265 research outputs found
A system dynamics model for urban taxi price simulation
Urban taxi services have been developing year on year, playing an increasingly important role in the economy and the transportation markets of each city. This increases interest in measuring their performance. This paper analysed the relationship among the four stakeholders (including administrative department, operational companies, taxi drivers and customers) for urban taxi passenger transport system in China, and applied System Dynamics (SD) model to explore the dynamic characteristics of urban taxi price system. The main achievements of this paper are as follows, firstly, this paper adopted stakeholder mapping to describe the relationships among the four stakeholders. Then analysed the causal flow diagrams and the different variables of urban taxi passenger transport system operation, and presented the SD model, which considers factors that affect the taxi operation. With the combination of taxi operation data of Harbin city, we simulated eleven urban taxi operation scenarios and proposed kinds of suggestions to improve urban taxi passenger transport system operation, which can provide a good basis for recommending policy decisions for urban taxi market
Application of Fast Deviation Correction Algorithm Based on Shape Matching Algorithm in Component Placement
For contradiction PC template matching between accuracy and speed, combined with the advantages of FPGA high speed parallel computing. This paper presents a FPGA-based rapid correction shape matching algorithm. Mainly in the FPGA, using shape matching and least squares method to calculate the angular deviation chip components. Use single instruction stream algorithm acceleration. Experimental results show that compared with traditional PC template matching algorithms, this algorithm to further improve the correction accuracy and greatly reducing correction time. And SMT machine vision correction can be obtained in a stable and efficient use
Special MMP for log canonical generalised pairs
We show that minimal models of -factorial NQC log canonical
generalised pairs exist, assuming the existence of minimal models of smooth
varieties. More generally, we prove that on a -factorial NQC log
canonical generalised pair we can run an MMP with scaling of an
ample divisor which terminates, assuming that it admits an NQC weak Zariski
decomposition or that is not pseudoeffective. As a consequence, we
establish several existence results for minimal models and Mori fibre spaces.Comment: v4: Theorem 1.2 is new, proved in the appendix written jointly with
Xiaowei Jiang; several other proofs slightly improve
A cumulative prospect theory approach to car owner mode choice behaviour prediction
The uncertain transportation environment makes travel’s mode choice decision-making behaviour become a complex and alterable process. Based on the cumulative prospect theory, this paper analysed the long-standing use of utility theory for the travel’s mode choice behaviour research. Car owner’s generalized cost includes the transport fare, travel time cost and penalty cost (early or delay); cumulative prospect theory was applied to describe the uncertain and risky prospect of car owner under congestion pricing policy. Through analysing two kinds of car owner’s generalized subjective perception costs on the four different transportation modes, including bus, subway, taxi and private car; we calculated the mode choice’s prospect value before and after the implementation of congestion pricing, and compared the difference of numerical example between cumulative prospect theory and expected utility theory. The results indicated that after the implementation of congestion pricing policy, the middle-level income car owner would prefer to choose taxi. Based on a state preference survey on travel’s mode choice behaviour, the survey results further validated our analysis. This paper for the first time adopted cumulative prospect theory to analyse travel’s mode choice behaviour after the implementation of congestion pricing policy, which can better explain car owner’s mode choice decisionmaking process under uncertain and risk condition. This study also can be helpful to many cities that wish to establish and implement the congestion pricing policy in practice
Insulin resistance predicts progression of de novo atherosclerotic plaques in patients with coronary heart disease: a one-year follow-up study
BACKGROUND: The aim of our study was to explore and evaluate the relationship between insulin resistance and progression of coronary atherosclerotic plaques. With the great burden coronary heart disease is imposing on individuals, healthcare professionals have already embarked on determining its potential modifiable risk factors in the light of preventive medicine. Insulin resistance has been generally recognized as a novel risk factor based on epidemiological studies; however, few researches have focused on its effect on coronary atherosclerotic plaque progression. METHODS: From June 7, 2007 to December 30, 2011, 366 patients received their index coronary angiogram and were subsequently found to have coronary atherosclerotic plaques or normal angiograms were consecutively enrolled in the study by the department of cardiology at the Ruijin Hospital, which is affiliated to the Shanghai Jiaotong University School of Medicine. All patients had follow-up angiograms after the 1-year period for evaluating the progression of the coronary lesions. The modified Gensini score was adopted for assessing coronary lesions while the HOMA-IR method was utilized for determining the state of their insulin resistance. Baseline characteristics and laboratory test results were described and the binomial regression analysis was conducted to investigate the relationship between insulin resistance and coronary atherosclerotic plaque progression. RESULTS: Index and follow-up Gensini scores were similar between the higher insulin lower insulin resistant groups (9.09 ± 14.33 vs 9.44 ± 12.88, p = 0.813 and 17.21 ± 18.46 vs 14.09 ± 14.18, p =0.358). However the Gensini score assessing coronary lesion progression between both visits was significantly elevated in the higher insulin resistant group (8.13 ± 11.83 versus 4.65 ± 7.58, p = 0.019). Multivariate logistic binomial regression analysis revealed that insulin resistance (HOMA-IR > 3.4583) was an independent predictor for coronary arterial plaque progression (OR = 4.969, p = 0.011). We also divided all the participants into a diabetic (n = 136) and a non-diabetic group (n = 230), and HOMA-IR remained an independent predictor for atherosclerosis plaque progression. CONCLUSIONS: Insulin resistance is an independent predictor of atherosclerosis plaque progression in patients with coronary heart disease in both the diabetic and non-diabetic population
