LMS
Address

Department of Mathematical Sciences,
Faculty of Applied Sciences,
Wayamba University of Sri Lanka,
Kuliyapitiya,
Sri Lanka.

Telephone

+94 37 2283170

Fax

+94 37 2283170

Email

maths@wyb.ac.lk

Dr. (Mrs.) N.A.D. N. Napagoda
B.Sc. (Hons.) (Kelaniya), M.Sc. (Colombo), Ph.D. (CCNU)
Senior Lecturer (Grade I)

Telephone
E-mail

+(94) 37 2283170
namaleen@wyb.ac.lk

Google Scholar

  • 2018 –PhD in Bioinformatics, Central China Normal University, P.R.China.
  • 2011– MSc in Applied Statistics, University of Colombo, Sri Lanka.
  • 2006 – BSc (Special) Degree in Statistics and Pure Mathematics, University of Kelaniya, Sri Lanka.
  • National Science Foundation (NSF)
  • Institute of Applied Statistics Association (IASSA)
  • Sri Lanka Association for the Advancement of Science (SLAAS)
  • Youth Science Foundation (YSF)
  • Data Mining
  • Machine Learning
  • Bioinformatics
  • Big Data Analytics
  • 2nd Runner–up for Best Research Award –Open Category (Supervisor), Institute of Applied Statistics in 2025.
  • Gold Medal for Best Undergraduate Research Project (Supervisor), Institute of Applied Statistics in
  • Certificates of Recognition for Publications in Indexed Journals, Wayamba University Research Congress (WURC) in 2020.
  • Gold Medal for Best Research Project, Institute of Applied Statistics in
  • Excellent International Student Award for Outstanding Academic Achievement and Excellent Behavior (2015-2018) from the Central China Normal University, P.R.China.
  • Certificates of Academic Diligence (2016-2017) awarded by the Central China Normal University, P.R.China.
  • Chinese Government Full Scholarship for Post Graduate Studies. (2015-2018).
  • Gold Medal for Best Postgraduate Research Project, Institute of Applied Statistics in 2011.

Indexed / Refereed / Peer Reviewed Journal Papers

  • Napagoda, N.A.D.N., & Kumarasinghe, P.B.W.S.R. (2025) The Lee-Carter approach for life expectancy analysis and mortality forecasting in Sri Lanka, Journal of Science of the University of Kelaniya, 18(1), Pp 73 83.
  • Gayathri Y.K.K.M.K., & Napagoda N.A.D.N. (2025). Evaluating Clustering Methods for Heart Disease Analysis, Journal of Information and Communication Technology, (ISSN 2961-5992),2, Pp 1-5.
  • Kumarasinghe P.B.W.S.R., E.M.P. Ekanayake, A.D.N. Napagoda (2024). Survival Analysis of Primary Biliary Cirrhosis Patients, Vingnanam Journal of Science, 9(1), Pp 7-19.
  • Munasingha M.A.P., & Napagoda N.A.D.N. (2022). Statistical Approach of Identifying Crime Hotspots for GIS Mapping in Sri Lanka, Sri Lankan Journal of Applied Statistics, 23 (2), Pg 88-104.
  • Munasingha M.A.P. & Napagoda N.A.D.N. (2021). Trend Analysis and Forecasting for Paddy Production in Sri Lanka, Journal of Applied Economics and Business, Vol
  • Lakshani J.A.D.S. & Napagoda N.A.D.N. (2021). An Empirical Study for Life Insurances: A Case Study of Piliyandala Region, International Journal of Engineering Applied Sciences and Technology, Vol 5, Pg 72-76.
  • Napagoda N.A.D.N. (2019). An Integrated Multivariate Group Sparse Approach to Identify Differentially Expressed Genes of Breast Cancer Data, International Journal of Data Mining and Bioinformatics, Vol 22, Pg 149-170.
  • Napagoda N.A.D.N. (2019). A Selective Overview of Statistical Methods for High Dimensional Data, International Journal of Engineering and Future Technology [ISSN 2455-6432], Vol 16, Pg 28-38.
  • Napagoda N.A.D.N. (2013). Modeling of Soil Temperature by Generalized Regression Neural Network in Bathalagoda Area of Sri Lanka, International Journal of Scientific Research and Reviews, Vol 02, Pg 7-12.
  • Napagoda A.D.N. & Tilakaratne C.D. (2012). Artificial Neural Network Approach for Modeling of Soil Temperature: A Case Study for Bathalagoda Area, Sri Lankan Journal of Applied Statistics, Vol 13, Pg 39-59.

