Browsing by Author "Amarasinghe, YWR"

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item: Conference-Full-text
A 480mhz roach-2 fpga realization of 2-phase 2-d iir beam filters for digital rf apertures
(IEEE, 2016-04) Seneviratne, V; Madanayake, A; Bruton, LT; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
RF antenna array beamforming based on electronically steerable wideband phased-array apertures find applications in communications, radar, imaging and microwave sensing. High-bandwidth requirements for wideband RF applications necessitate hundreds of MHz or GHz frame-rates for the digital array processor. A systolic architecture is proposed for the realtime implementation of the 2-D IIR beam filter. This implementation employs a differential-form polyphase 2-D IIR frequencyplanar beam filter, and a corresponding circuit architecture in order to achieve the real-time computation of the input-output 2-D difference equation that defines the RF beam filter. The feasibility of real-time implementation for dense aperture arrays operating in the 0-240 MHz band using a beam filter is explored. The proposed 2-phase sampling scheme per antenna is based on a 2-D IIR polyphase structure. A digital hardware prototype is designed, implemented and tested using a ROACH-2 fitted with a Xilinx Virtex-6 Sx475t FPGA chip and a 32-channel timeinterleaved RF data converter, which support 16 antennas using 2-phase time-interleaved sampling at an FPGA clock rate of 240 MHz.
item: Conference-Abstract
Abstract of finding ideal conditions for azolla pinnata
(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 2016-04) Priyadarshani, EAC; Dissanayaka, NP; Kodikara, S; Jayasekara, AGBP; Amarasinghe, YWR
The economic and environmental costs of heavy use of chemical fertilizers in agriculture are a global concern. Sustainability considerations mandate that alternatives to Nitrogen fertilizers must be urgently sought. Biological nitrogen fixation (BNF), a microbiological process which converts atmospheric nitrogen in to a plant usable from, offers this alternative. Nitrogen fixing systems offer an economically attractive and ecological sound means of reducing external inputs and improving internal resources. Symbiotic systems such that of Anabaena – Azolla system can be used as a source of nitrogen in cropping systems.
item: Conference-Full-text
Analysis and derivation of optimum operating conditions of lapple cyclone separator by using cfd
(IEEE, 2016-04) De Silva, MSM; Narayana, M; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Cyclones are one of the most extensively used gas cleaning equipment in the industry. Current empirical model based cyclone designs and performance prediction have many limitations due to complex nature of the gas-solid flow field. Computational Fluid Dynamic (CFD) simulation could be useful to predict cyclone performance as an alternative approach. This paper represents a CFD simulation of a Lapple cyclone separator using OpenFOAM software. The flow field of cyclone was obtained by using Reynolds averaged Navier-Stockes equations combine with k-ε closure model. Flow field pressure and velocity distribution were obtained from the simulation and they were compared with the literature to evaluate the model validity. Multiphase Particle in Cell (MPPIC) method was used for the particle modeling, in which particle interactions with other particles were represented by models. Tangential gas velocity profile, pressure drop and particulate collection efficiency of cyclone obtained from the model were comparable to experimental results in the literature. Optimum values for inlet gas-solid velocity and particulate loading rate for the Lapple cyclone were obtained by this analysis. Pressure drop variation with gas-solid inlet velocity which has been obtained by this analysis could be useful to minimize the energy requirement while maintaining the required collection efficiency.
item: Conference-Full-text
Ananya - a named-entity-recognition (ner) system for sinhala language
(IEEE, 2016-04) Manamini, SAPM; Ahamed, AF; Rajapakshe, RAEC; Reemal, GHA; Jayasena, S; Dias, GV; Ranathunga, S; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Named-Entity-Recognition (NER) is one of the major tasks under Natural Language Processing, which is widely used in the fields of Computer Science and Computational Linguistics. However, the amount of prior research done on NER for Sinhala is very minimal. In this paper, we present data-driven techniques to detect Named Entities in Sinhala text, with the use of Conditional Random Fields (CRF) and Maximum Entropy (ME) statistical modeling methods. Results obtained from experiments indicate that CRF, which provided the highest accuracy for the same task for other languages outperforms ME in Sinhala NER as well. Furthermore, we identify different linguistic features such as orthographic word level and contextual information that are effective with both CRF and ME Algorithms.
