5,661 research outputs found

    Enhanced Parallel Hash Function Algorithm Based on 3C Construction (EPHFA-3C)

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    The hash function is a function that can convert data from variable size to fixed-size data that can be used in security of communication like, authentication, digital signature and integration. In this paper, a parallel, secure and fast hash function algorithm that is based on 3C construction is proposed. It is an enhancement for the MD construction. This enhancement makes the construction more resistant to the extension and multi-blocks attacks. The parallel structure of the algorithm improves the speed of hashing and reduces the number of operations. The simulation analysis such as hashes distribution, confusion and diffusion properties, and collision resistance are executed. Based on the results, our proposed hash algorithm is efficient, simple, and has strong security compared with some recent hash algorithms

    Bearing Capacity of Defective Reinforced Concrete Pile in Sand-model Study

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    Concrete piles that were poorly constructed or analyzed in their soil analyses may have structural or geotechnical defects. To examine such defects, an experimental study was conducted to investigate how a defective reinforced concrete pile behaved. These piles were installed and subjected to a compression axial load in the sand that had relative densities of 30%,60%, and 80%. The tests were performed using four concrete model piles: one intact pile and the other three piles had a structural defect (necking) at three different positions of the pile at (0.25 L from the top, center, and 0.25 L bottom). Geotechnical defect (soft layer or debris) was studied using Styrofoam layer at various vertical distances under the pile toe with Y/D = (0, 0.5, 1 and 1.5) D. The test results showed that the bearing capacity of the structural defect was the most in the case of a neck at 0.25 L from the bottom, followed by a neck at the center, and finally a neck at 0.25 L from the top. In the case of a geotechnical defect, the bearing capacity of the pile decreased with the decrease of the vertical distance between the soft layer and the pile toe

    Response of primiparous and multiparous buffaloes to yeast culture supplementation during early and mid-lactation

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    Strains of live Saccharomyces cerevisiae yeast have exhibited probiotic effects in ruminants. This study investigated the effects of the dietary yeast supplement, S. cerevisiae (Yea-Sacc1026), on primiparous (PP) and multiparous (MP) Egyptian buffaloes in early to mid-lactation. Lactating buffaloes were fed either a basal total mixed ration (TMR, control; 4 PP and 8 MP) or the basal TMR plus 10 g Yea-Sacc1026 per buffalo cow per day (yeast; 4 PP and 8 MP). The feeds were given from 15 days prepartum to 180 days postpartum. Feed intake, body weight, and milk yields (MY) were recorded, and milk and blood samples were collected for analyses. Feces were collected from days 45 to 47 during early lactation and from days 90 to 92 during mid-lactation to determine apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and crude fiber (CF). Energy corrected milk yield (ECM), feed conversion, and energy and nitrogen conversion efficiency were calculated. Yeast treated MP buffaloes consumed more DM (P ≤ 0.041) and CP than the untreated control group. Apparent digestibility of DM and OM were significantly greater at mid-lactation for treated versus control group (P = 0.001). Crude fiber digestibility was greater in MP than in PP buffaloes (P = 0.049), and yeast supplemented MP cows had a greater CF digestibility than control MP buffaloes at mid-lactation (P = 0.010). Total blood lipids decreased after yeast supplementation (P = 0.029). Milk yields, ECM, fat and protein yields increased for yeast treated MP buffaloes (P ≤ 0.039). The study concluded that the response to yeast supplementation in buffalo cows is parity dependent. Multiparous buffaloes respond to yeast supplementation with an increased DM intake and CF digestibility without significant weight gains, allowing a greater ECM yield with less fat mobilization. Supplementing buffaloes with yeast culture may increase milk production in early lactation and results in a more persistent milk production during mid-lactation. Feed conversion and energy and nitrogen conversion efficiency may be increased with the use of yeast supplementation in Egyptian buffaloes

    BER Performance Enhancement of MIMO Systems Using Hybrid Detection Techniques Based on Sphere Decoding

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    MIMO system is used in new communication systems to improve the bit error rate (BER), capacity, and the co-channel interference. In this paper, new hybrid detection techniques based on a combination between the sphere decoder (SD) and linear/non-linear detection techniques such as zero forcing (ZF), minimum mean square error (MMSE), Vertical Bell Lab Layered Space Time (V-BLAST), and lattice reduction are introduced. These hybrid techniques are intended to improve the BER performance of MIMO system. The proposed techniques are mainly based on dividing the received signal matrix into two equal size halves. The first half of the received symbols is detected using the selected linear or non-linear detector and the second half is detected using SD as the first scenario. For the second scenario, the first half of the received symbols is detected using SD and the second half is detected using the selected linear or non-linear detector. Several simulations are carried out to verify the efficiency of the proposed techniques. The simulations results show that the proposed techniques provide better performance than the traditional ones

    BER and Capacity/Spectral Efficiency Enhancement of MIMO Systems Using Digital Antenna Arrays Beamforming

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    Multi-input Multi-output (MIMO) systems are of the most promising ones in the field of wireless communications as they provide high data rates and reduce the bit error rate (BER) using spatial multiplexing (SM) and diversity gain techniques, respectively. The deep review of MIMO systems shows that most of them are based on the utilization of uniform linear antennas (ULA) arrays. For further performance enhancement, a new digital array beamforming technique for linear antenna arrays optimization is introduced for both single-user and multi-user MIMO systems to achieve maximum gain. In our proposed technique, the antenna arrays are implemented for a higher gain by adjusting the feeding and the distance between the antenna elements. The modified mathematical model for our proposed digital array beamforming MIMO system has been derived and merged to the current linear detection techniques such as Maximum Likelihood (ML), Zero Forcing (ZF), and Minimum Mean Square Error (MMSE). The simulation results demonstrated the superiority of our proposed technique over the traditional MIMO systems in terms of BER and spectral efficiency (SE)

