Organizing emergency response in the European Arctic : a comparative study of Norway, Russia, Iceland and Greenland : MARPART Project Report 5

The report examines the emergency preparedness systems in Norway, Russia, and Iceland in the Fields of Search and rescue (SAR), oil spill response, firefighting and violent action at sea. Within each country and each Field, the report introduces the main maritime emergency preparedness and response institutions With their organizational models, responsibilities and main operational patterns

Development of Robust Control Strategies for Autonomous Underwater Vehicles

The resources of the energy and chemical balance in the ocean sustain mankind in many ways. Therefore, ocean exploration is an essential task that is accomplished by deploying Underwater Vehicles. An Underwater Vehicle with autonomy feature for its navigation and control is called Autonomous Underwater Vehicle (AUV). Among the task handled by an AUV, accurately positioning itself at a desired position with respect to the reference objects is called set-point control. Similarly, tracking of the reference trajectory is also another important task. Battery recharging of AUV, positioning with respect to underwater structure, cable, seabed, tracking of reference trajectory with desired accuracy and speed to avoid collision with the guiding vehicle in the last phase of docking are some significant applications where an AUV needs to perform the above tasks. Parametric uncertainties in AUV dynamics and actuator torque limitation necessitate to design robust control algorithms to achieve motion control objectives in the face of uncertainties. Sliding Mode Controller (SMC), H / μ synthesis, model based PID group controllers are some of the robust controllers which have been applied to AUV. But SMC suffers from less efficient tuning of its switching gains due to model parameters and noisy estimated acceleration states appearing in its control law. In addition, demand of high control effort due to high frequency chattering is another drawback of SMC. Furthermore, real-time implementation of H / μ synthesis controller based on its stability study is restricted due to use of linearly approximated dynamic model of an AUV, which hinders achieving robustness. Moreover, model based PID group controllers suffer from implementation complexities and exhibit poor transient and steady-state performances under parametric uncertainties. On the other hand model free Linear PID (LPID) has inherent problem of narrow convergence region, i.e.it can not ensure convergence of large initial error to zero. Additionally, it suffers from integrator-wind-up and subsequent saturation of actuator during the occurrence of large initial error. But LPID controller has inherent capability to cope up with the uncertainties. In view of addressing the above said problem, this work proposes wind-up free Nonlinear PID with Bounded Integral (BI) and Bounded Derivative (BD) for set-point control and combination of continuous SMC with Nonlinear PID with BI and BD namely SM-N-PID with BI and BD for trajectory tracking. Nonlinear functions are used for all P,I and D controllers (for both of set-point and tracking control) in addition to use of nonlinear tan hyperbolic function in SMC(for tracking only) such that torque demand from the controller can be kept within a limit. A direct Lyapunov analysis is pursued to prove stable motion of AUV. The efficacies of the proposed controllers are compared with other two controllers namely PD and N-PID without BI and BD for set-point control and PD plus Feedforward Compensation (FC) and SM-NPID without BI and BD for tracking control. Multiple AUVs cooperatively performing a mission offers several advantages over a single AUV in a non-cooperative manner; such as reliability and increased work efficiency, etc. Bandwidth limitation in acoustic medium possess challenges in designing cooperative motion control algorithm for multiple AUVs owing to the necessity of communication of sensors and actuator signals among AUVs. In literature, undirected graph based approach is used for control design under communication constraints and thus it is not suitable for large number of AUVs participating in a cooperative motion plan. Formation control is a popular cooperative motion control paradigm. This thesis models the formation as a minimally persistent directed graph and proposes control schemes for maintaining the distance constraints during the course of motion of entire formation. For formation control each AUV uses Sliding Mode Nonlinear PID controller with Bounded Integrator and Bounded Derivative. Direct Lyapunov stability analysis in the framework of input-to-state stability ensures the stable motion of formation while maintaining the desired distance constraints among the AUVs

Special Libraries, April 1974

Volume 65, Issue 4https://scholarworks.sjsu.edu/sla_sl_1974/1003/thumbnail.jp

Is this Ship Covered?: The Intersection of Law, Geography, and Management of Sunken Military Craft

The legal framework protecting historic shipwrecks and other underwater cultural heritage in the United States is largely fragmented and not always effective. Factors that may influence the legal protection afforded a shipwreck can include the type of ship, the location of the ship, the history and age of the ship, and the ship's country of origin. Management of historic shipwrecks may be spread across both federal and state agencies and without formal protocols that establish leadership. Many of these shipwrecks are also foreign in origin and protection for those resources is frequently determined by what some consider outdated and inapposite rules of law. Fortunately, the need to protect and properly manage historic shipwrecks has received increased recognition in legislative bodies and in the courts. One of the stronger pieces of federal legislation protecting shipwrecks is the Sunken Military Craft Act, which covers sunken military ships and aircraft around the globe. Under the act, warships, naval auxiliaries, and vessels owned and operated by a government on military noncommercial service at the time of sinking are protected from unauthorized disturbance. Considering the protective benefits afforded those sunken military craft covered by the act, the research presented here was designed to assess what types of vessels fall under the definition of protected vessels. To that end, the author consulted caselaw, applicable legislation, legal authorities, and the historical record as it applied to two types of vessels--Liberty ships operating during World War II and the privateers active during the Revolutionary war and War of 1812. The evaluation concluded that the two vessel types may be covered under the act depending on the particular voyage or activity in which the vessel was engaged at the time of sinking. The research and analysis presented is also intended to inform future evaluations of ambiguous classes of vessels to determine if they meet the statutory definition of included vessels. Many historic shipwrecks face continual threats from human factors, such as commercial fishing, recreational diving, commercial salvage, and offshore energy infrastructure. The application of federal and state legislation designed to protect historic shipwrecks from these and other hazards will often depend on the particular location of the resource. To assess the risks faced from anthropogenic hazards, the author created a risk model that incorporated the threats and protections confronted by shipwrecks in federal and state waters off the coast of North Carolina. The assessment involved production of a GIS through which each shipwreck included in the analysis would be assigned a value, which was output to a Shipwreck Vulnerability Index. Particular attention was paid to foreign shipwrecks, and the analysis presented herein includes discussion of the management issues facing foreign sunken military craft located in US waters

Decision-making and problem-solving methods in automation technology

The state of the art in the automation of decision making and problem solving is reviewed. The information upon which the report is based was derived from literature searches, visits to university and government laboratories performing basic research in the area, and a 1980 Langley Research Center sponsored conferences on the subject. It is the contention of the authors that the technology in this area is being generated by research primarily in the three disciplines of Artificial Intelligence, Control Theory, and Operations Research. Under the assumption that the state of the art in decision making and problem solving is reflected in the problems being solved, specific problems and methods of their solution are often discussed to elucidate particular aspects of the subject. Synopses of the following major topic areas comprise most of the report: (1) detection and recognition; (2) planning; and scheduling; (3) learning; (4) theorem proving; (5) distributed systems; (6) knowledge bases; (7) search; (8) heuristics; and (9) evolutionary programming

Air Force Institute of Technology Research Report 2020

This Research Report presents the FY20 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs). Interested individuals may discuss ideas for new research collaborations, potential CRADAs, or research proposals with individual faculty using the contact information in this document