Faculty of Engineering
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Publication Open Access A Framework for Network Level Pavement Maintenance Planning for Low Volume Roads(Spriger Link, 2020) Pasindu, H. R; Sandamal, R. M. K; Perera, M. Y. ILow volume roads (LVRs) play a pivotal role in the economic development of rural areas especially by providing connectivity for the communities to access markets, education and social needs in an efficient manner. They serve as the link between the local road network to the arterial and collector road network designed at providing accessibility to residential, agricultural or industrial areas. Lack of funding, subjective and ad hoc decision making has resulted in an inefficent utilization of resources in the local road agencies. Lack of a sound analytical process is a major impediment to maintain these roads in cost effective manner under the resource constraints prevalent. Existing pavement management systems (PMS) require extensive data collection and complex analysis processes, which makes them impractical to be deployed in local agencies. The core attributes of the proposed system are, reduced the data requirements, simplified the analytical tools and allowing users to customize considering the resource constraints. In this study, a relationship between International Roughness Index (IRI) and relevant distresses for LVR is established and based on that cost estimation model is developed for distress repair. Furthermore, the strategy which provide maximum condition for preventive maintenance is found by using decision tree approach in the network level optimization. A case study illustrated that the use of proposed PMS provides better overall network condition with compare to conventional decision making for same budget level.Publication Embargo Optimization of controller gains for FPGA-based multivariable motion controller using response surface methodology(IEEE, 2015-05-03) Sekaran, H. P; Liyanage, M. H; Krouglicof, NField Programmable Gate Arrays (FPGA) have become increasingly popular in recent years for control applications. Using contemporary FPGA technology, a powerful virtual processor can be synthesized and integrated with custom hardware to create a dedicated controller that outperforms conventional microcontroller and microprocessor based designs. The FPGA based controller takes advantage of both hardware features and virtual processor technology. This study details the development of a cascaded type PD controller for an inverted pendulum system implemented on a single FPGA device. The controller includes a hardware based implementation of the IO modules including quadrature decoders/counters and a Pulse Width Modulation (PWM) controller for the motor driver. The NIOS II processor was synthesized to implement the cascaded PID controller algorithm. This study also proposes a novel method for obtaining the optimal controller gains for the system. It uses the Central Composite Design (CCD) in Response Surface Methodology (RSM) for obtaining these gains. A classic inverted pendulum system was selected to demonstrate the applicability of the proposed approach. The gains provided by the RSM were verified experimentally to validate the proposed controller tuning method.Publication Embargo Optimization of cluster head rotation in energy constrained wireless sensor networks(IEEE, 2007-07-02) Gamwarige, S; Kulasekere, E. CThe performance of energy driven cluster head (CH) rotation algorithms have been shown to be far more superior to time driven CH rotation algorithms when it comes to maximizing the sensor bed lifetime. The sensor bed life time is improved by selecting the proper points at which a CH role is relinquished to higher energy nodes via a CH rotation phase. However no formal analytical method is available to find the optimal point at which the CH rotation should be carried out. This research proposes an analytical iterative method to obtain the optimal points at which the CH rotation can be carried out. The method proposes an optimal value c opt for the energy threshold at which this rotation could occur. The values obtained via the analytical method is shown to be optimal via simulations using the EDCR and EDCR-MH algorithms. The analytical method proposed can be used in any energy driven algorithm to find the optimal point for CH rotations avoiding any ad hoc simulation based methods to maximize the lifetime of the sensor bed.Publication Open Access Optimization Methodologies for Building Performance Modelling and Optimization(FACULTY OF ENGINEERING, UNIVERSITY OF MORATUWA, 2013) Bandara, R. M. P. S; Attalage, R. ABuildings account for approximately 40% of the global energy consumption and 36% of total carbon dioxide emissions. At present, high emphasis is given on the reduction of energy consumption and carbon footprint by optimizing the performance and resource utilization of buildings to achieve sustainable development. Building performance is analyzed in terms of energy performance, indoor environment for human comfort & health, environmental degradation and economic aspects. As for the energy performance analysis, this can be best modeled and optimized by a whole building energy simulation tool coupled with an appropriate optimization algorithm. Building performance optimization problems are inherently multivariate and multi-criteria. Optimization methodologies with different characteristics that are broadly classified as Adaptive, Non-adaptive and Pareto Algorithms can be applied in this regard. The paper discusses the applicability of the aforementioned optimization methodologies in building performance optimization for achieving realistic results.Publication Embargo Optimum sizing and tracking of combined cooling heating and power systems for bulk energy consumers(Elsevier, 2014-04-01) Jayasekara, S; Halgamuge, Saman K; Attalage, R. A; Rajarathne, RThe optimization of combined cooling heating and power (CCHP) systems involves two major tasks: searching for optimum design parameters and for optimum regular operation variables. This paper proposes a two-stage method to solve both tasks. The operation of large thermal power plants must be altered smoothly, as quick changes in system settings may result in cascade tripping of subsystems, ultimately leading to a complete shutdown. This work uses graphical representation of the operational space of the system, which helps in tracking the operation along its optimum trajectory smoothly. The daily energy demands of a five star hotel, collected over a year, were used to demonstrate the applicability of the proposed method. Using the proposed method reduced the total annual cost over 7% and 13% in Australia and Sri Lanka respectively, compared to the conventional method of following thermal load.