999 research outputs found
Turbo Packet Combining for Broadband Space-Time BICM Hybrid-ARQ Systems with Co-Channel Interference
In this paper, efficient turbo packet combining for single carrier (SC)
broadband multiple-input--multiple-output (MIMO) hybrid--automatic repeat
request (ARQ) transmission with unknown co-channel interference (CCI) is
studied. We propose a new frequency domain soft minimum mean square error
(MMSE)-based signal level combining technique where received signals and
channel frequency responses (CFR)s corresponding to all retransmissions are
used to decode the data packet. We provide a recursive implementation algorithm
for the introduced scheme, and show that both its computational complexity and
memory requirements are quite insensitive to the ARQ delay, i.e., maximum
number of ARQ rounds. Furthermore, we analyze the asymptotic performance, and
show that under a sum-rank condition on the CCI MIMO ARQ channel, the proposed
packet combining scheme is not interference-limited. Simulation results are
provided to demonstrate the gains offered by the proposed technique.Comment: 12 pages, 7 figures, and 2 table
Finalité de l’adhésion des organismes employeurs au dispositif DAIP via la nature des postes occupés et le type de difficultés rencontrées par les jeunes diplômés insérés
The position of employment in Algeria has been shaped by different factors, for instance; the unemployment of university graduates and other graduates from colleges and institutes. In fact, due to the generalization of the teaching- learning policy at university; there has been an emergence of a great number of heterogeneous graduates looking for employment. Actually, the economic context, in Algeria, is unable to face and enroll all applicants because some streams are not necessarily looked for by employers and recruiting companies. That’s why many university graduates suffer from redundancy, these include (historians, psychologists, sociologists…etc). It’s obvious that there is a gap between the training policy and the real needs of the economic sector in terms of skills and savoir-faire in general; this is why some companies complain about the lack of qualified staff. So as to satisfy their economic needs, the leaders of those companies don’t hesitate to get in touch with some employment service agencies such as ANEM (in charge of directing the DAIP system). This case study aims to answer and find out the purpose behind joining this employment device by those companies. Is it aimed at economic revival and succession? Or finding a new generation of workers, company leaders’ through transmitting knowledge and savoir-faire? Or is it simply to avoid extra charges related to adaptation of new workers? La situation de l’emploi en Algérie est caractérisée par plusieurs phénomènes entre autres, le chômage des universitaires et des diplômés en général. En effet, l’université, à la faveur de la démocratisation de l’enseignement, a mis sur le marché de l’emploi des milliers d’universitaires de formations hétéroclites. Il va de soi que l’économie algérienne en général ne peut absorber toutes les promotions d’universitaires, d’autant plus que certaines filières ne sont pas forcément recherchées par les entreprises et souffrent d’in employabilité (historiens, psychologues, sociologues…etc). Il est certain, qu’il y’a un décalage entre les formations assurées et les besoins réels de l’économie en termes de savoir, de savoir-faire et savoir être en général. Sur ce côté, les entreprises se plaignent d’un manque de personnel qualifié. Pour combler leur manque de personnel, les dirigeants des organismes employeurs n’hésitent pas à faire appel aux intermédiaires de l’emploi dont l’ANEM, l’agence chargée de la gestion du dispositif DAIP. Dans ce travail nous nous somme interroger : Est-ce-que l’objectif de leur adhésion est la recherche de garantir la succession de leur effectif par le transfert de connaissances entre générations ou c’est uniquement d’éviter des frais liés à l’adaptation
Revisiting monotop production at the LHC
Scenarios of new physics where a single top quark can be produced in
association with large missing energy (monotop) have been recently studied both
from the theoretical point of view and by experimental collaborations. We
revisit the originally proposed monotop setup by embedding the effective
couplings of the top quark in an SU(2)L invariant formalism. We show that
minimality selects one model for each of the possible production mechanisms: a
scalar field coupling to a right-handed top quark and an invisible fermion when
the monotop system is resonantly produced, and a vector field mediating the
interactions of a dark sector to right-handed quarks for the non-resonant
production mode. We study in detail constraints on the second class of
scenarios, originating from contributions to standard single top processes when
the mediator is lighter than the top quark and from the dark matter relic
abundance when the mediator is heavier than the top quark.Comment: 24 pages, 7 figures; version accepted by JHE
L’intégration linguistique et sociale des immigrants d’origine algérienne à Montréal
My thesis deals with the integration of Algerian immigrants in Montreal in relation to their linguistic practices and attitudes. More concretely, it intends to raise the following main issue: Algerian immigrants are francophones, and Quebec builds its integration policy on the French language; however, these immigrants seem to be the least integrated in the province. This leads one to ask an important question: is mastering the host country’s language a sufficient condition for the integration of immigrants?
I approach this issue under the angles of two disciplines which are Linguistic Anthropology and Immigration studies. Through a methodology based on a deep and continuous immersion, the aim of my study is to report on the mode and the degree of adaptation of Algerian immigrants to the Quebecois society. In this way, I plan to contribute in shedding light on the problematic of cultural diversity and coexistence of different communities. Moreover, my study is interesting because it deals with a theme that is not yet much researched as Algerian immigration to Quebec is quite recent.
My study shows that both the Quebec government and the Algerian immigrants are making efforts towards the integration of these migrants. Although the latter still face problems of unemployment, discrimination and cultural adaptation, their activities in different domains attest that they have come to Quebec with a will to stay. The success of their integration requires the overcoming of the prejudices that they and the host society have towards each other
Accurate Measurement of Dynamic on-State Resistances of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter
Because of trapped charges in GaN transistor structure, device dynamic ON-state resistance RDSon is increased when it is operated in high frequency switched power converters, in which device is possibly operated by zero voltage switching (ZVS) to reduce its turn-ON switching losses. When GaN transistor finishes ZVS during one switching period, device has been operated under both reverse and forward conduction. Therefore its dynamic RDSon under both conduction modes needs to be carefully measured to understand device power losses. For this reason, a measurement circuit with simple structure and fast dynamic response is proposed to characterise device reverse and forward RDSon. In order to improve measurement sensitivity when device switches at high frequency, a trapezoidal current mode is proposed to measure device RDSon under almost constant current, which resolves measurement sensitivity issues caused by unavoidable measurement circuit parasitic inductance and measurement probes deskew in conventional device characterisation method by triangle current mode. Proposed measurement circuit and measurement method is then validated by first characterising a SiC-MOSFET with constant RDSon. Then, the comparison on GaN-HEMT dynamic RDSon measurement results demonstrates the improved accuracy of proposed trapezoidal current mode over conventional triangle current mode when device switches at 1MHz
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