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Reliability of high precision linear motion system is one of the main concerns in industrial and military systems. The performance and repeatability of these systems are influenced by their respective linear drives and load bearings. A fault in these members severely affects the safe working of overall system. This paper gives a reliable intelligent approach to detect and classify faults for linear motion systems based on deep learning methods. Accuracy in faults identification is highly dependent on improved features extraction. For this purpose, a novel Residual Twin CNN (ResT-CNN) is proposed that uses combination of 1-D and 2-D CNN in parallel learning which improves features extraction performance; followed by knowledge base-Remnant-PCA (Kb-Rem-PCA) architecture in combination with multi-class support vector machine (Mc-SVM). This novel hybrid combination proved very effective in accurate faults identification. The performance of proposed methodology was also validated by IMS-UC (Intelligent Maintenance Systems – University of Cincinnati) public bearing dataset. The results confirm the effectiveness of proposed scheme in comparison to existing state of the art techniques.

A comprehensive design cycle of a nose landing gear strut having an oleo-pneumatic shock absorber for a lightweight aircraft is proposed. Design and analysis of a retractable nose landing gear according to Airworthiness Standards FAA FAR Part 23 have been carried out. This research is focused on mathematical modeling of an oleo-pneumatic strut with an analytical solution of design variables at static and dynamic loading conditions. The variation of spring and damping characteristics of an oleo-pneumatic shock absorber with the stroke length is also presented. Feasibility of equivalent mechanical spring and damper along with comparison of pneumatic as air spring and oleo as hydraulic damper is studied. Numerical integration technique was used to solve the dynamic model of an oleo-pneumatic strut with forcing function of an impact force during touch down scenario. Energy conservation principle was used to determine height required for drop tests. Parametric study of anteversion angle within the constraints of ground clearance and volume in the fuselage determined an optimized angle of nose landing gear strut. Based on the maximum pressure and impact force encountered during landing, the hydraulic cylinder and piston design was finalized. In order to validate the proposed design cycle for preliminary phase, a structural integrity of cylinder and piston assembly was carried out using finite element analysis. Deformation, maximum stresses and factor of safety validated the proposed design cycle of a nose landing gear strut specific to a general aviation aircraft having all up mass of 1600 Kg.

Micro aerial vehicles using flapping wings are under investigation, as an alternative to fixed-wing and rotary-wing micro aerial vehicles. Such flapping-wing vehicles promise key potential advantages of high thrust, agility, and maneuverability, and have a wide range of applications. These applications include both military and commercial domains such as communication relay, search and rescue, visual reconnaissance, and field search. With the advancement in the computational sciences, developments in flapping-wing micro aerial vehicles have progressed exponentially. Such developments require a careful aerodynamic and aeroelastic design of the flapping wing. Therefore, aerodynamic tools are required to study such designs and configurations. In this paper, the role of several parameters is investigated, including the types of flapping wings, the effect of the kinematics and wing geometry (shape, configuration, and structural flexibility) on performance variables such as lift, drag, thrust, and efficiency in various modes of flight. Kinematic variables have a significant effect on the performance of the flapping wing. For instance, a high flap amplitude and pitch rotation, which supports the generation of the strong leading-edge vortex, generates higher thrust. Likewise, wing shape, configuration, and structural flexibility are shown to have a large impact on the performance of the flapping wing. The wing with optimum flexibility maximizes thrust where highly flexible wings lead to performance degradation due to change in the effective angle of attack. This study shows that the development of the flexible flapping wing with performance capabilities similar to those of natural fliers has not yet been achieved. Finally, opportunities for additional research in this field are recommended.

Main landing gears are a critical structural part of an aircraft that support all up weight in static conditions and absorb kinetic energy in a form of impact loads during touchdown. High strength and low weight are critical design considerations for any landing gear strut. During this research, carbon reinforced composite strut was optimally designed such that it undertakes static loads and impact loads of a UAV having GTOW of 1600 kg. CAD models of the designs were developed in CATIA V5R20® and the analysis was carried out in ANSYS Workbench®. Rectangular, circular and elliptical cross-sectional shapes were modeled in ANSYS ACP® with different ply orientation sequences and varying weight distributions from central axis. Least total deformation along with least equivalent stress and aerodynamic drag was considered for the selection of landing gear strut configurational shape. Further design changes in the selected CAD model were incorporated keeping in view the safety factor of the struts. We concluded that 60 preimpregnated carbon reinforced fiber with thermoset polymer matrix having 0.27 mm of thickness for each ply at specified concentration and orientation gave the best results. The orientation of plies was found to be 60 %/ 0°, 30 %/ 45° and 10%/ 90°. Maximum deformation for the final model was 42.154 mm at the joints where the axle was connected with the strut whereas the maximum stress was 712.92 MPa at the joints representing the connection of the landing gears with the fuselage. Drag force for each cross-sectional shape was computed at the takeoff speed of 30 m/s. Drag force for the rectangular cross section was 50.23 N whereas for the circular and elliptical cross section was observed to be 36.837 N and 16.744 N respectively. Hence research concluded that elliptical cross-sectional shape presented least stress distribution and deformation values.

Precise and reliable segmentation of vertebral column is crucial for accurate computer aided diagnostic system (CADx). It assists the radiologists and doctors in identifying various pathologies in the vertebrae with better visualizations. Accurate segmentation of vertebral disks and bones from the medical images is a tough job and becomes more challenging when dealing with various deformities and pathologies. While remarkable success was achieved by deep convolutional neural networks (DCNNs) in medical image segmentation, it is still a difficult task for DCNNs to handle the medical image segmentation problems with various deformities and anatomical complexities. In this paper, we propose a novel and efficient framework to address the subject problem by integrating a parametric level set approach in deep convolutional neural networks. The proposed scheme utilizes the probability map of pre-trained deep network to initialize the level set and it refines the output iteratively under the action of various forces to fine-tune the training of deep network. Thus the learning of the network is improved and the network is able to accommodate high topological shape variations in the vertebrae. This proposed method was evaluated on two different datasets. The first one is 20 publically available 3D spine MRI dataset to perform disc segmentation and the second one is 173 computed tomography scans for thoracolumbar (thoracic and lumbar) vertebrae segmentation. The dice score was found to be 90.37 ± 0.9 percent for disks segmentation and 94.7 ± 1.1 with ASSD of 0.1 ± 0.04 mm for thoracolumbar vertebrae segmentation. The results reveal that our proposed method is robust over multiple segmentations and outperformed the recently published state of art methods.

