All-regime Lagrangian-Remap numerical schemes for the gas dynamics equations. Applications to the large friction and low Mach coefficients

In this talk, we propose an all regime Lagrange-Projection like numerical scheme for the gas dynamics equations. By all regime, we mean that the numerical scheme is able to compute accurate approximate solutions with an under-resolved discretization with respect to the Mach number M, i.e. such that the ratio between the Mach number M and the mesh size or the time step is small with respect to 1. The key idea is to decouple acoustic and transport phenomenon and then alter the numerical flux in the acoustic approximation to obtain a uniform truncation error in term of M. This modified scheme is conservative and endowed with good stability properties with respect to the positivity of the density and the internal energy. A discrete entropy inequality under a condition on the modification is obtained thanks to a reinterpretation of the modified scheme in the Harten Lax and van Leer formalism. A natural extension to multi-dimensional problems discretized over unstructured mesh is proposed. Then a simple and efficient semi implicit scheme is also proposed. The resulting scheme is stable under a CFL condition driven by the (slow) material waves and not by the (fast) acoustic waves and so verifies the all regime property. Numerical evidences are proposed and show the ability of the scheme to deal with tests where the flow regime may vary from low to high Mach values.

Map of Tiber Creek, from its mouth to the extent of tide water : [Washington D.C.].

Covers area now occupied by the Mall.

The platt of Safford [i.e. Stafford] from the mouth of upper Machotich to the mouth of Chappawamsick /

Pen-and-ink on tracing paper, mounted on cloth.

Location dependence of a MEMS electromagnetic transducer with respect to an AC power source

A MEMS, silicon based device with a cantilever oscillationsand an integrated magnet is presented for magnetic to electrical transduction. The cantilever structure can be configured either as an energy harvester to harvest power from an AC power line or as an AC current sensor. The positioning of the transducer with respect to the AC conductor is critical in both scenarios. For the energy scavenger, correct positioning is required to optimize the harvested power. For the current sensor, it is necessary to optimise the sensitivity of the sensor. This paper considers the effect of the relative position of the transducer with respect to the wire on the resulting electromagnetic forces and torques driving the device. It is shown here that the magnetic torque acting on a cantilever beam with an integrated magnet and in the vicinity of an alternating electromagnetic field is a very significant driver of the cantilever oscillations.

Distributed Large-scale Mixed-Integer Optimization with Application to Energy and Multi-robot Networks

Several decision and control tasks in cyber-physical networks can be formulated as large- scale optimization problems with coupling constraints. In these "constraint-coupled" problems, each agent is associated to a local decision variable, subject to individual constraints. This thesis explores the use of primal decomposition techniques to develop tailored distributed algorithms for this challenging set-up over graphs. We first develop a distributed scheme for convex problems over random time-varying graphs with non-uniform edge probabilities. The approach is then extended to unknown cost functions estimated online. Subsequently, we consider Mixed-Integer Linear Programs (MILPs), which are of great interest in smart grid control and cooperative robotics. We propose a distributed methodological framework to compute a feasible solution to the original MILP, with guaranteed suboptimality bounds, and extend it to general nonconvex problems. Monte Carlo simulations highlight that the approach represents a substantial breakthrough with respect to the state of the art, thus representing a valuable solution for new toolboxes addressing large-scale MILPs. We then propose a distributed Benders decomposition algorithm for asynchronous unreliable networks. The framework has been then used as starting point to develop distributed methodologies for a microgrid optimal control scenario. We develop an ad-hoc distributed strategy for a stochastic set-up with renewable energy sources, and show a case study with samples generated using Generative Adversarial Networks (GANs). We then introduce a software toolbox named ChoiRbot, based on the novel Robot Operating System 2, and show how it facilitates simulations and experiments in distributed multi-robot scenarios. Finally, we consider a Pickup-and-Delivery Vehicle Routing Problem for which we design a distributed method inspired to the approach of general MILPs, and show the efficacy through simulations and experiments in ChoiRbot with ground and aerial robots.

Sexualidade e saúde mental: construindo sentidos entre pessoas usuárias de um CAPS

When expressed by mental health services users, sexuality is typically denied by professionals, viewed as another symptom or as if these people are not capable of practicing it. Once Brazilian health professionals haven’t shown lots of investment in this theme, and few are the studies in this field, it is necessary the attention to be focused on researches involving this public. Therefore, the main goal of this study was understand the meanings of sexuality of the mental health services users, which were negotiated in sexuality workshops. The secondary goals were: a) understand the meanings of themes about sexuality brought by users through their experiences of everyday life; b) to evaluate the facilitating experience of the workshops on sexuality at CAPS. Thus, 10 workshops on sexuality were held, with an average of an hour and twenty minutes each, distributed from December 2014 and April 2015. There were 43 participants, 29 women and 14 men. The meetings had the following central themes: sexuality; sexuality and mental health; myths, beliefs and sexual taboos; gender identity; sexual orientation; sexual and reproductive rights; safe sex; and STD/AIDS. The data collection was through audio-recording of these meetings. Later, was made the transcript of the workshops, a careful reading of these transcripts and then its analysis. It was identified categories to analyze the interfaces that permeate the focus of the study. Initially, the categories relating to mental health and sexuality: meanings about sexuality; gender issues; gender and religion; sexual rights, STD/AIDS prevention and attention or denial of sexuality at CAPS. Later, those relating to the workshops facilitating process: challenges in facilitating the workshops; and the perception of the participants. A variety of meanings about sexuality could be noticed in the users’ statements, relating it more with affection and respect than with intercourse. The gender issues that emerged during the workshops were related to marital relationship, sexism, domestic violence, psychological violence and male and female roles in society. Moreover, were also revealed some situations that associated gender differences with religious issues, such as the submission of women and homosexuality. It was also noticed some experiences of the participants involving worrying situations of family violence, suicidal ideation and chemical castration, were often mismanaged or ignored by the service professionals. With regard to the facilitation of the workshops, it was possible to legitimize it as places where users were able to talk openly about the suggested themes and highlight its importance to the study site. Besides, it’s possible to list a few challenges of its facilitation in a mental health service, which was in general positively evaluated by the participants. Thus, the research highlights the need for sexuality theme discussion in mental health services, in order to understand, discuss and inform the users. Also, it’s important to problematize the stigma created in the theme relation with the users, the professionals and the society, working its specificities and avoiding a pathological bias.

