Showing papers on "Bus network published in 2018"

Fast-charging station deployment for battery electric bus systems considering electricity demand charges

Abstract: Battery electric buses (BEBs) are considered a promising alternative for bus fleets to alleviate the growing environmental problems in urban areas, and fast-charging technology has been introduced to BEB systems to help electric buses provide uninterrupted service without the need to carry a large onboard battery. The general consensus is that fast-charging may lead to high electricity demand charges, thus compromising the competitiveness of electric bus systems. However, a majority of current electric bus fast-charging station deployment models ignore these charges. The present study addresses this gap by explicitly considering the electricity demand charges in the optimal deployment problem of fast-charging stations for battery electric bus systems. The problem is formulated as a mixed integer linear programming model with the objective of minimizing the total cost of vehicle batteries, fast-charging stations, energy storage systems, and electricity demand charges. Numerical studies based on a real-world bus network in Salt Lake City, Utah, are conducted to demonstrate the effectiveness of the proposed model. The results show that the proposed model can effectively determine the deployment of fast-charging stations, the design of vehicle battery sizes, as well as the installation of energy storage systems. This study demonstrates that energy storage systems are a potential remedy for high demand charges from fast-charging.

Applications of Complex Network Analysis in Electric Power Systems

Abstract: This paper provides a review of the research conducted on complex network analysis (CAN) in electric power systems. Moreover, a new approach is presented to find optimal locations for microgrids (MGs) in electric distribution systems (EDS) utilizing complex network analysis. The optimal placement in this paper points to the location that will result in enhanced grid resilience, reduced power losses and line loading, better voltage stability, and a supply to critical loads during a blackout. The criteria used to point out the optimal placement of the MGs were predicated on the centrality analysis selected from the complex network theory, the center of mass (COM) concept from physics, and the recently developed controlled delivery grid (CDG) model. An IEEE 30 bus network was utilized as a case study. Results using MATLAB (MathWorks, Inc., Nattick, MA, USA) and PowerWorld (PowerWorld Corporation, Champaign, IL, USA) demonstrate the usefulness of the proposed approach for MGs placement.

Distributed Event-Based State Estimation for Networked Systems: An LMI Approach

Abstract: In this paper, a dynamic system is controlled by multiple sensor-actuator agents, each of them commanding and observing parts of the system's input and output. The different agents sporadically exchange data with each other via a common bus network according to local event-triggering protocols. From these data, each agent estimates the complete dynamic state of the system and uses its estimate for feedback control. We propose a synthesis procedure for designing the agents’ state estimators and the event triggering thresholds. The resulting distributed and event-based control system is guaranteed to be stable and to satisfy a predefined estimation performance criterion. The approach is applied to the control of a vehicle platoon, where the method's tradeoff between performance and communication and the scalability in the number of agents are demonstrated.

Modelling the net traffic congestion impact of bus operations in Melbourne

Abstract: Bus services can be seen as a way to reduce traffic congestion where they can encourage a mode shift from car. However, they can also generate negative effects on traffic flow due to stop-start operations at bus stops. This paper aims to assess the net impact of bus operations on traffic congestion in Melbourne. The methodology used to achieve this aim comprised of three main stages. First, a primary survey was conducted to determine the mode shift from bus to car when buses are unavailable. This figure was used to estimate the positive impact of buses on relieving congestion. Second, the negative impact of buses was investigated by considering the effect of bus stop operations on vehicle traffic flow using microsimulation. Finally, the net effect was estimated by contrasting congestion measures determined from a traditional four step model between two scenarios: ‘with bus’ and ‘without bus’. The results indicated that Melbourne’s bus network contributes to reduce the number of severely congested road links by approximately 10% and total delay on the road network by around 3%. The highest congestion relief impact was found in inner Melbourne with a 7% decrease in vehicle time travelled and total delay, and 16% decrease in the number of heavily congested road links. In inner areas, the level of congestion is relatively high so the mode shift from car to bus, even if not as high as middle and outer areas, have a significant effect on relieving traffic congestion. Areas for future research are suggested such as investigating the long-term effect of buses on traffic congestion.