A unique approach of analyzing jet exhaust nozzle integrated to aircraft and propulsion system is presented in this paper. Engine exhaust nozzle is usually omitted in Wind Tunnel Testing and numerical analysis of aircraft due to complexities involved in integration of nozzle and presence of high pressure / temperature inside exhaust nozzle. Also, the flow properties are non-uniform and highly turbulent in the vicinity of nozzle. Therefore, exhaust nozzle is usually analyzed in isolation and these results often lead to inaccuracies from actual scenario where nozzle is integrated with aircraft and its propulsion system. This research aims to integrate engine exhaust nozzle on a supersonic fighter aircraft and analyze its flow characteristics and variation in performance parameters due to its integration. Engine propulsion characteristics and parameters such as nozzle inlet temperature and total pressure have been analyzed through an in-house validated engine analytical model developed by some of the authors of this study. In the first part of paper, exhaust plume structure has been analyzed to study the flow behaviour (flow turbulence and flow distortion etc) at nozzle exit. Later, nozzle performance parameters such as Exit Velocity, Nozzle Pressure Ratio (NPR), Engine Pressure Ratio (EPR), and Engine Temperature Ratio (ETR) have been calculated when exhaust nozzle is integrated with the aircraft. Finally, the results are compared and validated with analytical calculations to compare the performance of nozzle when it is in isolation and when it is integrated on aircraft. It is observed that nozzle flow has no significant effect on aircraft major surfaces such as fuselage, wing upper and lower surfaces, and nose section. However, there is a prominent effect of exhaust nozzle flow on horizontal stabilizers, vertical tail and rear fuselage area of the aircraft. An average difference of 18% in NPR, 12% in EPR, and 9% in ETR is observed between integrated nozzle and isolated nozzle which further signifies the importance of integrating exhaust nozzle in aircraft analysis. This proposed methodology will allow more accurate analysis of the effects of exhaust nozzle on the overall performance of aircraft. The methodology can further be used for proposing design changes in existing nozzle configurations.

Multirotor unmanned aerial vehicles (UAVs) have gone from a single rotor to multiple rotors. Multirotor unmanned aerial vehicles (UAVs) are now used for surveillance and rescue operations. These are used for surveillance over disastrous areas and to perform necessary rescue action. The capacity of multirotor UAVs to carry heavy payload is less with small and limited propellers. Therefore, the number of propellers have been increased, and ultimately the size of multirotor UAV has also been increased. The rotor arrangement is fundamental in the thrust of multirotor UAVs. The opensource software has been developed to integrate with the flight controller hardware. The current focus of research is to reduce the size of multirotor UAVs and increase the payload capacity of multirotor UAVs. The thrust has been reduced in case of overlapping rotor configuration, such as in coaxial and half propeller overlap configuration. These configurations are adopted to reduce the size of multirotor UAV. In this study, different multirotor UAV configurations have been studied for selection of best configuration for small but heavy-lift multirotor. The overlapping configurations have been found to increase the payload and reduce the size of the multirotor. The thrust has been increased to about 90% in the case of some propeller overlap configuration with a rotor plane angle. For coaxial configuration, the rotor thrust was about 76% of the thrust of the independent rotor. The thrust generated by the flat configuration is more than the coaxial and less propeller overlap configuration. The flight controllers are responsible for the stability and control of UAVs. Many flight controllers are working on the latest technology and can be programmed for various features. The flight controllers also contribute to increasing stability. Mostly open-source software is available to integrate with the flight controller hardware. The ARM-based flight controllers like Pixhawk flight controllers are the best to control the multirotor. These flight controllers can be programmed quickly and can be installed on the multirotor.

Pakistan has been frequently hit by natural disasters in the recent past, and the frequency of such disasters is on a rise. National agencies work hard to cope up with the situations to save precious human lives; however, there is still a dire need to develop capable and potent platforms which can fly remotely over difficult terrains and can provide comprehensive picture of the affected areas. For this purpose, in this research, a long range video telemetry system has been developed for use on an aerial platform, an RC helicopter, to make it fly worthy beyond visual range through video signal and other flight sensors data. The proposed vision system consists of a camera, GPS, altimeter, stabilization sensor, air speed sensor, G-sensor and temperature sensors. In order to save the payload capacity of our helicopter, a box has been designed and manufactured from glass reinforced plasticto make it lighter. This box contains separate compartments for the transmitter and other flight data sensors. The video signal is obtained from on-board camera, and other data is overlaid on this video stream and is then transmitted at 2.4 GHz frequency from a long distance. After receiving and amplifying the video signal, the telemetry data is extracted and used as a real time visual feedback to control and maneuver the RC helicopter through communication system when it goes beyond the visual site. The developed vision system is successfully tested from 48 km line-of-sight distance. It is a low cost, small size, light weight and power efficient vision system that can be installed on any ready-to-fly RC helicopter with as low pay load capacity as 2.0 kg.

