MERCon - 2018

Permanent URI for this collectionhttp://192.248.9.226/handle/123/14699

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2018 Moratuwa Engineering Research Conference (MERCon) [Pre Text]
(IEEE, 2018)
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3d full-field deformation measuring technique with optics-based measurements
(IEEE, 2018-05) Randil, OPC; Mallikarachchi, HMYC; Chathuranga, D
Full-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%.
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Ac-dc multi-port domestic distribution interface
(IEEE, 2018-05) Gunaratne, T; Wijesinghe, D; Wijerathne, K; Binduhewa, PJ; Ekanayake, J; Chathuranga, D
The rapid development of PV systems and energy storage techniques have created opportunities for further evolvements on the utility side. On the other hand, the number of conversion stages required to feed inherent and converter controlled dc loads from the ac grid have compromised the efficient operation of the power grid. The proposed multi-port distribution interface combines dc and ac power resources and dc and ac loads with minimum number of power electronic conversion stages thus increases the energy efficiency. This paper presents the development of the converters and the controller functions of the proposed interface which is to be implemented in a domestic scale. Along with the individual simulations the paper includes several case studies where different behaviors of the overall system are discussed.
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Adopting design thinking practices to satisfy customer expectations in agile practices: a case from Sri Lankan software development industry
(IEEE, 2018-05) Prasad, WMDR; Perera, GIUS; Padmini, KVJ; Bandara, HMND; Chathuranga, D
While the application of agile principles leads to better project success, some projects still fail due to insufficient understanding of client’s exact requirements. Agile teams have recently started adopting Design Thinking (DT) practices to better understand what is in customers’ mind. We explore suitable DT practices to satisfy customer expectations in agile teams using inductive reasoning. We first formulated a conceptual framework based on a literature review. We then conducted a set of interviews with fifteen domain experts from ten IT service organizations. Interview findings were then analyzed using the Straussian grounded theory. Customer journey, story mapping, prototypes, POC, and customer profiling were determined to be the most suitable methods to identify the needs of customers. Moreover, practicing human-centered approach through workshops, discussions, team communication, and end-user interaction through UAT were also identified to be effective. We further classified the best practices into five categories as customer’s real need identification, transforming customer’s real needs into pilot solutions, visualizing the pilot solution for customer feedback, idea generation for the pilot solution, and brainstorming. Based on these findings, we also derived a framework to achieve customer satisfaction through the adoption of DT in agile-base projects.
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Analysing Non-Isothermal Curing Behaviour of Natural Rubber Compounds By Mathematical Modelling of Oscillating Disc Rheometer Curves
(IEEE, 2018-05) Weragoda, VSC; Samarasekara, AMPB; Chathuranga, D
This study investigates a novel way of analyzing the rheometer curves obtained from an Oscillating Disk Rheometer (ODR) for predicting the non-isothermal curing characteristics of a rubber compound. A mathematical function is proposed to predict the change in the observed rheometer torque as a function of the temperature to model the state of cure under transient temperature conditions. This was achieved by modeling the rheometer curve with the aid of six temperature dependant parametric constants. The proposed function was observed to accurately describe, the shape of the torque rate at any given temperature. The characteristics variation of the parametric constants too have been briefly examined.
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Analysis of impediments hindering fmcg companies from rail freight distribution in Sri Lanka
(IEEE, 2018-05) Kumarasinghe, SC; Bandara, YM; Chathuranga, D
As rail road multimodal transportation integrates economic, social and environmental advantages, rail freight transportation is considered as a vital and effective distribution solution for both bulk and non-bulk cargo in several countries of the world. But all most all of the freight in Sri Lanka is distributed using road transportation modes. Even the minor proportion of freight on rail mostly consist bulk cargo types. As the FMCG (Fast Moving Consumer Goods) which is a type of non-bulk cargo, is distributed fast to dispersed locations throughout the country, using rail as a main leg of distribution can be a potential opportunity. Unfortunately none of the FMCG companies in Sri Lanka today are using rail freight distribution and the main focus of the research is identifying the impediments that hinder the these companies to shift from road to rail. The research revealed five major impediments; lack of collaboration among government and private sector, cost consciousness, doubts on risk and control, unreliability of Sri Lanka Railway (SLR) services and facilities and lack of information available about rail freight distribution. Both SLR and FMCG companies must address these issues and stakeholder consultation is essential for the developments to rail industry to support FMCG distribution.
