Development of a valve and optimization of a tube for self-inflating tire

Worldwide, the tire market requires safe and eco-friendly tires. In this study, a self-inflating tire (SIT) was studied and manufactured. Self-inflating tire refers to a technique for maintaining appropriate tire pressure. An internal regulator senses when tire inflation pressure has dropped below the set air pressure. The tire boosts air through the valve when rolling and compressed air enters into the tire. This procedure keeps the tire air pressure at an appropriate level and increases tire safety. In this study, a regulator was used as a negative-pressure system. A check valve was selected the minute flow check valve depending on the shape of the configured system. In addition, the material of the tube was developed with excellent physical properties and resistances (elastic rebound, working temperature, etc.) owing to its complete compression and restoration. A tube performance tester was developed and a computer aided engineering (CAE) model was modeled for comparison with the test results. Using the tester and model, it was possible to optimize the shape of the tube and regulator. Finally, the reliability of the study was verified through the prototype test. The developed equipment and systems can be used for the manufacture of high-performance and safe tires.     

Using kinematic driving data to detect sleep apnea treatment adherence

People spend a significant amount of time behind the wheel of a car. Recent advances in data collection facilitate continuously monitoring this behavior. Previous work demonstrates the importance of this data in driving safety but does not extended beyond the driving domain. One potential extension of this data is to identify driver states related to health conditions such as obstructive sleep apnea (OSA). We collected driving data and medication adherence from a sample of 75 OSA patients over 3.5 months. We converted speed and acceleration behaviors to symbols using symbolic aggregate approximation and converted these symbols to pattern frequencies using a sliding window. The resulting frequency data was matched with treatment adherence information. A random forest model was trained on the data and evaluated using a held-aside test dataset. The random forest model detects lapses in treatment adherence. An assessment of variable importance suggests that the important patterns of driving in classification correspond to route decisions and patterns that may be associated with drowsy driving. The success of this approach suggests driving data may be valuable for evaluating new treatments, analyzing side effects of medications, and that the approach may benefit other drowsiness detection algorithms.     

An ERP approach for container terminal operating systems

The major characteristics of ERP (Enterprise Resource Planning) are an enterprise-wide system that covers all the business functions and information resources, integrated database, built-in best industry practice, packaged software and open architecture. ERP enables reduction of system development time, flexibility, standardization of workflow and effective business planning capability. ERP is mainly for the manufacturing industry. However, the principles of ERP can also be applied to container terminal operating systems. This paper presents an ERP system approach for a container terminal. It has clustered the workflow of a container terminal and analysed the business process to generate the best workflows. The integrated database is designed to eliminate redundancy and keep integration. The core of ERP for container terminal is the planning facility such as berth planning and yard planning. The planning capability is very tightly coupled with data flow from client entities such as shipping companies. The ERP can handle the existing problems of container terminal operation that are mainly caused by lack of integration of a whole information resource in a container terminal, ad-hoc and poor planning capability, disconnected and incorrect data from client companies. The ERP approach can not only resolve the problems of container terminals but also promote adoption of information systems for container terminals in the world that have not yet implemented terminal operating systems.     

Evaluating the impacts of urban corridor traffic signal optimization on vehicle emissions and fuel consumption

This study investigates the impacts of traffic signal timing optimization on vehicular fuel consumption and emissions at an urban corridor. The traffic signal optimization approach proposed integrates a TRANSIMS microscopic traffic simulator, the VT-Micro model (a microscopic emission and fuel consumption estimation model), and a genetic algorithm (GA)-based optimizer. An urban corridor consisting of four signalized intersections in Charlottesville, VA, USA, is used for a case study. The result of the case study is then compared with the best traffic signal timing plan generated by Synchro using the TRANSIMS microscopic traffic simulator. The proposed approach achieves much better performance than that of the best Synchro solution in terms of air quality, energy and mobility measures: 20% less network-wide fuel consumption, 8–20% less vehicle emissions, and nearly 27% less vehicle-hours-traveled (VHT).     

Exploring the impacts of road surface texture on tyre/road noise - A case study in Hong Kong

The impacts of road surface texture on tyre/road noise are explored by analysing field data applying fast Fourier transform technique to tyre/road noise spectrum analysis. The results indicate that the tyre/road noise can be higher at lower frequency bands but lower at higher bands. Cluster analysis on surface texture in terms of wavelength identified three cluster groups that centred at 1.32 mm, 3.65 mm, and 5.11 mm have different impacts on noise. The shorter wavelength group suppressed tyre/road noise, medium group aggravated it and the high wavelength group were outliers.     

