International Research Symposium on Pure and Applied Sciences (IRSPAS)
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Item Impact of teamwork quality on software development project success: Sri Lankan context(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Kumari, P.D.R.S.; Wijayanayake, W.M.J.I.Software has become a very crucial in all facets of modern world by the growth of technology. A software development project (SDP) can be viewed as a set of activities performed by a set of developers. Software development is a complex activity that requires teamwork effectively. Teamwork is a dynamic process of working collaboratively with a group of people in order to achieve a goal. According to the literature, Software project success can be measured using four indicators namely, cost, quality, time and scope and there is a significant relationship between teamwork quality (TWQ) and SDPs success. Most of researchers have done their research works on teamwork for German and Dutch SDPs. However we cannot apply these findings direct to Sri Lankan context. As found literature of social and cultural factors can be effect to performance of software development project. The main objective of this research is to come up with a framework to explain impact of TWQ for SDPs success. To achieve that objective, conceptual model was developed as mention in the figure. The model was derived from different models which are found in literature. Then the indicators which are used to measure TWQ factors and the SDPs success are identified. This study focuses on Qualitative Research approach and questionnaire is used as the technique of data collection. Participation selection is done through snowball sampling, making use of our network to make contact with organizations to ask for their willingness to participate. TWQ on SDP success is gaining an increasing interest within both academia and industry. The reasons for making this kind of research supporting strategic and operational management of SDPs to organize teams more efficiently and effectively. Our research work has ability to solve actual delay incurred by a software project due to lack of TWQ due to lower performance of team members. This is useful for Sri Lankan software industry to build and manage teams more constructively and adjust their management activities to improve team collaborations and team performance.Item The chromatic number of prime graph of a noncommutative ring Mn×n(Z2)(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Kolombage, K.A.D.D.B.V.; Wijesiri, G.S.Graph theory is a significant area of Mathematics as its outstanding applications in many fields such as biochemistry, electrical engineering, computer science and operational research. Besides Graph theory, Ring theory is an abstract area in Mathematics. A ring consists of a set equipped with two binary operations that generalize the arithmetic operations of addition (+) and multiplication(∗). Theorems obtained as a result of abstract study of rings can be applied to solve problems arising in number theory, geometry and many other fields. The study of rings with the help of graphs began when a graph of a commutative ring was defined by I. Beck in 1988. Then a new bridge was formed between graph theory and the algebraic concept “ring” noted as prime graph of a ring , denoted by () by B. Satyanarayana, K. Shyam Prasad, and D.Nagaraju in 2010. Later on with the help of existing concepts, K. Patra and S. Kalita investigated the chromatic number of prime graph, (ℤ) of ring ℤ for different values of . Prime graph of a ring is a graph whose vertices are all elements of the ring and any two vertices , of the vertex set are adjacent if and only if ∗ = 0 or ∗ = 0 and ≠ In this paper, we investigate the chromatic number of prime graph of some noncommutative rings ×(ℤ) for different values of n. The chromatic number of prime graph of some commutative rings are formed on the recognition of the conjecture that chromatic number, () and clique number are the same. But for non-commutative rings this is not always the case. Hence, in order to find the chromatic number of prime graph of a non-commutative ring, ×(ℤ), we have looked into MATLAB for a tactical solution.Item Localized modes of an electron by topological insulator defect(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Kumara, R.D.M.M.; Hewageegana, P.Topological insulators, a new class of materials discovered recently, have very unique topological properties. While the surface states are gapless and are topologically protected by the time reversal symmetry, the bulk of topological insulator shows a full gap. We study the properties of reflected and transmitted electron waves on the surface of topological insulator nanofilm with a defect. We show that an electron incident on a defect produces modes, which are localized at the defect. Such modes result in an enhancement of electron density at the defect. If an electron with a given energy E is incident on a region of the TI nanofilm which does not support electron propagating waves at energy E, then there is a strong enhancement of local electron density near the boundary of such region. We calculate the reflectance and transmittance of an electron from such a defect for different parameters of the topological insulator nanofilm and different parameters of the defect. The amplitude of the electron wave strongly depends on the position of electron energy. If electron energy is in the energy gap of defect, then the reflectance is 1. This result corresponds to total internal reflection. If the electron energy is not in the energy gap of defect, then the reflectance is small and the electron is almost totally transmitted. The critical points dividing these two boundaries are defined by the condition that the electron energy is at the band edge of energy dispersion. The dependence of the electron wave on the parameters of the system, such as thickness of the nanofilm or electron energy, is dominated near the critical points.Item Design and construction of low cost petri dish incubator(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Wanigasekara, G.; Perera, N.W.; Abeysinghe, D.; Geegamage, S.S.; Wijekoon, D.; Jayathilaka, N.Petri dish incubators are used in laboratories to keep petri dish samples at a stable and optimal temperature of 37 °C. Incubators are