6,441 research outputs found
Performance Analysis of a Dual-Hop Cooperative Relay Network with Co-Channel Interference
This paper analyzes the performance of a dual-hop amplify-and-forward (AF) cooperative relay network in the presence of direct link between the source and destination and multiple co-channel interferences (CCIs) at the relay. Specifically, we derive the new analytical expressions for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR) and the average symbol error rate (ASER) of the relay network. Computer simulations are given to confirm the validity of the analytical results and show the effects of direct link and interference on the considered AF relay network
Real-time Data Flow Control for CBM-TOF Super Module Quality Evaluation
Super module assembled with MRPC detectors is the component unit of TOF (Time
of Flight) system for the Compressed Baryonic Matter (CBM) experiment. Quality
of super modules needs to be evaluated before it is applied in CBM-TOF. Time
signals exported from super module are digitalized at TDC (Time to Digital
Converter) station. Data rate is up to 6 Gbps at each TDC station, which brings
a tremendous pressure for data transmission in real time. In this paper, a
real-time data flow control method is designed. In this control method, data
flow is divided into 3 types: scientific data flow, status data flow and
control data flow. In scientific data flow, data of each TDC station is divided
into 4 sub-flows, and then is read out by a parallel and hierarchical network,
which consists of multiple readout mother boards and daughter boards groups. In
status data flow, status data is aggregated into a specific readout mother
board. Then it is uploaded to DAQ via readout daughter board. In control data
flow, control data is downloaded to all circuit modules in the opposite
direction of status data flow. Preliminary test result indicated data of STS
was correctly transmitted to DAQ with no error and three type data flows were
control orderly in real time. This data flow control method can meet the
quality evaluation requirement of supper module in CBM-TOF
Spectrum of low-lying configurations with negative parity
Spectrum of low-lying five-quark configurations with strangeness quantum
number and negative parity is studied in three kinds of constituent
quark models, namely the one gluon exchange, Goldstone Boson exchange, and
instanton-induced hyperfine interaction models, respectively. Our numerical
results show that the lowest energy states in all the three employed models are
lying at 1800 MeV, about 200 MeV lower than predictions of various
quenched three-quark models. In addition, it is very interesting that the state
with the lowest energy in one gluon exchange model is with spin 3/2, but 1/2 in
the other two models.Comment: Version published in Phys. Rev.
Quantum metrology in the noisy intermediate-scale quantum era
Quantum metrology pursues the physical realization of higher-precision
measurements to physical quantities than the classically achievable limit by
exploiting quantum features, such as entanglement and squeezing, as resources.
It has potential applications in developing next-generation frequency
standards, magnetometers, radar, and navigation. However, the ubiquitous
decoherence in the quantum world degrades the quantum resources and forces the
precision back to or even worse than the classical limit, which is called the
no-go theorem of noisy quantum metrology and greatly hinders its applications.
Therefore, how to realize the promised performance of quantum metrology in
realistic noisy situations attracts much attention in recent years. We will
review the principle, categories, and applications of quantum metrology.
Special attention will be paid to different quantum resources that can bring
quantum superiority in enhancing sensitivity. Then, we will introduce the no-go
theorem of noisy quantum metrology and its active control under different kinds
of noise-induced decoherence situations.Comment: Minireview of quantum metrology based on Lectures given at the summer
school "Fundamental and Frontiers of Quantum Metrology and Quantum
Computation" held in Bohai University, China, from 23 July to 8 Augus
Population Genetics of Two Asexually and Sexually Reproducing Psocids Species Inferred by the Analysis of Mitochondrial and Nuclear DNA Sequences
Background: The psocids Liposcelis bostrychophila and L. entomophila (Psocoptera: Liposcelididae) are found throughout the world and are often associated with humans, food stores and habitations. These insects have developed high levels of resistance to various insecticides in grain storage systems. However, the population genetic structure and gene flow of psocids has not been well categorized, which is helpful to plan appropriate strategies for the control of these pests. Methodology/Principal Findings: The two species were sampled from 15 localities in China and analyzed for polymorphisms at the mitochondrial DNA (Cytb) and ITS (ITS1-5.8S-ITS2) regions. In total, 177 individual L. bostrychophila and 272 individual L. entomophila were analysed. Both Cytb and ITS sequences showed high genetic diversity for the two species with haplotype diversities ranged from 0.15460.126 to 1.00060.045, and significant population differentiation (mean FST = 0.358 for L. bostrychophila; mean FST = 0.336 for L. entomophila) was also detected among populations investigated. A Mantel test indicated that for both species there was no evidence for isolation-by-distance (IBD). The neutrality test and mismatch distribution statistics revealed that the two species might have undergone population expansions in the past. Conclusion: Both L. bostrychophila and L. entomophila displayed high genetic diversity and widespread population genetic differentiation within and between populations. The significant population differentiation detected for both psocids may b
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