Trang: 344-358 Hoang Thuy Linh, Nguyen Thi Hong Hanh, Phan Thi Thu Hien, Nguyen Hoang TungTóm tắtProviding equal accessibility to social activities and transport to everyone is an important task of the transport authorities, especially in developing countries. However, the transport planners mainly focus on expanding the network coverage but lack attention on the accessibility to the service for the aged people. In this study, we have investigated the preferences of different accessibility indicators from the perspective of the aged people in developing countries using the Analytical Hierarchy Process (AHP) technique. The importance level obtained from the popular rating via the Likert scale will also be compared with the AHP results. The findings presented in this work contributed more insights on the preferences of the aged people on accessibility to public transport, subsequently, better inform transport planners to improve the bus services in these countries. The comparison between self-report surveys via rating and preferences would be a reference for the consideration of survey tools in similar studies.
Longitudinal strain analysis in asphalt pavement under full-scale moving loads
Trang: 359-370 Le Xuan Quy, Nguyen Mai Lan, Nguyen Quang Tuan, Hornych PierreTóm tắtT The roadway networks have been played a vital role in the development of all countries. The assessments of pavement conditions during their service life are therefore decisive to maintain the stable performance of the network. From this point of view, pavement instrumentation allows monitoring pavement conditions continuously and without traffic interruption. The study aims to illustrate the effectiveness of embedded strain gauges and temperature probes to follow the pavement responses with different traffic speeds, traffic loads and temperature conditions. The longitudinal strain signals are then examined with regards to representative parameters of the loading times and strain amplitude. The results show that the traffic load levels and asphalt temperature are directly responsible for the change of strain amplitudes, while those have almost no impact on loading times. Numerical simulations are also introduced to validate the applicability of both layered elastic and viscoelastic models to the strain signals observed in the field.
Performance evaluation of Korean modified asphalt binder under Vietnam conditions
Trang: 371-380 Van Phuc LeTóm tắtIn recent years, study on asphalt binder that provide strong rutting and cracking resistance is considered of great significance as it can help provide extended pavement life and significant cost savings in pavement construction in Vietnam. The purpose of this paper is to evaluate the performance characteristics of Korean modified asphalt binder in hot mix asphalt (HMA) mixture under Vietnam condition. To accomplish this objective, the mechanical properties of Korean modified binder in AC mixtures were evaluated using tests such as the Marshall stability and flow, indirect tensile (IDT), moisture resistance, and Wheel Tracking. It was found that the Korean modified binder can improve significantly not only the rutting performance but also the moisture damaged resistance of asphalt pavement. Furthermore, the performance life of Korean modified binder for AC mixtures was evaluated through the mechanistic- empirical pavement design guide (MEPDG) program. Based on the results of the study, it can be concluded that the Korean modified asphalt binder can enhance the performance of asphalt mixtures significantly under Vietnam conditions.
A fuzzy-based methodology for anticipating trend of incident traffic congestion on expressways
Trang: 381-396 Trinh Dinh ToanTóm tắtTraffic control decisions for incident congestion management on expressways are often made in the face of uncertainty because it entails using many forms of both current and predicted traffic data and incident information to arrive at control decisions under critical-time pressure. For these reasons, an effective traffic control strategy during incidents often relies on techniques that deal efficiently with problems of uncertainty and imprecision. Motivated by this, the author has carried out a research project that develops a multi-stage Fuzzy Logic Controller (MS-FLC) as a tool to support traffic operator’s decision-making at the operational level. The research project aims at establishing a systematic procedure in deriving control actions for ramp control during incidents on expressways following fuzzy-logic approach. For proactive ramp control, the trend of traffic condition on expressways during incidents should be properly anticipated. This paper presents the first two stages of the MS-FLC: (1) evaluation of traffic condition upon incident occurrences, and (2) anticipation of traffic condition during incidents. The results show that the MS-FLC provides a systematic procedure in deriving control actions using fuzzy-based methodology, which possesses excellent capabilities in data-handling and knowledge representation to deliver linguistic expressions that is easy to understand by the operators for making decisions. With both current and anticipated types of information obtained from these two stages, the MS-FLC operates on both reactive and proactive control manners so as to enhance performance of the incident management on expressways.
