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Optimized algorithm for balancing clusters in wireless sensor networks

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1404-1412页

作者： Mucheol kim Sunhong kim Hyungjin BYUN School of Computer Science and Engineering Chung-Ang University 221Heuk seok-dongDongjak-guSeoul 156-756Korea

Wireless sensor networks consist of hundreds or thousands of sensor nodes that involve numerous restrictions in-cluding computation capability and battery *** control is an important issue for achieving a balanced placement of sensor *** clustering scheme is a widely known and efficient means of topology control for transmitting information to the base station in two *** automatic routing scheme of the self-organizing technique is another critical element of wireless sensor *** this paper we propose an optimal algorithm with cluster balance taken into consideration,and compare it with three well known and widely used approaches,i.e.,LEACH,MEER,and VAP-E,in performance *** results show that the proposed approach increases the overall network lifetime,indicating that the amount of energy required for com-munication to the base station will be reduced for locating an optimal cluster.

关键词： Wireless sensor networks Self-organizing sensor algorithm Clustering algorithm Optimization

Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by Selective Nucleophilic Substitution of Phosphorus

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Nano-Micro Letters 2024年第10期16卷 618-637页

作者： Se In kim Woong-Ju kim Jin Gu Kang Dong-Wan kim School of Civil Environmental and Architectural EngineeringKorea University02841 SeoulSouth Korea Nanophotonics Research Center Korea Institute of Science and Technology02792 SeoulSouth Korea

Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy ***,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery *** thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal ***,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H *** resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H *** doping concentrations are varied by controlling the amount of precursors or their mean free *** at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 *** improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state *** approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.

关键词： Li-ion battery Two-dimensional N-type siloxene Doping mechanism Kinetics

Computational approaches for fast generation of digital 3D video holograms(Invited Paper)

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Chinese Optics Letters 2009年第12期7卷 1083-1091页

作者： Seung-Cheol kim Eun-Soo kim 3D Display Research Center Department of Electronic Engineering Kwangwoon University

Several approaches for fast generation of digital holograms of a three-dimensional （3D） object have been discussed. Among them, the novel look-up table （N-LUT） method is analyzed to dramatically reduce the number of pre-calculated fringe patterns required for computation of digital holograms of a 3D object by employing a new concept of principal fringe patterns, so that problems of computational complexity and huge memory size of the conventional ray-tracing and look-up table methods have been considerably alleviated. Meanwhile, as the 3D video images have a lot of temporally or spatially redundant data in their inter- and intra-frames, computation time of the 3D video holograms could be also reduced just by removing these redundant data. Thus, a couple of computational methods for generation of 3D video holograms by combined use of the N-LUT method and data compression algorithms are also presented and discussed. Some experimental results finally reveal that by using this approach a great reduction of computation time of 3D video holograms could be achieved.

关键词： LUT Computational approaches for fast generation of digital 3D video holograms CGH

Silicon photonic Bessel-Gaussian beam generation unlocks new possibilities for long-range sensing

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Light(Science & Applications) 2023年第7期12卷 1178-1179页

作者： Sangsik kim School of Electrical Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea

Concentrically distributed silicon photonic grating arrays generate long-range Besse-Gaussian beams,enabling rotational and range measurements over *** compact and mass-producible chip unlocks new potentials for long-... 详细信息

关键词： Gaussian Bessel beam

Mini-review on river eutrophication and bottom improvement techniques, with special emphasis on the Nakdong River

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Journal of Environmental Sciences 2015年第4期27卷 113-121页

作者： Andinet Tekile Ilho kim Jisung kim Department of Construction Environment Engineering University of Science & Technology Korea Institute of Civil Eng. and Building Technology

Water quality in rivers is vital to humans and to maintenance of biotic and ecological *** the Four Major Rivers restoration of South Korea, remarkable attempts have been made to decrease external nutrient loads and moveable weirs were designed to discharge silt that may deposit in pools. However, recently eutrophication of the Nakdong River, which was limited to the lower reaches, is seen to be spreading upstream. The reduction of external nutrient loads to rivers is a long-term goal that is unlikely to lead to reductions in algal blooms for many years because of the time required to implement effective land management strategies. It would therefore be desirable to implement complementary strategies. Regulating the amount of water released is effective at preventing algae blooms in weir pools; so, the relationship between discharge, stratification and bloom formation should be understood in this regard. However, pollutants are likely to accumulate in the riverbed upstream from release points. Thus, to control phosphorus levels, total phosphorus density should be lowered by applying in-river techniques as well. As many ecosystem properties are controlled by multiple processes, simultaneous river bottom improvement techniques, such as combined dissolved oxygen supply and nutrient inactivation, are likely to be effective. The purpose of this review is to present a series of technological approaches that can be used to improve the river bottom area and hence sediment nutrient release, and to illustrate the application of these techniques to the Nakdong River.

