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Articles 1 - 7 of 7
Full-Text Articles in Engineering
Instability In Self-Pulsation In Laser Diodes And Its Effect On All-Optical Synchonization, Jonathan Hyland, Gerald Farrell
Instability In Self-Pulsation In Laser Diodes And Its Effect On All-Optical Synchonization, Jonathan Hyland, Gerald Farrell
Articles
The effect of short- and long-term frequency instability in self pulsation on all-optical synchronization using a twin-section laser diode is experimentally investigated. Short-term frequency instability broadens the unlocked full width at half maximum (FWHM) of the fundamental of the rf spectrum of the self-pulsating laser diode. We show experimentally that the value of the unlocked FWHM, and thus the level of short-term instability, has a direct effect on the optical power required to maintain synchronization. A novel means of reducing the FWHM is presented based on a reflective transmission line stub connected to the absorber of the twin-section self-pulsating laser …
Comparison Of Self Pulsation In Multisection Lasers With Distributed Feedback And Intracavity Satuarable Absorbers, P. Phelan, D. Mcdonald, A. Egan, Joe Hegarty, R. O'Dowd, Gerald Farrell, S. Lingren
Comparison Of Self Pulsation In Multisection Lasers With Distributed Feedback And Intracavity Satuarable Absorbers, P. Phelan, D. Mcdonald, A. Egan, Joe Hegarty, R. O'Dowd, Gerald Farrell, S. Lingren
Articles
The authors report a comparison of the self-pulsing characteristics of two types of semiconductor laser. They show that the self-pulsing frequency of the DFB laser is decoupled from the resonance frequency. They discuss the various characteristics, their significance in relation to optical synchronisation, and use the results to suggest a possible explanation for the mechanism for self-pulsation in the DFB laser.
Fuzzy Knowledge-Based Approach To Treating Uncertainty In Inventory Control, Dobrilla Petrovic, Edward Sweeney
Fuzzy Knowledge-Based Approach To Treating Uncertainty In Inventory Control, Dobrilla Petrovic, Edward Sweeney
Articles
Inventory control in complex manufacturing environments encounters various sources of uncertainity and imprecision. This paper presents one fuzzy knowledge-based approach to solving the problem of order quantity determination, in the presence of uncertain demand, lead time and actual inventory level. Uncertain data are represented by fuzzy numbers, and vaguely defined relations between them are modeled by fuzzy if-then rules. The proposed representation and inference mechanism are verified using a large numbers of examples. The results of three representative cases are summarized. Finally a comparison between the developed fuzzy knowledge-based and traditional, probabilistic approaches is discussed.
Using Statistics In Industry - Quality Improvement Through Total Process Control, Edward Sweeney, Gordon Betteley, Neville Mettrick, David Wilson
Using Statistics In Industry - Quality Improvement Through Total Process Control, Edward Sweeney, Gordon Betteley, Neville Mettrick, David Wilson
Books/Book chapters
No abstract provided.
Model Parameter And Time Delay Estimation Using Gradient Methods, Aidan O'Dwyer, John Ringwood
Model Parameter And Time Delay Estimation Using Gradient Methods, Aidan O'Dwyer, John Ringwood
Conference papers
A number of approaches have been proposed for parameter and time delay estimation of process models in single input, single output (SISO) control systems using gradient descent algorithms; some of these approaches involve the selection of a rational polynomial that is used to approximate time delay variations. This paper takes a generalised approach to the investigation of the most appropriate choice of the rational polynomial, and the gradient descent algorithm, to be used.
An Expert System-Based Approach To Hospitality Company Diagnosis, Andrew Balfe, Peter O'Connor, Ciaran Mcdonnell
An Expert System-Based Approach To Hospitality Company Diagnosis, Andrew Balfe, Peter O'Connor, Ciaran Mcdonnell
Conference papers
This paper describes the development of a prototype Expert System-based Analysis and Diagnostic (ESAD) package for the Hotel and Catering Industry. This computerised tool aids the hospitality manager in methodically scrutinising the hotel unit and environment, combining key information with systematic reasoning. The system searches through its extensive knowledge base, investigating complicated relationships. The number of possibilities considered is increased which will broaden the depth and breadth of the analysis and therefore should improve the quality of the managers decision making.
A Frequency Domain Based Self-Tuning Pid Controller, John Ringwood, Aidan O'Dwyer
A Frequency Domain Based Self-Tuning Pid Controller, John Ringwood, Aidan O'Dwyer
Conference papers
Traditionally, both explicit and implicit self-tuning controllers have employed time domain techniques for the identification and tracking of plant and controller parameters. The use of the frequency domain provides concise information on the dynamics of the process which has led to its wide acceptance as a domain for controller design. This paper demonstrates a method employing recursive, on-line measurement of the process frequency response, with a straightforward calculation of PID controller parameters. The computational effort involved is comparable with that of a time domain technique.