodology has been developed by a small interdisciplinary team, with experience from Modeling and Simulation (M&S) of vehicle systems as well as development of simulators for verification and training. Special care has been taken to ensure usability of the workflow and method descriptions, mainly by means of 1) a user friendly format, easy to overview and update, 2) keeping the amount of text on an appropriate level, and 3) providing relevant examples, templates, and checklists. A simulation model of an aircraft Environmental Control System (ECS) is used as an example to guide the reader through the workflow of developing and validating multipurpose simulation models

An Experimental Study of Sex Segregation in the Swedish Labour Market: Is Discrimination the Explanation?

This paper studies whether sex discrimination is the cause of sex segregation in the Swedish labour market. The correspondence testing (CT) method was used, which entails two qualitatively identical applications, one with a female name and one with a male name, being sent to employers advertising for labour. The results show that females have a somewhat higher callback rate to interview in female-dominated occupations, while in male-dominated occupations there is no evidence of any difference. The conclusion is that the sex segregation prevailing in the Swedish labour market cannot be explained by discrimination in hiring. Instead, the explanation must be found on the supply side.sex discrimination, segregation, exit from unemployment

Is It Your Foreign Name or Foreign Qualifications? An Experimental Study of Ethnic Discrimination in Hiring

This paper contributes to the existing literature on ethnic discrimination of immigrants in hiring by addressing the central question of what employers act on in a job application. The method involved sending qualitatively identical resumes signalling belonging to different ethnic groups to firms advertising for labour. The results show that whether the applicant has a native sounding or a foreign sounding name explains approximately 77 per cent of the total gap in the probability of being invited to an interview between natives and immigrants, while having foreign qualifications only explains the remaining 23 per cent. This in turn, suggests a lower bound for statistical discrimination of approximately 23 per cent of total discrimination. The analysis indicates further that the 77 per cent are most likely driven by a mixture of preference-based and statistical discrimination.statistical discrimination, ethnic discrimination, hiring, job search, preference-based discrimination, correspondence testing

Employer Attitudes, the Marginal Employer and the Ethnic Wage Gap

Ethnic minorities have lower wages compared to the ethnic majority in most EU-countries. However, to what extent these wage gaps are the result of prejudice toward ethnic minority workers is virtually unknown. This study sets out to examine what role prejudice play in the creation of the ethnic wage gap in one of Europe's most egalitarian countries, Sweden. The analysis takes into account the important distinction between average employer attitudes and the attitude of the marginal employer. Our results confirm that the attitudes of the marginal employer – but not those of the average employer – are important for the ethnic wage gap. This relationship becomes even stronger when potential measurement error and other forms of endogeneity are accounted for by controlling for a rich set of variables and implementing instrumental variable techniques.attitudes, prejudice, marginal employer, ethnic wage gap

Development of Numerical Methods for Accurate and Efficient Scale-Resolving Simulations

Hybrid RANS (Reynolds-Averaged Navier-Stokes)-LES (Large-Eddy Simulation) techniques are considered to be sufficiently accurate and computationally affordable for the aeronautical industry. Scale-resolving simulations is a powerful tool that can accurately predict complex unsteady compressible high-Reynolds-number turbulent flows, as often encountered aeronautical applications. However, since the turbulent scales are resolved instead of modeled, higher demand is placed on the underlying numerical methods used in the simulations.This thesis explores and develops numerical methods suitable for hybrid RANS-LES. The methods are implemented in the Computational Fluid Dynamics (CFD) solver M-Edge, a compressible unstructured node-centered edge-based solver. A low-dissipative, low-dispersive numerical scheme was calibrated and verified in LES of turbulent channel flow and Decaying Homogeneous Isotropic Turbulent (DHIT). It was shown that numerical dissipation and dispersion needs to be carefully tuned, in order to accurately predict resolved turbulent stresses and the correct decay of turbulent kinetic energy. The reported results are in good agreement with reference DNS and experimental data.The optimized numerical scheme was then applied to simulate developing hybrid RANS-LES turbulent channel flow. In order to mitigate the grey area region in the LES zone, a Synthetic Turbulence Generator (STG) was applied at the RANS-LES interface. It was shown that using upstream turbulent statistics from a precursor LES or RANS, the recovery length of the skin friction coefficient could be reduced to just a few boundary layer thicknesses.A new implicit gradient reconstruction scheme suitable for node-centered solvers was proposed. It was shown that the reconstruction scheme achieves fourth-order scaling on regular grids and third-order scaling on irregular grid for an analytical academic case. The Navier-Stokes Characteristic Boundary Condition (NSCBC) was implemented and verified for transport of an analytical vortex. It was shown that special boundary treatment is needed for transporting turbulent structures through the boundary with minimal reflections