关键词： Eutrophication Internal load Nakdong Phosphorus River bottom

Non-Local Analysis of Forming Limits of Ductile Material Considering Void Growth

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Journal of Materials Science & Technology 2003年第4期19卷 294-299页

作者： Youngsuk kim School of Mechanical Engineering Kyungpook National University702-701DaeguSouth Korea

The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.

关键词： Non-local Characteristic length Vbid Damage growth Gradient-dependent plasticity Forming limit Strain localization

Variable selection-based SPC procedures for high-dimensional multistage processes

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Journal of Systems Engineering and Electronics 2019年第1期30卷 144-153页

作者： kim Sangahn Department of Business Analytics and Acturial Science Siena College

Monitoring high-dimensional multistage processes becomes crucial to ensure the quality of the final product in modern industry environments. Few statistical process monitoring(SPC) approaches for monitoring and controlling quality in highdimensional multistage processes are studied. We propose a deviance residual-based multivariate exponentially weighted moving average(MEWMA) control chart with a variable selection procedure. We demonstrate that it outperforms the existing multivariate SPC charts in terms of out-of-control average run length(ARL) for the detection of process mean shift.

关键词： diagnosis procedure deviance residual fault identification model-based control chart multistage process monitoring variable selection.

Mapping of ground motion amplifications for the Fraser River delta in Greater Vancouver, Canada

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Earthquake Engineering and Engineering Vibration 2019年第4期18卷 703-717页

作者： Byungmin kim Ulsan National Institute of Science and Technology

The Fraser River delta in Greater Vancouver, Canada consists of deep soft deposits of silts and clays, and it is well known that the deep soil deposits can amplify the low frequency contents of ground motions. This study aims to investigate the eff ects of deep soil deposits in the delta on ground motion amplifi cations by using thorough site response simulations that account for the full soil profi les and a suite of recorded ground motions that covers a wide range of intensity levels. Based on both equivalent-linear and nonlinear site response simulations, the eff ects of soil depth (represented by natural period of the soil, TS) on ground motion amplifi cations for various spectral periods are clearly demonstrated. The ground motion amplifi cation maps for various spectral periods and rock ground motion intensity levels are also generated to be used in the regional seismic hazard assessment for infrastructure. It is found that ground motions for long periods are substantially amplifi ed in the center of the delta, while those for short periods are de-amplifi ed when input rock motions are large.

关键词： Fraser River delta ground motion amplifi cation deep soil deposits site response analysis basin depth

Suggestion of Maintenance Criteria for Electric Railroad Facilities Based on Fuzzy TOPSIS

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Computers, Materials & Continua 2022年第3期70卷 5453-5466页

作者： Sunwoo Hwang Joouk kim Hagseoung kim Hyungchul kim Youngmin kim Innovative Transportation and Logistics Research Center Korea Railroad Research InstituteUiwang16105Korea Smart Electrical&Signaling Division Korea Railroad Research InstituteUiwang16105Korea Department of Systems Engineering Ajou UniversitySuwon16499Korea

This paper is on the suggestion of maintenance items for electric railway facility *** the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility systems are also increasing,but the railroad electrical facility system in Korea is rapidly *** solve this problem,various methodologies are applied to ensure operational reliability and stability for railroad electrical facility systems,but there is a lack of detailed evaluation criteria for railroad electrical facility system ***,maintenance items must be selected in a scientific and systematic ***,railroad electrical facility systems are selected for *** StructureMatrix(DSM)is utilized to establish considerations tailored to the maintenance characteristics,and the Fuzzy-TOPSIS methodology is utilized for determining the maintenance detail evaluation item baseline weights,a multi-criteria decision-making *** show that degradation,insulation items have the highest weight of 14.63%,and capacity items have the lowest weight of 5.34%.The results of this may be contributed to the underlying research in carrying out maintenance activities to ensure the reliability and safety of railroad electrical facility systems.

关键词： Electrical facility system railroad maintenance fuzzy method