one of the frequently needed equipment. These incubators are expensive due to the use of complex systems. Many of the local universities do not have the necessary financial resources to purchase this equipment. Therefore, undergraduate students usually do not have access to incubators for academic learning. In order to surmount this challenge, it is necessary to look at a low cost, simple design for petri dish incubators. Hence, we have designed an incubator utilizing low cost microcontroller boards and sensors. Both microcontrollers and sensors were selected to provide adequate accuracy for the incubation at 37 °C. The incubator is constructed of three major components; sensors, controller and temperature regulation system. The incubator uses three LM35 temperature sensors to monitor the temperature with 0.5 °C accuracy and the system is controlled by Arduino Uno board with 16 MHz ATmega328P microcontroller. The microcontroller regulates the temperature of the incubation chamber utilizing 200W Nichrome heating element and two exhaust fans. Three temperature sensor readings were taken to acquire chamber temperature by averaging three values. Microcontroller uses these data to control the heating element, the fan for heating and the fan for cooling. The controller uses a PID (Proportional–Integral–Derivative) algorithm to stabilize the temperature. The sensor input wiring is highly shielded to avoid interference from the main powerline magnetic noise. The incubator body is shielded with porcelain to avoid fire hazards. The average temperature recorded by the incubator sensor and the chamber temperature as recorded with a thermometer was monitored at 2 hr intervals over a 16 hr period at 37.6 ± 0.5 °C and 37.6 ± 0.5 °C respectively indicating the accuracy of temperature regulation in the petri dish incubator over an extended period of incubation.Item Growth of CuZnS thin films by sequential electrodeposition and sulphurisation(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Fernando, W.T.R.S.; Jayathilekea, K.M.D.C.; Wijesundera, R.P.; Siripala, W.Copper Zinc Sulphide (CuZnS) is a promising new absorber material for solar cell applications. Indeed, this material is very attractive for low cost device applications due to abundance and low cost of the staring materials. Very recently, a CuZnS based solar cell with In2S3 window material has been reported having Voc of 0.41 V, Jsc of 10.6 mA/cm2, FF of 45% and of 1.94%. This initial finding has proven the possibility of developing this material as a solar energy material. Among the CuZnS preparation techniques, electrodeposition is an attractive technique because of its simplicity, low cost and possibility of making large area thin films. In this study, possibility of growth of CuZnS thin films by sulphurisation of electrodeposited Cu and Zn stack layers using S powder has been investigated. Cu thin film was electrodeposited on Ti substrate at –700 mV Vs Ag/AgCl for 15 min in an electrochemical cell containing 0.05 M sodium acetate and 0.005 M cupric acetate. Deposition of Zn thin film on Ti/Cu electrodes was carried out at -1.2 V Vs Ag/AgCl for 1 min in an electrochemical cell containing 0.2 M ZnSO4. Deposition parameters of Cu and Zn have been obtained by voltammograms. Set of identical Ti/Cu/Zn thin film electrodes having Cu/Zn ratio of 3.2 were prepared by maintaining the respective Cu and Zn thin film deposition durations for studying the sulphurisation process. In order to grow CuZnS, Ti/Cu/Zn thin film electrodes were annealed at different temperatures (400 oC, 450 oC, 500 oC, 550 oC and 600 oC) with different S contents (10 mg, 20 mg, 30 mg, 40 mg and 50 mg) for a duration of 60 min. CuZnS thin films were characterized using dark and light current voltage measurements in a PEC containing 0.1 M sodium acetate to obtain the best sulphurisation condition. Dark and light I-V characteristics revealed that the films annealed at 600 oC with the S content between 10 to 20 mg exhibits photoactivity. Further, photocurrent was always cathodic confirming the formation of p-CuZnS thin films. It was revealed in this preliminary investigation that the best photoactive films could be produced when films are annealed at 600 oC for 60 min in 20 mg S content. We have found, that photoactive p-CuZnS thin films can be grown by employing the technique of annealing electrodeposited Cu and Zn stack layers using S powder. Cu/Zn ratio of the stack layers could be the crucial parameter in determining the structure, conductivity type and resistivity of CuZnS films and therefore the methodology developed in this study could be further investigated, in order to develop the material for wider applications.Item Survey on ethnomedicinal uses of Eriocaulon ceylanicum in a selected division in Kuliyapitiya(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Wijesinghe, W.A.M.S.; Jayakody, J.A.D.P.P.Therapeutic effects and medicinal efficacy of the wild herbs were identified and administered by the ancient people to cure various ailments.Recently, the practice of herbal medicine has been diminishing, which may lead to the loss of valuable informations about healing herbs. There are many medicinal plants grown in semievergreen forests of Sri Lanka. This present study attempts to identify the use of traditional medicine and medicinal uses of Eriocaulon ceylanicum. A questionnaire survey was provided to randomly selected 200 people, of age between 30-80 years in Deegalla division located in Kuliyapitiya, West region of Kurunegla district. Study showed that only 36.5% of the respondents out of 200 were utilizing Eriocaulon ceylanicum for various ailments. Regarding the preparation method, 78.08% used the plant in fresh condition, 15.07% used both fresh and dry forms and 6.85% in dry form. According to the way of practicing, 60.28% used this plant as a source of food and 39.72% used as a remedy. Among those who utilized this plant as a remedy, it was used to treat Malnutrition (Māndama) (37.93%), burning sensation during urination (Mutra dāha ) (24.14%), leucorrhoea (Sweta pradara) (20.69%), anemia (Pāndu) (6.9%), skin disorders( Kushta ) (6.9%) and orthopedic conditions (Bhagna) (3.45%). .According to the indigenous medicnal texts Eriocaulon ceylanicum can be used to treat a wide range of ailments like Liver diseases (Yakrit roga), Spleenomegaly (Pleehāvriddi), Jaundice (Kāmalā), Alcohol-toxicity (Madātya), Pith roga, Dāha, Rathpith, Thirst (Trishnā), Vāta roga,Unmāda, Prameha, Pradara and, Soma roga. Despite its significant contributions, traditional medicine in Sri Lanka has attracted very little attention in research and development, and less effort has been made to uplift the role of traditional medicine practice. Thus, extensive research on such traditional plants is of prime importance to scientifically validate their ethnomedical claims.Item Semi-Automated Index based decision making engine for cyber foraging framework with minimal energy and performance cost(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Vekneswaran, P.; Dissanayake, N.R.Cyber Foraging is a concept to take advantage of the nearby underutilized computing resources (surrogates) to improve user experience of resource constraint handheld devices, by improving their performance while improving battery consumption. It’s not always beneficial to offload the tasks to the surrogates so there is a need for a decision making engine to only offload tasks, which will result in overall improvement in performance and battery consumption. There are many attempts to enable cyber foraging in smartphones, each having their own decision making mechanisms, some using fully automated Machine Learning Algorithms and Heuristic Data; and it has been proven inefficient even though with higher accuracy. Furthermore, these approaches fail to deliver accurate results when it comes to new applications without any historical data. The key drawback of them can be seen as the resource intensive decision making engine, which negatively effects on the overall performance and battery consumption of the device. We introduce a model for decision making engine, which takes context parameters like remaining battery, worst case complexity of the method, etc. into account, when making the choice to offload or not to the surrogate, during the runtime. The engine benchmarks the surrogate according to their capabilities such as: available JVM memory, accessible processing cores, which can be harnessed by the surrogate service used by the cyber foraging enabled mobile application using static policies. These indexes will then be used to compare with the worst case complexity value, which the developer has assigned to the identified intensive parts of the application. This approach will give a satisfactory amount of accuracy with extremely low cost of energy and higher performance. Further research is being done on addressing more complex use cases with more advanced algorithms towards a stable and reliable solution.Item Accelerating the rate of convergence of some efficient schemes for two-stage Gauss method(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Chamaleen, D.B.D.; Vigneswaran, R.The non-linear equations obtaining from the implicit s – stage Runge-Kutta methods have been solved by various iteration schemes. A scheme has been developed, which is computationally more efficient and avoids expensive vector transformations. The rate of convergence of this scheme is examined when it is applied to the scalar test differential equation = and the convergence rate depends on the spectral radius [()] of the iteration matrix (), where = ℎ and ℎ is the step-size. In this scheme, supremum of a lower bound for [()] is minimized over the left half - plane with the constraints requiring super-linear convergence at = 0 and → ∞ .Two new schemes with parameters are obtained for the two-stage Gauss-method. Numerical experiments are carried out in order to evaluate and compare the efficiency of the new schemes and the original scheme. Consider an initial value problem for stiff system of ordinary differential equations = (), () = , : ℝ → ℝ. An s-stage implicit Runge-Kutta method computes an approximation to the solution x () at discrete point = + ℎ by = + ℎ Σ ( ), where , ,…,, satisfy sn equations + ℎ , ), = 1,2, . . . , . = is the real coefficient matrix and = [ , ,…,] is the column vector of the Runge-Kutta method. Let = ⊕ ⊕ … ⊕ ∈ ℝand () = () ⊕ () ⊕ … ⊕ () ∈ ℝ. Then the above equation in , ,…, may be written by = ⊗ + ℎ( ⊗ )(), where = (1,1, … ,1) and ( ⊗ ) is the tensor product of the matrix with × identity matrix . The efficient scheme, which has been already proposed, is given by [ ⊗ ( − ℎ)] = ( ⊗ )( ⊗ – ) + ( ⊗ )( ⊗ – ) + ℎ( ⊗ )() + ℎ( ⊗ )(), = 1,2, …, In this scheme, supremum of a lower bound for [()] is minimized over ℂ, where ℂ = { ∈ / () ≤ 0 } with the constraints [()] = 0 at = 0 and [()] = 0 at → ∞. The parameters for the two-stage Gauss method are obtained and Numerical experiments are carried out.Item Isolation and characterization of rhizobia from leguminous plants(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Wijesundera, S.H.; Halmillawewa, A.P.Rhizobia play a significant role in agriculture. Their ability to fix atmospheric nitrogen through formation of root nodules in leguminous plants contributes in increasing legume yield. The present study was carried out with the aim of isolating rhizobial strains from legume root nodules and characterizing them to check their potential to be developed into biofertilizers. Tests were performed to detect plant growth promoting traits such as phosphate solubilization, nitrate reduction, abiotic stress tolerance, which contribute towards sustainable agriculture. Four rhizobial strains, namely C1-n1 (from Vigna unguiculata), P3-n1 (from Arachis hypogaea), L1-n1 (from Vigna unguiculata ssp. Sesquipedalis) and L2-n1 (from Vigna unguiculata ssp. Sesquipedalis) were isolated. They were characterized based on their morphological and biochemical features. Preliminary identification of isolates was done by observing their growth on yeast extract mannitol agar with congo red as well as their reactions to Glucose peptone agar test, Hofers’ alkaline test, and Lactose agar test. The isolated strain L2-n1, was identified as a slow growing alkaline producing one according to its reaction on bromo thymol blue medium, while others were recognized as acid producing fast growers. This result was congruent with their growth rates as well. All isolates gave positive results for oxidase, catalase, urease, and nitrate reduction tests and a negative result for indole, methyl red, gelatine hydrolysis and starch hydrolysis test. Two strains (L1-n1 and P3-n1) gave a