Browsing by Author "Wickramarachchi, N"

Now showing 1 - 20 of 28

item: Article-Abstract
An Intelligent Supervisory Control System For A Fish Processing Workcell
De Silva, CW; Wickramarachchi, N
A laboratory workcell has been developed for fish cutting. The workcell, which uses a variety of sensors, actuators, and hardware for component interface and control, operates with the help of a dedicated supervisory control system. A layered architecture has been used for the system. It has several knowledge-based modules for carrying out tasks such as workcell monitoring, controller tuning, workcell conditioning, and product quality assessment. The paper describes the workcell and the intelligent supervisory control system. Performance of the supervisory system is studied through fish cutting experiments
item: Article-Abstract
An Investigation of the Effects of Fuzzy Resolution on Control Inference Using Explicit Relationships
Wickramarachchi, N; De Silva, CW
The number of partitions or fuzzy states that exist in a fuzzy variable determines the resolution of that variable. This paper investigates the effect of fuzzy resolution on the control action that is derived from a fuzzy-control rulebase. First, it is shown that some explicit relationships could be derived for the inference from a fuzzy rulebase in terms of input variables and known geometry of the membership functions. These relationships are established for a generic, single-input-single-output (SISO) fuzzy control rulebase that employs uniform triangular membership functions. Specifically, a formula for control action u is derived in terms of incremental input variable and corresponding membership grades and fuzzy resolution. The result is then extended to include global variations of the input variable. It is argued that the resulting equations could be used to demonstrate the applicability of fuzzy control rules in a wide variety of control situations. Also some useful properties that arise from these equations are identified
item: Article-Abstract
An optimized anti-lock braking system in the presence of multiple road surface types
Rattasiri, W; Wickramarachchi, N; Halgamuge, SK
In this paper, the use of adaptive anti-lock braking system (A-ABS) comprising of a road surface identification (RSID) system and road surface information modules is presented. The proposed ABS system is capable of identifying and differentiating different types of road surfaces, and applying an amount of brake force appropriate to the road surface type being encountered in order to prevent wheel lockup as well as to minimize the braking distance. A discriminative hierarchical evolutionary fuzzy system learns and identifies on-the-fly the road surface characteristics, from a set of built-in road surface information modules, in a closed-loop adaptive configuration. The closed-loop nature of RSID allows the system to adapt and respond very fast to a sudden change in surface condition. In order to verify the performance of the proposal, simulation results obtained from cars equipped with A-ABS, a reference ABS, and a non-ABS are provided and discussed.
item: Conference-Abstract
Appliance-level demand identification through signature analysis
Dhananjaya, WAK; Rathnayake, RMMR; Samarathunga, SCJ; Senanayake, CI; Wickramarachchi, N; demand identification; harmonic analysis; signature analysis.
Appliance specific load monitoring is very useful in energy management solutions that are becoming a challenging task with growing energy demand. It facilitates appliance recognition and load monitoring such that optimum resource utilization can be achieved by correct appliance scheduling. In this paper we present a study of non-intrusive load recognition using steady state appliance signatures for identifying commonly used household appliances. Current harmonics, active and reactive power components acquired from data loggers are used as appliance signature in this study. This analysis enables the capability of providing detailed information on appliances in use and consumers could benefit from customized energy management recommendations. Also, suppliers could implement smart metering technology introducing appliance level information as well. We propose algorithms for non-intrusive load recognition using combination of several methods and techniques. It was seen that a higher accuracy of identification could be achieved when a combination of techniques are used rather than using a single technique.
item: Conference-Full-text
Appliance-Level Demand Identification Through Signature Analysis
(2015-08-03) Dhananjaya, WAK; Rathnayake, RMMR; Samarathunga, SCJ; Senanayake, CI; Wickramarachchi, N
Appliance specific load monitoring is very useful in energy management solutions that are becoming a challenging task with growing energy demand. It facilitates appliance recognition and load monitoring such that optimum resource utilization can be achieved by correct appliance scheduling. In this paper we present a study of non-intrusive load recognition using steady state appliance signatures for identifying commonly used household appliances. Current harmonics, active and reactive power components acquired from data loggers are used as appliance signature in this study. This analysis enables the capability of providing detailed information on appliances in use and consumers could benefit from customized energy management recommendations. Also, suppliers could implement smart metering technology introducing appliance level information as well. We propose algorithms for non-intrusive load recognition using combination of several methods and techniques. It was seen that a higher accuracy of identification could be achieved when a combination of techniques are used rather than using a single technique.
