• Title/Summary/Keyword: CASE

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A Case Study on the Reinforcement of Existing Damaged Geogrid Reinforced Soil Wall Using Numerical Analyses (수치해석을 이용한 기존 피해 보강토 옹벽의 보강에 관한 사례 연구)

  • Won, Myoung-Soo;Langcuyan, Christine P.;Choi, Jeong-Ho;Ha, Yang-Seong
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.1
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    • pp.75-82
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    • 2020
  • There have been often cases of collapse for geogrid reinforced soil (GRS) retaining wall. Hence, social interest in the reinforcement and restoration of the collapsed GRS wall is increasing day by day. However, there are only few researches. For this reason, a series of numerical analyses using the Plaxis 2D program was conducted in this study to analyze the suitable reinforcement methods that can be applied on the existing damaged GRS wall caused by overturning of the modular blocks facing and the surface settlement at the backfill as the results from the design failure. The restoration plan used in this study is composed of two cases: (Case 1) soil nailing reinforcement and reinforced concrete (RC) wall facing construction on the existing damaged GRS wall; and (Case 2) removal of the entire damaged GRS wall and then reconstruction. The results on the internal stability of the GRS wall show that Case 1 obtained a greater safety factor than Case 2 for tensile force while Case 2 had a greater safety factor than Case 1 for pullout failures. Case 1 was found to be more stable than Case 2 in terms of the global slope safety by shear strength reduction method and the external deformation behavior by numerical analysis. In this study, the existing damaged GRS wall which was reinforced using Case 1 method shows more stable external behavior.

Dynamic Behavior of Caisson Type Breakwater Considering Typhoon-induced Wave Loading Before and After Earthquakes (태풍 파랑과 지진을 연계한 케이슨식 방파제의 동적거동)

  • Hyeonsu Yun;Byeongjin Roh;Seong-Kyu Yun;Gichun Kang
    • Journal of the Korean Geosynthetics Society
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    • v.23 no.1
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    • pp.49-60
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    • 2024
  • Recently, the frequency and intensity of typhoon-induced wave loading are increasing due to changed marine environments such as climate change. In addition, frequent earthquakes are causing a lot of damage around the world, including in Japan, Chile, Haiti, China, and Indonesia. In Korea, damage from typhoons has also been increasing since the 2000s, and the frequency and intensity of earthquakes are also increasing. Korea is surrounded by sea on three sides, so typhoons can cause a lot of damage to coastal structures, and earthquakes also cause a lot of damage to coastal structures. As such, the frequency and intensity of typhoon-induced wave loading and earthquakes are increasing both domestically and internationally, but there is no research linking typhoons and earthquakes. Therefore, in this study, numerical analysis was performed for a total of four cases by linking typhoon waves and earthquakes to the caisson breakwater. Numerical analysis was performed by applying wave loads in Case 1 and seismic wave in Case 2, seismic wave after wave loads in Case 3, and wave loads after seismic wave in Case 4. As a result of the numerical analysis, it was confirmed that in Case 3 and Case 4, which linked a typhoon and earthquakes, the damage caused by each load increased compared to Case 1 and Case 2 because the load was applied while the existing ground strength was reduced. In addition, it was confirmed that the greatest damage occurred in Case 3, in which seismic wave were applied after the wave loads.

THE THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE PARTIALLY EDENTULOUS IMPLANT PROSTHESIS WITH VARYING TYPES OF NON-RIGID CONNECTION (부분 무치악 임플랜트 보철 수복시 자연치와의 비고정성 연결형태에 따른 3차원 유한요소법적 연구)

