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NOVEL ACCESSIBILITY METRICS BASED ON HIERARCHICAL DECOMPOSITION OF TRANSPORT NETWORKS 一种新的基于传输网络层次分解的可达性度量
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2023-03-01 DOI: 10.20858/sjsutst.2023.118.10
Divya Kwatra, K. Rao, Vasudha Bhatnagar
Scientific analysis of public transport systems at the urban, regional, and national levels is vital in this contemporary, highly connected world. Quantifying the accessibility of nodes (locations) in a transport network is considered a holistic measure of transportation and land use and an important research area. In recent years, complex networks have been employed for modeling and analyzing the topology of transport systems and services networks. However, the design of network hierarchy-based accessibility measures has not been fully explored in transport research. Thus, we propose a set of three novel accessibility metrics based on the k-core decomposition of the transport network. Core-based accessibility metrics leverage the network topology by eliciting the hierarchy while accommodating variations like travel cost, travel time, distance, and frequency of service as edge weights. The proposed metrics quantify the accessibility of nodes at different geographical scales, ranging from local to global. We use these metrics to compute the accessibility of geographical locations connected by air transport services in India. Finally, we show that the measures are responsive to changes in the topology of the transport network by analyzing the changes in accessibility for the domestic air services network for both pre-covid and post-covid times.
在这个高度互联的当代世界,对城市、地区和国家层面的公共交通系统进行科学分析至关重要。量化交通网络中节点(位置)的可达性被认为是衡量交通和土地利用的整体指标,也是一个重要的研究领域。近年来,复杂网络已被用于建模和分析运输系统和服务网络的拓扑结构。然而,在交通研究中,基于网络层次结构的可达性措施的设计尚未得到充分探索。因此,我们提出了一组基于传输网络的k核分解的三种新的可达性度量。基于核心的可访问性指标通过引出层次结构来利用网络拓扑,同时将旅行成本、旅行时间、距离和服务频率等变化作为边缘权重。所提出的度量量化了从局部到全局的不同地理尺度上节点的可访问性。我们使用这些指标来计算印度航空运输服务连接的地理位置的可达性。最后,我们通过分析新冠疫情前和新冠疫情后国内航空服务网络可达性的变化,表明这些措施对运输网络拓扑结构的变化做出了反应。
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引用次数: 0
AN APPROACH TO RELIABILITY ANALYSIS OF AIRCRAFT SYSTEMS FOR A SMALL DATASET 基于小数据集的飞机系统可靠性分析方法
Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2023-03-01 DOI: 10.20858/sjsutst.2023.118.14
Onyedikachi Chioma OKORO, Maksym ZALISKYI, Dmytriiev SERHII, Ibinabo ABULE
Data-driven predictive aircraft maintenance approach typically results in lower maintenance costs, avoiding unnecessary preventive maintenance actions and reducing unexpected failures. Information provided by a reliability analysis of aircraft components and systems can improve an existing maintenance strategy and ensure an optimal maintenance task interval. For reliability work, the exponential distribution is typically used; however, this approach requires substantial amounts of data, which often may not be generated by aviation operations. Therefore, this study proposes a method for reliability analysis given a small dataset. Real-life historical data of an aircraft operating in Nigeria validate the proposed approach and prove its applicability.
