8,434 research outputs found

    Joint Data compression and Computation offloading in Hierarchical Fog-Cloud Systems

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    Data compression has the potential to significantly improve the computation offloading performance in hierarchical fog-cloud systems. However, it remains unknown how to optimally determine the compression ratio jointly with the computation offloading decisions and the resource allocation. This joint optimization problem is studied in the current paper where we aim to minimize the maximum weighted energy and service delay cost (WEDC) of all users. First, we consider a scenario where data compression is performed only at the mobile users. We prove that the optimal offloading decisions have a threshold structure. Moreover, a novel three-step approach employing convexification techniques is developed to optimize the compression ratios and the resource allocation. Then, we address the more general design where data compression is performed at both the mobile users and the fog server. We propose three efficient algorithms to overcome the strong coupling between the offloading decisions and resource allocation. We show that the proposed optimal algorithm for data compression at only the mobile users can reduce the WEDC by a few hundred percent compared to computation offloading strategies that do not leverage data compression or use sub-optimal optimization approaches. Besides, the proposed algorithms for additional data compression at the fog server can further reduce the WEDC

    Multisource power splitting energy harvesting relaying network in half-duplex system over block Rayleigh fading channel: System performance analysis

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    Energy harvesting and information transferring simultaneously by radio frequency (RF) is considered as the novel solution for green-energy wireless communications. From that point of view, the system performance (SP) analysis of multisource power splitting (PS) energy harvesting (EH) relaying network (RN) over block Rayleigh-fading channels is presented and investigated. We investigate the system in both delay-tolerant transmission (DTT), and delay-limited transmission (DLT) modes and devices work in the half-duplex (HD) system. In this model system, the closed-form (CF) expressions for the outage probability (OP), system throughput (ST) in DLT mode and for ergodic capacity (EC) for DTT mode are analyzed and derived, respectively. Furthermore, CF expression for the symbol errors ratio (SER) is demonstrated. Then, the optimal PS factor is investigated. Finally, a Monte Carlo simulation is used for validating the analytical expressions concerning with all system parameters (SP).Web of Science81art. no. 6

    Energy harvesting based two-way full-duplex relaying network over a Rician fading environment: performance analysis

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    Full-duplex transmission is a promising technique to enhance the capacity of communication systems. In this paper, we propose and investigate the system performance of an energy harvesting based two-way full-duplex relaying network over a Rician fading environment. Firstly, we analyse and demonstrate the analytical expressions of the achievable throughput, outage probability, optimal time switching factor, and symbol error ratio of the proposed system. In the second step, the effect of various parameters of the system on its performance is presented and investigated. In the final step, the analytical results are also demonstrated by Monte Carlo simulation. The numerical results proved that the analytical results and the simulation results agreed with each other.Web of Science68112311

    The effect of metal corrosion on the structural reliability of the Pre-Engineered steel frame

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    Nowadays, Pre-Engineered steel buildings are widely used in the field of the industrial construction. However, design standards often only care about the safety (or reliability) at the start time but not concerned about the deterioration of reliability during used under the metal corrosive of environment. Meanwhile, reliability and durability of steel structure depend heavily on metal corrosion of environmental, this is uncertainty parameters. In this research presents the effect of the safety of Pre-Engineered steel frames considering metal corrosion. The metal corrosion modeling used to propose by M.E. Komp. Reliability of the structure is evaluated using Monte Carlo simulation method and Finite Element Method (FEM). This computer program is written by using the MATLAB programming language. The results numbers are reliability and durability behaviors under corrosion are determined for exposure about from 10 - 50 years. Effects of input parameters are also investigated

    FROM THE VIEWPOINT “WU-WEI” OF TAOISM TO THE VIEWPOINT “NHÀN” (LEISURE) OF NGUYEN BINH KHIEM

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    Nguyen Binh Khiem (1491 - 1585), a great thinker of Vietnam in the sixteenth century, contributed to the history of Vietnamese thought with many valuable ideas, including the “Nhàn” (leisure) viewpoint. The thought “Nhàn” (leisure) was originated from Vietnamese social characteristics in the sixteenth century and inherited values in the traditions of national culture and the quintessence of human culture, especially under the profound and clear influence of ideology on human life of Taoism and Lao Tzu. Lao Tzu argued that human beings could not interfere with the evolution of all things and they had to be “wu-wei” in accordance to the rule – “Tao” (faith) to adapt to the objective development of nature and society. Through the method of historical and logical research, analysis and synthesis, the authors found that, from the viewpoint of “wu-wei” of Taoism, Nguyen Binh Khiem proposed a very profound and idyllic “Nhàn” (leisure) viewpoint to deal with the fluctuations of social history at that time through two issues, namely the thought on the category “Nhàn” (leisure) and the content of the category “Nhàn” (leisure) through human beings’ relations with nature and dealing with themselves. His “Nhàn” (leisure) viewpoint, due to objective and subjective circumstances, could not overcome the limitations of the times. However, in the current historical and social conditions, if we know how to inherit the values and overcome limitations, the “Nhàn” (leisure) viewpoint still has modern meanings.  Article visualizations

