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中国有色金属学会会刊：英文版 2012年第S3期22卷 596-604页

作者： Dong-yoon KIM Young-Whan PARK Department of Mechanical Engineering Pukyong National University

Aluminum welding using a hybrid system with a laser and scanner welding head was performed under various welding conditions to verify the feasibility of applying an aluminum alloy to a car *** experimental material was 5J32 aluminum alloy,and the laser power,welding speed,and laser incidence angle were used as the control *** weld bead shape and the tensile shear strength were evaluated in order to understand the aluminum lap joint weld *** of variance (ANOVA) was conducted to identify the effect of the process variables on the tensile shear *** strength estimation models using three different regression models were also *** input variables were the laser power,welding speed,and laser incidence angle,and the output was the tensile shear *** the models,the second-order polynomial estimation model had the best estimation performance,and the average error rate of this model was 0.058.

关键词： laser welding scanner remote welding 5J32 aluminum alloy regression model

Inverse Problem of Flame surface Properties of Wood using a Repulsive Particle swarm Optimization Algorithm

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Journal of Thermal science 2015年第2期24卷 173-178页

作者： Kyung-Beom yoon Won-Hee Park Korea Conformity Laboratories 199Gasan-digital 1-roGeumcheon-guSeoul 153-803Korea Korea Railroad Research Institute 176 Cheoldobangmulgwan-roUiwang-siGyeonggi-do 437-757Korea Korea University of science and Technology (UsT) 217 Gajeong-roYuseong-guDaejeon 305-350 Korea

The convective heat transfer coefficient and surface emissivity before and after flame occurrence on a wood specimen surface and the flame heat flux were estimated using the repulsive particle swarm optimization algorithm and cone heater test results. The cone heater specified in the IsO 5660 standards was used, and six cone heater heat fluxes were tested. Preservative-treated Douglas fir 21 mm in thickness was used as the wood specimen in the tests. This study confirmed that the surface temperature of the specimen, which was calculated using the convective heat transfer coefficient, surface emissivity and flame heat flux on the wood specimen by a repulsive particle swarm optimization algorithm, was consistent with the measured temperature. Considering the measurement errors in the surface temperature of the specimen, the applicability of the optimization method considered in this study was evaluated.

关键词： Repulsive particle swarm optimization Cone calorimeter Flame heat flux Flame surface properties

Designing a Biomimetic Ornithopter Capable of sustained and Controlled Flight

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Journal of Bionic Engineering 2008年第1期5卷 39-47页

作者： Joon Hyuk Park Kwang-Joon yoon Department of Aerospace Information system and Artificial Muscle Research Center Konkuk University Seoul 143-701 Korea

We describe the design of four ornithopters ranging in wing span from 10 cm to 40 cm, and in weight from 5 g to 45 g. The controllability and power supply are two major considerations, so we compare the efficiency and characteristics between different types of subsystems such as gearbox and tail shape. Our current omithopter is radio-controlled with inbuilt visual sensing and capable of takeoff and landing. We also concentrate on its wing efficiency based on design inspired by a real insect wing and consider that aspects of insect flight such as delayed stall and wake capture are essential at such small size. Most importantly, the advance ratio, controlled either by enlarging the wing beat amplitude or raising the wing beat frequency, is the most significant factor in an ornithopter which mimics an insect.

关键词： biomimetic ornithopter flapping wing unsteady state low Reynolds number

Trilobite Biostratigraphy of the lower Paleozoic(Cambrian–Ordovician)Joseon supergroup,Taebaeksan Basin,Korea

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Acta Geologica sinica(English Edition) 2016年第6期90卷 1976-1999页

作者： CHOI Duck K LEE Jeong Gu LEE seung-Bae PARK,Tae-yoon s. HONG Paul s. Research Institute of Basic sciences Seoul National UniversitySeoul 151-747Korea Ministry of science ICTand Future PlanningGwacheon 427-700Korea Korea Institute of Geoscience and Mineral Resources Daejeon 305-350Korea Korea Polar Research Institute Incheon 406-840Korea

