Asanga Ratnaweera | University Of Peradeniya,Sri Lanka (original) (raw)

Papers by Asanga Ratnaweera

Engineer, May 19, 2021

Bioethanol produced by biomaterials is used in many countries around the world as an alternative ... more Bioethanol produced by biomaterials is used in many countries around the world as an alternative option for gasoline, mainly due to its better emission characteristics. Presently, Sri Lanka depends on imported fossil fuel to fulfil the majority of its transportation fuel requirement and also committed to reduce green house gas emission. Therefore, searching for alternative freely available and low-cost bio resources to produce bioethanol is a timely requirement. This research aims to study the possibility of producing bioethanol from Sri Lankan rotten fruits (without skin) using batch fermentation followed by optimization of the fermentation process parameters. Optimization is carried out by using Response Surface Methodology (RSM) and Genetic Algorithm (GA), and Particle Swarm Optimization (PSO). Bioethanol production is carried out using three different overripe fruits: Banana (Musa ssp.) embul kesel variety, Papaya (Carica-papaya) and Jackfruit (Artocarpus heterophyllus) with two different microorganisms (inoculum) at three different fermentation conditions. The maximum ethanol yield (%) obtained with RMS,

Engineer: Journal of the Institution of Engineers, Sri Lanka, 2021

2007 International Conference on Intelligent and Advanced Systems, 2007

Abstract Handwritten character recognition is playing a vital role in many areas of modern world.... more Abstract Handwritten character recognition is playing a vital role in many areas of modern world. Even though considerable research work has been done in handwritten character recognition, comparatively fewer efforts have been made on handwritten Tamil character recognition. This paper proposes an adaptable method for recognizing handwritten Tamil characters. The adaptability is achieved using a type of artificial neural network called Kohonen self organizing maps (KSOM). In addition, a fine-tuning method, that uses global ...

IOP Conference Series: Materials Science and Engineering, 2018

A new programming interface, ISO14649, named STEP-NC, has been introduced recently to overcome th... more A new programming interface, ISO14649, named STEP-NC, has been introduced recently to overcome the drawbacks of the conventional CNC system. Enhanced machining flexibility, interoperability, and adaptability are the key features of this new programming strategy. STEP-NC technology is based on object-oriented concepts and considers machining processes rather than tool motions as in ISO 6983 for machine tool operation. As such, high level machining features and machining parameters are transferred to the CNC controller, which are eventually used for generating axis movements and other operations. The bidirectional data communication facility of this new strategy enables last minute shop floor level modifications of machining operations at the controller level and establishes a communication pathway to feed major modifications, if required, back to the CAD level as well. Accordingly, the new programming interface allows seamless integration in the CAD/CAM/CNC chain and paves the way for Closed Loop Manufacturing facilities. Most CNC controller vendors have not released STEP-NC compliant controllers yet. Therefore, researchers are developing Open Architecture Control systems to execute STEP-NC and operate CNC machines. This paper reviews research and development of STEP-NC controllers in the last decade and the capabilities of Closed Loop Manufacturing with STEP-NC based systems.

2013 IEEE 8th International Conference on Industrial and Information Systems, 2013

A non linear relationship between an internal combustion engine and its engine parameters such as... more A non linear relationship between an internal combustion engine and its engine parameters such as vibration signals/ exhaust gas is expected to be available. Under various fault conditions, vibration signals were collected using a test-bed to prove this. Fourier transformed vibration signals were mapped to their corresponding faults using a back propagation neural network. The network consists with about 250 input nodes and 150 hidden nodes; resilient back-propagation was used to deal with the complexity created by the high number of nodes. The collected dataset was divided and used for training and testing; and selection combination was changed to check different types of conditions. Using a neural network, creating a relationship between simulated engine faults and their corresponding vibration signals was successful. Although an engine is a complex environment with a lot of unexpected conditions, this result can be used as a start to help predicting engine faults in an efficient and accurate manner. Additional engine characteristics such as exhaust gas/ com port data can also be used to future enhance this fault predicting system.

Abstract—This paper introduces a novel parameter automation strategy for the particle swarm algor... more Abstract—This paper introduces a novel parameter automation strategy for the particle swarm algorithm and two further extensions to improve its performance after a predefined number of generations. Initially, to efficiently control the local search and convergence to the global optimum solution, time-varying acceleration coefficients (TVAC) are introduced in addition to the time-varying inertia weight factor in particle swarm optimization (PSO). From the basis of TVAC, two new strategies are discussed to improve the performance of the PSO. First, the concept of “mutation ” is introduced to the particle swarm optimization along with TVAC (MPSO-TVAC), by adding a small perturbation to a randomly selected modulus of the velocity vector of a random particle by predefined probability. Second, we introduce a novel particle swarm concept “self-organizing hierarchical particle swarm optimizer with TVAC (HPSO-TVAC). ” Under this method, only the “social ” part and the “cognitive ” part of th...

