Active response control of an offshore structure under wave loads using a modified probabilistic neural network

Chang, Seongkyu,Kim, Dookie,Chang, Chunho,Cho, Sung Gook Springer-Verlag 2009 Journal of Marine Science and Technology Vol.14 No.2

滋陰丹이 皮膚의 老化에 미치는 影響

박성규,김수남,이종찬,김한성,김연준,이병곤,장이섭 대한본초학회 2004 大韓本草學會誌 Vol.19 No.1

Objectives: Jaeum-Dan (JED) I and II are new formulas composed with oriental herbs. We investigated the anti-aging effects on skin with water extracts of JED 1 , JED II, JJZD IIJ and each Bupleuri Radix, Lonicerae Caulis, Coicis Semen, Armeniacae Amarum Semen, Plantaginis Herba. Methods: We measured various effects related to skin such as the proliferation of keratinocytes, the inhibition of reactive oxygen species (ROS) generation, 5a-reductase activity, the gap junctional intercellular communication, the amount of melanin and the synthesis of MMP-1 and type I procollagen. Results: The proliferation of keratinocytes were increased in JED I , 11, ID and water extracts of Bupleun Radix, Plantaginis Herba. The production of ROS were decreased in JED I , II, IJl and water extract of Bupleun Radix. 5a-reductase activity were decreased in JED I , II, lII and water extract of Lonicerae Caulis. Gap junctional intercellular communcation were increased to normal level in water extract of Coicis Semen. The amount of melanin were decreased in JED I , II, IU and water extract of Armeniacae Amarum Semen, Plantaginis Herba. The synthesis of MMP-1 and type I procollagen were positive in JED I , II, ID and water extract of Plantaginis Herba. Conclusions: The results of our study indicate that each 5 herbs have anti-aging effects and the complex of JED I with rl were best in anti-aging effects on skin.

차량 거동안정성 향상을 위한 섀시협조제어 로직개발

정대종(Daejong Chang),김완섭(Wansup Kim),김성규(Seongkyu Kim),김성주(Seongjoo Kim) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.5_2

This paper describes the Unified Chassis Control System which improves stability of the vehicle by communicating sensor information of chassis. The Electric Power Steering receives road condition from the Antilock Brake System during quick braking maneuver, the Electric Power Steering automatically corrects Steering angle to guarantee stable straight-line deceleration.

Case Study of Ground-Based Glaciogenic Seeding of Clouds over the Pyeongchang Region

Yang, Ha-Young,Chang, Ki-Ho,Chae, Sanghee,Jung, Eunsil,Seo, Seongkyu,Jeong, Jin-Yim,Lee, Jung-Ho,Ro, Yonghun,Kim, Baek-Jo Hindawi Limited 2018 Advances in meteorology Vol.2018 No.-

<P>Ground-based glaciogenic seeding experiments were conducted at the Daegwallyeong Cloud Physics Observation Site (CPOS) from 2012 to 2015 for the target area Yongpyeong, which lies 9 km away. The preseeding (NOSEED) and seeding (SEED) periods were defined based on the simulation results of AgI concentration (>10 L<SUP>−1</SUP>) in the Weather Research and Forecast (WRF) model with the modified Morrison scheme in microphysics. It was difficult to determine whether snow enhancement via seeding occurred over the entire target area due to uncertainties associated with limitations such as observations and numerical model based on only two points (seeding and target sites). However, in three of four cases, the vertical reflectivity from micro rain radar, total concentration, and average size of snow particles observed at PARSIVEL and precipitation increased in the seeding effect time. In two of four cases, the simulated increased precipitation during the seeding effect time was also observed. In one case that did not show changes after seeding, it is analyzed that a sufficient cloud depth was not supplied to the seeding region due to the blocking effect of the Taebaek Mountains.</P>

음식물 침출수를 처리하는 막결합 고온혐기성 소화시스템에서 교차여과와 막간압력이 파울링에 미치는 영향

Youngo Kim,Dukwoo Jun,Seongkyu Yoon,Chunghee Chang,Jaeho Bae,Kwansun Yoo,Jeonghwan Kim 한국막학회 2011 멤브레인 Vol.21 No.4

