Journal of Computational Methods in Sciences and Engineering - Volume 19, issue 2

Authors: Zheng, Yan | Li, Yanqi | Li, Wei | Yu, Lei

Article Type: Research Article

Abstract: In this paper, we present a new method for DOA estimation of the admix sources, which is named as Sparse Bayesian Learning for Low-rank and Sparse recovery (SBL-LSR). Considering the low-rank property of the stationary source and the sparsity property of the moving source over the multiple snapshots, SBL-LSR transforms DOA estimation of admix sources over all snapshots into recovering low-rank and sparse matrix from observation matrix. SBL-LSR is developed in the framework of sparse Bayesian learning, which provide the presetting piror of the parameter to be estimated. According to numerical simulations, SBL-LSR shows a superior performance on estimating admix …sources and maintains high precision even under noisy perturbation. Show more

Keywords: Direction-of-arrival, compressive robust principal component analysis, sparse Bayesian learning for low-rank and sparse recovery

DOI: 10.3233/JCM-180855

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 407-416, 2019

Authors: Akimova, Elena N. | Misilov, Vladimir E.

Article Type: Research Article

Abstract: The paper is devoted to developing the new and memory-efficient parallel algorithms based on the nonlinear conjugate gradient method. The algorithms are aimed to solving the nonlinear inverse potential problem of finding a boundary surface between two layers with constant densities. The algorithms utilize the structure of the Jacobian matrix of integral operator by excluding the less significant elements. The efficient implementation for multicore CPU was developed. Investigation of efficiency and speedup of the parallel algorithm was performed. A model problem with synthetic gravitational data was solved. It was shown that the new algorithms reduce the computation time in comparison …with the unmodified one. Show more

Keywords: Potential theory, inverse problem, nonlinear conjugate gradient method, band matrix, parallel algorithmPACS: 02.60.Nm 93.85.Hj 07.05.Tp 89.20.Ff

DOI: 10.3233/JCM-190025

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 417-424, 2019

Article Type: Other

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 425-, 2019

Authors: Tan, Juan Juan | Gu, Feng Long

Article Type: Research Article

Abstract: A new type of metallophthalocyanine/metallofullerene complex, ZnPc/Li@C 60 , is proposed and characterized by using density functional theory. This donor-acceptor complex shows better thermal stability owing to the π –π stacking interaction between ZnPc and Li@C 60 subunits, and the large vertical ionization energy (VIE) is able to force this complex stacked into the desired form. The long range interaction and intramolecular charge transfer indicate that this kind of complex may exhibit excellent first hyperpolarizability. The calculated static hyperpolarizability (β 0 ) of ZnPc/Li@C 60 …shows large value in the range of 11.64 ∼ 32.05 × 10 - 30  esu. This means that metallophthalocyanine/metallofullerene hybrids have great potential for the design and preparation of materials science and will stimulate more extensive studies on the donor-acceptor complexes. Show more

Keywords: Density function theory, charge tranfer, nonlinear optics

DOI: 10.3233/JCM-181001

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 427-439, 2019

Article Type: Other

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 441-, 2019

Article Type: Other

DOI: 10.3233/JCM-181003

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 443-445, 2019

Authors: Saad, N.A. | Zakaria, N.A. | Aziz, H.A. | Abdullah, M.Z. | Zuber, M.

Article Type: Research Article

Abstract: The developed CFD-based model has been used to study the velocity profiles of OBS. The model is very useful tool in view of the fact that the OBS is having complicated hydraulic patterns that always cause a high internal recycle flow or the cycling of mixed liquor throughout the system. The developed CFD model has also been used to assess the current operational performance that is related to aerations shaft of the OBS. To date, limited information is available on the use of CFD simulation for operational performance study. The CFD analysis performed in the research may enhance the use …of CFD in this field. The CFD application in wastewater industries has expanded and the confidence level of using it has also increased. This research has also lead to more studies related to this field. All pros and cons of this research can be used as the guideline for a better CFD application in the related research. When further understanding is achieved in CFD-based process modelling, anyone working in this related field may possibly accomplish a better knowledge or experience to put forward possible development in the CFD models themselves. Show more

Keywords: Aeration device, CFD, orbal biological system, velocity profiles

DOI: 10.3233/JCM-181145

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 447-454, 2019

Authors: Siti Rohani, M.Y. | Syazarina, S.O. | Hamzaini, A.H.