Papers in International Conferences

  • Kumarasinghe P.B.W.S.R., Napagoda N.A.D.N., and Pradeepkumar U. (2026). Towards Climate-Smart Agriculture: A Big Data and Clustering Approach for Crop Risk and Yield Prediction Using Indian Agricultural Data, International Conference on Emerging Concepts and Research in Integrated Sustainable Adaptation (ECRISA), Arthur C Clarke Institute for Modern Technologies(ACCIMT), January 30, 2026.
  • Gayathri Y.K.K.M.K., & Napagoda N.A.D.N. (2026), A Hybrid Machine Learning Framework For Biomarker Discovery In Chronic Inflammatory Diseases: Beyond Atopic Dermatitis, International Research Conference On Emerging Concepts And Research In Integrated Sustainable Adaptation 2026 (ECRISA),  Arthur C Clarke Institute for Modern Technologies(ACCIMT), January 30, 2026.
  • Kumarasinghe P.B.W.S.R., Napagoda N.A.D.N., and Tharushika D.D.H. (2025). Building Trust in News: Safe and Interpretable Large Language Models for Detecting Misinformation. International Conference in Data Science 2025 (ICDS 2025), November 25, 2025, University of Colombo.
  • Tharushika D.D.H. & Napagoda N.A.D.N. (2025). A Machine Learning Approach to Actuarial Life Table Estimation in Lung Cancer Patients, International Conference on Actuarial Sciences (ICActS) October 11, 2025, SLIIT.
  • Kumarasinghe P.B.W.S.R. & Napagoda N.A.D.N. (2025). Latent Structures in Zero-Inflated Risk Domains: An Elastic–Tweedie Synergy for Claim Forecasting, International Conference on Actuarial Sciences (ICActS),  October 11, 2025, SLIIT.
  • Gayathri Y.K.K.M.K., & Napagoda N.A.D.N. (2024). Evaluating Clustering Methods for Heart Disease Analysis, 4th International Conference on Science and Technology (ICST), October , 2024. (Abstract).
  • Napagoda N.A.D.N. & Kumarasinghe P.B.W.S.R. (2023). Lee-Carter Approach for Forecasting the Mortality in Sri Lanka. The 9th International Conference of Sabaragamuwa University of Sri Lanka (ICSUSL), December 8, 2023. (Abstract).
  • Gayathri Y.K.K.M.K., & Napagoda N.A.D.N. (2022) A review on parametric and non- parametric gene selection techniques in microarray data. International Conference on Innovation and Emerging Technologies 2022,University of Sri Jayawardanapura.
  • Gayathri Y.K.K.M.K., & Napagoda N.A.D.N. (2022). An Overview of Parametric and Non-parametric Gene Selection Methods in Classification Approaches in Microarray Data, International Postgraduate Research Conference 2022, University of Kelaniya.
  • Uduweriya R. M. B. P. M. & Napagoda N. A. D. N. (2021). Clustering Online Retail Data set, Proceedings of the 8th Annual Research symposium (ITUMRS 2021), Pg 106.
  • Thilakarathna H.A.N. & Napagoda N.A.D.N. (2021). A case study of Recognizing Causes for Abnormal Lots in a Capacitor Manufacturing Process, Proceedings of Peradeniya university International Research Sessions (IPURSE2021), Pg 510.
  • Uduweriya R. M. B. P. M. & Napagoda N. A. D. N. (2021). Linkage Comparison on Agglomerative Clustering for Online Retail Dataset, Proceedings of the International Conference in Data Science 2021 (ICDS2021), Pg 34.
  • Napagoda N.A.D.N. (2017). GLIM: A Novel Approach for Feature Selection of High Dimensional Data, Proceedings of the International Statistics Conference 2018, Pg78.
  • Thilankani N, Prabodanie R, Karunarathne C. and Napagoda N. (2014). Efficient Control and Utilization of Rubber Waste using Mixed Integer Programming, Proceedings of a Nineteenth International Forestry and Environment Symposium, Sigiriya, Sri Lanka.
  • Napagoda N.A.D.N. (2013). Modeling of soil temperature by Generalized Regression Neural Networks in Bathalagoda Area of Sri Lanka, Proceedings of a National Conference on Current Research in Emerging science and Technology (CREST -2013), Department of Applied Science, Alwar institute of Engineering and Technology, Alwar, India.
  • Napagoda N.A.D.N. (2012). Identifying the agro climatic factors that optimize the rice yield through Association Rule Mining (ARM): A Case Study in Bathalagoda Area, Proceedings of the Young Scientists Forum Symposium 2011, National Science and Technology Commission, Sri Lanka.
  • Napagoda N.A.D.N. and Tilakaratne C.D. (2011). Artificial Neural Networks Approach for Modeling of Soil Temperatures: A Case Study for Bathalagoda Area, Proceedings of the International Statistics Conference 2011, Colombo, Sri Lanka.