In Korea, trilobites are among the most intensively studied fossil groups in the past century and provide invaluable information about lower Paleozoic stratigraphy, paleogeography, and tectonics of the Korean Peninsula. Trilobites occur in the lower Paleozoic Joseon supergroup of the Taebaeksan Basin which was part of the sino-Korean Craton in the Paleozoic. The Joseon supergroup is divided into the Taebaek, Yeongwol, and Mungyeong groups. The Taebaek and Yeongwol groups are richly fossiliferous, while the Mungyeong Group is poorly fossiliferous. Contrasting trilobite faunal contents of the Taebaek and Yeongwol groups resulted in two separate biostratigraphic schemes for the Cambrian–Ordovician of the Taebaeksan Basin. A total of 22 biozones or fossiliferous horizons were recognized in the Taebaek Group; 19 zones were established in the Yeongwol Group; and four biozones were known from the Mungyeong Group. These trilobite biozones of the Taebaeksan Basin indicate the Joseon supergroup ranges in age from the Cambrian series 2 to Middle Ordovician and can be correlated well with the formations of North China, south China, and Australia.

关键词： Trilobites biostratigraphy Cambrian–Ordovician Taebaeksan Basin

Optimization of Pyrolysis Properties using TGA and Cone Calorimeter Test

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Journal of Thermal science 2013年第2期22卷 168-173页

作者： Won-Hee Park Kyung-Beom yoon Eco-Transport systems Research Division Korea Railroad Research Institute Department of Mechanical Engineering Chung-Ang University

The present paper describes an optimization work to obtain the properties related to a pyrolysis process in the solid material such as density, specific heat, conductivity of virgin and char, heat of pyrolysis and kinetic parameters used for deciding pyrolysis rate. A repulsive particle swarm optimization algorithm is used to obtain the pyrolysis-related properties. In the previous study all properties obtained only using a cone calorimeter but in this paper both the cone calorimeter and thermo gravimetric analysis (TGA) are used for precisely optimizing the pyrolysis properties. In the TGA test a very small mass is heated up and conduction and heat capacity in the specimen is negligible so kinetic parameters can first be optimized. Other pyrolysis-related properties such as virgin/char specific heat and conductivity and char density are also optimized in the cone calorimeter test with the already decided parameters in the TGA test.

关键词： Pyrolysis properties Thermogravimetric analysis Cone calorimeter Repulsive particle swarmoptimization

striping and scheduling for Large scale Multimedia servers

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Journal of Computer science & Technology 2004年第6期19卷 885-895页

作者： Kyung-OhLee Jun-HoPark yoon-YoungPark DepartmentofComputerscience SunmoonUniversity100TangJeonMyunKalsanRiAsansiChunNam336-840Korea

When designing a multimedia server, several things must be decided: which scheduling scheme to adopt, how to allocate multimedia objects on storage devices, and the round length with which the streams will be serviced. several problems in the designing of large-scale multimedia servers are addressed, with the following contributions: (1) a striping scheme is proposed that minimizes the number of seeks and hence maximizes the performance; (2) a simple and efficient mechanism is presented to find the optimal striping unit size as well as the optimal round length, which exploits both the characteristics of VBR streams and the situation of resources in the system; and (3) the characteristics and resource requirements of several scheduling schemes are investigated in order to obtain a clear indication as to which scheme shows the best performance in realtime multimedia servicing. Based on our analysis and experimental results, the CsCAN scheme outperforms the other schemes. It is believed that the results are of value in the design of effective large-scale multimedia servers. Keywords realtime multimedia - storage server - scheduling - data placement - buffer management - variable bit rate This work was supported in part by the University IT Research Center Project and sunmoon University Research Project.Kyung-Oh Lee is an associate professor in the Faculty of Computer and Information sciences, sunmoon University, Korea. He received his B.s., M.s. and Ph.D. degrees in computer science from seoul National University in 1989, 1994 and 1999, respectively. His current research interests include multimedia system, database, mobile communication. He is a member of KIPs (Korea Information Processing society).Jungho-Ho Park is a professor in the Divisions of Computer and Information sciences, sunmoon University, Korea. He received his M.s. and Ph.D. degrees in computer science from Osaka University in 1987 and 1990, respectively. His current research interests include d

关键词： realtime multimedia storage server scheduling data placement buffer management variable bit rate

A Dynamical system-Based Framework for Dimension Reduction

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Communications on Applied Mathematics and Computation 2024年第2期6卷 757-789页

作者： Ryeongkyung yoon Braxton Osting Department of Mathematics University of UtahSalt Lake CityUTUSA

