Now showing items 14-28 of 28
| Abstract: | Refiners today operate their equipment for prolonged periods without shutdown. This is primarily due to the increased pressures of the market resulting in extended shutdown-to-shutdown intervals. This places extreme demands on the reliability of the plant equipment. The traditional methods of reliability assurance, like Preventive Maintenance, Predictive Maintenance and Condition Based Maintenance become inadequate in the face of such demands. The alternate approaches to reliability improvement, being adopted the world over are implementation of RCFA programs and Reliability Centered Maintenance. However refiners and process plants find it difficult to adopt this standardized methodology of RCM mainly due to the complexity and the large amount of analysis that needs to be done, resulting in a long drawn out implementation, requiring the services of a number of skilled people. These results in either an implementation restricted to only few equipment or alternately, one that is non-standard. The paper presents the current models in use, the core requirements of a standard RCM model, the alternatives to classical RCM, limitations in the existing model, classical RCM and available alternatives to RCM and will then go on to present an ‗Accelerated‘ approach to RCM implementation, that, while ensuring close conformance to the standard, does not place a large burden on the implementers |
| Description: | INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 2, ISSUE 5, MAY 2013 |
| URI: | http://dyuthi.cusat.ac.in/purl/4499 |
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| A-New-Model-For ... n-Petroleum-Refineries.pdf | (534.9Kb) |
| Abstract: | This paper presents the design and analysis of a novel machine family—the enclosed-rotor Halbach-array permanentmagnet brushless dcmotors for spacecraft applications. The initial design, selection of major parameters, and air-gap magnetic flux density are estimated using the analytical model of the machine. The proportion of the Halbach array in the machine is optimized using finite element analysis to obtain a near-trapezoidal flux pattern. The machine is found to provide uniform air-gap flux density along the radius, thus avoiding circulating currents in stator conductors and thereby reducing torque ripple. Furthermore, the design is validated with experimental results on a fabricated machine and is found to suit the design requirements of critical spacecraft applications |
| Description: | IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 59, NO. 9, SEPTEMBER 2012 |
| URI: | http://dyuthi.cusat.ac.in/purl/4481 |
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| A Novel Slotles ... pacecraft Applications.pdf | (752.8Kb) |
| Abstract: | This paper presents the design and analysis of a novel machine family of Siotiess Permanent Magnet Brushless DC motors (PMBLDC) for precise positioning applications of spacecrafts. Initial design, selection of major parameters and air gap magnetic flux density are estimated using the analytical model of the machine. The proportion of the halbach array in the machine was optimized using FE to obtain near trapezoidal flux pattern. The novel machine topology is found to deliver high torque density, high efficiency, zero cogging torque, better positional stability, high torque to inertia ratio and zero magnetic stiction suiting space requirements. The machine provides uniform air gap flux density along the radius thus avoiding circulating currents in stator conductors and hence reducing torque ripple |
| Description: | Communication Control and Computing Technologies (ICCCCT), 2010 IEEE International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4501 |
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| A Novel Slotles ... ositioningApplications.pdf | (1.450Mb) |
| Abstract: | This paper presents the optimal design of a surface mounted permanent-magnet (PM) Brushless direct-current (BLDC) motor meant for spacecraft applications. The spacecraft applications requires the choice of a motor with high torque density, minimum cogging torque, better positional stability and high torque to inertia ratio. Performance of two types of machine configurations viz Slotted PMBLDC and Slotless PMBLDC with Halbach array are compared with the help of analytical and finite element (FE) methods. It is found that unlike a Slotted PMBLDC motor, the Slotless type with Halbach array develops zero cogging torque without reduction in the developed torque. Moreover, the machine being coreless provides high torque to inertia ratio and zero magnetic stiction |
| Description: | Emerging Trends in Electrical and Computer Technology (ICETECT), 2011 International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4492 |
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| Optimal Design ... pacecraft Applications.pdf | (1.618Mb) |
| Abstract: | IT and related services played a major role for India’s current 9.2. GDP growth. Organized retailing in India is one more example for its open economy. The IT industries where able develop a demand for Indian talents all over the world and improved their living standards. It directly impacts only a small minority of Indian population while organized retail affects every single Indian and every sector of Indian society. The paper gives a glimpse of the slow evolution of retail market over the years in India and its contribution for economic growth. The likely positive impact of this revolution in different sectors is enumerated. Paper addresses its ability to manipulate consumption pattern of society, increased customer satisfaction and likely change in the market shares of the different types of sellers. Paper discusses its flip sides like increasing social tension among families below poverty line and greater loss of self employment opportunities by this revolution. The main theme of enquiry of this paper is what it all means for the Indian society. |