Teoria do valor e trabalho produtivo no setor de serviços

Interpretações da teoria do valor trabalho encontram dificuldades em definir o papel e o lugar das atividades de serviço com relação à produção ou não de valor. Esse problema ganha magnitude na medida em que a perspectiva histórica mostra que os serviços são grandes empregadores de mão de obra na atualidade. Tradicionalmente, os serviços são entendidos como atividades não produtivas, devido ao fato, dentre outros argumentos, de que não resultam em materialização na forma de mercadorias, ou que não produzem novos valores e mais-valia. O objetivo deste artigo é examinar essa questão e sugerir a proposição de que certos serviços, que preenchem determinadas condições, podem ser interpretados como produtivos de valor e de mais-valia. O artigo examina as categorias materialidade e imaterialidade, assim como as de trabalho produtivo e não produtivo de valor, introduzindo, a seguir, critérios para distinguir trabalhos produtivos e não produtivos de valor no setor de serviços. Com isso, pretende contribuir para clarificar o entendimento da teoria do valor trabalho num terreno entrecruzado de polêmicas e de posições teóricas diferenciadas. _____________________________________________________________________________________________ ABSTRACT

Queueing Models with Vacations and Working Vacations

The thesis entitled “Queueing Models with Vacations and Working Vacations" consists of seven chapters including the introductory chapter. In chapters 2 to 7 we analyze different queueing models highlighting the role played by vacations and working vacations. The duration of vacation is exponentially distributed in all these models and multiple vacation policy is followed.In chapter 2 we discuss an M/M/2 queueing system with heterogeneous servers, one of which is always available while the other goes on vacation in the absence of customers waiting for service. Conditional stochastic decomposition of queue length is derived. An illustrative example is provided to study the effect of the input parameters on the system performance measures. Chapter 3 considers a similar setup as chapter 2. The model is analyzed in essentially the same way as in chapter 2 and a numerical example is provided to bring out the qualitative nature of the model. The MAP is a tractable class of point process which is in general nonrenewal. In spite of its versatility it is highly tractable as well. Phase type distributions are ideally suited for applying matrix analytic methods. In all the remaining chapters we assume the arrival process to be MAP and service process to be phase type. In chapter 4 we consider a MAP/PH/1 queue with working vacations. At a departure epoch, the server finding the system empty, takes a vacation. A customer arriving during a vacation will be served but at a lower rate.Chapter 5 discusses a MAP/PH/1 retrial queueing system with working vacations.In chapter 6 the setup of the model is similar to that of chapter 5. The signicant dierence in this model is that there is a nite buer for arrivals.Chapter 7 considers an MMAP(2)/PH/1 queueing model with a nite retrial group

Queueing Models with Vacations and Working Vacations

The objective of the study of \Queueing models with vacations and working vacations" was two fold; to minimize the server idle time and improve the e ciency of the service system. Keeping this in mind we considered queueing models in di erent set up in this thesis. Chapter 1 introduced the concepts and techniques used in the thesis and also provided a summary of the work done. In chapter 2 we considered an M=M=2 queueing model, where one of the two heterogeneous servers takes multiple vacations. We studied the performance of the system with the help of busy period analysis and computation of mean waiting time of a customer in the stationary regime. Conditional stochastic decomposition of queue length was derived. To improve the e ciency of this system we came up with a modi ed model in chapter 3. In this model the vacationing server attends the customers, during vacation at a slower service rate. Chapter 4 analyzed a working vacation queueing model in a more general set up. The introduction of N policy makes this MAP=PH=1 model di erent from all working vacation models available in the literature. A detailed analysis of performance of the model was provided with the help of computation of measures such as mean waiting time of a customer who gets service in normal mode and vacation mode.

Incorporating priorities for waiting customers in the hypercube queuing model with application to an emergency medical service system in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

POLLING SYSTEMS WITH PARAMETER REGENERATION, THE GENERAL CASE

We consider a polling model with multiple stations, each with Poisson arrivals and a queue of infinite capacity. The service regime is exhaustive and there is Jacksonian feedback of served customers. What is new here is that when the server comes to a station it chooses the service rate and the feedback parameters at random; these remain valid during the whole stay of the server at that station. We give criteria for recurrence, transience and existence of the sth moment of the return time to the empty state for this model. This paper generalizes the model, when only two stations accept arriving jobs, which was considered in [Ann. Appl. Probab. 17 (2007) 1447-1473]. Our results are stated in terms of Lyapunov exponents for random matrices. From the recurrence criteria it can be seen that the polling model with parameter regeneration can exhibit the unusual phenomenon of null recurrence over a thick region of parameter space.