SLIIT International Conference on Engineering and Technology [SICET]

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SLIIT International Conference on Engineering and Technology is organized by the Faculty of Engineering. SICET welcomes submissions from various disciplines, focusing on emerging trends in Engineering, Technology, and Applied and Natural Sciences. The conference will encompass research in theory, practical applications, and education. This event offers a unique platform for academics, student researchers, and industry practitioners to present innovative ideas and engage with professionals from diverse engineering fields

https://sicet.sliit.lk

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Now showing 1 - 20 of 171

Open Access
Investigating a method for rating Sri Lankan roads through identifying the factors affecting road safety
(SLIIT, 2022-02-11) Amarasingha, N; Ramanayake, D. M. S
Road safety assessment is imminent to reduce road accidents in Sri Lanka. The existing road safety assessments in other countries are inapplicable to Sri Lankan Road conditions as there are significant differences between the road conditions of Sri Lanka and other countries. This study aims to identify the governing roadside elements which are influential to the cause of accidents and can be used for road star rating. The study was conducted in three districts of Sri Lanka: Anuradhapura, Polonnaruwa and Kurunegala. The data for road characteristics were obtained through the Google Earth Web engine whereas accident data were collected from Sri Lanka Police. The variables such as road condition, road length, road width, delineation, shoulder condition, footpath, vehicle parking length, road divide status, roadside objects length, number of lanes, number of intersections, number of pedestrian crossings, and number of bus bays were analyzed to develop a Negative Binomial regression model considering the number of accidents as the dependent variable. The results reveal that six variables: number of lanes, road condition, number of intersections, road divide status, road section length and width of lane are significant towards the occurrence of accidents. Moreover, the results demonstrate the relationship between the road characteristics and the accident number which is crucial in road designing in order to reduce road accidents. The findings affirm the possibility in developing a road safety rating mechanism for Sri Lankan streets to standardize the road network with the international standards while enhancing the road conditions with reflecting to the required safety levels.
Open Access
Converter Control for Integration of Renewable Energy into the Grid
(SLIIT, Faculty of Engineering, 2022-02-11) Annakkage, U
Generation of electricity using renewable sources of energy will be the only option available to us soon. This may happen within the next two decades. In the meantime, we make the transition form traditional synchronous generator driven power systems to fully renewable energy-based power systems where the energy source is integrated through power electronics converters. We must start thinking in a new way. This presentation will address the technological challenges associated with connecting renewables to the grid through converters and the options available to meet those challenges. While the ability of the converters to respond fast is an obvious advantage, unlike the synchronous generator, it does not have a rotating mass that stores kinetic energy. The short-term overcurrent rating of the converter is much less than that of a synchronous generator unless the converter is overdesigned. Addressing these engineering challenges will be discussed in the presentation.
Open Access
Intelligent Robotics—Misconceptions, Current Trends and Opportunities
(SLIIT,Faculty of Engineering, 2022-02-11) de Silva, C. W
The concepts of “Robots” have been of interest to humans from the historical times, initially with the desire to create “artificial slaves.” Since the technology was not developing to keep up with the “dreams,” initially Robotics was primarily of entertainment value, relegated to plays, movies, stories, and so on. The practical applications started in the late 1950s and the 1960s with the development of programmable devices for factories and assembly lines, as flexible automation. However, since the expectations were not adequately realized, the general enthusiasm and funding for Robotics subsided to some extent. With subsequent research, developments, and curricular enhancement in Engineering and Computer Science and with the resurgence of Artificial Intelligence (AI), particularly machine learning, Robotics has found numerous practical applications today, in industry, medicine, household, the service sector, and the general society. Important developments and practical strides are being made, particularly in Soft Robotics, Mobile Robotics (Aerial—drones, Under Water, Ground-based—autonomous vehicles in particular), Swarm Robotics, Homecare, Surgery, Assistive Devices, and Active Prosthesis. This talk will start with a brief history of Robotics while indicating some associated myths and unfair expectations. Next it will outline key developments in the area. In particular, some important practical applications of Intelligent Robotics, as developed by groups worldwide including the Industrial Automation Laboratory at the University of British Columbia, headed by the author, will be indicated. Some misconceptions and shortcomings concerning Intelligent Robotics will be pointed out. The main shortcomings concern the mechanical capabilities and the nature of intelligence. The talk will conclude by mentioning future trends and key opportunities available in Intelligent Robotics, for both developed and developing counties.
