Station Access Research Articles

Assessing the Spatial Implications of Autonomous Vehicles as Feeders to Railway Stations in Suburban Melbourne

ABSTRACT Using results from a design-research studio analysing rail station access in Melbourne, this article considers how differing Autonomous Vehicle (AV) deployment models might fit into a suburban landscape. The results challenge assumptions about AV deployment. If AVs are low occupancy, peak demands may require station carparks to be used entirely as pick-up/drop off zones. This suggests little opportunity to re-purpose car parks for non-transport uses. Further, with AVs uncoupling station demand from existing feeder bus and park-and-ride provision, a re-distribution of demand along rail corridors may occur. The work has broad applicability to the policy challenges of an AV future.

MU-MIMO enabled uplink OFDMA MAC protocol in dense IEEE 802.11ax WLANs

IEEE 802.11ax supports orthogonal frequency division multiple access (OFDMA) for uplink (UL) transmissions where stations (STAs) access randomly chosen resource units (RUs) in a distributed manner. Nevertheless, as the number of STAs increases, frequent collisions can occur, which lead to throughput degradation in UL transmissions. To address this problem, we propose a multi-user multiple-input multiple-output (MU-MIMO) enabled UL OFDMA random access (MORA) protocol. MORA combines the ideas of OFDMA and MU-MIMO, and thus more than one STA can share the same RU, which can significantly reduce the collision probability in congested situations. Analytical and simulation results demonstrate that MORA improves the throughput of the standard OFDMA-only protocol significantly.

What Makes the Gears Go ‘Round? Factors Influencing Bicycling to Suburban Regional Rail Stations

In North America, most suburban commuters who use rail transit drive and park at stations, offsetting some benefits of commuter rail. Using passenger survey data collected at three rail stations near Toronto, Canada, we explored the correlates of bicycling for station access trips in a suburban context. Other than automobile ownership, no socio-demographic characteristics were associated with the likelihood of bicycling. Frequency of bicycling for transportation and recreation, preference toward sustainable, and active transportation, and weather-related comfort were correlated with bicycling to a station. Street density along shortest travel route and having to cross a major highway were barriers to bicycling.

Synchronous Teledermoscopy in Military Treatment Facilities.

Sustained demand for dermatologic care throughout military medicine, in conjunction with increasing dermatologic provider shortages, has led to increase use of teledermatology in military treatment facilities (MTFs). Initially used to aid in the differentiation of suspicious melanocytic lesions, dermoscopy has found increasing clinical utility in an expanding realm of general dermatologic conditions. We demonstrate the use of synchronous teledermoscopy within a remote MTF by repurposing webcam technology already available at most MTFs. Two patients were seen in clinic at a remote naval primary care clinic with limited subspecialties. Once written consent was retrieved, an on-site dermatologist evaluated each patient and performed a history and skin exam with dermoscopy. Synchronous consultations were conducted with the Global Med Cart (GlobalMed(R) Clinical Access Station with TotalExam(R) 3 HDUSB camera), and Cisco webcam video jabber (Cisco TelePresence PrecisionHD USB Camera part number TTC8-03). The patients then underwent individual synchronous teledermatology consultations with an off-site U.S. Navy dermatologist located in the continental United States. The methodology for the consultation involved the use of a standard dermatoscope and jabber webcam. Two synchronous teledermatology consultations were completed successfully on patients in MTFs with limited subspecialty capabilities. Both cases, with two lesions of concern per case, had 100% concordance between the on-site and teleconsulted dermatologist. Through observing inter-rater agreements between the on-site and remote dermatologists, this small study demonstrates a novel application of technology readily available at most MTFs.