item: Conference-Full-text
Application of canonical correlation analysis to study the influence of mathematics on engineering programs: a case study
(IEEE, 2016-04) Nanayakkara, KADSA; Peiris, TSG; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Mathematical knowledge is essential to improve the analytical thinking of engineering undergraduates. Exploring more information from existing academic data is an essential aspect of the educational research. The objective of this study is to explore the impact of mathematics performance on different engineering programs. The study was conducted with 626 engineering students from seven different disciplines at the Faculty of Engineering, University of Moratuwa, Sri Lanka. Canonical Correlation Analysis (CCA) was employed to investigate the relationship between mathematics courses and other engineering courses with respect to their disciplines. Results of CCA revealed that the mathematics performance in both semester 1 and 2 influences significantly on the students’ academic performance in Level 2 of the seven engineering disciplines considered. Wilk’s lambda test statistic confirmed that only the first canonical variate pair is significant for all disciplines. The squared canonical correlations of first canonical variate pair indicated that the amount of variance between the mathematics performance and academic performance in Level 2 explained varied among seven disciplines from 42% to 68%. The impact is higher from mathematics in semester 2 than that from semester 1 in all disciplines except for Material Science and Engineering discipline. The explainable variability of student academic performance in Level 2 by the canonical variate of mathematics is varied from 27% to 50% among seven disciplines. Based on preliminary analysis, it can be concluded that the performance in mathematics in Level 1 could indicate the trend towards the student academic performance in all engineering programs.
item: Conference-Full-text
Applying agile practices to avoid chaos in user acceptance testing: a case study
(IEEE, 2016-04) Padmini, KVJ; Perera, I; Bandara, HMND; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Agile practices have gained increasing popularity in Information Technology (IT), Education, Marketing, and Advertising industry, as it brings quality products into the market faster. Scrum, Lean Development, and Extreme Programming are the most commonly considered processes under the Agile umbrella. Scrum or scrum variants form a high performance, collaborative team to handle projects that are more complex. We examine the applicability of the scrum framework to a large-scale revenue management system for User Acceptance Testing (UAT). Industry believes integration and acceptance testing is not easy to perform within the scrum framework. Nevertheless, very little is explored about the acceptance testing in Agile practices. We fill this gap by empirically evaluating UAT of a complex, large-scale system (in a public sector organization) to showcase the applicability of scrum framework. While the initial UAT team consisted of 100 domain experts, no process was defined for the UAT. This made it easier to streamline the UAT into the scrum framework. Once the scrum framework was introduced significant improvements in the UAT team was experienced with improved morale, productivity, efficiency, and time to market while having a smooth flow.
item: Article-Abstract
Artificail Intelligence Based Smart Building Automation Controller for Energy Efficiency Improvements in Existing Building
Basnayake, BADJCK; Amarasinghe, YWR; Attalage, RA; Udayanga, TDI; Jayasekara, AGBP
This paper presents the design and implementation details of an Artificial Intelligent based smart building automation controller (AIBSBAC). It has the capability to perform intelligently adaptive to user preferences, which are focused on improved user comfort, safety and enhanced energy performance. The design of AIBSBAC consists of subsystems of smart user identification, internal and external environment observation subsystems, an artificial intelligent decision making subsystem and also a universal infrared communication system. Furthermore, the design architecture of AIBSBAC facilitates quick install flexible plug and play concept for most of the residential and buildings automation applications without a barrier to infrastructure modifications in installation.
item: Conference-Full-text
An Artificial Appendage for Swimming Microrobots in Non-Newtonian Fluids
(IEEE, 2021-07) Perera, KNM; Amarasinghe, YWR; Dao, DV; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Micron-scale mobile robots are being widely used in bioengineering applications, such as in a lab-on-a-chip (LOC) device, due to their capabilities of manipulation, sensing and transportation. Shear rate dependency of rheological properties of a non-Newtonian fluid enables swimming using geometrically reciprocal motion for a microswimmer. Therefore, it is not mandatory to use propulsive mechanisms that are slender in nature such as artificial flagella or cilia to generate non-reciprocal motion. We propose a design approach based on numerical simulations to select a suitable artificial appendage geometry to be used as a propulsion mechanism for a mobile microrobot. Here, the artificial appendage is considered to undergo rowing motion to generate propulsion. The fluid-structure interaction is computed numerically and three criteria are considered for the selection. In this study, a rectangular and a circular geometry are compared highlighting the proposed approach. The circular geometry showed better capability in terms of propulsion force generation, making it more suitable as a propulsion mechanism.