数据驱动的预测性飞机维护方法通常可以降低维护成本,避免不必要的预防性维护行动,减少意外故障。飞机部件和系统的可靠性分析提供的信息可以改进现有的维修策略,并确保最佳的维修任务间隔。对于可靠性工作,通常采用指数分布;然而,这种方法需要大量的数据,而这些数据往往不是由航空业务产生的。因此,本研究提出了一种基于小数据集的可靠性分析方法。在尼日利亚运行的一架飞机的真实历史数据验证了所提出的方法并证明了其适用性。
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引用次数: 1
NUMERICAL INVESTIGATIONS ON THE DYNAMIC BEHAVIOUR OF A 2-DOF AIRFOIL WITH APPLICATION IN ENERGY HARVESTING SYSTEM 二自由度翼型动力特性数值研究及其在能量收集系统中的应用
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2023-03-01 DOI: 10.20858/sjsutst.2023.118.6
T. Haniszewski, D. Gąska, J. Margielewicz, T. Opasiak
This article presents the basic airfoil model with two degrees of freedom - the semi-rigid model, where its forced vibrations were considered, and the exciting force is the aerodynamic force, including its periodic changes, that is, gusts. Since the phenomenological model under study has a coupled form, its versions after decoupling are presented, which has an impact on the results of the final research. The airfoil model presented in this way was shown from the application side in the system of a simple energy harvester based on a deformable beam with piezoelectric elements. The result of the simulation tests is a preliminary analysis of the possibility of using the airfoil as a vibration generator for the energy harvesting system. Along with the application of the mechanical part, a numerical simulation of the electrical part was also implemented, related to the transformation of the voltage generated by piezoelectric elements into a constant voltage signal with a connected receiver with power consumption similar to the Atmega microcontroller with battery charging.
本文提出了具有两个自由度的基本翼型模型——半刚性模型,其中考虑了其强迫振动,激振力是气动力,包括其周期性变化,即阵风。由于所研究的现象学模型具有耦合形式,因此给出了解耦后的版本,这对最终研究的结果产生了影响。在基于带压电元件的可变形梁的简单能量采集器系统中,从应用端展示了以这种方式提出的翼型模型。模拟试验的结果是对使用翼型作为能量收集系统的振动发生器的可能性的初步分析。随着机械部分的应用,还对电气部分进行了数值模拟,将压电元件产生的电压转换为恒压信号,连接的接收器具有类似于带电池充电的Atmega微控制器的功耗。
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引用次数: 0
THE ANALYSIS OF WORK SHIFT PATTERNS AND RISK OF FATIGUE IN AIRCRAFT MAINTENANCE PERSONNEL: A CASE STUDY 飞机维修人员轮班模式与疲劳风险分析:个案研究
Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2023-03-01 DOI: 10.20858/sjsutst.2023.118.1
Fransisca Tiur BASARIA
In response to the COVID-19 pandemic in 2020, PT. XYZ, the biggest aircraft maintenance, repair, and overhaul (MRO) company in Indonesia, implemented a new shift pattern for line-maintenance personnel. The new shift pattern allows maintenance personnel to have fewer working hours per day (7-hour shifts) in more shift varieties for 5 consecutive days. Maintenance personnel will have 2-morning shifts, 1-noon shift, and 2-night shifts followed by 3 rest days. This study aims to explore the risk of fatigue caused by the newly implemented shift pattern. Data were collected through electronic questionnaires from a total of 303 respondents. This study found that at the time of the survey, many respondents (78 of 303, 26%) felt tired and had difficulty concentrating, regardless of the shift they were in. Based on the duty time, the highest scores of level 6 (tired, difficult to concentrate) were discovered on night shift day 5. This result shows that although the organization had provided the maintenance personnel with the opportunity to obtain sleep during rest days, tiredness and fatigue were still experienced by the aircraft maintenance personnel. This study recommends necessary actions to be taken to prevent fatigue, especially from the noon shift afterwards, where fatigue level is increasing, and alertness level is decreasing.