Owing to non-availability of adequate data for situational analysis and requisite rapid surveillance equipment, initial response for relief efforts remains delayed during national calamities in Pakistan. As every second counts in humanitarian logistics, many precious lives are lost until initiation of relief and rescue operations. It necessitates development of a potent system able to spearhead relief and rescue operations by providing realtime situational analysis right at the onset. The research objective is to develop a disaster relief aerial platform indigenously, capable of providing quick and cost effective solution for initial disaster survey and relief efforts. Firstly, Rotary Unmanned Aerial Vehicle was scrutinized as basic platform, which was assembled after classification of each component. To achieve enhanced range operations, Flight Control Communication System with enhanced range and customized Beyond Visual Line Of Sight Telemetry system were integrated on the RUAV. Evaluations to verify the intended results and reliability of the developed system conceded a number of ground tests alongwith successful flight tests. The developed RUAV with integrated Enhanced Range Flight Control System and BVLOS Telemetry System is a novel platform able to provide feedback for situational analysis as well as for relief efforts during calamities.

Landing gear system of an aircraft enables it to take off and land with safety and comfort. Because of the horizontal and vertical velocity of aircraft, upon landing, the complete aircraft undergoes different forcing functions in the form of the impact force that is absorbed by landing gears, shock absorbers, and actuators. In this research, a selection methodology has been proposed for an electrical actuator to be installed in the retraction mechanism of nose landing gear of an aircraft having 1600 kg gross takeoff weight. Nose landing gear and its associated components, like strut and shock absorbers, were modeled in CAD software. Analytical expressions were then developed in order to calculate the actuator stroke, translational velocity, force, and power for complete cycle of retraction, and some were subsequently compared with the computational results that were obtained using MSC ADAMS&reg, Air in the oleo-pneumatic shock absorber of nose landing gear was modeled as a nonlinear spring with equivalent spring constant, whereas hydraulic oil was modeled as a nonlinear damper with equivalent damping constant. The nose landing gear system was modeled as a mass-spring-damper system for which a solution for sinusoidal forcing functions is proposed. Finally, an electrical actuator has been selected, which can retract and extend nose landing gear, meeting all of the constraints of aircraft, like fuselage space, aircraft ground clearance, locking loads, power consumption, retraction and extension time, and dynamic response of aircraft. It was found that the selection of an electrical actuator is based upon the quantification of forces transmitted to electrical actuator during one point load at gross takeoff weight. The ability of retraction and extension time, as dictated by Federal Aviation Regulation, has also been given due consideration in the proposed methodology as significant criteria. The proposed system is now in the process of ground testing, followed by flight testing in the near future.

Aerodynamics plays a very important role in all the sports in which a sports ball is thrown, kicked or struck. In all these sports the intent is to either throw the ball as far as possible, or to get an unpredictable swing of the ball to deceive the opponent. Soccer is one of the most played and watched sports today and the only equipment it uses is a soccer ball. Owing to increasing importance and popularity of soccer, a lot of research has been done recently for better understanding of aerodynamic parameters and flight path of soccer ball. Knowledge of effects of aerodynamics on soccer ball can be very significant for players who can incorporate that knowledge in their playing tactics. Similar research can also play a significant role for the ball manufacturers to design and manufacture soccer balls that can favor the aerodynamics of the ball in order to make the sport more exciting to play and watch. Small variations in the design of ball like panel size and method of attachment of panels can change the aerodynamic properties of the soccer ball. Velocity, spin and surface are major contributors towards variation in flight path and aerodynamic parameters of the soccer ball. In this work 3D Computer Aided Design models have been developed and their aerodynamic parameters have been calculated through Computational Fluid Dynamics. Effects of surface geometry have been analyzed numerically for smooth sphere and a soccer ball. Validation of results have been done for comparison of results obtained through commercially available solver and wind tunnel tests ofvarious authors. The difference in results obtained through numerical and experimental means have been analyzed and discussed. These results have also been compared with results obtained by various researchers using different numerical and experimental techniques. Recommendations have been made for all significant aerodynamic design considerations of a better soccer ball.

Flying birds, bats and insects have always inspired humans to venture into developing bio-inspired flying machines. Such vehicles imitate flapping wing concept are also known as Ornithopters. Efforts to build such vehicles date back to 9th-century work by famous Arab scientist Abbas-Ibn-Firnas. Despite many efforts, design and development of such vehicle remained a challenge. The major limitation in this regard is the limited knowledge of related aerodynamic concepts like, Low-Reynolds number phenomenon, vortex induced lift, non-linear fluid structure interaction, high flapping frequency, low weight, complex mechanics, stabilization and controls algorithms. This review paper is aimed to provide an insight into recent developments in understanding the complex dynamics of flapping wing vehicles. Notable experimental works and numerical investigations have been discussed in details; special emphasis has been laid on computational techniques for analysing complex dynamics and design of flapping wing vehicles. Moreover, the modern trends in design, power requirement, motion control and mathematical modelling are also explored.

Linear electro-mechanical actuators are commonly found in a variety of critical dynamic systems including hazardous robotic applications and various aerospace applications, and are specifically designed on the basis of required operating functional parameters. The performance of electro-mechanical actuators significantly affects the performance of overall system. This paper works to improve the reliability of linear electro-mechanical actuators through analytical redundancy for critical applications. A fault diagnostic algorithm is designed based on dynamic mathematical model and a remnant filter is implemented to detect actuator faults. The remnant filter generates residual signal proportional to the induced fault. Fault detection thresholds are set and decision logic is established to compare residual signal with the lower and upper threshold constants. This designed diagnostic filter is tested experimentally on a fault diagnostic testing setup and results of designed model have been validated.

This work presents an eigenvalue-based flutter analysis of a light UAV wing, including identification of stability characteristics and evaluation of critical flutter speeds through a Two Degrees of Freedom (2-DOF) Reduced Order Model (ROM), followed by its numerical validation and a parametric study analyzing the effects of thickness of structural members of the wing on its flutter speed. 2-DOF bending and torsional flutter equations are derived herein using Lagrange's equations, which are transformed into an eigenvalue problem for identification of stability characteristics at specified flight conditions. Extension of this eigenvalue framework is used for evaluation of critical flutter speeds for a range of altitudes. A two-fold numerical validation has been carried out with Nx NASTRAN using k- and pk methods, and a reasonably close agreement amongst the results is observed. The work concludes with a parametric study, which presents the effect of thickness of structural members on the flutter speed.

