Development of a Crash Risk Index to Identify Real Time Crash Risks on Freeways

Chengcheng Xu,Pan Liu,Wei Wang,Xuan Jiang 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.7

The primary objective of this study is to develop a quantitative indicator that can be directly used to identify hazardous traffic states on freeway mainlines. Using data obtained from a 22-mile freeway segment on the I-880N freeway in San Francisco Bay Area in the United States, Fisher discriminant analysis was conducted to derive a linear combination of traffic flow parameters which can be used to distinguish traffic states which may lead to crashes from normal traffic conditions which were potentially safe. A new variable termed “crash risk index” was defined based on the discriminant function. A crash risk index which is smaller than 0 represents a hazardous traffic condition potentially leading to a crash. Accordingly, a crash risk index which is greater than 0 represents normal traffic conditions which, theoretically, will not lead to crash occurrences. The research team tested the prediction performance of using the crash risk index to identify hazardous traffic conditions on freeway mainlines. An overall prediction accuracy of about 65.7% was achieved. Conditional logistic regression analysis was then conducted to evaluate the impacts of crash risk indexes on the likelihood of crash occurrences. It was found that the likelihood of freeway crashes increased with the decreases in crash risk index. One unit decrease in crash risk index increased the risk of crash occurrence by 180.3%. The research team also looked extensively at the impacts of crash risk indexes at different time slices. It was found that the impacts of crash risk index decrease with time and the crash risk index at the time slice most immediately before crashes had the greatest impact on crash occurrences.

Analysis of E-bike Trip Duration and Frequency by Bayesian Duration and Zero-inflated Count Models

Chengcheng Xu,Chen Wang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

E-bike trip duration and frequency are two essential variables to identify factors affecting e-bike travel demand. This study aimed to investigate the factors affecting e-bike trip duration and frequency. The Bayesian hazard-based duration models with random effect were developed to investigate the contributing factors to the travel time of e-bike trip. The random effect was included to capture the unobserved heterogeneity. Estimation results showed that trip purpose, traffic volume, population, departure time, age and occupation are the main contributing factors to e-bike trip duration. And the factors affecting travel time of e-bike trip are distinct between males and females. The validation results indicated that the predictive performance of the developed duration models are satisfactory. The Bayesian zero-inflated count models with random effect were then used to investigate the contributing factors to the e-bike trip frequency. The zero-inflated count model assumes that the frequency of e-bike trip is generated by two states, including zero-frequency state which determines whether people use e-bikes for travel, and negative binomial state which determines e-bike trip frequency.

Utilizing Structural Equation Modeling and Segmentation Analysis in Real-time Crash Risk Assessment on Freeways

Chengcheng Xu,Dawei Li,Zhibin Li,Wei Wang,Pan Liu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7

The study aimed to utilize Structural Equation Modeling (SEM) and K-means clustering for predicting real-time crash risks onfreeways. The SEM was used to transform a number of correlated traffic variables into four independent latent traffic factors, and toestablish the interrelationships among the traffic variables and crash risks. The segmentation analysis based on K-means clusteringwas then conducted to investigate the main traffic factors affecting crash risks in various traffic regimes. It was found that: (a) Themeasurement equations in SEM can effectively account for the correlations among traffic variables by transforming numerouscorrelated traffic variables into several latent traffic variables; (b) The SEM can both capture the direct and indirect effects of trafficflow variables on crash risks. This promotes a better understanding how traffic conditions affect crash risks; (c) The SEM producesmore accurate estimates of crash risks than existing modeling technique. It can increase the crash prediction accuracy by an averageof 7.6% compared with the commonly used logistic regression; and (d) Segmentation analysis results suggested that the trafficfactors contributing to crash risks are various across different traffic regimes. The proactive crash prevention strategies for differenttraffic regimes were discussed based on the findings in the segmentation analysis

Sandwich Structure Electrode as Advanced Performance Anode for Lithium-Ion Batteries

Wei Chengcheng,Sun Xiaogang,Liang Guodong,Huang Yapan,Hu Hao,Xu Yuhao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

In this work, a sandwich structure electrode was prepared by a simple vacuum filtration and rolling process. The SEM showed that the active materials were uniformly embedded in the pores of the three-dimensional conductive network of the carbon nanotube (CNTs) conductive paper. The contact interface area of active material and the conductive network significantly increased and the interface resistance was greatly reduced. The porous anode can accommodate the volume expansion of the silicon and effectively alleviated pressed during cycle. The electrode also exhibited good stability in cycles. Electrochemical tests showed that the first discharge specific capacity of the sandwich electrode reached 2330 mAh/g with a coulombic efficiency of 86%. After 500 cycles, the specific capacity was still maintained at 1512 mAh/g. At a large current density of 2 A/g, the specific capacity hold was 840 mAh/g compared with the copper foil electrode of 100 mAh/g.

