• Title/Summary/Keyword: 반복 충돌

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Scapula in Throwing Athletes

  • Choe, Chang-Hyeok
    • 대한정형외과스포츠의학회:학술대회논문집
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    • 2007.04a
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    • pp.52-57
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    • 2007
  • 투구운동은 견관절에 반복적인 압박력 및 신장력을 가하게 되며, 이는 견관절의 정적 안정력의 약화를 유발하게 된다. 초기의 경도의 불안정성은 근육 동 동적 안정력의 작용으로 안정적인 운동상태를 유지할 수 있으나, 반복적인 운동이 지속될 경우 근육이 피로해 져서 동적 안정력의 보상작용을 통한 안정성을 얻을 수 없게 된다. 이는 일차적으로 견관절의 불안정성을 유발할 뿐만 아니라, 이차적으로 견봉하충돌증후 및 내적충돌증후 등의 증상을 나타내기도 한다. 과 투구로 인한 대부분의 운동손상은 보존적 치료로 좋은 결과를 볼 수 있으며, 이는 일차적으로 투구를 중지하여 관절을 안정시키며 진통 소염제나 물리치료 등을 통한 항 염증치료, 그리고 회전건개 및 견갑골주위근육의 강화운동 둥의 단계로 진행된다. 적절한 보존적 치료에도 불구하고 증상이 지속될 경우 정확한 진단에 근거한 수술적 치료 및 조절된 재활운동 프로그램을 통해 조기 운동 복귀를 기대할 수 있다.

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Improvement in Inefficient Repetition of Gauss Sieve (Gauss Sieve 반복 동작에서의 비효율성 개선)

  • Byeongho Cheon;Changwon Lee;Chanho Jeon;Seokhie Hong;Suhri Kim
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.33 no.2
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    • pp.223-233
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    • 2023
  • Gauss Sieve is an algorithm for solving SVP and requires exponential time and space complexity. The terminationcondition of the Sieve is determined by the size of the constructed list and the number of collisions related to space complexity. The term 'collision' refers to the state in which the sampled vector is reduced to the vector that is already inthe list. if collisions occur more than a certain number of times, the algorithm terminates. When executing previous algorithms, we noticed that unnecessary operations continued even after the shortest vector was found. This means that the existing termination condition is set larger than necessary. In this paper, after identifying the point where unnecessary operations are repeated, optimization is performed on the number of operations required. The tests are conducted by adjusting the threshold of the collision that becomes the termination condition and the distribution in whichthe sample vector is generated. According to the experiments, the operation that occupies the largest proportion decreased by62.6%. The space and time complexity also decreased by 4.3 and 1.6%, respectively.

Biceps Pulley Impingement - Case Report - (이두박건 활차의 충돌 징후 - 증례보고 -)

  • Choi Chang-Hyuk;Kim Shin-Kun;Kang Byung-Kyu;Jang Woo-Chang
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.2 no.1
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    • pp.71-76
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    • 2003
  • We evaluated biceps pulley as a stabilizing sling for the long head of biceps tendon in the rotator interval. We present 3 cases of detached biceps pulley which impinges on posterosuperior glenoid labrum in the position of late cocking. Pulley impingement related to anterior shoulder instability was relieved after Bankart repair. In another two cases, impingement symptoms were disappeared after resection of the detached biceps pulley.

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Distance-based SAP Algorithm for Effective Collision Detection (효율적인 충돌 검출을 위한 거리 기반 SAP 알고리즘)

  • Oh, Min-Seok;Park, Sung-Jun
    • Journal of Korea Game Society
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    • v.12 no.4
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    • pp.23-31
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    • 2012
  • The collision processing is one of the essential factors to realize physical principles in the game, and it gives liveliness to the game. The collision processing requires a large amount of operations, and significantly affects the game performance. To address this problem, many studies have been conducted to reduce the operation volume, and the SAP algorithm is being widely used. However, its efficiency is low because it involves repetitive operations. In this study, a distance-based SAP algorithm was proposed to reduce the operation volume for the collision processing and address the problem of the SAP algorithm. A test was conducted to measure the FPS using the simulation program, which was developed with the proposed algorithm. The FPS was 2-33 times higher with the proposed algorithm, which indicated that the efficiency of the collision processing was improved.

Impact Tests and Numerical Simulations of Sandwich Concrete Panels for Modular Outer Shell of LNG Tank (모듈형 LNG 저장탱크 외조를 구성하는 샌드위치 콘크리트 패널의 충돌실험 및 해석)

  • Lee, Gye-Hee;Kim, Eun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.5
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    • pp.333-340
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    • 2019
  • Tests using a middle velocity propulsion impact machine (MVPIM) were performed to verify the impact resistance capability of sandwich concrete panels (SCP) in a modular liquefied natural gas (LNG) outer tank, and numerical models were constructed and analyzed. $2{\times}2m$ specimens with plain sectional characteristics and specimens including a joint section were used. A 51 kg missile was accelerated above 45 m/s and impacted to have the design code kinetic energy. Impact tests were performed twice according to the design code and once for the doubled impact speed. The numerical models for simulating impact behaviors were created by LS-DYNA. The external steel plate and filled concrete of the panel were modeled as solid elements, the studs as beam elements, and the steel plates as elasto-plastic material with fractures; the CSCM material model was used for concrete. The front plate deformations demonstrated good agreement with those of other tests. However the rear plate deformations were less. In the doubled speed test for the plain section specimen, the missile punctured both plates; however, the front plate was only fractured in the numerical analysis. The impact energy of the missile was transferred to the filled concrete in the numerical analysis.

