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Spatial analysis of vegetation cover response to climate trends in Khakassia(South Siberia)

Journal of Mountain Science 2023年第10期20卷 2869-2884页

作者： im Sergei Institute of Natural Sciences and Mathematics Khakassian State University named after N.F.KatanovAbakan 655000Russia V.N.Sukachev Institute of Forest Krasnoyarsk Science Centre of the Siberian Branch of Russian Academy of ScienceKrasnoyarsk 660036Russia Institute of Ecology and Geography Siberian Federal UniversityKrasnoyarsk 660041Russia Institute of Space Research and High Technologies Reshetnev Siberian State University of Science and TechnologyKrasnoyarsk660014Russia

An analysis of the changes in vegetation cover on the territory of the Republic of Khakassia in 2000–2021 due to climatic trends was carried out based on the MODIS *** changes in vegetation cover were estimated based on trends in Normalized Difference Vegetation Index(NDVI)and Enhanced Vegetation Index(EVI).In general,in the 21st century,an increase in the biomass of vegetation cover is *** trends were observed in 16%–22%of the territory,and negative only in 1%–3%.For about 20%of the analyzed territory,a significant influence of climate on the changes in vegetation cover was *** most pronounced negative impact on vegetation cover was caused by summer air and soil temperatures,spring temperature,and summer winds,and the positive impact was caused by summer precipitation and soil *** response of the vegetation cover to climate was non-uniform concerning the ***,a significant correlation with the amount of precipitation was observed for~20%–35%of vegetation growing below 600 m above sea level and for less than 5%above this *** negative effect of summer temperatures on plants prevailed mainly at an elevation below~1400 m above sea *** climate change is likely to lead to significant degradation of vegetation in the steppe and foreststeppe in Khakassia in the coming decades.

关键词： Khakassia South Siberia Vegetation cover Climate trends Remote sensing MODIS NDVI EVI Relief

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Stochastic structural optimization using particle swarm optimization, surrogate models and Bayesian statistics

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Chinese Journal of Aeronautics 2013年第1期26卷 112-121页

作者： Jongbin im Jungsun Park Korea Aerospace Research Institute Department of Aerospace and Mechanical Engineering Korea Aerospace University

This paper focuses on a method to solve structural optimization problems using particle swarm optimization （PSO）, surrogate models and Bayesian statistics. PSO is a random/stochastic search algorithm designed to find the global optimum. However, PSO needs many evaluations compared to gradient-based optimization. This means PSO increases the analysis costs of structural optimization. One of the methods to reduce computing costs in stochastic optimization is to use approximation techniques. In this work, surrogate models are used, including the response surface method （RSM） and Kriging. When surrogate models are used, there are some errors between exact values and approximated values. These errors decrease the reliability of the optimum values and discard the realistic approximation of using surrogate models. In this paper, Bayesian statistics is used to obtain more reliable results. To verify and confirm the efficiency of the proposed method using surrogate models and Bayesian statistics for stochastic structural optimization, two numerical examples are optimized, and the optimization of a hub sleeve is demonstrated as a practical problem.

关键词： Bayesian statistics Kriging Particle swarm optimization (PSO) Response surface method (RSM)

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improved rate-distortion optimized video coding using non-integer bit estimation and multiple Lambda search

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Frontiers of Computer Science 2016年第1期10卷 157-166页

作者： Sio Kei im Mohammad Mahdi GHANDI MPI-QMUL Information Systems Research Centre Macao Polytechnic Institute Macao China Department of Electronic Systems Engineering University of Essex Colchestey CO4 3SQ UK

Many modern video encoders use the Lagrangian rate-distortion optimization （RDO） algorithm for mode deci- sions during the compression procedure. For each encoding stage, this approach involves minimizing a cost, which is a function of rate, distortion and a multiplier called Lambda. This paper proposes to improve the RDO process by applying two modifications. The first modification is to increase the ac- curacy of rate estimation, which is achieved by computing a non-integer number of bits for arithmetic coding of the syntax elements. This leads to a more accurate cost computation and therefore a better mode decision. The second modification is to search and adjust the value of Lambda based on the char- acteristics of each coding stage. For the encoder used, this paper proposes to search multiple values of Lambda for the intra-4x4 mode decision. Moreover, a simple shift in Lambda value is proposed for motion estimation. Each of these modi- fications offers a certain gain in RDO performance, and, when all are combined, an average bit-rate saving of up to 7.0% can be achieved for the H.264/AVC codec while the same concept is applicable to the H.265/HEVC codec as well. The extra added complexity is contained to a certain level, and is also adjustable according to the processing resources available.