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Analysis of the dimensional change of woven fabrics from loom state to finished state
(IEEE, 2018-05) Kandemulla, KASM; Maduwantha, ARL; Fernando, EASK; Niles, SN; Jayawardana, TSS; Chathuranga, D
Dimensional change of a woven fabric is a challenge in woven fabric production. The phenomenon originates from the dimensional instability of the fabric. Shrinkage is a combined result of numerous factors such as relaxation, dyeing, finishing and the effect of machinery. The significance of this problem has been investigated by several researchers, who focused mainly on the geometry of the fabric during the weaving phase (loom stage) only. To investigate the dimensional changes that occur within a particular woven structure, a number of fabric samples were sent through various finishing processes such as, washing, dyeing & finishing, under the laboratory conditions. The changes were measured either in terms of dimensional change or EPI and PPI values. Using the experimental data and theoretical analysis, a mathematical model has been developed and validated. However initially the focus is laid on plain woven fabrics and it is expected to be further extended to the other woven structures as well.
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Analysis on centrality index of air network
(IEEE, 2018-05) Prasani, S; Fernando, A; Chathuranga, D
Air transport network plays a major role in catalyzing globalization through facilitating the movement of goods and people between countries. This study analysed the connectivity of the airline network of the national carrier of Sri Lanka and identified the critical airports and their impact to the network. The study considered the network of Sri Lankan Airlines for the analysis and used flight stats data for data collection. Dubai International Airport (DXB), Delhi International Airport (DEL) and Kuala Lumpur International Airport (KUL) had the highest degree centrality in the network, indicating strong connectivity with other nodes in the network. Thus the most critical airports in the network. While Gan International Airport (GAN) and Seychells International Airport (SEZ) indicated the lowest degree centrality. Degree centrality of the nodes in the networked changed when critical airports were removed from the network. Combaitre International Airport (CJB) is having the highest closeness centrality indicating the ease of movement between the nodes. Removing the critical airports with from the network affected the closeness centrality score of the nodes.
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Assessing impact of concessionaires on sea ports
(IEEE, 2018-05) Gunasekara, H; Bandara, Y; Chathuranga, D
Concession has been acknowledged as an important tool for port authorities to retain control of ports by contracts out the management and operation to the private sector for a specific time period [1]. This study focuses on developing a model to measure the concessionaire impact on port performance and efficiency using the pre and post privatization data. Parameters such as Crane rate, Elapsed rate, Total TEU and Ships handled were used as variable for the assessment and the secondary data were collected from a website of Australian government. The statistical report called ‘Waterline’ provides the latest data available on stevedoring productivity and landside performance of five Australian major port terminals for the period of 1990 to 2007. The samples were drawn as panel data by indicating 90 observations to test the model. The collected data was analyzed using Multiple Regression analysis and “Minitab 16” as the analytical software. Analysis revealed a continuous improvement in the developed model and the findings of the research indicated that crane rate of ports with the concessionaire are higher than that of ports without concessionaire while that value of Elapsed rate was lower than that. From observation in this study, a decision can be made that the increased trend in transferring government port operations and asset to the private sector suggests that public ports can benefit from greater private sector participation than fully privatization.
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Assessment of cost of unserved energy for Sri Lankan commercial sector
(IEEE, 2018-05) Colambage, DP; Perera, HYR; Chathuranga, D
The investments for the improvements of power system to fulfill the energy requirements of electricity customers need to meet the reliability improvement targets. Thus, it is essential to obtain a clear and accurate assessment of Cost of Unserved Energy as an input to the power system planning process. Sri Lanka is currently using an approximated value of Cost of Unserved Energy calculated in 2002 considering only the Industrial Sector. It is important to update this value. This research was conducted to assess the Cost of Unserved Energy based on consumer survey method. The survey and analysis parts are conducted in three separate categories as Industrial, Commercial and Residential. This paper presents the results for Commercial sector, separately for momentary, planned and unplanned non-momentary interruptions. It is expected that the results of this study helps the power sector to provide a better service, taking the views of the customers and the national importance of electricity as an esential input for economic growth.
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Autonomous transmission line inspection and fault detection system
(IEEE, 2018-05) Ranaweera, PS; Alahakoon, DC; Prabhashwara, KSS; Lakmal, AMGVI; Chathuranga, D
Power transmission network is the most critical part of a power system due to its connectivity with generation and distribution stations. Though it is a riskier employment to carry out the routine inspections of the transmission lines manually, the task of inspection is imperative to the continuous operation of the power system. However, the new trend of transmission line inspection is based on extracted details of the lines by means of Remotely Operated Vehicles (ROVs) traversing through them. This paper proposes a method being tested by a prototype for traversing alone the transmission conductor, inspecting the line through real time video streaming, detecting faults and pinpointing them through Geo Tagging. Automated transmission line inspection and fault detection is proposed to carry out through image processing and sensory data acquisition. Radio Frequency (RF) technology is the main communication mechanism between the operator and the ROV. This technology will expand the remotely operating distance of the ROV. Furthermore, a mechanism was developed to enable the robot to cross over from one span to another in the transmission network which include suspension type insulators.
