MERCon - 2019

Permanent URI for this collectionhttp://192.248.9.226/handle/123/14700

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Now showing 1 - 20 of 147

item: Conference-Abstract
A 3D Geometry-based spatial correlation model for mimo channels
Tennakoon, P; Wavegedara2, CB
Abstract—This paper proposes a three-dimensional (3D) geometry based spatial correlation model for multiple-input multiple-output (MIMO) communication environments. In the proposed model, it is assumed that scatterers are distributed about the receiver within a spheroid, while the transmitter and receiver antennas are located at the focal points. Approximate closed-form expressions are obtained for the normalized spatial correlation coefficients of frequency non-selective Rician fading channels. As a special case, the normalized spatial functions are derived for Gaussian scatterer distribution. The closedform expressions developed are verified by the simulation results obtained using the WINNER Phase II channel model (WIM2) [17]. Furthermore, the capacity performance of MIMO channels is investigated using the proposed geometry based correlation model.
item: Conference-Abstract
Absorbing Markov Chain approach to modelling disruptions in supply chain networks
Perera, S; Bell, MGH; Kurauchi, F; Kasthurirathna, D
Recent developments in the area of network science has encouraged researchers to adopt a topological perspective in modelling Supply Chain Networks (SCNs). While topological models can provide macro level insights into the properties of SCN systems, the lack of specificity due to high level of abstraction in these models limit their real-world applicability, especially in relation to assessing the impact on SCNs arising due to individual firm or supply channel level disruptions. In particular, beyond the topological structure, a more comprehensive method should also incorporate the heterogeneity of various components (i.e. firms and inter-firm links) which together form the SCN. To fill the above gap, this work proposes using the idea of absorbing Markov chains to model disruption impacts on SCNs. Since this method does not require path enumeration to identify the number of supply chains which form the SCN, it is deemed more efficient compared to the other traditional methods.
item: Conference-Abstract
Achieving value from process intensification through better process control
(2019) Udugama, IA; Mansouri, SS; Gernaey, KV; Bayer, C; Young, BR
The continual economic drive to achieve improved process efficiencies has made process integration and intensification a main stay in process industries ranging from petrochemicals to biotechnology. However, from a process control viewpoint these integrated and intensified processes are much harder to control due to complex process dynamics and/or reduced degrees of freedom. As such, in many process industries the realized efficiency gain through integration and intensification is diminished. The objective of this article is to highlight some of the lessons learnt by the authors during their involvement in controlling intensified processes in different process industries. To this end two industrial troubleshooting case studies of a side-draw distillation column and a divided wall column are presented together with actual problems the facilities faced and how the solutions developed enabled them to be remedied within industrial limitations. This is followed by an analysis of the current process integration and intensification drive of dairy and bioprocesses. Finally the lessons learnt in these diverse process industries are summarized and its implication for process control discussed.
item: Conference-Abstract
An Activity analysis to investigate the root causes of worker productivity losses in Sri Lankan building construction projects
Karunarathna, DMTGMN; Siriwardana, CSA; Dharmawardana, MYR
Construction workers are the basic unit of the construction industry. The behaviour of construction workers varies with the time, which impacts on worker productivity. Therefore, obtaining the highest levels of performance is crucial in order to be competitive in the construction industry. The scarcity of skilled workers, increase of high rise building projects and changes in the economic and political conditions aggravated the need of seeking strategies to improve the performances of construction workers. Therefore, it is essential to investigate the productivity pitfalls, and root causes behind the worker performance losses when developing productivity improvement frameworks. Under this study, a detailed workforce assessment framework was developed for building construction projects using the Activity Analysis technique. A worker performance benchmarking was carried out for different trades to identify the differences in contract strategies of the workers. Further, root causes for worker productivity losses were identified and mapped those with the responsible parties.