Article Type: Research Article

Abstract: Objective: The aim of this study was to evaluate the role of diffusion-weighted imaging (DWI) and Apparent Diffusion Coefficient (ADC) MRI techniques in the detection and localization of prostate carcinoma in Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM). Materials and Methods: DWI (b value = 800 s/mm) 2 and ADC at 3T were evaluated retrospectively in 78 male patients with suspicion of prostate cancer. The prostate MRI was evaluated after dividing each prostate gland into 6 sections (n = 462). Six sections were excluded …as biopsy result came back as unsatisfactory. Minimum ADC values of each section in the peripheral zone were measured. The MRI finding was compared with biopsy result obtained from each section. Results: The mean minimum ADC values of malignant sextants were significantly lower than that of noncancerous tissue, with a significant negative correlation between the ADC value and the Gleason score. The sensitivity and specificity for DWI + ADC were 52.14% and 93.48% respectively. There is significant difference between malignant and benign ADC value (p = 0.0000). The area under the receiver operating characteristic curve for the detection and localization of prostate cancer within the peripheral zone is 0.788 for ADC, which represents a fair to good test. The cut off ADC value between benign and malignant tissue is 1174.5 mm 2 /s at 93.48% specificity. Conclusion: The current DWI and ADC technique used in our center is very specific and is valuable in detecting, localizing, grading prostate carcinoma and guiding targeted biopsy, with areas of lowest ADC values can indicate the regions to be biopsied. Show more

Keywords: DWI, MRI, ADC, prostate carcinoma

DOI: 10.3233/JCM-181002

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 455-463, 2019

Authors: Kumar, Nitesh | Khader, Abdul | Pai, Raghuvir | Kyriacou, Panayiotis | Khan, Sanowar | Koteshwara, Prakashini

Article Type: Research Article

Abstract: Pulsatile blood flow through the human carotid artery is studied using Computational Fluid Dynamics (CFD) in order to investigate the effect of blood rheology on the hemodynamic parameters. The carotid artery model used is segmented and reconstructed from the Magnetic Resonance Images (MRI) of a specific patient. The results of a non-Newtonian (Carreau-Yasuda) model and a Newtonian model are studied and compared. The results are represented for each peak systole where it is observed that there is significant variation in the spatial parameters between the two models considered in the study. Comparison of local shear stress magnitude in different branches …namely Common Carotid Artery (CCA), Internal Carotid Artery (ICA) and External Carotid Artery (ECA) show that the shear thinning property of blood influences the Wall Shear Stress (WSS) variation. This is observed in branches where there is reduction in diameter and where the diameter reduces due to plaque deposition and also in the region where there is flow recirculation like carotid sinus. Show more

Keywords: Carotid artery, computational fluid dynamic, Newtonian and Carreau-Yasuda, wall shear stress

DOI: 10.3233/JCM-181004

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 465-477, 2019

Authors: Pawlak, Z. | Pai, R. | Mrela, A. | Kaczmarek, M. | Yusuf, K.Q. | Urbaniak, W.

Article Type: Research Article

Abstract: In healthy joints, the cartilage surface coated with phospholipid multi-bilayers is governed by the lamellar-repulsive hydration mechanism. The phospholipid bilayers of biological surface are investigated by friction testing, while surface degradation is controlled by wettability. This paper proposes the presence of cartilage surfaces that are negatively charged results in highly efficient lubrication in natural joints. At pH ∼ 7.4, the mechanism of lamellar-repulsion between contacting cartilage surfaces is supported by charged macromolecules of synovial fluid and phospholipid lamellar phases. It was proven experimentally that phospholipid (PLs) bilayers with lamellar structure can act as an effective solid lubricant in …friction and wear under biological test conditions. Show more

Keywords: Fixed charge density, friction coefficient, lamellar-repulsive hydration lubrication, wettability of synovial joint

DOI: 10.3233/JCM-181104

Citation: Journal of Computational Methods in Sciences and Engineering, vol. 19, no. 2, pp. 479-489, 2019