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Beyond site material handling and transportation in large-scale construction projects
(IEEE, 2018-05) Abeysinghe, AMGP; Waidyasekara, KGAS; Melagoda, DG; Chathuranga, D
There is a significant contribution of materials to be handled, transferred, and used; further, large logistics operations are related to transporting, storing, moving, and reloading in large scale construction projects. Thus, the research aims to investigate issues that occur beyond the site, material handling, and transportation in large-scale construction projects. Accordingly, extensive literature was synthesized to identify the usage of materials in large-scale construction projects, their significance, and procedures of material handling and transportation. This study adopted a qualitative research approach by selecting a multiple case study strategy. Five largescale construction projects in Colombo Metropolitan area were selected and semi-structured interviews were conducted with three different levels of site personnel from each case study. Finally, the gathered information was analyzed using computerbased content analysis and further supported by data collected through observations. The outcomes disclosed various issues in material handling and transportation with respective causes and possible solutions to minimize identified issues in large scale construction projects. Accidents, adverse weather conditions, lack of material handling equipment, lack of labors, improper packing systems, misplace and steal of materials, lack of pre-arrangements, bulk quantities, limited site area, delay in taking approvals, improper supervision and unawareness of the handling process were identified as common material handling and transportation issues. It was identified these can be mitigated by proper supervision, providing a manual to handle each material, labeling material, maintaining good communication with laborers and arranging a gate pass system. Further, recommendations for improving material handling and transportation were provided for industry practitioners.
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C-jae: 3 dof robotic ankle exoskeleton with compatible joint axes
(IEEE, 2018-05) Weerasingha, AH; Pragnathilaka, ADKH; Withanage, WPK; Ranaweera, RKPS; Gopura, RARC; Chathuranga, D
This paper proposes a three degrees of freedom (DOF) robotic ankle exoskeleton with compatible joint axes, named C-JAE. The device consists of three separate units to achieve triplanar motions. The plantarflexion-dorsiflexion and inversion-eversion are externally powered, whereas internalexternal rotation is passively supported. C-JAE is capable of complying with the functional and ergonomic requirements of the biological ankle joint. This is achieved by accurately mapping exoskeleton axes of rotation with the oblique axes of rotation of talocrural and subtalar joints of ankle. All mechanisms including the drive units are located anterior to shank and foot segments to carry out robotic rehabilitation and/or to provide locomotion assistance for humans having mobility disorders. Control experiments were conducted to assess aptitude of C-JAE to carry out ankle rehabilitation exercises. The results verified potential benefits of the proposed design to generate desired movement patterns of daily activities while providing power-assistance.
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Calibrating and validating vissim microscopic simulation software for the context of Sri Lanka
(IEEE, 2018-05) Jayasooriya, N; Bandara, S; Chathuranga, D
At present, majority of traffic management initiatives are mostly based on trial and error procedures, where no proper traffic theory or simulations are involved. When considering the context of Sri Lanka, the use of traffic simulation software has been the newest addition for the traffic engineering field. However, the outputs obtained from VISSIM traffic simulation software can become unrealistic, if no proper calibration is conducted for the local context. Therefore, the aim of the research is to develop a calibration procedure and identify representative values for parameters required for VISSIM micro simulation software to suit the local Condition. Based on the findings of the literature review, 9 key parameters were identified for calibration purposes of VISSIM, which are further reduced to 5 key parameters based on the sensitivity using statistical tools. These 5 parameters were further simulated in order to identify optimum input values, resulting in minimum percentage error for the difference between observed and simulated queue lengths. The calibrated parameters were successfully validated using 23 signalized intersections in Colombo and Gampaha Districts and these parameter values can be used in future traffic and transportation micro simulation studies.
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A case study on the retention tanks in the walawe ganga river basin, Sri Lanka.
(IEEE, 2018-05) Thilakarathne, JASI; Wijayaratna, TMN; Chathuranga, D
Village tanks have been used for irrigation purposes from a longer period of time and its behavior as a cascade system can be considered as an efficient methodology towards a sustainable water management system. Though it’s not vividly addressed in recent studies, some tanks are present in a cascade system with a mere intention of retaining water for the downstream tanks and, are being called as retention tanks. Nevertheless, in the present day, those are being used to fulfill human water needs instead of their initial use as retention tanks. Due to this reason, the overall working capacity of village tank cascade systems is being diminished. And in this case study, a methodology is proposed to identify retention tanks using five cascade systems in Walawe ganga river basin.