Linear servo electro-mechanical actuators are very commonly found in a variety of critical dynamic systems including various aerospace applications and hazardous robotic applications. These actuators are specifically designed on the basis of required operating functional parameters. The performance of servo electromechanical actuators significantly affects the performance of overall dynamic system. This paper works to improve the reliability of linear servo electromechanical actuators through analytical redundancy for critical applications. A fault diagnostic algorithm is designed based on dynamic mathematical model and a remnant filter is implemented to detect signal errors. The remnant filter generates residual signal proportional to the error induced. Fault detection thresholds are set and decision logic is established to compare residual signal with the lower and upper pre-defined threshold constants. This designed diagnostic filter is tested experimentally on a fault diagnostic testing setup and results of designed model have been validated.

In this work, trajectory optimisation has been performed for a wing-body rocket assisted vehicle to compute the bestset of performance parameters including burn-out angle, angle-of-attack, bank-angle and throttle command that would result in optimal down-range and cross-range performance of the re-entry vehicle. An hp-adaptive Pseudospectral method has been used for the optimisation by combining the launch and rocket rocket-assisted re-entry stages. The purpose of the research is to compute optimal burn-out condition, angle-of-attack, bank-angle and optimal thrust segments that would maximise the down-range and cross-range performance of the hypersonic boost glide vehicle, under constrained heat rate environments. The variation of down-range/cross-range performance of rocket rocket-assisted hypersonic boost glide vehicle with bounds on diminishing heat rate has also been computed.

The use of Gurney flap for improving lift to drag ratio of airfoils has remained a success over the past years. Although its implementation on airfoil successfully enhances lift characteristics, however, it also creates additional drag by hindering the flow. Therefore, minimization of its drag penalty is an active area of research for enhancing its effectiveness. Techniques such as modifications in its shape, size and placement position has been incorporated in its design. These techniques lower the surplus drag of Gurney flap but it is not a significant decrease. Thus keeping the need of hour in view, this endeavor has been put in to minimize the drag penalty imposed on the installation of gurney flap. A shape modification has been analyzed and successfully proposed to maximize lift to drag ratio of the airfoil with gurney flap. The idea is to introduce the porosity in the gurney flap so as to minimize the stagnation pressure loss. The flow patterns and aerodynamic parameters have been evaluated and plotted using CFD techniques in ANSYS FLUENT software. The analysis has been done with various porosity levels on the flap height of 0.5, 1, 1.5, 2 and 3% of the chord. The results and the characteristics behavior have been compared and verified from with published results. From analysis it has been found that the most effective gurney flap configration is of height equal to 2-3% of the chord with 20% porosity. This analysis could be used as a guideline in development of better and effective design of Gurney Flap being used in aerospace industry.

The thrust of an aircraft or rocket engine is largely dependent upon the momentum imparted to the products of combustion by discharging them through an exhaust nozzle. The design of an exhaust nozzle has special importance in determining the thrust and performance of an aircraft / rocket. In recent years, the design of the exhaust nozzle has received considerable attention as it directly impacts the overall performance. The aim of this paper is to study the behavior of a velocity field at the exit cross section of an elliptical nozzle. In this regard, an algorithm has been developed using the governing equations to compute the velocity at the exit of an elliptic exhaust nozzle for various aspect ratios and widths. The algorithm also provides the maximum Mach number at the exit. Subsequently plotting of Mach number contours for a range of aspect ratios is carried out. Flow is assumed to be moving under the influence of a pressure gradient. The analysis of velocity profile at exit plane of an elliptical nozzle in subsonic, supersonic and hypersonic regime is carried out which provides an understanding of the behavior of flow with variation in aspect ratio or width of an elliptical exhaust nozzle. The velocity profile obtained from algorithm for different aspect ratio and width is then compared to find the optimal design. The criteria for the optimal design of an elliptical exhaust nozzle is delivering the maximum exhaust velocity and thus thrust which is of prime importance in the design of an aircraft exhaust nozzle. This exhaust velocity, leading to thrust, is dependent mainly on the configuration of the nozzle walls i.e. geometry of the exhaust nozzle. In future, experimental validation of these results is suggested using the wind tunnel and also through computational techniques. The same approach can be used to study exhaust nozzles of varying cross sections for example triangular, square, rectangular, circular etc. The study will help in the development of optimized aircraft exhaust nozzles for future advanced aircraft.

Solar pond is a stratified region capable of storing thermal energy obtained through solar radiations up to 95°C. This energy is extremely useful in various industrial applications ranging from electricity generation and desalination to refrigeration and hot water consumption. The ability of a pond to collect and store thermal energy in storage zone is dependent on effective stratification to suppress natural thermal convection. This stratified region is formed as a result of injection of a solution of varying salinity densities into a saline region. Once formed, maintenance of this stratified region is of utmost importance to trap maximum heat in the pond. This is carried out through injection of saline water through diffuser in specific regions to overcome the effects of dissociation. Diffuser design remained an area of utmost interest in the evolution of solar pond and detailed research has been carried out to overcome the effect of buoyancy in the stratified region and extend the range of plume emanated from the diffuser. Diffusers of varying designs and shapes including diffusers with round and rectangular outlets have been employed in solar ponds over the past few decades. Although researchers have concluded that semi-circular diffusers with rectangular slots are more efficient, yet limited research has been carried out to validate these results using Computational Fluid Dynamics. In research focus has been laid on diffuser designs and comparison of these designs followed by computational analysis of their effect on the emanating flow. Various CFD modeling approaches from the family of Reynolds-Averaged Navier Stokes (RANS) have been discussed in this research including the semi empirical k-E model based upon the dissipation rate and turbulent kinetic energy. Based upon these results optimum diffuser design for stratification in a salinity gradient solar pond has been established using CFD technique which has previously been studied on a limited scale. This has enabled in design of optimized gradient formation and maintenance mechanism.

