Design and Optimization for the Occupant Restraint System of Vehicle Based on a Single Freedom Model

Throughout the vehicle crash event, the interactions between vehicle, occupant, restraint system (VOR) are complicated and highly non-linear. CAE and physical tests are the most widely used in vehicle passive safety development, but they can only be done with the detailed 3D model or physical samples. Often some design errors and imperfections are difficult to correct at that time, and a large amount of time will be needed. A restraint system concept design approach which based on single-degree-of-freedom occupant-vehicle model (SDOF) is proposed in this paper. The interactions between the restraint system parameters and the occupant responses in a crash are studied from the view of mechanics and energy. The discrete input and the iterative algorithm method are applied to the SDOF model to get the occupant responses quickly for arbitrary excitations (impact pulse) by MATLAB. By studying the relationships between the ridedown efficiency, the restraint stiffness, and the occupant response, the design principle of the restraint stiffness aiming to reduce occupant injury level during conceptual design is represented. Higher ridedown efficiency means more occupant energy absorbed by the vehicle, but the research result shows that higher ridedown efficiency does not mean lower occupant injury level. A proper restraint system design principle depends on two aspects. On one hand,the restraint system should lead to as high ridedown efficiency as possible, and at the same time, the restraint system should maximize use of the survival space to reduce the occupant deceleration level. As an example, an optimization of a passenger vehicle restraint system is designed by the concept design method above, and the final results are validated by MADYMO, which is the most widely used software in restraint system design, and the sled test. Consequently, a guideline and method for the occupant restraint system concept design is established in this paper.

Development of Shallow Footing Anti-Ram Bollard System Through Modeling and Testing

In past terrorist attacks, vehicle borne improvised explosive devices (VBIED) have been the primary manner of attacking buildings and infrastructures. Preventing unauthorized vehicles from approaching a protected area with anti-ram systems would maintain an established standoff distance against moving and stationary vehicles and consequently reduce blast and debris threats. This strategy has been considered the first line of defence against terrorists. Several types of anti-ram devices have been developed in accordance with U. S. Department of State K-rating criteria, for example, wedge barriers, rising beams, sliding/swing gates, and drop arms. However, these devices typically need a deep foundation for installation and can't be implemented into many locations where a depth of excavation is limited in order to protect utility lines of buildings and infrastructures. This paper presents a recent development of a series of shallow footing anti-ram bollard systems (SFABS) that can satisfy K-12 rating with only five-inch thick footing. A high-fidelity physics based finite element technique with a vehicle crash model is used for predicting anti-ram capacity and determining design parameters of the SFABS. Full-scale vehicle crash tests of the developed SFABS systems have been carried out to validate the design and analysis.

The Emergency Department Crash Cart: A systematic review and suggested contents

BACKGROUND: As the field of Emergency Medicine grows worldwide, the importance of an Emergency Department Crash Cart(EDCC) has long been recognized. Yet, there is paucity of relevant peer-reviewed literature specifically discussing EDCCs or proposing detailed features for an EDCC suitable for both adult and pediatric patients. METHODS: The authors performed a systematic review of EDCC-specific literature indexed in Pubmed and Embase on December 20, 2016. In addition, the authors reviewed the 2015 American Heart Association(AHA) guidelines for cardiopulmonary resuscitation and emergency cardiovascular care, the 2015 European Resuscitation Council(ERC) guidelines for resuscitation, and the 2013 American College of Surgeons(ACS) Advanced Trauma Life Support(ATLS) 9 th edition.RESULTS: There were a total of 277 results, with 192 unique results and 85 duplicates. After careful review by two independent reviewers, all but four references were excluded. None of the four included articles described comprehensive contents of equipment and medications for both the adult and pediatric populations. This article describes in detail the final four articles specific to EDCC, and proposes a set of suggested contents for the EDCC. CONCLUSION: Our systematic review shows the striking paucity of such a high impact indispensable item in the ED. We hope that our EDCC content suggestions help enhance the level of response of EDs in the resuscitation of adult and pediatric populations, and encourage the implementation of and adherence to the latest evidence-based resuscitation guidelines.