item: Conference-Abstract
ACTSEA : annotated corpus for Tamil & Sinhala emotion analysis
Jenarthanan, R; Senarath, Y; Thayasivam, U
The purpose of text emotion analysis is to detect and recognize the classification of feeling expressed in text. In recent years, there has been an increase in text emotion analysis studies for English language since data were abundant. Due to the growth of social media large amount data are now available for regional languages such as Tamil and Sinhala as well. However, these languages lack necessary annotated corpus for many NLP tasks including emotion analysis. In this paper, we present our scalable semi-automatic approach to create an annotated corpus named ACTSEA for Tamil and Sinhala to support emotion analysis. Alongside, our analysis on a sample of the produced data and the useful findings are presented for the low resourced NLP community to benefit. For ACTSEA, data were gathered from twitter platform and annotated manually after cleaning. We collected 600280 (Tamil) and 318308 (Sinhala) tweets in total which makes our corpus largest data collection which is currently available for these languages.
item: Conference-Abstract
An Adapter Architecture for heterogeneous data processing in bioinformatics pipelines
Lenadora, D; Wickramarachchi, A; Meedeniya, D; Mallawaarachchi, V; Perera, L
Bioinformatics is a growing field focused on both the domains of computer science and biology. A range of bioinformatics data processing tools exists at present, which takes inputs and produces outputs in varying formats depending on the algorithms and processes being used. The undesirable situation where such processes would produce outputs that may not allow the pipelining of other processes, calls for a generic bioinformatics data format converter. Though such converters currently exist, most of them are limited to text conversions and provide limited functionality. In addition, such functions have the potential capability of supporting parallelism to increase the overall throughput. A solution that can provide the said conversion functions as well as utility functions, while processing with a high throughput via parallelism is proposed through this paper. A utility function of this system requires storing bioinformatics data locally. In addition to facilitating this, an average compression rate of 26% achieved in data storage. Evaluation of the system using a set of 7,000,000 gene data showed the maximum time consumption for retrieval as 400ms.
item: Conference-Abstract
Adaptive model predictive control with successive linearization for distillate composition control in batch distillation
Mendis, P; Wickramasinghe, C; Narayana, M; Bayer, C
This paper investigates the application of adaptive model predictive control (MPC) with successive linearization for the control of top product purity of a batch distillation column. Adaptive MPC with successive linearization can overcome the prediction inaccuracies associated with linearization of highly non-linear and dynamic mathematical model of a batch distillation column, with a lower computational load than nonlinear MPC. A binary mixture of methanol and water was selected to demonstrate the controller development, and its performance was investigated by varying MPC tuning parameters in the MATLAB/Simulink simulation environment. Results indicated that the choice of tuning parameters had a considerable influence on the MPC’s ability to track a constant set-point for the output. With the correct choice of tuning parameters, however, it is possible for the controller to track a constant set-point. The present approach is compared with nonlinear MPC in order to gain a quantitative understanding on accuracy and computational effort.
item: Conference-Abstract
Aerial Image matching based relative localization of a UAV in urban environments
Chathuranga, TS; Munasinghe, R
This paper presents a method for localizing an Unmanned Aerial Vehicle (UAV) using geo-referenced aerial images, in case of GPS failure. When flying in urban environments in low altitudes the inaccurate GPS localization has become a major problem. The proposed method fuses measurements from inertial sensors and visual odometer and perform image registration process using the images captured by the onboard down looking camera. A pre-built local orthomosaic map with geotagged aerial images is used for the registration. The problem of unreliable matches caused by the dynamic objects is addressed in our approach. The experiment results show that it is possible to localize the UAV in urban environments with a low margin of error by using our method
item: Conference-Abstract
Analysis of stability enhancement of soldier pile retaining wall
Athmarajah, G; De Silva, LIN
In construction industry, Soldier pile retaining wall with timber laggings is one of the most common retaining walls. It is relatively fastest and cheapest method. Stability of the soldier pile retaining wall is the main consideration during the design and construction period. To predict the lateral wall deformation for excavations, it is important to perform a numerical analysis, because the deflection of the soldier pile retaining wall is critical in practice. In the present study, theoretical analysis and numerical analysis were carried out to analyse the stability of the soldier pile retaining wall with the presence of surcharge. This research mainly focusing on the stability enhancement of the soldier pile retaining wall considering the factors such as, depth of embedment of the steel H-sections, spacing between steel H-sections, width of the steel H-section and soil parameters. Also, this paper presents the results of theoretical study using limit equilibrium method to assess the stability of the wall by considering the factor of safety. And, two-dimensional finite element model (FEM) of soldier pile retaining wall with horizontal timber laggings was created in Plaxis 2D software to estimate the lateral displacement of the wall and bending moment capacity.
