Main Bus Research Articles

Impact of COVID-19 on perceived risk and mental health among public transport users in a medium-sized metropolitan area in Spain

BACKGROUND AND AIM: The COVID-19 pandemic has impacted the mental health of the population worldwide. However, little is known about the mental health impact on collectives such as health and essential workers or public transport users. Previous literature has shown how traveling in confined spaces with other people might lead to conditions of stress or anxiety. However, since most studies have focused on crime-related safety, more research is needed on the perceived risk of contagion and its association with transit users’ mental health. The aim of this study is, first, to evaluate the impact of the COVID-19 pandemic on anxiety and depression levels of public transport users and, second, to explore the influence of these conditions on the perception of public transport safety. METHODS: A random sample of public transport users (N=2,791) were surveyed at the main bus stations and stops in the main two cities of the Tarragona Metropolitan Region (Reus and Tarragona) between October 2020 and January 2021. RESULTS:Preliminary results show how the number of public transport users that frequently felt sadness in the past weeks increased by 6.8 percentual points after COVID-19’s outbreak (from 5.16% in 2019 to 12.0% in 2020), and those who frequently felt fear and anxiety increased by 13 points (from 5.8% in 2019 to18.8% in 2020). Regarding their perceived risk of contagion, public transport was the space where they felt a higher risk (5.5/10), in contrast with their home (1.6/10). Public transport vehicles were the spaces within a trip where participants felt a higher threat of contagion (5.6/10) in comparison with stops at the origin (3.8/10) and at the destination (3.6/10). CONCLUSIONS:Understanding the factors associated with the perception of virus-related safety such as COVID-19 is key for the retention of public transport users, which has become a major challenge for many cities around the world. KEYWORDS: Mental health outcomes, Socio-economic factors, Others: COVID-19

복원력 개선을 위한 공급지장 부하 판별법과 고장설비 복구 우선순위

This paper presents the criteria for determining recovery priority that can improve the post-event resilience. Through case studies, it is checked whether the existing recovery strategy, which considers recovered capacity or connection with the main bus, works well even in extreme disaster. This paper proposes a new strategy that considers not only the recovered capacity but also the time required for recovery as a recovery strategy that can improve resilience. In addition, this paper proposes a new method to identify interrupted customers after a disaster. The proposed method can calculate the amount of power interrupted simply without iterative calculation or modification of the matrix representing the power system structure. The resilience results of the recovery priority according to each strategy were compared for the three IEEE test feeders, from the N-2 to the N-5 contingency.

A Hybrid Wired/Wireless Deterministic Network for Smart Grid

With the rapid growth of time-critical applications in smart grid, robotics, autonomous vehicles, and industrial automation, demand for high reliability, low latency and strictly bounded jitter is sharply increasing. High-precision time synchronization communications, such as Time Triggered Ethernet (TTE), have been successfully developed for wired networks. However, the high cost of deploying additional equipment and extra wiring limits the scalability of these networks. Therefore, in this article, a hybrid wired/wireless high-precision time synchronization network based on a combination of high-speed TTE and 5G Ultra-Reliable and Low-Latency Communications (URLLC) is proposed. The main motivation is to comply with the low latency, low jitter, and high reliability requirements of time critical applications, such as smart grid synchrophasor communications. Therefore, in the proposed hybrid network architecture, a high-speed TTE is considered as the main bus (i.e., backbone network), whereas a Precision Time Protocol (PTP) aided 5G-URLLC-based wireless access is used as a sub-network. The main challenge is to achieve interoperability between the PTP aided URLLC and the TTE, while ensuring high precision timing and synchronization. The simulation results demonstrate the impact of the PTP-aided URLLC in maintaining network reliability, latency, and jitter in full coordination with the TTE-network.

