Browsing by Author "Jayasekara, AGBP"

Now showing 1 - 20 of 154

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: Article-Full-text
Adapting approaching proxemics of a service robot based on physical user behavior and user feedback
(Springer Netherlands, 2022) Samarakoon, SMBP; Muthugala, MAVJ; Jayasekara, AGBP; Elara, MR
Service robots with social interactive features are developed to cater to the demand in various application domains. These robots often need to approach toward users to accomplish typical day-to-day services. Thereby, the approaching behavior of a service robot is a crucial factor in developing social interactivity between users and the robot. In this regard, a robot should be capable of maintaining proper proxemics at the termination position of an approach that improves the comfort of users. Proxemics preferences of humans depend on physical user behavior as well as personal factors. Therefore, this paper proposes a novel method to adapt the termination position of an approach based on physical user behavior and user feedback. Physical behavior of a user is perceived by the robot through analyzing skeletal joint movements of the user. These parameters are taken as inputs for a fuzzy neural network that determines the appropriate interpersonal distance. The preference of a user is learnt by modifying the internal parameters of the fuzzy neural network based on user feedback. A user study has been conducted to compare and contrast behavior of the proposed system over the existing approaches. The outcomes of the user study confirm a significant improvement in user satisfaction due to the adaptation toward users based on feedback.
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
Analysis of induction motor performance under unbalanced supply voltage conditions and its impact on the network voltage unbalance propagation
(Electrical Engineering Society (EESoc) of Department of Electrical Engineering, University of Moratuwa, 2015-12) Kattriarachchi, KG; Arachchige, VO; Kanchana, LG; Gunaratna, RDDCY; Jayasekara, AGBP
Voltage unbalance (VU) is regarded as a power quality problem of significant concern at the electricity distribution level. Influence of unbalanced supply voltages on the adverse performance of power system and its equipment is intensified by the fact that a small unbalance in the phase voltages can cause a disproportionately larger unbalance in phase currents. Naturally, three phase Induction Motor (IM) loads which are considered to be the main work horses of many industrial environments, are symmetrical devices and do not possess any inherent unbalance. However, the operation of three-phase induction motor is adversely affected by the supply source unbalance. Voltage unbalance causes a lot of adverse effects on induction motor such as Overheating, line-current unbalance, derating, torque pulsation, and inefficiency. The overheating leads to winding insulation degradation. Despite the degrading of motor performance, it has been found that the existing level of the voltage unbalance (VU) at the point of common coupling (PCC) is attenuated due to the presence of induction motor load. The following analysis shows how VU is attenuated by three phase induction motors at the point of evaluation (POE). Finally this paper presents a practical approach to evaluate VU propagation at different points of the network in terms of the Voltage Unbalance Factor (VUF) and hence the level of attenuation made by induction motor loads.
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
Application of robot autobiographical memory in long-term human-robot social interactions
(Institute of Electrical and Electronics Engineers, Inc., 2018-09) Edirisinghe, MMSN; Muthugala, MAVJ; Jayasekara, AGBP; Samarasinghe, R; Abeygunawardana, S
Robots are becoming a part of the human society. They are intended to maintain long-term social interactions with humans. A memory about each interaction partner is essential for a robot for maintaining long-term social interactions. Therefore, robot memory must possess the abilities for extracting, storing, updating and recalling information during social interactions. This work studies the application of a robot’s autobiographical memory in long-term social interactions in multi-user environments. The proposed system is capable of acquiring knowledge about users through friendly conversations and recall them during future interactions. The autobiographical memory which has been designed with a three-layered architecture is employed for storing significant information which is required for long-term social interactions. The interaction manager module has been designed as a finite state machine for managing the interaction between the robot and the user. Dialogue flows were defined for each state to communicate with the user. The system has been tested and validated by using a set of experiments.
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-Abstract
Attention level approximation of a conversation in human-robot vocal interaction using prosodic features of speech
(2017) Wickramaratne, SD; Jayasekara, AGBP
With the widespread use of robots and integration of robots into the daily human life, the communication abilities of the robots are highlighted in order to ensure smooth interaction. Domestic robots with conversation capabilities are getting an increasing demand due to the fact that modern lifestyles are driving elderly community into isolation. One of the requirements of a conversation system is to ensure that all the people involved are interested in carrying out the conversation. Humans use various physical parameters in order to determine the interest level of the speaker to ensure the conversation is interesting for both parties. The interest level estimation can be used by the robot as a form of feedback to evaluate the effectiveness of the conversation system. In order to evaluate the attention level of the user a system using the prosodic features of speech is proposed. Prosodic features can be associated with the auditory and acoustic measures. These features are important in indicating emotions and attitudes of the speaker. By using the proposed system the robot will be able to determine the interest level using the responses given by the user to the robot by analyzing the prosodic parameters of the vocal response.
item: Conference-Extended-Abstract
Automated guided vehicle for carrying carts
(Engineering Research Unit, 2023-12) Kirushan, T; Punsala, PPGP; Wimalajeewa, MHTN; Jayasekara, AGBP
The growing demand for efficient and reliable transportation solutions in industrial and commercial settings is driving the development of innovative technologies, such as automated guided vehicles (AGVs). AGVs are unmanned vehicles that can navigate autonomously along predefined paths, offering a number of advantages over traditional transportation methods, including increased efficiency, reduced labor costs, and improved safety. However, conventional AGVs are typically designed to transport specific types of materials, limiting their versatility in industries such as food and beverage, where both solid and liquid materials need to be transported. To address this challenge, we propose an AGV design capable of transporting both solid and liquid materials. It utilizes a line-following navigation system with a load type identification system and a speed controlling system, to ensure safe and efficient transportation of both solid and liquid materials. In this paper, we present a detailed overview of our AGV system design and implementation, highlighting its key features.
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.