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Item Detecting and preventing plagiarism in online assessment(University of Kelaniya, 2008) Wannige, C.T.; Sonnadara, D.U.J.; Usoof, H.A.; Hewagamage, K.P.Assessment is an important area in both teaching and learning. E-assessment is the foremost methodology for assessment in distance learning. This paper presents a method based on client-server architecture that can be used in capturing/preventing plagiarism in online assessments for distance learning centres. Among many possible scenarios of plagiarism, developed system focused on preventing or capturing unauthorised help obtained from online chat forms, websites or other types of communication mediums as well as use of stored text/restricted software. Bench tests show high degree of accuracy in capturing plagiarism scenarios by monitoring the change of grey values observed in edge detected screen shots. During pilot tests, participants attempted activities of plagiarism although the software was designed to prevent the act of plagiarism. The results show 97% accuracy in capturing plagiarism scenarios by the developed software in a restricted Ubuntu Linux environment.Item Mathematical structures in pattern organizations(University of Kelaniya, 2008) Kodituwakku, S.R.Since the introduction of design patterns, a large number of patterns have been identified and documented. As a result, patterns in the literature relate one another in different ways. Unfortunately, most of these patterns are not properly organized. In applying these patterns in to problems at hand novice designers encounter many difficulties such as identification and selection of collectively applicable set of patterns that suits the problem at hand. We investigate mathematical structures in existing pattern organization techniques such as pattern catalogues, pattern systems and pattern languages. Then we attempted to use these mathematical structures in developing a new organization technique. This paper proposes a new organization method and illustrates it with a collection of object oriented patterns drawn from the literature. Our investigation indicated that existing pattern organizations form graph structures and categorical structures. These structures are formed by patterns and relationships among them. The proposed organization method organizes patterns into sequences according to the relationships among patterns. This organization consists of two types of categories: major category and alternative category. The major categories are defined based on the Uses relationship and the alternative categories are defined based on the Variants, Refines and Conflicts relationships. Each major category consists of patterns that have potential to form a pattern system or a pattern language. So they assist practitioners in finding a sequence of related patterns that can be collectively applied to solve complex problems. Each alternative category consists of patterns that provide alternative solutions to the same problem or similar problems. It assists in finding a number of possible solutions (patterns) to a particular problem. The proposed organization combines these two types of categories by structuring them into pattern sequences. A pattern sequence consists of a major category and a collection of related alternative categories. Pattern sequences assist practitioners in finding a collectively applicable patterns and possible alternatives to them. So pattern sequences facilitate the selection of most appropriate sequences of patterns to solve complex problems without searching through the pattern literature.Item Sago as a medium for “in vitro” culture of some common soil bacteria(University of Kelaniya, 2008) Kapilan, R.; Thavaranjit, A.C.Nutrient agar (NA) medium is universally used as a general purpose medium for the culture of a broad range of bacteria and the cost of this commercially available medium is considerably high. Sago (Metraxylon sagu) contains a considerable amount of starch and a small amount of reducing sugars and is not used as a staple food in Sri Lanka. This study was aimed to find out the suitable composition of the sago medium compared with NA and to carry out growth studies of soil bacteria on sago medium. Media were prepared in different compositions by addition of different amount of sago in 100mL volume (25mL of distilled water + 75mL of young king coconut sap) separately. Bacterial suspensions (5.21×106 cfu/ml, SD=1.12) of Bacillus, Pseudomonas, Klebsiella, Enterobacter, Serratia and Staphylococcus were transferred on the selected sago medium separately by using spread plate techniques. There was no significant difference between sago and NA media in number of the colonies (t test; p = 0.05). Colonies appeared earlier in NA media than in sago media. But the colony morphological characters such as shape/form, margin, elevation, colour and size were almost similar to all bacteria selected on both media, except consistency. Thus, instead of NA the low cost and easily available sago medium could be recommended for the cultivation of soil bacteria.Item Applied magnetic field and stress induced anisotropy dependence of energy for oriented ferromagnetic thick films(University of Kelaniya, 2008) Samarasekara, P.The energy of perfectly oriented thick ferromagnetic films at different applied magnetic field and stress was studied using classical model of Heisenberg Hamiltonian. For the values of parameters used in this report, the energy required to orient the film with 1000 layers in 41.4° or 57.6° directions becomes minimum at applied magnetic fields of ω Hout = 4.8 or ω Hin = 4.8, respectively. The film can be easily oriented in 172° direction by applying the external stress ω Ks = 3.6 perpendicular to the film plane, for the values of parameters used in this report. These final results mainly depend on the values of other parameters used for calculations. The energy becomes minimum and maximum at almost the same values of oriented angle (θ), in plane magnetic field, out of plane magnetic field and stress for both sc(001) and bcc(001 lattice types. But the values of energies corresponding to maxima and minima are slightly different for the sc(001) and bcc(001) lattices.Item Investigation of anisotropy constants dependence of ultra-thin ferromagnetic films with second order perturbed Heisenberg Hamiltonian(University of Kelaniya, 2007) Samarasekara, P.The variation of energy of ferromagnetic ultra-thin films with second and fourth order anisotropy was investigated using Heisenberg Hamiltonian with second order perturbation. The study was limited to sc(001) film with three layers. Graphs indicate energy minimums at certain values of second order anisotropy, fourth order anisotropy and angle. Films with fourth order anisotropy ω )4( Dm =4 can be easily oriented in the direction given by angle of 2.66 radians for the values of other energy terms used in this simulation. When the second order anisotropy ( ω )2( Dm ) is 3.1, preferred direction is 0.754 radians. When the second order anisotropy varies at a constant value of fourth order anisotropy, the graph indicates more energy minimums.Item Studies on antioxidant activity of Indian gooseberry fruit and seed(University of Kelaniya, 2007) Nadheesha, M.K.F.; Bamunuarachchi, A.; Edirisinghe, E.M.R.K.B.M.; Weerasinghe, W.M.S.K.Fruits and seeds of Indian Gooseberry (Phylanthus emblica, S. Nelli) were investigated to evaluate their antioxidant activity. Antioxidant activity was evaluated by the estimation of peroxide values (PV) of shark liver oil, treated with fruit and seed extracts incubated at 600 C for a period of nine days. Seed extracts showed higher antioxidant activity than fruit extracts. The ethanol and ethyl acetate extracts of the fruit and all extracts of the seed were found to have higher antioxidant activity than the synthetic antioxidant butylated hydroxy toluene (BHT).Item Serum levels of some biochemical constituents of captive Sri Lankan elephants (Elephas maximus maximus)(University of Kelaniya, 2005) de Alwis, G.K.H.; Wijesekara, R.D.; Vithana, D.; Neththasinghe, N.; Ratnasooriya, W.D.Item Comparison between ultrasonic acoustic emission (UAE) and hydraulically measured loss of hydroulic conductance in Eucalyptus spp. clone GU210(University of Kelaniya, 2005) Manoharan, P.; Pammenter, N.W.Item Oxygen partial pressure dependence of the coercivity of sputtered Polycrystalline nickel ferrite films(University of Kelaniya, 2005) Samarasekara, P.Item Growth characteristics of two selected Eucalyptus clones in relation to physiological responses(University of Kelaniya, 2005) Manoharan, P.; Pammenter, N.W.