Intermediate Stations Research Articles

A distributed measurement architecture for inferring TCP round-trip timesthrough passive measurements

The round-trip time (RTT), defined as the time elapsed for transmission of a data packet to travel from one endpoint to the other and back again, is an important parameter for Internet quality. This paper proposes an extended version of the well-known SYN/ACK (SA) methodology for passively measuring the RTTs over Transmission Control Protocol (TCP) connections. Differently from the original version of the SA methodology and the rest of studies in the related literature, the proposed passive methodology measures not only the total RTT of an end-to-end connection but also the proportion of the existing connection sections on this entire RTT in a passive way if the connection between client and server is established via intermediate stations. A distributed measurement architecture has been designed that implements the extended SA methodology. Through tests in a controlled laboratory environment, various verification and performance evaluation experiments were conducted to determine the accuracy level of the measurement technique and how the distributed architecture behaves regarding resource requirements as the amount of incoming network traffic increases. Accuracy verification experiments show that on average about 92.66 % of the passive measurements are within 10 % or 5 ms, whichever is larger, of the RTT that \textit{ping} would actively measure. Furthermore, the results reveal that using today's commodity hardware, the designed distributed architecture exhibits acceptable satisfactory scaling performance and can practically be used to passively measure RTTs of each hop within medium-sized communication networks.

Solutions for increasing the capacities of cable cars

Cableways have some potential to be used in urban public transportation, particularly uni-directional aerial cable cars with circulating cabins, called gondolas. They have several advantages, but two major problems must be solved: the capacity and the operating speed are not competitive when compared to other means of urban mass transport because of boarding procedures and slowing down and accelerating on intermediate stations. In this paper constructional solutions are presented. Boarding takes place on at least two platforms; these could be on the same level or on separate levels. At intermediate stations certain cabins are diverted to the extra platform while the majority of cabins travel with unreduced speed. Following this constructional approach, the nominal capacity of gondolas could be doubled while increasing the operational travel speed on lines with lot of intermediate stops.

Charging Schedule for Load Peak Minimization on Large-Scale Electric Bus Depots

The city of Hamburg has decided to electrify its bus fleets. The two public transportation companies in this city expect to operate up to 1500 buses by 2030. In order to accomplish this ambitious goal, both companies need to build an appropriate charging infrastructure. They have both decided to implement the centralized depot charging concept. Buses can therefore charge only at the depot and do not have the possibility for opportunity charging at intermediate stations. The load profile of such a bus depot is highly dependent on the charging schedule of buses. Without an intelligent scheduling system, the buses charge on demand as soon as they arrive to the depot. This can lead to an unevenly distributed load profile with high load peaks, which is problematic for the local grid as well as for the equipment dimensioning at the depot. Charging scheduling on large-scale bus depots is a relatively new and poorly researched topic. This paper addresses the issue and proposes two algorithms for charging scheduling on large-scale bus depots with the goal to minimize the peak load. The schedules created with the proposed algorithms were both tested and validated in the Bus Depot Simulator, a cosimulation platform used for bus depot simulations.

Numerical simulation for an estimation of the jacking force of ultra-long-distance pipe jacking with frictional property testing at the rock mass–pipe interface

In ultra-long-distance rock micro-shield pipe jacking, the pipe wall friction resistance is a key factor that determines the magnitude of the jacking force and the layout of the intermediate jacking stations (IJSs), whereas the pipe-rock contact condition is the critical factor controlling the pipe string wall friction resistance. This paper aims to reveal the variation law of the friction resistance between the outer wall of a large-section of concrete pipe string and the surrounding rock during construction via ultra-long-distance rock micro-shield pipe jacking. To that end, the shear friction behaviour and mechanical mechanism was investigated between sandstone and concrete pipe string walls under seven different complex contact conditions (primarily considering various combinations of the three substances, namely, extra-pipe in situ debris, bentonite slurry and sand-laden waste mud at the pipe-rock contact surface) through direct rock shear tests based on the actual pipe-rock contact condition at the Guanjingkou Water Conservancy Project in Chongqing. The average friction coefficient (AFC) of the residual phase of the contact surface under 7 contact conditions was obtained by friction testing. Combined with the contact situation between the surrounding rock and pipe strings at the stage of a rapidly increasing jacking force, a three-dimensional finite element model was established, and the displacement control method was used to simulate the jacking. The comparison with the field monitoring results shows that the numerical model can accurately predict the jacking force and verify the reliability of the AFC parameters in the numerical calculation. Therefore, the combination of indoor testing and the finite element method can be applied to study the jacking force for other ultra-long rock micro-shield pipe jacking applications.