Papers in Local Conferences and Published as Full Articles

  • Upamali G. I, & Napagoda N.A.D.N. (2026). Multi-Class Classification of Financial Market Growth and Interest -Level Trends Using CNN and LSTM  , Proceeding of the 17th Symposium 2026, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Kaushalya H.W.S. & Napagoda N.A.D.N. (2026). Performance Evaluation of CNN and RNN Architectures in Predicting the Stock Market Price Index , Proceeding of the 17th Symposium 2026, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  •  Tharushika D.D.H. & Napagoda N.A.D.N. (2025). Lasso Regression Modeling for the Prediction of Solar Energy Generation With Meteorological Data, Proceedings of the 13th Annual General Meeting, Institute of Applied Statistics ,Colombo ,Sri Lanka.
  • Tharushika D.D.H. & Napagoda N.A.D.N. (2025). Risk Scoring for Loan Default Probability Using Gradient Boosting Machines Techniques, Proceeding of the 16th Symposium 2025, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Thilakarathna H.A.N. & Napagoda N.A.D.N. (2024). Root Cause Analysis Of Abnormal Lots In Manufacturing: A Statistical Approach, Proceedings of the 12th YSF Symposium, Young Scientists forum, Pp 208-216. (ISBN: 978-955-8630-32-7).
  • Silva C.N.S, Napagoda N.A.D.N. (2024). Discovering Influential Factors in Employee Attrition using Multivariate Analysis of Variance, Proceeding of the 15th Symposium 2024, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Gayathri Y.K.K.M.K., and Napagoda N.A.D.N. (2023). Lung Cancer Diagnosis Using the Lloyd K-means Algorithm, Proceeding of the 14th Symposium 2021, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Wanasinghe W.A.K.T.K. & Napagoda N.A.D.N. (2021). Stock Market Price Forecasting using Autoregressive Integrated Moving Average Model, Proceeding of the 13th Symposium 2021, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Sandamali M.S.R. & Napagoda N.A.D.N. (2020). Association Rule Mining to Identify Customer Buying Behavior of a Supermarket: A Case Study, Proceeding of the 12th Symposium 2019, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Wijesinghe A.H.N. & Napagoda N.A.D.N. (2020). Analyzing Factors Associated with Consumers’ Buying Behavior in Modern Trade Retail Outlets, Proceeding of the 12th Symposium 2019, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Abeysinghe A.M.W.S.O, Dharmawardane PMN, & Napagoda N.A.D.N. (2020). Forecasting Weekly Electricity Breakdowns in North Western Province, Proceeding of the 12th Symposium 2019, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Thilakarathna H.A.N. & Napagoda N.A.D.N. (2019). Application of DMAIC Method to Minimize Defects in A Capacitor Manufacturing Process, Proceeding of the 11th Symposium 2019, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Napagoda N.A.D.N. (2018). Genes and Differential Networks Based on Microarray Data, Proceedings , Academic Sessions and 7th Annual General Meeting, Institute of Applied Statistics ,Colombo ,Sri Lanka.
