Ramachandran K I

Ramachandran K I
Amrita Vishwa Vidyapeetham | AMRITA · Center for Computational Engineering and Networking (CEN)

Ph.D.

About

89
Publications
46,141
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3,367
Citations
Citations since 2017
15 Research Items
2110 Citations
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20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400

Publications

Publications (89)
Chapter
Identifying the raga of a song or music composition upon hearing when it is sung or played in an instrument is a challenging task. Generally, it takes years of rigorous training in classical music to be able to identify ragas. Machine learning algorithms can be trained to capture the raga signatures so as to classify ragas. In this paper, we attemp...
Article
Multiscale filler-reinforced composites are emerging category of advanced materials which can replace a range of conventional materials in various applications. The nanofiller reinforcement and the synergistic inclusion of nano- and micro reinforcements in the polymer matrix could generate composites that are suitable in applications where high mod...
Article
Full-text available
Condition monitoring system monitors the system degradation and it identifies common failure modes. Several sensor signals are available for monitoring the changes in system components. Vibration signal is one of the most extensively used technique for monitoring rotating components as it identifies faults before the system fails. Early fault detec...
Conference Paper
Full-text available
A unified fault-modeling approach for machines with varying capacity, rating, size is of interest in automating production facilities. Building a unified fault-model is challenging due the presence of system specific attributes in the features derived. We explore how the effect of system specific attributes from the feature vectors can be minimized...
Article
Gear box is widely employed in automobiles and industrial machines for transmitting power and torque. It is operating under various working conditions for prolonged hours increase the chance of gearbox failure. Major faults in gear systems are caused due to wear, scoring, pitting, tooth fracture etc. Gear box failure leads to increase in machine do...
Article
Full-text available
Condition based maintenance (CBM) needs data acquired during healthy and faulty conditions to develop intelligent system for fault diagnosis. However, fault injection is not allowed/possible in a highly expensive components of complex/critical systems to collect fault condition data. Therefore, proto-type/small working models are used to conduct ex...
Article
Mechanical and chemical properties of titanium alloy have led to its wide range of applications in aerospace and biomedical industries. The heat generation and its transfer from the cutting zone are critical in machining of titanium alloys. The process of transferring heat from the primary cutting zone is difficult due to poor thermal conductivity...
Article
In this paper, we describe a method for representing the acoustic similarity of a target speaker with respect to a set of known speakers as a feature for speaker verification. We propose a novel distance based representation by encoding the cosine distance between i-vectors of the utterances belonging to target speaker and reference speakers. The n...
Article
It is important to develop an intelligent tool condition monitoring system to increase productivity and promoting automation in metal cutting process. Many attempts have been made in the past to develop such systems using signals from various sensors such as dynamometer, current, accelerometer, acoustic emission, current and voltage, etc. But the s...
Article
Full-text available
To implement the tool condition monitoring system in a metal cutting process, it is necessary to have sensors which will be able to detect the tool conditions to initiate remedial action. There are different signals for monitoring the cutting process which may require different sensors and signal processing techniques. Each of these signals is capa...
Article
Gearbox is an important equipment in an automobile to transfer power from the engine to the wheels with various speed ratios. The maintenance of the gearbox is a top criterion as it is prone to a number of failures like tooth breakage and bearing cracks. Techniques like vibration monitoring have been implemented for the fault diagnosis of the gearb...
Article
Full-text available
Gear box is used in automobiles and industries for power transmission under different working conditions and applications. Failure in a gear box at unexpected time leads to increase in machine downtime and maintenance cost. In order to overcome these losses, the most effective condition monitoring technique has to be used for early detection of fau...
Article
Full-text available
Accurate measurement of heart sound and murmur parameters is of great importance in the automated analysis of phonocardiogram (PCG) signals. In this paper, we propose a novel unified PCG signal delineation and murmur classification method without the use of reference signal for automatic detection and classification of heart sounds and murmurs. The...
Conference Paper
Full-text available
High accuracy fault diagnosis systems are extremely important for effective condition based maintenance (CBM) of rotating machines. In this work, we develop a fault diagnosis system using time and frequency domain statistical features as input to a backend support vector machine (SVM) classifier. We evaluate the performance of the baseline system f...
Article
Full-text available
Titanium and its alloys are materials that exhibit unique combination of mechanical and physical properties that enable their usage in various fields. In spite of having a lot of advantages, their usage is limited because they are difficult to machine due to their inherent properties of high specific heat capacity, reactivity with tool and low ther...
Conference Paper
Phonocardiogram (PCG) segmentation is the crucial first step in automated heart sound analysis and diagnostic systems. Recently, the cardiac signals (including, electrocardiogram, phonocardiogram and photoplethysmogram) are simultaneously recorded for most cardiac signal processing applications such as cardiovascular diagnostic system, biometric au...
