scholarly journals Analytical Optimization Model to Locate and Design Runway-Taxiway Junctions

2021 ◽  
Vol 15 (1) ◽  
pp. 347-359
Author(s):  
Misagh Ketabdari ◽  
Ignacio P. Millán ◽  
Emanuele Toraldo ◽  
Maurizio Crispino ◽  
Mariano Pernetti
Keyword(s):  
Degrees Of Freedom ◽  
Operating Costs ◽  
Design Solution ◽  
Field Range ◽  
Main Research ◽  
Research Areas ◽  
Operation Costs ◽  
The Mean ◽  
Statistical Risk

Aims: Air traffic and airport operations are expected to experience significant growth worldwide in the upcoming years. One of the possible approaches to adapt to this demand-led growth in the sector, while guaranteeing optimal levels of airport services and operations safety, is to maximize the capacities of busy airport infrastructures (in particular runways) by evacuating them in the shortest time possible to be ready for hosting next operations. Background: The main research areas in this field range from statistical risk analyses based on the registered accidents databases to simulation analyses modelling the behaviour of the aircraft during landing operations. Objective: The main objective of this study is to determine precisely the optimal distances of runway-taxiway junctions from the runway’s threshold, according to numerous impact parameters such as airport climate pattern, operating aircraft categories, infrastructure type, and capacity, route connections, operating costs, and associated risks. Methods: The authors developed a mathematical model with the goal of simulating the dynamic behaviour of the aircraft during landing and possible consequences introduced by the presence of contaminants over the pavement surface, by calculating their braking distances, and finally to optimize the use of existing infrastructures, specially runway-taxiway junctions, of a commercial airport. In this regard, the interactions between landing gear, pavement, and fluid were carefully analysed. The dynamic pavement skid resistance values in wet pavement conditions were evaluated for optimizing the required landing distances, which are setting the base for optimizing the location of the taxiway junctions. An Italian international airport was selected as the case study to be simulated by the developed model in order to optimize its runway capacity and maximize its rate of operations. Results: In the process, two different scenarios are simulated with the developed model; a modified design of an existing runway and an alternative design solution for constructing a new runway. The developed model offers improvements for both scenarios with respect to the current runway configurations in terms of reduction in mean rolling distances. The simulation of the selected case study shows that the taxiway modification scenario achieves a reduction of 23% in the mean rolling distance for wet and 25% for dry pavement conditions. While, for designing a new runway, greater reductions of 27% for wet and 39% for dry pavement conditions are obtained due to the higher flexibilities and degrees of freedom in designing a runway from the beginning. Conclusion: The developed model can precisely propose new configurations of the runway-taxiway junctions with lower mean rolling distances, which lower the operation costs and fuel consumption, decrease the runway evacuation times and increase the capacity of the airfield. The main advantage of this model is its ability to cover a wider spectrum of boundary conditions with respect to the existing models and its applicability for designing new runways, plus to optimize the configuration of existing infrastructures in order to satisfy the evolution of the industry.

scholarly journals Interpretation of soil erosion in a Polish loess area using OSL, 137Cs, 210Pbex, dendrochronology and micromorphology – case study: Biedrzykowice site (s Poland)

2019 ◽  
Vol 46 (1) ◽  
pp. 57-78 ◽  
Author(s):  
Grzegorz Poręba ◽  
Zbigniew Śnieszko ◽  
Piotr Moska ◽  
Przemysław Mroczek ◽  
Ireneusz Malik
Keyword(s):  
World War Ii ◽  
Soil Erosion ◽  
Middle Ages ◽  
Agricultural Field ◽  
World War ◽  
Field Range ◽  
Loess Area ◽  
Erosion Processes ◽  
The Mean

