Browsing by Author "Kulasekere, E. C"

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Open Access
An algorithm for energy driven cluster head rotation in a distributed wireless sensor network
(Colombo, 2005-12-15) Gamwarige, S; Kulasekere, E. C
Wireless sensor networks (WSNs) consists of large number of inexpensive, low-power, sensors that can be placed in an ad hoc fashion to form a communication network. Efficient techniques for inter sensor communication and information gathering is critical for prolonging the lifetime of the sensor network. Clustering provides an effective way for extending the lifetime of a sensor network. In this paper we propose a distributed and energy driven clustering algorithm where the cluster heads are selected based on relative residual energy level of sensors. Furthermore the cluster head candidacy selection phase, and the cluster head candidacy rotation among phases is triggered only when any of cluster heads energy drops below a dynamic threshold computed by the algorithm. As a result, the overheads in the inter sensor communications will be reduced and thereby the proposed algorithm will favor more powerful nodes over the weaker ones to prolong the lifetime of the entire sensor network in both homogeneous and heterogeneous sensor networks. The results have shown that the the proposed algorithm performs better when compared to existing algorithms such as LEACH, SEP, HEED and ANTCLUST based on the Percentage Node Alive (PNA) and the First Node Dies (FND) metrics.
Embargo
An analytical framework for cluster distribution of EDCR class of algorithms in Wireless Sensor Networks
(IEEE, 2009-12-28) Gamwarige, S; Kulasekere, E. C
Energy Driven Cluster-Head Rotation (EDCR) class of algorithms are energy aware distributed clustering techniques for effective ad hoc deployed Wireless Sensor Network (WSN) organization. The application of this class of algorithms requires the setting of salient parameters at the design stage of the WSN to achieve desired results. Two such parameters which should be known in advance are the cluster density and the distance between neighbouring cluster heads (CHs). In this research we analyze the effect of algorithm design based on these two parameters. Simulation techniques are given to support and verify the analytical results.
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Application of the edcr algorithm in a cluster based multi-hop wireless sensor network
(IEEE, 2006-10-18) Gamwarige, S; Kulasekere, E. C
The energy driven cluster head rotation algorithm proposed in (Gamwarige, S and Kulasekere, E, 2005) and analyzed in (Gamwarige, S and Kulasekere, E, 2006) is based on a single hop communication model where the data messages from each cluster head (CH) node is sent directly to the base station (BS). As a result when the wireless sensor network (WSN) dimensions are large, the nodes located far away from the BS die much faster. In this paper a method of extending the lifetime of the WSN based on a multihop communication model applied to the EDCR algorithm is proposed. The modified EDCR (EDCR-MH) relays all CH to BS messages via other CH nodes by computing a shortest path based on local heuristic information. Further, the EDCR-MH also has provisions to minimize the burden due to excessive data relay on nodes closer to the BS. The results indicate that the proposed algorithm out performs algorithms like under similar conditions
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Blended induction program for electronic engineering freshmen
(Sage Publications, 2018-10) Dayawansa, I; Wijenayake, C; Edussooriya, C; Samarasekara, T; Karunasekara, C; Dias, D; Samarasinghe, K; Kulasekere, E. C; Rodrigo, R; Dayananda, N
This paper presents learning and teaching experiences gathered from an induction program conducted at the Department of Electronic and Telecommunication Engineering, University of Moratuwa, Sri Lanka for newly enrolled undergraduate students. The induction program, named as the pre-academic term, was an experimental effort to explore the applicability of blended leaning concepts to enhance the learning experience of Engineering freshmen, while enabling smooth transition from high school to university education. In addition to standard lectures, an integral part of the program was in-class demonstrations, where electronic circuits were assembled from scratch on a printed circuit board and demonstrated using a projected camera during the lectures. Organization, learning objectives, brief description of the example projects are presented along with a summary of formal student feedback. More than 85% of the freshmen indicated that the induction program helped them to smoothly begin the university education. A qualitative assessment in the laboratory work indicated that about 98% of the students successfully completed the assigned hands-on activities.
