MERCon - 2022

Permanent URI for this collectionhttp://192.248.9.226/handle/123/18494

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item: Conference-Full-text
3D full-field deformation measurement using stereo vision
(IEEE, 2022-07) Sarma, LS; Mallikarachchi, C; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Measuring 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-text
Active and passive based hybrid cell balancing approach to series connected lithium-ion battery pack
(IEEE, 2022-07) Ekanayake, EMAGNC; Hemapala, KTMU; Jayathunga, U; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Lithium-ion battery (LiB) technology is extensively used in energy storage systems (ESS), electric vehicles, and portable devices. Optimal cell balancing techniques for a battery management system are essential for the operation of the Li Battery. This paper proposes a new passive and active-based hybrid cell balancing technique integrating switched resistor balancing technique and switched capacitor balancing technique to achieve less balancing time and less power dissipation with simple control and hardware. The proposed system has been mathematically modeled and simulated, and the results show a 30% increase in the balancing time compared to the conventional capacitive balancing technique. Also, the control algorithm can adaptively operate to achieve better performance of the circuit. The simulation is done in the MATLAB Simulink environment.
item: Conference-Full-text
Adversarial learning to improve question image embedding in medical visual question answering
(IEEE, 2022-07) Silva, K; Maheepala, T; Tharaka, K; Ambegoda, TD; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Visual Question Answering (VQA) is a computer vision task in which a system produces an accurate answer to a given image and a question that is relevant to the image. Medical VQA can be considered as a subfield of general VQA, which focuses on images and questions in the medical domain. The VQA model’s most crucial task is to learn the question-image joint representation to reflect the information related to the correct answer. Medical VQA remains a difficult task due to the ineffectiveness of question-image embeddings, despite recent research on general VQA models finding significant progress. To address this problem, we propose a new method for training VQA models that utilizes adversarial learning to improve the question-image embedding and illustrate how this embedding can be used as the ideal embedding for answer inference. For adversarial learning, we use two embedding generators (question–image embedding and a question-answer embedding generator) and a discriminator to differentiate the two embeddings. The questionanswer embedding is used as the ideal embedding and the question-image embedding is improved in reference to that. The experiment results indicate that pre-training the question-image embedding generation module using adversarial learning improves overall performance, implying the effectiveness of the proposed method.
item: Conference-Full-text
An alternative method to reduce the construction cost and the reinforcement usage of the rigid pavement near the toll plaza in expressways.
(IEEE, 2022-07) Kasthurirathne, H; Edirisooriya, UJW; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
In expressways, a toll plaza structure is a conspicuous structure, where vehicles frequently brake and accelerate within a small distance. As a result, the pavement deteriorates at a higher rate compared to normal bituminous pavement. Hence, toll lanes near toll plazas are constructed as heavy reinforced concrete rigid pavements. In Sri Lanka, the same technique is used for rigid pavements near expressway toll plaza structures. Due to the high cost of this method, the objective of this research is to present a cost-effective way with acceptable efficiency by comparing methods and technologies that other countries use to construct rigid pavement in toll lanes. To achieve this objective, the used design methods and the material cost of the ColomboKatunayake expressway at Peliyagoda and Seeduwa toll entrances, Dambokka and Kurunegala toll entrances in the Northern expressway are discussed in this study. The study revealed that the replacement of reinforced concrete pavements in the above toll gates with Ultra-thin continuously reinforced concrete pavement can decrease the material cost by 7.97% at Peliyagoda, 36.08% at Seeduwa, 5.66% at Dambokka, and 5.48% at Kurunegala. Used pavement design and the proposed ultra-thin continuously reinforced concrete pavement are analyzed using the Finite Element Analysis (FEA) method through ABAQUS 2020 software. Obtained results indicated that it is more economical to use an ultra-thin continuously concrete pavement with steel fiber than the currently used method.
item: Conference-Full-text
An analytical approach for designing turbo expanders for organic rankine cycle
(IEEE, 2022-07) Ratnayake, RMSA; Bandara, RMAT; Sandaruwan, PHPL; Wijewardane, MA; Ranasinghe, RACP; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
ORCs (Organic Rankine Cycles) are becoming widely attractive for waste heat use since they facilitate power generation from low thermal content supplies. ORC may be optimized in various ways after determining the appropriate operating working fluid and design parameters. This article introduces a new design approach to produce a turbo expander demonstrated for a 1kW ORC utilizing R245fa as the working fluid. The obtained initial dimensions of the rotor were evaluated using performance criteria commonly used in turbo-machinery designing and the best results were selected after conducting several iterations. The inlet tip speed U 5 is considered as the primary design variable since it is restricted by mechanical stress considerations. The results obtained from the rotor analytical study are then utilized for stator, volute, and diffuser designs.