Tracing and Explaining Execution of CLP(FD) Programs

Previous work in the area of tracing CLP(FD) programs mainly focuses on providing information about control of execution and domain modification. In this paper, we present a trace structure that provides information about additional important aspects. We incorporate explanations in the trace structure, i.e. reasons for why certain solver actions occur. Furthermore, we come up with a format for describing the execution of the filtering algorithms of global constraints. Some new ideas about the design of the trace are also presented. For example, we have modeled our trace as a nested block structure in order to achieve a hierarchical view. Also, new ways about how to represent and identify different entities such as constraints and domain variables are presented.Comment: 16 pages; Alexandre Tessier, editor; WLPE 2002, http://xxx.lanl.gov/abs/cs.SE/020705

Predictability modulates the affective and sensory-discriminative neural processing of pain

Knowing what is going to happen next, that is, the capacity to predict upcoming events, modulates the extent to which aversive stimuli induce stress and anxiety. We explored this issue by manipulating the temporal predictability of aversive events by means of a visual cue, which was either correlated or uncorrelated with pain stimuli (electric shocks). Subjects reported lower levels of anxiety, negative valence and pain intensity when shocks were predictable. In addition to attenuate focus on danger, predictability allows for correct temporal estimation of, and selective attention to, the sensory input. With functional magnetic resonance imaging, we found that predictability was related to enhanced activity in relevant sensory-discriminative processing areas, such as the primary and secondary sensory cortex and posterior insula. In contrast, the unpredictable more aversive context was correlated to brain activity in the anterior insula and the orbitofrontal cortex, areas associated with affective pain processing. This context also prompted increased activity in the posterior parietal cortex and lateral prefrontal cortex that we attribute to enhanced alertness and sustained attention during unpredictability. (c) 2006 Elsevier Inc. All rights reserved.This study was supported by grants from The Swedish Research Council (2003-5810), The family Hedlund Foundation and Karolinska Institutet. The project was finished in the context of Stockholm Brain Institute.info:eu-repo/semantics/publishedVersio

Sources of errors in time domain refloctometry measurements of soil moisture

In the monitoring of soil water Time-Domain Reflectometry (TDR) has gained widespread use. TDR has proved to be useful both in determination of soil water content and soil bulk electrical conductivity. These measurements are, however, complex and there are many sources of errors to consider. The purpose of this investigation is therefore to identify errors, the causes of these errors and to suggest improvements. This was achieved by a literature study as well as by two experiments, one conducted in the field and one conducted in the laboratory. Four TDR-systems were tested. The results show that errors can be classified in two groups, errors which is influencing the determination of the dielectric constant, Ka, and errors affecting the conversion of Ka to volumetric water content, θν. The former type can be further divided into errors which concern the quality of the trace and errors influencing the evaluation of the trace. Unbalanced probes and long cables were identified as contributing to uncertainties. Errors from conversion of Ka to θν were considered when the systems were calibrated. One of the programs tested allows convenient one point calibration with a trace offset parameter. The advantage of re-evaluation of measurements with individual settings also permits increased accuracy of measurements

Towards Improved Scale-Resolving Modeling and Simulations of Turbulent Flows

Scale-resolving simulations are viewed as powerful means for predicting complex turbulent flows, as often encountered in aeronautical applications. However, since turbulent scales span over a considerable range from the smallest Kolmogorov scales to the largest of equivalence to configuration size, scale-resolving computations are often demanding on computational resources and, furthermore, on the underlying numerical methods used in the simulations. Nonetheless, hybrid RANS (Reynolds-Averaged Navier-Stokes)-LES (Large-Eddy Simulation) techniques are considered computationally accurate and affordable for aeronautical industry applications. This thesis explores and develops numerical methods suitable for hybrid RANS-LES. These methods are implemented in the Computational Fluid Dynamics (CFD) solver M-Edge