1,360 research outputs found
Multi-Agent Deep Reinforcement Learning for Efficient Passenger Delivery in Urban Air Mobility
It has been considered that urban air mobility (UAM), also known as
drone-taxi or electrical vertical takeoff and landing (eVTOL), will play a key
role in future transportation. By putting UAM into practical future
transportation, several benefits can be realized, i.e., (i) the total travel
time of passengers can be reduced compared to traditional transportation and
(ii) there is no environmental pollution and no special labor costs to operate
the system because electric batteries will be used in UAM system. However,
there are various dynamic and uncertain factors in the flight environment,
i.e., passenger sudden service requests, battery discharge, and collision among
UAMs. Therefore, this paper proposes a novel cooperative MADRL algorithm based
on centralized training and distributed execution (CTDE) concepts for reliable
and efficient passenger delivery in UAM networks. According to the performance
evaluation results, we confirm that the proposed algorithm outperforms other
existing algorithms in terms of the number of serviced passengers increase
(30%) and the waiting time per serviced passenger decrease (26%).Comment: 6 pages, 5 figure
Linking Authentic Leadership With Employee Initiative Behavior and Task Performance: The Mediating Role of Emotional Sharing and Communication Satisfaction
Our study aims to explore the process through which authentic leadership leads to employees’ initiative behavior and task performance. In particular, we focused on the mediating roles of emotional sharing and communication satisfaction. Based on data collected from 242 employee-supervisor dyads, we found that authentic leadership was significantly related to emotional sharing, which was sequentially significantly related to communication satisfaction. Communication satisfaction was significantly associated with initiative behavior and task performance. In addition, emotional sharing and communication satisfaction played significant mediating roles not only in the relationship between authentic leadership and initiative behavior, but also in the relationship between authentic leadership and task performance. The limitations and implications for future research and practice are discussed
Critical importance of the correction of contrast transfer function for transmission electron microscopy-mediated structural biology
Satellite Clustering for Non-Terrestrial Networks: Concept, Architectures, and Applications
Recently, mega-constellations with a massive number of low Earth orbit (LEO)
satellites are being considered as a possible solution for providing global
coverage due to relatively low latency and high throughput compared to
geosynchronous orbit satellites. However, as the number of satellites and
operators participating in the LEO constellation increases, inter-satellite
interference will become more severe, which may yield marginal improvement or
even decrement in network throughput. In this article, we introduce the concept
of satellite clusters that can enhance network performance through satellites'
cooperative transmissions. The characteristics, formation types, and
transmission schemes for the satellite clusters are highlighted. Simulation
results evaluate the impact of clustering from coverage and capacity
perspectives, showing that when the number of satellites is large, the
performance of clustered networks outperforms the unclustered ones. The viable
network architectures of the satellite cluster are proposed based on the 3GPP
standard. Finally, the future applications of clustered satellite networks are
discussed.Comment: 7 pages, 7 figures, 1 table, submitted to IEEE Vehicular Technology
Magazin
A Novel Pinkish-White Flower Color Variant Is Caused by a New Allele of Flower Color Gene W1 in Wild Soybean (Glycine soja)
The enzyme flavonoid 3',5'-hydroxylase (F3'5'H) plays an important role in producing anthocyanin pigments in soybean. Loss of function of the W1 locus encoding F3'5'H always produces white flowers. However, few color variations have been reported in wild soybean. In the present study, we isolated a new color variant of wild soybean accession (IT261811) with pinkish-white flowers. We found that the flower's pinkish-white color is caused by w1-s3, a single recessive allele of W1. The SNP detected in the mutant caused amino acid substitution (A(304)S) in a highly conserved SRS4 domain of F3'5'H proteins. On the basis of the results of the protein variation effect analyzer (PROVEAN) tool, we suggest that this mutation may lead to hypofunctional F3'5'H activity rather than non-functional activity, which thereby results in its pinkish-white color
Design of the VISTA-ITL Test Facility for an Integral Type Reactor of SMART and a Post-Test Simulation of a SBLOCA Test
To validate the performance and safety of an integral type reactor of SMART, a thermal-hydraulic integral effect test facility, VISTA-ITL, is introduced with a discussion of its scientific design characteristics. The VISTA-ITL was used extensively to assess the safety and performance of the SMART design, especially for its passive safety system such as a passive residual heat removal system, and to validate various thermal-hydraulic analysis codes. The VISTA-ITL program includes several tests on the SBLOCA, CLOF, and PRHRS performances to support a verification of the SMART design and contribute to the SMART design licensing by providing proper test data for validating the system analysis codes. A typical scenario of SBLOCA was analyzed using the MARS-KS code to assess the thermal-hydraulic similarity between the SMART design and the VISTA-ITL facility, and a posttest simulation on a SBLOCA test for the shutdown cooling system line break has been performed with the MARS-KS code to assess its simulation capability for the SBLOCA scenario of the SMART design. The SBLOCA scenario in the SMART design was well reproduced using the VISTA-ITL facility, and the measured thermal-hydraulic data were properly simulated with the MARS-KS code
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