  • Lee, Seon-A;Chung, Chae-Heon
    • The Journal of Korean Academy of Prosthodontics
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    • v.34 no.1
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    • pp.101-124
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    • 1996
  • In this study, we designed the finite element models of mandible with varying their connecting types between the prosthesis on implant fixture and 2nd premolar, which were free-standing case(Mf), precision attachment case(Mp), semiprecision attachment case(Ms) and telescopic case(Mt). The basic model of the designed finite element models, which contained a canine and the 1st & 2nd premolar, was implanted in the edentulous site of the 1st & 2nd molar by two implant fixtures. We applied the load in all models by two ways. A vertical load of 200N was applied at each central fossa of 2nd premolar and 1st implant. A tilting load of 20N with inclination of $45^{\circ}$ to lingual side was applied to buccal cusp tips of each 2nd premolar and 1st implant. And then we analyzed three-dimensional finite element models, making a comparative study of principal stress and displacement in four cases respectively. Three-dimensional finite element analysis was performed for the stress distribution and the displacement using commercial software(IDEAS program) for SUN-SPARC workstation. The results were as follows : 1 Under vertical load or tilting load, maximum displacement appeared at the 2nd premolar. Semiprecision case showed the largest maximum displacement, and maximum displacement reduced in the order of precision attachment, free-standing and telescopic case. 2. Under vertical load. the pattern of displacement of the 1st implant appeared mesio-inclined because of the 2nd implant splinted together. But displacement pattern of the 2nd premolar varied according to their connection type with prosthesis. The 2nd premolar showed a little mesio-inclined vertical displacement in case of free-standing and disto-inclined vertical displacement due to attachment in case of precision and semiprecision attachment. In telescopic case, the largest mesio-inclined vertical displacement has been shown, so, the 1st premolar leaned mesial side. 3. Under tilting load, The pattern of displacement was similar in all four cases which appeared displaced to lingual side. But, the maximum displacement of 2nd premolar appeared larger than that of the first implant. Therefore, there was large discrepancy in displacement between natural tooth and implant during tilting load. 4. Under vertical load, the maximum compressive stress appeared at the 1st implant's neck. Semiprecision attachment case showed the largest maximum compressive stress, and the maximum compressive stress reduced in the order of precision attachment, telescopic and free-standing case. 5 Under vertical load, the maximum tensile stress appeared at the 2nd implant's distal neck. Semiprecision attachment case showed the largest maximum tensile stress, and the maximum tensile stress reduced in the order of precision attachment, telescopic and free-standing case. 6. Under vertical load or tilting load, principal stress appeared little between natural tooth & implant in free-standing case, but large principal stress was distributed at upper crown and distal contact site of the 2nd premolar in telescopic case. Principal stress appeared large at keyway & around keyway of distal contact site of the 2nd premolar in precision and semiprecision attachment case, appearing more broad and homogeneous in precision attachment case than in semiprecision attachment case.

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SWAT model calibration/validation using SWAT-CUP II: analysis for uncertainties of simulation run/iteration number (SWAT-CUP을 이용한 SWAT 모형 검·보정 II: 모의 실행 및 반복 횟수에 따른 불확실성 분석)

  • Yu, Jisoo;Noh, Joonwoo;Cho, Younghyun
    • Journal of Korea Water Resources Association
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    • v.53 no.5
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    • pp.347-356
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    • 2020
  • The main objective of the study is to propose the most efficient SWAT model calibration method using SWAT-CUP with less computing time and high performance. In order to achieve the goal, Case1-3 (250, 500, and 1,000 simulation runs) and Case4 (1,000 simulation runs in the first iteration and then 500 simulation runs for the following iterations) were defined to compare the results. When evaluating the values of the objective function, Case2 and Case3 reached the same value after the fourth iteration, and Case1 reached the closed value of Case2-3 after the eighth iteration. However, the final estimates of the parameters had different ranges in Cases1-3, and only the results of Case3 and Case4 converged similarly. Thus, it can be considered that the parameter calibration results are highly affected by the initial number of simulation runs. On the other hand, SWAT simulation results did not show the significant difference after the first iteration, unlike the parameter ranges. From the analysis results, we can conclude that the most suitable and effective method was to repeat one or two times of iterations with a sufficient number of simulation runs, as in Case4.

The effects of functional movement recovery of physical therapy after ACL reconstruction with MCL injury (물리치료가 슬관절 내측측부인대 손상을 동반한 전방십자인대 재건술 후 운동기능 회복에 미치는 영향)

  • Kim, In-Sup;Lim, Weon-Sik;Vae, Sung-Soo
    • The Journal of Korean Physical Therapy
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    • v.14 no.1
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    • pp.27-37
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    • 2002
  • This is the study of the knee joint injured patients at the orthopaedic surgery clinic where is located in Daejon, who has MCL combine injured ACL reconstruction caused by sport activity and accident during the period from Jan. 2001 to Oct. 2001. By comparing with groups between 7th case of I-group for MCL combined stitch and II-group for ACL reconstruction since 6weeks cast. We have been concluded with that following results. 1. Range of motion for the knee was not limited at 5th case(37%) of I-group, 6th case(42%) of II-group and the cases of Flexion deficit less then 10 -degree were 2nd case(13%) of I-group and II-group 1st case(8%) with no extension deficit more then 5 -degree. 2. The level of activity that tells you whether you are capable of exercise for six month after operation. It han been divided by 3 levels. The case of capable of doing low risk exercise(swimming, cycling, etc.) was 5th case of I-group, the case of capable of doing medium risk exercise(jogging, etc.) was 3rd case of I-group and 4th case of II-group and the case of capable of doing high risk exercise(football, etc.) were 3rd case of I-group and 3rd case of II-group. 3. The timing of the return to their job were average 6.4 weeks for I-group and average 22.9 weeks for II-group(P<.05, statistical difference). 4. There was no statistical difference between I-group and II-group for the timing of the return to their job(P>.05). 5. By using VAS to compare them there was no statistical difference between I-group and II-group of clinical results according to Lysholm scale.