item: Conference-Abstract
Analysis of the performance of existing wall finishers to enhance the durability of different walling materials against rain surface erosion
Galkanda, GAHH; Gunawardana, SAA; Halwathura, RU
Present building construction sector use different walling materials with different surface roughness values. With the increase of surface roughness, durability of the material reduces, while increasing the biological growth; such as moss and fungus, on walls. Therefore it was recommended wall smoothing as a sustainable solution to increase the durability of building walls. Wall care putty and lime can be identified as the most common wall finishers apply in the present construction sector. This study was conducted in order to analyze the durability performance of existing wall finishers to enhance the durability of walling materials. For the study, five materials were selected including four different walling materials; brick, cement block, cement stabilized earth block and mud concrete block, and a common wall plastering material; rough cement plaster. Ten different wall finishing mixtures; prepared by mixing lime, three different wall care putty products and cement according to the mix design, were selected as wall finishers. Prepared ten wall finishing mixtures were applied on selected walling materials and subjected to the spray erosion test which simulated ten year rain in to one hour time period. At the end of the test pit depths and scaled off material mass were measured and scaled off factor was calculated. According to the results scaled off factor is lowest in lime and in wall care putty it reduces with the increase of cement percentage. Lime is the most durable wall finisher according to the results. And wall putty layer also protect the walling material against rain surface erosion. Therefore it is concluded as existing wall finishers enhance the durability of different walling materials against rain surface erosion.
item: Conference-Abstract
Applicability of calcium carbide residues for the improvement of soft peaty clay
Ranathunga, AS; Jayathilake, LBDL; Vitharana, TH; Elpitiya, KD; Nanjitha, TGT
Most of the constructions in Sri Lanka is to be carried out on soft peaty clay. The problems with the soft peaty clay are its high-water content, being extremely compressible and having very low shear capacity. Therefore, from an engineering point of view it is very important to improve the geotechnical properties of this weak soil. Among the methods of chemical stabilization, the most common method used in world is stabilization using cement. However, using cement in such large-scale projects is unbearable for a developing country like Sri Lanka. This study is to evaluate the suitability of Calcium carbide residues (CCR) as a binder to improve soft peaty clay. Number of samples were prepared by mixing CCR with different proportions having maximum of 20% binder in soil. Improvements achieved in strength of treated peat for short term and long term were assessed by conducting unconsolidated undrained triaxial tests at 28 days and 90 days respectively. The results have shown that when the CCR content is increased, shear strength is gradually decreased in both short-term and long-term curing. However, strength improvement due to CCR is higher in long-term curing. That will be economically beneficial in projects where stabilization of soil is done in larger scale.
item: Conference-Abstract
Applicability of Enterprise Resource Planning in Human Resource Management in high-rise building construction
Bosco, AJ; Wickramasinghe, MBSM; Disaratna, V
Human Resource (HR) Management is of great significance in construction industry as it has a direct impact on the performance of construction projects. Mostly construction of high-rise buildings faces the challenge of managing its HR with the rapid design and development of them. Thus, the industry has come out with some strategies to overcome them. However, these strategies did not provide a complete solution. Therefore, construction industry needs an appropriate way to manage its HR and thus calling for an Information Technology (IT) solution which in turn is Enterprise Resource Planning (ERP) system. Consequently, the aim of investigating the applicability of ERP in managing HR in high-rise building construction became a paramount concern in this research. Accordingly, this research was adopted a qualitative approach with a set of semi-structured interviews focusing industrial professionals and ERP experts to accomplish the aforementioned aim. Subsequently, the collected data were analyzed rigorously through content analysis. The relationship between information from the literature sources and from the industry professionals with respect to main advantages of ERP system and key features of ERP system, it is recommendable to be used in managing HR through overcoming HR challenges completely in high-rise building construction.
