• Title/Summary/Keyword: Long-term damage

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Long-Term Performance of Geosynthetic Reinforcement Materials with Field Installation Condition

  • Jeon, Han-Yong;Mok, Mun-Sung;Cho, Seong-Ho;Byun, Sung-Weon;Lee, Joon-Seok
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.10b
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    • pp.305-306
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    • 2003
  • In the case of the geosynthetics usage to soil structure, there are some damages by compaction. And these damages by the installation compaction result in the unexpected changes of short and long term properties of the structure. So in the case of index test, there are some problems to the exact evaluation on the installation damage. Therefore, to the more definite evaluation on the installation damage of geosynthetics, the real site installation damage test is encouraged. (omitted)

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Ship Motion-Based Prediction of Damage Locations Using Bidirectional Long Short-Term Memory

  • Son, Hye-young;Kim, Gi-yong;Kang, Hee-jin;Choi, Jin;Lee, Dong-kon;Shin, Sung-chul
    • Journal of Ocean Engineering and Technology
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    • v.36 no.5
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    • pp.295-302
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    • 2022
  • The initial response to a marine accident can play a key role to minimize the accident. Therefore, various decision support systems have been developed using sensors, simulations, and active response equipment. In this study, we developed an algorithm to predict damage locations using ship motion data with bidirectional long short-term memory (BiLSTM), a type of recurrent neural network. To reflect the low frequency ship motion characteristics, 200 time-series data collected for 100 s were considered as input values. Heave, roll, and pitch were used as features for the prediction model. The F1-score of the BiLSTM model was 0.92; this was an improvement over the F1-score of 0.90 of a prior model. Furthermore, 53 of 75 locations of damage had an F1-score above 0.90. The model predicted the damage location with high accuracy, allowing for a quick initial response even if the ship did not have flood sensors. The model can be used as input data with high accuracy for a real-time progressive flooding simulator on board.

Long-term Placement of Epidural Catheter - A case report - (경막외 카테터 초장기간 유치예에 대한 증례 보고)

  • Chae, Jung-Hae;Yoon, Duck-Mi;Oh, Hung-Kun
    • The Korean Journal of Pain
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    • v.3 no.1
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    • pp.59-62
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    • 1990
  • Epidural block is used for surgical analgesia, postoperative pain management, obstetric relief and management of chronic pain. Long-term pain control for chronic pain is achieved by development of epidural catheter placement technic. But long term placement of epidural catheteter has several problems, epidural hematoma, epidural absess and neural damage. We had successfully managed long-term placement of epidural catheter in patient with diabetic neuropathy who was susceptable to infection. The duration of epidural catheter placement was 416 days and specific complication was not occurred.

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Abusive Detection Using Bidirectional Long Short-Term Memory Networks (양방향 장단기 메모리 신경망을 이용한 욕설 검출)

  • Na, In-Seop;Lee, Sin-Woo;Lee, Jae-Hak;Koh, Jin-Gwang
    • The Journal of Bigdata
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    • v.4 no.2
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    • pp.35-45
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    • 2019
  • Recently, the damage with social cost of malicious comments is increasing. In addition to the news of talent committing suicide through the effects of malicious comments. The damage to malicious comments including abusive language and slang is increasing and spreading in various type and forms throughout society. In this paper, we propose a technique for detecting abusive language using a bi-directional long short-term memory neural network model. We collected comments on the web through the web crawler and processed the stopwords on unused words such as English Alphabet or special characters. For the stopwords processed comments, the bidirectional long short-term memory neural network model considering the front word and back word of sentences was used to determine and detect abusive language. In order to use the bi-directional long short-term memory neural network, the detected comments were subjected to morphological analysis and vectorization, and each word was labeled with abusive language. Experimental results showed a performance of 88.79% for a total of 9,288 comments screened and collected.

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Parameter Optimization of Long and Short Term Runoff Models Using Genetic Algorithm (유전자 알고리즘을 이용한 장·단기 유출모형의 매개변수 최적화)

  • Kim, Sun-Joo;Jee, Yong-Geun;Kim, Phil-Shik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.5
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    • pp.41-52
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    • 2004
  • In this study, parameters of long and short term runoff model were optimized using genetic algorithm as a basic research for integrated water management in a watershed. In case of Korea where drought and flood occurr frequently, the integrated water management is necessary to minimize possible damage of drought and flood. Modified TANK model was optimized as a long term runoff model and storage-function model was optimized as a short term runoff model. Besides distinguished parameters were applied to modified TANK model for supplementing defect that the model estimates less runoff in the storm period. As a result of application, simulated long and short term runoff results showed 7% and 5% improvement compared with before optimized on the average. In case of modified TANK model using distinguished parameters, the simulated runoff after optimized showed more interrelationship than before optimized. Therefore, modified TANK model can be applied for the long term water balance as an integrated water management in a watershed. In case of storage-function model, simulated runoff in the storm period showed high interrelationship with observed one. These optimized models can be applied for the runoff analysis of watershed.

