Dynamic IBVS Control of an Underactuated UAV

Abstract-In this paper image based visual servo approach for 3D translational motion and yaw rotation of an underactuated flying robot is considered. Taking into account the complexity of dynamics of flying robots, main objective of this paper is to consider the dynamics of these robots in designing an image based control strategy. Inertial information of the robot orientation is combined with image information in order to have overall system dynamics in a fashion to apply full dynamic image based controller. Suitable perspective image moments are used in order to have satisfactory trajectories in image space and Cartesian coordinates. A nonlinear controller for the full dynamics of the system is designed. Simulation results are presented to validate the designed controller

Survival Rate of Non-Epithelial Ovarian Tumors in Iran

Background: The aim of this study was to estimate the overall survival (OS) and relapse free survival (RFS) of the non-epithelial ovarian tumors (NEOTs) of ovarian germ cell tumors (OGCT) and ovarian sex cord tumors (OSCT) in Iranian women; we also evaluated the relative prognostic factors. Method: In this retrospective study, we screened the documents of all the women diagnosed with OGCTs and OSCTs from 2012 to 2019. We further assessed the OS, RFS, and different prognostic factors. Results: A statistically significant association existed between RFS and stage of the disease at diagnosis in OSCTs group by univariate analysis and multivariate analysis (HR: 0.25 (95% CI (0.08-0.78), P=0.01) and multivariate analysis (HR: 0.27 (95% CI (0.08-0.97), P=0.04), respectively. The kaplan-meier analysis and the Log Rrank (Mantel-Cox) showed a statistically significant relationship between the stage at diagnosis and RFS in OGCT group (P=0.042). RFS was 96% for OGCT patients, and 92.7% for OSCT patients. During the follow-up, only one patient passed away in the dysgerminoma group; the OS rate was 98% for OGCT patients, and 100% for OSCT patients. Conclusion: The OS and RFS obtained in this study confirmed that the ovarian germ cell and sex cord malignancies were among the highly treatable solid tumors. Stage can be proposed as the main prognostic factor; also, larger series of studies are needed for detecting the prognostic significance of serum markers

Corrigendum: ‘Adaptive dynamic surface control of a two‐axis gimbal system’

Abstract An adaptive Dynamic Surface Controller (DSC) is designed for a two‐axis gimbal system with actuator dynamics in the presence of parametric uncertainties in [1]. A Lyapunov stability analysis is used to guarantee the convergence of the tracking error to the origin and boundedness of all closed‐loop signals. The main objective of this corrigendum is to point out several errors that occurred throughout the paper, resulting in the inaccuracy of the used dynamic model and ineffectiveness of the proposed controller. It should be noted that taking into account the corrections stated in this corrigendum, the main result of the original paper is still valid

AN ADAPTIVE SCHEME FOR IMAGE-BASED VISUAL SERVOING OF AN UNDERACTUATED UAV

An image-based visual servoing (IBVS) method is proposed for controlling the 3D translational motion and the yaw rotation of a quadrotor. The dynamic model of this unmanned aerial vehicle (UAV) is considered at the design stage to account for its underactuation. In contrast with previous IBVS methods for underactuated UAVs, which used spherical image moments as visual features, the proposed controller makes use of appropriately defined perspective moments. As a consequence, we gain a clear improvement in performance, as satisfactory trajectories are obtained in both image and Cartesian space. In addition, an adaptation mechanism is included in the controller to achieve robust performance in spite of uncertainties related to the depth of the image features and to the dynamics of the robot. Simulation results in both nominal and perturbed conditions are presented to validate the proposed method

Analitička detekcija pogreške i izolacijski algoritmi zasnovani na rotacijskim matricama za satelit s tri osi

This paper presents fault detection and isolation (FDI) algorithms for attitude determination system (ADS) of a satellite including a sun sensor and a magnetometer. The suggested methodology is based on derivation of all possible rotations between reference and body frames and computation of Euler angles by them. Using the resulted Euler angles, some variance measures have been derived that offer a solution for analytical model-free fault detection mechanism. Consequently, when significant variations occur in these variances a fault occurrence is declared. It is shown that by properly categorizing the Euler angles computation methods, not only the faulty sensors but also their faulty components could be isolated. Based on the mentioned feature, four steps of fault isolation have been proposed. In the first step, fault occurrence in only one component of a sensor is isolated. In the second step, two faults in two different sensors are investigated. In the third step, two faults in one sensor are evaluated that means a high level of failure in the sensor. Finally, if fault does not belong to the above categories, it means that more than 50% damage has been occurred in the ADS hardware. Through extensive simulation studies, the desired performance and accuracy of the outlined methods have been demonstrated.Ovaj rad prikazuje detekciju pogreške i izolacijske algoritme za sustav određivanja stanja satelita uključujući sunčani senzor i magnetometar. Predložena metodologija temelji se određivanju svih mogućih rotacija među referentnim i stvarnim koordinatnim sustavima i Eulerovim kutevima među njima. Koristeći Eulerove kutove dobivene su varijance pomoću kojih se dobiva rješenje za analitičku detekciju pogreške bez korištenja modela. U slučaju značajnih promjena varijance detektirana je pogreška. Pokazano je da se prikladnim kategoriziranjem izračuna Eulerovih kuteva uz pogreške senzora može i izolirati komponenta senzora koja je uzrokovala pogreku. Na temelju toga predlažu se četiri koraka izolacije pogreške. U prvom koraku, izolirano je postojanje pogreške u samo jednom senzoru. U drugom koraku, istražuju se dvije pogreške u dva različita senzora. U trećem koraku, promatraju se dvije pogreške u jednom senzoru što će značiti visoku razimu pogreške u senzoru. Konačno, ukoliko pogreška ne pripada niti jednoj od navedenih kategorija, to znači da je prisutno oštećenje opreme veće od 50%. Kroz opsežne simulacije prikazano je željeno ponašanje i točnost navedene metode