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Challenges faced by agile testers: a case study
(IEEE, 2018-05) Padmini, KVJ; Kankanamge, PS; Bandara, HMND; Perera, GIUS; Chathuranga, D
In the agile framework developers and testers are part of a hyper-productive, self-organizing team. Testing scope changes when user stories are added, updated, or deleted. Moreover, test cases need to be re-written or update when user stories change or removed from the sprint, which wastes time and makes agile testers frustrated. Furthermore, the mini-waterfall model adopted within a sprint could develop unwanted stress in agile testers. Despite these challenges little seem to be understood about the challenges faced by agile testers. We fill this gap by closely studying the challenges faced by agile testers in a multinational IT services organization. We first set up a forum for agile testers to discuss their challenges, malpractices, and best practices. We then conducted an online survey based on the findings from the forum and literature review. Through this, we identified 15 challenges and best practices to overcome those 15 challenges. We further conducted a set of interviews with the subject matter expertise to identify a suitable set of solutions such as conducting retrospective in a fun and engaging way, managing story lifecycle using collaborative tools, setting up ground rules for geographically distributed teams, and introducing innovative sprints.
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A clinical decision support system for drug conflict identification
(IEEE, 2018-05) Nilan, Y; Sellahewa, D; Fernando, S; Gamage, L; Meedeniya, D; Chathuranga, D
Adverse drug reactions (ADRs) are common major issue in the health-care system that occur mainly due to the interactions among different medicines prescribed for different diseases. Other than the interactions among different medicines, life habits such as food consumption, alcohol consumption and smoking also affect the occurrence of ADRs. The main goal of this research is the identification of ADRs occur due to the interactions of medicines. The proposed solution identifies conflicts among different medicines and diseases based on rules defined using formal methods and provides alternative treatment paths. This study is supported by a mobile application that can be used by both medical practitioners and public users. The outcome of this research can be used by medical officers as a clinical decision support system to assist the prescription process.
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Clustering sinhala news articles using corpus- based similarity measures
(IEEE, 2018-05) Nanayakkara, P; Ranathunga, S; Chathuranga, D
News aggregators help readers to handle large numbers of news items in a convenient manner by collecting them into a single place with meaningful groupings. Such news aggregators/clusters are available for English and some other popular languages. However, no such tools are available for Sinhala language. To address this void, this paper presents a system to collect news articles published across the web and group related articles using corpus-based similarity measures. Despite the simplicity of the technique and morphological richness of Sinhala, we achieved very promising results that prove the viability of the presented technique.
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Computational modeling of perovskite structured methylammonium lead iodide as a solar absorber
(IEEE, 2018-05) Nanayakkara, HATV; Sewvandi, GA; Chathuranga, D
Halide Perovskite materials play a prominent role in solar cell industry as they comprise with advanced photovoltaic properties. Research is mainly based on the objective of investigating basic fundamental properties of CH3NH3PbI3 using Viana Ab-Initio Simulation Package(VASP). Before go to the experimental data analysis we have simulated fundamental photovoltaic properties of Methyl Ammonium Lead Iodide using computational method. CH3NH3PbI3 perovskite undergoes a phase transition between orthorhombic, tetragonal and cubic around 165K and 327K. Then the most stable structures are tetragonal and cubic phases. Therefore, in this research we have focused to study the basic crystallographic orientations, Energy band gap variation, Density of states in P, S orbitals and effective mass values of cubic and tetragonal phases in Methyl Ammonium Lead Iodide. Basic Density Function (DFT) theories like Local-density approximation of Kohn-Sham theory, Exchange correlation functional are basically used for theoretical calculations in this computational study.
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Continuous integration and continuous delivery pipeline automation for agile software project management
(IEEE, 2018-05) Arachchi, SAIBS; Perera, I; Chathuranga, D
Agile practices with Continuous Integration and Continuous Delivery (CICD) pipeline approach has increased the efficiency of projects. In agile, new features are introduced to the system in each sprint delivery, and although it may be well developed, the delivery failures are possible due to performance issues. By considering delivery timeline, moving for system scaling is common solution in such situations. But, how much system should be scaled? System scale requires current system benchmark status and expected system status. Benchmarking the production is a critical task, as it interrupts the live system. The new version should go through a load test to measure expected system status. The traditional load test methods are unable to identify production performance behavior due to simulated traffic patterns are highly deviated from production. To overcome those issues, this approach has extended CICD pipeline to have three automation phases named benchmark, load test and scaling. It minimizes the system interruption by using test bench approach when system benchmarking and it uses the production traffic for load testing which gives more accurate results. Once benchmark and load test phases are completed, system scaling can be evaluated. Initially, the pipeline was developed using Jenkins CI server, Git repository and Nexus repository with Ansible automation. Then GoReplay is used for traffic duplication from production to test bench environment. Nagios monitoring is used to analyze the system behavior in each phase and the result of test bench has proven that scaling is capable to handle the same load while changing the application software, but it doesn’t optimize response time of application at significant level and it helps to reduce the risk of application deployment by integrating this three phase approach as CICD automation extended feature. Thereby the research provides effective way to manage Agile based CICD projects.

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