item: Conference-Abstract
Automated optimization and suggestion of libraries and patterns for software architectures
(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 2016-04) Pirapuraj, P; Perara, I; Jayasekara, AGBP; Amarasinghe, YWR
It is clear that code reuse is important task in software development and maintenance. The problem in code reuse is, after download all relevant code, we need to identify most relevant code among those. In this paper we use keyword search with n-gram NLP technique using GitHub Application Program Interface (API). Before search the source code, we retrieve all Repository name in GitHub belongs to particular programing language (JAVA, C++, etc.), as well as we retrieve all .java file name if we search java libraries using GitHub API. Then we compare our keyword with this list, if the keyword is extracted from Software architecture is connected word, then we will split using Apache Camel Splitter. If the particular keyword related to any project, we download the project. Otherwise using WordNet, we use synonym and repeat above process again. For further relevancy, we will use a speech recognition technique (Dynamic Time Warping (DTW)) and a NLP technique (Part of Speech Tagging (POS)). Because of this is a part of the whole research, in this paper we will consider only GitHub API use.
item: Conference-Full-text
An automatic classifier for exam questions with wordnet and cosine similarity
(IEEE, 2016-04) Jayakodi, K; Bandara, M; Meedeniya, D; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
The learning objectives, learning activities and assessment are very much interrelated. Assessment helps to evaluate students learning achievement. Poorly designed assessments usually fail to examine the achievement of intended learning outcome of a course. There are different taxonomies that have been developed to identify the level of the assessment being practiced such as Bloom’s and SOLO. In this research we have studied the use of WordNet with Cosine similarity algorithm for classifying a given exam question according to Bloom’s taxonomy learning levels. WordNet similarity algorithm depends on the extracted verbs from exam question. Cosine similarity algorithm was based on identification of question patterns of exam question. It consists of tag pattern generation module, grammar generation module, parser generation and cosine similarity checking module. This algorithm was helpful to classify the exam question where verbs were not present in exam questions. Exam questions taken from courses at the Department of Computing and Information Systems at Wayamba University were used as a basis for a performance comparison, with the autonomous system providing classifications that were consistent with those provided by domain experts on approximately 71% of occasions.
item: Conference-Abstract
Bed shrinkage in packed bed biomass combustion
(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 2016-04) Adassuriya, TL; Jayatillake, KDKY; Nupehewa, JM; Kaluhendiwela, YC; Narayana, M; Jayasekara, AGBP; Amarasinghe, YWR
This paper focuses on evaluating shrinkage of a biomass packed bed. A laboratory scale packed bed is designed to conduct experiments in batch mode. Different types of biomass i.e. Ginisiriya, coconut shells and rubber are used for the packed bed to study the behavior of bed shrinkage. The model uses inlet air stream at room temperature as the gasifying medium and a fixed batch of biomass. Ignition of the biomass batch is initiated by an external heat source. Further operation is maintained by the own heat emitted by combustion reactions, until the whole batch is finished. As the time goes height of the packed bed is decreasing due the shrinkage of the bed. Empirical data obtained from this model can be used to evaluate the bed shrinkage and temperature variations in solid phase and gas phase with time.
item: Conference-Full-text
Biodegradation of natural rubber latex by a novel bacterial species isolated from soil
(IEEE, 2016-05) Hapuarachchi, SNS; Kariyapper, SR; Gunawardana, MBDMD; Egodage, S; Ariyadasa, TU; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
A natural rubber degrading bacteria Paenibacillus lautus was isolated from soil samples of a rubber plantation in Sri Lanka. The strain was able to decompose natural rubber latex by adhesively growing on its surface using NR latex as the sole carbon source. The staining test performed using Schiff's reagent confirmed the degradation of NR latex. The Fourier Transform Infrared Spectroscopy further verified the result by showing the reduction of C=C double bonds and the presence of carboxylic acids and ketones in the polymer chain. The surface erosion images of the latex overlay surfaces obtained from scanning electron microscopy also validated the degradation process.