We propose a novel framework for learning a low-dimensional representation of data based on nonlinear dynamical systems,which we call the dynamical dimension reduction(DDR).In the DDR model,each point is evolved via a nonlinear flow towards a lower-dimensional subspace;the projection onto the subspace gives the low-dimensional *** the model involves identifying the nonlinear flow and the *** the equation discovery method,we represent the vector field that defines the flow using a linear combination of dictionary elements,where each element is a pre-specified linear/nonlinear candidate function.A regularization term for the average total kinetic energy is also introduced and motivated by the optimal transport *** prove that the resulting optimization problem is well-posed and establish several properties of the DDR *** also show how the DDR method can be trained using a gradient-based optimization method,where the gradients are computed using the adjoint method from the optimal control *** DDR method is implemented and compared on synthetic and example data sets to other dimension reduction methods,including the PCA,t-sNE,and Umap.

关键词： Dimension reduction Equation discovery Dynamical systems Adjoint method Optimal transportation

Intelligent low-level RF system by non-destructive beam monitoring device for cyclotrons

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Chinese Physics C 2016年第4期40卷 98-105页

作者： M.s.sharifi Asadi Malafeh M.Ghergherehchi H.Afarideh J.s.Chai yoon sang Kim Department of Energy Engineering&Physics Amirkabir University of TechnologyTehranIran College of Information&Communication Engineering Sungkyunkwan UniversitySuwonKorea schoot of Computer science and Engineering Korea University of Technology and EducationCheonanKorea

The project of a 10 Me V PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of the cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work an Intelligent Low Level Radio Frequency Circuit or ILLRF, suitable for most AVF cyclotron accelerators, is designed using a beam monitoring device and narrow band tunable band-pass filter. In this design, the RF phase detection does not need signal processing by a microcontroller.

关键词： accelerator destructive stabilize tunable resonant acceleration narrow adjust bunch correction

A macroscopic constitutive model of shape memory alloy considering cyclic effects

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science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 755-764页

作者： ZHOU Bo yoon sung-Ho College of Pipeline and Civil Engineering China University of Petroleum school of Mechanical Engineering Kumoh National Institute of Technology

This paper presents a macroscopic constitutive model reproducing the hysteretic behaviors of the superelastic shape memory alloy (sMA) under cyclic loading. The progressive increase of residual strain with the increased cycle number in such materials is assumed to be a consequence of the progressive increase of residual stress-induced martensitic volume fraction upon the cyclic effects. The progressive decrease of phase transformation critical stresses with the increased cycle number in such materials is assumed to be a result from the progressive increase of phase transformation critical temperatures upon the cyclic effects. A cyclic evolution equation is supposed to describe the influences of cycle effects on the material properties of the sMA under cyclic loading. A phase transformation equation expressing the phase transformation behaviors of the sMA under cyclic loading is established based on the differential relationship between martensitic volume fraction and the free energy increment of phase transformation. A mechanical constitutive equation predicting the mechanical characteristics of the sMA under cyclic loading is developed on the basis of thermodynamics and continuum mechanics. The cyclic evolution equation, phase transformation equation, and mechanical constitutive equation together compose the presented macroscopic constitutive model considering cyclic effects. Results of the numerical simulations illustrate that it can well reproduce the superelastic hysteretic behaviors of the sMA under cyclic loading.

关键词： shape memory alloy cyclic effect cyclic evolution equation phase transformation equation mechanical constitutive equation

Performance evaluations on inner vs. outer decomposition first parallel join algorithms for two nested loop joins

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Journal of Central south University 2014年第10期21卷 3873-3882页

作者： seo-Young NOH Heejun yoon Il-Yeon YEO yoon-su JEONG Hyungwoo PARK National Institute of supercomputing and Networking Korea Institute of Science and Technology Information Department of Information Communication Engineering Mokwon University

Two popular traditional join algorithms and their parallel versions are introduced. When designing join algorithms in serial computing environment, decomposing inner relation is considered as the right direction to save disk I/Os. However, two different decomposition algorithms are compared, such as inner vs. outer decomposition first algorithms for tuple-based and block-based nested loop joins, showing that the proposed approach is 20% better than general approach. Also lemmas are proved, when we have to use the outer decomposition first parallel join algorithms.

关键词： parallel join performance inner decomposition outer decomposition