Unique allosteric effect driven rapid adsorption of carbon dioxide on a new ionogel [P4444][2-Op]@MCM-41 with excellent cyclic stability and loading-dependent capacity
Allosteric effect-driven rapid stepwise CO2 adsorption of pyridine-containing anion functionalized ionic liquid [P4444][2-Op] confined into mesoporous silica MCM-41.</p
ImageCAS: A Large-Scale Dataset and Benchmark for Coronary Artery Segmentation based on Computed Tomography Angiography Images
Cardiovascular disease (CVD) accounts for about half of non-communicable
diseases. Vessel stenosis in the coronary artery is considered to be the major
risk of CVD. Computed tomography angiography (CTA) is one of the widely used
noninvasive imaging modalities in coronary artery diagnosis due to its superior
image resolution. Clinically, segmentation of coronary arteries is essential
for the diagnosis and quantification of coronary artery disease. Recently, a
variety of works have been proposed to address this problem. However, on one
hand, most works rely on in-house datasets, and only a few works published
their datasets to the public which only contain tens of images. On the other
hand, their source code have not been published, and most follow-up works have
not made comparison with existing works, which makes it difficult to judge the
effectiveness of the methods and hinders the further exploration of this
challenging yet critical problem in the community. In this paper, we propose a
large-scale dataset for coronary artery segmentation on CTA images. In
addition, we have implemented a benchmark in which we have tried our best to
implement several typical existing methods. Furthermore, we propose a strong
baseline method which combines multi-scale patch fusion and two-stage
processing to extract the details of vessels. Comprehensive experiments show
that the proposed method achieves better performance than existing works on the
proposed large-scale dataset. The benchmark and the dataset are published at
https://github.com/XiaoweiXu/ImageCAS-A-Large-Scale-Dataset-and-Benchmark-for-Coronary-Artery-Segmentation-based-on-CT.Comment: 17 pages, 12 figures, 4 table
Tanshinone IIA Protects against Dextran Sulfate Sodium- (DSS-) Induced Colitis in Mice by Modulation of Neutrophil Infiltration and Activation
Neutrophils play a critical role in the initiation and maintenance of intestinal inflammation. However, conventional neutrophil-targeted therapies can impair normal host defense. Tanshinone IIA has been recently revealed to act directly on neutrophils. Hence, we aimed at investigating whether Tanshinone IIA can protect against experimental colitis through modulation of neutrophils. We induced colitis in C57BL/6 mice by giving 3% dextran sulfate sodium (DSS) orally, and meanwhile, we treated mice daily with Tanshinone IIA intraperitoneally. The severity of colitis was evaluated by calculating disease activity index (DAI) and histological parameters. Neutrophil infiltration and activation in the colons of mice were measured. Moreover, whether Tanshinone IIA has direct effects on neutrophil migration and activation was determined in vitro. Our data showed that Tanshinone IIA significantly ameliorated the severity of DSS-induced colitis in mice, evidenced by the reduced DAI and improved colonic inflammation. In addition, Tanshinone IIA decreased neutrophil infiltration of intestinal mucosa and activation and reduced colonic inflammatory cytokines in DSS-treated mice. Furthermore, Tanshinone IIA was demonstrated to significantly suppress neutrophil migration and activation. These results provide compelling evidence that Tanshinone IIA has a therapeutic potential for alleviating inflammatory colitis in mice, which is possibly mediated by the immunomodulation of neutrophils
The safety and clinical outcomes of endovascular treatment versus microsurgical clipping of ruptured anterior communicating artery aneurysms: a 2-year follow-up, multicenter, observational study
Background and objectiveCurrent data on the optimal treatment modality for ruptured anterior communicating artery (AComA) aneurysms are limited. We conducted this multicenter retrospective study to evaluate the safety and clinical outcomes of endovascular treatment (EVT) and microsurgical clipping (MC) for the treatment of ruptured AComA patients.MethodsPatients with ruptured AComA aneurysms were screened from the Chinese Multicenter Cerebral Aneurysm Database. Propensity score matching (PSM) was used to adjust for baseline characteristic imbalances between the EVT and MC groups. The safety outcomes included total procedural complications, procedure-related morbidity/death and remedial procedure for complication. The primary clinical outcome was 2-year functional independence measured by the modified Rankin scale (mRS) score.ResultsThe analysis included 893 patients with ruptured AComA aneurysms (EVT: 549; MC: 346). PSM yielded 275 pairs of patients in the EVT and MC cohorts for comparison. Decompressive craniectomy being more prevalent in the MC group (19.3% vs. 1.5%, p < 0.001). Safety data revealed a lower rate of total procedural complications (odds ratio [OR] = 0.62, 95% CI 0.39–0.99; p = 0.044) in the EVT group and similar rates of procedure-related morbidity/death (OR = 0.91, 95% CI 0.48–1.73; p = 0.880) and remedial procedure for complication (OR = 1.35, 95% CI 0.51–3.69, p = 0.657) between the groups. Compared with that of MC patients, EVT patients had a greater likelihood of functional independence (mRS score 0–2) at discharge (OR = 1.68, 95% CI 1.14–2.50; p = 0.008) and at 2 years (OR = 1.89, 95% CI 1.20–3.00; p = 0.005), a lower incidence of 2-year all-cause mortality (OR = 0.54, 95% CI 0.31–0.93; p = 0.023) and a similar rate of retreatment (OR = 1.00, 95% CI 0.23–4.40; p = 1.000).ConclusionClinical outcomes after treatment for ruptured AComA aneurysms appear to be superior to those after treatment with MC, with fewer overall procedure-related complications and no increase in the retreatment rate. Additional studies in other countries are needed to verify these findings
- …