Master-Slave Collaboration System of Unmanned Surface Vehicle and Robotic Fish

A brief introduction to the master-slave collaboration system of unmanned surface vehicle (USV) and robotic fish, which consists of an upper computer, master and slave is given in this paper. The upper computer set in the control center communicates with the master-slave through the wireless communication network. The master is set on USV. The slave is set on each robotic fish. Because the system adopts the USV as an intermediate station for signal transfer. The underwater detector, namely robotic fish, detect the signal and pass it to the upper machine by the USV, which enhances the power and increases the distance of signal transmission, improves the signal stability and the radius of operation activities of the whole robotic fish due to the close distance between fish and boats so that they can carry out real-time communication.

Hybrid quantum repeater for qudits

We present a "hybrid quantum repeater" protocol for the long-distance distribution of atomic entangled states beyond qubits. In our scheme, imperfect noisy entangled pairs of two qudits, i.e., two discrete-variable $d$-level systems, each of, in principle, arbitrary dimension $d$, are initially shared between the intermediate stations of the channel. This is achieved via local, sufficiently strong light-matter interactions, involving optical coherent states and their transmission after these interactions, and optical measurements on the transmitted field modes, especially (but not restricted to) efficient continuous-variable homodyne detections ("hybrid" here refers to the simultaneous exploitation of discrete and continuous variable degrees of freedom for the local processing and storage of entangled states as well as their non-local distribution, respectively). For qutrits we quantify the light-matter entanglement that can be effectively shared through an elementary lossy channel, and for a repeater spacing of up to 10 km we show that the realistic (lossy) qutrit entanglement is even larger than any ideal (loss-free) qubit entanglement. After including qudit entanglement purification and swapping procedures, we calculate the long-distance entangled-pair distribution rates and the final entangled-state fidelities for total communication distances of up to 1280 km. With three rounds of purification, entangled qudit pairs of near-unit fidelity can be distributed over 1280 km at rates of the order of, in principle, 100 Hz.

IMPROVEMENT OF SUPERVISORY CONTROL OF TRAIN MOVEMENT BY MEANS OF INTRODUCTION OF OPERATIONAL ZONES

Purpose. The work is aimed to investigate the feasibility of transferring automatic control to low-density stations of the sections (according to the principle of supervisory control of trainline) to the operators at principal stations. Methodology. The article analyzes the work of heavy traffic sections of the Ukrainian Railways JSC. It was found out that the information workload of dispatchers who control the train movement at the sections of the main course, constantly exceeds the permissible level. The possibility of using the technology of supervisory control of train movement by the introduction of operational zones has been investigated. Findings. The authors found out that the capacity of receiving and departure tracks at the stations of the sections is extremely limited. The occupancy of run-around tracks by the out-of-work trains hinders any regulatory measures at the sections. Trains pass one after another without giving priority, that is, they pass through the section in the order in which they entered it. Due to the limited number of tracks at the pre-section intermediate station, freight trains are placed for run-around by the passenger ones at the distant approaches. This leads to a loss of service speed and reduces the level of utilization of the sections` working capacity. The introduction of operational zones will significantly reduce information flows and facilitate the work of the train dispatchers, create the necessary conditions for creative decision-making on the inter-sectional regulation, and will contribute to increase in the service speed of trains. Originality. The article developed a new technology to improve the management of train sections by dividing them into operational zones. In each zone, consisting of two or three run-arounds, the duty officer of the principal station, performing in this case the functions of the train dispatcher, can control the train movement. Practical value. It has been proposed to put trains from technical stations that idle due to uneven movement, especially the trains from the terminal stations (division points) of the locomotive circulation sections, to reserve routes of the pre-section intermediate stations. Laying the reserve tracks and their maintenance, taking into account the periodicity of use and reduced permissible speed, can be allowed according to less tight standards for the construction of the roadbed, ballast section, sleeper density, taking into account the use of switches and decommissioned tracks.

