Faculty of Engineering
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Publication Embargo Investigation of the Carrying Capacity of the Socketed Region of Bored and Cast-in-Situ Piles in Sri Lanka(ASTM International, 2018-06-07) Thilakasiri, S; Rathnayaka, AApproximately 90 % of Sri Lanka is underlain by Proterozoic gneisses consisting of Precambrian basement, with Phanerozoic sediments being restricted to the coastal areas. Due to the availability of bedrock on an average at approximately 20 m below the ground surface, end-bearing bored and cast-in-situ piles socketed into bedrock are very often used in Sri Lanka to support large structures such as high-rise buildings. However, significantly high variations of both the bedrock profile and properties are observed even within small sites. Therefore, termination of the piles within the bedrock is a very important consideration during the installation of piles to achieve the required capacity. Pile termination is generally done using the drilling rate and observing the rock cutting as the criteria for terminating piles. The relationship between the drilling rate, the quality of the rocks, and mobilized skin friction within the rock socket are investigated in this paper based on the results of instrumented pile load tests. The results of the analysis indicate that the mobilized skin friction in the rock socket does not have a direct correlation with the drilling rate but on the overall quality of the bedrock. Due to the low cost and quick execution, engineers use the skin friction distribution and end-bearing capacity obtained from signal matching of high-strain dynamic load test results for the design of piles. In this paper, mobilized pile capacities within the rock socket are investigated using measured field-instrumented maintain load test results and the results from signal matching. The results of the analysis indicate that the static load-settlement curve can be obtained from CAPWAPVR analysis, but the mobilized skin friction distribution and the end bearing cannot be accurately obtained from an acceptable CAPWAP signal matching.Publication Embargo A Semi Distributed Approach for Feasible Min-Max Fair Agent-assignment Problem with Privacy Guarantees(IEEE, 2018-03) Weeraddana, P. C; Fischione, C; Xu, Y; Alfonsetti, EIn cyberphysical systems, a relevant problem is assigning agents to slots by distributed decisions capable of preserving an agent's privacy. For example, in future intelligent transportation systems, city-level coordinators may optimally assign cars (the agents) to parking slots depending on the cars' distance to final destinations in order to ensure social fairness and without disclosing or even using the car's destination information. Unfortunately, these assignment problems are combinatorial, whereas traditional solvers are exponentially complex, are not scalable, and do not ensure privacy of the agents' intended destinations. Moreover, no emphasis is placed to optimize the agents' social benefit. In this paper, the aggregate social benefit of the agents is considered by an agent-slot assignment optimization problem whose objective function is the fairness among the agents. Due to the problem's complexity, the problem is solved by an approximate approach based on Lagrange duality theory that enables the development of an iterative semidistributed algorithm. It is shown that the proposed algorithm is gracefully scalable compared to centralized methods, and that it preserves privacy in the sense that an eavesdropper will not be able to discover the destination of any agent during the algorithm iterations. Numerical results illustrate the performance and tradeoff of the proposed algorithm compared to the ideal optimal assignment and a greedy method.Publication Embargo An Overview of Social Engineering in the Context of Information Security(IEEE, 2019-01-31) Kaushalya, T; Randeniya, R. M. R. S. B; Liyanage, SSocial engineering in the context of information security is the exploitation of human psychology to gain access into secure data. Human emotion can act as both a strength and a weakness. When it comes to the world booming with technology, human emotions which are completely unrelated to the matter is made to relate through social engineering. Social engineering employs `traps' to pry on human emotion and its vulnerability, taking advantage of the flaws of human psychology. Information security breaches utilising social engineering techniques are vast, so that social engineering in this context is a topic which could not be neglected. This research paper presents an overview of social engineering attacks and suggested defence mechanisms. An introduction to social engineering attacks are given, with context to the current trends and related vulnerabilities. Main reasons for the spread of social engineering attacks in the current context are also presented. Attack frameworks are presented and defence approaches are proposed at the end.Publication Embargo Management of municipal