• Title/Summary/Keyword: Repetitive loading

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Posterior and Multidirectional Instability

  • Kim, Seung-Ho
    • The Academic Congress of Korean Shoulder and Elbow Society
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    • 2005.11a
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    • pp.78-93
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    • 2005
  • The posterior and multidirectional instability of the shoulder is a complex problem in terms of diagnosis and treatment. Increased joint volume by redundant capsular ligament has been regarded as a major pathogenesis of the posterior and multidirectional instability. Distinct from multidirectional hyperlaxity, multidirectional instability has symptoms related with increased translations in more than one direction. Recent report that shoulder symptom originates from labral lesion which was created by excessive rim-loading of the humeral head on the posteroinferior glenoid labrum during repetitive subluxation helps us to understand the pathogenesis of such instability. Painful jerk and Kim tests indicate labral lesion in the multidirectionally loose shoulder, suggesting multidirectional instability. Also, painful jerk test is a prognostic sign of failure of nonoperative treatment. The labral lesion can be an incomplete tear or a concealed lesion which often has been underestimated. Operative treatment is indicated when nonoperative treatment has failed. Arthroscopic capsulolabroplasty is a reliable procedure, which not only provides capsular balance, but also restores the labral height.

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Prediction of Tractive Performance of Off-Road Wheeled Vehicles (로외에서 운용되는 휠형차량의 견인성능 예측)

  • 박원엽;이규승
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.5
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    • pp.188-195
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    • 2000
  • This study was conducted to develop the mathematical model and the computer simulation program(TPPMWV) for predicting the tractive performance of off-road wheeled vehicles operated on various soil conditions. The model takes into account main design parameters of a wheeled vehicle, including the radius and width of front and rear tires, the weight of vehicle, wheelbase and driving type(4WD, 2WD). Soil characteristics, such as the peressure-sinkage and shearing characteristics and the response to repetitive loading, are also taken into consideration. The effectiveness of the developed model was verified by comparing the predicted drawbar pulls using TPPMWV with measured ones obtained by field tests for two different driving types of wheeled vehicle. As a results, the drawbar pulls predicted by the TPPMWV were well matched to the measured ones within the absolute errors of 5.25%(4WD) AND 9.42%(2WD)for two different driving types, respectively.

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Application of Geotextile to ensure the Motor Pouring Ability for Paved Track (포장궤도 모르터 충진성능 확보를 위한 토목섬유의 적용)

  • Lee Ho-Ryong;Park Jong-Kyan;Hwang Seon-Keun;Lee Il-Wha
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.836-841
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    • 2005
  • As gravel roadbed is gradually turn down by repetitive loading of train, lasting work for maintenance and management of track is necessary to reduce the settlement of roadbed and the deterioration of track. Despite of above weak point, gravel roadbed has become a basic structure of roadbed at the present time. But request for new structure of roadbed is recently presented to settle an increased transportation capacity of track, and to solve a shortage of the labor to handle maintenance work of track. Therefore, we begin to research about maintenance-free roadbed like paved track from two years ago. In this study, a series of tests were performed to clarify the characteristics of strength and permeability of concrete specimen, which is the upper part of paved track injected by cement mortar, by type of geotextile and finally to give a basic data for application of geotextile to the lower part of paved track.

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Osteochondral Lesions of the Talus (거골의 골연골 병변)

  • Lee, Keun-Bae
    • Journal of Korean Foot and Ankle Society
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    • v.16 no.1
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    • pp.9-18
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    • 2012
  • Osteochondral lesions of the talus are isolated cartilage and/or bone lesions that are known cause of chronic ankle pain. They can occur as the result of a single acute ankle injury or from repetitive loading of the talus. Technical development in radiologic imaging and ankle arthroscopy have improved diagnostic capabilities for detecting osteochondral lesions. Characteristics which are important in assessing an osteochondral lesions include: the size, the type (chondral, subchondral, cystic), the stability, the displacement, the location, and the containment of lesion. Nonoperative treatment involving period of casting and non-weight-bearing is recommended for acute, non-displaced osteochondral lesions in select pediatric and adolescent patients. Operative treatment is recommended for unstable lesions or failed conservative management. Marrow stimulation techniques (abrasion chondroplasty, multiple drilling, microfracture), osteochondral autograft or allograft, autologous chondrocyte implantation, are frequently employed. The purpose of this article is to review the historical background, etiology, classification systems, diagnostic strategies, and to describe a systematic approach to management of osteochondral lesions of the talus.