Solar pond is a stratified region which stores solar energy in the form of thermal energy up to 95°C in its saline storage zone. This energy is used in various industrial applications ranging from electricity generation and desalination to refrigeration and hot water consumption. The ability of a pond to collect and store thermal energy in storage zone is dependent on effective stratification to suppress natural thermal convection. Diffusion and high temperature gradients result in encroachment of convective zones and development of additional internal convective zones. This results in degradation of stratification hence reducing the thermal efficiency of solar pond. In this scenario, maintenance of salinity gradient comes into play which involves monitoring of different parameters of the stratified region and injecting the fluid through diffusers controlled by feedback and control mechanism. Over the past few decades various methodologies have been developed for optimized maintenance of the stratified region. This research has thoroughly analyzed the gradient maintenance techniques, specifically focusing on injection mediums and their effects on the salinity gradient maintenance. The two configurations of injection medium i.e. injection of highly turbulent columnar jets into homogeneous convective zones and the injection of low exit Froude number fluid through a disk-shaped diffuser (most common) are elaborately analyzed and compared. Moreover, the effect of size & shape of the injector slots and followed by fluid velocity of injector on the flow pattern exiting the injection medium has been thoroughly analyzed. The analysis and comparison of different gradient maintenance and formation techniques show that flow discharge through a half disc shaped diffuser with rectangular slots at Froude No ranging from 12–18 is optimum for the stratified region. The analysis of an optimized injection mechanism has enabled formation and maintenance of a linearly distributed stratified region in the non-convective zone (NCZ) resulting in more heat collection in the lower convective zone (LCZ).

Cervical (neck) pain is becoming the leading issue worldwide. Accurate segmentation of cervical spine can assist radiologists and doctors in early and batter clinical diagnosis of cervical abnormalities. This paper addresses the challenging issue of cervical image segmentation. Various techniques have been proposed earlier, but still work is needed for accurate identification and segmentation of vertebral bodies. The technique required to segment out vertebra should be robust and invariant to variation in shape, noise, rotation, scale and occlusions. In this paper, we have presented a novel technique for cervical vertebrae segmentation, which is based on deep learning, i.e., U-Net. This technique would have an ability to capture information embedded in x-ray data images for segmentation purpose and have an ability to overcome noise and occlusions in batter and efficient way.

Over the past few years the popularity of unmanned aerial vehicles has kept growing at an unprecedented rate. These are being used for industrial as well as for military purposes. Most of the existing unmanned aerial vehicles are fixed wing and carry missiles and bombs hence they cannot be used for point defence. Hover capability is required for point defence which is an attribute of rotorcrafts. The rotorcraft with a gun mount with point defence capability is currently available which was developed by US Air Force. Pakistan has combat drones which are fixed wing so there is need of developing combat drones with rotorcrafts. The aim of this project is to develop an anti-terrorist unmanned aerial vehicle that can perform surveillance and reconnaissance with weapon launch system that will be installed on it to provide point defence. A brief history of usage of UAVs is discussed followed by different structural components that are used in assembly of UAV. The combat drone systems that are being used currently have been discussed along with some proposed modifications and improvements for better performance and increased efficiency.

Owing to the depletion of the fossil fuels and their ill-effects posed on the environment, the alternative renewable energy resources are receiving ever increasing focus of the modern world. Amid these resources, prospects of harvesting energy form the wind stand out because of its inexhaustible availability and cost-effectiveness. In spite of all the pros associated with the wind power, a con exists in the shape of low power density. Hence, to generate an amount of energy comparable with the other sources, numerous wind turbines are arrayed in a single wind farm. With this, arises the problem of wake interaction amongst the turbine arrays, owing to which, the downstream wind turbines exhibit a reduced output yield. This instigates a significant diminution in the efficiency of the succeeding wind turbines and, hence, their service life gets adversely affected as well. Much work has been inspired to attain a proper understanding of the wake interactions by developing wake interaction models. Notable amongst these models are the infinite wind farm boundary layer model, the Jensen model and its variant Jensen Park model, the Larsen model, FUGA and Ellipsys 3D model with RANS and LES variants. There exists enough data in the literature to prove that the Jensen’s wake model has long maintained its dominance over other models. This owes to its less computational cost yet with adequate accuracy in its predictions. In this work, an analysis of the velocity deficit aft of the wind turbine and its recovery along the downstream distance as calculated by the Jensen’s model has been compared with a case when a hybrid CFD-Jensen model technique is employed. As wind farm layout optimization is concerned with the optimal energy harvest through placement of maximum wind turbines within a limited area of the wind farm, the magnitude of output power losses along the downstream distance, becomes quite a significant concern. Hence, this analysis has been further extended to the estimation of output power losses as manifested by the succeeding wind turbines operating in the wakes, at different downstream distances. Furthermore, a comparative analysis of the angular spread of the wakes, as they travel downstream, is also presented. This study will be particularly useful for the cases when very little or no experimental data is available at hand, as it provides initial estimates for the wind farm layout optimization for optimal energy harvest.

For a fighter aircraft to operate effectively in severe weather conditions, an efficient and effective Environmental Control System (ECS) is one of the basic requirements. Accurate working of electronic equipment installed in cockpit and comfort of pilot require temperature, pressure and humidity levels inside the cockpit to be well within limits as defined in the Mil standard MIL-E-18927E(AS). In this paper, computational analysis of cockpit Environmental Control System (ECS) of a fighter aircraft for a designed (dry air) and an off designed condition (moist air) is presented. Certain flight conditions which are defined in the aircraft flight envelope are used to design an effective ECS of the understudy aircraft to ensure comfortable temperature environment for the pilot and electronic equipment. To validate ECS performance, analysis at the most severe environmental conditions (International Standard Atmosphere + 30°C while flying at 0.825 Mach Number at sea level) has been considered. Complete analysis of flow and temperature field inside the cockpit has been performed in FLUENT® for performance verification. In the first analysis, dry air properties have been used as per design. This is possible due to availability of water separator in the system design which removes most of the water vapors in the cold air coming from the cooling turbine before entering the cockpit. In addition, an analysis of ECS performance for an off design condition by assuming saturation/failure of water separator which results into provisioning of moist air in the cockpit has also been presented. ECS performance under both the conditions has been thoroughly evaluated with respect to MIL standard MIL-E-18927E(AS) and the results have been found satisfactory. It has been demonstrated that CFD techniques can be used to analyze the flow and temperature field inside the cockpit of an aircraft.