positive reaction to Voges- Proskauer test, while only L2-n1 gave a positive result for citrate test. No isolate was able to exhibit swarming motility and phosphate solubilization. Furthermore, the capability of these organisms to utilize six different carbon sources and produce mucus colonies was also tested. The degree of viscosity produced was compared visually. Strains grew well at 25 °C–38 °C range, while L1-n1 and P3-n1 were able to tolerate a temperature range of 6 °C – 55 °C, pH range of 5.0 - 9.0 and NaCl levels up to 5% (w/v). C1-n1 was able to tolerate a pH range of 3.0 - 9.0 and NaCl levels up to 2.5% (w/v), while L2-n1 showed a growth only at neutral pH and a NaCl level of 0.01% (w/v). Also majority of strains were able to tolerate the heavy metals tested (Cu, Cd & Pb) at different concentrations. Strain L1-n1 showed an antibacterial activity against Staphylococcus aureus. All isolates formed nodules during the plant infectivity assays which were performed using their original plant host species confirming their identity as rhizobia. Plasmids were not observed in any of the isolates after performing the Eckhardt gel electrophoresis. According to the above results, these isolates may not be useful as biofertilizers, as they do not exhibit plant growth promoting traits satisfactorily. However further studies are required to determine their nodulation and nitrogen fixing efficiencies.Item Determination of an eligible location for installation of a solar panel system in the University of Kelaniya using GIS(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Heshani, A.L.S.; Athukorala, S.M.W.; Leelarathna, W.D.S.R.; Weerasinghe, V.P.A.According to the international energy agency, the role of renewables continue to increase in the electricity, heating and cooling and transport sectors. Newly develop technology in photovoltaic cells that have the potential to dramatically increase solar power generation in the next two decades. Being closer to the equator, Sri Lanka has a great opportunity to have solar energy throughout the year almost 5-6 hours per day. Sri Lankan power supply organizations are mainly depending on diesel, coal and hydro power. Still we do not have enough sources to supply electrical energy throughout the country. All the energy sources except hydro power are not considered as environmental friendly since they emit high amount of carbon to generate power. Being the first Green University in Sri Lanka, University of Kelaniya has initiated many approaches for energy conservation within the University. This study was carried out to find out the most suitable location within the University for installation of a solar panel system using ArcGIS software. For this, surface area of roof of buildings, height of buildings, elevation of the land, disturbance from other structures such as buildings and trees were selected. Map layers were created by using high resolution satellite image. Surface elevation profile was created by using available contour lines. Building layer was digitized from the satellite image using ArcGIS software. After overlaying all layers together suitable roofs were selected for the solar panels to install. In order to find possible energy in the area, meteorological data was collected including minimum and maximum atmospheric temperature, rainfall, and sunshine hours from Welisara meteorological station which is the nearest meteorological station to the University. The mean values of meteorological parameters obtained for the past 8 months were as follows; maximum atmospheric temperature of 28.28 0C and minimum of 26.02 0C, rainfall of 171.92 mm and sunshine hours were 7.6 hours. After selecting suitable buildings from the map, visual observation was done to calculate roof area of each building manually. The building with the highest surface area and minimum disturbance from adjacent structures was selected as the best suited location. The best suited location was selected and also it shows the highest monthly average consumption of electricity among other university buildings. Apart from that suitable lands also can be considered. But as the availability of lands in the university premises is a limited factor, priority was given to the rooves of the buildings. It is easy to make 3D view of the University by using 3D Analyst, if there is a higher resolution Digital Elevation Model (DEM). Roof structure and the shape can be used to maximize the efficiency of solar panels. GIS can be used as a supportive tool in optimization of determining the best suited location for the solar panel installation.Item A survey on usage of canteens of University of Kelaniya by students of Faculty of Science(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Dias, S.N.U.P.; Priyasad, H.A.D.; Manamperi, D.K.S.; Kumara, M.S.M.S.; Sandaruwan, D.M.S.; Pramoda, K. A.D.A.; Fernando, T.S.D.; Rashmi, W.A.D.; Ravindran, U.M.; Dhananjani, W.T.; Pitigalaarachchi, P.A.A.C.; Attanayake, A.M.C.H.The university canteens while providing meals are an important meeting point for both students and staff members. There are several canteens within a university but service provided by canteens and therefore, students’ preferences for canteens may be different. This survey is based on five main canteens at the University of Kelaniya; Base, Gym, Hilton, Staff and Hostel canteens. The aim of this survey is to understand the usage of the canteens by students of the Faculty of Science. The objectives are to identify the frequently visited canteen of the students and the reasons for it, categorize the most visited canteen by gender, year of study, accommodation type, measure the satisfaction on available facilities of university canteens and classify the student expectations regarding the facilities. The survey was conducted during the period of September – November 2015. Among the 1394 students registered in the Faculty of Science, 255 respondents were randomly selected using simple random sampling method (without replacement). An appropriate questionnaire was developed in order to gather data and achieve the objectives. After a pilot survey was conducted, questionnaire was administered in person and online and also by interviewing busy students in order to collect data. The analysis reveals that the majority of students (41%) of the Faculty of Science visited Base canteen for their