scholarly journals Dynamic Model for Scheduling Crew Shifts

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Vojtech Graf ◽  
Dusan Teichmann ◽  
Jiri Horinka ◽  
Michal Dorda
Keyword(s):  
Mathematical Model ◽  
Decision Processes ◽  
Air Transport ◽  
Flight Schedules ◽  
Original Plan ◽  
Short Period ◽  
Operational Management ◽  
Additional Costs ◽  
Optimum Solution ◽  
Operations Center

In regular as well as nonscheduled air transport, extraordinary situations occasionally occur, which may fundamentally disrupt the flight schedule. Fundamental disruptions of flight schedules affect not only passengers but also the airline. One of the areas that are negatively affected by the disruption is the crew plan. Due to extraordinary events, it happens that a flight is delayed, and the crew will not be at the destination airport at the prescribed time and the airline will not be able to assign it on further flights according to the original plan. Such situations can be resolved either by deploying any other available crew or by delaying the flight appropriately until the previously planned crew is available. Assigning a new crew entails additional costs for the airline, as it has to assign more flight staff than had been originally planned. Furthermore, delayed flights lead to paying passengers financial compensation, incurring additional costs for airlines. Therefore, it is important that the airline is able to resolve any irregularity situations so that the additional costs incurred to deal with the irregularity situations are kept at a minimum. The paper presents one possible approach, a mathematical model that can be used to solve such a situation. The presented mathematical model may be the basis for the decision support system of the operations center worker who is responsible for the operational management of flight crews. The model will primarily aim at smaller airlines that cannot afford expensive software and often rely on manual solutions. However, a manual solution may not always be the best, as the operator, who plans the processes, may not consider all the constraints. Another important factor that makes the decision processes more difficult is that it is usually necessary to decide in a short period of time. The solution proposed in this paper will allow the operator to make a quick decision that will also be the most advantageous for the airline. This is because the proposed method is an exact approach, which guarantees finding the optimum solution. In this article, we are only dealing with pilot crews.

scholarly journals Determination of the Precise Coordinates of the GPS Reference Station in of a GBAS System in the Air Transport

2020 ◽  
Vol 22 (3) ◽  
pp. 11-18
Author(s):  
Kamil Krasuski ◽  
Stepan Savchuk
Keyword(s):  
Mathematical Model ◽  
Measurement Technique ◽  
Air Transport ◽  
Reference Station ◽  
The Real ◽  
Station Coordinates ◽  
Geocentric Coordinates

This paper presents results of research concerning determination of the GPS reference station coordinates located on the grounds of an EPDE airport in Deblin. The study uses a mathematical model of the PPP measurement technique in order to determine the coordinates of the reference station using the real GPS code-phase observations. The computations of the coordinates of the GPS reference station were carried out in numerical applications CSRS-PPP, APPS and GAPS. In this research was found that the accuracy of finding solutions to the XYZ geocentric coordinates of the reference station REF1 between solutions CSRS-PPP, APPS and GAPS ranges from 0.01m to 0.13m. In addition, the accuracy of determining the XYZ geocentric coordinates from the PPP method related to the GPS differential solution ranged from 0.01m to 0.11m.

A Hybrid Expert System–Nonlinear Programming Approach to Optimal Gear Design

1989 ◽  
Author(s):  
K.-C. Lin ◽  
G. E. Johnson
Keyword(s):  
Mathematical Model ◽  
Expert System ◽  
Spur Gear ◽  
Design Guidelines ◽  
Geometric Design ◽  
Geometric Constraints ◽  
Programming Approach ◽  
Gear Design ◽  
Design Variables ◽  
Short Period

Abstract An expert system is developed for optimal spur gear design. Design automation is accomplished by dividing the design variables into different categories, i.e. geometric design variables and non-geometric design variables. The geometric variables are further divided into terms that are related to the gear mathematical model and terms that are determined according to the designer’s experience. By properly developing the mathematical model, numerical optimisation can be used to seek the best solution for a given set of geometric constraints. The process of determining the non-geometric design variables is automated by using symbolic computation. This gear design expert system is built according to the AGMA standards and a survey of gear design experts. The recommendations of gear designers and the information provided by AGMA standards are integrated into knowledge bases and data bases. By providing fast information retrieval and design guidelines, this expert system greatly streamlines the spur gear design process and makes it possible for a novice designer to achieve a reliable design in a short period of time.