Open Access
Design and Fabrication of a Novel Hybrid Solar Dryer
(SLIIT, 2022-02-11) Perera, C; Fernando, G; Liyanage, M
A hybrid solar dryer was designed and tested for commercial dissemination of active and passive drying methods over traditional sun drying methods. The proposed dryer employs novel features such as user controllability of the drying parameters and includes sensors and controllers for active monitoring of drying parameters. The functionality of the dryer is broadened by using logic control whereby intermittent drying patterns are introduced to the system for more efficient operation. This paper documents the design calculations and fabrication process of the dryer as well as the results of drying obtained under a controlled environment. 10 experiments have been carried out to assess the limits and potential improvements to the system which yielded satisfactory conditions with a temperature fluctuation of ±1℃ and change in %RH of ±2% at any given temperature within the specified limits. The developed system has been used for drying apples which yielded dried products from an initial weight of 346 grams to a final weight of 55 grams in 5 hours in pure convection and the same initial weight was reduced to 52 grams in 3 hours when operating in solar hybrid mode. The average energy consumption of the dryer was obtained at 300 Watts at uninterrupted solar insolation operation and 224 Watts during pure convective operation, portraying the efficient operation of the system to be eligible to be powered by a solar-powered energy storage
Open Access
Assessment of Nationally Determined Contributions of Sri Lankan Power Sector
(SLIIT, 2022-02-11) Dahanayake, A; Fernando, G; Liyanage, M
The nationally determined contributions (NDCs) aim to attend long-term temperature goals, which have been imposed by the Paris agreement to strengthen climate change efforts. Fossil fuel is the major energy source in power generation in Sri Lanka, contributing 67% of total input energies. Sri Lanka is intended to achieve 70% renewable energy in the power sector by 2030 and achieve carbon neutrality in the power sector by 2050 through its NDCs. This study analysed the NDCs in the Sri Lankan power sector. The study was carried out through Asia-Pacific Integrated Assessment Model (AIM/End-use), a recursive dynamic least-cost optimisation framework based on bottom-up modelling principles. The Sri Lankan Power sector has been categorised into a few sectors based on the fuels used in power generation. It mainly considers thermal coal, thermal oil, and hydro. It will also consider all the existing power generation technologies, committed technologies and technologies identified as candidates. A business-as-usual scenario (BAU) and three alternatives NDC were considered in this study. These NDCs include enhancing renewable energy by adding 3867 MW, converting existing fuel oil-based combined cycle power plants to natural gas and establishing new natural gas plants, and improving the efficiency of transmission and distribution network (lost reduction 0.5% compared with BAU by 2030). The study analysed the output data and confirmed the feasibility of meeting GHG emission reduction targets through consideration of selected NDCs in the time span of 2020-2030. The GHG emissions from the BAU scenario and three countermeasure scenarios were analysed in 2015-2050. The input primary energy supply was determined to compare the variation in energy with the effect of NDCs
Open Access
Nitrogen, Phosphorus and Potassium Concentrations in the Grains of Selected Rice Varieties in Sri Lanka
(SLIIT, 2022-02-11) Neththasinghe, N. A.S. A; Chandrasekara, E. D. C.T; Ekanayake, E. M.S; Madushan, N. D.R; Rathnayake, W. M. U. K; Sirisena, D. N; Suriyagoda, L. D. B
Rice (Oryza sativa L.) is the staple food for Sri Lankans, and it serves as a key source of essential mineral elements. The variation of grain nutrient concentrations as affected by genetic factors (variety, grain color and age group) are not known, and those were tested in the current study. Total of 200 rice grain samples were collected using a stratified random sampling approach, representing all agro-climatic zones in Sri Lanka. Grain nitrogen (N), phosphorus (P) and potassium (K) concentrations were measured using Kjeldahl, Colorimetric, and General methods, respectively. Grain N P and K concentrations were significantly different among rice varieties (P<0.1). Grain N concentration varied between 4-19 mg g−1 . The highest grain N concentration was recorded