item: Thesis-Abstract
Automated control approach for industrial welding transformer to minimize the idling power loss
Jeeth, ADM; Wickramarachchi, N
Main objective is to design and implement automated control circuit to switch ON & OFF main power feeding contactor of industrial welding transformer, depend on the work pattern. Voltage sensing at the out put terminals of secondary winding of welding transformer is used as a one and only input signal for the control circuit. Reduced voltage 24 VAC is supplied to primary during idling and during operation it converts in to 400 VAC, and this conversion takes place automatically. By that, able to reduce idling power loss on primary winding due to open circuit core loss & iron loss. During designing of new system special attention was made, not to change existing conventional welding procedure and not to introduce additional external sensors and cables other than conventional welding electrode and welding cable. New system was practically implemented in yard and tested for long period of time in different work conditions in Colombo Dockyard PLC. System was tested with existing conventional welders but no behavioral changes were observed during welding operation after implementing new system. Successful trails were carried out and proved it uninterrupt operation. Under guidance and instructions of my project supervisor I worked and finally able to came up with practically feasible solution. This report describes problem identification, how the design concept developed, power saving and cost benefits .to yard after implementation of new system. The report starts with an introduction as a 1st chapter where describe the current welding practice at Colombo Dockyard PLC, how to reduce idling power loss by implementing new method and final goal of my project. 2nd chapter describes the statement of the problem and problem identification, new solution and how it affects to save energy. The 3rd chapter consists with gathered technical data and its analysis during execution of design approach. Next 4th chapter describe about proposed and implemented solutions for the identified problem and evolution of design concept. Fifth chapter describes the energy saving calculations and cost benefit analysis. Finally, in the conclusion, I have explained practically and economically viability of new product as a industrial product.
item: Article-Abstract
Biological Sequence Data Preprocessing for Classification: A Case Study in Splice Site Identification
Baten, AKMA; Halgamuge, SK; Chang, B; Wickramarachchi, N
The increasing growth of biological sequence data demands better and efficient analysis methods. Effective detection of various regulatory signals in these sequences requires the knowledge of characteristics, dependencies, and relationship of nucleotides in the surrounding region of the regulatory signals. A higher order Markov model is generally regarded as a useful technique for modeling higher order dependencies of the nucleotides. However, its implementation requires estimating a large number of computationally expensive parameters. In this paper, we propose a hybrid method consisting of a first order Markov model for sequence data preprocessing and a multilayer perceptron neural network for classification. The Markov model captures the compositional features and dependencies of nucleotides in terms of probabilistic parameters which are used as inputs to the classifier. The classifier combines the Markov probabilities nonlinearly for signal detection. When applied to the splice site detection problem using three widely used data sets, it is observed that the proposed hybrid method is able to model higher order dependencies with better classification accuracies.
item: Conference-Extended-Abstract
Business process re-engineering with IT as a tool
(2002) Madanayake, OC; Jayawardane, AKW; Wickramarachchi, N
This paper explains the application of Business Process Re-engineering (BPR) combined with IT as a tool to re-engineer the process of issuing transcripts to the graduates of the University of Moratuwa. The deep-set investigation and the redesign of tasks in this process brought to light many interrelated processes in the university. The authors were able to arrive at a Student Adrninistration System, which facilitates student registration, transfers, examination information and other ad-hoc information requirements.
