UoM Conferences
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- item: Conference-Abstract1 Watt, quasi-cw, diffraction limited, semiconductor double tapered laser oscillator(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1996-05-31) Dayawansa, IJ
- item: Conference-Full-textA 12v dc/230v ac inverter/charger with advanced Protection features(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1997-11) Ranaweera, A; Seneviratne, BKCC; Kalyanapala, M; Hettiarachchci, PThe inverter can be used as a source of ac power in the absence of grid power. The battery can also be charged by alternative sources of energy if grid power is not available at all. The unit described works as a batter}' charger when the ac mains power is available and automatically starts working as an inverter when the mains power fails. Regulation of the square wave output voltage is achieved by variation of the pulse width of the waveform. A manual switch is also provided to boost the voltage at higher loads. Protection is provided against overloading of the inverter as well as against improper or incomplete connections during charging, thereby protecting the user as well as the unit. The charging current of the battery as well as the voltage level of the battery are indicated on the front panel of the unit. The unit has worked satisfactorily on many types of loads regardless of the high harmonic content of the square wave output voltage.
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- item: Conference-Full-text1st International Conference on Electrical Engineering 2016 (Pre Text)(Institute of Electrical and Electronics Engineers, Inc., 2016-12) Rajapakse, A; Prasad, WD
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- item: Conference-Full-text2nd Annual Conference on Minerals for a Better Future - A Multidisciplinary Approach [Pre Text](Department of Earth Resources Engineering, 2007-11) Karunaratne, S
- item: Conference-Full-textThe 2nd International Conference on Electrical Engineering 2018 (Pre Text)(Institute of Electrical and Electronics Engineers, Inc., 2018) Samarasinghe, R; Abeygunawardana, S
- item: Conference-Full-text2nd International Conference on Information Technology Research 2017 (Pre Text)(Information Technology Research Unit, Faculty of Information Technology, University of Moratuwa, Sri Lanka, 2017-12) Sudantha, BH
- item: Conference-Abstract3+2 versus 5 : A comparison of the structure of architectural education with reference to course changes at University of MoratuwaChandrasekara, DPThe architectural education system at University of Moratuwa (UOM) was changed to a direct 05 year Bachelor of Architecture degree from the 2003 new entrants. Prior to that, the format of the architectural education at UOM was a 03 year B.Sc . (Built Environment) degree and a 02 year M.Sc.(Architecture) postgraduate degree with a minimum of 1 year gaining in between. The structural change of the duration of the course was combined with other major revisions such as the "semesters" and "modules" replacing the "terms" and "subjects" of the old system respectively. The contents of the courses were also changed with the introduction of new areas of studies and elective modules The studio work of architectural design was the forte of both systems. The old system had yearend examinations for theory subjects. The new B.Arch . opted for semester- end examination. The main advantage in the new was that there were lesser possibilities of missing the batch by students due to poor performances in the theory modules. The objectives of this study is to compare the effectiveness of the two systems of education from the perspective of the students. A sample of 30 students; 15 from the last M.Sc. batch and 15 students from the first two batches of B.Arch. students wgfe selected on a random basis. All of them have now completed the part three examination of the Sri Lanka Institute of Architects and are chartered architects. The respondents were divided into two categories "Good students" and "Average Students" based on their performances at UOM. The findings of the study shows that 80% of the "good students" who had followed the B.Arch. programme opt for the same course given a chance to study architecture agaWr 100% of the "average students" select B.Sc. + M.Sc. as their preferred system to study architecture. r " Around 82% of the former B.Arch. students who selected B.Sc + M.Sc path stated that the main reason for the selection is that it gives a postgraduate qualification in addition to the 3 year bachelor degree. Those who selected old system stated that shorter duration and recognition to undergraduate degree as important factors which influenced their decision.
- item: Conference-Abstract3D Environmental force : position impedance variation for different motion parametersRuwanthika, RMM; Harsha, AM; Abeykoon, SThe skill preservation of an expert has been a serious problem for countries with aging population because decrease of the number of successors. The concepts of haptic database and force sensor recorder which have been developed recently suggests solutions of using third multimedia type of haptic communication. Haptic information is a bilateral information of the law of action and reaction. The reaction from real world includes not only position and force information but also environmental impedance. In this paper, the behavior of environmental impedance has been studied with the changes of the different motion parameters like applied force, velocity, position and depth on the object 3D space. This idea is exemplified using a rubber balloon and a rubber sponge which is often modeled using simple linear equations. The experimental results show the importance of considering motion parameters when abstracting haptic information for a haptic database. Nonlinear impedance variations against the motion parameters suggest the necessity of adopting complex haptic abstraction techniques.