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A cluster based energy balancing strategy to improve Wireless Sensor Networks lifetime
(IEEE, 2007-08-09) Gamwarige, S; Kulasekere, E. C
Wireless Sensor Networks (WSNs) have been of interest due to its many areas of application. The lifetime of the sensor bed is of crucial importance for the successful deployment of such networks. Many algorithms have been proposed based on clustering and cluster head (CH) rotation to improve the lifetime of WSNs. EDCR [1] and EDCR-MH [2] are two such algorithms that have shown promising results. The lifetime of the entire sensor bed can be significantly improved if the energy associated with a sensor node is depleted at the same rate irrespective of its location with respect to the Base Station (BS). This research proposes a new algorithm for CH selection and rotation that incorporates the desirable features of both EDCR and EDCRMH together with a modified minimum distance communication between CH and BS. The algorithm is capable of balancing the energy depletion rate of sensor nodes across the entire sensor bed irrespective of their node locations. Unlike previous algorithms, the proposed algorithm can be applied to significantly larger sensor beds while maintaining the lifetime performance. Analytical models are presented to identify salient parameters of the proposed algorithm. Simulation results are provided to illustrate the applicability of the algorithm. The results indicate that the lifetime of the entire sensor bed is improved over existing algorithms.
Open Access
Cluster density of dependent thinning distributed clustering class of algorithms in ad hoc deployed wireless networks
(Hindawi, 2012-01-01) Gamwarige, S; Kulasekere, E. C
Distributed clustering is widely used in ad hoc deployed wireless networks. Distributed clustering algorithms like DMAC, HEED, MEDIC, ANTCLUST-based, and EDCR produce well-distributed Cluster Heads (CHs) using dependent thinning techniques where a node’s decision to be a CH depends on the decision of its neighbors. An analytical technique to determine the cluster density of this class of algorithms is proposed. This information is required to set the algorithm parameters before a wireless network is deployed. Simulation results are presented in order to verify the analytical findings.
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Conditioning and updating evidence
(Elsevier, 2004-04-01) Kulasekere, E. C; Premaratne, K; Dewasurendra, D. A; Shyu, M. L; Bauer, P. H
A new interpretation of Dempster–Shafer conditional notions based directly upon the mass assignments is provided. The masses of those propositions that may imply the complement of the conditioning proposition are shown to be completely annulled by the conditioning operation; conditioning may then be construed as a re-distribution of the masses of some of these propositions to those that definitely imply the conditioning proposition. A complete characterization of the propositions whose masses are annulled without re-distribution, annulled with re-distribution and enhanced by the re-distribution of masses is provided. A new evidence updating strategy that is composed of a linear combination of the available evidence and the conditional evidence is also proposed. It enables one to account for the integrity’ and inertia’ of the available evidence and its flexibility’ to updating by appropriate selection of the linear combination weights. Several such strategies, including one that has a probabilistic interpretation, are also provided. 2003 Elsevier Inc. All rights reserved.
Open Access
Dempster–Shafer information filtering framework: Temporal and spatio-temporal evidence filtering
(IEEE, 2015-06-04) Weeraddana, D. M; Kulasekere, E. C; Walgama, K. S
This paper presents an information processing framework for distributed sensor networks. The framework is capable of directly processing temporally and spatially distributed multimodality sensor data to extract information buried in the noise clutter. Moreover, we introduce distributed algorithms to implement spatio-temporal filtering applications in grid sensor networks within the context of the framework. The proposed framework is based on the belief notions in Dempster-Shafer (DS) evidence theory and evidence filtering method. Further analysis is done by exploiting a fire propagation scenario when high noise is present in the sensed data. We compare intuitively appealing results against DS fusion method to grant further credence to the proposed framework.