IMPLEMENTATION TECHNIQUE RESEARCH FOR MAIN MEMORY DATABASE SYSTEM

The development of techniques in hardware makes it possible to implement MMDBMS.More and more requirements from realtime transaction processing see its broad application in the near future.This paper examines several techniques in the implementation of MMDBMS and then gives the design of TMMDBMS which is a prototype.

Development of an occupant restraint system model and parametric study on equivalent crash pulse in vehicle frontal offset crash

Studies were conducted to evaluate driver injury metrics with varying crash pulse in offset crash. First, a vehicle finite element （ FE ） model and an occupant restraint system （ORS） model were developed and validated against tests; then, the crash pulse collected from the test vehicle was equivalent to a dual-trapezoid shape pulse which will be quantitatively described by six parameters and was put into the ORS model; finally, parametric studies were conducted to analyze the sensitivi- ties of parameters of equivalent crash pulse on head resultant acceleration, head injury criteria （HIC）, neck axial force and chest deformation. Results showed that the second peak value of the crash pulse was statistically significant on all these injury criteria （P = 0. 001, 0. 000, 0. 000, 0. 000 re- spectively）, the first peak level had a negative significantly effect on all the criteria aforementioned except the chest deformation （P = 0. 011, 0. 038, and 0. 033 respectively）, and the interaction of the time-points of first and second peak values had a significant influence on head resultant acceleration （P = 0. 03 ）. A higher first peak value and a lower second peak value of the crash pulse could bring deeply lower injury metrics.

A dynamic crash recovery scheme for distributed real-time database systems

Recovery performance in the event of failures is very important for distributed real-time database systems. This paper presents a time-cognizant logging-based crash recovery scheme （TCLCRS） that aims at distributed real-time databases, which adopts a main memory database as its ground support. In our scheme, each site maintains a real-time log for local transactions and the subtransactions, which execute at the site, and execte local checkpointing independently. Log records are stored in non-volatile high- speed store, which is divided into four different partitions based on transaction classes. During restart recovery after a site crash, partitioned crash recovery strategy is adopted to ensure that the site can be brought up before the entire local secondary database is reloaded in main memory. The partitioned crash recovery strategy not only guarantees the internal consistency to be recovered, but also guarantee the temporal consistency and recovery of the sates of physical world influenced by uncommitted transactions. Combined with two- phase commit protocol, TCLCRS can guarantee failure atomicity of distributed real-time transactions.

Understanding the Occurrence of Two Total Floats in One Activity and Schedule Crashing Approaches for That Situation

Critical Path Method (CPM) Scheduling has proven to be an effective project management tool. However, teaching the topic has proven difficult to include all elements of CPM yet keep it simple enough for students to understand. In an effort to simplify the teaching of critical path method scheduling, the issue of two total floats in an activity does not get the attention necessary to address its occurrence. The objective of this paper is to present a mathematical method to show multiple total floats are possible for an activity. Also presented are suggestions for schedule crashing when multiple total floats are found. Two totals floats can be found if constraints (Lag or Lead) or non-Finish-to-Start (FS) relationships, or both are used in a network diagram. Situations are possible where an activity may have a start total float (STF) of zero but have a finish total float (FTF) greater than zero, or vice versa. Because the critical path generally follows the zero total float, these situations, where either the STF or the FTF is critical while the other is not, determines how the critical path activity must be controlled and crashed. This paper will present approaches of how to crash the schedule when a portion of the activity, either start or finish, is critical. Also presented will be methods to teach the subject matter with or without the use of scheduling software. Critical Path Method was revisited to see what the minimal conditions are needed to have activities with two total float. Generalized crashing methods were studied to see if the methods can be used when two total floats exist.