item: Conference-Full-text
Biomimetic flexible robot arm design and kinematic analysis of a novel flexible robot arm
(2016-04) Deashapriya, KP; Sampath, PAG; Wijekoon, WMSB; Jayaweera, ND; Kulasekera, AL; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Conventional robot manipulators have singularities in their workspaces and constrained spatial movements. Flexible and soft robots provide a unique solution to overcome this limitation. Flexible robot arms have biologically inspired characteristics as flexible limbs and redundant degrees of freedom. From these special characteristics, flexible manipulators are able to develop abilities such as bend, stretch and adjusting stiffness to traverse a complex maze. Many researchers are working to improve capabilities of flexible arms by improving the number of degrees of freedoms and their methodologies. The proposed flexible robot arm is composed of multiple sections and each section contains three similar segments and a base segment. These segments act as the backbone of the basic structure and each section can be controlled by changing the length of three control wires. These control wires pass through each segment and are held in place by springs. This design provides each segment with 2 DOF. The proposed system single section can be bent 90o with respective to its centre axis. Kinematics of the flexible robot is derived with respect to the base segment.
item: Conference-Full-text
Capacitance and tan δ measuring equipment for high voltage insulation modelling and simulation modelling and simulation
(IEEE, 2016-05) Gamage, CM; Nupehewa, JM; Kodikara, KKCS; Chathuranga, SAD; Samarasinghe, R; Lucas, JR; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Capacitance and tan δ measurements are usually carried out to check the healthiness of an insulation. Measuring equipment based on different methodologies to test insulation in cables, transformer bushings etc. are available. This paper presents the development of such a measuring equipment for a high voltage (HV) laboratory of a University. The design is divided into three parts as filter unit, test unit, and the measuring unit. These units are separately modeled and simulated using software (MATLAB and PSpice). Filter unit and the test unit are combined to analyze the results through simulation. Simulation results are used to improve the design.
item: Conference-Full-text
Categorizing food names in restaurant reviews
(2016-04) Prakhash, S; Nazick, A; Panchendrarajan, R; Brunthavan, M; Ranathunga, S; Pemasiri, A; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
There are many aspects such as food, service, and ambience that a customer would look for, when deciding on a restaurant to dine in. Among these aspects, the type of food it sells and the food quality are the most important. Therefore, when automatically rating restaurants based on customer reviews, the food aspect plays a major role. There exists some research on rating individual food items in a restaurant. However, a potential customer requires not the ranking of an individual food item, but the ranking of a particular food category in general. In order to do that, a categorization of food names is required. This paper presents two techniques for food name categorization using document similarity measurements.
item: Conference-Full-text
Cheap food or friendly staff? weighting hierarchical aspects in the restaurant domain
(IEEE, 2016-05) Panchendrarajan, R; Murugaiah, B; Prakhash, S; Ahamed, MNN; Ranathunga, S; Pemasiri, A; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
In aspect-level opinion mining, each aspect is assigned a rating based on customer reviews. More often than not, these aspects exhibit a hierarchical relationship, and the restaurant domain is no difference. With the existence of such hierarchical relationships, rating of an aspect is based on the composite score of its sub-elements. However, the influence of these sub-aspects on the score of a parent aspect is not uniform, since some sub-aspects are perceived more important than others. Therefore, when calculating the composite score for an aspect, influence of each sub-aspect should be weighted according to its perceived importance. Identifying weights for different aspects is addressed as the problem of multi-attribute weighting. However the existing approaches do not utilize the relationships between aspects to find weights. This paper presents an approach to find weights for aspects that exhibit hierarchical relationships in restaurant domain using an improved version of the Analytic Hierarchy Process (AHP), one of the Multi Attribute Decision Making Techniques (MADTs). Different aspects of the restaurant domain are modeled as a hierarchy and weights for aspects are calculated using AHP. Occurrence counts of aspects in restaurant reviews are used to obtain the relative importance of aspects. This approach provides acceptable consistency ratios for the pairwise comparison matrices obtained for each level in the hierarchy of aspects.
