ICACT 2018
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Item An Initial Study on Understanding the Effect of Questions Structure on Students' Exam Performance(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Wijesinghe, S.; Irosha, K.P.C.; Rupasinghe, T.The main challenge in evaluating students’ performance is creating effective assessments which appraises students’ learning rather than their memory power and the practice. According to education theories, creative and carefully designed assessments can clearly evaluate the degree of learning in students. “Scaffolding” which refers to the degree to which a question guides the student through the problem-solving process is a widely used method in aiding students’ learning and conceptual understanding and assessing students’ performance in Science and Technology education. The objective of the current study was to understand the impact of exam question structure on the performance of first year undergraduates specifically focusing on understanding the effect of scaffolded questions. In the current Sri Lankan science education context, there is only a limited number of research studies that are available which provides an insight into the relationship between students’ performance and question features. Current study which was designed to address this issue was conducted as a part of the Chemistry for Technology course at the Faculty of Computing and Technology, University of Kelaniya, Sri Lanka. In this study, two different structures of the same questions were given to students as a part of an in class quiz. First one was a direct question and the second version (scaffolded question) included the same question in a step by step manner and in the latter version, students had to answer several steps to solve the problem. Marks obtained for the two versions were averaged and compared to investigate whether there is any significance of the structure of the questions towards the performance of students. Average mark for the scaffolded question was 82(±20) and the direct question was 71(±35). According to the results, it was clear that the students meet a considerable difficulty in the understanding the direct questions and the scaffolding of questions results in an increase of the performance of students. According to preliminary data, it can be concluded that scaffolding of questions preferentially assist students performance at examinations and surface features such as the structure of the question can play a key role in students’ performance at the examinations. Further studies are currently being conducted to understand whether there is any specific correlation between the improvement in performance as a consequence of scaffolding with the gender, school district and students’ English literacy.Item Technology Enabled Formative Assessment in Medical Education(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Youhasan, P.; Sanooz, A.R.M.Technology enabled assessment is a novel pedagogical approach which has emerged into Medical educational practice. The main aim of formative assessment is to drive learning through constructive feedback. Kahoot is a free, real-time, game based, Web2.0 learning platform which is widely accepted to conduct formative assessment. The aim of this study was to explore the students’ perception on using Kahoot as a formative assessment tool at Eastern University Sri Lanka. A total number of 61 third year medical students participated in this cross sectional descriptive study following a pharmacology formative assessment conducted via Kahoot. The student perceptions on Kahoot experience was evaluated by a selfadministered questionnaire which consisted 10 perception statements. The participants asked to rate the statements by using 5-point Likert scale, ranging from 1 (Strongly disagree) to 5 (Strongly agree). Descriptive statistics was computed to present students’ perception. This study revealed that most of the students (83.6%) felt happy with Kahoot experience in conducting the formative assessment and (95.1%) of them recommended Kahoot for formative assessment in future. Majority of the participants (>90%) agreed or strongly agreed that Kahoot increases the focus on subjects, provides fun during learning, motivates to learn and is an effective method for active learning and providing feedback. The general outcome shown in this study derived from the students gives Kahoot a place as a tool to enhance the learning and to provide feedback. The free availability, feasibility, the technical simplicity and the enjoyable attitude from the students towards this application make this as a practical tool in Technology Enabled Assessment.Item Voltage Sag Compensation using Dynamic Voltage Restorers: A Performance Analysis(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Senevirathne, K.M.P.C.B.; Ariyawansa, K.A.; Abeynayake, P.G.; Dampage, U.Voltage sags are considered to be one of the most severe and frequent power disturbances occurring in the power system. The electronic devices used today are very sensitive to power quality, any disturbance in the power supply will negatively affect end user equipment. In order to overcome these voltage sags, implementation of a dynamic voltage restorer (DVR) has been proposed to compensate for voltage sags. Hence this technology can provide power regulation as well as power quality improvement. Electric vehicle (EV) batteries, connected in a vehicle-to-grid (V2G) system, act as the power source to the DVR, offering feasibility as well as mobility in delivering energy, thereby making it an ideal choice for energy storage used for improving power quality. This paper presents a simulation, using MATLAB, on the performance of a Dynamic Voltage Restorer (DVR) which utilizes energy from the batteries of Electric Vehicles (EV) as its power source.Item Investigation of the Degradation Processes Effect on the Properties of the Industrial Cutting Tool used in Packaging Process(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Voloshyna, A.; Romaniuk, S.The paper investigates the metal structure carbide inhomogeneity of the cutting tool made from high-alloy steel, used in industrial process of packaging candies, after its service life period. The chemical composition of steel is current: C - 2.2%, Si - 0.4%, Mn - 0.35%, Cr - 12.12%, Fe - 84.8%, Mo - 0.12%. The increased content of carbon and chromium leads to the formation of an amount of special doped carbides in the composition structure. Accordingly to the X-ray diffraction analysis, it was detected that the type of carbides conforms to Cr7C3. The amount of carbides and their size were determined with the computer program ThixometPro. As indicated by the metallographic analysis of the separate zones of the tool, the size and the number of special doped carbides differ in the images of the metal structure. Therefore, the structure of the middle part and at the edge of the operating surface were comparatively analyzed. The total amount of carbides in the middle part of the tool structure equals 14.4% of the metal matrix and reaches 8.15% at the edge of the operating surface. The structural inhomogeneity and the presence of large doped carbides were detected in the middle zone, wherein, the share of small carbides is 20.8% of the total volume of the carbide phase. There is a lack of large special carbides and the area of 69.2% carbides is not exceeding 4.75 µm at the distance up to 100 µm from the edge of the working surface. Moving further from the edge, the area and volume of carbides increase. The carbide inhomogeneity along the cross-section occurs as a result of doped carbides crushing under the stresses action during the service life. From the working surface edge to the depth dispersed carbides are lining up at an angle of 45º, forming centers of crack initiation. In virtue of the analysis, it is recommended to apply an additional hardening by the PVD method to stabilize the operating surface layer under the deformation.Item Quadcopter based Surveillance System for an Industrial Environment(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Gamlath, G.B.H.; Dampage, U.; Hewawasam, H.P.M.Y.; Midigaspe, C.S.W.; Herath, H.M.S.U.The protection of industrial infrastructure is a growing concern within industrial environments. Utilization of humans for efficient surveillance and security monitoring in a large area is inefficient since humans generally fail to maintain the concentration for longer periods of time and also due to cost involvement in employing sufficient human labor. A system architecture and design for a perimeter security system to address the aforesaid issue for large industrial facilities such as airports, seaports, logistic storage complexes and military establishments was being developed as the outcome of our research. It employs an integrated multisensory system to detect, assess and track perimeter intrusions. These sensors are integrated together into a standalone system that acquire, on processing and analyzing the probability of possible threat scenarios ignoring nuisance alarms. Upon finalizing an acquired threat, a quadcopter is autonomously dispatched to the location using an advanced location identification system, which will prioritize the locations according to the severity of threat whilst also alerting the security staff. On reaching the location, the quadcopter provides a real-time video feed while maintaining the focus on the detected target. This system is designed to operate on 24/7 in all-weather condition. A command and control center provides situational awareness to facilitate the security personnel responsible for monitoring and managing incidents. Due to the outcomes of this research, human security personnel will be provided with more relaxation in order to facilitate them to focus on tasks which demand cognitive skills. The proposed method will enhance the surveillance capacity of an installation as well as the rapid deployment capability ultimately leading to an efficient and effective security system with adequate defense in depth which is not found in conventional security systems.Item Altered Brain Wiring in Alzheimer’s: A Structural Network Analysis using Diffusion MR Imaging(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Mahadevan, J.; Ratnarajah, N.; Ranaweera, R.D.Alzheimer’s disease is a chronic neurodegenerative disorder and the most common form of dementia. It is characterized by cortical atrophy and disrupted anatomical connectivity as white matter fibre tracts lose axons and myelin degenerates. Biomarker tests are crucial to identify the early stages of the disease. It is currently a key priority in Alzheimer’s research to develop neuroimaging biomarkers that can accurately identify individuals in any clinical stage of the disease. Magnetic resonance