Carbon emission trading system and stock price crash risk of heavily polluting listed companies in China:based on analyst coverage mechanism

This study reveals the inconsistencies between the negative externalities of carbon emissions and the recognition condition of accounting statements.Hence,the study identifies that heavily polluting enterprises in China have severe off-balance sheet carbon reduction risks before implementing the carbon emission trading system(CETS).Through the staggered difference-in-difference(DID)model and the propen-sity score matching-DID model,the impact of CETS on reducing the risk of stock price crashes is examined using data from China’s A-share heavily polluting listed companies from 2007 to 2019.The results of this study are as follows:(1)CETS can significantly reduce the risk of stock price crashes for heavily polluting companies in the pilot areas.Specifically,CETS reduces the skewness(negative conditional skewness)and down-to-up volatility of the firm-specific weekly returns by 8.7%and 7.6%,respectively.(2)Heterogeneity analysis further shows that the impacts of CETS on the risk of stock price crashes are more significant for heavily polluting enterprises with the bear market condition,short-sighted management,and intensive air pollution.(3)Mechanism tests show that CETS can reduce analysts’coverage of heavy polluters,reducing the risk of stock price crashes.This study reveals the role of CETS from the stock price crash risk perspective and helps to clarify the relationship between climatic risk and corporate financial risk.

Automobile Crash Investigation Based on Vehicle System Related Causes: Systematic Literature Review

Automobile accidents are one of the leading causes of death worldwide. Every year, over 1.24 million people are killed in traffic accidents. Even though automobiles are designed to help people, they have been used to kill them in large numbers. Automobile accident research has primarily focused on past tragedies to develop and implement policies to combat this pandemic. The aim of this systematic review is to assess the different methods used to investigate the vehicle system-related cause factors of road traffic accidents. Police report reports have served as a foundation for providing historical facts about the causes of automobile accidents. It has been observed that police reports have limitations when it comes to reporting the involvement of vehicle systems in causing a traffic accident. The majority of the research was conducted on articles that investigated vehicle system risk factors using statistical data. Following articles that used statistical data to investigate vehicle system risk factors, the inclusion criteria were chosen. Articles on traffic accidents published in Cameroon were included on the condition that they studied at least one traffic accident risk factor. Two hundred twenty-five distinct records were identified, and 155 full texts were screened for inclusion, resulting in the inclusion of 25 studies in the review. According to the findings, failure to break the braking system, tyre puncture, poor driving, speeding, and overtaking are the leading causes of automobile crash reports reported by police. The majority of the study’s conclusions lamented that accusing vehicle systems was based on assumptions and the reporter’s judgment. It was determined that the use of stringent vetting procedures to investigate vehicle systems is the cause of a traffic accident. As a result, stakeholders will require accurate facts from a traffic crash investigation.

Evaluation of Roadside Wrong-Way Warning Systems with Different Types of Sensors

Driving the wrong way on motorways has been a nagging traffic safety problem all over the world. In order to reduce wrong-way driving incidents and crashes, roadside wrong-way warning systems applying advanced ITS （intelligent transportation systems） technologies have been adopted and deployed for the first time at 24 rest areas on motorways in Japan since 2008. The systems are used to detect wrong-way vehicles and warn the drivers of their wrong-way driving at the off-ramps to the rest areas. This paper describes an evaluation of the roadside wrong-way warning systems with four different types of sensors from the viewpoint of detection accuracy and effectiveness in preventing wrong-way driving. The sensing technology includes microwave Doppler radar, ultrasonic sensor, photoelectric sensor and video image processing technology.

对象驱动的Linux内核crash分类技术研究

Crash(程序崩溃)分析是漏洞挖掘与利用的关键阶段,精准的crash分类是crash分析和漏洞利用的前提.针对现有的Linux内核crash存在大量重复的问题,本文提出一种对象驱动的Linux内核crash分类方法.该方法将内核crash与内核对象的关系建模为二部图结构,从而将crash分类问题转化为内核对象的相似性对比问题.首先,通过对crash执行后向污点分析提取crash相关的内核对象;其次,构造内核对象调用图计算内核与根本原因的相关性度量;最后,基于上述结果构造二部图实现crash相似性比较算法.基于上述方法,本文开发出了Linux内核crash分类的原型系统.通过在真实的数据集上进行实验,验证了系统的有效性和可用性,弥补了现有分类方法粒度较粗,存在误报较多的问题.

