Displaying publications 41 - 60 of 1551 in total

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  1. Fulltext An intelligent decision support system for crop yield prediction using hybrid machine learning algorithms
    Anbananthen KSM, Subbiah S, Chelliah D, Sivakumar P, Somasundaram V, Velshankar KH, et al.
    F1000Res, 2021;10:1143.
    PMID: 34987773 DOI: 10.12688/f1000research.73009.1
    Background: In recent times, digitization is gaining importance in different domains of knowledge such as agriculture, medicine, recommendation platforms, the Internet of Things (IoT), and weather forecasting. In agriculture, crop yield estimation is essential for improving productivity and decision-making processes such as financial market forecasting, and addressing food security issues. The main objective of the article is to predict and improve the accuracy of crop yield forecasting using hybrid machine learning (ML) algorithms. Methods: This article proposes hybrid ML algorithms that use specialized ensembling methods such as stacked generalization, gradient boosting, random forest, and least absolute shrinkage and selection operator (LASSO) regression. Stacked generalization is a new model which learns how to best combine the predictions from two or more models trained on the dataset. To demonstrate the applications of the proposed algorithm, aerial-intel datasets from the github data science repository are used. Results: Based on the experimental results done on the agricultural data, the following observations have been made. The performance of the individual algorithm and hybrid ML algorithms are compared using cross-validation to identify the most promising performers for the agricultural dataset.  The accuracy of random forest regressor, gradient boosted tree regression, and stacked generalization ensemble methods are 87.71%, 86.98%, and 88.89% respectively. Conclusions: The proposed stacked generalization ML algorithm statistically outperforms with an accuracy of 88.89% and hence demonstrates that the proposed approach is an effective algorithm for predicting crop yield. The system also gives fast and accurate responses to the farmers.
    Matched MeSH terms: Algorithms*
  2. Image collection and annotation platforms to establish a multi-source database of oral lesions
    Rajendran S, Lim JH, Yogalingam K, Kallarakkal TG, Zain RB, Jayasinghe RD, et al.
    Oral Dis, 2023 Jul;29(5):2230-2238.
    PMID: 35398971 DOI: 10.1111/odi.14206
    OBJECTIVE: To describe the development of a platform for image collection and annotation that resulted in a multi-sourced international image dataset of oral lesions to facilitate the development of automated lesion classification algorithms.

    MATERIALS AND METHODS: We developed a web-interface, hosted on a web server to collect oral lesions images from international partners. Further, we developed a customised annotation tool, also a web-interface for systematic annotation of images to build a rich clinically labelled dataset. We evaluated the sensitivities comparing referral decisions through the annotation process with the clinical diagnosis of the lesions.

    RESULTS: The image repository hosts 2474 images of oral lesions consisting of oral cancer, oral potentially malignant disorders and other oral lesions that were collected through MeMoSA® UPLOAD. Eight-hundred images were annotated by seven oral medicine specialists on MeMoSA® ANNOTATE, to mark the lesion and to collect clinical labels. The sensitivity in referral decision for all lesions that required a referral for cancer management/surveillance was moderate to high depending on the type of lesion (64.3%-100%).

    CONCLUSION: This is the first description of a database with clinically labelled oral lesions. This database could accelerate the improvement of AI algorithms that can promote the early detection of high-risk oral lesions.

    Matched MeSH terms: Algorithms*
  3. Fulltext The global convergence of spectral RMIL conjugate gradient method for unconstrained optimization with applications to robotic model and image recovery
    Salihu N, Kumam P, Awwal AM, Sulaiman IM, Seangwattana T
    PLoS One, 2023;18(3):e0281250.
    PMID: 36928212 DOI: 10.1371/journal.pone.0281250
    In 2012, Rivaie et al. introduced RMIL conjugate gradient (CG) method which is globally convergent under the exact line search. Later, Dai (2016) pointed out abnormality in the convergence result and thus, imposed certain restricted RMIL CG parameter as a remedy. In this paper, we suggest an efficient RMIL spectral CG method. The remarkable feature of this method is that, the convergence result is free from additional condition usually imposed on RMIL. Subsequently, the search direction is sufficiently descent independent of any line search technique. Thus, numerical experiments on some set of benchmark problems indicate that the method is promising and efficient. Furthermore, the efficiency of the proposed method is demonstrated on applications arising from arm robotic model and image restoration problems.