Energy consumption optimization of train operation for railway systems: Algorithm development and real-world case study

Traction energy is the main component of railway operation energy, and a timetable that predefines the running time of train operation can be used to determine the traction energy consumption. This study proposes a bi-level model that optimizes timetables to achieve the energy-saving control of railway systems. The upper level of the model ensures the relative stability of the timetable while maintaining railway safety constraints, which makes train operations more convenient for the railway sector as well as passengers; while the lower level of the model optimizes the arrival and departure time among intermediate stations to minimize the energy consumption of each train. Then, a unified iterative optimization algorithm combining particle swarm is developed to solve the model, and a timetable that ensures energy consumption optimizations is thus obtained. A case study using actual operation data from the Beijing-Shanghai high-speed railway is developed to illustrate the proposed method. Results show that the total energy consumption is reduced by more than 7.6%, and the average adjustment time for each distance interval is approximately 1 min, which maintains the stability of the original timetable.

The Roman road Montana – Nicopolis ad Istrum – Marcianopolis – Odessos

The road crossing the northern half of today’s Bulgaria from west to east runs north of the Balkan Mountains and parallel to the limes road. It is only partially represented in the Tabula Peutingeriana and Itinerarium Antonini. The segment represented in the Tabula Peutingeriana is between Melta and Marcianopolis. The only intermediate station between the two is Nicopolis ad Istrum. Th e segment Odessos - Marcianopolis appears only in Itinerarium Antonini, and is considered part of the coast road. The route segments that do not appear on the ancient cartographic sources were reconstructed based on field research that led to the identifi cation of ancient road segments, traces of settlements, stations, as well as on the basis of inscriptions on milestones. These were found in Topolite, Povlijanovo, Devnija, Odessos, and Tlačane. Except for the latter, they fall chronologically in the period between the reign of Gordian III (238-244) and the reign of Tacitus (275-276). Since the pieces are relatively late, the issue of dating the road is still an open question, as well as its role, in the scientific literature several suppositions were advanced over time.

Dynamic Models of Cargo Flow Organization on Railway Transport

This article is devoted to mathematical modeling of the process of organization of railway transportation on the transport network, which is a long section of the road with a large number of intermediate stations and located between them railway tracks for temporary storage of cargo. We investigate a model that predicts dynamics of congestion of stations and streams arising in the transportation network, under a given procedure traffic that uses the two technologies, the same for all stations. The first technology is based on the normative rules of interaction of neighboring stations. According to it, the intensity of the reception and dispatch of goods at an arbitrary station should depend on the workload of neighboring stations. The second technology uses the technical capabilities of the stations, and is based on the interaction of the station with neighboring railway tracks. An integral part of the organization of cargo transportation is a control system. This model uses a simple control system, which is that the volume of goods at neighboring stations must coincide with the time lag common to all stations. This model is described by a system of differential equations satisfying nonlocal linear restrictions. For this model the modes of cargo transportation satisfying the given control system are investigated. Such modes are described by solutions of the traveling wave type and two types of their expansions. One type of expansion is associated with the adjustment of transportation technologies and allows discontinuous solutions, the second type of expansion is associated with the weakening of the control system and allows the feasibility of nonlocal linear constraints with a given error. Stationary modes of transportation are investigated for stability.

Standardisation of maglev transportation systems in Russia

Existing regulatory framework in Russia does not include a full set of rules and standards needed, as the main document is absent – Safety Regulations Governing Maglev Transportation Systems. However, in this case the Russian Legislation provides for development and application of a special document, namely Special Technical Conditions (STC). These technical safety requirements to a capital construction object, that include either supplementary technical conditions to those which have not been set yet or are lacking in terms of safety, as well as deviations for the set requirements. Using the international and national experience, the authors and their colleagues have designed nine STC for MLTS. These are “General Design Requirements”, “Guideway”, “Substructure, Artificial Structures, Junctions and Crossings”, “Terminals, Intermediate Stations, Maintenance Facilities and Buildings”, “Propulsion and Power Supply System”, “Train Control System”, “Communication Systems”, “Vehicles”, “Integrated Safety System”. Also, as a result of the study, the English-Russian (Russian-English) MLTS Explanatory Dictionary was compiled.