| Description: | International Marketing Conference on Marketing & Society, 8-10 April, 2007, IIMK |
| URI: | http://dyuthi.cusat.ac.in/purl/4482 |
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| Organized Retai ... and the Indian Society.pdf | (216.9Kb) |
| Abstract: | Modeling nonlinear systems using Volterra series is a century old method but practical realizations were hampered by inadequate hardware to handle the increased computational complexity stemming from its use. But interest is renewed recently, in designing and implementing filters which can model much of the polynomial nonlinearities inherent in practical systems. The key advantage in resorting to Volterra power series for this purpose is that nonlinear filters so designed can be made to work in parallel with the existing LTI systems, yielding improved performance. This paper describes the inclusion of a quadratic predictor (with nonlinearity order 2) with a linear predictor in an analog source coding system. Analog coding schemes generally ignore the source generation mechanisms but focuses on high fidelity reconstruction at the receiver. The widely used method of differential pnlse code modulation (DPCM) for speech transmission uses a linear predictor to estimate the next possible value of the input speech signal. But this linear system do not account for the inherent nonlinearities in speech signals arising out of multiple reflections in the vocal tract. So a quadratic predictor is designed and implemented in parallel with the linear predictor to yield improved mean square error performance. The augmented speech coder is tested on speech signals transmitted over an additive white gaussian noise (AWGN) channel. |
| Description: | Communications and Signal Processing (ICCSP), 2011 International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4500 |
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| Quadratic Predi ... ding of Speech Signals.pdf | (884.9Kb) |
| Abstract: | The Towed Array electronics is a multi-channel simultaneous real time high speed data acquisition system. Since its assembly is highly manpower intensive, the costs of arrays are prohibitive and therefore any attempt to reduce the manufacturing, assembly, testing and maintenance costs is a welcome proposition. The Network Based Towed Array is an innovative concept and its implementation has remarkably simplified the fabrication, assembly and testing and revolutionised the Towed Array scenario. The focus of this paper is to give a good insight into the Reliability aspects of Network Based Towed Array. A case study of the comparison between the conventional array and the network based towed array is also dealt with |
| Description: | Ocean Electronics (SYMPOL), 2013 |
| URI: | http://dyuthi.cusat.ac.in/purl/4497 |
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| Re-Engineering ... work Based Towed Array.pdf | (639.1Kb) |
| Abstract: | Reinforcement Learning (RL) refers to a class of learning algorithms in which learning system learns which action to take in different situations by using a scalar evaluation received from the environment on performing an action. RL has been successfully applied to many multi stage decision making problem (MDP) where in each stage the learning systems decides which action has to be taken. Economic Dispatch (ED) problem is an important scheduling problem in power systems, which decides the amount of generation to be allocated to each generating unit so that the total cost of generation is minimized without violating system constraints. In this paper we formulate economic dispatch problem as a multi stage decision making problem. In this paper, we also develop RL based algorithm to solve the ED problem. The performance of our algorithm is compared with other recent methods. The main advantage of our method is it can learn the schedule for all possible demands simultaneously. |
| Description: | TENCON 2008-2008 IEEE Region 10 Conference |
| URI: | http://dyuthi.cusat.ac.in/purl/4480 |
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| A Reinforcement ... ng Transmission Losses.pdf | (265.1Kb) |
| Abstract: | This paper presents Reinforcement Learning (RL) approaches to Economic Dispatch problem. In this paper, formulation of Economic Dispatch as a multi stage decision making problem is carried out, then two variants of RL algorithms are presented. A third algorithm which takes into consideration the transmission losses is also explained. Efficiency and flexibility of the proposed algorithms are demonstrated through different representative systems: a three generator system with given generation cost table, IEEE 30 bus system with quadratic cost functions, 10 generator system having piecewise quadratic cost functions and a 20 generator system considering transmission losses. A comparison of the computation times of different algorithms is also carried out. |
| Description: | Electrical Power and Energy Systems 33 (2011) 836–845 |
| URI: | http://dyuthi.cusat.ac.in/purl/4484 |
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| Reinforcement L ... nomic Dispatch problem.pdf | (311.8Kb) |
| Abstract: | This paper presents a Reinforcement Learning (RL) approach to economic dispatch (ED) using Radial Basis Function neural network. We formulate the ED as an N stage decision making problem. We propose a novel architecture to store Qvalues and present a learning algorithm to learn the weights of the neural network. Even though many stochastic search techniques like simulated annealing, genetic algorithm and evolutionary programming have been applied to ED, they require searching for the optimal solution for each load demand. Also they find limitation in handling stochastic cost functions. In our approach once we learn the Q-values, we can find the dispatch for any load demand. We have recently proposed a RL approach to ED. In that approach, we could find only the optimum dispatch for a set of specified discrete values of power demand. The performance of the proposed algorithm is validated by taking IEEE 6 bus system, considering transmission losses |
