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A New Encryption Mechanism Supporting the Update of Encrypted Data for Secure and Efficient Collaboration in the Cloud Environment

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 813-834页

作者： Chanhyeong cho Byeori Kim Haehyun cho Taek-young youn Department of Cyber Security Dankook UniversityYongin16890Republic of Korea Department of Software Soongsil UniversitySeoul07027Republic of Korea

With the rise of remote collaboration,the demand for advanced storage and collaboration tools has rapidly ***,traditional collaboration tools primarily rely on access control,leaving data stored on cloud servers vulnerable due to insufficient *** paper introduces a novel mechanism that encrypts data in‘bundle’units,designed to meet the dual requirements of efficiency and security for frequently updated collaborative *** bundle includes updated information,allowing only the updated portions to be reencrypted when changes *** encryption method proposed in this paper addresses the inefficiencies of traditional encryption modes,such as Cipher Block Chaining(CBC)and Counter(CTR),which require decrypting and re-encrypting the entire dataset whenever updates *** proposed method leverages update-specific information embedded within data bundles and metadata that maps the relationship between these bundles and the plaintext *** utilizing this information,the method accurately identifies the modified portions and applies algorithms to selectively re-encrypt only those *** approach significantly enhances the efficiency of data updates while maintaining high performance,particularly in large-scale data *** validate this approach,we conducted experiments measuring execution time as both the size of the modified data and the total dataset size *** show that the proposed method significantly outperforms CBC and CTR modes in execution speed,with greater performance gains as data size ***,our security evaluation confirms that this method provides robust protection against both passive and active attacks.

关键词： Cloud collaboration mode of operation data update efficiency

Numerical study on the heat dissipation characteristics of high-power LED module

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Science China(Technological Sciences) 2013年第9期56卷 2150-2155页

作者： LEE DaeWoo cho sung-Wook KIM youn-Jea Graduate School of Mechanical Engineering Sungkyunkwan University School of Mechanical Engineering Sungkyunkwan University

LED lighting has problems such as short life span, power reduction due to the LED chip's heat, and decreased luminance efficiency etc. Many studies on the optimization of the thermal performance of LEDs have been conducted actively to solve these problems. The present study changes the fin shape and intervals of various heat sink designs so that LED can effectively produce a thermal effect. The water-cooling heat release system and the heat pipe methods show higher thermal performance results than the existing systems; however, the system is of high cost and requires a large-scale apparatus. This study carried out a numerical analysis of the thermal control system by applying heat flux and heat sink properties as an active heat release system using the commercial code ANSYS ver. 13.0 and verified the validity of the new heat sink design for temperature distribution analysis.

关键词： LED lighting water-cooling heat release system heat loss

Thermodynamic model for deoxidation of liquid steel considering strong metal-oxygen interaction in the quasichemical model framework

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 988-1002页

作者： Yong-Min cho youn-Bae Kang Graduate Institute of Ferrous and Eco Materials Technology Pohang University of Science and TechnologyPohangKyungbuk37673Rep.of Korea N.EX.T Hub POSCO HoldingsPohangKyungbuk37673Rep.of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohangKyungbuk37673Rep.of Korea

Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was *** model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for the minimization of internal Gibbs energy preliminarily when solving deoxidation *** elimination of internal Gibbs energy minimization is particularly advantageous during the coupling of deoxidation equilibrium calculations with computationally intensive approaches,such as computational fluid *** model enables efficient calculations through direct embedment of the explicit forms of activity coefficient in the computing *** proposed thermodynamic model was developed using a quasichemical approach with two key approximations:random mixing of metallic elements(Fe and oxidizing metal) and strong nonrandom pairing of metal and oxygen as nearest *** these approximations,the quasichemical approach yielded the activity coefficients of solutes as explicit functions of composition and temperature without requiring the minimization of internal Gibbs energy or the coupling of separate *** model was successfully applied in the calculation of deoxidation equilibria of various elements(Al,B,C,Ca,Ce,Cr,La,Mg,Mn,Nb,Si,Ti,V,and Zr).The limitations of the model arising from these assumptions were also discussed.