item: Conference-Full-text
Analyzing the optimum contact angles of water droplets to mitigate the e-field stress on polymer insulator
(IEEE, 2022-07) Antony, AD; Arachchi, BATNKB; Gunasinghe, JB; Gunawardana, M; Samarasinghe, R; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
The water droplets present in the insulator surfaces cause variation in the e-field along the insulator surface. Variation in the e-field can lead to flashover and accelerate the ageing of the insulator and ultimately will end up in the breakdown of the insulator. The contact angle of water droplets is also a factor that determines the e-field variation. In this study, the effect of the contact angle of water droplets is analyzed using a simulation approach for different cases considering both pure and contaminated outdoor polymer insulators. The results show that the optimum range of contact angles of water droplets can be concluded as 70 to 120 degrees for a pure insulator, while the optimum range for a polluted insulator can be given as 70 to 100 degrees.
item: Conference-Full-text
Application of lstm and ann models for traffic time headway prediction in expressway tollgates
(IEEE, 2022-07) Phan, QTN; Mondal, M; Kazushi, S; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Traffic time headway is essential to support decision-making in safety management, capacity analysis, and service provision. Many studies on the time headway distribution on highways and urban roads serve two primary purposes. The studies that serve the latter purpose, service level, have not been given adequate attention. In fact, at manual toll stations, traffic congestion is still a severe problem. Predicting the time headway at toll stations becomes extremely meaningful when the service providers can allocate resources reasonably, minimizing waiting time in off-peak periods and utilizing resources during high-demand periods. This study applies two modern machine learning methods to predict the time headway at Niigata toll stations, Japan, namely Long Short-term Memory (LSTM), which only requires simple input of time series, and Artificial Neural Network (ANN), which requires some additional external features. The data set is the time headway of vehicles on expressways, along with the weather information and the vehicle’s average speed for five working days. There needs to be a trade-off between computation time, input data complexity, and model accuracy. Thus, tollgate operators could choose a suitable model based on their actual situation.
item: Conference-Full-text
Application of novel evolutionary algorithms for analyzing the impact of integrating renewables on the adequacy of composite power systems
(IEEE, 2022-07) Amarasinghe, G; Abeygunawardane, S; Singh, C; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
The adequacy evaluation of modern renewable-rich power systems tends to be a computationally challenging task due to variations of renewable power generation. Recently, more computationally efficient evolutionary algorithms and swarm intelligence-based methods are utilized for evaluating the adequacy of power systems. In this paper, the authors have proposed a wind and solar integrated composite system adequacy evaluation framework using an Evolutionary Swarm Algorithm (ESA). The system failure states which have a higher probability of occurrence are explored using the ESA to estimate the adequacy indices of the system. The wind and solar power generation are modeled using a clustering-based method considering their annual effective power output. Moreover, the correlation between the system load and renewable power generation is modeled in the adequacy evaluation framework. Using the proposed framework, several case studies are conducted on the IEEE Reliability Test System to analyze the impact of integrating renewables on the adequacy of composite systems. The results show that wind generation tends to improve system reliability than solar due to its higher availability. In addition, the equivalent capacities of wind and solar generators are found to be 125MW and 215MW against a 50MW hydro generator.
item: Conference-Full-text
Appraising vulnerabilities on elders and built environment of aging-in-place in tropics using infrared thermography
(IEEE, 2022-07) Rajapaksha, I; Jayasekara, R; Siriwardana, C; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Demographic shifts due to the burgeoning ageing population and increasing global temperatures are synchronized societal challenges of the future. People living in low and middle-income countries are ageing much faster than richer countries and over the next three decades, ageing is predominant in Asia. People ageing in low-income communities of the tropics will become more vulnerable to heat with limitations and conditions of the houses they live. Thus, the study appraises the vulnerabilities of elders and the built environment of aging in place in the tropical city of Colombo, Sri Lanka. The selected cohort is permanently residing in a low-income community. Infrared thermal imagery analysis of elders is evident for a mean skin temperature of 34.9° C, which is 1.9° C above a healthy adult. Mean skin temperature further increases in elders living in detached houses. Moreover, the houses demonstrate poor ventilation, and overheated interiors with less usable floor area and windows. Additionally, the elders are suffering from long-term illnesses and their income restricts treatments. Thus, the study portrays an overarching social injustice status of ageing population in cities in Sri Lanka, as elders prefer aging in place. Thus, it highlights the significance of physical attributes of built environment to ensure healthy aging in warming climates.