needs; whereas 25% visited Staff canteen and 22% visit the Gym canteen. The usage does not change irrespective of whether the student stays at the hostel, boarding place or home. The reason for using the Base canteen is convenience in reaching the canteen. Female students (49%) use the Base canteen whereas male students (38%) prefer to use Staff canteen. Lunch is the preferred meal compared to breakfast, dinner and other snacks. The majority of first year students visit the Base canteen, 2nd year students prefer to visit Gym and Staff canteens than the Base canteen and 3rd year students prefer the Base canteen. Majority of the students (29%) have ranked the condition of Base canteen as average and 14% have ranked as good. When considering the attitude of the staff members of the canteens, Base and Staff canteens’ employees have been highly ranked as ‘Average’ by most of the respondents (19% and 17% respectively) while ‘Good’ was marked by 15%. Most of the respondents have marked as ‘Average’ considering the service speed of canteens in the university and around 20% of students have claimed that the service speed is low over all canteens. In general, only 45% of the students are satisfied with the facilities provided by the canteens. Most of the students (23%) have requested to expand the space within the canteens and requested to have air conditioning, TVs and vending machines within the canteens. The survey discloses important findings about the usage of university canteens by students of the Faculty of Science.Item “Save me”: Alternative payment method for in-app purchases(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Choxmi, S.; Peter, S.The mobile smart phone has become the most sought after technology tool, among the younger generation of the world. Sri Lanka is no exception with mobile penetration at more than 100% with growth of smart phone usage growing exponentially. Gaming with the aid of computers has become a billion dollar business and the wide usage of mobiles meant that a wider audience has now access to such tools. Companies are moving away from broad based advertising to more targeted direct advertising to capture market share. Use of mobile apps is widespread and the potential for companies to generate revenue streams by tapping into these applications have huge potential. The business strategy adopted by some developers is to offer the game for free while progress in levels of the game require in-app purchases to improve the gaming success and gain competitive advantage among players. In the perspective of the developers, in-app purchasing done by the gaming individuals is the main revenue stream. In developing countries like Sri Lanka, players of these games are reluctant or unable to spend money to purchase these inapps, since there is no financial benefit other than succeeding in the game. The other reason is that credit card details should be provided to purchase them. Most young people do not have or have access to credit card facilities. Thus, developers of game products are inhibited due to the lack of monetary incentive to build new gaming products and the players are inhibited by not being able to utilize the total advantages provided by the game. “Save – me” is a product designed to overcome these constraints by introducing an alternative method for payment and thus provide an incentive for mobile game developers to expand their market and increase their revenues, leading to the development of the information technology sector in the country. The current revenue models used by game developers include, selling the game for a fixed amount as a onetime fee, generating revenue from advertising while providing the game at no cost, and product or service providers financing the cost of the game through use of virtual coins. The models were evaluated using cost-benefit and sensitivity analysis. The latter was selected for its innovativeness and the ability to address the issue in a cost effective manner. The web portal solution includes three stakeholders. i.e. gamers, developers and manufacturers of goods and services targeting the gaming segment of the population. The process will commence with manufacturers / distributors assigning a discount to their products, in order to boost their revenue. Instead of giving customers the monetary discounts, the manufacturers will purchase virtual coins from “Save me”, and assign those coins to selected games on the portal. Customers who have registered on the portal, can earn these virtual coins instead of the discount, by progressing through the game and collecting these virtual coins. They can then exchange these virtual coins by going to their local supermarket which acts as a distributor and exchange the coins for the physical product that the manufacturer wants to promote. The game developers will be sharing the revenue via the purchases done by the players together with the portal owner.Item An AHP approach to prioritize the distributor’s requirements while minimizing the transportation cost(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Madushika, I.K.; Wijayanayake, A.Academic and corporate interest in Supply Chain Management (SCM) has risen considerably in recent years as SCM has emerged as one of the major areas for companies to gain a competitive advantage. Basically, the three fundamental stages of a Supply Chain (SC) are, procurement, production and distribution. Among these three stages, distribution plays a vital role as it directly impacts both the SC cost and customer experience. Many models have been developed in the past to minimize transportation cost under different constraints, as the main cost of logistics is transportation. In fact, when the organizations run on cost cutting approaches, not all the customers are satisfied when the demand surpasses the supply. Therefore, to retain the most important customers a proper mechanism is needed to prioritize them. Previous studies have been addressed different problems in logistics and improved models have been developed to maximize the service level and customer satisfaction but prioritization of customers is still a gray area which remains in the logistics literature. One of the main hurdles for distributors is handling situations, where the demand is higher than the supply and selected set of orders have to be delivered. Therefore, the