Article
Full-text available
Condition monitoring of any engineering system requires various faults to be introduced into the system so as to capture the intelligence by monitoring the mechanical/electrical signals from the system. For large, complex systems like the subsystem of an aircraft, introducing faults is highly expensive and therefore not advisable. This necessitates...
Article
Full-text available
Ti-6Al-4 V is extensively used in aerospace and bio-medical applications. In an automated machining environment monitoring of tool conditions is imperative. In this study, Experiments were conducted to classify the tool conditions during High Speed Machining of Titanium alloy. During the machining process, vibration signals were monitored continuou...
Conference Paper
Full-text available
Support Vector Machine (SVM) is an important machine learning algorithm widely used for the development of machine fault diagnosis systems. In this work, we use an SVM backend classifier, with statistical features in time and frequency domain as its input, for the development of a fault diagnosis system for a rotating machine. Our baseline system i...
Conference Paper
Full-text available
Cosine distance similarities with a set of reference speakers, cosine distance features (CDF), with a backend support vector machine classifier (CDF-SVM) have been explored in our earlier studies for improving the performance of speaker verification systems. Subsequently, we also investigated on its effectiveness in improving the noise robustness o...
Conference Paper
Full-text available
Speaker verification (SV) systems need to be robust to mimicked voices of target speakers as non-target trials to make them usable in critical applications. However, the performance of SV systems for mimicked voice test conditions has not been extensively explored. In an earlier work, we used Amrita SRE database to evaluate the performance of diffe...
Article
Full-text available
A robust multistage decision-based heart sound delineation (MDHSD) method is presented for automatically determining the boundaries and peaks of heart sounds (S1, S2, S3, and S4), systolic, and diastolic murmurs (early, mid, and late) and high-pitched sounds (HPSs) of the phonocardiogram (PCG) signal. The proposed MDHSD method consists of the Gauss...
Article
Full-text available
In this Letter, we explore using covariance normalization (CVN) of vital signs to improve the performance of multi-parameter patient monitors with heart rate, arterial blood pressure, respiration rate and oxygen saturation (SpO2) as its input. Our baseline system for the experiments in this work is a support vector machine classifier with a radial...
Article
Gearbox is the only medium which balances the power and torque relations for the appropriate operating conditions, at very high speeds it controls the power output of the drive unit. Its application is wide in the field of automotive and industries. Condition monitoring of gearbox access the operating condition of the gearbox components such as gea...
Conference Paper
Full-text available
Evaluating speaker recognition systems under challenging conditions with mimicked voices of target speakers as nontarget trials is very important in making decisions of its effectiveness and deployability in critical applications. The lack of a standard database is one of the bottlenecks in pursuing research in this direction. In this paper, we pre...
Article
Full-text available
Support vector machine (SVM) is a popular machine learning algorithm used extensively in machine fault diagnosis. In this paper, linear, radial basis function (RBF), polynomial, and sigmoid kernels are experimented to diagnose inter-turn faults in a 3kVA synchronous generator. From the preliminary results, it is observed that the performance of the...
Article
Full-text available
Condition based maintenance (CBM) requires continuous monitoring of mechanical/electrical signals and various operating conditions of the machine to provide maintenance decisions. However, for expensive complex systems (e.g. aerospace), inducing faults and capturing the intelligence about the system is not possible. This necessitates to have a smal...
Technical Report
Full-text available
We use similarities with people we know already as a means to enhance the speaker verification accuracy. Motivated by this, we use cosine distance similarities with a set of reference speak-ers, cosine distance features (CDF), to improve the performance of speaker verification systems for clean and additive noise test conditions. We used mel freque...
Technical Report
Full-text available
We use similarities with people we know already as a means to enhance the speaker verification accuracy. Motivated by this, we use cosine distance similarities with a set of reference speak-ers, cosine distance features (CDF), to improve the performance of speaker verification systems for clean and additive noise test conditions. We used mel freque...
Technical Report
Full-text available
We use similarities with people we know already as a means to enhance the speaker verification accuracy. Motivated by this, we use cosine distance similarities with a set of reference speak-ers, cosine distance features (CDF), to improve the performance of speaker verification systems for clean and additive noise test conditions. We used mel freque...
Conference Paper
Full-text available
Machine condition monitoring has become increasingly important in enhancing productivity, reducing maintenance cost, and casualties in mission critical applications (for example, aerospace). It may be noted that we cannot afford to miss an alarm (fault) condition in a mission critical application as the cost of a failure can be fatal and very expen...
