Sharif Digital Repository

For the past few years, increasing the airspace capacity has been one of the most detrimental issues facing air traffic management. Statistically speaking, the demand for aerial transportation has been continuously growing hitting an %8.1 growth in 2017. This growth rate in conjunction with the performance and safety considerations for the ATC systems, clearly indicate the need for a practical and safe solution to the airspace capacity problem. Dynamic Airspace Configuration (DAC), is one of the proposed methods addressing this problem by changing the airspace configuration over time.In this research, we have introduced an intelligent method for airspace configuration given the forecast of... 

Cardiovascular diseases are the leading cause of death globally so early diagnosis of them is important. Many researchers focused on this field. First signs of cardiac diseases appear in the electrocardiogram signal. This signal represents the electrical activity of the heart so it’s primarily used for the detection and classification of cardiac arrhythmias. Permanent monitoring of this signal is not possible for specialists so we should do this by means of Artificial Intelligence. In this thesis, we use recurrent neural networks to classify electrocardiogram’s arrhythmias. This deep learning method, use two sources of data to learn from. The first part of data is global for everyone and the... 

The case of rapid small satellite aerial launch by mother airplane has various applications; such as space experiment, weather monitoring, and getting information from the earth monitoring during natural disasters. In this method, the satellite and the launch vehicle will be carried up by mother airplane to the definite height; then, the launch vehicle will be released and flied - to the insert of satellite into the desired orbit. Aerial launch system success depends on a set of complex elements and their interactions. In the present study, first of all, the element interactions will be investigated by system engineering approach based on operational scenarios; then, a new approach for... 

This study explores the trajectory optimization of two aircrafts’ formation flight seeking minimization of fuel consumption and flight duration while considering activation of the Traffic Collision Avoidance System (TCAS) during the flights. In order to model the effects of this system, a set of codes has been developed in the Matlab software environment, which utilizes an estimation model of induced drag for each aircraft by their relative positions. Also, position rotation is allowed, and the number and location of rotations are controllable by the user. The TCAS determines the allowable distances between aircrafts during flights based on relative velocities and relative heading angles.... 

Today global network of transportation is mainstream for economic growth and business development, growth in population made a need in optimization of using routes in global air transportation network, research shows cooperating with Airline Alliances is beneficial and gives much more freedom to their members in schedule planning and pricing as well as common interest in market share in international market. Joining an alliance affects decision making process of airline (e.g. fleet design, scheduling, route planning and crew assignment) in competitive market. Difficulty and complexity of evaluation in cooperative decision making that needs research to develop a model to evaluate decision... 

The objective of this research is to develop a mathematical model for analysis and design of airport cities. In this model, the interactions among the elements of an airport city -regarded as a complex system- will be analyzed, and the impact of the stakeholders’ requirements on the functional and physical architecture of the airport city will be investigated. So as the first step, the stakeholders of the system and their requirements are identified and classified. Second, the concept of operation of the airport city is investigated, and then the architecture of the system is modeled as a queuing network. So that each element of the airport city is regarded as a service center, including the... 

The main goal of this research is to reduce aircraft design cycle period, by reducing the necessary number of design cycle iterations. The Design cycle period is one of the main characteristics of the design process and design cycle iterations play a major role in the design cycle period. To achieve the above mentioned goal, we present a mathematical model of iterations for the aircraft design process. This model describes the design coupled tasks as a discrete-linear time invariant dynamic system. This model also helps identify tasks which are the most important for generating iterations. This new method basically helps break information cycles that create iterations among important tasks.... 

Considering the annual growth in the air traffic, new challenges arise; one of which is the appropriate level of automation that needs to be brought into the picture. This research focuses on the characteristics of a high level automation device, such as level 6 and upper, which could be used onboard a transport for traffic conflict prevention. The main objective behind such a device is to help ground controllers in crowded airspaces. In this work, we discuss the abilities of a new algorithm to resolve a general conflict in the absence of ground based ATC centers. The proposed algorithm considers the Earth rotation as well as general wind patterns. Mathematically, it is based on real-time... 

This work describes a methodology to enhance aircraft performance via proper mass distribution management. The methodology aims to limit aircraft configuration in early stages of the design process to its desired performance. Mass Distribution Management (MDM), that is used in this work, is a new mathematical model which predicts the so-called aircraft Handling Qualities (HQ) via proper positioning of aircraft mass. This work shows how proper changes in B-747-100 fuel tanks arrangement can enhance its flight quality up to level one during its entire cruise flight without use of any stability augmentation systems. In general this work introduce a methodology to examine different fuel tanks... 

Airline scheduling is a dynamic process in nature such that it changes not only during one year period but also in smaller intervals due to the economic, political, religious, and social factors. Basically, airlines schedule planners through using mathematical models decide which flights are to be served in what periods of time and at what costs. This has to be done considering a set of constraints of different nature, from airspace and airport congestion up to climatic conditions or even crews working conditions. Such a complex problem requires different methods for an efficient solution. In this study by using network optimization method and applying different operational constraints on... 