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Dempster–Shafer information filtering framework: Temporal and spatio-temporal evidence filtering
(IEEE, 2015-06-04) Weeraddana, D. M; Kulasekere, E. C; Walgama, K. S
This paper presents an information processing framework for distributed sensor networks. The framework is capable of directly processing temporally and spatially distributed multimodality sensor data to extract information buried in the noise clutter. Moreover, we introduce distributed algorithms to implement spatio-temporal filtering applications in grid sensor networks within the context of the framework. The proposed framework is based on the belief notions in Dempster-Shafer (DS) evidence theory and evidence filtering method. Further analysis is done by exploiting a fire propagation scenario when high noise is present in the sensed data. We compare intuitively appealing results against DS fusion method to grant further credence to the proposed framework.
Open Access
Dempster-Shafer Information Filtering in Multi-Modality Wireless Sensor Networks
(publications.waset.org, 2013-07-27) Weeraddana, D. M; Walgama, K. S; Kulasekere, E. C
A framework to estimate the state of dynamically varying environment where data are generated from heterogeneous sources possessing partial knowledge about the environment is presented. This is entirely derived within Dempster-Shafer and Evidence Filtering frameworks. The belief about the current state is expressed as belief and plausibility functions. An addition to Single Input Single Output Evidence Filter, Multiple Input Single Output Evidence Filtering approach is introduced. Variety of applications such as situational estimation of an emergency environment can be developed within the framework successfully. Fire propagation scenario is used to justify the proposed framework, simulation results are presented.
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Developing online tutors and mentors in Sri Lanka through a community building model: Predictors of satisfaction
(IEEE, 2012-12-12) Gunawardena, C. N; Jayatilleke, B. G; Fernando, S; Kulasekere, E. C; Lamontagne, M. D; Ekanayake, M. B; Thaiyamuthu, T
This paper discusses the results of a tutor mentor development program that utilized a community building model to train online tutors and mentors in higher education institutions and professional organizations in Sri Lanka. Based on WisCom; an instructional design model for developing online wisdom communities, this tutor mentor development program which utilized a blended format of face-to-face and online activities in MOODLE, attempted to build a learning community between trainees, both academics and professionals who represented diverse disciplines and organizations. A regression model examined predictors of learner satisfaction, using four independent variables: Community Building, Interaction, Course Design, and Learner Support. Interaction emerged as a strong predictor of Learner Satisfaction explaining 50.2% of the variance in Learner Satisfaction. This finding shows the importance of designing interactive learning activities to support learning online, and contradicts the general belief that Sri Lankan participants would be less likely to interact online because they come from a traditional education system that encourages passivity and reception of ideas from a more learned teacher. Qualitative analysis showed evidence of several types of learning online as a result of collaborative group interaction, as well as issues that contributed to non-participation. Factors that motivated participants to stay engaged in learning could be classified into three categories: (1) general enjoyment, interest and motivation; (2) collaborative learning and community building; and (3) knowledge building. These results suggest that the online learning design based on WisCom led to learner satisfaction and supported interaction and collaborative learning in the Sri Lankan socio-cultural context.
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Distributed Wireless CSMA/CA based Unified Navigation Solution
(IEEE, 2006-12-15) Samarakoon, S. M. D. D; Silva, A. P. M; Samaraweera, S. M. D. W; Fernando, T. G. A; Kulasekere, E. C
This research proposes a multiple access protocol known as the Distributed Wireless CSMA/CA (DWCC). This protocol is optimized for a distributed wireless communication network where the node availability and behavior are both uncertain and unpredictable. An application based on a distributed communication network formed using inter vessels communication at deep sea is used to illustrate the salient features of the proposed protocol. A method is outlined on how the proposed new protocol can be applied to extend radar vision at each vessel in the presence of radar jamming and/or communication node failure at mid sea. That is, the DWCC protocol is used to gather information from all vessels to construct a cumulative radar map at any node and thus extending the radar vision beyond the display capability of a single node.