in Bg 307 (14 mg g−1 ) while the lowest (i.e., < 10 mg g−1 ) in Bg 367, Bg 374, Bg 358, Bg 310 and Bg 379-2. Grain P concentration varied in the range 0.6- 1.7 mg g−1 . Grain P concentration in At 406 was the highest (1.6 mg g-1), followed by Bg 307, Bg 94-1, Bg 367 i.e., >1.3 mg g-1 and the lowest in Bg 403, Ld 365 and Bg 310 i.e., < 1 mg g−1 . Bg 357, Ld 365, Bg 406, Ld 368 and Bg 310 rice varieties showed significantly lower P concentration than other varieties (P<0.1) Grain N, P and K concentrations were similar among different age classes of rice varieties (P>0.05). Moreover, grain N and P concentrations between the red and white grain varieties were similar (P>0.05). However, varieties with white color grains had higher K concentration than in red rice varieties. There was a significant correlation between grain P and K concentrations (r =0.496, P<0.001). This information would be useful when selecting rice varieties with high and low nutritional qualities and implementing sustainable nutrient management practices in rice-based cropping systems in Sri Lanka.
Open Access
Queue Length Prediction at Un-Signalized Intersections with Heterogeneous Traffic Conditions
(SLIIT, 2022-02-11) Rathnayake, I; Amarasinghe, N; Wickramasinghe, V; Liyanage, K
Increasing queue lengths while reducing average vehicle speeds is a notable criterion in intersections with heterogeneous traffic conditions. Such queue lengths vary with different intersection controls. Thisstudy aimed to estimate the queue length at un-signalized intersections with heterogeneous traffic conditions. The study was done for un-signalized intersections in Peradeniya and Weliwita, Sri Lanka and the data were collected through video recordings. The queue lengths in an un-signalized intersection with mixed traffic conditions have an instantaneous aggressive variation due to the uncontrolled movements. Thus, a time series analysis with the aid of Vector Auto Regression (VAR) model was used in order to estimate the queue length. Variables considered in this study were arrival flow rate, discharge flow rate, number of conflicts for 15 seconds time intervals as independent variables and queue length at the end of each 15 seconds as the dependent variable. For the modelling, the procedure of “Box-Jenkins” method was followed. After the confirmation of the variables are stationary, Cointegration check and Granger causality tests were done to check the cointegration between variables and the granger causality between variables. Then, VAR models were developed using 80% data from the total data set for both locations. The remaining 20% of the data set was used to validate the model using the MAE, MAPE, and RMSE error values between the actual and predicted queues. Among both models, 0.94 of higher R2 value and Durbin Watson value as 2 was obtained for the developed model using raw variables for Weliwita junction. Furthermore, the observed MAE, MAPE, and RMSE values for Weliwita model were 3,5 and 6%, respectively. Thus, the results of this study can be used to reduce traffic congestion while enhancing the safety of the users at un-signalized intersections in Sri Lanka.
Open Access
Impact of Variable Travel Time on the Solution of Vehicle Routing Problem: A Case Study of Bangkok
(SLIIT, 2022-02-11) Piantanakulchai, M; Saum, N; Shah, S
In the logistics industry, it is essential to have optimized vehicle routes for cost-effectiveness and customer satisfaction. However, most conventional studies on vehicle routing problem (VRP) do not consider the variation in travel time, leading to nonoptimal routes. This study shows the importance of variation in travel time for different times of the day and different days of the week by comparing the optimization results of vehicle routes for constant travel time and variable travel time. Two different scenarios were considered for Bangkok city, Case-1, where customers are scattered across the city, while Case-2, where customers are concentrated on a small area. It was concluded that up to 27.59% error in travel time could be obtained with an average of 12% for Case-1. At the same time, a maximum 30.85% error in travel time can be obtained with an average of 7% for Case-2. Therefore, it is necessary to consider time-dependent travel time in urban logistics route planning in Bangkok. This study also put forward a method to collect travel time data of different origin-destination pairs for different times of the day and different days of the week that can be used by any logistics company.