HS2 railway, UK: route optioneering

The company HS2 Ltd was set up by the UK government in January 2009 with an initial brief to report on options for High Speed Two, a high-speed railway between London and the West Midlands. This was to include access to London and Birmingham city centres, but with the potential for future extension northwards. Options were also required for intermediate stations and connections to the Great Western main line, the Elizabeth line and High Speed 1. From the outset the Department for Transport and HS2 Ltd applied government business case methodology for preparing and assessing proposals in order to derive the best scheme and to be able to justify the choices during the consultation and approval process. An ‘initial preferred route’ was published in 2010 and, following modification, there was a national public consultation in 2011. The hybrid bill for phase 1 was deposited in November 2013 and royal assent was obtained in February 2017. Throughout, a rigorous process of longlisting possible options, shortlisting and selection was adopted. At each stage the proposals became more detailed as the route, design and mitigations were developed. Consequently, the selection criteria, costing and evaluation also became more detailed and specific.

The investigation of ultra-long-distance concrete pipe stuck in quartz sandstone formation using numerical simulation

During mountainous area construction by long-distance pipe jacking, the pipe stuck encountered. To reveal the cause of the pipe stuck, this paper investigates the pipe surface frictional resistance corresponding to different burial depths and surrounding rock parameters by ADINA finite element analysis. Parameter sensitivity analysis results show that the cohesion effect on the frictional resistance was small, the frictional resistance tended to decrease markedly with the increasing other rock mechanical parameters and the decreasing burial depth and friction coefficient of the pipes. After continuing to consider the prerequisite of simultaneously changing the elastic modulus, internal friction angle and burial depth conditions, a solution of the maximum number of pipes driven by a single intermediate jacking station (IJS) was reduced from 59 to 40 was proposed based on an integration of simulations with the field monitoring results. Finally, the pipe jacking project was successfully completed after adopting the improvement proposals.

Can broad-band earthquake site responses be predicted by the ambient noise spectral ratio? Insight from observations at two sedimentary basins

Site-effect assessments performed through earthquake-based approaches, such as the standard spectral ratio (SSR), require good quality records of numerous earthquakes. In contrast, the use of ambient noise appears to be an attractive solution for ease and rapid computation of site responses with sufficient spatial resolution (microzonation), especially in low seismicity areas. Two main approaches are tested here: the horizontal-to-vertical spectral ratio (HVSR) and the noise-based SSR (SSRn). The HVSR uses the relative amplitude of the horizontal and vertical components of the ambient noise. Instead, the SSRn defines the spectral ratio between the seismic noise recorded simultaneously at a site and at a rock reference station, similar to earthquake-based SSR. While the HVSR is currently used in hundreds of site-specific studies, the SSRn approach has been gradually abandoned since the 1990s. In this study, we compare the results obtain from these two approaches with those of earthquake-based SSR. This comparison is carried out for two sedimentary basins, in Provence (southeastern France) and in Argostoli (western Greece). In agreement with the literature, the HVSR does not provide more than the fundamental resonance frequency of the site (f0). The SSRn leads to overestimation of the SSR amplification factors for frequencies higher than the minimal f0 of the basin (f0min). This discrepancy between SSRn and SSR is discussed, and appears to be mainly dependent on the local geological configuration. We thus introduce the hybrid standard spectral ratio (SSRh) approach, which aims to improve upon the SSRn by adding an intermediate station inside the basin for which the SSR is known. This station is used in turn as a local reference inside the basin for the SSRn computation. The SSRh provides site transfer functions very similar to those of the SSR, in a broad frequency range. Based on these results, the SSRn (or SSRh) should be further tested and should receive renewed attention for microzonation inside sedimentary basins.

