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Materials Sciences and Applications 2017年第6期8卷 448-475页

作者： Shinya Inazumi Misato Sekitani kwang-seok chae Ken-Ichi Shishido Department of Civil Engineering College of Engineering Shibaura Institute of Technology Tokyo Japan Graduate School of Global Environmental Studies Kyoto University Kyoto Japan Infra & Offshore Research Team GS Engineering & Construction Seoul Korea Tomec Corporation Tokyo Japan

Asset management is a strategic decision-making aspect of social infra-structure that ensures safety by predicting long-term conditions and maximizing effectiveness under budgetary constraints. Predicting the deterioration of impervious walls is essential in the asset management of coastal landfill sites, particularly in the design of their maintenance and repair strategy. In this paper, a quantitative evaluation of the leakage of toxic substances in coastal landfill sites where deterioration of side impervious walls has decreased the water interception performance is reported. In addition, risk evaluation based on the asset management of the leakage is applied to determine an appropriate repair method. The strategy of repairing the walls when the concentration of the toxic substances leaking into the sea area exceeds the closure and abandonment of coastal landfill sites is demonstrated to be superior. Moreover, the strategy of repairing only the seaside side impervious wall is shown to be cost-effective.

关键词： Coastal Landfill Site Impervious Wall Maintenance Strategy Risk Assessment

Visualization of flow structures inside a conical spouted bed by electrical capacitance volume tomography

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Particuology 2019年第1期17卷 15-25页

作者： Hoon chae Park Hang seok Choi Department of Environmental Engineering Yonsei UniversityWonju 26493Republic of Korea

Electrical capacitance volume tomography (ECVT) was conducted to measure instantaneous gas–solid flow structures in a conical spouted bed. The sensor has 24 electrodes/channels and was used to make three-dimensional measurements of the solid volume fraction. Flow structures in the conical spouted bed were analyzed using quantitative ECVT images. Three-dimensional images of gas–solid flow structures and time-averaged vertical and radial solid volume fraction profiles are presented. Different fluidization regimes in spouted beds were characterized by analyzing pressure fluctuation signals and ECVT images. ECVT was shown to be robust and powerful for the three-dimensional visualization and quantitative measurement of a gas–solid fluidization system.

关键词： Conical spouted bed Electrical capacitance volume tomography Multiphase flow

Improved thermal performance of a hydronic radiant panel heating system by the optimization of tube shapes

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 428-437页

作者： Young T.chae kwang Ho LEE Jae Sung PARK School of Architecture University of Illinois at Urbana-Champaign Department of Architectural Engineering Hanbat National University Department of Mechanical Engineering University of Illinois at Urbana-Champaign

The thermal performance enhancement of the hydronic radiant floor heating system by tube shape refinements is investigated in this *** analytical and detailed numerical modelings are carried out to predict the performance of the radiant *** the simple analytical model briefly investigates the possibility of the effect of the tube shape improvement with the parametric analysis,the commercial computational fluid dynamics(CFD) code(Ansys/CFX) is used to perform the detailed 3D analysis under different tube shape *** fin thickness,the number of fins,and the tube thermal conductivity turn out to have significant effects on the radiant system *** potential energy saving impacts of the tube shape refinements are also *** tube shape improvement turns out to increase the floor surface temperature and to decrease the hot water temperature drop across the system,resulting in heating energy savings.

关键词： Radiant panel system Analytical modeling Computational fluid dynamics(CFD) Tube shape Energy saving

Combustion Characteristics of Solid Refuse Fuels from Different Waste Sources

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Journal of Renewable Materials 2020年第7期8卷 789-799页

作者： Jong Seong chae seok Wan Kim Tae In Ohm Department of Civil and Environmental Engineering Hanbat National UniversityDaejeon34158Korea Department of Fire and Environmental Safety Daegu Haany UniversityDaegu38610Korea

In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion *** are commonly produced by drying combustible waste and removing incombustible matter,resulting in a higher combustibility as compared to the original ***,the characteristics of SRFs may highly vary depending on where and from which materials they were ***,we investigated the characteristics of various SRFs using thermogravimetric analysis(TGA).As a TGA sample is commonly small,on the scale of milligrams,and,unlike homogeneous fuels,SRFs are heterogeneous,individual SRF samples analysed with this method may not represent the bulk material,and sample properties may vary significantly between ***,we further performed combustion experiments using a small-scale combustor and sample sizes from 1 to 10 *** optimise SRF combustor design and determine the SRF characteristics,proximate,elemental,heating value,TG,and differential thermogravimetric analyses were conducted,and weight losses and gas concentrations at different temperatures were measured upon *** lower heating values of the three analysed SRFs were 20,976,16,873,and 19,762 kJ/kg,and their Cl contents were 0.89,0.95,and 1.27 wt.%(legal criterion[Cl]<2.0 wt.%).TGA and small combustor experiments showed that complete weight loss was achieved below 500°***,CO was detected until 620°C.