Article
Full-text available
We use similarities with people we know already as a means to enhance the speaker verification accuracy. Motivated by this, we experiment with the use of cosine distance similarity with respect to a set of reference speakers, cosine distance features (CDF), with a backend support vector machine (CDF-SVM) classifier for speaker verification. We use...
Article
Full-text available
Detection and classification of heart murmurs play an important role in accurate diagnosis of different types of heart dysfunctions. In this paper, we present a noise-robust method for detection and classification of heart murmurs using stationary wavelet transform (SWT) and Hilbert phase envelope. The proposed method consists of five major stages:...
Article
Full-text available
Gearbox is an essential device employed in industries to vary speed and load conditions according to the requirements. More advancement in its design and operation leads to increase in industrial applications. The failure in any of the components of gearbox can lead to production loss and increase maintenance cost. The component failure has to be d...
Conference Paper
Gearbox is the core component in any automotive/industrial application and it consists of gears and gear trains to vary the speed and torque of the machine. In order to reduce the machine breakdown cost and to increase the service life it is vital to know its operating conditions frequently to find the point of defect. The vibration signals are use...
Article
Full-text available
In automated heart sound analysis and diagnosis, a set of clinically valued parameters including sound intensity, frequency content, timing, duration, shape, systolic and diastolic intervals, the ratio of the first heart sound amplitude to second heart sound amplitude (S1/S2), and the ratio of diastolic to systolic duration (D/S) is measured from t...
Conference Paper
Full-text available
Multi-parameter patient monitors (MPM) using human vital parameters, heart rate, blood pressure, respiration rate and oxygen saturation (SpO2), are extremely valuable in enhancing the health care of the patients in the intensive care unit (ICU) and general wards. Linear support vector machine (SVM) based implementations are computationally more eff...
Article
Full-text available
Multi-parameter patient monitors (MPMs) have become increasingly important in providing quality healthcare to patients. It is well known in the medical community that there exists an intrinsic relationship between different vital parameters in a healthy person, these include heart rate, blood pressure, respiration rate and oxygen saturation. For ex...
Conference Paper
This paper presents an automated PCG signal delineation method for real-time wireless cardiac health monitoring and audio-visual stethoscope applications. The proposed method comprises the steps of: preprocessing, total variation filtering, smooth energy envelope computation, peak-amplitude determination and endpoint determination. The total variat...
Conference Paper
Full-text available
Speaker Recognition is an active area of research for the last few decades for its applications in several national security, and other forensic applications. In this work, we present the details of a speaker recognition system developed using universal background model and support vector machines(UBM-SVM). We explored several techniques to improve...
Article
In rotating machines, shaft and bearing are the critical components of interest for fault diagnosis. In recent years, the application of machine learning for fault diagnosis is gaining momentum. This paper presents the fault diagnosis of shaft and bearing using support vector machine (SVM). The experiments were conducted by simulating the 12 fault...
Article
Full-text available
Multi-parameter patient monitors (MPMs) have become increasingly important in providing quality health care to patients. A high alarm accuracy (sensitivity) will need a lower threshold for alarm detection which will lead to lower no-alarm accuracy (specificity) and viceversa. MPMs when used in an intensive care unit (ICU) need to have high sensitiv...
Conference Paper
Full-text available
This paper presents the design specifications of an experimental setup capable of injecting faults in a synchronous generator to develop and test algorithms for condition based maintenance of aerospace applications. A 3 kVA alternator is designed to inject faults in the stator winding and field windings. The system is capable of injecting open and...
Article
In this paper, a finite element model has been developed to predict the effect of residual stress induced in the work material during multiple pass turning of AISI 4340 steel. Chip morphology and force variation during machining are also quantified using the FE model. Finite element model was developed using arbitrary Lagrangian-Eulerian formulatio...
Chapter
Rapid growth in production of automobiles has increased emissions. Automotive control engineers use innovative control techniques to meet the upcoming emission standards. This paper proposes a novel method of employing artificial neural network (ANN) based predictive controller design. The controller predicts the injection duration based on the inp...
Article
The design of artificial gene regulatory networks has paved way for the construction of therapeutic gene circuits that would find application in next generation gene therapy approaches. The main challenge in such designs is in selecting the appropriate genetic components to make up the circuit in order to produce the anticipated or desired behavior...
Article
The core theme of the paper is misfire detection using random forest algorithm and decision tree based machine learning models for emission minimization in gasoline passenger vehicles. The engine block vibration signals are used for misfire detection. The signal is a combination of all vibration emissions of various engine components and also conta...
Article
The studies on tool condition monitoring along with digital signal processing can be used to prevent damages on cutting tools and workpieces when the tool conditions become faulty. These studies have become more relevant in today’s context where the order realization dates are crunched and deadlines are to be met in order to catch up with the compe...