Atmospheric reentry vehicles have wing-body configuration with blunt leading edges on wings and slender fuselage. These vehicles pass through several phases of flight during ascent / descent and therefore their aerodynamic performance parameters vary from rarefied flow conditions to hypersonic continuum flow to subsonic speeds before final full stop. Measurement of temperatures on hot spots in hypersonic flow remained a challenge for a mankind. Re-entry vehicle covers wide range of Mach, angles of attack, angles of side slip and control surface deflections during its complete mission profile. Still today, scientists are facing challenges in recording real time precise data from hypersonic ground test facilities. These facilities although provide insight to flow physics, surface temperature and location of hot spots, yet they cannot match enthalpy, noise, Reynolds number, binary scaling simulation parameter, non-equilibrium chemistry contribution to friction and catalytic heating during hypersonic flight. Thermal protection system encompasses boundary layer physics, gas to surface interaction, high temperature materials and internal thermal management. TPS materials will be evolved only after true measurement of temperature and heat transfer rate. This research includes study of intrusive, semi-intrusive and non-intrusive temperature measuring technologies. It is concluded that E-type coaxial surface junction thermocouples are best suited for high enthalpy flows because they are robust and can survive challenging hyper velocity environment. Thin film gauges having better signal levels and less noise with more consistent response time but are useful for low enthalpy flows only.

In this paper, we present the procedure of estimating the aerodynamic coefficients for a commercial aviation aircraft from geometric parameters at low-cruise-flight conditions using US DATCOM (United States Data Compendium) and XFLR software. The purpose of this research was to compare the stability parameters from both pieces of software to determine the efficacy of software solution for a wide-body aircraft at the stated flight conditions. During the initial phase of this project, the geometric parameters were acquired from established literature. In the next phase, stability and control coefficients of the aircraft were estimated using both pieces of software in parallel. Results obtained from both pieces of software were compared for any differences and the both pieces of software were validated with analytical correlations as presented in literature. The plots of various parameters with variations of the angle of attack or control surface deflection have also been obtained and presented. The differences between the software solutions and the analytical results can be associated with approximations of techniques used in software (the vortex lattice method is the background theory used in both DATCOM and XFLR). Additionally, from the results, it can be concluded that XFLR is more reliable than DATCOM for longitudinal, directional, and lateral stability/control coefficients. Analyses of a Boeing 747-200 (a wide-body commercial airliner) in DATCOM and XFLR for complete stability/control analysis including all modes in the longitudinal and lateral directions have been presented. DATCOM already has a sample analysis of a previous version of the Boeing 737, however, the Boeing 747-200 is much larger than the former, and complete analysis was, therefore, felt necessary to study its aerodynamics characteristics. Furthermore, in this research, it was concluded that XFLR is more reliable for various categories of aircraft alike in terms of general stability and control coefficients, and hence many aircraft can be dependably modeled and analyzed in this software.

Early diagnosis of lung cancer plays crucial role in the improvement of patients' chances of survival. Computer aided detection (CAD) system has been a groundbreaking step in the timely diagnosis and identification of potential nodules (lesions). CAD system starts detection process by extracting lung regions from CT scan images, this step narrows down the region for detection. Hence saving the time consumption and reducing false positives outside the lung regions that results in the improvement of specificity of system. Proper lung segmentation significantly increases the performance of CAD systems. Different algorithms are presented by various researchers to improve segmentation results. An intensity based approach is presented in this paper for the segmentation of parenchyma and the goal is to achieve reasonable segmentation results in less time. Algorithm used in this paper is based on the Intensity based thresholding which is the fastest method for image segmentation. Images used in this research to analyze algorithm's result are taken from Lung Image Database Consortium (LIDC). Twenty random cases were picked, each having different number of slices (128 to 300). Algorithm is implemented using MatlabR2014 and a system with processor of 2.6 GHz and RAM of 4 GB. Total time taken for a single case of 128 images was 6.3 seconds and hence with an average of 49 milli sec/slice.

Grouping of nodules helped in the reduction of false positive rate and computational time.Shape specific morphological operations were used for the refinement of juxtavascular nodules.Intensity based, geometrical and statistical features assisted in the elimination of false positives. Display Omitted Detection of pulmonary nodule plays a significant role in the diagnosis of lung cancer in early stage that improves the chances of survival of an individual. In this paper, a computer aided nodule detection method is proposed for the segmentation and detection of challenging nodules like juxtavascular and juxtapleural nodules. Lungs are segmented from computed tomography (CT) images using intensity thresholding; brief analysis of CT image histogram is done to select a suitable threshold value for better segmentation results. Simple morphological closing is used to include juxtapleural nodules in segmented lung regions. K-means clustering is applied for the initial detection and segmentation of potential nodules; shape specific morphological opening is implemented to refine segmentation outcomes. These segmented potential nodules are then divided into six groups on the basis of their thickness and percentage connectivity with lung walls. Grouping not only helped in improving system's efficiency but also reduced computational time, otherwise consumed in calculating and analyzing unnecessary features for all nodules. Different sets of 2D and 3D features are extracted from nodules in each group to eliminate false positives. Small size nodules are differentiated from false positives (FPs) on the basis of their salient features; sensitivity of the system for small nodules is 83.33%. SVM classifier is used for the classification of large nodules, for which the sensitivity of the proposed system is 93.8% applying 10-fold cross-validation. Receiver Operating Characteristic (ROC) curve is used for the analysis of CAD system. Overall sensitivity of the system is 91.65% with 3.19 FPs per case, and accuracy is 96.22%. The system took 3.8 seconds to analyze each image.