    Matched MeSH terms: Algorithms*
  4. Fulltext Credit card fraud detection using a hierarchical behavior-knowledge space model
    Nandi AK, Randhawa KK, Chua HS, Seera M, Lim CP
    PLoS One, 2022;17(1):e0260579.
    PMID: 35051184 DOI: 10.1371/journal.pone.0260579
    With the advancement in machine learning, researchers continue to devise and implement effective intelligent methods for fraud detection in the financial sector. Indeed, credit card fraud leads to billions of dollars in losses for merchants every year. In this paper, a multi-classifier framework is designed to address the challenges of credit card fraud detections. An ensemble model with multiple machine learning classification algorithms is designed, in which the Behavior-Knowledge Space (BKS) is leveraged to combine the predictions from multiple classifiers. To ascertain the effectiveness of the developed ensemble model, publicly available data sets as well as real financial records are employed for performance evaluations. Through statistical tests, the results positively indicate the effectiveness of the developed model as compared with the commonly used majority voting method for combination of predictions from multiple classifiers in tackling noisy data classification as well as credit card fraud detection problems.
    Matched MeSH terms: Algorithms*
  5. Fulltext Design of agricultural wireless sensor network node optimization method based on improved data fusion algorithm
    Ruipeng T, Jianbu Y, Jianrui T, Aridas NK, Talip MSA
    PLoS One, 2024;19(11):e0308845.
    PMID: 39509355 DOI: 10.1371/journal.pone.0308845
    The agricultural WSN (wireless sensor network) has the characteristics of long operation cycle and wide coverage area. In order to cover as much area as possible, farms usually deploy multiple monitoring devices in different locations of the same area. Due to different types of equipment, monitoring data will vary greatly, and too many monitoring nodes also reduce the efficiency of the network. Although there have been some studies on data fusion algorithms, they have problems such as ignoring the dynamic changes of time series, weak anti-interference ability, and poor processing of data fluctuations. So in this study, a data fusion algorithm for optimal node tracking in agricultural wireless sensor networks is designed. By introducing the dynamic bending distance in the dynamic time warping algorithm to replace the absolute distance in the fuzzy association algorithm and combine the sensor's own reliability and association degree as the weighted fusion weight, which improved the fuzzy association algorithm. Finally, another three algorithm were tested for multi-temperature sensor data fusion. Compare with the kalman filter, arithmetic mean and fuzzy association algorithm, the average value of the improved data fusion algorithm is 29.5703, which is close to the average value of the other three algorithms, indicating that the data distribution is more even. Its extremely bad value is 8.9767, which is 10.04%, 1.14% and 9.85% smaller than the other three algorithms, indicating that it is more robust when dealing with outliers. Its variance is 2.6438, which is 2.82%, 0.65% and 0.27% smaller than the other three algorithms, indicating that it is more stable and has less data volatility. The results show that the algorithm proposed in this study has higher fusion accuracy and better robustness, which can obtain the fusion value that truly feedbacks the agricultural environment conditions. It reduces production costs by reducing redundant monitoring devices, the energy consumption and improves the data collection efficiency in wireless sensor networks.
    Matched MeSH terms: Algorithms*
  6. Fulltext A Hybrid SSA and SMA with Mutation Opposition-Based Learning for Constrained Engineering Problems
    Wang S, Liu Q, Liu Y, Jia H, Abualigah L, Zheng R, et al.
    Comput Intell Neurosci, 2021;2021:6379469.
    PMID: 34531910 DOI: 10.1155/2021/6379469
    Based on Salp Swarm Algorithm (SSA) and Slime Mould Algorithm (SMA), a novel hybrid optimization algorithm, named Hybrid Slime Mould Salp Swarm Algorithm (HSMSSA), is proposed to solve constrained engineering problems. SSA can obtain good results in solving some optimization problems. However, it is easy to suffer from local minima and lower density of population. SMA specializes in global exploration and good robustness, but its convergence rate is too slow to find satisfactory solutions efficiently. Thus, in this paper, considering the characteristics and advantages of both the above optimization algorithms, SMA is integrated into the leader position updating equations of SSA, which can share helpful information so that the proposed algorithm can utilize these two algorithms' advantages to enhance global optimization performance. Furthermore, Levy flight is utilized to enhance the exploration ability. It is worth noting that a novel strategy called mutation opposition-based learning is proposed to enhance the performance of the hybrid optimization algorithm on premature convergence avoidance, balance between exploration and exploitation phases, and finding satisfactory global optimum. To evaluate the efficiency of the proposed algorithm, HSMSSA is applied to 23 different benchmark functions of the unimodal and multimodal types. Additionally, five classical constrained engineering problems are utilized to evaluate the proposed technique's practicable abilities. The simulation results show that the HSMSSA method is more competitive and presents more engineering effectiveness for real-world constrained problems than SMA, SSA, and other comparative algorithms. In the end, we also provide some potential areas for future studies such as feature selection and multilevel threshold image segmentation.