    A novel optimized conical antenna array structure for back lobe cancellation of uniform concentric circular antenna arrays

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    In wireless communication systems, the existence of the antenna array back lobe represents a significant source of interference, which causes degradation of the signal-to-interference ratio (SIR), and power loss. In this paper, a novel optimized conical antenna array (O-CONAA) structure is proposed for back lobe cancellation of concentric circular antenna arrays (CCAA). Based on the CAA, It is considered to be made up Of several concentric circular antenna arrays (CCAA) which are placed in the X-Y plane. Firstly a non-optimized CONAA is constructed, by arranging these concentric CAAs with uniform vertical spacing along the Z-axis. Consequently, the CONAA seems to be treated as a combination between uniform CAAs and a linear antenna array (LAA). It has been noted that the CONAA radiation pattern has a back lobe amplitude the same as the main beam amplitude. The O-CONAA structure is suggested as a solution to this problem, which provides back lobe cancellation while maintaining the CONAA pattern characteristics like half power beamwidth (HPBW) side lobe level (SLL). The genetic algorithm(GA) approach is used in the O-CONAA structure to optimize the values of both CONAA inter-element spacing around the perimeter of each circle, and vertical spacing along the Z-axis to generate the desired radiation pattern

    Synthesis, crystal structure and spectroscopic characterization of a new organic bismuthate (III) [C9H28N4][Bi2Cl10].H2O

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    The chemical preparation, crystal structure and spectroscopic characterization of [C9H28N4][Bi2Cl10].H2O have been reported. This compound crystallizes in the monoclinic system in space group P21/c and cell parameters a = 12.2385 (6), b = 17.3062 (7), c = 13.0772 (6) Å, β = 104.475 (5)°, Z = 4 and V = 2681.9 (2) Å3. Its crystal structure has been determined and refined to R = 0.049, using 5848 independent reflections. The atomic arrangement can be described by an alternation of organic and inorganic layers. The inorganic layer built up of [Bi2Cl10]4– bioctahedra arranged in sandwich between the organic layer. The organic groups are interconnected by the water molecules through N-H…O(W) hydrogen bonds to form infinite zig-zag chains spreading along the b-axis. These Chains are themselves interconnected by means of the N–H…Cl hydrogen bonds originating from [Bi2Cl10]4– anions, to form a three-dimensional network. Intermolecular Cl…Cl interactions between adjacent dimeric [Bi2Cl10]4– anions have been observed. The compound was also characterized by FT-IR and Raman spectrscopies

    A novel optimized conical antenna array structure for back lobe cancellation of uniform concentric circular antenna arrays

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    In wireless communication systems, the existence of the antenna array back lobe represents a significant source of interference, which causes degradation of the signal-to-interference ratio (SIR), and power loss. In this paper, a novel optimized conical antenna array (O-CONAA) structure is proposed for back lobe cancellation of concentric circular antenna arrays (CCAA). Based on the CAA, It is considered to be made up Of several concentric circular antenna arrays (CCAA) which are placed in the X-Y plane. Firstly a non-optimized CONAA is constructed, by arranging these concentric CAAs with uniform vertical spacing along the Z-axis. Consequently, the CONAA seems to be treated as a combination between uniform CAAs and a linear antenna array (LAA). It has been noted that the CONAA radiation pattern has a back lobe amplitude the same as the main beam amplitude. The O-CONAA structure is suggested as a solution to this problem, which provides back lobe cancellation while maintaining the CONAA pattern characteristics like half power beamwidth (HPBW) side lobe level (SLL). The genetic algorithm(GA) approach is used in the O-CONAA structure to optimize the values of both CONAA inter-element spacing around the perimeter of each circle, and vertical spacing along the Z-axis to generate the desired radiation pattern

    N-acetylcysteine compared to metformin, improves the expression profile of growth differentiation factor-9 and receptor tyrosine kinase c-kit in the oocytes of patients with polycystic ovarian syndrome

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    Background: Paracrine disruption of growth factors in women with polycystic ovarian syndrome (PCOS) results in production of low quality oocyte, especially following ovulation induction. The aim of this study was to investigate the effects of metformin (MET), N-acetylcysteine (NAC) and their combination on the hormonal levels and expression profile of GDF-9, BMP-15 and c-kit, as hallmarks of oocyte quality, in PCOS patients. Materials and Methods: This prospective randomized, double-blind, placebo controlled trial aims to study the effects of MET, NAC and their combination (MET+NAC) on expression of GDF-9, BMP-15 and c-kit mRNA in oocytes [10 at the germinal vesicle (GV) stage, 10 at the MI stage, and 10 at the MII stage from per group] derived following ovulation induction in PCOS. Treatment was carried out for six weeks, starting on the third day of previous cycle until oocyte aspiration. The expression of GDF9, BMP15 and c-kit were determined by quantitative real time polymerase chain reaction (RT-qPCR) and western blot analysis. Data were analyzed with one-way ANOVA. Results: The follicular fluid (FF) level of c-kit protein significantly decreased in the NAC group compared to the other groups. Significant correlations were observed between the FF soluble c-kit protein with FF volume, androstenedione and estradiol. The GDF-9 expression in unfertilized mature oocytes were significantly higher in the NAC group compared to the other groups (P<0.001). Similar difference was not observed between the MET, NAC+MET and control groups. The c-kit expression in unfertilized mature oocytes were significantly lower in the NAC group compared to the other groups (P<0.001). Similar difference was not observed between the MET, NAC+MET and control groups (Registration number: IRCT201204159476N1). Conclusion: We concluded that NAC can improve the quality of oocytes in PCOS. © 2017, Royan Institute (ACECR). All rights reserved
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