  • Ranasinghe A.N. & Napagoda N.A.D.N. (2015). Identification and Analysis of factors affecting Missing Values in Survey data, Proceeding of the 7th Symposium 2015, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Srimali K.G.A.A. & Napagoda N.A.D.N. (2015). Multinomial Logistic Regression Approach for Identification Factors Affecting to Loans: A Study in Seylan Bank in Gampaha District, Proceeding of the 7th Symposium 2015, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Fernando S.D, Dharmawardane P.M.N. and Napagoda N.A.D.N. (2015). Analysis of Factors Influencing Agent’s Perspective towards the Lapsation of Life Insurance policies, Proceeding of the 7th Symposium 2015, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Lawangi B.D.R. & Napagoda N.A.D.N. (2013). Investigation of Services Quality and Customer Satisfaction of Digital Spatial Data, Proceeding of the 5th Symposium 2013, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Jayarathna H.G.D, Ekanayake E.M.P. and Napagoda N.A.D.N. (2013). Investigation of Root Causes for Machine Breaks Down in Engineering Department: A case study for Linea intimates, Proceeding of the 5th Symposium 2013, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.
  • Napagoda N.A.D.N. (2012).Identifying the agro climatic factors that optimize the rice yield through Association Rule Mining (ARM): A Case Study in Bathalagoda Area, Proceedings of the Young Scientists Forum Symposium 2011, National Science and Technology Commission, Sri Lanka.
  • Herath H.M.T.N, Perera L.D.R.D. and Napagoda N.A.D.N. (2012). Investigation of Customer Perception in Sri Lankan Mobile Broadband Industry for Enhancing Customer Base of Etisalat Lanka, Proceeding of the 4th Symposium 2012, Applied Science, Business and Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka.

Chapter of Book

  • Napagoda N.A.D.N. (2010). Assessing Students through Alternative Methods, In Jayasingha U.K, and Jayaweera A, (editors). Teaching Learning Assessment & Development in Higher Education, Staff Development Center, Wayamba University of Sri Lanka, Pg 305-315.

Supervision (MPhil)

  • Principal Supervisor – Kumarasinghe P.B.W.S.R., “Smart Conflict Prevention: Real-Time Event Prediction and Resource Optimization Using Reinforcement and Deep Learning Techniques” (2025–Present)

Postgraduate Research Evaluation (MSc)

