Browsing by Author "Rajapaksha, D"

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    item: Conference-Abstract
    Advanced structural health monitoring system for bridges in Sri Lanka
    (Department of Civil Engineering, University of Moratuwa, Sri Lanka., 2021-11) Rajapaksha, D; Lewangamage, CS; Vishnu, P; Hettiarachchi, P
    Bridges are a critical component of the transportation infrastructure system because a failure in a particular bridge may affect a wide range of areas adversely. Also, the intensity and frequency of natural shocks and stresses that can affect the performance of the bridges, such as earthquakes, floods, and tsunami have rapidly increased during the past few years, which increases the vulnerability of bridges by combining with aging. Hence it is crucial to monitor the current health of bridges so that devastating failures could be avoided by following a structured maintenance program. In that case, advanced Structural Health Monitoring (SHM) systems that are rapidly developing for past decades with the development of IoT, have been used for bridge monitoring purposes in other countries. However, the condition of the bridge monitoring system is not so developed in Sri Lanka yet. Also, the commonly used methods such as visual inspection and traditional tethered methods are incorporated with some drawbacks. Therefore, the requirement for an advanced SHM system for bridge monitoring in Sri Lanka has been raised. In this study, a low-cost wireless synchronous sensor network developed by the Department of Civil Engineering, University of Moratuwa was applied and monitored on a bridge as a pioneering step of implementing an advanced online SHM system for bridges in Sri Lanka. Here, the synchronous vibration time history of the structure was measured using the sensor network with high accuracy. After a filtration process, the data was applied for calculating the experimental modal parameters such as natural frequencies and mode shapes using Fast Fourier Transformation (FFT) and peak picking method. Finally, the experimental results were compared with the results of Finite Element Analysis (FEA) through the Modal Assurance Criteria (MAC). The MAC analysis showed values greater than 0.84 for the first four modes shapes which indicates a good correlation with the experimental results and the FEA results. Furthermore, the measured acceleration data was used to assess the serviceability state of the bridge as well.
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    item: Thesis-Abstract
    A Study on the value of motivation strategies and practices for the productivity improvement in the Sri Lankan software industry
    Jayawardena, KKS; Rajapaksha, D; Gamage, C
    The software industry is unique in that it is a highly knowledge intensive industry. Improving the productivity of knowledge workers is one of the major challenges for the present day software development business world. The motivation of workers in software industry is considered to be the factor having the largest impact on productivity of software engineers and continues to be undermined by many of the processes and methodologies in software industry. The management often assumes that all their employees are motivated by the same things, but in reality it is more likely that employees are motivated by a whole range of factors. If the management does not know what motivates their employees to turn up for work every day, how can they expect their workers to perform well? The purpose of this research is to study the value of motivation strategies and practices for the productivity improvement in the Sri Lankan software industry. For this purpose three surveys were used in this empirical research study. In the first stage of this research, the most critical motivation strategies and practices used in the Sri Lankan software industry were determined through a survey questionnaire. This data gathering survey also identified the various methods under each motivational strategy with the prioritizations of their usage. The second survey questionnaire was developed on the basis of the first survey observations and it was invented to measure the perceptions the respondent workers have on motivation strategies, practices, line management activities and employee productivity. The final survey was used to get the perception of management on employee productivity to further validate the research results. The survey results highlighted the fact that fair wages was the top ranked motivating factor and the financial impact of the productivity was the main focusing area of the employees’ productivity in the industry. Further more the research results revealed that there is a strong positive relationship between motivation strategies and the employee productivity and there is a positive relationship between line management activities and the employee productivity. The research strongly emphasized that there are several areas to be improved for the line management activities and the employees’ productivity.It is expected that the research results would be a significant contributution to further emphasize the value of motivation strategies and pracrices for the productivity improvement of employees in the Sri Lankan software industry.