THE APPLICATION OF LINEAR PROGRAMMING IN NUTRITION AT THE CHILDREN’S HOME IN SLAVONSKI BROD

2004 ◽  
Vol 10 (3-4) ◽  
pp. 41-52
Author(s):  
Igor Brajdić ◽  
Josip Bogović
Keyword(s):  
Mathematical Model ◽  
Linear Programming ◽  
Simplex Method ◽  
Problem Formulation ◽  
Annual Saving ◽  
Actual Situation ◽  
Children's Home ◽  
Single Meal ◽  
Optimum Solution

The nutrition model belongs to a broader set o f problems known as mixture problems. In the literature, it is used as one of the typical examples of linear programming solved by the simplex method. It is of interest to investigate the possibilities of applying this model to an actual situation, such as the problem of nutrition at the Children’s Home in Slavonski Brod. Despite certain limitations to the simplex method, as well as limitations in problem formulation, in which the issue of tastes is neglected, by solving the assigned mathematical model for nutrition using the simplex method an optimum solution has been reached which meets all the conditions set forth in the formulation of the problem. The application of the model using the simplex method indicates a possible annual saving of 74,866 kunas per single meal. Results obtained could serve as guidelines in analysing the costs of the Children’s Home and in improving costs management by helping to determine the optimum financial schedule for nutrition. Benefits would include reducing the costs of nutrition and minimizing the wastage of food.

scholarly journals Comparison of Three Measures to Promote National Fitness in China by Mathematical Modeling

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Pan Tang ◽  
Daqing Xu ◽  
Qing Dai ◽  
Tingting Huang
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Physical Exercise ◽  
Three Dimensional ◽  
Chinese Government ◽  
Model Parameters ◽  
National Bureau ◽  
Short Period ◽  
Key Parameter

In this paper we established a mathematical model for national fitness in China. Based on a questionnaire and data of the General Administration of Sport of China and the National Bureau of Statistics of China, the dynamics for three classes of people are expressed by a system of three-dimensional ordinary equations. Model parameters are estimated from the data. This study indicated that national fitness put out by the Chinese government is reasonable. By finding the key parameter, the best measure to promote national fitness is put forward. In order to increase the number of people who frequently participate in sport exercise in a short period of time, if only one measure can be chosen, guiding people who never take part in physical exercise will be the best measure.

Research on Modeling of Screw Pump Characteristic Mathematical Model

2011 ◽  
Vol 361-363 ◽  
pp. 540-546
Author(s):  
Yun Ping Zheng ◽  
Yan Bin Yu ◽  
Yu Chun Wang ◽  
Xun Li ◽  
Jie Shu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Pressure Difference ◽  
Model Building ◽  
Pso Algorithm ◽  
Optimization Method ◽  
Design Quality ◽  
Screw Pump ◽  
Management Efficiency ◽  
Operational Management ◽  
Shaft Power

For the design and management of the modern heavy oil piplines, the application of mathematical model to describe the characteristics of screw pump is crucial to the improvement of design quality and operational management efficiency. According to the features of HOW7T.3(50mm) screw pump’s actual measured data, this research established two groups of mathematical model.The first one described the change of screw pump’s displacement along with the variation of pressure difference and viscosity, while the second group described the change of shaft power along with the variation of pressure difference and viscosity, and then it solved all the four models by a particle swarm optimization (PSO) algorithm. The model-building and model-solving of these two examples showed that the PSO algorithm could rapidly search the best model regression parameter. Through the four target test, the research finally selected two models with relatively high accuracy. In the end, the paper put forward that it is necessary to take further research on the forms of screw pump characteristic mathematical model, and the corresponding optimization method of model-solving, in order to make the models more succinct and with higher fitting precision.

scholarly journals The anatomy of the head and mouth parts of Psylla mali, the Apple sucker, with some remarks on the function of the labium

Parasitology ◽  
1919 ◽  
Vol 11 (3-4) ◽  
pp. 456-488 ◽  
Author(s):  
A. J. Grove
Keyword(s):  
Limited Time ◽  
Nervous Systems ◽  
Original Plan ◽  
Short Period ◽  
Adult Insect

The investigation, of which the results contained in this paper are a part, was first commenced in 1910. It was then proposed to describe in some detail the entire anatomy of the adult insect, but when a measure of progress had been made, and the alimentary, tracheal, and nervous systems had been almost completed, the work was interrupted by my taking up an appointment in India. On returning to England in 1915, the enquiry was resumed for a short period at the end of the year, but early in 1916 it had to be abandoned again to meet the superior claims of entomological work with the Forces in Mesopotamia, for the War Office. This, and other investigations connected with problems which have arisen in England in consequence of the War, prevented any further progress being made, but, with the declaration of the Armistice it was felt that attention might once more be given to it. In the limited time which could be devoted to the work, it has not been possible to carry out the original plan of including the whole anatomy in one paper, and the description of the head and mouth parts has been selected because of the somewhat novel considerations which have arisen in connection with the latter, particularly with regard to the function of the labium during the operation of piercing, the publication of which it seemed undesirable to delav further.

