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The H∞ Robust Stability and Performance Conditions for Uncertain Robot Manipulators

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 270-272页

作者： Geun Il Song hae Yeon Park jung Hoon Kim the Department of Electrical Engineering Pohang University of Science and Technology (POSTECH) the Department of Electrical Engineering Pohang University of Science and Technology (POSTECH) the Institute for Convergence Research and Education in Advanced Technology Yonsei University

Dear Editor,H∞This letter develops a new framework for the robust stability and performance conditions as well as the relevant controller synthesis with respect to uncertain robot *** often exist model uncertainties between the nominal model and the real robot manipulator and disturbances. Hence, dealing with their effects plays a crucial role in leading to high tracking performances, as discussed in [1]–[5].

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Enhancing Building Facade Image Segmentation via Object-Wise Processing and Cascade U-Net

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Computers, Materials & Continua 2024年第11期81卷 2261-2279页

作者： haemin jung Heesung Park hae Sun jung Kwangyon Lee Department of Industrial&Management Engineering Korea National University of TransportationChungju27469Republic of Korea Department of Industrial Engineering Yonsei UniversitySeoul03722Republic of Korea Department of Applied Artificial Intelligence Sungkyunkwan UniversitySeoul03063Republic of Korea School of Electronic Engineering Soongsil UniversitySeoul06978Republic of Korea

The growing demand for energy-efficient solutions has led to increased interest in analyzing building facades,as buildings contribute significantly to energy consumption in urban ***,conventional image segmentation methods often struggle to capture fine details such as edges and contours,limiting their effectiveness in identifying areas prone to energy *** address this challenge,we propose a novel segmentation methodology that combines object-wise processing with a two-stage deep learning model,Cascade ***-wise processing isolates components of the facade,such as walls and windows,for independent analysis,while Cascade U-Net incorporates contour information to enhance segmentation *** methodology involves four steps:object isolation,which crops and adjusts the image based on bounding boxes;contour extraction,which derives contours;image segmentation,which modifies and reuses contours as guide data in Cascade U-Net to segment areas;and segmentation synthesis,which integrates the results obtained for each object to produce the final segmentation *** to a dataset of Korean building images,the proposed method significantly outperformed traditional models,demonstrating improved accuracy and the ability to preserve critical structural ***,we applied this approach to classify window thermal loss in real-world scenarios using infrared images,showing its potential to identify windows vulnerable to energy ***,our Cascade U-Net,which builds upon the relatively lightweight U-Net architecture,also exhibited strong performance,reinforcing the practical value of this *** approach offers a practical solution for enhancing energy efficiency in buildings by providing more precise segmentation results.

关键词： Building facade image image segmentation edge detection

Discovering High-Quality Threaded Discussions in Online Forums

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Journal of Computer Science & Technology 2014年第3期29卷 519-531页

作者： jung-Tae Lee Min-Chul Yang hae-Chang Rim Department of Computer and Radio Communications Engineering Korea UniversitySeoul 136-713Korea

Archives of threaded discussions generated by users in online forums and discussion boards contain valuable knowledge on various topics. However, not all threads are useful because of deliberate abuses, such as trolling and flaming, that are commonly observed in online conversations. The existence of various users with different levels of expertise also makes it difficult to assume that every discussion thread stored online contains high-quality contents. Although finding high-quality threads automatically can help both users and search engines sift through a huge amount of thread archives and make use of these potentially useful resources effectively, no previous work to our knowledge has performed a study on such task. In this paper, we propose an automatic method for distinguishing high-quality threads from low-quality ones in online discussion sites. We first suggest four different artificial measures for inducing overall quality of a thread based on ratings of its posts. We then propose two tasks involving prediction of thread quality without using post rating information. We adopt a popular machine learning framework to solve the two prediction tasks. Experimental results on a real world forum archive demonstrate that our method can significantly improve the prediction performance across all four measures of thread quality on both tasks. We also compare how different types of features derived from various aspects of threads contribute to the overall performance and investigate key features that play a crucial role in discovering high-quality threads in online discussion sites.