main objective of the study is to identify the most important customers to be delivered first, from the distributor’s perspective while minimizing the cost of transportation. In this study, Analytic Hierarchy Process is used to identify the most important customers to the organization, under different criteria, defined by the distributor. All the criteria and alternatives were compared pair-wisely to calculate the overall importance of the alternatives. A mixed integer linear programing model has been developed with priority values in order to minimize the transportation cost. The proposed model will satisfy the needs of the important customers first and then the rest of the customers will be satisfied with the remaining quantities. When comparing the results of the developed model and ordinary transportation model, the transportation cost is higher in the developed model than the general transportation model. However, the satisfactory level of meeting the demands of the important customers is almost 100%. Therefore, this model is more appropriate for the firms who value customer needs more than minimizing the transportation cost.Item Enumeration of yeast and mold in tea and herbs using different methods and culture media(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Jayashantha, E.T.; Asalaarachchi, G.; Abeygunawardena, S.I.The International Standard Organization (ISO) has recommended the use of Dichloran 18% glycerol agar (DG-18) to enumerate yeast and mold in food (ISO 21527-2:2008) with reduced water activity (aw < 0.95). This ISO method uses the Surface Spread technique (SS-t). According to the ISO standard procedure, pour plate method is allowed to perform after a proper validation of results using the same medium. The objective of this study was to compare the Pour Plate technique (PPt) and spread plate technique using DG18 agar medium to enumerate yeast & mold in tea and herbs (e.g. lemongrass). The DG 18 agar medium was also compared with Yeast extract Dextrose Chloramphenicol (YDC) agar to enumerate these microorganisms. The tea samples and the herbs obtained from tea industry were used as the matrices for this study because these components have a water activity a less than <0.95. The sample preparation and the test were performed according to the ISO 21527-2:2008 standard procedures. Total of 20 samples of herbs and tea were used in this microbiological testing programme and the results were statistically analyzed using Paired-t test, with Minitab-14. The DG-18 medium gave average yeast and mold counts in tea samples as 2.58±0.42 CFU (log)/g in SS- technique whereas PP technique gave 0.41±0.08 CFU (log)/g. The fungal burden in herbs was 2.69 ±0.54 CFU (log)/g (SP-t) and 2.17 ±0.89 CFU (log)/g (PP-t). The YDC medium using pour plate technique gave average yeast and mold counts for tea and herb samples as 2.44 ±0.44 CFU (log)/g and 2.88 ±2 CFU (log)/g respectively. The DG-18 agar medium with the same technique gave 2.52±0.43 CFU (log)/g and 2.46±1.5 CFU (log)/g. The statistical analysis indicated that the results obtained either using two different media or using two different techniques with DG 18 medium were not significantly different.Item Photosynthesis: Synthesis of what?(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Gunawardane, M.M.The term photosynthesis is often used to mean the entire chain of biochemical reactions, which is initiated by light and concluded by the synthesis of carbohydrates. This series of reactions has two clearly distinct stages. First, there is the synthesis of ATP and reduced coenzymes (e.g. NADPH) with the help of light energy. Next, ATP and a reduced coenzyme are used in the synthesis of carbohydrates (e.g. starch) from CO2. As the first stage involves light, it is known as the light reaction of photosynthesis, while the second stage, which does not require light, is known as the dark reaction of photosynthesis. The dark reaction in nature is not a process necessarily dependent on a photomediated activity, the light reaction. What dark reaction needs for the reduction of CO2 into organic carbon is a reduced coenzyme and ATP, and the source of those compounds does not necessarily have to be the light reaction. This review proposes that the dark reaction should not be described as part of photosynthesis. Dark reaction is not a process limited to organisms that use photo energy to produce ATP and reduced coenzymes. In fact, without any dependence on photo energy, it happens in nature in some non-photosynthetic chemotrophic organisms as well. Thus, the light reaction is not an essential precondition for the dark reaction. Furthermore, ATP and reduced coenzymes synthesized by the light reaction in nature are not entirely used for the dark reaction. As such, the light reaction is not an activity that leads only to the dark reaction. Since the dark reaction can occur independently from any photo-driven synthesis process, it should not be described as part of photosynthesis. Therefore, the term photosynthesis should be confined to describe only the light reaction, defining photosynthesis as the process in nature that synthesizes ATP and reduced coenzymes using light energy. Dark reaction, which describes fixation of CO2 in to organic compounds, is an activity carried out by photosynthetic organisms and certain chemolithotrophic bacteria as well. It can be appropriately described by the term autotrophy, defining it as the primary production of carbohydrates in the biosphere.Item Assessment of phytochemicals and antifungal effect of Croton aromaticus against postharvest fungal pathogens isolated from tropical fruits(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Wijesundara, S.A.D.T.L.; Kannangara, S.; Abeywickrama, K.Chemical control using synthetic chemical fungicides is still the most common method of controlling postharvest diseases of fruits. Plant extracts which are rich in antimicrobial secondary metabolites such as terpinoids, alkaloids, saponins and flavonoids could be possible alternatives for synthetic fungicides. Current study was focused on evaluating the antifungal effect of ethanolic extract of Croton aromaticus (Kappettiya) leaves in vitro against mycelial growth and the spore germination of postharvest fungal pathogens isolated from fruits of banana (Colletotrichum musae, Rhizopus sp., Lasiodiplodia