Browsing by Author "de Silva, N"

Now showing 1 - 7 of 7

item: Thesis-Abstract
The Application of design innovation for increasing gem set jewellery exports in Sri Lanka
Samarasekara, KKGIC; de Silva, N
Application of'Design innovation' to increase gem set jewellery exports in Sri Lanka is the focus of this research. The vast discrepancy between country's resource capacity and its level of fabrication has inspired to conduct this research work. It was revealed during the study that the capability for further expansion of the jewellery industry lays mainly on Small and Medium Enterprises. Concurrently, lack of design innovation has been identified as a key constraint hindering the industrial competency and expansion. Thus, the approach of design innovation has been explored to maximize the gem set jewellery exports in Sri Lanka. The research methodology used was "mixed methods'. Multiple methods of data collection and analysis entailed to explore the research questions. The current circumstance of the Sri Lankan jewellery industiy in relation to the design led innovation was explored employing semi-structured, face-to-face interviews with a purposive sample. Data triangulation employed to increase the reliability and the validity. The triangulated data confirmed that most of the companies of leading and the medium categories successfully apply design innovation while the small sector lacks this approach in practice. It was revealed that the best approach to be succeeded through exports is the application of design innovation based on user centered design. It was suggested that inhouse design skill development, make available necessary information on user requirements and current global trends, international exposure can improve design innovation among the small sector. To attain the industrial goals, two major components need to be modified; the policy and the attitudes within the industry. In conclusion, approach of design innovation has been identified as the prominent avenue to develop the gem and jewellery industry in Sri Lanka.
item: Thesis-Full-text
Developing a model to predict unsafe behaviour of construction workers in Sri Lanka
Manjula, NHC; de Silva, N
The construction industry is known to be one of the most accident-prone of work sectors around the globe. Although the construction output is less in Sri Lanka, compared to developed countries in general, the magnitude of the accident rate in the construction industry is significantly high. Most of the occupational accidents happen due to the unsafe behaviour of the workers. Along with this revelation, behaviour based safety has emerged as an effective approach to ensure occupational safety. The principal step of behaviour based safety approach involves the identification of the unsafe behaviour of the workers. The research, therefore, focused on investigating factors influencing construction workers’ unsafe behaviour and developing a model to predict unsafe behaviour originated from those factors. Quantitative research strategy was selected to carry out the study considering the nature of this investigation. The acts characterising the unsafe behaviour of construction workers, and the factors influencing those were identified through a literature survey. A pilot study was undertaken to validate and generalise the literature findings to the Sri Lankan construction industry. Fifteen unsafe acts those characterise the unsafe behaviour and fourteen factors those influence the unsafe behaviour were identified relevant to the local context. A survey approach was used to collect data. C1 grade building construction organisations were selected as the sampling framework. Twenty organisations were chosen within Colombo district to gather information from construction workers. The processed data were used to develop and train an Artificial Neural Network (ANN) predictive model that could predict unsafe behaviour of a construction worker with respect to a score. Backpropagation architecture using Neuroph Studio software was employed to develop the predictive model. 277 data points taken from the survey were used to train the network. The architecture of the trained model was demonstrated by conducting a sensitivity analysis. Mean Absolute Error was the technique used in this process. Sensitivity analysis showed that the model is highly sensitive to the neuron corresponding to “education”, while the lowest sensitivity was evident for the neuron corresponding to “employee involvement in safety”. The results suggests that educational level of a worker has the highest influence on his unsafe behaviour at work. Similarly, the co-workers’ involvement in safety on site has the lowest influence on unsafe behaviour of a worker. Furthermore, the predictive model was validated for generalisability using seven data points those were not used in training the network. The findings depict that the performance of the model is accurate due to high generalisation capabilities in the validation session. The model serve as a prototype tool to determine the unsafe behaviour level of construction workers and their safety training needs. This model can further be employed as a tool to proactively design interventions to avoid or minimise occupational accidents based on the unsafe behaviour levels of construction workers.
item: Conference-Full-text
Effect of a shear key on the behaviour and stability of cantilever type retaining walls
(IEEE, 2022-07) Arulananthan, G; de Silva, N; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Retaining walls are categorized into several types, out of which cantilever retaining walls are the commonly used retaining wall type. Shear keys are the structures incorporated in the cantilever retaining walls to increase their resistance to sliding. The current study investigates the optimal location and depth of the shear key. A theoretical approach based on limit equilibrium and numerical modelling were adopted in the analysis. Limit equilibrium analysis was carried out using the Excel spreadsheet application. The values of Factor of Safety against sliding and overturning, varying with the shear key’s depth and location, are presented as graphical representations. Finite Element Analysis was carried out using PLAXIS 2D software to analyze the variation of the overall stability with the increasing depth of the shear key. The limit equilibrium analysis observed that utilizing a shear key enhances the stability of the retaining wall against sliding. It was also found that the increase in the depth of the shear key reduces the stability of the retaining wall against overturning, and the optimum location of the shear key is at the heel of the wall base. Results from the Finite Element Analysis showed that the retaining wall’s overall stability increases with the increase in the depth of the shear key.