- item: Conference-Full-text3D Environmental Force:Position Impedance Variation for Different Motion Parameters(2015-08-03) Ruwanthika, RMM; Harsha, AM; Abeykoon, AMHSThe skill preservation of an expert has been a serious problem for countries with aging population because decrease of the number of successors. The concepts of haptic database and force sensor recorder which have been developed recently suggests solutions of using third multimedia type of haptic communication. Haptic information is a bilateral information of the law of action and reaction. The reaction from real world includes not only position and force information but also environmental impedance. In this paper, the behavior of environmental impedance has been studied with the changes of the different motion parameters like applied force, velocity, position and depth on the object 3D space. This idea is exemplified using a rubber balloon and a rubber sponge which is often modeled using simple linear equations. The experimental results show the importance of considering motion parameters when abstracting haptic information for a haptic database. Nonlinear impedance variations against the motion parameters suggest the necessity of adopting complex haptic abstraction techniques.
- item: Conference-Abstract3D full field deformation measurement using digital image correlation(Department of Civil Engineering, University of Moratuwa, 2021-11) Lowhikan, SS; Mallikarachchi, HMYC; Hettiarachchi, P3D deformation and strain are crucial parameters in engineering design and construction. Precise 3D full-field measurement is useful in identifying the response of the structure under a given loading condition. Digital Image Correlation (DIC) is a non-contact optic-based technique that may prove to be ideal for full-field deformation applications. It has the potential to become an inexpensive, simple, and accurate solution for deformation measurement. All DIC measuring systems now available consist of expensive software packages and experimental facilities which are difficult to access. Therefore, a cost-effective method must be developed to use in the local context efficiently. This research mainly focuses on the development and validation of the cost-effective precise noncontact- based deformation measurement technique. In the proposed method, 3D full-field deformation of the deforming object is measured using two digital cameras and an image processing toolbox available in the MATLAB commercial package. Further, the proposed method efficiency is enhanced by developing it as a standalone application, which can be installed and used by any technician conveniently and utilized for various laboratory Civil Engineering applications. Enhancing the proposed DIC algorithm to improve resolution in 3D applications and extending to phase-changing materials and developing Graphical User Interface (GUI) and general guidelines to be used by a technician were defined as objectives of this research. The proposed measuring system consists of two digital cameras mounted on a rigid frame as it is targeted to capture the specimen and connected to a computer. A random speckle pattern must be applied on the specimen’s surface to track the deformation. The proposed image processing algorithm was developed in MATLAB by using a computer vision toolbox. Later Graphical User Interface was developed using MATLAB App Designer. The developed system was used to obtain the results and validated for rigid body motion tests of concrete cube and cylinder, compression test of concrete, uni-axial tensile test of a dog bone aluminium specimen and shrinkage cracks of mortar experiments. In conclusion, a cost-effective and reliable measurement system was developed by using DIC techniques and MATLAB computer vision toolbox, with its performance validated experimentally by assessment of measurements of the in-plane strain of materials. Even though it has some limitations, the developed algorithm and application can be effectively used for laboratory-scale Civil Engineering related experiments. Also, the application that was developed can be handled by technicians who do not have much knowledge nor understanding of programming languages. The Graphical User Interface that was developed is easy to use and saves considerable time. The performance of the system that has been developed can be assessed and improved for greater precision.
