Displaying publications 1 - 20 of 28 in total

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  1. Abdul Aziz Jemain
    This paper presents the accuracy of age statistics in the 1991 census. The quality of age statistics were evaluated using Myers index and United Nations index. The indices obtained were compared to the indices of 1970 and 1980. This study found that age statistics for 1991 census are better than the previous censuses and in general the statistics are having high quality.
    Dalam kertas ini dibentangkan ketepatan statistik umur pada banci 1991. Kualiti statistik umur dinilai dengan menggunakan indeks Myers dan United Nations. Indeks yang diperoleh dibandingkan dengan indeks pada banci 1970 dan 1980. Kajian ini mendapati statistik umur banci 1991 lebih baik daripada hasil banci sebelumnya dan pada keseluruhannya ia mempunyai kualiti yang baik.
  2. Abdul Aziz Jemain
    This paper offers a technique to create a development index among districts. To determine the weight for each criterion in the index entropy theory was used. Two approaches for criteria normalization were also suggested. The data obtained from 1991 census conducted in Peninsular Malaysia were utilized as illustration.
    Kertas ini mencadangkan teknik pembinaan indeks kemajuan daerah. Teori entropy digunakan untuk menentukan pemberat bagi kriteria yang digunakan dalam pembinaan indeks. Dua pendekatan menormalkan data turut dicadangkan. Contoh pembinaan indeks dikemukakan berdasarkan kemudahan asas yang terdapat di daerah-daerah di Semenanjung Malaysia seperti yang diperoleh berdasarkan banci tahun 1991.
  3. Noriszura Ismail, Abdul Aziz Jemain
    This study suggests the regression models of Lognormal, Normal and Gamma for the construction of an insurance scoring system. Comparison between Lognormal, Normal and Gamma regression models were also carried out, and the comparison were centered upon three main elements; fitting procedures, parameter estimates and structure of scores. The main advantage of utilizing a scoring system is that the system may be used by insurers to differentiate between good and bad insureds and thus allowing the profitability of insureds to be predicted.
  4. Ani Shabri, Abdul Aziz Jemain
    Identification of the true statistical distributions for various hydrologic data sets is a major problem facing engineers. The four-parameter kappa distribution is a combination of the established distribution including the Generalised Extreme Value (GEV), Generalised Logistic (GL), Generalised Pareto (GP) and the Gumbel distribution were considered in this study. The main objective of this study was to develop the method of LQ-moments for the kappa distribution. The performance of the LQ-moments was compared with L-moments through eight problems using published data sets. The results showed that the performance of both methods, the LQ-moments and L-moments worked equally well.
  5. Ani Shabri, Abdul Aziz Jemain
    Sains Malaysiana, 2007;36:201-206.
    Sejak taburan normal ditemui dan ianya merupakan salah satu taburan yang penting dalam statistik, terdapat banyak pengujian statistik yang dibangunkan untuk menguji kenormalan data. Namun begitu masih tidak banyak kajian yang dilakukan untuk melihat kembali keupayaan pengujian statistik yang sedia ada. Sebahagian daripada pengujian statistik didapati mudah tetapi hanya sesuai untuk sesuatu keadaan. Dalam kajian ini, pengujian statistik berdasarkan statistik Cramer-von Mises cuba diperbaiki berdasarkan rumus Weibull. Kekuatan statistik yang baru ini dibandingkan kekuatan dengan statistik traditional Anderson-Darling (AD), Cramer von-Mises (CR), Kolmogorov-Smirnov (KS) dan Shapiro-Wilk (SW). Kajian simulasi berdasarkan beberapa taburan yang berbeza menunjukkan pengujian statistik yang dicadangkan paling sesuai untuk menguji kenormalan.
