Development of Modeling and Simulation Platform for Path-Planning and Control of Autonomous Underwater Vehicles in Three-Dimensional Spaces

Autonomous underwater vehicles (AUVs) operating in deep sea and littoral environments have diverse applications including marine biology exploration, ocean environment monitoring, search for plane crash sites, inspection of ship-hulls and pipelines, underwater oil rig maintenance, border patrol, etc. Achieving autonomy in underwater vehicles relies on a tight integration between modules of sensing, navigation, decision-making, path-planning, trajectory tracking, and low-level control. This system integration task benefits from testing the related algorithms and techniques in a simulated environment before implementation in a physical test bed. This thesis reports on the development of a modeling and simulation platform that supports the design and testing of path planning and control algorithms in a synthetic AUV, representing a simulated version of a physical AUV. The approach allows integration between path-planners and closed-loop controllers that enable the synthetic AUV to track dynamically feasible trajectories in three-dimensional spaces. The dynamical behavior of the AUV is modeled using the equations of motion that incorporate the effects of external forces (e.g., buoyancy, gravity, hydrodynamic drag, centripetal force, Coriolis force, etc.), thrust forces, and inertial forces acting on the AUV. The equations of motion are translated into a state space formulation and the S-function feature of the Simulink and MATLAB scripts are used to evolve the state trajectories from initial conditions. A three-dimensional visualization of the resulting AUV motion is achieved by feeding the corresponding position and orientation states into an animation code. Experimental validation is carried out by performing integrated waypoint planner (e.g., using the popular A* algorithm) and PD controller implementations that allow the traversal of the synthetic AUV in two-dimensional (XY, XZ, YZ) and three-dimensional spaces. An underwater pipe-line inspection task carried out by the AUV is demonstrated in a simulated environment. The simulation testbed holds a potential to support planner and controller design for implementation in physical AUVs, thereby allowing exploration of various research topics in the field

Gender identity disorder: role of the gynecologist

Gender dysphoria refers to distress that is caused by a sense of incongruity between an individual's self-identified gender and natal sex. Over 1.4 million adults are identified as transgender. Transpatients face many barriers when it comes to basic health needs including education, housing, and health care. Because of these barriers, many patients do not receive proper health care that they need. Additionally, because of certain high-risk behaviours as well as long-term hormonal therapy, transpatients have different routine health care needs that should be addressed in the primary care setting. Diagnosis is made in accordance with the diagnostic and statistical manual of mental disorders and treatment first involves psychiatric therapy, which can help determine a patient's true goals in regards to achieving gender identity. Patients who wish to undergo transition to the opposite sex must undergo a supervised real-life test and often are treated with hormonal therapy to develop physical characteristics consistent with their gender identity. Many of these individuals have undergone, or plan to undergo, gender-affirming surgery. While not all gender-affirming surgeries are provided by obstetricians and gynecologists (OBGYNs). It is a multi-disciplinary team which involves psychiatrist, endocrinologist, gynecologist and plastic surgeon. OBGYNs are uniquely skilled to perform certain gender-affirming surgeries such as hysterectomies, bilateral oophorectomies. In this case report we discuss the medical and surgical options available for the transgender population. In addition, it also highlights the role of gynecologists in having care for this population, and should be knowledgeable about the general principles of transgender health

United States - China Relations: Prospects during Xi - Biden Tenure

Bilateral relations between China and the United States have become strategic in nature with implications to the rest of the world. Both have been engaging and competing on a number of issues in the recent times. While both seek security and stability so as to pursue their respective national interests, they differ on the way they pursue these. While engagement has been the dominant theme in the previous administrations, since late Trump, bilateral relations exhibited tensions on a number of issues including what China considered to be its core interests. Chinas agenda of keeping a low profile has been changed to accomplish something and it intends to occupy the centre stage in the long-term. The election of Joseph Biden as the President of the US coincided with the ongoing reassessments on the bilateral relations as well as coming to the fore of tensions on a number of fronts with China. The spread of COVID-19 pandemic, decline in global growth rates, disruptions in supply chains, and the growing uncertainty have only further exacerbated the US - China relations. Below is a review of the bilateral relations in the recent times by eliciting cooperative and competitive trends between China and the US. It is argued that the US - China relations are undergoing major shifts due to the tensions even as both are for ushering in strategic stability. Chinas perceptions at the leadership level, media and academic levels are outlined in brief to suggest that relations with the US are exhibiting tensions on a number of issues that pose challenges and opportunities for other countries

Design and Analysis of Centrally Suspended Cage-less Limited Slip Differential

Limited slip differential (LSD) plays an important role in maintaining speeds and in torque distribution between the wheels of the automobile even in case of variable traction. In the present project work, limited slip differential is considered and the objective of the project is to find out tangential, axial and radial forces involved in meshing of the differential gears theoretically. Finite Element Analysis (FEA) is carried out on Final, Crown, Side and Ring gears made of 20MnCr5 material and running at a speed of 4000rpm and torque of 122N-m. From the analysis, it is found that the forces and stresses obtained are below the allowable stress of the material considered in designing gears of the differential. Maximum von-Mises stress is for Ring gear and Minimum for Side gears.

Advances in Plasma Arc Welding: A Review

The nature of welding in the aeronautical industry is characterized by low unit production, high unit cost, extreme reliability and severe service conditions. These characteristics point towards more expensive and more concentrated heat sources such as plasma arc, laser beam and electron beam welding as the processes of choice for welding of critical components. Among various precision welding processes, Plasma Arc welding has gained importance in small and medium scale industries manufacturing bellows , diaphragms etc because of less expensive and easy to operate. This paper reviews the works on Plasma Arc welding and associated phenomena such as Micro Plasma Arc Welding, Variable Polarity Plasma Arc welding and Keyhole Plasma Arc Welding. The review covers works carried out by various researchers on various metals using different modes of plasma arc

Plasticity based approach for cyclic behaviour of Unreinforced Masonry

In present Thesis a plasticity based composite interface model is proposed for the simulation of cyclic behavior of the masonry under cyclic loading. The monotonic composite interface model consist of single surface yield criterion which is extension of mohr-Coulomb criteria with cut in tension region and a cap in compression region