Browsing by Author "Perera, S"

Now showing 1 - 20 of 99

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: Thesis-Abstract
Accelerated complex event processing with graphics processing units
Rodrigo, PS; Bandara, HMND; Perera, S
As Big Data scenarios increasingly become common, a large number of distributed data processing systems require timely processing of high volumes of real-time data streams. Detecting complex correlations between incoming data streams in near real-time is at the heart of these data processing systems. Complex Event Processing (CEP) have been dominating in this domain since inception a decade back. But, growth of Big Data volumes demands for more performance and faster processing. CEP operators like stream join and event patterns require considerable processing power and have huge impact on the overall query processing performance. In some use cases these operators have to operate on lots of events simultaneously. Making parallel algorithms for these operators is a common approach for improving the individual operator performance. A Graphics Processing Unit (GPU) provides a vast number of parallel computing cores and leverage new parallel algorithms which enables novel problem solving approaches for existing problems. But the challenge is combining complex event processing and GPUs in the right way to get the maximum performance out of the this parallel hardware. There had been attempts to use parallel hardware in improving CEP performance in both commercial and academic implementations, and most of them uses multi-core approach. Only a very few researches had used GPUs for CEP. We believe the lack of GPU related CEP researches is that they are not designed to bene t from parallel processing in GPUs. In this research we investigate how and when GPUs can be used to improve the query processing performance of a popular open source CEP implementation, Siddhi CEP. Siddhi, by design, supports for parallel query processing in multi-core CPUs. This work propose a novel approach for parallel event processing in GPUs with several GPU event processing algorithms. Performance evaluation on our implemented algorithms shows, for a mix of complex queries, parallel event processing on GPUs achieve more than ten times event processing throughput than the sequential processing in CPUs. Moreover, our approach helped to reduce event queuing at the incoming event queue when there are high frequent input event stream and several complex queries.
item: Conference-Abstract
Accelerating complex event processing through GPUs
Rodrigo, PS; Bandara, HMND; Perera, S
Complex Event Processing (CEP) is a well-known technology in real-time Big Data processing systems. Performance of CEP engines is expected to scale with ever-increasing data rates and complex use cases. CEP operators like stream join and event patterns involve high computational complexity; hence, have a considerable impact on the overall query processing performance. Distributed event processing and CPU-level parallel event processing algorithms are common approaches for improving the performance. We explore how commodity massively parallel architectures like modern Graphics Processing Units (GPUs) can be utilized to improve the performance of frequently used CEP operators. We demonstrate how CEP operators such as event filter, event window, and stream join can be redesigned and implemented on GPUs to gain an order of magnitude improvement in throughput compared to a CPU-based mplementation. This work is demonstrated using NVIDIA CUDA based implementation of CEP operators for Siddhi CEP engine on low-end GPUs. Moreover, this approach reduces event queuing at the incoming event queue, even with a large number of event streams, high arrival rates, and several complex queries. Consequently, the average latency experienced by incoming events is also reduced.
item: Thesis-Full-text
Action research based case study on adopting IT for small and medium enterprises
(2017) Mallikarachchi, G; Perera, S
Sri Lanka is a major tea supplying country to the World tea market. The Tea Small Holdings (TSHs) sector is the main green leaf provider. However, for the past five years, the national tea production is in a declining trend. Recently, researchers have attributed this decline to lack of productivity, high production costs and labour shortage while poor business practices and poor knowledge on cultivation techniques are the main reasons for lack of productivity in TSH sector. In addition, there is a lag in distributing knowledge and support from Tea Small Holdings Development Authority (TSHDA) to TSHs. Information and Communication Technology (ICT) has been acknowledged in the agricultural sector in the form of information sharing networks for supply chain management and decision support software systems such as ‘precision agriculture’. Several studies have suggested to adopt ICT to tea industry for better coordination and for better information sharing. The Kenya Tea Development Agency (KTDA) considered information technology as a facilitator for competitiveness. However, there are inhibiting factors when adopting Information Technology (IT) to tea small holdings. This is an action research based case study that develops an IT system for a tea small holding in Sri Lanka, for its internal operations. The Design science research methods have been used for the development of the system. The adoption of the technology made use of the concept of IT therapy to overcome certain barriers such as lack of IT knowledge. The case study revealed a successful IT system for the internal operations of TSHs. Further research is needed to find the effects of the system on the productivity of TSHs. The adoption of IT could be facilitated by giving IT therapy. The study suggested to give free IT therapy to TSHs prior to the investment on adopting IT by a government or non-government agency.