Review of BIM literature in construction industry and transportation: meta-analysis

PurposeBuilding information modeling (BIM) is a process of generating and managing building data during the building’s life cycle. To increase productivity in building design and construction, BIM uses three-dimensional (3D) real-time, dynamic building modeling software. Because of its versatile features, BIM use is on the rise and researchers are exploring its application in new disciplines. The purpose of this study is to map out how BIM is used in the construction industry, while identifying and highlighting the research gaps in the literature.Design/methodology/approachTo investigate the status quo of knowledge about BIM, the authors conducted a comprehensive literature review. They applied and extended a methodology for reviewing BIM-related publications through a four-dimensional meta-analysis system and its categories, which has been partially adapted previously.FindingsMajority of studies applying BIM for the construction phase of civil engineering projects were done within universities; none used BIM for the construction of intermediate railway stations.Practical implicationsTo increase the construction efficiency of intermediate railway stations, applying the BIM concept for generation and management of station data should be considered for future research.Originality/valueFurthermore, one of the main goals of this research paper is to explore the adoption of BIM in civil engineering construction projects, in particular the construction of intermediate railway stations.

The Physiochemical, Biological Quality and Seasonal Variability of River Ganges in Varanasi, Uttar Pradesh, India

Background: The Ganga River is a life-line, a symbol of purity and virtue for countless people of India. Nearly all the sewage, industrial effluent, runoff from chemical fertilizers and pesticides used in agriculture within the basin, and large quantities of solid waste, including thousands of animals carcasses and hundreds of human corpses are dumped in the river everyday which posed a considerable public health threat to the religious bathers and a large number of people living along the river who uses Ganges water for drinking and other household purposes. Objective: To assess the physiochemical and biological quality of river Ganges water and to study the seasonality pattern of pollution of River Ganges. Materials and Methods: Two points namely Samne ghat and Rajghat (entry and exit point of Ganga into the city) were selected as the first and the last sampling stations, beside 8 other intermediate sampling stations to assess the physiochemical and biological quality of River Ganga water. The study was conducted from April 2013 to March 2014 and this period was crudely divided into three seasons viz Winter, Summer and Rainy season for the purpose of studying seasonality pattern of pollution. Results: As the river progress through city of Varanasi, Total dissolved solids (TDS), Chloride, Conductivity, Biochemical Oxygen Demand (BOD), Nitrate, Nitrite and Most Probable Number (MPN) increases, DO decreases progressively and Temperature and pH remain same. Conclusion: As far as quality of water with regard to recreational and industrial purposes are concerned, Ganges water may be considered useful but most of the parameters observed across different seasons indicates that it may not be used as potable water.

Urban rail departure capacity analysis based on a cellular automaton model**Project supported by the National Natural Science Foundation of China (Grant No. U1434207).

As an important traffic mode, urban rail transit is constantly developing toward improvement in service capacity and quality. When an urban rail transit system is evaluated in terms of its service capacity, the train departure capacity is an important index that can objectively reflect the service level of an urban rail transit facility. In light of the existing cellular automaton models, this paper proposes a suitable cellular automaton model to analyze the train departure capacity of urban rail transit under different variable factors and conditions. The established model can demonstrate the train operating processes by implementing the proposed sound rules, including the rules of train departure at the origin and intermediate stations, and the velocity and position updating rules. The properties of train traffic are analyzed via numerical experiments. The numerical results show that the departure capacity is negatively affected by the train departure control manner. In addition, (i) the real-time signal control can offer a higher train service frequency; (ii) the departure capacity gradually rises with the decrease in the line design speed to a limited extent; (iii) the departure capacity decreases with extension in the train length; (iv) the number of departed trains decreases as the train stop time increases; (v) the departure capacity is not affected by the section length. However, the longer the length, the worse the service quality of the urban rail transit line. The experiments show that the proposed cellular automaton model can be used to analyze the train service capacity of an urban rail transit system by performing quantitative analysis under various considered factors, conditions, and management modes.