Abstract Loess areas used for agriculture are susceptible to soil erosion. The intensive process of soil erosion in Polish loess areas began with the onset of the Neolithic and has continued intermittently until today. This work presents the results of soil erosion from simultaneous use of the 137Cs and 210Pbex methods on an agricultural field located on loess slope. Moreover, to establish the age of accumulated sediment connected with water slope erosion, OSL dating, selected physicochemical and micromorphological analyses were applied. The reference values of the 137Cs and 210Pbex fallout for the studied site (Biedrzykowice, the Proszowice Plateau, Małopolska Upland) equal 2627 (45% connected with Chernobyl) and 4835 Bq·m–2, respectively. The results of the 137Cs and 210Pbex inventories measured for the agricultural field range from 730 to 7911 and from 1615 to 11136 Bq·m–2, respectively. The mean soil erosion is about 2.1 kg·m–2·a–1 (about 1.4 mm·a–1). The accumulation of the colluvial sediments started in the Neolithic and drastically increased in the Middle Ages. The examined gully catchment in Biedrzykowice has probably developed quite rapidly as a result of increased erosion. This resulted in the abandonment of this area as farmland and, consequently, in the minimization of water erosion on the slope due to the entrance of woody vegetation in this area. Erosion processes were highly intensified during the last 70 years as a result of deforestation after World War II and intensive agricultural reuse of this area after a break, as indicated by isotope measurements and dendrochronology.

scholarly journals Unmanned Aerial Vehicles enabled IoT Platform for Disaster Management

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2706 ◽  
Author(s):  
Waleed Ejaz ◽  
Muhammad Awais Azam ◽  
Salman Saadat ◽  
Farkhund Iqbal ◽  
Abdul Hanan
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Disaster Management ◽  
Future Research ◽  
Wildfire Management ◽  
Holistic View ◽  
Main Research ◽  
Research Areas ◽  
Aerial Vehicles ◽  
Iot Platform

Efficient and reliable systems are required to detect and monitor disasters such as wildfires as well as to notify the people in the disaster-affected areas. Internet of Things (IoT) is the key paradigm that can address the multitude problems related to disaster management. In addition, an unmanned aerial vehicles (UAVs)-enabled IoT platform connected via cellular network can further enhance the robustness of the disaster management system. The UAV-enabled IoT platform is based on three main research areas: (i) ground IoT network; (ii) communication technologies for ground and aerial connectivity; and (iii) data analytics. In this paper, we provide a holistic view of a UAVs-enabled IoT platform which can provide ubiquitous connectivity to both aerial and ground users in challenging environments such as wildfire management. We then highlight key challenges for the design of an efficient and reliable IoT platform. We detail a case study targeting the design of an efficient ground IoT network that can detect and monitor fire and send notifications to people using named data networking (NDN) architecture. The use of NDN architecture in a sensor network for IoT integrates pull-based communication to enable reliable and efficient message dissemination in the network and to notify the users as soon as possible in case of disastrous situations. The results of the case study show the enormous impact on the performance of IoT platform for wildfire management. Lastly, we draw the conclusion and outline future research directions in this field.

Public-Private Interactions in Anglo-Greek Tourism: Reflections on Aspects of the Primary Research Process

2003 ◽  
Vol 4 (4) ◽  
pp. 321-330 ◽  
Author(s):  
Georgios Papageorglou
Keyword(s):  
Research Process ◽  
Thought Process ◽  
Primary Research ◽  
Main Research ◽  
Research Areas ◽  
Ongoing Work ◽  
Accommodation Sector ◽  
Methodological Considerations ◽  
The Uk

The issues discussed in this paper stem from the author's ongoing work in the field of tourism. The main research areas are the relationships between tour operators, the accommodation sector and National Tourism Offices with an emphasis on marketing and promotion, as well as the influence of external factors on the effectiveness of promotional activities. The connections, along these lines, between the UK and Greece are examined in a case study. The paper will illustrate the thought process underpinning the primary research for the study. Its aim is to highlight and analyse a number of methodological considerations and conscious decisions that had to be made during its course, while emphasis is given to the issues revolving around the preparation and implementation of primary research.