关键词： deoxidation equilibria thermodynamics quasichemical approach computational fluid dynamics

Probabilistic seismic performance assessment of lap-spliced RC columns retrofitted by steel wrapping jackets

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Earthquake Engineering and Engineering Vibration 2016年第2期15卷 223-238页

作者： Eunsoo choi Heejung youn Baik-Soon cho Department of Civil Engineering Hongik University Department of Civil Engineering CTRCInje University

In this study, the seismic fragility curves of two reinforced concrete（RC） columns that were lap-spliced at the bottom and retrofitted with steel wrapping jackets were generated. Their seismic performance was probabilistically assessed in comparison to that of lap-spliced or continuous reinforcement RC columns. This study used two types of steel wrapping jackets, a full jacket and a split jacket. Analytical models of the four types of columns were developed based on the experimental results of the columns using Open SEES, which is effective in conducting nonlinear time history analyses. A suite of ten artificial ground motions, modified from recorded ground motions, was used to perform nonlinear time history analyses of the analytical models with scaling of the peak ground acceleration from 0.1 g to 1.0 g in increments of 0.1 g. The steel wrapping jackets did not increase the medians for yield（slight damage state） of the lap-spiced column and did not exceed the corresponding median of the continuous reinforcement column. However, the two steel jackets increased the medians for failure by 1.872 and 2.017 times, respectively, and exceeded the corresponding median of the continuous reinforcement column by 11.8% and 20.5%, respectively.

关键词： columns reinforcement reinforced exceed acceleration scaling median assessed split probabilistic

Computational discovery of p-type transparent oxide semiconductors using hydrogen descriptor

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npj Computational Materials 2018年第1期4卷 503-509页

作者： Kanghoon Yim Yong youn Miso Lee Dongsun Yoo Joohee Lee sung Haeng cho Seungwu Han Department of Materials Science and Engineering and Research Institute of Advanced Materials Seoul National UniversitySeoul 08826Korea Electronics and Telecommunications Research Institute(ETRI) Daejeon 34129Korea Korea Institute of Energy Research Daejeon 34129Korea

The ultimate transparent electronic devices require complementary and symmetrical pairs of n-type and p-type transparent *** several n-type transparent oxide semiconductors like InGaZnO and ZnO are available and being used in consumer electronics,there are practically no p-type oxides that are comparable to the n-type counterpart in spite of tremendous efforts to discover ***,high-throughput screening with the density functional theory calculations attempted to identify candidate p-type transparent oxides,but none of suggested materials was verified experimentally,implying need for a better theoretical ***,we propose a highly reliable and computationally efficient descriptor for p-type dopability—the hydrogen impurity *** show that the hydrogen descriptor can distinguish well-known p-type and n-type *** the hydrogen descriptor,we screen most binary oxides and a selected pool of ternary compounds that covers Sn^(2+)-bearing and Cu^(1+)-bearing oxides as well as *** a result,we suggest La_(2)O_(2)Te and CuLiO as promising p-type oxides.

关键词： transparent semiconductors oxide

Treatment and prognosis of hepatic epithelioid hemangioendothelioma based on SEER data analysis from 1973 to 2014

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Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 29-35页

作者： O Kyu Noh Soon Sun Kim Min Jae Yang Sun Gyo Lim Jae Chul Hwang Hyo Jung cho Jae youn Cheong sung Won cho Department of Radiation Oncology Ajou University School of MedicineSuwonKorea Department of Biomedical Informatics Ajou University School of MedicineSuwonKorea Office of Biostatistics Ajou Research Institute for Innovative MedicineAjou University Medical CenterSuwonKorea Department of Gastroenterology Ajou University School of MedicineSuwonKorea

Background: Hepatic epithelioid hemangioendothelioma (HEH) is a rare tumor of vascular origin with an unknown etiology, a low incidence, and a variable natural course. We evaluated the management and prognosis of HEH from the Surveillance, Epidemiology and End Results (SEER) program and changes in treatment modalities of HEH over 30 years. Methods: From 1973 to 2014 in the SEER database, we selected patients diagnosed with HEH. We analyzed the clinical characteristics, patterns of management, and clinical outcomes of patients with HEH. Results: We identi ed 79 patients with HEH (median age: 54.0 years;male to female ratio: 1:2.6). The initial extent of disease was local in 22 (27.8%) patients, regional metastasis in 22 (27.8%), distant metas-tasis in 31 (39.2%) and unknown in 4 (5.1%). The median size of primary tumor was 3.85 cm (interquartile range, 2.50 7.93 cm). Among 74 patients with available management data, the most common manage-ment was no treatment (29/74, 39.2%), followed by chemotherapy only (22/74, 29.7%), liver resection-based (13/74, 17.6%), and transplantation-based therapy (6/74, 8.1%). The 5-year cancer-speci c survival rate was 57.8%. Patients who underwent surgical treatment had signi cantly higher survival than those who underwent non-surgical treatment (5-year survival;88% vs. 49%, P=0.019). Multivariate analysis revealed that surgical therapy was the only independent prognostic factor for survival (hazard ratio: 0.20, P=0.040). Conclusions: Resection or liver transplantation is worth considering for treatment of patients with HEH.