  6. Ani Shabri, Abdul Aziz Jemain
    Kaedah momen merupakan salah satu teknik termudah dan sering digunakan dalam statistik hidrologi. Bagaimanapun, penganggar momen selalunya memberikan kualiti yang rendah dan tidak sebaik penganggar L-momen terutamanya untuk taburan dengan tiga parameter atau lebih. Pada masa kini, banyak kajian analisis frekuensi serantau dalam hidrologi menggunakan gambar rajah nisbah L-momen untuk memilih taburan yang sesuai bagi data hidrologi dan meteorologi. Kelebihan utama gambar rajah nisbah L-momen adalah pemilihan beberapa taburan yang sesuai boleh dilakukan menggunakan satu graf sahaja. Tujuan utama kertas ini untuk melihat kembali LQ-momen dan untuk membangunkan gambar rajah LQ-momen berdasarkan penganggar median. Menggunakan data aliran banjir dari 73 buah stesen dalam Semenanjung Malaysia, kami meninjau kesesuaian pelbagai model kebarangkalian menggunakan gambar rajah nisbah LQ-momen dan dibandingkan dengan gambar rajah nisbah L-momen. Hasil kajian menunjukkan gambar rajah nisbah LQ-momen secara umumnya memberikan keupayaan yang baik sebagaimana gambar rajah nisbah L-momen dalam memilih taburan frekuensi dan ini membuatkan ianya sesuai untuk dijadikan sebagai pilihan yang menarik untuk digunakan dalam analisis frekuensi banjir.
  7. Noratiqah Mohd Ariff, Abdul Aziz Jemain
    Sains Malaysiana, 2012;41:1377-1387.
    Rainfalls data have been broadly used in researches including in hydrological and meteorological areas. Two common ways in extracting observations from hourly rainfalls data are the window-based analysis (WBA) and storm-event analysis (SEA) approach. However, the differences in the qualitative and quantitative properties of both methods are still vaguely discussed. The aim of studying these dissimilarities is to understand the effects of each approach in modelling and analysis. The qualitative difference is due to the way the two analyses define the accumulated rainfalls for observations which are referred to as rainfall and storm depths, respectively. The repetitiveness of rainfall depths provide nested structure while the storm depths are considered independent. The quantitative comparisons include their statistical and scaling properties that are linked by the self-similarity concept from simple scaling characteristics. If self-similarity concept
    holds, then the rainfall or storm depths follow simple scaling and the analysis would be simplified. The rainfall depths showed clearer simple scaling characteristics compared to the storm depths. Though the storm depths do not yield self-similarity for a large range of storm duration but the characteristics of simple scaling can be observed for a reduced range of the considered duration. In general, the context of the research and the region of the time interval and duration will be an important aspects to consider in choosing which method is best to use for analyzing the data.
  8. Maznah Mat Kasim, Abdul Aziz Jemain
    Sains Malaysiana, 2013;42:667-672.
    Keputusan terakhir yang dicari dalam menyelesaikan masalah berbilang kriteria ialah satu pangkat kedudukan unit yang dianalisis berdasarkan prestasi keseluruhan unit-unit tersebut. Satu cara untuk mendapatkan prestasi keseluruhan setiap unit adalah dengan menggabungkan prestasi dan wajaran kriteria masing-masing melalui pelbagai kaedah pengagregatan. Kajian tertumpu kepada penerapan tiga kaedah asas pangkat dalam menilai kepentingan kriteria yang melibatkan satu panel penilai dengan kewibawaan berbeza. Hanya dua pendekatan pengagregatan berasaskan kaedah pemurataan tertib berpemberat sesuai diutarakan agar hasil akhir boleh dicapai. Setiap pendekatan pengagregatan yang dicadangkan diringi dengan contoh pengiraan.
  9. Maznah Mat Kasim, Abdul Aziz Jemain
    Sains Malaysiana, 2012;41:353-360.
