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      • KCI등재

        Hyper-heuristic algorithm for traffic flow-based vehicle routing problem with simultaneous delivery and pickup

        Wang Zhengwei,Liu Jinlong,Zhang Jingling 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6

        To address the realistic problem of seriously reducing distribution efficiency and increasing distribution cost caused by road traffic congestion, this paper constructs a time-dependent speed describing vehicle travel speed and road traffic flow by simulating the change of urban traffic flow, to establish a vehicle route problem model considering traffic flow with distribution cost and customer satisfaction as optimization objectives. To solve this problem, a hyper-heuristic algorithm based on tabu search is designed in this paper, in which the underlying search operator is selected more efficiently by a high-level heuristic strategy. In addition, the correctness of the model and the effectiveness of the algorithm are verified by conducting simulation experiments on several benchmark sets. Experiment results are shown as the travel speed of the vehicle increases, the average customer satisfaction in lc1-type instances increases to 0.94. And the impact of urban traffic changes on logistics costs and customer satisfaction is further analyzed.

      • Machine learning-based prediction and performance study of transparent soil properties

        Bo Wang,Hengjun Hou,Zhengwei Zhu,Wang Xiao 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.2

        An indispensable process of geotechnical modeling with transparent soils involves analyzing images and soil property simulations. This study proposes an objective framework for quantitative analysis of the influential mechanism of three key factors, namely, different aggregate proportions (DAP), solvent ratio (SR), and solute solution ratio (SSR) on transparent soils’ transparency and shear strength. 125 groups of transparent soil samples considering these three factors were prepared to investigate their impact on transparency and shear strength through Elastic Net regression. Spearman correlation analysis was performed for transparency and shear strength. Furthermore, by comparing the performance of XGBoost, GBDT, Random Forest, and SVR after hyperparameter tuning in predicting transparency and shear strength, XGBoost proved to be the optimal machine learning model with the lowest MSE of 0.0048 and 0.0306 and was innovatively adopted to analyze how various factors affect the transparency and shear strength, thus enhancing the interpretability of machine learning. A ranking system, according to the importance scores of XGBoost, shows that SSR was the most important factor affecting both shear strength and transparency of transparent soils, with importance scores being 0.45 and 0.57, respectively. Our study may shed light on the preparation and performance study of transparent soils.

      • KCI등재

        False Data Injection Attack Detection and Improved WLS Power System State Estimation Based on Node Trust

        Qu Zhengwei,Zhang Jianxuan,Wang Yunjing,Georgievitch Popov Maxim,Guo Kai 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

        To solve the problem that the false data injection attack can evade the unfavorable data recognition mechanism and tamper with the state estimation, this paper proposes a detection and defense scheme for the fake data injecting attack based on the trust degree of the nodes. Considering the failure of the attacker’ s carefully constructed implicit data injection attack with residual threshold method, this paper proposes a node trust model and a trust update algorithm based on the characteristics of state estimation of power system nodes. Feasibility of detecting false data injection based on trustworthiness and using IEEE-14 and IEEEE-118 nodes to systematically analyze diff erent false information injection scenarios. Secondly, in order to eliminate the interference of the false data injected by the attacker to the normal operation of power network, this paper combines the process of trust updating algorithm with the classical weighted least square algorithm to improve the robustness of state estimation and to mitigate the infl uence of fake data injection attacks on power networks. In this paper, simulation experiments are carried out on 14 nodes and 118 nodes system to test the accuracy of the optimized state estimation algorithm

      • Study on the size reduction factor of extreme wind pressure of facade cladding of high-rise buildings with square section

        Xiang Wang,Yong Quan,Zhengwei Zhang,Ming Gu 한국풍공학회 2023 Wind and Structures, An International Journal (WAS Vol.36 No.1

        The effect of cladding panel size on the size reduction factor (SRF) of extreme area-averaging wind pressure (EAWP) on the facades of a high-rise building is often ignored in previous studies. Based on wind tunnel tests, this study investigated the horizontal and vertical correlations of wind pressure on the facade claddings of square-section high-rise buildings. Then, the influencing parameters on the SRF of the EAWP on the cladding panels were analyzed, which were the panel area, panel width, panel length and building width. The results show clear regional distinctions in the correlation of wind pressures on the building facades and the rules of the horizontal and vertical correlations are remarkably different, which causes the cladding size ratio to impact the SRF significantly. Therefore, this study suggests the use of the non-dimensional comprehensive size parameter − / ( is the fitting parameter) determined by the cladding panel horizontal size b, cladding panel vertical size h and the building width B rather than the cladding panel area to describe the variation of the EAWP. Finally, some empirical formula for the SRF of the EAWP on the cladding of a high-rise building is proposed with the nondimensional comprehensive size parameter.