item: Conference-Full-text
Aspect detection in sportswear apparel reviews for opinion mining
(IEEE, 2022-07) Rajapaksha, S; Ranathunga, S; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Manufacturers and brand owners apply sentiment analysis techniques on customer reviews to identify customer opinions on their products and services. Sentiment analysis at the document level or sentence level does not provide a complete view of the customer opinion because customers may express their opinion on different aspects of the product or service within a single review. This issue has inspired aspect-level opinion mining. Two core tasks are involved with aspect-level opinion mining: aspect detection and aspect-based sentiment analysis. This research is aimed at the first task - aspect detection. The focused domain is sportswear apparel, which has been largely overlooked in the field of opinion mining. Accordingly, this paper presents a new dataset produced with manual annotations by domain experts, according to a newly defined aspect taxonomy. This research compares the performance of a set of pre-trained language models for the considered task, and achieves state-of the-art performance for sportswear apparel reviews using a novel ensemble method.
item: Conference-Full-text
Assessment of the optimum dimensions for cobble-type paving blocks using finite element modeling
(IEEE, 2022-07) Kumarage, NR; Jayasinghe, C; Perera, KPH; Kariyawasam, KKGKD; Herath, S; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
A numerical model was developed to investigate the deflection of permeable interlocking concrete blocks. In this study, the acceptance of paving blocks with extensive plan areas was tested. ABAQUS finite element modeling software which is commercially available was used and a static, linear perturbation analysis was carried out. Three alternative block dimensions were determined according to the guidelines provided in ASTM C936 and were modeled. Mesh sensitivity analysis was carried out on each alternative to identify the optimum global element size for each model. Although all three tested models resulted in vertical deformations less than the threshold, the results indicated a positive association between the exposed plan area and the vertical deformation. Finally, it can be concluded as the SLS 1425 recommended paving block dimensions resulted in the most favorable results.
item: Conference-Full-text
Benchmarking energy and water consumption of supermarkets in Sri Lanka
(IEEE, 2022-07) Senanayake, SMCP; Wijewardane, MA; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Buildings are responsible for about 40% of global energy consumption, 42% of global CO 2 emissions and about 30% of global fresh water consumption. Therefore, the importance of energy and water consumption benchmarking in buildings has become a major objective for governments and relevant authorities, in order to reduce the energy and water consumption by the buildings. Energy consumption benchmarks for commercial sector, hospitality industry, apparel industry and tea processing industry have been already developed and are available for Sri Lanka. However, electricity and water consumption benchmarking for retail supermarkets have not been established yet. Therefore, during this study, electricity and water consumption benchmarking for Sri Lankan retail supermarkets were estimated and proposed. According to the analysis, electricity consumption benchmarks were obtained as 780.0 kwh/year/m 2 per sales floor area and 465.4 kwh/year/m 2 per total floor area. Moreover, mean specific electricity costs were obtained as 19,465.90 Rs/year/m 2 per sales floor area and 11,621.20 Rs/year/m 2 per total floor area, provided that electricity cost is calculated per GP 2 tariff structure of Ceylon electricity board. In addition, water consumption benchmarks were obtained as 246.5 L/year/m 2 per sales floor area and 137.2 L/year/m 2 per total floor area. Moreover, a building energy simulation model was developed using eQUEST simulation software, to obtain the specific electricity consumption and average annual electricity consumption breakdown of the retail supermarkets. Eventually, the results obtained from the simulation model were validated against the results obtained from the numerical model, and then compared and verified with the international benchmarks established for retail supermarkets.