item: Conference-Extended-Abstract
Control of electrical appliances from hand tracking
(2009) Wickramarachchi, N; Bandara, HMSLG; Jayarathna, KHEH; Karunapala, PMAU; Senevirathne, MRKC
Control of Electrical appliances from hand tracking is our final year project and mainly based on newly emerging image processing technology. Image grabbed by the camera will be processed by PC and if it is identified any new gesture it will given to the microcontroller. Microcontroller will generate the correct control signal for that gesture and it will be transmitted to the receiver through transmitter. Receiver unit will identify the control signal correctly and it will provide the relevant output for the control circuit of the appliance.
item: Article-Full-text
Craft industries and ribbon development: place change along the Colombo-Kandy road, Sri Lanka
(Faculty of Graduate Studies, 2022-12) Ranathunga, G; Wickramarachchi, N; Grodach, C; Karunarathne, V; Ratnayake, R
The research project started in 2019 and by 2020 had completed the in- depth observation and collected the participatory observation data resources too. According to researchers from Moratuwa University, due to the country being locked down for two years periodically due to an unexpected COVID 19 pandemic, the huge economic backwardness that may occur in the country in the future is foreshadowed. As university researchers, conducting research predicting the future is an urgent need. The analysis of this research data revealed that traditional craft industries are a city system that has emerged over time based on geo- political, economic, social and cultural traditions of the country. The researchers explain that it is a local imperative to develop this craft village concept into a broader concept, the creative city concept, through government intervention. It will be a victory for us as researchers if we are able to convince the existing government to start a permanent program to nurture the local economy by combining the creative city concept, a greater concept, with the local tourism industry of the country. It is important to identify the existing craft-associated business model to implement the creative craft city concept. According to UNCTAD 2018, the craft industry is becoming more and more crucial for economic growth in Asian nations, both as a direct export and for destination -specific tourism (Cohen 1995; Gough and Rigg 2012; He and Gabhardt 2013; Saha and Sen 2016).Although the structure and purpose of commercial creative industries in Western cities have been extensively studied (Scott 2010, for example), this information cannot be directly applied to traditional craft industries, especially in other parts 40 of the world where histories, urbanization patterns, and agglomeration dynamics are distinct (Phelps and Wijaya 2020).Craft industries are prevalent in peri-urban cities, villages, and desakota in South and East Asian nations where the lines between urban and rural life converge (McGee 1991; Rigg 1998). They develop in a distinctive morphological pattern known as “craft ribbon development,” which runs along major thoroughfares or roadways (Cohen 1995).
item: Conference-Extended-Abstract
Critical factors for the adoption of groupware technologies in organizations in Sri Lanka
(2003) Madanayake, OC; Jayawardane, AKW; Wickramarachchi, N
Since the age of the industrial revolution, many technologies have surfaced, yet none could compare to the reception that computers received. It is by far the most popular technology to knock on the doors of the modern world. Homo sapiens being the race they were, were 110tsatisfied with the power of a mere computer. Networks were invented which paved the path to the Internet. The Internet proved to be a record breaker. never before has such a mass of people adapted in such a short space to a new Technology. Internet harbors many technologies under its wings and the list includes Groupware.
item: Conference-Extended-Abstract
Design and implementation of high-power- factor dimmable fluorescent lamp ballast circuit
(2010) Ratnayake, KMUS; Priyankara, WDS; Premachandra, WAD; Rajapakshe, RPRH; Wickramarachchi, N
Lighting is an essential element of home and work environment that affects lives of people in many different ways. In Sri Lanka, people spend significant amount of their electric hills on lighting. As one of the widely used lighting solutions hath in industrial and household applications, improving the quality and reliability of fluorescent lamps are certainly of great importance Enabling of dimming with the improvement of the power factor not only makes the fluorescein lamps more economical and reliable, it also adds the benefit of more user satisfaction over existing designs The proposed implementation of the design is commercially viable since it has man) commercial benefits over similar products available in the marker Although die initial installation costs of the product is quite high compared to conventional ballast, the payback time is considerably less especially when die product is used with multiple lamps at the same time
item: Article-Abstract
Design of a Fuzzy Logic Controller to Enhance Power System Small Signal Stability
Wickramarachchi, N; Gunathilake, DKPU
A reliable and continuous supply of electric energy is essential for efficient functioning of the modern sophisticated society. Due to a combination of burgeoning energy consumption and impediments to increasing generation and transmission capacity, utilities are forced to operate the power systems ever closer to system stability limits. This in turn necessitates use of special control aids to improve damping of low frequency electromechanical oscillations. This paper presents development of a fuzzy logic based power system stabilizer to maintain stability and enhance closed-loop performance of a power system under disturbances. The proposed fuzzy controller is trained with an optimal controller designed by the current researchers. The effectiveness of the proposed fuzzy controller in a single machine infinite bus power system is demonstrated under a wide range of system and test conditions. Its performance is compared with that of a conventional lead-lag power system stabilizer and the designed optimal controller. Computer simulation studies show that the proposed fuzzy controller outperforms and improves the system damping compared to the conventional and optimal controllers.