The role of charging and refuelling infrastructure in supporting zero-emission vehicle sales

Widespread uptake of battery electric, plug-in hybrid, and hydrogen fuel-cell vehicles (collectively zero-emissions vehicles or ZEVs) could help many regions achieve deep greenhouse gas mitigation goals. Using the case of Canada, this study investigates the extent to which increasing ZEV charging and refuelling availability may boost ZEV sales relative to other ZEV-supportive policies. We adapt a version of the Respondent-based Preferences and Constraints (REPAC) model using 2017 survey data from 1884 Canadian new vehicle-buyers to simulate the sales impacts of increasing electric vehicle charging access at home, work, public destinations, and on highways, as well as increasing hydrogen refuelling station access. REPAC is built from a stated preference choice model and represents constraints in supply and consumer awareness, as well as dynamics in ZEV policy out to 2030. Results suggest that new ZEV market share from 2020 to 2030 does not substantially benefit from increased infrastructure. Even when electric charging and hydrogen refuelling access are simulated to reach “universally” available levels by 2030, ZEV sales do not rise by more than 1.5 percentage points above the baseline trajectory. On the other hand, REPAC simulates ZEV market share rising as high as 30% by 2030 with strong ZEV-supportive policies, even without the addition of charging or refuelling infrastructure. These findings stem from low consumer valuation of infrastructure found in the stated preference model. Results suggest that achieving ambitious ZEV sale targets requires a comprehensive suite of policies beyond a focus on charging and refueling infrastructure.

Modeling railway station access mode choice behaviour and rail travel demand

Modeling railway station access mode choice behaviour and rail travel demand

Unravelling the impact of street network structure and gated community layout in development-oriented transit design

We investigate the associations between walking patterns and street network structure in the context of transit station development intended to create its own demand rather than serve existing demand, and an urban morphology dominated by gated communities in station areas. We record the complete actual walking routes of 3637 metro users from station exits to their destinations. We then extract pedestrian access behaviour from these routes, summarised by link use density measured by pedestrian volume on each road segment; and route detour measured by deviation from the shortest access path. We unravel the impact of two design elements in station areas on the observed pedestrian access behaviours: street network structure measured by network centralities; and gated community layout measured by the degree of gatedness, numbers, and geographic size. The route detours and network centralities are calculated based on a complete pedestrian network that includes pedestrian paths inside the gated communities. The results show that network structure significantly impacts link use density. The higher the betweenness of a link (a network measure of connectivity to shortest paths), the higher the volume of metro riders using it. The main reason for pedestrians leaving metro stations on routes that deviate from the shortest access path was the presence of gated communities. The results suggest that in countries like China where metro station development is used as a land development and urban expansion strategy and where gated neighbourhoods are a common development typology, a policy to selectively open up gated communities to more permeable pedestrian flows would be in the interest of station access with attendant benefits, by deduction, such as promoting metro ridership and increasing population health. The research framework and key findings of this study are transferable to transit developments throughout China and in similar developing contexts.

GSMAC: Group-Scheduled MAC Protocol with Energy Beamforming in M2M Networks

In Machine-to-Machine (M2M) networks, an enormous number of stations with low energy budgets contend for the channel access in order to get the transmission opportunity, leading to huge amount of congestion. Energy beamforming technology enables wireless devices to replenish their energy much faster than the traditional energy harvesting strategies. In this paper, a group-scheduled Medium Access Control (GSMAC) protocol is proposed as a solution of managing the access of stations that transmit bursts of data packets while taking into account the benefit of energy beamforming technology in M2M networks. In the proposed protocol, nodes are grouped by multiple Power Beacons in order to reduce the high collision probability. Nodes first contend the channel access in each group for reservation opportunities so that the reserved nodes can transmit data and harvest energy simultaneously by Access Point scheduling the data and energy transfer order. Simulation and analytical results show that GSMAC has significant improvements compared with the traditional distributed coordination function in terms of saturation throughput, delay, and energy-related performances.