An applied grey wolf optimizer for scheduling construction projects
Trang: 397-411 Trinh Thi Trang, Nguyen Luong HaiTóm tắtConstruction project delay has been reported as a significant cause of the project’s failure, which results in cost overrun, thereby decreasing the effectiveness of the project. Therefore, project management has placed much effort in construction works’ scheduling to enhance project performance. However, construction schedule has been commonly addressed within traditional methods that rely on project managers’ subjective experiences and manually-performed approaches, resulting in time-consuming and inaccurate decision-making. This study is thus aimed to handle these limitations. Using analyses of the Grey Wolf Optimizer (GWO) model, inspired by the leadership hierarchy and hunting mechanism of grey wolves in nature, this study supports reducing the construction time and minimizing the additional construction cost. Furthermore, another computational tool, namely Solver-addins, is also used to verify the reliability of the result. The findings of this study will provide a valuable tool for supporting construction management to deliver projects on time, improving construction project performance
A study on the determination of the real-world driving characteristics of motorcycles in Hanoi
Trang: 412-426 Nguyen Thi Yen Lien, Nguyen Duc Khanh, Cao Minh Quy, Than Thi Hai Yen, Bui Le Hong MinhTóm tắtThe transport sector has been considered as one of the primary reasons of the situation of rapid climate change. This paper aims to determine the real-world driving characteristics of motorcycles (MCs) in Hanoi to support further studies on MCs' emissions and fuel consumption. An infrared sensor was installed directly on the wheel of the test MC to record the revolving speed of the wheel. After that, the instantaneous speed of the test MC was calculated and pre-processed. Only about 0.82% of total data points were detected as error points and processed. Twenty-five driving kinetic parameters were calculated based on the processed instantaneous speed data to reflect the real-world driving characteristics of MCs in Hanoi. The change in the real-world driving characteristics of MCs in Hanoi from 2009 to 2020 has been recognized, particularly the share of the time proportion in different operation modes. The time proportion of the acceleration, deceleration, cruising, creeping, and idling modes in the real-world driving characteristics of MCs in Hanoi is 35.51%, 34.52%, 11.23%, 12.01%, and 7.13%, respectively. The average speed of MCs in Hanoi is about 20.49 kph. The VSP distribution in the real-world driving data of MCs in Hanoi is concentrated mainly at the bins relating to idling and low speeds.
Trang: 427-438 Nhu Quynh Luc, Thi Nga Tran, Cong Khanh Ngo, Huy Duc Tran, Van Chien Nguyen, Tien Anh TranTóm tắtAn embedded device is becoming popular in daily life thanks to their low power consumption and multiprocessing capability. In particular, the security of embedded devices has been a big issue of concern to academic and industrial communities. This study aims at the Grain 128-AEAD authenticated encryption with associated data algorithm embedded on low-power and resource-constrained devices. This stream cipher belongs to the Grain family developed from the Grain-128a algorithm, and it has the advantage of not only providing security, but also adding authenticity to the associated data to ensure the authenticity, integrity and confidentiality of the data. It is also considered suitable for IoT (Internet of Thing) platforms and embedded device applications with limited resources and low power consumption. In this study, the algorithm was implemented on STM32 processor family. The resulting code size is only 832 bytes, and the total execution time for a 128-byte input block of Grain-128AEAD algorithm (Encryption and Decryption) takes 30 µs, which is better than previous implementations on various hardware platforms. The compiled file size is only 54kB, which makes the algorithm fit embedded applications.
A review of bus crash severity analyses
Trang: 439-448 Thanh Chuong Nguyen, Minh Hieu NguyenTóm tắtThe bus plays an important role in serving the urban travel demand in both developed and developing countries. Unfortunately, the heavy operation of this mode may come together with crashes, which may cause adverse effects on its image and service quality from the view of the public, thereby leading to a reduction in ridership. The knowledge on characteristics of crashes is, therefore, desired. While most of the research focus is on the probability of crash occurrence, the severity of crashes has recently attracted increasing attention from researchers. This paper aims to synthesize previous studies on crash severity. By means of looking at 11 studies carefully selected from the SCOPUS database, this paper has provided a detailed synthesis of data collection, research areas, used samples, seven factor groups associated with the crash severity (Temporal characteristics, Location and infrastructure characteristics, Service and vehicle characteristics, Traffic characteristics, Crash characteristics, Weather characteristics, Driver characteristics and behaviours), and analytical methods. Afterwards, research gaps and shortcomings of the existing research are highlighted for proposing future research directions. This review could help to save efforts to obtain a clear understanding of bus crash severity. It may be an informative reference for those newly accessing the field of bus crash severity and/or intending to develop solutions to this problem.