item: Conference-Full-text
Effect of Starch Particle Size Reduction on the Performance of Sized Warp Yarns
(2015-08-03) Fernando, EASK; Paranavithana, T; Dissanayaka, U; Premarathna, W; Atambawa, A; de Silva, N; Tissera, N
The mechanical and physical properties of tapioca based starch are known to vary in relation to physical parameters including the particle size of the starch granules. In this study, ultra sonication was used to reduce the particle size of starch solution from 100μm to 8μm and the modified starch was applied on poly cotton warp yarns. The strength, extension, moisture regain and size add-on% was tested and compared with the properties of conventionally sized yarns. The results showed that better strength and extension properties can be obtained by the application of ultra sonicated size solution at lower drying temperatures and lower squeeze roller pressures with minimum size add-on%.
item: Thesis-Abstract
Effective management of utility condominiums
(2014-12-12) Palpita, VPKNJ; de Silva, N
Effective Management of Utility Condominiums Condominiums have become new phenomenon in Sri Lanka. Because of the recent devastation and destruction caused by Tsunami in 2004, the need for housing has become critical and urgent. Further the government program of condominiums to relocate of 55,000 squatters under these circumstances has been the best and the most practical solution Condominium apartments. The condominium property Act No. 12 of 1970 was the first legislation enacted for condominium properties in Sri lanka. The law regarding maintenance, management and administration of common amenities is contained in the Common Amenities Board Law (Act No. 10 of 1973). The Law, relating to condominiums is contained in the apartment of ownership Law No. 11 of 1973 as amended by Act No. 45 of 1982, Act No.4 of 1999, Act No. 27 of 2002 and Act No.39 of 2003. The recent law regarding condominium contained in Act No 39 of 2003 has given greater powers to the management corporation and its authorities as a legal body. Through this study, it was aimed to identify the nature of the current management process of management corporations and the process established by the condominium management authority (CMA). A questionnaire survey was used with Stake holders, community members and MC’s officials to assess the implementation of current condominium management process and CAB role of condominium management process and find out the most significant factors for non implementation of the current management system of utility condominiums and develop guideline to address them. However it was identified that there are many deficiencies in management process of utility condominiums of low income group families. This was due to several reasons related to their level of education, financial capabilities, capacity, priorities of the people, and interaction between CMA and Local Authorities. Thus the main objective of this research study was to develop an efficient management policy for utility condominiums. The study revealed that identified all 9 deficiencies were significant in utility condominium management process.
item: Conference-Full-text
Evaluation of soil liquefaction in Sri Lanka - a dynamic approach using geotechnical investigation data
(Department of Civil Engineering, University of Moratuwa, Sri Lanka., 2012-12) Kumarasiri, C; de Silva, N; Abayakoon, S; Nawagamuwa, U; De Silva, LIN
Soil Liquefaction is a process, where granular soils below the ground water table temporary lose its strength and behaved as a viscous fluid rather than a solid. The porewater pressure is suddenly increased during an earthquake due to the cyclic loading. The increased porewater pressure is forced the soil particles to suspend in water. As a result, the buildings, utility services, natural substances and other structures are collapsed causing severe damage to the people and the nature. In Sri Lanka, it is rare to find the historical data of liquefaction or related incidents. Recent studies demonstrated that there is a potential for liquefaction in some places of the island. It could be evaluated by using the basic geotechnical investigation data, according to the simplified procedure proposed by Seed and Idriss (1971). This paper is intended to evaluate the liquefaction potential in Sri Lanka by identifying the liquefiable layer thickness, using an extensive geotechnical investigation data base. As per the analysis 384 locations were identified as susceptible for liquefaction with various layer thicknesses out of 3282 locations analysed. Further, the analysis has extended for varied ground water table.
item: Thesis-Abstract
Time based pricing model for distribution utilities in Sri Lanka
(2015-06-26) Wijesinghe, WNU; Perera, HYR; de Silva, N
Cost causation based allocation of infrastructure cost is a quite difficult thing in distribution networks. Thus in practice, majority of distribution tariffs in the world price electricity through traditional averaging. This is because of the difficulties in implementation of advanced pricing strategies mainly complexity, caused by high density of nodes compared to transmission networks and lack of advanced metering infrastructure. This thesis analyzes the question of allocating infrastructure of fixed cost, leading to a more absolute solution. It proposes a time based pricing model (TBPM) which can be easily adopted in distribution networks and transmission networks. Further this study also includes the recovery of cost of losses which is more in line with proposed costing of infrastructure. The proposed TBPM is cost causation based and suitable for distribution networks. TBPM recovers the costs by allocating to either active energy or both active and orreactive energies. It works out a price in a particular time interval basis such ashourly basis etc. It comprises of two components • A time based pricing per energy to allocate fixed cost which is derived from incremental fixed cost per energy unit. • Allocation of cost of losses pertaining to the network at the time of delivery per energy. Requirements for TBPM are simple and straightforward such that it can be easily implemented in distribution networks like in Sri Lanka. A TBPM calculation was done for an 11 kV network spread over 37 km2 for its actual load patterns. The results verify the cost reflectivity of TBPM by recovering of cost as per the exact burden. The strategy can also be applied to transmission networks.