- item: Conference-Full-text3D full-field deformation measurement using stereo vision(IEEE, 2022-07) Sarma, LS; Mallikarachchi, C; Rathnayake, M; Adhikariwatte, V; Hemachandra, KMeasuring 3D deformation and strain are crucial parameters in structural engineering applications both at the construction and operational stages. Precise 3D full-field measurements are useful in structural optimization, damage detection and retrofitting. Digital Image Correlation is a non-contact optic-based measurement technique that is proven to be an ideal candidate in this regard. It has the potential to become a cheap, simple, and precise solution for deformation measurement. However, the currently available Digital Image Correlation measuring systems require expensive dedicated software packages and physical resources which are difficult to access. Therefore, there is a need to develop a cost-effective measuring technique to effectively use it in the local context. This research focuses on the development and validation of a precise non-contact-based deformation measurement technique. In the proposed method, 3D full-field deformation of the deforming object is measured by processing stereo photographs taken with commonly available digital cameras using the image processing toolbox available in the MATLAB commercial package. Further, the proposed method is enhanced by developing it as a standalone application, which can be installed and conveniently used by any technician. Capability of using the developed application in common civil engineering laboratory experiments has been demonstrated.
- item: Conference-Full-text3d full-field deformation measuring technique using digital image correlation(IEEE, 2020-07) Nadarajah, S; Arulkumar, V; Mallikarachchi, C; Weeraddana, C; Edussooriya, CUS; Abeysooriya, RPFull-field deformation measurements are crucial as it offers detailed information to better understand both micro and macroscopic nature of material behavior. The practice of employing Digital Image Correlation (DIC) based measuring techniques in experiments has increased due to its ability to generate full-field deformation information with minimal effort. Even though DIC systems are commercially available, the affordability of those systems is questionable in local context due to high capital costs. Most of the past studies related to DIC were focused on testing concrete, masonry and metallic alloy specimens, and little effort has been made on materials with recoverable large elongations. This paper presents a 3D fullfield deformation measuring system that has been developed with a special focus on hyperelastic materials. The proposed system requires two common digital cameras for image acquisition, as the depth information is of interest. Images are then processed using the MATLAB-based algorithm developed to produce the full-field deformation map. Hyperelastic specimens of two different thicknesses were tested over 70% strain and the accuracy of the strain measurement using the proposed system is validated against physical measurements. The results have shown that the strains can be captured to an accuracy greater than 90% using the proposed technique.
- item: Conference-Full-text3d full-field deformation measuring technique with optics-based measurements(IEEE, 2018-05) Randil, OPC; Mallikarachchi, HMYC; Chathuranga, DFull-field deformation measurements plays a vital role in designing, monitoring and retrofitting many engineering products ranging from civil engineering structure to aerospace applications. Optics-based measurements have gained a vast popularity over last two decades. This paper attempts to establish a method in measuring displacements in a 3D environment, using optics-based measurements, in a cost-effective manner. The study focuses on measuring displacements of a moving object with two stationary cameras. Images acquired from two cameras are processed through MATLAB software package and selected region of the object is reconstructed in a virtual 3D environment at each step. Digital image correlation technique is then adopted to measure displacement by comparing the coordinates of reconstructed objects in each step. It is shown that the displacements can be measured to an accuracy of 0.15 mm (in 20 mm) for the selected object giving an accuracy of 98%.
- item: Conference-AbstractA 3D Geometry-based spatial correlation model for mimo channelsTennakoon, P; Wavegedara2, CBAbstract—This paper proposes a three-dimensional (3D) geometry based spatial correlation model for multiple-input multiple-output (MIMO) communication environments. In the proposed model, it is assumed that scatterers are distributed about the receiver within a spheroid, while the transmitter and receiver antennas are located at the focal points. Approximate closed-form expressions are obtained for the normalized spatial correlation coefficients of frequency non-selective Rician fading channels. As a special case, the normalized spatial functions are derived for Gaussian scatterer distribution. The closedform expressions developed are verified by the simulation results obtained using the WINNER Phase II channel model (WIM2) [17]. Furthermore, the capacity performance of MIMO channels is investigated using the proposed geometry based correlation model.
