Iskanje po katalogu digitalne knjižnice

Opis: Present-day airline industry is quite a competitive field and crew scheduling represents one of the crucial problems due to significant impact on the airline's cost. The crew scheduling problem is based on the assignment of crew members to operate different tasks of route. The main goal of this paper is to provide an analysis and a solution to one of the biggest problems detected on a small airport in the Serbia - the problem of ground crew scheduling. The paper presents the main characteristics, goals and limitations of a real-life problem identified at this small airport. In order to solve the problem, we developed a dynamic discrete simulation model. The model is developed in a spreadsheet environment of Microsoft Excel. Some of the main limitations found in the development of the model are strong constraints and multiple goals. The model presented in the paper is designed as a useful management tool for smaller airports and is aimed at the improvement of operative processes.
Ključne besede: crew scheduling problem, modelling, air transport, small airport, management, spreadsheets
Objavljeno v DKUM: 01.10.2024; Ogledov: 0; Prenosov: 1
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Opis: Purpose: This paper aims to inform the promotion of sustainable modes of transport. For this purpose, it deploys a means-ends framework as a type of second-order cybernetics and uses it to explore cognitive transport mode choice structures. Design/methodology/approach: The empirical study relies on a purposive sample and a qualitative research methodology known as laddering. It is aimed at the identification and comparative analysis of the cognitive means-ends structures of transport users. Findings: The results reveal more positive and complex associations for the car than for public transport. Two main positive means-ends structures are identified for public transport, one related with the relaxation and the other with doing useful things while travelling. Dominant positive structures for the car are related with self-confidence, satisfaction and personal freedom. Negative means-ends structures in addition reveal important justifications and rationalizations for car use. Practical implications: Based on the identified distinct means-ends elements and structures, this study holds important implications for developing a communications strategy and policy interventions seeking to promote public transport. Originality/value: Means-ends theory is proposed as an integrative cybernetic framework for the study of stakeholders' (customers') mental models. The empirical study is the first to concurrently and comparatively examine positive and negative means-ends chains for the car and for the public transport modes.
Ključne besede: public transport, second-order cybernetics, laddering methodology, means-ends theory, private car, mental models, personal values, marketing, consumer
Objavljeno v DKUM: 27.08.2024; Ogledov: 93; Prenosov: 10
Celotno besedilo (692,92 KB)
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Opis: The greatest challenge of physically-challenged individuals is mobility, thereby making access to public transportation essential to independent living for these individuals. The study was conducted in Oyo State. Multistage sampling method comprising purposive and simple random sampling was used to select a sample size of 226 students from three special education centres in the state. Findings revealed that factors such as operators’ impatience/discrimination, waiting time and lack of assistance were major problems that affects accessibility to IPTs. Furthermore, results showed that difficulties experienced by the physically-challenged individuals differ significantly by the nature of disability as evidenced by a chi-square value of 37.218, p<0.05. It was therefore recommended that government should listen more to these transport disadvantaged people living with disabilities and integrate their concerns/suggestions in the design, implementation and monitoring of transport infrastructure and services as well as providing sustainable transport means to their transport challenges.
Ključne besede: accessibility, intermediate public transport (IPTs), transport disadvantaged, physically-challenged
Objavljeno v DKUM: 22.08.2024; Ogledov: 111; Prenosov: 3
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Opis: The manuscript discusses the investigation of vehicle flow in a predesignated junction byan appropriate traffic flow management with an effort to minimize fuel consumption, the productionof CO2, an essential greenhouse gas (hereinafter referred to as GHG), and related transport costs.The particular research study was undertaken in a frequented junction in the city of Celje, located in the eastern part of Slovenia. The results obtained summarize data on consumed fuel and produced CO2 amounts depending on the type of vehicle, traffic flow mixture, traffic light signal plan, andactual vehicle velocity. These values were calculated separately for three different conditions of traffic flow management. Amounts of fuel consumed were experimentally investigated in real traffic situations, whereas CO2 production was calculated by applying the actual European standardentitled EN 16258:2012 associated with a guideline for measuring emission values, as well as by examining specific traffic flow parameters. The key objective of the manuscript is to present multiple scenarios towards striving to minimize environmental impacts and improve transport operation's economic consequences when implementing proper traffic flow management. As for crucial findings, we quantified fuel consumption and CO2 emissions based on real data on the number and type of vehicles crossing the examined intersection and traffic light switching intervals. The results show that most of the CO2 was produced while waiting and in the accelerating phase in front of traffic lights, whereby in the running phase through the intersection, significantly less fuel was used. This study represents a mosaic fragment of research addressing endeavors to reduce CO2 production in urban transport. Following the experiments conducted, we can see a notable contribution towards reducing CO2 production with known and tested interventions in the existing transport infrastructure. A procedure embracing individual research steps may be deemed as an approach methodology dealing with traffic flow management with an aim to decrease the environmental and economic impacts oftraffic and transport operation; this is where the novelty of the research lies.
Ključne besede: traffic flow management, urban transport, CO2 production, greenhouse gas, fuel consumption, methodology, logistics, crossroads
Objavljeno v DKUM: 19.08.2024; Ogledov: 82; Prenosov: 5
Celotno besedilo (3,43 MB)
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Opis: As important as the classical approaches such as Akaike's AIC information and Bayesian BIC criterion in model-selection mechanism are, they have limitations. As an alternative, a novel modeling design encompasses a two-stage approach that integrates Fuzzy logic and Monte Carlo simulations (MCSs). In the first stage, an entire family of ARIMA model candidates with the corresponding information-based, residual-based, and statistical criteria is identified. In the second stage, the Mamdani fuzzy model (MFM) is used to uncover interrelationships hidden among previously obtained models criteria. To access the best forecasting model, the MCSs are also used for different settings of weights loaded on the fuzzy rules. The obtained model is developed to predict the road freight transport in Slovenia in the context of choosing the most appropriate electronic toll system. Results show that the mechanism works well when searching for the best model that provides a well-fit to the real data.
Ključne besede: forecasting road transport, electronic toll system, Monte Carlo simulation, ARIMA models, logistics
Objavljeno v DKUM: 11.06.2024; Ogledov: 135; Prenosov: 6
Celotno besedilo (2,36 MB)
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