3,254 research outputs found
Ring-theoretic properties of PVMDs
We extend to Pr\"ufer -multiplication domains some distinguished
ring-theoretic properties of Pr\"ufer domains. In particular we consider the
t##-property, the -radical trace property, -divisoriality and
-stability.Comment: 15 pages, to appear in Communications in Algebr
w-Divisorial Domains
We study the class of domains in which each w-ideal is divisorial, extending
several properties of divisorial and totally divisorial domains to a much wider
class of domains. In particular we consider PvMDs and Mori domains
On the Convergence Speed of Turbo Demodulation with Turbo Decoding
Iterative processing is widely adopted nowadays in modern wireless receivers
for advanced channel codes like turbo and LDPC codes. Extension of this
principle with an additional iterative feedback loop to the demapping function
has proven to provide substantial error performance gain. However, the adoption
of iterative demodulation with turbo decoding is constrained by the additional
implied implementation complexity, heavily impacting latency and power
consumption. In this paper, we analyze the convergence speed of these combined
two iterative processes in order to determine the exact required number of
iterations at each level. Extrinsic information transfer (EXIT) charts are used
for a thorough analysis at different modulation orders and code rates. An
original iteration scheduling is proposed reducing two demapping iterations
with reasonable performance loss of less than 0.15 dB. Analyzing and
normalizing the computational and memory access complexity, which directly
impact latency and power consumption, demonstrates the considerable gains of
the proposed scheduling and the promising contributions of the proposed
analysis.Comment: Submitted to IEEE Transactions on Signal Processing on April 27, 201
Semistar Dedekind Domains
Let be an integral domain and a semistar operation on . As a
generalization of the notion of Noetherian domains to the semistar setting, we
say that is a --Noetherian domain if it has the ascending chain
condition on the set of its quasi----ideals. On the other hand, as an
extension the notion of Pr\"ufer domain (and of Pr\"{u}fer --multiplication
domain), we say that is a Pr\"ufer --multiplication domain
(PMD, for short) if is a valuation domain, for each
quasi----maximal ideal of . Finally, recalling that a
Dedekind domain is a Noetherian Pr\"{u}fer domain, we define a
--Dedekind domain to be an integral domain which is --Noetherian
and a PMD. In the present paper, after a preliminary study of
--Noetherian domains, we investigate the --Dedekind domains. We
extend to the --Dedekind domains the main classical results and several
characterizations proven for Dedekind domains. In particular, we obtain a
characterization of a --Dedekind domain by a property of decomposition
of any semistar ideal into a ``semistar product'' of prime ideals. Moreover, we
show that an integral domain is a --Dedekind domain if and only if
the Nagata semistar domain Na is a Dedekind domain. Several
applications of the general results are given for special cases of the semistar
operation
First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii.
Fungal infections in the central nervous system (CNS) are associated with significant morbidity and death. Transient fungemia in immunocompetent patients without any other risk factors for fungemia has been suggested as a possible mechanism that may lead to serious fungal ventriculoperitoneal (VP) shunt infections, but evidence is lacking. The clinical spectrum, diagnosis, and optimal therapy of Cyberlindnera fabianii infections remain to be determined. We describe the first case of CNS infection due to C. fabianii that occurred in an immunocompetent adult with a VP shunt. Spontaneous translocation with yeast that is not part of the normal gastrointestinal flora in the setting of ingestion of multiple servings of a fermentation product was the likely source from which Cyberlindnera fabianii gained entrance into the VP shunt system, causing meningitis in this patient. The authors conclude that, in view of the high morbidity associated with yeast infection of the CNS, long-term antifungal therapy should be strongly considered in cases where the VP shunt cannot be completely removed. Transient fungemia may lead to invasive disease in an immunocompetent host with VP shunt, even in the absence of any other risk factors for fungemia and even after remote placement of the VP shunt
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Adiabatic DC-AC Power Converter with 99% Efficiency
This paper describes a novel approach to building a high efficiency and dimensionally compact power converter / inverter. A prototype was built for the Google / IEEE Little Box competition. The converter takes a 400-450 V DC input and creates a single-phase 230V AC output. It is capable of supplying 2kW continuously to a load. The design is based on a multi-winding DC-DC active transformer operating at around 500 kHz. The AC output sinewave is synthesized by switching between the DC tap levels produced by the active transformer. The transformer MOSFETs operate under ZVS and have an adiabatic gate driver. Early tests on the prototype demonstrate a high fidelity sinewave output and very high efficiency (better than 99%)
Ehteshami, Anoushiravan. Iran: Stuck in Transition. London and New York: Routledge, 2017.
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