solid waste open dumps immediately after the collapse: An integrated approach from Meethotamulla open dump, Sri Lanka(Elsevier, 2019-07) Jayaweera, M; Gunawardana, B; Gunawardana, M; Karunawardena, A; Premasiri, S; Manatunge, J; Wijeratne, N; Thilakasiri, S; Karunarathne, D; Dias, VMeethotamulla open dump (MOD) of Sri Lanka that has received about 290,000 metric tons of mixed MSW annually collapsed on 14th April 2017 with massive devastation. An integrated approach was attempted to control further collapse with the deployment of drone-assisted and stand-alone instrumentation. The collapsed dump was analyzed for attributes, including contours, heights, wetness, temperature levels, tension cracks, landfill gases, fire, explosion, and asphyxiation hazards with 24-h surveillance after one day of the collapse. The mode of MOD failure was implicated to be deep-seated (rotational) slope failure. A short-term plan, consisting of 12 activities was prepared and successfully implemented. The activities of the short-term plan were carried out at the dumpsite until the water level fluctuations <5 cm, inundation of the toe area receded completely, the horizontal displacement of surface markers <20 mm, lower explosive levels of CH4 and CO less than 5 and 12%, respectively, O2 level improved up to 21%, and temperature variation of the collapsed face <2 C. The short-term plan was halted when the factor of safety for slope failure of the critical face improved from 0.807 to 1.286 ensuring no signs of a subsequent collapse of the MOD. An early warning system was established in the case of an imminent collapse. This integrated approach, to our knowledge, is the first study instituted, and this holistic management effort could be easily replicated to avoid disasters from slope failures of landfills or open dumps that may occur elsewhere.Publication Embargo Management of municipal solid waste open dumps immediately after the collapse: An integrated approach from Meethotamulla open dump, Sri Lanka(Elsevier, 2019-07-15) Jayaweera, M; Gunawardana, B; Gunawardana, M; Karunawardena, A; Dias, V; Thilakasiri, S; Karunarathne, D; Wijeratne, N; Manatunge, J; Dissanayake, J. MMeethotamulla open dump (MOD) of Sri Lanka that has received about 290,000 metric tons of mixed MSW annually collapsed on 14th April 2017 with massive devastation. An integrated approach was attempted to control further collapse with the deployment of drone-assisted and stand-alone instrumentation. The collapsed dump was analyzed for attributes, including contours, heights, wetness, temperature levels, tension cracks, landfill gases, fire, explosion, and asphyxiation hazards with 24-h surveillance after one day of the collapse. The mode of MOD failure was implicated to be deep-seated (rotational) slope failure. A short-term plan, consisting of 12 activities was prepared and successfully implemented. The activities of the short-term plan were carried out at the dumpsite until the water level fluctuations <5 cm, inundation of the toe area receded completely, the horizontal displacement of surface markers <20 mm, lower explosive levels of CH4 and CO less than 5 and 12%, respectively, O2 level improved up to 21%, and temperature variation of the collapsed face <2 °C. The short-term plan was halted when the factor of safety for slope failure of the critical face improved from 0.807 to 1.286 ensuring no signs of a subsequent collapse of the MOD. An early warning system was established in the case of an imminent collapse. This integrated approach, to our knowledge, is the first study instituted, and this holistic management effort could be easily replicated to avoid disasters from slope failures of landfills or open dumps that may occur elsewhere.Publication Embargo Prototype of Radio Frequency Identification Technology Utilization for Monitoring of BTS Room Using of IoT (Internet of Things) System(IEEE, 2019-11-28) Saragih, Y; Kurnia, F. E; Aji, S; Elisabet, A; Roostiani, H. A; Hafeel, A. AThe level of battery theft in the BTS room often occurs. RFID prototype is used to open the BTS room is replacing the conventional key. To improve the BTS room security system, a vibrating sensor is used which is applied to the BTS room door, if anyone wants to break or damage the BTS room door by force then the alarm sounds, and use an ultrasonic sensor to detect whether there is a person or object in front of the BTS room, if a person or object is blocking in front of the BTS shelter ≤100 cm, the alarm will sound continuously. Also, the BTS shelter can be monitored via a smartphone as well as getting notifications both in email, smartphone and in the Blynk application.Publication Embargo Digital Creation of Color Illusion Fabricated by Overlaying Different Colored Translucent Textiles Using Images(IEEE, 2019-12-18) Wijesinghe, A; Seneviratne, L; Abeyratne, SOverlaying different colored textiles which are translucent is a straight forward task to complete physically, in contrast this task is difficult to achieve