关键词： rate distortion optimization Lambda adjust-ment non-integer bit estimation H.264/AVC H265/HEVCvideo coding

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Scalable Ir-Doped NiFe₂O₄/TiO₂ Heterojunction Anode for Decentralized Saline Wastewater Treatment and H₂ Production

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NANO-MICRO LETTERS 2025年第1期17卷 1-18页

作者： Hong, Sukhwa Kim, Jiseon Park, Jaebeom im, Sunmi Hoffmann, Michael R. Cho, Kangwoo Pohang Univ Sci & Technol POSTECH Div Environm Sci & Engn Pohang 790784 South Korea CALTECH Linde Labs Pasadena CA 91125 USA Yonsei Univ Int Campus Inst Convergence Res & Educ Adv Technol I CREATE Incheon 21983 South Korea

Wastewater electrolysis cells (WECs) for decentralized wastewater treatment/reuse coupled with H-2 production can reduce the carbon footprint associated with transportation of water, waste, and energy carrier. This study reports Ir-doped NiFe2O4 (NFI, similar to 5 at% Ir) spinel layer with TiO2 overlayer (NFI/TiO2), as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell. In dilute (0.1 M) NaCl solutions, the NFI/TiO2 marks superior activity and selectivity for chlorine evolution reaction, outperforming the benchmark IrO2. Robust operation in near-neutral pH was confirmed. Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO2 which serves both as the primary site for Cl- chemisorption and a protective layer for NFI as an ohmic contact. Galvanostatic electrolysis of NH4+-laden synthetic wastewater demonstrated that NFI/TiO2 not only achieves quasi-stoichiometric NH4+-to-N-2 conversion, but also enhances H-2 generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine. The scaled-up WEC with NFI/TiO2 was demonstrated for electrolysis of toilet wastewater.

关键词： Wastewater electrolysis cell Ir-doped NiFe2O4 Reactive chlorine species Decentralized H-2 production On-site wastewater treatment

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Two-dimensional physical habitat modeling of effects of habitat structures on urban stream restoration

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Water Science and Engineering 2011年第4期4卷 386-395页

作者： Dongkyun im Hyeongsik KANG Water Infrastructure Division Samsung C & T Corporation Seoul 1321-20 Korea Division of Water and Environment Korea Environment Institute Seoul 122-706 Korea

River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was evaluated by a weighted usable area （WUA） using River2D, a two-dimensional hydraulic model. The habitat suitability for Zacco platypus in the Hongje Stream was simulated with and without habitat structures. The computed WUA values for the boulder, spur dike, and riffle increased by about 2%, 7%, and 131%, respectively, after their construction. Also, the three habitat structures, especially the riffle, can contribute to increasing hydraulic heterogeneity and enhancing habitat diversity.

关键词： stream restoration physical habitat River2D weighted usable area

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Time-domain channel estimator based on cyclic correlationfor OFDM systems with guard interval

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The Journal of China Universities of Posts and Telecommunications 2008年第2期15卷 26-31页

作者： im Se-bin CHOI Hyung-jin Communication Research Center Harbin Institute of Technology

Channel impulse response （CIR） can be estimated on the basis of cyclic correlation in time-domain for orthogonal frequency division multiplexing （OFDM） systems, This article proposes a generalized channel estimation method to reduce the estimation error by taking the average of different CIRs. Channel impulse responses are derived according to the different starting points of cyclic correlation. In addition, an effective CIR length estimation algorithm is also presented. The whole proposed methods are more effective to OFDM systems, especialiy to those with longer cyclic prefix. The analysis and the simulation results verify that the mean square error performance is 4-5 dB better than the conventional schemes under the same conditions.

关键词： CIR OFDM channel estimation mean squareerror (MSE)

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Accurate simulation of surfaces and interfaces of ten FCC metals and steel using Lennard–Jones potentials

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npj Computational Materials 2021年第1期7卷 205-219页

作者： Krishan Kanhaiya Seonghan Kim Wonpil im Hendrik Heinz Department of Chemical and Biological Engineering University of Colorado at BoulderBoulderCO 80301USA Departments of Biological Sciences Chemistryand BioengineeringLehigh UniversityBethlehemPA 18015USA

The earlier integration of validated Lennard–Jones(LJ)potentials for 8 fcc metals into materials and biomolecular force fields has advanced multiple research fields,for example,metal–electrolyte interfaces,recognition of biomolecules,colloidal assembly of metal nanostructures,alloys,and *** we introduce 12-6 and 9-6 LJ parameters for classical all-atom simulations of 10 further fcc metals(Ac,Ca(α),Ce(γ),Es(β),Fe(γ),Ir,Rh,Sr(α),Th(α),Yb(β))and stainless *** parameters reproduce lattice constants,surface energies,water interfacial energies,and interactions with(bio)organic molecules in 0.1 to 5%agreement with experiment,as well as qualitative mechanical properties under standard *** are reduced up to a factor of one hundred in comparison to earlier Lennard–Jones parameters,embedded atom models,and density functional *** also explain a quantitative correlation between atomization energies from experiments and surface energies that supports parameter *** models are computationally very efficient and applicable to an exponential space of *** with a wide range of force fields such as the Interface force field(IFF),AMBER,CHARMM,COMPASS,CVFF,DREIDING,OPLS-AA,and PCFF enables reliable simulations of nanostructures up to millions of atoms and microsecond time ***-friendly model building and input generation are available in the CHARMM-GUI Nanomaterial *** a limitation,deviations in mechanical properties vary and are comparable to DFT *** discuss the incorporation of reactivity and features of the electronic structure to expand the range of applications and further increase the accuracy.