item: Conference-Abstract
Application of Social Network Analysis (SNA) to identify communication network associated with Multi-Hazard Early Warning (MHEW) in Sri Lanka
Shehara, PLAI; Siriwardana, CSA; Amaratunga, A; Haigh, R
In Sri Lanka, there are many recurring natural hazards like floods and landslides, which often turn into crucial disasters. Therefore, there is a worldwide necessity to initiate measures to reduce disaster risk as emphasized on the Sendai Framework for Disaster Risk Reduction. In this process, Multi-Hazard Early Warnings play a vital role in which clearly defines the communication networks and enhances effective communication mechanisms. To identify the behavior of the communication network, identification of stakeholders and visualization of the network is essential. Under this study, communication networks were modelled for five frequently occurring and most critical natural hazards namely; droughts, floods, landslides, tsunami and cyclones. The stakeholder identification was done by reviewing Emergency Operation Procedures assigned for the institutions under each hazard situation. Social Network Analysis approach was used as the basis for network visualization and modelling was done using Gephi open-source software. The analyzed results were ranked based on the categories of the centrality parameter, which highlights the key stakeholders in the network. Further, the developed models were compared with the Standard Operation Procedures developed for Tsunami. The key findings of the research study can be further developed to identify and bridge the communication gap in the Multi-Hazard Early Warning Mechanism.
item: Conference-Abstract
Assessment of spallart almaras turbulence model for numerical evaluation of ceiling fan performance
Casseer, DR; Ranasinghe, RACP
Ceiling fans are a popular means of providing thermal comfort to occupants in an indoor environment, mainly in tropical countries and it contributes to a significant portion of annual energy consumption throughout the world. It is proven that using ceiling fans in conjunction with air conditioners in an air-conditioned environment can lead to higher thermal comfort at a lower cost of energy which will in turn increase the popularity of the ceiling fans in near future. Understanding the proper flow field around a rotating ceiling fan can lead to design more efficient fan blades, which can lead to significant energy savings. Analyzing these using experimental methods is both a tedious and a costly task. By using numerical methods, this can be achieved at a significant lower cost and effort. For such analyses, CFD methods using RANS equations are widely used for both indoor and outdoor conditions. For this purpose, numerous turbulence models are available, each of which would more accurately predict some cases than others. Therefore, Standard KE, Standard KW, RNG KE and Spalart Allmaras model is evaluated for a case of efficiency assessment of ceiling fans and SA model was found as the most accurate model with just 1.9% NRMSD with experimentally calculated values.
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Augmented reality in warehouse operations: possibilities and dynamics in Sri Lankan context
De Silva, P; Liyanage, HL
Large number of fields uses augmented reality in order to enhance the efficacy and effectiveness of processes. Similarly, augmented reality is an emerging trend in the supply chain management field. Growth and rapid progress in the use of augmented reality in supply chain and logistics industry are growing remarkable manner in during past few years. However, application of augmented reality technology is in infant stage in warehouse operations in the Sri Lankan context. Therefore, this paper aims to explore the possibilities of augmented reality applications and its dynamics in warehouse operations. Research paper first presents an integrated model of augmented reality applications arising from a comprehensive literature review and qualitative interviews. A questionnaire-based survey was then undertaken to test the possibilities of augmented reality applications. This mixed method research used 30 respondents. Data analysis were comprising of descriptive analysis, reliability and validity test. Finally, data were tested using Henry Garret Ranking method. Research result indicates that even though the technology is not mature enough at the moment, the potential benefits are enormous that make a promising future. Future directions for further research are discussed. This research provides a starting point for researching the use augmented reality in warehouse operations in the Sri Lankan context.
item: Conference-Abstract
Autonomous cloud robotic system for smart agriculture
Dharmasena, T; de Silva, R; Abhayasingha, N; Abeygunawardhanaz, P
Agriculture sector occupies 25.9% of the world employment. The demand for food production is rapidly increasing with the increase of world population. Developing the existing agricultural infrastructure by incorporating modern technologies will help to match this increasing demand. This paper proposes a automated system to optimally control the climate and irrigation in a greenhouse by monitoring temperature, soil moisture, humidity and pH through a cloud connected mobile robot which can detect the unhealthy plants using image processing. A fuzzy controller will control the heating and cooling system, irrigation system and humidifiers installed in the greenhouse based on the sensor readings. The mobile robot navigates through a predefined map of the greenhouse and collect soil samples to perform measurements while onboard sensors will collect the ambient climate data. A camera mounted on the mobile robot will capture the plant and detect unhealthy crops based on the colour and the texture of the leaves.