Open Access
Fire Safety Performance of High-rise buildings in Sri Lanka
(SLIIT, 2022-02-11) Perera, H. D. N. L; Allis, C
Fire safety is the most critical aspect of high-rise building safety. As human life is essential than other aspects, analysis of a reliable building fire safety performance is more critical than ever. Whenever an actual fire incident occurs, the active firefighting systems in the building would be activated first. As a result, it is necessary to identify the operation of active firefighting systems as well as proper service and maintenance of the systems. The research problem was identified as, people tend to fulfill the minimum fire safety requirements imposed by regulations. Therefore, the condition of fire safety performance in most highrise buildings are very poor. The aim of this research is to identify suggestions to improve the fire safety performance in high-rise buildings in Sri Lanka. Consequently, three objectives have been established to fulfill the research aim. In the first objective, building design features, human behaviors, equipment failures, and underperformance of fire regulations are highlighted as contributing factors to building fire events. The second objective evaluates fire safety precautions implemented in high-rise buildings, such as alarm activation, communication and evacuation procedures, service and maintenance periods of live fire systems, and fire evacuation drills. In the third objective, suggestions to improve the fire safety performance in high-rise buildings are recognized as, maintaining proper coordination between the fire brigade and building fire maintenance department at all times. Since the interpretivism philosophy used in this inductive qualitative research, the data was collected through conducting ten interviews with professionals who are primarily engaged with achieving reliable fire safety performance in high-rise buildings. In conclusion, recommendations such as, establish a coordination center to maintain proper coordination with fire brigade, air force and building maintenance staff and introduce a trained air force squad with helicopters and firefighting equipments can be implemented in Sri Lankan high-rise buildings
Open Access
Real-Time Embedded System for Inattentive Driver Monitoring
(SLIIT, 2022-02-11) Nalmi, R; Clerence, A.; Buddhika, P; Saranyan
One of the causes of motor vehicle accidents in Sri Lanka is driver inattention or drowsiness. In the field of intelligent transportation systems, continuous research and development are conducted to address this contemporary issue. Many approaches, such as driver assistance and drowsiness detection systems, have been proposed to overcome this fatality. The purpose of this research was to implement a product that can maximise road safety while improving the transport sector's efficiency and reliability of the logistics chain to reinforce the country's economic growth. In this paper, the correlation between the preprocessed vehicular parameters and visual features are used to analyse the driver state and make predictions of the driver's perfomance. The proposed system uses computer vision and fuzzy logic inference implemented on the singleboard computer Raspberry Pi to detect facial features and to determine the driver's drowsiness state, an ELM327 is used to read the vehicle parameters from the Electronic Control Unit (ECU) and motion sensors were used to obtain the steering angle. The data acquired is stored in a cloud platform using REST API. The database also contains driver details. The system uses a fingerprint scanner to identify the driver. An actuator was installed in the vehicle to alert the driver when the system detects inattentiveness. Overall the proposed project provided satisfying experimental results. It can be used as a solution to improve road safety and a supporting tool for the logistics sector to monitor vehicles and driver performance.
Open Access
Improving Psychological Health of Junior Professionals in the Construction Organisations in Sri Lanka
(SLIIT, 2022-02-11) Hemachandra, R; Thayaparan, M
Construction is a volatile and highly uncertain industry that faces several challenges in terms of poor image, skills and labour shortage, exposure to adverse weather, macho culture, and stressful environment. The labour-intensive nature of construction industry leads to vertical and horizontal segregation within the workforce. This study focuses on the psychological health experienced by junior professionals from the time they join until they settle down in Sri Lanka. It is vital to keep the junior professionals in their best psychological position to ensure their continuity in the job. This study investigated the risk factors that contribute to psychological health of junior professionals in construction industry and proposed strategies to address such risk factors. The research adopted a qualitative survey strategy, where 24 semi-structured qualitative interviews, including 18 junior and 6 senior construction professionals, were conducted. The research identified 26 factors under five categories such as adverse nature, apprenticeship, company culture, competition and opinions. While conforming to the existing factors from literature, the research revealed new factors too. Few to name are some common factors such as lack of leisure events, deadlines, job uncertainty; some personal factors such as human behaviour, illegal activities, personal agendas, lack of belongingness, educational background, personal bias, and lack of confidence and some dependency factors such as lack of support from seniors and task-oriented training. The senior professionals, while agreeing to most of these factors, claimed these are mainly due to the limited subject specific knowledge and lack of awareness on the nature of the job including regulations and policies by junior professionals. Appointing a mental health monitoring officer, implementing stronger human resource management policies, investing on training and development, counselling and support systems and encouraging more social activities were some of the key strategies proposed to improve the psychological wellbeing of the junior professional.