item: Thesis-Abstract
The design of a sustainable efficient lighting program for Sri Lanka
(2014-08-01) Perera, MGMSU; Wickramarachchi, N
In each year, electricity distribution expands through various requirements such as state sponsored rural electrification schemes and other interventions, connecting more consumers to the national grid, means the demand growth at the end of each year. The main challenge facing the CEB will be the rising price of oil and the generation capacity shortage. Generation capacity additions are required every year to keep pace with the increasing demand. Unless cheaper solutions are developed to meet this electricity demand, the financial burden of fuel oil based power generation will further strangle the government owned CEB. Importance of demand side management strategies have rapidly grown in the context of rising oil prices as well as extensive delays in implementing low cost electricity generation projects. Especially as a developing country, saving of energy has much more advantages. This report proposes to maximize the usage of existing capacity by introducing a sustainable lighting programme to popularize the use of efficient lighting devices among the consumers as energy development, which will offset the adverse impacts. The most economically effective method to achieve this goal is to introduce compact fluorescent lights among the consumers. That is because while a regular (incandescent) light bulb uses heat to produce light, a fluorescent bulb creates light using an entirely different method that is far more energy-efficient - in fact, 4-6 times more efficient. It can be easily implemented if a CFL bulb is priced as per the incandescent bulb price and distributed through CEB depot / offices.
item: Thesis-Full-text
Design of dual axis force sensor for aerospace application
Prasanna, IKH; Wickramarachchi, N
This work reports on the design procedure of a dual axis force sensor for aerospace applications. System functionality of the force sensor should comply with many reliability aspects peculiar to aerospace industry rather than just sensing the applied force. Final design of the dual axis force sensor is based on three preliminary design concepts and test data of fabricated models. This report discusses descriptively how to come up with new ideas through these models. Mathematical model of the sensor is used to verify design outcomes. Furthermore this work presents the practical circumstances faced during fabricating and testing. Analysis of results are also discussed in the report and comparison of the first three models included in the report. Functional requirements were fine tuned in the final design compared to the first three design concepts. Major requirement was to reduce the cross sensitivity when it came to the final design. As desired cross sensitivity was 2% of the applied load, Final design enabled to achieve 2.21% pitch cross sensitivity and 3.84% roll cross sensitivity. It was considerable reduction of the cross sensitivity. Non linearity value was reduced by 65.79% and 38.46% pitch and roll respectively. Achieved non linearity value was 0.065% and 0.08% in pitch and roll direction respectively. Hysteresis also reduced by 73.91% in pitch direction and 21.43% in roll direction. Output of the Wheatstone bridge has to be reduced in order to decrease the cross sensitivity. This required more amplification, causing the reading and the noises to be amplified at the same time. It was required to have more signal conditioning that was a drawback of the system developed
item: Thesis-Full-text
Design of green tire painting machine
Bandara, SA; Wickramarachchi, N
The tire manufacturing process IS a long process that includes lots of hazard operations. Manual green tire painting method is also considered in to this category. Green tire is the tire which builds according to the tire construction and which is ready for the curing process. Before the curing process, it has to apply lubricant inside the green tire and flow property improving agent on the out side. This application is called green tire painting. The main objective of this project is to design a new machine for green tire painting and protect operators from harsh environment, and improve the productivity. This project is focused more on actual requirements and takes a practical approach. When selecting components, it is restricted to select popular brands, which is recommended by the company. All the selected components are available in the market with reasonable price. As this is an actual machine design, I focused more on durability, productivity, safety and budget. The green tire painting machine is automated by the control unit which is a commercially available programmable logic controller (PLC). The requirement of the sensor units for the PLC and the control program is also implemented as part of this design.