- item: Conference-Full-text3d modeling and visualization of archaeological sites using modern engineering tools to promote tourism in Sri Lanka(IEEE, 2023-12-09) Kodagoda, G; Wijesinghe, WHMCM; Illangarathna, ANL; Peiris, MDCD; Soysa, HSA; Virudake, PWS; Gunathilaka, HHC; Jayalath, JPME; Jayasinghe, YASS; Isuranda, NW; Jayasooriya, N; Kularathna, AHTS; Abeysooriya, R; Adikariwattage, V; Hemachandra, KThe development of technology has paved the way to apply modern engineering tools in interdisciplinary perspectives. As a country relying heavily on tourism, the ancient heritage of Sri Lanka has its unique features, though it has not been well presented to the world of tourism. Thus, there exists a research gap in reaching out to the world, where the solution lies in collaborating among the fields of Engineering, Archeology and Tourism. The aim of the research is to reduce this gap in visualization of archaeological sites in Sri Lanka integrating modern engineering tools. The methodology involved site visits for physical data collection, drone mappings and 3D scanning. The obtained data is digitized using suitable mapping techniques. The digitized data is used for 3D model creation and visualization which involves steps of platform selection, texturing and rendering with the aid of Virtual Reality and Augmented Reality Techniques. The established framework is applied to two case studies; Thuparamaya Circular Relic House and Jethawanaramaya Image House. With the successful validation of the developed framework for the two case studies, it can be concluded that the developed framework can be used at other ancient archeological sites to promote tourism in Sri Lanka.
- item: Conference-Full-text3R.6R extended water hierarchy model for sustainable use of water during construction(Ceylon Institute of Builders, 2016-07) Waidyasekara, KGAS; De Silva, L; Rameezdeen, R; Sandanayake, YG; Karunasena, GI; Ramachandra, TThere is a broad consensus in literature that effective utilisation of natural resources in any industry greatly influences sustainability of built environment. Hence, better management strategies of water began to emerge in all sectors; thus, different dimensions are in need to assess different industries. With this scenario, water sustainability on construction sites is one significant area, which demands the attention of construction stakeholders. Today many construction projects survive on potable water, and many strategies are available that can reduce the amount of water consumed by the construction industry. Water hierarchy is one strategy proposed for construction sites to reduce potable water consumption and encourage alternative water sources within the site. Literature and preliminary interviews further support identification of new 3R principles: Regulations, Responsibility, and Rewards that can influence on better water management on construction sites. Therefore, purpose of this paper is to examine the applicability and implementation of 3R principles in conjunction with six stages (6R) of water hierarchy to improve efficient water use on construction projects in Sri Lanka. The study adopted triangulation convergence mixed method approach, and data collection involved case studies and a structured survey. Qualitative data is presented as narratives and quotations while quantitative data is presented as descriptive statistics. The results revealed that all factors were considered as ‘applicable’ and the possibility of implementing them on construction sites. Reuse and recycle were identified as the least applicable, and are rarely practised on sites, if it is not initially identified as a mandatory process. Experience and commitment of individual staff and costs are identified as important drivers on implication of each 9R principle. New 3R principles were recognised as supportive policies to implement all six existing stages of water hierarchy. Finally, the paper discusses the extended water hierarchy model developed for construction industry.
- item: Conference-Full-text3R.6R EXTENDEDWATER HIERARCHYMODEL FOR SUSTAINABLE USE OFWATER DURING CONSTRUCTION(2016-08-22) Waidyasekara, KGAS; De Silva, LThere is a broad consensus in literature that effective utilisation of natural resources in any industry greatly influences sustainability of built environment. Hence, better management strategies of water began to emerge in all sectors; thus, different dimensions are in need to assess different industries. With this scenario, water sustainability on construction sites is one significant area, which demands the attention of construction stakeholders. Today many construction projects survive on potable water, and many strategies are available that can reduce the amount of water consumed by the construction industry. Water hierarchy is one strategy proposed for construction sites to reduce potable water consumption and encourage alternative water sources within the site. Literature and preliminary interviews further support identification of new 3R principles: Regulations, Responsibility, and Rewards that can influence on better water management on construction sites. Therefore, purpose of this paper is to examine the applicability and implementation of 3R principles in conjunction with six stages (6R) of water hierarchy to improve efficient water use on construction projects in Sri Lanka. The study adopted triangulation convergence mixed method approach, and data collection involved case studies and a structured survey. Qualitative data is presented as narratives and quotations while quantitative data is presented as descriptive statistics. The results revealed that all factors were considered as ‘applicable’ and the possibility of implementing them on construction sites. Reuse and recycle were identified as the least applicable, and are rarely practised on sites, if it is not initially identified as a mandatory process. Experience and commitment of individual staff and costs are identified as important drivers on implication of each 9R principle. New 3R principles were recognised as supportive policies to implement all six existing stages of water hierarchy. Finally, the paper discusses the extended water hierarchy model developed for construction industry.