digitally. Amount of information obtained from an image is limited, which is a major difficulty faced when using images to identify the features of a textile such as color, material, texture, thickness and transparency. An algorithmic approach is taken based on three hypotheses; random superimposing, background replacement and color augmentation. These techniques are based on; color identification, background replacement, random selection, pixel superimposing, color blending and image color augmenting. The algorithms are researched, implemented, experimented in-depth and critically compared. Four algorithms are implemented, two based on randomly superimposing and one each based on background replacement and color augmentation. Background replacement algorithm was hardly able to complete the task effectively, thus is the lowest ranked algorithm. In contrast, randomly superimposing and color augmenting algorithms were capable of carrying out the task successfully. Randomly superimposing costed the least time to complete, but the generated images were unnatural whereas color augmenting produced a perfectly natural image though the color of the final output was inaccurate. Further refining the color prediction algorithm is proposed to develop a more effective system.Publication Embargo A Comparison of Fuzzy Logic Controller and PID Controller for Differential Drive Wall-Following Mobile Robot(IEEE, 2019-12-18) Ratnayake, R. M. N. B; De Silva, S; Rodrigo, C. JThis paper presents a comparison between PID controller and Fuzzy rule based controller of a differentially steered wall following mobile robot. Four different maps, generated using Mapper3 software are used to simulate the robot in MobileSim platform. The code was implemented using C++ language in ARIA development package. The robot simulation is performed with Pioneer P3-DX robot. In this study, the data was collected for each cases such as: left wall following and right wall following. In order to validate the results, maximum of 40 runs were conducted for each map and the results were compared with the illustrated methods.Publication Open Access Effective Sizing of Natural Systems for Grey Water Treatment Using Locally Derived Parameters(Spriger Link, 2019-08-07) Karunarathne, SWhen properly managed, grey water can be a valuable resource, which agricultural and horticultural practitioners as well as home gardeners can benefit from using to provide an excellent nutrient sources for vegetation. Natural treatment systems such as constructed wetlands emphasizing on sustainability and wastewater reuse typically for agricultural irrigation/home gardening can be considered as an ideal alternative to close the loop in terms of nutrient capture and water conservation. This paper presents a part of an analysis done to estimate the locally derived treatment wetland parameters based on BOD5 removal mechanisms of a pilot scale subsurface horizontal flow constructed wetland (SSHF CW) treating greywater. A pilot scale SSHF CW with a surface area of 8.64 m2 and a substrate depth (with 20 mm aggregates) of 0.7 m was monitored. This is a part of a long term study carried out to test the viability of SSHFCW for treating grey water for agricultural reuse. The wastewater flow measurements were taken from the inlet and the outlet of the constructed wetland while monitoring the hydraulic (HRT) and organic loading rates. Water samples from four sampling points were collected on a long term basis. Equations based on a kinetic model of a first-order piston flow reactor was used to calculate the relationship among the design parameters appropriate for local conditions. The HRT varied from 3.3 to 4.7 d for maximum and minimum inflow loading rates observed. Using the data from the current study, a resizing exercise for a subsurface horizontal flow constructed wetland was carried out. Accordingly, a household with four people, discharging 720 L/d greywater with an average influent BOD5 of 300 mg/L could be treated up a BOD5 concentration of 25 mg/L using an area of 3.60 m2 of SSHF CW, implying only 0.975 m2 of per capita land usage.Publication Embargo Robotic gripper design to handle an arbitrarily shaped object by emulating human finger motion(IEEE, 2015-08-24) Welhenge, A. M; Wijesinghe, R. D; Rajakaruna, R. M. T. PControlling a robotic gripper to handle objects in different sizes and shapes in real-time is a complex task. The challenge is to adapt and position the gripper according to a target object. In this work, by considering a three fingered robotic gripper with a finger structure similar to that of human finger, we study the positioning of fingers in a gripper in the two dimensional plane. Using an inverse kinematic model for a pulley based underactuated mechanical finger, we derive a region of reach in the plane of the finger. Simulations demonstrate the limits of reach under different conditions. This can be used to derive the positioning of each finger, as well as in path planning to control the reach of the gripper.