item: Conference-Full-text
Bottom-up cost modeling of lithium-ion battery cells for electric vehicle applications
(IEEE, 2022-07) Hewawasam, D; Subasinghe, L; Karunathilake, H; Witharana, S; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Lithium-ion Batteries (LIBs) have come a long way with various improvements to make them more efficient, compact, and safe while simultaneously enhancing the energy density and cycle life. If it is possible to improve the technicalities to lower the cell cost by indicating some potential solutions, the economic issues in LIBs automotive applications can be addressed. This study intends to approach a bottleneck solution for pure Electric Vehicle (EV) cost reduction. The BatPaC 5.0 modeling tool is used to examine different cell chemistries (NMC811-Graphite(Gr), NCA-Gr, LFP-Gr, LMO-Gr, and 50%/50%NMC532/LMO-Gr) and determine the accuracy of the hypothesis made on the effect of positive electrode coating thickness of LIBs, on the cell cost, gravimetric energy density and volumetric energy density in high volume production. Using the above assumption, it is obtained that doubling the coating thickness of the positive electrode from 60 to 120 μm, reduces the cost in all cell types. But the highest by ~20% in LFP-Gr. And it emerges that increasing the positive electrode coating thickness of LIBs, lowers the cell cost whilst improving the gravimetric energy density and volumetric energy density. Therefore, the positive electrode coating thickness can be considered a crucial parameter in cell cost reduction.
item: Conference-Full-text
A capacitated vehicle routing problem model for stationery industry
(IEEE, 2022-07) Liyanage, RN; Thibbotuwawa, A; Edirisinghe, PM; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
This paper aims to present an optimization solution for the distribution of stationery products with a seasonal demand pattern. The problem is structured as the capacitated vehicle routing problem is one-to-many with multiple products, where each customer has a variety of product types and demands. It is observed that yearly distance has varied by 43% between the season and off-season periods and the total distance savings throughout the year is around 40%. A mixed-integer linear programming model was used to give an optimal solution and the Gurobi solver was used to arrive at the solution. The objective of the research is to determine the appropriate number of vehicles used to complete the delivery process in both seasonal and off-seasonal periods, together with the route sequence of every vehicle, such that the distance-related costs are minimized with effective vehicle capacity utilization.
item: Conference-Full-text
Case studies on blast behaviour of glass façades: Sri Lanka easter bombings
(IEEE, 2022-07) Jayaweera, GCS; Hidallana-Gamage, HD; Baleshan, B; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Sri Lanka Easter attacks were done by coordinated suicide bombers on 21 st of April, 2019. This paper investigates the damages to the glass façades due to the explosions that occurred inside the five-star hotels, Shangri-La, and Kingsbury in central Colombo. It is evident from previous explosions that the blast-related injuries are mainly caused by the free-flying glass fragments. Laminated Glass (LG) will provide better resistance to explosions that occur outside the building if they are properly designed to be held on the supporting structure. Because, if the blast pressure enters the building, it will cause severe damage to the building elements while creating injuries to the occupants. However, when an explosion occurs inside the building, damage to the building elements and occupants will be severe if the blast pressure cannot escape from the confined building premises easily. Therefore, both of these aspects should be considered when designing glass façades for a credible blast load. LG has better blast resistance than monolithic glass. This paper presents a comprehensive review on the effect of the Easter bombings on glass façades and some design strategies which can be recommended for blast-resistant glazing with the evidence from available literature and design standards.
item: Conference-Full-text
Challenging factors to adopt circular economy in sustainable food supply chain
(IEEE, 2022-07) Pannila, N; Jayalath, MM; Thibbotuwawa, A; Perera, HN; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Even though circular economy has captured global attention recently with its sustainable implications, the adoption takes a much slower approach, particularly in the food supply chain. This study attempts to identify challenging factors that hinder the adoption of circular economy in the food supply chain. A total of 17 challenging factors are identified via a systematic literature review. The challenging factors were grouped into 6 categories: economic, social, institutional, technological and informational, supply chain, and organizational. Literature frequency analysis method combined with an article-level research citation metric of field-weighted citation impact was employed to prioritize the challenging factors based on the literature importance. Thus, the findings reveal that cost efficiency considerations, less enforcement of legislation and regulations, and no long-term shared vision among stakeholders are the three most critical challenging factors to adopt circular economy in the food supply chain. The findings will help managers, decision-makers, practitioners, and governments to formulate policies and strategies to implement circular practices in the food supply chain effectively.