2020 IEEE 5th International Conference on Computing Communication and Automation (ICCCA), 2020

This research presents a real-time visibility enhancement algorithm for effective underwater visu... more This research presents a real-time visibility enhancement algorithm for effective underwater visual navigation. Unlike an aerial environment, an underwater environment is a poor visibility as light travels in the water and the resulting scenes are poorly contrasted and hazy. At present, several vision-based navigation algorithms were introduced by the ground robotic communities. However, most of them fail in underwater due to image degradation. But, there is a possibility to use the same vision navigation methods with image preprocessing which addresses image degradation. Presented paper address the turbidity of the water, the most common problem in underwater image preprocessing, and improved feature point detection and matching which can be used in a vision-based navigation algorithm effectively. The proposed enhancement method combining with, noise removing, artificial light estimation, de-hazing, adaptive depth aware contrast stretching, and image sharpening. The proposed method...

Lack of man power has been identified as one of the major problems for the sustainability of the ... more Lack of man power has been identified as one of the major problems for the sustainability of the Sri Lankan paddy industry. Hence transplanters and seeders were well developed as a step for mechanization. However, weeding method is still not well developed up to mechanization. Therefore, our main objective is to design and fabrication of a power weeder. Weeding ability will be optimized by weeding three rows simultaneously. The machine is designed to use in the fields, cultivated by using mechanized seeder or mechanized transplanter introduced by Farm Machinery Research Centre (FMRC), Sri Lanka. The double-action weeding drums will be driven by a small 1.3 kW gasoline engine, that can enable removal of weeds, while facilitating the forward motion of the machine. In addition, the conical shaped weeding drums will be designed to loose-up soil without harming the paddy. Totally six drums will be used, in such a way that rear three drums have high angular velocity with respect to the fr...

In this study we present attitude stabilization using a vehicle-fixed-frame adaptive controller a... more In this study we present attitude stabilization using a vehicle-fixed-frame adaptive controller and an intrinsic nonlinear PID controller for a low-speed Autonomous Underwater Vehicle (AUV), of complex shape. Controlling an AUV poses a huge challenge because of the non-linearity, time variance and unpredictable external disturbance, as well as because its dynamics and hydrodynamic parameters are difficult to identify due to its geometry. First, a vehicle-fixed-frame adaptive controller is implemented to stabilize the attitudes given. The stability of this desired state-dependent, regressor, matrix-based controller is verified using Lyapunov’s direct approach. Second, an intrinsic nonlinear PID controller is implemented based on the attitude error represented as rotation matrices, to stabilize the attitudes given. This controller requires only an approximate estimate of the inertia tensor of the device. Both the controllers adopt quaternions to indicate the attitude errors to avoid r...

Intelligent and Advanced Systems, …

Handwritten character recognition is playing a vital role in many areas of modern world. Even tho... more Handwritten character recognition is playing a vital role in many areas of modern world. Even though considerable research work has been done in handwritten character recognition, comparatively fewer efforts have been made on handwritten Tamil character recognition. This paper proposes an adaptable method for recognizing handwritten Tamil characters. The adaptability is achieved using a type of artificial neural network called Kohonen self organizing maps (KSOM). In addition, a fine-tuning method, that uses global ...

A STEP-NC or ISO 14649 compliant machine controller is developed, using Open Architecture Control... more A STEP-NC or ISO 14649 compliant machine controller is developed, using Open Architecture Control technology for a three-axis Computer Numerical Control milling machine in this research. The controller is developed on a Raspberry Pi single-board computer, using C++ language. This new development is proposed as a low-cost alternative to ISO6983 standard, ensuring continuous integration in the CAD/CAM/CNC chain in machining; thus, it broadens the spectrum of problems handled by conventional CNC systems. The new machine controller is intelligent enough to extract geometrical and manufacturing parameters, cutting tool data, and material data from the STEP-NC file. Accordingly, tool paths for machining can be generated in the controller itself. The shop floor level modification of parameters and the possibility of regeneration of new toolpaths is an added advantage of this new controller. The modified or improved version of the STEP-NC file can be sent back to the CAD/CAM system to close...

2016 IEEE International Conference on Information and Automation for Sustainability (ICIAfS)

American Journal of Mechanical Engineering

The 2003 Congress on Evolutionary Computation, 2003. CEC '03., 2003

ABSTRACT

SAE Technical Paper Series, 2004