    Masalah berbilang kriteria merupakan satu masalah yang terdiri daripada satu kumpulan unit yang dinilai berasaskan beberapa kriteria tertentu. Keputusan terakhir yang dihajati ialah satu pangkat kedudukan unit yang dianalisis berasaskan prestasi keseluruhan masing-masing. Satu cara untuk mendapatkan prestasi keseluruhan setiap unit ialah dengan menggabungkan prestasi dan wajaran kriteria masing-masing melalui pelbagai kaedah pengagregatan. Kajian tertumpu kepada penerapan tiga kaedah asas pangkat dalam menilai kepentingan kriteria yang melibatkan satu panel penilai. Empat pendekatan pengagregatan berasaskan kaedah pemurataan tertib berpemberat dicadangkan untuk dimanfaatkan agar hasil akhir boleh dicapai. Setiap pendekatan pengagregatan yang dicadangkan diringi dengan contoh pengiraan.
  10. Nuzlinda Abdul Rahman, Abdul Aziz Jemain
    Sains Malaysiana, 2013;42:1003-1010.
    Infant mortality is one of the central public issues in most of the developing countries. In Malaysia, the infant mortality rates have improved at the national level over the last few decades. However, the issue concerned is whether the improvement is uniformly distributed throughout the country. The aim of this study was to investigate the geographical distribution of infant mortality in Peninsular Malaysia from the year 1970 to 2000 using a technique known as disease mapping. It is assumed that the random variable of infant mortality cases comes from Poisson distribution. Mixture models were used to find the number of optimum components/groups for infant mortality data for every district in Peninsular Malaysia. Every component is assumed to have the same distribution, but different parameters. The number of optimum components were obtained by maximum likelihood approach via the EM algorithm. Bayes theorem was used to determine the probability of belonging to each district in every components of the mixture distribution. Each district was assigned to the component that had the highest posterior probability of belonging. The results obtained were visually presented in maps. The analysis showed that in the early year of 1970, the spatial heterogeneity effect was more prominent; however, towards the end of 1990, this pattern tended to disappear. The reduction in the spatial heterogeneity effect in infant mortality data indicated that the provisions of health services throughout the Peninsular Malaysia have improved over the period of the study, particularly towards the year 2000.
  11. Nor Azura Md Ghani, Liong, Choong-Yeun, Abdul Aziz Jemain
    MyJurnal
    This paper is an attempt to perceive and order guns using a two-layer neural system model taking into account a feedforward backpropagation calculation. Numerical properties from the joined pictures were utilised for enhanced gun characterisation execution. Inputs of the system model were 747 pictures blackmailed from the discharging pin impression of five differing guns model, Parabellum Vector SPI 9mm. Components created from the dataset were further grouped into preparation set (523 components), testing set (112 components) and acceptance set (112 components). Under managed learning, exact results exhibited that a two-layer BPNN of 11-11-5 arrangement, with tansig/purelin exchange capacities and a “trainlm” preparing calculation, had productively delivered 87% right aftereffect of grouping. The order result serves to be progressed and contrasted with the previous works. Finally, the joined picture districts can offer some accommodating data on the grouping of gun.
  12. Nuryazmin Ahmat Zainuri, Abdul Aziz Jemain, Nora Muda
    Sains Malaysiana, 2015;44:449-456.
    This paper presents various imputation methods for air quality data specifically in Malaysia. The main objective was to
    select the best method of imputation and to compare whether there was any difference in the methods used between stations
    in Peninsular Malaysia. Missing data for various cases are randomly simulated with 5, 10, 15, 20, 25 and 30% missing.
    Six methods used in this paper were mean and median substitution, expectation-maximization (EM) method, singular
    value decomposition (SVD), K-nearest neighbour (KNN) method and sequential K-nearest neighbour (SKNN) method. The
    performance of the imputations is compared using the performance indicator: The correlation coefficient (R), the index
    of agreement (d) and the mean absolute error (MAE). Based on the result obtained, it can be concluded that EM, KNN
    and SKNN are the three best methods. The same result are obtained for all the eight monitoring station used in this study.