item: Thesis-Full-text
Development of a high speed stapler pin manufacturing machine
Palagama, SP; Jayasekara, AGBP; Wickramarachchi, N
Converting any kind of production system from discrete process to continuous process saves substantial time in production process enabling reduction of power consumption, reduction of space, utilized to increasing production capacity. That can be applied for development of existing manufacturing processes; here used for steel wire production processes.Stapler pin was invented in late 1877’sfor binding of materials, popular due to simple form of use in the industry and now it has become an essential commodity in the market. In past decades, stapler pin manufacturing process have not been developed and used conventional manufacturing process all over the world which have limitations due to high energy consumption and high space requirement; therefore setting up such factories leads to high capital investments.The objective of this study is to Development of High Speed Stapler Pin Manufacturing Machine to introduce to the local market and cope up the target. Total requirement of the stapler pins of different sizes for office uses and industrial uses are imported and distribute by various suppliers in Sri Lanka. No one can think of manufacturing stapler pins in Sri Lanka due to high capital investment and high operation cost and lack of own technology. Now many suppliers import base product and packet locally and distribute through super markets and retail markets. Stapler pin manufacturing process involves very simple mechanical functions of wire forming, feeding, cutting, bending, moving and gluing. Conventional stapler pin manufacturing is done by using round galvanized steel wire of different wire gauge from 18 to 26 based on the application.Single or multiple wire which feed through set of rollers to straitening and forming it’s flat shape then gluing it by using gum. Then heated to dry and make wire flat strip. After it cut and bent to correct size to produce stapler pin by using mechanical actuator by aid of square shaped die and mold which moves up and down.In this design mechanisms have completely changed to make its square shape by using rotary bending mechanism. Steel wire feed through freely rotating rollers by using rotational square bar then it cut by using rotating cutting tool while moving stapler pin forward. Cutting tool moving up and down enabling to produce two stapler pins at a time. In this Design of high speed stapler pin manufacturing machine addresses to save energy, time and space leads to convert factory manufacturing environment to domestic manufacturing environment. Use of time, space and energy saving strategy is most economical and applicable in modern industry accordingly manufacture of stapler pins can promote / emerge into the domestic industry and this product enabling to country economic development.Two types of conceptual machines have been developed and relevant prototype models have been tested. Only one type of the conceptual design has been successful. Further improvements and developments have been incorporated to the successful model in order to produce stapler pins with correct shape and dimensions. Power requirements have been calculated by using theoretical approach by using formula and also experimental power requirement has also been calculated by experimental approach and observed that both power requirements are almost the same. Therefore the formulated equations can be used for further developments in the proposed process. Machine will be used in domestic manufacturing environment; hence certain safety precautions were concerned when selecting the power source, drive motor, heater and control system.