Spatio-temporal variation in some environmental variables of Bosso Dam, Nigeria

Bosso dam was constructed primarily for the Niger River basin municipal supply of drinking water and for other domestic use. Physico-chemical properties of Bosso Dam, Bosso, Niger state Nigeria were investigated monthly between September, 2015 and February, 2016 to determine seasonal variation, as well as providing a baseline data for monitoring water quality changes prompted by human induced factors. Water samples were collected from three accessible stations of the dam for chemical analyses using standard methods. One – way ANOVA were used to evaluate relationships between environmental variables with PAST. Findings on the physico-chemical status of the water revealed that temperature ranged from 27.0oC-30.5oC, weak acidic to weak alkaline pH range of 6.7-7.3, Dissolved Oxygen Concentration (5.0-8.0mg/l) was marginally high while the BOD range of (2.0-5.0mg/l) was relatively high. The essential primary productivity nutrients, Nitrogen (0.12-0.19mg/l), Phosphate (0.02-0.09mg/l) and Sulphate (9.3-17.7mg/l) were relatively low in all the sampled stations. The lake is not eutrophic, so, various management strategies such as periodic monitoring of physico-chemical parameters should be carried out and hence the need for an effective anthropogenic inputs control programme in the dam. The study further revealed that the dam could be used for irrigation purposes for dry season farming, health wise; the water should undergo a little treatment before consumption even though the dam was constructed purposely for the supply of drinking water to the people of Bosso and the environs.Keywords: physico-chemical, seasonal variation, Bosso Dam

Probability-based opportunity dynamic adaptation (PODA) of contention window for home M2M networks

With the emergence of the Internet of Things (IoT), the growing use of autonomous sensing and actuating devices in areas such as smart grid, e-healthcare, home networking, and machine-to-machine (M2M) communication has become an important communication paradigm. Nonetheless, to fully exploit the applications facilitated by M2M communication, service requirements such as data throughput, scalability and reliability must be in place. This paper proposes a new backoff adaptation mechanism known as probability-based opportunity dynamic adaptation (PODA) for M2M communication using the IEEE 802.11ah protocol. The proposed PODA is an enhanced version of the binary exponential backoff (BEB) where a station estimates the number of contending stations in a distributed manner and adaptively tunes its minimum contention window (CW) prior to the contention process for better network throughput and packet delivery ratio. Owing to its great flexibility and ease of implementation, BEB has been extended to home M2M communication such as wireless sensor networks and smart grid technologies without relying on wide area communication. However, the current form of BEB has its shortcomings in the emerging M2M paradigm. The adaptation of CW in PODA is based on the optimal station's access opportunity to improve network performance instead of direct CW scaling. Using the proposed adaptation method, the network throughput can be improved by as much as 18 percent in the home M2M network studied, while enhancing network reliability and fairness.

투표소 접근의 형평성과 효율성 향상을 위한 공간 최적화 모형

투표소 접근의 형평성과 효율성 향상을 위한 공간 최적화 모형

LS-Solar-PV System Impact on Line Protection

Large-scale photovoltaic power station access to the grid will profoundly change the fault current characteristics of the power station’s outgoing lines. This change results in adaptive problems in traditional protection phase selection components, which may cause incorrect actions in reclosing, protection ranging, and distance protection. Based on the fault current characteristics of the large-scale photovoltaic power station transmission line, this paper analyzes the adaptability of the phase current difference mutation and the sequence component phase selection component in protecting the Photovoltaic (PV) power plant side of the transmission line. Based on the fault current analytical formula, the phase relationship between the phase current difference and the current sequence component under different control targets, such as suppressing negative sequence current, suppressing the active power fluctuation, and suppressing the reactive power fluctuation, is derived. The operational performances of the phase–phase current difference of the abrupt phase selection component and the sequence component phase selection component of the power station side are degraded, which may cause incorrect operation of the phase selection component. Based on the actual engineering parameters of a PV power plant, a simulation model was built in Power System Computer Aided Design (PSCAD) to verify the correctness of the theoretical analysis.

The role of station accessibility, multimodal competitions and contextual variables in retaining customer base of urban commuter rails

The topic of transit loyalty has been marginalized in transportation literature. Nevertheless, in recent years, an interest in understanding the factors that affect transit loyalty has developed. This paper uses data from a passenger survey conducted by GO rail – the Greater Toronto and Hamilton Area regional rail service – to investigate the factors that influence transit user loyalty. In addition to transit service attributes and user characteristics, the composite costs of station access and use of competing for alternative modes are combined to estimate a random utility maximization based econometric model. Results showed that the age of the traveller seems to have the highest positive effect on longer-term retention. The ease of access to GO stations also plays a role as a higher access cost reduces long-term user retention. Further, alternative competing modes to GO rail reduces shorter-term retention (less than 5 years) but also increases longer-term retention. Transit-oriented land use policies that encourage heavy residential development in proximity to rail stations can lead to an increase in customer retention. Similarly, transit policies that aim to improve GO rail services through increasing train frequencies or improving capacity could also lead to higher customer loyalty.