为应对2020年新冠肺炎疫情,印尼最大的飞机维护、维修和大修(MRO)公司PT. XYZ对线路维护人员实施了新的轮班模式。新的轮班模式允许维修人员每天工作时间更少(7小时一班),轮班品种更多,连续5天。维修人员有2个早班,1个中班,2个夜班,休息3天。本研究旨在探讨新实施的轮班模式所带来的疲劳风险。数据是通过电子问卷收集的,共有303名受访者。这项研究发现,在调查时,许多受访者(303人中有78人,占26%)感到疲倦,难以集中注意力,无论他们是在轮班。从值班时间来看,第6级(疲劳、难以集中注意力)得分最高的是夜班第5天。这一结果表明,虽然组织在休息日为维修人员提供了获得睡眠的机会,但飞机维修人员仍然会感到疲劳和疲劳。本研究建议采取必要的措施防止疲劳,特别是从中午班之后,疲劳程度增加,警觉性水平下降。
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引用次数: 0
NEW DESIGNS OF VARIABLE STIFFNESS COUPLINGS 变刚度联轴器的新设计
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2022-12-01 DOI: 10.20858/sjsutst.2022.117.6
P. Kaššay, M. Urbanský
Flexible couplings are widely used in mechanical drives of transport and other machines. A fundamental function of flexible shaft couplings regarding torsional vibration is the optimum tuning of torsional oscillating mechanical systems. At the authors’ workplace, the focus is on the research and design of pneumatic couplings, where the torque is transmitted mainly by compressed gas (air) in their pneumatic flexible elements. The primary advantage of these couplings is that their mechanical properties can be quickly and effectively adjusted, especially the dynamic torsional stiffness, by air pressure change directly while the mechanical system is running. This allows us “to tune” the properties of the pneumatic coupling according to the current parameters of the machine drive to avoid resonance and minimize torsional vibration. Therefore, we tend to refer to them as “pneumatic tuners of torsional vibration”. This paper aims to present two new types of these “pneumatic tuners” that were recently granted patent protections, namely “Pneumatic flexible shaft coupling with hose flexible element” and “Drum pneumatic flexible shaft coupling”. Because these pneumatic tuners are not in practical use yet, this paper describes only their design and supposed benefits.
柔性联轴器广泛应用于运输和其他机器的机械传动中。挠性联轴器关于扭转振动的一个基本功能是对扭转振荡机械系统进行最佳调谐。在作者的工作场所,重点是气动联轴器的研究和设计,其中扭矩主要通过其气动柔性元件中的压缩气体(空气)传输。这些联轴器的主要优点是,在机械系统运行时,通过直接改变空气压力,可以快速有效地调整其机械性能,尤其是动态扭转刚度。这使我们能够根据机器驱动的当前参数“调整”气动联轴器的特性,以避免共振并最大限度地减少扭转振动。因此,我们倾向于将它们称为“扭转振动的气动调谐器”。本文旨在介绍最近获得专利保护的两种新型“气动调谐器”,即“带软管柔性元件的气动柔性联轴器”和“滚筒气动柔性轴联轴器”。由于这些气动调谐器尚未投入实际使用,本文仅介绍了它们的设计和假定的优点。
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引用次数: 0
ANALYSIS OF MICRO-ELECTROMECHANICAL INERTIAL MEASUREMENT UNITS FOR UNMANNED AERIAL VEHICLE APPLICATIONS 用于无人机的微机电惯性测量装置分析
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2022-12-01 DOI: 10.20858/sjsutst.2022.117.9
A. Mammadov
Typically, an inertial navigation system (INS) is used to determine the position, speed, and orientation of an object moving relative to the earth's surface. The navigation information (position, speed and orientation) of an unmanned aerial vehicle (UAV) is needed to control its flight. Since the resistance of INS to interferences is very high, it is possible to ensure reliable flights in conditions of high-intensity noise. This article explores the principles of constructing inertial measurement units (IMU) that are part of the INS and indicates perspective directions for their development. Micro-electromechanical inertial measurement units were studied in this work, and functional and principal electrical circuits for connecting units of inertial measurements to the microcontroller were developed. The results of practical measurements of units without calibration and after calibration were obtained using the created laboratory device. Based on the obtained results, the necessity of sensor calibration was revealed, and accuracy was improved by performing calibration with the Kalman filter algorithm. The Kalman filter is the heart of the navigation system. In a low-cost system, IMU errors like bias, scale factor error and random walk noise dominate the INS error growth.