Analysis of Internal Signal Perturbations in DC/DC and DC/AC Converters under Arc Fault

The constant increase in electrical energy consumption has led to a growth of photovoltaic installations (PV) along with the corresponding power converters for proper operation. Power electronics converters represent a challenge to maintain the system’s performance and safety; one such problem is series DC Arc Fault (AF). DC AFs lead to fire risk, damaging the main bus and the loads when not detected and interrupted in time. Therefore, research about DC AFs in power electronics converters must be carried out to predict the behavior and help avoid damage to the system. In this work, an innovative hybrid multilevel inverter for PV applications is used to explore the effect of series DC AFs in the converters’ internal signals, with the aims of setting the bases for the development of a detection system for power electronics. Both stages of conversion (DC/DC and DC/AC) are presented. In addition, the placement of the MPPT converter was considered for the tests. The AF experimental tests were performed with a generator based on the UL1699B specifications. The measurements of signals were performed in strategic points of the DC side, and changes and how to exploit them are discussed. This study contributes to a better understanding of the DC AF phenomenon and provides new insights for the development of new PV system protections.

3D-Position Determination using GNSS Techniques – A Comparative Analysis

This study was carried out to determine 3D-position of selected points within Obafemi Awolowo University. The points were located at Africa Regional Institute for Geospatial Information Science and Technology (AFRIGST), Central Technological and Laboratory Workshops (CTLW), main Bus Stop, Religion ground, New Environmental Design and Management (New EDM), and Spider building. China HuaCe Corporation (CHC) GPS and Promark 3 GPS were used to carry out observation on the selected points. The data gotten were post processed using GNSS solution software for Promark3, Compass software for CHC GPS and the result gotten were compared with the known coordinates of those points. The data was analyzed using Statistical Package for Social Sciences (SPSS) to determine the most accurate instrument between the two. The occupation time for the two instruments on each station was 45 minutes. Analysis of Variance (ANOVA) and Chi square Variance analysis were conducted, the result showed that there is no significant difference between the observations of the two instruments in comparison with the adjusted coordinate. It can be concluded that any of the two instruments can be used for 3D point positioning to obtain accurate result.

3D-Position Determination using GNSS Techniques – A Comparative Analysis

This study was carried out to determine 3D-position of selected points within Obafemi Awolowo University. The points were located at Africa Regional Institute for Geospatial Information Science and Technology (AFRIGST), Central Technological and Laboratory Workshops (CTLW), main Bus Stop, Religion ground, New Environmental Design and Management (New EDM), and Spider building. China HuaCe Corporation (CHC) GPS and Promark 3 GPS were used to carry out observation on the selected points. The data gotten were post processed using GNSS solution software for Promark3, Compass software for CHC GPS and the result gotten were compared with the known coordinates of those points. The data was analyzed using Statistical Package for Social Sciences (SPSS) to determine the most accurate instrument between the two. The occupation time for the two instruments on each station was 45 minutes. Analysis of Variance (ANOVA) and Chi square Variance analysis were conducted, the result showed that there is no significant difference between the observations of the two instruments in comparison with the adjusted coordinate. It can be concluded that any of the two instruments can be used for 3D point positioning to obtain accurate result.

Transient and steady-state faults location in intelligent distribution networks compensated with D-STATCOM using time-domain equations and distributed line model

Intelligent electric distribution networks compensated with D-STATCOM are active networks in which data of terminals is important for better distribution of energy. Similar to all electricity network devices, energy distribution lines in such networks are also subject to transient and steady-state AC faults, e.g., short circuit. Sections of the network in which the fault occurs are separated by relays. In such a condition, fault location and restoring the normal status of the network are important. Fault location in these networks is performed based on synchronous data of two terminals because data of all buses are transmitted to the main bus In this paper, a time-domain equation method (TDEM) is proposed for locating faults on smart distribution grid (SDG) using distributed line model based on time-domain equations. The proposed method locates the point of transient and steady-state fault in SDG considering DGs and compensators. In this paper, the D-STATCOM and wind power plant are considered in SDG. The suggested method does not need the D-STATCOM and DGs model for applying the algorithm. It only uses data of less than half of the cycle for executing the algorithm. The numerical simulation confirms that the proposed fault location method is accurate and it provides a reliable solution for automatic fault location problem in distribution networks.

