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Distributed processing tools for autonomous underwater vehicles
Title
Distributed processing tools for autonomous underwater vehicles.
Creator
Jade, Prashanth., Florida Atlantic University, Ganesan, Krishnamurthy
Abstract/Description
Software for Autonomous Underwater Vehicles (AUVs) is usually complex. It involves several complicated tasks such as controller, path planner, map builder, and sensor processor. Distributed processing is unavoidable for such a complex software system with real-time response requirements. Once these processes are distributed over several computers, it is essential that they have some mechanism to communicate to each other to share information. Each process might communicate with several of the...
Show moreSoftware for Autonomous Underwater Vehicles (AUVs) is usually complex. It involves several complicated tasks such as controller, path planner, map builder, and sensor processor. Distributed processing is unavoidable for such a complex software system with real-time response requirements. Once these processes are distributed over several computers, it is essential that they have some mechanism to communicate to each other to share information. Each process might communicate with several of the other processes. Interprocess communication becomes an important issue. This thesis discusses the design and implementation of a generic distributed toolkit that facilitates the development of distributed software for AUVs. This toolkit makes the details ofinterprocess communication transparent to the programmers involved in the AUV software development. The toolkit provides efficient direct communication between processes and does not impose any constraints on the architecture of the distributed software. Conventional techniques for monitoring/debugging of sequential programs are not applicable for distributed processes. This is because the correctness of a real-time distributed program is determined not only by its "logical" correctness but also its "timing" correctness. Monitoring mainly comprises of observation of the system during its operation. Debugging is mostly a graphical "post-mortem" analyses of the dumps generated by the distributed program. This thesis also presents the design of a window based generic graphical monitoring/ debugging tool.
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Date Issued
1992
PURL
http://purl.flvc.org/fcla/dt/14871
Subject Headings
Submersibles, Electronic data processing--Distributed processing, Real-Time data processing, Debugging in computer science
Format
Document (PDF)
Obstacle avoidance for AUVs
Title
Obstacle avoidance for AUVs.
Creator
Gan, (Linda) Huilin., Florida Atlantic University, Ganesan, Krishnamurthy
Abstract/Description
This thesis describes a general three-dimensional Obstacle Avoidance approach for the Autonomous Underwater Vehicle (AUV) using a forward-looking high-frequency active sonar system. This approach takes into account obstacle distance and AUV speed to determine the vehicle's heading, depth and speed. Fuzzy logic has been used to avoid the abrupt turn of the AUV in the presence of obstacles so that the vehicle can maneuver smoothly in the underwater environment. This approach has been...
Show moreThis thesis describes a general three-dimensional Obstacle Avoidance approach for the Autonomous Underwater Vehicle (AUV) using a forward-looking high-frequency active sonar system. This approach takes into account obstacle distance and AUV speed to determine the vehicle's heading, depth and speed. Fuzzy logic has been used to avoid the abrupt turn of the AUV in the presence of obstacles so that the vehicle can maneuver smoothly in the underwater environment. This approach has been implemented as an important part of the overall AUV software system. Using this approach, multiple objects could be differentiated automatically by the program through analyzing the sonar returns. The current vehicle state and the path of navigation of the AUV are self-adjusted depending on the location of the obstacles that are detected. A minimum safety distance is always maintained between the AUV and any object. Extensive testing of the program has been performed using several simulated AUV on-board systems undergoing different types of missions.
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Date Issued
1997
PURL
http://purl.flvc.org/fcla/dt/15451
Subject Headings
Submersibles--Automatic control, Fuzzy logic, Neural networks (Computer science)
Format
Document (PDF)
Case-based reasoning for mission planning, control, and decision-making
Title
Case-based reasoning for mission planning, control, and decision-making.
Creator
Vasudevan, Cheranellore., Florida Atlantic University, Ganesan, Krishnamurthy, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Case-based reasoning (CBR) is a powerful reasoning paradigm for many application domains like planning, diagnosis, classification, and decision making. Recognizing solutions of past instances which are similar to the problem in hand is the central concept of CBR. Accordingly, the main research issues in CBR are efficient indexing, retrieval, and evaluation of cases. Generalization of indices has been a major concern as it directly influences the size of casebases and the ability to recognize...
Show moreCase-based reasoning (CBR) is a powerful reasoning paradigm for many application domains like planning, diagnosis, classification, and decision making. Recognizing solutions of past instances which are similar to the problem in hand is the central concept of CBR. Accordingly, the main research issues in CBR are efficient indexing, retrieval, and evaluation of cases. Generalization of indices has been a major concern as it directly influences the size of casebases and the ability to recognize the right candidate cases. This dissertation work presents a novel indexing scheme--using fuzzy sets to represent case indices and fuzzy aggregation operators to evaluate case matches. The proposed scheme, REFIC (REasoning from Fuzzy Indexed Cases), provides a flexible and transparent scheme to generalize case indices leading to smaller casebases. A hierarchical aggregation of different index matches is suggested for case evaluation. Also, for continuous variable domains, it is proposed to combine the solutions of a small subset of best matching cases as opposed to the conventional approach of selecting and modifying a single best one. These schemes are demonstrated by implementing a case-based navigation planner for autonomous underwater vehicles (AUVs). This navigation planner comprises of an annotated map database, a case-based path planner, and a hybrid fuzzy-CBR based reactive navigation module. The annotated map database provides a general framework for modeling the navigational environment. Annotations attached to objects and geometrical query handling are two main features of this database. Using this system as a spatial casebase, an off-line path planning system for AUV missions is designed. The obstacle avoidance module employs CBR to dynamically select promising directions of movement and to activate a subset of navigational behaviors. This reactive navigation scheme has been found to be very robust under noisy sensor data and complex obstacle distribution patterns.
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Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/12406
Subject Headings
Case-based reasoning, Submersibles, Fuzzy sets, Index theorems
Format
Document (PDF)
Software design using case based reasoning
Title
Software design using case based reasoning.
Creator
Smith, Nancy T., Florida Atlantic University, Ganesan, Krishnamurthy, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
The project that was created for this thesis is a Case Based Reasoning application to be used in high level software design for Siemens' Telecommunications software. Currently, design engineers search for existing subtasks in the software that are similar to subtasks in their new designs by reading documentation and consulting with other engineers. The prototype for Software Design Using Case Based Reasoning (SDUCBR) stores these subtasks in a case library and enables the design engineer to...
Show moreThe project that was created for this thesis is a Case Based Reasoning application to be used in high level software design for Siemens' Telecommunications software. Currently, design engineers search for existing subtasks in the software that are similar to subtasks in their new designs by reading documentation and consulting with other engineers. The prototype for Software Design Using Case Based Reasoning (SDUCBR) stores these subtasks in a case library and enables the design engineer to locate relevant subtasks via three different indexing techniques. This thesis addresses knowledge representation and indexing mechanisms appropriate for this application. SDUCBR is domain-dependent. Cases are stored in a relational hierarchy to facilitate analyzing the existing implementation from various perspectives. The indexing mechanisms were designed to provide the software design engineer with the flexibility of describing a problem differently based on the objective, level of granularity, and special characteristics of the subtask.
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Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/15198
Subject Headings
Computer software--Development, Case-based reasoning, Artificial intelligence--Data processing, System design
Format
Document (PDF)