通常,惯性导航系统(INS)用于确定物体相对于地球表面移动的位置、速度和方向。无人机的导航信息(位置、速度和方向)是控制其飞行所必需的。由于惯性导航系统对干扰的抵抗力非常高,因此可以确保在高强度噪声条件下的可靠飞行。本文探讨了作为惯性导航系统一部分的惯性测量单元(IMU)的构建原理,并指出了其发展方向。本文研究了微机电惯性测量单元,并开发了将惯性测量单元连接到微控制器的功能电路和主要电路。使用创建的实验室设备获得了未校准和校准后单元的实际测量结果。基于所获得的结果,揭示了传感器校准的必要性,并通过使用卡尔曼滤波算法进行校准来提高精度。卡尔曼滤波器是导航系统的核心。在低成本系统中,IMU误差(如偏置、比例因子误差和随机游动噪声)主导了INS误差的增长。
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引用次数: 0
MODELLING THE VARIATION IN THE MOBILITY PATTERN OF HOUSEHOLDS IN THE URBAN AND RURAL AREAS OF NIGERIA 模拟尼日利亚城市和农村地区家庭流动模式的变化
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2022-12-01 DOI: 10.20858/sjsutst.2022.117.1
Oluwayemi-Oniya Aderibigbe, T. Gumbo
There is evidence that rural areas are disadvantaged in mobility compared to urban areas. Hence, this study examined spatial variation in the travel pattern of households in urban and rural areas of Nigeria. This study used primary data obtained through questionnaire administration on household heads in the residential zones of both urban and rural areas studied, using the multi-stage sampling technique. Findings revealed that variations exist for age, education level, income level, and occupation in urban and rural areas, and household's average daily mean trip frequency showed a level of fewer trips being generated in the rural area than those in the urban area. Furthermore, the result of the stepwise multiple regression analysis showed that transport mode, household size, number of workers in the house, and occupation of household head were significant variables influencing trip making in urban areas while age, household size, the income of household head and number of employed people were significant in the rural areas. This study concludes that differences exist in the mobility pattern of urban and rural households, and as such, equal consideration and attention should be given to them in policy formulations.
有证据表明,与城市地区相比,农村地区在流动性方面处于不利地位。因此,本研究考察了尼日利亚城市和农村地区家庭旅行模式的空间差异。本研究采用多阶段抽样技术,通过对城市和农村居住小区户主进行问卷调查获得的原始数据。调查结果显示,城乡居民在年龄、教育程度、收入水平和职业等方面存在差异,家庭日均出行频次显示农村居民的出行次数低于城市居民。逐步多元回归分析结果显示,交通方式、家庭规模、户主人数和职业是影响城市居民出行的显著变量,而年龄、家庭规模、户主收入和就业人数是影响农村居民出行的显著变量。本研究认为,城乡家庭流动模式存在差异,在制定政策时应予以同等考虑和重视。
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引用次数: 0
ANALYSIS OF ADVANCED TECHNOLOGY FOR COMBUSTION OF HOMOGENEOUS FUEL MIXTURE 均质燃料混合气燃烧先进技术分析
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2022-12-01 DOI: 10.20858/sjsutst.2022.117.14
M. Puškár, Matúš Lavčák, M. Šoltésová, M. Kopas
The most serious problems to overcome for a successful operation of the HCCI engine are control of the combustion phase, limited operational range, cold start of engine and high noise level during engine operation. This study aims at describing the engine power output characteristics and emission characteristics of HCCI engines under different testing conditions and the various challenges associated with these engines. Furthermore, this study holds a potential guide for overcoming these challenges and improvement of the engine power output as well as the emission characteristics. Thus, it is possible to say, concerning the performed investigation work, that HCCI combustion can be applied in existing conventional engines after their modifications. The most significant result of the HCCI process application is the reduction of NOx emissions and soot emissions, keeping almost the same engine power output as the conventional combustion process.
HCCI发动机成功运行需要克服的最严重的问题是燃烧阶段的控制、有限的运行范围、发动机的冷启动和发动机运行期间的高噪声水平。本研究旨在描述HCCI发动机在不同测试条件下的发动机功率输出特性和排放特性,以及与这些发动机相关的各种挑战。此外,这项研究为克服这些挑战、提高发动机功率输出和排放特性提供了潜在的指导。因此,就所进行的研究工作而言,可以说HCCI燃烧在现有的传统发动机中经过改进后可以应用。HCCI工艺应用的最重要结果是减少了NOx排放和烟尘排放,保持了与传统燃烧工艺几乎相同的发动机功率输出。
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引用次数: 1
DECISION SUPPORT FOR CHOOSING A SCENARIO FOR ORGANIZING URBAN TRANSPORT SYSTEM WITH SHARE OF ELECTRIC VEHICLES 电动汽车共享城市交通系统方案选择的决策支持
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2022-12-01 DOI: 10.20858/sjsutst.2022.117.5
M. Jacyna, R. Żochowska, A. Sobota, M. Wasiak
This article presents the issue of using decision support tools to select the variant of organization of urban transport system. Two scenarios for the use of electric vehicles were compared, considering not only their emissions and fuel consumption but also the limited accessibility of conventional vehicles to the city. The authors assume that the development of urban traffic organization must go hand in hand with the challenges of planning sustainable urban mobility and reducing harmful exhaust fumes. Furthermore, decision-makers should be equipped with simple decision support tools to generate the best option considering the expectations of transport users. The PTV VISUM tool was used to analyse and visualize two different organization scenarios for a selected city in Poland.