Design of Emulator using DSP Chip (DSP 칩을 이용한 에뮬레이터 설계)

  • Lee, Dae-Young;Lee, Jae-Hak;Kim, Jin-Min;Kim, Hyoun-Ho;Bae, Hyeon-Deok
    • Proceedings of the KIEE Conference
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    • 1993.07a
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    • pp.453-455
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    • 1993
  • In this research, the digital signal processing PC board which employs TI's TMS320C25 is implemented. The board can perform following functions. spectrum analysis of speech and repetitive signal, digital filters emulation by convolution, signal generation of sinusoidal wave, rectangular wave etc.. In this system, communications between PC and DSP board. program down-loading to DSP board and recording and graphic of acquired and processed data in DSP board are executed by PC. Parallel interface and buffer memory are used in communications. Data acquisition and operation are carried out in DSP board. Resultant data are transmitted to PC and output through DAC.

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Prdiction of Tractive Performance of Wheeled Vehicles on Soft Terrains (휠형차량의 연약지 견인성능 예측)

  • 박원엽;이규승
    • Journal of Biosystems Engineering
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    • v.25 no.5
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    • pp.359-368
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    • 2000
  • In this paper, mathematical model was developed for predicting the tractive performance of off-road wheeled vehicles operated on soft terrains. Based on the mathematical model, a computer simulation program(TPPMWV) was developed. The model takes into account main design parameters of wheeled vehicle, including radius and width of front and rear tire, weight of vehicle, wheelbase and driving type(4WD, 2WD). Soil characteristics, such as the peressure-sinkage and shearing characteristics and the response to repetitive loading and slip-sinkage effect, are also taken into consideration. The effectiveness of the developed model was verified by comparing the predicted drawbar pulls using TPPMWV with measured ones obtained by field tests for two different driving types of wheeled vehicle. As a results, the drawbar pulls predicted by the TPPMWV were well matched to the measured ones within the absolute errors of 3.916%(4WD) and 13.31%(2WD) for two different driving types, respectively.

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Intravenous levetiracetam versus phenobarbital in children with status epilepticus or acute repetitive seizures

  • Lee, Yun-Jeong;Yum, Mi-Sun;Kim, Eun-Hee;Ko, Tae-Sung
    • Clinical and Experimental Pediatrics
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    • v.59 no.1
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    • pp.35-39
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    • 2016
  • Purpose: This study compared the efficacy and tolerability of intravenous (i.v.) phenobarbital (PHB) and i.v. levetiracetam (LEV) in children with status epilepticus (SE) or acute repetitive seizure (ARS). Methods: The medical records of children (age range, 1 month to 15 years) treated with i.v. PHB or LEV for SE or ARS at our single tertiary center were retrospectively reviewed. Seizure termination was defined as seizure cessation within 30 minutes of infusion completion and no recurrence within 24 hours. Information on the demographic variables, electroencephalography and magnetic resonance imaging findings, previous antiepileptic medications, and adverse events after drug infusion was obtained. Results: The records of 88 patients with SE or ARS (median age, 18 months; 50 treated with PHB and 38 with LEV) were reviewed. The median initial dose of i.v. PHB was 20 mg/kg (range, 10-20 mg/kg) and that of i.v. LEV was 30 mg/kg (range, 20-30 mg/kg). Seizure termination occurred in 57.9% of patients treated with i.v. LEV (22 of 38) and 74.0% treated with i.v. PHB (37 of 50) (P=0.111). The factor associated with seizure termination was the type of event (SE vs. ARS) in each group. Adverse effects were reported in 13.2% of patients treated with i.v. LEV (5 of 38; n=4, aggressive behavior and n=1, vomiting), and 28.0% of patients treated with i.v. PHB (14 of 50). Conclusion: Intravenous LEV was efficacious and safe in children with ARS or SE. Further evaluation is needed to determine the most effective and best-tolerated loading dose of i.v. LEV.