Network-based transportation system analysis: A case study in a mountain city

Abstract: In order to characterize the structural features of public transportation systems (PTSs) in mountain cities, this paper systematically examines the robustness of urban transportation networks in Chongqing, a famous inland mountain city in China, and reveals the community feature of mobility patterns of residents. First, according to the transportation information (i.e., bus route data and metro route data) in Chongqing, three static network models, i.e., a bus network, a metro network, and a bus-metro transit network, are proposed based on the spaces L and P. More specifically, as a multiplex network, the bus-metro transit network is modeled for depicting the coupled structure between the bus network and the metro network. By analyzing the attack tolerance of transportation networks under the condition of different attack patterns, we find that the inter-layer coupling between the bus network and the metro network can improve the robustness of an urban transportation system. Furthermore, the community structure of mobility patterns of residents is revealed based on passenger information (i.e., smart-card data) of the metro system, which is caused by the regionalization of residential areas in a mountain city. Experimental studies above can provide guidance for the design and optimization of a PTS.

IoT-based Bus Location System Using LoRaWAN

Abstract: This paper introduces an IoT-based bus location system that can improve the service quality of the bus network and improve the efficiency of operation management. The proposed system provides the bus approach information by utilizing the location and delay information of the bus, and can be realized with low operational cost. The principle of LoRaWAN is used to collect the location information of all buses and deliver the calculated delay information to smart bus stops using electronic paper. A prototype system was implemented, a basic evaluation experiment was conducted and trial calculations for the cost were performed. The corresponding results confirmed that the system can be realized at a lower cost than the bus location system using 3G/LTE.

Resilience analytics: coverage and robustness in multi-modal transportation networks

Abstract: A multi-modal transportation system of a city can be modeled as a multiplex network with different layers corresponding to different transportation modes. These layers include, but are not limited to, bus network, metro network, and road network. Formally, a multiplex network is a multilayer graph in which the same set of nodes are connected by different types of relationships. Intra-layer relationships denote the road segments connecting stations of the same transportation mode, whereas inter-layer relationships represent connections between different transportation modes within the same station. Given a multi-modal transportation system of a city, we are interested in assessing its quality or efficiency by estimating the coverage i.e., a portion of the city that can be covered by a random walker who navigates through it within a given time budget, or steps. We are also interested in the robustness of the whole transportation system which denotes the degree to which the system is able to withstand a random or targeted failure affecting one or more parts of it. Previous approaches proposed a mathematical framework to numerically compute the coverage in multiplex networks. However solutions are usually based on eigenvalue decomposition, known to be time consuming and hard to obtain in the case of large systems. In this work, we propose MUME, an efficient algorithm for Multi-modal Urban Mobility Estimation, that takes advantage of the special structure of the supra-Laplacian matrix of the transportation multiplex, to compute the coverage of the system. We conduct a comprehensive series of experiments to demonstrate the effectiveness and efficiency of MUME on both synthetic and real transportation networks of various cities such as Paris, London, New York and Chicago. A future goal is to use this experience to make projections for a fast growing city like Doha.

Characterization of Substation Process Bus Network Delays

Abstract: This paper presents the characterization of network delays in an IEC61850 process bus substation area network, both through theoretical analysis and simulations. Several design targets were defined considering the recommendations of standards and good design practices: number of network hops, total network delay, probability of the delay being exceeded, link load, network topology and availability. An analytical delay estimation methodology is proposed, considering both the steady-state traffic and traffic resulting from a breaker failure event. A complete substation is taken as an example for characterizing the network delays, considering a star network topology. Simulations allow to obtain the cumulative distribution functions and percentile values of network delays. Results show a good agreement between the simulation and the analytical analysis. While the delay is best characterized statistically through simulation, finding the maximum network delay through simulations can be very time consuming, making the analytical analysis more suitable.

Smart City L’Aquila: An Application of the “Infostructure” Approach to Public Urban Mobility in a Post-Disaster Context

Abstract: Ever since the earthquake of April 6, 2009 hit the city of L’Aquila, Italy, the city has been facing major challenges in terms of social, physical, and economic reconstruction. The system of public urban mobility, the bus network, is no exception with its old bus fleet, non-user-friendly information, and poor scheduling. This paper argues that the public transportation system of L’Aquila could be improved towards smart mobility models without large infrastructure investment by leveraging the “infostructure” approach, digital technologies, open data, and open source software. This work presents the digitization and geo-referencing procedure, software architecture, and the web and mobile apps that have been developed to improve the information flow available to citizens and to increase the user-friendliness of the transportation system. Future research will seek to make use of the data and develop applications to perform a public transport accessibility analysis of major points of interest throughout the city.