Dynamic IBVS control of an underactuated UAV

In this paper image based visual servo approach for 3D translational motion and yaw rotation of an under-actuated flying robot is considered. Taking into account the complexity of dynamics of flying robots, main objective of this paper is to consider the dynamics of these robots in designing an image based control strategy. Inertial information of the robot orientation is combined with image information in order to have overall system dynamics in a fashion to apply full dynamic image based controller. Suitable perspective image moments are used in order to have satisfactory trajectories in image space and Cartesian coordinates. A nonlinear controller for the full dynamics of the system is designed. Simulation results are presented to validate the designed controller. © 2012 IEEE

Design of an Extended Interacting Multiple Models Adaptive Estimator for Attitude Determination of a Stereoimagery Satellite

We will design an extended interacting multiple models adaptive estimator (EIMMAE) for attitude determination of a stereoimagery satellite. This algorithm is based on interacting multiple models (IMM) extended kalman filters (EKF) using star sensor and gyroscope data. In this method, the motion of satellite during stereoimaging manoeuvres is partitioned into two different modes: “manoeuvring motion” mode and “uniform motion” mode. The proposed algorithm will select the suitable Kalman filter structure to estimate gyro errors accurately in order to maintain the peak attitude estimation error less enough at the beginning of manoeuvres while the satellite is in “manoeuvring motion” mode and then will select the suitable star sensor measurement noise level at the end of manoeuvres while the satellite is in “uniform motion” mode to reduce attitude estimation errors. It will be shown that using the proposed algorithm, the attitude estimation accuracy of stereoimagery satellite will be increased considerably. The effectiveness of the proposed algorithm will be examined and compared with the previous proposed methods through numerical simulations

Cell type‐dependent functions of microRNA‐92a

The role of miR-17/92 family in development and progression of various cancers has been established. The members of this miRNA family have been shown to be over expressed and target various genes within proliferation, metastasis and angiogenesis pathways. Although all members might be overexpressed in a certain cancer type, only certain members of the family may have roles in progression of that cancer. In this study, we have chosen miR-92a, a member of the miR-17/92 family to compare its function in three different cancer cell lines. HL60, MCF7, and Jurkat cell lines were transduced with miR-92a and proliferation and apoptosis was measured in these cells by cell count, MTT, and caspase assays. Although in comparison to pre-miR-17/92, the level of miR-92a is higher in Jurkat cells compared to MCF7 and HL60 cells, here we have shown that increasing miR-92a levels results in apoptosis in Jurkat cells and proliferation in MCF7 and HL60 cells. miR-92a was also microinjected into mice fertilized eggs and after dissection, apoptosis was only observed in white pulp of spleen that is mainly made up of white blood cells. Our results show that miR-92a possesses a cell-type dependent function

Cell type-dependent functions of microRNA-92a

The role of miR-17/92 family in development and progression of various cancers has been established. The members of this miRNA family have been shown to be over expressed and target various genes within proliferation, metastasis and angiogenesis pathways. Although all members might be overexpressed in a certain cancer type, only certain members of the family may have roles in progression of that cancer. In this study, we have chosen miR-92a, a member of the miR-17/92 family to compare its function in three different cancer cell lines. HL60, MCF7, and Jurkat cell lines were transduced with miR-92a and proliferation and apoptosis was measured in these cells by cell count, MTT, and caspase assays. Although in comparison to pre-miR-17/92, the level of miR-92a is higher in Jurkat cells compared to MCF7 and HL60 cells, here we have shown that increasing miR-92a levels results in apoptosis in Jurkat cells and proliferation in MCF7 and HL60 cells. miR-92a was also microinjected into mice fertilized eggs and after dissection, apoptosis was only observed in white pulp of spleen that is mainly made up of white blood cells. Our results show that miR-92a possesses a cell-type dependent function