Evasive manoeuvres with a steering robot

In the pursuit of an objective rating on vehicle stability performance, it is always desirable to reduce disturbances and inconsistencies during experimental evaluations, especially the ones introduced by human drivers. This paper presents the development of a steering robot designed for closed-loop steering tasks during evasive manoeuvres. It describes the controller structure and discusses experimental results, in addition to simulation/vehicle model verifications and theoretical control analysis.     

Key criteria influencing the choice of Arctic shipping: a fuzzy analytic hierarchy process model

As Arctic sea ice shrinks due to global warming, the Northern Sea Route (NSR) and the Northwest Passage (NWP) offer a substantial reduction in shipping distance between Asia and the European and North American continents, respectively, when compared to conventional routes through the Suez and Panama Canals. However, Arctic shipping routes have many problems associated with their use. The main objective of this paper is to identify the key criteria that influence the decisions of shipping operators with respect to using Arctic shipping routes. A multi-criteria decision-making methodology, the Fuzzy Analytic Hierarchy Process, is applied to rank four potential categories of criteria (‘economic’, ‘technical’, ‘political’ and ‘safety’ factors) and their sub-criteria.

The results of the analysis suggest that, on aggregate, ‘economic’ is the most important category of influential factors, followed by ‘safety’, ‘technical’ and ‘political’ factors. The paper concludes, however, that the most influential specific sub-criteria relate to risks that lie mainly within the ‘safety’ and ‘political’ domains and that, especially in combination, these overwhelm the importance which is attached to ‘economic’ factors such as reduced fuel use. Finally, the implications of these findings for the future development of Arctic shipping are addressed at a strategic level.     

Dynamic Estimation of Road Bank Angle

Road bank angles have a direct influence on vehicle dynamics and lateral acceleration measurement. A vehicle stability control system that knows road bank angle has an advantageous capability in achieving desired control sensitivities for maneuvers on ice and snow, among all surfaces, while avoiding false/nuisance activation on a banked road. Since neither lateral velocity nor road bank angle are directly measurable in current vehicle systems due to economical reasons, the major challenge is to differentiate the bias induced by road bank disturbances from actual effect of vehicle lateral dynamics in current measurements. This paper proposes a method of road bank estimation and provides theoretical background for the decoupling effort of lateral dynamics and road disturbances involved in bank estimation.     

Review of Countermeasures against Beach Erosion on the Taiwanese Coast

Beach erosion is one of the most significant coastal preservation problems in the world. This study first briefly addresses the influences of human activity on beach erosion. The seriousness of beach erosion in Taiwan has received considerable attention since the 1960s, following rapid population growth and economic development in the coastal areas. Hard solutions of stabilized structures against beach erosion in Taiwan at that time are reviewed based on their effectiveness in protecting property and their ability to produce a landscape that harmonizes with the adjacent coastal environment. Soft coastal defense solutions implemented recently in coastal regions in Taiwan are introduced and their benefits are discussed. This study concludes that various methods designed to prevent wave- and current-induced beach erosion should be based on analyses of nearshore hydrodynamics, sediment transport, coastal processes, and physiographic features of beaches.     

Estimation of land vehicle roll and pitch angles

In this article, two kinematics-based observers are proposed to estimate the vehicle roll and pitch angles by using an inertial measurement unit. The observers are mathematically proven to be stable if the vehicle yaw rate is not zero. With a design variation of the observer gains, the estimated roll or pitch angle is shown to further asymptotically converge to the true value, eliminating possible errors caused by the biases of the acceleration signals. Simulation results show that accurate estimation of both pitch and roll angles can be achieved without the help of external sensors such as global positioning systems, either by using the accelerometer-based reference pitch or roll angle as the maneuver varies, or by using an observer with zero steady-state error property.     