item: Conference-Abstract
Beacon placement algorithm for hybrid indoor positioning with Wi-Fi and bluetooth low energy
Nuradha, T; Gnanarathne, I; Perera, L; Denipitiyage, D; Dias, D
Indoor positioning by wireless means is of significant interest in a wide range of applications; Wi-Fi and Bluetooth Low Energy (BLE) are popular candidate wireless technologies for this. We present a novel BLE beacon placement algorithm that complements existingWi-Fi infrastructure in a hybridWi-Fi/BLE positioning system. Composite signal strength measurements thus obtained, are used to derive machine learning models for location estimation. Our results show that positioning estimates at tablelevel granularity (0.9 m 1.8 m) in a computer laboratory can be achieved with 97% accuracy. This is an improvement of 20% and 30% compared to Wi-Fi and BLE only techniques respectively.
item: Conference-Abstract
Capacity credit evaluation of wind and solar power generation using non sequential Monte Carlo simulation
Amarasinghe, PAGM; Abeygunawardane, SK
Renewable power, especially wind and solar integration to the power grid is gaining more attention nowadays. However, the contribution of wind and solar generators to the power system reliability is significantly low due to the diurnal and seasonal variations and intermittency of solar irradiance and wind speed. Capacity credit provides an idea of actual solar PV or wind capacity contribution to the power system reliability. In this paper, the non-sequential Monte Carlo simulation is used to obtain reliability curves to evaluate the capacity credit of solar PV and wind power facilities situated in Sri Lanka (SL). Moreover, SL capacity values are compared with capacity values of wind and solar generation in Brussels, Belgium which has a temperate maritime climate. The impact of power system reliability level and seasonal renewable power variations on capacity credit values are explored using several case studies. Results show that for SL, the wind capacity value significantly varies with seasons whereas the solar PV capacity value remains the same throughout the year.
item: Conference-Abstract
Comparison of damage values used in different flood modeling studies
Randil, C; Siriwardana, C; Dias, P
Estimating the economic loss caused by a flood hazard plays a major role in decision making during disaster risk reduction activities, and such studies have been carried over some major cities of the world. This paper compares the base economic values used for building and infrastructure, depth-damage curves used and the total economic loss caused by flood hazards in five such studies carried out in Colombo, Jakarta, Manila, Bangkok and Ginosa. These original studies had the data on different formats which were adopted to this study by means of normalization. The building structural damage and the contents damage of residential, commercial and industrial building types were focused on, since the largest contributions to the direct damage arises from these categories and building types. The comparisons have shown the importance of having disaggregated building economic information for commercial and industrial buildings with similar damage curves for the same building category. Furthermore, the importance of choosing a conservative depth for flood studies is stressed. The maximum inundation depth for the studies vary from 1.8 m to 10.0 m; and the lower values may produce errors in quantifying economic losses for floods with higher return periods.
item: Conference-Abstract
Compression fatigue and stress relaxation properties of single network polyacrylamide hydrogels
Udayanandana, R; Silva, P
Double-network hydrogels of different chemical compositions have been developed in recent years for specific load-bearing applications such as tissue engineering, soft robots, and stretchable electronics. The broader commercial applications of these hydrogels have been limited by high manufacturing cost and complex synthesis processes. Single network hydrogels have a potential advantage when compared to the complexity and cost of synthesis processes, although their performance and limitations under different loading conditions have not been investigated thoroughly. This paper presents the limitations of single network polyacrylamide based hydrogel on compression fatigue, stress relaxation and creep properties. Single network polyacrylamide hydrogel was selected as model material due to simple processing and availability. The optimized formulation of hydrogel was used for sample preparation. Better pressure relieving property of hydrogel was observed by stress relaxation and creep properties of the hydrogel. Developed hydrogel displayed good fatigue properties up to 13,000 loading cycle at maximum stress of 520±50 kPa and 200 mm/min crosshead speed.

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