item: Conference-Full-text
Adaptation of blockchain and smart contracts to the construction industry of developing countries
(Ceylon Institute of Builders - Sri Lanka, 2023-07-21) Anuradha, IGN; Ambagala, KK; Nanayakkara, S; Perera, S
The construction industry is often criticised due to its inherited challenges. Lack of trust and transparency, inadequate collaboration and complex structure have plagued the construction sector. Blockchain is a technology that has the potential to address these issues by automating procedures and enhancing traceability and transparency with its salient features. Whereas adaptation of blockchain within the construction industry is still at its inception. The situation is bleak in developing countries and there are numerous barriers and limitations that impact the implementation process. Therefore, this paper aimed to distinguish the barriers that affect the adaptation of blockchain and smart contracts for the construction industry of developing countries. The study used a mixed research approach. The barriers were ranked based on the data collected through a questionnaire survey and strategies to overcome them were identified through expert interviews. Findings derived from the analysis indicate that having a limited number of construction related software applications (powered by blockchain), the reluctance of the companies to bear additional costs to adapt blockchain and sluggish adaptation to new technologies as the significant barriers. As per the identified strategies, conducting an industry-wide digitalisation analysis, developing an industry-wide digitalisation strategy and recruiting skillful staff can be pointed out as the weighty strategies. The outcomes of this research were gained through the data collected from Sri Lanka, which is a limitation of this study. Eventually, a framework was developed as a guideline to implement blockchain and smart contracts for the construction industry of developing countries.
item: Conference-Full-text
Adapting general purpose platform-as-a- service for customized product deployment
(Department of Computer Science and Engineering, University of Moratuwa., 2014-09) Senanayake, DA; Perera, I; Meedeniya, D; Perera, S
The web services industry has evolved to a point where a lot of services are provided for free or a free tier of services is offered, most of the times. An attempt of trying to exploit this situation is to try and implement a game server based on completely free and open-source technologies or at least not exceeding the free tiers of commercial technologies.
item: Article-Full-text
AI-powered smart recycling: turning plastic trash into treasure
(University of Moratuwa, 2023) Kristombu, S; Thilakarathne, BS; Perera, S; Mendis, P; Ruwanpathirana, G; Rohanawansha, H; Wijesinghe, N; Mallikarachchi, C; Weerasinghe, P; Herath, S
In a world grappling with environmental challenges posed by plastic waste, innovative solutions are emerging to address the pressing issue of plastic recycling. Among these solutions, Smart AI-enabled automation and Upcycling stand out as promising technologies that offer the potential to revolutionize the way we handle and repurpose plastics. These technologies harness the power of artificial intelligence (AI) and automation to streamline the recycling process and transform discarded plastic materials into valuable products.
item: Conference-Abstract
Analysing the Effect of Curing Temperature on Micro-annuli Formation in Existing Wellbore Cement Sheath for Underground Hydrogen Storage
(Department of Earth Resources Engineering, 2023-08-28) Thirukumaran, A; Perera, S
Cement is used in a wellbore to isolate the formation fluids from the adjacent geologic regions. However, the interfaces between cement and casing as well as cement and formation can develop into leakage conduits in the form of micro-annuli. The formation of micro-annuli is a result of poor bonding which can be related to differential stress asserted on the wellbore system due to the changes in temperature and pressure. Micro-annuli are a type of cement sheath failure that can lead to significant leakage depending on the type of fluid and geometry of the micro-annuli. Studies over the years have assumed and simplified the pore geometry to be homogenous and uniform. In contrast, recent studies have revealed the complex nature of the geometry of the micro-annuli. In this experimental work, effort was made to visualise the initial cement bonding in three-dimensional space. X-ray CT scanning was carried out on cylindrical composite samples prepared with sandstone and API class G ordinary Portland wellbore cement. The images were reconstructed and analysed using AVIZO. The effect of different curing temperatures is illustrated through the quantification of micro-annuli and by analysing their geometry.