    Matched MeSH terms: Algorithms*
  7. Design and real time implementation of single phase boost power factor correction converter
    Bouafassa A, Rahmani L, Mekhilef S
    ISA Trans, 2015 Mar;55:267-74.
    PMID: 25457043 DOI: 10.1016/j.isatra.2014.10.004
    This paper presents a real time implementation of the single-phase power factor correction (PFC) AC-DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations.
    Matched MeSH terms: Algorithms
  8. Fulltext Enhancing the Quality of Service for Real Time Traffic over Optical Burst Switching (OBS) Networks with Ensuring the Fairness for Other Traffics
    Al-Shargabi MA, Shaikh A, Ismail AS
    PLoS One, 2016;11(9):e0161873.
    PMID: 27583557 DOI: 10.1371/journal.pone.0161873
    Optical burst switching (OBS) networks have been attracting much consideration as a promising approach to build the next generation optical Internet. A solution for enhancing the Quality of Service (QoS) for high priority real time traffic over OBS with the fairness among the traffic types is absent in current OBS' QoS schemes. In this paper we present a novel Real Time Quality of Service with Fairness Ratio (RT-QoSFR) scheme that can adapt the burst assembly parameters according to the traffic QoS needs in order to enhance the real time traffic QoS requirements and to ensure the fairness for other traffic. The results show that RT-QoSFR scheme is able to fulfill the real time traffic requirements (end to end delay, and loss rate) ensuring the fairness for other traffics under various conditions such as the type of real time traffic and traffic load. RT-QoSFR can guarantee that the delay of the real time traffic packets does not exceed the maximum packets transfer delay value. Furthermore, it can reduce the real time traffic packets loss, at the same time guarantee the fairness for non real time traffic packets by determining the ratio of real time traffic inside the burst to be 50-60%, 30-40%, and 10-20% for high, normal, and low traffic loads respectively.
    Matched MeSH terms: Algorithms
  9. Fulltext A Hermite interpolated LUT for RF power amplifiers
    Dinaagaren Selvadurai, Roslina M. Sidek, Khalid Al-Hussaini, Borhanuddin M. Ali
    Pertanika Journal of Science & Technology, 2017;25(102):299-306.
    MyJurnal
    Digital predistortion is one of the most widely used techniques to linearize a power amplifier (PA) to
    reduce the error vector magnitude (EVM) distortion and spectral regrowth. By far, the lookup table (LUT) predistorters are most frequently used scheme to mitigate the effects of non-linear power amplifier. In this paper, a new algorithm of joint-polynominal LUT predistorter which attains the best linearization performance is proposed. The algorithm employs the hermite interpolation LUT, which has a higher accuracy of interpolation. Simulation results show that the proposed method provides a better rejection of EVM distortion and an improvement of 30-40% of adjacent channel leakage ratio (ACLR) for the wideband code division multiple access at a minimal memory usage.
    Matched MeSH terms: Algorithms
  10. One-step exponential-rational methods for the numerical solution of first order initial value problems
    Teh YY, Nazeeruddin Yaacob
    Sains Malaysiana, 2013;42:845-853.
    In this study, a new class of exponential-rational methods (ERMs) for the numerical solution of first order initial value problems has been developed. Developments of third order and fourth order ERMs, as well as their corresponding local truncation error have been presented. Each ERM was found to be consistent with the differential equation and L-stable. Numerical experiments showed that the third order and fourth order ERMs generates more accurate numerical results compared with the existing rational methods in solving first order initial value problems.
    Matched MeSH terms: Algorithms
  11. Quintic spline method for solving linear and nonlinear boundary value problems
    Osama Ala’yed, Ying TY, Azizan Saaban
    Sains Malaysiana, 2016;45:1007-1012.