Bearing Capacity Analysis on Cyclic Loading of Soft Ground by Surface Reinforcement (표층처리지반에서의 반복하중재하시험을 통한 지지력 분석)

  • Kwak, Nokyung;Park, Minchul;Lee, Song
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.6
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    • pp.5-17
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    • 2012
  • The study of surface ground reinforcing method is supposed to be considered preferentially is not satisfied and also doesn't contemplate plastic flow because of repetitive drive of construction equipment. Also, Terzaghi's bearing-capacity equation and Yamanouchi's suggestion have been used to design the surface reinforcement, but most engineers depend on their experience and cases constructed before because of dispersed variables and inappropriate bearing-capacity factors. Hence, plate load test and repetitive plate load test were performed in the field which is reinforced with geotextile, Geogrid whose tensile strength are 200kN/m, 100kN/m and bamboo($0.4m{\times}0.4m$). The object of this study is to evaluate bearing capacity and behaviour of surface ground and to compare each reinforcement form test results. From the results bearing capacity ratio increased by a maximum of 1.5 times with bamboo reinforcement method comparing to others.

Optimal Stiffness Design of Self-Piercing Riveting's C-Frame for Multimaterial Joining (다종소재 접합을 위한 SPR(Self-Piercing Riveting)용 C-프레임 강성 최적설계)

  • Shin, Chang-Yeul;Lee, Jae-Jin;Mun, Ji-Hun;Kwon, Soon-Deok;Yang, Min-Seok;Lee, Jae-Wook
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.5
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    • pp.76-84
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    • 2021
  • In this study, an optimal stiffness model of the C-frame, which was supporting the mold and tool load, was proposed to obtain quality self-piercing riveting (SPR) joining. First, the load path acting on the C-frame structure was identified using topology optimization. Then, a final suggested model was proposed based on the load path results. Stiffness and strength analyses were performed for a rivet pressing force of 7.3 [t] to compare the design performance of the final proposed model with that of the initial model. Moreover, to examine the reliability of continuous and repeated processes, vibration analysis was performed and the dynamic stiffness of the final proposed model was reviewed. Additionally, fatigue analysis was performed to ascertain the fatigue characteristics due to simple repetitive loading. Finally, stiffness test was performed for the final proposed model to verify the analysis results. The obtained results differed from the analysis result by 2.9%. Consequently, the performance of the final proposed model was superior to that of the initial model with respect to not only the SPR fastening quality but also the reliability of continuous and repetitive processes.

Load Carrying Capacity of Geosynthetic Reinforced Railway Subgrade Under Cyclic Load (토목섬유 보강재로 보강된 철도 노반의 반복하중 하중지지력 연구)

  • Hong, SeungRok;Cho, Yungyu;Choi, JungHyuk;Jeong, Yongjun;Yoo, ChungSik
    • Journal of the Korean Geosynthetics Society
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    • v.12 no.4
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    • pp.109-121
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    • 2013
  • This paper studied the characteristics of bearing capacity of railway reinforced with geosynthetic against repetitive loading of train. The railway that was based on the porous pavement substructure ground and reinforced with geosynthetic was copied. In order to analyze load carrying capacity of geosynthetic, we have had 3cases experiments - in the first case, the ground was non reinforced, second case was reinforced geocell and last case was reinforced geogrid - and all of them were reduced-scale laboratory tests. The results of the analyses indicated that the bearing capacity of the reinforced geogrid increases much more than the reinforced geocell. Residual deformation of the initial cyclic load was larger than the secondary cyclic loads.