关键词： steel metals qualitative

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EFFECT OF RECYCLED CONCRETE AGGREGATE, AIR ENTRAINING ADMIXTURE AND MAXimUM AGGREGATE PARTICLE SIZE ON THE BEHAVIOR OF CONCRETE UNDER FREEZE-THAW CYCLES

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Journal of Green Building 2021年第2期16卷 217-233页

作者： Yeşim Tarhan RemziŞahin Atatürk University Department of Civil EngineeringErzurumTRyesim Atatürk University Engineering FacultyDepartment of Civil EngineeringErzurumTR

This article presents freeze-thaw(F/T)resistance of concrete containing recycled concrete aggregate(RCA).RCA percentages of 15%,30%,45%,and 60%were replaced by natural *** entraining admixture(AEA)with three different ratios(0.06%,0.13%,and 0.20%)were used and three different maximum aggregate particle sizes(dmax=16 mm,22.4 mm and 31.5 mm)were selected.F/T resistances of the concretes were determined through the measurement of scaling on the surfaces of the samples placed in 3%NaCl solution in pursuance of TS CEN/TS *** was observed that the compressive strength of the concretes decreased by 20%on average compared to the control samples with the increase in the amount of ***,it was determined from the experiments that the use of RCA increases the F/T resistances of the concretes as it provides extra voids in the concrete and decreases capillary *** the limits of this study,d_(max)=22.4 mm,RCA=45%and AEA=0.13%are recommended as the optimum values for F/T resistance of the *** is also recommended to use RCA in pavement applications including roadways,highways,parking facilities,and other non-structural concrete elements subjected to severe winter conditions.

关键词： recycled concrete aggregate freeze-thaw resistance concrete pavement NaCl solution

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impact of tibial transverse transport in tissue regeneration and wound healing with perspective on diabetic foot ulcers

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World Journal of Diabetes 2024年第5期15卷 810-813页

作者： Sulagna Mukherjee Seung-Soon im Department of Physiology Keimyung University School of MedicineDaegu 42601Republic of Korea

In this editorial,we comment on an article by Liao et al published in the current issue of the World Journal of *** focus on the clinical significance of tibial transverse transport(TTT)as an effective treatment for patients with diabetic foot ulcers(DFU).TTT has been associated with tissue regeneration,improved blood circulation,reduced amputation rates,and increased expression of early angiogenic ***,TTT can influence macrophage polarization and growth factor *** this potential,the limitations and conflicting results of existing studies justify the need for further research into its optimal application and *** clinical implications highlight the efficacy of TTT in recalcitrant DFU and provide lasting stimuli for tissue re-generation,and blood vessel and bone marrow ***-lation via systemic responses contributes to its therapeutic *** studies should investigate the underlying molecular mechanisms to enhance our understanding and the efficacy of *** manuscript emphasizes the potential of TTT in limb preservation and diabetic wound healing and suggests avenues for preventive measures against limb amputation in diabetes and peripheral artery ***,we highlight the clinical significance of the TTT and its importance in healing DFU to promote the use of this technique in tissue regeneration.

关键词： Diabetes foot ulcer Tibial transverse transport Foot surgery Wound healing Tissue regeneration

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Charge-carrier photogeneration and extraction dynamics of polymer solar cells probed by a transient photocurrent nearby the regime of the space charge-limited current

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Frontiers of Chemical Science and Engineering 2021年第1期15卷 164-179页

作者： Boa Jin Hyunmin Park Yang Liu Leijing Liu Jongdeok An Wenjing Tian Chan im Department of Chemistry Konkuk UniversitySeoul 05029Republic of Korea State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China

To understand the complex behaviors of photogenerated charge carriers within polymer-based bulk-heterojunction-type solar cells,the charge-carrier photogeneration and extraction dynamics are simultaneously estimated using a transient photocurrent technique under various external-bias voltages,and a wide range of excitation intensities are *** this purpose,conventional devices with 80 nm thick active layers consisting of a blend of representative P3HT and PTB7 electron-donating polymers and proper electron-accepting fullerene derivatives were *** the correction for the saturation behavior at a high excitation-intensity range nearby the regime of the space charge-limited current,the incident-photon-density-dependent maximum photocurrent densities at the initial peaks are discussed as the proportional measures of the charge-carrier-photogeneration *** comparing the total number of the extracted charge carriers to the total number of the incident photons and the number of the initially photogenerated charge carriers,the external quantum efficiencies as well as the extraction quantum efficiencies of the charge-carrier collection during a laser-pulse-induced transient photocurrent process were ***,the charge-carrier concentration-dependent mobility values were obtained,and they are discussed in consideration of the additional influences of the charge-carrier losses from the device during the charge-carrier extraction that also affects the photocurrent-trace shape.

关键词： charge-carrier photogeneration transient photocurrent polymer solar cells charge-carrier extraction space charge-limited current

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