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Selection of manufacturing tolerances for open-chain mechanisms
Title
Selection of manufacturing tolerances for open-chain mechanisms.
Creator
Kumar, Arun., Florida Atlantic University, Masory, Oren, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Flexible manufacturing systems play an important role in modern industries. The equipment used in flexible manufacturing systems such as industrial robots, NC machines, conveyors etc. demand high performance and accuracies. The selection of manufacturing tolerances is critical in deciding the accuracy of the mechanism and the manufacturing cost. In the present work a new kinematic model for open-chain mechanism is proposed which will help the designer in selecting the manufacturing tolerances...
Show moreFlexible manufacturing systems play an important role in modern industries. The equipment used in flexible manufacturing systems such as industrial robots, NC machines, conveyors etc. demand high performance and accuracies. The selection of manufacturing tolerances is critical in deciding the accuracy of the mechanism and the manufacturing cost. In the present work a new kinematic model for open-chain mechanism is proposed which will help the designer in selecting the manufacturing tolerances. The model allows the designer to estimate the manufacturing cost for the required accuracy. By using the model and the cost function, a set of tolerances can be estimated to achieve the required accuracy and/or manufacturing cost. The end point location and the manufacturing cost of the mechanism are expressed as a functions of tolerances and major dimensions. By using these expressions one can optimize the tolerances based on (1) optimizing accuracy under the cost constraint, (2) optimizing cost under the accuracy constraint.
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Date Issued
1992
PURL
http://purl.flvc.org/fcla/dt/14814
Subject Headings
Tolerance (Engineering), Machinery, Kinematics of
Format
Document (PDF)
Resilient system design and efficient link management for the wireless communication of an ocean current turbine test bed
Title
Resilient system design and efficient link management for the wireless communication of an ocean current turbine test bed.
Creator
Marcus, Anthony M., Cardei, Ionut E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
To ensure that a system is robust and will continue operation even when facing disruptive or traumatic events, we have created a methodology for system architects and designers which may be used to locate risks and hazards in a design and enable the development of more robust and resilient system architectures. It uncovers design vulnerabilities by conducting a complete exploration of a systems’ component operational state space by observing the system from multi-dimensional perspectives and...
Show moreTo ensure that a system is robust and will continue operation even when facing disruptive or traumatic events, we have created a methodology for system architects and designers which may be used to locate risks and hazards in a design and enable the development of more robust and resilient system architectures. It uncovers design vulnerabilities by conducting a complete exploration of a systems’ component operational state space by observing the system from multi-dimensional perspectives and conducts a quantitative design space analysis by means of probabilistic risk assessment using Bayesian Networks. Furthermore, we developed a tool which automated this methodology and demonstrated its use in an assessment of the OCTT PHM communication system architecture. To boost the robustness of a wireless communication system and efficiently allocate bandwidth, manage throughput, and ensure quality of service on a wireless link, we created a wireless link management architecture which applies sensor fusion to gather and store platform networked sensor metrics, uses time series forecasting to predict the platform position, and manages data transmission for the links (class based, packet scheduling and capacity allocation). To validate our architecture, we developed a link management tool capable of forecasting the link quality and uses cross-layer scheduling and allocation to modify capacity allocation at the IP layer for various packet flows (HTTP, SSH, RTP) and prevent congestion and priority inversion. Wireless sensor networks (WSN) are vulnerable to a plethora of different fault types and external attacks after their deployment. To maintain trust in these systems and increase WSN reliability in various scenarios, we developed a framework for node fault detection and prediction in WSNs. Individual wireless sensor nodes sense characteristics of an object or environment. After a smart device successfully connects to a WSN’s base station, these sensed metrics are gathered, sent to and stored on the device from each node in the network, in real time. The framework issues alerts identifying nodes which are classified as faulty and when specific sensors exceed a percentage of a threshold (normal range), it is capable of discerning between faulty sensor hardware and anomalous sensed conditions. Furthermore we developed two proof of concept, prototype applications based on this framework.
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Date Issued
2013
PURL
http://purl.flvc.org/fau/fd/FA0004035
Subject Headings
Fault tolerance (Engineering), Reliability (Engineering), Sensor networks -- Security measures, Systems engineering, Wireless communication systems -- Technological innovations
Format
Document (PDF)
Fault tolerance and reliability patterns
Title
Fault tolerance and reliability patterns.
Creator
Buckley, Ingrid A., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
The need to achieve dependability in critical infrastructures has become indispensable for government and commercial enterprises. This need has become more necessary with the proliferation of malicious attacks on critical systems, such as healthcare, aerospace and airline applications. Additionally, due to the widespread use of web services in critical systems, the need to ensure their reliability is paramount. We believe that patterns can be used to achieve dependability. We conducted a...
Show moreThe need to achieve dependability in critical infrastructures has become indispensable for government and commercial enterprises. This need has become more necessary with the proliferation of malicious attacks on critical systems, such as healthcare, aerospace and airline applications. Additionally, due to the widespread use of web services in critical systems, the need to ensure their reliability is paramount. We believe that patterns can be used to achieve dependability. We conducted a survey of fault tolerance, reliability and web service products and patterns to better understand them. One objective of our survey is to evaluate the state of these patterns, and to investigate which standards are being used in products and their tool support. Our survey found that these patterns are insufficient, and many web services products do not use them. In light of this, we wrote some fault tolerance and web services reliability patterns and present an analysis of them.
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Date Issued
2008
PURL
http://purl.flvc.org/FAU/166447
Subject Headings
Fault-tolerant computing, Computer software, Reliability, Reliability (Engineering), Computer programs
Format
Document (PDF)
Towards a methodology for building reliable systems
Title
Towards a methodology for building reliable systems.
Creator
Buckley, Ingrid A., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Reliability is a key system characteristic that is an increasing concern for current systems. Greater reliability is necessary due to the new ways in which services are delivered to the public. Services are used by many industries, including health care, government, telecommunications, tools, and products. We have defined an approach to incorporate reliability along the stages of system development. We first did a survey of existing dependability patterns to evaluate their possible use in...
Show moreReliability is a key system characteristic that is an increasing concern for current systems. Greater reliability is necessary due to the new ways in which services are delivered to the public. Services are used by many industries, including health care, government, telecommunications, tools, and products. We have defined an approach to incorporate reliability along the stages of system development. We first did a survey of existing dependability patterns to evaluate their possible use in this methodology. We have defined a systematic methodology that helps the designer apply reliability in all steps of the development life cycle in the form of patterns. A systematic failure enumeration process to define corresponding countermeasures was proposed as a guideline to define where reliability is needed. We introduced the idea of failure patterns which show how failures manifest and propagate in a system. We also looked at how to combine reliability and security. Finally, we defined an approach to certify the level of reliability of an implemented web service. All these steps lead towards a complete methodology.
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3342037
Subject Headings
Computer software, Reliability, Reliability (Engineering), Computer programs, Fault-tolerant computing
Format
Document (PDF)