Open Access
An energy efficient distributed clustering algorithm for ad hoc deployed wireless sensor networks in building monitoring applications
(2009-01-01) Gamwarige, S; Kulasekere, E. C
In recent years Wireless Sensor Networks (WSNs) have been deployed for Building Monitoring (BM) as they provide a low cost and reconfigurable alternative to centralized cable based sensor systems. Using WSNs gives rise to unique issues in its practical usage. Lifetime of a WSN is one such crucial issue to be addressed during deployment. Clustering is an effective way of extending the lifetime of a WSN. In this article we propose a distributed and energy driven clustering algorithm where the selection of the cluster heads (CHs) are based on relative residual energy level of sensors. Furthermore, the CHs are rotated only when their energy drops below a dynamic threshold computed by the algorithm. As a result, the overheads in the inter sensor communications will be reduced and thereby the proposed algorithm will favor more powerful nodes over the weaker ones to prolong the lifetime of the entire WSN. This will effectively prolong the usability of the monitoring system and thus the underlying safety of the building. The results will show that the proposed algorithm performs better when compared to existing clustering algorithms. Further we present theoretical analysis of the performance of the proposed algorithm in terms of correctness and complexity and explain how to identify the optimal values for key parameters such as transmission range and re-clustering trigger threshold function value in order to maximize the network lifetime
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Energy expenditure of global reclustering and local delegation in Wireless Sensor Networks
(IEEE, 2010-09-06) De Silva, H. J; Gamwarige, S; Kulasekere, E. C
One of the most important aspects in a clustering algorithm in a wireless sensor network is the cluster head (CH) rotation mechanism. Global reclustering is the common and established method used for this purpose in many existing algorithms. This research proposes an analytical framework to investigate the average energy expenditure of the global reclustering method and a local delegation strategy in which the CH role is delegated to a member of the cluster without changing the initial cluster boundary. Further we investigate a strategy of partial local delegation within global reclustering rounds to achieve energy efficiency. Simulations are used to visualize the analytically derived results using the simulation environment MATLAB.
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Enhancing flexibility of belief representations
(IEEE, 2008-04-06) Senaratne, D; Kulasekere, E. C
Several attempts have been made to enhance the flexibility of belief representation in the Shafer model. This paper questions their ability to retain the intuitiveness. A method of enhancing the flexibility of belief representations, without compromising the intuitiveness is proposed. In it we relax the Shafer's exclusivity constraint by disregarding the formalism: 'subsets as propositions' and expressing support as functions of propositions. A compact and intuitive notation for propositions, termed N-of, is introduced. This notation simplifies the formulation of propositions from the statements humans make.
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An exhaustive search algorithm for checking limit cycle behavior of digital filters
(IEEE, 1996-10) Premaratne, K; Kulasekere, E. C; Bauer, P. H; Leclerc, L. J
The presence of limit cycles that may arise in fixed-point arithmetic implementation of a digital filter can significantly impair its performance. This paper presents an algorithm to determine the presence/absence of such limit cycles. For generality, the filter is taken to be in its state-space formulation. The algorithm is applicable independent of filter order, type of quantization nonlinearity, and whether the accumulator is single or double length. It may be utilized to construct limit cycle free regions in filter coefficient space. Once a filter is determined to be limit cycle free, a technique that provides a robustness region in coefficient space where all filters remain limit cycle free is also presented.
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Free route air traffic flow manager
(IEEE, 2005-12-11) Abeysooriya, M; Kulasekere, E. C
As the world moves towards the era of globalization and as the business world continues to revolutionize, meeting the expectations of a timely and safe air transportation system has become major challenge to the field of aviation. Most of the existing air traffic control systems primarily focus on generating pre-defined routes for aircrafts based on the 'fixed route model'. But with the advancement of technologies in the field of aviation an effective and practical mechanism called 'free route modeling' has been introduced. The few test beds that exist worldwide based on this concept, have been implemented for certain specific airspaces eliminating the possibility of using this strategy at any location worldwide. This paper presents the design and implementation of the 'free route air traffic flow manager' project which proposes a framework which can be used as a generic tool to over come this limitation. This tool will allow the user to dynamically create a free route modeling system for a certain airspace by configuring a 3D airspace according to the given requirements for that airspace. The dynamically developed free route modeling system will facilitate the functionalities of generating the initial free route for an aircraft & provide dynamic re- planning for the configured air space when a conflicting scenario is reported.