    Application of the Fenton-like agent based on magnetic iron and manganese oxide in the degradation process of paracetamol in water

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    A Fenton-like catalyst MnO2-Fe3O4/SiO2 is synthesized via a two-step approach. The prepared composite has a mesoporous structure and a high surface area of 190 m2/g. The XRD pattern describes a specific peak of Fe3O4 magnetite on the baseline of amorphous silica. Furthermore, the FTIR spectra not only show the height assigned to stretching vibrations of Si-O-Si bonds, and Fe–O–Fe connections but also exhibit a small peak that matches the Mn–O bonds. SEM images exhibit a porous network structure of the composites with some holes among 30 – 100 nm clusters. The activity of the catalyst is determined in a paracetamol degradation as a Fenton oxidation. The paracetamol removal efficiency is at 85.6% with the optimal condition as initial pH 3, catalyst dosage of 0.15 g/50mL and H2O2 concentration of 1 mL/50 mL. In addition, the catalyst can be reused at least 5 times with a low reduction of the catalytic activity from 85.6% to 80.8%. The experiment results open a direction that has high efficiency in the treatment process of excess paracetamol in pharmacy wastewater

    Application of the Fenton-like agent based on magnetic iron and manganese oxide in the degradation process of paracetamol in water

    Get PDF
    A Fenton-like catalyst MnO2-Fe3O4/SiO2 is synthesized via a two-step approach. The prepared composite has a mesoporous structure and a high surface area of 190 m2/g. The XRD pattern describes a specific peak of Fe3O4 magnetite on the baseline of amorphous silica. Furthermore, the FTIR spectra not only show the height assigned to stretching vibrations of Si-O-Si bonds, and Fe–O–Fe connections but also exhibit a small peak that matches the Mn–O bonds. SEM images exhibit a porous network structure of the composites with some holes among 30 – 100 nm clusters. The activity of the catalyst is determined in a paracetamol degradation as a Fenton oxidation. The paracetamol removal efficiency is at 85.6% with the optimal condition as initial pH 3, catalyst dosage of 0.15 g/50mL and H2O2 concentration of 1 mL/50 mL. In addition, the catalyst can be reused at least 5 times with a low reduction of the catalytic activity from 85.6% to 80.8%. The experiment results open a direction that has high efficiency in the treatment process of excess paracetamol in pharmacy wastewater

    Power beacon-assisted energy harvesting in a half-duplex communication network under co-channel interference over a Rayleigh fading environment: Energy efficiency and outage probability analysis

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    In this time, energy efficiency (EE), measured in bits per Watt, has been considered as an important emerging metric in energy-constrained wireless communication networks because of their energy shortage. In this paper, we investigate power beacon assisted (PB) energy harvesting (EH) in half-duplex (HD) communication network under co-channel Interferer over Rayleigh fading environment. In this work, we investigate the model system with the time switching (TS) protocol. Firstly, the exact and asymptotic form expressions of the outage probability (OP) are analyzed and derived. Then the system EE is investigated and the influence of the primary system parameters on the system performance. Finally, we verify the correctness of the analytical expressions using Monte Carlo simulation. Finally, we can state that the simulation and analytical results are the same.Web of Science1213art. no. 257

    A metal atmosphere corrosion in the industrial zones - Reliability and durability prediction models of steel structures

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    Currently, the steel structure has been popularly used in industrial zones due to cost advantage and fast construction time. However, the industrial zone is an area with complex corrosive agents in the environment such as sulfur dioxides and chlorides. This paper presents a reliability prediction model considering atmosphere corrosion at the industrial zones. The prediction model is a combination of metal atmosphere corrosion (MAC), finite element method (FEM), and Monte Carlo (MC) simulation. Thereafter, that predictive model is applied for reliability and durability assessment of the steel structures due to atmosphere corrosion in the industrial zones until a life-service of 100 years. The result reveals that the safe probability of the steel structure is reduced to approximately 90 and 80% after 50 years and 100 years, respectively. It implies that the time-varying structural degradation at the design step should be considered
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