This paper presents a non-verbal and non-facial method for effective communication of a "mechanoid robot" by conveying the emotions through gestures. This research focuses on human---robot interaction using a mechanoid robot that does not possess any anthropomorphic facial features for conveying gestures. Another feature of this research is the use of human-like smooth motion of this mechanoid robot in contrast to the traditional trapezoidal velocity profile for its communication. For conveying gestures, the connection between motion of robot and perceived emotions is established by varying the velocity and acceleration of the mechanoid structure. The selected motion parameters are changed systematically to observe the variation in perceived emotions. The perceived emotions have been further investigated using three different emotional behavior models: Russell's circumplex model of affect, Tellegen---Watson---Clark model and PAD model. Results obtained show that the designated motion parameters are linked with the change of emotions. Moreover, the emotions perceived by the user are same through all three models, validating the reliability of all the three emotional scale models and also of the emotions perceived by the user.

In this research, a novel technique for obstacle detection has been proposed. Typical obstacle avoidance and autonomous system applications make use of large number of different expensive active sensing equipment (LIDAR, RADAR, laser scanners and other sensors). While, this paper attempts to tackle the issue of obstacle detection using a relatively cost-effective set of active and passive sensors, namely a projector and monocular vision system. The proposed method makes use of grid projection on the surface for detection of stationary and moving obstacles on road with the help of assessing the deformation in grid line transformation. A host of different computer vision techniques have been utilized for grid line segmentation and detection to successfully detect obstacles and its distance from a fixed reference point. This paper examines the results of the grid projection on the object detection using different obstacle configurations to test the effectiveness of the proposed obstacle detection system.

In this work, a real-time vision-based algorithm has been developed and implemented on a flying robot, in order to detect and identify a light beacon in the presence of excessive colored noise and interference. Starting from very basic and simple image analysis techniques including color histograms, filtering techniques, and color space analyses, typical pixel-based characteristics or a model of the light beacon has been progressively established. It has been found that not only are various color space-based characteristics significant, but also the relationships between various channels across different color spaces are of great consequence, in a beacon detection problem, specifically referring to a blue light-emitting diode. A block-based search algorithm comprising of multiple thresholds and linear confidence level calculation has been implemented to search established model characteristics in real-time video image data. During implementation, once excessive noise was encountered during flight tests, a simple and low cost noise and interference filter was developed. This filter very effectively handled all noise encountered in real time. The proposed work was successfully implemented and utilized on GeorgiaTech’s participating aircraft for the International Aerial Robotics Competition by Association for Unmanned Vehicle Systems International for detection of a blue light-emitting diode problem. Major contributions of this work include establishing a multiple threshold search and detection algorithm based on not only various color channels but also their relationships and handling of as much as 40% noisy or interfered video data with successful practical implementation and demonstration of proposed approach.

Finding the location of feature points in 3D space from 2D vision data in structured environments has been done successfully for years and has been applied effectively on industrial robots. Miniature flying robots flying in unknown environments have stringent weight, space, and security constraints. For such vehicles, it has been attempted here to reduce the number of vision sensors to a single camera. At first, feature points are detected in the image using Harris corner detector, the measurements of which are then statistically corresponded across various images, using knowledge of vehicle’s pose from onboard inertial measurement unit. First approach attempted is that of ego-motion perpendicular to camera axis and acceptable results for 3D feature point locations have been achieved. Next, except for a small region around the focus of expansion, forward translations along the camera axis have also been attempted with acceptable results, which is an improvement to the previous relevant work. The 3D location map of feature points thus obtained is utilizable for trajectory planning while ensuring collision avoidance through 3D space. Reduction of vision sensors to a single camera while utilizing minimum ego-motion space for 3D feature point location is a significant contribution of this work.

In this work, the stability derivatives of a missile model have been calculated and the response of a constrained missile model was examined. Behaviour of any airborne body after getting disturbed from the equilibrium position is of paramount importance for its stability analysis. The model of missile has been made using computer software. Stability derivatives of a missile have been calculated using computational fluid dynamics. To comprehend dynamic stability, analytical solution has been proposed using Newton's Second law and Small Disturbance Theory, assuming pure pitching motion. To visualize the behaviour of missile model, graphical solution has been taken out using computer code. For having an idea how it will work in real world, a cardboard model of the missile is made and has been analysed for different applied angles of attacks. At the end the analytical and experimental results have been compared. Major contributions of this work are calculation of a method to plot time history of angle of attack of a missile after some perturbation and conduction of experiment for purpose of comparison. In future, results can be validated for wind tunnel model which will be more accurate.

This paper presents the different stages of development of flight controller for unmanned aerial vehicle (UAV) with autonomously flying capability. The main purpose of flight controller is to perform a petrol function between given GPS coordinates while maintaining a specified altitude for an assigned time and then return to its launching position without any human interaction. At first a simulated environment was designed to verify the concept. Then this was implemented on actual unmanned helicopter. In wake of the current political and security situation the need for autonomous UAVs and particularly the small scale helicopters are under consideration. However, hobby airframes used for normal radio controlled flying are not readily compatible with delicate, sophisticated and complex electronics. In addition to the hardware integration with such airframes, several other challenges such as electromagnetic interference, communication signal integrity from jammers and damping of strong vibrations were handled. The goal is to develop an autonomous UAV with self-controlled flying capabilities and above mentioned functionality. It should also fulfil the requirements to perform an adequate surveillance during any political and security situation.

