Quadrotors have high energy consumption due to their inherent structure, hence minimization of their energy consumption play a crucial role in terms of enhancing their operational range and flight time. In this paper, optimal control based on a minimum-energy trajectory planning algorithm of a quadrotor has introduced between two certain points to maximize operation time. To do this, first, dynamic equations of quadrotor and Brushless motor are derived. Energy consumption of quadrotor is introduced as a cost function and the minimum energy path is determined using optimal control theory. To satisfy constraints, all of them are combined with a Hamiltonian equation using Lagrange multiplier. Finally, simulation results are compared with results of conventional trapezoidal velocity profile which shows energy saving up to 4% compared with conventional trapezoidal velocity profile. Also, results reveal that the influence of operation time is far more than path length on energy consumption. In order to verify the validity of the simulation results, they are compared with the results of an experimental model which is consisting Brushless motor, sensor and, control board. As well as using simulation results in different situations, a mathematical equation was extracted among path length, operation time and energy consumption which can be useful to estimate the maximum flight range or operation time considering the amount of energy of the battery.

The insect flight mill is a device that used for studying insect flight. With this tool, the main parameters of flight such as distance, speed and duration can be calculated and analyzed. In addition to the aerospace field, which focuses on improving and optimizing existing flying devices and can be inspiring for the construction of micro air vehicle (MAV), it is also used in agriculture to combat pets and increase the quantity and quality of agriculture products. This article discusses the design and construction of a sample insect flight mill device that provides researchers with valuable and extensive information on insect flight performance while being simple. After a brief explanation of the various exiting methods in insect flight research and the introduction of insect tethered flight device, the governing equations of the device are presented. Then, the construction method and testing procedure are described, followed by an analysis and comparison of the obtained data with similar and upgraded devices. Finally, the advantages and disadvantages of the device are discussed.

The radio communication of air traffic controllers with pilot airplanes is critical to their guidance and control during flight times due to the high risk of air operations. If a disruption occurs in this connection and it is possible to exclude the possibility of directing the flight from the controller, there will be a probable occurrence of any adverse event, and consequently the lives of several hundred people will be at serious risk. Therefore, this paper intends to investigate the need for proper and secure communication between air traffic controllers and pilots to prevent adverse events and reduce the proportion of air accidents. The research population is the documents and experts related to the subject. Using a questionnaire and interview with experts, an applied research was conducted using a descriptive method and a qualitative approach with field and library methods and the results were analyzed by mixed method. Finally, it became clear that the air traffic controllers and airline companies should equip all the aircraft and ground control stations with data transmission systems equipped with automatic encoder systems with electronic warfare capabilities in the context of the ground-based and air-based communication network, and of course, in the future space-base, and should act in such a way as to exchange reliable information so that radio communications can be sustained and quick.

Depending on the purpose, different species of broadleaf and coniferous trees are used in the urban green space, which has diverse and complex characteristics. In this study, to obtain accurate information about trees and to cover the weaknesses of two technologies, TLS and TOF, their combination was used. For this purpose, 20 trees were selected from broadleaf (Fraxinus Ornus L. & Ulmus umbraculifera) and coniferous (Cupressus sempervirens L. & Cupressus arizonica Greene) species in the green space of Khajeh Nasir Toosi University and their point clouds were produced using TLS and TOF. After processing point clouds, the parameters of breast diameter, basal area, and crown area were measured. The RMSE of measuring the diameter at the breast of broadleaf and coniferous trees using TOF technology was 0.33 and 0.38 cm and TLS technology was 0.59 and 0.62 cm respectively. The diameter measurement error of the broadleaf is less than the coniferous due to the thinner bark. The basal area measured using TOF technology is more accurate than TLS; On the other hand, TLS technology has a precise and unique function in measuring the crown area. The basal area and crown area of broadleaf trees showed more errors than coniferous trees due to the asymmetric and irregular shape of the stem and crown. According to the obtained results and the examination of the strengths and weaknesses of these technologies, the combination of these two leads to more accurate and comprehensive results. Therefore, it is recommended to use the integration of these technologies in detailed scientific studies that are the basis of executive works.

The lack of efficient inventory tools is an old and well-known problem related to in situ forest measurements. Time of flight technology (TOF), using photogrammetric techniques and the ability to detect depth, allows the creation of 3D point clouds and the measurement of various objects, including tree stems. Therefore, this paper presents the accuracy of diameter measurement with TOF technology compared to calipers for six tree species: (Fagus orientalis Lipsky), (Quercus castanaefulia C.A.M. subsp), (Acer velutinum Boiss), (Carpinus betulus L.), (Alnus subcordata C.A.M.), (Parrotia persica C.A.Mey.), differing in stem shape and bark (20 of each species) were studied in the Darabkola Research Forest. Then, the diameters at a height of 1 and 1.30 metres of the tree trunks were measured with a vernier calliper and a point cloud was created using a Phab 2 Pro smartphone. The target diameters were measured using the CloudCompare software. The results showed that there was not much difference between the field recordings and the TOF measurement. However, Acer velutinum, Fagus orientalis and Quercus castanaefulia had fewer measurement errors than Parrotia persica, Alnus glutinosa and Carpinus betulus. Overall, the diameter RMSE at a height of 1 m and 1.30 m was 1.01 cm and 0.87 cm, respectively. According to the Bias index, the values measured with the TOF technology were higher than those measured with the caliper for most species were. Due to the results obtained and the many possibilities of TOF technology, such as the possibility to measure the diameter at different heights, the creation of RGB-3D, the high scanning speed and accuracy, low complexity, the brightness and the lower cost than other technologies, three-dimensional surveying is a good option for forest inventory verification.

