Spatial functional outlier detection in multivariate spatial functional data

Multivariate spatial functional data consists of multiple functions of time-dependent attributes observed at each spatial point. This study focuses on detecting spatial outliers in spatial functional data. Firstly, we develop a new method called Mahalanobis Distance Spatial Outlier (MDSO) to detect functional outliers in the data. The method introduces the multivariate functional Mahalanobis semi-distance and multivariate pairwise functional Mahalanobis semi-distance metrics based on the multivariate functional principal components analysis to calculate the dissimilarity between functions at each spatial point. Via simulation, we show that MDSO performs better than the other competing methods. Secondly, MDSO has been extended to detect spatial functional outliers as well. The functional outliers can now be categorized as global or/and local functional outliers. The appropriate number of neighbors and the cut-off point for the degree of isolation are determined via simulation. Finally, we demonstrate the application of the MDSO on a water quality data set obtained from Sungai Klang basin in Malaysia. The results can be used to support the authority in making better decisions on the management of the river basin or other spatial data with time-independent attributes

Improved spatial outlier detection method within a river network

A spatial outlier refers to the observation whose non-spatial attribute values are significantly different from those of its neighbors. Such observations can also be found in water quality data at monitoring stations within a river network. However, existing spatial outlier detection procedures based on distance measures such as the Euclidean distance between monitoring stations do not take into account the river network topology. In general, water quality levels in lower streams will be affected by the flow from the upper streams. Similarly, the water quality at some tributaries may have little influence on the other tributaries. Hence, a method for identifying spatial outliers in a river network, taking into account the effect of river flow connectivity on the determination of the neighbors of the monitoring stations, is proposed. While the robust Mahalalobis distance is used in both methods, the proposed method uses river distance instead of the Euclidean distance. The performance of the proposed method is shown to be superior using a synthetic river dataset through simulation. For illustration, we apply the proposed method on the water quality data from Sg. Klang Basin in 2016 provided by the Department of Environment, Malaysia. The finding provides a better identification of the water quality in some stations that significantly differ from their neighbouring stations. Such information is useful for the authorities in their planning of the environmental monitoring of water quality in the areas

The Determinants of Household Debt in Malaysia

This study aims to observe the determinants of the factors affecting household debt in Malaysia. This study has listed six independent variables that would affect Malaysia’s household debt: real interest rate, inflation rate, unemployment rate, household consumption expenditure, gross domestic product (GDP), and housing price index (HPI). This research was conducted by using annual data for 30 years (1991-2021); this study also used a quantitative approach to the collection of data using secondary data such as the website of the World Bank, Department of Statistics Malaysia, Eikon Thomson Reuters, and Bank Negara Malaysia. A theoretical model with the hypothesized relationships was tested with the help of the structural equation modelling procedures. Findings showed that the unemployment rate and gross domestic product have a positive and significant relationship with household debt. These determinants are directly affecting household debt in Malaysia, especially in microeconomic factors. This study will contribute to a better understanding that household debt can be influenced by other factors. Further study on the other determinants of household debt may result in varying results

Effects of Foliar NPK Application on Growth, Yield and Nutrient Content of Sweet Corn Grown on Rengam Series Soil

The present study was carried out to evaluate the effects of different rates of macronutrients as a foliar spray on the growth performance, yield, and nutrient content of sweet corn grown in the Rengam soil series. The treatments consisted of five rates of macronutrients as a foliar fertilizer at 0, 25, 50, 75, and 100 % NPK. Foliar NPK was applied 25 and 50 days after sowing to the sweet corn seedlings. The results showed that fresh cob weight, cob number, flowering, and dry matter yield of sweet corn significantly increased at the rate of 75%, and 100% of NPK foliar fertilizers. The macro and micronutrient concentrations in ear leaf, mature leaves, stem, cob, and flowers of 75 and 100% NPK treated corn were significantly increased over the control plants. The macronutrient content in the whole plant was also significantly higher at 75% and 100% NPK treatments. Fe and Mn contents in the whole plant were also the highest in 75% and 100% NPK treatments. Macronutrient concentration in ear leaf and whole corn plants significantly correlated with the fresh cob yield of corn. It is concluded that foliar application of N, P, and K macronutrients (75 to 100% NPK) enhanced the yield and quality of sweet corn

The Grease Formulation Using Waste Substances From Palm Oil Refinery And Other Industrial Wastes: A Review