  13. Abdul Aziz Jemain, Al-Omari A, Kamarulzaman Ibrahim
    McIntyre was the first to suggest ranked set sampling (RSS) method for estimating the population mean. In this paper, we modify RSS to come up with new sampling method, namely, two stage ranked set sampling (TSRSS) for samples of size m=3k (k=1,2,..). The TSRSS is suggested for estimating the population median in order to increase the efficiency of the estimators. The TSRSS was compared to the simple random sampling (SRS), ranked set sampling (RSS), extreme ranked set sampling (ERSS), median ranked set sampling (MRSS) and balance groups ranked set sampling (BGRSS) methods. It is found that, TSRSS gives an unbiased estimator of the population median of symmetric distributions and it is more efficient than SRS. Also, it is more efficient than RSS, ERSS, MRSS and BGRSS based on the same number of measured units. For asymmetric distributions considered in this study, TSRSS has a small bias and smaller variance than SRS, RSS, ERSS, MRSS and BGRSS methods.
  14. Norshahida Shaadan, Sayang Mohd Deni, Abdul Aziz Jemain
    Sains Malaysiana, 2015;44:1531-1540.
    In most research including environmental research, missing recorded data often exists and has become a common problem for data quality. In this study, several imputation methods that have been designed based on the techniques for functional data analysis are introduced and the capability of the methods for estimating missing values is investigated. Single imputation methods and iterative imputation methods are conducted by means of curve estimation using regression and roughness penalty smoothing approaches. The performance of the methods is compared using a reference data set, the real PM10 data from an air quality monitoring station namely the Petaling Jaya station located at the western part of Peninsular Malaysia. A hundred of the missing data sets that have been generated from a reference data set with six different patterns of missing values are used to investigate the performance of the considered methods. The patterns are simulated according to three percentages (5, 10 and 15) of missing values with respect to two different sizes (3 and 7) of maximum gap lengths (consecutive missing points). By means of the mean absolute error, the index of agreement and the coefficient of determination as the performance indicators, the results have showed that the iterative imputation method using the roughness penalty approach is more flexible and superior to other methods.
  15. Nor Azura Md Ghani, Liong CY, Abdul Aziz Jemain
    Pengecaman senjata api semakin serius dan amat penting di dalam bidang penyiasatan jenayah khususnya untuk tempoh dua dekad ini. Dalam makalah ini, suatu sistem untuk pengecaman senjata api berasaskan tapak kelongsong peluru telah diperkenalkan. Tapak kelongsong peluru adalah satu daripada penunjuk yang amat penting dalam membantu menyelesaikan masalah pengecaman pistol. Peluru yang telah digunakan akan meninggalkan lebih daripada 30 ciri yang amat berharga pada tapak kelongsong bagi membantu pihak tertentu mengecam pistol yang telah diguna. Ciri-ciri tersebut sebagai suatu gabungan membentuk apa yang dikenali sebagai kesan cap jari bagi pistol. Lantaran itu, kajian ini adalah untuk mendapatkan fitur yang sesuai bagi pengecaman senjata api. Terlebih dahulu imej tapak kelongsong peluru ini telah ditemberengkan kepada tiga bahagian, membentuk tiga set imej yang berlainan. Imej-imej ini juga dilakukan prapemprosesan untuk membentuk tiga set imej lagi. Fitur-fitur seterusnya disaring daripada imej asal tapak kelongsong peluru dan imej yang telah melalui prapemprosesan. Dua puluh fitur yang berbeza secara signifikan telah diperoleh dan dikirakan untuk imej-imej asal dan yang telah dilakukan prapemprosesan. Kesemua pemprosesan telah dilakukan menggunakan pengaturcaraan MATLAB. Suatu skim berdasarkan analisis korelasi seterusnya telah diperkenalkan untuk pencarian fitur berdasarkan konsep meminimumkan lewahan data tetapi memastikan ciri-ciri unik tersimpan. Fitur-fitur yang berkorelasi tinggi akan digugurkan pasangannya dan hasilnya tinggal cuma tujuh fitur sahaja. Ketujuh-tujuh fitur ini telah diuji sebagai suatu vektor fitur untuk mengelaskan lima pistol daripada model yang sama menggunakan analisis diskriminan. Hasil pengelasan menunjukkan lebih 80% daripada imej-imej tapak kelongsong peluru itu telah dikelaskan dengan jayanya.