theobromae) papaya (Rhizopus stolonifer, Colletotrichum gleosporioides, Lasiodiplodia theobromae) and mango (Alternaria alternata, Pestalotiopsis mangiferae, Lasiodiplodia theobromae). Surface sterilized diseased banana, papaya and mango fruit tissues were cultured on PDA plates in order to obtain pure cultures of possible fungi and they were identified by morphological and microscopic characteristics, using identification keys. Inhibitory effect of the ethanolic extract of C. aromaticus against test pathogens were investigated by well diffusion method using PDA medium, by incorporating crude extract dissolved in DMSO, ranging from 1 mg/ml up to 300 mg/ml concentrations along with the positive (Captan) and negative (DMSO) controls. Significant (P < 0.05) inhibitory effects were exhibited by the ethanolic extract of C. aromaticus leaves against all test pathogens except L. theobromae. The highest mycelial growth and spore germination inhibition of most of the pathogens were observed at 100 mg/ml. The lowest Minimum Inhibitory Concentration of the leaf extract (5 mg/ml) was observed for spore germination inhibition of C. gleosporioides and P. mangiferae. TLC analysis revealed four compounds having Rf values of 0.551, 0.672, 0.810 and 0.913. Phytochemical screening of ethanolic extract revealed the presence of alkaloids, terpenoids, quinones, phytosterols and flavonoids. Current findings indicate the potential use of ethanolic extract of C. aromaticus leaves in controlling banana, papaya and mango postharvest fungal pathogens in vitro.Item Assessing potential biological hazards associated with Kelani River water using Nile tilapia (Oreochromis niloticus) as an aquatic model species(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Ruvinda, K.M.S.; Pathiratne, A.Kelani River receives complex mixtures of pollutants from diverse sources which include waste from industries, agriculture, domestic and municipal sources. However, scientifically based evidences on biological impacts associated with the Kelani River water are limited. Nile tilapia (Oreochromis niloticus) is a practically feasible aquatic model for toxicological assessments under tropical conditions. The present study assessed erythrocytic nuclear abnormalities (ENA), hepatic ethoxyresorufin O-deethylase (EROD) and hepatic glutathione S-transferase (GSTs) activities of Nile tilapia following exposure to selected surface water samples collected from the Kelani River and its tributaries in order to assess the potential biological impacts. Fingerlings of fish were exposed to surface water samples from an industrial effluent receiving canal (Menikagara ela; Site B), canal confluent (Site M), downstream of Kelani river at Sedawatta (contaminated with oil installation complex effluents and house hold waste; Site S) and up stream of Kelani river at Ruwanwella (reference site; Site R) and aged tap water (as controls) for 10 days under static renewal conditions. Physico-chemical parameters of exposed water were measured using standard analytical methods. Blood and liver samples of the exposed fish were collected from each treatment after 5 and 10 days of exposure, and ENA and EROD and GST tests were performed using standard methods. Water quality parameters indicated high levels of chemical oxygen demand, biochemical oxygen demand, total dissolved solid, salinity and conductivity and elevated levels of total phosphate content, nitrate content, heavy metal Cr, Cu and Pb levels in the water collected from the Sites B, M and S compared to tap water (P <0.05). Frequencies of total ENA were significantly higher in the fish exposed to water from the sites B, M and S compared those of the fish exposed to the tap water for 5 and 10 days. Blebbed and notched nuclei contributed mainly to the induction of total ENA than micronuclei and nuclear buds. Total number of nuclear abnormalities was elevated by the 10th day of exposure. Hepatic EROD and GST activities of the fish exposed to polluted water were not significantly different (P >0.05) from those of the fish exposed to tap water, but the enzyme activities were increased in each treatment at 10th day of exposure. Comparison of nuclear abnormalities and hepatic EROD & GST activities of O. niloticus together with physico-chemical analysis revealed that Sites B, M and S of Kelani River are contaminated with organic and inorganic xenobiotics, which may pose harmful cyto-genotoxic impacts on the feral fish populations.Item Analysing mobility patterns of people to determine the best transportation method(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Senanayake, J.M.D.; Wijayanayake, W.M.J.I.With the technological enhancements related to Internet, Wireless Communication, Big Data Analytics, Sensor-based Data, and Machine Learning; new paradigms are enabled for processing large amount of data which are collected from various sources. In the past decades, both coarse and fine-grained sensor data had been used to perform location-driven activity inference. In recent years, GPS phone and GPS enabled PDA become prevalent in people’s daily lives. With such devices people become more capable than ever of tracing their outdoor mobility and using locationbased applications. Based on the collected data from these GPS enabled devices with the help of IoT related to user mobility lots of research areas are opened. In this research the data related to user locations when users do any outdoor movements is collected using the mobile devices that are connected to the Internet and is mined using data mining techniques and come up with an algorithm to model & analyse those big data to identify mobility pattern, traffic prediction, transportation method satisfaction etc. The data for this research will be collected using a mobile application which has to be installed in smart devices like smart phones, tablet PCs etc. In this application the user has to enter the activity that he or she currently doing and the method of transportation & the users' opinion on the transportation method if he is doing some sort of travelling. The GPS coordinates (longitude & latitude) as GPS trajectories along with the time stamp and the date will be automatically acquired from the users' IoT device. A cloud based storage will be used to store collected data. Since the dataset is going to be a huge one, there can be data which