Many applications use Spent Bleaching Earth (SBE) despite being considered hazardous waste from the palm oil refinery process. Its production increases yearly, similar to waste cooking oil (WCO). The SBE is known as a thickener in grease formulation. The same goes for red gypsum, waste motor oil, stearic acid, and lithium hydroxide monohydrate. They are all considered thickeners but have different durability in protecting base oil in grease. Then, previous studies revealed their performances with side effects detection against the environment and human bodies. Cooking oil is a heat transfer medium for serving foods with higher amounts of unsaturated fatty acids. The number of fatty acids might change after cooking oil consumption and become highly demanded due to the chemical properties of density, viscosity and fatty acids. Nowadays, people lack awareness of the importance of recycling palm oil waste. They intend to dispose of it instead of recycling it for sustainable energy resources. Therefore, this paper will discuss the grease formulation, contaminant available in WCO, its treatment, issues regarding different thickener consumption, treatment against Spent Bleaching Earth (SBE), and propose the safe thickener and additives for future intakes. This study found that adding Fume Silica (F.S.) as a thickener and Molybdenum Disulfide (MoS2) enhanced the grease stability. Further treatment against SBE (remove residue oil) and WCO (metal elements, undesired impurities and water content) is necessary for providing good quality formulated grease

Isolation of Candida species in children and their biofilm-forming ability on nano-composite surfaces

Candida species including Candida albicans, Candida krusei and Candida glabrata are opportunistic microorganisms that inhabit oral cavity. The objective of this study is to determine the effect of dental caries on Candida spp. biofilm-forming ability on nano-composite with the hypothesis that dental caries enhances the colonization of Candida spp. To assess Candida spp. colonisation in the oral cavity of the paediatric patient, samples were obtained from 30 subjects aged five to six years old from Kuantan, Pahang, Malaysia. The samples were collected from buccal mucosa, palate and tooth surfaces using sterile swabs. 10 mL of patient’s saliva suspension was also collected. Following that, the samples were inoculated on CHROMagar and incubated for 24 h at 37 ºC. Candida biofilm of caries isolate C. albicans (HNFC2), and C. albicans ATCC 32354 were developed on three different types of nano-composites. The study showed that no C. albicans was isolated from the caries-free oral cavity while 76% of children with caries possessed Candida spp. 65% of the yeasts were isolated from the tooth surface. Only 35% of the total isolates were obtained from soft tissues, including palatal and buccal mucosa. C. albicans is the most isolated Candida spp. with 82% and 67% of the yeast were obtained from the tooth surface and buccal mucosa, respectively. Besides, HNFC2 significantly colonised the nano-composites more than the ATCC (P < 0.05). In the comparison of the three types of nano-composites, nano-hybrid-based containing pre-polymerised filler (cB) exhibited the least C. albicans HNFC2 cells colonisation with 7.7 x 10³ cells mL-1. In contrast, the nano-composite that contained bulk-filled nanohybrid (cC) was the most colonised with 14.3 x 10³ cells mL-1. In conclusion, dental caries enhances the colonization of Candida spp. in children's oral cavity, and that caries isolate form more biofilm on nano-composites compared to the lab strain C. albicans

Leaf morphological variations and heterophylly in ficus deltoidea Jack (Moraceae)

Six varieties of Ficus deltoidea Jack (Moraceae) showed leaf morphological variations through quantitative measurement on different plant parts. There were significant differences among six varieties studied by plant parts. The varieties studied include var. deltoidea Corner, var. angustifolia (Miq.) Corner, var. trengganuensis Corner, var. bilobata Corner, var. intermedia Corner, and var. kunstleri (King) Corner. The upper, middle and lower plant parts showed morphological variations in terms of leaf length, leaf width, leaf area and petiole length. Qualitative parameters also showed trends in morphological variations in terms of leaf shape, leaf base, leaf apex and leaf attachment. However, some qualitative parameters were not the recommended parameters to differentiate among varieties. On the other hand, leaf heterophylly has occurred in F. deltoidea because foliage of the young plant was different from the mature plant. Leaf heterophylly was observed in leaf shape and leaf apex parameters, whereby leaves from the lower plant parts were different from the upper and middle parts. The heterophylly in leaf shape was detected in varieties angustifolia, bilobata, intermedia and trengganuensis, whilst six varieties of F. deltoidea showed leaf apex heterophylly

Flood analysis and non-structural approach for flood protection in Sg. Kelantan

Flooding is categorized as a natural disaster that occurs due to various climatic and geophysical factors. Malaysia is a lucky country as it experiences a tropical climate and generally protected from extreme drought. However, the states located along the east coast of the Peninsular Malaysia such as Kelantan, Terengganu, and Pahang always experienced a heavy flood, especially during the monsoon season due to high intensity of rainfall. The objectives of this paper were to simulate Flood Hydrographs for Various Storm Duration by using Hydrologic Engineering Centre-Hydrologic Modelling System (HEC-HMS), to investigate the location of floodplain at the catchment area of Sg. Kelantan by using River Analysis System (HEC-RAS), to identify the non-structural approach that can reduce the rate of flood based on its topography. By using HEC-HMS and HEC-RAS software, the peak discharge from each rainfall stations for different average recurrence interval (ARI) were calculated. Various non-strctural measures to reduce the impacts of flood are discussed