Open Access
Domestic Energy Saver
(SLIIT, 2022-02-11) Kumarasinghe, R; Abhayasinghe, N
Most of the activities in the modern world are heavy power consumers. Therefore, wasting of power is identified as a critical factor which is badly impacted the environmental and economic growth. Using electrical appliances such as ceiling fans and bulbs in the commercial and domestic environment unnecessarily is identified as a main way of wasting power. As a solution, this paper proposes the designing and producing of a power saving device for ceiling fans and bulbs. Variables such as room temperature, light intensity and the number of people present in the location were considered as parameters to control ceiling fans and bulb automatically, so as to save power by changing the speed and turning off when not necessary. This device is consisting of six main units namely a main control unit using Arduino Nano microcontroller, bidirectional visitor counter unit using two Passive Infrared motion sensors, temperature and light intensity measuring unit using a LM35 temperature sensor and a light dependent resistor sensor, an output display unit using 1604 LCD display, ceiling fan controller unit using a fan regulator that was constructed using two RC circuits, a relay module and a bulb controller unit. Ceiling fan speed and the delay time to switch off the appliances is controlled using a fuzzy logic controller. Inputs of the fuzzy logic controller are temperature difference with the set temperature, rate of change of temperature difference within a five-minute interval, difference of the number of people inside the location with the set number of people and the rate of change of number of people within a five-minute interval. It was observed that, for the test cases, an average of 318Wh per day could be saved from a single bulb and a ceiling fan while avoiding unnecessary usage of appliances.
Open Access
Variation of Microwave Leakage Exposure Levels Close to a Microwave Oven with Load, Container Type and Time.
(SLIIT, 2022-02-11) Suraweera, T; Jayaratne, C
Nowadays people are living in a rush world and most people seek efficient methods to complete their day to day work with less time. Microwave ovens are the best option to cook foods as well as for reheating precooked foods. Microwave ovens use radio frequency (RF) electromagnetic waves around the frequency 2.4 GHz for cooking and reheating food by dielectric heating or high frequency heating. Many scientific reports have been confirmed that eating microwave food is not a risk, because radio waves cannot ionize foods. But the problem is exposing to the leakage microwave radiation when operating the oven. Authorized bodies such as International Commission on Non-Ionizing Radiation Protection (ICNIRP) as well as Federal Communications Commission (FCC) have been published limitations for exposure to these RF waves. The limited plane wave power density for a microwave oven is 50 W/m2 at any point 5 cm away from the oven. Over exposure to these RF waves with high plane wave power densities may lead to health effects such as cataracts in the eyes, infertility, and brain tumors. In this study, leakage microwave plane wave power densities were evaluated by using spectran HF6065 spectrum analyzer under three situations with newly brought microwave oven. In the first study variation of RF levels at 40 cm from the front glass of the microwave oven with the load (water) were evaluated, In the second study RF levels around the microwave oven for same load kept in plastic and ceramic containers were evaluated separately and, in the third study, time variation of the power density at a distance 40 cm in front of the microwave oven for a duration of 180 s was evaluated. Results in the first study show that negative correlation (r=-0.6136) between the load and leakage microwave emission around the oven as well as maximum average plane wave power density of (512.78 ± 0.01) mW/m2 with no load inside the oven and maximum average plane wave power density with the load is 195.06 ± 0.01 mW/m2 with 100 ± 1 g of load kept in a plastic container with mass 68 g. For the second study considerably low RF levels were recorded when using the ceramic container than plastic container. Results for the third study show that microwave emission around the oven is fluctuating rapidly with time and it can be varied between 0.01 mW/m2 and 108.48 mW/m2 . Evaluated maximum RF plane wave power density among all three studies was (677.84 ± 0.01 mW/m2 ) and this value is 1.35 % of maximum permissible leakage level for a microwave oven as well as it is found that frequency of the microwave radiation is also varying when it is operating. However, authors would like to request not to stay close to a microwave oven when it is operating, especially children and pregnant women because they are more sensitive for non-ionizing RF radiations.