contains outlier values due to the uncertainty of the mobile network coverage and the GPS coverage of the devices. Therefore, these data should be properly cleaned when doing data mining activities otherwise these data will lead to incorrect results such as wrong traffic prediction in certain places if several users are stuck in the same GPS coordinates for a while. Not only that but also when it comes to the user satisfaction, it might lead to generate incorrect outcome if the users in the sample will not enter their satisfaction accurately. This can be avoided by comparing cluster wise users with the consideration of the location and the transportation method. We can get the average opinion of the users and take it as the satisfaction of the transportation method in that cluster. Using the final results of this research the government can also be benefited if we selected the sample users well with mixing all the types of people and by providing necessary information for planning smart cities.Item Applicability of unsupervised learning algorithms for setting profiles for consumer buying behavior(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Paranavithana, I.R.; Rupasinghe, T.D.The Consumer Buying Behaviour consists of a summation of attitudes, preferences, intentions and, decisions taken by them. The process that customer buys a product or service varies for each individual and each category of products they may purchase. With the development of Information Technology, the products and the behaviour of purchasing those products have drastically changed and become more unique to individuals. With respect to these changes, the data collection and analysis have become more dynamic and customer data has become larger and nosier in terms of volume and complexity. As a result of that, handling, analysing, and interpreting customer Point of Sale (POS) data has become a challenge for Retail Supply Chains (RSC) who wish to segregate customers into specific niche markets. Furthermore, it makes increasingly difficult for the retailer to find out when a person comes and buys the products from their outlets and to predict his/her behaviour for the subsequent purchases. As a solution for the aforementioned problems faced by the retailers, a novel a consumer buying behaviour profile mechanism is proposed. The profiles are created with respect to the frequency, time-stamp, and product category using a large POS dataset. The Unsupervised learning techniques were utilized in categorizing consumers in determining similar purchasing behaviour using K-means, Expectation Maximization, and Hierarchical Agglomerative Clustering (HAC). Along with the above clustering techniques, text mining techniques were used in categorizing the product descriptions to create the desired product categories. The study has used data from the UCI machine learning repository with 541,909 POS type records and has applied the aforementioned unsupervised learning techniques to setup the profiles. It has unveiled product related and non-product related charateristics for the given POS data and has laid a novel foundation to construct the profiles to determine buying behaviour. Furthermore, these profiles can be used in segmentation of consumers, RSC specific promotions, and to predict future possibilities to minimize inventory related problems.Item Developing a model to identify the fade-away-impact of promotional activities over the financial performance(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Suraweera, S.A.M.S.; Wijayanayaka, A.The lack of understanding on the impact of marketing activities on financial performance had made the validity of and the effectiveness of marketing, a questionable one. When a particular promotional tool is used, the impact of that particular promotional activity is not restricted to the current period, but the effect permeates across future periods as well. The study identifies this impact as ‘fadeaway- impact’ of promotional activities on the financial performance. Currently promotional activities are considered as costs which are deducted from revenues of the same month. This idea restricts the impact of promotional activities only to short term results and completely ignores the medium and long term impact of promotional activities on the revenue. The purpose of this study is to develop a model to identify whether there is a fade-away-effect of promotional activities over the financial performance and identify how the impact behaves over the time. Promotional activities brings tangible and intangible benefits. Most of the marketing literature is focused on understanding the immediate/short term impact of promotional activities on the financial performance. This motivates the use of longterm or persistence models instead of event windows to study the impact of tangible and intangible effects. In order to reach the above mentioned objectives, the researchers use the Lagging Effects of regression model and Markov Chain related theories. Steady state vectors of the Markov process understand how the impact of promotional activities varies over time when a customer repeatedly purchase a given brand/ product or switch to a different brand. Data related to Markovian analysis have been collected from a questionnaire and tested. Apart from this, the lagging effect of linear regression models were used to assess which degree of lagging period of promotional cost is significant to the financial performance. The monthly promotions expenditures and the related revenue figures were collected from different firms to study the lagging effect. The findings reveal that the impact of promotional activities have a lagging-effect on the firm’s revenue/financial performance by proving the significant existence of 2nd and 3rd order lags in the simple linear regression model. Further, it proves through the Markov process that the impact of promotional activities will never go to zero, but it will become steady creating brand equity for the firm after a certain period and that period could be measured in which the researchers identifies as the period of fade-away-impact. The outcomes of the research enables the Marketing managers to make informed decisions on the selection of promotions mix tools and thereby to manage the promotional expenditures effectively without reducing their profitability.