Study on clearance optimisation and altitude correction of 750 kV AC side for UHVDC converter transformer

AC system which ±800 kV converter station access to commonly used 500 kV voltage level. With the construction of the Northwest Energy Base, a large number of ultra-high-voltage direct current (UHVDC) project are constructing. The backbone voltage in the northwest region is 750 kV. Phase or phase-to-ground clearance the converter transformer 750 kV AC side required will affect the length of the valve hall and the highest altitude of the project close to 3000 m. In order to optimise the 750 kV AC side and meet the engineering requirements in high altitude areas, this paper carried out the true phase-to-ground and phase–phase discharge characteristics test in the gap of 750 kV AC side in Beijing and Tibet, and the gap discharge voltage was then corrected for altitude. At last, the distance at different altitudes of 3000 m and below between the phase-ground and the phase-to-phase at the AC side of converter transformer is obtained. The results provide the design of UHV converter station in Northwest China with technical support.

Bicycle train intermodality: Effects of demography, station characteristics and the built environment

As public transport patronage levels increase worldwide, an issue many cities face is providing adequate infrastructure capacity for station access modes. A cost effective solution is to encourage the use of the bicycle for the ‘first mile’ link, particularly for rail commuters who currently drive but are within a cycling distance of the station. However, to promote cycling as a station access mode, a better understanding of the associated correlates are needed. This study aims to address this knowledge gap by identifying factors associated with increased rates of bicycle access to stations in Melbourne, Australia. Bicycle access counts at 207 metropolitan rail stations were analysed and factors related to the rail station catchment areas (demographic data and built/natural environment) and rail station characteristics were considered. Visual representation of the demographic and built/natural environment characteristics and eight generalized linear models were developed to identify significant factors. A higher number of cyclists riding to the station were associated with a range of factors including built/natural environments: low sloping terrain; greater proportion of low speed local roads, diverse land use mix and increased bicycle crash count density. Station attributes: availability of secure bicycle parking facilities, increased train patronage, higher train frequency during the morning peak period and demographic characteristics: increasing median age were also correlated with a growth in bicycle access counts to stations.

RPPM: A Request Pre-Processing Method for Real-Time On-Demand Data Broadcast Scheduling

Wireless on-demand data broadcasting (ODDB) has become the preferred method of disseminating data to a large number of mobile users. The rapid boom in client requests has resulted in an urgent demand for improved ODDB system capacity (number of service users), especially in client-intensive and request-frequent environments. There are two bottlenecks in ODDB systems: the base station access capacity and the server concurrency capability. However, existing algorithms do not consider these bottlenecks, leading to deficient performance in ODDB system capacity and broadcast efficiency. In this paper, a three-layer ODDB system architecture and a request pre-processing method (RPPM) are proposed. The innovations of this study are twofold: (1) The three-layer ODDB system architecture enhances the base station access capacity by introducing a virtual node layer to share the high load of the base station. (2) Based on the proposed architecture, the RPPM handles request merger and priority evaluation to reduce server concurrency and improve broadcast efficiency. The results of experiments and analyses reveal that the proposed method can significantly enhance the ODDB system capacity and obtain outstanding broadcast efficiency.