item: Article-Full-text
An Analysis of the Level of Knowledge on Prevention and Control of Breast Cancer among Female Undergraduates of University of Moratuwa
(2016-09-13) Perera, S; Seneviratne, SA; Seneviratne, TM
Breast Cancer is the most common form of cancer in Sri Lanka. Cancer is often curable if detected early. This study was conducted to investigate the level of knowledge of female undergraduates on prevention and control of breast cancer. Adopting the survey method, a semi- structured questionnaire was randomly distributed among 732 female undergraduates of three faculties of University of Moratuwa. Results revealed that the majority of the respondents have heard about breast cancer as well as some clinical features of breast cancer but their knowledge on risk factors of breast cancer and detection methods are not sufficient. They are aware about Breast Self-Examination (BSE) as a method of detection of breast cancer. However, majority do not know the technique of performing BSE. Their awareness about Well Woman Clinic is also low. Female undergraduates seek or encounter health related information through television, the Internet and newspapers as well as from medical officers. Majority do not believe the use of social media such as Facebook can be used to educate about breast cancers. Health education is vital in the university setup as undergraduates are future leaders. Regular awareness programmes to educate undergraduate about health aspects is the most preferred method.
item: Conference-Full-text
Annebot – an evolutionary artificial neural network framework.
(Computer Science & Engineering Society c/o Department of Computer Science and Engineering, University of Moratuwa., 2011-11) Mathotaarachchi, MSS; Perera, DC; Udawatte, L; Perera, S; Weerawardhana, S; Madusanka, A; Dilrukshi, T; Aravinda, H
A novel method for selecting the appropriate architecture and learning rule of an artificial neural network for a given application is discussed in this paper. Evolutionary Artificial Neural Networks (EANN) use the adaptation capabilities of genetic algorithms in which the natural selection process is used to attain the optimum network structure and learning algorithm for a specific task. ANNEbot is a framework which allows the combined powers of learning and adaptation of EANNs to be applied in various machine learning tasks. The framework was tested on the Iris Classification problem and the Wisconsin Breast Cancer Diagnosis problem, both of which provided results with above 90% accuracy. ANNEbot was also successfully applied on a robotic application for obstacle avoidance.
item: Conference-Full-text
Application based extension for windows network monitor widget
(Department of Computer Science and Engineering, University of Moratuwa., 2014-09) Kumarasinghe, CU; Perera, I; Meedeniya, D; Perera, S
This paper was written to give an idea about the windows network monitor extension which was developed in order to improve system security and application accountability of windows processes and to help the user to be aware of how much bandwidth is used by each process.
item: Conference-Full-text
AxiCo2 Concurrency coordination runtime on top of apache axis2
(Computer Science & Engineering Society c/o Department of Computer Science and Engineering, University of Moratuwa., 2011-11) Mudannayaka, S; Bandara, L; Gunawardena, V; Weerasooriya, C; Perera, S; Wimalawarne, K; De Silva, R; Weerawardhana, S; Madusanka, A; Dilrukshi, T; Aravinda, H
AxiCo2 is an Application Programming Interface (API) designed to simplify the implementation of concurrency in local environment as well as in the invocation of web services. AxiCo2 thereby reduces many inherent difficulties undergone by developers in programming multi-threaded applications. The higher level Application Programming Interface provided by AxiCo2 hides complexities associated with concurrency constructs and web service invocations. As a framework for concurrency and coordination among threads, AxiCo2 provides a means of asynchronous communication among threads which are used for local tasks and service invocations using “Ports” which are subdivided as Local and Service Ports. AxiCo2 has a thread pool within itself eliminating inherent overheads of thread per task approach. Apart from being a high level Application Programming Interface to hide complexities of concurrency, AxiCo2 provides means to the developer to configure applications to respond to partial success through the variety of Receivers provided. This set consists of Join, Choice, Multiple Item and Timeout Receivers which are used in implementing various logical constrains between tasks. AxiCo2 derives benefits both in programmability and performance perspectives.