Association of Infrastructure and Route Environment Factors with Cycling Injury Risk at Intersection and Non-Intersection Locations: A Case-Crossover Study of Britain.

Objective: This paper examines infrastructural and route environment correlates of cycling injury risk in Britain for commuters riding in the morning peak. Methods: The study uses a case-crossover design which controls for exposure. Control sites from modelled cyclist routes (matched on intersection status) were compared with sites where cyclists were injured. Conditional logistic regression for matched case–control groups was used to compare characteristics of control and injury sites. Results: High streets (defined by clustering of retail premises) raised injury odds by 32%. Main (Class A or primary) roads were riskier than other road types, with injury odds twice that for residential roads. Wider roads, and those with lower gradients increased injury odds. Guard railing raised injury odds by 18%, and petrol stations or car parks by 43%. Bus lanes raised injury odds by 84%. As in other studies, there was a ‘safety in numbers’ effect from more cyclists. Contrary to other analysis, including two recent studies in London, we did not find a protective effect from cycle infrastructure and the presence of painted cycle lanes raised injury odds by 54%. At intersections, both standard and mini roundabouts were associated with injury odds several times higher than other intersections. Presence of traffic signals, with or without an Advanced Stop Line (‘bike box’), had no impact on injury odds. For a cyclist on a main road, intersections with minor roads were riskier than intersections with other main roads. Conclusions: Typical cycling environments in Britain put cyclists at risk, and infrastructure must be improved, particularly on busy main roads, high streets, and bus routes.

Evaluation of Incorporation of Universal Design Parameters in the Planning Approval Process of Kisumu Main Bus Terminus

Consideration of the normate template by designers usually leads to the production of living spaces that fail to meet most of the spatial requirements of would-be users. This phenomenon arises due to the fact that the normate template keeps a walking and fleshy body at the centre of thinking about design. As a result, the template fails to consider additional space requirements for bodies that use technologies to navigate space. In order to sustain itself, the normate template relies upon the impression that normates are normal, average, and majority bodies. When built-up spaces block out potential users, then the viewpoint which is reinforced is that certain spaces are meant only for those who are “privileged” to use these spaces independently. The presence of accessible spaces on the other hand confirms that designers hold that built environments should serve all potential users regardless of physical stature. Universal Design thereby provides a platform for making the weakest person in society strong through design. Embracement of a Universal Design perspective therefore becomes a stepping stone in the provision of public spaces that are accessible to all- regardless of physical stature. This study, therefore, evaluated the incorporation of Universal Design parameters in the design process of public spaces in Kisumu City. The study established that Universal Design requirements are usually executed only on new constructions. There is a need, therefore for major renovations to take place in buildings open to the public that are not necessarily classified as “new” constructions.

Analysis Of Customer Satisfaction On The Application Of The Covid-19 Protocol At The Inter-City Bus Terminal

The rise of the Covid-19 outbreak in Indonesia, especially Bekasi City, it is very strong influencing the existing regulations at the Bekasi city main terminal the author wants to research customer satisfaction with the facilities and implementation of the Covid-19 protocol at terminal bus in Bekasi City. This study aims to describe the perception of satisfaction customers using a questionnaire against health protocols in terminal facilities in the terminal main bus Bekasi. This method is carried out by direct survey to the location research in order to obtain data on existing facilities. Then also with distributed questionnaires to 90 respondent. The population taken in the study these are customers at the Bekasi City Main Terminal. The data processed in this study uses Microsoft Excel and SPSS versions 24 and 16 with method used by Importance Performance Analysis (IPA). It was found that the performance level facilities and customer satisfaction that must be considered in A Quadrant. The main priority is for smoking prohibition, drainage, special access pedestrians / passengers with special needs, luggage storage, charging station, and the facilities for a nursing room.