item: Conference-Full-text
Command governor adaptive control for unmanned underwater vehicles with measurement noise and actuator dead-zone
(IEEE, 2016-04) Makavita, CD; Nguyen, HD; Jayasinghe, SG; Ranmuthugala, D; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Unmanned Underwater Vehicles (UUVs) are being deployed in advanced applications that require precise manoeuvring close to complex underwater structures such as oilrigs and subsea installations or moving objects such as submarines. The effect of vehicle hydrodynamic parameter variations is significant in such scenarios and in extreme conditions the UUV may experience loss of control. In addition, external disturbances present in these environments degrade the controllability of the UUV. Adaptive control has been identified as a promising solution that can improve the controllability in such situations. Nevertheless, adaptive control is not widely used within the industry mainly due to the trade-off between fast learning and smooth control signals. The Command Governor Adaptive Control (CGAC) has recently been proposed as a better compromise between the two extremes. In this paper, the performance of CGAC is investigated in the presence of measurement noise and actuator dead-zone. Simulation results show that that the CGAC is highly effective in retaining good tracking performance even in the presence of significant noise within the feedback signals and an unknown dead-zone in the actuator.
item: Conference-Abstract
Comparison for pullout strength of bone joint using conventional and non-conventional drilled hole
(IEEE, 2017-05) Singh, G; Jain, V; Gupta, D; Jayasekara, AGBP; Amarasinghe, YWR
Bone screw joint plays a vital role for the sustainability of orthopaedic surgery. Before fixing screw, bone need to be low pullout strength of bone joint is a common problem which faced by the patient with passage of time. The causes of this problem initiate during the surgery. Bone faces many mechanical and frictional forces during the drilling which causes necrosis and micro cracks which can affect the sustainability the bone joint. This research gives the comparative study for pullout of bone joint using two very different concept of bone drilling. Results shows that conventional drilling causes micro cracks which will lead to low pullout strength of bone screw joint. The non-conventional technique used in this study can be an initiate to reduce the losses during bone drilling.
item: Conference-Full-text
Computation of nearshore wave set-up due to wind waves generated by tropical cyclones landfalling in Sri Lanka
(IEEE, 2016-05) Marasinghe, CK; Wijetunge, JJ; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
The hazard to coastal communities from a landfalling tropical cyclone includes high winds causing damage as well as coastal flooding caused by the storm surge. Of the four physical processes that contribute to the total surge, i.e., the wind set-up, the wave set-up, the tide and the barometric effect, this paper is concerned with the contribution from the wave set-up induced by cyclone-generated waves breaking near the shore. Accordingly, a series of numerical experiments have been performed using a spectral wind wave model to examine and quantify the wave-set-up over a range of tropical cyclone wind speeds and at five coastal locations representative of the different coastal sectors of Sri Lanka. The numerical results have also been employed to test the accuracy and reliability of the wave setup estimated from three of the analytical formulae available in the literature.
item: Conference-Full-text
computer vision based fire alarming system
(IEEE, 2016-05) Gunawaardena, AE; Ruwanthika, RMM; Jayasekara, AGBP; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Fire detection system in the surveillance system monitors the indoor environment and issues alarm as part of the early warning mechanism with ultimate goal to provide an alarm at early stage before the fire become uncontrollable. Conventional fire detection systems suffer from the transparent delay from the fire to the sensor which is looking at a point. The reliability of the fire detection system mainly depends on the positional distribution of the sensors. This paper proposes novel method of fire detection by processing image sequence acquired from a video. The proposed video based fire-detection system uses adaptive background subtraction to detect foreground moving object and then verified by the rule based fire color model to determine whether the detected foreground object is a fire or not. YCbCr color space is used to model the fire pixel classification. In addition to the motion and color the detected fire candidate regions are analyzed in temporal domain to detect the fire flicker. Some Morphological operations are used to enhance the features of detected fire candidate region. All of the above clues are combining to form the fire detection system. The performance of the proposed algorithm is tested on two sets of videos comprising the fire, fire colored object and non-fire. The experimental results show that the proposed system is very successful in detecting fire and /or flames.