Article
Rapid growth in production of automobiles has increased emissions. Automotive control engineers use innovative control techniques to meet the upcoming emission standards. This paper proposes a novel method of employing artificial neural network (ANN) based predictive controller design. The controller predicts the injection duration based on the inp...
Article
Roller bearing is one of the most widely used elements in rotary machines. Condition monitoring of such elements is conceived as pattern recognition problem. Pattern recognition has three main phases: feature extraction, feature selection and feature classification. Histogram features can be used for fault diagnosis of roller bearing. This paper pr...
Article
Full-text available
Tool wear and tool life are the principle areas are focus in any machining activity. The production rate, surface finish of machined component and the machine condition are directly related to the tool condition. This work on tool condition monitoring delves into data mining approach to discover the hidden information available in the tool vibratio...
Article
The shaft and bearing are the most critical components in rotating machinery. Majority of problems arise from faulty bearings in turn affect the shaft. The vibration signals are widely used to determine the condition of machine elements. The vibration signals are used to extract the features to identify the status of a machine. This paper presents...
Article
Full-text available
Bearings in the machines are the major components of interest for condition monitoring. Their failure causes increase in down time and maintenance cost. A possible solution to the problem is developing an on-line condition monitoring system. The vibration characteristics can be a determining factor that will reveal the condition of the bearing part...
Article
Nanofluids are nanotechnology‐based heat transfer fluids obtained by suspending nanometer‐sized particles in conventional heat transfer fluids in a stable manner. In many of the physical phenomena such as boiling and properties such as latent heat, thermal conductivity and heat transfer coefficient, there is significant change on addition of nano...
Article
Full-text available
To maintain optimum performance throughout the service life of an engine and to exercise a tight control over emissions, misfire detection is a vital activity. The engine block vibration contains valuable hidden information regarding the operating condition of the engine. Misfire can be detected by processing the vibration signals acquired from the...
Article
An efficient predictive plan is needed for any industry because it can optimize the resources management and improve the economy plant, by reducing unnecessary costs and increasing the level of safety. A great percentage of breakdowns in the productive processes are caused for gear box, they began its deterioration from early stages, also called in...
Article
Full-text available
A large amount of hidden biological information is contained in the human genome, which is not expressed or revealed in the form of proteins; the usual end product form of gene expression. Instead, most of such information is in the form of non-coding RNAs (ncRNAs). ncRNAs correspond to genes that are transcribed, but do not get translated into pro...
Article
Misfire detection in an internal combustion engine is very crucial to maintain optimum performance throughout its service life and to reduce emissions. The vibration of the engine block contains indirect information regarding the condition of the engine. Misfire detection can be achieved by processing the vibration signals acquired from the engine...
Article
Various methods of tool condition monitoring techniques are used to control the tool wear during machining in CNC machine tools. Based on a continuous acquisition of signals with sensor systems it is possible to classify certain wear parameters by the extraction of features. Data mining approach is used to probe into the structural information hidd...
Article
Vibration signals extracted from rotating parts of machineries carries lot many information with in them about the condition of the operating machine. Further processing of these raw vibration signatures measured at a convenient location of the machine unravels the condition of the component or assembly under study. This paper deals with the effect...
Conference Paper
A photochemical reaction is initiated by a charge separation process in the reaction center (RC) complex. Major research in this regard is to analyze the light driven electron transfer and to study the response of the molecule in which the RC is embedded, stabilizing the charge separation process in photosynthesis. In research related to artificial...
Article
This paper deals with the application of fast single-shot multiclass proximal support vector machine for fault diagnosis of a gear box consisting of twenty four classes. The condition of an inaccessible gear in an operating machine can be monitored using the vibration signal of the machine measured at some convenient location and further processed...
Article
Full-text available
The wavelet transform (WT) is used to represent all possible types of transients in vibration signals generated by faults in a gear box. It is shown that the transform provides a powerful tool for condition monitoring and fault diagnosis. The vibration signal of a spur bevel gear box in different conditions is used to demonstrate the application of...
Article
Full-text available
To determine the condition of an inaccessible gear in an operating machine the vibration signal of the machine can be continuously monitored by placing a sensor close to the source of the vibrations. These signals can be further processed to extract the features and identify the status of the machine. The vibration signal acquired from the operatin...
Article
Full-text available
The condition of an inaccessible gear in an operating machine can be monitored using the vibration signal of the machine measured at some convenient location and further processed to unravel the significance of these signals. This paper deals with the effectiveness of wavelet-based features for fault diagnosis using support vector machines (SVM) an...