关键词： Hemangioendothelioma Epithelioid SEER program Liver transplantation Hepatectomy Liver neoplasms

Newly-modeled graphene-based ternary nanocomposite for the magnetophotocatalytic reduction of CO_(2) with electrochemical performance

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Frontiers of Chemical Science and Engineering 2022年第10期16卷 1438-1459页

作者： Zambaga Otgonbayar Kwang youn cho chong-Hun Jung Won-Chun Oh Department of Advanced Materials Science&Engineering Hanseo UniversitySeosan-Si 31962Korea Korea Institutes of Ceramic Engineering and Technology Jinju-Si 660031Korea Decommissioning Technology Research Division Korea Atomic Energy Research InstituteDaejeon 305-600Korea Anhui International Joint Research Center for Nano Carbon-based Materials and Environmental Health College of Materials Science and EngineeringAnhui University of Science&TechnologyHuainan 232001China

The development of CO_(2)into hydrocarbon fuels has emerged as a green method that could help mitigate global *** novel structured photocatalyst is a promising material for use in a photocatalytic and magneto-electrochemical method that fosters the reduction of CO_(2)by suppressing the recombination of electron−hole pairs and effectively transferring the electrons to the surface for the chemical reaction of CO_(2)*** our study,we have developed a novel-structured AgCuZnS_(2)–graphene–TiO_(2)to analyze its catalytic activity toward the selective evolution of CO_(2).The selectivity of each nanocomposite substantially enhanced the activity of the AgCuZnS_(2)–graphene–TiO_(2)ternary nanocomposite due to the successful interaction,and the selectivity of the final product was improved to a value 3 times higher than that of the pure AgCuZnS_(2)and 2 times higher than those of AgCuZnS_(2)–graphene and AgCuZnS_(2)–TiO_(2)under ultraviolet(UV)-light(λ=254 nm)irradiation in the photocatalytic *** electrochemical CO_(2)reduction test was also conducted to analyze the efficacy of the AgCuZnS_(2)–graphene–TiO_(2)when used as a working electrode in laboratory electrochemical *** electrochemical process was conducted under different experimental conditions,such as various scan rates(mV·s^(–1)),under UV-light and with a 0.07 T *** evolution of CO_(2)substantially improved under UV-light(λ=254 nm)and with 0.07 T magnetic-core treatment;these improvements were attributed to the facts that the UV-light activated the electron-transfer pathway and the magnetic core controlled the pathway of electrontransmission/prevention to protect it from chaotic electron *** all tested nanocomposites,AgCuZnS_(2)–graphene–TiO_(2)absorbed the CO_(2)most strongly and showed the best ability to transfer the electron to reduce the CO_(2)to *** believe that our newly-modeled ternary nanocomposite opens up new opportunities for the evolution of C

关键词： ternary nanocomposite photocatalytic electrochemical CO_(2) reduction UV-light magnetic core

Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts

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Journal of Energy Chemistry 2023年第9期84卷 394-401页

作者： Jeehye Kim cho Hee Lee Yong Hyun Moon Min Hee Lee Eun Hyup Kim Sun Hee choi youn Jeong Jang Jae sung Lee School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Department of Chemical Engineering Hanyang UniversitySeoul 04763Republic of Korea Pohang Accelerator Laboratory(PAL) Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous ***,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) *** eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic *** a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic *** work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.

关键词： Electrochemical nitrogen reduction reaction Ammonia production Phosphorous modified copper electrodes Gas diffusion electrodes Three-phase boundary PTFE coating

Feasibility of full-spectrum endoscopy:Korea's first full-spectrum endoscopy colonoscopic trial

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World Journal of Gastroenterology 2016年第8期22卷 2621-2629页

作者： Jeong-Yeop Song youn Hee cho Mi A Kim Jeong-Ae Kim Chun Tek Lee Moon sung Lee Division of Gastroenterology Department of Internal Medicine LCT Hospital Division of Gastroenterology Department of Internal Medicine Soon Chun Hyang University Bucheon Hospital

AIM: To evaluate the full-spectrum endoscopy(FUSE) colonoscopy system as the first report on the utility thereof in a Korean ***: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects(age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate(PDR), the adenoma detection rate(ADR), and the diverticulum detection rate(DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy ***: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the *** colonoscopy was aborted because of colonoscope ***: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.

关键词： Colonoscopy Colonoscopes Feasibility studies Colonic polyps