关键词： Solid refuse fuel small-scale combustor thermogravimetric analysis waste gas concentration

MAINTENANCE OF MULTI-STATE PRODUCTION SYSTEMS DETERIORATED BY RANDOM SHOCKS AND PRODUCTION

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Journal of Systems Science and Systems Engineering 2011年第1期20卷 110-118页

作者： Won seok YANG Dae E.LIM Kyung C.chae Department of Business Administration Hannam University Department of Industrial and Systems Engineering

We consider the preventive maintenance of a production system that is deteriorated by random shocks and the production process itself. The degree of deterioration is modeled by discrete and finite states. Shocks arrive according to a Poisson process and deteriorate the system by random amounts. The system may deteriorate whenever it produces an item. The system is continuously monitored and repaired if the system state is at or above a predetermined level for maintenance. We analyze the lifetime, product quantity, average cost, and average profit considering revenue from the product and cost due to setup, operation, and repair. Assuming a structure of system parameters and costs, using numerical examples, we investigate the impact of production and shock arrivals on the average profit and the optimal maintenance level that maximizes the average profit. The proposed model is applicable to manufacturing tasks in which machines wear due to production, for example, press processes, milling, turning, punching, and drilling.

关键词： Multi-state deterioration random shock maintenance cost-benefit analysis

Collapse behavior evaluation of hybrid thin-walled member by stacking condition

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 135-140页

作者： Kil-Sung LEE Hyeon-Kyeong SEO Yong-June YANG Woo-chae HWANG kwang-Hee IM In-Young YANG R&D Center Dacc LTD. 948-13 Dunsan-ri Bongdong-eup Wanju-gun Jeonbuk 565-902 Korea Departments of Advanced Parts and Materials Engineering Graduate School Chosun University Department of Automotive Engineering Woosuk University Departments of Mechanical Design Engineering Chosun University

The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmentally-friendly aspect, the vehicle structure must be light weight in order to improve the fuel efficiency and reduce the tail gas emission. Therefore, the light weight of vehicle must be achieved in a securing safety status of crash. An aluminum or carbon fiber reinforced plastics (CFRP) is representative one of the light-weight materials. Based on the respective collapse behavior of aluminum and CFRP member, the collapse behavior of hybrid thin-walled member was evaluated. The hybrid members were manufactured by wrapping CFRP prepreg sheets outside the aluminum hollow members in the autoclave. Because the CFRP is an anisotropic material whose mechanical properties, such as strength and elasticity, change with its stacking condition, the effects of the stacking condition on the collapse behavior evaluation of the hybrid thin-walled member were tested. The collapse mode and energy absorption capability of the hybrid thin-walled member were analyzed with the change of the fiber orientation angle and interface number.

关键词： collapse behavior aluminum and CFRP hybrid thin-walled member stacking condition

[001]-texturing of(K,Na)NbO_(3)-based piezoceramics with a pseudocubic structure and their application to piezoelectric devices

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Journal of Materiomics 2024年第3期10卷 632-642页

作者： Su-Hwan Go seok-Jung Park Seung-Hyun Kim seok-June chae Eun-Ji Kim Geun-Su Lee Sahn Nahm Department of Materials Science and Engineering Korea UniversitySeoul02841Republic of Korea

0.96(K_(0.5)Na_(0.5-z)Li_(z))(Nb_(0.92)Sb_(0.08))O_(3)-0.04(Ca_(0.5)Sr_(0.5))ZrO_(3)[(KN_(0.5-z)L_(z))NS-CSZ]piezoceramics(0≤z≤0.04)were aligned in the[001]orientation using 3%(in mole)NaNbO_(3)templates with a large Lotgering factor(>97%).Their crystal structures transformed from the orthorhombic-pseudocubic(O-P)structure to the orthorhombic-tetragonal-pseudocubic(O-T-P)structure with an increasing *** P structure was interpreted as a rhombohedral R3m *** piezoelectricity of the compositions increased after[001]-texturing,and the enhancement was proportional to the O phase *** composition(z=0.03)exhibited the highest piezoelectric constant(d_(33);670 pC/N)and electromechanical coupling factor(k_(p);0.56).Piezoelectric energy harvesters were produced using the untextured and textured samples(z=0.03).The textured harvester delivered a large power density of 26.6 mW/mm^(3),which was larger than that of the untextured harvester owing to the enhanced kp and d_(33)×g_(33) of the textured piezoceramic.A multilayer actuator was produced using the textured sample(z=0.03),and it exhibited a large acceleration(44.2 G)and displacement(±3,730 mm)at±25 ***,the[001]-textured(KN_(0.47)L_(0.03))NS-CSZ piezoceramic is suitable for piezoelectric energy harvesters and actuators.