Airlines are faced with some of the biggest and hardest scheduling problems known. For example, one major US carrier periodically schedules about 2700 flights per day to over 130 cities, using more than 400 aircrafts of 14 different kinds. Flight scheduling is one of the major problems for any airline company. This problem has been investigated as an optimization problem for many years. Usually, the flight scheduling problem is divided to a number of sub-problems, and fleet assignment is one of them. In this problem, given a flight time table and aircraft specifications, the type of aircraft is determined for each flight or the fleet assignment problem is the problem of assigning the right aircraft type to the rights in the timetable, while minimizing costs and satisfying various constraints. A lot of money can be saved if the right aircraft types are used. For example, in 1994, Delta Air Lines estimated that the use of a newly developed fleet assignment system would yield savings of up to $300 million over the following three years. The trade off between different aircraft types is that with a larger aircraft, more passengers can be serviced, and thus more income is generated. On the other hand, a larger aircraft consumes more fuel and is generally more expensive to operate. The fleet assignment problem (FAP) in air transportation consists of assigning fleet types to flights of a given flying schedule while respecting feasibility constraints and maximizing expected profit. Expected operational costs can be quite accurately expressed as a linear function of the FAP decision variables. The same cannot be said of expected revenues. Future revenues depend mainly on future travel demand. A particular fleet assignment (FA) then affects revenues through capacity limitations. Hence, when one expresses the expected profit as a linear function of the FAP decision variables, it is implicit that it is based on demand forecasts and that this linear function is only an approximation, a tool whose efficiency is to be judged on the profitability of the FAs found by the FAP solver. Because of this tight economic link, the fleet assignment problem is often connected to a revenue management system, which gives information about that is the best aircraft type for an individual flight, from a purely economic point of view, considering the booking situation and other things. But if the best aircraft type for each individual flight is already known, then what is the problem, you might ask. Just assign the best type to each flight, and the problem is solved. But this is obviously a typical example of a way in which one problem in a sequential solution procedure can ruin the possibilities for the following problems. It could for example mean that an aircraft would have to make a large amount of flights without passengers, so called deadheads, to operate its flights, because they are scattered geographically. This is likely not a very good solution. In recent studies, the fleet assignment problem has been modeled as a multi-commodity network flow problem with integer and real variables, and solved by conventional methods. In this research, we modify one of the existing models for domestic airline company and use Genetic Algorithm (GA), Simulated Annealing (SA) and Ant Colony Optimization (ACO) to solve it. These algorithms were implemented for the fleet assignment problem and used to solve a sample problem. Comparison of results of solving the sample problem by algorithms and GAMS software indicates that, GA, SA and ACO have good capability for solving the fleet assignment problem.

In this paper، a new guidance law for yaw channel of homing interceptors is designed. Because of using the sliding mode theory، the nonlinear equations of motion are used and the target acceleration is considered as an uncertainty. Therefore، the precise measuring or estimating of target acceleration is not required and only the upper bound of target maneuvers is used. A sliding surface is defined using the angle rate of the interceptor target line of sight. For producing a smooth control signal and removing the chattering of the guidance commands، the discontinuous term of guidance law has been approximated with a continuous function. Adjusting the parameter of sliding term leads to decreasing the missile control effort، the time of flight and velocity loses. Simulation results in the presence of a real control system dynamics of a homing interceptor show the effectiveness and robustness of the designed guidance law against maneuvering target in comparison with the proportional navigation algorithm.

Despite the traffic increases at the World airports, little works have been done to improve vehicles and airplanes services, increase efficiency and decrease service automobile voluminous of large number. With GIS abilities, airport managers would like using its potential for development and management of airports. So new issue in GIS is formed with AGIS title to study GIS applications in airport as wide and corporation all world airports and GIS specialists.This paper presents an application of GIS analyses in airport field. The main innovation of this research is offline spatiotemporal data analysis and introducing an efficient algorithm for service automobiles allocation optimization with reduction in departure time deferment constraint. Allocation has been done by considering the aircraft push and tow required time and its distance to a service car. In this proposed solution servicing operation optimizes with considering two situations: one that service car returns to its Equipment Parking Area or EPA when delivering service and in another situation service car parks in Equipment Staging Area or ESA. Numerical results of using proposed method in Mehrabad international airport indicate in both situations, departure delay is lesser than usual method. Outcomes of minimizing service cars are: traffic reduction, increase management efficiency, decrease hazards due to large number of service cars and increase safety in airport field.