    In this article, a fourth order quintic spline method has been developed to obtain numerical solutions for second order
    boundary value problems with Dirichlet boundary conditions. The developments of the quintic spline method and
    convergence analysis were presented. Three test problems have been considered for comparison purposes. The numerical
    results showed that the quintic spline method is more accurate compared to existing cubic spline method when solving
    nonlinear second order boundary value problems but vice versa when solving linear second order boundary value
    problems.
    Matched MeSH terms: Algorithms
  12. Fulltext Incremental Interval Type-2 Fuzzy Clustering of Data Streams using Single Pass Method
    Qaiyum S, Aziz I, Hasan MH, Khan AI, Almalawi A
    Sensors (Basel), 2020 Jun 05;20(11).
    PMID: 32517018 DOI: 10.3390/s20113210
    Data Streams create new challenges for fuzzy clustering algorithms, specifically Interval Type-2 Fuzzy C-Means (IT2FCM). One problem associated with IT2FCM is that it tends to be sensitive to initialization conditions and therefore, fails to return global optima. This problem has been addressed by optimizing IT2FCM using Ant Colony Optimization approach. However, IT2FCM-ACO obtain clusters for the whole dataset which is not suitable for clustering large streaming datasets that may be coming continuously and evolves with time. Thus, the clusters generated will also evolve with time. Additionally, the incoming data may not be available in memory all at once because of its size. Therefore, to encounter the challenges of a large data stream environment we propose improvising IT2FCM-ACO to generate clusters incrementally. The proposed algorithm produces clusters by determining appropriate cluster centers on a certain percentage of available datasets and then the obtained cluster centroids are combined with new incoming data points to generate another set of cluster centers. The process continues until all the data are scanned. The previous data points are released from memory which reduces time and space complexity. Thus, the proposed incremental method produces data partitions comparable to IT2FCM-ACO. The performance of the proposed method is evaluated on large real-life datasets. The results obtained from several fuzzy cluster validity index measures show the enhanced performance of the proposed method over other clustering algorithms. The proposed algorithm also improves upon the run time and produces excellent speed-ups for all datasets.
    Matched MeSH terms: Algorithms
  13. Fulltext Computational intelligence and metaheuristic algorithms with applications
    Yang XS, Chien SF, Ting TO
    ScientificWorldJournal, 2014;2014:425853.
    PMID: 25610904 DOI: 10.1155/2014/425853
    Matched MeSH terms: Algorithms
  14. Fulltext On Cℵ-fibrations in bitopological semigroups
    Dawood S, Kılıçman A
    ScientificWorldJournal, 2014;2014:675761.
    PMID: 25215328 DOI: 10.1155/2014/675761
    We extend the path lifting property in homotopy theory for topological spaces to bitopological semigroups and we show and prove its role in the C(ℵ)-fibration property. We give and prove the relationship between the C(ℵ)-fibration property and an approximate fibration property. Furthermore, we study the pullback maps for C(ℵ)-fibrations.
    Matched MeSH terms: Algorithms
  15. Fulltext Effects of solder temperature on pin through-hole during wave soldering: thermal-fluid structure interaction analysis
    Aziz MS, Abdullah MZ, Khor CY
    ScientificWorldJournal, 2014;2014:482363.
    PMID: 25225638 DOI: 10.1155/2014/482363
    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183(°)C) < T < 643.15 K (370(°)C). Both solvers were coupled by the real time coupling software and mesh-based parallel code coupling interface during analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT) between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry.
    Matched MeSH terms: Algorithms
  16. Fulltext Heat transfer enhancement of laminar nanofluids flow in a circular tube fitted with parabolic-cut twisted tape inserts
    Salman SD, Kadhum AA, Takriff MS, Mohamad AB
    ScientificWorldJournal, 2014;2014:543231.
    PMID: 24605055 DOI: 10.1155/2014/543231
    Numerical investigation has been carried out on heat transfer and friction factor characteristics of copper-water nanofluid flow in a constant heat-fluxed tube with the existence of new configuration of vortex generator using Computational Fluid Dynamics (CFD) simulation. Two types of swirl flow generator: Classical twisted tape (CTT) and Parabolic-cut twisted tape (PCT) with a different twist ratio (y = 2.93, 3.91 and 4.89) and different cut depth (w = 0.5, 1.0 and 1.5 cm) with 2% and 4% volume concentration of CuO nanofluid were used for simulation. The effect of different parameters such as flow Reynolds number, twist ratio, cut depth and nanofluid were considered. The results show that the enhancement of heat transfer rate and the friction factor induced by the Classical (CTT) and Parabolic-cut (PCT) inserts increases with twist ratio and cut depth decreases. The results also revealed that the heat transfer enhancement increases with an increase in the volume fraction of the CuO nanoparticle. Furthermore, the twisted tape with twist ratio (y = 2.93) and cut depth w = 0.5 cm offered 10% enhancement of the average Nusselt number with significant increases in friction factor than those of Classical twisted tape.
