Shaw Voon Wong

Optimization of fuzzy rules design using genetic algorithm

Abstract Fuzzy rules optimization is a crucial step in the development of a fuzzy model. A simple two inputs fuzzy model will have more than ten thousand possible combinations of fuzzy rules. A fuzzy designer normally uses intuition and trial and error method for the rules assignment. This paper is devoted to the development and implementation of genetic optimization library (GOL) to obtain the optimum set of fuzzy rules. In this context, a fitness calculation to handle maximization and minimization problem is employed. A new fitness-scaling mechanism named as Fitness Mapping is also developed. The developed GOL is applied to a case study involving fuzzy expert system for machinability data selection (Wong SV, Hamouda AMS, Baradie M. Int J Flexi Automat Integr Manuf 1997;5(1/2):79–104). The main characteristics of genetic optimization in fuzzy rule design are presented and discussed. The effect of constraint (rules violation) application is also presented and discussed. Finally, the developed GOL replaces the tedious process of trial and error for better combination of fuzzy rules.

The development of an online knowledge-based expert system for machinability data selection

Abstract The development and implementation of an online knowledge-based system for machinability data selection is presented. Fuzzy logic has been incorporated as the reasoning mechanism behind the system. The system has been developed using object oriented programming, dynamic link library and Active-X control. It has been incorporated and tested into Internet and Intranet environment. Possible implementations of the system are suggested to work on real-world environment. A simplified fuzzy set-handling object has been developed in order to save resources. Weighted-centroid rather than union centroid has been used in output defuzzification. Comparison between these two methods is made and discussed.

Simulation of motorcyclist's kinematics during impact with W-Beam guardrail

W-Beam guardrail system has been in use as a standard for roadside safety barrier since 1950s. Recently, its safety performance standard has been upgraded to absorb impact from large vehicles. This performance standard requires guardrail system to be capable of capturing and redirecting a large range of vehicle types and sizes but its effects on safety of motorcyclists are not yet understood.The paper describes a three-dimensional computer simulation of the kinematics impact of motorcycle and dummy rider with W-Beam guardrail inclined at angles 45 and 90° to the initial direction of travel. The simulation is based on the test procedure recommended by ISO 13232 on the configurations for motorcycle-car impact. The focus of this study is not on the motorcycle change in velocity, but on the riders kinematics and acceleration vs. time history.Multibody model of motorcycle and finite element model of guardrail were developed in commercially available software. The simulation results are presented in this paper in form of kinematics and acceleration vs. time history.

Crashes with roadside objects along motorcycle lanes in Malaysia

Exclusive motorcycle lanes were introduced in Malaysia in the 1980s to reduce motorcyclist fatalities and they seem to be effective. However, no design guide has yet been developed for designing safer exclusive motorcycle lanes. The construction of Malaysian exclusive motorcycle lanes is based on the design criteria for cycle tracks [6], which does not suit the fast travelling and high volume of motorcycles along the exclusive lanes. According to the collected accident data, frequent motorcycle crashes still occur on exclusive motorcycle lanes. The present study found that roadside objects are one of the main contributing factors to motorcyclist fatalities. As a standard practice, guardrails have been planted along highways and roads. The design engineer of exclusive motorcycle lanes utilised the same practice and planted standard guardrails along exclusive motorcycle lanes. The suitability and the importance of the standard guardrail system as protection agent have been investigated and supported by real-world crash data. The catchment areas of the study were the top two longest exclusive motorcycle lanes in Malaysia: the exclusive motorcycle lanes along Federal Highway F0002 and the exclusive motorcycle lane along Shah Alam Expressway. Crash cases collected over 4½-year period were from the accident database of the authorities. A total number of 107 cases were recorded as motorcycle crashes involving roadside objects. Guardrails have been identified as the most struck object, representing 32.7% of all roadside object-related motorcycle crashes along exclusive motorcycle lanes. An odds ratio analysis has found that narrow surface objects contribute to higher fatality rate than guardrails. However, guardrails still contribute 23.5% of all fatal roadside object-related crashes and were found to be 1.7 times more likely to cause serious injury to motorcyclists than non-object-related motorcycle crashes. These findings support that guardrails are suitable to be used as a protection agent for the motorcyclists using the exclusive motorcycle lanes. However, further research and enhancements on the guardrail design system and material type are needed to have safer exclusive motorcycle lanes.

Factors related to seatbelt-wearing among rear-seat passengers in Malaysia

The benefit of wearing a rear seatbelt in reducing the risk of motor vehicle crash-related fatalities and injuries has been well documented in previous studies. Wearing a seatbelt not only reduces the risk of injury to rear-seat passengers, but also reduces the risk of injury to front-seat occupant who could be crushed by unbelted rear-seat passengers in a motor vehicle crash. Despite the benefits of wearing a rear seatbelt, its rate of use in Malaysia is generally low. The objective of this study was to identify factors that are associated with the wearing of a seatbelt among rear-seat passengers in Malaysia. Multinomial logistic regression analysis of the results of a questionnaire survey of 1651 rear-seat passengers revealed that rear-seat passengers who were younger, male, single and less educated and who had a perception of a low level of legislation enforcement, a lower risk-aversion and less driving experience (only for passengers who are also drivers) were less likely to wear a rear seatbelt. There was also a significant positive correlation between driver seatbelt and rear seatbelt-wearing behaviour. This implies that, in regards to seatbelt-wearing behaviour, drivers are more likely to adopt the same seatbelt-wearing behaviour when travelling as rear-seat passengers as they do when driving. These findings are crucial to the development of new interventions to increase the compliance rate of wearing a rear seatbelt.