本文提出了使用决策支持工具来选择城市交通系统组织的变体的问题。对电动汽车的两种使用场景进行了比较,不仅考虑了它们的排放和燃料消耗,还考虑了传统汽车进入城市的可能性有限。作者认为,城市交通组织的发展必须与规划可持续城市交通和减少有害废气的挑战齐头并进。此外,决策者应配备简单的决策支持工具,以在考虑交通用户期望的情况下产生最佳选择。PTV VISUM工具用于分析和可视化波兰选定城市的两种不同组织场景。
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引用次数: 0
SCHWECHAT AIRPORT DEVELOPMENT FORECAST AS A RISK MANAGEMENT TOOL TO ADDRESS THE IMPACT OF THE COVID-19 PANDEMIC 施微信机场发展预测作为应对COVID-19大流行影响的风险管理工具
IF 0.6 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY Pub Date : 2022-12-01 DOI: 10.20858/sjsutst.2022.117.15
R. Rozenberg, Marek Tomas, A. Tobisová, P. Hanák
The COVID-19 pandemic has affected all areas of our society. The effects of the pandemic on the economy have not only affected mainly the development of transport and tourism but most especially air transport. Many airports in Europe and around the world have experienced a drop in passengers and cargo due to the COVID-19 pandemic. For many airports, this period, which began in 2019, meant huge losses due to a drop in passengers, leading to the collapse of several airlines. Despite the gradually improving situation, the impact of the pandemic is still being felt, and the number of passengers at airports is growing rather slowly. Thus, airports had to deal with the current situation and adapt their future operation to the current conditions. Even the leading airport in Central Europe - the Schwechat Airport in Vienna - was not spared from the effects of the current pandemic. This article aims to evaluate the effects of the COVID-19 pandemic on Schwechat airport. It focuses on the analysis of the development of the airport before and during the pandemic up to the present. Further, this article describes the problems that Schwechat airport dealt with throughout the period, with the loss of passengers, delays and the collapse of carriers. Subsequently, this article is part of a study aimed at identifying the negative effects of the pandemic on air transport and related industries worldwide. Predicting the development of the airport is a very important aspect, especially for the company's management and should be part of the risk management of every company.
COVID-19大流行影响了我们社会的各个领域。这一大流行病对经济的影响不仅主要影响到运输和旅游业的发展,而且尤其影响到航空运输。由于新冠肺炎大流行,欧洲和世界各地的许多机场的客运量和货运量都出现了下降。对于许多机场来说,这段从2019年开始的时期意味着由于乘客减少而造成的巨大损失,导致几家航空公司倒闭。尽管情况逐渐改善,但仍能感受到大流行的影响,机场的旅客人数增长相当缓慢。因此,机场必须应对当前的情况,并使其未来的运营适应当前的条件。即使是中欧的主要机场——维也纳的施微信机场——也未能幸免于当前大流行病的影响。本文旨在评价新冠肺炎疫情对施微信机场的影响。它侧重于分析机场在大流行之前和期间直至目前的发展情况。此外,本文还描述了施微信机场在整个时期所面临的问题,包括乘客损失、延误和航空公司倒闭。随后,本文是一项研究的一部分,旨在确定大流行对全球航空运输和相关行业的负面影响。预测机场的发展是一个非常重要的方面,特别是对公司的管理,应该是每个公司的风险管理的一部分。
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引用次数: 0
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