Sensorless Control of DC Microgrid Based on Artificial Intelligence

Nowadays, DC microgrids are preferred in the field of renewable energy. The autonomous DC microgrids aim to provide smooth power flow from renewables to loads. While satisfying certain load profiles and sustaining the power as the desired level, the control of power converters is considerable. To ascend the resilience of DC microgrids, battery storage systems (BSSs) are also used as a backup unit for supplying uninterrupted power. The main task of BSSs is to compensate for the lack of power when the load is higher than supplied power or store the surplus of power in case that the load demand is less than the extracted power. In other words, by draining and storing the power, BSSs help to increase the flexibility of the system and keep the main DC bus voltage within acceptable bounds. This study introduces artificial intelligence (AI)-based method to diminish the number of implemented sensors and control power converters without reducing efficiency. In this paper, artificial neural networks (ANNs) as a subset of AI are exploited. Diminishing the number of sensors in the control layer makes the system more reliable. To validate the effectiveness of the proposed system, phases of ANNs' simulations are performed in MATLAB/Simulink.

Smart protection system for identification and localisation of faults in multi‐terminal DC microgrid

DC microgrid provides the horizontal infrastructures to integrate distributed generation (DG) and loads. Unlike traditional AC systems, DC systems cannot survive or sustain high magnitude fault currents. It makes locating faults very difficult. The conventional protection techniques completely de-energies the DC link in the DC microgrid. A new protection scheme for multi-terminal DC microgrid against line-to-line fault and the low resistance earth fault is presented in this study. The scheme isolates the faulted section from the DC microgrid. Healthy sections are operated without any disturbance and supply continuity is maintained in a ring main DC bus system. The current sensors are mounted at DC bus segments to monitor the entering and outgoing current at different nodes. Further, the current sensors are also mounted at both ends of service mains to monitor their current difference at both ends of the service mains. The controller detects this current difference and opens circuit breakers. To meet the requirement of fast interrupting time and high short-circuit current withstanding capability, insulated-gate bipolar transistors used as circuit breakers. The fault location scheme gives the fault location in various sections (service mains) and faults resistance in the microgrid. The proposed concepts have been verified by computer simulation.

Integrating underground line design with existing public transportation systems to increase transit network connectivity: Case study in Greater Cairo

Connectivity is a significant problem in large-scale transit networks because the number of transfers required to conduct a trip is considered a discomfort by transit users. This paper presents a practical solution for an underground metro line planning problem by integrating existing bus and metro networks into a single connected transit network. The proposed method aims to obviate the usual combinatorial complexity when solving a transit route design problem. It aims to increase the overall transit system connectivity by selecting a consistent and non-demand-oriented criterion for the design. The metro lines are designed by minimizing passenger transfers through the transit network according to predefined demand node pairs. The design scheme offers a set of ring route alternatives for a sizeable case study in Greater Cairo. The case study selected sixteen traffic analysis zones, an existing metro network consisting of three main lines (113.6 km long), and twelve main bus lines (487.7 km long) for analysis. TransCAD software was used as the basis for coordinating the stations and lines of both the bus and metro systems. Subsequently, a passenger transfer counting algorithm was implemented to determine the number of transfers required between stations from each origin to each destination. A passenger origin–destination transfer matrix was created using the NetBeans integrated development environment to help determine the number of transfers required to complete trips on the transit network before and after proposing the new line. Based on the evaluation, the ring lines were highly efficient at significantly decreasing passenger transfers between stations with the minimum construction cost. This study will be of value during the strategic stages of the transit line design and will assist in rapidly generating initial solutions when certain demand information is unavailable.