Identifying hub stations and important lines of bus networks: A case study in Xiamen, China

Abstract: Hub stations and important lines play key roles in transfers between stations. In this paper, a node failure model is proposed to identify hub stations. In the model, we introduce two new indicators called neighborhood degree ratio and transfer index to evaluate the importance of stations, which consider neighborhood stations’ degree of station and the initial transfer times between stations. Moreover, line accessibility is developed to measure the importance of lines in the bus network. Xiamen bus network in 2016 is utilized to test the model. The results show that the two introduced indicators are more effective to identify hub stations compared with traditional complex network indicators such as degree, clustering coefficient and betweenness.

Network-level Optimization of Bus Stop Placement in Urban Areas

Abstract: Bus stops provide accessibility to public transit service, whereas they also influence the efficiency of mobility due to the extra dwell time. The decision of bus stop locations is a tradeoff between access coverage and mobility. This paper formulates a biobjective optimization model of bus stop placement problem at the network level. Two objectives are pertinent to the improvement of mobility: minimization of total dwell time at stops and minimization of total number of bus stops. Access coverage is constrained to ensure a certain level of accessibility. The issue of stop congestion and its effect on road traffic flow is also considered in the model. The model is applied to a case study of the bus network in urban areas of Yancheng, China. The results show that the proposed model can be efficiently solved by CPLEX to obtain Pareto optimal solutions for real-case problems.

Real-Time-Simulation of IEEE-5-Bus Network on OPAL-RT-OP4510 Simulator

Abstract: The Real-Time Simulator tools have high computing technologies, improved performance. They are widely used for design and improvement of electrical systems. The advancement of the software tools like MATLAB/SIMULINK with its Real-Time Workshop (RTW) and Real-Time Windows Target (RTWT), real-time simulators are used extensively in many engineering fields, such as industry, education, and research institutions. OPAL-RT-OP4510 is a Real-Time Simulator which is used in both industry and academia. In this paper, the real-time simulation of IEEE-5-Bus network is carried out by means of OPAL-RT-OP4510 with CRO and other hardware. The performance of the network is observed with the introduction of fault at various locations. The waveforms of voltage, current, active and reactive power are observed in the MATLAB simulation environment and on the CRO. Also, Load Flow Analysis (LFA) of IEEE-5-Bus network is computed using MATLAB/Simulink power-gui load flow tool.

Cost-Benefit Analysis of Electric Bus Fleet with Various Operation Intervals

Abstract: Electric buses are particularly suitable for city and suburban routes due to zero local exhaust and noise emissions. The operation schedule interval defines the charging power, bus fleet size and total cost of ownership of a bus. We propose a novel cost-benefit method for the scheduling of an electric city bus fleet on a single route. Three different charging infrastructure scenarios were considered. In the first scenario, only one charging station was used. The second scenario considered two charging stations that were located at the same terminus. In the third scenario, two charging stations were located at opposite terminuses. The costs and utilization rates of the buses were analyzed with operation intervals up to 40 minutes. The first scenario with a single charging station had the lowest costs for the entire bus fleet system when the utilization rate was considered. Furthermore, the results show that certain schedule intervals are more cost-beneficial in terms of vehicle specific life-cycle costs than others. In the future, the proposed method is expanded to aid the design of bus network scheduling under energy demand uncertainty.

Cost Optimization of an Opportunity Charging Bus Network

Abstract: This study focusses on reducing the battery size requirements of electric busses using battery charging and speed profile optimization. To minimize the energy consumption costs and the battery size, an opportunity charging city bus networks have been investigated. An electric bus architecture, traffic, weather and road conditions, as well as the driver behaviors have been modelled to simulate the overall system and predict the energy consumption. Optimization algorithm is developed to determine the optimal driving cycle and the charging time on each bus stop. The algorithms are tested on case studies, which verified that the proposed approach reduces the energy consumption and battery size requirements of electric busses.