关键词： KNN-Based piezoceramic Lead-free Energy harvester Actuator Reactive template grain growth

Enhanced biometric encryption algorithm for private key protection in BioPKI system

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Journal of Central South University 2014年第11期21卷 4286-4290页

作者： Cheol-Joo chae kwang-Nam Choi Kiseok Choi Jae-Soo Kim Yong Ju Shin Korea Institute of Science and Technology Information 245 DaehangnoYuseong-gu Daejeon Korea

Protection of private key is the most critical part in public key infrastructure(PKI) system since it depends on the confidentiality of private key. Thread of password detection has been known as the vulnerability in this PKI system. Recently, studies have been conducted on Bio PKI system that uses the biometric information of users in order to replace the password type of private key protection in PKI system. However, Bio PKI system also has vulnerability in that biometric information used for protection of private key cannot be reused once it is stolen or lost. So, we propose the method to protect the private key using FIDSEQi which binds sequence to biometric information. The proposed method enhances reusability of biometric information and presents higher attack complexity than the method of authentication by cross matching single biometric information.

关键词： BioPKI system fingerprint biometric encryption secret share

Prevalence of coronavirus from diarrheic calves in the Republic of Korea

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Asian Pacific Journal of Tropical Biomedicine 2018年第1期8卷 1-6页

作者： Jinho Park Du-Gyeong Han Su Hee Kim Jeong-Byoung chae Joon-seok chae Do-Hyeon Yu Kyoung-Seong Choi College of Veterinary Medicine Chonbuk National University Department of Animal Science and Biotechnology College of Ecology and Environmental Science Kyungpook National University Animal Disease & Biosecurity Team National Institute of Animal Science Rural Development Administration Laboratory of Veterinary Internal Medicine BK21 PLUS Program for Creative Veterinary Science Research Research Institute for Veterinary Science and College of Veterinary Medicine Seoul National University College of Veterinary Medicine Gyeongsang National University

Objective: To investigate the prevalence of bovine coronavirus(BCo V), bovine rotavirus, and bovine viral diarrhea virus in the feces of normal and diarrheic Korean native calves aged 1-81 days between April and October of 2016 in the Republic of Korea. Methods: Samples were obtained from 50 normal and 93 diarrheic(56 semi-formed, 28 loose, and 9 watery feces) calves in six different regions of northern and southern Korea. These fecal samples were tested for BCo V, bovine rotavirus, and bovine viral diarrhea virus by RT-PCR. Results: Among the three pathogens examined, infection with BCo V was especially prominent in relation to diarrhea among calves aged 1-21 days [odds ratio(OR)=9.3, 95% confidence interval(CI): 1.1-78.9; P=0.02). Infection with BCo V alone(OR=2.9; 95% CI: 1.1-7.6; P=0.03) or coinfection of BCo V with bovine viral diarrhea virus(OR=3.6; 95% CI: 1.0-12.4; P=0.04) was significantly associated with the development of loose feces. Grazing and colostrum intake strongly reduced the occurrence of diarrhea as compared to housed calves(OR=0.2; 95% CI: 0.1-0.4; P=0.00) and calves that had not been fed colostrum(OR=0.2; 95% CI: 0.1-0.7; P=0.02), respectively. Conclusions: The present study suggests that BCo V is involved in calf diarrhea in the Republic of Korea. Therefore, grazing and colostrum intake is recommended for preventing and controlling calf diarrhea caused by BCoV.

关键词： Calf diarrhea Bovine coronavirus Bovine viral diarrhea virus Loose feces Grazing

Debris Flow in Metropolitan Area - 2011 Seoul Debris Flow

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Journal of Mountain Science 2013年第2期10卷 199-206页

作者： Chan-Young YUNE Yun-Ki chae Joongcheol PAIK Gihong KIM Seung-Woo LEE Heung-seok SEO Department of Civil Engineering Gangneung-Wonju National University Department of Civil Engineering Gangneung-Wonju National UniversityGangneungSouth Korea Department of Construction Engineering Gangneung Yeongdong College

A large number of debris flows occurred simultaneously at around 8:30 to 8:50 *** July 27,2011,at the center of Seoul,*** area is located in the southern part of Seoul and is a densely populated *** a result of the debris flow event,16 people were killed,30 houses were buried,and 116 houses were damaged around Umyeon Mountain,a relatively small mountain with a height of 312.6 *** the debris flow event,field investigations on the initiation and transportation zones of debris flows have been carried *** data were collected from the automatic weather stations(AWSs) which are operated by the Korea Meteorological Administration(KMA).Video files recorded by residents were also acquired and used to analyze the flow characteristics of the debris *** investigation shows that about 40 debris flows occurred around Umyeon Mountain and most of the debris flows were initiated by small slope *** effects of the precipitation that triggered the debris flows were analyzed as well.A landslide hazard map which considers slope gradient and aspect,strength of soil,hazard record,rainfall conditions,and vegetation,was constructed and compared with the initiation zones of debris flows.

关键词： Debris flows Field investigation Rainfall Flow characteristics Hazard map