  16. Ratan Dewi Abdul Rahman, Norrakiah Abdullah Sani, Abdul Aziz Jemain
    Sains Malaysiana, 2012;41:1629-1634.
    Kajian ini bertujuan untuk memilih kaedah terbaik daripada sebelas kaedah pengiraan Escherichia coli dalam masakan ayam. Kaedah-kaedah tersebut adalah piring curahan, piring sebaran, piring titisan, PetrifilmTM, tiga jenis pemiringan terus dan empat jenis kaedah bilangan paling mungkin (MPN). Perbandingan kaedah dijalankan mengikut prosedur ISO 16140. Setiap strain E. coli (ATCC 25922, IMR 1/3 107B dan IMR E243) telah diinokulasikan ke dalam lima jenis masakan ayam bagi mendapatkan kepekatan bakteria sehingga 105 cfu/g. Perlakuan haba dibuat pada 55oC selama
    4-6 min bagi mewujudkan persekitaran yang seakan-akan sama seperti makanan tersebut dihidangkan sebaik sahaja selepas dimasak. Analisis statistik Regressi Kaedah Kuasa Dua Terkecil (KKDT) dijalankan bagi membandingkan sebelas kaedah pengiraan E. coli. Nilai kecerunan (m) yang signifikan (p < 0.05) pada kesemua Graf KKDT membawa maksud kesemua kaedah adalah serupa daripada segi kejituan, korelasi, dan ketepatan relatif. Oleh itu, penilaian praktikal turut dipertimbangkan bagi menentukan tiga kaedah terbaik bagi pengiraan E. coli dalam masakan ayam. Piring curahan, PetrifilmTM dan piring titisan adalah lebih praktikal berbanding lapan kaedah yang lain.
  17. Sanusi W, Abdul Aziz Jemain, Wan Zawiah Wan Zin
    Sains Malaysiana, 2014;43:1791-1800.
    Dalam kajian ini, pendekatan pengelompokan kabur Gustafson-Kessel (Gx) telah digunakan untuk mengelaskan 35 stesen hujan di Semenanjung Malaysia ke dalam rantau homogen. Pertama, algoritma pengelompokan kabur GK digunakan untuk mengenal pasti rantau awal. Kemudian, diuji keserasian dan kehomogenan rantau berkenaan. Akhir sekali, penyesuaian rantau dilakukan untuk mendapatkan rantau homogen. Hasil kajian mendapati 35 stesen hujan kajian boleh dibahagikan kepada enam rantau yang homogen. Rantau 1 meliputi bahagian barat laut dan utara Semenanjung Malaysia, rantau 2, 3 dan 4 meliputi bahagian barat, rantau 5 meliputi bahagian barat daya dan rantau 6 meliputi bahagian timur. Hasil kajian ini juga memperlihatkan bahawa berdasarkan nilai purata Indeks Kerpasan Piawai (sPi) skala masa satu bulan, rantau 2 lebih sering mengalami keadaan kemarau melampau. Walau bagaimanapun, berdasarkan sPi skala masa satu bulan, peristiwa kemarau terjadi secara rawak dalam semua rantau yang dianalisis , bahkan semua rantau tersebut pernah mengalami kejadian kemarau melampau dalam tempoh masa setahun. Hasil kajian ini turut menunjukkan bahawa pendekatan pengelompokan kabur Gustafson-Kessel boleh digunakan untuk membina rantau homogen.