Trip comfort-based bus trip scheme evaluation system

Abstract: A trip comfort-based bus trip scheme evaluation system disclosed by the present invention comprises a bus network basic information acquisition unit, a passenger trip scheme generation unit, a bus passenger flow information real-time acquisition unit and a comfort-based trip scheme recommending unit. When the passengers select the buses for trips, a bus network basic information database can be called, the passenger trip feasible schemes can be provided, and based on the passenger trip comfort evaluation indexes of the schemes, such as the jam conditions, the walking conditions, etc., the comforts of the schemes are analyzed, thereby recommending an optimal scheme. The trip comfort-based bus trip scheme evaluation system of the scheme fully considers the bus jam conditions, satisfies the personalized and refined operation requirements of the public transport, facilitates balancing the passenger flow volume of the public transport, and enables the service level of the public transport to be improved.

Communication system, vehicle, and monitoring method

Abstract: A communication system includes a first electronic device, and a second electronic device that monitors a state of the first electronic device. The first electronic device includes a transmitter that transmits a first frame including a first verification value forming a Hash chain to a bus network. The second electronic device includes a storage unit that stores the first verification value included in the first frame received from the bus network. The transmitter transmits, after transmission of the first frame, a second frame including a second verification value forming the Hash chain to the bus network. The second electronic device further includes a determination unit that determines that the state of the first electronic device is normal when the second verification value included in the second frame received from the bus network and the first verification value stored in the storage unit construct the Hash chain.

Modeling and Performance Analysis of Data Flow for HSR and PRP under Fault Conditions

Abstract: To ensure reliability and availability of IEC 61850 based substation automation systems (SAS), High-availability Seamless Redundancy (HSR) or Parallel Redundancy Protocol (PRP) or both are used. This paper presents the analysis and comparison of the device connection capability and data recovery time performance for HSR and PRP networks. An IEC 61850 based substation with both HSR and PRP bays is designed and modelled using the OPNET. The device connection capabilities, e.g. the maximum number of devices that can be connected to a fixed bandwidth network, under various operating conditions are evaluated and studied. A comparison study between an HSR network and PRP network has also been carried out. The results show that the device connection capability of an HSR network can be reduced by as much as half as each packet is duplicated in the HSR network. The results also show that the Ethernet bandwidth utilization is decreased as the number of devices increases. The work may help utilities to determine the number of devices that can be connected into an HSR/PRP process bus network in order to ensure the network performance.

Synchronization and Aggregation of Nonlinear Power Systems with Consideration of Bus Network Structures

Abstract: We study nonlinear power systems consisting of generators, generator buses, and non-generator buses. First, looking at a generator and its bus' variables jointly, we introduce a synchronization concept for a pair of such joint generators and buses. We show that this concept is related to graph symmetry. Next, we extend, in two ways, the synchronization from a pair to a partition of all generators in the networks and show that they are related to either graph symmetry or equitable partitions. Finally, we show how an exact reduced model can be obtained by aggregating the generators and associated buses in the network when the original system is synchronized with respect to a partition, provided that the initial condition respects the partition. Additionally, the aggregation-based reduced model is again a power system.

Protecting ECUs and Vehicles Internal Networks

Abstract: The Automotive Industry is on the verge of digital transformation. The race building fully connected and autonomous cars has begun and it will redefine the way we have been using transportation systems. The goal of connected cars is to provide personalized and safe driving, but connectivity is opening the doors for cyber-attacks. Control Area Network (CAN)-bus is a serial car bus network that connects Electronic Control Units (ECUs), sensors and actuators in a system or subsystem for control applications. Thousands of signals are recorded on the CAN-Bus which can give almost real-time information about the car, driver and the surroundings. This paper proposes a conceptual approach for intrusion detection and prevention systems (IDPSs) for connected cars and an overview of machine learning algorithms for anomaly detection as part of intrusion detection.

A Data-Driven Approach to Prioritizing Bus Schedule Revisions at New York City Transit:

Abstract: Over two million trips are taken every weekday across the New York City Transit (NYCT) bus network Revising the schedules for each of these routes is a labor-intensive process, and because of limi

Fault injection method and apparatus of FC-AE-1553 bus

Abstract: The invention provides a fault injection method and apparatus of an FC-AE-1553 bus. The method comprises the following steps: in a message transmission process of the FC-AE-1553 bus, obtaining a current fault detection demand; and performing fault injection on at least one sequence in a command sequence, a data sequence and a state sequence in the message according to the current fault detection demand so as to perform fault detection on the FC-AE-1553 bus. According to the method and apparatus provided by the invention, in view of the fault detection demand, corresponding fault injection modes are respectively designed, various faults in the FC-AE-1553 bus are simulated, robustness and robustness tests are performed in view of the FC-AE-1553 bus network or device, and fault detection demand of the current FC-AE-1553 bus is comprehensively satisfied.