Travel Time Reliability of Bus Operation in Heterogeneous Traffic Conditions of Dar es Salaam City, Tanzania

Abstract The assessment of travel time reliability enables precise prediction of travel times, better activity scheduling and decisions for all users of the road network. Furthermore, it helps to monitor traffic flow as a crucial strategy for reducing traffic congestion and ensuring high-quality service in urban roads. Travel time reliability is a useful reference tool for evaluating transport service quality, operating costs and system efficiency. However, many analyses of travel time reliability do not provide true travel variation under heterogeneous traffic flow conditions where traffic flow is a mixture of motorized and non-motorized transport. This study analysed travel time reliability under heterogeneous traffic conditions. The travel reliabilities focused on passenger waiting time at bus stops, in-vehicle travel time, and delay time at intersections which were analysed using buffer time, standard deviation, coefficient of variation, and planning time. The data used were obtained from five main bus routes in Dar es Salaam. The results indicate low service reliability in the outbound directions compared to inbound directions. They also intend to raise awareness of policy-makers about the situation and to make them shift from expanding road networks towards optimising road operations.

Energy drink: the consumption prevalence, and awareness of its potential health implications among commercial drivers in the Ho municipality of Ghana

BackgroundConsumption of energy drinks has become an escalating global public health problem. The work schedule and irregular sleeping habits of commercial bus drivers make them highly susceptible to getting fatigued, hence most of them consume energy drinks as a fatigue management strategy. However, consumption of energy drinks produces numerous psychomotor side effects that if consumed among drivers puts the traveling public in danger of road accidents. This study sought to assess the prevalence of energy drink consumption and awareness of associated potential health problems among commercial long-distance bus drivers operating from the Ho municipality.MethodsThe study population comprised about 266 commercial bus drivers. This was a cross-sectional study involving 132 participants who completed a structured questionnaire on the participants’ socio-demographic characteristics, frequency of consumption and reasons for consumption. It also included questions to assess the knowledge of the ingredients and side effects of energy drinks. Respondents were selected using a convenience sampling technique. Descriptive analysis and Chi-square test of association were used to analyse the data.ResultsA majority (62.1%) of the drivers had more than 10 years of commercial driving experience. A 75% energy drink consumption prevalence was recorded with driving performance enhancement (78.8%) as the predominant reason for consumption. 7–10 bottles per week were consumed by most (32.2%) of the drivers. Also, 72.0% had poor knowledge of the side effects linked with energy drink consumption as well as the ingredients for preparation.ConclusionEnergy drinks were consumed by the majority of the drivers at the Ho main bus terminal of which most of the drivers had poor knowledge of the potential health problems linked with the consumption of these drinks. The consumption of energy drinks was observed to be higher among the drivers with lower education levels, higher monthly income and those who worked long hours in a day. The Ghana National Road Safety Commission (GNRC) in collaboration with other private road transport unions in Ghana should organize regular seminars for commercial bus drivers on the potential dangers and effects associated with energy drink consumption.

Formula omitted] based control of a DC/DC buck converter feeding a constant power load in uncertain DC microgrid system

DC microgrids are gaining more and more popularity and are becoming a more viable alternative to AC microgrids (MGs) due to their advantages in terms of simpler power converter stages, flexible control algorithms and the absence of synchronization and reactive power. However, DC-MGs are prone to instability issues associated with the presence of nonlinear loads such as constant power loads (CPL) known by their incremental negative impedance (INI), which may lead to voltage collapse of the main DC Bus. In this paper, H∞-based controller of a source side buck converter is designed to avoid the instability issues caused by the load-side converter acting as a CPL. Besides, the proposed controller allows a perfect rejection of all perturbations that may arise from parameter variations, input voltage and CPL current fluctuations. The design process of H∞-based controller is based on the Golver Doyle Optimization Algorithm (GDOA), which requires an augmented system extracted from the small-signal model of the DC/DC converter including the mathematical model of parameter variations and overall external perturbations. The​ H∞ based controller involves the use of weight functions in order to get the desired performances. The proposed controller is easy to implement and lead to reducing the implementation cost and avoid the use of current measurement that may have some disadvantages. The derived controller is validated by simulation performed in Psim software and experimental setup.

