Browsing by Author "Wickramarachchi, NK"

Now showing 1 - 5 of 5

item: Thesis-Abstract
Automation of traffic flow measurement using video images
De Silva, GC; Wickramarachchi, NK
This research focuses on the design and implementation of a system for automating the task of measuring vehicular traffic flow on a motorway, using video image sequences. Such a system is useful when designing traffic management systems such as signal lights at road junctions. It can also function as part of an intelligent transportation system, providing useful quantitative information, such as number and size of vehicles, speed and direction of movement etc, for managing vehicular traffic effectively. The system processes a sequence of images captured by a video camera mounted above a motorway. It performs motion segmentation on the images using background subtraction, and derives traffic parameters using a combination of image processing techniques such as statistical methods and solving systems of equations. While making use of existing algorithms for image processing and image sequence analysis, new algorithms have been developed and employed for background extraction and occlusion modeling. The system has been designed to handle inconsistencies caused by occlusion of vehicles, by predicting the motion of vehicles using the derived parameters of motion. Knowledge about the traffic scene has been used by the system to improve the accuracy of results. The system relies on a centralized 'knowledge base', a source of information related to the traffic scene. This knowledge base is loosely coupled to the system in such a way that the system can be customized to perform well in different traffic scenes by changing only the content of the knowledge base. The system has been implemented to work on an IBM PC based system with an Intel Celeron 450 MHz processor and 64MB Memory. The tools for implementation have been selected after a study of their performance. This automated traffic flow measurement system has been tested using three image sequences from different traffic scenes. A number of tests have been conducted by varying the frame rate, image resolution and the method used to create the background image. The results have been compared with each other, as well as the ground truth, while recording the processing time involved with each test case. The automated system measures traffic parameters with an average accuracy of 90%. The new technique that has been proposed in this work for background construction produces the most accurate result. Processing speed can be improved by reducing the frame rate and the resolution of images, with a slight reduction in accuracy of the results.
item: Conference-Full-text
Design and construction of an automated test bench for mcb testing
(IEEE, 2016-05) Wickramarachchi, NK; Amaradasa, WGM; Amarasinghe, HKJ; Karunarathna, HKTR; Wijekoon, WM; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Testing of MCBs involve sending a preset current through the MCB under test until it trips or if not for a predefined period of time. The operational state of the MCB should be recorded for variable currents. Automation of the testing process for household MCBs is presented in this paper. This paper includes design of the testing process and simulation of the controllable current source. Maximum current which can be injected by the current source is 390 A for a short time duration.
item: Thesis-Full-text
Implementation of integrated systems monitoring tool for power and network applications in expressways
Jayasuriya, NRE; Chandima, DP; Wickramarachchi, NK
With the rapid development of information and communication technology, use of electronic and telecommunication based systems is increasing day by day. It improves the efficiency and quality of most of the traditional work flows by replacing fully manual operation procedures with fully automated systems or with partially automated operation with significantly reduced number of staff. Operation of all modern expressways uses such systems significantly in large geographically distributed area for efficient management of expressways with enhanced comfortability and safety. But it will add an additional workload on expressway maintenance team to manage all critical systems in operation with minimum or theoretically with zero downtime. System monitoring is one of the key elements in systems operation to verify its operation. It helps system maintenance team to identify the status of the system remotely. But, the system monitoring has not been implemented completely in Sri Lankan expressways, causing difficulties to identify system problems as soon as they occur. It was understood that this factor has major impact on the reliability of the systems operation by studying past operation experience. Hence the objective of the proposed design is to improve availability and reliability by minimizing down times of IT and Electronic systems in the expressway. During the first part of this research, operation of two similar scenarios was selected for background study. Initial study is from Japan, which is a country of having more than fifty year experience of operation of the expressways and related facilities. Second study is performed with Sri Lanka Telecom, the pioneer of the telecommunication industry in Sri Lanka. Reliability analysis was performed based on the log book entries of the systems maintenance team of Southern and Outer Circular expressways in Sri Lanka, to identify possible scenarios of faults occurred and how its effect on the reliability of critical systems and challenges faced on identification of faults during corrective maintenance sessions. As the second part, theoretical design of an integrated systems monitoring application was carried out by following modular design approach. The design is covered all critical functional blocks of a monitoring system with a model for performance analysis. The new design consists of several improvements over conventional monitoring systems to enhance the functionality. Several methods were designed for alarm optimization to reduce number of repetitive alarms. Heuristic knowledge base was linked with the designed monitoring system, hence it ensures that the maintenance personal is updated with its all history records before attending to the repair. Implementation of designed monitoring system was completed in all critical components. It included both software and hardware module implementation and deployment. All modules use open protocols and open source software components. Several functional tests were carried out with their performance values both in a test bed and in the production environment. The results indicated that the system is working as expected and help to improve the availability of systems through proposed methodologies.
item: Thesis-Abstract
Improving damping in power system oscillations using fuzzy logic stabilizer
Chandrasena, RPS; Lucas, JR; Wickramarachchi, NK; Peiris, HJC
In general, power system oscillations are damped out using power system stabilizer (PSS). Conventional power system stabilizers are based on linear control theory. Therefore, they provide optimal operation at the nominal operating point around which the system is linearised during their designing process.// Power systems are in general non-linear and their operating point can vary over a wide range. Power System parameters also change with time because its configuration changes with time continuously. Therefore, a conventional power system stabilizer cannot provide better performance over the whole operating range since it cannot support the deviation of its parameters. Hence, a controlling method, which can tolerate the small deviation in system parameters, is highly welcome.// Fuzzy Logic provides a simple way to arrive at a definite conclusion based upon vague, ambiguous, imprecise, noisy or missing input information. So, a controller based on Fuzzy Logic (Fuzzy Logic Controller) is one of the most promising solutions to the above problem. Since, it can tolerate the changes in the system parameters, it may provide a better performance over a wide operating range. Hence, in this research project, a power system stabilizer based on Fuzzy Logic (FLPSS) has been designed and various tests have been conducted on it in order to check its effectiveness. The performance of the designed FLPSS has been compared with the performance of a particular conventional power system stabilizer and the FLPSS has shown better performance at each occasions.
item: Thesis-Full-text
Technoeconomic analysis of led lighting as a solution for outdoor stadium lighting in Sri Lanka
Perera, PM; Wickramarachchi, NK
This study explores the possibility of adopting LED lighting for professional sports lighting projects over the conventional technology. LED lighting has the advantage of lower power consumption and longer lifetime, however being a new technology LED luminaires are very expensive than conventional luminaires. Therefore in some cases it is debatable whether LED lighting is a feasible solution. Sports lighting is an area in lighting where there are very particular requirement in illumination level, uniformity, glare and colour rendering. Therefore LED luminaires specialized for sports lighting are very limited in the market. In this study, LED and conventional lighting designs are done for various sports applications and the two systems are compared. Economic analysis is done in terms of simple payback and IRR to check whether LED lighting is feasible for sports lighting in current scenario. Also various factors affecting to the feasibility of LED lighting for sports lighting is identified and sensitivity analysis is done to identify under which conditions LED lighting become advantageous over conventional lighting technology for sports lighting. In addition qualitative analysis is also done of sports luminaires of both LED and metal halide technology.