Open Access
Experimental investigation of concrete-filled and bare 6082-T6 aluminium alloy tubes under in-plane bending
(SLIIT, 2022-02-11) Kamaris, G. S; Gkantou, M; Kansara, K. D; Bin Al, S
The application of aluminium alloys in construction sector is increasing owing to their excellent corrosion resistance, light weight and attractive appearance. However, one of the main disadvantages of aluminium alloys is the low elastic modulus, which may cause a stability issue in aluminium structural members. The performance of aluminium tubes can be improved by filling concrete within them. Research on the flexural behaviour of concrete-filled aluminium alloy tubes is limited. This paper presents an experimental study on the behaviour of square and rectangular concrete-filled and bare aluminium tubular sections subjected to in-plane bending. Total 20 beams were tested, including 10 concrete-filled aluminium tubes (CFAT) and 10 bare aluminium tubes (BAT). The hollow aluminium tubes were fabricated using 6082-T6 alloy and filled with 25 MPa cylinder compressive strength concrete. The material properties of aluminium were measured by tensile test of coupons. It is shown that the flexural strength, stiffness and ductility of square and rectangular BAT flexural members was remarkably improved by the infilled concrete and the improvement is more pronounced for the thinner aluminium sections. Due to absence of design standards for CFAT beams, in this study the design rules available for concrete-filled steel tubular flexural members in the Eurocode 4 are considered by substituting the mechanical properties of steel with those of aluminium alloy. It is demonstrated that the proposed design rules provide good predictions of the flexural capacity of CFAT.
Open Access
Construction Project Risk Management for Performance Improvement (Polgahawela-Pothuhera-Alawwa Integrated Water Supplying Project)
(SLIIT, 2022-02-11) JAYASINGHE, S. M. I. A.; WEERAKKODY, F
Construction risk management can be defined as the avoidance or the reduction of possible harmful incidents or actions in a construction project. It can be one of the most important factors in a construction project. Depending on the nature of the project, types of risks can be very wide in its range. Understanding the risk factors and the proper management of them, can lead a project to be completed on schedule, avoiding budget overruns whilst ensuring the safety and welfare of all the project participants. This research aims to identify the risks and their possible impacts on a specific construction project. The selected project is the construction of the Polgahawela-Pothuhera-Alawwa Integrated Water Supplying scheme located in the North-Western province of Sri Lanka. Risks categorized under the different sectors such as financial management, technical, quality, health, and safety, environment, social, legal and political were considered in the research but limited to the construction phase of the project. The methodology for this study is based on ISO 31000, which includes risk identification, risk analysis, risk evaluation and risk mitigation. To identify the relevant risks of the project, a structured interview using a questionnaire was conducted among selected project participants. In making the assessments founded on the responses received, weighted credits were assigned based on the academic and professional qualifications of the respondents. The responses were utilized in this manner to develop a listing of risk and its consequences. This highlighted the more severe risks enabling recommendations to be made to mitigate and manage such risks. The risk management process together with knowledge from previous literature was used in making recommendations to mitigate and manage risk towards project performance improvement. It should be noted that the findings could be of benefit to future contractors associated with similar projects.