Analysis of decimation techniques to improve computational efficiency of a frequency-domain evaluation approach for real-time hybrid simulation

Tong Guo,Chengcheng,Weijie Xu 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.6

Accurate actuator tracking is critical to achieve reliable real-time hybrid simulation results for earthquake engineering research. The frequency-domain evaluation approach provides an innovative way for more quantitative post-simulation evaluation of actuator tracking errors compared with existing time domain based techniques. Utilizing the Fast Fourier Transform the approach analyzes the actuator error in terms of amplitude and phrase errors. Existing application of the approach requires using the complete length of the experimental data. To improve the computational efficiency, two techniques including data decimation and frequency decimation are analyzed to reduce the amount of data involved in the frequency-domain evaluation. The presented study aims to enhance the computational efficiency of the approach in order to utilize it for future on-line actuator tracking evaluation. Both computational simulation and laboratory experimental results are analyzed and recommendations on the two decimation factors are provided based on the findings from this study.

Epithelial CST1 Promotes Airway Eosinophilic Inflammation in Asthma via the AKT Signaling Pathway

Du Lijuan,Xu Changyi,Tang Kun,Shi Jia,Tang Lu,Lisha Xiao,Lei Chengcheng,Liu Huicong,Liang Yuxia,Guo Yubiao 대한천식알레르기학회 2023 Allergy, Asthma & Immunology Research Vol.15 No.3

Purpose: Epithelial cystatin SN (CST1), a type 2 cysteine protease inhibitor, was significantly upregulated in asthma. In this study, we aimed to investigate the potential role and mechanism of CST1 in eosinophilic inflammation in asthma. Methods: Bioinformatics analysis on Gene Expression Omnibus datasets were used to explore the expression of CST1 in asthma. Sputum samples were collected from 76 asthmatics and 22 control subjects. CST1 mRNA and protein expression in the induced sputum were measured by real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting. The possible function of CST1 was explored in ovalbumin (OVA)-induced eosinophilic asthma. Transcriptome sequencing (RNA-seq) was used to predict the possible regulated mechanism of CST1 in bronchial epithelial cells. Overexpression or knockdown of CST1 was further used to verify potential mechanisms in bronchial epithelial cells. Results: CST1 expression was significantly increased in the epithelial cells and induced sputum of asthma. Increased CST1 was significantly associated with eosinophilic indicators and T helper cytokines. CST1 aggravated airway eosinophilic inflammation in the OVA-induced asthma model. In addition, overexpression of CST1 significantly enhanced the phosphorylation of AKT and the expression of serpin peptidase inhibitor, clade B, member 2 (SERPINB2), while knockdown using anti-CST1 siRNA reversed the trend. Furthermore, AKT had a positive effect on SERPINB2 expression. Conclusions: Increased sputum CST1 may play a key role in the pathogenesis of asthma through involvement in eosinophilic and type 2 inflammation through activation of the AKT signaling pathway, further promoting SERPINB2 expression. Therefore, targeting CST1 might be of therapeutic value in treating asthma with severe and eosinophilic phenotypes.

Dose-Dense Rituximab-CHOP versus Standard Rituximab-CHOP in Newly Diagnosed Chinese Patients with Diffuse Large B-Cell Lymphoma: A Randomized, Multicenter, Open-Label Phase 3 Trial

Xueying Li,He Huang,Bing Xu,Hongqiang Guo,Yingcheng Lin,Sheng Ye,Jiqun Yi,Wenyu Li,Xiangyuan Wu,Wei Wang,Hongyu Zhang,Derong Xie,Jiewen Peng,Yabing Cao,Xingxiang Pu,Chengcheng Guo,Huangming Hong,Zhao 대한암학회 2019 Cancer Research and Treatment Vol.51 No.3

Purpose Rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone administered every 3 weeks (R-CHOP-21) is the standard care for diffuse large B-cell lymphoma (DLBCL). It is unknown whether the dose-dense R-CHOP (R-CHOP-14) could improve the outcome of the disease in Asian population. Materials and Methods Newly diagnosed DLBCL patients were centrally, randomly assigned (1:1) to receive R-CHOP- 14 or R-CHOP-21. R-CHOP-14 was administered every 2 weeks, and R-CHOP-21 was administered every 3 weeks. Primary end point was disease-free survival (DFS). Secondary end points included overall survival (OS), progression-free survival (PFS), response rate and toxicities. Results Seven hundred and two patients were randomly assigned to receive R-CHOP-14 (n=349) or R-CHOP-21 (n=353). With a median follow-up of 45.6 months, the two groups did not differ significantly in 3-year DFS (79.6% for R-CHOP-14 vs. 83.2% for R-CHOP-21, p=0.311), 3-year OS (77.5% for R-CHOP-14 vs. 77.6% for R-CHOP-21, p=0.903), or 3-year PFS (63.2% for R-CHOP-14 vs. 66.1% for R-CHOP-21, p=0.447). Patients with an International Prognostic Index (IPI) score ! 2 had a poorer prognosis compared to those with an IPI score < 2. Grade 3/4 hematologic and non-hematologic toxicities were manageable and similar between R-CHOP-14 and R-CHOP-21. Conclusion R-CHOP-14 did not improve the outcome of DLBCL compared to R-CHOP-21 in Asian population. With manageable and similar toxicities, both of the two regimens were suitable for Asian DLBCL patients. For high-risk patients with IPI ! 2, new combination regimens based on R-CHOP deserve further investigation to improve efficacy.