Injuries Associated with Auto-Tricycle Crashes in an African City: Incidence and Pattern

Purpose: The aim of this study was to determine the incidence and pattern of injuries resulting from auto-tricycle crashes among patients in a tertiary referral centre in Ghana. Methods: Data were retrospectively extracted from hospital records of patients who got involved in auto-tricycle crashes and presented to the Accident and Emergency Centre of the Komfo Anokye Teaching Hospital (KATH), over a one-year period using a structured questionnaire. The gathered data were then entered into an electronic database and then analysed with SPSS version 20.0. Results: The incidence of injury following auto-tricycle crashes over the one-year period was 5.9% (95% CI: 4.9% - 7.0%) with a case fatality rate (FR) of 3.8% (95% CI: 1.3% - 8.7%). All the mortalities resulted from head and neck injuries and none of the patients involved wore a crash helmet. Only 5% of those studied wore crash helmets and were all drivers. Closed fractures accounted for 58% of the injuries, followed by open fractures, 28%. The most commonly fractured bones were the tibia/fibula, followed by the femur and then radius/ulna. The most common mechanism of injury was auto-tricycle toppling over (29%). Passengers were the most injured (48%), followed by drivers (37%) and pedestrians (15%). Most (72%) injuries among participants involved a single body part. On the injury severity scale, most (61%) of patients had minor trauma and 38% had major trauma. Conclusion: Auto-tricycle crashes account for 5.9% of injuries at the study site with a case fatality rate of 3.8%. Passengers had a higher injury rate (48%) than drivers (37%). Fractures of the tibia/fibula were most commonly associated with auto-tricycle crashes. Injuries to the head and neck were responsible for the deaths in the study participants and non-use of a crash helmet was associated with mortalities.

Impact of COVID-19 on Safety Performance for Motorcycles: Pre-and during-Pandemic Conditions

Florida has the highest number of motorcycle fatalities in the United States and contains the second largest population of registered motorcycles. The COVID-19 pandemic influenced the roads, traffic, and driving behavior in the continental United States. Motorcycle crashes decreased during the COVID-19 years (2020 and 2021) while the fatality rates increased. The purpose of this study is to 1) investigate motorcycle crashes before and during the Pandemic period to understand the impacts on motorcycle safety and contributing factors to the crash severity levels;2) develop the crash predictive model for different degrees of severity in motorcycle crashes in Florida. Florida statewide crash data were collected. T tests have been conducted to compare the contributing factors between two periods. The injury severities are significantly different among all five levels between those during normal period and the Pandemic period. A crash predictive model has been developed to determine the facts to injury severity levels for motorcycle crashes. A total of eight variables are found to significantly increase the injury severity levels for motorcycle crashes during the Pandemic period.

A Multilayer Perceptron Artificial Neural Network Study of Fatal Road Traffic Crashes

This paper examines the relationship between fatal road traffic accidents and potential predictors using multilayer perceptron artificial neural network (MLANN) models. The initial analysis employed twelve potential predictors, including traffic volume, prevailing weather conditions, roadway characteristics and features, drivers’ age and gender, and number of lanes. Based on the output of the model and the variables’ importance factors, seven significant variables are identified and used for further analysis to improve the performance of models. The model is optimized by systematically changing the parameters, including the number of hidden layers and the activation function of both the hidden and output layers. The performances of the MLANN models are evaluated using the percentage of the achieved accuracy, R-squared, and Sum of Square Error (SSE) functions.

An In-Depth Analysis of Road Fatal Crash Patterns and Discussions in Ho Chi Minh City

Although there has been a slight decrease in road traffic crashes, fatalities, and injuries in recent years, HCMC (Ho Chi Minh City) will continue to encounter challenges in mitigating and preventing road crashes. This study analyzes road crash data from the past five years, obtained from the Road-Railway Police Bureau (PC08) and TSB (Traffic Safety Board) in HCMC. This analysis gives us valuable insights into road crash patterns, characteristics, and underlying causes. This comprehensive understanding serves as a scientific foundation for developing cohesive strategies and implementing targeted solutions to address road traffic safety issues more effectively in the future.