Impact of Macrofaunal Communities on the Coastal Filter Function in the Bay of Gdansk, Baltic Sea

Abstract During three cruises to the Bay of Gdansk, Baltic Sea, the fauna, porewater and bottom water were sampled at stations parallel to the shore and along a transect offshore. Diffusive porewater fluxes were calculated and related to the total net fluxes (TNF) of nutrients. The TNF comprise all nutrients that reach the bottom water from the sediment including diffusive nutrient efflux, discharge from macrozoobenthos and microbial activity. They were determined during in situ incubations using a benthic chamber lander, which is rarely done in coastal research. The lander restricts the physical influence of currents and waves on the sediments and only allows nutrient fluxes due to bioturbation by natural communities. Strong benthic-pelagic coupling in the shallow coastal zone suggested a crucial filter function for the bioturbated coastal sediments, which are separated from muddy deep sediments with little or no fauna at a depth of 50 m; in between is a small intermediate zone. While diffusive fluxes were highest at intermediate and offshore stations, TNF were highest at sandy coastal stations, where reservoirs of dissolved nutrients were small and sediments almost devoid of organic material. The greatest impact of macrofauna on sedimentary fluxes was found at stations whose communities were dominated by deep-burrowing polychaetes. The largest TNF were measured directly at the mouth of the Vistula River, where riverine food and nutrients supplies were highest. Macrofauna communities and sediment variables can thus serve as descriptive indicator to estimate the extent of the coastal filter. Finally, based on the total areal size of the different sediment types, annual efflux for the complete coastal zone of the Gdansk Bay was estimated to be 6.9 kt N, 19 kt Si, and 0.9 kt P. Compared to the muddy offshore area, which is twice as large, these amounts were similar for P and threefold higher for N and Si.

A probabilistic design approach for load of metro tunnel induced by surrounding development: Part A: Determination of development intensity

Adjacent development causes metro tunnel problems in soft-soil areas. A mathematical framework based on conventional integration and probabilistic method is purposed to include development-induced external loads into a metro tunnel design. In this framework, the development-induced load on the tunnel is a convolution of development intensity on the load-transfer functions over the adjacent area of the metro line. The development intensity is related to the urban development pattern, which is gathered by using categorized statistics. The load transfer functions adopt analytical solutions and empirical equations describing construction impacts on surrounding soil or structures. Monte Carlo simulations are used to generate the development impact, i.e., the load and displacement, on the basis of which the design value under a certain reliability index can be obtained. Therefore, determination of the development-induced load is divided into two stages. Part A of the paper introduces a statistical description of the development intensity of a location. Street blocks and metro stations are qualitatively cataloged with respect to development trends, periods, and frequencies. Maps, satellite photos, and street views are used to collect data in three Chinese cities: Shanghai, Guangzhou, and Nanjing. For each city, samples include the central station in the new district, and the central station, grouping station, and intermediate station in the built-up areas. In addition, residential districts inside and outside the inner ring in Shanghai are analyzed. The distribution of the building heights and stories with distance, the proportion of urban renewal with time, and the areas/depths/shapes of the excavations are obtained. The development patterns of blocks surrounding the metro line and the residential areas are analyzed. These data become input descriptions of development intensities in Monte Carlo simulations. Part B of the paper introduces the load transfer functions and the generation of loads on the tunnel.

CALIBRATION AND VALIDATION OF THE SWAT HYDROLOGICAL MODEL FOR THE MUCURI RIVER BASIN

ABSTRACT Hydrological models are becoming more and more widespread, mainly due to their capacity to simulate the impact of environmental changes on water resources. In this way, the aim of this study was to calibrate and validate the SWAT model for the soil and climatic conditions of the Mucuri River Basin, located in the Northeast region of the States of Minas Gerais, Brazil. The SWAT-CUP software module SUFI2 was used to analyze the sensitivity, calibration and validation of the model. The calibration was performed in an intermediate fluviometric station and the validation in five other located: three upstream, one downstream and one independent from the calibration point. It was evidenced for the study area that the parameters referring to the basic flow processes were more sensitive. The model obtained a good adjustment with an overestimate tendency of 15%. In general, the SWAT model, using SWAT-CUP was good and adequate in terms of its calibration performance and validation of the flow simulation in the Mucuri River Basin by the determination coefficients, Nash-Suttclife efficiency and percentage of trend.