  • Examiner and member of Viva-voice examination board of the M. Sc in Statistics dissertation of “Optimizing Threshold Value for Feed Forward Neural Network” submitted by W.P.J.M.Warnakula (FGS-MSc-STAT-2023-004), 2025, Department of Statistics & computer Science, University of Kelaniya.
  • Examiner and member of Viva-voice examination board of the M. Sc in Statistics dissertation of “Assessing Spatiotemporal Variability in Fish Stocks using Environmental and Fisheries Data: A Case Study on Indian Ocean” submitted by E.M.A.P Edirimanna (FGS-MSc-STAT-2023-027). 2025, Department of Statistics & computer Science, University of Kelaniya.
  • Examiner and member of Viva-voice examination board of the M. Sc in Applied Statistics dissertation of “A study on the Efficiency of Student support Services on Dropout Rates in a distance Learning Environment: A case study, December 20, 2013, University of Colombo, Sri Lanka.
  • Resource Person for the “Workshop on Logistic Regression”, Department of Business Management, Faculty of Business Studies & Finance, Wayamba University of Sri Lanka, 2025.
  • Resource Person (Industry) of the “Workshop on Mathematical and Statistical Modelling for Solving Real World Problems”, Department of Mathematics, Faculty of Science, University of Ruhuna, 2025.
  • Organizer of the “Workshop on Mathematical Sciences – Kyushu University, Japan” conducted by the Department of Mathematical Sciences, Wayamba University of Sri Lanka, 2018.
  • Workshop Coordinator of the “Workshop on Statistical Data Analysis for students” conducted by the Department of Mathematical Sciences, Wayamba University of Sri Lanka, 2015.
  • Resource Person for the Seminar on “Analyzing Quantitative Data using SPSS organized by the Department of Accountancy of Wayamba University of Sri Lanka, 2014.
  • Resource Person for the Teacher Training Program for GCE Advanced Level combined Mathematics teachers in North-Western Province: “Statistics” –organized by the National Institute of education (NIE) and the Mathematics division of Ministry of education, 2014.
  • Organizer of the “Workshop on Mathematical Sciences – Kyushu University, Japan” conducted by the Department of Mathematical Sciences, Wayamba University of Sri Lanka, 2014.
  • Workshop Coordinator of the Statistical Data Analysis with R Software conducted by the Department of Statistics, University of Colombo,2013.
  • Resource Person for the Workshop on Statistical Data Analysis Using SPSS/ MINITAB Packages, Wayamba University of Sri Lanka, 2012.

Curriculum Development and Program Strengthening

  • Reviewer for a Course Modules – B.Sc in Business Management and Analytics, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapitiya, 2025.

  • Reviewer for a course Module – MBA 2142- Computer Based Data Analysis, Department of Business Management, Wayamba University of Sri Lanka, Kuliyapitiya, 2020.

Member of Editorial Board / Panel of Reviewers

  • Reviewer, 13th Ruhuna International Science and Technology Conference (RISTCON 2026), January 21, 2026, University of Ruhuna, Sri Lanka.

  • Reviewer, 12 th Ruhuna International Science and Technology Conference, January 22, 2025, University of Ruhuna, Sri Lanka.

  • Reviewer, 10th Wayamba University Research Congress (WURC) 2025, November 7, 2025, Wayamba University of Sri Lanka.

  • Reviewer, International Conference on Applied and Pure Sciences (ICAPS 2025), Faculty of Sciences, University of Kelaniya, 2025.

  • Reviewer, the 15th Symposium on Applied Science, Business and Industrial Research (ASBIRES), March 15, 2024, Wayamba University of Sri Lanka, Sri Lanka.

  • Reviewer, 4th IASSL International Conference on Statistics and Data Science, December 28-29, 2024, the Institute of Applied Statistics, Sri Lanka.

  • Reviewer, International Conference on Applied and Pure Sciences (ICAPS 2021), Faculty of Sciences, University of Kelaniya, 2021.

  • Member of Editorial Board: The 17th Symposium on Applied Science, Business and Industrial Research (ASBIRES), January 7, 2026, Wayamba University of Sri Lanka, Sri Lanka.

  • Member of Publication Committee: The 17th Symposium on Applied Science, Business and Industrial Research (ASBIRES), January 7, 2026. Wayamba University of Sri Lanka, Sri Lanka.

  • Member of Editorial Board, 16th Applied Science, Business & Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka, 2025.

  • Member of Publication Committee: The 16th Symposium on Applied Science, Business and Industrial Research (ASBIRES), March 7, 2025, Wayamba University of Sri Lanka, Sri Lanka.