Design, modeling and simulation of a control surface-less tri-tilt-rotor UAV

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vinoth Kumar Annamalai ◽  
Selvakumaran Thunaipragasam
Keyword(s):  
Mathematical Model ◽  
Flight Control ◽  
Pid Controller ◽  
Control Model ◽  
Control Surface ◽  
Model Parameters ◽  
Content Type ◽  
Tilt Rotor ◽  
Short Period ◽  
Thrust Vector

Purpose The purpose of this study is to design a flight control model for a control surface-less (CSL) tri-tilt-rotor (TTR) unmanned aerial vehicle (UAV) based on a Proportional Integral Derivative (PID) controller to stabilize the altitude and attitude of the UAV subjected to various flying conditions. Design/methodology/approach First, the proposed UAV with a tilting mechanism is designed and analyzed to obtain the aerodynamic parameters. Second, the dynamics of the proposed UAV are mathematically modeled using Newton-Euler formation. Then, the PID controller is implemented in the simulation model to control flight maneuvers. The model parameters were implemented in a mathematical model to find the system’s stability for various flight conditions. The model was linearized to determine the PID gain values for vertical take-off and landing, cruise and transition mode. The PID controller was tuned to obtain the desired altitude and attitude in a short period. The tuned PID gain values were implemented in the PID controller and the model was simulated. Findings The main contribution of this study is the mathematical model and controller for a UAV without any control surface and uses only a thrust vector control mechanism which reduces the complexity of the controller. The simulation has been carried out for various flight conditions. The altitude PID controller and the attitude PID controller for CSL-TTR-UAV were tuned to obtain desired altitude and attitude within the optimum duration of 4 s and deviation in the attitude of 8%, which is within the allowable limit of 14%. The findings obtained from the simulation revels that the altitude and attitude control of the CSL-TTR-UAV was achieved by controlling the rpm of the rotor and tilt angle using the PID controller. Originality/value A novel CSL TTR UAV mathematical model is developed with a dual tilting mechanism for a tail rotor and single axis tilt for the rotors in the wing. The flight control model controls the UAV without a control surface using a PID controller for the thrust vector mechanism.

scholarly journals A simple mathematical model for the evaluation of the long first wave of the COVID-19 pandemic in Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuanji Tang ◽  
Tamires D. A. Serdan ◽  
Amanda L. Alecrim ◽  
Diego R. Souza ◽  
Bruno R. M. Nacano ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Growth Rate ◽  
Good Accuracy ◽  
Simple Mathematical Model ◽  
Epidemic Curve ◽  
Local Characteristics ◽  
Stable Period ◽  
Long Duration ◽  
Short Period ◽  
The Impact

AbstractWe propose herein a mathematical model to predict the COVID-19 evolution and evaluate the impact of governmental decisions on this evolution, attempting to explain the long duration of the pandemic in the 26 Brazilian states and their capitals well as in the Federative Unit. The prediction was performed based on the growth rate of new cases in a stable period, and the graphics plotted with the significant governmental decisions to evaluate the impact on the epidemic curve in each Brazilian state and city. Analysis of the predicted new cases was correlated with the total number of hospitalizations and deaths related to COVID-19. Because Brazil is a vast country, with high heterogeneity and complexity of the regional/local characteristics and governmental authorities among Brazilian states and cities, we individually predicted the epidemic curve based on a specific stable period with reduced or minimal interference on the growth rate of new cases. We found good accuracy, mainly in a short period (weeks). The most critical governmental decisions had a significant temporal impact on pandemic curve growth. A good relationship was found between the predicted number of new cases and the total number of inpatients and deaths related to COVID-19. In summary, we demonstrated that interventional and preventive measures directly and significantly impact the COVID-19 pandemic using a simple mathematical model. This model can easily be applied, helping, and directing health and governmental authorities to make further decisions to combat the pandemic.

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