491 research outputs found
Underdetermined blind source separation based on Fuzzy C-Means and Semi-Nonnegative Matrix Factorization
Conventional blind source separation is based on over-determined with more sensors than sources but the underdetermined is a challenging case and more convenient to actual situation. Non-negative Matrix Factorization (NMF) has been widely applied to Blind Source Separation (BSS) problems. However, the separation results are sensitive to the initialization of parameters of NMF. Avoiding the subjectivity of choosing parameters, we used the Fuzzy C-Means (FCM) clustering technique to estimate the mixing matrix and to reduce the requirement for sparsity. Also, decreasing the constraints is regarded in this paper by using Semi-NMF. In this paper we propose a new two-step algorithm in order to solve the underdetermined blind source separation. We show how to combine the FCM clustering technique with the gradient-based NMF with the multi-layer technique. The simulation results show that our proposed algorithm can separate the source signals with high signal-to-noise ratio and quite low cost time compared with some algorithms
Applied Geological Studies of Some Sinai, Egypt Ore Deposits to Utilized as Extender Pigments for Paint Manufacture
In this present study an investigation is carried out to search for the appropriate local substitutes for the imported paint pigments, samples collected from North, Central and South Sinai includes white sand, coal, quartz, kaolin, gypsum, limestone, chalk. The collected specimens were crushed and ground to powder varying in size between “5-50 um” for testing using laboratory mill. Several laboratory tests were accomplished to identify and evaluate the decorative and protective paint pigment including specific gravity, moisture content, pH value, oil absorption, x-Ray analysis, microscopic studies and others to prove that the selected local ores possess the required characteristics for pigments that can be utilized in producing the paint material in Egypt. The study indicates that the following local ores can be utilized as extender pigments to produce paint materials “calcium carbonate of south Sinai, white sand of Um Bogma, and gypsum of Ras Malaab. The estimated reserves of the studded ores give an indication of presence the sufficient quantities for stream production of the some paint pigments needed for Egyptian market. Key words: Field geology; Paint pigment; Extender pigment; Microscopic studies; X-ray analysis; Chemical analysis; Sinai; Egyp
Unsteady Mixed Convection Flow in the Stagnation Region of a Heated Vertical Plate Embedded in a Variable Porosity Medium with Thermal Dispersion Effects
Trust-based secure clustering in WSN-based intelligent transportation systems
Increasing the number of vehicles on roads leads to congestion and safety problems. Wireless Sensor Network (WSN) is a promising technology providing Intelligent Transportation Systems (ITS) to address these problems. Usually, WSN-based applications, including ITS ones, incur high communication overhead to support efficient connectivity and communication activities. In the ITS environment, clustering would help in addressing the high communication overhead problem. In this paper, we introduce a bio-inspired and trust-based cluster head selection approach for WSN adopted in ITS applications. A trust model is designed and used to compute a trust level for each node and the Bat Optimization Algorithm (BOA) is used to select the cluster heads based on three parameters: residual energy, trust value and the number of neighbors. The simulation results showed that our proposed model is energy efficient (i.e., its power consumption is more efficient than many well-known clustering algorithm such as LEACH, SEP, and DEEC under homogeneous and heterogeneous networks). In addition, the results demonstrated that our proposed model achieved longer network lifetime, i.e., nodes are kept alive longer than what LEACH, SEP and DEEC can achieve. Moreover, the the proposed model showed that the average trust value of selected Cluster Head (CH) is high under different percentage (30% and 50%) of malicious nodes
Mineral Changes in the Blood of Ovariectomized Mice after Treatment with β-Sitosterol
Peer Reviewe
Energija vezanja donora u paraboličkoj kvantnoj jami
We solved the impurity problem in a parabolic quantum well. The binding energy of a neutral donor in GaAs-Alx Ga1!xAs parabolic quantum well is determined variationally. For a dopant at the well center, and at the edge of the well in the interface region, the changes in the binding energy of donors are calculated, for different well sizes and depths. The 2s excited state is reported.Riješili smo problem primjese u paraboličkoj kvantnoj jami. Energija vezanja neutralnog donora u GaAs-Alx Ga1−xAs paraboličkoj kvantnoj jami se rješava varijacijski. Izračunali smo energije vezanja donora ako je u sredini jame i ako je uz rub u međusloju, za različite širine i dubine jame. Izvješćujemo o uzbuđenom stanju 2s
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