关键词： online forum discussion board thread quality

Comparison of contrast sensitivity based on the surgical results for intermittent exotropia

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International Journal of Ophthalmology(English edition) 2019年第11期12卷 1725-1730页

作者： hae Rang Kim Soo jung Lee Department of Ophthalmology Haeundae Paik Hospital Inje University College of Medicine

AIM: To compare contrast sensitivity(CS) based on the surgical results for intermittent exotropia(IXT) and to examine the relationship between CS and ***: Medical records of the patients who underwent bilateral lateral rectus muscle recession for IXT between 4 and 12 years old were reviewed retrospectively. They were categorized based on the surgical results;successful correction group(n=36) and overcorrection group(esotropia ≥10 PD at 3 mo postoperatively, n=18). Using CGT-2000 test for CS was performed binocularly, and subjective reports of photophobia was investigated preoperatively and at 3 mo postoperatively. Objective photophobia was defined as a significant decrease in CS in the presence of ***: Preoperatively, there was no difference in CS between the groups. Postoperatively, under mesopic conditions, significant improvement of CS was observed at 6.3°, 4°, and 2.5° in the successful correction group and at 6.3° and 4° in the overcorrection group, regardless of glare. Under photopic conditions, at all visual angles except 0.64°, improvement in CS was noted in both groups while CS worsened significantly at 0.64° in the overcorrection group postoperatively. At all visual angles under photopic conditions postoperatively, regardless of glare, CS in the overcorrected group was significantly worse than that in the successful correction group, and CS was significantly decreased by addition of glare in both groups. All patients except one(96.4%) in the successful correction group and 8 patients(61.5%) in overcorrection group showed improvement of photophobia postoperatively, which correlated with CS under photopic conditions(P=0.001, 0.03).CONCLUSION: After surgery for IXT, CS under photopic conditions improve at all visual angles except 0.64°, while CS is significantly worse in the overcorrection group postoperatively at 0.64°. Subjective photophobia havesignificant correlation with CS under photopic conditions, and may be used as an object

关键词： contrast sensitivity intermittent exotropia overcorrection photophobia success

Effects of PWHT on Microstructure and Mechanical Properties of Weld Metals of Ni-Based Superalloy 617 and 263 for Hyper-Supercritical Power Plants

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Acta Metallurgica Sinica(English Letters) 2016年第12期29卷 1107-1118页

作者： Jeong Kil Kim hae ji Park Deog Nam Shim Doosan Heavy Industries and Construction ChangwonGeongnam Korea

It is well known that solid solution-strengthened alloy 617 and γ′ precipitation-strengthened alloy 263 have excellent mechanical properties and corrosion resistance at high temperatures. Hyper-supercritical power plants work at temperatures above 700 ℃, and these superalloys are considered candidate materials for steam turbines components of these power plants. In this study, gas tungsten arc weldability of these superalloys was evaluated, and the effects of post- weld heat treatment （PWHT） on the microstructural characteristics and the mechanical properties of their weld metals were investigated. Scanning transmission electron microscopy, energy-dispersive spectroscopy and electron probe microanalysis were utilized for the investigation. The experimental results confirmed that these weld metals had different characteristics in microstructure and mechanical properties. PWHT resulted in the precipitation of intergranular carbides, γ′ particles and an increase in tensile strength of these superalloy weld metals. Furthermore, fine γ′ particles, which were not detected in the as-welded metal of alloy 263, were precipitated after PWHT and those particles were the reason for the drastic increase in tensile strength.

关键词： Superalloy Welding Precipitation Segregation

Synthesis of Fe_3O_4-coated silica aerogel nanocomposites

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中国有色金属学会会刊：英文版 2012年第S3期22卷 702-706页

作者： Jun Sung LEE Eun jung LEE hae jin HWANG Devision of Materials Science and Engineering Inha University

Fe3O4:SiO2 nanocomposite powders were synthesized by a two-step process,which included the precipitation of FeCl2 and FeCl3 and the gelation of silicic acid solution derived from water *** first,Fe3O4 nanoparticles having a crystallite size of 20 nm were obtained by controlling the ratio of Fe(II) and Fe(III) *** the second step,Fe3O4 particles were embedded in SiO2 matrix by the hydrolysis and subsequent condensation of the silicic acid solution containing Fe3O4 *** was found that the Fe3O4 nanoparticles homogenously disperse in the SiO2 *** Fe3O4:SiO2 nanocomposite exhibited an enhanced thermal stability against oxidation compared with pure ***-IR analysis indicates the presence of the Si-O-Fe bond in the Fe3O4:SiO2 (1:10,mole fraction) nanocomposite.

