70 research outputs found

    An Airfield Minimum Operating Strip Selection Method Based on the TOPSIS Method

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    With Multiple Attribute Decision Making (MADM) method, the selection of airfield Minimum Operating Strip (MOS) schemes is researched. The influencing factors of the selection decision making are analyzed. The weight values of these factors are determined. Then the decision making optimization method based on TOPSIS is presented. At last, the feasibility of the method is validated with a calculation example

    Reliability Research of Power Distribution System For Important Units at the Airfield

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    Important power units at the airport are the direct units of aviation security, the reliability of power supply and distribution system directly affect the safety of it for aviation security. This paper analyzes the important units of electricity power supply system into the units of reliability. The basic reliability model and the mission reliability model are constructed respectively and the corresponding reliabilities are calculated. Then the paper studies on the relationship between two kinds of reliability as well as the influence on the reliability of power supply and distribution system, providing theoretical basis of planning, equipment selection, engineering design, reliable operation and maintenance management for important units of power supply system

    Effect of matrix suction on the shear strength characteristics of reinforced granite residual soil

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    Introduction: The soil in geogrid-reinforced structures is typically unsaturated, with the shear strength provided by both the matrix suction and the reinforced body. Traditional structural designs for saturated soils only consider the shear strength provided by the reinforced body, neglecting the part provided by matrix suction. As a result, the design for reinforced structures is biased toward conservatism.Method: The study examined the matrix suction-provided shear strength in reinforced soils through strain-controlled triaxial and soil-water characteristic curve (SWCC) pressure plate instrumentation. The feasibility of the Schrefler and Khalili unsaturated soil shear strength formulas for predicting shear strength based on matrix suction forces was verified.Results: The study revealed that the cohesion of saturated reinforced soil exhibits a significant decrease in contrast with unsaturated reinforced soil, with matrix suction serving as a crucial consideration for reinforced structure design.Discussion: The experimental results confirm the suitability of applying the quasi-cohesion increment theory to reinforced clays. The Khalili formula can be utilized to predict the quasi cohesion of unsaturated reinforced soils with greater accuracy under diverse dry density conditions. The results obtained using post-shear moisture content were closer to the measured values than those using initial moisture content

    MPIWiz: subgroup reproducible replay of MPI applications

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    ABSTRACT Message Passing Interface (MPI) is a widely used standard for managing coarse-grained concurrency on distributed computers. Debugging parallel MPI applications, however, has always been a particularly challenging task due to their high degree of concurrent execution and non-deterministic behavior. Deterministic replay is a potentially powerful technique for addressing these challenges, with existing MPI replay tools adopting either data-replay or orderreplay approaches. Unfortunately, each approach has its tradeoffs. Data-replay generates substantial log sizes by recording every communication message. Order-replay generates small logs, but requires all processes to be replayed together. We believe that these drawbacks are the primary reasons that inhibit the wide adoption of deterministic replay as the critical enabler of cyclic debugging of MPI applications. This paper describes subgroup reproducible replay (SRR), a hybrid deterministic replay method that provides the benefits of both data-replay and order-replay while balancing their trade-offs. SRR divides all processes into disjoint groups. It records the contents of messages crossing group boundaries as in data-replay, but records just message orderings for communication within a group as in order-replay. In this way, SRR can exploit the communication locality of traffic patterns in MPI applications. During replay, developers can then replay each group individually. SRR reduces recording overhead by not recording intra-group communication, and at the same time reduces replay overhead by limiting the size of each replay group. Exposing these tradeoffs gives the user the necessary control for making deterministic replay practical for MPI applications. We have implemented a prototype, MPIWiz, to demonstrate and evaluate SRR. MPIWiz employs a replay framework that allows transparent binary instrumentation of both library and system calls. As a result, MPIWiz replays MPI applications with no source code modification and relinking, and handles non-determinism in both MPI and OS system calls. Our preliminary results show that MPIWiz can reduce recording overhead by over a factor of four relative to data-replay, yet without requiring the entire application to be replayed as in order-replay. Recording increases execution time by 27% while the application can be replayed in just 53% of its base execution time

    Assessment of Response to Chemotherapy in Pancreatic Cancer with Liver Metastasis: CT Texture as a Predictive Biomarker

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    In this paper, we assess changes in CT texture of metastatic liver lesions after treatment with chemotherapy in patients with pancreatic cancer and determine if texture parameters correlate with measured time to progression (TTP). This retrospective study included 110 patients with pancreatic cancer with liver metastasis, and mean, entropy, kurtosis, skewness, mean of positive pixels, and standard deviation (SD) values were extracted during texture analysis. Response assessment was also obtained by using RECIST 1.1, Choi and modified Choi criteria, respectively. The correlation of texture parameters and existing assessment criteria with TTP were evaluated using Kaplan-Meier and Cox regression analyses in the training cohort. Kaplan-Meier curves of the proportion of patients without disease progression were significantly different for several texture parameters, and were better than those for RECIST 1.1-, Choi-, and modified Choi-defined response (p < 0.05 vs. p = 0.398, p = 0.142, and p = 0.536, respectively). Cox regression analysis showed that percentage change in SD was an independent predictor of TTP (p = 0.016) and confirmed in the validation cohort (p = 0.019). In conclusion, CT texture parameters have the potential to become predictive imaging biomarkers for response evaluation in pancreatic cancer with liver metastasis