A Workable Solution for Reducing the Large Number of Vehicle and Pedestrian Accidents Occurring on a Yellow Light

Traffic intersections are incredibly dangerous for drivers and pedestrians. Statistics from both Canada and the U.S. show a high number of fatalities and serious injuries related to crashes at intersections. In Canada, during 2019, the National Collision Database shows that 28% of traffic fatalities and 42% of serious injuries occurred at intersections. Likewise, the U.S. National Highway Traffic Administration (NHTSA) found that about 40% of the estimated 5,811,000 accidents in the U.S. during the year studied were intersection-related crashes. In fact, a major survey by the car insurance industry found that nearly 85% of drivers could not identify the correct action to take when approaching a yellow traffic light at an intersection. One major reason for these accidents is the “yellow light dilemma,” the ambiguous situation where a driver should stop or proceed forward when unexpectedly faced with a yellow light. This situation is even further exacerbated by the tendency of aggressive drivers to inappropriately speed up on the yellow just to get through the traffic light. A survey of Canadian drivers conducted by the Traffic Injury Research Foundation found that 9% of drivers admitted to speeding up to get through a traffic light. Another reason for these accidents is the increased danger of making a left-hand turn on yellow. According to the National Highway Traffic Safety Association (NHTSA), left turns occur in approximately 22.2% of collisions—as opposed to just 1.2% for right turns. Moreover, a study by CNN found left turns are three times as likely to kill pedestrians than right turns. The reason left turns are so much more likely to cause an accident is because they take a driver against traffic and in the path of oncoming cars. Additionally, most of these left turns occur at the driver’s discretion—as opposed to the distressingly brief left-hand arrow at busy intersections. Drive Safe Now proposes a workable solution for reducing the number of accidents occurring during a yellow light at intersections. We believe this fairly simple solution will save lives, prevent injuries, reduce damage to public and private property, and decrease insurance costs.

基于PAM-CRASH的鸟撞飞机风挡动响应分析

结合显式动力分析有限元软件PAM-CRASH及其提供的SPH算法,建立了鸟撞飞机风挡数值分析模型。对某飞机风挡进行了动响应分析,计算了风挡中轴线上四点位移时间曲线;鸟撞击过程的仿真结果表明,SPH鸟体模型能有效模拟撞击时鸟体溅射成碎片的情形;建立了鸟撞击作用下风挡破坏判据,对风挡在试验条件下是否破坏进行了模拟计算。计算结果和试验结果吻合较好,表明本文建立的鸟撞飞机风挡数值模型是有效的。

基于Pc-crash的交通事故再现误差分析

对交通事故再现软件Pc-crash中的特征参数进行分析,设计具普遍意义的车-车斜撞模型,运用分析法、控制变量法先提取较主要的参数;再设定正交试验将这些较重要参数按权重大小排序.基于对特征参数的研究,探求这些重要参数对模拟结果影响的权重及产生影响的类型,以此寻求减小事故再现误差的方法,并用国内一起典型的车-两轮车交通事故验证结论的正确性,为提高Pc-crasch软件再现国内事故精度的研究建立基础.

Selection of optimal U-turn locations for indirect driveway left-turn treatments on urban streets

The location of U-turn bays is an important consideration in indirect driveway left-turn treatments.In order to improve the performance of right-turns followed by U-turns（RTUTs）,this study evaluates the impacts of the separation distances between driveway exits and downstream U-turn locations on the safety and operational performance of vehicles making RTUTs.Crash data are investigated at 179 selected roadway segments,and travel time data are measured using video cameras at 29 locations in the state of Florida,USA.Crash rate models and travel time models are developed based on data collected in the field.It is found that the separation distance between driveway exits and downstream U-turn locations significantly impacts the safety and operational performance of vehicles making right turns followed by U-turns.Based on the research results,the minimum and optimal separation distances between driveways and U-turn locations under different roadway conditions are determined to facilitate driver use of RTUTs.The results of this study can be used for future intersection improvement projects in China.

交通事故再现碰撞模型综述

对当前国内外交通事故再现分析领域的研究背景和现况给予了介绍 ,并详细阐述了主流的各种碰撞模型 ,最后展望了其发展前景。