ПРИМЕНЕНИЕ СТАНДАРТА ШИРОКОПОЛОСНОГО ДОСТУПА IEEE 802.16 ДЛЯ ОПРЕДЕЛЕНИЯ ВЗАИМНОГО ПОЛОЖЕНИЯ КУБСАТОВ В СОСТАВЕ LEGA-SAT

It is considered the possibility of optimizing the use of the power capabilities of the cube-sat platform included in the "distributed satellite" to improve the performance of its payload. To optimize the use of energy capabilities, it was proposed to disconnect the onboard equipment of the command-and-telemetric radio link in the mode of regular operation of cube-sat in the "distributed satellite". To measure the current navigation parameters of cube-satellite in the conditions of group flight in the "distributed satellite" it is proposed to use the coordinates of the cube-satellite in the satellite coordinate system of the "distributed satellite" root satellite and the relative cube-relative velocity vector relative to the root satellite as the initial data. It is proposed to use a technique based on measurements of the distances between satellites in a "distributed satellite" and the projections of the vector of relative velocity for these distances to determine the coordinates of cube-sat in the satellite coordinate system. The features of the WiMAX broadband access protocol IEEE 802.16 protocols are examined to determine whether it is possible to perform mutual position measurements of satellites as part of a "distributed satellite" in one channel with information transmission. It pointed that the use of built-in means of measuring the range and access of mobile stations to the mobile WiMAX network makes it possible to perform measurements of the distance from the root satellite to the final satellite - cube-sat in the "distributed satellite". To perform the operations of measuring distances between the final satellites in the "distributed satellite", it is proposed to use the "competitive access zone" of the uplink sub-frame in the WiMAX network. A procedure for measuring the range between terminal satellites is proposed, based on measuring the propagation time of the distance measurement test signal between the assigned terminal satellites. It proposed a procedure for transmitting a test signal, taking into account the features of multiple access with orthogonal carrier separation (OFDMA). The proposed procedure can be implemented in a variant of the IEEE 802.16 standard network for application in a "distributed satellite"

Research on Active Power Automatic Control Strategy of Wind Farm Energy Station Access System

Wind farms are included in the grid Automatic Generation Control (AGC) will help for power system control. In order to minimize the imbalance between the active output of wind farm and the reference value, a power automatic control strategy for wind farm was proposed in the paper, which is considered the dispatching of safe operation of grid and the number of start and stop of wind turbines. The wind turbines in the wind farm were divided into three different categories according to the output characteristics and operation state of the wind turbines. By combining with the energy storage control of wind farm, the selection of power regulation turbines was carried out while considering the constraints such as the climbing rate and the power distribution value of the wind turbines. the proposed method effectiveness was verified with simulation example analysis, which could take full account of the individual information of wind turbines and make the output power adjustment of wind farm reach the optimization effect both in economy and safety.

Rails-Next-to-Trails: A Methodology for Selecting Appropriate Safety Treatments at Complex Multimodal Intersections

There are more than 212,000 at-grade railroad crossings in the United States. Several feature paths running adjacent to the railroad tracks, and crossing a highway; they serve urban areas, recreational activities, light rail station access, and a variety of other purposes. Some of these crossings see a disproportionate number of violations and conflicts between rail, vehicles, and pedestrians and bikes. This research focuses on developing a methodology for appropriately addressing the question of treatments in these complex, multimodal intersections. The methodology is designed to be able to balance a predetermined, prescriptive approach with the professional judgment of the agency carrying out the investigation. Using knowledge and data from the literature, field studies, and video observations, a framework for selecting treatments based on primary issues at a given location is developed. Using such a framework allows the agency to streamline their crossing improvement efforts; to easily communicate and inform the public of the decisions made and their reasons for doing so; to secure stakeholder buy-in prior to starting a project or investigation; to make sure that approach and selected treatments are more standardized; and to ensure transparency in the organization to make at-grade crossings safer for pedestrians and bicyclists, without negatively impacting trains or vehicles.

A hearing-care toolkit for young musicians: Combined use of a noise dose measurement app and acoustical manekin

Within a joint initiative with the Schulich School of Music at McGill University, the authors developed an original approach to raise awareness about hearing health by combining a participative assessment with a novel noise exposure risk indicator. The overall noise exposure is estimated using two complementary measurement systems addressing, respectively, the contribution determined by (i) the use of portable music players and (ii) music and non-music activities. The first system is a “listening-level measuring kiosk,” a freely accessible station on which students can place their own headphones or earphones and playback (at their preferred listening levels) music excerpts from their own playlist on an acoustical manikin. The second system is a personal, smartphone-based, “noise exposure” portable measurement device. Users start with an initial training and an audiometry screening, followed by the collection of exposure data during a 4-week assessment period. Personalized results are provided based on individual exposure profile and initial audiogram. The validation of the design of a novel noise exposure risk indicator is based on the feedback from a focus group of young musicians. This paper describes the measurement systems, assessment process, and preliminary results from the ongoing pilot studies.