• Title/Summary/Keyword: Repeated use

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Evaluation of Impact resistance of UHPC Under Repeated Impact (반복충격을 받은 UHPC의 내충격성능 평가)

  • Jeong, Min-Seung;Kim, Gyu-Yong;Lee, Sang-Kyu;Hwang, Eui-Chul;Kim, Gyeong-Tae;Nam, Jeong-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.161-162
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    • 2018
  • In this study, it evaluate the impact resistance of UHPC by repeated impact. smooth steel fiber and polyvinyl alcohol fiber were reinforced in UHPC respectively. Overall, the impact resistance of the specimens reinforced with 0.4vol.% PVA fiber was high, and the crater diameter was small in specimens using 13mm fiber. When 19 mm steel fiber is used, the fracture depth is small due to the increase of macro crack resistance compared with other specimens. On the other hand, in the case of the fracture area, it is considered that the use of the fiber of 13 mm causes an increase in the stress dispersion effect to occur small.

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Shape optimization by the boundary element method with a reduced basis reanalysis technique

  • Leu, Liang-Jenq
    • Structural Engineering and Mechanics
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    • v.8 no.1
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    • pp.73-84
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    • 1999
  • This paper is concerned with shape optimization problems by the boundary element method (BEM) emphasizing the use of a reduced basis reanalysis technique proposed recently by the author. Problems of this class are conventionally carried out iteratively through an optimizer; a sequential quadratic programming-based optimizer is used in this study. The iterative process produces a succession of intermediate designs. Repeated analyses for the systems associated with these intermediate designs using an exact approach such as the LU decomposition method are time consuming if the order of the systems is large. The newly developed reanalysis technique devised for boundary element systems is utilized to enhance the computational efficiency in the repeated system solvings. Presented numerical examples on optimal shape design problems in electric potential distribution and elasticity show that the new reanalysis technique is capable of speeding up the design process without sacrificing the accuracy of the optimal solutions.

Robust Control for Singularly Perturbed Uncertain Systems with State Constraints

  • Lee, Sang-Yup;Kim, Eung-Ju;Kim, Beom-Soo;Lim, Myo-Taeg
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.34.1-34
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    • 2001
  • We deal with robust control problem for singularly perturbed linear systems with norm-bounded structured uncertainty under state constraints. We assume that the norm-bounded uncertainty is composed of repeated scalar-block and full-block forms. In the structured uncertainty, repeated scalar block forms account for uncertain physical parameter value and full-block forms may be some unknown nonlinear dynamics. In order deal with uncertainty and state constraints, we use LMI(Linear Matrix Inequality). The original problem is decomposed into two well behaved reduced order problems. Shinc two LMI problems are completely independent, each solution can be computed simultaneously and work in parallel.

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Study of Sugarcane Pieces as Yeast Supports for Ethanol Production from Sugarcane Juice and Molasses Using Newly Isolated Yeast from Toddy Sap

  • Babu, Neerupudi Kishore;Satyanarayana, Botcha;Balakrishnan, Kesavapillai;Rao, Tamanam Raghava;Rao, Gudapaty Seshagiri
    • Mycobiology
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    • v.40 no.1
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    • pp.35-41
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    • 2012
  • A repeated batch fermentation system was used to produce ethanol using $Saccharomyces$ $cerevisiae$ strain (NCIM 3640) immobilized on sugarcane ($Saccharum$ $officinarum$ L.) pieces. For comparison free cells were also used to produce ethanol by repeated batch fermentation. Scanning electron microscopy evidently showed that cell immobilization resulted in firm adsorption of the yeast cells within subsurface cavities, capillary flow through the vessels of the vascular bundle structure, and attachment of the yeast to the surface of the sugarcane pieces. Repeated batch fermentations using sugarcane supported biocatalyst were successfully carried out for at least ten times without any significant loss in ethanol production from sugarcane juice and molasses. The number of cells attached to the support increased during the fermentation process, and fewer yeast cells leaked into fermentation broth. Ethanol concentrations (about 72.65-76.28 g/L in an average value) and ethanol productivities (about 2.27-2.36 g/L/hr in an average value) were high and stable, and residual sugar concentrations were low in all fermentations (0.9-3.25 g/L) with conversions ranging from 98.03-99.43%, showing efficiency 91.57-95.43 and operational stability of biocatalyst for ethanol fermentation. The results of the work pertaining to the use of sugarcane as immobilized yeast support could be promising for industrial fermentations.

