61 research outputs found
Fuzzy-neural control with application to a heating system
In this paper, a fuzzy-neuro approach will be presented for the design of bang-bang control system. A description of the architecture will be given. The multi-layered structure of the controller is essentially a neural network which resembles a fuzzy rule-based system. The robustness issue of an application to a heating system will also be described.published_or_final_versio
Evaluation of a low cost solid-state accelerometer as a distance measuring sensor for vehicle positioning system
This paper describes an evaluation of a low cost, solid state accelerometer as a distance-measuring device. Kalman filter was applied to reduce random noise existing in the sensor. The random bias drift of the accelerometer was found to be 2.5 mg. The accelerometer was moved back and forth eight times for a distance of 40 cm with an acceleration of 10 m/s2 and the distance error accumulated +1.55 cm. The bias drift rate due to temperature was 0.108 ΞΌg/s when the accelerometer was placed at room temperature. The performance shows that the device is suitable for short duration distance measurement and may act as a complementary sensor to the GPS during signal blockage or between periodical absolute position updates.published_or_final_versio
Tricolor light emitting diode dot matrix display system with audio output
In this paper, a novel tricolor dot matrix display system in which all the LEDs are modulated and encoded with audio information is presented. The novelty is on the concurrent use of the tricolor LEDs for simultaneous visual message display and audio signal transmission in a free space optical link. The system is comprised of a tricolor LED dot matrix display panel with an interface circuit to a computer, an audio signal transmitter, and a receiver. The system further comprises an executive program that runs on the computer for the display control of characters, decorative pattern or messages on the display panel. The receiver, combined with a speaker, is located at some distance from the display system. The receiver is designed to demodulate the optically transmitted audio information and reproduce the messages with the speaker. For modulating emission of tricolor LEDs, an oscillator is used to vary the frequency of on/off periods of the LEDs. The frequency of flicker is high enough to be indistinguishable by human eye and hence display appears to be constantly illuminated. This is a new generation of tricolor LED dot matrix display where in addition to the usual function of LED display, they concurrently provide audio broadcasting through the visible light rays transmitted by the display panel or assembly.published_or_final_versio
Design of bang-bang controller based on a fuzzy-neuro approach
A fuzzy-neuro approach for the design of bang-bang controller is presented in this paper. The approach has been used with success for the time optimal bang-bang control of a heating system. The improved bang-bang controller suppresses the oscillations often observed at the output of an on-off controller. A fuzzy system is used for the implementation of the on-off control. An extension of the fuzzy control is provided by an equivalent neural network of the fuzzy system. A test application, that of a house heating with a two-state furnace, is developed and evaluated with standard hysteresis switching, fuzzy control, and fuzzy-neuro control.published_or_final_versio
Optical wireless based on high brightness visible LEDs
This paper is on a novel use of lighting or signaling devices constructed by light-emitting diodes (LEDs). The idea is on their concurrent use for simultaneous signaling and communications. The visible light from LEDs can be modulated and encoded with audio or data signal. Hence, an LED indicator lamp or traffic light can become an information broadcasting device. Such a system made up of high brightness visible LEDs can provide the function of open space, wireless broadcasting of audio or data signal. An implemented system with experimental results is shown. A portable receiver is designed to demodulate the optically transmitted information. The distance for audio transmission of an LED traffic light can reach over 20m. The optical link employs intensity modulation with direct detection. The system is limited to line-of-sight communications. However, this concurrent use of LEDs will open up many new applications.published_or_final_versio
A realistic early-stage power grid verification algorithm based on hierarchical constraints
Power grid verification has become an indispensable step to guarantee a functional and robust chip design. Vectorless power grid verification methods, by solving linear programming (LP) problems under current constraints, enable worst-case voltage drop predictions at an early stage of design when the specific waveforms of current drains are unknown. In this paper, a novel power grid verification algorithm based on hierarchical constraints is proposed. By introducing novel power constraints, the proposed algorithm generates more realistic current patterns and provides less pessimistic voltage drop predictions. The model order reduction-based coefficient computation algorithm reduces the complexity of formulating the LP problems from being proportional to steps to being independent of steps. Utilizing the special hierarchical constraint structure, the submodular polyhedron greedy algorithm dramatically reduces the complexity of solving the LP problems from over O(k 3 m) to roughly O(k k m), where k m is the number of variables. Numerical results have shown that the proposed algorithm provides less pessimistic voltage drop prediction while at the same time achieves dramatic speedup. Β© 2011 IEEE.published_or_final_versio
Incorporating Distant Sequence Features and Radial Basis Function Networks to Identify Ubiquitin Conjugation Sites
Ubiquitin (Ub) is a small protein that consists of 76 amino acids about 8.5 kDa. In ubiquitin conjugation, the ubiquitin is majorly conjugated on the lysine residue of protein by Ub-ligating (E3) enzymes. Three major enzymes participate in ubiquitin conjugation. They are β E1, E2 and E3 which are responsible for activating, conjugating and ligating ubiquitin, respectively. Ubiquitin conjugation in eukaryotes is an important mechanism of the proteasome-mediated degradation of a protein and regulating the activity of transcription factors. Motivated by the importance of ubiquitin conjugation in biological processes, this investigation develops a method, UbSite, which uses utilizes an efficient radial basis function (RBF) network to identify protein ubiquitin conjugation (ubiquitylation) sites. This work not only investigates the amino acid composition but also the structural characteristics, physicochemical properties, and evolutionary information of amino acids around ubiquitylation (Ub) sites. With reference to the pathway of ubiquitin conjugation, the substrate sites for E3 recognition, which are distant from ubiquitylation sites, are investigated. The measurement of F-score in a large window size (β20βΌ+20) revealed a statistically significant amino acid composition and position-specific scoring matrix (evolutionary information), which are mainly located distant from Ub sites. The distant information can be used effectively to differentiate Ub sites from non-Ub sites. As determined by five-fold cross-validation, the model that was trained using the combination of amino acid composition and evolutionary information performs best in identifying ubiquitin conjugation sites. The prediction sensitivity, specificity, and accuracy are 65.5%, 74.8%, and 74.5%, respectively. Although the amino acid sequences around the ubiquitin conjugation sites do not contain conserved motifs, the cross-validation result indicates that the integration of distant sequence features of Ub sites can improve predictive performance. Additionally, the independent test demonstrates that the proposed method can outperform other ubiquitylation prediction tools
Knowledge engineering in the computer-aided design of control systems
MAID is an expert system for the computer-aided design of control systems. It is developed in conjunction with the successful application of a systematic control system design technique. The design problem has been decomposed into sub-problems, resulting in good modularity of design knowledge. Interactive design and the designer's intuition are emphasized. MAID, which acts as a designer's assistant, was developed using the expert systems development facility provided within a control system design package. The coupling of symbolic and numerical processing was carried out in a natural way.link_to_subscribed_fulltex
Multi-input, multi-output control system analysis and synthesis by singular value decomposition
A systematic procedure has been developed for the synthesis of robust regulatory control systems comprising multi-input multi-output controllers. The technique is based on singular value decomposition and results in a simple matrix-proportional-plus-integral controller. An interactive computer-aided control system package has also been developed with the systematic technique incorporated. Two design examples are given to demonstrate the systematic nature of the design approach as well as the utility of its computer software.link_to_subscribed_fulltex
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