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Search Results: 1 - 10 of 138837 matches for " K. Kalyani "
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Supervised fuzzy C-means clustering technique for security assessment and classification in power systems
S Kalyani, K Swarup
International Journal of Engineering, Science and Technology , 2010,
Abstract: Security assessment is an important concern in planning and operation studies of an electric power system. Conventional method of security evaluation is performed by simulation consisting of load flow program and transient stability analysis, consuming long computer time and generating voluminous results. This paper presents a practical Pattern Recognition (PR) approach for security assessment in power systems. The problem of security assessment is focused in two modes, viz., static and transient. Static security pertains to the study of violation of system components when subjected to contingencies like line/generator outages. Transient Security study deals with system dynamic behavior when subjected to severe perturbations like three phase faults. A Supervised Fuzzy C-Means (SFCM) algorithm is proposed in the classification phase of PR system for security assessment. The proposed algorithm is tested on 39 Bus New England and IEEE 57 Bus systems. The classification results of the proposed SFCM classifier is compared with the Method of Least Squares (MLS) and Multilayer Perceptron (MLP) classifiers. The results prove that the former gives high classification accuracy and less misclassification rate compared to the latter, enhancing the feasibility and applicability of SFCM algorithm for on-line security evaluation.
STUDY OF NEURAL NETWORK MODELS FOR SECURITY ASSESSMENT IN POWER SYSTEMS
S. KALYANI and K. SHANTI SWARUP
International Journal of Research and Reviews in Applied Sciences , 2009,
Abstract:
Use of Student Response Systems for Summative Assessments  [PDF]
Kalyani Premkumar
Creative Education (CE) , 2016, DOI: 10.4236/ce.2016.713187
Abstract: Student Response Systems (Clickers) have been adopted by a number of instructors to increase interactions, student engagement and/or formative assessment and feedback especially in large group sessions. Clickers are well known as tools for active learning strategy particularly in formative assessments. However, they are rarely used in assessments that count. With the advent of clickers with a display screen, attempts are being made to use clickers in summative exams. We examined the feasibility of their use in high stakes summative assessment by piloting such an assessment in a simulated setting. Utilizing the lessons learned in the pilot study, clickers were used in formative and summative assessments in various iterations of a computer course taught by one of the authors (CC). At the end of the course, perceptions of students on the use of clickers for high-stake examinations were obtained using an online survey. The instructor was interviewed to identify factors that facilitated clicker use and the challenges faced. In general, students were accepting of the use of this technology in high stakes exams and found it engaging and satisfying, primarily because of instant feedback. The instructor found the process less time consuming and efficient, and more secure compared to scan sheets. Clickers are best used for examinations of short duration, with multiple-choice questions or questions with minimal text or mathematical entry.
Transform Coefficient Histogram and Edge Preserving Image Enhancement Using Contrast Entropy
K. Sundar Srinivas,K. Naga Lakshmi Kalyani
International Journal of Computer Technology and Applications , 2011,
Abstract: Enhancing an image in such a way that maintains image edges is a difficult problem. Many current methods for image enhancement either smooth edges on a small scale while improving contrast on a global scale or enhance edges on a large scale while amplifying noise on a small scale. Many applications of histograms for the purposes of image processing are well known. However, applying this process to the transform domain by way of a transform coefficient histogram has not yet been fully explored. This paper proposes three methods of image enhancement: a) logarithmic transform histogram matching, b) logarithmic transform histogram shifting, and c) logarithmic transform histogram shaping using Gaussian distributions. They are based on the properties of the logarithmic transform domain histogram and histogram equalization. The presented algorithms use the fact that the relationship between stimulus and perception is logarithmic and afford a marriage between enhancement qualities and computational efficiency. A human visual system based quantitative measurement of image contrast improvement is also defined. This helps choose the best parameters and transform for each enhancement. A number of experimental results are presented to illustrate the performance of the proposed algorithms
Rate Prediction and Selection in LTE systems using Modified Source Encoding Techniques
K. P. Saishankar,Sheetal Kalyani,K. Narendran
Computer Science , 2014,
Abstract: In current wireless systems, the base-Station (eNodeB) tries to serve its user-equipment (UE) at the highest possible rate that the UE can reliably decode. The eNodeB obtains this rate information as a quantized feedback from the UE at time n and uses this, for rate selection till the next feedback is received at time n + {\delta}. The feedback received at n can become outdated before n + {\delta}, because of a) Doppler fading, and b) Change in the set of active interferers for a UE. Therefore rate prediction becomes essential. Since, the rates belong to a discrete set, we propose a discrete sequence prediction approach, wherein, frequency trees for the discrete sequences are built using source encoding algorithms like Prediction by Partial Match (PPM). Finding the optimal depth of the frequency tree used for prediction is cast as a model order selection problem. The rate sequence complexity is analysed to provide an upper bound on model order. Information-theoretic criteria are then used to solve the model order problem. Finally, two prediction algorithms are proposed, using the PPM with optimal model order and system level simulations demonstrate the improvement in packet loss and throughput due to these algorithms.