Three Dimensional Thermal Cycle Analysis of Mold in Repeated Forming Process of TV Glass (TV 유리의 반복 성형공정에서 3차원 금형 열사이클 해석)

  • Hwang, Jung-Hea;Choi, Joo-Ho;Kim, Jun-Bum
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.192-198
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    • 2000
  • Three dimensional thermal cycle analysis of the plunger is carried out in repeated forming process of the TV glass, which is continued work of two dimensional analysis where an efficient method has been proposed. The plunger undergoes temperature fluctuation during a cycle due to the repeated contact and separation from the glass, which attains a cyclic steady state having same temperature history at every cycle. Straightforward analysis of this problem brings about more than 90 cycles to get reasonable solution. An exponential function fitting method is proposed, which finds exponential function to best approximate temperature values of 3 consecutive cycles, and new cycle is restarted with the fitted value at infinite time. Number of cases are analyzed using the proposed method and compared to the result of straightforward repetition, from which one finds that the method always reaches nearly convergent solution within $9{\sim}12$ cycles, but turns around afterwards without further convergence. Two step use is found most efficient, in which the exponential fitting is carried out fer the first 12 cycles, followed by simple repetition, which shows fast convergence expending only 6 additional cycles to get the accuracy within 2 error. This reduces the computation cycle remarkably from 90 to 18, which is 80% reduction. From the parametric studies, one reveals that the overall thermal behavior of the plunger in terms of cooling parameters and time is similar to that of 2 dimensional analysis.

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Long-term repeated rituximab treatment for childhood steroid-dependent nephrotic syndrome

  • Kim, Ji Hyun;Park, Eujin;Hyun, Hye Sun;Cho, Myung Hyun;Ahn, Yo Han;Choi, Hyun Jin;Kang, Hee Gyung;Ha, Il-Soo;Cheong, Hae Il
    • Kidney Research and Clinical Practice
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    • v.36 no.3
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    • pp.257-263
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    • 2017
  • Background Rituximab (RTX) can be used as a rescue therapy for steroid-dependent nephrotic syndrome (SDNS). However, the efficacy and safety of long-term, repeated use of RTX are not established. This study was conducted to assess the efficacy and safety of long-term, repeated RTX treatment in children. Methods Eighteen consecutive child patients with SDNS who were treated with three or more cycles of RTX for one year or longer were recruited, and their medical records were retrospectively reviewed. Results The patients were followed for $4.7{\pm}1.9years$ and received $5.2{\pm}2.3cycles$ of RTX over $2.8{\pm}1.1years$. Approximately 70% of the additional RTX cycles were administered due to recovery of B-cells without relapse. The relapse rate decreased from $3.4{\pm}2.0per$ year initially to $0.4{\pm}0.8per$ year at the third year after RTX treatment. Approximately 10% of the RTX infusions were accompanied by mild infusion reactions. Eight patients showed sustained remission without any oral medication after the last cycle of RTX, while 10 patients had one or more episodes of relapse after the last cycle of RTX. The relapse rate in the latter group decreased from $2.8{\pm}1.5per$ year before RTX treatment to $1.3{\pm}0.8per$ year after cessation of RTX treatment. No significant differences in clinical parameters were found between the two groups. Conclusion This retrospective study showed that pre-emptive and long-term, repeated RTX treatment is relatively effective and safe in children with SDNS. However, well-designed prospective studies are needed to confirm these findings.