Open Access
IMAGE PROCESSING BASED GIRTH MONITORING AND RECORDING SYSTEM FOR RUBBER PLANTATIONS
(Academy & Industry Research Collaboration Center (AIRCC), 2015-02-01) Thilakarathne, C; Bhanusri, P; Randeny, T; Rupasinghe, H; Kulasekere, E. C
Measuring the girth and continuous monitoring of the increase in girth is one of the most important processes in rubber plantations since identification of girth deficiencies would enable planters to take corrective actions to ensure a good yield from the plantation. This research paper presents an image processing based girth measurement & recording system that can replace existing manual process in an efficient and economical manner. The system uses a digital image of the tree which uses the current number drawn on the tree to identify the tree number & its width. The image is threshold first & then filtered out using several filtering criterion to identify possible candidates for numbers. Identified blobs are then fed to the Tesseract OCR for number recognition. Threshold image is then filtered again with different criterion to segment out the black strip drawn on the tree which is then used to calculate the width of the tree using calibration parameters. Once the tree number is identified & width is calculated the girth the measured girth of the tree is stored in the data base under the identified tree number. The results obtained from the system indicated significant improvement in efficiency & economy for main plantations. As future developments we are proposing a standard commercial system for girth measurement using standardized 2D Bar Codes as tree identifiers
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Optimal placement of actuators and sensors for floor vibration control
(American Society of Civil Engineers, 2000-12) Hanagan, L. M; Kulasekere, E. C; Walgama, K. S; Premaratne, K
Lightweight floor systems are susceptible to excessive levels of vibration caused by occupant activities such as walking, dancing, and aerobics. Ongoing research utilizes active control to reduce vibration. Placement of multiple actuators and sensors for effective vibration control of flexible systems such as floors is a challenging task. The method proposed in this paper simultaneously determines optimal placements for multiple actuators, sensors, and appropriate output feedback gains of the controller. Instead of carrying out the controller design in the analog domain and then applying a transformation to arrive at a digital implementation, the proposed algorithm provides a digital controller directly. This allows lower sampling rates to be used at the implementation stage. To obtain faster settling times in the presence of external disturbances, a performance index that penalizes system states exponentially is utilized. The nonlinearities associated with actuator saturation due to force/stroke limitations is considered explicitly in the optimization. The proposed algorithm uses an interpolation scheme in case only partial knowledge of the mode shape is available. Hence it is applicable to a wider class of 2D structures that do not possess closed-form expressions for modal shapes and for which one has to resort to finite-element or experimental modal analysis.
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Optimization of cluster head rotation in energy constrained wireless sensor networks
(IEEE, 2007-07-02) Gamwarige, S; Kulasekere, E. C
The performance of energy driven cluster head (CH) rotation algorithms have been shown to be far more superior to time driven CH rotation algorithms when it comes to maximizing the sensor bed lifetime. The sensor bed life time is improved by selecting the proper points at which a CH role is relinquished to higher energy nodes via a CH rotation phase. However no formal analytical method is available to find the optimal point at which the CH rotation should be carried out. This research proposes an analytical iterative method to obtain the optimal points at which the CH rotation can be carried out. The method proposes an optimal value c opt for the energy threshold at which this rotation could occur. The values obtained via the analytical method is shown to be optimal via simulations using the EDCR and EDCR-MH algorithms. The analytical method proposed can be used in any energy driven algorithm to find the optimal point for CH rotations avoiding any ad hoc simulation based methods to maximize the lifetime of the sensor bed.