Stochastic Route Choice Based on VMS Information and Hierarchy for Urban Transport Network

Haoyang Ding,Min Yang,Wei Wang,Chengcheng Xu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

This paper firstly establishes four variational inequalities for stochastic traffic assignment by quantifying information utility of Variable Message Signs (VMS) and hierarchy of transport network. When VMS systems are operated in the higher level of roads such as arterials, the attenuation factor of information utility is integrated with information quantity to define a new formulation of the impact coefficient of VMS on traffic flow, which appears in the definitions of link and path lengths, and allocation parameters. Furthermore, equivalent Variational Inequalities (VIs) of Logit models considering these elements are developed and proved. A case study was conducted using the VI models on a hierarchical road network. We get some practically meaningful results, for example, VMS information can improve hierarchical network performance by interacting with traffic flow in all models except the C-Logit model and hierarchical level can improve network performance. Among the results, the most important is that the C-Logit or pathsize Logit will produce a flow pattern with less fluctuation of traffic densities among links and is less affected by stochastic factors than the multinomial Logit and cross-nested Logit in a stochastic hierarchical road network.

The natural product salicin alleviates osteoarthritis progression by binding to IRE1α and inhibiting endoplasmic reticulum stress through the IRE1α-IκBα-p65 signaling pathway

Zhu Zhenglin,Gao Shengqiang,Chen Cheng,Xu Wei,Xiao Pengcheng,Chen Zhiyu,Du Chengcheng,Chen Bowen,Gao Yan,Wang Chunli,Wang Chunli,Huang Wei 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Despite the high prevalence of osteoarthritis (OA) in older populations, disease-modifying OA drugs (DMOADs) are still lacking. This study was performed to investigate the effects and mechanisms of the small molecular drug salicin (SA) on OA progression. Primary rat chondrocytes were stimulated with TNF-α and treated with or without SA. Inflammatory factors, cartilage matrix degeneration markers, and cell proliferation and apoptosis markers were detected at the mRNA and protein levels. Cell proliferation and apoptosis were evaluated by EdU assays or flow cytometric analysis. RNA sequencing, molecular docking and drug affinity-responsive target stability analyses were used to clarify the mechanisms. The rat OA model was used to evaluate the effect of intra-articular injection of SA on OA progression. We found that SA rescued TNF-α-induced degeneration of the cartilage matrix, inhibition of chondrocyte proliferation, and promotion of chondrocyte apoptosis. Mechanistically, SA directly binds to IRE1α and occupies the IRE1α phosphorylation site, preventing IRE1α phosphorylation and regulating IRE1α-mediated endoplasmic reticulum (ER) stress by IRE1α-IκBα-p65 signaling. Finally, intra-articular injection of SA-loaded lactic-co-glycolic acid (PLGA) ameliorated OA progression by inhibiting IRE1α-mediated ER stress in the OA model. In conclusion, SA alleviates OA by directly binding to the ER stress regulator IRE1α and inhibits IRE1α-mediated ER stress via IRE1α-IκBα-p65 signaling. Topical use of the small molecular drug SA shows potential to modify OA progression.

Simulating and Analyzing the Effect on Travel Behavior of Residential Relocation and Corresponding Traffic Demand Management Strategies

Haoyang Ding,Min Yang,Wei Wang,Chengcheng Xu 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.2

Triggered by rapid urban expansion and fast population growth, a progressive residential relocation has occurred in most cities and its impacts on travel behavior have been confirmed in many studies. However, none has evaluated the effects of travel management strategies that relieves the side effects caused by this relocation. To this end, a multi-agent-based simulation model is proposed to assess the impacts of residential relocation on travel behavior and urban transportation in China. Based on the data in Tongling, China, the simulation on six scenarios is conducted to test how the residents in the urban center and suburbs are affected by different strategies, such as increased land diversity in suburbs, lowered growth in private car ownership and improved public transit accessibility. The results indicate that more daily trips would be lengthened and tend to be motorized by this residential relocation. The scenario test shows that compared to other strategies, policies that aims to reduce travel demand and trip distances after residential relocation have a better performance in traffic improvement.