  18. Rado Y, Wan Zawiah Wan Zin, Abdul Aziz Jemain
    Sains Malaysiana, 2014;43:359-367.
    Kajian ini bertujuan mendapatkan gabungan statistik untuk pemodelan hujan kelompok berstokastik Denyut Segi Empat Neyman-Scott (NSRP) yang mampu memberikan pemadanan terbaik bagi hujan di stesen hujan Semenanjung Malaysia. Enam set gabungan statistik, yang setiap setnya mengandungi gabungan statistik momen (1, 2 dan 3) dan kebarangkalian hujan dalam selang masa yang singkat (jam) dan panjang (harian), serta empat taburan yang berbeza bagi kelebatan sel hujan (Eksponen, Campuran Eksponen, Gamma dan Weibull) telah dikaji. Penyelidikan telah dilakukan ke atas sembilan stesen hujan yang mewakili rantau yang berbeza di Semenanjung Malaysia. Hasil mendapati bahawa statistik momen ke-3 (kepencongan) tidak memberikan sumbangan yang baik dalam menjayakan model. Selang masa 1, 6 dan 24 jam didapati yang terbaik bagi statistik momen kedua (variasi) bagi menjayakan model. Kajian ini juga mendapati bahawa taburan eksponen adalah yang terbaik bagi pemodelan hujan NSRP di Semenanjung Malaysia.
  19. Nor Hasliza Mat Desa, Maznah Mat Kasim, Abdul Aziz Jemain
    Sains Malaysiana, 2015;44:239-247.
    The issue of age difference in hospital admission should be given special attention since it affects the structure of hospital care and treatments. Patients of different age groups should be given different priority in service provision. Due to crucial time and limited resources, healthcare managers need to make wise decisions in identifying priorities in age of admission. This paper aimed to propose a construction of a daily composite hospital admission index (CHAI) as an indicator that captures relevant information about the overall performance of hospital admission over time. It involves five different age groups of total patients admitted to seven major public hospitals in the Klang Valley, Malaysia for respiratory and cardiovascular diseases for a period of three years, 2008 - 2010. The criteria weights were predetermined by aggregating the subjective weight based on rank ordered centroid (ROC) method and objective weight based on entropy - kernel method. The highest and lowest scores of CHAI were marked, while the groups of patients were prioritized according to the criteria weight ranking orders.
  20. Muhammad Fauzee Hamdan, Shariffah Suhaila Syed Jamaludin, Abdul Aziz Jemain
    MATEMATIKA, 2018;34(101):167-177.
    MyJurnal
    Rainfall is an interesting phenomenon to investigate since it is directly related
    to all aspects of life on earth. One of the important studies is to investigate and under-
    stand the rainfall patterns that occur throughout the year. To identify the pattern, it
    requires a rainfall curve to represent daily observation of rainfall received during the year.
    Functional data analysis methods are capable to convert discrete data intoa function that
    can represent the rainfall curve and as a result, try to describe the hidden patterns of the
    rainfall. This study focused on the distribution of daily rainfall amount using functional
    data analysis. Fourier basis functions are used for periodic rainfall data. Generalized
    cross-validation showed 123 basis functions were sufficient to describe the pattern of daily
    rainfall amount. North and west areas of the peninsula show a significant bimodal pattern
    with the curve decline between two peaks at the mid-year. Meanwhile,the east shows uni-
    modal patterns that reached a peak in the last three months. Southern areas show more
    uniform trends throughout the year. Finally, the functional spatial method is introduced
    to overcome the problem of estimating the rainfall curve in the locations with no data
    recorded. We use a leave one out cross-validation as a verification method to compare
    between the real curve and the predicted curve. We used coefficient of basis functions
    to get the predicted curve. It was foundthatthe methods ofspatial prediction can match
    up with theexistingspatialpredictionmethodsin terms of accuracy,but it isbetterasthe new
    approach provides a simpler calculation.
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