Open Access
A Study on Local Air Pollution Due to Transport Emissions in Kandy City
(SLIIT, 2022-02-11) Yatigammana, S; Fernando, G; Liyanage, M
Air pollution has become one of the greatest challenges that the world is facing today. According to World Health Organization (WHO)there are 4.2 million annual deaths due to outdoor air pollution. Furthermore, about 90% of global population breathe polluted air. The most harmful cause of outdoor air pollution is recognized to be unorganized traffic management. In the instance of Sri Lanka, Kandy city has been recognized as crucial where necessary actions are required to be taken. This study presents harmful emission values produced by a daily count of vehicles entering the city alongside respiratory diseases and illnesses recorded. Detailed analysis provides pollutant emissions due to unorganized traffic management within Kandy city concentrating over locations from Getambe Junction to Kandy Clock tower and from the city centre towards Mahaiyawa Tunnel and Ampitiya Junction (locations are pinned on figure 1). Calculation of pollutant factors are intended to be done using three main methods namely, Tier 1, Tier 2 and V/C ratio method aided by vehicle fuel type, fuel efficiency, travelled distance and carriageway congestion values. Emission values for pollutants Carbon monoxide (CO), Nitrogen oxides (N2O, NOX) and Sulphur dioxide (SO2) were identified in this study along with PM2.5 and PM10 values. It was to be seen that, over 100,000 vehicle cross Kandy city limits on both weekdays and surprisingly higher values in weekend with each carriageway within the city resulting over a 65% of congestion value. With 31% of daily trips being travel to work, the public transport system fails to deliver its purpose efficiently and effectively. With unorganized traffic management, stagnant and slowmoving vehicles tend to pollute 41% more SO2 and 14% more NOX gasses above global standards affecting the first five kilometers from the city center, which claimed to facilitate the zone of highest quality of life. Current records show PM2.5 values in Kandy to read above 50μg/m3 and PM10 values to be as high as 100μg/m3.
Open Access
Support Vector Machine Based an Efficient and Accurate Seasonal Weather Forecasting Approach with Minimal Data Quantities
(SLIIT, 2022-02-11) Chandrasekara, S; Tennekoon, S; Abhayasinghe, N; Seneviratne, L
Climate change makes a big impact in our daily activities. Therefore, forecasting climate changes prior to its actual occurrences is important. Even though highly accurate weather prediction systems throughout the world are available, they require mass amounts of data exceeding thousands of data points to obtain a significant accuracy. This study was aimed at proposing a Support Vector Machine based approach to carryout seasonal weather predictions up to thirty-minute intervals, the results of which would be considerably effective with respect to predictions carried out with models trained with annual datasets. The model was trained utilizing a dataset corresponding to the district of Kandy which consisted of 136 samples, 20 features, and 5 labels. By means of carrying out numerous data preprocessing steps, the model was trained, and the relevant hyperparameters were optimized considering the grid search algorithm to yield a maximum accuracy of 86%, once tested via the k-fold cross validation. The performance of the Support Vector Machine was also then compared for the same dataset with that of the K-Nearest Neighbor algorithm which consumed relatively fewer computing resources. An optimal accuracy of 61% was observed for this model for a K-value of 27. This approach supported the concept of a Support Vector Machine’s ability to perceive time series forecasts to a relatively higher degree and its ability to perform effectively in higher dimensional datasets with smaller number of samples. As per the future work, the Receiver Operating Characteristic analysis is proposed to be carried out to evaluate the performance of the model and the dataset size is proposed to be further enhanced to a maximum of a thousand samples to yield the best performance results.
Open Access
Review on Use of End-Area-Rule for Volume Calculations in Highway Pavements
(SLIIT, 2022-02-11) Wanasinghe, G. I; Thennakoon, P. G; de Silva, N. A; Kalugamuwa, I. M
Volume estimation of highway pavements is very important in planning and design of highways, in order to calculate the amount of materials and hence for cost analysis. It is also used to investigate the workmanship and quality of construction in post analysis. End area rule is the simplest and most widely used technique in volume calculation as it can be used with the cross sections generated at a suitable interval. The theory being used for road segment between two consecutive cross sections assuming there exists a linear variation of cross sectional areas within the interval. Validity of the application of end area rule depends on this assumption and accuracy also varies when the linear variation does not exist. This study was carried out to analyze the validity of the application of end area rule due to the non-linearity of variation of cross sectional areas in highway pavements. The scope of the study was limited to straight segment with rectangular cross section. Road width and height of the cross section were selected as variables and the volumes were compared using different models with coaxial centroids and skew sections. Numerical models with different angles of centroids were used in the study and the results were verified using digital models created with AutoCAD 3D software. The interval between sections was also investigated and it was determined that the perpendicular distance between sections should be used in the end area rule. Finally it was concluded that the area variation is not linear when there are more than one variable affect the cross section. The modification to end area rule was also developed in order to increase the accuracy.