음식물 폐기물 침출수를 처리하는 분리막 결합 고온 혐기성소화공정(생물학적 반응조) (Anaeorobic Membrane Bioreactor, AnMBR)의 파일럿 운전에서 분리막의 교차여과 속도와 막간압력이 파울링에 미치는 영향을 관찰하였다. 연구 결과 정압여과 하에서 교차여과 속도가 증가할수록 파울링의 속도는 현격히 감소되었다. 그러나 이와 같은 영향은 낮은 막간압력에서 더욱 효과적이었다. 막간압력이 증가할수록 여과대상 물질의 압축성으로 인해 투과성이 상대적으로 낮은 파울링층(혹은 케익층)이 분리막 표면에 형성된 것에 기인된 듯하다. 여과대상 시료의 입도분석을 해 본 결과 입자크기는 약 10~100mum 범위에서 분포하였고 이에 따라 브라운확산에 의한 역수송보다 분리막 표면에서 교차여과에 의해 발생하는 전단력이 입자의 역수송에 더욱 기여하고 있음을 예측할 수 있었으며 이는 AnMBR의 연속운전을 통해 재확인할 수 있었다. 운전 후 막 부검을 실시한 결과 유기 및 무기 파울링이 모두 관찰되었으나 어느 것이 지배적인 파울링 기작을 나타내는지는 앞으로 더욱 연구가 필요하다. 무기 파울링의 경우 대부분 분리막 표면에서 스케일링 형성이 지배적이었으며, 따라서 분리막의 공극 막힘에 주로 기여하는 작은 콜로이드성 유기물질의 경우 분리막 표면에서 전단력에 의한 역수송 효과는 그다지 크지 않을 것으로 사료된다. The effect of cross-flow velocity and transmembrane pressure (TMP) on membrane fouling was observed from pilot-scale operation of thermophilic anaerobic membrane bioreactor (AnMBR) treating food waste leachate. It was found that fouling rate was reduced significantly as cross-flow velocity increased at constant TMP mode of operation while this effectiveness was more pronounced at lower TMP. Higher TMP resulted in less permeable fouling layer possibly due to compressibility of foulant material on membrane surface. Particle sizes of membrane concentrate ranged from 10 to 100mum, implying that shear-induced diffusion enhance back transport of these particle sizes away from the membrane effectively. From the continuous operation of AnMBR, it was confirmed that shear rate played an important role in the reduction of membrane fouling. Membrane autopsy works at the end of operation of AnMBR showed clearly that both organic and inorganic fouling were significant on membrane surface. Surface shear by cross-flow velocity was expected to be less effective to remove irreversible fouling which can be mainly caused by the adsorption of organic colloidal materials into membrane pores.

Multiple wall dampers for multi-mode vibration control of building structures under earthquake excitation

Rahman, Mohammad Sabbir,Chang, Seongkyu,Kim, Dookie Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4

One of the main concerns of civil engineering researchers is developing or modifying an energy dissipation system that can effectively control structural vibrations, and keep the structural response within tolerable limits during unpredictable events like earthquakes, wind and any kind of thrust load. This article proposes a new type of mass damper system for controlling wideband earthquake vibrations, called Multiple Wall Dampers (MWD). The basic principle of the Tuned Mass Damper (TMD) was used to design the proposed wall damper system. This passive energy dissipation system does not require additional mass for the damping system because the boundary wall mass of the building was used as a damper mass. The multi-mode approach was applied to determine the location and design parameters of the dampers. The dampers were installed based on the maximum amplitude of modes. To optimize the damper parameters, the multi-objective optimization Response Surface Methodology was used, with frequency response and maximum displacement as the objective functions. The obtained structural responses under different earthquake forces demonstrated that the MWD is one of the most capable tools for reducing the responses of multi-storied buildings, and this system can be practically used for new and existing building structures.

Vibration control of 3D irregular buildings by using developed neuro-controller strategy

Bigdeli, Yasser,Kim, Dookie,Chang, Seongkyu Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.6

This paper develops a new nonlinear model for active control of three-dimensional (3D) irregular building structures. Both geometrical and material nonlinearities with a neuro-controller training algorithm are applied to a multi-degree-of-freedom 3D system. Two dynamic assembling motions are considered simultaneously in the control model such as coupling between torsional and lateral responses of the structure and interaction between the structural system and the actuators. The proposed control system and training algorithm of the structural system are evaluated by simulating the responses of the structure under the El-Centro 1940 earthquake excitation. In the numerical example, the 3D three-story structure with linear and nonlinear stiffness is controlled by a trained neural network. The actuator dynamics, control time delay and incident angle of earthquake are also considered in the simulation. Results show that the proposed control algorithm for 3D buildings is effective in structural control.

Effects of vertical stiffness of rail fastening system on the behavior of the end regions of railway bridges with slab tracks

Deokyong Sung,Sukhoon Pyo,Seongkyu Chang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.2

A railway bridge with slab track is subjected to end rotations because of the deflection of the girder during train operation. At the ends of a slab track, the end rotation of the bridge girder causes uplift deformation of the slab track, and leads to compressive stresses in the rail fasteners. In this study, a prototype bridge consisting of one span of a girder and one span of an abutment along with a slab track was constructed, and the uplift and compressive forces generated in the rail fastening system were experimentally analyzed. To effectively analyze the experimental results using a numerical method, a series of finite element analyses were performed considering the nonlinear nature of the rail fastening system. A comparison between the experimental and analytical results indicated that the higher the stiffness of the rail fastening system, the greater the uplift and compressive forces. In addition, a nonlinear model provided better correlation with the experimental results than a linear model. Therefore, when reviewing the serviceability of the rail fastening system at railway bridge ends, an adequate finite element model considering the uplift and compressive forces in the rail fastening system should be used.