item: Conference-Full-text
Chest X-Ray Caption Generation with CheXNet
(IEEE, 2022-07) Wijerathna, V; Raveen, H; Abeygunawardhana, S; Ambegoda, TD; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Chest X-rays are provided with descriptive captions that summarize the crucial radiology findings in them in natural language. Although chest X-Ray image captioning is currently done manually by radiologists, automating it has received growing research interest in the medical domain because it is a tedious task and the high number of medical reports that are to be generated daily. In this paper, we propose an automatic chest X-ray captioning system consisting of two main components: an image feature extractor and a sentence generator. We did our experiment in two approaches. First, we tried using LXMERT, which is originally designed for question answering, as the sentence generator in our model combined with the Faster RCNN model. Second, we used CheXNet and a memory-driven transformer as the feature extractor and the sentence generator respectively. We trained and tested our model using the IU chest X-ray dataset. We evaluated the model using the BLUE, ROUGE-L and METEOR metrics which shows the CheXNet based approach outperforms the latter models.
item: Conference-Full-text
Chitosan-graphene oxide composite membrane for methylene blue removal
(IEEE, 2022-07) Dissanayake, NSL; Pathirana, MA; Wanasekara, ND; Nandasiri, GK; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Textile wastewater accommodates many toxic organic contaminants which could potentially threaten the ecosystem if left untreated. Methylene blue is a toxic, nondegradable, cationic dye which is reportedly found in significant amounts in the textile effluent stream as it is widely used to dye silk and cotton fabrics. This study reports an investigation of methylene blue removal using a composite membrane fabricated using chitosan and graphene oxide. The fabricated composite membrane was characterized using Scanning Electron Microscopy, FTIR Spectroscopy, Raman Spectroscopy, UV vis spectroscopy, and X ray Diffraction. The isotherm modelling conducted confirmed a maximum adsorptive capacity of 179 mg/g which was well fitted with the Langmuir isotherm model indicating a homogenous monolayer adsorption.
item: Conference-Full-text
Climate elasticity of runoff in kalu and Kelani river basins in the wet zone of Sri Lanka
(IEEE, 2022-07) Wijekoon, T; Rajapakse, L; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
This study estimates the climate elasticity of runoff concerning precipitation and evaporation, in Kalu and Kelani river basins in the wet zone of Sri Lanka. The Ellagawa subbasin of Kalu river and Hanwella subbasin of Kelani river were selected for the assessment. The non-parametric estimator was selected based on the simplicity to assess the climate elasticity of runoff in the selected wet zone basins under current climate scenarios. The rainfall elasticity and evaporation elasticity were estimated for prevailing climate conditions. At the same time, the climate elasticity under synthetic climate change scenarios was assessed using a hydrological model. The HEC-HMS rainfall-runoff model was selected based on the accessibility, flexibility, reliability, and data requirements to simulate streamflow. According to the model results, climate change results in causing -41% to 31% change in runoff in the Kalu river basin and -49% to 23% change in runoff in the Kelani river basin under synthetic climate change scenarios that have been developed for the period of 2016-2035 considering the predicted precipitation and evaporation changes comparative to the baseline period of 1986-2005.
item: Conference-Full-text
A comparative study to evaluate the effectiveness of different structural forms for medium-rise apartment buildings
(IEEE, 2022-07) Wijekoon, S; Jayasinghe, T; Herath, S; Herath, A; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
The rapid urban migration and the infrequency of spaces in megacities have become a challenge for all most all countries. To fulfill the housing requirements of the ever-growing population with the scarcity of valuable lands, the best solution is to come up with high-rise or medium-rise apartment buildings. Even though there are different structural forms that can be incorporated into high-rise apartment structures, most of the time structural designers select based on their experience and approach which are not effective all the time. The structural design for a given structure should be optimum in terms of structural performance and associated costs. Since wind and seismic forces govern the design of high-rise structures, those lateral forces are significant to be studied. So, this analytical study was carried out to evaluate the effectiveness of six different structural systems of 20-story RC (Reinforced Concrete) structures under the effect of wind and seismic loadings including a moment-resisting frame as the base model, four wall frame structures and a frame-tube structure. Models are compared based on the parameters such as maximum top storey displacement, inter-storey drift ratios, member forces and moments utilization, seismic induced base shear and human perception levels of lateral acceleration.

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