Knowledge management for maritime logistics value: discussing conceptual issues

This paper introduces the concept of maritime logistics value as one of the most significant strategic goals that maritime operators want to achieve. The value is reflected in operational efficiency (e.g. reducing lead time and business costs) and service effectiveness (e.g. flexibility, responsiveness and reliability in the service). Drawing from key theories and practices in strategic management such as knowledge-based perspective and social network embeddedness perspective, this paper adopts a knowledge management strategy as a way to create and sustain the maritime logistics value. A conceptual framework is established for the exploration of the way to acquire knowledge and the effectiveness of the acquired knowledge in maximising the maritime logistics value. Following the parameters of this framework, the positive relationship between social networks, knowledge acquisition and maritime logistics value is identified, and its relevant theoretical and practical implications are discussed.     

Objective evaluation of the sound quality of the warning sound of electric vehicles with a consideration of the masking effect: Annoyance and detectability

This study developed a method to evaluate the sound quality of the warning sound masked by background noise considering the masking effect. The warning sound of an electric vehicle is required by law for the safety of pedestrians. Therefore, the warning sound becomes an additional noise pollution source if it is designed as an annoyance. On the other hand, if the sound is designed with a low sound pressure level, pedestrians will not recognize the approach of vehicle due to background noise. To avoid nose pollution and permit the detectability of an approaching vehicle, a method for evaluating the annoyance and detectability of an electric vehicle is required. In this paper, the whine index evaluating the whine sound masked by the background was developed and used as a sound metric. This metric was employed for the development of an annoyance index and detectability index for electric vehicles.     

Evaluation of driver satisfaction of travel information on variable message signs using fuzzy aggregation

Driver satisfaction regarding travel information provided by variable message signs (VMS), which are part of the Nam‐Mountain Tunnel ATIS, was evaluated using fuzzy aggregation. Application of fuzzy aggregation to analyze driver satisfaction allows one to represent the variability and complexity of human perception with great fidelity. A fuzzy weighted average using two sets of fuzzy membership functions was applied to evaluate individual satisfactions of delay and travel time information provided. Then, those individual satisfactions were aggregated to estimate the driver group's overall satisfaction. The evaluated overall satisfaction was 0.65 for delay information and 0.63 for travel time information. Through these results, it was found that users of the travel information provided by the VMS in the Nam‐Mountain Tunnel ATIS were somewhat satisfied with the service quality. Those overall satisfactions were compared with a conventional weighted average and traffic operational effects to demonstrate the usefulness of the developed fuzzy method.     

Non-singular slip (NSS) method for longitudinal tire force calculations in a sudden braking simulation

In a dynamic vehicle simulation, longitudinal tire force is primarily based on the longitudinal slip (ratio). In the longitudinal slip formula, state variables are used in the denominator. This causes a divergence problem for numerical simulations of vehicle dynamics. To avoid this numerical singularity, a differential slip calculation method was developed for use in dynamic vehicle simulations. However, this method also causes a singularity when the wheel velocity approaches zero in a pure slip state, such as during sudden braking. In this paper, a new longitudinal slip calculation method, which can overcome singularities in all velocity conditions, is proposed. For this purpose, the Taylor series is adapted to the slip formula and the idea of virtual wheel rotation stiffness is introduced for the development of the slip equation. The physical phenomenon at the zero slip state is analyzed. Finally, the proposed slip formula is used to solve the numerical singularity problem, and the non-singular slip (NSS) calculation method is proposed. The proposed NSS method is applied to tire model performance test (TMPT) simulations to validate its performance.     

Torque ripple minimization control of permanent magnet synchronous motors for EPS applications

This paper identifies a control method used to reduce torque ripple of a permanent magnet synchronous motor (PMSM) for an electric power steering (EPS) system. NVH (Noise Vibration Harshness) is important for safe and convenient driving. Vibration caused by motor torque is a problem in column type EPS systems. Maintaining a very low torque ripple is one solution that allows for smoother steering. Theoretically, it is possible to design and drive the motor without torque ripple. However, in reality, a PMSM system torque ripple is caused by the motor itself (saturation in the iron core and EMF distortion) and the imperfect driver. This paper analyzes torque ripple of a PMSM system, and an advanced PMSM control method for the column typed EPS system is presented. Results of the analysis indicate that the compensation current is needed in order to minimize torque ripple when a PMSM is driven.