세미커플 해석 방법을 사용한 해상풍력타워의 지진응답해석

파리아샤민 ( Sharmin Faria ),모샤라프 ( Hussan Mosaruf ),장성규 ( Chang Seongkyu ),김두기 ( Kim Dookie ),조성국 ( Cho Sung Gook ) 한국구조물진단유지관리공학회 2016 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.20 No.1

가압펌프 단독형 미세기포 발생장치의 기초 운전특성

양하연 ( Yang Hayeon ),이성규 ( Lee Seongkyu ),장여주 ( Jang Yeoju ),박나리 ( Park Nari ),장향연 ( Chang Hyangyoun ),임현만 ( Lim Hyunman ),김원재 ( Kim Weonjae ) 한국물환경학회 2020 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2020 No.-

여러 환경분야에서 부상분리공정(Dissolved Air Flotation,DAF)의 활용이 확대되고 있다. DAF 공정의 핵심설비라고 할 수 있는 기존 미세기포 발생장치는 장치의 구성이 복잡하여 운전 및 유지관리가 쉽지 않고, 고가여서 소규모 사업자가 사용하기에 많은 어려움이 따른다. 따라서 본 연구에서는 이를 대체할 수 있는 고효율·저비용의 미세기포 발생장치를 개발하고자 하였다. 이 미세기포 발생장치는 ① 공기 자흡식 구조를 갖고 있어 별도의 콤프레서 설비가 필요치 않고, ② 공기가압탱크(AST; Air Saturation Tank) 내 압력 및 수위조절 기구가 없으며, ③ 물과 공기가 AST의 하부로부터 상부로 수류방향 (co-current flow)으로 흐르면서 포화농도까지 용해되는 특징이 있기 때문에, 구조가 매우 단순하고, 유지관리가 용이하며, 제조 및 운전비용이 저렴한 것이 장점이다. 가압펌프는 SPCO(社) VMC 5-9 모델(3상, 3.75 kW, 380 V, 60 Hz)을 사용하였으며, AST는 120 mmW × 360 mmL × 750 mmH(내부용적: 32.4 L)의 규격으로 제작하였다. 본 연구에서는 유입유량, 공기주입량, 공기물비(BVC; Bubble Volume Concentration), 운전압력, 미세기포 입경분포 및 소비전력 등 새로 개발한 미세기포 발생장치의 기초적 운전특성을 분석하였다. 이를 바탕으로 미세기포가 안정적이고 에너지 효율적으로 생성되는 최적 운전조건(유입유량, 공기주입량 및 운전압력)을 결정하였다. 운전압력을 3 kgf/cm²에서 7 kgf/cm²까지 증가시킴과 동시에 공기주입량을 2 L/min에서 최대주입량까지 변화시키면서 해당 조건별 적정 공기주입량을 산정하였다. 운전압력이 증가함에 따라 유입유량은 3 - 6 kgf/cm²의 조건에서 약 74 - 57 L/min의 범위를 유지하였으며, 7 kgf/cm²의 조건에서 42 - 39 L/min으로 급감하였다. 설정된 압력에서의 최대주입량은 10분간 미세기포 발생장치를 가동시켰을 때 지름 1 cm 이상의 거대기포가 발생하지 않는 최대의 공기량으로 정의하였다. 실험 결과, 3 kgf/cm²의 조건에서는 공급된 공기의 용해율이 낮을 뿐만 아니라 대기압 조건에서 미세기포의 발생이 원활치 않았고, 4 - 5 kgf/cm²의 운전압력 조건에서는 평균 7%의 공기가 용존가능하였으며, 그 비율을 9% 이상으로 올리기 위해서는 6 kgf/cm² 이상의 압력이 필요하였다. 운전압력 6 kgf/cm²에서 최대주입량은 5.0 L/min(유입유량: 57.6 L/min), 7 kgf/cm²에서 4.0 L/min (유입유량: 40.4 L/min)로 분석되었으며(BVC는 각각 8.7%, 9.9%), 주입된 공기 전량이 용해된 후 후단의 대기압 조건에서 안정적으로 미세기포로 전환되었다. 따라서, 유입유량과 BVC를 동시에 고려했을 때, 미세기포 발생효율을 제고하기 위한 가압펌프 단독형 미세기포 발생장치의 적정 유입유량은 약 57 - 68 L/min, 공기주입량은 약 4.0 - 4.5 L/min, 운전압력은 4 - 6 kgf/cm²의 범위인 것으로 판단된다.