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A Case Study of Platform Migration for an Object-Oriented CASE tool : OODesigner (객체지향 CASE 도구 OODesigner의 플랫폼 이식 사례 연구)

  • Hong, Euy-Seok;Kim, Tae-Gyun
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.9
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    • pp.2857-2866
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    • 2000
  • As software technology has made progress, object-oriented CASE tools have become more important. This paper presents the process and similarity in design and implementation of OODesigner, an object-oriented CASE tool, on three platfonns and outlines a kind of generic architecture for the design and the implementation of CASE tools. OODesigner is a tool that was initially developed to support OMT. An initial Unix version has been developed since 1994. In 1997, after the completion of the Unix version, we began developing a Java version and a Windows version supporting UML. The development of a CASE tool is a typical application of the Model-View-ControllerO'vIVC) paradigm. Thus, we obtained a common design pattern among the versions in the MVC point of views. This design similarity can be used to develop several kinds of CASE tools with the corresponding design notations.

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A Performance Study of Vent Mixer with Geometric Characteristics in Supersonic Flow (초음속 유동 내 벤트 혼합기의 형상적 특성에 따른 성능 연구)

  • Kim, Chae-Hyoung;Jeung, In-Seuck
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.1
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    • pp.69-75
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    • 2009
  • This paper studies the aerodynamic performance that the vent mixer-new conceptual supersonic mixer-showed with its geometric characteristics. The hole is 2 mm with 2 mm's distance from the wall in case 1 and with no distance in case 2. In case 3 die hole is 1 mm. Case 1 and case 2 showed the same total pressure recovery ratio, of which the case 3 was lower than that. While cases 1-3 had the same reattachment length, the shear layer was thicker in cases 1 and 2 than in case 3. Within the recirculation zone, cases 1 and 2 had lower pressure loss and higher velocity gradient difference than case 3-they enhance mixing between air and fuel. Separation bubble which is developed by the inflow into the recirculation zone has a significant effect on the total pressure recovery ratio in the combustor. Also separation bubble influences pressure distributions and recirculation flows in the recirculation zone. Therefore, inflow rate of air into the recirculation zone mainly affects the performance of vent mixer.

A Comparative Study on the Cases of Utilizing Type of Idle Farmlands (유휴농지 활용유형별 사례 비교 연구)

  • Kim, Kyoung-Chan;Jung, In-Ho;Koo, Seung-Mo
    • Journal of Korean Society of Rural Planning
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    • v.21 no.2
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    • pp.189-199
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    • 2015
  • This study made use of 9 types of utilizing idle farmland deducted from existing research in order to examine cases by type of idle farmland, and selected representative cases by type after analyzing contents of 165 available newspaper articles. Selected Cases were assorted into agricultural use and nonagricultural use, and agricultural use are as followed. (1)Community Service/Farming type is the case of Gimhae city reported on 'Busan Ilbo', (2)High Income/Farming type is the case of cooperative unit of Geumjeong crude drug in Yeongam appeared in 'Newsis', and the case of Omija industry in Mungyeong reported on 'Hankyoreh', (3)Tourism/Landscape/Farming type is the case of rape flowers and buckwheat flowers in Gupo village reported on 'Asia News Agency', (4)Stock Raising/Farming type is the case of growing foraging crops published in 'The Daejeon Ilbo', (5)Weekend farm type is the case of utilizing idle farmlands and creating weekend farm reported on 'Mediawatch', (6)High income/Forest type is creating Mulberry cultivation areas in Hamyang-Gun published in 'Yonhap News', (7)Ecology/Landscape/Forest type is forestation project of idle land reported on 'Newsis', (8)Agricultural Experience Study type is the case of managing agricultural experience study center in Dosun elementary center published in 'Sisajeju' and the case of non-agricultural application case, (9)Ecological Environment type is the case of wetland restoration of idle farmland in Gochang. This study investigated and arranged detailed contents by the literature search and interview investigation according to investigating items such as utilizing area, main agent, purpose, utilizing item, utilizing content, etc. by case. With that, it deducted implications as well as case characteristics, and finally suggested political proposals through the case analysis.