item: Thesis-Abstract
Development of an image recognition systems for crop disease indentification of paddy field in Sri Lanka
Anthonys, G; Wickramarachchi, N
The classification and recognition of paddy diseases are of the major technical and economical importance in the agricultural industry. To automate these activities, like texture, color and shape, disease recognition system is feasible. The goal of this research is to develop an image recognition system that can recognize paddy diseases. Images were acquired under laboratory condition using digital camera. Four major diseases commonly found in Sri Lanka, Rice blast (Magnaporthe grisea), Rice sheath blight (Rhizoctonia solani), Brown spot (Cochiobolus miyabeanus) and False smut (Ustilaginoidia virens) were selected for this study. Image processing starts with the digitized a color image of paddy disease leaf. Then a method of mathematics morphology was introduced to segment these images. Then texture, shape and color features of color image of disease spot on leaf were extracted, and a classification method of membership function was used to discriminate between the four types of diseases. The analysis of the results shows over 70 percent classification accuracy over 50 .sample images. The conclusion is that in case of reasonably good images, this approach yields excellent results, Use of powerful RGB camera would allow higher precision of the image color and segmentation
item: Thesis-Full-text
Development of communication network for automatic meter reading system
(2015-09-16) Weerasinghe, AA; Wickramarachchi, N; De Silva, N
This thesis presents a research work which is carried out to find out correct network resources requirement for an automatic meter reading system. There are various technologies available to automate the meter reading such as PLC, messaging over GSM, telephone line and RF technologies. As far as utilities providers are concerned, their focus is on a reliable AMR system to read the meter at minimum cost. Development of a reliable AMR system is highly dependant on telecommunication infrastructure which is costly. Therefore, network resource planning needs to be researched in depth to develop a reliable utility wide AMR system. This particular research is on data concentrator based AMR system focusing on the analysing of cross relationship between channel requirements of the last mile data communication channel, data concentrator memory requirement and backbone channel bandwidth requirements. This research has established mathematical simulation models for the last mile channel communication, data concentration memory and backbone channel communication infrastructure and integrated into a single model using software tool MATLAB Simulink. This model has established a scientific conclusion of a methodology to estimate the infrastructure requirements to design of such data concentrator based AMR system. Developed MATLAB Simulink program is used as a computational algorithm that can repeat the program with multi variable inputs to obtain the numerical results. Monte Carlo method is quite useful for solving this kind of simulating phenomena with having many degrees of freedom, significant uncertainty in inputs and wide variety of scenarios. Various sampling parameters were input to the system and, related results for various scenarios were obtained. These results were then used to find out cross relationships between three main components of a data concentrator based AMR systems and their requirements. The results of this research are also adopted to develop a utility wide AMR system as pilot projects with LECO staff at various distribution networks.
item: Thesis-Full-text
Develpment of a multi agent system for voltage and outage monitoring
(2015-10-29) Bodhinayake, G.G; Wickramarachchi, N; De Silva, N; Hemapala, K.T.M.U
This thesis presents a research work which is carried out to implement a multi agent system for voltage and outage monitoring system for Sri Lankan electricity distribution network. In Sri Lankan distribution network most of the new technological features can be seen in the different part such as automated meter reading, remote breaker operations. But distribution system fault identifications, voltage monitoring and network reconfiguration are carried out using basic technologies. Automated Meter Reading (AMR) system is introduced to read analogue energy meters remotely. Research on agent based AMR system is established with four major projects. Those are Agent based meter reading system, network resource planning of the agent based system, agent network reconfiguration and restoration project and Agent based voltage and outage monitoring system This particular research is on a development of Agent based voltage and outage monitoring system formulated for power distribution network using Multi Agent System. Establishment of agent based monitoring system is developed with the defined model in a part of the area network. The model is established to represent the distribution network and to collect voltage and interruption data to the server. Five major agents namely, Database Agent, Meter Agent, Breaker Agent, Area network Agent and Reporting Agent are defined. Voltage data collected from GPRS meter reading technique in Maharagama area is selected for the case study. Six different data sets are considered under the case study. There are four different types of voltage failures are identified as High voltage, low voltage, Branch failures and individual meter faults. These four scenarios are compared with conventional method and agent based system. Agent based monitoring system is continuously updated through GUI and it would visualise the voltage level of the network. It would enhance the functions of the control room operator. Transformer setting changes can be changed while monitoring high voltage and low voltage areas. Distribution network augmentation can be done with monitoring system by increasing transformer capacity or introducing new transformer in identified areas. Different types of GUIs are established to maintain easy monitoring system and reporting system. The reporting system is included the agent based report generation for power quality measurement indexes. Individual index vales of each consumers and the whole area network index can be monitored through this system. Scalability and the flexibility of the monitoring system increased with defined Multi Agents.