253 research outputs found
A dynamic truck dispatching problem in marine container terminal
In this paper, a dynamic truck dispatching problem of a marine container terminal is described and discussed. In this problem, a few containers, encoded as work instructions, need to be transferred between yard blocks and vessels by a fleet of trucks. Both the yard blocks and the quay are equipped with cranes to support loading/unloading operations. In order to service more vessels, any unnecessary idle time between quay crane (QC) operations need to be minimised to speed up the container transfer process. Due to the unpredictable port situations that can affect routing plans and the short calculation time allowed to generate one, static solution methods are not suitable for this problem. In this paper, we introduce a new mathematical model that minimises both the QC makespan and the truck travelling time. Three dynamic heuristics are proposed and a genetic algorithm hyperheuristic (GAHH) under development is also described. Experiment results show promising capabilities the GAHH may offer
Effect of Nitric Oxide Treatment on Storage Quality of Glorious Oranges
AbstractEffect of nitric oxide (NO) treatment on storage quality and disease resistance of Glorious oranges was investigated in the experiment. The results showed that NO treatment could effectively reduce disease incidence inoculated with Collletotichum goeosporioides Penz and inhibit the increase of lesion diameter of Glorious oranges during storage. Compared with the control, NO treatment kept higher level of titritable acidity (TA), soluble protein, ascorbic acid (ASA) and reducing sugar, and lower level of weight lose rate and soluble solid concentration (SSC), retarding ripening of fruits
A Platoon Regulation Algorithm to Improve the Traffic Performance of Highway Work Zones
This paper presents a cooperative traffic control strategy to increase the capacity of non-recurrent bottlenecks such as work zones by making full use of the spatial resources upstream of work zones. The upstream area is divided into two zones: the regulation area and the merging area. The basic logic is that a large gap is more efficient in accommodating merging vehicles than several small and scattered gaps with the same total length. In the regulation area, a non-linear programming model is developed to balance both traffic capacity improvements and safety risks. A two-step solving algorithm is proposed for finding optimal solutions. In the merging area, the sorting algorithm is used to design lane changing trajectories based on the regulated platoons. A case study is conducted, and the results indicate that the proposed model is able to significantly improve work zone capacity with minor disturbances to the traffic
Characteristics of carbon sources and sinks and their relationships with climate factors during the desertification reversal process in Yulin, China
Research on carbon sources/sinks in desert ecosystems is of great importance to understand the carbon cycle and its response to climate change. Net primary productivity (NPP) and net ecosystem productivity (NEP) are the two most important indictors for quantitatively evaluating carbon storage and can be used to indicate the response of terrestrial ecosystems to climate change. In this study, we used remote sensing data, meteorological data and vegetation type data to estimate the NPP and NEP using CASA model and soil respiration model from 2000 to 2020 in the region of Yulin, which is a typical desertification reversal region in the Mu Us Sandy Land. The spatial and temporal features of the NPP and NEP and their relationships with temperature and precipitation were determined. The results showed that both the annual NPP and NEP showed an increasing trend from 2000 to 2020 in the region of Yulin, where the terrestrial ecosystem acted as a carbon source until 2001 but turned into a sink thereafter. The carbon storage showed an increasing trend with a rate of 0.50 Tg C·a−1 from 2000 to 2020. Both the mean annual NPP and the total NEP increased from the west to the east of the region in spatial distribution. The total NEP indicated that the area with a carbon sink accounted for 89.22% of the total area, showing a carbon accumulation of 103.0 Tg C, and the carbon source area accounted for 10.78% of the total area with a carbon emission of 4.40 Tg C. The net carbon sequestration was 99.44 Tg C in the region of Yulin during the period from 2000 to 2020. Temperature had no significant effects on NPP and NEP for most areas of the region, while precipitation had a positive effect on the increasing NPP in 75.3% of areas and NEP in 30.07% of areas of the region. These results indicated that it is of utmost significance to protect terrestrial ecosystems from degradation, and ecological restoration projects are essential in combating desertification, which would be helpful for soil water conservation and could effectively increase carbon storage in desert ecosystems
Optimal Bus-Bridging Service under a Metro Station Disruption
A station disruption is an abnormal operational situation that the entrance or exit gates of a metro station have to be closed for a certain of time due to an unexpected incident. The passengers’ travel behavioral responses to the alternative station disruption scenarios and the corresponding controlling strategies are complex and hard to capture. This can lead to the hardness of estimating the changes of the network-wide passenger demand, which is the basis of carrying out a response plan. This paper will establish a model to solve the metro station disruption problem by providing optimal additional bus-bridging services. Two main contributions are made: "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""1"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" a three-layer discrete choice behavior model is developed to analyze the dynamic passenger flow demand under station disruption; and "mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"""mml:mo stretchy="false""("/mml:mo""mml:mn fontstyle="italic""2"/mml:mn""mml:mo stretchy="false"")"/mml:mo""/mml:math" an integrated algorithm is designed to manage and control the station disruption crisis by providing additional bus-bridging services with the objective of minimizing the total travel time of affected passengers and the operating cost of bridging-buses. Besides, the multimodal transport modes, including metro, bridging-bus, shared-bike, and taxi, are considered as passengers’ alternative choices in face of the station disruption. A numerical study based on the Beijing metro network shows that additional bus-bridging services can significantly eliminate the negative impact of the station disruption.