    Matched MeSH terms: Algorithms
  17. Fulltext A ROM-less direct digital frequency synthesizer based on hybrid polynomial approximation
    Omran QK, Islam MT, Misran N, Faruque MR
    ScientificWorldJournal, 2014;2014:812576.
    PMID: 24892092 DOI: 10.1155/2014/812576
    In this paper, a novel design approach for a phase to sinusoid amplitude converter (PSAC) has been investigated. Two segments have been used to approximate the first sine quadrant. A first linear segment is used to fit the region near the zero point, while a second fourth-order parabolic segment is used to approximate the rest of the sine curve. The phase sample, where the polynomial changed, was chosen in such a way as to achieve the maximum spurious free dynamic range (SFDR). The invented direct digital frequency synthesizer (DDFS) has been encoded in VHDL and post simulation was carried out. The synthesized architecture exhibits a promising result of 90 dBc SFDR. The targeted structure is expected to show advantages for perceptible reduction of hardware resources and power consumption as well as high clock speeds.
    Matched MeSH terms: Algorithms
  18. Fulltext Analysis of rattleback chaotic oscillations
    Hanias M, Stavrinides SG, Banerjee S
    ScientificWorldJournal, 2014;2014:569386.
    PMID: 24511290 DOI: 10.1155/2014/569386
    Rattleback is a canoe-shaped object, already known from ancient times, exhibiting a nontrivial rotational behaviour. Although its shape looks symmetric, its kinematic behaviour seems to be asymmetric. When spun in one direction it normally rotates, but when it is spun in the other direction it stops rotating and oscillates until it finally starts rotating in the other direction. It has already been reported that those oscillations demonstrate chaotic characteristics. In this paper, rattleback's chaotic dynamics are studied by applying Kane's model for different sets of (experimentally decided) parameters, which correspond to three different experimental prototypes made of wax, gypsum, and lead-solder. The emerging chaotic behaviour in all three cases has been studied and evaluated by the related time-series analysis and the calculation of the strange attractors' invariant parameters.
    Matched MeSH terms: Algorithms
  19. Fulltext Numerical method using cubic B-spline for a strongly coupled reaction-diffusion system
    Abbas M, Majid AA, Md Ismail AI, Rashid A
    PLoS One, 2014;9(1):e83265.
    PMID: 24427270 DOI: 10.1371/journal.pone.0083265
    In this paper, a numerical method for the solution of a strongly coupled reaction-diffusion system, with suitable initial and Neumann boundary conditions, by using cubic B-spline collocation scheme on a uniform grid is presented. The scheme is based on the usual finite difference scheme to discretize the time derivative while cubic B-spline is used as an interpolation function in the space dimension. The scheme is shown to be unconditionally stable using the von Neumann method. The accuracy of the proposed scheme is demonstrated by applying it on a test problem. The performance of this scheme is shown by computing L∞ and L2 error norms for different time levels. The numerical results are found to be in good agreement with known exact solutions.
    Matched MeSH terms: Algorithms
  20. General form of domination polynomial for two types of graphs associated to dihedral groups
    Nabilah Najmuddin, Nor Haniza Sarmin, Ahmad Erfanian
    MATEMATIKA, 2019;35(2):149-155.
    MyJurnal
    A domination polynomial is a type of graph polynomial in which its coefficients represent the number of dominating sets in the graph. There are many researches being done on the domination polynomial of some common types of graphs but not yet for graphs associated to finite groups. Two types of graphs associated to finite groups are the conjugate graph and the conjugacy class graph. A graph of a group G is called a conjugate graph if the vertices are non-central elements of G and two distinct vertices are adjacent if they are conjugate to each other. Meanwhile, a conjugacy class graph of a group G is a graph in which its vertices are the non-central conjugacy classes of G and two distinct vertices are connected if and only if their class cardinalities are not coprime. The conjugate and conjugacy class graph of dihedral groups can be expressed generally as a union of complete graphs on some vertices. In this paper, the domination polynomials are computed for the conjugate and conjugacy class graphs of the dihedral groups.
    Matched MeSH terms: Algorithms
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