Development of an auxiliary mode powertrain for hybrid electric scooter

This paper proposes a design and implementation of an auxiliary mode, hybrid electric scooter (HES) by means of more cost-effective way for improving scooter’s performance and efficiency. The HES is built in a parallel hybrid configuration with a 24V 370W auxiliary power electric motor, a 24V 20AH battery, and an electronically controlled fuel injection internal combustion engine (ICE) scooter. In contrast to hybrid electric vehicles (HEVs), the issues concerning cost, volume, and reliability are even more rigorous when developing hybrid electric scooters (HESs). Therefore, the drive topology and control strategy used in HEV cannot be applied to HES directly. In order to hasten the developing phase and achieve the parametric tune-up of the HES component, a dynamic simulation model for the HES is developed here. Because the powertrain system is complex and nonlinear in nature, the simulation model utilizes mathematical models in tandem with accumulated experimental data. The method about the mathematical model construction, analysis and simulation of the hybrid powertrain used in a scooter are fully described. The efficacy of the model was verified experimentally on a scooter chassis dynamometer and the performance of the proposed hybrid powertrain is studied using the developed model under a representative urban driving cycle. Finally, Simulation and experimental results confirm the feasibility and prosperity of the proposed hybrid HES and indicate that the designed hybrid system can improve the fuel consumption rate up to 15% compared with the original scooter.     

A Novel Method to Predict Traffic Features Based on Rolling Self-Structured Traffic Patterns

In this study, a novel method is proposed to predict the traffic features in a long freeway corridor with a number of time steps ahead. The proposed method, on the basis of rolling self-structured traffic patterns, utilizes the growing hierarchical self-organizing map model to partition the unlabeled traffic patterns into an appropriate number of clusters and then develops the genetic programming model for each cluster to predict its corresponding traffic features. For demonstration, the proposed method is tested against a 110-km freeway stretch, on which 48 time steps of 5-min traffic flows are predicted (i.e., a 4-h prediction). The prediction accuracy of the proposed method is compared with other models (ARIMA, SARIMA, and naive models) and the results support the superiority of the proposed method. Further analyses indicate that applications of the proposed method to larger scale freeway networks require sufficient lengths of observation to acquire enough traffic patterns for training and validation in order to achieve higher prediction accuracy.     

Can we really measure the impact of port governance reform?

Approaches by governments to reforming the way in which ports are governed are critical to how ports operate and fulfil their roles, and much research is devoted to investigating the impact of such reform. Yet, although the challenges of such research are noted, little attention is devoted to questioning whether measuring such impact is actually possible. We argue consideration of this question is fundamentally important for policy makers and researchers. Specifically, if uncertainty exists regarding whether we have measured the impact of the reform, how can we research its effect or justify its introduction? Conversely, a more conscious consideration of whether we can really measure the impact of port governance reform arguably means a more effective contextualization and rationalization of both policy and research. In this polemical paper, we critically consider three salient areas in relation to whether we can really measure the impact of port governance reform: ‘key terms and their ambiguity’, ‘aspects of time and geography’ and ‘issues of methods and context’. We summarize the key issues and offer suggestions for policy makers and researchers to approach them in an aim to both help measure the impact of port governance reform and also aid future policy development.     

Operational performance evaluation of major container ports in the Asia-Pacific region

If international container ports are to gain a proper appreciation of their various advantages, disadvantages and potential opportunities in a globally competitive environment, it is essential that they conduct effective evaluation of their operational performance. The present study applies five models of data envelopment analysis (DEA) to acquire a variety of complementary information about the operational efficiency of major container ports in the Asia-Pacific region and to identify trends in port efficiency. The study first establishes the causes of inefficiency on the basis of efficiency value analysis. Slack variable analysis is then used to identify potential areas of improvement for inefficient ports. This is followed by the utilization of return to scale analysis to assess whether each port is in a state of increasing, decreasing, or constant return to scale. Finally, a sensitivity analysis is conducted to identify which input or output variables have larger weights in terms of efficiency. The results provide valuable information for port managements in their attempts to establish competitive strategies for the future and to improve their resource utilization for ongoing improvements in operational efficiency.     

进口工程机械变矩器溢油原因分析

本文从结构和实例剖析、阐明了进口工程机械液力变矩器向外溢油的各种原因，并提出了防止措施。