THE MALAYSIAN GOVERNMENT'S ROAD ACCIDENT DEATH REDUCTION TARGET FOR YEAR 2010

Objective: This paper makes a projection of the vehicle ownership rate to the year 2010 and to use this projection to predict road accident deaths in year 2010. The projection served as an indicator for the Malaysian government to achieve a 4 road accident deaths per 10,000 vehicles safety target in year 2010. Method: The study included the prediction of vehicle ownership and the analysis of past trends in the road accident death rate. Gompertz growth model was used to project vehicle ownership and the prediction of road accident death rate was done using Autoregressive Integrated Moving Average (ARIMA) model with transfer noise function. Results and Conclusions: The Gompertz model predicted that vehicle ownership would be equal to 0.4409 by the year 2010. The road accident death rate is projected to decrease to 4.22 in year 2010, at an average decline rate of 2.14% per annum. This result suggests that a minimum 2.18% reduction per annum is required to achieve the national target in year 2010.

Relationship between cervical spine injury and helmet use in motorcycle road crashes

Motorcycle helmets have been proven to prevent head injury and reduce fatality in road crashes. However, certain studies indicate that the helmet increases the mass to the head, and thus the potential of neck injury due to the flexion/extension of the head–neck segment in a road crash may increase. This study was conducted to evaluate the effects of motorcycle helmets and the ways in which the accidents that occurred affected the incidence of cervical spine injury. Nevertheless, it is not intended to and does not discredit the fact that helmet use prevents many motorcyclists from sustaining serious and fatal head injuries. A total of 76 cases were collected and analyzed based on the data collected from real-world crashes. The Abbreviated Injury Scale (AIS) was used to assess the severity of injury, whereas the statistical Pearson χ2 correlation method was used for analysis. The results showed that motorcycle helmets did not affect the severity of cervical spine injury. However, when the samples were further subcategorized into different crash modes, it was found that helmets affect the incidence of a severe cervical spine injury. In frontal collisions, the use of helmets significantly reduces the severity of cervical spine injury, whereas in rear-end, side impact, and skidded accidents, the use of helmets increases the probability of a severe cervical spine injury. However, in the latter crash modes, a motorcyclist without a helmet will have to trade-off with head injury. A logistic regression model has been developed with respective crash modes and the probabilities of risk in having severe cervical spine injury have been calculated. Future designs in motorcycle helmets should therefore consider the significance of nonfrontal accidents and the interaction of helmet with other parts of the body by possibly considering the weight of the helmet.

Design of motorcyclist-friendly guardrail using finite element analysis

Conventional barrier systems have performed well for occupants of passenger cars and trucks, but their effects on other road user groups, especially motorcyclists, usually result in greater injuries. This study is purposed to improve the safety features of an existing guardrail system with regard to motorcyclists. It is aimed to reduce the severity of injuries sustained by the motorcyclists during the event of impact and containing the motorcycles and the riders. There is a relative lack of published materials regarding the nature of motorcycle collisions with roadside barriers. Various features of existing guardrail systems particularly the barrier posts were identified in the literature, presenting significant risks to fallen motorcyclists. Numerous strategies have been employed to better protect the motorcyclists from impacts with guardrails. The present study has employed polypropylene as material coupled with V-profile rails to give the new guardrail design. Weighing procedures were also conducted to determine the centre of gravity of the motorcycle. Three-dimensional computer models which consist of a newly designed V-beam guardrail and equivalent kinetic characteristics of a motorcycle were developed. The event of collision between the motorcycle and the guardrail was then simulated using computer finite element program, Algor. The simulations were conducted for three impact configurations, with the impact angle between the motorcycle and the guardrail at 90°, 45° and 20° at an impact velocity of 60 km/h. The results show the newly designed V-beam guardrail has more forgiving and better energy-absorbed characteristics than the existing design the conventional W-beam design.

Computational simulation of frontal impact of motorcycle telescopic fork

ABSTRACT This paper presents modelling aspects of a high fidelity finite element model of a motorcycle telescopic fork. For validation purpose, a series of impact tests of which a frontal impact load imposed on the individual fork by a rigid striker was conducted using factorial experiment approach. The model was then used to simulate all the impacts accordingly. The outcomes were evaluated in terms of permanent deformations of the fork, energy dissipated in the impact, and the velocity and displacement time histories of the striker. The overall performance and sensitivity of the model was also assessed using the factorial analysis. The deviations of time histories data were quantified by mean error, mean absolute error and root mean square error. The key responses of the fork were found to be successfully simulated and compared well to the test results. The computed largest value among the respective metrics over the total errors was 6.2% of which corresponding to the root mean square error of the displacement time histories data, whereas others were less than 3%. It is thus concluded that the fork model has been successfully validated and the modelling methods has been established. Recommendations for improvements were also given in the paper.

Kinematic Contact-Impact Algorithm with Friction

Abstract This paper is devoted to the development of kinematic contact-impact algorithm for impact problems. The developed algorithm is based on conservation of momentum and coefficient of restitution. Node-node and node-element contacts are formulated. The algorithm includes a novel method for handling potential voids and overlaps at contact intersection. Rigid Coulombs friction model is incorporated to handle sliding conditions. The developed kinematic contact-impact algorithm is incorporated into an explicit finite difference code previously developed by the authors. To validate the developed contact-impact algorithm, some numerical examples are illustrated. Comparisons between the kinematic contact algorithm and the exact solutions are made.