item: Conference-Extended-Abstract
AxiCo2: concurrency coordination runtime on top of -e Axis2
(2011) Bandara, L; Mudannayaka, S; Gunawardena, V; Weerasooriya, C; Perera, S
AxiCo2 is an Application Programming Interface designed to simplify the implementation of concurrency in local environment as well as in the invocation of web services. AxiCo2 thereby reduces many inherent difficulties undergone by developers in programming multi-threaded applications. The higher level Application Programming Interface provided by AxiCo2 hides complexities associated with concurrency constructs and web service invocations. As a framework for concurrency and coordination among threads, AxiCo2 provides a means of asynchronous communication among threads using "Ports ". AxiCo2 has a thread pool within itself eliminating inherent overheads of thread per task approach. Apart from being a high level Application Programming Interface to hide complexities of concurrency, AxiCo2 provides means to the developer to configure applications to respond to partial success through the variety of Receivers provided. Our main focus in this paper is to present the underlying concepts of AxiCo2. -
item: Conference-Full-text
Biss a - a scalable and distributed tuple space
(Computer Science & Engineering Society c/o Department of Computer Science and Engineering, University of Moratuwa., 2010-09) Wickramarachchi, CD; Sumanasena, D; Fernando, PR; Wckramasinghe, US; Dias, G; Perera, S; Weerawarana, S; Gunasekara, C; Wijegunawardana, P; Pavalanathan, U
The idea of tuple spaces is based on the whiteboard design pattern & made its first appearance in the late 1980s. Tuple space provides content addressed associative shared memory abstraction for the processors accessing it. Tuple spaces can be used to time and space decoupled communication between the processes. In our work, we have implemented a distributed and scalable tuple space middleware infrastructure called BISSA that can be used for decoupled communication between applications. The BISSA application scope span from browser based applications to java applications. This capability is given by two major implementations; a distributed hash table (DHT) based peer to peer tuple space implementation and a web browser based tuple space implementation. In this paper we present and discuses our implementation methodology, test results and possible applications of the middleware.
item: Conference-Full-text
Blockchain as a project management platform
Hewavitharana, T; Nanayakkara, S; Perera, S
The construction industry will continue to be a key driver of economic growth for any country. It is one of the biggest industries in the world which contributes heavily to the economic development of a country. However, the productivity and the effectiveness of the industry have often been called into a question. Therefore, a number of different modelling tools and software have introduced to upgrade the standards of the construction industry. This review seeks to identify how blockchain can address the project management perspectives of the construction industry with respect to the guidelines mentioned in the Project Management Body of Knowledge. Five major criterions namely purchase management, contract management, asset and inventory management, finance management and subcontractor management were selected for the analysis using the PMBOK guidelines. For that, literature review using articles in ScienceDirect which appeared the context “blockchain in construction”, “blockchain and project management”, “application of blockchain” were referred. It is identified that the blockchain technology can assist financial management without involving third parties, subcontractor management by linking derivable and payment schemes, contract administration by using smart contracts, inventory and asset management by tracking and tracing material movements and purchase management by linking key stakeholders in supply chains.
item: Conference-Full-text
Brownfield redevelopment: a dual currency analysis of soil stabilisation methods
(Ceylon Institute of Builders, 2018-06) Brown, L; Perera, S; Rodrigo, MNN; Sandanayake, YG; Gunatilake, S; Waidyasekara, KGAS
Evidence of climate change, such as rising sea levels and higher average temperatures, has made society become increasingly carbon conscious in recent years. Therefore, carbon estimating is becoming prominent and this research explores methods of quantifying embodied carbon of different soil stabilisation methods. This research aims at evaluating the different methods of soil stabilisation for the remediation of previously developed, brownfield sites, using a dual currency approach of investigating both cost and carbon. Therefore, the effect of using different cementitious binders such as Pulverised Fuel Ash (PFA) and Ground Granulated Blastfurnace Slag (GGBS), in lieu of Ordinary Portland Cement (OPC) was investigated. Primary data, in the form of Bills of Quantities, was collected from a civil engineering contractor who has extensive experience in the land remediation sector in the UK. This enabled cost and carbon rates to be applied to the work items, to estimate in terms of cost and carbon inputs. This data was analysed using descriptive statistics to investigate if there is a correlation between cost and carbon inputs. The study revealed that to stabilise soil, soil matrix changes from one binder to another, whereas a higher content of GGBS and PFA to lime in the alternative methods than there is for OPC. In lieu of OPC and PFA, GGBS was identified as the most cost effective and lowest carbon emitting cementitious binder. However, though PFA also signified a carbon saving, PFA was comparatively costly. Further, a perfectly positive correlation lies between the mean elemental unit rates for costs and carbon.