    Liquid-liquid phase separation: Fundamental physical principles, biological implications, and applications in supramolecular materials engineering

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    Liquid-liquid phase separation (LLPS) is a captivating phenomenon in which a uniform mixture spontaneously divides into two liquid phases with differing component concentrations. It is prevalent in soft matter, is observed in systems involving polymers, organic molecules, and proteins, and is influenced by environmental factors and component properties. Recent recognition of LLPS within living organisms reveals its role in creating cellular compartments to orchestrate complex biochemical reactions, requiring distinct boundaries and unhindered molecular movement. Nonmembrane compartments, stemming from cytoplasmic LLPS, such as nucleoli, hold promise for synthetic cell engineering and cellular function insights. Under certain conditions, LLPS is linked to diseases such as sickle-cell disease, cancer, and neurodegenerative diseases. This review offers a concise overview of LLPS in soft matter, emphasizing its relevance in soft material engineering. We delve into fundamental mechanisms, focusing on biological systems, and explore the implications of LLPS, spanning organelles, substance exchange, molecular diffusion, and disease associations. LLPS enables soft material engineering, with applications in biomedicine and bioengineering, shaping future possibilities in bioengineering, from foundational cellular constructs to intricate artificial tissue development

    Optical Labels Enabled Optical Performance Monitoring in WDM Systems

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    Optical performance monitoring (OPM), particularly the optical power and optical signal-to-noise ratio (OSNR) of each wavelength channel, are of great importance and significance and need to be implemented to ensure stable and efficient operation/maintenance of wavelength division multiplexing (WDM) networks. However, the critical monitoring module of existing solutions generally are too expensive, operationally inconvenient and/or functionally limited to apply over WDM systems with numerous nodes. In this paper, a low-cost and high-efficiency OPM scheme based on differential phase shift keying (DPSK)-modulated digital optical labels is proposed and demonstrated. Each pilot tone is modulated by digital surveillance information and treated as an identity indicator and performance predictor that ties up to each wavelength channel and thereby can monitor the performance of all wavelength channels simultaneously by only one low-bandwidth photoelectric detector (PD) and by designed digital signal processing (DSP) algorithms. Simulation results showed that the maximum errors of channel power monitoring and OSNR estimation were both less than 1 dB after 20-span WDM transmission. In addition, offline experiments were also carried out and further verified the feasibility of our OPM scheme. This confirms that the optical label based OPM has lower cost and higher efficiency and thereby is of great potential for mass deployment in practical WDM systems

    Optical Labels Enabled Optical Performance Monitoring in WDM Systems

    No full text
    Optical performance monitoring (OPM), particularly the optical power and optical signal-to-noise ratio (OSNR) of each wavelength channel, are of great importance and significance and need to be implemented to ensure stable and efficient operation/maintenance of wavelength division multiplexing (WDM) networks. However, the critical monitoring module of existing solutions generally are too expensive, operationally inconvenient and/or functionally limited to apply over WDM systems with numerous nodes. In this paper, a low-cost and high-efficiency OPM scheme based on differential phase shift keying (DPSK)-modulated digital optical labels is proposed and demonstrated. Each pilot tone is modulated by digital surveillance information and treated as an identity indicator and performance predictor that ties up to each wavelength channel and thereby can monitor the performance of all wavelength channels simultaneously by only one low-bandwidth photoelectric detector (PD) and by designed digital signal processing (DSP) algorithms. Simulation results showed that the maximum errors of channel power monitoring and OSNR estimation were both less than 1 dB after 20-span WDM transmission. In addition, offline experiments were also carried out and further verified the feasibility of our OPM scheme. This confirms that the optical label based OPM has lower cost and higher efficiency and thereby is of great potential for mass deployment in practical WDM systems

    An Approximate Estimation Approach of Fault Size for Spalled Ball Bearing in Induction Motor by Tracking Multiple Vibration Frequencies in Current

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    Fault size estimation is of great importance to bearing performance degradation assessment and life prediction. Until now, fault size estimation has generally been based on acoustic emission signals or vibration signals; an approach based on current signals has not yet been mentioned. In the present research, an approximate estimation approach based on current is introduced. The proposed approach is easy to implement for existing inverter-driven induction motors without complicated calculations and additional sensors, immune to external disturbances, and suitable for harsh conditions. Firstly, a feature transmission route from spall, to Hertzian forces, and then to friction torque is simulated based on a spall model and dynamic model of the bearing. Based on simulated results, the relation between spall size and the multiple characteristic vibration frequencies in friction torque is revealed. Secondly, the multiple characteristic vibration frequencies modulated in the current is investigated. Analysis results show that those frequencies modulated in the current are independent of each other, without spectrum overlap. Thirdly, to address the issue of which fault features modulated in the current are very weak, a fault-feature-highlighting approach based on reduced voltage frequency ratio is proposed. Finally, experimental tests were conducted. The obtained results validate that the proposed approach is feasible and effective for spall size estimation
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