Multidrop Transmission System Based on Reflection-Canceling Scheme With Reflection Compensation Lines

In the digital communication system, waveform distortion due to reflection of the multidrop transmission line is one of the main issues for high-speed signal transmission. Although many approaches to reducing the reflection, such as asymmetrical power splitter, stub series terminated logic, and the segmental transmission line have been used in the past, the drawbacks of amplitude loss at the receivers, or high power consumption due to excessively low impedance design are still problems. In this article, we introduce a new method, “reflection compensation line (RCL),” which is constructed in isometric length of main bus segments and stub lines. The method using the RCL intentionally generates reflections to cancel the distortion and restore the ideal waveform at the receivers. In order to reduce the waveform distortion effectively, an optimal set of transmission parameters is determined by means of evolutionary gradient search. The performance of the proposed method especially at the stub lines of both ends of the main bus line is confirmed using the SPICE simulation, and its applicability to practical systems is also discussed.

Simultaneous reactive power sharing and voltage regulation in an autonomous networked microgrid

Decentralised droop-like control method is the most favourable control system for power converter-based microgrids (MGs). In conventional V - Q droop loops, reactive power sharing is used as a means of voltage regulation to prevent currents from circulating among distributed generation units. However, since the voltage is not a global variable, reactive power sharing is not implemented precisely, and thus converters may be exposed to overcurrent conditions and the stability of the MGs is put at risk. Besides, the droop-like reactive power sharing causes voltage deviations and power quality issues. This study proposes a novel control method which is able to implement accurate reactive power sharing and voltage regulation to its nominal band in a networked MG. Both the control targets are achieved, fast and simultaneously, by only one control signal. So the requirement of a secondary controller for voltage restoration is obviated. A novel power flow-based method is proposed to estimate the voltage at the MG main bus, which is adopted as a common variable, thus making the proposed method decentralised. The presented method is fast, effective and applicable to networked MGs with arbitrary topology. Simulation results prove the effectiveness and superiority of the proposed method over existing methods.

Model and Solution Methods for the Mixed-Fleet Multi-Terminal Bus Scheduling Problem

Public transport services are currently executing or planning a fundamental transition from traditional buses to electric buses. During this transition phase, the public transport offering is fulfilled with a mixed fleet across multiple bus terminals, which poses operational challenges for optimal vehicle scheduling, a problem not yet addressed in literature. As researchers in Transport Engineering and Operational Research at the University of Luxembourg, in collaboration with the Roma Tre University, we support the Ministry of Transport of Luxembourg and Volvo buses by modelling and simulating this transition phase, to help them managing and solving such challenges. In this work we develop a mixed-integer linear programming (MILP) formulation of the problem and implement a time-based decomposition framework, through which we can optimize real-life daily instances. This method is tested on the main urban bus lines that connect Central Station, Luxembourg Airport and ten other major terminals within Luxembourg City, providing (near) optimal solutions that explicitly consider the energy constraints arising from electric bus operations, while establishing an advantageous trade-off between delaying trips, to implement quick-charging of electric buses, and performing the same trip with costlier traditional buses. The results show a consistent decrease of operational costs as the percentage of e-buses in the fleet increases.

Modelling and Control of Modular DC-Nanogrids Based on Loss-Free Resistors

This paper proposes a modular photovoltaic (PV) dc-Nanogrid (dc-NG) architecture for residential applications. The proposed architecture is based on the Loss-Free Resistor (LFR) concept. The dc distribution bus is supplied by PV panels, ac utility and a storage battery. The storage battery is connected to the main dc bus through a dc-dc bidirectional converter (BDC). This battery has also an important role to ensure uninterruptible power supply to the critical loads and controls the power flow in the dc-NG. A mathematical model of the system is first derived and a stability analysis is carried out showing that the stability is guaranteed under certain mild conditions. Numerical simulations of a case study for two PV panels corroborate the theoretical predictions which have been finally confirmed by experimental measurements.