item: Conference-Full-text
CARBON AND COST CRITICAL ELEMENTS OF OFFICE BUILDINGS: A CASE STUDY
(2016-08-24) Victoria, M; Perera, S; Davies, A; Fernando, N
Buildings emit two types of carbon (and greenhouse gases) namely Operational Carbon (OC) and Embodied Carbon (EC). Operational carbon is regulated in the UK as it contributed up to 70-80% of total emissions. On the other hand, EC started gaining attention with the rise of zero carbon buildings and due to the fact that the EC is unregulated at present. However, estimating EC is not completely standardised and there is room for improvement. EC can be controlled only by vigilant building designs. Studying building closely will provide better understanding of the carbon significant elements and enable designers to make informed decisions. Accordingly, a case study of an office building located in London in the UK is selected for the study. Capital cost (CC) and EC estimates were prepared using detailed cost plan of the building. Then, the building elements were classified as per NRM1 (New Rules of Measurement 1) element classification and the most carbon and cost significant elements were identified in the case study building. Not all of the identified carbon significant elements are identified as cost significant but Substructure, Frame and Services are identified as both carbon and cost critical elements while Stairs and Ramps, Internal Doors and Fittings, Furnishings and Equipment were identified to be the least carbon and cost significant elements. Findings of the case study building inform designers about the elements that has a vast reduction potential and worth investing their time on experimenting. However, the findings are based on single case study and, hence, cannot be generalised but to be seen as an exemplar for further research.
item: Conference-Full-text
Carbon and cost critical elements of office buildings: a case study
(Ceylon Institute of Builders, 2016-07) Victoria, M; Perera, S; Davies, A; Fernando, N; Sandanayake, YG; Karunasena, GI; Ramachandra, T
Buildings emit two types of carbon (and greenhouse gases) namely Operational Carbon (OC) and Embodied Carbon (EC). Operational carbon is regulated in the UK as it contributed up to 70-80% of total emissions. On the other hand, EC started gaining attention with the rise of zero carbon buildings and due to the fact that the EC is unregulated at present. However, estimating EC is not completely standardised and there is room for improvement. EC can be controlled only by vigilant building designs. Studying building closely will provide better understanding of the carbon significant elements and enable designers to make informed decisions. Accordingly, a case study of an office building located in London in the UK is selected for the study. Capital cost (CC) and EC estimates were prepared using detailed cost plan of the building. Then, the building elements were classified as per NRM1 (New Rules of Measurement 1) element classification and the most carbon and cost significant elements were identified in the case study building. Not all of the identified carbon significant elements are identified as cost significant but Substructure, Frame and Services are identified as both carbon and cost critical elements while Stairs and Ramps, Internal Doors and Fittings, Furnishings and Equipment were identified to be the least carbon and cost significant elements. Findings of the case study building inform designers about the elements that has a vast reduction potential and worth investing their time on experimenting. However, the findings are based on single case study and, hence, cannot be generalised but to be seen as an exemplar for further research.
item: Conference-Full-text
Carbon hotspots of office buildings in the UK
(Ceylon Institute of Builders, 2017-06) Victoria, M; Perera, S; Davies, A; Sandanayake, YG; Ramachandra, T; Gunatilake, S
Embodied carbon of buildings is receiving substantial attention due to the increasing statutory requirements on operational carbon of buildings. Even though the embodied carbon of buildings is not regulated at present there is a need to control embodied impacts of buildings because embodied carbon of buildings tends to increase as the operational carbon savings increase. Focusing on intensive emissions sources or the hotspots is an effective way of managing embodied carbon during the early stages of design though there is a gap with regards to the knowledge of carbon hotspots. Therefore, embodied carbon estimates of 28 office buildings in the UK were obtained and the carbon hotspots of buildings (in accordance with NRM element classification) were identified using the 80:20 Pareto Principle. Frame, Substructure, External walls, Services and Upper Floors were identified as carbon hotspots of the sample. However, findings do not support the 80:20 ratio in this case but propose a ratio of 80:36. In addition, the building elements were categorised into three types based on the probability of each element is being identified as a hotspot in the sample which is referred to as the ‘carbon hotspot probability’. The elements that were categorised as ‘Lead Positions’ and ‘Special Positions’ are the elements with higher reduction potential compared to remainder positions and require more attention during the early stages of design to achieve maximum reduction in embodied carbon.
item: Article-Abstract
Collaborative case-based estimating and design
Perera, S; Watsonb, I
Information Technology (IT) solutions to problems in construction design need to consider the perspectives of all the participants in the process; only then can IT provide a platform for integration. The research described examines issues involved in the integration of construction disciplines by using Case-Based Reasoning (CBR). It describes a hierarchical case memory structure and a context-based indexing method for retrieval and reuse of previous designs and their costs. Estimating and design cases selected for reuse are adapted with the use of sub-cases and domain specific adaptation rules. A prototype system, NIRMANI, was successfully implemented to support collaborative design.