Tunnel Stability Assessment Considering Rock Damage from Blasting Near to Excavation Line (굴착선 주변공 발파의 암반손상을 고려한 터널 안정성 검토)

  • 이인모;윤현진;이형주;이상돈;박봉기
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.167-178
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    • 2003
  • Damage and overbreak of the remaining rock induced by blasting can not be avoided during tunnel construction which may result in either short-term or long-term tunnel instability. Therefore, in this paper, a methodology to take into account the effect of blast-induced damage in tunnel stability assessment is proposed. Dynamic numerical analysis was executed to evaluate damage and overbreak of the remaining rock for the most common blasting pattern in road tunnel. Rock damage was quantified by utilizing the damage variable factor which is adopted proposed in continuum damage mechanics. The damaged rock stiffness and the damaged failure criteria are used to consider the effect of rock damage in tunnel stability analysis. The damaged geological strength index of the damaged rock was newly proposed from the relationship between deformation modulus and geological strength index. Also the Hoek-Brown failure criteria of the damaged rock was obtained using the damaged geological strength index. Analysing the tunnel stability with the consideration of the blast-induced damage of remaining rock, it was found that the extend of plastic zone and deformation increased compared to the undamaged rock. Therefore the short-term or long-term tunnel stability will be threatened when the rock damage from blasting is ignored in the tunnel stability analysis.

Long-Term Preservation Measures of Paper Records of Special Preserving Organization (특수 보존 기관의 종이 기록물 장기 보존 대책)

  • Shin, Jong-Soon;Lee, Jae-Soo
    • Journal of the Korean Graphic Arts Communication Society
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    • v.30 no.1
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    • pp.59-69
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    • 2012
  • This study is Long term preservation measures which is closely related to preserving paper records, record condition evaluation, preservation measure and is conducted as follows. As for Means to Evaluate the Deterioration and Damaged Conditions of Records, research and analysis has been made on the contamination and deterioration examples such as damage, dry, stapler, metal, contamination, acidification which are the characteristics of paper record damage types. The of Paper record is one of the key procedures to evaluate the record material and its physi-chemical status in many criteria and to suggest the best preservation method. Between 1970 and 2000, the main record materials was fine paper and OMR paper along with partly newspaper and coarse paper, whereas the main recording material was ball point pen. Overall damage and deterioration status is, for record materials between 1940 and 1960, high deterioration was found and in urgent need for preservation measure and more damages are caused by tapes, staplers and metals. As for records after 1970, there is light deterioration but needs preservation process. There are approximately 3 million records produces before 2000, and assuming that there are 30 pages per record and that 30% has been damaged or deteriorated, 27 million pages are subject to preservation process. Among damaged or deteriorated records, there are large number of records impossible to go through deacidification process so manual preservation and restoration process is necessary as well. Securing manpower having preservation and restoration skills as well as preservation equipment(deacidification process, preservation and restoration) is in urgent need.

Development of a numerical modelling technique for evaluation of a long-term chemical deterioration of tunnel shotcrete lining (터널 숏크리트 라이닝의 장기 화학적 열화 손상 평가를 위한 수치 모델링 기법 개발)

  • Shin, Hyu-Soung;Kim, Dong-Gyou
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.3
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    • pp.299-307
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    • 2007
  • In this study, a new concept for simulating a physical damage of tunnel shotcrete lining due to a long-term chemical deterioration has been proposed. It is known that the damage takes place mainly by internal cracks, reduction of stiffness and strength, which results mainly from volume expansion of the lining and corrosion of cement materials, respectively. This damage mechanism of shotcrete lining appears similar in most kinds of chemical reactions in tunnels. Therefore, the mechanical deterioration mechanism induced by a series of chemical reactions was generalized in this study and mathematically formulated in the framework of thermodynamics. The numerical model was implemented to a 3D finite element code, which can be used to simulate behaviour of tunnel structures undergoing external loads as well as chemical deterioration in time. A number of illustrative examples were given to show a feasibility of the model in tunnel designs.

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Model to Determine Long-term Allowable Strength of Geosynthetics Reinforcements Considering Strain Compatibility (변형률 적합성을 고려한 토목섬유 보강재의 장기허용강도 결정 모델)

  • Jeon, Han-Yong;Yuu, Jung-Jo;Mok, Mun-Sung
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1580-1587
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    • 2005
  • To calculate the long-term allowable strength of geosynthetic reinforcement, replacement method was recommended. The isochronous creep curve by S. Turner was used to define the relation between creep strain and allowable strength. In isochronous curve at given time, one can read the allowable strength at allowable creep strain. The allowable strain gets from specification by directors or manufacturers according to the allowable displacement of reinforced structures. The allowable strength can be determined in relation to the allowable horizontal displacement each structures case by case. The effect of install damage on isochronous behaviors of geosynthetic reinforcement was little. In previous study, install damage increase the creep strain slightly. And the degradation was not identified. But it is supposed that degradation increase the creep strain. In conclusion, The recommended model to determine long-term allowable strength of geosynthetic reinforcements considering tensile deformation of reinforcement and soil is fit for proper, correct and economic design for reinforced earth walls.

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