Ship Collision Risk Analysis of Bridge Piers (선박충돌로 인한 교각의 위험도 분석)

  • Lee, Seong-Lo;Bae, Yong-Gwi
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.4
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    • pp.169-176
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    • 2005
  • An analysis of the annual frequency of collapse(AF) is performed for each bridge pier exposed to ship collision. From this analysis, the impact lateral resistance can be determined for each pier. The bridge pier impact resistance is selected using a probability-based analysis procedure in which the predicted annual frequency of bridge collapse, AF, from the ship collision risk assessment is compared to an acceptance criterion. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed AF is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The distribution of the AF acceptance criterion among the exposed piers is generally based on the designer's judgment. In this study, the acceptance criterion is allocated to each pier using allocation weights based on the previous predictions.

Design Vessel Selection of Maritime Bridges using Collision Risk Allocation Model (충돌위험분배모델을 이용한 해상교량의 설계선박 선정)

  • Lee, Seong-Lo;Lee, Byung Hwa;Bae, Yong-Gwi;Shin, Ho-Sang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.3
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    • pp.123-134
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    • 2006
  • In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of the maritime bridge. Method II which is a probability based analysis procedure is used to select the design vessel for collision impact from the risk analysis results. The analysis procedure, an iterative process in which a computed annual frequency of collapse(AF) is compared to the acceptance criterion, includes allocation method of acceptance criterion of annual frequency of bridge component collapse. The AF allocation by weights seems to be more reasonable than the pylon concentration allocation method because this AF allocation takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. From the assessment of ship collision risk for each bridge pier exposed to ship collision, a representative design vessel for all bridge components is selected. The design vessel size varies much from each other in the same bridge structure depending upon the vessel traffic characteristics.

Analysis of vehicle progress before and after a collision using simulation (시뮬레이션을 이용한 충돌 전후 차량 진행궤적 분석)

  • Han, Chang-Pyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.402-408
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    • 2021
  • Vehicle engineering analysis in the event of an accident caused by a car built on mechanical design has not been investigated in-depth but relies on the subjective experience knowledge of the investigator. This study analyzed the correlation between the speed, progress, steering, and braking before impact, which is consistent with the final stop position, by drawing a site situation chart using the CAD (CAD) program and repeating 250 crashes using the PC-Crash program. The following situations were investigated: lower impact velocity; greater impact speed of the vehicle, which is not affected significantly by the departure angle; higher vehicle speed, such as the effective impact velocity, after the impact; higher vehicle speed; and lower vehicle speed. (Ed note: I am unsure what you are saying here. It appears contradictory and not a complete sentence. Please check the changes.)The simulation results of this study identified the process of returning to the magnetic progression lane after recognizing the opposite porter while Mighty was carried out on the uphill left-curve section in a position that crossed the center line, and the collision of the porter's front left side, pushing the porter in the right diagonal direction and making the front stop towards approximately 11 o'clock.

Ship Collision Risk of Suspension Bridge and Design Vessel Load (현수교의 선박충돌 위험 및 설계박하중)

  • Lee, Seong Lo;Bae, Yong Gwi
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1A
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    • pp.11-19
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    • 2006
  • In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of suspension bridge. Method II in AASHTO LRFD bridge design specifications which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. From the assessment of ship collision risk for each bridge pier exposed to ship collision, the design impact lateral strength of bridge pier is determined. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed annual frequency of collapse(AF) is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. This AF allocation method is compared to the pylon concentration allocation method to obtain safety and economy in results. This method seems to be more reasonable than the pylon concentration allocation method because AF allocation by weights takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. The design vessel for each pier corresponding with the design impact lateral strength obtained from the ship collision risk assessment is then selected. The design impact lateral strength can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. Therefore more researches on the allocation model of AF and the selection of design vessel are required.

Exploiting Constraint for Iterative Improvement Search in Berth and Crane Scheduling (선석 및 크레인 일정계획에서 반복적 개선 탐색을 위한 제약조건의 활용)

  • 황준하;류광렬
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.10b
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    • pp.1-3
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    • 2001
  • 컨테이너 터미널에서의 선석 및 크레인 일정계획은 일정 기간 동안 입항 예정인 선박들을 대상으로 접안 위치와 접안 시기 및 기간을 결정하며, 또한 각 선박별로 컨테이너를 싣고 내릴 크레인을 배정하되 각 크레인의 서비스 시작과 완료시간가지 지정하는 전 과정을 포함한다. 이 문제는 여러 선박들 사이의 시간적 공간적 제약관계를 준수하고 크레인들을 충돌 없이 각 선박에 할당하여야 하는 제약조건 만족 문제인 동시에, 각 선박의 선호 위치와 희망 입출항 시간을 최대한 준수해야 하는 최적화 문제이기도 하다. 기존의 연구에서는 제약만족탐색기법을 사용하여 초기계획을 수립한 후 최적의 해를 유도해 내기 위해 휴리스틱 교정기법을 제약만족 탐색기법의 틀 내에서 반복적으로 적용하였다. 본 논문에서는 반복적 개선 탐색 도중에 도출되는 해의 정보를 이용하여 새로운 제약조건을 추가함으로써 다음 제약만족 탐색 시 보다 쉽게 더 충은 해를 찾을 수 있도록 하였으며 이 방법을 기존의 휴리스틱 교정기법과 결합하여 휴리스틱 교정기법의 성능을 향상시켰다.

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