Syllable Analysis to Build a Dictation System in Telugu language
N. Kalyani,Dr K. V. N. Sunitha
International Journal of Computer Science and Information Security , 2009,
Abstract: In recent decades, Speech interactive systems gained increasing importance. To develop Dictation System like Dragon for Indian languages it is most important to adapt the system to a speaker with minimum training. In this paper we focus on the importance of creating speech database at syllable units and identifying minimum text to be considered while training any speech recognition system. There are systems developed for continuous speech recognition in English and in few Indian languages like Hindi and Tamil. This paper gives the statistical details of syllables in Telugu and its use in minimizing the search space during recognition of speech. The minimum words that cover maximum syllables are identified. This words list can be used for preparing a small text which can be used for collecting speech sample while training the dictation system. The results are plotted for frequency of syllables and the number of syllables in each word. This approach is applied on the CIIL Mysore text corpus which is of 3 million words.
Syllable Analysis to Build a Dictation System in Telugu language
N. Kalyani,Dr K. V. N. Sunitha
Computer Science , 2010,
Abstract: In recent decades, Speech interactive systems gained increasing importance. To develop Dictation System like Dragon for Indian languages it is most important to adapt the system to a speaker with minimum training. In this paper we focus on the importance of creating speech database at syllable units and identifying minimum text to be considered while training any speech recognition system. There are systems developed for continuous speech recognition in English and in few Indian languages like Hindi and Tamil. This paper gives the statistical details of syllables in Telugu and its use in minimizing the search space during recognition of speech. The minimum words that cover maximum syllables are identified. This words list can be used for preparing a small text which can be used for collecting speech sample while training the dictation system. The results are plotted for frequency of syllables and the number of syllables in each word. This approach is applied on the CIIL Mysore text corpus which is of 3 million words.
Spectrum Allocation for ICIC Based Picocell
Suman Kumar,Sheetal Kalyani,K. Giridhar
Computer Science , 2014,
Abstract: In this work, we analytically study the impact of spectrum allocation scheme in picocells on the coverage probability (CP) of the Pico User (PU), when the macro base stations (MBSs) employ either fractional frequency reuse (FFR) or soft frequency reuse (SFR). Assuming a fixed size for the picocell, the CP expression is derived for a PU present in either a FFR or SFR based deployment, and when the PU uses either the centre or the edge frequency resources. Based on these expressions, we propose two possible frequency allocation schemes for the picocell when FFR is employed by the macrocell. The CP and the average rate expressions for both these schemes are derived, and it is shown that these schemes outperform the conventional scheme where no inter-cell interference coordination (ICIC) is assumed. The impact of both schemes on the macro-user performance is also analysed. When SFR is used by the MBS, it is shown that the CP is maximized when the PU uses the same frequency resources as used by the centre region.
Optimal Thresholds for Coverage and Rate in FFR Schemes for Planned Cellular Networks
Suman Kumar,Sheetal Kalyani,K. Giridhar
Computer Science , 2014,
Abstract: Fractional frequency reuse (FFR) is an inter-cell interference coordination scheme that is being actively researched for emerging wireless cellular networks. In this work, we consider hexagonal tessellation based planned FFR deployments, and derive expressions for the coverage probability and normalized average rate for the downlink. In particular, given reuse $\frac{1}{3}$ (FR$3$ ) and reuse $1$ (FR$1$) regions, and a Signal-to-Interference-plus-noise-Ratio (SINR) threshold $S_{th}$ which decides the user assignment to either the FR$1$ or FR$3$ regions, we theoretically show that: $(i)$ The optimal choice of $S_{th}$ which maximizes the coverage probability is $S_{th} = T$, where $T$ is the required target SINR (for ensuring coverage), and $(ii)$ The optimal choice of $S_{th}$ which maximizes the normalized average rate is given by the expression $S_{th}=\max(T, T')$, where $T'$ is a function of the path loss exponent and the fade parameters. For the optimal choice of $S_{th}$, we show that FFR gives a higher rate than FR$1$ and a better coverage probability than FR$3$. The impact of frequency correlation over the sub-bands allocated to the FR$1$ and FR$3$ regions is analysed, and it is shown that correlation decreases the average rate of the FFR network. Numerical results are provided, and these match with the analytical results.
DEVELOPMENT OF A CHEST FREEZER – OPTIMUM DESIGN OF AN EVAPORATOR COIL
K. Kalyani Radha,S. Naga Sarada,K. Rajagopal
International Journal of Automotive and Mechanical Engineering , 2012,
Abstract: In a country such as India, food grains, fruit, vegetables, meat, poultry and fish, are very susceptible to microbial contamination and spoilage and require stringent preservation methods. One such method is by the use of a chest freezer for the storage of frozen food. This investigation considers different loads and design parameters for the development of a chest freezer using R134a as the working fluid. Experimental designs of an evaporator coil, condenser coil and capillary tube are investigated through the development of storage periods in terms of steady state and cyclic performance, by optimising the quantity of refrigerant charge, with strict adherence to the standards and requirement for maintaining an internal temperature of -23 °C at 43 °C ambient. Cyclic load performance tests optimise the performance of individual components selected for the design of a chest freezer. The system selection has a highly balanced performance with R134a and showed 118 kJ/kg cooling capacity with 8.42 coefficient of performance (COP). By the replacement of R134a, temperatures of -23 °C are maintained inside the freezer cabinet with low power consumption and an increase in the net refrigerating effect, which in turn increases the COP. The system design has optimum efficiency with moderate costs by optimising the length and diameter of the evaporator coil, i.e., 34.15 m and 7.94 mm, respectively.
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