A Study of Geographic Information Organization of Internet Resources (인터넷 지리정보 체계화에 대한 연구)

  • Kwak Chul-Wan
    • Journal of Korean Library and Information Science Society
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    • v.37 no.2
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    • pp.255-272
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    • 2006
  • This study was investigated to the geography services and geographical directories through Internet in order to develop a geographical directory. Research method was the examination of different type of geography services through internet and geographical directories on the Internet search engines. The results show principles for a geographical directory construction: use both geographical names and subject names on the initial directory screen, repeated use the names through directory hierarchy, locality use on bottom directory as a geographical name, and fit use of the number of directories.

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Empowering Intercultural Communicative Competence through Metacognitive Reading Strategy

  • Chang, Hyung-Ji
    • English Language & Literature Teaching
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    • v.18 no.2
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    • pp.1-20
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    • 2012
  • This study aims to propose using English reading strategies to enhance Intercultural Communicative Competence (ICC) for EFL learners. The study recruited college-level participants who were enrolled in a general English reading course (N=30) and administrated the surveys with a Repeated Measures Design (RMD). In the survey, an intercultural sensitivity scale and metacognitive reading strategies inventory were conducted for comparison. During the instruction, participants were asked to use the R.I.D.E.R. (i.e. Read, Image, Describe, Evaluate, and Repeat) strategy for visualization of text, which is aimed at facilitating the use of metacognitive reading strategies. In the results, participants showed a statistically significant increase both in the intercultural sensitivity level and the use of metacognitive reading strategies after the practice of R.I.D.E.R for one semester. Further analysis was appended to the results by the correlation and regression analysis, and proposed that participants benefit their development of intercultural sensitivity from the use of metacognitive reading strategies. Therefore, the study suggests that implementing metacognitive reading strategies facilitates college EFL readers to increase their cultural sensitivity, which empowers ICC through English reading (176words).

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A Study on the Spatial Use Patterns of the Demented Elderly in Skilled Nursing Facilities (노인전문요양시설 치매노인의 공간이용패턴에 관한 연구)

  • Yang, Kum-Suek
    • Journal of the Korean Institute of Rural Architecture
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    • v.8 no.2
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    • pp.36-45
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    • 2006
  • The purpose of this study is to clarify the spatial use pattern changes over time in skilled nursing facility. The investigation had been executed against the elderly(65 and over) in skilled nursing facility. This article discuss the basic characteristics of the elderly with dementia and the daily living activities of the elderly with dementia at skilled nursing facility in Jangseong-gun. The survey was repeated 2 times at the period of 61 months and 88 months after the opening of the facility. Changes over time of the spatial use patterns are clarified. Some results show as follows: (1)As the time went by, there is wide difference between behavioral places and nursing levels on the living activities of the elderly with dementia. (2)As the time went by, the elderly who have a tendency to stay in his bedroom through the greater part of the days.

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Effects of Metamemory and Mnemonic Strategy Training on Children's Performance (아동의 상위기억과 책략훈련에 관한 연구)

  • Chung, Hyun Joo;Lee, Young
    • Korean Journal of Child Studies
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    • v.12 no.1
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    • pp.21-37
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    • 1991
  • The present research studied the effectiveness of specific strategy training in memory awareness on children's memory performance. The subjects were 60 children, 30 six-year-olds and 30 eight-year-olds. Free recall scores and use of a rehearsal strategy (exposure durations) based on Belmont & Butterfield (1971) were used to measure children's performance in three memory tasks. All subjects were randomly assigned to one of three experimental groups: the control group with no training, the chunking and rehearsal strategy training group, and the chunking and rehearsal strategy training combined with memory awareness strategy. The data were analyzed with two-way ANOVA, three-way ANOVA with repeated measures, and Student-Newman-Keuls post hoc test. There were significant differences among the three groups both in the free recall score and in the use of the rehearsal strategy. The mnemonic strategic training with memory awareness strategy was the most effective on both free recall and use of rehearsal strategy. The effects of the mnemonic strategy training with memory awareness strategy were more effective for the 8-year-olds than the 6-year-olds.

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