Background/Objectives: To shed light on the history of development of hearing aid, along with the various pros and cons of each developed technological solution. Methods/Statistical Analysis: A historical survey has been conducted, which highlights some of the more renowned and widely deployed hearing aids within the market. The different types of hearing losses and the varying degree of assistance provided by the different technological solutions have been discussed. Over the years, the overall accuracy as well as practicality of the hearing aids have improved, ranging from cumbersome and heavy hearing aids in the early 1960-1970s to the portable and wearable ones available in the market at present. Findings: Technological innovation is spearheading massive improvement within the hearing aids. Some of the key features causing these changes include wireless technology, frequency lowering, directional microphones and digital noise reduction algorithms. Although DSP has provided significant changes in the hearing technology, limitations still exist, which require re-search contributions from different fields like clinical audiology, psychoacoustics and signal processing. Application/Improvements: Most of the portable and reliable hearing aid devices are very expensive. Therefore, there is a need to develop affordable pieces of equipment that is able to cater to basic hearing functionalities.

Background/Objectives: To construct a Pakistani sign language learning-based gesture recognition system with a reasonable rate of accuracy. Methods/Statistical Analysis: It should be

This paper presents a modified method for solving the Inverse Kinematics problem for Parallel Manipulators. The manipulator assumed consists of two 6R serial chains in parallel (biped configuration) with multiple orthogonally intersecting joint axes. The problem question is to determine whether or not is it possible to attain a certain goal configuration of the base and if yes then how to solve for the unknown joint angles. In principle this method can be extended to applications for mobile parallel manipulators with more than 2 serial chains.

This paper is about the development of control test mock-up for the radio range testing of unmanned disaster relief helicopter. The research is part of project to convert an hobby helicopter into disaster relief helicopter. Theme is to develop a ground test bench with all the servo motors and receiever circuitry and monitor the movement of servo motors in degrees with the distance to check the control. Radio control of helicopter is monitored by change in servo motors angles. Proposed test system is tested for JR transciever module to check the validity.

This work focuses on efficient and effective vision systems for object detection for ground & aerial robots venturing into unknown environments, with minimum possible vision aids onboard, i.e. a single camera. The existing approaches to solve such a problem include ‘Structures From Motion’, Optical Flows and ‘Flow Field Divergence’, etc. These approaches have been analyzed here for various constraints involved, and the Motion Estimation technique has been proposed to solve for obstacle detection problem for collision avoidance, using a single camera. This technique not only overcomes various constraints of other approaches, but also retains most of their merits. Its implementation on synthetically generated images as well as on some real videos from a UAV, has been proved successful to solve this problem. However, while implementing the technique on UAVs in actual flight, quite a few undesirable motion vectors have been encountered. An analysis of such implementation issues has been presented next, along with proposed solutions. After adequately addressing such issues, the application of this approach is being attempted on any of Georgia Tech’s aerial robotic platforms.

This paper aims at detecting obstacles using a single camera in an unknown three dimensional world, for 3D motion of an unmanned air vehicle. Obstacle detection is a pre-requisite for collision-free motion of a UAV through 3D space. Most research towards vision based obstacle detection and avoidance has been done for 2D planar motion of ground robots and using active sensors like laser range finders, sonar, radar etc. Passive camera based research has mostly been done, either using stereo vision (multiple cameras) or, by developing a prior expectation map of the world and its comparison with the new image data. In this paper, an attempt has been made to find a 3D solution of the obstacle detection problem using a single camera in an unknown world. The equations developed and the simulations results presented here, show that a 3D model of the scene can be generated from 2D image information from a single camera flying through a very small arc of lateral flight around the object, without the need of capturing images from all sides as in a typical ‘structures from motion’ problem. The forward flight simulation results show that the depth extracted from forward motion is in fact usable for large part of the image, which is a significant contribution of this work.

Much of the work in the field of aerothermodynamics focusing hypersonic vehicles is underway in different parts of the world, yet a comprehensive review of all hypersonic wind tunnel facilities is missing from literature. Current study addresses this research gap by reviewing all existing and operational hypersonic wind tunnels of the world. Aerothermodynamic vehicle has peculiar design features with varying performance parameters as they pass through different flight regimes during single flight operation. Ascent to space and reentry back into atmosphere being the two most important flight regimes any such vehicle pass through. Maximum dynamic pressure during exit for space and total heat flux going into the vehicle surface during reentry are critical measurements to be undertaken inside ground facility during initial design phase. Hypersonic regime has thermodynamic and chemical processes, which dominate energy transfer between medium and re-entry vehicle. Measurement of performance parameters remained a challenge for at least half a decade. Researchers are facing difficulties in measuring accurate and reliable data from wind tunnels conducting experiments at hypersonic speeds. The operational facilities can meet Mach and Reynolds numbers requirements but noise levels, binary scaling parameters, capturing non-equilibrium phenomenon are to name few which pose real challenge to designers of this age. This research reviews basic types of existing hypersonic wind tunnel facilities and presents a comparative study of world's famous hypersonic ground test facilities which have shown significant contribution towards research and development activities in the field of aerothermodynamics. This study will be helpful in identifying correct facility for any aerothermodynamic research to be undertaken in future. It is concluded that no real time hypersonic wind tunnel exists in world today which can be run for long durations and have all physical phenomenon of hypersonic flow. There are several technological complications still present today which includes maintaining high stagnation temperatures for long duration, large test sections, lacking of physical flow features around tested vehicle like think shock layer, entropy layer, viscous interactions and capabilities for large angle of attack parametric variation.

In order to control a Robotic arm it involves study of kinematics and dynamics. In this paper we study forward kinematics of Planer Pneumatic Robotic Arm with two prismatic and three revolute (2P-3R) joints. Forward kinematics involves computing End Effector orientation and position provided with a set of joint angles. In this paper we used Denavit Hartenberg D-H to model links and joints of the Robotic arm. Because of simplicity of design and control, reliability and safety Pneumatic robotic arm is very commonly used in industries for part handling and pick and place purpose and it is also used in laboratory for training purposes.