3,038 research outputs found
Can virtual reality predict body part discomfort and performance of people in realistic world for assembling tasks?
This paper presents our work on relationship of evaluation results between
virtual environment (VE) and realistic environment (RE) for assembling tasks.
Evaluation results consist of subjective results (BPD and RPE) and objective
results (posture and physical performance). Same tasks were performed with same
experimental configurations and evaluation results were measured in RE and VE
respectively. Then these evaluation results were compared. Slight difference of
posture between VE and RE was found but not great difference of effect on
people according to conventional ergonomics posture assessment method.
Correlation of BPD and performance results between VE and RE are found by
linear regression method. Moreover, results of BPD, physical performance, and
RPE in VE are higher than that in RE with significant difference. Furthermore,
these results indicates that subjects feel more discomfort and fatigue in VE
than RE because of additional effort required in VE
A novel approach for determining fatigue resistances of different muscle groups in static cases
In ergonomics and biomechanics, muscle fatigue models based on maximum
endurance time (MET) models are often used to integrate fatigue effect into
ergonomic and biomechanical application. However, due to the empirical
principle of those MET models, the disadvantages of this method are: 1) the MET
models cannot reveal the muscle physiology background very well; 2) there is no
general formation for those MET models to predict MET. In this paper, a
theoretical MET model is extended from a simple muscle fatigue model with
consideration of the external load and maximum voluntary contraction in passive
static exertion cases. The universal availability of the extended MET model is
analyzed in comparison to 24 existing empirical MET models. Using mathematical
regression method, 21 of the 24 MET models have intraclass correlations over
0.9, which means the extended MET model could replace the existing MET models
in a general and computationally efficient way. In addition, an important
parameter, fatigability (or fatigue resistance) of different muscle groups,
could be calculated via the mathematical regression approach. Its mean value
and its standard deviation are useful for predicting MET values of a given
population during static operations. The possible reasons influencing the
fatigue resistance were classified and discussed, and it is still a very
challenging work to find out the quantitative relationship between the fatigue
resistance and the influencing factors
Numerical calculation of wing-bending moment with real-time strain monitoring by FBG modulation
This paper presents an application of Structural Health Monitoring System based on Fiber Bragg Grating sensors (FBGs) dedicated to wing-bending moment. A numerical calculation of bending moment is proposed to the application of real-time wing-bending moment monitoring. With the advantage of anti-electromagnetic interference, small size and light weight, Fiber Bragg grating (FBG) sensors have been applied in structural health monitoring system (SHMS). An experiment was performed in full-scale fatigue test of an aircraft, and the wings of aircraft were subjected to specific loading conditions, and the strain data was collected by FBGs’ demodulation. The relationship matrix K between the strain and the wing-bending moment was established. It is a new approach for the wing-bending moment real-time monitoring with the simple FBG strain collection modulation
On sumsets involving th power residues
In this paper, we study some topics concerning the additive decompostions of
the set of all th power residues modulo a prime . For example, we
prove that
where is the number of primes and denotes the
cardinality of the set
\{p\le x: p\equiv1\pmod k; D_k\ \text{has a non-trivial 2-additive
decomposition}\}.$
Correlation of Chimerism with Acute Graft-versus-Host Disease in Rats following Liver Transplantation
The accurate diagnosis of acute graft-versus-host disease following liver transplantation (LTx-aGVHD) has been hampered. Chimerism appears in the majority of recipients after LT and its significance in the diagnosis of LTx-aGVHD has not been clearly established. To demonstrate the significance of chimerism on the diagnosis of LTx-aGVHD, we compared the change of chimerism in syngeneic LT recipients, semiallogeneic LT recipients, and LTx-aGVHD induced recipients. Chimerism in PBMCs following sex-mismatched LT was identified by real-time PCR based on a rat Y-chromosome-specific primer. All recipients in semiallogeneic group grew in a normal pattern. However, when 4 × 108 donor splenocytes were transferred simultaneously during LT, the morbidity of lethal aGVHD was 100%. The chimerism appeared slightly higher in the semiallogeneic group than in the syngeneic LT group, but the difference was not significant. However, when the recipients developed lethal aGVHD after LT, chimerism in the PBMCs increased progressively, and even at an early time, a significant increase in chimerism was observed. In conclusion, high level chimerism correlated well with LTx-aGVHD, and detection of chimerism soon after transplantation may be of value in the diagnosis of LTx-aGVHD prior to the onset of symptoms
Single transverse-spin asymmetry for -meson production in semi-inclusive deep inelastic scattering
We study the single-transverse spin asymmetry for open charm production in
the semi-inclusive lepton-hadron deep inelastic scattering. We calculate the
asymmetry in terms of the QCD collinear factorization approach for mesons
at high enough , and find that the asymmetry is proportional to the
twist-three tri-gluon correlation function in the proton. With a simple model
for the tri-gluon correlation function, we estimate the asymmetry for both
COMPASS and eRHIC kinematics, and discuss the possibilities of extracting the
tri-gluon correlation function in these experiments.Comment: 13 pages, 7 figure
Correlative Preference Transfer with Hierarchical Hypergraph Network for Multi-Domain Recommendation
Advanced recommender systems usually involve multiple domains (scenarios or
categories) for various marketing strategies, and users interact with them to
satisfy their diverse demands. The goal of multi-domain recommendation is to
improve the recommendation performance of all domains simultaneously.
Conventional graph neural network based methods usually deal with each domain
separately, or train a shared model for serving all domains. The former fails
to leverage users' cross-domain behaviors, making the behavior sparseness issue
a great obstacle. The latter learns shared user representation with respect to
all domains, which neglects users' domain-specific preferences. These
shortcomings greatly limit their performance in multi-domain recommendation.
To tackle the limitations, an appropriate way is to learn from multi-domain
user feedbacks and obtain separate user representations to characterize their
domain-specific preferences. In this paper we propose , a
hierarchical hypergraph network based correlative preference transfer framework
for multi-domain recommendation. represents multi-domain
feedbacks into a unified graph to help preference transfer via taking full
advantage of users' multi-domain behaviors. We incorporate two hyperedge-based
modules, namely dynamic item transfer module (Hyper-I) and adaptive user
aggregation module (Hyper-U). Hyper-I extracts correlative information from
multi-domain user-item feedbacks for eliminating domain discrepancy of item
representations. Hyper-U aggregates users' scattered preferences in multiple
domains and further exploits the high-order (not only pair-wise) connections
among them to learn user representations. Experimental results on both public
datasets and large-scale production datasets verify the superiority of
for multi-domain recommendation.Comment: Work in progres
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