imaging (MRI) can be considered the preferred neuroimaging examination for Alzheimer’s disease because it allows for accurate measurement of the 3-dimensional volume of brain structures. Diffusion Magnetic Resonance Imaging (DMRI), one of the methods, provides insights into aspects of brain anatomy that could never previously be studied in living humans. A comprehensive study of structural brain network in Alzheimer’s has been developed using diffusion MR imaging and graph theory algorithms, that can assess the white matter connections within the brain, revealing how neural pathways damaged in Alzheimer’s disease. A range of measurements of the network properties were calculated and the pattern of the community structure and the hub regions of the network were inspected. Global measures of efficiencies, clustering coefficients and characteristic path length confirms the disrupted overall brain network connectivity of Alzheimer’s. Relatively the same pattern of hub regions is preserved in Alzheimer’s, however, non-hub regions are affected, which indicates disease alters the internal pattern of the network especially the community structure. Modular analysis confirms this alteration and produces a different modular structure and increased number of modules in Alzheimer’s. Regional connectivity measures also indicated this change and the measures demonstrated the network centrality shifted from right hemisphere to left in Alzheimer’s. The knowledge gained from this study will support to find the strong imaging biomarkers of the Alzheimer’s disease.Item Parameter optimization of the II-VI thin-film photovoltaic tandem solar cell model of MZO/CdTe and CdS/CIGS(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Ratnasinghe, D.R.; Attygalle, M.L.C.In this simulation model we have constructed a photovoltaics tandem device with a top cell of window layer n-MZO (Mg doped ZnO), with an absorber layer of (II-VI) thin-film of p-CdTe and the bottom cell with window layer n-CdS and thin absorber layer of (II-VI) p-CIGS. Photovoltaic properties of CdTe/CIGS tandem solar cell have been studied by the Solar Cell Capacitance Simulator (SCAPS-1D) software. The thicknesses of n-CdS, p-CIGS, and the p-CdTe layers have been varied to improve the tandem solar cell device parameters such as open circuit voltage, short circuit current, fill-factor and the device efficiency. All the numerical simulations were conducted with one sun illumination condition with AM1.5G solar spectrum without any light trapping methods. In this simulation, we have observed 1. 37 V open circuit voltage, 24.5 mA/cm2 short circuit current, 85.9 fill factor and the highest efficiency value of 28.8493%. In this study we have presented a model of a tandem solar cell structure which can be used to enhance the performance of existing solar cells with the least material usage.Item Investigation of the Impact of Clay as a Bulking Agent for Food Waste Composting at a Controlled Raised-up Temperature(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Jayawardana, M.D.S.B.; Milani, Y.; Silva, C.D.; Wijesinghe, S.In agriculture, the nourishing and substantial quality of soil can be upgraded through transfiguring organic matter in food waste into humus like substance, which is called food waste composting. This is very important as food waste leads to cause odor and pollute the environment. The moisture content (MC), nitrogen content, C/N ratio and aeration in the compost material can be altered through various bulking agents used during the process. The usage of these bulking agents enhances the biodegradation of food waste and transformation of it into effective compost. Therefore, the entire composting process relies on the indispensable role of the bulking agents. Thus, this study was ultimately aimed to evaluate the influence of using clay as the bulking agent for food waste composting at a controlled high temperature (500C). Here a controlled raised-up temperature was used to lead rapid activation of thermophilic microbes. A consecutive five-day study was carried out to analyze the fluctuations of PH, MC and organic matter content (OMC) by preparing composting feedstock using clay as the bulking agent in four different weight percentages (0%, 5%, 10% and 25%). Using a Scanning Electron Microscope (SEM) surface morphology of the samples was analyzed at the initial stage and after five days composting. The analysis of physical parameters was evident that the organic matter was effectively converted to compost at 500C as all the parameters followed the corresponding gradual fluctuations which are presented at the quality compost production. According to the results, no effect was found from clay to control the PH of the composting process of food waste samples. With the increasing of clay percentage there was no significant change of PH was noticed compared to the blank waste sample. With the increment of the clay percentage of the composting feedstock, initial MC was dropped. Furthermore, by the increasing of the clay content of the samples MC was highly reduced. Similarly, OMC was also drastically decreased with the upswing of clay percentage. According to the observations, it can be concluded that clay has been acted as a good bulking agent to food waste composting. At this elevated temperature Food waste composting process had shown a significantly improvement. Presently, further studies are