Document type: Articl
CloudBrain-MRS: An Intelligent Cloud Computing Platform for in vivo Magnetic Resonance Spectroscopy Preprocessing, Quantification, and Analysis
Magnetic resonance spectroscopy (MRS) is an important clinical imaging method
for diagnosis of diseases. MRS spectrum is used to observe the signal intensity
of metabolites or further infer their concentrations. Although the magnetic
resonance vendors commonly provide basic functions of spectra plots and
metabolite quantification, the widespread clinical research of MRS is still
limited due to the lack of easy-to-use processing software or platform. To
address this issue, we have developed CloudBrain-MRS, a cloud-based online
platform that provides powerful hardware and advanced algorithms. The platform
can be accessed simply through a web browser, without the need of any program
installation on the user side. CloudBrain-MRS also integrates the classic
LCModel and advanced artificial intelligence algorithms and supports batch
preprocessing, quantification, and analysis of MRS data from different vendors.
Additionally, the platform offers useful functions: 1) Automatically
statistical analysis to find biomarkers for diseases; 2) Consistency
verification between the classic and artificial intelligence quantification
algorithms; 3) Colorful three-dimensional visualization for easy observation of
individual metabolite spectrum. Last, both healthy and mild cognitive
impairment patient data are used to demonstrate the functions of the platform.
To the best of our knowledge, this is the first cloud computing platform for in
vivo MRS with artificial intelligence processing. We have shared our cloud
platform at MRSHub, providing free access and service for two years. Please
visit https://mrshub.org/software_all/#CloudBrain-MRS or
https://csrc.xmu.edu.cn/CloudBrain.html.Comment: 11 pages, 12 figure
One for Multiple: Physics-informed Synthetic Data Boosts Generalizable Deep Learning for Fast MRI Reconstruction
Magnetic resonance imaging (MRI) is a principal radiological modality that
provides radiation-free, abundant, and diverse information about the whole
human body for medical diagnosis, but suffers from prolonged scan time. The
scan time can be significantly reduced through k-space undersampling but the
introduced artifacts need to be removed in image reconstruction. Although deep
learning (DL) has emerged as a powerful tool for image reconstruction in fast
MRI, its potential in multiple imaging scenarios remains largely untapped. This
is because not only collecting large-scale and diverse realistic training data
is generally costly and privacy-restricted, but also existing DL methods are
hard to handle the practically inevitable mismatch between training and target
data. Here, we present a Physics-Informed Synthetic data learning framework for
Fast MRI, called PISF, which is the first to enable generalizable DL for
multi-scenario MRI reconstruction using solely one trained model. For a 2D
image, the reconstruction is separated into many 1D basic problems and starts
with the 1D data synthesis, to facilitate generalization. We demonstrate that
training DL models on synthetic data, integrated with enhanced learning
techniques, can achieve comparable or even better in vivo MRI reconstruction
compared to models trained on a matched realistic dataset, reducing the demand
for real-world MRI data by up to 96%. Moreover, our PISF shows impressive
generalizability in multi-vendor multi-center imaging. Its excellent
adaptability to patients has been verified through 10 experienced doctors'
evaluations. PISF provides a feasible and cost-effective way to markedly boost
the widespread usage of DL in various fast MRI applications, while freeing from
the intractable ethical and practical considerations of in vivo human data
acquisitions.Comment: 22 pages, 9 figures, 1 tabl
Reduced expression of N-Myc downstream-regulated gene 2 in human thyroid cancer
<p>Abstract</p> <p>Background</p> <p><it>NDRG</it>2 (N-Myc downstream-regulated gene 2) was initially cloned in our laboratory. Previous results have shown that <it>NDRG</it>2 expressed differentially in normal and cancer tissues. Specifically, <it>NDRG</it>2 mRNA was down-regulated or undetectable in several human cancers, and over-expression of <it>NDRG</it>2 inhibited the proliferation of cancer cells. <it>NDRG</it>2 also exerts important functions in cell differentiation and tumor suppression. However, it remains unclear whether <it>NDRG</it>2 participates in carcinogenesis of the thyroid.</p> <p>Methods</p> <p>In this study, we investigated the expression profile of human <it>NDRG</it>2 in thyroid adenomas and carcinomas, by examining tissues from individuals with thyroid adenomas (n = 40) and carcinomas (n = 35), along with corresponding normal tissues. Immunohistochemistry, quantitative RT-PCR and western blot methods were utilized to determine both the protein and mRNA expression status of Ndrg2 and c-Myc.</p> <p>Results</p> <p>The immunostaining analysis revealed a decrease of Ndrg2 expression in thyroid carcinomas. When comparing adenomas or carcinomas with adjacent normal tissue from the same individual, the mRNA expression level of <it>NDRG</it>2 was significantly decreased in thyroid carcinoma tissues, while there was little difference in adenoma tissues. This differential expression was confirmed at the protein level by western blotting. However, there were no significant correlations of <it>NDRG</it>2 expression with gender, age, different histotypes of thyroid cancers or distant metastases.</p> <p>Conclusion</p> <p>Our data indicates that <it>NDRG</it>2 may participate in thyroid carcinogenesis. This finding provides novel insight into the important role of <it>NDRG2 </it>in the development of thyroid carcinomas. Future studies are needed to address whether the down-regulation of <it>NDRG</it>2 is a cause or a consequence of the progression from a normal thyroid to a carcinoma.</p
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