      • KCI등재

        Study on flow characteristics in LBE-cooled main coolant pump under positive rotating condition

        Lu Yonggang,Wang Zhengwei,Zhu Rongsheng,Wang Xiuli,Long Yun 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7

        The Generation IV Lead-cooled fast reactor (LFR) take the liquid lead or lead-bismuth eutectic alloy (LBE) as the coolant of the primary cooling circuit. Combined with the natural characteristics of lead alloy and the design features of LFR, the system is the simplest and the number of equipment is the least, which reflects the inherent safety characteristics of LFR. The nuclear main coolant pump (MCP) is the only power component and the only rotating component in the primary circuit of the reactor, so the various operating characteristics of the MCP are directly related to the safety of the nuclear reactor. In this paper, various working conditions that may occur in the normal rotation (positive rotating) of the MCP and the corresponding internal flow characteristics are analyzed and studied, including the normal pump condition, the positive-flow braking condition and the negative-flow braking condition. Since the corrosiveness of LBE is proportional to the fluid velocity, the distribution of flow velocity in the pump channel will be the focus of this study. It is found that under the normal pump condition and positive-flow braking conditions, the high velocity region of the impeller domain appears at the inlet and outlet of the blade. At the same radius, the pressure surface is lower than the back surface, and with the increase of flow rate, the flow separation phenomenon is obvious, and the turbulent kinetic energy distribution in impeller and diffuser domain shows obvious near-wall property. Under the negative-flow braking condition, there is obvious flow separation in the impeller channel.

      • KCI등재후보

        Comparison study of the effect of bridge-tunnel transition on train aerodynamic performance with or without crosswind

        Lei Zhou,Tanghong Liu,Zhengwei Chen,Wenhui Li,Zijian Guo,Xuhui He,You-Wu Wang 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.6

        This paper studied the case of high-speed train running from flat ground to bridges and into/out of tunnels, with or without crosswind based on the Computational Fluid Dynamics (CFD) method. First, the flow structure was analyzed to explain the influence mechanisms of different infrastructures on the aerodynamic characteristics of the train. Then, the evolution of aerodynamic forces of the train during the entire process was analyzed and compared. Additionally, the pressure variation on the train body and the tunnel wall was examined in detail. The results showed that the pressure coefficient and the flow structure on both sides of the high-speed train were symmetrical for no crosswind case. By contrast, under crosswind, there was a tremendous and immediate change in the pressure mapping and flow structure when the train passing through the bridge-tunnel section. The influence of the ground-bridge transition on the aerodynamic forces was much smaller than that of the bridge-tunnel section. Moreover, the variation of aerodynamic load during the process of entering and exiting the bridge-tunnel sections was both significant. In addition, in the case without crosswind, the change in the pressure change in the tunnel conformed to the law of pressure wave propagation, while under crosswind, the variation in pressure was comprehensively affected by both the train and crosswind in the tunnel.

      • KCI등재

        Target Recognition Triggered Split DNAzyme based Colorimetric Assay for Direct and Sensitive Methicillin-Resistance Analysis of Staphylococcus aureus

        Xu Jin,Jin Dandan,Wang Zhengwei 한국미생물·생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.6

        The accurate and rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) holds significant clinical importance. This work presents a new method for detecting methicillin-resistant Staphylococcus aureus (S. aureus) in clinical samples. The method uses an aptamer-based colorimetric assay that combines a recognizing probe to identify the target and split DNAzyme to amplify the signal, resulting in a highly sensitive and direct analysis of methicillin-resistance. The identification of the PBP2a protein on the membrane of S. aureus in clinical samples leads to the allosterism of the recognizing probe, and thus provides a template for the proximity ligation of split DNAzyme. The proximity ligation of split DNAzyme forms an intact DNAzyme to identify the loop section in the L probe and generates a nicking site to release the loop sequence (“3” and “4” fragments). The “3” and “4” fragments forms an intact sequence to induce the catalytic hairpin assembly, exposing the G-rich section. The released the G-rich sequence of LR probe induces the formation of G-quadruplex–hemin DNAzyme as a colorimetric signal readout. The absorption intensity demonstrated a strong linear association with the logarithm of the S. aureus concentration across a wide range of 5 orders of magnitude dynamic range under the optimized experimental parameters. The limit of detection was calculated to be 23 CFU/ml and the method showed high selectivity for MRSA.

      • KCI등재

        Study of a New Imaging Strategy Based on Compressed Sensing to Shorten the Imaging Time of a Fourier Telescope

        Lei Dong,Zhenwu Lu,Xinyue Liu,Zhengwei Li,Liang Wang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.12

        A Fourier telescope (FT) is an imaging system based on laser illumination and optical aperture synthesis and is suitable for imaging distant targets with high resolution through the atmosphere. The imaging time of a conventional FT is so long (about two hours) as to limit its practical applications. In order to shorten the imaging time of a Fourier telescope, we propose a new imaging system called the compressed sensing Fourier telescope (CS-FT). The image quality, the imaging time and the effects of noise of the new system are studied in detail. Based on the analysis, we find that by reasonably choosing the total sampling rate (TSR), the imaging time of the CS-FT is obviously shorter than that of the conventional FT while the image quality of the CS-FT is near that of the conventional FT. Worth noting is that with the smaller values of the low-frequency sampling rate (LSR) and the order of the sampling probability density function (OPDF), the CS-FT can achieve a better image quality. The reconstruction results of the field data show that the CS-FT can reduce the imaging time of a FT in an actual noise environment.

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