being carried out to further optimize the percentage of clay for food waste composting process at elevated temperature.Item Solar Thermal Energy Harnessing Using a Parabolic Trough Concentrator(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Kumara, P.D.C.; Viraj, M.P.S.; Suraweera, S.K.K.; Jayaweera, H.H.E.; Muzathik, A.M.; Ariyaratne, T.R.This paper reports the results of a study carried out in the development of a solar thermal energy harnessing plant using a parabolic trough concentrator. In the field of energy production one of the most concerned factors today is the air pollution, and it is linked with carbon and sulphur emissions from burning of fossil fuels. It is estimated that the global fossil fuel consumption will increase by 48% by 2040. In this context the Solar energy is still considered as the most prominent clean source of energy. Parabolic trough concentrator (PTC) is the most mature and commercially proven technology among the other solar thermal energy harnessing methods. The objective of this study is to design and develop a high efficiency PTC using locally available technologies and materials. The first Sri Lankan PTC thermal energy plant having dimensions of 4.5 m × 4.8 m and an aperture area of 22.3 m2 has been successfully constructed under this project and are in operation at the University of Colombo. Solar mirror films (3M 1100) pasted on stainless steel sheets are used as parabolic reflectors and they are mounted on Unplasticized Polyvinyl Chloride profiles clamped on a Galvanized Iron structure. A heat transfer fluid (Mobil Therm-605) is used to transfer the harnessed energy from PTC to the secondary energy conversion modules such as steam generator. When designing the mechanical structure, effect of the wind load was taken in to account in order to achieve the maximum stability and precision-focusing. The maximum daytime wind speed of the location of interest is around 8.3 m s-1 and the calculated maximum wind load and torque were found to be 3.19 kN and 3.64 kNm respectively for a gust factor of 1.53. The structural design was optimized using a computer simulation to bring the maximum stress below the yield point, and when stress is 23.72 MPa the total deformation was found to be 1.12 mm which does not affect the focusing significantly. The concentration ratio of the plant is 1:66 and it lies well within the range of the corresponding parameter (1:30 and 1:80) available for commercial plants. The focusing efficiency of the system is 79% which is also on par with the values available for commercial plants. However, the overall efficiency of solar thermal utilization is found to be 28.7%, hence the thermal capacity of the power plant is 5 kW. Improvements are underway to reduce the heat loss from the receiver tube. It is estimated that the overall efficiency of the system can be increased up to 65% to 70% by using evacuated glass receiver tubes.Item Finite Element Method based Triangular Mesh Generation for Aircraft-Lightning Interaction Simulation(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Vinotha, K.; Thirukumaran, S.Lightning is a natural electrical discharge process. Most common lightning strike is Cloud-to-Ground. It occurs when the negative charges accumulated at the bottom of the thundercloud traverse towards the ground to neutralize its charges with the positive earth charges induced due to the thundercloud and electrons travels along the lightning channel. The statistics shows that the commercial aircrafts directly struck by lightning strikes that are under the thundercloud once a year on average. The study of electromagnetic threat due to lightning strikes is important for flight safety and restructuring the aircraft design to mitigate direct lightning effects on the physical material of the aircraft causing damages and indirect effects on the navigation systems in it.The prime objective of this paper is to find the electric field distribution around the aircraft conductor in free space conditions under lightning scenario. For the simulation, the flash of the cloud-to-ground lightning is represented as a wave equation. Finite element method is applied to solve the wave equation for identifying potential distribution and exclusively to electric field calculations. Each of the triangular finite elements are considered and the potential at any nodes within a typical element are obtained. The equation represents the relationship between electric potential and electric field which is used to determine the electric field distribution around the aircraft surface by a numerical derivative evaluation technique from the electric potential distribution already obtained. This paper presents an aircraft-lightning interaction simulation under the thundercloud and above the ground by generating two dimensional triangular mesh using finite element method. Significant electric field distribution is observed at the sharp end points of the aircraft. Due to higher radiated electric field, the aircraft-lightning interaction may result in an adverse impact on the aircraft navigation systems and cause damage to its structures. The simulation results would be very useful for studying lightning impact on the aerial vehicles struck by the cloud-to-ground lightning. During the simulation, it was assumed that an aircraft surface is a good conductor and the effects of material properties are left for future studies.