Risk field modeling of urban tunnel based on APF.

OBJECTIVE: The purpose of this paper is to explore the changing laws of driving safety in the complex and changing driving environment in urban tunnels, to analyze the evolution of driving risk fields caused by changes in adjacent vehicles, driving behavior characteristics and road environment, and to reveal the formation mechanism of tunnel driving danger zones. METHODS: The kinetic field, behavioral field and potential field models are constructed according to the APF theory. The driving safety risks arising from the surrounding vehicles, driving behavior characteristics and changes in the tunnel environment are analyzed in the process of driving from the open section to the exit of the tunnel. RESULTS: The magnitude of the risk field force is inversely proportional to the spacing of the vehicles and the distance between the tunnel sidewalls, and is proportional to the relative speed between the vehicles and the slope of the longitudinal slope. Under the same conditions, the vehicle at the entrance and exit of the tunnel is subjected to a greater force of travel risk than inside the tunnel, and the effect of speed on the force of the risk field is greater than the distance. CONCLUSIONS: The established model better describes the trend of driving risk during the driving of vehicles in urban tunnels, and the research findings can provide theoretical support for the design and traffic management of urban tunnels.

Comparison of GRACE and TIMI risk scores in the prediction of in-hospital and long-term outcomes among East Asian non-ST-elevation myocardial infarction patients.

BACKGROUND: Risk stratification in non-ST segment elevation myocardial infarction (NSTEMI) determines the intervention time. Limited study compared two risk scores, the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) risk scores in the current East Asian NSTEMI patients. METHODS: This retrospective observational study consecutively collected patients in a large academic hospital between 01/01 and 11/01/2017 and followed for 4 years. Patients were scored by TIMI and GRACE scores on hospital admission. In-hospital endpoints were defined as the in-hospital composite event, including mortality, re-infarction, heart failure, stroke, cardiac shock, or resuscitation. Long-term outcomes were all-cause mortality and cardiac mortality in 4-year follow-up. RESULTS: A total of 232 patients were included (female 29.7%, median age 67 years), with a median follow-up of 3.7 years. GRACE score grouped most patients (45.7%) into high risk, while TIMI grouped the majority (61.2%) into medium risk. Further subgrouping the TIMI medium group showed that half (53.5%) of the TIMI medium risk population was GRACE high risk (≥ 140). Compared to TIMI medium group + GRACE < 140 subgroup, the TIMI medium + GRACE high-risk (≥ 140) subgroup had a significantly higher in-hospital events (39.5% vs. 9.1%, p < 0.05), long-term all-cause mortality (22.2% vs. 0% p < 0.001) and cardiac death (11.1% vs. 0% p = 0.045) in 4-year follow-up. GRACE risk scores showed a better predictive ability than TIMI risk scores both for in-hospital and long-term outcomes. (AUC of GRACE vs. TIMI, In-hospital: 0.82 vs. 0.62; long-term mortality: 0.89 vs. 0.68; long-term cardiac mortality: 0.91 vs. 0.67, all p < 0.05). Combined use of the two risk scores reserved both the convenience of scoring and the predictive accuracy. CONCLUSION: GRACE showed better predictive accuracy than TIMI in East Asian NSTEMI patients in both in-hospital and long-term outcomes. The sequential use of TIMI and GRACE scores provide an easy and promising discriminative tool in predicting outcomes in NSTEMI East Asian patients.