关键词： nanocomposite Fe3O4 SiO2 sol gel synthesis

Dually-functionalized Ni-rich layered oxides for high-capacity lithium-ion batteries

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Journal of Materials Science & Technology 2021年第27期86卷 70-76页

作者： ji Won Kim Kwangeun jung Taeeun Yim Department of Chemistry Incheon National University119 Academy-roYeonsu-guIncheon 22012Republic of Korea

Layered lithium nickel-cobalt-manganese oxides(NCM)have been highlighted as advanced cathode materials for lithium-ion batteries(LIBs);however,their low interfacial stability must be overcome to ensure stable cycling performance of the *** this work,we propose a one-step surface modification method that uses a task-specific precursor,N,N,N,N-tetraethylsulfamide(NTESA),to improve interfacial stability of Ni-rich NCM cathode *** unstable surface properties of Ni-rich NCM cathode material are improved by embedding an artificial cathode-electrolyte interphase(CEI)layer on the cathode surface by heat treatment of the Ni-rich NCM cathode material with an NTESA precursor at low *** material analyses indicate that this approach allows the formation of amine-and sulfone-functionalized CEI layers on the surface of Ni-rich NCM cathode material without changing the layered structure of the cathode ***-functionalized Ni-rich NCM cathode materials exhibit improved cycling retention after 100 cycles:for example,a cell cycled with a 3.0 NTESA-modified NCM811 cathode presents the highest retention ratio of 88.3%,whereas a cell cycled with a non-functionalized NCM811 cathode suffers from rapid fading of the cycling performance(68.4%).Our additional SEM,XPS,and EIS analyses indicate that electrolyte decomposition is suppressed during electrochemical cycling,thereby leading to smaller increases in the internal ***-MS analyses of the cycled anodes also indicate that the NTESA-based artificial CEI layer inhibits the dissolution of transition metal components from the Ni-rich NCM cathode materials,thereby contributing to an improved overall electrochemical performance of the cell.

关键词： Lithium-ion battery Cathode Cathode-electrolyte interphase N,N,N,N-Tetraethylsulfamide Electrochemical performance

Influence of the preparation method on the catalytic activity of Mg-Al hydrotalcites as solid base catalysts

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Green Energy & Environment 2019年第3期4卷 287-292页

作者： Sungjae Park Dahye Kwon ji Yeon Kang ji Chul jung Department of Chemical Engineering Myongji University

Mg-Al hydrotalcites were synthesized using different preparation methods(a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The method strongly affected the structure of their layers(e.g., the growth and stacking of the layers, and the type of intercalated anions) and, accordingly, their catalytic activity. The Mg-Al hydrotalcite prepared by co-precipitation showed the best catalytic performance in the isomerization of glucose into fructose, due to the small crystallite size and sand rose morphology enhancing the exposure of surface active sites to reactants.

关键词： Mg-Al hydrotalcite Preparation method Base catalyst Glucose isomerization Fructose

Tuning the base properties of Mg–Al hydrotalcite catalysts using their memory effect

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Journal of Energy Chemistry 2020年第7期29卷 229-236,I0008页

作者： Dahye Kwon ji Yeon Kang Suna An Inchan Yang ji Chul jung Department of Chemical Engineering Myongji UniversityYongin 17058Republic of Korea

Herein,the relationship between the structure and base properties of Mg–Al hydrotalcite catalysts was comprehensively investigated in relation to heat treatment and rehydration processes,which are well known as memory effects of *** structure of Mg–Al hydrotalcites changed from layered double hydroxide(LDH)to mixed metal oxide and subsequently to a spinel structure during heat treatment,and it was returned from mixed metal oxide to a LDH structure by *** on various characterizations,we successfully proposed a detailed mechanism of memory *** also confirmed that the Mg–Al hydrotalcites had weak or strong base sites and that their base properties could be systematically tuned by heat treatment and *** prepared Mg–Al hydrotalcites were applied to a model reaction,isomerization of glucose to fructose,as base *** the catalysts tested,the rehydrated Mg–Al hydrotalcite efficiently produced fructose due to its appropriate base and structure *** finally concluded that the base sites of Mg–Al hydrotalcites can be designed as desired by heat treatment and ***,through systematic design of the base sites of Mg–Al hydrotalcites,these can be promising catalysts for various heterogeneous reactions over base catalysts,giving excellent catalytic performances.

关键词： Mg–Al hydrotalcite Structure Base properties Heat treatment Rehydration