An Active Equalization Circuit Based on the Share Bus for series Li-Ion Battery

Abstract: An active cell balancing circuit based on the Share Bus for Li-ion batteries is proposed in this paper. The equalization circuit has the following advantages. Firstly, the Share Bus topology can achieve simultaneous equalization of all batteries, thereby leading to a high balancing speed. Secondly, the proposed circuit adopts zero-voltage control technology which can reduce the power loss of the MOSFET. Besides, the number of switches in the circuit is equal to the number of the battery cells. So the proposed circuit has a lower cost. An experiment was carried out with 12-cell batteries to verify the feasibility of the method.

Slave-to-slave communication in i3c bus topology

Abstract: Systems, methods, and apparatus for a slave-to-slave communication over a serial communication link are provided. An apparatus includes an interface adapted to couple the apparatus to a serial bus, and a processing circuit. The processing circuit may be configured to receive a request for a slave-to-slave transaction while servicing an in-band interrupt detected on a serial bus, the request for the slave-to-slave transaction indicating a source address and a target address, generate a first frame that includes the source address, the target address and a command code configured to initiate the slave-to-slave transaction between the source slave device and at least one target slave device, and initiate a data transfer on the serial bus between the source slave device and the at least one target slave device by transmitting the first frame on the serial bus.

SpaceFibre plug and play-based satellite-borne network management method

Abstract: The invention discloses a SpaceFibre plug and play-based satellite-borne network management method, belonging to application field of satellite-borne space buses. The method comprises the steps that aSpaceFibre bus network is constructed at first, and a SpaceFibre plug and play communication protocol is designed; then a network manager sends a device static port scan packet to routers, and a physical address of the network manager and a connection relationship of a router and another router are determined; finally, each order of router forwards a static scan packet to each terminal device toparse and reply, and the network manager receives a reply packet and then determines a physical address of each terminal device; the network manager monitors the bus network in real time and initiatesdynamic network scanning, identifies the quantity of routers and a connection state of every two routers automatically, and updates a network topological structure map after the device is plugged orunplugged; and the network manager controls the terminal device to send a data packet to the network manager. Network addressing is easy and convenient, fewer system space resources are used, the system performance is improved, and unnecessary workload is saved.

Optimum Position and Optimum Size of the Distributed Generators for Different Bus Network Using Genetic Algorithm

Abstract: The computation of excellent location and the optimum size of Distributed generator (DG) play an important role in electrical power system. It results to reduced power losses and increased voltage profiles. In a real time situation finding the suitable DG position and size is difficult due to various restriction in the distribution system. An advance technique for placement and sizing of DG in electric power system is carried out in this paper. This paper introduces an Optimization technique called Genetic algorithm (GA) for finding an optimum place and size for DG. In recent years the government subsidized programs and improved Distribution network has increased the use of Distributed generator(DG) in commercial and domestic electrical power output. GA fitness function is applied to voltage constraints, active & reactive power losses constraints & DG size constraints. This method is carried out on 14 buses, 30 bus, 57 bus distribution system. The optimization process has been examined using Newton Raphson (N-R) method and by Genetic Algorithm (GA) method for different bus system.

Isolated microgrid and energy management system thereof

Abstract: The invention relates to an isolated microgrid and an energy management system thereof. The isolated microgrid comprises the units such as a diesel engine, a photovoltaic power generation array, a fan, a battery energy storage system and a load and adopts a common bus topology structure, wherein the photovoltaic power generation array is connected to the grid through a photovoltaic inverter, the fan is connected to the grid through a fan rectifier, the battery energy storage system is connected to the grid through an energy storage converter, and the load is connected to a bus. The junction ofeach branch and the bus is equipped with a switch and an electric meter, wherein one end of the switch is connected with the bus, the other end of the switch is connected with the electric meter, andthe other end of the electric meter is connected with the branch. The switch is used for controlling disconnection of the branch, and the electric meter collects information such as the voltage, current, power, power factor and electric quantity of the branch. The energy management system of the isolated microgrid is composed of a PLC based local control system and an intelligent cloud platform.The energy management system of the isolated microgrid adopts an expert strategy based operation control strategy.