In this work, we investigate how the so called “Game Theory” could be applied to study the effectiveness of the defensive layers of a high-value target. A High-value target is usually protected by different defensive layers; the characteristics of which very well depends on the attacker capabilities. Here, we show “Game Theory” can effectively provide new alternatives to increase the chance of survival for the “High Value” target by increasing the risks for the attacker. In this work, we assume any attack is not executed in one stage and defensive layers could be designed to increase the duration of the game. We also assume the game ends as soon as there are no more weapons d to protect the... 

Towards basic-applied Research in the System Sciences fields, this Research has been to try to understand the behavior patterns and Functional Architecture of parasitic organisms and Use these in Social-Economic Systems. In this research four scenarios for parasite behavior were found and based on one of them, the recent "Financial Crisis in Greece" has been evaluated. The results show that the developed model, can be effective in similar conditions.
 

In order to manage a complex system, one way is to divide it into smaller parts. That’s the reason airspace in each country should be divided into sectors. Currently, these sectors have fixed areas and each is controlled by a number of air traffic controllers. However, the traffic crossing these sectors is considerably dynamic, which means the traffic density and its distribution varies seasonally, weakly and even through the 24 hours of a day. Moreover, weather conditions and security and military issues make constraints to some of these sectors. This sometimes results in some high traffic sectors while some others have very low traffic density which causes two main problems. One is that,... 

This work, with the help of FUZZY DEMATEL and FUZZY TOPSIS methods investigates the behavior of a general transportation system. In fact, we have been able to develop a cause and effect model to describe why in an unsustainable system any increase in the so called “human value” would not help increase the overall system’s sustainability. Moreover, we have been able to analyze the new role of the key stakeholders as “insurance companies”. in fact, such companies receives a guaranteed flow of money without providing any extra services in the current unstable situation which help widen the gap and increase the rate of instabilities. Further investigations might be necessary to examine the role... 

Supply chains are socio-technical engineering systems which now days perform in more uncertain operational environment than before. These systems have been vulnerable because of increasing the number of natural disasters, competitiveness and changing the demand. So these systems in order to be survived in such high uncertain environment need to enhance some capabilities in their structure. In this research by considering an assumed auto supply chain, we try to develop an approach to cover uncertainties in operational environment of this system. At the next step, we use design structure matrix modeling to model the interactions between system elements before and after scenario occurring.... 

In the class of unmanned air vehicles (UAV), there is a class entitled as Quad-rotor that engineers pay much attention due to specific features to them. Main applications of this class are because of vertical take-off and landing capability and high controllability. This class has high controllability in environments with high barriers because of the inherent imbalance. All of the Quad-rotors have already studied, had a fixed structure. So the designer's main focus was on improving the guidance and control systems and almost all forms of linear and nonlinear control methods and fuzzy, adaptive and robust control have been investigated. In this study variable structure is examined instead... 

Functional Requirements (FR) are traditionally known to be "input" as far as an engineering process is concerned. However, for a Systems Engineer (SE), this is not the case. A well-known task of a SE is, in fact, to develop FRs from what is considered as the customer needs. The traditional approach to develop suitable FRs involves an algorithmic procedure; which mostly relies on the skills, knowledge, attitude, and experiences of the SE or experts members of design team. It is therefore an ad-hoc method which results in quite a few numbers of trial-errors and its effectiveness only reveals itself as time goes on. The current work aims to address such a shortcoming in Systems Engineering... 

This work presents a novel approach to redefine a safe aircraft based on systems engineering fundamentals. Its aim is to prescribe a “Safe-Functional-Aircraft” instead of currently used procedures that is based on “Physically-defined-Safe-Aircraft”. The current work is much more consistent with increasing number of flights. It basically suggest that any aircraft that can complete its mission should not declare emergencies due to any physical malfunction. With proper simulations, have investigated the feasibility of replacing a “physically safe” aircraft with an “operationally/functionally safe” one. The process makes use of well-known documents such as FTA and FMEA ; which are produced... 

This work describes a new approach to the so called “Engineering Requirements Process” based on abilities to develop a meaningful task. We first describe how a meaningful is created from scratch and then we explain how requirements could be added to a level where the predefined task is no-longer doable. The process is then applied to design of an aircraft wing to show how requirements could be avoided during a design process. The method is expected to be applicable to all aircraft sub-systems and parts. The process is particularly useful where all design requirements are not available at once, rather they increase as time goes on and new stakeholders become apparent. In this work, we have... 

The purpose of this thesis is to present a novel approach in Terrain Following/Terrain Avoidance (TF/TA) flight using Fuzzy Logic. The fuzzy logic can decide where and how the aircraft needs to change its altitude and/or heading angle. The method due to its fast decision making algorithms would be useful for on-line operation. It could also help design trajectories in an off-line manner. To achieve the above goal, the method effectively incorporates the dynamics of the aircraft and could handle tough terrains in terms of shape and peculiarities. The mathematical method basically, uses a special relationship among existing slope and slope derivative of the terrain together with aircraft...