Browsing by Author "Abdul Aziz Jemain"

Now showing 1 - 7 of 7
  • No Thumbnail Available
    ItemMetadata only
    Kajian simulasi kadar negatif palsu dengan min masa kembara.
    (Penerbit UKM) Abdul Aziz Jemain
  • Thumbnail Image
    ItemRestricted
    Mixed log series geometric distribution for sequences of dry days
    (Elsevier, 2009) Sayang Mohd Deni; Abdul Aziz Jemain
    The development of rainfall occurrence models is continuously being explored by a number of researchers in the field since the 20th century. In order to further enhance the development of rainfall occurrence modeling, this present study is aimed to propose a new probability model which is able to describe the daily series of rainfall occurrence, particularly on the duration of consecutive dry or wet days in Peninsular Malaysia.
  • Thumbnail Image
    ItemRestricted
    Perbandingan Pelbagai Kaedah Imputasi bagi Data Lenyap untuk Data Kualiti Udara
    (Penerbit UKM, 2015) Nuryazmin Ahmat Zainuri; Abdul Aziz Jemain; Nora Muda
    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).
  • No Thumbnail Available
    ItemMetadata only
    Residuals, outliers and influential observations in regression analysis
    (Penerbit UKM) Abdul Aziz Jemain; Collett Dave
  • Thumbnail Image
    ItemOpen Access
    Spatial patterns and trends of daily rainfall regime in Peninsular Malaysia during the southwest and northeast monsoons: 1975-2004
    (Springer, 2010) Jamaludin Suhaila; S. M. Deni; Wan Zawiah Wan Zin; Abdul Aziz Jemain
    This study focuses on describing the patterns and trends of five selected rainfall indices in Peninsular Malaysia, based on daily rainfall data from 1975 to 2004. Five rainfall indices based on two main seasons, the northeast and southwest monsoons, were analyzed: total rainfall, frequency of wet days, rainfall intensity, frequency of wet days (extreme frequency), and rainfall intensity (extreme intensity) exceeding the long-term mean 95th percentile.
  • Thumbnail Image
    ItemRestricted
    Trend and status of air quality at three different monitoring stations in the Klang Valley, Malaysia
    (Springer, 2010) Siti Zawiyah Azmi; Mohd Talib Latif; Aida Shafawati Ismail; Liew Juneng; Abdul Aziz Jemain
    Over the last decades, the development of the Klang Valley (Malaysia), as an urban commercial and industrial area, has elevated the risk of atmospheric pollutions. There are several significant sources of air pollutants which vary depending on the background of the location they originate from. The aim of this study is to determine the trend and status of air quality and their correlation with the meteorological factors at different air quality monitoring stations in the Klang Valley. The data of five major air pollutants (PM10, CO, SO2, O3, NO2) were recorded at the Alam Sekitar Sdn Bhd (ASMA) monitoring stations in the Klang Valley, namely Petaling Jaya (S1), Shah Alam (S2) and Gombak (S3). The data from these three stations were compared with the data recorded at Jerantut, Pahang (B), a background station established by the Malaysian Department of Environment.
  • No Thumbnail Available
    ItemMetadata only