| Description: | Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008 |
| URI: | http://dyuthi.cusat.ac.in/purl/4490 |
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| A Reinforcement ... using Neural Networks.pdf | (165.9Kb) |
| Abstract: | Unit Commitment Problem (UCP) in power system refers to the problem of determining the on/ off status of generating units that minimize the operating cost during a given time horizon. Since various system and generation constraints are to be satisfied while finding the optimum schedule, UCP turns to be a constrained optimization problem in power system scheduling. Numerical solutions developed are limited for small systems and heuristic methodologies find difficulty in handling stochastic cost functions associated with practical systems. This paper models Unit Commitment as a multi stage decision making task and an efficient Reinforcement Learning solution is formulated considering minimum up time /down time constraints. The correctness and efficiency of the developed solutions are verified for standard test systems |
| Description: | International J. of Recent Trends in Engineering and Technology, Vol. 3, No. 3, May 2010 |
| URI: | http://dyuthi.cusat.ac.in/purl/4489 |
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| Reinforcement L ... through pursuit method.pdf | (568.2Kb) |
| Abstract: | Unit commitment is an optimization task in electric power generation control sector. It involves scheduling the ON/OFF status of the generating units to meet the load demand with minimum generation cost satisfying the different constraints existing in the system. Numerical solutions developed are limited for small systems and heuristic methodologies find difficulty in handling stochastic cost functions associated with practical systems. This paper models Unit Commitment as a multi stage decision task and Reinforcement Learning solution is formulated through one efficient exploration strategy: Pursuit method. The correctness and efficiency of the developed solutions are verified for standard test systems |
| Description: | Advances in Computing, Control, & Telecommunication Technologies, 2009. ACT'09. International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4494 |
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| Reinforcement L ... through pursuit method.pdf | (300.8Kb) |
| Abstract: | Now a days, email has become the most widely communication way in daily life. The main reason for using email is probably because of the convenience and speed in which it can be transmitted irrespective of geographical distances. To improve security and efficiency of email system, most of the email system adopt PKI and IBE encryption schemes. However, both PKI and IBE encryption schemes have their own shortcomings and consequently bring security issues to email systems. This paper proposes a new secure email system based on IBE which combines finger print authentication and proxy service for encryption and decryption |
| Description: | International Journal of Wireless Communications and Networking Technologies,Volume 1, No.1, August- September 2012 |
| URI: | http://dyuthi.cusat.ac.in/purl/4498 |
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| A Secure Email ... ntity Based Encryption.pdf | (80.09Kb) |
| Abstract: | Short term load forecasting is one of the key inputs to optimize the management of power system. Almost 60-65% of revenue expenditure of a distribution company is against power purchase. Cost of power depends on source of power. Hence any optimization strategy involves optimization in scheduling power from various sources. As the scheduling involves many technical and commercial considerations and constraints, the efficiency in scheduling depends on the accuracy of load forecast. Load forecasting is a topic much visited in research world and a number of papers using different techniques are already presented. The accuracy of forecast for the purpose of merit order dispatch decisions depends on the extent of the permissible variation in generation limits. For a system with low load factor, the peak and the off peak trough are prominent and the forecast should be able to identify these points to more accuracy rather than minimizing the error in the energy content. In this paper an attempt is made to apply Artificial Neural Network (ANN) with supervised learning based approach to make short term load forecasting for a power system with comparatively low load factor. Such power systems are usual in tropical areas with concentrated rainy season for a considerable period of the year |
| Description: | Power, Signals, Controls and Computation (EPSCICON), 2012 International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4488 |
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| Short-Term Load ... ive Learning Algorithm.pdf | (978.7Kb) |
| Abstract: | The papersummarizesthedesignandimplementationofaquadraticedgedetection filter basedon Volterraseries.The filter isemployedinanunsharpmaskingschemeforenhancing fingerprints inadark and noisybackground.Theproposed filter canaccountformuchofthepolynomialnonlinearities inherent intheinputimageandcanreplacetheconventionaledgedetectorslikeLaplacian,LoG,etc.The application ofthenew filter isinforensicinvestigationwhereenhancementandidentification oflatent fingerprints arekeyissues.Theenhancementofimagesbytheproposedmethodissuperiortothatwith unsharp maskingschemeemployingconventional filters intermsofthevisualquality,thenoise performance and the computational complexity,making it an ideal candidate for latent fingerprint enhancement. |
| Description: | PatternRecognition46(2013)3198–3207 |
| URI: | http://dyuthi.cusat.ac.in/purl/4496 |
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| Unsharpmaskingu ... rintsinnoisybackground.pdf | (9.340Mb) |
Now showing items 14-28 of 28
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