  • Member of Publication Committee: The 14th Symposium on Applied Science, Business & Industrial Research (ASBIRES), March 23, 2022, Wayamba University of Sri Lanka.

  • Member of Editorial Board: The 12th Symposium on Applied Science, Business and Industrial Research (ASBIRES), December 22, 2020, Wayamba University of Sri Lanka, Sri Lanka.

  • Member of Publication Committee: The 12th Symposium on Applied Science, Business & Industrial Research (ASBIRES), December 22, 2020, Wayamba University of Sri Lanka

  • Member of Editorial Board: The 11th Symposium on Applied Science, Business and Industrial Research (ASBIRES), November 06, 2019, Wayamba University of Sri Lanka, Sri Lanka.

  • Member of Publication Committee: The 11th Symposium on Applied Science, Business & Industrial Research (ASBIRES), August 07, 2019, Wayamba University of Sri Lanka.

  • Reviewer, the 7th Symposium on Applied Science, Business and Industrial Research (ASBIRES), August 05, 2015, Wayamba University of Sri Lanka, Sri Lanka.

  • Reviewer, Wayamba International Conference (WinC), August 29-30, 2014, Kuliyapitiya, Sri Lanka: Wayamba University of Sri Lanka, Sri Lanka.

  • Reviewer, the 5th Symposium on Applied Science, Business and Industrial Research (ASBIRES), August 07, 2013, Wayamba University of Sri Lanka, Sri Lanka.

Conference and Symposium Chair/Discussant Roles

  • Session Chair, Technical Session on 17th Applied Science, Business & Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka, 2025.

  • Session Chair, Technical Session on 9th Applied Science, Business & Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka, 2017.

  • Session Chair, Technical Session on 2nd Wayamba International Conference (WinC 2016), Wayamba University of Sri Lanka, 2016.

  • Member of Technical Session on 6th & 7th of Applied Science, Business & Industrial Research Symposia 2014/2015, Wayamba University of Sri Lanka.

  • Panel Member, Presentation Session on 5th Applied Science, Business & Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka, 2013.

  • Panel Member, 4th Applied Science, Business & Industrial Research Symposium (ASBIRES), Wayamba University of Sri Lanka, 2012.

Visiting Appointments – Undergraduate Level

  • Visiting Lecturer – INS 4173- Actuarial Science, Faculty of Business Studies and Finance, Wayamba University of Sri Lanka, Kuliyaptiya, 2020.
  • Visiting Lecturer – INS 4173- Actuarial Science, Faculty of Business Studies and Finance, Wayamba University of Sri Lanka, Kuliyaptiya, 2019.

Academic and Administrative Position

  • Member of Senate Research & Higher Degrees Committee, Wayamba University of Sri Lanka, Kuliyapititya, 2026.
  • Member of Faculty Higher Degrees Committee, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapititya, 2026.
  • Senior Treasurer of Zero Plastic Society of Wayamba University of Sri Lanka, 2025/2026.
  • Member of Programme Review -2020, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapititya.
  • Member of SER Writing Team -Programme Review -2020, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapititya.
  • Member of Scholarships, Staff Development & Ethics Committee, Department of Mathematical Sciences, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapititya,2020.
  • Faculty Orientation Coordinator – Faculty of Applied Sciences, Wayamba University of Sri Lanka, 2018/2019.
  • Faculty Orientation Coordinator – Faculty of Applied Sciences, Wayamba University of Sri Lanka, 2007/2018.
  • Member of Research, Development & Publication Committee, Department of Mathematical Sciences, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapititya,2013.
  • Member of Activity 3: Strength Soft Skills of Students: University Development Grants (UDGs) under the Higher Education for the Twenty- First Century (HETC) Project, 2010.
  • Member of Research, Development & Publications Committee, Department of Mathematical Sciences, Faculty of Applied Sciences, Wayamba University of Sri Lanka, Kuliyapititya,2009.