A Generational Divide? Coping With Ethnic Prejudice and Inequality Among Romanian Roma Transnational Returnees

Roma people are likely Europe’s most discriminated and marginalized minority. In the past years, increasing attention has been paid to their migration to Western Europe and their limited social mobility in their countries of destination. Our article focuses on the "post‐return" experiences of Roma and the changes generated by return migration in their communities of origin, a topic largely neglected so far. We build on recent debates around post‐return positionality, asking how adult and old Roma returnees experience return. We thus contribute to the growing literature on return migration and lifecourse that distinguishes between the return migration of children and youth, that of adults, and that of older migrants. Focusing on Roma returnees, we employ an understanding of migration not just as a means of generating resources, but also as a learning process where the Roma population acquires new ideas and a sense of agency and dignity. Informed by long‐term fieldwork in ethnically mixed localities in Romania (including participant observation and 76 semi‐structured interviews), we inquire into the ethnic relations and negotiations between Roma and non‐Roma populations. Migration results in a weakening of the economic dependency of the Roma on the non‐Roma. In this new context, which is still marred by ethnic prejudice and inequality, we analysed how local interethnic relations were reshaped by the returned Roma’s new consumption practices, new modes of communication, and new claims for equality. While adult Roma tend to demand equality and decent treatment, setting in motion a process of ethnic change, older returned Roma tend to maintain more submissive practices

FMCW Transceiver Wideband Sweep Nonlinearity Software Correction

International audienceThis paper presents a novel sideband sweep nonlinearity software correction method for a frequency modulated continuous wave (FMCW) transceiver based on the high-order ambiguity function (HAF) and time resampling. By emphasizing the polynomial-phase nature of the FMCW signal, it is shown that the HAF processing algorithm is well suited for estimating the sweep nonlinearity coefficients. The estimated coefficients are used to build a correction function which is applied by resampling the beat signal on each sweep interval. The sweep nonlinearity correction procedure is validated on real data acquired with a low-cost X-band T/R module

Short-Range FMCW Radar Platform for Millimetric Displacements Measurement

International audienceA frequency modulated continuous wave (FMCW) radar platform for millimetric displacement measurements of short-range targets is presented in this paper. The platform's transceiver is based on a heterodyne architecture because the beat frequency is relatively small for short-range targets and it can be placed in the frequency range influenced by the specific homodyne architecture problems: DC offset, self-mixing and 1/f noise. The platform's displacement measurement capability was tested on range profiles and SAR images acquired for various targets. The displacements were computed from the interferometric phase. The displacements errors were situated below 0.1 mm for metallic bar targets placed at a few meters from the radar

Nonlinearity Correction Algorithm for Wideband FMCW Radars

International audienceThis paper presents a novel nonlinearity correction algorithm for wideband frequency modulated continuous wave (FMCW) radars based on high-order ambiguity functions (HAF) and time resampling. By emphasizing the polynomial phase nature of the FMCW signal, it is shown that the HAF is an excellent tool for estimating the sweep nonlinearity polynomial coefficients. The estimated coefficients are used to build a correction function which is applied to the beat signal by time resampling . The nonlinearity correction algorithm is tested by simulation and validated on real data sets acquired with an X-band FMCW radar

Short-range wideband FMCW radar for millimetric displacement measurements

International audienceThe frequency modulated continuous wave (FMCW) radar is an alternative to the pulse radar when the distance to the target is short. Typical FMCW radar implementations have a homodyne architecture transceiver which limits the performances for short-range applications: the beat frequency can be relatively small and placed in the frequency range affected by the specific homodyne issues (DC offset, self-mixing and 1/f noise). Additionally, one classical problem of a FMCW radar is that the voltage controlled oscillator adds a certain degree of nonlinearity which can cause a dramatic resolution degradation for wideband sweeps. This paper proposes a short-range X-band FMCW radar platform which solves these two problems by using a heterodyne transceiver and a wideband nonlinearity correction algorithm based on high-order ambiguity functions and time resampling. The platform's displacement measurement capability was tested on range profiles and synthetic aperture radar (SAR) images acquired for various targets. The displacements were computed from the interferometric phase and the measurement errors were situated below 0.1 mm for metal bar targets placed at a few meters from the radar

SAR Images Refocusing and Scattering Center Detection for Infrastructure Monitoring

International audienceInfrastructure monitoring applications can require the tracking of slowly moving points of a certain structure. Given a certain point from a structure to be monitored, in the context of available SAR products where the image is already focused in a slant range - azimuth grid, it is not obvious if this point is the scattering center, if it is in layover or if it is visible from the respective orbit. This paper proposes a refocusing procedure of SAR images on a set of measured points among with a 4D tomography based scattering center detection. The refocusing procedure consists of an azimuth de-focusing followed by a modified back-projection on the given set of points. The presence of a scattering center at the given positions is detected by computing the local elevation-velocity plane for each point and testing if the main response is at zero elevation. The refocusing and scattering center detection algorithm is validated on real data acquired with the TerraSAR-X satellite during March-June 2012. The mean displacement velocities of the detected scatterers show good agreement with the in-situ measurements

Deconvolution Method for Eliminating Reference Signal Coupling/Reflections in Bistatic SAR

Bistatic radar receivers that use an opportunistic transmitter require a reference channel to capture the original transmitted signal, which is then used as a reference signal for constructing the matched-filter during the range compression step. Because the reference signal is received from line-of-sight, it is orders in magnitude larger than the reflections captured by the receive channel. It is generally difficult to construct the system such that the reference signal is not leaked into the received signal, either via coupling in the circuitry or via reflections off objects in the vicinity of the receiver. Due to its much larger amplitude, the reference signal can easily mask smaller targets with its side-lobes. In this paper we propose a novel deconvolution method for bistatic SAR images as a means of eliminating leakage of the reference signal

International migration, return migration, and their effects. A comprehensive review on the Romanian case

Romanian migration is today one of the biggest, complex, and dynamic migration to Western Europe. This paper is a comprehensive review of the existing literature that aims at providing a full picture of this dynamic migratory process and discusses its far-reaching consequences. It first presents and characterizes the Romanian migration through the different phases during and after state socialism. The second part of the paper is dedicated to unfolding the socio-economic effects of the Romanian migration addressing the remitting behavior and its development over the past years. The issue of return migration is also addressed stressing that return is not much developed, however it has significant impacts through the emergence of returnees’ entrepreneurship. Finally we address some of the consequences of the medical doctors’ migration which is today considered one of the main migration challenges the country is facing