Open Access
Spatial Patterns and Temporal Trends of Rainfall Seasonality in Sri Lanka
(SLIIT, 2022-02-11) Amarasinghe, H.G.K.H.; Basnayake, B.M.L.A.
Understanding and knowledge of rainfall variability is necessitated for agricultural planning, flood mitigation activities, and water resources planning and management. Like other rainfall characteristics seasonality of rainfall is also spatio-temporally specific which has not been evaluated to Sri Lanka. In this study, seasonality in rainfall over Sri Lanka was analyzed using the seasonality index (SI) proposed by Walsh and Lawler. Rainfall data at 39 raingauge stations for the period 1988-2017 were collected to obtain the annual monthly rainfall cycles. The SI, a measure of annual rainfall distribution, was used to identify different rainfall regimes. Southwest and central highlands covering the stations Baddegama, Pelawatte, Kudawa, Deniyaya, Mawarella, Mapalana and Beausejour (lower) were identified as “equable with a definite wetter season”. Skirting to the definite wetter season was the “rather seasonal with a short drier season” regime surrounding the Colombo, Ratmalana, Nuwara Eliya, and Bandarawela. The region centered on Mannar received the most rain in three months or less. Markedly seasonal with a long drier season is in the eastern extending from Pottuvil to Trincomalee and in the northern part of the country above Puttalam and Maha Illuppallama except the surrounding of Mannar. Intermediate region to SI classes “rather seasonal with a short drier season” and “markedly seasonal with a long drier season” was designated as “seasonal”. However, the seasonal rainfall contribution, i.e., in NEM (Dec.-Feb.), IM1 (March-April), SWM (May-Sep.), and IM2 (Oct.-Nov.), and the annual monthly rainfall profiles confirmed the presence of sub-regimes within the identified rainfall regimes. Non-parametric Mann-Kendall test and Sen’s slope were applied to identify the temporal changes in SI. Approximately, half of the country showed strong trends in the SI. Sixty one percent of the area including the northern part of the country surrounding Jaffna and the definite wetter region in the southern corresponds to the decreasing trend in seasonality.
Open Access
Relationship between procurement systems and payment methods in assuring financial safety in Sri Lankan building projects
(SLIIT, 2022-02-11) Niriella, A; Gamage, I
The Construction industry is a place where the parties to a project frequently face various risks throughout the project life cycle. Financial risks are one of the aforementioned risks that have a significant impact on parties, and more studies should be conducted to investigate the possibility of minimizing these financial risks and assuring the financial safety of projects. Thus, this research aims at identifying the relationship between procurement systems and payment methods towards assuring the financial safety of construction projects. Researchers selected government funded building projects to limit the scope because such projects frequently deal with financial risks. Frequent financial risks in a Government Funded Building Projects (GFBP) were identified as material shortages, fluctuation of inflation rate, legislation changes. The study used a mixed method approach, and data was gathered through semi structured interviews and questionnaires. Data was analyzed using manual content analysis and basic statistics. Common procurement systems and payment methods available in a GFBP were identified through interviews. Accordingly traditional, design and build, management oriented and collaborative procurement systems were identified and lumpsum, measure and pay, Guaranteed Maximum Price (GMP) and cost reimbursement were identified as payment methods. Furthermore, findings revealed that there are six common combinations between procurement systems and payment methods in GFBP. The identified combinations were further tested for their ability to minimize financial risks of GFBP and it was revealed that the combination consisting of Lumpsum with Design and Build was the best combination to assure financial safety in GFBP. Other combinations are traditional with measure and pay, design and build with lumpsum, design and build with GMP, management oriented with lumpsum, management oriented with measure and pay. Ultimately, a framework has been developed by harmonizing all the research findings in which parties can select the most viable combination to assure the financial safety of their project.