NON-DEMOCRATIC POLITICAL REGIMES - MAIN VECTORS OF TRANSFORMATION

2021 ◽  
Vol 66 (1) ◽  
pp. 101-106
Author(s):  
ANTON V. GRISHIN ◽  
Keyword(s):  
Political Regime ◽  
Gradual Change ◽  
Political Regimes ◽  
Operational Model ◽  
Main Research ◽  
Research Areas ◽  
Democratic Regimes ◽  
Cross Country

The article proposes an operational model for comparative analysis of non-democratic political regimes. It is based on the holistic methodology, new institutionalism framework and structural-functional approach. The paper systematizes the theories of foreign and Russian authors towards typology and differentiation between certain types of autocracies. There is a tendency to gradual change in the main research areas in the community of transitology scholars - from “democratic optimism” witnessed at the end of the twentieth century to the analysis of the mechanisms of self-preservation of autocracies, which has gained popularity in recent years. The essence of the "political regime" concept is specified with regard to its static and dynamic aspects. Some differences between democratic and non-democratic regimes are considered. The article explores basic typologies of political regimes, enumerates the characteristics of some types of non-democratic political regimes, and proposes relevant operational definitions. Main vectors of transformations of autocracies, such as liberalization or strengthening of authoritarian tendencies, are indicated. Both of them can be considered either as actions taken so as to preserve the authoritarian system or promote democratization. The operational model elaborated in this paper for the classification of non-democratic political regimes and their transformations can be used to conduct cross-country, as well as cross-temporal comparisons within the framework of case study.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

Social exchange processes, health behaviour, and health behaviour change

2008 ◽  
Vol 16 (3) ◽  
pp. 131-134
Author(s):  
Urte Scholz ◽  
Rainer Hornung
Keyword(s):  
Social Exchange ◽  
Health Behaviour ◽  
Psychological Research ◽  
Smoking Behaviour ◽  
Self Report ◽  
Long Term Effects ◽  
Main Research ◽  
Research Areas ◽  
Exchange Processes ◽  
Multi Method Approach

Abstract. The main research areas of the Social and Health Psychology group at the Department of Psychology at the University of Zurich, Switzerland, are introduced. Exemplarily, three currently ongoing projects are described. The project ”Dyadic exchange processes in couples facing dementia” examines social exchanges in couples with the husband suffering from dementia and is based on Equity Theory. This project applies a multi-method approach by combining self-report with observational data. The ”Swiss Tobacco Monitoring System” (TMS) is a representative survey on smoking behaviour in Switzerland. Besides its survey character, the Swiss TMS also allows for testing psychological research questions on smoking with a representative sample. The project, ”Theory-based planning interventions for changing nutrition behaviour in overweight individuals”, elaborates on the concept of planning. More specifically, it is tested whether there is a critical amount of repetitions of a planning intervention (e.g., three or nine times) in order to ensure long-term effects.

Borders, Conflicts and Bargaining in Federations and Communities of Governments

2009 ◽  
pp. 83-99
Author(s):  
A. Libman
Keyword(s):  
Economic Policy ◽  
Public Authority ◽  
Modern World ◽  
Main Research ◽  
Research Areas ◽  
Nation States ◽  
Distribution Of Power

Economic policy in the modern world can be treated as an outcome of interaction of multiple territorial centers of public authority: nation-states, subnational and supranational jurisdictions. In the last decades economics has increased its attention to the factors which influence the distribution of power among jurisdictions. The paper surveys two main research areas in this literature: economics of conflicts and theory of endogenous decentralization. It discusses the basic models of both approaches and their modifications applied in the literature as well as factors of conflict formation and bargaining over devolution.

scholarly journals Hybrid Seven-bar Press Mechanism

2018 ◽  
Vol 12 (3) ◽  
pp. 181-187
Author(s):  
M. Erkan Kütük ◽  
L. Canan Dülger
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Design Optimization ◽  
Hybrid System ◽  
Degrees Of Freedom ◽  
Dimensional Synthesis ◽  
Design Variables ◽  
Optimization Study ◽  
Metal Stamping

An optimization study with kinetostatic analysis is performed on hybrid seven-bar press mechanism. This study is based on previous studies performed on planar hybrid seven-bar linkage. Dimensional synthesis is performed, and optimum link lengths for the mechanism are found. Optimization study is performed by using genetic algorithm (GA). Genetic Algorithm Toolbox is used with Optimization Toolbox in MATLAB®. The design variables and the constraints are used during design optimization. The objective function is determined and eight precision points are used. A seven-bar linkage system with two degrees of freedom is chosen as an example. Metal stamping operation with a dwell is taken as the case study. Having completed optimization, the kinetostatic analysis is performed. All forces on the links and the crank torques are calculated on the hybrid system with the optimized link lengths

Sign in / Sign up

Export Citation Format

Share Document